KR20210122145A - Resin composition, method for producing same, resin film and metal clad laminate - Google Patents

Abstract

The present invention relates to a resin film including polyimide containing a filler for a liquid crystal polymer dispersed therein and having excellent dielectric properties compatible with dimensional stability. The present invention provides a resin composition including: (A) a polyamic acid formed by reacting a tetracarboxylic anhydride ingredient with a diamine ingredient; and (B) a filler having shape anisotropy including a liquid crystal polymer, wherein the filler of ingredient (B) preferably has a ratio (L/D) of average long axis diameter (L) to average short axis diameter (D) of 3-200, an average long axis diameter (L) of 50-3000 micrometers, and an average short axis diameter (D) of 1-50 micrometers. The present invention also provides a resin film obtained from the resin composition, and the resin film includes a polyimide layer having shape anisotropy and containing polyimide and a liquid crystal polymer dispersed in the polyimide.

Description

A resin composition, its manufacturing method, a resin film, and a metal-clad laminate TECHNICAL FIELD

The present invention relates to, for example, a resin film and a metal-clad laminate useful as a circuit board material, a resin composition used therein, and a manufacturing method thereof.

Flexible Printed Circuit Board (FPC) is three-dimensional and high-density mounting even in a limited space, so its use has been expanded to parts such as wiring of moving parts of electronic devices, cables, connectors, etc., and in many fields installed in the device of Concomitantly, the environment in which the FPC is used is diversified, and the performance required is also being advanced.

For example, in information processing and information communication, measures are taken to increase the transmission frequency in order to transmit and process large-capacity information, and a reduction in transmission loss by improvement of the dielectric properties of the insulating resin layer of the circuit board is required. As a technique of improving the dielectric properties in the insulating resin layer of a circuit board, it is proposed to mix|blend liquid crystalline polymer particle with a thermoplastic resin or a thermosetting resin (patent document 1). However, patent document 1 does not have an Example other than the epoxy resin which is a thermosetting resin, and detailed examination is not made about a thermoplastic resin.

Moreover, high dimensional stability is also calculated|required by the insulating resin layer of a circuit board by progress of miniaturization accompanying high-density packaging. As a technique for improving the dimensional stability in the insulating resin layer of a circuit board, mix|blending an organic filler or an inorganic filler is proposed (patent documents 2 - 4).

Japanese Patent Publication No. 6295013 Japanese Patent Laid-Open No. 11-273456 Japanese Patent Laid-Open No. 10-338809 Japanese Patent Laid-Open No. 2006-321853

Polyimide is a resin having excellent properties such as heat resistance and chemical resistance, and is widely used as a material for insulating resin layers of circuit boards. On the other hand, liquid crystal polymers are also used as circuit board materials, and are excellent in dielectric properties. From this point of view, it is conceivable to improve the dielectric properties of the polyimide film by blending the liquid crystal polymer as a filler in the polyimide. However, since the liquid crystal polymer has a large coefficient of thermal expansion (CTE), there is concern that the dimensional stability of the insulating resin layer is impaired.

Accordingly, an object of the present invention is to provide a resin film in which a liquid crystal polymer filler is dispersed in polyimide, and in which excellent dielectric properties and dimensional stability are compatible.

The resin composition of the present invention comprises the following components (A) and (B);

(A) the polyamic acid formed by making a tetracarboxylic-acid anhydride component and a diamine component react;

and

(B) Filler with shape anisotropy containing liquid crystal polymer

contains

In the resin composition of the present invention, the ratio (L/D) of the average major axis diameter (L) to the average minor axis diameter (D) of the filler of the component (B) may be in the range of 3 to 200.

As for the resin composition of this invention, the average major axis diameter (L) of the filler of the said (B) component may exist in the range of 50-3000 micrometers, and the average minor axis diameter (D) may exist in the range of 1-50 micrometers.

In the resin composition of this invention, content of the filler of the said (B) component may exist in the range of 1-70 volume% with respect to the total amount of the said (A) component and the said (B) component.

In the resin composition of the present invention, the liquid crystal polymer may have a melting point of 280°C or higher.

In the resin composition of the present invention, the liquid crystal polymer may have a polyester structure.

20 GPa or more may be sufficient as the resin composition of this invention in the long-axis direction of the filler of the said (B) component.

In the resin composition of the present invention, the ratio of the tensile modulus of elasticity in the major axis direction of the filler of the component (B) to the tensile modulus of elasticity of the polyimide obtained by curing the polyamic acid of the component (A) may be 1 or more.

The ratio of the true specific gravity of the filler of the said (B) component with respect to the true specific gravity of the polyimide obtained by hardening the polyamic acid of the said (A) component in the resin composition of this invention may exist in the range of 0.5-2.0.

In the resin composition of the present invention, the relative dielectric constant at 1 GHz of the liquid crystal polymer of the component (B) may be in the range of 2.0 to 3.5, and the dielectric loss tangent may be less than 0.003.

The method for producing the resin composition of the present invention is a method for producing any of the above resin compositions, and before the reaction of synthesizing the polyamic acid by reacting the tetracarboxylic anhydride component with the diamine component is completed, (B ) is characterized by adding a filler having shape anisotropy containing a liquid crystal polymer as a component.

In the method for producing the resin composition of the present invention, before the viscosity of the reaction solution of the tetracarboxylic anhydride component and the diamine component reaches 1500 cps, a filler having shape anisotropy containing the liquid crystal polymer of the component (B) is added. and may be mixed.

The resin film of the present invention is a resin film comprising a polyimide layer,

The said polyimide layer contains a polyimide and the filler which has shape anisotropy containing the liquid crystal polymer disperse|distributed in the said polyimide, It is characterized by the above-mentioned.

As for the resin film of this invention, 30 ppm/K or less may be sufficient as the thermal expansion coefficient of the said polyimide layer.

As for the resin film of this invention, the dielectric constant in 10 GHz of the said polyimide layer may exist in the range of 2.0-3.8, and the dielectric loss tangent may be 0.004 or less.

