JP2022058252A - Resin composition, resin film, laminate, cover lay film, copper foil with resin, metal-clad laminate and circuit board - Google Patents

Abstract

To provide a resin composition using polyimide which enables formation of an insulating resin layer excellent in peel strength to a metal layer and soldering heat resistance without impairing dielectric characteristics.SOLUTION: A resin composition contains (A) polyimide obtained by reaction of a tetracarboxylic acid anhydride component with a diamine component, and (B) a magnesium oxide filler having an average particle diameter of 30 nm to 10 μm, in which a content of the component (B) to the total content of the component (A) and the component (B) is within a range of 1-50 wt.%. The filler-containing thermoplastic resin layer obtained by forming the resin composition into a film preferably has a dielectric loss tangent (Tanδ) at 10 GHz measured by a split post dielectric resonator (SPDR) after 24-h humidity conditioning under constant temperature/humidity conditions of 23°C and 50% RH of 0.0022 or less.SELECTED DRAWING: None

Description

The present invention relates to a resin composition, a resin film, a laminate, a coverlay film, a copper foil with a resin, a metal-clad laminate, and a circuit board useful as an adhesive in a circuit board such as a printed wiring board.

In recent years, with the progress of miniaturization, weight reduction, and space saving of electronic devices, a flexible printed wiring board (FPC) that is thin and lightweight, has flexibility, and has excellent durability even after repeated bending. The demand for Circuits) is increasing. Since FPC can be mounted three-dimensionally and at high density even in a limited space, it can be used for wiring of moving parts of electronic devices such as HDDs, DVDs, and mobile phones, and for parts such as cables and connectors. It is expanding.

In addition to the above-mentioned high density, the high performance of the equipment has advanced, so it is also necessary to cope with the high frequency of the transmission signal. In information processing and information communication, efforts are being made to increase the transmission frequency in order to transmit and process large volumes of information, and the printed circuit board material has a transmission loss due to the thinning of the insulating layer and the improvement of the dielectric properties of the insulating layer. Is required to decrease. In the future, FPCs and adhesives that can handle higher frequencies will be required, and it will be important to reduce transmission loss. As for the improvement of the dielectric property of the printed substrate material, a resin composition in which an ethylene-propylene-diene copolymer is mixed with spherical silica surface-treated with a surface-treating agent having a polymerizable unsaturated bond has been proposed ( For example, Patent Document 1).

By the way, polyimide is widely used as a printed circuit board material for forming an insulating resin layer including an adhesive layer, and scaly talc may be added to a polyimide resin composition applied as an adhesive for a coverlay film. It has been proposed (eg, Patent Document 2).
Further, although it is not related to the printed substrate material, it contains the first particle having an average particle diameter in the range of 50 μm or more and 150 μm or less and the second particle having an average particle diameter in the range of 1 μm or more and less than 50 μm, and the first particle. And it has been proposed to add a flame retardant whose second particle material is magnesium oxide to the thermoplastic resin composition (for example, Patent Document 3). However, in Patent Document 3, magnesium oxide particles are added for the purpose of improving the flame retardancy of the resin molded product, and are not expected to be applied as a printed circuit board material such as FPC capable of high frequency signal transmission. .. Moreover, in the specific examples, the application to the acrylic resin is only considered.

International release WO2016 / 026927 Japanese Patent No. 5777944 Japanese Unexamined Patent Publication No. 2019-127558 Japanese Unexamined Patent Publication No. 2017-137375

In general, the addition of the filler to the insulating resin layer acts in a direction of weakening the adhesiveness with the metal layer and other insulating resin layers. In a circuit board such as an FPC, if the adhesion between the insulating resin layer and the wiring layer is low, the wiring may be displaced or peeled off, resulting in a decrease in the reliability of the circuit board. Therefore, in a circuit board, it is very important to maintain the adhesion between the insulating resin layer and the wiring layer, and it is required to secure the peel strength and the solder heat resistance with the metal layer.

Therefore, an object of the present invention is to provide a resin composition using polyimide, which can form an insulating resin layer having excellent peel strength and solder heat resistance with a metal layer without impairing the dielectric properties.

The resin composition of the present invention comprises the following components (A) and (B);
(A) Polyimide obtained by reacting a tetracarboxylic acid anhydride component with a diamine component, and (B) a magnesium oxide filler having an average particle size in the range of 30 nm to 10 μm.
The content of the component (B) is in the range of 1 to 50% by weight with respect to the total amount of the component (A) and the component (B).

In the resin composition of the present invention, the magnesium oxide filler may contain 95.0% by weight or more of magnesium oxide.

In the resin composition of the present invention, the magnesium oxide filler has a weight loss rate of 2% or less at 350 ° C. when heated from 30 ° C. to 450 ° C. at a heating rate of 10 ° C. per minute in thermogravimetric analysis measurement. There may be.

In the resin composition of the present invention, the magnesium oxide filler may be one in which a peak derived from magnesium hydroxide is not detected by X-ray diffraction measurement.

In the resin composition of the present invention, the diamine component contains 40 mol% or more of an aliphatic diamine with respect to the total diamine component.
The average particle size of the magnesium oxide filler may be in the range of 200 nm to 10 μm.

The resin composition of the present invention is a dimer diamine composition containing dimer diamine as a main component, wherein the aliphatic diamine is a dimer diamine in which two terminal carboxylic acid groups of dimer acid are replaced with a primary aminomethyl group or an amino group. There may be.

The resin composition of the present invention may further contain an amino compound having at least two primary amino groups as functional groups.

The resin film of the present invention is a resin film containing a filler-containing thermoplastic resin layer.
The filler-containing thermoplastic resin layer is formed from the resin composition.

In the resin film of the present invention, the filler-containing thermoplastic resin layer is measured by a split post dielectric resonator (SPDR) at 10 GHz after humidity control for 24 hours under constant temperature and humidity conditions of 23 ° C. and 50% RH. The dielectric loss tangent (Tan δ) in the above may be 0.0022 or less.

The laminate of the present invention is a laminate having a substrate and an adhesive layer laminated on at least one surface of the substrate, and the adhesive layer is characterized by being made of the resin film. And.

The coverlay film of the present invention is a coverlay film having a coverlay film material layer and an adhesive layer laminated on the coverlay film material layer, and the adhesive layer is made from the above resin film. It is characterized by becoming.

The copper foil with resin of the present invention is a copper foil with resin in which an adhesive layer and a copper foil are laminated, and the adhesive layer is made of the resin film.

The metal-clad laminate of the present invention is a metal-clad laminate having an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer, and at least one layer of the insulating resin layer is It is characterized by being made of the above resin film.

The circuit board of the present invention is formed by wiring processing the metal layer of the metal-clad laminate.

Since the resin composition of the present invention contains polyimide and a magnesium oxide filler having an average particle diameter in the range of 30 nm to 10 μm, it has sufficient solder heat resistance and peel strength for practical use while maintaining a low dielectric loss tangent. It is possible to form a resin film having excellent adhesiveness. Therefore, the resin composition and the resin film of the present invention can be particularly preferably used as a circuit board material for FPCs and the like in electronic devices that require high-speed signal transmission, for example.

It is a chart which shows the result of the thermogravimetric analysis measurement of Test Example 1. It is a chart which shows the result of the X-ray diffraction measurement of Test Example 2.

Hereinafter, embodiments of the present invention will be described.

[Resin composition]
The resin composition according to the embodiment of the present invention comprises the following components (A) and (B);
(A) Polyimide obtained by reacting a tetracarboxylic acid anhydride component with a diamine component, and (B) a magnesium oxide filler having an average particle size in the range of 30 nm to 10 μm.
Contains.

<(A) component: polyimide>
The polyimide of the component (A) contains a tetracarboxylic acid residue and a diamine residue. In the present invention, the tetracarboxylic acid residue represents a tetravalent group derived from tetracarboxylic acid dianhydride, and the diamine residue is a divalent group derived from a diamine compound. Represents that. When the tetracarboxylic acid anhydride and the diamine compound, which are the raw materials, are reacted in approximately equimolar amounts, the types of the tetracarboxylic acid residues and the diamine residues contained in the polyimide are determined with respect to the type and molar ratio of the raw materials. The molar ratio can be almost made to correspond.

The term "polyimide" in the present invention means a resin composed of a polymer having an imide group in its molecular structure, such as polyamideimide, polyetherimide, polyesterimide, polysiloxaneimide, and polybenzimidazoleimide, in addition to polyimide. ..

The polyimide of the component (A) may be a thermoplastic polyimide or a non-thermoplastic polyimide, but a thermoplastic polyimide is preferable, and a tetracarboxylic acid anhydride component and a diamine component containing 40 mol% or more of an aliphatic diamine are used. A solvent-soluble thermoplastic polyimide obtained by imidizing the polyamic acid of the precursor obtained by the reaction is more preferable. The "thermoplastic polyimide" is a polyimide that is generally softened by heating, solidified by cooling, and can be repeated, and the glass transition temperature (Tg) can be clearly confirmed. It means a polyimide in which the glass transition temperature can be clearly confirmed in a temperature range of less than 150 ° C. Further, from the viewpoint of thermal pressure bonding at low temperature, polyimide is preferable because the glass transition temperature can be clearly confirmed in a temperature range of less than 100 ° C., and storage at 30 ° C. measured using a dynamic viscoelastic modulus measuring device (DMA) is preferable. A polyimide having an elastic modulus of 1.0 × 10 ⁸ Pa or more and a storage elastic modulus of less than 3.0 × 10 ⁷ Pa at a glass transition temperature of + 30 ° C. is more preferable. The "non-thermoplastic polyimide" is a polyimide that generally does not soften or show adhesiveness even when heated, but in the present invention, it was measured using a dynamic viscoelasticity measuring device (DMA). A polyimide having a storage elastic modulus of 1.0 × 10 ⁹ Pa or more at ° C. and a storage elastic modulus of 3.0 × 10 ⁸ Pa or more at 300 ° C.

(Tetracarboxylic dianhydride component)
The polyimide of the component (A) can contain a tetracarboxylic acid residue derived from a tetracarboxylic acid anhydride generally used for polyimide without particular limitation, but the following for all tetracarboxylic acid residues is described below. It is preferable that the tetracarboxylic acid residue derived from the tetracarboxylic acid anhydride represented by the general formula (1) is contained in an amount of 90 mol% or more in total. By containing 90 mol% or more of the tetracarboxylic acid residue derived from the tetracarboxylic acid anhydride represented by the following general formula (1) in total with respect to all the tetracarboxylic acid residues, the polyimide is flexible. It is preferable that both property and heat resistance are easy to achieve. If the total amount of tetracarboxylic acid residues derived from the tetracarboxylic dianhydride represented by the following general formula (1) is less than 90 mol%, the solvent solubility of the polyimide tends to decrease.

In the general formula (1), X represents a single bond or a divalent group selected from the following formula.

In the above equation, Z indicates -C ₆ H ₄ -,-(CH ₂ ) n- or -CH ₂ -CH (-OC (= O) -CH ₃ ) -CH _2- , where n is 1. Indicates an integer of ~ 20.

