JP2021105149A - Method for manufacturing resin film, and method for manufacturing metal-clad laminated plate - Google Patents

Abstract

To provide a resin film having excellent external appearance and surface smoothness due to that excessive aggregation of different kinds of organic polymer particles dispersed in the resin film is suppressed.SOLUTION: A method for manufacturing a resin film includes steps of preparing a resin composition containing a solvent, a soluble resin soluble in the solvent, and organic polymer particles insoluble in the solvent, and of heat-treating the resin composition to obtain a resin film containing organic polymer particles in a solidified product of the soluble resin. The heat-treatment satisfies that: (a) when a melting point of the organic polymer particles is Tx[unit;°C], and a maximum arrival temperature of the heat-treatment is Tmax[unit;°C], Tx and Tmax are in a relationship of Tx≤Tmax; and (b) when a temperature is Tx-40°C in a temperature rising process up to Tmax in the heat-treatment, a content of volatile components contained in the resin composition is 0.5 wt.% or less based on a content of nonvolatile components in the resin composition.SELECTED DRAWING: None

Description

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

Flexible printed circuit boards (FPCs) can be mounted three-dimensionally and at high density even in a limited space, so they can be used for wiring of moving parts of electronic devices, cables, connectors, and other parts. It has expanded and is installed in equipment in many fields. Along with this, the environment in which FPC is used is diversifying, and the required performance is also becoming more sophisticated. For example, high transparency is required for applications such as displays, and higher heat resistance, heat dissipation, and thermal conductivity are required for applications for automobiles.

Examples of the resin widely used for the insulating layer of the FPC include a liquid crystal polymer (LCP) having excellent heat resistance, a polyimide, and a fluororesin. In general, LCP is difficult to dissolve in a general-purpose solvent, has a low melt viscosity, has little molecular entanglement, and is extremely easy to orient, and is difficult to handle in terms of production and processing as a film. Further, there may be a problem that the adhesiveness to the copper foil and the coefficient of thermal expansion (CTE) in the thickness direction when formed into a film are large. The bottleneck of polyimide is the change in characteristics due to moisture absorption, and the high CTE and cost of fluororesin are bottlenecks.

The problems of each polymer as described above are reaching an area where it is difficult to deal with them only by improving their chemical structure and manufacturing conditions. For example, if the CTE is lowered, the adhesiveness is deteriorated, and if the adhesiveness is increased, the heat resistance is lowered.

As one of the methods for improving the properties of a polymer, the formation of a polymer alloy containing two or more kinds of polymer components is known. The polymer alloy broadly refers to a polymer multi-component material, and includes a block polymerization method, a graft polymerization method, a physical blending method, and the like.
For example, Patent Document 1 reports that by blending polybenzimidazole with a polyimide having a high elastic modulus, the adhesiveness is improved while maintaining the elastic modulus. Further, in Patent Document 2, by blending a small amount of condensation-based LCP with polyethylene naphthalate having excellent mechanical properties, heat resistance, gas blocking property, and dimensional stability at high temperature, weather resistance is improved without impairing the above properties. There is an example.

In the field of circuit board materials as well, it has been reported that high performance is achieved by forming polymer alloys. Patent Document 3 reports a prepreg having improved electrical properties by blending LCP with a thermosetting epoxy resin. Further, Patent Document 4 presents a method for producing a polyimide film in which highly heat-resistant polyimide and low-hygroscopic fluororesin particles are combined.

Japanese Patent No. 5145627 Special Fair 6-2870 Japanese Patent No. 6295013 Japanese Patent No. 6387181

As described above, the improvement of polymer properties by polymer alloy is utilized in a wide range of fields. In general, many dissimilar polymers do not show compatibility or miscibility and are phase-separated. On the other hand, when the solvent-insoluble polymer particles are dispersed in a liquid polymer dissolved in a solvent, a dispersion stabilizer such as a surfactant may be used, or the viscosity of the dispersion may be increased to reduce the movement speed of the particles. It is possible to disperse by doing. A uniform polymer blend film can be obtained by applying the dispersion liquid to a substrate and heat-treating it. At that time, a high temperature may be required in order to improve / secure the electrical, mechanical and thermal properties by reducing the low molecular weight substances such as the solvent remaining on the film. However, when the polymer particles have a melting point, if the melting point is exceeded during the heat treatment, coalescence occurs between the droplets of the molten particles, and the polymer particles appear as agglomerates in the form of spots and spoil the appearance. Further, when it appears as a protrusion on the film surface, it may be transferred to a healthy part at the time of winding or laminating, or the equipment may be damaged such as a coater defect.

Therefore, an object of the present invention is to provide a resin film in which excessive aggregation of dissimilar organic polymer particles dispersed in the resin film is suppressed and the appearance and surface smoothness are good.