In the resin film of this invention, content of the filler which has shape anisotropy containing the liquid crystal polymer with respect to the total amount of the resin component in the said polyimide layer may exist in the range of 1-70 volume%.

In the resin film of the present invention, the longitudinal direction of the liquid crystal polymer may be oriented in the polyimide layer.

The metal-clad laminate of the present invention is a metal-clad laminate comprising an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer,

At least one layer of the insulating resin layer is any of the above resin films.

ADVANTAGE OF THE INVENTION According to this invention, the filler of a liquid crystal polymer is disperse|distributed in polyimide, and the resin film in which the outstanding dielectric property and dimensional stability are compatible is provided. The resin film of this invention can be used suitably as circuit board materials, such as FPC in various electronic devices, from the point which the loss in high frequency signal transmission is reduced and dimensional stability can also be maintained.

BRIEF DESCRIPTION OF THE DRAWINGS It is a photograph of the external appearance of the resin layer of the copper clad laminated board produced in Example 7. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described.

[resin composition]

The resin composition of this embodiment, the following components (A) and (B),

(A) the polyamic acid formed by making a tetracarboxylic-acid anhydride component and a diamine component react;

and

(B) Filler with shape anisotropy containing liquid crystal polymer (hereinafter, may be referred to as "LCP filler")

contains

[Component A: polyamic acid]

The polyamic acid of the component A is a precursor of a polyimide, and is obtained by making a tetracarboxylic-acid anhydride component and a diamine component react. A polyimide is a polymer which has an imide group represented by the following general formula (1). Moreover, when it has an amide group or an ether bond, it may be called polyamideimide or polyetherimide, but in this specification, these are generically described as polyimide. The polyimide can be produced by a known method in which a diamine component and an acid dianhydride component are used in substantially equimolar amounts and polymerized in an organic polar solvent. In this case, in order to make a viscosity into a desired range, you may adjust the molar ratio of the acid dianhydride component with respect to a diamine component, and it is preferable to make the range into the range of the molar ratio of 0.98 to 1.03, for example.

In the general formula (1), Ar ₁ represents a tetravalent group derived from an acid anhydride containing a tetracarboxylic dianhydride residue, R ₂ represents a divalent diamine residue derived from diamine, and n is an integer greater than or equal to 1 am.

As the acid dianhydride, for example, _{an aromatic tetracarboxylic dianhydride represented by O(OC) 2} -Ar ₁ -(CO) ₂ O is preferable, and giving the following aromatic acid anhydride residue as Ar ₁ is exemplified. do.

The acid dianhydride may be used alone or in combination of two or more. Among these, pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride It is preferable to use one selected from water (BTDA), 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA) and 4,4'-oxydiphthalic dianhydride (ODPA). .

As the diamine, for example a diamine to a diamine represented by H ₂ NR ₂ -NH ₂ are preferred, to give the diamine residue as R ₂ and the like.

Among these diamines, diaminodiphenyl ether (DAPE), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), paraphenylenediamine (p-PDA), 1,3-bis( 4-aminophenoxy)benzene (TPE-R), 1,3-bis (3-aminophenoxy) benzene (APB), 1,4-bis (4-aminophenoxy) benzene (TPE-Q), 2 ,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), and 2,2-bis(trifluoromethyl)benzidine (TFMB) are exemplified as suitable.

The synthesized polyamic acid is usually advantageously used as a reaction solvent solution, but it can be concentrated, diluted or replaced with another organic solvent as needed to form a resin composition. The method for imidating the polyamic acid is not particularly limited, and for example, a heat treatment such as heating in the above solvent at a temperature within the range of 80 to 400° C. over 1 to 24 hours is suitably employed.

[Component (B): LCP Filler]

The LCP filler comprises a liquid crystal polymer. Liquid crystal polymer has little frequency dependence of dielectric properties, has very excellent dielectric properties, and contributes to improvement of flame retardancy. When blending for the purpose of improving the dielectric properties of the resin film, the LCP filler is a single element, and the dielectric constant at 1 GHz is preferably in the range of 2.0 to 3.5, more preferably in the range of 2.7 to 3.2. and dielectric loss tangent is preferably less than 0.003, more preferably 0.002 or less.

The melting point of the liquid crystal polymer is sometimes referred to as a liquid crystal transition temperature or a liquid crystallization temperature, but preferably 280°C or higher. More preferably, it is 295 degreeC or more, More preferably, it is 310 degreeC or more.

When melting|fusing point is less than 280 degreeC, it may melt|dissolve in the manufacturing process of an electronic device etc., and there exists a possibility of causing the change of a characteristic.

Although it does not specifically limit as a liquid crystal polymer, For example, those having a polyester structure, such as well-known thermotropic liquid crystal polyester and polyesteramide derived from the compound classified into the following (1) to (4), and its derivative(s) desirable.

(1) aromatic or aliphatic dihydroxy compounds

(2) aromatic or aliphatic dicarboxylic acids

(3) aromatic hydroxycarboxylic acids

(4) aromatic diamines, aromatic hydroxylamines or aromatic aminocarboxylic acids

Representative examples of liquid crystal polymers obtained from these raw material compounds are copolymers having a combination of two or more selected from structural units represented by the following formulas (a) to (j), and the structural unit represented by formula (a) or formula (e) ) is preferable, and a copolymer including a structural unit represented by formula (a) and a structural unit represented by formula (e) is particularly preferable. In addition, as the number of aromatic rings in the liquid crystal polymer increases, the effect of improving dielectric properties and flame retardancy can be expected. it is preferable

LCP fillers have shape anisotropy. The shape anisotropy means that the ratio (L/D) of the average major axis diameter (L) to the average minor axis diameter (D) of the LCP filler is 3 or more, preferably within the range of 3 to 200. Here, assuming an imaginary cuboid circumscribed on the LCP pillar in a linearly stretched state, among the lengths of three perpendicular sides of the cuboid, the length of the shortest side is the minor axis diameter, and the length of the longest side is the major axis diameter. do.

