JP2019014062A - Laminate, flexible metal-clad laminated sheet, and flexible printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfy low dielectric constant and low dielectric loss tangent in a laminate having a thermosetting resin layer and a polyimide layer, and to have heat resistance, flame retardancy and metal required for a substrate material of a flexible printed wiring board. Providing a laminate that satisfies the adhesiveness with foil, dimensional stability, etc. A laminate having a thermosetting resin layer and a polyimide layer, the thermosetting resin layer has a specific dielectric constant of 10 GHz or less, a dielectric loss tangent of 0.003 or less, and dynamic viscoelasticity. A laminate having a stored viscoelasticity at 20 ° C. obtained by measuring elasticity of 0.1 to 5.0 GPa, and the polyimide layer covering both sides of a thermosetting resin layer. A laminate in which the thickness of the laminate is 25 μm or more, the thickness of the polyimide layer on one side is 0.5 μm or more, and the ratio of the thickness of the polyimide layer to the total thickness of the laminate is 4 to 30%. A laminate in which the polyimide layer is a multilayer imide layer having a non-thermoplastic polyimide layer and a thermoplastic polyimide layer. [Selection diagram] None

Description

  The present invention relates to a laminate that can be suitably used for a high-frequency circuit board, a flexible metal-clad laminate provided with a metal foil on one or both sides thereof, and a flexible printed circuit board.

  In recent years, for the purpose of improving the information processing capability in electronic devices, the frequency of electrical signals transmitted through circuits has been increased. Along with the increase in the frequency of the electrical signal, it is desired to maintain the electrical reliability for the circuit board, and to suppress the decrease in the transmission speed of the electrical signal in the circuit and the loss of the electrical signal. In the range of 10 GHz to 10 GHz, a material having a low relative dielectric constant and dielectric loss tangent is demanded.

  A flexible metal-clad laminate (hereinafter also referred to as FCCL) used for manufacturing a circuit board is obtained by providing a metal foil on one side or both sides of a base resin film. A flexible metal-clad laminate can be produced by casting or applying a solution of a polyamic acid, which is a polyimide precursor, onto a metal foil and then imidizing the metal directly on the polyimide film by sputtering or plating. Examples thereof include a metallizing method for providing a layer and a thermal laminating method for bonding a polyimide film and a metal foil through an adhesive layer such as thermoplastic polyimide. Among them, the thermal laminating method is superior to other methods in that the thickness range of the metal foil that can be handled is wider than the casting method and the apparatus cost is lower than the metalizing method.

  In recent years, the use of lead-free solder has raised the required level of moisture-absorbing solder resistance, and the Tg (glass transition temperature) of the film in contact with the metal foil has been increased in order to cope with it. As a result, the temperature required for the thermal laminator is inevitably high. Therefore, the thermal stress applied to the material such as the base resin film and the adhesive layer is increased, and a dimensional change is likely to occur.

  By the way, polyimide is suitably used as a multilayer film used for a flexible metal-clad laminate that can be used as a high-frequency circuit board. A multilayer film in which an adhesive layer containing a thermoplastic polyimide is provided on at least one side of a non-thermoplastic polyimide film whose characteristics obtained by dynamic viscoelasticity measurement are in a specific range is known, and a non-thermoplastic polyimide film It is disclosed that a fluororesin is contained in (for example, Patent Document 1).

  Patent Document 1 discloses a polyimide laminated film having a low dielectric constant, a low dielectric loss tangent and a low moisture absorption rate that can reduce transmission loss, and a small dimensional change rate suitable for thermal lamination. With further increase in signal speed, a flexible printed wiring board (hereinafter also referred to as FPC) with a small transmission loss is required, and further reduction in the dielectric constant and low dielectric loss tangent of the substrate material is required.

  However, the dielectric loss tangent of polyimide is 0.005 (measured at 10 GHz) even if it is the smallest in Patent Document 1, for example, and although it is effective in reducing transmission loss, the conventional required characteristics of dimensional stability and heat resistance In many cases, the dielectric characteristics are a trade-off, and it is considered difficult to dramatically improve the dielectric characteristics with a single polyimide.

