JP2005068226A - Polyamide-imide resin, flexible metal-clad laminate and flexible printed wiring board using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polyamide-imide resin having excellent heat resistance, dimensional stability (low thermal expansion properties), low hygroscopicity, excellent insulation characteristic and low dielectric dissipation factor. <P>SOLUTION: The polyamide-imide resin comprises ≥90 mol% and ≤200 mol% of a biphenyl bond-containing monomer when the whole amount of an acid component is 100 mol%, the whole amount of an amine (isocyanate) component is 100 mol% and the total of the acid component and the amine (isocyanate) component is 200 mol%. Preferably, the molar ratio of the imide bond to the amide bond in the polyamide-imide resin is 75/25-55/45. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polyamide-imide resin, and more particularly, a non-halogen-based polyamide-imide resin having excellent heat resistance, dimensional stability, low hygroscopicity, excellent insulating properties, and low dielectric loss tangent, and the use thereof The present invention relates to a flexible metal-clad laminate and a flexible printed board using the same.

  In the present specification and claims, a “flexible metal-clad laminate” is a laminate formed from a metal foil and a resin layer, and is a laminate useful for the production of, for example, a flexible printed circuit board. . Here, the “flexible printed circuit board” means that, for example, a flexible metal-clad laminate can be produced by a conventionally known method such as a subtractive method, and a conductor circuit is partially or entirely covered by a coverlay film as necessary. And so-called flexible circuit boards (FPC), flat cables, circuit boards for tape automated bonding (TAB), etc. coated with screen printing ink or the like.

  Polyamideimide resins have been widely used as industrial materials in the fields of electricity, electronics, machinery, aviation and the like because of their excellent heat resistance, mechanical strength, electrical characteristics, chemical resistance, and the like. In particular, unlike a general polyimide resin, it is soluble in an organic solvent, so that it has been suitably used in applications where solution molding is essential, such as enamel varnish and coating material for electrical insulation. However, because of its inherently high moisture absorption rate, it has various disadvantages associated with it. For example, in order to use as an insulating material for a flexible printed wiring board, the insulation performance deteriorates under humidification, so that the application is such that a high voltage of 100V is applied (for example, a flexible printed wiring board used around a display). (FPC)) has a problem of poor reliability. In addition, when soldering is performed in a high humidity atmosphere, there is a problem that “blowing” or “peeling” occurs.

  In addition, the coefficient of thermal expansion and the expansion due to moisture absorption are high, and the thermal dimensional accuracy is not high enough to withstand higher density mounting due to the downsizing, multi-pin, fine pitch, etc. of the semiconductor package.

  Furthermore, since the dielectric loss tangent (tan δ) is higher than that of the polyimide film, it has been difficult to use it for FPC applications for electronic and electrical equipment at high frequencies.

  From these viewpoints, as a flexible metal-clad laminate for electronic / electrical equipment and a flexible printed board using the same, a laminate of a polyimide film and a copper foil has been mainly used. However, conventional flexible metal-clad laminates for flexible printed circuit boards are made by bonding polyimide film and metal foil with a thermosetting adhesive such as epoxy resin or acrylic resin. Since the thermal expansion coefficient of the base material (resin film layer) is high, the thermal dimensional stability is inferior, and the moisture resistance is inferior, so that the insulation and solder heat resistance are reduced after the humidification process. there were. Furthermore, because it is inferior in thermal dimensional stability, the flexible metal-clad laminate and the flexible printed circuit board obtained by processing the circuit in various heating processes are curled or inferior in moisture resistance. During the wet process, curling, twisting, and the like are generated on the substrate, and as a result, there is a problem that the yield is deteriorated in the circuit forming process and the mounting process on the flexible printed circuit board. In addition, the use of an adhesive between the polyimide film and the metal foil failed to exhibit the low dielectric loss tangent characteristic of polyimide, and the dielectric loss tangent of the adhesive determined the characteristics of electronic and electrical equipment. .

  In order to solve these problems, a technique for forming a metal foil directly on an insulating substrate without an adhesive has been studied (two-layer flexible metal-clad laminate). For example, Patent Document 1 forms a thin metal layer (seed layer) by a sputtering method on a polyimide film, Patent Document 2 by a vapor deposition method, and Patent Document 3 by an ion plating method. A technique for forming the film has been proposed. However, both methods have the disadvantage of high production costs, and there are problems such as pinholes when forming the seed layer and insufficient adhesion between the polyimide film and the conductor. .