Examples of the tetracarboxylic acid anhydride represented by the general formula (1) include 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride (BPDA), 3,3', 4,4'. -Benzophenone tetracarboxylic acid dianhydride (BTDA), 3,3', 4,4'-diphenylsulfone tetracarboxylic acid dianhydride (DSDA), 4,4'-oxydiphthalic acid anhydride (ODPA), 4,4 '-(Hexafluoroisopropylidene) diphthalic anhydride (6FDA), 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride (BPADA), p-phenylenebis (trimerit) Acid monoester acid anhydride) (TAHQ), ethylene glycol bisanhydrotrimeritate (TMEG) and the like can be mentioned. Among these, especially when 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA) is used, the adhesiveness of the polyimide can be improved, and the ketone group present in the molecular skeleton can be used. In some cases, the amino group of the amino compound for forming a crosslink, which will be described later, reacts to form a C = N bond, and the effect of improving heat resistance is likely to be exhibited. From this point of view, the tetravalent tetracarboxylic acid residue (BTDA residue) derived from BTDA is preferably 50 mol% or more, more preferably 60 mol% or more, based on all the tetracarboxylic acid residues. May contain.

The polyimide of the component (A) contains a tetracarboxylic acid residue derived from an acid anhydride other than the tetracarboxylic acid anhydride represented by the above general formula (1) as long as the effect of the invention is not impaired. Can be done. The tetracarboxylic acid residue is not particularly limited, but for example, pyromellitic acid dianhydride, 2,3', 3,4'-biphenyltetracarboxylic acid dianhydride, 2,2', 3 , 3'-or 2,3,3', 4'-benzophenone tetracarboxylic acid dianhydride, 2,3', 3,4'-diphenyl ether tetracarboxylic acid dianhydride, bis (2,3-dicarboxyphenyl) ) Ether dianhydride, 3,3'', 4,4''-, 2,3,3'', 4''-or 2,2'',3,3''-p-terphenyltetracarboxylic Acid dianhydride, 2,2-bis (2,3- or 3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3- or 3,4-dicarboxyphenyl) methane dianhydride, Bis (2,3- or 3,4-dicarboxyphenyl) sulfonate dianhydride, 1,1-bis (2,3- or 3,4-dicarboxyphenyl) ethane dianhydride, 1,2,7, 8-1,2,6,7-or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride, 2,2-bis (3,4-Dicarboxyphenyl) Tetrafluoropropane dianhydride 2,3,5,6-cyclohexane dianhydride 1,2,5,6-naphthalene tetracarboxylic acid dianhydride 1,4,5 , 8-naphthalenetetracarboxylic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1 , 2,5,6-Tetracarboxylic acid dianhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-Tetracarboxylic acid dianhydride, 2,3,6,7-( Or 1,4,5,8-) Tetrachloronaphthalene-1,4,5,8-(or 2,3,6,7-) Tetracarboxylic acid dianhydride 2,3,8,9-3 , 4,9,10-, 4,5,10,11-or 5,6,11,12-perylene-tetracarboxylic acid dianhydride, cyclopentane-1,2,3,4-tetracarboxylic acid dianhydride, Pyrazine-2,3,5,6-tetracarboxylic acid dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic acid dianhydride, thiophene-2,3,4,5-tetracarboxylic acid dianhydride Examples thereof include tetracarboxylic acid residues derived from aromatic tetracarboxylic acid dianhydrides such as anhydrous, 4,4'-bis (2,3-dicarboxyphenoxy) diphenylmethane dianhydride.

(Diamine component)
As the polyimide of the component (A), the diamine component generally used for polyimide can be used as the diamine component of the raw material without particular limitation, but preferably, 40 mol% or more of the aliphatic diamine is used with respect to the total diamine component. More preferably, it is preferable to use a diamine component containing 60 mol% or more. That is, the polyimide of the component (A) preferably contains 40 mol% or more, more preferably 60 mol% or more, of the diamine residue derived from the aliphatic diamine with respect to all the diamine residues. .. By containing the diamine residue derived from the aliphatic diamine in the above amount, the dielectric property of the polyimide is improved, and the thermocompression bonding property is improved and lowered by lowering the glass transition temperature of the polyimide (lower Tg). Internal stress can be relaxed by increasing the elastic modulus. If the amount of diamine residue derived from the aliphatic diamine is less than 40 mol% with respect to all the diamine residues, the effect of improving the dielectric loss tangent and the thermocompression bonding characteristics cannot be sufficiently obtained. Here, as the aliphatic diamine, for example, a dimerdiamine composition containing dimerdiamine as a main component, in which two terminal carboxylic acid groups of dimeric acid are substituted with a primary aminomethyl group or an amino group, hexamethylenediamine. , Dodecanediamine, cyclohexanediamine, polyoxyalkyleneamine, 4,4-diaminodicyclohexylmethane and the like can be used, and a dimer diamine composition is particularly preferable.

(Diamine Diamine Composition)
The diamine diamine composition contains the following component (a) as a main component, and the amounts of the components (b) and (c) are controlled.

(A) Dimer diamine;
In the diamine diamine of the component (a), the two terminal carboxylic acid groups (-COOH) of the dimer acid are replaced with a primary aminomethyl group ( _-CH2 -NH ₂ ) or an amino group (-NH ₂ ). Means diamine. Dimer acid is a known dibasic acid obtained by an intermolecular polymerization reaction of unsaturated fatty acids, for example, natural fatty acids such as soybean oil fatty acid, tall oil fatty acid, rapeseed oil fatty acid, and purified oleic acid and linolenic acid. It is a dimerized fatty acid obtained by subjecting a deal-alder reaction using linolenic acid, erucic acid or the like as a raw material. It is known that a polybasic acid compound derived from dimer acid can be obtained as a composition of a fatty acid as a raw material or a fatty acid having a trimerization or higher (for example, Patent Document 4). That is, the industrial production process of dimer acid is almost standardized in the industry, and it is obtained by quantifying unsaturated fatty acids having 11 to 22 carbon atoms with a clay catalyst or the like. The industrially obtained dimer acid is mainly composed of a dibasic acid having 36 carbon atoms obtained by dimerizing an unsaturated fatty acid having 18 carbon atoms such as oleic acid, linolenic acid and linolenic acid. Depending on the degree, it contains an arbitrary amount of monomeric acid (18 carbon atoms), trimeric acid (54 carbon atoms), and other polymerized fatty acids having 20 to 54 carbon atoms. Further, although the double bond remains after the dimerization reaction, in the present invention, the dimer acid is also included in which the degree of unsaturation is further reduced by the hydrogenation reaction. In the component dimer diamine, the terminal carboxylic acid group of the dibasic acid compound in the range of 18 to 54 carbon atoms, preferably 22 to 44 carbon atoms is replaced with a primary aminomethyl group or an amino group. It can be defined as the resulting diamine compound.

As a characteristic of dimer diamine, the property derived from the skeleton of dimer acid can be imparted. That is, since dimer diamine is an aliphatic of macromolecules having a molecular weight of about 560 to 620, the molar volume of the molecule can be increased and the polar groups of polyimide can be relatively reduced. It is considered that such a characteristic of the dimer acid type diamine contributes to improving the dielectric property by reducing the relative permittivity and the dielectric loss tangent while suppressing the decrease in the heat resistance of the polyimide. In addition, since it has two freely moving hydrophobic chains having 7 to 9 carbon atoms and two chain-like aliphatic amino groups having a length close to 18 carbon atoms, it not only gives the polyimide flexibility but also gives it flexibility. Since the polyimide can have an asymmetric chemical structure or a non-planar chemical structure, it is considered that the polyimide can have a low dielectric constant.

As the diamine diamine composition, the diamine diamine content of the component (a) is increased to 96% by weight or more, preferably 97% by weight or more, more preferably 98% by weight or more by a purification method such as molecular distillation. That's good. By setting the diamine diamine content of the component (a) to 96% by weight or more, it is possible to suppress the spread of the molecular weight distribution of the polyimide. If technically possible, it is best that all (100% by weight) of the diamine diamine composition is composed of the diamine diamine of the component (a).

(B) A monoamine compound obtained by substituting a terminal carboxylic acid group of a monobasic acid compound having 10 to 40 carbon atoms with a primary aminomethyl group or an amino group;
The monobasic acid compound in the range of 10 to 40 carbon atoms is a monobasic unsaturated fatty acid in the range of 10 to 20 carbon atoms derived from the raw material of dimer acid, and a by-product during the production of dimer acid. It is a mixture of monobasic acid compounds in the range of 21 to 40 carbon atoms. The monoamine compound is obtained by substituting the terminal carboxylic acid group of these monobasic acid compounds with a primary aminomethyl group or an amino group.

The monoamine compound of the component (b) is a component that suppresses an increase in the molecular weight of polyimide. During the polymerization of polyamic acid or polyimide, the monofunctional amino group of the monoamine compound reacts with the terminal acid anhydride group of the polyamic acid or polyimide to seal the terminal acid anhydride group, and the molecular weight of the polyamic acid or polyimide is sealed. Suppress the increase.

(C) An amine compound obtained by substituting a terminal carboxylic acid group of a polybasic acid compound having a hydrocarbon group in the range of 41 to 80 carbon atoms with a primary aminomethyl group or an amino group (however, the dimerdiamine). except for);
The polybasic acid compound having a hydrocarbon group having a carbon number of 41 to 80 is mainly composed of a tribasic acid compound having a carbon number of 41 to 80, which is a by-product during the production of dimer acid. It is a polybasic acid compound. Further, it may contain a polymerized fatty acid other than dimer acid having 41 to 80 carbon atoms. The amine compound is obtained by substituting the terminal carboxylic acid group of these polybasic acid compounds with a primary aminomethyl group or an amino group.

The amine compound of the component (c) is a component that promotes an increase in the molecular weight of polyimide. A trifunctional or higher amino group containing a triamine derived from trimeric acid as a main component reacts with a polyamic acid or a terminal acid anhydride group of polyimide to rapidly increase the molecular weight of polyimide. Further, an amine compound derived from a polymerized fatty acid other than dimer acid having 41 to 80 carbon atoms also increases the molecular weight of the polyimide and causes gelation of the polyamic acid or the polyimide.

The above diamine diamine composition facilitates confirmation of peak start, peak top and peak end of each component of the diamine diamine composition when quantification of each component by measurement using gel permeation chromatography (GPC). In addition, a sample of the diamine diamine composition treated with acetic anhydride and pyridine is used, and cyclohexanone is used as an internal standard substance. Using the sample prepared in this way, each component is quantified by the area percentage of the chromatogram of GPC. The peak start and peak end of each component are set to the minimum value of each peak curve, and the area percentage of the chromatogram can be calculated based on this.

In addition, the diamine diamine composition used in the present invention is preferably an area percent of the chromatogram obtained by GPC measurement, and the total of the components (b) and (c) is 4% or less, preferably less than 4%. By setting the total of the components (b) and (c) to 4% or less, it is possible to suppress the spread of the molecular weight distribution of the polyimide.

The area percentage of the chromatogram of the component (b) is preferably 3% or less, more preferably 2% or less, still more preferably 1% or less. By setting it in such a range, it is possible to suppress a decrease in the molecular weight of the polyimide, and further widen the range of the molar ratio of the tetracarboxylic acid anhydride component and the diamine component. The component (b) may not be contained in the diamine diamine composition.

