CN101080471A - Polyimide multilayer adhesive film and its manufacturing method - Google Patents

Abstract

The object of the present invention is to provide a polyimide multilayer adhesive film capable of accurately measuring the thickness of each layer by an infrared absorption method, and a method for producing the same. The adhesive film comprises a highly heat-resistant polyimide layer and an adhesive layer containing a thermoplastic polyimide formed on at least one surface of the highly heat-resistant polyimide layer, wherein the adhesive film is produced by a coextrusion-casting coating method, and either the highly heat-resistant polyimide layer or the adhesive layer contains a polyimide resin containing a functional group exhibiting a characteristic infrared absorption wavelength as a main component; in the subsequent film thickness measuring step, the film thickness of each layer is measured by an infrared absorption film thickness meter, and the film thickness of each layer at the time of film formation is controlled and adjusted based on the obtained film thickness dimension data, thereby providing the polyimide multilayer adhesive film of the present invention.

Description

Polyimide multilayer adhesive film and its manufacturing method

technical field

The present invention relates to a multilayer adhesive film in which an adhesive layer containing thermoplastic polyimide is provided on at least one side of a high heat-resistant polyimide layer and the film thickness of each layer is controlled. Thick film technology.

Background technique

In recent years, with the reduction in weight, miniaturization, and high density of electronic products, the demand for various printed circuit boards has increased, and the demand for flexible laminates (also called flexible printed circuit boards (FPC), etc.) has particularly increased. . The flexible laminate has a structure in which a circuit including metal foil is formed on an insulating film.

The above-mentioned flexible laminate is generally formed of various insulating materials, and a flexible insulating film is used as a substrate. On the surface of the substrate, metal foil is heated and pressed by various adhesive materials to make it bonded. combined method to manufacture. As the insulating film, a polyimide film or the like is preferably used. As the adhesive material, thermosetting adhesives such as epoxy and acrylic are generally used (FPCs using these thermosetting adhesives are also referred to as three-layer FPC hereinafter).

Thermosetting adhesives have the advantage of being able to bond at lower temperatures. However, as the requirements for heat resistance, flexibility, and electrical reliability become stricter in the future, it is considered difficult to meet the requirements for three-layer FPC using thermosetting adhesives. In response to this, a material in which a metal layer is directly laminated on an insulating film, and an FPC in which a thermoplastic polyimide compound is used on an adhesive layer (hereinafter also referred to as a two-layer FPC) have been proposed. This two-layer FPC has characteristics superior to those of the three-layer FPC, and is expected to be an industrially useful product.

Examples of methods for producing flexible metal bonded laminates for two-layer FPC include casting on metal foil, applying polyamic acid as a precursor of polyimide compounds, and then imidizing. The sputtering and plating method is a metal spraying method in which a metal layer is directly provided on a polyimide film, and the lamination method is a lamination method in which a thermoplastic polyimide compound is used to bond a polyimide film and a metal foil. Among them, the lamination method has the following advantages: the thickness range of the metal foil that meets the requirements is wider than that of the casting method, and the device cost is lower than that of the metal spraying method. As an apparatus for performing lamination, a hot roll lamination apparatus, a double-belt press apparatus, or the like that continuously laminates while sending out roll-shaped materials one after another can be used.

Here, as a substrate material used in the lamination method, a multilayer adhesive film (hereinafter referred to as an adhesive film) in which a thermoplastic polyimide compound layer is provided on at least one surface of a polyimide film can be widely used.

As a method of manufacturing an adhesive film using such a polyimide film as a base material, there are the following methods: 1) On one side or both sides of the high heat-resistant polyimide film as the base material, use a roll coater or A coating method in which a thermoplastic polyimide compound or its precursor in a solution state is applied by a die-type coater, and then dried; using a different extrusion die will become a high heat resistance of the base material Solution of polyimide compound and/or precursor solution (hereinafter referred to as "high heat-resistant polyimide compound varnish") and solution of thermoplastic polyimide compound and/or precursor solution (hereinafter referred to as "thermoplastic polyimide compound varnish") is extrusion-molded, dies are arranged side by side in the production direction of the film, and the film is laminated and dried to produce a simultaneous extrusion film-making method; Extrusion film manufactured by forming a high heat-resistant polyimide compound varnish into a film with a compression molding die, applying a thermoplastic polyimide compound varnish with a roll coater or die coater, and drying it Simultaneous coating method. In addition, a thermal lamination method in which a thermoplastic polyimide film is thermally bonded to one side or both sides of a highly heat-resistant polyimide film serving as a base material, and processed and manufactured is also mentioned.

Adhesive films obtained by these methods must improve the adhesion between different types of polyimide resins, but generally speaking, the adhesion between different types of polyimide resins is poor, and it is difficult to obtain adhesive films of sufficient strength. Co-membrane. As a method of improving the adhesiveness between different types of polyimide resins, it is most effective to produce an adhesive film by using a solution containing different types of polyimide resins and/or containing its precursor solution to form a multilayer liquid film, which is cast onto a smooth substrate, and then heated and dried to form an adhesive film. As a method for forming a multilayer liquid film, the following known methods can be mentioned: a co-extrusion film forming method using a multilayer die for extrusion molding (for example, Patent Documents 1 and 2), and a method using a sliding die (slidedie). method (for example, Patent Document 3), sequential coating method, and the like.

There is a problem in the above-mentioned production method that it is difficult to adjust the thickness of the continuously produced adhesive film approximately in real time. In order to adjust the thickness of a continuously produced adhesive film approximately in real time, it is necessary to accurately measure the thickness of each layer of the adhesive film on-line. However, in the past, it was extremely difficult to accurately measure the thickness of each layer of an adhesive film online, and it was difficult to obtain an adhesive film with a uniform thickness.

As methods for accurately measuring the thickness of each layer of a multilayer film, optical interference method and infrared absorption method can be mentioned, but as an on-line measurement method, due to requirements such as short measurement time, infrared absorption method is preferably used. However, each layer of this adhesive film is formed of polyimide resins that have different high heat resistance and thermoplastic properties, but have very similar molecular structures. Therefore, the difference in infrared absorption intensity of each layer is converted into thickness In the infrared absorption method, there is a problem that it is difficult to measure the thickness accurately.

In these multilayer films, the dimensional precision of the film thickness of each layer is one of the important specifications. Regarding the method of adjusting the film thickness of each layer of the multilayer film, for example, if it is the coating method of coating the resin solution on the above-mentioned base film, then there is a method of controlling the extrusion amount of the coating die, Or control the gap between the roll coater and the substrate film to adjust the thickness of the coating film; in addition, if it is the extrusion film-making method using the above-mentioned extrusion die, there is a method of embedding in the multi-layer die. A method in which the resin temperature is controlled by a heater in the flange part to adjust the film thickness dimension, and a method in which the film thickness dimension of the film is adjusted by controlling the cross-sectional area of the flow path of each layer with a valve. (for example, patent document 4)

In addition, there is a method of measuring each film thickness dimension with an infrared absorption method or an optical interference method film thickness gauge capable of measuring the film thickness dimension of each layer of a multilayer film, and feeding back the film thickness dimension data to the film thickness adjustment device (for example, patent document 5).

Patent Document 1: Publication No. 2946416

Patent Document 2: JP-A-7-214637

Patent Document 3: JP-A-2003-342390

Patent Document 4: JP-A-2000-127227

Patent Document 5: JP-A-2000-71309

Contents of the invention

The present invention has been accomplished in view of the above-mentioned problems, and provides a polyimide multilayer adhesive film capable of accurately measuring the thickness of each layer by an infrared absorption method, and a method for producing the same. The film thickness deviation of the adhesive film and each layer in the film is small.

The method of controlling the extrusion amount of the above-mentioned coating die, the gap between the roll coater and the base film, the method of adjusting the film thickness with the heater embedded in the flange of the multi-layer die, and the valve A method of controlling the flow path cross-sectional area of each layer to adjust the film thickness dimension. In these methods, it is necessary to measure the film thickness dimension of each layer of the formed multilayer film with high precision, and feed back the film thickness dimension data to each film. In the thickness dimension control device, each film thickness dimension is adjusted and controlled.

In short, there is a problem in the above-mentioned production method that it is difficult to adjust the film thickness of each layer of a continuously produced multilayer film in approximately real time. For example, although there are methods of cutting out a multilayer film for sampling, observing and measuring the cross section with a microscope, etc., it is not possible to feed back the measured data to the film production process in almost real time. In order to adjust the film thickness of the continuously produced multilayer film approximately in real time, it is necessary to measure the film thickness dimension of each film of the multilayer film online with high precision. However, it has been extremely difficult to measure the film thickness of each layer of a multilayer film on-line with high precision.

For example, using a contact-type direct-reading thickness gauge as a way to install a film thickness measuring device online, although the total film thickness of a multilayer film can be measured, the film thickness of each layer cannot be measured theoretically.