The method for producing a resin film of the present invention includes a step of preparing a resin composition containing a solvent, a soluble resin soluble in the solvent, and organic polymer particles insoluble in the solvent, and a heat treatment of the resin composition. The step of obtaining a resin film containing the organic polymer particles in the solidified product of the soluble resin is included.
In the method for producing a resin film of the present invention, the heat treatment is performed under the following conditions (a) and (b);
(A) When the melting point of the organic polymer particles is Tx [unit; ° C] and the maximum temperature reached by the heat treatment is Tmax [unit; ° C], the relationship of the following formula (1) is satisfied;
Tx ≦ Tmax ・ ・ ・ (1)
(B) When the temperature is Tx-40 ° C. in the process of raising the temperature to Tmax in the heat treatment, the content of the volatile component contained in the resin composition is 0 with respect to the content of the non-volatile component in the resin composition. .5% by weight or less;
It satisfies.

In the method for producing a resin film of the present invention, the soluble resin may be at least one selected from polyamide, polyimide, polyester, polyether and precursors thereof.

In the method for producing a resin film of the present invention, the organic polymer particles may be made of a liquid crystal polymer.

In the method for producing a resin film of the present invention, the Tx may be 240 ° C. or higher.

In the method for producing a resin film of the present invention, the boiling point of the solvent may be Tx or less.

In the method for producing a resin film of the present invention, the ratio of the organic polymer particles to the non-volatile component of the resin film may be in the range of 5 to 99% by volume.

In the method for producing a resin film of the present invention, the thickness of the resin film may be in the range of 2 to 150 μm.

The method for producing a metal-clad laminate of the present invention is a method for producing 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 of the insulating resin layers is made of a resin film produced by the method according to any one of the above.

According to the method of the present invention, by satisfying the conditions (a) and (b), excessive aggregation of dissimilar organic polymer particles dispersed in the resin film is suppressed, and the appearance and surface smoothness are good. A resin film can be produced. The resin film produced by the method of the present invention can be suitably used as a circuit board material for FPCs and the like in various electronic devices.

It is an appearance photograph of the resin layer of the copper-clad laminate produced in Example 1. It is a cross-sectional photograph of the resin layer of the copper-clad laminate produced in Example 1. It is an appearance photograph of the resin layer of the copper-clad laminate produced in Comparative Example 1.

Hereinafter, embodiments of the present invention will be described.

The method for producing a resin film according to an embodiment of the present invention includes a step of preparing a resin composition (step 1) and a step of heat-treating the resin composition to obtain a resin film containing organic polymer particles (step 2). ) Is included.

[Step 1 (Step of preparing the resin composition)]
In this step, a resin composition containing a solvent, a soluble resin soluble in the solvent, and organic polymer particles insoluble in the solvent is prepared.

<Solvent>
Examples of the solvent include N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N, N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2-butanone, and dimethyl sulfoxide. Organic solvents such as (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethylformamide, cyclohexanone, dioxane, tetrahydrofuran, diglime, triglime, cresol, acetone, methylisobutylketone 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 content of the solvent is not particularly limited, but it is preferable to adjust the content of the solvent so that the solid content concentration in the resin composition is about 5 to 50% by weight.

<Soluble resin>
The soluble resin is not particularly limited as long as it is a material soluble in the above solvent, but is preferably a resin having high heat resistance and capable of heating at a temperature exceeding the melting point of the organic polymer particles. By heating above the melting point of the organic polymer particles, the organic polymer particles melt and flow, and the voids in the matrix resin of the resin film can be filled. As such a resin, for example, polyamide, polyimide, polyester, polyether or a precursor resin thereof is preferable, and in particular, polyamic acid which is a precursor of polyimide which is often heated at about 400 ° C. for imidization is used. preferable. The soluble resin is not limited to one type, and two or more types may be mixed and used.

[polyamide]
The polyamide is not particularly limited, and is a polymer having an amide bond (-CO-NH-) in the skeleton. Such a polyamide can be produced by a known method such as a ring-opening reaction of lactam, polymerization of a diamine component and a dicarboxylic acid derivative, and polymerization from a carboxylic acid derivative having an amino group. From the viewpoint of heat resistance, polyamide composed of an aromatic skeleton (also collectively referred to as aramid) is preferable.

[Polyimide]
Polyimide is a polymer having an imide group represented by the following general formula (1). Further, when it has an amide group or an ether bond, it may be referred to as a polyamide-imide or a polyetherimide, but in the present specification, these are generally referred to as polyimide. Such a polyimide uses a method of addition polymerization of a maleimide component and a diamine component, a method of cross-linking a bismaleimide and an aromatic cyanate ester, and a substantially equimolar amount of a diamine component and an acid dianhydride component. It can be produced by a known method of polymerizing in an organic polar solvent. In this case, the molar ratio of the acid dianhydride component to the diamine component may be adjusted in order to bring the viscosity into a desired range, and the range is, for example, within the range of the molar ratio of 0.98 to 1.03. It is preferable to do so.

In the general formula (1), Ar ₁ represents a tetravalent group derived from an acid anhydride containing a tetracarboxylic dianhydride residue, and R ₂ represents a divalent divalent residue derived from diamine. , N is an integer of 1 or more.

As the acid dianhydride, for example, _{an aromatic tetracarboxylic dianhydride represented by O (OC) 2-} Ar _1- (CO) ₂ O is preferable, and the following aromatic acid anhydride residue is designated as _{Ar 1.} What is given is exemplified.

The acid dianhydride can 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 Use one selected from anhydride (BTDA), 3,3', 4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA), and 4,4'-oxydiphthalic acid dianhydride (ODPA). Is preferable.