The area percentage of the chromatogram of the component (c) is 2% or less, preferably 1.8% or less, and more preferably 1.5% or less. Within such a range, it is possible to suppress a rapid increase in the molecular weight of the polyimide, and further suppress an increase in the dielectric loss tangent of the resin film at a wide frequency range. The component (c) may not be contained in the diamine diamine composition.

When the area percent ratio (b / c) of the chromatograms of the components (b) and (c) is 1 or more, the molar ratio of the tetracarboxylic acid anhydride component and the diamine component (tetracarboxylic acid anhydride component /). The diamine component) is preferably 0.97 or more and less than 1.0, and such a molar ratio makes it easier to control the molecular weight of the polyimide.

Further, when the ratio (b / c) of the area percent of the chromatograms of the components (b) and (c) is less than 1, the molar ratio of the tetracarboxylic acid anhydride component and the diamine component (tetracarboxylic acid anhydride component). The / diamine component) is preferably 0.97 or more and 1.1 or less, and by setting such a molar ratio, it becomes easier to control the molecular weight of the polyimide.

The diamine diamine composition is preferably purified for the purpose of reducing the component (a) other than the diamine diamine. The purification method is not particularly limited, but a known method such as a distillation method or precipitation purification is preferable. The diamine diamine composition before purification can be obtained as a commercially available product, and examples thereof include PRIAMINE 1073 (trade name), PRIAMINE 1074 (trade name), and PRIAMINE 1075 (trade name) manufactured by Croda Japan.

Examples of the diamine compound other than the aliphatic diamine used for the polyimide include aromatic diamine compounds. Specific examples thereof include 1,4-diaminobenzene (p-PDA; paraphenylenediamine), 2,2-bis- [4- (4-aminophenoxy) phenyl] propane), 4,4'-diaminodiphenyl ether, and the like. 1,3-Bis (4-aminophenoxy) benzene, 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), 2,2'-n-propyl-4,4'-diaminobiphenyl ( m-NPB), 4-aminophenyl-4'-aminobenzoate (APAB), 2,2-bis- [4- (3-aminophenoxy) phenyl] propane, bis [4- (3-aminophenoxy) phenyl] Sulfon, bis [4- (3-aminophenoxy)] biphenyl, bis [1- (3-aminophenoxy)] biphenyl, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (3-amino) Phenoxy) phenyl] ether, bis [4- (3-aminophenoxy)] benzophenone, 9,9-bis [4- (3-aminophenoxy) phenyl] fluorene, 2,2-bis- [4- (4-amino) Phenoxy) phenyl] hexafluoropropane, 2,2-bis- [4- (3-aminophenoxy) phenyl] hexafluoropropane, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-methylenedi -o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4'-methylene-2,6-diethylaniline, 3,3'-diaminodiphenylethane, 3,3'-diaminobiphenyl, 3 , 3'-dimethoxybenzidine, 3,3''-diamino-p-terphenyl, 4,4'-[1,4-phenylenebis (1-methylethylidene)] bisaniline, 4,4'-[1,3' -Phenylene bis (1-methylethylidene)] bisaniline, bis (p-aminocyclohexyl) methane, bis (p-β-amino-t-butylphenyl) ether, bis (p-β-methyl-δ-aminopentyl) benzene , P-bis (2-methyl-4-aminopentyl) benzene, p-bis (1,1-dimethyl-5-aminopentyl) benzene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4 -Bis (β-amino-t-butyl) toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylene diamine, p-xylylene Amin, 2,6-diaminopyridine, 2,5-Diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, 2'-methoxy-4,4'-diaminobenzanilide, 4,4'-diaminobenzanilide, 1, Diamine compounds such as 3-bis [2- (4-aminophenyl) -2-propyl] benzene, 6-amino-2- (4-aminophenoxy) benzoxazole, 1,3-bis (3-aminophenoxy) benzene Can be mentioned.

The polyimide can be produced by reacting the above-mentioned tetracarboxylic acid anhydride component and the diamine component in a solvent to generate polyamic acid, and then heating and closing the ring. For example, a polyimide precursor is obtained by dissolving a tetracarboxylic acid anhydride component and a diamine component in an organic solvent in approximately equimolar amounts, stirring at a temperature in the range of 0 to 100 ° C. for 30 minutes to 24 hours, and carrying out a polymerization reaction. Polyamic acid is obtained. In the reaction, the reaction components are dissolved in the organic solvent so that the precursor to be produced is in the range of 5 to 50% by weight, preferably in the range of 10 to 40% by weight. Examples of the organic solvent used in the polymerization reaction include N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N, N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2 -Butanone, dimethyl sulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethylsulfate, cyclohexanone, methylcyclohexane, dioxane, tetrahydrofuran, diglime, triglime, methanol, ethanol, benzyl alcohol, cresol and the like can be mentioned. Two or more of these solvents can be used in combination, and aromatic hydrocarbons such as xylene and toluene can be used in combination. The amount of such an organic solvent used is not particularly limited, but it should be adjusted so that the concentration of the polyamic acid solution obtained by the polymerization reaction is about 5 to 50% by weight. Is preferable.

The synthesized polyamic acid is usually advantageous to be used as a reaction solvent solution, but can be concentrated, diluted or replaced with another organic solvent if necessary. In addition, polyamic acid is generally excellent in solvent solubility, and is therefore advantageously used. The viscosity of the polyamic acid solution is preferably in the range of 500 cps to 100,000 cps. If it is out of this range, defects such as uneven thickness and streaks are likely to occur in the film during coating work by a coater or the like.

The method of imidizing the polyamic acid to form the polyimide is not particularly limited, and for example, a heat treatment such as heating in the solvent at a temperature in the range of 80 to 400 ° C. for 1 to 24 hours is preferably adopted. Will be done. Further, the temperature may be heated under a constant temperature condition, or the temperature may be changed in the middle of the process.

By selecting the types of the tetracarboxylic acid anhydride component and the diamine component in the polyimide of the component (A) and the molar ratio of each when two or more types of the tetracarboxylic acid anhydride component or the diamine component are applied. It is possible to control the dielectric property, thermal expansion coefficient, tensile elasticity, glass transition temperature, and the like. Further, when the polyimide of the component (A) has a plurality of structural units of the polyimide, it may exist as a block or may exist randomly, but it is preferable that the polyimide exists randomly.

The imide group concentration of the polyimide of the component (A) is preferably 22% by weight or less, more preferably 20% by weight or less. Here, the "imide group concentration" means a value obtained by dividing the molecular weight of the imide base portion (-(CO) ₂ -N-) in the polyimide by the molecular weight of the entire structure of the polyimide. When the imide group concentration exceeds 22% by weight, the molecular weight of the resin itself becomes small, the low hygroscopicity deteriorates due to the increase in polar groups, and the Tg and the tensile elastic modulus increase.

The polyimide of the component (A) most preferably has a completely imidized structure. However, a part of the polyimide may be an amic acid. The imidization rate is determined by measuring the infrared absorption spectrum of the polyimide thin film by the single reflection ATR method using a Fourier transform infrared spectrophotometer (commercially available product: manufactured by Nippon Spectroscopy Co., Ltd., trade name; FT / IR620). It can be calculated from the absorbance of C = O expansion and contraction derived from the imide group of 1780 cm ^-1 with the benzene ring absorber near 1015 cm ^-1 as a reference.

The weight average molecular weight of the polyimide is preferably in the range of, for example, 10,000 to 200,000, and if it is within such a range, the weight average molecular weight of the polyimide can be easily controlled.
Further, for example, when applied as an adhesive for FPC, the weight average molecular weight of the polyimide is more preferably in the range of 20,000 to 150,000, and further preferably in the range of 40,000 to 150,000. When the weight average molecular weight of the polyimide is less than 20,000, the flow resistance tends to deteriorate. On the other hand, when the weight average molecular weight of polyimide exceeds 150,000, the viscosity increases excessively and becomes insoluble in a solvent, and defects such as uneven thickness of the adhesive layer and streaks tend to occur during coating work. Become.
Since the weight average molecular weight greatly fluctuates due to the formation of the crosslink described later, it is preferable that the polyimide before the formation of the crosslink satisfies the above weight average molecular weight.

<Component (B): Magnesium oxide filler>
The magnesium oxide filler of the component (B) is a filler containing magnesium oxide (MgO; magnesia) as a main component, and magnesium oxide is 95.0% by weight or more, preferably 98% by weight or more, and more preferably 99% by weight or more. Most preferably, it contains 99.9% by weight or more. The higher the purity of magnesium oxide constituting the filler, the better the dispersibility even if the average particle size is small, and it is easy to obtain the effect of improving the solder heat resistance and peel strength while maintaining a low dielectric loss tangent. The magnesium oxide forming the filler may be a single crystal or a polycrystal, but a single crystal is preferable because excellent dispersibility can be obtained even if the average particle size is small. By blending the magnesium oxide filler with the resin composition, the solder heat resistance and the peel strength can be enhanced without deteriorating the dielectric loss tangent when the resin film is formed.

The magnesium oxide filler has an average particle size in the range of 30 nm to 10 μm, preferably in the range of 30 nm to less than 10 μm, more preferably in the range of 30 nm to 5 μm, and further preferably in the range of 30 nm to 1 μm. Most preferably, it is in the range of 40 nm to 300 nm. Within this range, it is possible to effectively improve the solder heat resistance and the peel strength without deteriorating the dielectric properties when the resin film is formed. If the average particle size is less than 30 nm, the dispersibility deteriorates and it becomes difficult to form a resin film, or when the resin film is formed, it becomes difficult to disperse uniformly, resulting in deterioration of dielectric properties. , May cause deterioration of solder heat resistance and peel strength. If the average particle size exceeds 10 μm, voids may be generated due to an increase in stress due to shrinkage of the surrounding resin when the film is formed, and may appear as irregularities on the surface of the film and deteriorate the smoothness of the film surface. Here, the BET-equivalent particle size is applied to the magnesium oxide filler having a particle size of less than 0.4 μm, and the volume-based particle size distribution by the laser diffraction method is applied to the magnesium oxide filler having a particle size of 0.4 μm or more. Apply the particle size obtained by the measurement.

In particular, magnesium oxide fillers having an average particle size (here, the average particle size means a BET-equivalent particle size, hereinafter referred to as “BET-equivalent particle size”) in the range of 30 nm to 300 nm have a small particle size. Nevertheless, it is most preferable because it has excellent dispersibility in the polyimide composition (resin solution) and the resin film, and has a great effect of improving solder heat resistance and peel strength. The reason why magnesium oxide fillers having a BET-equivalent particle size in the range of 30 nm to 300 nm is effective in improving solder heat resistance and peel strength is not yet clear, but the following speculations (1) to (3) are made. It is possible.
(1) Since the particle size is small, excessive concentration of stress does not occur in a state of being dispersed in polyimide, which is a matrix resin, and crazes (fine cracks) occur, but large cracks are unlikely to occur.
(2) When the matrix resin is deformed, many small pores are formed around the filler particles, and these many pores improve the elongation, and as a result, the stress concentration is relaxed and the craze is stabilized. To be done.
(3) Since the magnesium oxide filler has a low coefficient of thermal expansion (CTE) of about 13 ppm / K, it is possible to suppress the thermal expansion of the polyimide film at high temperatures and relieve the stress at the interface with the metal layer.