  In order to provide a high-performance flexible printed circuit board without an adhesive layer at a lower cost, in Patent Documents 4 to 6 and the like, a polyamic acid-based solution that is a precursor of a polyimide resin is directly applied to a metal foil. A method for forming a flexible metal-clad laminate by dehydration reaction / polyimidization is proposed. However, the flexible metal-clad laminate obtained by such a method has a poor insulation performance after the humidification treatment due to a high moisture absorption rate of the resin and the like (for example, a high voltage is applied) The flexible printed circuit board used around the display) has a problem of poor reliability (migration resistance). In addition, solder heat resistance is also reduced after humidification, so application to lead-free solder (Ag—Sn—Bi, Ag—Sn—Cu, etc.) is restricted, or wet process and high humidity atmosphere There is a problem in that the yield in the circuit forming process and the mounting process deteriorates because the substrate is curled or twisted. In addition, it must be heat-treated at a high temperature after being molded (after coating) in the form of polyamic acid, which is a precursor, and therefore a two-layer flexible metal-clad laminate is continuously produced using the resin. However, there is a problem in that productivity is lowered, expensive equipment is required, and manufacturing costs are increased.

  As described above, the conventional technology is low in cost and excellent in dimensional stability and heat resistance, and does not deteriorate solder heat resistance or insulation even under humidification, and in any atmosphere (under humidification or In reality, there was no flexible metal-clad laminate for use in a two-layer flexible printed circuit board having a low dielectric loss tangent without heating or twisting.

Japanese Patent Laid-Open No. 02-98994 JP 62-181488 A JP-A-57-18357 JP-A-57-50670 JP-A-57-66690 JP-A-8-250860

  The object of the present invention is to solve the above problems, and is excellent in heat resistance, dimensional stability (low thermal expansion), low hygroscopicity, excellent insulating properties, and low dielectric loss tangent. It is an object of the present invention to provide a low-cost flexible metal-clad laminate for a flexible printed circuit board that can be used even in the periphery of a display where high reliability is required. That is, by directly applying and drying a heat-resistant resin solution on a metal foil, it is excellent in heat resistance, dimensional stability, adhesiveness, etc., and even when humidified, insulation, solder heat resistance is reduced, curl, dimensional change It is intended to manufacture a flexible metal-clad laminate for a flexible printed circuit board having no low dielectric loss tangent at low cost.

  As a result of diligent research to achieve the above object, the present inventors have developed a heat-resistant resin that simultaneously satisfies the properties of solvent solubility / low thermal expansibility / low hygroscopicity / low dielectric loss tangent, which are not present in the past. Is a successful one. That is, this invention is the following polyamideimide resin, a flexible metal-clad laminate using the same, and a flexible printed circuit board.

(1) When the total amount of the acid component is 100 mol%, the total amount of the amine (isocyanate) component is 100 mol%, and the total of the acid component and the amine (isocyanate) component is 200 mol%, the monomer having a biphenyl bond is Polyamideimide resin copolymerized by 90 mol% or more and 200 mol% or less.

(2) The polyamideimide resin according to (1), which has a logarithmic viscosity of 0.70 dl / g or more and 2.0 dl / g or less.

(3) Polyamideimide resin as described in (1) or (2) whose specific gravity is 1.3 or more.

(4) Polyamideimide resin in any one of (1)-(3) whose glass transition temperature is 250 degreeC or more.

(5) The polyamide-imide resin according to any one of (1) to (4), wherein the molar ratio of the imide bond to the amide bond is 75/25 to 55/45.

(6) The polyamide-imide resin according to any one of (1) to (5), which is non-halogen.

(7) The polyamidoimide resin in any one of (1)-(6) whose dielectric loss tangent is 0.010 or less.

(8) A flexible metal-clad laminate in which the polyamideimide resin according to any one of (1) to (7) is laminated on at least one surface of a metal foil.

(9) A flexible printed circuit board obtained by circuit processing using the flexible metal-clad laminate according to (8).

  The polyamide-imide resin of the present invention is excellent in heat resistance and thermal dimensional stability (low thermal expansion), has a low moisture absorption rate, does not deteriorate heat resistance and insulation properties even under humidification, and has a low dielectric loss tangent. Therefore, it is particularly useful as an insulating material for electrical and electronic applications, for example, a substrate for a flexible printed wiring board, a cover lay, and an adhesive.

  The low dielectric loss tangent of the polyamideimide resin of the present invention can be manifested by increasing the biphenyl bond concentration. Specifically, a monomer having a biphenyl bond when the total amount of the acid component is 100 mol%, the total amount of the amine (isocyanate) component is 100 mol%, and the total of the acid component and the amine (isocyanate) component is 200 mol%. Is copolymerized in an amount of 90 mol% to 200 mol%. Preferably it is 100 mol% or more, More preferably, it is 110 mol% or more. When the monomer having a biphenyl bond is less than 90 mol%, the dielectric loss tangent tends to increase. The upper limit is not limited, and 200 mol%, that is, all monomers may have a biphenyl bond.

