JP2008188954A - Base material for single-sided metal-clad laminated sheet and manufacturing method of single-sided metal-clad laminated sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base material for a single-sided metal-clad laminated sheet enhanced in the adhesiveness of a high heat-resistant polyimide film and an adhesive polyimide layer and also enhanced in solder heat resistance, and a manufacturing method of the single-sided metal-clad laminated sheet using the base material for the single-sided metal-clad laminated sheet. <P>SOLUTION: The base material for the single-sided metal-clad laminated sheet is constituted by providing the adhesive polyimide layer on one of both sides of the high heat-resistant polyimide film and providing a non-adhesive polyimide layer to the other side of the high heat-resistant polyimide film. The high heat-resistant polyimide film contains the block component of a thermoplastic polyimide in an amount of 20-60 mol% with respect to the whole of a polyimide. The single-sided metal-clad laminated sheet is manufactured by laminating the base material of the single-sided metal-clad laminated sheet and a metal foil. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a substrate for a single-sided metal-clad laminate and a method for producing a single-sided metal-clad laminate that are suitably used for chip-on-film and the like.

  In recent years, the demand for various printed circuit boards has increased with the reduction in weight, size and density of electronic products. Among these printed boards, demand for chip-on-film (COF), which has both flexibility and a certain degree of stiffness in addition to thinness and lightness, is growing particularly. The COF has a structure in which an IC chip is directly mounted on a flexible printed wiring board formed of an insulating film and a metal foil.

  The COF generally has a structure in which a metal layer is provided directly or via an adhesive layer on one side of a high heat resistant polyimide film having a thickness of about 30 to 40 μm. However, the method of providing the metal layer directly on the high heat-resistant polyimide film is because the productivity is particularly low and the surface property of the high heat-resistant polyimide film is remarkably limited. A method of providing a metal layer via a gap is often employed.

  In the method of providing a metal layer via an adhesive layer on one side of a high heat-resistant polyimide film, a layer made of various adhesive materials is provided on the surface of the high heat-resistant polyimide film substrate, and then the metal foil is applied by heating and pressure bonding. A matching method is used. As the adhesive material, epoxy-based, acrylic-based thermosetting adhesives are generally used. Since the flexible wiring board using such a thermosetting adhesive has a three-layer structure of substrate / adhesive material / metal foil, it is also called a three-layer material.

  The thermosetting adhesive used for the three-layer material has an advantage that it can be bonded at a relatively low temperature. However, in the future, in addition to stricter requirements for various properties such as heat resistance, flexibility and electrical reliability against COF, halogen-containing flame retardants contained in many thermosetting adhesives may destroy the global environment. Therefore, it is difficult to cope with the three-layer material COF using a thermosetting adhesive.

  On the other hand, a substrate material using thermoplastic polyimide as an adhesive layer has been proposed. Such a substrate material is also called a two-layer material because a metal layer is directly formed on an insulating substrate. Since the two-layer material can solve the various problems of the three-layer material, demand has been growing particularly in recent years.

  However, in general, high heat-resistant polyimide film has low adhesion to thermoplastic polyimide, and in order to obtain high adhesion, surface roughening treatment such as plasma treatment and corona treatment, coupling agents and specific metal components are included. This process is necessary, and there is a problem that the cost is increased and the characteristics of the film are deteriorated (for example, see Patent Documents 1 to 3).

  In recent years, improvements in thermal dimensional stability, water absorption characteristics, and mechanical characteristics have been desired. For example, these characteristics can be obtained by adding a rigid non-thermoplastic polyimide block component with paraphenylenediamine and pyromellitic dianhydride. However, the storage stability of the polyimide precursor solution is poor, and stable industrial production is difficult unless the molecular weight is controlled to improve the storage stability (for example, Patent Document 4). 5).

Furthermore, since the high heat-resistant polyimide film used for COF is relatively thick, there is a problem that it is inferior in solder heat resistance, particularly moisture-absorbing solder heat resistance.
JP-A-5-222219 JP-A-6-32926 Japanese Patent Laid-Open No. 11-158276 JP 2000-80178 A JP 2000-119521 A

  This invention is made in view of said subject, Comprising: The problem which the base material for conventional single-sided metal-clad laminates has is solved, and the adhesiveness between high heat resistant polyimide and adhesive polyimide is improved Another object is to provide a single-sided metal-clad laminate base material with improved solder heat resistance and a method for producing a single-sided metal-clad laminate using the single-sided metal-clad laminate substrate.

  As a result of intensive studies in view of the above-described problems, the present inventors have found that a single-sided metal-clad laminate base material that can solve various conventional problems, and a single-sided metal-clad laminate using the single-sided metal-clad laminate base material. A unique method for producing a laminated board was found, and the present invention was completed. That is, the present invention can solve the above problems by the following novel means.

  That is, the present invention is a substrate for a single-sided metal-clad laminate in which an adhesive polyimide layer is provided on one side of both surfaces of a high heat-resistant polyimide film and a non-adhesive polyimide layer is provided on the other side, The high heat-resistant polyimide film contains a thermoplastic polyimide block component in an amount of 20 to 60 mol% of the entire polyimide, and relates to a single-sided metal-clad laminate.

  In a preferred embodiment, the base for a single-sided metal-clad laminate is characterized in that 2,2-bis (4-aminophenoxyphenyl) propane is used as an essential component as a diamine component constituting the thermoplastic polyimide block component. Regarding materials.

  In a more preferred embodiment, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic acid is used as an acid component constituting the block component of the thermoplastic polyimide. Said single-sided metal-clad laminate, characterized in that at least one acid dianhydride selected from the group consisting of acid dianhydride and 4,4'-oxydiphthalic dianhydride is used as an essential component. About.

  A further preferred embodiment relates to the substrate for a single-sided metal-clad laminate, wherein the repeating unit n of the thermoplastic polyimide block component is 3 to 99.

  A further preferred embodiment relates to the substrate for a single-sided metal-clad laminate, wherein the repeating unit n of the thermoplastic polyimide block component is 4 to 90.

