JP4894866B2 - Multilayer polyimide film and laminate - Google Patents

Description

  The present invention relates to a multilayer polyimide film and a laminate of a multilayer polyimide film and a metal layer, and in particular, a specific polyimide layer is applied on one side or both sides of a low thermal linear expansion base polyimide layer by a coating method or multilayer extrusion casting. The present invention relates to a multilayer polyimide film laminated by a molding method such as a film molding method and a laminate with a metal using this film.

  Conventionally, aromatic polyimide films have been widely used as applications for electronic devices such as cameras, personal computers, and liquid crystal displays. In order to use an aromatic polyimide film as a substrate material such as a flexible printed board (FPC) or tape-automated bonding (TAB), a copper foil is bonded using an adhesive such as an epoxy resin. The method is adopted.

  Aromatic polyimide films are excellent in heat resistance, mechanical strength, electrical characteristics, etc., but it has been pointed out that since the heat resistance of adhesives such as epoxy resins is inferior, the characteristics of the original polyimide are impaired. In order to solve such problems, copper is electroplated on the polyimide film without using an adhesive, or a polyamic acid solution is applied to the copper foil, followed by drying, imidization, or thermocompression bonding of thermoplastic polyimide. An all-polyimide substrate has also been developed.

  Also known is a polyimide laminate in which a film-like polyimide adhesive is sandwiched between a polyimide film and a metal foil, and a method for producing the same (Patent Document 1). However, this polyimide laminate has a problem that its peel strength (adhesive strength) is small and its use is restricted.

In order to solve these problems, the applicants proposed a method and a material for producing a polyimide film by multilayer extrusion in Patent Document 2 and Patent Document 3. Many problems were solved by these, but in the material of the composition used for the thin layer portion disclosed in the publication, the surface was dissolved by leaching into a chlorinated solvent such as methylene chloride (whitening of the film occurred) May cause problems depending on the application. Further, fine adjustment of the melting temperature is difficult with the monomer composition specifically shown in the above publication. Although the adhesiveness was improved by the introduction of an amine end-capping agent as shown in the examples, it was found that dissolution and whitening in the above solvent were promoted. This solvent is considered to be used in the cleaning process during the production of the wiring board.
U.S. Pat. No. 4,543,295 Japanese Patent Publication No. 7-102648 Japanese Patent Laid-Open No. 10-138318

  The object of the present invention is that it can be laminated with a metal foil under relatively mild conditions, has excellent durability against chlorinated solvents, and can control the glass transition temperature widely, so that a wide range of bonding conditions can be selected, and it can be used at high temperatures. The present invention provides a multilayer polyimide film and a metal laminate using the film that can withstand.

  The present invention provides the following formula on at least one side of the low thermal expansion base polyimide (X) layer.

[In the formula, Ar ₁ is 50 of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride residue and 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride residue: It is an aromatic tetracarboxylic dianhydride residue having a molar ratio of 50 to 90:10, and Ar ₂ is an aromatic diamine residue that is 1,3-bis (4-aminophenoxy) benzene . ] It is related with the multilayer polyimide film which has the thin layer polyimide (Y) which has an imide unit shown. Moreover, this invention relates to the laminated body formed by laminating | stacking the said multilayer polyimide film and a metal layer through the said thin layer polyimide (Y).

  According to this invention, since it has the above-described configuration, it can be laminated with a metal foil under relatively relaxed conditions, has excellent durability against chlorinated solvents, and can be widely controlled by controlling the glass transition temperature. A multilayer polyimide film that can select a wide range of conditions and can withstand high temperature use can be obtained.

  Moreover, according to this invention, the durability with respect to a chlorine-type solvent is excellent, and the metal layer laminated polyimide film laminated body (flexible metal foil laminated body) which can endure use of high temperature can be obtained.

The preferred embodiments of the present invention are listed below.
1) The base polyimide has the following formula

［式中、ｍ／ｎ（モル比）＝１００／０〜７０／３０である。］で示されるイミド単位を有する請求項１に記載の多層ポリイミドフィルム。

[Wherein, m / n (molar ratio) = 100/0 to 70/30. ] The multilayer polyimide film of Claim 1 which has an imide unit shown by these.