On the other hand, with the method described in Patent Document 2, there is a problem that the film thickness dimension of each layer cannot be accurately measured in a multilayer film in which films of materials having the same infrared absorption wavelength and refractive index are laminated. In particular, in the case of a multilayer film mainly made of a polyimide resin, each layer is formed of a polyimide resin having a very similar molecular structure although its high heat resistance and thermoplasticity are different. There is no characteristic infrared absorption wavelength in each layer, and it is difficult to accurately measure the film thickness for the infrared absorption method that uses the difference in the infrared absorption wavelength and the difference in the absorption amount to analyze each layer and convert the film thickness. Furthermore, it is impossible to feed back to the film thickness control device in the film forming process in almost real time, and there is a problem that a high-precision multilayer film with stable film thickness and dimension cannot be produced.

The inventors of the present invention conducted intensive studies in view of the above-mentioned problems, and as a result independently found that an infrared absorption type film thickness gauge can accurately measure the film thickness dimensions of each layer. And the film thickness control system of the film forming process that stabilizes the film thickness dimension. The present invention has been accomplished by solving the above-mentioned problems by the following novel manufacturing method of a multilayer film.

That is, the present invention relates to an adhesive film having a highly heat-resistant polyimide layer and an adhesive layer containing thermoplastic polyimide formed on at least one surface of the highly heat-resistant polyimide layer, It is characterized in that either one of the highly heat-resistant polyimide layer or the adhesive layer contains a polyimide resin containing a functional group exhibiting a characteristic infrared absorption wavelength as a main component. It also relates to the aforementioned adhesive film, and a preferred embodiment thereof is characterized in that the functional group exhibiting a characteristic infrared absorption wavelength is a methyl group, a sulfon group, or a fluoromethyl group.

Furthermore, it relates to the above-mentioned adhesive film, and its preferred embodiment is characterized in that the adhesive film is laminated with a thermoplastic polyimide layer on at least one side of a high heat-resistant polyimide layer by a co-extrusion-cast coating method. Amine adhesive layer to manufacture.

More specifically, 1) a method for producing a polyimide multilayer film, which is a method for producing at least two or more layers of a polyimide resin-containing multilayer film, which is characterized in that it includes the following steps: A process for producing a multilayer film, wherein at least one or more layers of the multilayer film is a layer mainly composed of a polyimide resin containing a functional group exhibiting a characteristic infrared absorption wavelength; irradiating infrared rays in the thickness direction of the film to The process of measuring the distribution of infrared absorption wavelengths and calculating the film thickness of each layer from the infrared absorption in the characteristic wavelength range of each layer; feeding back the calculated film thickness data to the production process of the multilayer film, in the production process A process of applying an operation to adjust the film thickness of each layer.

2) The method for producing a polyimide multilayer adhesive film according to 1), wherein the multilayer film is composed of a layer containing a high heat-resistant polyimide resin and a layer containing a thermoplastic polyimide A layer of resin is formed.

3) The method for producing a polyimide multilayer adhesive film according to 2), wherein the structure of the multilayer film is that, on both sides of a layer containing a highly heat-resistant polyimide resin, a A layer containing thermoplastic resin polyimide resin.

4) The method for producing a polyimide multilayer adhesive film according to 1) to 3), wherein the functional group exhibiting a characteristic infrared absorption wavelength is selected from the group consisting of methyl, sulfo, and fluoromethyl more than one functional group.

5) The method for producing a polyimide multilayer adhesive film according to 1) to 4), wherein, in the production step of the multilayer film, polyimide having a functional group exhibiting a characteristic infrared absorption wavelength A solution of imine resin or its precursor is used to form a film by co-extrusion-cast coating film forming method.

6) The method for producing a polyimide multilayer adhesive film according to 1) to 5), wherein, in the production process of the above-mentioned multilayer film, in the polyimide-containing resin containing at least one layer The film surface of the layer is coated with a solution containing polyamic acid or polyimide resin, heated and dried to form a film.

According to the present invention, it is possible to provide an adhesive film capable of accurately measuring the thickness of each layer by an infrared absorption method.

That is, the manufacture of the polyimide multilayer film of the present invention is to form a film with a polyimide resin layer having a characteristic infrared absorption wavelength on the polyimide film constituting the multilayer, and the subsequent film In the thickness measurement process, infrared rays are irradiated in the thickness direction of the multilayer film, the distribution of the infrared absorption wavelengths passed is measured, and the film thickness dimensions of each layer are calculated from the infrared absorption amounts in the characteristic wavelength ranges of each layer, and the obtained The film thickness data of each layer is fed back to the film forming process to control and adjust the film thickness of each layer. Therefore, it is possible to manufacture a polyimide multilayer film with uniform film thickness and excellent continuous productivity.

Embodiments of the present invention will be described below.

The method for producing a polyimide multilayer film used in the present invention is a method for producing at least two or more layers of a multilayer film containing a polyimide resin, and is characterized in that it includes the following steps: a multilayer film In the production process of the multilayer film, at least one or more layers of the multilayer film are layers mainly composed of polyimide resin containing functional groups showing characteristic infrared absorption wavelengths; infrared rays are irradiated in the thickness direction of the film to measure infrared rays The distribution of absorption wavelengths, the process of calculating the film thickness of each layer from the infrared absorption of the characteristic wavelength range of each layer; the calculated film thickness data is fed back to the production process of the multilayer film, and adjustments are made in the production process The operation process of the film thickness of each layer.

The process of producing a multilayer film in which at least one layer is a layer mainly composed of a polyimide resin containing a functional group exhibiting a characteristic infrared absorption wavelength will be described.

In the present invention, as will be described later, infrared rays are irradiated in the thickness direction of the film to measure the distribution of the absorption wavelength of infrared rays, and the film thickness dimension of each layer is calculated from the infrared absorption amount in the characteristic wavelength range of each layer. In the constitution of the layer film, it is important that any layer contains a polyimide resin having a functional group exhibiting a characteristic infrared wavelength in an amount of the main component. Depending on which layer of the multilayer film you want to measure the film thickness of, you can decide which layer to use polyimide resin having a functional group that exhibits a characteristic infrared absorption wavelength, or what combination to choose as the one that exhibits a characteristic infrared absorption wavelength. wavelength functional groups. Hereinafter, a specific example will be given to describe a multilayer film having a high heat-resistant polyimide layer and a thermoplastic polyimide layer formed on at least one surface of the high heat-resistant polyimide layer. The composition of the adhesive layer of amine.

Description of drawings

FIG. 1 : Embodiment of the manufacturing method of the polyimide multilayer adhesive film of the present invention.

FIG. 2 : Another embodiment of the method for producing a polyimide multilayer adhesive film of the present invention.

Figure 3: Embodiment of the polyimide multilayer extrusion die of the present invention.

Symbol Description

10: Polyimide multilayer adhesive film

21: Support

22: drying oven

23: Stenter furnace

24: Winding machine

25: Sending out machine

31: Film thickness gauge with infrared absorption method

32: Control system

33: Film thickness adjustment device

40: multi-layer extrusion die

41: Injection Road

42: Manifold

43: Heater

44: flow path

45: Confluence

46: Flow path for refrigerant

47: Flange width adjustment mechanism by motor

51: coating die

Detailed ways

The method for producing a polyimide multilayer adhesive film used in the present invention is a multilayer adhesive film containing at least two or more layers of polyimide resin and a method for producing the same.

The polyimide multilayer adhesive film of the present invention has a highly heat-resistant polyimide layer and an adhesive layer containing thermoplastic polyimide formed on at least one surface of the highly heat-resistant polyimide layer. The layer is characterized in that either one of the highly heat-resistant polyimide layer or the adhesive layer contains a polyimide resin containing a functional group exhibiting a characteristic infrared absorption wavelength as a main component.

By making either the high heat-resistant polyimide layer or the adhesive layer a polyimide resin containing a functional group exhibiting a characteristic infrared absorption wavelength as the main component, the thickness measurement device of the infrared absorption method multilayer film The S/N ratio increases, and the film thickness of each layer can be measured with high precision.

The features of the embodiments of the present invention will be further described.

The method for producing a polyimide multilayer adhesive film used in the present invention is a method for producing a multilayer film containing at least two layers of polyimide resin, and is characterized in that it includes the following steps: A process for producing a multilayer film, wherein at least one or more layers of the multilayer film is a layer mainly composed of a polyimide resin containing a functional group exhibiting a characteristic infrared absorption wavelength; irradiating infrared rays in the thickness direction of the film to The process of measuring the distribution of infrared absorption wavelengths and calculating the film thickness of each layer from the infrared absorption in the characteristic wavelength range of each layer; feeding back the calculated film thickness data to the production process of the multilayer film, in the production process A process of applying an operation to adjust the film thickness of each layer.

The process of producing a multilayer film in which at least one layer is a layer mainly composed of a polyimide resin containing a functional group exhibiting a characteristic infrared absorption wavelength will be described.