Magnesium oxide fillers having a BET-equivalent particle size in the range of 30 nm to 300 nm are produced by gas-phase oxidation reaction of high-purity metallic magnesium vapor and oxygen to generate crystal nuclei and growing the crystal nuclei. .. Therefore, since it is a single crystal and the purity of magnesium oxide is high, it is considered that it has the above-mentioned characteristics.

On the other hand, aluminum oxide (alumina) fillers, which are widely used in the field of electronic materials, have higher interfacial energy than magnesium oxide fillers, and therefore have poor handleability when the BET-equivalent particle size is in the range of 30 nm to 300 nm. , It is difficult to apply to polyimide, it has poor wettability with resin, and it is not stable even if there are pores, so it has the effect of improving solder heat resistance and peel strength like magnesium oxide filler. It is thought that it cannot be done.

The average particle size of the magnesium oxide filler may be in the range of 200 nm to 10 μm depending on the purpose. In addition, the "particle diameter" of the magnesium oxide filler can be calculated based on the diameter in the case of a spherical shape, and can be calculated based on the major axis of the filler particles in the case of other shapes such as a plate shape. can.

Further, as shown in the test example described later, the magnesium oxide filler has a weight loss rate of 2% or less at 350 ° C. when heated from 30 ° C. to 450 ° C. at a heating rate of 10 ° C. per minute in thermogravimetric analysis measurement. It is preferably 1.8% or less, and more preferably 1.8% or less. The fact that the weight loss rate in this temperature range is 2% or less means that the dehydration decomposition of magnesium hydroxide [Mg (OH) ₂ ] hardly occurs, and the content of magnesium hydroxide in the magnesium oxide filler is contained. It means that the amount is very small. Here, magnesium hydroxide is mixed in during the production process or is generated by hydration of the surface of magnesium oxide due to the influence of environmental humidity during storage after production. In the present invention, magnesium hydroxide is generated. It is preferable to use a magnesium oxide filler having a reduced magnesium content as much as possible.

Further, as shown in the test examples described later, it is preferable that the magnesium oxide filler is such that a peak derived from magnesium oxide is detected and a peak derived from magnesium hydroxide is not detected in the X-ray diffraction (XRD) measurement. .. When the magnesium oxide filler is measured by the X-ray diffractometry, it can be determined that the magnesium oxide filler does not substantially contain magnesium hydroxide because the peak derived from magnesium hydroxide is not detected. Here, "substantially free of magnesium hydroxide" means that the content of magnesium hydroxide in the magnesium oxide filler is 0.1% by weight or less.

The shape of the magnesium oxide filler is not particularly limited, and may be, for example, a plate shape, a spherical shape, or a polyhedral shape typified by a cube. Here, "plate-like" is used in the sense of including, for example, flat, flat, flaky, scaly, etc., and the thickness of the filler is sufficiently smaller than the major axis or the minor axis of the flat surface portion, preferably 1. / 2 or less.

The magnesium oxide filler may be surface-treated. A known technique can be used for the surface treatment, and for example, modification by corona treatment, plasma treatment, UV treatment or the like, functionalization treatment using a silane coupling agent or the like, or the like is preferable. By surface-treating the magnesium oxide filler, it is possible to improve the affinity with the solvent or polyamic acid and improve the repulsive force between the filler particles, and the dispersibility of the magnesium oxide filler and the long-term varnish Stability is improved.

As the magnesium oxide filler, a commercially available product can be appropriately selected and used. As commercially available magnesium oxide fillers, for example, high-purity ultrafine powder Magnesia 2000A (trade name), 500A (trade name), RF-10CS (trade name), RF-10CS-SC (trade name) manufactured by Ube Material Industries Ltd. Etc. can be used.

[Mixing amount]
The weight ratio of the component (B) to the total amount of the component (A) and the component (B) in the resin composition is in the range of 1 to 50% by weight, preferably in the range of 10 to 45% by weight, and is preferably 15 to. The range of 40% by weight is more preferable. If the weight ratio of the component (B) to the total amount of the component (A) and the component (B) is less than 1% by weight, the improvement of the solder heat resistance and the peel strength may be insufficient. On the other hand, when the weight ratio of the component (B) exceeds 50% by weight, the adhesiveness when the resin film is formed is lowered, or the resin film becomes brittle and the bendability is lowered. Further, when the weight ratio of the component (B) exceeds 50% by weight, the viscosity of the resin composition becomes high and the workability is lowered. Further, when the magnesium oxide filler having a BET-equivalent particle size in the range of 30 nm to 60 nm is contained, (B) with respect to the total amount of the component (A) and the component (B) from the viewpoint of suppressing the aggregation of the magnesium oxide filler. ) The weight ratio of the components is preferably 10% by weight or less, more preferably 5% by weight or less.
When the cross-linking amino compound described below is blended, the weight ratio of the component (B) is calculated by using the total weight including the cross-linking amino compound in the weight of the component (A).

[Arbitrary ingredient]
When the polyimide of the component (A) has a ketone group, the amino compound having the ketone group and at least two primary amino groups as functional groups (referred to as "cross-linking amino compound" in the present specification. A crosslinked structure can be formed by reacting the amino groups of (there is) to form a C = N bond. By forming the crosslinked structure, the heat resistance of the thermoplastic polyimide forming the adhesive layer can be improved. Therefore, the resin composition of the present embodiment can contain an amino compound for forming a crosslink as an optional component.

A preferred tetracarboxylic acid anhydride for forming a polyimide having a ketone group is, for example, 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA), and a diamine compound is, for example, 4 Aromatic diamines such as, 4'-bis (3-aminophenoxy) benzophenone (BABP), 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene (BABB) can be mentioned. For the purpose of forming a crosslinked structure, the resin composition of the present embodiment particularly contains, preferably 50 mol% or more, more preferably 50 mol% or more of the BTDA residue derived from BTDA with respect to the total tetracarboxylic acid residue. It is preferable to contain the polyimide of the component (A) contained in an amount of 60 mol% or more and the amino compound for forming a crosslink.

Examples of the crosslink-forming amino compound include (I) a dihydrazide compound, (II) an aromatic diamine, and (III) an aliphatic amine. Among these, the dihydrazide compound is preferable. Aliphatic amines other than dihydrazide compounds tend to form crosslinked structures even at room temperature, and there is a concern about the storage stability of varnishes, while aromatic diamines need to be heated to a high temperature in order to form crosslinked structures. As described above, when the dihydrazide compound is used, both the storage stability of the varnish and the shortening of the curing time can be achieved at the same time. Examples of the dihydrazide compound include dihydrazide oxalic acid, dihydrazide malonate, dihydrazide succinic acid, dihydrazide glutaric acid, dihydrazide adipic acid, dihydrazide pymeric acid, dihydrazide dihydric acid, dihydrazide azeline acid, dihydrazide sevacinate, and dihydrazide sevacinate. Dihydrazide, dihydrazide humalic acid, diglycolic acid dihydrazide, tartrate dihydrazide, apple acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2,6-naphthoediodic acid dihydrazide, 4,4-bisbenzenedihydrazide, 1,4 -Dihydrazide compounds such as naphthoediic acid dihydrazide, 2,6-pyridinediic acid dihydrazide, and itaconic acid dihydrazide are preferable. The above dihydrazide compounds may be used alone or in combination of two or more.

Further, the amino compounds such as (I) dihydrazide compound, (II) aromatic diamine, and (III) aliphatic amine are, for example, a combination of (I) and (II), a combination of (I) and (III), and the like. It is also possible to use two or more kinds in combination across categories, such as the combination of (I), (II) and (III).

Further, from the viewpoint of making the network-like structure formed by the cross-linking by the cross-linking amino compound more dense, the cross-linking amino compound used in the present invention has a molecular weight (when the cross-linking amino compound is an oligomer). The weight average molecular weight) is preferably 5,000 or less, more preferably 90 to 2,000, still more preferably 100 to 1,500. Among these, an amino compound for forming a crosslink having a molecular weight of 100 to 1,000 is particularly preferable. When the molecular weight of the cross-linking amino compound is less than 90, one amino group of the cross-linking amino compound only forms a C = N bond with the ketone group of the polyimide resin, and the periphery of the remaining amino groups is sterically formed. Due to the bulkiness, the remaining amino groups tend to be difficult to form a C = N bond.

In the case of cross-linking the ketone group in the polyimide of the component (A) and the amino compound for cross-linking, the amino compound for cross-linking is added to the resin solution containing the component (A) to form a cross-linking group in the polyimide. A condensation reaction is carried out with the primary amino group of the amino compound for forming a crosslink. By this condensation reaction, the resin solution is cured to become a cured product. In this case, the amount of the amino compound for forming a bridge is 0.004 mol to 1.5 mol, preferably 0.005 mol to 1.2 mol, in total for the primary amino group with respect to 1 mol of the ketone group. It can be more preferably 0.03 mol to 0.9 mol, and most preferably 0.04 mol to 0.6 mol. If the amount of the cross-linking amino compound added so that the total number of primary amino groups is less than 0.004 mol per 1 mol of ketone group, the cross-linking by the cross-linking amino compound is not sufficient, so that after curing, the cross-linking is not sufficient. When the amount of the cross-linking amino compound added exceeds 1.5 mol, the unreacted cross-linking amino compound acts as a thermoplastic and the heat resistance of the adhesive layer is lowered. Tend to let.

The conditions for the condensation reaction for the formation of a crosslink are the condition that the ketone group in the polyimide of the component (A) reacts with the primary amino group of the amino compound for forming a crosslink to form an imine bond (C = N bond). If there is, there is no particular limitation. The temperature of the heat condensation is set for the purpose of releasing the water generated by the condensation to the outside of the system, or for simplifying the condensation step when the heat condensation reaction is subsequently performed after the synthesis of the polyimide of the component (A). For example, the range of 120 to 220 ° C. is preferable, and the range of 140 to 200 ° C. is more preferable. The reaction time is preferably about 30 minutes to 24 hours. The end point of the reaction is the absorption derived from the ketone group in the polyimide resin near 1670 cm ^-1 by measuring the infrared absorption spectrum using, for example, a Fourier transform infrared spectrophotometer (commercially available product: FT / IR620 manufactured by Nippon Spectroscopy). It can be confirmed by the decrease or disappearance of the peak and the appearance of the absorption peak derived from the imine group near 1635 cm ^-1 .

The heat condensation between the ketone group of the polyimide of the component (A) and the primary amino group of the amino compound for forming a crosslink is, for example,
(1) A method of adding and heating an amino compound for forming a crosslink, following the synthesis (imidization) of the polyimide of the component (A).
(2) An excess amount of an amino compound is charged in advance as a diamine component, and following the synthesis (imidization) of the polyimide of the component (A), the remaining amino compounds that are not involved in imidization or amidization are used as an amino compound for cross-linking. A method of heating with polyimide, or
(3) A method of heating a resin composition to which an amino compound for forming a crosslink is added after processing it into a predetermined shape (for example, after applying it to an arbitrary substrate or forming it into a film).
It can be done by such as.

In order to impart heat resistance to the polyimide of the component (A), the formation of an imine bond was described by forming a crosslinked structure, but the present invention is not limited to this, and as a method for curing the polyimide of the component (A), for example, an epoxy resin. , Epoxy resin curing agent, maleimide, activated ester resin, resin having a styrene skeleton, and other compounds having unsaturated bonds can be blended and cured.