The average major axis diameter (L) of the LCP filler is, for example, preferably in the range of 50 to 3000 µm, more preferably in the range of 100 to 1000 µm. Moreover, the inside of the range of 1-50 micrometers is preferable, for example, and, as for the average minor axis diameter (D) of an LCP filler, the inside of the range of 3-30 micrometers is more preferable. If the average major axis diameter (L) and the average minor axis diameter (D) are within the above ranges, the surface smoothness when a resin film is formed from the resin composition is not deteriorated, and a resin film with a good appearance can be obtained.

As a specific shape of an LCP filler, fibrous form (including needle form), plate form, etc. are mentioned, for example. As a fibrous form, milled fiber, a chopped fiber, a cut fiber etc. may be sufficient, for example. Examples of the plate shape include a disk shape, a flat shape, a flat shape, a flaky shape, a scale shape, and a rectangular shape. Further, the cross-sectional shape of the LCP filler is not limited to a circular shape, and may be a star shape, a flower shape, a cross shape, or a hollow shape. By changing the cross-sectional shape of the LCP filler, it is possible to control the surface area of the LCP filler to control adhesion to polyimide and to control the viscosity of the resin solution. From a viewpoint of the easiness of CTE control of a resin film, especially a short-fiber-form LCP filler is preferable.

It is preferable that the LCP filler is oriented so that the long axis direction thereof and the longitudinal direction of the liquid crystal polymer molecules substantially coincide. In order to orient the liquid crystal polymer molecules, it is important to undergo molding by a melting process and an extrusion process, and in particular, the maximum shear rate u at the time of extrusion obtained by the following formula is preferably 10 ³ sec ^-1 or more, more preferably is preferably set to 10 ⁴ sec ^-1 or more.

u=4Q/{π×(d/2) ³ }

[However, Q is the amount of polymer discharged per unit time (cm 3 /sec) that passes through the cross section of the extrusion outlet, and d represents the length (cm) of the shortest diameter of the cross section of the extrusion outlet, for example, a circular shape such as a nozzle or a pore on a tube. In the case of an extrusion outlet of

If it is such a maximum shear rate, the orientation of a liquid crystal molecule becomes sufficient, and controllability of CTE at the time of using it as an LCP filler becomes easy to be acquired.

Moreover, when the orientation of an LCP filler is inadequate, orientation can be controlled by extending|stretching after a casting|flow_spread or an extrusion process. In addition, by discharging the resin from the pores, the stretching step can be omitted, and for that purpose, the hole diameter (diameter) of the spinneret is preferably set to, for example, 1.0 mm or less, and more preferably 0.5 mm or less.

The LCP filler may be prepared by bundling the long fibers prepared by the above method, cutting them to a predetermined length, or pulverizing them. Moreover, the LCP filler can be manufactured also by grinding|pulverizing the molded object which improved the orientation degree of liquid crystal polymer molecules without setting it as a fibrous form.

Moreover, in order to reduce CTE of a resin film, it is preferable that it is 20 GPa or more, and, as for the tensile modulus in the long-axis direction of an LCP filler, it is more preferable to exist in the range of 40-200 GPa. In particular, it is preferable that the ratio ( _EL / _{EP ) of the tensile modulus E L} of the LCP filler in the major axis direction to _{the tensile modulus E P} of the polyimide obtained by curing the polyamic acid of component (A) is 1 or more. . When the relationship between _{the tensile modulus E P} of the polyimide used as the matrix in the resin film and the tensile modulus E _{L of the LCP filler is E L} ≥ _{E P} , the effect of CTE reduction becomes large.

In addition, the ratio (S _L / _{SP ) of the true specific gravity S L} of the LCP filler to the true specific gravity _SP of the polyimide obtained by curing the polyamic acid of the component (A) is, for example, within the range of 0.5 to 2.0. desirable. When the relationship between the true specific gravity _SP of the polyimide used as the matrix in the resin film and the true specific _{gravity S L} of the LCP filler is in the above range, the dispersibility of the LCP filler becomes good and the weight of the entire resin film is reduced. can do.

The LCP filler may be subjected to a surface modification treatment for the purpose of improving dispersibility and adhesion to polyimide. As a surface modification process, a plasma process, a coating process, etc. are mentioned, for example. In addition, the LCP pillar may have a core-sheath type structure. As the core-sheath structure, for example, it is preferable that the core portion is a liquid crystal polymer and the sheath portion is a resin having high adhesion to polyimide. As resin with high adhesiveness to polyimide, thermoplastic resins, such as a polyimide, polyamide, a perfluoroalkoxy fluororesin (PFA), and polyolefin, are suitable, for example.

The LCP filler can be used by appropriately selecting a commercially available product. For example, as a fibrous thing, Vectran (trade name) manufactured by Kuraray Corporation, Vectran (trade name) manufactured by Toray Corporation, Siberas (trade name) manufactured by Toray Corporation, Xexion (trade name) manufactured by KB Siren Corporation, etc. can be preferably used. Moreover, you may use together 2 or more types of different things as an LCP filler.

[solvent]

It is preferable that the resin composition further contains a solvent. Examples of the solvent include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2-butanone, dimethylsulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, dioxane, tetrahydrofuran, diglyme, triglyme, cresol, acetone, methyl Organic solvents, such as isobutyl ketone, are mentioned. Two or more of these solvents may be used in combination, and further, an aromatic hydrocarbon such as xylene or toluene may be used in combination. Although it does not restrict|limit especially as content of a solvent, It is preferable to adjust and use the usage-amount from which the solid content concentration in a resin composition will be about 5 to 50 weight%.

[Optional Ingredients]

In the resin composition, if necessary, as optional components, resin components other than polyamic acid, flame retardants, crosslinking agents, curing accelerators, chemical catalysts, organic fillers other than LCP fillers, inorganic fillers, plasticizers, coupling agents, pigments, etc. are appropriately blended can do.