In the present invention, as will be described later, infrared rays are irradiated in the thickness direction of the film to measure the distribution of the absorption wavelength of infrared rays, and the film thickness dimension of each layer is calculated from the infrared absorption amount in the characteristic wavelength range of each layer. In the constitution of the layer film, it is important that any layer contains a polyimide resin having a functional group exhibiting a characteristic infrared wavelength in an amount of the main component. Depending on which layer of the multilayer film you want to measure the film thickness of, you can decide which layer to use polyimide resin with a functional group that exhibits a characteristic infrared absorption wavelength, or what combination to choose as a characteristic infrared ray display. A functional group that absorbs wavelengths. Hereinafter, a specific example will be given to describe a multilayer film having a high heat-resistant polyimide layer and a thermoplastic polyimide layer formed on at least one surface of the high heat-resistant polyimide layer. The composition of the adhesive layer of amine.

<High heat resistant polyimide layer>

The molecular structure and film thickness of the highly heat-resistant polyimide layer in the present invention are not particularly limited as long as it contains 90% by weight or more of non-thermoplastic polyimide resin. The non-thermoplastic polyimide used in the high heat-resistant polyimide layer is manufactured using polyamic acid as a precursor. The production method of polyamic acid can use all known methods, usually, by the following method: aromatic tetracarboxylic dianhydride and aromatic diamine are dissolved in the organic solvent with the amount of substantially equimolar, in controlled Stirring is carried out under temperature conditions until the polymerization of the above-mentioned acid dianhydride and diamine is completed. These polyamic acid solutions are usually obtained at a concentration of 5 to 35 wt%, preferably 10 to 30 wt%. When the concentration is within this range, an appropriate molecular weight and solution viscosity are obtained.

As the polymerization method, all known methods and methods obtained by combining them can be used. The polymerization method in the polymerization of polyamic acid is characterized by the addition order of the monomers, and various physical properties of the obtained polyimide can be controlled by controlling the addition order of the monomers. Therefore, any method for adding a monomer can be used for the polymerization of the polyamic acid of the present invention. As a representative polymerization method, the following methods can be mentioned. That is, methods such as the following:

1) A method in which an aromatic diamine is dissolved in an organic polar solvent and reacted with substantially equimolar aromatic tetracarboxylic dianhydride to polymerize.

2) Reaction of aromatic tetracarboxylic dianhydride and an aromatic diamine compound having an excessively small molar amount relative to it in an organic polar solvent to obtain a prepolymer having acid anhydride groups at both terminals. Next, the method of superposing|polymerizing using an aromatic diamine compound so that an aromatic tetracarboxylic dianhydride and an aromatic diamine compound may become substantially equimolar in the whole process.

3) Aromatic tetracarboxylic dianhydride and an aromatic diamine compound in an excess molar amount are reacted in an organic polar solvent to obtain a prepolymer having amino groups at both terminals. Next, after adding an aromatic diamine compound thereto, the aromatic tetracarboxylic dianhydride and the aromatic diamine compound are substantially equimolar in the entire process, and then polymerized using the aromatic tetracarboxylic dianhydride .

4) After dissolving and/or dispersing an aromatic tetracarboxylic dianhydride in an organic polar solvent, there is a method of polymerizing using an aromatic diamine compound in a substantially equimolar manner.

5) A method of polymerizing by reacting a mixture of substantially equimolar aromatic tetracarboxylic dianhydrides and aromatic diamines in an organic polar solvent.

These methods can be used alone or partially in combination.

In the present invention, polyamic acid obtained by any of the above-mentioned polymerization methods can be used, and the polymerization method is not particularly limited.

In the present invention, it is preferable to employ a polymerization method for obtaining a prepolymer using a diamine component having a rigid structure described later. By using this method, it tends to be easy to obtain a polyimide film having a high modulus of elasticity and a small coefficient of hygroscopic expansion. In this method, the molar ratio of the diamine having a rigid structure to the acid dianhydride used in preparing the prepolymer is preferably 100:70 to 100:99 or 70:100 to 99:100, more preferably 100:75 to 100 :90 or 75:100～90:100. If the ratio is lower than the above range, it is difficult to obtain the effect of improving the modulus of elasticity and the hygroscopic expansion coefficient; if it is higher than the above range, the linear expansion coefficient becomes too small, and disadvantages such as reduced elongation may occur.

Here, the materials used for the polyamic acid composition of this invention are demonstrated.

Suitable tetracarboxylic dianhydrides that can be used in the present invention include pyromellitic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic anhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride anhydride, 4,4'-oxyphthalic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bis(3 , 4-dicarboxyphenyl) propane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dihydride anhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)ethane dianhydride, oxygen diphthalic dianhydride, bis(3,4-dicarboxyphenyl) base) sulfone dianhydride, p-phenylene bis(trimellitic monoester anhydride), ethylene bis(trimellitic monoester anhydride), bisphenol A bis(trimellitic monoester anhydride) and their The analogues of these compounds can be preferably used alone or as a mixture in any proportion.

Among these acid dianhydrides, it is particularly preferable to use pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 4,4'-oxyphthalic dianhydride, At least one of 3,3',4,4'-biphenyltetracarboxylic dianhydrides.

In addition, among these acid dianhydrides, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 4,4'-oxyphthalic dianhydride, 3,3',4, When at least one of 4'-biphenyltetracarboxylic dianhydrides is used, the preferred usage amount is 60 mol% or less, preferably 55 mol% or less, more preferably 50 mol% or less of the total acid dianhydrides. When using 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 4,4'-oxyphthalic dianhydride, 3,3',4,4'-biphenyltetracarboxylic When at least one of the anhydrides is used, if the usage amount exceeds this range, the glass transition temperature of the polyimide film becomes too low, or the storage modulus of elasticity during heating becomes too low, making it difficult to form the film itself. Therefore, it is not preferable.

Moreover, when pyromellitic dianhydride is used, the usage-amount is preferable 40-100 mol%, More preferably, it is 45-100 mol%, Especially preferably, it is 50-100 mol%. By using pyromellitic dianhydride in this range, it becomes easy to keep the glass transition temperature and the storage modulus of elasticity during heat in an appropriate range during use or film production.

For the polyamic acid composition which is the precursor of the non-thermoplastic polyimide according to the present invention, suitable diamines that can be used include 4,4'-diaminodiphenylpropane, 4,4 '-Diaminodiphenylmethane, benzidine, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 3,3'-di Methoxybenzidine, 2,2'-dimethoxybenzidine, 4,4'-diaminodiphenylsulfide, 3,3'-diaminodiphenylsulfone, 4,4'-diamino Diphenylsulfone, 4,4'-oxydiphenylamine, 3,3'-oxydiphenylamine, 3,4'-oxydiphenylamine, 1,5-diaminonaphthalene, 4,4'-diaminodiphenyl Diethylsilane, 4,4'-diaminodiphenylsilane, 4,4'-diaminodiphenylethylphosphine oxide, 4,4'-diaminodiphenyl-N-methylamine, 4 , 4'-diaminodiphenyl-N-phenylamine, 1,4-diaminobenzene (p-phenylenediamine), 1,3-diaminobenzene, 1,2-diaminobenzene, bis{ 4-(4-aminophenoxy)phenyl}sulfone, bis{4-(4-aminophenoxy)phenyl}propane, bis{4-(3-aminophenoxy)phenyl}sulfone, 4 , 4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 3,3'- Diaminobenzophenone, 4,4'-diaminobenzophenone and their analogues.

As the diamine component, a diamine having a rigid structure and an amine having a flexible structure may be used in combination. In this case, the preferred use ratio is 80/20 to 20/80, further 70/30 to 30/70 in terms of molar ratio, especially It is 60/40～30/70. If the usage ratio of the diamine of the rigid structure exceeds the above-mentioned range, the elongation of the obtained film tends to be small, and if it is lower than this range, the glass transition temperature becomes too low, or the storage modulus of elasticity when heated If it becomes too low, there may be disadvantages such as difficulty in film formation.

In the present invention, the diamine having a rigid structure is represented by the general formula (1).

NH ₂ -R ₂ -NH ₂

General formula (1)

R in the general formula (1) is a group selected from the divalent aromatic groups represented by the general formula group (1); R in the general formula group ( ₁ ) can be _the same or different, and is selected from Any one of H-, CH ₃ -, -OH, -CF ₃ , -SO ₄ , -COOH, -CO-NH ₂ , Cl-, Br-, F- and CH ₃ O-.

Formula group (1)

In addition, the diamine having a flexible structure refers to a diamine having a flexible structure such as an ether group, a sulfo group, a ketone group, or a thioether group. A substance represented by the following general formula (2) is preferable.

通式(2)

Formula (2)

R in general formula (2) _is a group selected from divalent organic groups represented by general formula group (2), R in general formula ( ₂ ) can be the same or different, and is selected from H-, Any one of CH ₃ -, -OH, -CF ₃ , -SO ₄ , -COOH, -CO-NH ₂ , Cl-, Br-, F- and CH ₃ O-.