2) At least one side of the base polyimide (X) layer by coextrusion casting and casting polyamic acid solution for base layer giving base polyimide (X) and polyamic acid solution for thin layer giving thin layer polyimide (Y) The above multilayer polyimide film obtained by laminating and integrating a thin layer polyimide (Y).
3) Thinly apply the thin layer polyamic acid solution for providing the thin layer polyimide (Y) on at least one surface of the self-supporting film formed from the base layer polyamic acid solution for providing the base polyimide (X), heat-dry, Said multilayer polyimide film formed by imidization.

4) The above laminate obtained by laminating a thin polyimide (Y) layer of a multilayer polyimide film and a metal foil, followed by thermocompression bonding.
5) The above laminate obtained by forming a metal layer by vapor deposition and / or plating on a thin polyimide (Y) layer of a multilayer polyimide film.
6) Said laminated body whose thickness (one side, total thickness) of a metal layer is 4-35 micrometers, Preferably it is 4-9 micrometers.

  As the base polyimide constituting the base polyimide layer of the multilayer polyimide fill in this invention, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, p-phenylenediamine and 4,4′-diaminodiphenyl ether It has a low linear expansion coefficient close to that of a circuit metal such as polyimide obtained by polymerizing and imidizing an aromatic diamine having a ratio of 100/0 to 70/30, particularly copper, which is advantageous. Of course, other types of polyimide can be used in the same manner as a polyimide for providing a polyimide film having a low linear expansion coefficient in the field of electronic technology.

  In the present invention, as a polyimide for a thin layer constituting a thin polyimide layer of a multilayer polyimide film, the following formula

[In the formula, Ar ₁ is 50 of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride residue and 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride residue: It is an aromatic tetracarboxylic dianhydride residue having a molar ratio of 50 to 90:10, and Ar ₂ is an aromatic diamine residue that is 1,3-bis (4-aminophenoxy) benzene . It is necessary to use a polyimide having an imide unit represented by

The polyimide for thin layers having the imide unit is preferably 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (sometimes abbreviated as s-BPDA) and 2,3,3. An aromatic tetracarboxylic dianhydride component (component and component) having a molar ratio of 50:50 to 90:10 with ', 4'-biphenyltetracarboxylic dianhydride (sometimes abbreviated as a-BPDA). Represents an esterified product of an acid or an alkyl alcohol having 1 to 4 carbon atoms) and an aromatic diamine which is 1,3-bis (4-aminophenoxy) benzene, and is a polyimide obtained by imidization. Is mentioned. As long as the properties of the thin layer polyimide are not impaired, a part of the biphenyltetracarboxylic dianhydride component and the aromatic diamine may be replaced with other types of tetracarboxylic dianhydride components and / or aromatic diamines. Also good.

  Regarding the proportion of each of the above-mentioned components, the glass transition temperature decreases as the molar ratio of s-BPDA increases, and is about 260 ° C. at 100 mol% of a-BPDA, 250 ° C. at 50 mol%, and 10 mol%. The soldering heat resistance at high temperature tends to decrease. Therefore, the amine component 1,3-bis (4-aminophenoxy) benzene is replaced with p-phenylenediamine (hereinafter sometimes simply referred to as PPD) or diaminodiphenyl ether, particularly 4,4′-diaminodiphenyl. By substituting with ether (hereinafter sometimes abbreviated simply as DADE), it is possible to increase the glass transition temperature by 60 ° C. or more while dissolving in methylene chloride, not whitening the surface, and having adhesiveness. The glass transition temperature can be arbitrarily changed from 210 ° C. to about 310 ° C. Adhesion is possible even at a higher glass transition temperature, but the temperature at the time of pressing rises and the productivity is significantly reduced.

  Further, from the viewpoint of dissolution and whitening in a chlorine-based solvent, it is preferable to avoid acid excess (and hence carboxylic anhydride terminal blocking). Further, since Tg and the like are controlled by the composition, it is not necessary to add a carboxylic anhydride for amine terminal blocking in order to control the molecular weight.

  The polyimide for a thin layer is prepared by reacting each of the above components in an organic solvent at a temperature of about 100 ° C. or less, particularly 20 to 60 ° C. to obtain a polyamic acid solution, which is further added to the polyamic acid solution or the polyamic acid solution. A film prepared by adding an organic solvent to adjust the polyamic acid concentration is used as a dope, and a thin film of the above-mentioned dope liquid is used as a base polyimide layer (base polyimide dope liquid film or base polyimide self-supporting film). Can be formed by heating and drying at 50 to 400 ° C. for about 1 to 30 minutes to evaporate and remove the solvent from the thin film and imide cyclization of the polyamic acid. The polyamic acid dope that provides the thin layer polyimide preferably has a polyamic acid concentration of about 1 to 20% by weight.