[Furtherance]

Although content of the LCP filler of (B) component in a resin composition can be set suitably according to the purpose of use of a resin film, For example, 1-70 volume% with respect to the total amount of (A) component and (B) component. It is preferable to exist in the range, and it is more preferable to exist in the range of 5-65 volume%. If the blending amount of the LCP filler is less than the lower limit, the effect of improving dielectric properties and reducing CTE may not be sufficiently obtained. have.

Moreover, it is preferable to mix|blend the solvent in the quantity which can melt|dissolve the polyamic acid of (A) component and make it a solution state.

[Viscosity]

The viscosity of the resin composition is preferably within the range of 3000 cps to 100000 cps, for example, in the range of 3000 cps to 100000 cps, as a viscosity range that improves handleability when coating the resin composition and is easy to form a coating film of uniform thickness. It is more preferable to do When it is out of the said viscosity range, it will become easy to generate|occur|produce defects, such as thickness non-uniformity and a stripe, in a film at the time of the coating operation by a coater etc.

[Method for producing resin composition]

It is preferable that the resin composition adds the LCP filler of (B) component before the reaction which makes the tetracarboxylic-acid anhydride component which is a raw material of (A) component, and a diamine component react, and synthesize|combines a polyamic acid is complete. Even if the LCP filler is added after the synthesis reaction of the polyamic acid is completed, the aggregation of the LCP filler tends to occur, and the dispersing process after the aggregation is likely to be complicated. As a preferable criterion for the timing of adding the LCP filler, it is preferable to add and mix the LCP filler before, for example, the viscosity of the reaction solution of the tetracarboxylic anhydride component and the diamine component reaches 1500 cps. Even if the LCP filler is added after the viscosity of the reaction solution reaches 1500 cps, a uniform mixed state is not obtained.

In view of the above, it is more preferable to add the LCP filler to the tetracarboxylic anhydride component and/or the diamine component in the step before the tetracarboxylic anhydride component and the diamine component are reacted.

Specifically, after mixing the tetracarboxylic anhydride component, the diamine component, and the LCP filler at the same time, the tetracarboxylic acid anhydride component and the diamine component may be reacted to advance the synthesis reaction of the polyamic acid.

Moreover, you may start the synthesis reaction of a polyamic acid by adding and mixing a diamine component to the mixture which added the LCP filler to the tetracarboxylic-acid anhydride component.

Moreover, you may start the synthesis reaction of a polyamic acid by adding and mixing a tetracarboxylic-acid anhydride component to the mixture which added the LCP filler to the diamine component.

In either case, the tetracarboxylic-acid anhydride component used as a raw material, a diamine component, and LCP filler may inject|throw-in whole quantity at one time, and may divide into several times and may add them little by little. Moreover, you may use the solvent in which the LCP filler was disperse|distributed previously.

[Resin Film]

The resin film of this embodiment contains a polyimide and the polyimide layer (Hereinafter, it may describe as "LCP filler containing polyimide layer") containing the LCP filler disperse|distributed in the polyimide. The matrix resin of the LCP filler-containing polyimide layer is an imidized polyimide, in which the LCP filler is dispersed. A single layer may be sufficient as a resin film, and it may be comprised from multiple layers. That is, the LCP filler containing polyimide layer may be sufficient as the whole resin film, and resin layers other than an LCP filler containing polyimide layer may be included. However, it is preferable that an LCP filler containing polyimide layer is a main layer of a resin film. Here, a "main layer" means a layer which has a thickness exceeding 50% with respect to the total thickness of a resin film.

It is preferable that it is 30 ppm/K or less in consideration of dimensional stability as a circuit board material, and, as for the thermal expansion coefficient of the polyimide layer containing LCP filler in a resin film, it is more preferable to exist in the range of 1-25 ppm/K.

Further, the relative dielectric constant at 10 GHz of the LCP filler-containing polyimide layer is preferably in the range of 2.0 to 3.8, more preferably in the range of 2.5 to 3.5, in order to cope with high-frequency signal transmission. Further, the dielectric loss tangent at 10 GHz of the LCP filler-containing polyimide layer is preferably 0.004 or less, and more preferably 0.003 or less in order to cope with high-frequency signal transmission.

The content of the LCP filler with respect to the total amount of the resin component in the LCP filler-containing polyimide layer can be appropriately set depending on the intended use, but is preferably in the range of 1 to 70% by volume, for example, in the range of 5 to 65% by volume. Better be mine. If the content of the LCP filler is less than the lower limit, the effect of improving the dielectric properties and the effect of reducing the CTE may not be sufficiently obtained. . In addition, the volume ratio of the LCP filler in an LCP filler containing polyimide layer can also be computed from the imaging image by a three-dimensional transmission electron microscope (TEM), From the weight ratio obtained by the decomposition analysis by strong alkali dissolution or the thermal decomposition analysis method It can be obtained by conversion. In addition, it can also be calculated|required by calculation from the image volume ratio measurement by X-ray diffraction, and the area ratio of a cross-sectional SEM image.

In the LCP filler-containing polyimide layer, it is preferable that the longitudinal direction of the liquid crystal polymer molecules is oriented. In particular, it is preferable from the viewpoint of improving dimensional stability that the longitudinal direction (MD direction) of the LCP filler-containing polyimide layer and the longitudinal direction of the liquid crystal polymer molecules are substantially the same. For this purpose, as described above, it is preferable to orient the LCP filler so that the longitudinal direction of the LCP filler substantially coincides with the longitudinal direction of the liquid crystal polymer molecules.

<thickness>

Although the thickness of a resin film can be set suitably according to the purpose of use, for example, the inside of the range of 2-150 micrometers is preferable, and it is more preferable that it exists in the range of 10-120 micrometers. When the thickness of the resin film is not satisfied to 2 µm, there is a fear that problems such as wrinkles are generated during conveyance in the production of the resin film or the like, and on the other hand, when the thickness of the resin film exceeds 150 µm, the productivity of the resin film There is a risk of deterioration.

The resin film may be in the form of a film (sheet), and may be in a laminated state on an arbitrary base material, for example, a copper foil, a glass plate, a polyimide-based film, a polyamide-based film, or a polyester-based film.