As the diamine, for example, _{a diamine represented by H 2} N-R _2- NH ₂ is preferable, and a diamine in which the following diamine residue is _{given as R 2} is exemplified.

Among these diamines, diaminodiphenyl ether (DAPE), 2,2'-dimethyl-4,4'-diaminobiphenyl (m-TB), para-phenylenediamine (p-PDA), 1,3-bis (4-amino) Phenoxy) 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 ones.

The synthesized polyamic acid is usually advantageous to be used as a reaction solvent solution, but if necessary, it can be concentrated, diluted or replaced with another organic solvent to form a resin composition. The method for imidizing the polyamic acid is not particularly limited, and for example, a heat treatment such as heating in the solvent under a temperature condition in the range of 80 to 400 ° C. for 1 to 24 hours is preferably adopted.

[polyester]
The polyester is not particularly limited, and is a polymer having an ester bond (-COO-) in the skeleton. Such a polyester can be produced by a known method such as polymerization from diols and a dicarboxylic acid derivative. From the viewpoint of heat resistance, polyester composed of an aromatic skeleton is preferable.

[Polyester]
The polyether is not particularly limited, and is a polymer having an ether bond (-O-) in the skeleton. Such a polyether can be produced by a known method such as radical polymerization of phenols. From the viewpoint of heat resistance, a polyether composed of an aromatic skeleton is preferable.

[precursor]
The term "precursor" refers to a substance in a stage before the substance is produced, and in the present specification, an oligomer is also included as a precursor of the resin. A case where it is preferable to use a precursor is a case where the precursor is soluble even in a polymer insoluble in a solvent. Specifically, most of all aromatic polyimides are insoluble in general-purpose solvents, but the precursor polyamic acid is easily dissolved in amide-based solvents. Further, polyester can be solvent-soluble even when it is insoluble in a solvent in a high molecular weight form. In general, the oligomer refers to a polymer having a low degree of polymerization, and in the present specification, it refers to a polymer having a molecular weight of 5000 or less within a range of 2 to 50 repetitions. When the oligomer has an active site, it can react and increase the degree of polymerization by giving energy such as heating, increasing the solution concentration, and adding an activator or a cross-linking agent.

<Catalyst, curing agent and curing accelerator>
The resin composition according to one embodiment may contain a curing agent. The curing agent is not particularly limited, and a curing agent suitable for the resin can be used. For example, imidazole compounds, acid anhydrides, dicyandiamides, hydrazides, amine adducts, sulfonium salts, formaldehyde, ketimine, tertiary amines are exemplified.

The content of the curing agent is not particularly limited and can be appropriately selected depending on the resin component to be used and the curing conditions. For example, the content of the curing agent is preferably 5 to 110% by weight based on the above-mentioned soluble resin. More preferably, it is 20 to 90% by weight.

Further, a curing accelerator may be used in combination with or alone with the above-mentioned curing agent. The curing accelerator is not particularly limited, and examples thereof include organic phosphine compounds.

<Organic polymer particles>
The material of the organic polymer particles is not particularly limited as long as it is a resin having a melting point and insoluble in the above solvent. For example, a liquid crystal polymer, a fluororesin, an olefin resin, a polyester, a polyphenylene ether, or a polyether is used. Ketones, polyphenylene sulfides and the like are preferable, and liquid crystal polymers are particularly preferable from the viewpoint of being effective in lowering the dielectric adjacency and lowering the moisture absorption of the resin film. The liquid crystal polymer has almost no frequency dependence of the dielectric properties, has very excellent dielectric properties, and also contributes to the improvement of flame retardancy. Therefore, by blending this, the dielectric properties and flame retardancy of the resin film can be achieved. The sex can be improved. When blended for the purpose of improving the dielectric properties of the resin film, the liquid crystal polymer particles have a relative permittivity at 10 GHz, preferably in the range of 2.1 to 4.0, more preferably 2.8 to 4.0, as a simple substance. It is preferable to use a film having a dielectric loss tangent in the range of 3.8 and having a dielectric loss tangent at 10 GHz, preferably 0.0030 or less, more preferably 0.0020 or less, still more preferably 0.0015 or less. The melting point of the liquid crystal polymer is sometimes referred to as the liquid crystal transition temperature or the liquid crystal conversion temperature, but in the present specification, it is collectively referred to as the melting point. The melting point is preferably 220 ° C. or higher. More preferably 250 ° C. or higher, still more preferably 290 ° C. or higher. If the melting point falls below the above range, it may melt in the manufacturing flow of electronic devices and the like, causing changes in characteristics.

The liquid crystal polymer is not particularly limited, and examples thereof include known thermotropic liquid crystal polyesters and polyester amides derived from the compounds classified into the following (1) to (4) and their derivatives. ..
(1) Aromatic or aliphatic dihydroxy compounds (2) Aromatic or aliphatic dicarboxylic acids (3) Aromatic hydroxycarboxylic acids (4) Aromatic diamines, aromatic hydroxyamines or aromatic aminocarboxylic acids

As a typical example of the liquid crystal polymer obtained from these raw material compounds, it is a copolymer having two or more combinations selected from the structural units represented by the following formulas (a) to (j) and is represented by the formula (a). A copolymer containing either a structural unit or a structural unit represented by the formula (e) is preferable, and a copolymer containing the structural unit represented by the formula (a) and the structural unit represented by the formula (e) is more preferable. .. Further, as the number of aromatic rings in the liquid crystal polymer increases, the effect of improving the dielectric properties and flame retardancy can be expected. Therefore, the compound containing an aromatic dihydroxy compound as the above (1) and the aromatic dicarboxylic acid as the above (2). Is preferable.