In the present invention, the multilayer polyimide film preferably has a thermocompression bonding property and a linear expansion coefficient (50 to 200 ° C.) (MD) of 30 × 10 ⁻⁶ cm / cm / ° C. or less, particularly 15 × 10 ⁻ Those having a thickness of ^{6 to} 25 × 10 ⁻⁶ cm / cm / ° C. and a thickness of 10 to 150 μm are preferable, and those having a tensile elastic modulus (MD, ASTM-D882) of 300 kg / mm ² or more are preferable.

  The above-mentioned multilayer polyimide film is preferably formed by laminating a polyimide solution for a substrate and a polyimide solution for a thin layer by a coextrusion-casting film forming method (also simply referred to as a multilayer extrusion method). A method of obtaining a multilayer polyimide film by drying and imidization, or applying the above-mentioned polyimide dope solution for a substrate onto a support and applying a thin film on one or both sides of a dried self-supporting film (gel film). It can be obtained by a method of applying a layer polyimide solution, drying and imidizing to obtain a multilayer polyimide film.

  In order to limit the gelation of the polyamic acid, a phosphorous stabilizer such as triphenyl phosphite, triphenyl phosphate is 0.01 to 1% based on the solid content (polymer) concentration during polyamic acid polymerization. It can be added in the range of. For the purpose of promoting imidization, an imidizing agent can be added to the dope solution. For example, imidazole, 2-imidazole, 1,2-dimethylimidazole, 2-phenylimidazole, benzimidazole, isoquinoline, substituted pyridine and the like are 0.05 to 10 weights with respect to the polyamic acid. %, Especially 0.1 to 2% by weight. They can complete the imide at relatively low temperatures.

  For the purpose of stabilizing the adhesive strength, an organoaluminum compound, an inorganic aluminum compound, or an organotin compound may be added to the thermocompression bonding polyimide raw material dope. For example, aluminum hydroxide, aluminum triacetylacetonate or the like can be added in an amount of 1 ppm or more, particularly 1 to 1000 ppm as an aluminum metal with respect to the polyamic acid.

  The polyimide as the substrate layer is preferably 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and paraphenylenediamine (hereinafter sometimes abbreviated as PPD) and optionally further 4 in some cases. , 4′-diaminodiphenyl ether (hereinafter sometimes simply referred to as DADE). In this case, the PPD / DADE (molar ratio) is preferably 100/0 to 85/15. Further, polyimide as a base layer is composed of 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA), pyromellitic dianhydride (PMDA), paraphenylenediamine (PPD), and 4,4. It is produced from '-diaminodiphenyl ether (DADE). In this case, it is preferable that BTDA in acid dianhydride is 20 to 90 mol%, PMDA is 10 to 80 mol%, PPD in diamine is 30 to 90 mol%, and DADE is 10 to 70 mol%.

In addition, as the heat-resistant polyimide as the base layer, it is preferable that the glass transition temperature is 350 ° C. or higher in the case of a single polyimide film, and in particular, the linear expansion coefficient (50 to 200 ° C.) (MD ) Is preferably 5 × 10 ⁻⁶ to 30 × 10 ⁻⁶ cm / cm / ° C. The tensile modulus (MD, ASTM-D882) is preferably 300 kg / mm ² or more. The synthesis of the base layer polyimide is performed by random polymerization, block polymerization, or by synthesizing two types of polyamic acids in advance and mixing both polyamic acid solutions if the proportion of each component is within the above range. To achieve a homogeneous solution.

  Using each of the above-mentioned components, a substantially equimolar amount of a diamine component and a tetracarboxylic dianhydride are reacted in an organic solvent to give a polyamic acid solution (partly imidized if a uniform solution state is maintained) May be used). Other aromatic tetracarboxylic dianhydrides and aromatic diamines such as 4,4'-diaminodiphenylmethane, etc., which do not impair the physical properties of the base layer polyimide, may be used.

  The organic solvent used for the production of the polyamic acid is N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, for both the base layer polyimide and the thin layer polyimide. N, N-diethylacetamide, dimethyl sulfoxide, hexamethylphosphoramide, N-methylcaprolactam, cresols and the like can be mentioned. These organic solvents may be used alone or in combination of two or more.