-O-,

通式组(2)

Formula group (2)

The polyimide film used in the present invention can be obtained by appropriately determining the types and compounding ratios of aromatic acid dianhydride and aromatic diamine within the above range so that a film having desired characteristics can be formed. .

As a preferred solvent for synthesizing polyamic acid, any substance can be used as long as it dissolves polyamic acid, but amide solvents, that is, N, N-dimethylformamide, N, N-di Methylacetamide, N-methyl-2-pyrrolidone and the like are particularly preferably used as N,N-dimethylformamide and N,N-dimethylacetamide.

In addition, fillers may be added in order to improve various properties of the film such as sliding properties, thermal conductivity, electrical conductivity, corona resistance, and loop stiffness. Any filler can be used, but preferred examples include silica, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, mica, and the like.

Since the particle size of the filler is determined according to the properties of the film to be modified and the type of filler to be added, there is no particular limitation. Generally speaking, the average particle size is 0.05-100 μm, preferably 0.1-75 μm, more preferably 0.1-50 μm, Particularly preferably, it is 0.1 to 25 μm. If the particle size is below this range, the effect of modification will be difficult to exhibit; if it exceeds this range, the surface properties may be greatly impaired or the mechanical properties may be greatly reduced. In addition, the number of fillers to be added is also determined according to the properties of the membrane to be modified and the particle size of the filler, so there is no particular limitation. Generally, the addition amount of a filler is 0.01-100 weight part with respect to 100 weight part of polyimides, Preferably it is 0.01-90 weight part, More preferably, it is 0.02-80 weight part. If the amount of the filler added is lower than this range, the modification effect brought by the filler is difficult to manifest; if it exceeds this range, the mechanical properties of the film may be greatly damaged. Fillers can be added in any of the following ways:

1. The method of adding to the polymerization reaction solution before or during the polymerization;

2. After the polymerization is completed, use a three-roll machine to mix the filler;

3. A method of preparing a dispersion liquid containing a filler, mixing it in a polyamic acid organic solvent solution, and the like. The method of mixing the filler-containing dispersion liquid with the polyamic acid solution, especially the method of mixing immediately before film formation, is preferable because the pollution of the production line due to the filler is the least. When preparing a filler-containing dispersion liquid, it is preferable to use the same solvent as the polymerization solvent of the polyamic acid. In addition, in order to disperse the filler well or to stabilize the dispersed state, a dispersant, a thickener, and the like may be used within a range that does not affect film properties.

The thus obtained solution having a non-thermoplastic polyimide precursor is also referred to as a solution containing a highly heat-resistant polyimide precursor.

<Thermoplastic polyimide layer>

The content, molecular structure, and film thickness of the thermoplastic polyimide resin contained in the layer are not particularly limited as long as the thermoplastic polyimide layer according to the present invention exhibits useful adhesive force by a lamination method. However, in order to exhibit useful adhesive force, it is preferable to substantially contain 50 wt% or more of the thermoplastic polyimide resin.

As the thermoplastic polyimide contained in the thermoplastic polyimide layer, thermoplastic polyimide, thermoplastic polyamideimide, thermoplastic polyetherimide, thermoplastic polyesterimide, etc. can be preferably used. Among them, thermoplastic polyester imide is particularly preferably used from the viewpoint of low hygroscopicity.

The thermoplastic polyimide contained in the thermoplastic polyimide layer of this invention can be obtained by the conversion reaction of the precursor polyamic acid from it. As a method for producing the polyamic acid, any known method can be used in the same manner as the precursor of the highly heat-resistant polyimide layer.

In addition, lamination can be performed with existing equipment, and the thermoplastic polyimide in the present invention preferably has a vitrification temperature of 150 to 300° C. temperature (Tg). Tg can be obtained from the inflection point value of the storage elastic modulus measured with a dynamic viscoelasticity measuring device (DMA).

The polyamic acid which is the precursor of the thermoplastic polyimide used in the present invention is also not particularly limited, and any known polyamic acid can be used. Also about manufacture of a polyamic-acid solution, the said raw material, the said manufacture conditions, etc. can be used in the same manner.

Various properties of thermoplastic polyimide can be adjusted by various combinations of raw materials used. In general, the higher the ratio of diamines with a rigid structure, the higher the glass transition temperature and/or the storage elastic modulus when heated. If it becomes large, adhesiveness and processability will become low, and it is unpreferable. The diamine ratio of the rigid structure is preferably 40 mol% or less, more preferably 30 mol% or less, particularly preferably 20 mol% or less.

Specific examples of preferable thermoplastic polyimide resins include those obtained by polymerizing acid dianhydrides including biphenyltetracarboxylic dianhydrides and diamines having aminophenoxy groups.

Further, in order to control the properties of the adhesive film according to the present invention, if necessary, inorganic or organic fillers may be added, and further other resins may be added.

<Combination of polyimide molecules in each layer>

In the present invention, either the highly heat-resistant polyimide layer or the adhesive layer must contain a polyimide resin containing a functional group exhibiting a characteristic infrared absorption wavelength as a main component. In the case of an adhesive layer on both sides of the high heat-resistant polyimide layer, the adhesive layer can be only on one side, or only on the high heat-resistant polyimide layer, or on each layer separately to contain A polyimide resin with a functional group that absorbs wavelengths characteristic of infrared rays is the main component. In the present invention, the functional group exhibiting a characteristic infrared absorption wavelength is any functional group as long as it has an absorption amount that can be clearly detected by a film thickness measuring device when irradiated with infrared rays having a wavenumber of 400 cm-1 to 4000 cm-1. It is not particularly limited, but in consideration of the properties of the finally obtained adhesive film, any one of a methyl group, a sulfo group, and a fluoromethyl group is particularly preferable.

As a method of including a functional group exhibiting a characteristic infrared absorption wavelength in a polyimide resin, the following can be exemplified:

1) A method of using a monomer having the functional group as a monomer forming a polyimide resin;

2) a method for grafting it to polyimide resin or its precursor polyamic acid;

However, in consideration of production cost, the method of 1) is particularly preferably used. When the method of 1) is used, the monomers preferably used can be exemplified as follows. Examples of acid dianhydrides include 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, bis(3,4-dicarboxyphenyl) Carboxyphenyl)sulfone dianhydride, 5,5'-2,2,2-trifluoro-1-(trifluoromethyl)ethylene-bis-1,3-isobenzofurandione; as diamine , exemplified by 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]sulfone, 4,4'- Diamino-2,2'-dimethylbiphenyl, 4,4'-diamino-2,2'-hexafluorodimethylbiphenyl and the like.

For a polyimide resin containing a functional group exhibiting a characteristic infrared absorption wavelength, it is preferable to use monomeric diamine or acid diamine from the viewpoint that the S/N ratio can be ensured and the film thickness of each layer can be measured with high precision. Based on the anhydride, it contains 50 mol% or more, preferably 70 mol% or more, more preferably 80 mol% or more of functional groups exhibiting characteristic infrared absorption wavelengths.

In addition, having a polyimide resin having a functional group exhibiting a characteristic infrared absorption wavelength as a main component means containing 90% by weight or more of a polyimide resin having a functional group exhibiting a characteristic infrared absorption wavelength.

<Manufacture of polyimide multilayer adhesive film>

Although an example of the method of obtaining the polyimide multilayer adhesive film of this invention is demonstrated below, it is not limited to this.

The method for obtaining the adhesive film of the present invention comprises the following steps: using a solution containing polyimide resin and/or two or more solutions containing its precursor to form several layers of liquid film on the support, Thereafter, drying and imidization are performed. The method of forming several layers of liquid film on the support can use the following methods: the method of using a multi-layer die, the method of using a sliding die, and the method of using a plurality of single-layer dies, combining a single-layer die and spraying, A conventionally known method such as a method of combining gravure coating. However, in consideration of productivity, maintainability, etc., the method of using a multilayer die is particularly preferable. Hereinafter, a multi-layer die is taken as an example, which is shown in FIG. 1 for description.

First, a solution containing a highly heat-resistant polyimide precursor, a solution containing a thermoplastic polyimide, or a solution containing a thermoplastic polyimide precursor is supplied to a multilayer die 40 having two or more layers. , the two solutions are extruded as liquid films of several layers 10 from the extrusion port of the above-mentioned multilayer die 40 . Then, the liquid film of several layers 10 extruded from the multilayer die 40 is flow-cast on a smooth support 21 (an endless belt in Fig. 1), so that the liquid film of several layers 10 on the above-mentioned support 21 At least a part of the solvent is volatilized in the drying furnace 22, so that the self-supporting multilayer film 10 can be obtained. Furthermore, the multilayer film 10 is peeled from the above-mentioned support 21, and finally, the multilayer film 10 is sufficiently heat-treated at a high temperature (250-600° C.) in a tenter furnace 23 to substantially remove the solvent, and By performing imidization, the target polyimide multilayer film 10 can be obtained, and it winds up with the winder 24 .