[Method for producing resin film]

A resin film can be manufactured by heat-processing a resin composition and forming an LCP filler containing polyimide layer by imidating a polyamic acid. The method of heat-processing a resin composition to obtain an LCP filler containing polyimide layer is not specifically limited, A well-known method is employable.

First, a coating film is formed by directly casting a resin composition on an arbitrary supporting substrate. Next, the solvent is removed by drying to the extent that the coating film is at a temperature of 150°C or lower. Thereafter, the coating film is subjected to heat treatment for about 5 to 30 minutes in a temperature range of, for example, 100 to 400°C, preferably 130 to 380°C, in order to imidize the polyamic acid. In this way, an LCP filler containing polyimide layer can be formed on a support base material. If the heat treatment temperature for imidization is lower than 100° C., the dehydration ring closure reaction of the polyimide does not proceed sufficiently. On the contrary, if it exceeds 400° C., the polyimide layer may deteriorate.

When forming a resin film with two or more polyimide layers, after apply|coating and drying the resin composition of a 1st polyamic acid, the resin composition of a 2nd polyamic acid is apply|coated and dried. After that, in the same manner, the resin composition of the third polyamic acid, the resin composition of the fourth polyamic acid, ... As mentioned above, the resin composition of polyamic acid is sequentially applied as many times as necessary and dried. After that, it is preferable to perform imidization by performing heat treatment collectively. Moreover, what is necessary is just that at least 1 of these layers is an LCP filler containing polyimide layer.

Moreover, by performing suitable surface treatment etc. to the arbitrary polyimide layer imidated, it can layer up anew through the process of application|coating of a resin composition, drying, and imidation. In that case, it is not necessary to complete the imidization in the intermediate step, and it is possible to complete the imidization by integrating it in the final step.

In addition, the arbitrary polyimide layer imidated can be thermocompression-bonded with the resin film formed separately.

In addition, the state which has a support base material may be sufficient as a resin film.

In addition, another example of forming a resin film is given.

First, on an arbitrary supporting base material, the resin composition is cast-coated and molded into a film shape. This film-form molded product is heat-dried on a supporting substrate to obtain a gel film having self-supporting properties. After peeling the gel film from the supporting substrate, for example, heat treatment in a temperature range of 100 to 400° C., preferably 130 to 380° C. for about 5 to 30 minutes, imidizing polyamic acid, and LCP filler-containing polyimide layer A resin film comprising a can be obtained. Moreover, you may extend|stretch a resin film as needed.

[Metal Covered Laminate]

The metal-clad laminate of this embodiment is a metal-clad laminate comprising an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer, wherein at least one of the insulating resin layers is a resin film produced by the above method. includes The metal-clad laminate may be a single-sided metal-clad laminate having a metal layer on only one side of the insulating resin layer, or a double-sided metal-clad laminate having a metal layer on both surfaces of the insulating resin layer.

<Insulation resin layer>

The insulating resin layer is composed of a single layer or a plurality of layers, and includes a layer including the resin film. For example, the said resin film may form the non-thermoplastic polyimide layer as a main layer of the insulating resin layer for ensuring a mechanical characteristic and a thermal property. Moreover, the said resin film may form the thermoplastic polyimide layer as an adhesive bond layer which bears adhesive strength with metal layers, such as copper foil. In addition, a "main layer" means the layer which occupies the thickness exceeding 50% of the total thickness of an insulating resin layer.

As a method of manufacturing a metal-clad laminate using a resin film as an insulating resin layer, for example, a method of heat-compressing a metal foil directly to a resin film or through an optional adhesive, or a method such as metal vapor deposition to a resin film. The method of forming a metal layer, etc. are mentioned. In addition, the double-sided metal-clad laminate is formed by, for example, forming a single-sided metal-clad laminate, then making the polyimide layers face each other and pressing and pressing by hot press, or a method in which a metal foil is pressed against the polyimide layer of the single-sided metal-clad laminate. It can be obtained by a method of forming it.

<Metal layer>

The material of the metal layer is not particularly limited, but for example, copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, zirconium, tantalum, titanium, lead, magnesium, manganese, alloys thereof, etc. can be heard Among these, copper or a copper alloy is especially preferable. A metal layer may contain metal foil, and the thing which metal-deposited on the film, the thing which printed the paste, etc. may be sufficient as it. Moreover, a metal foil or a metal plate can be used, and copper foil or a copper plate is preferable.

Although the thickness of a metal layer is although it does not specifically limit since it is set suitably according to the purpose of use of a metal-clad laminated board, For example, the inside of the range of 5 micrometers - 3 mm is preferable, and the inside of the range of 12 micrometers - 1 mm is more preferable. When the thickness of the metal layer is not satisfied to 5 µm, there is a fear that problems such as wrinkles are generated during conveyance in the production of a metal-clad laminate. Conversely, when the thickness of the metal layer exceeds 3 mm, it is hard and the workability deteriorates.

As for the resin film and metal-clad laminate obtained by making it above, the outstanding dielectric characteristic and dimensional stability are compatible with the LCP filler disperse|distributed in polyimide. Therefore, a resin film and a metal-clad laminated board can be used suitably as circuit board materials, such as FPC in various electronic devices, from the point which the loss in high frequency signal transmission is reduced and dimensional stability can also be maintained.

<Example>

The features of the present invention will be described in more detail with reference to Examples below. However, the scope of the present invention is not limited to the examples. In addition, in the following examples, unless otherwise indicated, various measurements and evaluation are based on the following.

[Measurement of viscosity]

The viscosity in 25 degreeC was measured using the E-type viscometer (The Brookfield company make, brand name; DV-II+Pro). The rotation speed was set so that the torque became 10% to 90%, and after 1 minute had elapsed from the start of the measurement, the value when the viscosity was stabilized was read.