  Another aspect of the present invention is a method for producing a single-sided metal-clad laminate, in which a single-sided metal-clad laminate is produced by laminating a substrate for a single-sided metal-clad laminate and a metal foil. The substrate for use is a substrate for a single-sided metal-clad laminate in which an adhesive polyimide layer is provided on one side of both sides of a high heat-resistant polyimide film and a non-adhesive polyimide layer is provided on the other side, and the high heat resistance The present invention relates to a method for producing a single-sided metal-clad laminate, wherein the conductive polyimide film contains a thermoplastic polyimide block component in an amount of 20 to 60 mol% of the whole polyimide.

  According to the present invention, the substrate for a single-sided metal-clad laminate having improved solder heat resistance while improving the adhesion between the high heat-resistant polyimide and the adhesive polyimide, and the single-sided metal-clad laminate It becomes possible to provide a method for producing a single-sided metal-clad laminate using a base material for use.

  Embodiments of the present invention will be described below.

  The substrate for a single-sided metal-clad laminate according to the present invention is a substrate for a single-sided metal-clad laminate in which at least an adhesive layer and a non-adhesive layer are provided on both sides of a highly heat-resistant polyimide film, The polyimide film is characterized by containing a thermoplastic polyimide block component in an amount of 20 to 60 mol% of the whole polyimide.

  The method for producing a single-sided metal-clad laminate according to the present invention is a method for producing a single-sided metal-clad laminate by laminating a substrate for a single-sided metal-clad laminate and a metal foil. The substrate for a plate is a substrate for a single-sided metal-clad laminate in which at least an adhesive layer and a non-adhesive layer are provided on both sides of a high heat resistant polyimide film, and the high heat resistant polyimide film is a thermoplastic polyimide block component Is characterized by containing 20 to 60 mol% of the whole polyimide.

  By using the single-sided metal-clad laminate base material having such a configuration, it has been found that the moisture-absorbing solder heat resistance is improved and has found the present invention. The reason for this has not been clarified yet, but is presumed as follows. Defects in the moisture absorption solder heat resistance test, that is, whitening and foaming, are caused by rapid expansion at the interface between the metal foil and the polyimide layer when the moisture absorbed in the polyimide layer is immersed in a heated solder bath. This is a phenomenon that occurs. By introducing a thermoplastic polyimide block component into the high heat resistant polyimide layer, the water vapor transmission rate is remarkably improved, thereby preventing rapid expansion of moisture at the interface between the metal foil and the polyimide layer. .

  Hereinafter, description will be given based on an example of the embodiment.

<High heat resistant polyimide layer>
The high heat resistant polyimide film according to the present invention is manufactured using polyamic acid as a precursor. Any known method can be used as a method for producing the polyamic acid. Usually, the polyamic acid obtained by dissolving a substantially equimolar amount of an aromatic dianhydride and an aromatic diamine in an organic solvent is obtained. The organic solvent solution is produced by stirring under controlled temperature conditions until the polymerization of the acid dianhydride and the diamine is completed. These polyamic acid solutions are usually obtained at a concentration of 5 to 35% by weight, preferably 10 to 30% by weight. When the concentration is in this range, an appropriate molecular weight and solution viscosity are obtained.

As the polymerization method, any known method and a combination thereof can be used. The characteristic of the polymerization method in the polymerization of polyamic acid is the order of addition of the monomers, and various physical properties of the polyimide obtained can be controlled by controlling the order of addition of the monomers. Therefore, in the present invention, any method of adding monomers may be used for the polymerization of polyamic acid. The following method is mentioned as a typical polymerization method. That is,
1) A method in which an aromatic diamine is dissolved in an organic polar solvent, and this is reacted with a substantially equimolar aromatic tetracarboxylic dianhydride for polymerization.
2) An aromatic tetracarboxylic dianhydride is reacted with a small molar amount of an aromatic diamine compound in an organic polar solvent to obtain a prepolymer having acid anhydride groups at both ends. Subsequently, a method of polymerizing with an aromatic diamine compound so that the aromatic tetracarboxylic dianhydride and the aromatic diamine compound are substantially equimolar in all steps,
3) An aromatic tetracarboxylic dianhydride is reacted with an excess molar amount of an aromatic diamine compound in an organic polar solvent to obtain a prepolymer having amino groups at both ends. Subsequently, after adding an aromatic diamine compound here, using the aromatic tetracarboxylic dianhydride so that the aromatic tetracarboxylic dianhydride and the aromatic diamine compound are substantially equimolar in all steps. How to polymerize,
4) A method in which an aromatic tetracarboxylic dianhydride is dissolved and / or dispersed in an organic polar solvent and then polymerized using an aromatic diamine compound so as to be substantially equimolar,
5) A method of polymerizing by reacting a mixture of substantially equimolar aromatic tetracarboxylic dianhydride and aromatic diamine in an organic polar solvent,
And so on. These methods may be used singly or in combination.

  The high heat-resistant polyimide film of the present invention must contain 20 to 60 mol% of a thermoplastic polyimide block component in the molecule. For the purpose of ideally forming the block component, after forming the block component of the thermoplastic polyimide precursor, the method of forming the non-thermoplastic polyimide precursor using the remaining diamine and / or acid dianhydride is used. preferable. Under the present circumstances, it is preferable to use combining the method of said 1) -5) partially.