In order to improve the melt fluidity of the adhesive layer in the tenter furnace 23, set the tenter furnace 23 to a low temperature, or shorten the time of passing through the tenter furnace, and also intentionally reduce the imidization rate and/or make the solvent residual.

That is, a solution containing a highly heat-resistant polyimide precursor, a solution containing a thermoplastic polyimide, or a solution containing a thermoplastic polyimide precursor is supplied to a multilayer die having two or more layers, The two solutions were extruded as several-layered liquid films from the extrusion port of the above-mentioned multilayer die. Then, the several layers of liquid films extruded from the multi-layer die are cast on a smooth support, and at least a part of the solvent of the several layers of liquid films on the above support is volatilized, thereby obtaining a self-supporting multilayer film. Furthermore, the multilayer film is peeled from the above-mentioned support, and finally, the multilayer film is sufficiently heat-treated at high temperature (250-600° C.) to substantially remove the solvent and imidize, thereby The target adhesive film can be obtained. In addition, in order to improve the melt fluidity of the adhesive layer, the imidation rate may be intentionally reduced and/or the solvent may remain.

Generally, a polyimide is obtained by the dehydration conversion reaction of the polyamic acid which is the precursor of a polyimide. As a method for carrying out this conversion reaction, two methods, namely, a heat treatment method using only heat and a chemical treatment method using a chemical curing agent, are most widely known. However, chemical treatment is more preferable in consideration of manufacturing efficiency.

For the multi-layer die, there are known multi-manifold methods, feed block methods, a mixture of both, and any of them can be used.

As the above-mentioned support, in consideration of the use of the adhesive film to be finally obtained, it is preferably as smooth as possible; further, in consideration of productivity, it is preferably in the form of an endless belt or a roll.

Here, the chemical curing agent refers to a substance containing a dehydrating agent and a catalyst. The dehydrating agent mentioned here refers to the dehydrating ring-closing agent of polyamic acid, as its main component, can preferably use aliphatic acid anhydride, aromatic acid anhydride, N, N,-dialkylcarbodiimide, lower aliphatic Halides, halogenated lower aliphatic anhydrides, arylsulfonic acid dihalides, thionyl halides, or mixtures of two or more of these substances. Among them, especially aliphatic acid anhydrides and aromatic acid anhydrides work well. In addition, the catalyst is a component that has the effect of accelerating the dehydration and ring closure of the polyamic acid by the curing agent, and for example, aliphatic tertiary amines, aromatic tertiary amines, and heterocyclic tertiary amines can be used. Among them, nitrogen-containing heterocyclic compounds such as imidazole, benzimidazole, isoquinoline, quinoline, or β-picoline are preferable. Furthermore, the introduction of an organic polar solvent into a solution containing a dehydrating agent and a catalyst can be appropriately selected.

There are no particular limitations on the method of volatilizing the solvent in the solution of the precursor solution of the highly heat-resistant polyimide, the solution containing the thermoplastic polyimide, or the solution containing the precursor of the thermoplastic polyimide. The method of blowing is the easiest method. If the heating temperature is too high, the solvent will evaporate rapidly, and since traces of this evaporation are the main cause of microscopic defects in the final adhesive film, it is preferable that the solvent used has a boiling point of less than +50°C.

The imidization time is not absolutely limited as long as there is sufficient time for imidization and drying to be basically completed, but generally, it is appropriately set to about 1 to 600 seconds.

The tension applied at the time of imidization is preferably 1 kg/m to 15 kg/m, particularly preferably 5 kg/m to 10 kg/m. If the tension is less than the above range, the film may slack or meander during conveyance, and wrinkles may be mixed during winding, causing problems such as uneven winding. On the contrary, if the value exceeds the above range, the dimensional characteristics of the obtained flexible metal-bonded laminate will be deteriorated due to heating at a high temperature under a state of strong tension.

Next, the process of irradiating infrared rays in the thickness direction of the obtained multilayer film, measuring the distribution of infrared absorption wavelengths, and calculating the film thickness dimension of each layer from the infrared absorption amount in the characteristic wavelength range of each layer will be described.

The principle of the film thickness measuring device that can be used in this process is to irradiate infrared rays having a wavelength of 400 cm ^-1 to 4000 cm ^-1 perpendicularly to the thickness direction of the film to be measured by using an infrared absorption method film thickness measuring device. The difference in the absorption amount of the transmitted infrared rays with respect to the film thickness dimension is measured at a wavelength unique to the substance, and the film thickness is calculated from the difference in the absorption amount.

Therefore, in the present invention, since at least one layer or more of the multilayer film contains a polyimide resin having a functional group exhibiting a characteristic infrared absorption wavelength as a main component, the infrared rays having a characteristic wavelength of the polyimide resin The absorption amount can calculate the film thickness of the entire multilayer film, and the film thickness of the polyimide resin layer can be calculated from the infrared absorption amount of the polyimide resin layer containing a functional group exhibiting a characteristic infrared absorption wavelength.

For example, in the case of the following polyimide three-layer film, if the film thickness is measured with the above-mentioned infrared absorption method film thickness gauge, the film thickness dimension and the adhesion of the polyimide three-layer film as a whole can be measured. Each film thickness size of the layer; the multilayer film of the polyimide three-layer film is formed by a high heat-resistant polyimide layer and on both sides of the high heat-resistant polyimide layer, containing An adhesive layer composed of thermoplastic polyimide, wherein one of the adhesive layers contains a polyimide resin containing a functional group exhibiting a characteristic infrared absorption wavelength as a main component, and the other adhesive layer contains a polyimide resin containing Another main component is a polyimide resin having a functional group exhibiting a characteristic infrared absorption wavelength. Next, by subtracting the respective film thicknesses of the adhesive layer from the film thicknesses of the entire polyimide three-layer film, it is clear that the film thicknesses of the highly heat-resistant polyimide layer can be calculated. In addition, the film thickness dimension of the required adhesive layer can be the sum of the film thickness dimensions of the adhesive layer on both sides of the composition, or when only the film thickness dimension of the high heat-resistant polyimide layer is required, as long as It is only necessary to contain a functional group exhibiting a characteristic infrared absorption wavelength in either the adhesive layer or the highly heat-resistant polyimide layer.

As far as the installation location of the film thickness meter 31 of the infrared absorption method is concerned, it can be installed as long as the multilayer film can be measured. If the amount of heat shrinkage is eliminated in advance, it can be installed near the extrusion port of the multilayer die 40 or in the drying area. Near the exit of the furnace 22, but from the viewpoint of measuring the final film thickness with high precision, it is better to finish the imidization in the tenter furnace 23 and measure the multilayer film 10 cooled to about room temperature. Between the tenter furnace 23 and the winder 24 .

Next, a process of feeding back the calculated film thickness dimensional data to the production process of the multilayer film and applying an operation to adjust the film thickness of each layer in the production process will be described.

The film thickness size data of each layer measured by the film thickness gauge 31 and calculated by the film thickness control system 32 are fed back to the film thickness size control device 33 assembled in the multilayer die 40, so that when the film thickness deviates from the desired When dimensioning, control the desired film thickness.

With regard to the film thickness size control device 33 that can be adopted in the present invention, various film thickness size control devices that can continuously control the film thickness by feeding back the film thickness size data of each layer measured by the above-mentioned film thickness gauge 31 can be used. device33.

The specific film thickness adjustment device of the present invention will be described by taking the multi-layer die as an example. The multilayer die used is not particularly limited to the multilayer die used in the present invention as long as the polyimide multilayer film is produced from a solution containing at least two or more polyimide resins or their precursors. layers and forms.

Hereinafter, a specific example of the multi-manifold type multilayer die used in the present invention will be described with reference to FIG. 3 .

In the present invention, heating elements are used to adjust the film thickness of each layer of the multilayer film. That is, since the flow path inside the die after the manifold in co-extrusion film production is a very thin plate-shaped space, a large flow resistance is generated for the fluid passing there. Therefore, if the viscosity of the fluid changes, the fluid resistance changes, and as a result, the extrusion amount of the fluid changes, and as a result, the film thickness dimension also changes.

First, solutions A, B, and C (hereinafter simply referred to as solutions A, B, and C) containing polyimide resin or its precursor are injected into the die through injection channels 41a, 41b, and 41c, respectively. After each polyimide resin solution is injected from the injection channel 41, it spreads in the width direction at the manifolds 42a, 42b, and 42c, and flows into the flow channel 44 in this state. Generally speaking, the flow path 44 with a thickness of about several tens to several hundreds of μm generates a large fluid resistance to the solution containing polyimide resin or its precursor, so if the viscosity of the solution is lowered, the solution will flow increases. For example, when the heating element 43a heats the solution A flowing into the flow path 44a and the vicinity of the flow path 44a, the viscosity of the polyimide resin solution A decreases, resulting in an increase in the extrusion rate at the flow path 44a. When the extrusion amount increases, the ratio of the solution A to the polyimide resin solutions B and C after the confluence point 45 increases, and the film thickness of the polyimide resin solution A in the liquid film increases. Likewise, the film thickness of the solution C flowing into the flow path 44c can be controlled by the heating element 43c.