WO2016 / 159060 publication

  For this reason, provision of a new material is desired in preparation for the case where the speed increases further in the future. Therefore, the present inventors tried to make a composite with a material having a dielectric property superior to that of a polyimide material. As a means of compounding, various compounding methods including a method of blending different resins having excellent dielectric properties with polyimide resin and applying different resins having excellent dielectric properties on polyimide films were studied.

  And it tried to use the thermosetting resin layer whose storage elastic modulus in 20 degreeC obtained by the measurement of dynamic viscoelasticity is 5.0 GPa or less as a resin layer which provides a dielectric characteristic. Since the thermosetting resin layer exhibits so-called low elasticity, it is generally difficult to satisfy basic characteristics of the FPC board material such as a low linear expansion coefficient and excellent dimensional stability required for FPC. In addition, since the thermosetting resin layer easily transmits flame, it is generally difficult to ensure flame retardancy. For this reason, the examination which uses the said thermosetting resin layer as FPC until now was not made | formed.

  In view of the above-mentioned present situation, as a result of intensive studies, the present inventors have used a thermosetting resin having specific thermal characteristics and excellent dielectric characteristics, and polyimide on both sides of the thermosetting resin. It was found that by using a resin laminate coated with a layer, excellent dielectric properties can be realized, and at the same time, it has a low linear expansion coefficient, dimensional stability, and solder heat resistance required for FPC.

  That is, the present invention relates to the following.

  The present invention is a laminate having a thermosetting resin layer and a polyimide layer, wherein the thermosetting resin layer has a relative dielectric constant of 10 or less at 10 GHz and a dielectric loss tangent of 0.003 or less. And the storage elastic modulus in 20 degreeC obtained by the measurement of dynamic viscoelasticity is 0.1 GPa or more and 5.0 GPa or less, and the said polyimide layer has coat | covered both surfaces of the said thermosetting resin layer.

  It is preferable that the thickness of the laminate is 25 μm or more, the thickness of the polyimide layer on one side is 0.5 μm or more, and the ratio of the thickness of the polyimide layer to the total thickness of the laminate is 4% or more and 30% or less.

  The polyimide layer is preferably a multilayer polyimide layer having a non-thermoplastic polyimide layer and a thermoplastic polyimide layer.

  The multilayer polyimide layer is preferably provided such that a non-thermoplastic polyimide layer is adjacent to the thermosetting resin layer.

  It is preferable that the outermost layer of the multilayer polyimide layer is a thermoplastic polyimide layer.

  The laminated body preferably has a relative dielectric constant at 10 GHz of 3.0 or less, a dielectric loss tangent of 0.004 or less, and a linear expansion coefficient at 50 ° C. to 250 ° C. of 22 ppm or less.

  It is preferable to use a flexible metal-clad laminate in which a metal layer is further provided on at least one surface of the laminate.

  It is preferable to use a flexible printed circuit board having the metal-clad laminate.

  A laminate for use in a flexible printed circuit board, wherein the laminate has a thermosetting resin layer and a polyimide layer, and the thermosetting resin layer has a relative dielectric constant of 3.0 or less at 10 GHz. The dielectric loss tangent is 0.003 or less, and the storage elastic modulus at 20 ° C. obtained by measurement of dynamic viscoelasticity is 0.1 GPa or more and 5.0 GPa or less, and the polyimide layer is a thermosetting resin layer. It is preferable that both sides are coated.

  According to the laminated body according to the present invention, it is possible to make the transmission loss more excellent than the conventionally used flexible metal-clad laminates for a flexible metal-clad laminate in which a metal foil is arranged on the laminate. It is. For this reason, this invention is useful for a high frequency circuit board.

  The resin laminate in the present invention not only satisfies the adhesiveness to metal foils required for conventional flexible printed circuit board materials, solder heat resistance and dimensional stability, but can also achieve a significant improvement in flame retardancy.

  The laminate of the present invention has a thermosetting resin layer and a polyimide layer. The thermosetting resin layer has a relative dielectric constant at 10 GHz of 3.0 or less, a dielectric loss tangent of 0.003 or less, and a storage elastic modulus at 20 ° C. obtained by measurement of dynamic viscoelasticity of 0.00. 1 GPa or more and 5.0 GPa or less. The polyimide layer covers both sides of the thermosetting resin layer.