  In the present invention, the thermoplastic polyimide block component refers to a component that melts when the high molecular weight film is heated to about 350 ° C. to 500 ° C. and does not retain the shape of the film. As a more specific determination method for the thermoplastic polyimide block component, the molar ratio of the diamine to be used and the acid dianhydride is added to an appropriate solvent so that the molar ratio is virtually 100: 97 to 97: 100. A solution is prepared, and then the polyamic acid solution is coated on a smooth support so that the final thickness is 10 to 30 μm and the length of one side is 25 cm or more. Specific examples of the smooth support include PET film, aluminum foil, and copper foil. Examples of the method for applying the final thickness to 10 to 30 μm include a bar coater, a comma coater, and a doctor blade. Furthermore, the coating film of the polyamic acid solution coated on the support is dried until it is self-supporting, peeled off from the support, fixed to a metal frame, and imidization and drying are substantially terminated. To produce a single layer sheet of polyimide. Examples of the drying and imidization methods include hot air and far infrared rays, and the temperature conditions are appropriately selected depending on the solvent species and the molecular structure of the polyamic acid. The polyimide single-layer sheet thus obtained was fixed to a square metal frame having an inner side of 20 cm each so that the center of the polyimide single-layer sheet and the metal frame substantially coincided, and 350 ° C. to 500 ° C. In the atmosphere of 5 minutes or more so that the film is substantially horizontal. At that time, if the center of the film is thermally deformed by 1 cm or more vertically downward, the block component made of the polyimide is determined to be thermoplastic.

  The melting temperature is further preferably 250 to 450 ° C, particularly preferably 300 to 400 ° C. If this temperature is too low, it will be difficult to finally obtain a highly heat-resistant polyimide film. If this temperature is too high, it will be difficult to obtain excellent adhesion, which is an effect of the present invention.

  Furthermore, the thermoplastic polyimide block component is contained in an amount of 20 to 60 mol%, preferably 25 to 55 mol%, particularly preferably 30 to 50 mol% of the whole polyimide.

  If the thermoplastic polyimide block component is less than this range, it becomes difficult to develop the excellent adhesiveness of the present invention at the same time as the moisture absorption solder heat resistance is deteriorated. It becomes difficult.

  Here, the mol% of the thermoplastic polyimide block component, that is, the content of the thermoplastic polyimide block component in the present invention was synthesized by using the thermoplastic polyimide block component excessively with respect to the acid component. In the case of synthesis by the following calculation formula (1), the acid component is calculated according to the following calculation formula (2) when synthesized in excess with respect to the diamine component.

(Thermoplastic polyimide block component content) = a / b × 100 Formula (1)
a: Amount of diamine contained in thermoplastic polyimide block component (mol)
b: Total diamine amount (mol)
(Thermoplastic polyimide block component content) = a / b × 100 Formula (2)
a: Amount of acid component (mol) contained in thermoplastic polyimide block component
b: Total acid component amount (mol)
Further, the repeating unit n of the thermoplastic polyimide block component is preferably 3 to 99, more preferably 4 to 90. When the repeating unit n is less than this range, excellent adhesiveness is hardly exhibited and the hygroscopic expansion coefficient tends to increase. On the other hand, if the repeating unit n exceeds this range, the storage stability of the polyimide precursor solution tends to deteriorate, and the reproducibility of polymerization tends to decrease, such being undesirable.

  The thermoplastic polyimide block component in the present invention preferably has a glass transition temperature (Tg) in the range of 150 to 300 ° C. in the high molecular weight body. Tg can be obtained from the inflection point value of the storage elastic modulus measured by a dynamic viscoelasticity measuring device (DMA).

The monomer that forms the thermoplastic polyimide block component of the present invention will be described.
Examples that can be preferably used as the diamine main component constituting the thermoplastic polyimide block component of the present invention include 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 3,3. '-Diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 4,4'-oxydianiline, 3,3'-oxydianiline, 3,4'-oxydianiline, 4,4'-diaminodiphenyldiethyl Silane, 4,4′-diaminodiphenylsilane, 4,4′-diaminodiphenylethylphosphine oxide, 4,4′-diaminodiphenyl N-methylamine, 4,4′-diaminodiphenyl N-phenylamine, 1,4- Diaminobenzene (p-phenylenediamine), bis {4- (4-aminophenoxy) Enyl} sulfone, 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, Examples include 3′-diaminobenzophenone, 4,4′-diaminobenzophenone, 2,2-bis (4-aminophenoxyphenyl) propane, and these can be used alone or in combination. These examples are examples that are suitably used as the main component, and any diamine can be used as the accessory component. Examples of diamines that can be particularly preferably used among these are 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 1,3-bis (3-amino). Phenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 2,2-bis (4 -Aminophenoxyphenyl) propane.

  Among these, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride is particularly preferable because the adhesiveness can be easily controlled within a suitable range.

  Examples that can be suitably used as the acid component constituting the thermoplastic polyimide block component include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride and the like can be mentioned, and these can be used alone or in combination. In the present invention, at least 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4,4′-oxydiphthalic acid It is preferable to use at least one acid dianhydride selected from the group consisting of anhydrides as an essential component. By using these acid dianhydrides, high adhesion to the adhesive polyimide layer, which is the effect of the present invention, can be easily obtained.

  In this invention, the suitable example of the diamine and acid dianhydride used when making it react with a thermoplastic polyimide block component (in this stage, a thermoplastic polyimide precursor block component) and manufacturing a highly heat-resistant polyimide precursor is used. I will give you. Although various characteristics change depending on the combination of diamine and acid dianhydride, it cannot be specified unconditionally, but ultimately, a diamine and an acid that form a highly heat-resistant polyimide are used. As such a diamine, it is preferable to use a rigid component such as paraphenylenediamine and a derivative thereof, benzidine and a derivative thereof as a main component. By using these diamines having a rigid structure, it becomes non-thermoplastic and it is easy to achieve a high elastic modulus. Moreover, it is preferable to use pyromellitic dianhydride as a main component as an acid component. As is well known, pyromellitic dianhydride tends to give a non-thermoplastic polyimide because of its rigid structure.