  It is also important to increase the number of imide bonds for the low dielectric loss tangent of the polyamideimide resin. On the other hand, since the imide bond tends to deteriorate the solvent solubility, there exists an appropriate range of the amide bond concentration and the imide bond concentration. Specifically, those having a molar ratio of imide bond to amide bond of 75/25 to 55/45 are preferable. The molar ratio of the imide bond to the amide bond can determine the composition of the polyamide-imide resin by NMR analysis or the like, and from there, the molar ratio of the bond can be determined by calculation. When the imide bond increases from this range, the solvent solubility tends to decrease, and when the amide bond increases, the dielectric loss tangent may increase.

The dielectric loss tangent necessary for achieving the object of the present invention is 0.010 or less, preferably 0.008 or less. Although a minimum is not specifically limited, 0.0001 is preferable. The moisture absorption is 1.5% or less, preferably 1.0% or less, and the thermal expansion coefficient is 3.0 × 10 ⁻⁵ or less, preferably 2.5 × 10 ⁻⁵ . If the dielectric loss tangent is 0.01 or more, the S / N ratio deteriorates at high frequencies, and it becomes difficult to accurately transmit information. When the moisture absorption rate is 1.5% or more, the heat resistance and insulation under humidification decrease, and for example, it is difficult to suitably use as an insulating material for a printed wiring board. Similarly, when the thermal expansion coefficient is 2.5 × 10 ⁻⁵ or more, the thermal dimensional accuracy may be deteriorated. Therefore, insulating materials for printed wiring boards that require high-density mounting, coatings in the electrical and electronic fields, etc. It may be difficult to use as a material.

  In addition to the resin composition (monomer composition), the above-mentioned dielectric loss tangent and moisture absorption are affected by the carboxyl groups present at the ends of the polymer and at the side chains (which are not imidized and remain as amic acid). The smaller the amount, the better the moisture absorption rate, or the insulation, heat resistance, and dielectric loss tangent under humidification caused by it.

  The carboxyl group (acid value) can be quantified by the method described in Examples below, and is preferably 150 μeq / g or less, more preferably 120 μeq / g or less from the above viewpoint. .

  The lower limit of the acid value is not particularly specified from the viewpoint of dielectric loss tangent, moisture absorption, insulation, and heat resistance, but when it is 5 μeq / g or less, for example, when used as a coating material for electronic materials, etc. The adhesion to various adherends such as metals tends to decrease.

  The polyamideimide resin of the present invention preferably has a specific gravity of 1.3 or more. The upper limit is not particularly limited, but is preferably 1.5 or less from the viewpoint of solvent solubility. If the specific gravity is less than 1.3, the dielectric loss tangent may be lowered.

  The glass transition temperature of the polyamideimide resin of the present invention is preferably 250 ° C. or higher. More preferably, it is 280 degreeC or more. Although an upper limit is not specifically limited, 400 degreeC or less is preferable from a solvent solubility viewpoint. If the glass transition temperature is less than 250 ° C., solder heat resistance may be lowered.

  The production of the polyamideimide resin of the present invention can be synthesized by a usual method, for example, an isocyanate method, an acid chloride method, a low temperature solution polymerization method, a room temperature solution polymerization method and the like. From the viewpoint of reducing the number of groups (carboxyl groups), a particularly preferable production method is an isocyanate method in which a polymer is obtained by a decarboxylation reaction.

Examples of the acid component having a biphenyl bond used in the present invention include biphenyl-3,3 ′, 4,4′-tetracarboxylic acid, biphenyl-2,3,3 ′, 4′-tetracarboxylic acid, and one of these. An anhydride, a dianhydride, etc. can be used individually or in mixture of 2 or more types.
Examples of the amine component include 3,3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-diethyl-4,4′-diaminobiphenyl, 2,2′-dimethyl-4,4′-diamino. Biphenyl, 2,2′-diethyl-4,4′-diaminobiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3′-diethoxy-4,4′-diaminobiphenyl, 3,4 '-Diaminobiphenyl, 3,3'-diaminobiphenyl, or a diisocyanate corresponding to these may be used alone or in combination of two or more.