Further, the shape of the organic polymer particles is not limited, and examples thereof include spherical, amorphous, plate-like, and fibrous (milled fiber, chopped fiber, cut fiber, etc.). The organic polymer particles preferably have an average particle diameter _{D 50} in the range of 6 to 20 .mu.m, more preferably in the range of 8 to 15 m. Here, the average particle size D ₅₀ is a value at which the cumulative value in the frequency distribution curve obtained by the volume-based particle size distribution measurement by the laser diffraction / scattering method is 50%. When the average particle size D ₅₀ is within this range, a resin film having a good appearance can be obtained without deteriorating the surface smoothness when the resin film is formed by the resin composition.

As the organic polymer particles, commercially available products can be appropriately selected and used. For example, in the case of liquid crystal polymer particles, as low-dielectric liquid crystal polymers, Ueno Pharmaceutical Co., Ltd., UENO LCP (registered trademark), Ceranies Japan Co., Ltd., VECTRA / ZENITE (registered trademark), Polyplastics Co., Ltd. Ross (registered trademark), Toray Co., Ltd., Siberus (registered trademark), JXTG Energy Co., Ltd., Zider (registered trademark) and the like can be preferably used. Further, two or more different organic polymer particles may be used in combination as the organic polymer particles.

<Arbitrary ingredient>
If necessary, a resin component other than the organic polymer particles, a flame retardant, a cross-linking agent, an inorganic filler, a plasticizer, a coupling agent, a pigment, and the like can be appropriately added to the resin composition.

<Viscosity>
The viscosity of the resin composition is preferably in the range of, for example, 3000 cps to 100,000 cps, and is preferably in the range of 5000 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>
The resin composition can be prepared, for example, by preparing a solution of a soluble resin using a solvent, adding organic polymer particles to the solution, and mixing them uniformly. The entire amount of the organic polymer particles may be added at one time, or may be added little by little in several portions. Alternatively, a soluble resin solution may be prepared using a solvent in which organic polymer particles are dispersed in advance.

[Step 2 (Step to obtain resin film)]
In step 2, the resin composition obtained in step 1 is heat-treated to obtain a resin film containing organic polymer particles in the solidified product of the soluble resin. The "solidified product" also includes a cured product.
The method for obtaining a resin film by heat-treating the resin composition in this step 2 is not particularly limited, and a known method can be adopted. Here, a case where the soluble resin in the resin composition is a polyamic acid will be described as an example.

First, the resin composition is cast and applied directly onto an arbitrary supporting base material to form a coating film. Next, the solvent is dried and removed from the coating film at a temperature of 150 ° C. or lower to some extent. Then, the coating film is heat-treated for about 5 to 30 minutes in a temperature range of, for example, 100 to 400 ° C., preferably 130 to 380 ° C. for imidization of the polyamic acid. In this way, a polyimide resin film can be formed on the supporting base material.
When the resin film is formed of two or more polyimide layers, the resin composition of the first polyamic acid is applied and dried, and then the resin composition of the second polyamic acid is applied and dried. After that, in the same manner, the resin composition of the third polyamic acid, then the resin composition of the fourth polyamic acid, and so on, the resin composition of the polyamic acid is applied as many times as necessary. Apply sequentially and dry. After that, it is preferable to carry out heat treatment collectively to carry out imidization. If the heat treatment temperature for imidization is lower than 100 ° C., the dehydration ring closure reaction of the polyimide does not proceed sufficiently, and conversely, if it exceeds 400 ° C., the polyimide layer may be deteriorated.
Further, by appropriately performing an appropriate surface treatment or the like on the imidized arbitrary polyimide layer, a new layer can be layered through the steps of coating, drying and imidizing the resin composition. In that case, it is not necessary to complete the imidization in the intermediate step, and the imidization can be completed collectively in the final step.
Further, any imidized polyimide layer can be heat-bonded to a separately formed resin film.
The resin film may be in a state of having a supporting base material.

Another example of forming a polyimide resin film will be given.
First, the resin composition is cast-coated on an arbitrary supporting base material and molded into a film. This film-like molded product is heat-dried on a supporting base material to obtain a gel film having self-supporting properties. After the gel film is peeled off from the supporting base material, it is heat-treated in a temperature range of, for example, 100 to 400 ° C., preferably 130 to 380 ° C. for about 5 to 30 minutes to imidize the polyamic acid to obtain a polyimide resin film.

The heat treatment in step 2 is carried out so as to satisfy the following conditions (a) and (b).