(Thermosetting resin layer)
The thermosetting resin layer used in the present invention has a relative dielectric constant of 10 or less at 10 GHz and a dielectric loss tangent of 0.003 or less. This greatly contributes to a reduction in FPC transmission loss. The relative permittivity and dielectric loss tangent at 10 GHz are obtained by the cavity resonator method. The reason for setting the value at 10 GHz is that the region of the electronic signal that is the high frequency region for the material used for the substrate of the printed wiring board is This is because a material that can reduce the electric signal loss at 10 GHz is useful. Since the thermosetting resin is used, the adhesion with the material to be laminated can be improved.

  The relative dielectric constant of the thermosetting resin layer thus obtained is preferably 2.5 or less, more preferably 2.3 or less. The dielectric loss tangent is preferably 0.0025 or less, more preferably 0.0015 or less.

  In addition, the thermosetting resin layer used in the present invention means a material that exhibits low elasticity (low storage elastic modulus) after curing a raw material resin. Specifically, low elasticity means that the storage elastic modulus at 20 ° C. obtained by measurement of dynamic viscoelasticity is 0.1 GPa or more and 5.0 GPa or less. Furthermore, the storage elastic modulus is preferably 4.0 GPa or less, and more preferably 3.5 GPa or less. Further, the storage elastic modulus at 20 ° C. of the thermosetting resin layer used in the present invention is not limited as long as it can be laminated, and is 0.1 GPa or more, preferably 0.5 GPa or more. The measurement of dynamic viscoelasticity is performed in a nitrogen atmosphere with DMS6100 manufactured by SII Nanotechnology, and the temperature dependence of the storage elastic modulus at 5 Hz is obtained.

  Resin having a relative dielectric constant at 10 GHz of 3.0 or less, a dielectric loss tangent of 0.003 or less, and a storage elastic modulus at 20 ° C. of 5.0 GPa or less obtained by measurement of dynamic viscoelasticity. As a structure having a long-chain hydrocarbon group having a hydrophobic effect or a structure having no polarity that impairs dielectric properties, for example, SF resin manufactured by Hitachi Chemical Co., Ltd., Adfrema (registered trademark) manufactured by NAMICS Co., Ltd., etc. For example, polytetrafluoroethylene (hereinafter referred to as PTFE), liquid crystal polymer (hereinafter referred to as LCP), or the like may be used as a structure having no polarity that impairs dielectric properties.

  Resin having a relative dielectric constant at 10 GHz of 3.0 or less, a dielectric loss tangent of 0.003 or less, and a storage elastic modulus at 20 ° C. of 5.0 GPa or less obtained by measurement of dynamic viscoelasticity. As, it is preferable to use SF resin manufactured by Hitachi Chemical Co., Ltd. because of its excellent heat resistance and excellent adhesion to the adjacent polyimide.

  In the laminate of the present invention, both surfaces of the thermosetting resin layer are covered with a polyimide layer. In order to exhibit excellent dielectric properties, the thickness of the thermosetting resin layer is substantially sufficiently thick compared to the polyimide layer covering both surfaces.

  As described above, the storage elastic modulus at 20 ° C. of the thermosetting resin layer in the present invention is 0.1 GPa or more and 5.0 GPa or less, and the dimensional stability is also low. Therefore, it is considered that the basic characteristics of the FPC board material of the thermosetting resin layer deteriorate as described above. However, when the present inventors confirmed these basic characteristics, surprisingly good results were obtained that sufficiently satisfied the dimensional stability and heat resistance required for conventional flexible printed circuit board materials. This is presumably because the storage modulus of the polyimide layer at 20 ° C. is about 6.0 GPa or more, and the dimensional stability is maintained by having the polyimide layers on both sides of the thermosetting resin layer.

  Moreover, despite the large proportion of the thermosetting resin layer in the laminate, the excellent flame retardancy of the polyimide is utilized by the configuration of the present invention, and the laminate also has excellent flame retardancy. . This is presumably because both surfaces of the thermosetting resin layer are covered with polyimide resin, so that transmission to the central portion is prevented even when the flame approaches.