In addition to the above, it is also possible to copolymerize an acid component and an amine component shown below as long as the object of the present invention is not impaired.
Examples of the acid component include trimellitic acid, diphenyl ether-3,3 ′, 4′-tricarboxylic acid, diphenylsulfone-3,3 ′, 4′-tricarboxylic acid, benzophenone-3,3 ′, 4′-tricarboxylic acid, A tricarboxylic acid such as naphthalene-1,2,4-tricarboxylic acid and the monoanhydrides and esterified products thereof alone or as a mixture of two or more thereof, benzophenone-3,3 ′, 4,4′-tetracarboxylic Acid, diphenyl ether-3,3 ′, 4,4′-tetracarboxylic acid, alkylene glycol bis (trimellitate), bisphenol bis (trimellitate), pyromellitic acid, 3,3′-diphenylsulfonetetracarboxylic acid, naphthalene-2, 3,6,7-tetracarboxylic acid, naphthalene-1,2,4,5-tetracarboxylic acid, naphthalene- , 4,5,8- etc. and monoanhydride of these tetracarboxylic acids, dianhydrides, or ester can be used alone, or in combination of two or more.
Also, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid, p-oxybenzoic acid, p- (hydroxyethoxy) ) Aromatic oxycarboxylic acids such as benzoic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, dimer acid, cyclohexanedicarboxylic acid and other aliphatic dicarboxylic acids, fumaric acid, maleic acid, maleic anhydride, Examples thereof include unsaturated dicarboxylic acids such as itaconic acid, citraconic acid, 2,5-norbornane dicarboxylic anhydride, and tetrahydrophthalic anhydride.

  Examples of amine components include p-phenylenediamine, m-phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 3, 3'-diaminobenzanilide, 4,4'-diaminobenzanilide, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 2,6- Tolylenediamine, 2,4-tolylenediamine, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfide, 4,4′-diaminodiphenylpropane, 3,3′-diaminodiphenylpropane, 3, 3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane p-xylenediamine, m-xylenediamine, 1,4-naphthalenediamine, 1,5-naphthalenediamine, 2,6-naphthalenediamine, 2,7-naphthalenediamine, 2,2′-bis (4-aminophenyl) Propane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2-bis [4- ( 4-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] propane 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, There can be used singly or in combination of two or more of such diisocyanates corresponding to these.

  In the present invention, it is preferable that the polymer chain does not contain a halogen compound. In the monomer exemplified above, for example, 3,3′-dichloro-4,4′-diaminobiphenyl, 3,3 ′ -This means that a halogen element-containing monomer such as dibromo-4,4'-diaminobiphenyl is not used. Of course, even if a monomer containing a halogen element is used, the objects of the present invention such as solvent solubilization and low thermal expansion can be achieved. However, in this case, applications that can be used are limited due to environmental problems.

  The molecular weight of the polyamideimide resin used in the present invention is equivalent to 0.70 to 2.0 dl / g in N-methyl-2-pyrrolidone (polymer concentration 0.5 g / dl) as a logarithmic viscosity at 30 ° C. Those having a molecular weight are preferred, more preferably those having a molecular weight corresponding to 0.80 to 1.8 dl / g. When the logarithmic viscosity is less than 0.70 dl / g, mechanical properties may be insufficient when formed into a molded product such as a film, and when the viscosity is 2.0 dl / g or more, the solution viscosity becomes high. As a material, there is a possibility that molding processing may be difficult.

  The acid value and degree of polymerization can be controlled by polymerization conditions such as polymerization temperature and polymerization time, but in general, the molar balance between the acid component and the amine component, the use of a terminal blocker, or the acid component It can be controlled by the amount of anhydride group (control of monomer purity and moisture).

  As the end-capping agent, monocarboxylic acids such as phthalic anhydride and benzoic acid, monoanhydrides, monoamines such as aniline and phenyl isocyanate, monoisocyanates, and the like can be used. The molar balance of the acid component and the amine component is preferably such that the acid / amine ratio is in the range of 1.1 to 0.9 molar ratio, more preferably 1.00 to 1.05. A range of molar ratios. In addition, the purity of the anhydride in the acid component must be 95%, preferably 99% or more. In some cases, when the polycarboxylic acid is copolymerized, the acid component described above should be used. Can do.

As a solvent for producing the polyamideimide resin solution of the present invention, an organic solvent capable of dissolving the polyamideimide resin can be used. Typical examples of such organic solvents include, for example, N-methyl-2-pyrrolidone, N, N′-dimethylformamide, N, N′-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea , Sulfolane, dimethyl sulfoxide, γ-butyrolactone, cyclohexanone, cyclopentanone, etc., preferably N-methyl-2-pyrrolidone. When these solvents are used as the polymerization solvent, the polymerization solvent can be used as it is as the solvent.
In addition, some of these organic hydrocarbon solvents such as toluene and xylene, ether organic solvents such as diglyme, triglyme and tetrahydrofuran, ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone, alcohols such as methanol, ethanol and isopropanol It is also possible to add a kind or to replace a part or the whole.

  The concentration of the resin solution is desirably 0.5% by weight or more, preferably 2% by weight or more, more preferably 5% by weight or more, further preferably 7% by weight or more, and particularly preferably 10% by weight or more. . If the concentration is less than 0.5% by weight, the concentration tends to be too low, and problems such as a lack of thickness in coating and the like are likely to occur. The upper limit of the concentration of the resin solution is not particularly limited, but if it is too high, the solution viscosity becomes too high and handling is hindered, and therefore it is preferably 70% by weight or less.