  Here, the high heat-resistant polyimide film in the present invention refers to a film that melts and maintains the shape of the film when the high molecular weight film is heated to about 350 ° C. to 500 ° C. As a more specific method for determining a high heat-resistant polyimide film, the molar ratio of the diamine to be used and the acid dianhydride is added to an appropriate solvent so that it is virtually 100: 97 to 97: 100, and polyamic acid is added. A solution is prepared, and then the polyamic acid solution is coated on a smooth support so that the final thickness is 10 to 30 μm and the length of one side is 25 cm or more. Specific examples of the smooth support include PET film, aluminum foil, and copper foil. Examples of the method for applying the final thickness to 10 to 30 μm include a bar coater, a comma coater, and a doctor blade. Furthermore, the coating film of the polyamic acid solution coated on the support is dried until it is self-supporting, peeled off from the support, fixed to a metal frame, and imidization and drying are substantially terminated. To produce a single layer sheet of polyimide. Examples of the drying and imidization methods include hot air and far infrared rays, and the temperature conditions are appropriately selected depending on the solvent species and the molecular structure of the polyamic acid. The polyimide single-layer sheet thus obtained was fixed to a square metal frame having an inner side of 20 cm each so that the center of the polyimide single-layer sheet and the metal frame substantially coincided, and 350 ° C. to 500 ° C. In the atmosphere of 5 minutes or more so that the film is substantially horizontal. At that time, if the thermal deformation at the center of the film is less than 1 cm in the vertically downward direction, the film made of the polyimide is determined to have high heat resistance.

  In the present invention, from the viewpoint of ease of polymerization control and convenience of the apparatus, first, a thermoplastic polyimide precursor block component is synthesized, and then diamine and acid dianhydride are added at an appropriately designed molar fraction to achieve high heat resistance. It is preferable to use a polymerization method using a conductive polyimide precursor.

  As a preferred solvent for synthesizing a polyimide precursor (hereinafter referred to as polyamic acid), any solvent that dissolves polyamic acid can be used, but amide solvents, that is, N, N-dimethylformamide, N, N -Dimethylacetamide, N-methyl-2-pyrrolidone and the like, and N, N-dimethylformamide and N, N-dimethylacetamide can be particularly preferably used.

  In addition, a filler can be added for the purpose of improving various film properties such as slidability, thermal conductivity, conductivity, corona resistance, and loop stiffness. Any filler may be used, but preferred examples include silica, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, mica and the like.

The particle size of the filler is not particularly limited because it is determined by the film characteristics to be modified and the kind of filler to be added, but generally the average particle size is 0.05 to 100 μm, preferably 0.1. It is -75 micrometers, More preferably, it is 0.1-50 micrometers, Most preferably, it is 0.1-25 micrometers. If the particle size is below this range, the modification effect is less likely to appear. If the particle size is above this range, the surface properties may be greatly impaired or the mechanical properties may be greatly deteriorated. Further, the number of added parts of the filler is not particularly limited because it is determined by the film properties to be modified, the filler particle diameter, and the like. Generally, the addition amount of the filler is 0.01 to 100 parts by weight, preferably 0.01 to 90 parts by weight, and more preferably 0.02 to 80 parts by weight with respect to 100 parts by weight of the polyimide. If the amount of filler added is less than this range, the effect of modification by the filler hardly appears, and if it exceeds this range, the mechanical properties of the film may be greatly impaired. Addition of filler
1. 1. A method of adding to a polymerization reaction solution before or during polymerization 2. A method of kneading fillers using three rolls after the completion of polymerization. Any method such as preparing a dispersion containing filler and mixing it with a polyamic acid organic solvent solution may be used, but a method of mixing a dispersion containing filler with a polyamic acid solution, particularly immediately before film formation. This method is preferable because the contamination by the filler in the production line is minimized. When preparing a dispersion containing a filler, it is preferable to use the same solvent as the polymerization solvent for the polyamic acid. Further, in order to disperse the filler satisfactorily and stabilize the dispersion state, a dispersant, a thickener and the like can be used within a range not affecting the film physical properties.

  A conventionally well-known method can be used about the method of manufacturing a polyimide film from these polyamic-acid solutions. This method includes a thermal imidization method and a chemical imidization method, and either method may be used to produce a film, but the imidization by the chemical imidation method is more preferably used in the present invention. It tends to be easy to obtain a polyimide film having various characteristics.

In addition, the production process of the polyimide film particularly preferable in the present invention is as follows.
a) reacting an aromatic diamine and an aromatic tetracarboxylic dianhydride in an organic solvent to obtain a polyamic acid solution;
b) casting a film-forming dope containing the polyamic acid solution on a support;
c) a step of peeling the gel film from the support after heating on the support;
d) further heating to imidize and dry the remaining amic acid,
It is preferable to contain.

  In the above step, a curing agent containing a dehydrating agent typified by an acid anhydride such as acetic anhydride and an imidation catalyst typified by a tertiary amine such as isoquinoline, β-picoline or pyridine may be used. .

  The thickness of the highly heat-resistant polyimide film according to the present invention is not particularly limited, but considering the use of the finally obtained single-sided metal-clad laminate, it is 15 to 50 μm, preferably 20 to 45 μm, particularly preferably 20 ˜40 μm.

  In the following, a preferred embodiment of the present invention, the chemical imide method, is taken as an example to describe the process for producing a polyimide film. However, the present invention is not limited to the following examples.

  The film forming conditions and heating conditions can vary depending on the type of polyamic acid, the thickness of the film, and the like.

A film forming dope is obtained by mixing a dehydrating agent and an imidization catalyst in a polyamic acid solution at a low temperature. Subsequently, this film-forming dope is cast into a film on a support such as a glass plate, an aluminum foil, an endless stainless steel belt, or a stainless drum, and the temperature on the support is 80 ° C. to 200 ° C., preferably 100 ° C. to 180 ° C. By heating in the region, the dehydrating agent and imidization catalyst are activated to partially cure and / or dry and then peel from the support to obtain a polyamic acid film (hereinafter referred to as a gel film).
The gel film is in the intermediate stage of curing from polyamic acid to polyimide, has a self-supporting property, and has the following formula (3)
(A−B) × 100 / B (Equation 3)
(However, in Formula (3), A and B represent the following.
A: Weight of the gel film B: Weight after heating the gel film at 450 ° C. for 20 minutes)
The volatile content calculated from is in the range of 5 to 500% by weight, preferably 5 to 200% by weight, more preferably 5 to 150% by weight. It is preferable to use a film in this range, and problems such as film breakage, uneven film color due to drying unevenness, and characteristic variations may occur during the baking process.