[Measurement of coefficient of thermal expansion (CTE)]

The polyimide film was cut into a size of 3 mm in the TD direction × 20 mm in the MD direction, and a thermomechanical analyzer (manufactured by Bruker, trade name; 4000SA) was used to apply a load of 5.0 g in the MD direction to 30° C. at a constant temperature increase rate. The temperature was raised to 260 ° C., and then held at that temperature for 10 minutes, cooled at a rate of 5 ° C./min, and the average coefficient of thermal expansion (coefficient of thermal expansion) from 250 ° C. to 100 ° C. was obtained.

[Measurement of melting point]

Using a differential scanning calorimetry apparatus (DSC, manufactured by SII, trade name; DSC-6200), the temperature was raised from room temperature to 450°C at 1.5°C/min in an inert gas atmosphere, and the melting point was measured.

[Measurement of tensile modulus]

(resin film)

A test piece (width 12.7 mm x length 127 mm) was produced from the resin film using a tension tester (manufactured by Orientec, trade name; Tensilon). Using this test piece, a tensile test was performed at 50 mm/min, and the tensile modulus in 25 degreeC was calculated|required.

(filler)

Randomly take out ten long fibers before filler processing, process each to a length of 200 mm, and use a tensile tester (manufactured by Shimadzu Corporation, trade name; AGS-500NX) in accordance with the standard time test of JISL 1013 (2010). Accordingly, the tensile modulus of elasticity for each of the long fibers was calculated at a tensile rate of 200 mm/min and expressed as an average value.

[Measurement method of average major axis diameter and average minor axis diameter]

Ten fillers were taken out at random, observed independently using a stereoscopic microscope, and the major axis diameter and minor axis diameter of each of the taken out fillers were measured and obtained as an average value.

[Measurement of true specific gravity]

The true specific gravity was measured by the pycnometer method (liquid phase displacement method) using the continuous automatic powder true density measuring apparatus (The Seishin Industrial Co., Ltd. make, brand name; AUTO TRUE DENSERMAT-7000).

[Aggregation evaluation]

When the varnish was applied to the support, the presence or absence of non-passing solids was checked when 500 mL of the varnish was passed through a 500 µm gap coater.

[Measurement of dielectric constant and dielectric loss tangent]

(resin film)

Using a vector network analyzer (manufactured by Agilent, trade name; Vector Network Analyzer E8363C) and an SPDR resonator, the dielectric constant (ε1) and dielectric loss tangent (Tanδ1) of the resin film (cured resin film) at a frequency of 10 GHz were measured. In addition, the resin film used for a measurement is temperature; 24-26°C, humidity; It is allowed to stand for 24 hours under the conditions of 45 to 55%.

(liquid crystal polymer)

A vector network analyzer (manufactured by Agilent, trade name; Vector Network Analyzer E8363C) and an SPDR resonator were used to measure the dielectric constant (ε1) and dielectric loss tangent (Tanδ1) of a sample obtained by melt-molding a liquid crystal polymer into a plate shape at a frequency of 1 GHz. . In addition, the sample used for measurement is temperature; 24-26°C, humidity; It is allowed to stand for 24 hours under the conditions of 45 to 55%.

[Cross-section observation]

1) Preparation of sample for measurement

After embedding the sample with an epoxy resin so that the observation surface (the cross section in the thickness direction) of the sample of the copper clad laminate (TD; 10 mm × MD; 10 mm) is in the MD direction, using a rotary plate type polishing machine, a plurality of emery paper (up to #1200), buffing (up to 1 µm of diamond particle paste), and chemical polishing with a chemical to prepare a measurement sample.

2) Observation of the sample for measurement

The observation surface of the sample for measurement was observed at a magnification of 200 to 3000 times using a scanning electron microscope (SEM).

The symbol used for the Example and the comparative example shows the following compounds.

PMDA: pyromellitic dianhydride

BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride

m-TB: 2,2'-dimethyl-4,4'-diaminobiphenyl

DMAc: N,N-dimethylacetamide

Filler 1: liquid crystal polymer having a polyester structure, short fibers, average minor axis diameter; 28 μm, average major axis diameter; 1000 μm, melting point (Tm); 350°C, true specific gravity; 1.4, tensile modulus; 85 GPa, relative permittivity; 3.1, dielectric loss tangent; 0.0010

Filler 2: liquid crystal polymer having a polyester structure, short fibers, average minor axis diameter; 28 μm, average major axis diameter; 500 μm, melting point (Tm); 350°C, true specific gravity; 1.4, tensile modulus; 85 GPa, relative permittivity; 3.1, dielectric loss tangent; 0.0010

Filler 3: liquid crystal polymer having a polyester structure, short fibers, average minor axis diameter; 28 μm, average major axis diameter; 1000 μm, melting point (Tm); 330°C, true specific gravity; 1.4, tensile modulus; 160 GPa, relative permittivity; 3.4, dielectric loss tangent; 0.0020

Filler 4: liquid crystal polymer having a polyester structure, short fibers, average minor axis diameter; 14 μm, average major axis diameter; 1000 μm, melting point (Tm); 330°C, true specific gravity; 1.4, tensile modulus; 140 GPa, relative permittivity; 3.4, dielectric loss tangent; 0.0020

Filler 5: liquid crystal polymer particles having a polyester structure, irregular shape, average minor axis diameter; 8 μm, average major axis diameter; 14 μm, melting point (Tm); 320°C, true specific gravity; 1.4, relative permittivity; 3.4, dielectric loss tangent; 0.0010

[Example 1]

In a 300 ml separable flask, 17 g of m-TB (82 mmol) and 230 g of DMAc were charged, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 4.5 g of PMDA (20 mmol), 18 g of BPDA (62 mmol), and 4.2 g of Filler 1 were added, followed by stirring at room temperature for 18 hours, and resin solution 1 (viscosity; 30,000 cps, nonvolatile component) The content rate of filler 1 with respect to; 10 volume%) was prepared.

Resin solution 1 was applied to a thickness of about 350 μm on a copper foil (electrolytic copper foil, thickness: 12 μm), and dried at 130° C. for 5 minutes to form a resin layer. Thereafter, heat treatment was performed stepwise from 150°C to 380°C over 20 minutes to complete imidization, and a copper clad laminate 1 was prepared.