  In the production of the multilayer polyimide film, for example, a polyamic acid solution of heat-resistant polyimide for the base layer and a thermocompression bonding polyimide solution for a thin layer or a precursor solution thereof are coextruded, and this is made into a stainless steel mirror surface or belt surface. It is preferable to cast and apply on a support surface such as a semi-cured state or a dried state before that at 100 to 200 ° C. When a cast film is processed at a high temperature exceeding 200 ° C., defects such as a decrease in adhesion tend to be caused in the production of a multilayer polyimide film. This semi-cured state or an earlier state means that it is in a self-supporting state by heating and / or chemical imidization.

  The coextrusion of the polyamic acid solution for providing the base layer polyimide and the polyamic acid solution for providing the thin layer polyimide is, for example, the co-extrusion described in JP-A-3-180343 (JP-B-7-102661). It can supply to the die | dye for extrusion molding of three layers by an extrusion method, and can cast and cast on a support body. A polyimide film for a thin layer is formed by laminating a polyamic acid solution or a polyimide solution for providing a polyimide for a thin layer on one or both sides of the extrudate layer for providing the base layer polyimide to form a multi-layer film, drying, and then laminating polyimide glass Heat to a temperature below the transition temperature (Tg) and below the temperature at which deterioration occurs, preferably 250 to 420 ° C. (surface temperature measured with a surface thermometer) (preferably heated at this temperature for 1 to 60 minutes) And drying and imidizing to produce a multi-layer extruded polyimide film, preferably a thermocompression-bonding multi-layer extruded polyimide film having a thin layer polyimide on one or both sides of the base layer polyimide.

  By using the acid component and the diamine component, the thin-layer polyimide preferably has a glass transition temperature of 190 to 280 ° C, particularly 200 to 275 ° C, and preferably is dried under the above conditions. Not being melted at temperatures above the glass transition temperature and below 300 ° C. achieved by imidizing and not causing gelation of the thin layer (preferably thermocompression bonding) polyimide, and It is preferable to maintain an elastic modulus (usually, an elastic modulus at 275 ° C. is approximately 0.001 to 0.5 times the elastic modulus at 50 ° C.).

In the multilayer polyimide film, the thickness of the base layer polyimide film (layer) is preferably 5 to 125 μm, and the thickness of the thin polyimide (Y) layer is 1 to 25 μm, particularly 1 to 15 μm. 2-12 micrometers is especially preferable. Moreover, it is preferable that the thickness of the thermocompression bonding polyimide (Y) layer which is a thin layer when laminated with the other metal foil is equal to or greater than the surface roughness (Rz) of the other metal foil to be used. . In particular, as a multilayer polyimide film, it has a thermocompression bonding and / or flexible polyimide layer on both sides, and has an overall thickness of 7 to 50 μm, particularly 7 to 25 μm, and a tensile modulus (25 ° C.) of 400. What is about -1000 kgf / mm < ² > is preferable from the point of densification.

  Examples of the metal layer laminated on the multilayer polyimide film in this invention include metal foils and metal films of copper, aluminum, iron, gold and the like, and alloy foils and alloy films of these metals. Examples thereof include copper foil, vapor deposition and / or plated copper film. As the metal foil, the surface roughness is not so large and not too small, preferably the Rz of the contact surface with the thin-layer polyimide is 3 μm or less, particularly 0.5 to 3 μm, especially 1.5 to 3 μm. Is preferred. Such metal foils, such as copper foils, are known as VLP, LP (or HTE). The thickness of the metal foil is not particularly limited, but is 35 μm or less, preferably 3 to 18 μm, particularly preferably 3 μm to 12 μm. Moreover, when Rz is small, you may use what surface-treated the metal foil surface.

  In the present invention, preferably, the thermocompression-bonding multilayer polyimide film and the metal foil are continuous laminating apparatuses such as a roll laminator or a double belt press, and the thermocompression-bonding multilayer polyimide film alone or Hot air supply device, infrared heater, etc. so that it can be preheated at about 150 to 250 ° C., particularly at a temperature higher than 150 ° C. and not higher than 250 ° C. for about 2 to 120 seconds, just before introducing the thermocompression-bonding multilayer polyimide film and metal foil It is possible to obtain a laminated body that is a flexible metal foil laminated body by preheating using the preheater, and applying heat pressure bonding together. The double belt press is capable of performing high-temperature heating and cooling under pressure, and is preferably a hydraulic type using a heat medium. The above-mentioned in-line means a device arrangement in which a preheating device is installed between the raw material feeding device and the crimping part of the continuous laminating device and can be crimped immediately after.