  In each application, if necessary, for example, for the purpose of improving mechanical properties, electrical properties, slipperiness, flame retardancy, etc., the above heat-resistant resin solution of the present invention may contain other resins and organic compounds, And an inorganic compound may be mixed or reacted to be used in combination. For example, lubricants (silica, talc, etc.), adhesion promoters, flame retardants (phosphorus, triazine, aluminum hydroxide, etc.), stabilizers (antioxidants, UV absorbers, polymerization inhibitors, etc.), plating activators , Organic and inorganic fillers (talc, titanium oxide, fluoropolymer fine particles, pigments, dyes, calcium carbide, etc.), other silicone compounds, fluorine compounds, isocyanate compounds, blocked isocyanate compounds, acrylic resins, urethane resins, polyester resins A resin or organic compound such as a polyamide resin, an epoxy resin, a phenol resin, or a polycarbonate resin, or an inorganic compound such as a curing agent, silicon oxide, titanium oxide, calcium carbonate, iron oxide, or the like that does not impair the object of the present invention. Can be used together.

  The polyamideimide resin and the solution thereof of the present invention can be suitably used as industrial materials for fibers, films, etc., electricity, electronics, aviation, machinery, space, etc., but particularly preferred embodiments are insulating materials in the electrical and electronic fields, In particular, it can be used as a substrate for a flexible printed wiring board, a coverlay, an adhesive, and the like. A conventionally known method can be applied as the molding method, for example, solution casting.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not particularly limited by the examples. The evaluation method of the characteristic value in each example is as follows. In addition, the powdery sample used for evaluation was prepared by reprecipitation and purification of the polymerization dope obtained in each Example with a large amount of acetone. Moreover, the resin film was produced by the following operations.

<Production of resin film>
1) Thickness after solvent removal of the resin solutions obtained in each of Examples and Comparative Examples using a knife coater on a rolled copper foil (trade name “BHY-22BT”, manufactured by Japan Energy Co., Ltd.) having a thickness of 18 μm. Was coated to be 20 μm. Then, it was dried at a temperature of 120 ° C. for 3 minutes.
2) The above laminate was wound around an aluminum tube having an outer diameter of 12 inches so that the coated surface was on the outside, and was heat-treated with a vacuum dryer and an inert oven under the following conditions.
Drying conditions under reduced pressure; 200 ° C x 24 hours
(The degree of vacuum was varied between 10 and 100 Pa by volatilization of the solvent)
Heating under nitrogen (flow rate: 20 L / min); 280 ° C. × 3 hr
3) Next, the copper foil of the obtained laminate was etched with 35% ferric chloride to obtain a resin film.

<Logarithmic viscosity>
The powdered sample obtained by reprecipitation / purification is dissolved in N-methyl-2-pyrrolidone so that the polymer concentration is 0.5 g / dl, and the solution viscosity of the solution and the solvent viscosity are 30 ° C. , Measured with an Ubbelohde viscosity tube and calculated according to the following formula.
Logarithmic viscosity (dl / g) = [ln (V ₁ / V ₂ )] / V ₃
In the above formula, V ₁ represents a solution viscosity measured with an Ubbelohde type viscosity tube, V ₂ represents a solvent viscosity measured with an Ubbelohde type viscosity tube, and V ₁ and V ₂ represent a polymer solution and a solvent (N-methyl- 2-pyrrolidone) was determined from the time it took to pass through the capillary of the viscosity tube. V ₃ is the polymer concentration (g / dl).

<Glass transition temperature>
The glass transition temperature of the resin film was measured under the following conditions by TMA (thermal mechanical analysis / manufactured by Rigaku Corporation) tensile load method. The resin film was measured for a film that was once heated to an inflection point in nitrogen at a heating rate of 10 ° C./min and then cooled to room temperature.
Load: 1g
Sample size: 4 (width) x 20 (length) mm
Temperature increase rate: 10 ° C / min
Atmosphere: Nitrogen

<Acid value>
Using a powdered sample obtained by reprecipitation and purification, measurement was performed under the following conditions using an automatic potentiometric titrator (AT310) manufactured by Kyoto Electronics Co., Ltd.
Titration solution: 1/100 N potassium hydroxide (ethanol / dimethylformamide solution)
Titration solution: Concentration 0.1 g / dl, solvent N-methyl-2-pyrrolidone / dimethylformamide mixed solvent

<Solubility>
The solution adjusted to a concentration of 10% by weight was allowed to stand at 25 ° C. for 24 hours, and it was determined that the solution without any gelation, non-uniformity, white turbidity, or precipitation was dissolved (○ soluble, X No solubility).