In addition, it is the flange adjustment mechanism 47 that adjusts the overall film thickness of the multilayer film. By adjusting the film thicknesses of the polyimide resin solutions A and C with the heating elements 43a and 43c, the flange adjustment mechanism 47 is used to adjust the overall film thickness. Thick, since the film thickness ratio of solutions A and C does not change, it is also possible to adjust the film thickness of polyimide resin solution B.

The modes that can be adopted in the flange adjustment mechanism 47 have the following modes: physically expand or reduce the mechanism of the flange width of the die, fix one end of the heating element to the die, and expand the heating element so that the flange of the die can be adjusted. A moving heat pipe type or a method in which the die flange can be moved by a motor or the like.

The heating element used in the present invention can be used without limitation as long as it is an industrial or generally available method. In particular, a type in which electric current is passed through a resistance element of metal, carbon, or an inorganic compound for heating is preferable because it is easy to handle and has good responsiveness. In addition, an electromagnetic induction heating element is more preferable because the responsiveness is further improved.

The disposition position of heating element in the present invention, because the thickness of each layer of multilayer film is controlled separately, therefore heating element is arranged in the position before the solution confluence of various containing polyimide resin or its precursor certainly is important . Also, by arranging heating elements continuously in the width direction with respect to the flow path extending in the width direction, it is also possible to control the film thickness dimension at a specific position in the width direction of each film layer.

However, at this time, in order to obtain data for controlling the pitch of the film thickness gauges in the width direction, it is necessary to either install several film thickness gauges in the width direction or place one film thickness gauge in the width direction. The mechanism that measures the film thickness distribution in the width direction by moving up and down can produce high-quality multilayer films by stabilizing the flow direction of the film and the film thickness distribution in the width direction uniformly.

When the heating elements are arranged consecutively, the intervals of the heating elements are not particularly limited as long as sufficient intervals necessary for control are selected. Generally speaking, if the space between the heating elements is too close, it may cause mutual interference. Therefore, it is preferable to arrange the heating elements at intervals of 5 to 50 mm. Since the balance of film thickness uniformity and mutual interference is the best, it is more preferable 7 ~ 20mm interval.

In the present invention, holes are provided inside the multilayer die to allow the refrigerant to circulate, and the multilayer die can also be effectively cooled. Generally speaking, the precursor of polyimide resin has the characteristic that the intramolecular dehydration reaction takes place and solidifies at high temperature, and the multi-layer die of the present invention is provided with the film thickness adjustment mechanism that utilizes heating element to have die temperature slowly. As a result, the resin in the flow path in the die is cured and adhered to deteriorate film formability, or cause the cured product to mix into the film.

As a cooling device, there are a method of circulating a refrigerant in the above-mentioned multi-layer die, and a method of winding a tube outside the multi-layer die to allow the refrigerant to flow inside. In addition, it is also possible to blow air flow on the outside of the multi-layer die, and in order to improve the cooling effect, it is also possible to install cooling fins.

The temperature of the cooled multilayer die is preferably below room temperature, more preferably below 10°C, most preferably below 0°C. However, if the temperature is too low, the viscosity of the polyimide compound varnish becomes too high and handling becomes difficult, so it is preferably -15°C or higher, more preferably -10°C or higher.

Next, a method for forming a film by applying a solution containing polyamic acid or polyimide resin on the surface of a film containing at least one layer containing polyimide resin, heating, and drying is described. Methods. A film containing at least one layer of high heat-resistant polyimide resin is used as a core layer, and a solution containing thermoplastic polyimide or a solution containing thermoplastic polyimide is coated on both sides by coating. The solution of the amine precursor is used as a cover layer to obtain a multilayer polyimide multilayer film. This manufacturing method is shown in FIG. 2 and demonstrated.

First, the high heat-resistant polyimide film obtained by forming a single-layer or multi-layer film is sent out as a core layer into the coating device by the sending device 25, and the film containing A solution of thermoplastic polyimide or a solution containing a precursor of thermoplastic polyimide is coated on both sides of the core layer with cover layers. Next, imidization is performed while volatilizing the solvent of the liquid film of the cover layer in the drying furnace 22 to obtain the target polyimide multilayer film 10 , which is wound up by the winder 24 .

As the coating method, other than the above-mentioned coating die, a roll coating method, a gravure roll method, a spray coating method, etc. are known, and any of them may be used.

The installation location of the film thickness gauge 31 of the infrared absorption method is the same as that of the above-mentioned multi-layer die method, and is preferably installed between the drying oven 22 and the winding machine 24 .

The film thickness control method of the coating method can be controlled by the method of controlling the coating film thickness in the following way: using the pump that supplies the resin to control the extrusion amount of the coating die, or the coating method using a roll coater. Control the gap between the substrate film and the roller coater.

Example

Hereinafter, an example of the method of the present invention will be given and described in detail, but the present invention is not limited to this example.

(Synthesis Example 1: Synthesis of polyamic acid as a precursor of highly heat-resistant polyimide compounds)

Add 76.2kg of DMF cooled to 10°C, 3.7kg of p-phenylenediamine (PDA), and slowly add 9.8kg of 3,3',4,4'-biphenyltetracarboxylic acid di Anhydride (BPDA), stirred for 30 minutes. Separately, a solution obtained by dissolving 300 g of BPDA in 2 kg of DMF was prepared, and this was slowly added to the above-mentioned reaction solution while paying attention to the viscosity, followed by stirring. When the viscosity reached 3500 poise, the addition and stirring were stopped to obtain a solution of polyamic acid which is a precursor of a highly heat-resistant polyimide compound.

In this synthesis example, when the thickness of each layer was measured by an infrared absorption method, there was no functional group exhibiting a characteristic infrared absorption wavelength.

(Synthesis Example 2: Synthesis of polyamic acid as a precursor of highly heat-resistant polyimide compounds)

6.9kg of 4,4'-oxydianiline (hereinafter also referred to as ODA), 6.2kg of p-phenylenediamine (hereinafter also referred to as p-PDA), 9.4kg of 2,2-bis[4- (4-Aminophenoxy) phenyl] propane (hereinafter also referred to as BAPP) was dissolved in 239 kg of N, N-dimethylformamide (hereinafter also referred to as DMF) cooled to 10 ° C, and 10.4 kg of Pyromellitic dianhydride (hereinafter also referred to as PMDA) was stirred for 1 hour and dissolved. 20.3 kg of benzophenone tetracarboxylic dianhydride (hereinafter also referred to as BTDA) was added there, and stirred for 1 hour to dissolve it.

The DMF solution of PMDA prepared separately (PMDA:DMF=0.9kg:7.0kg) was slowly added to the above reaction solution, and the addition was stopped when the viscosity reached about 3000 poise. Stirring was performed for 1 hour to obtain a solution of polyamic acid which is a precursor of a highly heat-resistant polyimide compound having a solid content concentration of 18% by weight and a rotational viscosity at 23° C. of 3,500 poise.

In this synthesis example, when the thickness of each layer was measured by an infrared absorption method, the functional group exhibiting a characteristic infrared absorption wavelength was a methyl group derived from BAPP.

(Synthesis Example 3: Synthesis of Polyamic Acid as a Precursor of Thermoplastic Polyimide Compounds)

Add 78kg of DMF cooled to 10°C, 11.56kg of 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPS), and slowly add 7.87kg of 3 , 3',4,4'-Biphenyltetracarboxylic dianhydride (BPDA). Next, 380 g of ethylene bis(trimellitic acid monoester anhydride) (TMEG) was added, and it stirred for 30 minutes. Separately, a solution obtained by dissolving 300 g of TMEG in 3 kg of DMF was prepared, and this was slowly added to the above reaction solution while paying attention to the viscosity, followed by stirring. When the viscosity reached 3000 poise, the addition and stirring were stopped to obtain a solution of polyamic acid which is a precursor of a thermoplastic polyimide compound.

In this synthesis example, when the thickness of each layer was measured by an infrared absorption method, the functional group exhibiting a characteristic infrared absorption wavelength was a methyl group derived from BAPP.

(Synthesis Example 4: Synthesis of Polyamic Acid as a Precursor of Thermoplastic Polyimide Compounds)

Add 82.1kg of DMF cooled to 10°C, 12.18kg of 2,2-bis[4-(4-aminophenoxy)phenyl]sulfone (BAPS), and slowly add 7.87kg of 3,3',4,4'-Biphenyltetracarboxylic dianhydride (BPDA). Next, 380 g of ethylene bis(trimellitic acid monoester anhydride) (TMEG) was added, and it stirred for 30 minutes. Separately, a solution obtained by dissolving 300 g of TMEG in 3 kg of DMF was prepared, and this was slowly added to the above reaction solution while paying attention to the viscosity, followed by stirring. When the viscosity reached 3000 poise, the addition and stirring were stopped to obtain a solution of polyamic acid which is a precursor of a thermoplastic polyimide compound.