  In particular, the laminate preferably has a roll laminating or double belt press thermocompression zone temperature of 20 ° C. higher than the glass transition temperature of thermocompression bonding polyimide and 400 ° C. or less, particularly glass. It is thermocompression bonded under pressure at a temperature of 30 ° C. or higher and 400 ° C. or lower than the transition temperature. Especially in the case of a double belt press, it is subsequently cooled under pressure with a cooling zone. It can be produced by laminating by cooling to a temperature 20 ° C. or more lower than the glass transition temperature, particularly 30 ° C. or less, and has a high adhesive strength (90 ° peel strength is 0.7 kg / cm or more, especially 1 kg) / Cm or more).

  In the above method, when the product is a flexible metal foil laminate of a single-sided metal foil, a highly heat-resistant film that can be easily peeled, such as a high-heat-resistant film or metal foil having a Rz of less than 2 μm, preferably polyimide High heat-resistant resin film such as film (Ube Industries, Upilex S) and fluororesin film, rolled copper foil, etc., and surface roughness is small (that is, smaller than Rz of the metal layer surface for circuits) A metal foil with good surface smoothness may be interposed between the thermocompression bonding polyimide layer and another metal surface as a protective material (peeling film). After the lamination, the protective material may be removed from the laminate and wound up, or the protective material may be taken up while being laminated and removed during use.

  By the above-mentioned method, particularly using a double belt, it is long and wide at about 400 mm or more, particularly about 500 mm or more, and has high adhesive strength (90 ° peel strength is 0.7 kg / cm or more, particularly 1 kg / cm) or more), and a laminate having a good appearance such that no wrinkles are substantially observed on the surface of the metal foil can be obtained.

  Moreover, the laminate in the present invention is obtained by subjecting a multilayer polyimide film in which flexible polyimide is laminated and integrated on both surfaces of a high heat resistant aromatic polyimide layer to a discharge treatment such as plasma discharge, and by a vapor deposition method, a sputtering method, a plating method, or the like. It can also be obtained by forming a metal film.

The lamination of the metal vapor deposition layer can be particularly suitably performed by a physicochemical vapor deposition method such as a vacuum vapor deposition method, an electron beam vapor deposition method, or a sputtering method. As a vapor deposition method, the degree of vacuum is about 10 ⁻⁷ to 10 ⁻² Torr, the vapor deposition rate is about 50 to 5000 kg / sec, and the temperature of the vapor deposition substrate (film) is about 20 to 600 ° C. It is preferable. In the sputtering method, the RF magnet sputtering method is particularly suitable, the degree of vacuum at that time is 1 Torr or less, particularly about 10 ⁻³ to 10 ⁻² Torr, and the substrate (film) temperature is about 20 to 450 ° C. The formation rate of the layer is preferably about 0.5 to 500 kg / second.

  Examples of the material of the metal film include copper or a copper alloy, aluminum, and palladium. Chrome, titanium, nickel, palladium, or the like may be used as the base layer, and copper may be used as the surface layer. The thickness of the underlayer is usually about 1 μm or less. In addition, a metal plating layer may be formed on the metal layer thus obtained, and examples of the material of the metal plating layer include copper, copper alloy, and silver. As a method for forming the metal plating layer, either an electroless plating method or an electrolytic plating method may be used. The thick metal film has a thickness of about 1 to 30 μm, particularly about 1 to 12 μm, and preferably 3 to 12 μm. In addition, it is preferable that the metal film is formed in a continuous roll including the sputtering and vapor deposition methods.

  In the laminate obtained by this invention, the metal layer is usually subjected to etching treatment, and then the polyimide layer is subjected to mechanical treatment such as punching or laser processing to form through holes (through holes) in the film. Form. Examples of the laser processing apparatus include a laser processing apparatus described in JP-A-10-323786. As a drilling method using a laser, for example, a laser processing method described in JP-A-6-142961 can be cited.