  The type of polyimide used for the polyimide layers on both sides of the thermosetting resin layer may be the same or different, but from the viewpoint of maintaining the uniformity of linear expansion and suppressing the warpage of the resin laminate, Preferably they are the same.

  In the present invention, the thickness of the resin laminate is preferably 25 μm or more, more preferably 50 μm or more, and a preferable upper limit is 100 μm or less. The thickness of the single-sided polyimide layer is preferably 0.5 μm or more and more preferably 1 μm or more from the viewpoint of ensuring flame retardancy. From the viewpoint of obtaining excellent dielectric properties, the ratio of the thickness of the polyimide layer to the thickness of the entire laminate is preferably 30% or less, and more preferably 25% or less.

  Moreover, it is preferable that the thickness of the polyimide layer of both surfaces is the same, it is preferable that the thickness of the polyimide layer of both surfaces is 0.5 micrometer or more, respectively, and 1 micrometer or more is more preferable each. The ratio of the thickness of the polyimide layer (the thickness of the polyimide layers on both sides) to the thickness of the entire laminate is preferably 4% or more, and more preferably 5% or more.

  From the above, the thickness of the laminate is 25 μm or more, the thickness of the polyimide layer on one side is 0.5 μm or more, and the ratio of the thickness of the polyimide layer to the total thickness of the laminate is preferably 4% or more, and 30% or less. It is preferable that When the relationship between the thickness of the thermosetting resin layer and the polyimide layer is within this range, the characteristics and flame retardancy as an FPC board material are good without causing deterioration of the dielectric characteristics.

  The laminate of the present invention can have a relative dielectric constant of 3.0 or less and a dielectric loss tangent of 0.004 or less. The relative dielectric constant of the laminate is more preferably 2.8 or less, and particularly preferably 2.5 or less. The dielectric loss tangent is preferably 0.0035 or less, and more preferably 0.003 or less. The linear expansion coefficient is preferably 22 ppm or less, and more preferably 20 ppm or less. The FPC obtained as described above not only has excellent electrical characteristics, but also has excellent characteristics as an FPC such as a low linear expansion coefficient and excellent dimensional stability.

(Polyimide layer)
The polyimide layer used in the present invention is preferably a multilayer polyimide layer comprising a non-thermoplastic polyimide layer and a thermoplastic polyimide layer. The multilayer polyimide layer is preferably provided so that the non-thermoplastic polyimide layer is adjacent to the thermosetting resin layer. That is, the structure is preferably thermoplastic polyimide layer / non-thermoplastic polyimide layer / thermosetting resin layer / non-thermoplastic polyimide layer / thermoplastic polyimide layer.

  Hereinafter, the raw material monomer of the polyamic acid which is a precursor of the non-thermoplastic polyimide used for the non-thermoplastic polyimide layer, the production of the polyamic acid of the precursor of the non-thermoplastic polyimide, the method for producing the non-thermoplastic polyimide film, heat This will be described in detail in the order of the plastic polyimide layer.

(Raw material monomer of polyamic acid which is a precursor of non-thermoplastic polyimide)
The raw material monomer of polyamic acid which is a precursor of non-thermoplastic polyimide in the present invention is a non-thermoplastic polyimide obtained by imidizing polyamic acid which is a precursor, solder heat resistance and dimensional stability required for conventional flexible printed circuit board materials If it is controlled by the primary structure and the manufacturing method, it is not particularly limited. Diamines and acid dianhydrides commonly used in the synthesis of polyamic acids can be used.

  The aromatic diamine is not particularly limited as long as the effects of the present invention can be exhibited, but 2,2′-bis [4- (4-aminophenoxy) phenyl] propane, 4,4′-diaminodiphenylpropane, 4,4′- Diaminodiphenylmethane, 4,4′-diaminodiphenylsulfide, 3,3′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfone, 4,4′-oxydianiline, 3,3′-oxydianiline, 3, 4'-oxydianiline, 4,4'-diaminodiphenyldiethylsilane, 4,4'-diaminodiphenylsilane, 4,4'-diaminodiphenylethylphosphine oxide, 4,4'-diaminodiphenyl N-methylamine, 4 , 4′-Diaminodiphenyl N-phenylamine, 1,4-diaminobenzene (p-ph Nylenediamine), bis {4- (4-aminophenoxy) phenyl} sulfone, bis {4- (3-aminophenoxy) phenyl} sulfone, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′- Bis (3-aminophenoxy) biphenyl, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 3,3′-diaminobenzophenone, 4,4′-diaminobenzophenone 2,2-bis (4-aminophenoxyphenyl) propane and the like, and these can be used alone or in combination.