<Hygroscopic rate>
A resin film having a length and a width of 50 ± 1 mm was measured by the following method. (When the cut surface of the sample was rough, it was finished smoothly with a polishing paper of P240 or higher as defined in JIS R 6252).
(1) The sample is allowed to stand for 24 hours in a thermostat kept at 50 ± 2 ° C.
(2) The humidity is adjusted for 24 hours at 40 ° C. and 90% RH so that the samples do not contact each other.
(3) After humidity control, the sample is put in a weighing bottle within 20 seconds and sealed (or the treatment of (2) is carried out with the weighing bottle (with the lid open)), and 20 ± 10 in a desiccator. After cooling to ° C., weigh the sample after moisture absorption to the nearest 1 mg. (The dust on the surface of the sample is removed with feathers or a brush.) (W ₁ )
(4) The sample is dried for 1 hour in a thermostat kept at 100 ± 5 ° C.
(5) The treated sample is cooled to 20 ± 10 ° C. in a desiccator, and its mass is accurately measured to the unit of 1 mg. (W ₀ )
(6) Calculate the moisture absorption rate WA (%) by the following formula: WA = (W ₁ −W ₀ ) / W ₀ × 100 (%)
W ₁ : Weight of sample after moisture absorption (g)
W ₀ : Weight of sample before moisture absorption (g)

ε_c：比誘電率
Ｃ ：静電容量
ｄ ：フィルム厚み
Ｓ ：測定面積
ε₀：真空の誘電率
b)誘電正接
安藤電気株式会社製 ＳＥ−３０型電極（電極直径３７ｍｍ）にフィルムをセットし、同じく安藤電気株式会社製ＴＲ−１０型誘電体損測定器（インピーダンスブリッジ）を用い、誘電正接を測定した。（周波数 １００kHz） <Relative permittivity, dielectric loss tangent>
a) Dielectric constant The obtained film is sandwiched between circular metal electrodes with a diameter of 18 mm to constitute a capacitor, and the capacitance C of the capacitor obtained by the Yokogawa Hewlett-Packard impedance meter YHP4192A LF impedance analyzer And calculated from the following equation. (Frequency 100kHz)

ε _c : relative dielectric constant C: capacitance d: film thickness S: measurement area ε ₀ : vacuum dielectric constant
b) Dielectric loss tangent Set the film on the SE-30 type electrode (electrode diameter 37 mm) manufactured by Ando Electric Co., Ltd., and also use the TR-10 type dielectric loss measuring instrument (impedance bridge) manufactured by Ando Electric Co., Ltd. It was measured. (Frequency 100kHz)

Example 1
Trimellitic anhydride (hereinafter abbreviated as TMA; 150 ° C., 1 Torr sublimation purification; purity 99.9 mol%, trimellitic acid content 0.1 mol%) 153.7 g (80 mol%), 4, 48.3 g (15 mol%) of 4′-benzophenonetetracarboxylic dianhydride (hereinafter BTDA; purity 99%), 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA; purity 99%) 14.7 g (5 mol%), 3,3′-dimethyl-4,4′-biphenyl diisocyanate (hereinafter TODI; purity 99%) 264.3 g (100 mol%), diazabicyclo [5.4.0] undecene -7 (hereinafter referred to as DBU) and 2230 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP; purity 99.9% or more) were added, the temperature was raised to 100 ° C. under a nitrogen stream, and 2 at 100 ° C. It was between reaction. Subsequently, after making it react at 150 degreeC for 1 hour, 1307g (polymer concentration 10 weight%) of NMP was added and it cooled to room temperature.
Using the obtained polymer solution, a flexible metal-clad laminate was produced under the following molding process conditions, and various properties having the contents shown in Tables 1 to 3 were evaluated.
(A) Initial drying step Using the knife coater on the 18 μm thick electrolytic copper foil (trade name “USLP-R2”, manufactured by Nihon Denki Co., Ltd.), the resin solution obtained above has a thickness after desolvation. Coating was performed to 25 μm. Subsequently, it dried for 3 minutes at the temperature of 120 degreeC, and the flexible metal-clad laminate which was initially dried was obtained.
(B) Heat treatment / solvent removal step The above-mentioned initially dried laminate is wound on an aluminum can with an outer diameter of 16 inches so that the coated surface is on the outside, and the heat treatment / removal step shown below is performed with a vacuum dryer or an inert oven. It heat-processed on solvent removal conditions. (The solvent in the coating was completely removed.)
Drying conditions under reduced pressure: 200 ° C. × 24 hr (the degree of reduced pressure varied between 10 and 100 Pa due to volatilization of the solvent)
Heating under nitrogen (flow rate; 20 L / min); 280 ° C. × 3 hr
The flexible metal-clad laminate was evaluated by the following method.