  The preferable amount of the dehydrating agent is 0.5 to 5 mol, preferably 1.0 to 4 mol, relative to 1 mol of the amic acid unit in the polyamic acid.

  Moreover, the preferable quantity of an imidation catalyst is 0.05-3 mol with respect to 1 mol of amic acid units in a polyamic acid, Preferably it is 0.2-2 mol.

  If the dehydrating agent and the imidization catalyst are below the above ranges, chemical imidization may be insufficient, and may break during firing or mechanical strength may decrease. Moreover, when these amounts exceed the above range, the progress of imidization becomes too fast, and it may be difficult to cast into a film, which is not preferable.

  The end of the gel film is fixed to avoid shrinkage during curing, water, residual solvent, residual conversion agent and catalyst are removed, and the remaining amic acid is completely imidized to obtain the present invention. A polyimide film is obtained.

  At this time, it is preferable to finally heat at a temperature of 400 to 650 ° C. for 5 to 400 seconds. Above this temperature and / or for a long time, the film may suffer from thermal degradation and may cause problems. Conversely, if the temperature is lower than this temperature and / or the time is shorter, the predetermined effect may not be exhibited.

  Moreover, in order to relieve the internal stress remaining in the film, heat treatment can be performed under the minimum tension necessary for transporting the film. This heat treatment may be performed in the film manufacturing process, or may be provided separately. The heating conditions vary depending on the characteristics of the film and the apparatus used, and therefore cannot be determined in general. The internal stress can be relaxed by heat treatment at a temperature of 450 ° C. or lower for 1 to 300 seconds, preferably 2 to 250 seconds, particularly preferably 5 to 200 seconds.

<Adhesive polyimide layer>
The adhesive polyimide layer referred to in the present invention contains a thermoplastic polyimide resin, and a single layer sheet of 250 mm × 250 mm consisting only of the adhesive polyimide layer is sandwiched between 12 μm electrolytic copper foils, and 360 by a hot roll laminator. When the CCL is produced by pressure bonding at 0 ° C., a pressure between rolls of 0.6 t, and a linear velocity of 1.5 m / min, the peel strength of the metal foil is 5 N / cm or more. For the peel strength of the metal foil, a sample was prepared in accordance with “6.5 peel strength” of JIS C6471, and a 5 mm wide metal foil portion was peeled off at a peeling angle of 180 degrees and 50 mm / min. Refers to the load per unit width.

  The adhesive polyimide layer according to the present invention has a thermoplastic polyimide resin content and molecular structure contained in the layer as long as desired properties such as a significant adhesive force with a conductor and a suitable linear expansion coefficient are expressed. The thickness is not particularly limited. However, it is preferable that substantially 80% by weight or more of the thermoplastic polyimide resin is substantially contained in order to exhibit desired properties such as a significant adhesive force and a suitable linear expansion coefficient.

  As the thermoplastic polyimide contained in the adhesive polyimide layer, thermoplastic polyimide, thermoplastic polyamideimide, thermoplastic polyetherimide, thermoplastic polyesterimide, and the like can be suitably used. Among these, thermoplastic polyesterimide is particularly preferably used from the viewpoint of low moisture absorption characteristics.

  The thermoplastic polyimide contained in the adhesive polyimide layer according to the present invention is obtained by a conversion reaction from the precursor polyamic acid. As the method for producing the polyamic acid, any known method can be used as in the precursor of the high heat resistant polyimide layer.

  Further, considering that it exhibits a significant adhesive force with the conductor layer and does not impair the heat resistance of the resulting metal-clad laminate, the thermoplastic polyimide in the present invention is glass in the range of 150 to 300 ° C. It preferably has a transition temperature (Tg). In addition, Tg can be calculated | required from the value of the inflexion point of the storage elastic modulus measured with the dynamic viscoelasticity measuring apparatus (DMA).

  The properties of the thermoplastic polyimide can be controlled by combining various raw materials used. As a specific example, various characteristics can be controlled by adjusting the ratio of a rigid structure diamine and a flexible structure diamine.

  When the ratio of the rigid structure diamine used is increased, the glass transition temperature is increased and / or the storage elastic modulus at the time of heating is increased, and the adhesiveness and workability are decreased. The diamine ratio of the rigid structure is preferably 40 mol% or less, more preferably 30 mol% or less, and particularly preferably 20 mol% or less.

  The diamine having the rigid structure is represented by the following general formula (1)

（ただし、式中のＲ_２は下記一般式群（１）

(In the formula, R ₂ represents the following general formula group (1)

で表される２価の芳香族基からなる群から選択される何れかの１つの基であり、式中のＲ_３は同一または異なってＨ−，ＣＨ_３−、−ＯＨ、−ＣＦ_３、−ＳＯ_４、−ＣＯＯＨ、−ＣＯ-ＮＨ_２、Ｃｌ−、Ｂｒ−、Ｆ−、及びＣＨ_３Ｏ−からなる群より選択される何れかの１つの基である）
で表されるものをいう。

Any one group selected from the group consisting of divalent aromatic groups represented by: wherein R ₃ is the same or different and is H—, CH ₃ —, —OH, —CF ₃ , _{-SO 4, -COOH, -CO-NH} 2, Cl-, Br-, F-, and _CH 3 is any one group selected from the group consisting of O-)
The one represented by

  The diamine having a flexible structure is a diamine having a flexible structure such as an ether group, a sulfone group, a ketone group, or a sulfide group, and is preferably represented by the following general formula (2).

（式中のＲ_４は、下記一般式群（２）で表される群から選択される何れかの１つの基である。）

(R ₄ in the formula is any one group selected from the group represented by the following general formula group (2).)