In the resin composition of the present embodiment, if necessary, as an optional component, an inorganic filler other than magnesium oxide, an organic filler, a plasticizer, a curing accelerator, a coupling agent, etc. Pigments, flame retardants and the like can be appropriately blended. Here, examples of the inorganic filler other than magnesium oxide include aluminum oxide, beryllium oxide, niobium oxide, titanium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, magnesium fluoride, and potassium fluoride. , Phosphinic acid metal salt and the like. These can be used alone or in admixture of two or more. Further, as an optional component, another resin component such as an epoxy resin, a fluororesin, or an olefin resin may be blended.

Further, the resin composition of the present embodiment can contain a solvent such as an organic solvent. Since the polyimide component (A) is solvent-soluble, the resin composition can be a polyimide solution (varnish) containing a solvent. Examples of the organic solvent include N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N, N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2-butanone, and dimethyl. Examples thereof include sulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethylformamide, cyclohexanone, dioxane, tetrahydrofuran, diglime, triglime, cresol and the like. Two or more of these solvents can be used in combination, and aromatic hydrocarbons such as xylene and toluene can be used in combination. The content of the solvent is not particularly limited, but it is preferable to adjust the content so that the concentration of the polyamic acid or the polyimide is about 5 to 30% by weight.

[viscosity]
The viscosity of the resin composition is preferably in the range of, for example, 3000 cps to 100,000 cps as the viscosity range in which the handleability when the resin composition is applied is improved and a coating film having a uniform thickness is easily formed. It is more preferably within the range of 50,000 cps. If it is out of the above viscosity range, defects such as thickness unevenness and streaks are likely to occur in the film during coating work by a coater or the like.

[Preparation of resin composition]
In preparing the resin composition, for example, the magnesium oxide filler may be directly added to the resin solution of polyamic acid or polyimide prepared by using an arbitrary solvent. Alternatively, in consideration of the dispersibility of the magnesium oxide filler, the magnesium oxide filler is mixed in advance with the reaction solvent containing either one of the acid dianhydride component and the diamine component, which are the raw materials of the polyamic acid, and then the other is stirred. The raw material of the above may be added to proceed with the polymerization. In either method, the entire amount of magnesium oxide filler may be added at one time, or may be added little by little in several divided times. In addition, the raw materials may be added all at once, or may be divided into several times and mixed little by little.

The resin composition of the present embodiment has excellent flexibility and thermoplasticity when an adhesive layer is formed by using the resin composition. Therefore, for example, in FPCs, rigid flex circuit boards, etc., it has preferable properties for applications such as an adhesive layer material and an adhesive for a coverlay film that protects a wiring portion.

[Resin film]
The resin film of the present embodiment is a resin film composed of a single layer or a plurality of layers including a filler-containing thermoplastic resin layer, and the filler-containing thermoplastic resin layer is the solid content (excluding the solvent) of the resin composition. The rest) is made into a film as the main component. That is, the filler-containing thermoplastic resin layer has the component (A) and the component (B);
(A) Polyimide obtained by reacting a tetracarboxylic acid anhydride component with a diamine component, and (B) a magnesium oxide filler having an average particle size in the range of 30 nm to 10 μm.
The content of the component (B) with respect to the total amount of the component (A) and the component (B) is in the range of 1 to 50% by weight. The resin film of the present embodiment has excellent high frequency characteristics and excellent adhesiveness (particularly solder heat resistance and peel strength), and can be preferably used as an insulating resin layer for a circuit board such as an FPC. The insulating resin layer of the circuit board includes an adhesive layer and a coverlay film material in addition to the insulating base material.

The resin film of the present embodiment is not particularly limited as long as it is an insulating resin film containing the filler-containing thermoplastic resin layer described above, and may be a film (sheet) made of an insulating resin, and may be a copper foil. , A glass plate, a polyimide film, a polyamide film, a resin sheet such as a polyester film, or the like may be an insulating resin film laminated on a base material.

(Relative permittivity)
The resin film of the present embodiment is provided under constant temperature and humidity conditions of 23 ° C. and 50% RH in order to ensure impedance matching when used for a circuit board such as FPC and to reduce electrical signal loss. The relative permittivity (ε) at 10 GHz after humidity control for 24 hours is preferably 3.3 or less, more preferably 3.1 or less. If this relative permittivity exceeds 3.3, inconveniences such as loss of electric signals are likely to occur on the transmission path of high-frequency signals when used for a circuit board such as an FPC.

(Dissipation factor)
Further, the resin film of the present embodiment is subjected to humidity control for 24 hours under constant temperature and humidity conditions of 23 ° C. and 50% RH in order to reduce the loss of electric signals when used for a circuit board such as FPC. When the dielectric loss tangent (Tanδ) at 10 GHz is 40 mol% or more of the aliphatic diamine as the raw material diamine compound, it is preferably 0.0022 or less, more preferably 0.0020 or less. If the dielectric loss tangent exceeds 0.0022, inconveniences such as loss of electric signals are likely to occur on the transmission path of high-frequency signals when used for a circuit board such as an FPC. On the other hand, when only aromatic diamine is used as the raw material diamine compound, the dielectric loss tangent is preferably 0.015 or less, more preferably 0.010 or less.

(Glass-transition temperature)
When 40 mol% or more of the aliphatic diamine is used as the raw material diamine compound in the resin film of the present embodiment, the glass transition temperature (Tg) is preferably 250 ° C. or lower, and is in the range of 40 ° C. or higher and 200 ° C. or lower. It is more preferable to be inside. When the Tg of the resin film is 250 ° C. or lower, thermocompression bonding at a low temperature becomes possible, so that the internal stress generated during laminating can be alleviated and the dimensional change after circuit processing can be suppressed. If the Tg of the resin film exceeds 250 ° C., the bonding temperature becomes high, which may impair the dimensional stability after circuit processing.

(Thickness)
The thickness of the resin film of the present embodiment is preferably in the range of, for example, 5 μm or more and 125 μm or less, and more preferably in the range of 8 μm or more and 100 μm or less. If the thickness of the resin film is less than 5 μm, problems such as wrinkles may occur during transportation in the production of the resin film, while if the thickness of the resin film exceeds 125 μm, the productivity of the resin film may decrease. There is.

(Tension modulus)
The resin film of the present embodiment preferably has a tensile elastic modulus in the range of 0.1 GPa to 3.0 GPa from the viewpoints of reducing wrinkles, preventing air bubbles from being caught during laminating, and handling properties. The range of 0.2 GPa to 2.0 GPa is more preferable.

(Maximum elongation)
The resin film of the present embodiment preferably has a maximum elongation in the range of 30% to 200%, preferably 60% to 160, from the viewpoint of bendability and crack prevention when applied as an insulating resin layer of FPC. The range of% is more preferable.

Since the resin film of the present embodiment has low dielectric adjacency and excellent adhesiveness, the adhesive layer in the coverlay film, the circuit board, the multilayer circuit board, the adhesive layer in the copper foil with resin, and the bond ply. It is useful as a bonding sheet or the like.

[Laminate]
The laminate according to the embodiment of the present invention has a base material and an adhesive layer laminated on at least one surface of the base material, and the adhesive layer is made of the above resin film. .. The laminated body may include any layer other than the above. Examples of the base material in the laminate include a base material of an inorganic material such as a copper foil and a glass plate, and a base material of a resin material such as a polyimide film, a polyamide film, and a polyester film.
Preferred embodiments of the laminate include a coverlay film, a copper foil with a resin, and the like.

[Coverlay film]
The coverlay film, which is one aspect of the laminated body, has a coverlay film material layer as a base material and an adhesive layer laminated on one side of the coverlay film material layer, and is an adhesive layer. Is made of the above resin film. The coverlay film may contain any layer other than the above.

The material of the coverlay film material layer is not particularly limited, and for example, a polyimide-based film such as a polyimide resin, a polyetherimide resin, or a polyamide-imide resin, a polyamide-based film, or a polyester-based film can be used. Among these, it is preferable to use a polyimide film having excellent heat resistance. Further, the coverlay film material may contain a black pigment in order to effectively exhibit light-shielding property, concealing property, design property, etc., and the surface of the film material may contain a black pigment as long as the effect of improving the dielectric property is not impaired. It can contain any component such as a matte pigment that suppresses gloss.

The thickness of the coverlay film material layer is not particularly limited, but is preferably in the range of, for example, 5 μm or more and 100 μm or less.
The thickness of the adhesive layer is not particularly limited, but is preferably in the range of, for example, 10 μm or more and 75 μm or less.

The coverlay film of the present embodiment can be manufactured by the method exemplified below.
First, as a first method, a varnish-like adhesive composition containing a solvent is applied to one side of a film material layer for coverlay, and then dried at a temperature of, for example, 80 to 180 ° C. to form an adhesive layer. By forming, a coverlay film having a coverlay film material layer and an adhesive layer can be formed.

Further, as a second method, an adhesive layer in the form of a varnish containing a solvent is applied onto an arbitrary substrate, dried at a temperature of, for example, 80 to 180 ° C., and then peeled off. A coverlay film can be formed by forming a resin film for use and thermocompression bonding the resin film with a film material layer for coverlay at a temperature of, for example, 60 to 220 ° C.

[Copper foil with resin]
A copper foil with a resin, which is another aspect of the laminated body, is obtained by laminating an adhesive layer on at least one side of a copper foil as a base material, and the adhesive layer is made of the above resin film. The copper foil with resin of the present embodiment may contain any layer other than the above.

The thickness of the adhesive layer in the resin-attached copper foil is preferably in the range of, for example, 2 to 125 μm, and more preferably in the range of 2 to 100 μm. If the thickness of the adhesive layer does not reach the above lower limit, there may be a problem that sufficient adhesiveness cannot be guaranteed. On the other hand, if the thickness of the adhesive layer exceeds the above upper limit value, problems such as deterioration of dimensional stability occur. Further, from the viewpoint of low dielectric constant and low dielectric loss tangent, the thickness of the adhesive layer is preferably 3 μm or more.

The material of the copper foil in the copper foil with resin is preferably one containing copper or a copper alloy as a main component. The thickness of the copper foil is preferably 35 μm or less, more preferably in the range of 5 to 25 μm. From the viewpoint of production stability and handleability, the lower limit of the thickness of the copper foil is preferably 5 μm. The copper foil may be rolled copper foil or electrolytic copper foil. Further, as the copper foil, a commercially available copper foil can be used.

The copper foil with resin may be prepared, for example, by sputtering a metal on a resin film to form a seed layer and then forming a copper layer by, for example, copper plating, or heat the resin film and the copper foil. It may be prepared by laminating by a method such as crimping. Further, in order to form an adhesive layer on the copper foil, the copper foil with resin may be prepared by casting a coating liquid of the resin composition, drying it to form a coating film, and then performing necessary heat treatment. good.

[Metal-clad laminate]
(First aspect)
The metal-clad laminate according to the embodiment of the present invention includes an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer, and at least one layer of the insulating resin layer is described above. It is made of a resin film. The metal-clad laminate of the present embodiment may include any layer other than the above.