<Condition (a)>
When the melting point of the organic polymer particles is Tx [unit: ° C] and the maximum temperature reached by the heat treatment is Tmax [unit; ° C], the relationship of the following formula (1) is satisfied.
Tx ≦ Tmax ・ ・ ・ (1)
When the condition (a) is satisfied, the organic polymer particles are melted and flowed by heating above the melting point of the organic polymer particles, and the voids of the matrix resin of the resin film can be filled. Here, Tx is preferably equal to or higher than the boiling point of the solvent, and more preferably 240 ° C. or higher. When Tx is equal to or higher than the boiling point of the solvent, the solvent can be efficiently discharged to the outside of the system. In other words, it is preferable to use a solvent having a boiling point of Tx or less.

As a preferable combination of the organic polymer particles satisfying the condition (a) and the soluble resin, for example, when the organic polymer particles are liquid crystal polymer particles and the soluble resin is polyamic acid, the melting point Tx of the liquid crystal polymer particles is 280 ° C. for type I. The ultra-type II is 220 ° C. or higher, and the maximum ultimate temperature Tmax of the heat treatment for imidizing the polyamic acid is about 380 to 400 ° C.

<Condition (b)>
When the temperature is Tx-40 ° C. in the process of raising the temperature to Tmax in the heat treatment, the content of the volatile component contained in the resin composition is 0.5% by weight or less with respect to the content of the non-volatile component of the resin composition. There is.
By satisfying the condition (b), the residual amount of the solvent can be sufficiently reduced by the time the temperature reaches Tx in the temperature raising process up to Tmax regardless of the heating rate and time of the heat treatment. .. As a result, aggregation and fusion due to the flow of a plurality of organic polymer particles caused by the residual solvent can be suppressed. In addition, the formation of voids between the matrix resin and the organic polymer particles can be suppressed. As long as the condition (b) is satisfied, the heating rate and time in the heat treatment can be arbitrarily adjusted.

[Resin film]
The resin film of the present embodiment is produced by the above method. When the soluble resin is a polyamic acid, the matrix resin of the resin film is an imidized polyimide, in which organic polymer particles are dispersed.

<Mixing amount>
The ratio of the organic polymer particles to the non-volatile components of the resin film can be appropriately set according to the purpose of use, but is preferably in the range of 5 to 99% by volume, preferably in the range of 20 to 80% by volume. More preferred. If the volume ratio of the organic polymer particles is less than 5% by volume, the effect of blending (for example, in the case of liquid crystal polymer particles, the effect of improving the dielectric properties) may be insufficient, and if it exceeds 99% by volume, a resin film is formed. May become difficult or the resin film may become brittle. The volume ratio of the organic polymer particles in the resin film can be calculated from the imaging image by a three-dimensional transmission electron microscope (TEM), or from the weight ratio obtained by decomposition analysis by strong alkali dissolution or thermal decomposition analysis method. It can also be obtained by conversion, or it can be obtained by measuring the phase volume ratio by X-ray diffraction and converting the area ratio of the cross-sectional SEM image by the sphericity of the organic polymer particles.

<Thickness>
The thickness of the resin film can be appropriately set according to the purpose of use, but is preferably in the range of, for example, 2 to 150 μm, and more preferably in the range of 10 to 120 μm. If the thickness of the resin film is less than 2 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 150 μm, the productivity of the resin film may decrease. There is.

The resin film may be in the form of a film (sheet), and may be in a state of being laminated on any base material such as a copper foil, a glass plate, a polyimide film, a polyamide film, or a polyester film.

[Metal-clad laminate]
The metal-clad laminate of the present 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, and is at least one layer of the insulating resin layer. Consists of a resin film produced by the above method. The metal-clad laminate may be a single-sided metal-clad laminate having a metal layer only on one side of the insulating resin layer, or a double-sided metal-clad laminate having metal layers on both sides of the insulating resin layer. ..

<Insulating resin layer>
The insulating resin layer is composed of a single layer or a plurality of layers, and includes a layer made of the above resin film. For example, the resin film may form a non-thermoplastic polyimide layer as a main layer of an insulating resin layer for ensuring mechanical properties and thermophysical characteristics. Further, the resin film may form a thermoplastic polyimide layer as an adhesive layer that bears an adhesive strength with a metal layer such as a copper foil. The "main layer" means a layer that occupies 50% or more of the total thickness of the insulating resin layer.

As a method for producing a metal-clad laminate having a resin film as an insulating resin layer, for example, a method of heat-pressing a metal foil directly on the resin film or via an arbitrary adhesive, a method of heat-pressing a metal foil, or a method such as metal deposition Examples thereof include a method of forming a metal layer on a film. The double-sided metal-clad laminate can be formed, for example, by forming a single-sided metal-clad laminate and then pressing the polyimide layers facing each other by heat pressing, or by applying a metal foil to the polyimide layer of the single-sided metal-clad laminate. It can be obtained by a method of crimping and forming.

<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 and these. Alloys and the like. Among these, copper or a copper alloy is particularly preferable. The metal layer may be made of a metal foil, may be metal-deposited on a film, or may be printed with a paste or the like. Further, either a metal foil or a metal plate can be used, and a copper foil or a copper plate is preferable.