好ましい熱可塑性ポリイミド樹脂の具体例としては、ビフェニルテトラカルボン酸二無水物類を含む酸二無水物とアミノフェノキシ基を有するジアミンを重合反応せしめたものが挙げられる。

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

  Furthermore, for the purpose of controlling the properties of the single-sided metal-clad laminate according to the present invention, inorganic or organic fillers and other resins may be added as necessary.

<Non-adhesive polyimide layer>
The non-adhesive polyimide layer in the present invention refers to a layer that does not exhibit a significant adhesive force to a roll, a belt, a protective film or the like during lamination. Specifically, a 250 mm × 250 mm single layer sheet consisting only of the non-adhesive polyimide layer is sandwiched between 12 μm electrolytic copper foils, 360 ° C. with a hot roll laminator, a pressure between rolls of 0.6 t, and a linear velocity of 1.5 m. When the CCL is produced by pressure bonding at / min, the peel strength of the metal foil is 2 N / cm or less. For the peel strength of the metal foil, a sample was prepared in accordance with “6.5 peel strength” of JIS C6471, and a 5 mm wide metal foil portion was peeled off at a peeling angle of 180 degrees and 50 mm / min. Refers to the load per unit width.

  The content, molecular structure, and thickness of the polyimide resin contained in the non-adhesive polyimide layer are not particularly limited as long as desired characteristics such as a suitable linear expansion coefficient and non-adhesiveness are expressed. However, considering heat resistance, it is desirable that the polyimide resin contained in the layer is 60% by weight or more, preferably 80% by weight or more. Moreover, in order to obtain a desired characteristic, you may mix a non-thermoplastic polyimide resin and / or a thermoplastic resin.

  As a characteristic required for the non-adhesive polyimide layer, in order to prevent curling and warping of the single-sided metal-clad laminate, it is desirable to have a thermal expansion coefficient substantially equal to that of the adhesive polyimide layer. In general, the thermoplastic polyimide resin that is the main component of the adhesive polyimide layer has a coefficient of thermal expansion of about 40 to 100 ppm / ° C. Therefore, the coefficient of thermal expansion of the non-adhesive polyimide layer is 40 to 100 ppm / ° C, preferably It is preferable that it is 50-90 ppm / degreeC. Here, the thermal expansion coefficient can be measured using, for example, TMA120C manufactured by Seiko Electronics Co., Ltd., and the temperature is once raised from 10 ° C. to 400 ° C. at 10 ° C./min with a sample size of 3 mm in width, 10 mm in length, and 3 g of load. Then, it is cooled to 10 ° C., further heated at 10 ° C./min, and calculated as an average value from the coefficient of thermal expansion from 100 ° C. to 200 ° C. during the second temperature increase.

On the other hand, it is important not to be extremely softened at the laminating temperature in order not to exhibit a significant adhesive force during laminating. In general, since lamination is often performed at a temperature around 350 ° C., the elastic modulus at 350 ° C. is extremely important, and the elastic modulus is 1 × 10 ⁸ Pa or more, preferably 5 × 10 ⁸ Pa or more. It is desirable. The elastic modulus at 350 ° C. can be measured using, for example, DMS200 manufactured by Seiko Electronics Co., Ltd., and the sample size is 9 mm wide, 40 mm long, frequencies 1, 5, and 10 Hz, and a heating rate of 3 ° C./min and 20 to 400. It is a value at 350 ° C when measured in the temperature range of ° C.

  The polyimide contained in the non-adhesive polyimide layer according to the present invention is obtained by a conversion reaction from the precursor polyamic acid. As the method for producing the polyamic acid, any known method can be used as in the precursor of the high heat resistant polyimide layer.

  Furthermore, for the purpose of controlling the properties of the single-sided copper-clad laminate substrate according to the present invention, inorganic or organic fillers and other resins may be added as necessary.

<Manufacture of single-sided metal-clad laminate base material>
As a method for obtaining a substrate for a single-sided metal-clad laminate according to the present invention, any conventionally known method may be used. After producing a single-layer film for each layer, or after producing a single-layer film. Examples thereof include a method of applying and drying a polyimide precursor solution or a polyimide solution for constructing another layer, and imidizing as necessary.

<Manufacture of single-sided metal-clad laminate>
The manufacturing method of the single-sided metal-clad laminate according to the present invention may be any conventionally known method as long as it is a laminating method, and is a method using a double belt device or heating and pressurizing with one or more pairs of hot rolls. A method is illustrated. In addition, a method of sandwiching a protective film between a metal body such as a metal belt of a double belt or a metal roll of a heat roll and a single-sided metal-clad laminate, or a method of filling at least a part of the apparatus with an inert gas such as nitrogen is also preferable. Used.

Next, the manufacturing method of the adhesive film which concerns on this invention is demonstrated in detail by an Example.

  In addition, the evaluation method of the various characteristics in a synthesis example, an Example, and a comparative example is as follows.

(Hygroscopic solder heat resistance)
The single-sided metal-clad laminate was moisture-absorbed for 96 hours under a humidified condition of 85 ° C. and 85% RH, then immersed in a solder bath at 280 ° C. for 10 seconds, and swelling and whitening were visually determined.

(Dimensional change rate)
Based on JIS C6481, four holes were formed in the single-sided metal-clad laminate, and the distance of each hole was measured. Next, after carrying out an etching process to remove the metal foil from the flexible laminate, it was left in a temperature-controlled room at 20 ° C. and 60% RH for 24 hours. Then, each distance was measured about the said four holes similarly to the etching process front. The measured value of the distance of each hole before metal foil removal was set to D1, and the measured value of the distance of each hole before metal foil removal was set to D2, and the dimensional change rate was calculated | required by following Formula.
Dimensional change rate (%) = {(D2-D1) / D1} × 100
In addition, the said dimensional change rate was measured about both MD direction and TD direction.

  Subsequently, the measurement sample after etching was heated at 250 ° C. for 30 minutes and then left in a constant temperature room at 20 ° C. and 60% RH for 24 hours. Then, each distance was measured about the said four holes. The measured value of the distance of each hole after heating was set to D3, and the dimensional change rate before and after heating was obtained by the following formula.