The copper foil of the copper clad laminated board 1 was removed by etching, and the resin film 1 (thickness; 48 micrometers) was prepared. The resin film 1 had a CTE of 13 ppm/K, a dielectric constant of 3.1, and a dielectric loss tangent of 0.0039.

[Example 2]

Resin solution 2 (viscosity; 34,000 cps) was carried out in the same manner as in Example 1 except that the amount of filler 1 added in Example 1 was replaced with 17 g, and after filler 1 was added, 94 g of DMAc was further added and added. , the content rate of the filler 1 with respect to the nonvolatile component; 30 vol%) was prepared.

Resin solution 2 was applied to a thickness of about 350 μm on a copper foil (electrolytic copper foil, thickness; 12 μm), and dried at 130° C. for 5 minutes to form a resin layer. After that, heat treatment was performed stepwise from 150°C to 380°C over 20 minutes to complete imidization, and a copper clad laminate 2 was prepared.

The copper foil of the copper clad laminated board 2 was removed by etching, and the resin film 2 (thickness; 37 micrometers) was prepared. The resin film 2 had a CTE of 3 ppm/K, a relative permittivity of 2.3, and a dielectric loss tangent of 0.0035.

[Example 3]

In the same manner as in Example 1, except that 4.3 g of Filler 2 was added instead of 4.2 g of Filler 1 in Example 1, and 25 g of DMAc was further added after adding Filler 2 Thus, resin solution 3 (viscosity; 28,000 cps, content rate of filler 2 with respect to nonvolatile components; 10 vol%) was prepared.

The resin solution 3 was applied to a thickness of about 350 μm on a copper foil (electrolytic copper foil, thickness; 12 μm), and dried at 130° C. for 5 minutes to form a resin layer. Thereafter, heat treatment was performed stepwise from 150°C to 380°C over 20 minutes to complete imidization, and a copper-clad laminate 3 was prepared.

The copper foil of the copper clad laminate 3 was removed by etching, and the resin film 3 (thickness; 55 micrometers) was prepared. The resin film 3 had a CTE of 15 ppm/K, a dielectric constant of 2.8, and a dielectric loss tangent of 0.0037.

[Example 4]

A resin solution 4 (viscosity; 30,000 cps, content of filler 2 with respect to nonvolatile components; 30% by volume) was prepared in the same manner as in Example 2 except that filler 2 was used instead of filler 1 of Example 2.

Resin solution 4 was applied to a thickness of about 350 μm on a copper foil (electrolytic copper foil, thickness; 12 μm), and dried at 130° C. for 5 minutes to form a resin layer. Thereafter, heat treatment was performed stepwise from 150° C. to 380° C. over 20 minutes to complete imidization, and a copper clad laminate 4 was prepared.

The copper foil of the copper clad laminated board 4 was removed by etching, and the resin film 4 (thickness; 67 micrometers) was prepared. The resin film 4 had a CTE of 8 ppm/K, a relative permittivity of 2.5, and a dielectric loss tangent of 0.0034.

[Example 5]

Resin solution 5 in the same manner as in Example 1 except that 34 g of Filler 2 was added instead of 4.2 g of Filler 1 in Example 1, and that after addition of Filler 2, 180 g of DMAc was further added. (Viscosity; 45,000 cps, content rate of filler 2 with respect to a nonvolatile component; 60 volume%) was prepared.

Resin solution 5 was applied to a thickness of about 350 μm on a copper foil (electrolytic copper foil, thickness; 12 μm), and dried at 130° C. for 5 minutes to form a resin layer. After that, heat treatment was performed stepwise from 150°C to 380°C over 20 minutes to complete imidization, and a copper clad laminate 5 was prepared.

The copper foil of the copper clad laminated board 5 was removed by etching, and the resin film 5 (thickness; 67 micrometers) was prepared. The resin film 5 had a CTE of 2 ppm/K, a dielectric constant of 3.0, and a dielectric loss tangent of 0.0029.

[Example 6]

A resin solution 6 (viscosity; 30,000 cps, content of filler 3 with respect to nonvolatile components; 10% by volume) was prepared in the same manner as in Example 1 except that filler 3 was used instead of filler 1 of Example 1.

Resin solution 6 was applied to a thickness of about 350 μm on a copper foil (electrolytic copper foil, thickness; 12 μm), and dried at 130° C. for 5 minutes to form a resin layer. Thereafter, heat treatment was performed stepwise from 150°C to 380°C over 20 minutes to complete imidization, and a copper-clad laminate 6 was prepared.

The copper foil of the copper clad laminate 6 was removed by etching, and the resin film 6 (thickness; 50 micrometers) was prepared. The resin film 6 had a CTE of 18 ppm/K, a dielectric constant of 3.1 and a dielectric loss tangent of 0.0039.

[Example 7]

A resin solution 7 (viscosity; 28,000 cps, content of filler 4 with respect to nonvolatile components; 10% by volume) was prepared in the same manner as in Example 1 except that Filler 4 was used instead of Filler 1 of Example 1.

Resin solution 7 was applied to a thickness of about 350 μm on a copper foil (electrolytic copper foil, thickness; 12 μm), and dried at 130° C. for 5 minutes to form a resin layer. Thereafter, heat treatment was performed stepwise from 150°C to 380°C over 20 minutes to complete imidization, and a copper-clad laminate 7 was prepared. The cross-sectional structure of the obtained copper clad laminate 7 is shown in FIG. The cross section in the minor axis direction of the filler 4 orientated in the polyimide was confirmed.

The copper foil of the copper clad laminated board 7 was removed by etching, and the resin film 7 (thickness; 45 micrometers) was prepared. The resin film 7 had a CTE of 16 ppm/K, a dielectric constant of 3.0, and a dielectric loss tangent of 0.0040.