  For example, as a laser, a laser having an oscillation wavelength in the infrared region, such as a CO2 or YAG laser, is taken out as it is or by irradiating a nonlinear optical crystal to obtain an oscillation wavelength of 260 to 400 nm. Lasers in the ultraviolet region that are in the range of the extent can be used. For example, in the case of a laminate in which a metal layer is laminated on one side of a polyimide film, laser processing is performed by irradiating the laser with a mask that gives the polyimide layer a predetermined cross-sectional shape. A through hole having a diameter of about 30 to 300 μmφ, preferably about 50 to 100 μmφ is formed. Then, the laser processed portion is desmeared with an oxidizing agent such as an aqueous potassium permanganate solution, and then a pattern is formed on the unprocessed metal layer to form a substrate.

  For example, in the case of a laminate in which metal layers are laminated on both sides of a multilayer polyimide film, a metal layer on one side is chemically etched to form a pattern with a predetermined shape, and then the remaining metal layer is used as a mask to form polyimide. The layer is irradiated with a laser to form a through hole of about 30 to 300 μmφ, preferably about 50 to 100 μmφ, and after the laser processing portion is desmeared in the same manner as described above, another metal layer is formed. The substrate can be formed by patterning.

  The laminate obtained by laser processing by the above method and the plated substrate can be suitably used as an electronic component substrate. For example, it can be suitably used as an FPC for COF, a TAB for packaging, and a base substrate for multilayer substrates.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. In each of the following examples, the physical property evaluation and the peel strength of the metal foil laminate were measured according to the following methods.
Glass transition temperature: measured by DSC.
Crystallinity: measured by XRD (X-ray diffraction). When no peak was observed, it was evaluated as non-crystalline.
Linear expansion coefficient: measured (MD) at a heating rate of 20 to 200 ° C. and 5 ° C./min.
Peel strength of laminate: 90 ° peel strength was measured.
Heat resistance: The metal foil laminate was immersed in a solder bath at 260 ° C. for 1 minute, and the presence or absence of swelling, peeling or discoloration was observed. The case where there was no blistering, peeling or discoloration was judged as good heat resistance.

Peel strength of the laminate: Using a hot press maintained at 340 ° C., an electrolytic copper foil (thickness 35 μm) is superimposed on the polyimide film, preheated for 5 minutes, and then pressed at a pressure of 60 kgf / cm ² for 1 minute to laminate the copper foil Got the body. About this laminated body, 90 degree peel strength was measured at 50 mm / min.
Solvent resistance: after immersion in methylene chloride at room temperature (25 ° C.) for 5 minutes and then drying under reduced pressure at room temperature for 2 hours (weight after soaking) and weight before soaking: weight change rate (%) = (soaking) Post weight-weight before leaching) / weight before leaching × 100, and evaluation by visual observation of surface change (detection limit of weight loss is ± 0.5%)
Glass transition point: Tanδ peak temperature using a dynamic viscoelasticity measuring device

Example 1
Dimethylacetamide (DMAc) is added to a reaction vessel equipped with a synthetic stirrer and a nitrogen introduction tube for a substrate polyimide (X) production dope, and further paraphenylenediamine (PPD) and 3,3 ′, 4,4 '-Biphenyltetracarboxylic dianhydride (s-BPDA) was added at a molar ratio of 1000: 998 such that the monomer concentration was 18% (wt%, the same applies hereinafter). After completion of the addition, the reaction was continued for 3 hours while maintaining 50 ° C. The obtained polyamic acid solution was a brown viscous liquid, and the solution viscosity at 25 ° C. was about 1500 poise. In addition, the polyimide film with a thickness of 50 μm separately produced from this polyamic acid solution has a linear expansion coefficient (50 to 200 ° C.) (MD) of 15 × 10 ⁻⁶ cm / cm / ° C. and a tensile elastic modulus (MD, ASTM). -D882) was 756 kg / mm ² .

Synthesis of dope for producing polyimide for thin layer N, N-dimethylacetamide (DMAC) was added to a reaction vessel equipped with a stirrer and a nitrogen introduction tube, and further 1,3-bis (4-aminophenoxy) benzene (TPE-R) was added. Subsequently, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA), 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride (s-BPDA) and 50: 50 molar ratio of TPE-R: (a-BPDA + s-BPDA) so that the monomer concentration is 22% at a molar ratio of 1000: 992, and 0.1% of triphenyl phosphate is added to the monomer weight. It was. After completion of the addition, the reaction was continued at 25 ° C. for 4 hours to obtain a light brown transparent viscous polyamic acid solution. The solution viscosity at 25 ° C. was about 1500 poise.