Dimensional change rate (%) = {(D3-D2) / D2} × 100
In addition, the said dimensional change rate was measured about both MD direction and TD direction.

(Stripping strength of metal foil: Adhesive strength)
A sample was prepared according to “6.5 Peel Strength” of JIS C6471, and a 5 mm wide metal foil part was peeled off at a peeling angle of 180 degrees and 50 mm / min, and the load was measured.

(Measurement of thermal elastic modulus)
Using a DMS200 manufactured by Seiko Electronics Co., Ltd. (sample size: 9 mm wide, 40 mm long), measured at a frequency of 1, 5 and 10 Hz at a temperature rising rate of 3 ° C./min in a temperature range of 20 to 400 ° C., 350 ° C. I read the value at.

(Thermal expansion coefficient)
The measurement of the coefficient of thermal expansion was carried out using a TMA120C manufactured by Seiko Electronics Co., Ltd. (sample size width 3 mm, length 10 mm), and once heated from 10 ° C. to 400 ° C. at 10 ° C./min with a load of 3 g, After cooling to 10 ° C., the temperature was further increased at 10 ° C./min, and the average value was calculated from the coefficient of thermal expansion from 100 ° C. to 200 ° C. during the second temperature increase.

(Solution storage stability)
The storage stability of the polyimide precursor solution was determined visually by storing the prepared solution in a refrigerator at 5 ° C. for 1 month.

(Synthesis Example 1: Synthesis of polyamide acid precursor of thermoplastic polyimide)
780 g of dimethylformamide (DMF) and 115.6 g of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) were added to a glass flask having a capacity of 2000 ml and stirred under a nitrogen atmosphere. , 3'4,4'-biphenyltetracarboxylic dianhydride (BPDA) was gradually added. Subsequently, 3.8 g of ethylenebis (trimellitic acid monoester acid anhydride) (TMEG) was added and stirred for 30 minutes in an ice bath. A solution in which 2.0 g of TMEG was dissolved in 20 g of DMF was separately prepared, and this was gradually added to the reaction solution while being careful of the viscosity and stirred. When the viscosity reached 3000 poise, addition and stirring were stopped to obtain a polyamic acid solution.

  This polyamic acid solution was cast on a 25 μm PET film (Therapy HP, manufactured by Toyo Metallizing Co., Ltd.) so as to have a final thickness of 20 μm, and dried at 120 ° C. for 5 minutes. After peeling off the dried self-supporting film from PET, it is fixed to a metal pin frame and dried at 150 ° C. for 5 minutes, 200 ° C. for 5 minutes, 250 ° C. for 5 minutes, 350 ° C. for 5 minutes, A single layer sheet was obtained. The glass transition temperature of this thermoplastic polyimide was 240 ° C. Moreover, when this film was fixed to the metal frame and it heated at 450 degreeC, it turned out that a form is not hold | maintained but it is thermoplastic.

  Further, when the thermal elastic modulus and the thermal linear expansion coefficient at 350 ° C. were measured, the thermal elastic modulus was broken at 320 ° C. and could not be measured, and the linear expansion coefficient was 67 ppm / ° C.

(Synthesis Example 2: Synthesis of Polyamide Acid as Polyimide Precursor for Non-adhesive Polyimide Layer)
Add 795 g of DMF and 88.5 g of 4,4′-oxydianiline (ODA) to a glass flask with a capacity of 2000 ml, and gradually add 94.5 g of pyromellitic dianhydride (PMDA) while stirring under a nitrogen atmosphere. And stirred for 30 minutes in an ice bath. A solution in which 1.9 g of PMDA was dissolved in 20 g of DMF was separately prepared, and this was gradually added to the reaction solution while being careful of the viscosity and stirred. When the viscosity reached 3000 poise, addition and stirring were stopped to obtain a polyamic acid solution.

  The polyamic acid solution prepared by the above-mentioned means and the polyamic acid solution obtained in Synthesis Example 1 are mixed at a weight ratio of 85:15, and uniformly stirred for 30 minutes in a nitrogen atmosphere, so that the precursor of the polyimide for the non-adhesive layer is obtained. Got the body.

  This polyamic acid solution was cast on a 25 μm PET film (Therapy HP, manufactured by Toyo Metallizing Co., Ltd.) so as to have a final thickness of 20 μm, and dried at 120 ° C. for 5 minutes. After peeling off the dried self-supporting film from PET, it is fixed to a metal pin frame and dried at 150 ° C. for 5 minutes, 200 ° C. for 5 minutes, 250 ° C. for 5 minutes, 350 ° C. for 5 minutes, A single layer sheet was obtained.

  This single layer sheet was cut into 250 mm × 250 mm, and passed through a hot roll set at 360 ° C. and a pressure between rolls of 0.6 t at a linear velocity of 1.5 m / min. It could be easily peeled off from the hot roll, and no contamination was left on the hot roll surface.

Moreover, it was 4 * 10 < ⁸ > Pa and 60 ppm / degrees C when the elastic modulus at heat in 350 degreeC and a thermal linear expansion coefficient were measured.

(Example 1)
In 546 g of N, N-dimethylformamide (DMF) cooled to 10 ° C., 46.43 g of 2,2-bis (4-aminophenoxyphenyl) propane (BAPP) was dissolved. To this, 9.12 g of 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA) was added and dissolved, and then 16.06 g of pyromellitic dianhydride (PMDA) was added. The mixture was stirred for 30 minutes to form a thermoplastic polyimide precursor block component.
After dissolving 18.37 g of p-phenylenediamine (p-PDA) in this solution, 37.67 g of PMDA was added and stirred for 1 hour to dissolve. Further, a DMF solution of PMDA (PMDA 1.85 g / DMF 24.6 g) prepared separately was carefully added to this solution, and the addition was stopped when the viscosity reached about 3000 poise. Stirring was performed for 1 hour to obtain a polyamic acid solution having a solid content of about 19% by weight and a rotational viscosity at 23 ° C. of 3400 poise.