The thickness of the metal layer is not particularly limited because it is appropriately set according to the purpose of use of the metal-clad laminate, but is preferably in the range of, for example, 5 μm to 3 mm, and more preferably in the range of 12 μm to 1 mm. If the thickness of the metal layer is less than 5 μm, problems such as wrinkles may occur during transportation in the manufacture of metal-clad laminates. On the contrary, if the thickness of the metal layer exceeds 3 mm, it is hard and the workability is deteriorated.

Examples will be shown below, and the features of the present invention will be described in more detail. 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.

[Measurement of viscosity]
The viscosity at 25 ° C. 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 one minute after the start of the measurement, the value when the viscosity became stable was read.

[Measurement of residual volatile components]
The amount of residual volatile components shown in each Example and Comparative Example was measured in a temperature range of 30 to 400 ° C. at 10 ° C./min using a thermogravimetric differential thermal analyzer (TG-DTA, manufactured by SII, trade name; EXSTAR6000). From the weight loss curve when the temperature was raised, the amount of weight loss from 140 ° C. to 360 ° C. was determined and used as the residual volatile content as compared with the amount of non-volatile components in the resin film.

[Measurement of melting point]
Using a differential scanning calorimetry device (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 for measurement. ..

[Measurement method of particle size]
The particle size was measured by a laser diffraction / scattering type measurement method using a laser diffraction type particle size distribution measuring device (manufactured by Malvern Co., Ltd., trade name; Master Sizer 3000).

[Measurement of true density]
The true specific gravity was measured by the pycnometer method (liquid phase substitution method) using a continuous automatic powder true density measuring device (manufactured by Seishin Enterprise Co., Ltd., trade name; AUTO TRUE DENSERMAT-7000).

[Appearance evaluation]
Visually confirmed, less than 10 spots or protrusions of 0.2 mm or more in the A4 size plane were evaluated as "good", less than 20 were evaluated as "possible", and 20 or more were evaluated as "impossible".

[Measurement of relative permittivity and dielectric loss tangent]
Using a vector network analyzer (manufactured by Agent, trade name; vector network analyzer E8633C) and an SPDR resonator, the relative permittivity (ε1) and dielectric loss tangent (Tanδ1) of the resin film (resin film after curing) at a frequency of 10 GHz were determined. It was measured. The resin film used for the measurement was left to stand for 24 hours under the conditions of temperature: 24-26 ° C. and humidity: 45-55%.

[Cross section observation]
1) Preparation of measurement sample After embedding the sample in an epoxy resin so that the observation surface (cross section in the thickness direction) of the copper-clad laminate (TD; 10 mm × MD; 10 mm) is in the MD direction, Using a rotary plate type grinding machine, a plurality of emery papers (up to # 1200), buff polishing (up to 1 μm of diamond particle paste), and chemical polishing with a chemical solution were performed to prepare a sample for measurement.
2) Observation of the measurement sample The observation surface of the measurement sample was observed at a magnification of 3,000 times using a scanning electron microscope (SEM).

The abbreviations used in Synthesis Examples, Comparative Examples, and Examples indicate the following compounds.
PMDA: pyromellitic dianhydride BPDA: 3,3', 4,4'-biphenyltetracarboxylic dianhydride BAPP: 2,2-bis [4- (4-aminophenoxy) phenyl] propane m-TB: 2,2'-dimethyl-4,4'-diaminobiphenylDMAc: N, N-dimethylacetamide filler 1: Liquid crystal polymer particles, amorphous powder, melting point (Tx): 320 ° C., true density; 1.4, median Diameter d ₅₀ ; 10 μm, d ₉₅ : 45 μm, d ₁₀₀ : 50 μm
Filler 2: Liquid crystal polymer particles, amorphous powder, melting point (Tx): 320 ° C., true density; 1.4, median diameter d ₅₀ : 5 μm, d ₉₅ : 23 _{μm, d 100} : 25 μm

(Synthesis Example 1)
13 g of m-TB (63 mmol), 6.4 g of BAPP (17 mmol) and 230 g of DMAc were placed in a 300 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 4.3 g of PMDA (20 mmol) and 20 g of BPDA (50 mmol) were added and stirred at room temperature for 18 hours to obtain polyamic acid solution 1 (viscosity; 24,000 cps).

(Synthesis Example 2)
24 g of BAPP (60 mmol) and 230 g of DMAc were placed in a 300 ml separable flask, and the mixture was stirred at room temperature under a nitrogen stream. After complete dissolution, 6.5 g of PMDA (30 mmol) and 8.7 g of BPDA (30 mmol) were added and stirred at room temperature for 18 hours to obtain polyamic acid solution 2 (viscosity; 21,000 cps).

[Example 1]
140 g of polyamic acid solution 1 and 19 g of filler 1 are mixed, and the mixture is visually stirred until a uniform solution is obtained. Resin solution 1 (viscosity; 34,000 cps, content of filler 1 with respect to non-volatile components; 50 volumes) %) Was prepared.