(Second aspect)
The metal-clad laminate according to another embodiment of the present invention is, for example, an insulating resin layer, an adhesive layer laminated on at least one surface of the insulating resin layer, and an insulating resin layer via the adhesive layer. It is a so-called three-layer metal-clad laminate provided with a laminated metal layer M, and the adhesive layer is made of the above resin film. The three-layer metal-clad laminate may include any layer other than the above. In the three-layer metal-clad laminate, the adhesive layer may be provided on one side or both sides of the insulating resin layer, and the metal layer M is provided on one side or both sides of the insulating resin layer via the adhesive layer. Just do it. That is, the three-layer metal-clad laminate may be a single-sided metal-clad laminate or a double-sided metal-clad laminate. A single-sided FPC or a double-sided FPC can be manufactured by processing a wiring circuit by etching the metal layer M of the three-layer metal-clad laminate.

The insulating resin layer in the three-layer metal-clad laminate is not particularly limited as long as it is composed of a resin having electrical insulating properties, and is, for example, polyimide, epoxy resin, phenol resin, polyethylene, polypropylene, polytetrafluoroethylene. , Silicone, ETFE and the like, but it is preferably composed of polyimide. The polyimide layer constituting the insulating resin layer may be a single layer or a plurality of layers, but preferably includes a non-thermoplastic polyimide layer.

The thickness of the insulating resin layer in the three-layer metal-clad laminate is preferably in the range of, for example, 1 to 125 μm, and more preferably in the range of 5 to 100 μm. If the thickness of the insulating resin layer does not reach the above lower limit, there may be a problem that sufficient electrical insulation cannot be guaranteed. On the other hand, if the thickness of the insulating resin layer exceeds the above upper limit value, problems such as warpage of the metal-clad laminated board are likely to occur.

The thickness of the adhesive layer in the three-layer metal-clad laminate is preferably in the range of, for example, 0.1 to 125 μm, and more preferably in the range of 0.3 to 100 μm. In the three-layer metal-clad laminate of the present embodiment, if the thickness of the adhesive layer does not reach the above lower limit value, there may be a problem that sufficient adhesiveness cannot be guaranteed. On the other hand, if the thickness of the adhesive layer exceeds the above upper limit value, problems such as deterioration of dimensional stability occur. Further, from the viewpoint of reducing the dielectric constant and the low dielectric loss tangent of the entire insulating layer, which is a laminate of the insulating resin layer and the adhesive layer, the thickness of the adhesive layer is preferably 3 μm or more.

The ratio of the thickness of the insulating resin layer to the thickness of the adhesive layer (thickness of the insulating resin layer / thickness of the adhesive layer) is preferably in the range of, for example, 0.1 to 3.0, and is preferably 0.15 to 2. The range of 0.0 is more preferable. By setting such a ratio, it is possible to suppress the warp of the three-layer metal-clad laminate. Further, the insulating resin layer may contain a filler, if necessary. Examples of the filler include silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, and metal salts of organic phosphinic acid. These can be used alone or in admixture of two or more.

[Circuit board]
The circuit board according to the embodiment of the present invention is formed by wiring the metal layer of the metal-clad laminate according to any one of the above embodiments. A circuit board such as an FPC can be manufactured by processing one or more metal layers of a metal-clad laminate into a pattern by a conventional method to form a wiring layer (conductor circuit layer). The circuit board may include a coverlay film that covers the wiring layer.

Examples are shown below, and the features of the present invention will be described more specifically. However, the scope of the present invention is not limited to the examples. In the following examples, various measurements and evaluations are as follows unless otherwise specified.

[Measuring method of amine value]
Approximately 2 g of the dimerdiamine composition is weighed in a 200-250 mL triangular flask, using phenolphthalein as an indicator, and a 0.1 mol / L ethanolic potassium hydroxide solution is added dropwise until the solution turns pale pink. Dissolve in about 100 mL of neutralized butanol. Add 3 to 7 drops of phenolphthalein solution to it, and titrate with stirring with 0.1 mol / L ethanolic potassium hydroxide solution until the sample solution turns pale pink. Add 5 drops of bromophenol blue solution to it, and titrate with stirring with 0.2 mol / L hydrochloric acid / isopropanol solution until the sample solution turns yellow.
The amine value is calculated by the following formula (1).
Amine value = {(V ₂ x C ₂ )-(V ₁ x C ₁ )} x M _KOH / m ... (1)
Here, the amine value is a value expressed in mg-KOH / g, and M _KOH has a molecular weight of potassium hydroxide of 56.1. V and C are the volumes and concentrations of the solutions used for titration, respectively, and the subscripts 1 and 2 are 0.1 mol / L ethanolic potassium hydroxide solution and 0.2 mol / L hydrochloric acid / isopropanol solution, respectively. Represents. Further, m is the sample weight expressed in grams.

[Measurement of Weight Average Molecular Weight (Mw) of Polyimide]
The weight average molecular weight was measured by a gel permeation chromatograph (manufactured by Tosoh Corporation, trade name; HLC-8220GPC was used). Polystyrene was used as a standard substance, and tetrahydrofuran (THF) was used as a developing solvent.

[Calculation of area percentage of GPC and chromatogram]
GPC prepared a sample by diluting a 100 mg solution of 20 mg dimerdiamine composition pretreated with 200 μL acetic anhydride, 200 μL pyridine and 2 mL THF with 10 mL THF (containing 1000 ppm cyclohexanone). The prepared sample was manufactured by Tosoh Corporation, trade name: HLC-8220GPC, column: TSK-gel G2000HXL, G1000HXL, flow volume: 1 mL / min, column (oven) temperature: 40 ° C., injection volume: 50 μL. Measured at. Cyclohexanone was treated as a standard substance for the correction of outflow time.

At this time, the peak top of the main peak of cyclohexanone is adjusted so that the retention time is from 27 minutes to 31 minutes, and the peak end is 2 minutes from the peak start of the main peak of cyclohexanone, and the peak of cyclohexanone is excluded. Each component (a) to 19 minutes, and the peak start to peak end of the main peak excluding the cyclohexanone peak is 2 minutes to 4 minutes and 30 seconds. (C);
(A) Component represented by the main peak;
(B) A component represented by a GPC peak detected at a time later than the minimum value on the time side where the retention time at the main peak is late;
(C) A component represented by a GPC peak detected earlier than the minimum value on the time side where the retention time at the main peak is earlier;
Was detected.

[Measuring method of filler particle size]
The BET-equivalent particle size was applied to the filler having a particle size of less than 0.4 μm.
For fillers with a particle size of 0.4 μm or more, a laser diffraction type particle size distribution measuring device (manufactured by Malvern, trade name; Master Sizer 3000) is used, water is used as a dispersion medium, and the particle refractive index is 1.54. The particle size was measured by the laser diffraction / scattering type measurement method under the above conditions. The value at which the cumulative value in the frequency distribution curve obtained by the volume-based particle size distribution measurement by the laser diffraction method is 50% was defined as the average particle diameter _D50 .

[Measurement of storage elastic modulus]
The measurement was performed using a dynamic viscoelasticity measuring device (DMA: manufactured by TA Instruments, trade name: RSA-G2).

[Evaluation of dielectric properties]
Temperature; 23 ° C., Humidity; 50% of polyimide film (cured polyimide film) using a vector network analyzer (manufactured by Agent, trade name; vector network analyzer E8633C) and a split post dielectric resonator (SPDR resonator). After standing for 24 hours under the condition of RH, the relative permittivity (ε) and the dielectric constant tangent (Tanδ) at a frequency of 10 GHz were measured.

[Measurement of viscosity]
The viscosity (250 ° C.) of the polyamic acid solution was measured using an E-type viscometer (manufactured by Brookfield, trade name; DV-II + Pro). The rotation speed was set so that the torque was 10% to 90%, and 2 minutes after the start of the measurement, the value when the viscosity became stable was read.

[Glass transition temperature (Tg)]
1) Adhesive sheet The adhesive sheet pressed under the conditions of temperature; 160 ° C., pressure; 3.5 MPa, time; 60 minutes was cut into a test piece having a size of 5 mm × 20 mm, and a dynamic viscoelastic modulus measuring device (DMA: tee) was cut out. -Measurement was performed from 30 ° C to 200 ° C at a temperature rise rate of 4 ° C / min and a frequency of 11 Hz using A Instrument Co., Ltd., trade name; RSA-G2), and the elastic modulus change (tan δ) was maximized. The temperature was defined as the glass transition temperature.
2) Polyimide layer on a copper-clad laminate A polyimide film (10 mm × 22.6 mm) obtained by removing copper foil by etching is heated from 30 ° C to 450 ° C by a dynamic viscoelasticity measuring device DMA at a heating rate of 4 ° C. Dynamic viscoelasticity was measured at a frequency of / min and a frequency of 11 Hz, and the glass transition temperature Tg (tan δ maximum value) was determined.

[Tension modulus and maximum elongation]
Using a tension tester (Tensilon manufactured by Orientech), a test piece (width; 12.7 mm, length; 127 mm) was subjected to a tensile test at 50 mm / min to determine the tensile elastic modulus and maximum elongation at 25 ° C.

[Adhesive sheet solder heat resistance test]
1) Solder heat resistance test (drying)
Etching and removing one of the copper foils of the double-sided copper-clad laminate (manufactured by Nittetsu Chemical & Materials Co., Ltd., trade name; Espanex MB12-25-12UEG), and the other copper foil surface and the adhesive sheet with copper foil. They were laminated in a sandwiched manner and pressed under the conditions of temperature; 160 ° C., pressure; 3.5 MPa, time; 60 minutes. After drying this test piece with copper foil at 135 ° C./60 minutes, it was immersed in a solder bath set at each evaluation temperature from 260 ° C. to 300 ° C. in increments of 260 ° C. for 10 seconds, and the adhesive state was observed. It was confirmed that there were no problems such as foaming, blistering, and peeling. As a judgment, if no defect was found at 280 ° C, it was evaluated as 〇 (good), and if a defect was observed, it was evaluated as × (defective).
2) Solder heat resistance test (moisture absorption)
The copper foil on one side of the double-sided copper-clad laminate (manufactured by Nittetsu Chemical & Materials Co., Ltd., trade name; Espanex MB12-25-12UEG) is removed by etching, and the other copper foil surface and the adhesive sheet are removed with copper foil. They were laminated in a sandwiched manner and pressed under the conditions of temperature; 160 ° C., pressure; 3.5 MPa, time; 60 minutes. The test piece with the copper foil was left at 40 ° C. and relative humidity; 90% RH for 72 hours, and then immersed in a solder bath set at each evaluation temperature from 240 ° C. to 10 ° C. in increments of 10 ° C. for 10 seconds. By observing the adhesive state, it was confirmed whether there were any problems such as foaming, blistering, and peeling. As a judgment, if no defect was found at 260 ° C., it was evaluated as 〇 (good), and if a defect was found, it was evaluated as × (defective).

[Solder heat resistance test of polyimide layer on copper-clad laminate]
Etching so that the copper foil layer of the copper-clad laminate produced in each example and comparative example remains 20 mmΦ, and the width; 4 cm × length; 4 cm is cut so that the 20 mmΦ copper foil layer is in the center, and the measurement sample is taken. Was prepared. It was immersed in a solder bath set at each evaluation temperature from 220 ° C. to 370 ° C. in increments of 10 ° C. for 60 seconds, and the temperature at which swelling, peeling and melting did not occur was evaluated.