In this synthesis example, when the thickness of each layer was measured by an infrared absorption method, the functional group exhibiting a characteristic infrared absorption wavelength was a sulfo group derived from BAPS.

(Synthesis Example 5: Synthesis of Polyamic Acid as a Precursor of Thermoplastic Polyimide Compounds)

Add 86.2kg of DMF cooled to 10°C, 6.6kg of 1,3-bis(4-aminophenoxy)benzene (TPE-R), and slowly add 6.9kg of 2,3' while stirring under nitrogen atmosphere , 3,4'-biphenyltetracarboxylic dianhydride (a-BPDA). Separately, a solution obtained by dissolving 300 g of TPE-R in 3 kg of DMF was prepared, and this was slowly added to the above reaction solution while paying attention to the viscosity, followed by stirring. When the viscosity reached 3000 poise, the addition and stirring were stopped to obtain a solution of polyamic acid which is a precursor of a thermoplastic polyimide compound.

In this synthesis example, when the thickness of each layer was measured by an infrared absorption method, there was no functional group exhibiting a characteristic infrared absorption wavelength.

Table 2 shows the resins and characteristic infrared absorbing functional groups in Synthesis Examples (1) to (5).

(Measurement of the thickness of each layer of the adhesive film)

The film thickness of each layer of the film was measured using a multilayer film thickness measuring device KE-500ML manufactured by Kurabo Corporation. A case where a multilayer film could be recognized and the film thickness of each layer could be measured was rated as ○, and a case where a multilayer film was not recognized and the film thickness of each layer could not be measured was rated as ×.

(Example 1)

The solution of the polyamic acid which is the precursor of the highly heat-resistant polyimide obtained in the synthesis example 1 contained the following chemical dehydrating agent and catalyst.

1. Chemical dehydrating agent: 2.0 mol of acetic anhydride with respect to 1 mol of amic acid units of the polyamic acid which is the precursor of a highly heat-resistant polyimide.

2. Catalyst: 0.3 mol of isoquinoline with respect to 1 mol of amic acid units of polyamic acid which is a precursor of a highly heat-resistant polyimide.

Then, the multi-layer film is continuously extruded from a multi-manifold type 3-layer co-extrusion multi-layer die with a flange width of 650 mm. The multi-layer film is the thermoplastic polyimide obtained in Synthesis Example 3. The polyamic acid solution of the precursor of the amine, and the polyamic acid solution of the precursor of the highly heat-resistant polyimide solution for the inner layer are sequentially formed, and the cast is made of stainless steel that moves 20 mm below the T-shaped die. on the ring belt. Next, the multilayer film was transformed into a self-supporting gel film by heating at 130° C. for 100 seconds. In this gel film, delamination was not observed, and it was a gel film with a good appearance. Furthermore, the self-supporting gel film was peeled off from the endless belt, fixed to the clips of the tenter, and dried under the conditions of 300° C.×30 seconds, 400° C.×50 seconds, and 450° C.×10 seconds. to obtain an adhesive film.

The film thickness of each layer of the polyimide adhesive film was measured with a multilayer film thickness measuring device KE-500ML manufactured by KURABO Co., Ltd. As a result, the infrared ray with a wave number near 1700 cm ^-1 , which is a characteristic of polyimide resin, The absorption can measure the total film thickness of the three-layer film, and the infrared absorption near the wave number 2900cm ^-1 characteristic of the methyl group can measure the film thickness of the cover layer 1, and the wave number 1300cm ^-1 characteristic of the sulfo group The infrared absorption in the vicinity can measure the film thickness dimension of the cover layer 2, so the above-mentioned film thickness meter is installed in the process after leaving the tenter furnace. The film thickness gauge is a mechanism that can measure the film thickness while moving at a speed of 120mm/sec in the width direction of the multilayer film. The film thickness of each layer of the multi-layer film measured by the film thickness gauge and the position of the width direction of the film are successively transmitted to the control system. In order to obtain the desired film thickness, the control system controls the The heating element sends at least one energization signal of energization current or energization time, and sends a rotation signal as a motor rotation angle to the flange movable motor at intervals of once/5 seconds to control the film thickness dimension.

In the mechanical conveyance direction and the width direction of the obtained film, the multilayer film thickness measuring device KE-500ML manufactured by KURABO Co., Ltd. was used to measure at a pitch of 10 mm, and the film thickness deviation was obtained. As a result, the film thickness deviation of each layer was 8 %the following.

(Example 2)

In addition to using the polyamic acid solution obtained in Synthesis Example 4 as a precursor of thermoplastic polyimide instead of the polyamic acid solution obtained in Synthesis Example 3 as a precursor of thermoplastic polyimide, the same as in Example 1 An adhesive film is produced in the same manner. The film thickness variation of each layer is 7% or less.

(Example 3)

The polyamic acid solution obtained as the precursor of the high heat-resistant polyimide obtained in Synthesis Example 2 is used to replace the polyamic acid solution obtained in Synthesis Example 1 as the precursor of the highly heat-resistant polyimide, Using the polyamic acid solution obtained in Synthesis Example 5 as a precursor of thermoplastic polyimide instead of the polyamic acid solution obtained in Synthesis Example 3 as a precursor of thermoplastic polyimide, in addition, with An adhesive film was produced in the same manner as in Example 1. The film thickness variation of each layer is 7% or less.

(comparative example 1)

In addition to using the polyamic acid solution obtained in Synthesis Example 5 as a precursor of thermoplastic polyimide instead of the polyamic acid solution obtained in Synthesis Example 3 as a precursor of thermoplastic polyimide, the same as in Example 1 An adhesive film is produced in the same manner.

(comparative example 2)

In addition to using the polyamic acid solution obtained in Synthesis Example 2 as a precursor of high heat-resistant polyimide instead of the polyamic acid solution obtained in Synthesis Example 1 as a precursor of high heat-resistant polyimide Except for this, an adhesive film was produced in the same manner as in Example 1.

Table 1 shows the resin composition and layer thickness measurement results of each layer in Examples 1 to 3 and Comparative Examples 1 and 2.

Table 1

High heat resistance polyimide layer adhesive layer The measurement results Acid dianhydride/mol% Diamine/mol% Acid dianhydride/mol% Diamine/mol% Example 1 BPDA/100 PDA/100 BPDA/95 TMEG/5 BAPP/100 ○ Example 2 BPDA/100 PDA/100 BPDA/95 TMEG/5 BAPS/100 ○ Example 3 PMDA/45 BTDA/55 PDA/50 BAPP/20 ODA/30 a-BPDA/100 TPE-R/100 ○ Comparative example 1 BPDA/100 PDA/100 a-BPDA/100 TPE-R/100 × Comparative example 2 PMDA/45 BTDA/55 PDA/50 BAPP/20 ODA/30 BPDA/95 TMEG/5 BAPP/100 ×

As shown in the examples, when either the high heat-resistant polyimide layer or the adhesive layer is mainly composed of a polyimide resin containing a functional group exhibiting a characteristic infrared absorption wavelength, the thickness of the infrared absorption method can be used. Measuring device to correctly detect the thickness of each layer.

(Example 4)

The multi-manifold multi-layer die 40 shown in FIG. 3 uses a three-layer co-extrusion die equipped with a heating element 43 to perform co-extrusion production of a polyimide three-layer film. Table 3 shows the polyimide resin compositions of the core layer and the cover layer.

A part of the flow path 44 on both sides of the outer layer (covering layers 1 and 2) of the three-layer co-extrusion die can be heated with a heating element 43 (diameter 6.5 mm, electric sheath heater). In addition, the flange interval of the die is 0.8 mm, and the flange width adjustment mechanism 47 is a mechanism capable of movably adjusting the flange interval with a precision of 10 μm by a motor. These film thickness dimension adjustment mechanisms were provided at intervals of 12.5 mm in the width direction of the multilayer die. The multilayer die has a width of 600 mm, and cooling is performed at 0° C. by allowing the refrigerant to flow through the refrigerant circulation holes 46 provided in the multilayer die.

The following chemical dehydrating agent and catalyst were contained in the polyamic-acid solution which is the precursor of the highly heat-resistant polyimide obtained in the synthesis example 1.

1. Chemical dehydrating agent: 2.0 mol of acetic anhydride with respect to 1 mol of amic acid units of the polyamic acid which is the precursor of a highly heat-resistant polyimide.

2. Catalyst: 0.3 mol of isoquinoline with respect to 1 mol of amic acid units of polyamic acid which is a precursor of a highly heat-resistant polyimide.