The resin solution 1 was applied onto a copper foil (electrolytic copper foil, thickness; 12 μm) and dried at 130 ° C. for 3 minutes to form a resin layer. After that, heat treatment was carried out stepwise from 155 ° C. to 280 ° C. for 16 minutes, and further heat treatment was continuously carried out from 280 ° C. to 380 ° C. (Tmax) for 4 minutes to complete imidization, and the copper-clad laminate 1 Was prepared. The appearance of the surface of the resin layer in the copper-clad laminate 1 was good. A photograph of the appearance of the surface of the resin layer is shown in FIG. Further, FIG. 2 shows a photograph of a cross-sectional observation of the resin layer in the copper-clad laminate 1.
The amount of the residual volatile component of the resin layer in the heat treatment process at 280 ° C. was 0.15% by weight, and the amount of the residual volatile component after the completion of the heat treatment was 0.07% by weight.
The copper foil of the copper-clad laminate 1 was removed by etching to prepare a resin film 1 (thickness; 45 μm). The relative permittivity of the resin film 1 was 3.32, and the dielectric loss tangent was 0.0024.

[Example 2]
The copper-clad laminate 2 was prepared in the same manner as in Example 1 except that the heat treatment time from 280 ° C. to 380 ° C. was set to 6 minutes. The appearance of the surface of the resin layer in the copper-clad laminate 2 was good.
The amount of the residual volatile component of the resin layer in the heat treatment process at 280 ° C. was 0.15% by weight, and the amount of the residual volatile component after the completion of the heat treatment was 0.06% by weight.
The copper foil of the copper-clad laminate 2 was removed by etching to prepare a resin film 2.

[Example 3]
The copper-clad laminate 3 was prepared in the same manner as in Example 1 except that the heat treatment time from 155 ° C. to 280 ° C. was set to 14 minutes. The appearance of the surface of the resin layer in the copper-clad laminate 3 was acceptable.
The amount of residual volatile components at 280 ° C. was 0.23% by weight, and the amount of residual volatile components after the completion of the heat treatment was 0.06% by weight. The copper foil of the copper-clad laminate 3 was removed by etching to prepare a resin film 3.

[Example 4]
140 g of polyamic acid solution 1 and 2.2 g of filler 2 were mixed and visually stirred until a uniform solution was obtained, and the resin solution 4 (viscosity; 28,000 cps, content of filler 2 with respect to non-volatile components; 10% by volume) was prepared.
A copper-clad laminate 4 was prepared in the same manner as in Example 1. The appearance of the surface of the resin layer in the copper-clad laminate 4 was good.
The amount of the residual volatile component of the resin layer in the heat treatment process at 280 ° C. was 0.35% by weight, and the amount of the residual volatile component after the completion of the heat treatment was 0.06% by weight. The copper foil of the copper-clad laminate 4 was removed by etching to prepare a resin film 4.

[Example 5]
140 g of polyamic acid solution 1, 175 g of filler 1 and 20 g of DMAc were mixed, and the mixture was visually stirred until a uniform solution was obtained, and the resin solution 5 (viscosity; 50,000 cps, containing filler 1 for non-volatile components) was contained. Rate; 90% by volume) was prepared.
A copper-clad laminate 5 was prepared in the same manner as in Example 1. The appearance of the surface of the resin layer in the copper-clad laminate 5 was good.
The amount of the residual volatile component of the resin layer in the heat treatment process at 280 ° C. was 0.10% by weight, and the amount of the residual volatile component after the completion of the heat treatment was 0.03% by weight. The copper foil of the copper-clad laminate 5 was removed by etching to prepare a resin film 5.

[Example 6]
20 g of polyamic acid solution 1, 136 g of filler 2 and 30 g of DMAc were mixed, and the mixture was visually stirred until a uniform solution was obtained, and resin solution 6 (viscosity; 55,000 cps, containing filler 2 for non-volatile components) was contained. Rate; 98% by volume) was prepared.
A copper-clad laminate 6 was prepared in the same manner as in Example 1. The appearance of the surface of the resin layer in the copper-clad laminate 6 was good.
The amount of the residual volatile component of the resin layer in the heat treatment process at 280 ° C. was 0.08% by weight, and the amount of the residual volatile component after the completion of the heat treatment was 0.02% by weight.
A resin film 6 (thickness; 70 μm) was prepared in the same manner as in Example 1. The relative permittivity of the resin film 6 was 3.19, and the dielectric loss tangent was 0.0009.

[Example 7]
40 g of polyamic acid solution 2 and 14 g of filler 2 are mixed, and the mixture is visually stirred until a uniform solution is obtained. Resin solution 7 (viscosity; 43,000 cps, content of filler 2 with respect to non-volatile components; 70 volumes) %) Was prepared.
A copper-clad laminate 7 was prepared in the same manner as in Example 1. The appearance of the surface of the resin layer in the copper-clad laminate 7 was acceptable.
The amount of the residual volatile component of the resin layer in the heat treatment process at 280 ° C. was 0.24% by weight, and the amount of the residual volatile component after the completion of the heat treatment was 0.03% by weight.
A resin film 7 was prepared in the same manner as in Example 1. The relative permittivity of the resin film 7 was 3.04, and the dielectric loss tangent was 0.0024.