  To 100 g of this polyamic acid solution, 50 g of a curing agent composed of acetic anhydride / isoquinoline / DMF (weight ratio 18.90 / 7.17 / 18.93) was added, and the mixture was stirred and degassed at a temperature of 0 ° C. or less to obtain a comma. Using a coater, it was cast on aluminum foil. This resin film is heated at 130 ° C. for 100 seconds, and then the self-supporting gel film is peeled off from the aluminum foil (volatile content 45% by weight) and fixed on a metal frame, 300 ° C. × 20 seconds, 450 ° C. × 20 Second and dried at 500 ° C. for 20 seconds and imidized to obtain a high heat-resistant polyimide film having a thickness of 35 μm.

  The polyamic acid solution obtained at a ratio of BAPP / BTDA / PMDA = 46.43 g / 9.12 g / 18.53 g was tried to be formed into a film in the same manner, but melted at a heating stage of 450 ° C. to maintain the form. It was confirmed that it was thermoplastic.

  After diluting the polyamic acid solution of the precursor of thermoplastic polyimide obtained in Synthesis Example 1 with DMF until the solid content concentration becomes 10% by weight, a thermoplastic polyimide layer (adhesion) is formed on one surface of the high heat resistant polyimide film. The polyamic acid was applied so that the final single-sided thickness of the layer was 6 μm, and then heated at 140 ° C. for 1 minute. Subsequently, after the polyamic acid solution of the polyimide precursor for the non-adhesive polyimide layer obtained in Synthesis Example 2 is diluted with DMF until the solid content concentration becomes 10% by weight, the solution and the imidization accelerator are used. 3,4-Lutidine was mixed at a weight ratio of 95: 5. The obtained solution was applied to the surface of the high heat-resistant polyimide film where the adhesive layer was not provided so that the final single-sided thickness of the non-adhesive layer was 6 μm, and heated at 140 ° C. for 1 minute. Subsequently, the imidation was performed by passing through a far infrared heater furnace having an atmospheric temperature of 390 ° C. for 20 seconds to obtain a substrate for a single-sided metal-clad laminate.

  18 μm rolled copper foil (BHY-22B-T manufactured by Japan Energy Co., Ltd.) was used on the adhesive layer side of the obtained single-sided metal-clad laminate substrate, and a protective material (manufactured by Kaneka: Apical 125 NPI) was used on the surface of the heat roll. Then, hot roll lamination was performed under the conditions of a lamination temperature of 360 ° C., a lamination pressure of 196 N / cm (20 kgf / cm), and a lamination speed of 1.5 m / min, to produce a single-sided metal-clad laminate.

  Table 1 shows the hygroscopic solder heat resistance, the dimensional change rate, the adhesive strength, and the storage stability of the precursor solution of the high heat-resistant polyimide of the obtained single-sided metal-clad laminate.

(Examples 2 and 3, Comparative Examples 1 and 2)
A high heat-resistant polyimide film was obtained in the same manner as in Example 1 by changing the monomer ratio, and a single-sided metal-clad laminate was produced using the same.

  Table 1 shows the hygroscopic solder heat resistance, the dimensional change rate, the adhesive strength, and the storage stability of the precursor solution of the high heat-resistant polyimide of the obtained single-sided metal-clad laminate.

In Comparative Example 1, the polyamic acid solution obtained at a ratio of PDA / PMDA = 23.0 g / 46.0 g was formed into a film and heated at 500 ° C. for 5 minutes. There wasn't. Therefore, Comparative Example 1 does not have a thermoplastic block component repetition length.
Similarly, in Comparative Example 2, a polyamic acid solution obtained at a ratio of PDA / BAPP / BTDA / PMDA = 9.4 g / 23.8 g / 4.7 g / 31.2 g was formed into a film and heated at 500 ° C. for 5 minutes. However, it was not thermoplastic because it was not thermally deformed. Therefore, Comparative Example 2 does not have a thermoplastic block component repetition length.

  As shown in the examples and comparative examples, the base material for the single-sided metal-clad laminate of the comparative example failed in the hygroscopic solder heat resistance test, and the dimensional change rate and adhesive strength may be greatly inferior compared to the examples. I understood.

Claims (6)

  A substrate for a single-sided metal-clad laminate in which an adhesive polyimide layer is provided on one side of both sides of a high heat-resistant polyimide film and a non-adhesive polyimide layer is provided on the other side, wherein the high-heat-resistant polyimide film is The base material for single-sided metal-clad laminates which contains a thermoplastic polyimide block component in an amount of 20 to 60 mol% of the whole polyimide.   The substrate for a single-sided metal-clad laminate according to claim 1, wherein 2,2-bis (4-aminophenoxyphenyl) propane is used as an essential component as a diamine component constituting the thermoplastic polyimide block component. .   3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4 as acid components constituting the block component of the thermoplastic polyimide The base material for a single-sided metal-clad laminate according to claim 1 or 2, wherein at least one acid dianhydride selected from the group consisting of 4,4'-oxydiphthalic dianhydride is used as an essential component. .   The base material for single-sided metal-clad laminates according to any one of claims 1 to 3, wherein the repeating unit n of the thermoplastic polyimide block component is 3 to 99.   The substrate for a single-sided metal-clad laminate according to any one of claims 1 to 3, wherein the repeating unit n of the thermoplastic polyimide block component is 4 to 90.   A method for producing a single-sided metal-clad laminate by laminating a single-sided metal-clad laminate and a metal foil, wherein the single-sided metal-clad laminate has a high heat resistance. A substrate for a single-sided metal-clad laminate in which an adhesive polyimide layer is provided on one side of a polyimide film and a non-adhesive polyimide layer is provided on the other side, and the high heat-resistant polyimide film is a thermoplastic polyimide. The manufacturing method of the single-sided metal-clad laminated board characterized by containing a block component 20-60 mol% of the whole polyimide.