Next, the polyamic acid solution which is the precursor of the above-mentioned highly heat-resistant polyimide resin solution is used as the core layer, and the polyamic acid solution which is the precursor of the thermoplastic polyimide obtained in Synthesis Example 3 is used as the cover layer 1 , the polyamic acid solution of the precursor of the thermoplastic polyimide obtained in Synthesis Example 4 is used as the cover layer 2, and the multilayer film is continuously extruded from the above-mentioned three-layer co-extrusion die, and cast on a 15m / min speed on the stainless steel endless belt. Next, the multilayer film was transformed into a self-supporting gel film by heating at 130° C. for 100 seconds. In this gel film, delamination was not observed, and it was a gel film with a good appearance. Furthermore, the self-supporting gel film was peeled off from the endless belt, fixed to the clips of the tenter, and dried in a tenter oven under the conditions of 300°C x 30 seconds, 400°C x 50 seconds, and 450°C x 10 seconds. and imidization to obtain a polyimide three-layer film in which the covering layers of the two outer layers are thermoplastic polyimide compounds, and the central core layer is formed of high heat-resistant polyimide compounds.

The film thickness of each layer of the obtained polyimide three-layer film was measured with a multilayer film thickness measuring device KE-500ML manufactured by KURABO Corporation. As a result, the characteristic absorption wavelength of polyimide resin near 1700 ^cm The infrared absorption can measure the total film thickness of the three-layer film, and the infrared absorption around 2900cm ^- 1, which is the characteristic of the methyl group, can measure the film thickness of the cover layer 1, and the characteristic of the sulfonic group. The infrared absorption near 1300 cm ⁻¹ can measure the film thickness of the cover layer 2 , so the above-mentioned film thickness meter is installed in the process after leaving the tenter furnace. The film thickness gauge is a mechanism that can measure the film thickness while moving at a speed of 120mm/sec in the width direction of the multilayer film. The film thickness of each layer of the multilayer film measured by the film thickness gauge and the position of the width direction of the film are successively transmitted to the control system. In order to obtain the desired film thickness, the control system heats the The element transmits at least one energization signal of energization current or energization time, and transmits a rotation signal as a motor rotation angle to the flange movable motor at intervals of once/5 seconds to control the film thickness dimension.

As a result, the variation in the thickness of each layer was 20% when the control system did not control the thickness of the layer, while the variation in the thickness of each layer was within 1% when the thickness was controlled. The deviation of the film thickness dimension in the mechanical conveyance direction and the width direction of the obtained film was measured and determined at a pitch of 10 mm with a multilayer film thickness measuring device KE-500ML manufactured by KURABO Corporation.

(Example 5)

The polyamic acid solution of the precursor of the thermoplastic polyimide obtained in Synthesis Example 5 was used for the cover layer 1 instead of the polyamic acid solution of the precursor of the thermoplastic polyimide obtained in Synthesis Example 3 for the cover layer 1. In layer 1, the polyamic acid solution of the precursor of the highly heat-resistant polyimide obtained in Synthesis Example 2 was used for the core layer instead of the precursor of the highly heat-resistant polyimide obtained in Synthesis Example 1. The polyamic acid solution was used for the core layer, except that, a polyimide three-layer film was produced with the same device as in Example 1. Table 3 shows the polyimide resin compositions of the core layer and the cover layer.

As a result, the variation in the thickness of each layer was 20% when the control system did not control the thickness of the layer, while the variation in the thickness of each layer was within 1% when the thickness was controlled.

(Example 6)

Except that the polyamic acid solution of the precursor of the thermoplastic polyimide obtained in Synthesis Example 3 was used for the cover layer 1 and the cover layer 2 instead of the polyamide of the precursor of the thermoplastic polyimide obtained in Synthesis Example 4. Except that the acid solution was used for the cover layer 2, a polyimide three-layer film was produced with the same apparatus as in Example 1. Table 3 shows the polyimide resin compositions of the core layer and the cover layer.

As a result, the variation in the film thickness of each layer was 20% when the control system did not control the film thickness, while the variation in the film thickness of the core layer was within 1% when the film thickness was controlled. , the film thickness dimensional deviation of each layer of the cover layer is within 2%.

(comparative example 3)

Except that the polyamic acid solution of the precursor of the thermoplastic polyimide obtained in Synthesis Example 5 is used for the cover layer 1 and the cover layer 2 instead of the polyamide of the precursor of the thermoplastic polyimide obtained in Synthesis Example 2 Except for the acid solution, a polyimide three-layer film was produced in the same manner as in Example 1. Table 3 shows the polyimide resin compositions of the core layer and the cover layer.

The film thickness of each layer of the obtained polyimide three-layer film was measured with a multilayer film thickness measuring device KE-500ML manufactured by KURABO Corporation. The total film thickness of the three-layer film is measured, but the film thickness of each layer cannot be measured, and the film thickness of each layer cannot be controlled.

(comparative example 4)

The polyamic acid solution of the precursor of the highly heat-resistant polyimide obtained in Synthesis Example 2 was used for the core layer instead of the polyamide using the precursor of the highly heat-resistant polyimide obtained in Synthesis Example 1 Acid solution, using the polyamic acid solution of the precursor of thermoplastic polyimide obtained in Synthesis Example 3 for the cover layer 2 instead of the polyamic acid solution of the precursor of thermoplastic polyimide obtained in Synthesis Example 4 , except that, a polyimide three-layer film was produced with the same apparatus as in Example 1. Table 3 shows the polyimide resin compositions of the core layer and the cover layer.

The film thickness of each layer of the obtained polyimide three-layer film was measured with a multilayer film thickness measuring device KE-500ML manufactured by KURABO Corporation. The total film thickness of the three-layer film is measured, but the film thickness of each layer cannot be measured, and the film thickness of each layer cannot be controlled.

Table 2

Synthetic example Resin Characteristic infrared absorbing functional groups Synthesis 1 High heat resistance polyimide compound none Synthesis 2 ↑ Methyl Synthesis 3 Thermoplastic polyimide compounds Methyl Synthesis 4 ↑ Sulfur Synthesis 5 ↑ none

table 3 Example cover 1 core cover 2 Example 4 Synthesis 3 synthesis 1 Synthesis 4 Example 5 Synthesis 5 synthesis 2 Synthesis 4 Example 6 Synthesis 3 synthesis 1 Synthesis 3 Comparative example 3 Synthesis 5 synthesis 1 Synthesis 5 Comparative example 4 Synthesis 3 synthesis 2 Synthesis 3

Claims (8)

1. polyimide multilayered adhesive film, adhesive layer that it is formed with high-fire resistance polyimide layer and at least one surface of the high-fire resistance polyimide layer, containing thermoplastic polyimide, it is characterized in that, using the polyimide resin of the functional group containing display characteristic infrared ray absorbing wavelength as main component, the film thickness deviation of each layer is ± the 10% or less of each layer average thickness for high-fire resistance polyimide layer or adhesive layer.

2. polyimide multilayered adhesive film, adhesive layer that it is formed with high-fire resistance polyimide layer and at least one surface of the high-fire resistance polyimide layer, containing thermoplastic polyimide, it is characterized in that, the bonding film is manufactured with co-extrusion pressure-cast coating method, also, high-fire resistance polyimide layer or adhesive layer are using the polyimide resin of the functional group containing display characteristic infrared ray absorbing wavelength as main component.

3. polyimide multilayered adhesive film according to claim 1 or 2, its three-decker for containing high-fire resistance polyimides and adhesive layer formed on the two sides of the high-fire resistance polyimide layer, containing thermoplastic polyimide, it is characterized in that at least two or more the layers in described three layers are respectively with the polyimide resin layer as main component of the functional group containing different display characteristic infrared ray absorbing wavelengths.

4. polyimide multilayered adhesive film described in any one of claim 1 to 3, it is characterized in that, the functional group of display characteristic infrared ray absorbing wavelength is methyl, sulfo group, fluoromethyl.

5. the manufacturing method of polyimide multilayered adhesive film, be manufacture at least two layers or more, the method for multilayer film containing polyimide resin, it is characterized in that, including following processes:

The production process of polyimide multilayered adhesive film, layer more than at least one of the polyimide multilayered adhesive film are with the polyimide resin layer as main component of the functional group containing display characteristic infrared ray absorbing wavelength；

Infrared ray is irradiated on the thickness direction of the film to measure the distribution of the absorbing wavelength of infrared ray, the process of the film thickness size of each layer is calculated by the infrared ray absorbing amount of the characteristic wavelength range of each layer；

By the film thickness dimension data feedback of calculating to the production process of multilayer film, apply the process for adjusting the operation of each tunic thickness in production process.

6. the manufacturing method of polyimide multilayered adhesive film according to claim 5, it is characterized in that, the Polymeric multilayer is formed by the layer containing high-fire resistance polyimide resin and the layer containing thermoplastic polyimide resin.

7. the manufacturing method of polyimide multilayered adhesive film according to claim 6, wherein the structure of the Polymeric multilayer is, on the two sides of the layer containing high-fire resistance polyimide resin, configured with the layer containing thermoplastic resin polyimide resin.

8. the manufacturing method of the polyimide multilayered adhesive film according to any one of claim 5~7, it is characterized in that, in the production process of the polyimide multilayered adhesive film, in the film surface containing the layer containing polyimide resin more than at least one layer, it is coated with the solution containing polyamic acid or polyimide resin, it heated, dried, is film-made by method so.

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