[Measurement of peel strength]
1) Peel strength of adhesive sheet Double-sided copper-clad laminate (manufactured by Nittetsu Chemical & Materials Co., Ltd., trade name; Espanex MB12-25-12UEG) is cut into a width of 50 mm, a length of 100 mm, and then copper on one side. An adhesive sheet is placed on the copper foil side of the sample from which the foil has been removed by etching, and a polyimide film (manufactured by Toray DuPont Co., Ltd., trade name; Kapton 50EN-S) is laminated on the adhesive sheet, and the temperature is 160. A laminate was prepared by pressing under the conditions of ° C., pressure; 3.5 MPa, time: 60 minutes. This laminate was cut out to a width of 5 mm and used as a test piece, and it was adhered when the test piece was pulled in the 180 ° direction at a speed of 50 mm / min using a tensile tester (manufactured by Toyo Seiki Seisakusho, trade name; Strograph VE). The peel strength between the agent layer and the copper foil was measured and used as the peel strength.
2) Copper foil peeling strength (peeling strength) in copper-clad laminates
After processing the copper foil layer of the copper-clad laminate to a width of 1.0 mm, the copper foil layer was cut into a width of 8 cm × a length of 4 cm to prepare a measurement sample. Using a Tensilon tester (manufactured by Toyo Seiki Seisakusho, trade name; Strograph VE-1D), one side of the measurement sample is fixed to an aluminum plate with double-sided tape, and the other side is 50 mm / min in the 180 ° direction. At a speed, the central strength when peeled by 10 mm was determined. From a practical point of view, a peel strength of 1.0 kN / m or more was evaluated as good “◯”, and a peel strength of less than 1.0 kN / m was evaluated as defective “x”.

[Evaluation method of film retention]
The adhesive sheet was cut into test pieces having a width of 20 mm and a length of 20 mm, bent so as to have creases along the diagonal line, and then opened to observe the state of the film. At this time, those with no cracks in the test piece even after making creases and opening were rated as "good", and those with some cracks were rated as "impossible".

[Measurement of surface roughness of copper foil]
The sample was cut into a size of about 10 mm square, fixed to the sample table with double-sided tape, irradiated with soft X-rays to remove static electricity on the surface of the copper foil, and then the surface roughness was measured. Arithmetic mean roughness (Ra) and ten-point average roughness Rz of the copper foil surface using a scanning probe microscope (AFM, manufactured by Bruker AXS, trade name: Dimension Icon type SPM) under the following measurement conditions. (RzJis) was measured. The measurement conditions are as follows.
Measurement mode; Tapping mode Measurement area; 1 μm × 1 μm
Scan speed; 1Hz
Probe; Bruker, RTESS-300

The abbreviations used in this example indicate the following compounds.
BTDA: 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride PMDA: pyromellitic acid dianhydride BPDA: 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride DDA: Crowder Japan Manufactured by Co., Ltd., trade name; PRIAMINE 1075 distilled and purified (a component; 99.2%, b component: 0%, c component; 0.8%, amine value: 210 mgKOH / g)
BAPP: 2,2 bis- [4- (4-aminophenoxy) phenyl] Propane DAPE: 4,4'-diaminodiphenyl ether m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl TPE-R: 1,3-Bis (4-aminophenoxy) Benzene N-12: Dodecanedioic acid dihydrazide NMP: N-methyl-2-pyrrolidone DMAc: N, N-dimethylacetamide filler 1: Ube Materials Co., Ltd., trade name; high Purity ultrafine powder magnesia 500A (magnesium oxide, primary particles; single crystal, cubic shape, purity; magnesium oxide> 99.98%, specific gravity; 3.58, BET equivalent particle size; 52 nm, thermal expansion coefficient; 13 ppm / K)
Filler 2: Made by Ube Material Industries, Ltd., trade name; high-purity ultrafine powder Magnesia 2000A (magnesium oxide, primary particles; single crystal, cubic shape, purity; magnesium oxide> 99.98%, specific gravity; 3.58, BET-equivalent particles Diameter: 200 nm, coefficient of thermal expansion: 13 ppm / K)
Filler 3: Made by Ube Material Industries, Ltd., trade name; RF-10CS (magnesium oxide, purity; magnesium oxide 99.34%, specific gravity; 3.58, average particle size D ₅₀ ; 5.8 μm, minimum particle size; 4 μm, Maximum particle size; ≤45 μm)
Filler 4: Made by Ube Material Industries, Ltd., trade name; RF-10CS-SC (magnesium oxide, purity; magnesium oxide 98.98%, specific gravity; 3.58, average particle size D ₅₀ ; 6.1 μm, minimum particle size; 4 μm, maximum particle size; ≦ 45 μm)
Filler 5: manufactured by Sumitomo Chemical Co., Ltd., trade name; Advanced Alumina AA-04 (alumina, purity; aluminum oxide ≧ 99.99%, specific gravity; 3.97, average particle size D ₅₀ ; 0.5 μm)
Filler 6: Made by HUBER, trade name; KEMGARD1100 (zinc molybdate magnesium silicate compound, specific gravity; 2.8, average particle size D ₅₀ ; 2.0 μm, maximum particle size; <10 μm)
Filler 7: manufactured by Admatex, trade name; SE4050 (silica, spherical, average particle size D ₅₀ ; 400 nm, coefficient of thermal expansion; 0.2 ppm / K)
In the above DDA, "%" of the a component, the b component and the c component means the area percentage of the chromatogram in the GPC measurement. The molecular weight of DDA was calculated by the following formula.
Molecular weight = 56.1 × 2 × 1000 / amine value

(Synthesis Example 1)
A 1000 ml separable flask is charged with 55.51 g of BTDA (0.1721 mol), 94.49 g of DDA (0.1735 mol), 210 g of NMP and 140 g of xylene and mixed well at 40 ° C. for 1 hour. Then, a polyamic acid solution was prepared. This polyamic acid solution was heated to 190 ° C., heated for 10 hours, stirred, and 125 g of xylene was added to complete imidization of polyimide solution 1 (solid content; 31% by weight, weight average molecular weight; 80,900, heat). Plastic polyimide) was prepared.

[Example 1]
1.12 g of N-12 and 7.8 g of filler 2 are mixed with 100 g of the polyimide solution 1 prepared in Synthesis Example 1, xylene is added so that the solid content becomes 31% by weight, diluted, and stirred. Therefore, the polyimide varnish 1a was prepared.

[Examples 2 to 7]
Polyimide varnishes 2a to 7a were prepared in the same manner as in Example 1 except that the filler and the blending amount thereof were changed as shown in Table 1.

Comparative Examples 1 and 2
Polyimide varnishes 8a and 9a were prepared in the same manner as in Example 1 except that the filler and the blending amount thereof were changed as shown in Table 1.

[Example 8]
The polyimide varnish 1a prepared in Example 1 is applied to one side of a PET film that has been mold-released, dried at 100 ° C. for 5 minutes, dried at 120 ° C. for 10 minutes, and peeled off to obtain an adhesive sheet 1b. (Thickness; 25 μm) was prepared.
The various evaluation results of the adhesive sheet 1b are as follows.
Relative permittivity; 3.1, dielectric loss tangent; 0.0022, tensile modulus; 0.6 GPa, maximum elongation; 125%, Tg; 42 ° C., film retention; good, solder heat resistance test (dry); 〇, Handa heat resistance test (moisture absorption); 〇, peel strength; 1.7 kN / m

[Example 9]
An adhesive sheet 2b was prepared in the same manner as in Example 8 using the polyimide varnish 2a.
The various evaluation results of the adhesive sheet 2b are as follows.
Relative permittivity; 3.1, dielectric loss tangent; 0.0020, tensile modulus; 0.7 GPa, maximum elongation; 124%, Tg; 43 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); 〇, peel strength; 1.5 kN / m

[Example 10]
An adhesive sheet 3b was prepared in the same manner as in Example 8 using the polyimide varnish 3a.
The various evaluation results of the adhesive sheet 3b are as follows.
Relative permittivity; 3.3, dielectric loss tangent; 0.0019, tensile modulus; 0.8 GPa, maximum elongation; 99%, Tg; 44 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); 〇, peel strength; 2.0 kN / m

[Example 11]
An adhesive sheet 4b was prepared in the same manner as in Example 8 using the polyimide varnish 4a.
The various evaluation results of the adhesive sheet 4b are as follows.
Relative permittivity; 2.9, dielectric loss tangent; 0.0020, tensile modulus; 0.7 GPa, maximum elongation; 133%, Tg; 43 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); 〇, peel strength; 2.2 kN / m

[Example 12]
An adhesive sheet 5b was prepared in the same manner as in Example 8 using the polyimide varnish 5a.
The various evaluation results of the adhesive sheet 5b are as follows.
Relative permittivity; 2.9, dielectric loss tangent; 0.0020, tensile modulus; 0.7 GPa, maximum elongation; 155%, Tg; 43 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); 〇, peel strength; 2.2 kN / m

[Example 13]
An adhesive sheet 6b was prepared in the same manner as in Example 8 using the polyimide varnish 6a.
The various evaluation results of the adhesive sheet 6b are as follows.
Relative permittivity; 2.7, dielectric loss tangent; 0.0022, tensile modulus; 0.7 GPa, maximum elongation; 130%, Tg; 42 ° C., film retention; good, solder heat resistance test (dry); 〇, Handa heat resistance test (moisture absorption); 〇, peel strength; 1.3 kN / m

[Example 14]
Using the polyimide varnish 7a, the adhesive sheet 7b was prepared in the same manner as in Example 8.
The various evaluation results of the adhesive sheet 7b are as follows.
Relative permittivity; 2.7, dielectric loss tangent; 0.0022, tensile modulus; 0.7 GPa, maximum elongation; 132%, Tg; 42 ° C., film retention; good, solder heat resistance test (dry); 〇, Handa heat resistance test (moisture absorption); 〇, peel strength; 1.4 kN / m

Comparative Example 3
An adhesive sheet 8b was prepared in the same manner as in Example 8 using the polyimide varnish 8a.
The various evaluation results of the adhesive sheet 8b are as follows.
Relative permittivity; 3.1, dielectric loss tangent; 0.0023, tensile modulus; 0.7 GPa, maximum elongation; 142%, Tg; 43 ° C., film retention; good, solder heat resistance test (dry); ×, Handa heat resistance test (moisture absorption); ×, peel strength; 0.5 kN / m

Comparative Example 4
An adhesive sheet 9b was prepared in the same manner as in Example 8 using the polyimide varnish 9a.
The various evaluation results of the adhesive sheet 9b are as follows.
Relative permittivity; 2.8, dielectric loss tangent; 0.0026, tensile modulus; 1.1 GPa, maximum elongation; 103%, Tg; 44 ° C., film retention; good, solder heat resistance test (dry); 〇, Solder heat resistance test (moisture absorption); 〇, peel strength; 1.4 kN / m

The above results are summarized in Table 2.

From Table 2, as compared with the adhesive sheets 8b and 9b of Comparative Examples 3 and 4, the adhesive sheets 1b to 7b of Examples 8 to 14 have improved solder heat resistance and peel strength without deteriorating the dielectric properties. It was confirmed that it was done. From these results, the adhesive sheet as the resin film according to the present embodiment can be expected to reduce the transmission loss in the high frequency band of, for example, about 10 to 20 GHz, and while maintaining flexibility and film retention. It was confirmed that it has excellent solder heat resistance and peel strength.