(Comparative Example 1)
The copper-clad laminate 8 was prepared in the same manner as in Example 1 except that the heat treatment time from 155 ° C. to 280 ° C. was set to 13 minutes. The appearance of the surface of the resin layer in the copper-clad laminate 8 was not possible. A photograph of the appearance of the surface of the resin layer is shown in FIG.
The amount of the residual volatile component of the resin layer in the heat treatment process at 280 ° C. was 0.71% by weight, and the amount of the residual volatile component after the completion of the heat treatment was 0.06% by weight.
The copper foil of the copper-clad laminate 8 was removed by etching to prepare a resin film 8.

(Comparative Example 2)
A copper-clad laminate 9 was prepared in the same manner as in Example 1 except that the heat treatment time from 155 ° C. to 280 ° C. was set to 12 minutes. The appearance of the surface of the resin layer in the copper-clad laminate 9 was not possible.
The amount of the residual volatile component of the resin layer in the heat treatment process at 280 ° C. was 1.11% by weight, and the amount of the residual volatile component after the completion of the heat treatment was 0.07% by weight.
The copper foil of the copper-clad laminate 9 was removed by etching to prepare a resin film 9.

(Comparative Example 3)
Using the resin solution 4 of Example 4, a copper-clad laminate 10 was prepared in the same manner as in Example 1 except that the heat treatment time from 155 ° C. to 280 ° C. was 12 minutes. The appearance of the surface of the resin layer in the copper-clad laminate 10 was not possible.
The amount of the residual volatile component of the resin layer in the heat treatment process at 280 ° C. was 0.57% by weight, and the amount of the residual volatile component after the completion of the heat treatment was 0.07% by weight.
The copper foil of the copper-clad laminate 10 was removed by etching to prepare a resin film 10.

(Comparative Example 4)
Using the resin solution 7 in Example 7, a copper-clad laminate 11 was prepared in the same manner as in Example 1 except that the heat treatment time from 155 ° C. to 280 ° C. was 12 minutes. The appearance of the surface of the resin layer in the copper-clad laminate 11 was not possible.
The amount of the residual volatile component of the resin layer in the heat treatment process at 280 ° C. was 0.65% by weight, and the amount of the residual volatile component after the completion of the heat treatment was 0.05% by weight.
The copper foil of the copper-clad laminate 11 was removed by etching to prepare a resin film 11.

(Reference example 1)
The copper-clad laminate 12 was prepared in the same manner as in Example 1 except that the heat treatment from 155 ° C. to 280 ° C. was set to 13 minutes and the maximum temperature reached was set to 300 ° C. The appearance of the surface of the resin layer in the copper-clad laminate 12 was good, but the amount of residual volatile components at 280 ° C. was 0.70% by weight, and the amount of residual volatile components after the completion of heat treatment was 0.60% by weight. %Met.
The copper foil of the copper-clad laminate 12 was removed by etching to prepare a resin film 12 (thickness; 70 μm). The relative permittivity of the resin film 12 was 3.28, and the dielectric loss tangent was 0.0029.

The above results are summarized in Tables 1 and 2.

From the results of Examples 1 to 7, by controlling the amount of residual volatile components of the insulating layer at a temperature lower than the melting point of the filler (Tx-40 ° C.) to 0.5% by weight or less in the heat treatment, poor appearance occurs. It turns out that there is no such thing. Further, in Reference Example 1, since the amount of the residual volatile component of the insulating layer in the heat treatment process is not controlled, it can be seen that the residual amount of the volatile component in the insulating layer after the completion of the heat treatment is high.

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

Claims (8)

It is a method of manufacturing a resin film.
A step of preparing a resin composition containing a solvent, a soluble resin soluble in the solvent, and organic polymer particles insoluble in the solvent.
A step of heat-treating the resin composition to obtain a resin film containing the organic polymer particles in the solidified product of the soluble resin.
Including
The heat treatment is performed under the following conditions (a) and (b);
(A) When the melting point of the organic polymer particles is Tx [unit; ° C] and the maximum temperature reached by the heat treatment is Tmax [unit; ° C], the relationship of the following formula (1) is satisfied;
Tx ≦ Tmax ・ ・ ・ (1)
(B) When the temperature is Tx-40 ° C. in the process of raising the temperature to Tmax in the heat treatment, the content of the volatile component contained in the resin composition is 0 with respect to the content of the non-volatile component in the resin composition. .5% by weight or less;
A method for producing a resin film, which comprises satisfying the above conditions. The method for producing a resin film according to claim 1, wherein the soluble resin is at least one selected from polyamide, polyimide, polyester, polyether and precursors thereof. The method for producing a resin film according to claim 1 or 2, wherein the organic polymer particles are made of a liquid crystal polymer. The method for producing a resin film according to any one of claims 1 to 3, wherein the Tx is 240 ° C. or higher. The method for producing a resin film according to any one of claims 1 to 4, wherein the boiling point of the solvent is Tx or less. The method for producing a resin film according to any one of claims 1 to 5, wherein the ratio of the organic polymer particles to the non-volatile component of the resin film is in the range of 5 to 99% by volume. The method for producing a resin film according to any one of claims 1 to 6, wherein the thickness of the resin film is within the range of 2 to 150 μm. A method for manufacturing a metal-clad laminate comprising an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer.
A method for producing a metal-clad laminate, wherein at least one of the insulating resin layers is made of a resin film produced by the method according to any one of claims 1 to 7.

Images