<Solder heat resistance (normal)>
A metal foil of a flexible metal-clad laminate was etched by a subtractive method, and a sample with a circuit pattern with a width of 1 mm (35% ferric chloride solution) was conditioned at 25 ° C and 65% (humidity) for 24 hours. After flux cleaning, it was immersed in a jet solder bath at 320 ° C. for 20 seconds, and the presence or absence of peeling or swelling was observed with a microscope. ○ indicates that there is no peeling or swelling, and × indicates that peeling or swelling has occurred.

<Solder heat resistance (after humidification treatment)>
A metal foil of a flexible metal-clad laminate was etched by a subtractive method, and a sample of a circuit pattern with a width of 1 mm (35% ferric chloride solution) was conditioned at 40 ° C and 90% (humidity) for 24 hours. After flux cleaning, it was immersed in a jet solder bath at 320 ° C. for 20 seconds, and the presence or absence of peeling or swelling was observed with a microscope. ○ indicates that there is no peeling or swelling, and × indicates that peeling or swelling has occurred.

<Dimensional change rate>
Measurement was performed in the MD direction and the TD direction under the conditions of 150 ° C. × 30 minutes with IPC-FC241 (IPC-TM-650, 2.2.4 (c)).

<Adhesive strength>
According to IPC-FC241 (IPC-TM-650, 2.4.9 (A)), the adhesive strength between the circuit pattern and the heat-resistant resin layer was measured using a sample in which the circuit pattern was created by the subtractive method.

Example 2
In a reaction vessel, 153.7 g (80 mol%) of TMA, 32.2 g (10 mol%) of BTDA, 14.7 g (5 mol%) of BPDA, 3,3 ′, 4,4′-diphenyl ether tetracarboxylic dianhydride (hereinafter referred to as ODPA). Purity 99%), 15.5 g (5 mol%), TODI 264.3 g (100 mol%), DBU 1.5 g, and NMP 2220 g (polymer concentration; 15 wt%) were added, and the temperature was raised to 100 ° C. under a nitrogen stream. And reacted at 100 ° C. for 2 hours. Subsequently, it was made to react at 160 degreeC for 3 hours, and it cooled to room temperature.
Using the obtained polymer solution, a flexible metal-clad laminate was produced in the same manner as in Example 1, and various characteristics shown in Tables 1 to 3 were evaluated.

Example 3
To the reaction vessel, 134.5 g (70 mol%) of TMA, 80.6 g (25 mol%) of BTDA, 14.7 g (5 mol%) of BPDA, 264.3 g (100 mol%) of TODI, 1.5 g of DBU and 2300 g of NMP were added. The temperature was raised to 100 ° C., and the mixture was reacted at 100 ° C. for 2 hours. Subsequently, after making it react at 150 degreeC for 2 hours and 150 degreeC for 2 hours, it cooled to room temperature.
Using the obtained polymer solution, a flexible metal-clad laminate was produced in the same manner as in Example 1, and various characteristics shown in Tables 1 to 3 were evaluated.

Example 4
In a reaction vessel, 153.7 g (80 mol%) of TMA, 32.2 g (10 mol%) of BTDA, 29.4 g (10 mol%) of BPDA, 264.3 g (100 mol%) of TODI, 1.5 g of DBU, and 2220 g of NMP (polymer concentration; 15 % By weight), the temperature was raised to 100 ° C. under a nitrogen stream, and the reaction was carried out at 100 ° C. for 2 hours. Subsequently, it was made to react at 160 degreeC for 3 hours, and it cooled to room temperature.
Using the obtained polymer solution, a flexible metal-clad laminate was produced in the same manner as in Example 1, and various characteristics shown in Tables 1 to 3 were evaluated.

Example 5
To the reaction vessel, 153.7 g (80 mol%) of TMA, 58.8 g (20 mol%) of BPDA, 264.3 g (100 mol%) of TODI, 1.5 g of DBU, and 2203 g of NMP (polymer concentration; 15 wt%) were added under a nitrogen stream. The temperature was raised to 100 ° C., and the mixture was reacted at 100 ° C. for 2 hours. Subsequently, it was made to react at 160 degreeC for 3 hours, and it cooled to room temperature.
Using the obtained polymer solution, a flexible metal-clad laminate was produced in the same manner as in Example 1, and various characteristics shown in Tables 1 to 3 were evaluated.