Synthesis Examples 2-4
In order to synthesize the polyamic acid solutions 2 to 4, the solvent DMAc was added to a 1000 ml separable flask under a nitrogen stream so as to have the solid content concentration shown in Table 3, and the diamine components shown in Table 3 were added. And the acid anhydride component was heated at 45 ° C. for 2 hours with stirring to dissolve it. Then, the solution was stirred at room temperature for 3 hours to carry out a polymerization reaction to prepare viscous solutions 2 to 4 of polyamic acid. In Table 3, the glass transition temperature (Tg) measured by forming a film of the polyimide obtained by imidizing the polyamic acid obtained in Synthesis Examples 2 to 4 is also shown.

Synthesis example 5
2.160 g of the filler 2 was added to 400 g of the polyamic acid solution 2 prepared in Synthesis Example 2 and stirred to prepare a polyamic acid solution 5 (Tg: 330 ° C.).

Synthesis example 6
2.160 g of the filler 2 was added to 400 g of the polyamic acid solution 3 prepared in Synthesis Example 3 and stirred to prepare a polyamic acid solution 6 (Tg: 280 ° C.).

Synthesis example 7
2.160 g of the filler 7 was added to 400 g of the polyamic acid solution 3 prepared in Synthesis Example 3 and stirred to prepare a polyamic acid solution 7 (Tg: 280 ° C.).

[Example 15]
The polyamic acid solution 5 was uniformly applied to the surface of a long electrolytic copper foil (Rz; 0.8 μm, Ra; 0.2 μm) so that the cured thickness would be 12 μm, and then heated and dried at 120 ° C. The solvent was removed. After that, a stepwise heat treatment was performed from 120 ° C. to 360 ° C. to complete imidization, and a single-sided copper-clad laminate 1 was prepared.

[Example 16]
A single-sided copper-clad laminate 2 was prepared in the same manner as in Example 15 except that the polyamic acid solution 6 was used instead of the polyamic acid solution 5.

[Example 17]
The polyamic acid solution 5 was uniformly applied to the surface of a long electrolytic copper foil (Rz; 0.8 μm, Ra; 0.2 μm) so that the cured thickness was 2 μm, and then heated and dried at 120 ° C. The solvent was removed. Next, the polyamic acid solution 4 was uniformly applied onto the polyamic acid solution 4 so as to have a thickness of 21 μm after curing, and then heated and dried at 120 ° C. to remove the solvent. Further, the polyamic acid solution 5 was uniformly applied thereto so as to have a thickness of 2 μm after curing, and then heated and dried at 120 ° C. to remove the solvent. After forming the three polyamic acid layers in this way, a stepwise heat treatment was performed from 120 ° C. to 360 ° C. to complete imidization, and a single-sided copper-clad laminate 3 was prepared.

[Example 18]
A single-sided copper-clad laminate 4 was prepared in the same manner as in Example 17 except that the polyamic acid solution 6 was used instead of the polyamic acid solution 5.

Comparative Example 5
A single-sided copper-clad laminate 5 was prepared in the same manner as in Example 15 except that the polyamic acid solution 3 was used instead of the polyamic acid solution 5.

Comparative Example 6
A single-sided copper-clad laminate 6 was prepared in the same manner as in Example 15 except that the polyamic acid solution 7 was used instead of the polyamic acid solution 5.

Comparative Example 7
A single-sided copper-clad laminate 7 was prepared in the same manner as in Example 17 except that the polyamic acid solution 3 was used instead of the polyamic acid solution 5.

The evaluation results of Examples 15 to 18 and Comparative Examples 5 to 7 are shown in Tables 4 and 5 below.

From Tables 4 and 5, by blending the magnesium oxide filler in the polyimide layer in contact with the copper foil, the solder heat resistance and the solder heat resistance are higher than those of Comparative Examples 5 and 7 in which the filler is not blended and Comparative Example 6 in which the spherical silica filler is blended. It has been shown that both peel strengths can be improved.

[Test Example 1]
Measurement of weight loss rate:
Thermogravimetric analysis was performed to investigate the state of magnesium hydroxide production caused by magnesium oxide hydration. For the magnesium oxide samples (1) to (5) shown below, a thermogravimetric analyzer (TG: Hitachi High-Tech Science Co., Ltd., trade name: TG / DTA7220) was used in a nitrogen atmosphere at 10 ° C./min. The weight loss at 350 ° C. when heated from 30 ° C. to 450 ° C. at the heating rate was measured, and the weight loss rate associated with the thermal decomposition of magnesium hydroxide was determined.

As the samples (1) to (5), the above-mentioned "filler 2" was used.
Sample (1): Immediately after opening Sample (2): After opening, put in a reagent bottle and store in a laboratory at room temperature and humidity for one year (the lid was opened and closed each time it was used).
Sample (3): After opening, exposed in an environment of 40 ° C. and 90% humidity for 24 hours Sample (4): After opening, exposed in an environment of 40 ° C. and 90% humidity for 48 hours (4) 5): After opening, exposed to an environment with a temperature of 40 ° C and a humidity of 90% for 72 hours.

The results of thermogravimetric analysis measurement are shown in FIG. From FIG. 1, the samples (1) to (5) have weight loss rates of 0.36%, 1.46%, 0.85%, 1.59%, and 1.85% at 350 ° C., respectively. However, the weight loss rate of sample (1) was the smallest, and the weight loss rate increased in the order of sample (3), sample (2), sample (4), and sample (5). You can see that. From this result, it was confirmed that magnesium oxide was hydrated and the production of magnesium hydroxide proceeded depending on the environmental humidity.

[Test Example 2]
The sample (1) used in Test Example 1 was subjected to X-ray diffraction measurement by a wide-angle X-ray diffraction method using an X-ray diffractometer [SmartLab (rotational vs. cathode) manufactured by Rigaku Co., Ltd.] under the following conditions. ..
X-ray source: MoKα ray (using Kβ filter)
Output: 60kV, 150mA
Slit system: CBO condensing mirror detector: Hyper-3000 (1D mode)
Scan method: 2θ / θ continuous scan Measurement range (2θ): 5 to 50 °
Step width (2θ): 0.01 °
Scan speed: 4 ° / min

The results of the X-ray diffraction measurement are shown in FIG. 2 (a), and the peak position of Mg (OH) ₂ in the X-ray diffraction measurement is shown in FIG. 2 (b) for reference. Further, when the ratio of magnesium hydroxide was calculated by Rietveld analysis based on the result of FIG. 2 (a), MgO was 100% by weight and Mg (OH) ₂ was 0% by weight.

From the above, it was confirmed that in the sample (1), the peak derived from magnesium oxide was detected in the X-ray diffraction measurement, but the peak derived from magnesium hydroxide was not detected. Specifically, peaks derived from magnesium oxide were detected at positions where 2θ was 16.8 °, 19.4 °, 27.6 °, 32.5 ° and 34.0 °, but 2θ was 8. No peaks derived from magnesium hydroxide were detected at 5 °, 17.3 °, 22.8 ° and 26.1 °, and sample (1) was substantially free of magnesium hydroxide. confirmed.

As described above, as shown in each example, by adding the magnesium oxide filler to the polyimide, a clear improvement in solder heat resistance and an improvement in peel strength were observed without deteriorating the dielectric properties.
Furthermore, it was also confirmed that the adhesive sheet obtained in each example maintained the shape as a film at a blending amount of the magnesium oxide filler within the practical range.

From the above results, it was confirmed that the resin film according to the present embodiment is suitably used as a material for a circuit board such as a high frequency FPC.

Although the embodiments of the present invention have been described in detail for the purpose of illustration, the present invention is not limited to the above embodiments and can be modified in various ways.

Claims (18)

The following components (A) and (B);
(A) Polyimide obtained by reacting a tetracarboxylic acid anhydride component with a diamine component, and (B) a magnesium oxide filler having an average particle size in the range of 30 nm to 10 μm.
A resin composition containing 1 to 50% by weight of the component (B) with respect to the total amount of the component (A) and the component (B). The resin composition according to claim 1, wherein the magnesium oxide filler contains 95.0% by weight or more of magnesium oxide. The resin according to claim 1, wherein the magnesium oxide filler has a weight loss rate of 2% or less at 350 ° C. when heated from 30 ° C. to 450 ° C. at a heating rate of 10 ° C. per minute in thermogravimetric analysis measurement. Composition. The resin composition according to claim 1, wherein the magnesium oxide filler does not detect a peak derived from magnesium hydroxide in X-ray diffraction measurement. The first aspect of claim 1, wherein the diamine component contains 40 mol% or more of an aliphatic diamine with respect to the total diamine component, and the average particle size of the magnesium oxide filler is in the range of 200 nm to 10 μm. Resin composition. The resin according to claim 5, wherein the aliphatic diamine is a dimerdiamine composition containing a dimerdiamine as a main component, wherein the two terminal carboxylic acid groups of the dimer acid are replaced with a primary aminomethyl group or an amino group. Composition. The resin composition according to claim 1, further comprising an amino compound having at least two primary amino groups as functional groups. A resin film containing a filler-containing thermoplastic resin layer.
The filler-containing thermoplastic resin layer contains the following components (A) and (B);
(A) Polyimide obtained by reacting a tetracarboxylic acid anhydride component with a diamine component, and (B) a magnesium oxide filler having an average particle size in the range of 30 nm to 10 μm.
The resin film is characterized by containing the above component (A) and the content of the component (B) in the range of 1 to 50% by weight with respect to the total amount of the component (A) and the component (B). The resin film according to claim 8, wherein the magnesium oxide filler contains 95.0% by weight or more of magnesium oxide. The resin according to claim 8, wherein the magnesium oxide filler has a weight loss rate of 2% or less at 350 ° C. when heated from 30 ° C. to 450 ° C. at a heating rate of 10 ° C. per minute in thermogravimetric analysis measurement. the film. The resin film according to claim 8, wherein the magnesium oxide filler does not detect a peak derived from magnesium hydroxide in X-ray diffraction measurement. The eighth aspect of claim 8, wherein the diamine component contains 40 mol% or more of an aliphatic diamine with respect to the total diamine component, and the average particle size of the magnesium oxide filler is in the range of 200 nm to 10 μm. Resin film. The filler-containing thermoplastic resin layer has a dielectric loss tangent (Tanδ) at 10 GHz measured by a split post dielectric resonator (SPDR) after humidity control for 24 hours under a constant temperature and humidity condition of 23 ° C. and 50% RH. The resin film according to claim 8, which is 0.0022 or less. A laminate having a substrate and an adhesive layer laminated on at least one surface of the substrate.
A laminate characterized in that the adhesive layer is made of the resin film according to claim 8. A coverlay film having a coverlay film material layer and an adhesive layer laminated on the coverlay film material layer.
A coverlay film, wherein the adhesive layer is made of the resin film according to claim 8. A copper foil with a resin in which an adhesive layer and a copper foil are laminated.
A copper foil with a resin, wherein the adhesive layer is made of the resin film according to claim 8. A metal-clad laminate having an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer.
A metal-clad laminate characterized in that at least one of the insulating resin layers is made of the resin film according to claim 8. A circuit board obtained by wiring processing the metal layer of the metal-clad laminate according to claim 17.

Images