Manufacture of multilayer polyimide film with two-layer structure Extruded from a two-layer extrusion die onto the upper surface of a smooth metal support, continuously dried with hot air at 140 ° C, and solidified film (self-supporting film) After forming and peeling the solidified film from the support, the temperature was gradually raised from 200 ° C. to 350 ° C. in a heating furnace to remove the solvent and imidize the polymer, and the thickness was 35 μm [thin layer ( A multilayer polyimide film having a two-layer structure having a thickness of 10 μm and a base polyimide of 25 μm] was produced.

Manufacture of Laminate A 35 μm copper foil is superimposed on this thermocompression thin layer (Y) polyimide film, and a 12 μm aluminum foil is further superimposed on the copper foil. It arrange | positioned between the hot plates in a press, and thermocompression bonding was performed for 5 minutes by the pressure of 50 kg / cm < ² > at the temperature of 340 degreeC, and the metal foil laminated polyimide film was manufactured. Table 1 shows the glass transition temperature Tg of the film thus obtained, the weight reduction rate of the film after 5 minutes of immersion in methylene chloride, the result of visual observation, and the 90 ° peel strength of the metal foil laminated polyimide film. .

Example 2
In order to obtain a polyimide layer for a thin layer, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA) and 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride A multilayer polyimide film and a metal foil laminated polyimide film were produced in the same manner as in Example 1 except that the ratio of (s-BPDA) was 35:65. The results are shown in Table 1.

Example 3
In order to obtain a polyimide layer for a thin layer, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA) and 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride A multilayer polyimide film and a metal foil laminated polyimide film were produced in the same manner as in Example 1, except that the ratio of (s-BPDA) was 25:75. The results are shown in Table 1.

Example 4
In order to obtain a polyimide layer for a thin layer, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA) and 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride A multilayer polyimide film and a metal foil laminated polyimide film were produced in the same manner as in Example 1 except that the ratio of (s-BPDA) was 15:85. The results are shown in Table 1.

Comparative Example 1
In order to obtain a polyimide layer for a thin layer, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA) and 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride A multilayer polyimide film was produced in the same manner as in Example 1 except that the ratio of (s-BPDA) was changed to a molar ratio of 100: 0. After methylene chloride leaching, the weight decreased by 16.9% and was visually altered.

Comparative Example 2
In order to obtain a polyimide layer for a thin layer, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA) and 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride A multilayer polyimide film was produced in the same manner as in Example 1 except that the ratio of (s-BPDA) was changed to a molar ratio of 75:25. After methylene chloride infiltration, the weight decreased by 1.3%, which was clearly altered visually.

Comparative Example 3
In order to obtain a polyimide layer for a thin layer, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA) and 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride A multilayer polyimide film and a metal foil laminated polyimide film were produced in the same manner as in Example 1 except that the ratio of (s-BPDA) was changed to a molar ratio of 0: 100. The peel strength of the metal foil laminated polyimide film was 0 g and was not adhered at all.

いずれも、重量減が±０．５％以下、表面目視○、剥離強度１．１ｋｇ／ｃｍ以上で、良好であった。

In all cases, weight loss was ± 0.5% or less, surface observation ○, and peel strength of 1.1 kg / cm or more, which were favorable.

Experimental example 1
For the production of polyimide for thin layers, N, N-dimethylacetamide (DMAc) is added, and 1,3-bis (4-aminophenoxy) benzene (TPE-R), 4,4′-diaminodiphenyl ether (DADE) At a molar ratio of 75:25, followed by 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA), 3,4,3 ′, 4′-biphenyltetracarboxylic acid A multilayer polyimide film and a metal foil laminated polyimide film were produced in the same manner as in Example 1 except that dianhydride (s-BPDA) was added at a molar ratio of 50:50. The results are shown in Table 2.

Experimental example 2
The ratio of each component in the synthesis | combination of the dope for polyimide manufacture for thin layers was carried out similarly to Experimental example 1 except having set it as the molar ratio of TPE-R: DADE = 50: 50 and a-BPDA: s-BPDA = 50: 50. Thus, a multilayer polyimide film and a metal foil laminated polyimide film were produced. The results are shown in Table 2.

Experimental example 3
The ratio of each component in the synthesis | combination of the dope for polyimide manufacture for thin layers was carried out similarly to Experimental example 1 except having set it as the molar ratio of TPE-R: DADE = 25: 75 and a-BPDA: s-BPDA = 50: 50. Thus, a multilayer polyimide film and a metal foil laminated polyimide film were produced. The results are shown in Table 2.