(Comparative Example 1)

Polyamic acid solution 1 was applied to a thickness of about 500 μm on a copper foil (electrolytic copper foil, thickness: 12 μm), and dried at 130° C. for 5 minutes to form a resin layer. After that, heat treatment was performed stepwise from 150°C to 380°C over 20 minutes to complete imidization, and a copper-clad laminate 8 was prepared.

The copper foil of the copper clad laminated board 8 was removed by etching, and the resin film 8 (thickness; 41 micrometers) was prepared. The resin film 8 had a CTE of 19 ppm/K, a relative permittivity of 3.4, a dielectric loss tangent of 0.0041, a true specific gravity of 1.4, and a tensile modulus of 8 GPa.

(Comparative Example 2)

140 g of polyamic acid solution 1 and 8.3 g of filler 3 were mixed and stirred to prepare resin solution 9 (content rate of filler 3 with respect to nonvolatile components; 30 vol%).

Resin solution 9 was applied to a thickness of about 350 μm on a copper foil (electrolytic copper foil, thickness; 12 μm), and the aggregated solids of the filler were clogged between the coater gaps. Clogging of solids also occurred even when the gap was expanded to 500 μm.

(Reference Example 1)

A resin solution 10 (viscosity; 28000 cps, content of filler 5 relative to nonvolatile components; 30% by volume) was prepared in the same manner as in Example 1 except that 7 g of Filler 5 was used instead of Filler 1 of Example 1.

The resin solution 10 was applied to a thickness of about 350 μm on a copper foil (electrolytic copper foil, thickness: 12 μm), and dried at 130° C. for 5 minutes to form a resin layer. Thereafter, heat treatment was performed stepwise from 150°C to 380°C over 20 minutes to complete imidization, and a copper clad laminate 10 was prepared.

The copper foil of the copper clad laminate 10 was removed by etching, and the resin film 10 (thickness; 45 micrometers) was prepared. The resin film 10 had a CTE of 33 ppm/K, a dielectric constant of 3.3, and a dielectric loss tangent of 0.0030.

The above results are summarized and shown in Table 1.

From the results of Examples 1 to 7 and Comparative Example 1, it was confirmed that by adding the fillers 1 to 4, the dielectric constant and dielectric loss tangent could be reduced while suppressing an increase in CTE. In Comparative Example 2 (blending method), fillers were entangled with each other in the resin solution, aggregation occurred, and coating became impossible. Further, in Reference Example 1, although the dielectric loss tangent was lowered, the CTE increased remarkably.

As mentioned above, although embodiment of this invention was described in detail for the purpose of illustration, this invention is not restrict|limited to the said embodiment, and various deformation|transformation is possible.

Claims (18)

The following components (A) and (B),
(A) the polyamic acid formed by making a tetracarboxylic-acid anhydride component and a diamine component react;
and
(B) Filler with shape anisotropy containing liquid crystal polymer
A resin composition containing The resin composition according to claim 1, wherein the ratio (L/D) of the average major axis diameter (L) to the average minor axis diameter (D) of the filler of the component (B) is in the range of 3 to 200. The resin composition according to claim 1 or 2, wherein an average major axis diameter (L) of the filler of component (B) is in a range of 50 to 3000 µm, and an average minor axis diameter (D) is in a range of 1 to 50 µm. . The resin composition according to any one of claims 1 to 3, wherein the content of the filler of the component (B) is in the range of 1 to 70% by volume based on the total amount of the component (A) and the component (B). The resin composition according to any one of claims 1 to 4, wherein the liquid crystal polymer has a melting point of 280°C or higher. The resin composition according to any one of claims 1 to 5, wherein the liquid crystal polymer has a polyester structure. The resin composition according to any one of claims 1 to 6, wherein the filler of the component (B) has a tensile modulus of elasticity of 20 GPa or more in the major axis direction. The ratio of the tensile modulus of elasticity in the major axis direction of the filler of the component (B) to the tensile modulus of elasticity of a polyimide obtained by curing the polyamic acid of the component (A) according to any one of claims 1 to 7 A resin composition having a ratio of 1 or more. The ratio of the true specific gravity of the filler of the said (B) component to the true specific gravity of the polyimide obtained by hardening the polyamic acid of the said (A) component in any one of Claims 1-8 of 0.5-2.0 resin composition within the range. The resin composition according to any one of claims 1 to 9, wherein the liquid crystal polymer of the component (B) has a dielectric constant in the range of 2.0 to 3.5 at 1 GHz and a dielectric loss tangent of less than 0.003. It is a manufacturing method of the resin composition in any one of Claims 1-10,
Before the reaction of synthesizing the polyamic acid by reacting the tetracarboxylic anhydride component with the diamine component is completed, a filler having shape anisotropy containing the liquid crystal polymer of the component (B) is added. A method for producing a resin composition. 12. The method of claim 11, wherein before the viscosity of the reaction solution of the tetracarboxylic anhydride component and the diamine component reaches 1500 cps, a filler having shape anisotropy containing the liquid crystal polymer of the component (B) is added and mixed. A method for producing a resin composition. A resin film comprising a polyimide layer,
The said polyimide layer contains a polyimide and the filler which has shape anisotropy containing the liquid crystal polymer disperse|distributed in the said polyimide, The resin film characterized by the above-mentioned. The resin film according to claim 13, wherein the polyimide layer has a coefficient of thermal expansion of 30 ppm/K or less. The resin film of Claim 13 or 14 whose dielectric constant in 10 GHz of the said polyimide layer exists in the range of 2.0-3.8, and a dielectric loss tangent is 0.004 or less. The resin film according to any one of claims 13 to 15, wherein the content of the filler having shape anisotropy containing the liquid crystal polymer relative to the total amount of the resin component in the polyimide layer is in the range of 1 to 70 vol%. The resin film according to any one of claims 13 to 16, wherein the longitudinal direction of the liquid crystal polymer is oriented in the polyimide layer. A metal clad laminate comprising an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer,
At least one layer of the said insulating resin layer is the resin film in any one of Claims 13-17, The metal-clad laminated board characterized by the above-mentioned.

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