Comparative Example 1
In a reaction vessel, 153.7 g (80 mol%) of TMA, 42.0 g (20 mol%) of trimellitic acid, 211.4 g (80 mol%) of TODI (purity 99% or more), 4,4′-diphenylmethane diisocyanate 50. 1 g (20 mol%), 1.5 g of potassium fluoride, and 1477 g of NMP were added, the temperature was raised to 50 ° C. under a nitrogen stream, and the mixture was reacted at 50 ° C. for 2 hours. Next, after reacting at 100 ° C. for 10 hours and at 120 ° C. for 5 hours, 615 g of NMP (polymer concentration 15% by weight) was further added, and the mixture was cooled to room temperature.
Using the obtained polymer solution, a flexible metal-clad laminate was produced in the same manner as in Example 1, and various characteristics shown in Tables 1 to 3 were evaluated.

Comparative Example 2
BTDA 322.2 g (100 mol%), TODI 264.3 g (100 mol%), and NMP 1979 g were added to the reaction vessel, heated to 100 ° C. under a nitrogen stream, and reacted at 100 ° C. for 2 hours. It did not dissolve in the solvent and became a heterogeneous solution.

Comparative Example 3
294.2 g (100 mol%) of BPDA, 264.3 g (100 mol%) of TODI, and 1882 g of NMP were added to the reaction vessel, and the temperature was raised to 100 ° C. under a nitrogen stream and reacted at 100 ° C. for 2 hours. It did not dissolve in the solvent and became a heterogeneous solution.

Comparative Example 4
In a reaction vessel, TMA 192.3 g (100 mol%), TODI 185.0 g (70 mol%), 2,4-diisocyanatotoluene 52.2 g (30 mol%), DBU 1.5 g, and NMP 1934 g (polymer concentration; 15 weight) %) Was added, the temperature was raised to 100 ° C. under a nitrogen stream, and the mixture was reacted at 100 ° C. for 2 hours. Subsequently, it was made to react at 160 degreeC for 3 hours, and it cooled to room temperature.
Using the obtained polymer solution, a flexible metal-clad laminate was produced in the same manner as in Example 1, and various characteristics shown in Tables 1 to 3 were evaluated.

Comparative Example 5
To the reaction vessel, 192.3 g (100 mol%) of TMA, 250.3 g (100 mol%) of 4,4′-diphenylmethane diisocyanate, 1.5 g of DBU, and 2009 g of NMP (polymer concentration; 15 wt%) were added. The temperature was raised to 0 ° C. and reacted at 100 ° C. for 2 hours. Subsequently, it was made to react at 160 degreeC for 3 hours, and it cooled to room temperature.
Using the obtained polymer solution, a flexible metal-clad laminate was produced in the same manner as in Example 1, and various characteristics shown in Tables 1 to 3 were evaluated.

Comparative Example 6
In a reaction vessel, 153.7 g (80 mol%) of TMA, 34.4 g (20 mol%) of 1,4-cyclohexanedicarboxylic acid, 222.3 g (100 mol%) of isophorone diisocyanate, 1.5 g of DBU, and 1827 g of NMP (polymer concentration; 15 % By weight), the temperature was raised to 100 ° C. under a nitrogen stream, and the reaction was carried out at 100 ° C. for 2 hours. Subsequently, it was made to react at 160 degreeC for 3 hours, and it cooled to room temperature.
Using the obtained polymer solution, a flexible metal-clad laminate was produced in the same manner as in Example 1, and various characteristics shown in Tables 1 to 3 were evaluated.

  As described above, the polyamide-imide resin of the present invention is excellent in heat resistance, dimensional stability (low thermal expansion), has a low moisture absorption rate, and has a low dielectric loss tangent. For example, it is useful as a substrate for a flexible printed wiring board, a coverlay, an adhesive, and the like.

Claims (9)

  When the total amount of the acid component is 100 mol%, the total amount of the amine (isocyanate) component is 100 mol%, and the total of the acid component and the amine (isocyanate) component is 200 mol%, the monomer having a biphenyl bond is 90 mol%. Polyamideimide resin copolymerized in an amount of 200 mol% or less.   The polyamide-imide resin according to claim 1, having a logarithmic viscosity of 0.70 dl / g or more and 2.0 dl / g or less.   The polyamideimide resin according to claim 1 or 2, wherein the specific gravity is 1.3 or more.   The polyamideimide resin according to any one of claims 1 to 3, which has a glass transition temperature of 250 ° C or higher.   The polyamide-imide resin according to any one of claims 1 to 4, wherein a molar ratio of the imide bond to the amide bond is 75/25 to 55/45.   The polyamide-imide resin according to claim 1, which is non-halogen.   Dielectric loss tangent is 0.010 or less, The polyamide-imide resin in any one of Claims 1-6.   A flexible metal-clad laminate in which the polyamideimide resin according to any one of claims 1 to 7 is laminated on at least one surface of a metal foil.   A flexible printed circuit board obtained by circuit processing using the flexible metal-clad laminate according to claim 8.