いずれも、重量減が±０．５％以下、表面目視○、剥離強度０．８ｋｇ／ｃｍ以上で、良好であった。

In all cases, the weight loss was ± 0.5% or less, the surface visual observation ○, and the peel strength 0.8 kg / cm or more.

Experimental Example 4
For production of thin layer polyimide, N, N-dimethylacetamide (DMAc) was added, and 1,3-bis (4-aminophenoxy) benzene (TPE-R) and paraphenylenediamine (PPD) were added at 90:10. Followed by 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA), 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride ( A multilayer polyimide film and a metal foil laminated polyimide film were produced in the same manner as in Experimental Example 1 except that s-BPDA) was added at a molar ratio of 50:50. The results are shown in Table 3.

Experimental Example 5
The ratio of each component in the synthesis | combination of the dope for polyimide manufacture for thin layers was carried out similarly to Experimental example 1 except having set it as the molar ratio of TPE-R: PPD = 50: 50 and a-BPDA: s-BPDA = 50: 50. Thus, a multilayer polyimide film and a metal foil laminated polyimide film were produced. The results are shown in Table 3.

いずれも、重量減が±０．５％以下、表面目視○、剥離強度０．９ｋｇ／ｃｍ以上で、良好であった。

In all cases, weight loss was ± 0.5% or less, surface observation ○, and peel strength of 0.9 kg / cm or more.

Example 5
From the polyamic acid solution for thin layer polyimide and the polyamic acid solution for base polyimide in Example 1, a multilayer polyimide film having a thickness constitution of 4 μm / 10 μm / 4 μm was obtained. This multilayer polyimide film and an electrolytic copper foil having a thickness of 18 μm (manufactured by Mitsui Metal Mining Co., Ltd., 3EC-VLP, Rz: 3.8 μm) are continuously supplied to a double belt press, and after preheating, the temperature of the heating zone ( (Maximum heating temperature) 380 ° C. (setting), cooling zone temperature (minimum cooling temperature) 117 ° C.), continuously laminated under pressure and thermocompression-cooling, metal foil laminated polyimide film (width: about 530 mm) A roll roll was obtained. The obtained metal foil laminated polyimide film exhibited the same characteristics as in Example 1.

Claims (9)

At least one side of the low thermal expansion base polyimide (X) layer has the following formula

[In the formula, Ar ₁ is 50 of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride residue and 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride residue: It is an aromatic tetracarboxylic dianhydride residue having a molar ratio of 50 to 90:10, and Ar ₂ is an aromatic diamine residue that is 1,3-bis (4-aminophenoxy) benzene. ] The multilayer polyimide film which has the thin layer polyimide (Y) which has an imide unit shown. In the formula, Ar ₁ is 75:25 of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride residue and 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride residue. The multilayer polyimide film according to claim 1, which is an aromatic tetracarboxylic dianhydride residue having a molar ratio of ˜90: 10 . Base polyimide is the following formula

[Wherein, m / n (molar ratio) = 100/0 to 70/30. The multilayer polyimide film of Claim 1 or 2 which has an imide unit shown by these . A polyamic acid solution for the base layer that gives the base polyimide (X) and a polyamic acid solution for the thin layer that gives the thin layer polyimide (Y) are coextruded and thinned on at least one side of the base polyimide (X) layer by the casting film forming method. The multilayer polyimide film according to any one of claims 1 to 3, wherein the layer polyimide (Y) is laminated and integrated . Apply a thin layer polyamic acid solution for providing a thin layer polyimide (Y) to at least one surface of a self-supporting film formed from a base layer polyamic acid solution for providing a base polyimide (X), heat dry, and imidize. The multilayer polyimide film according to any one of claims 1 to 3 .   A laminate comprising the multilayer polyimide film according to any one of claims 1 to 5 and a metal layer laminated via a thin-layer polyimide (Y). The laminate according to claim 6, wherein the laminate is formed by superposing a thin polyimide (Y) layer of a multilayer polyimide film and a metal foil, followed by thermocompression bonding . The laminate according to claim 6, wherein the lamination is performed by forming a metal layer by vapor deposition and / or plating on a thin polyimide (Y) layer of a multilayer polyimide film . The laminate according to any one of claims 6 to 8, wherein the thickness of the metal layer is 3 to 35 µm .