  In addition, the acid dianhydride compound that can be used as a raw material monomer for the polyamic acid is not particularly limited as long as the effects of the present invention can be exhibited, but pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid Dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetra Carboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 4,4′-oxyphthalic acid Anhydride, 3,4'-oxyphthalic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propanoic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, Bi (3,4-dicarboxyphenyl) propanoic dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane Anhydride, bis (2,3-dicarboxyphenyl) methanoic dianhydride, bis (3,4-dicarboxyphenyl) ethanoic dianhydride, oxydiphthalic dianhydride, bis (3,4-dicarboxyphenyl) ) Sulfonic acid dianhydride, p-phenylenebis (trimellitic acid monoester acid anhydride), ethylene bis (trimellitic acid monoester acid anhydride), bisphenol A bis (trimellitic acid monoester acid anhydride) and the like And the like.

(Production of polyamic acid which is a precursor of non-thermoplastic polyimide)
Any organic solvent can be used as long as it dissolves the non-thermoplastic polyamic acid as the organic solvent used in the production of the polyamic acid which is a precursor of the non-thermoplastic polyimide. For example, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and the like are preferable, and N, N-dimethylformamide and N, N-dimethylacetamide can be more preferably used. . The solid content concentration of the polyamic acid which is the precursor of the non-thermoplastic polyimide is not particularly limited, and the non-thermoplastic polyimide film has sufficient mechanical strength when it is in the range of 5 wt% to 35 wt%. Polyamic acid which is a precursor of thermoplastic polyimide is obtained.

  The order of addition of the aromatic diamine and aromatic dianhydride as raw materials is not particularly limited, but the characteristics of the resulting non-thermoplastic polyimide are controlled not only by the chemical structure of the raw materials but also by controlling the order of addition. Is possible.

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

(Method for producing non-thermoplastic polyimide film)
In order to obtain a non-thermoplastic polyimide film in the present invention, the following steps i) a polyamic acid solution (hereinafter referred to as a precursor of a non-thermoplastic polyimide) by reacting an aromatic diamine with an aromatic dianhydride in an organic solvent , Also referred to as non-thermoplastic polyamic acid),
ii) casting a film-forming dope containing the non-thermoplastic polyamic acid solution from a die onto a support to form a resin layer (sometimes referred to as a liquid film);
iii) a step of peeling the gel film from the support after the resin layer is heated on the support to obtain a self-supporting gel film,
iv) further heating, imidizing the remaining amic acid and drying to obtain a non-thermoplastic polyimide film;
It is preferable to contain.

  ii) Subsequent steps are roughly divided into a thermal imidization method and a chemical imidization method. The thermal imidization method is a method in which a polyamic acid solution is cast as a film-forming dope without using a dehydrating ring-closing agent or the like, and imidation is advanced only by heating. One chemical imidization method is a method of promoting imidization by using, as a film-forming dope, a polyamic acid solution to which at least one of a dehydrating cyclization agent and a catalyst is added as an imidization accelerator. Either method may be used, but the chemical imidation method is superior in productivity.

  As the dehydrating ring-closing agent, acid anhydrides typified by acetic anhydride can be suitably used. As the catalyst, tertiary amines such as aliphatic tertiary amines, aromatic tertiary amines, and heterocyclic tertiary amines can be suitably used.

  As the support for casting the film-forming dope, a glass plate, aluminum foil, endless stainless steel belt, stainless steel drum or the like can be suitably used. The heating conditions are set according to the thickness of the finally obtained film and the production rate, and after at least one of imidization or drying is partially performed, the film is peeled off from the support and is called a polyamic acid film (hereinafter referred to as a gel film). )

  Fix the end of the gel film and dry to avoid shrinkage during curing, remove water, residual solvent, imidization accelerator from the gel film, and completely imidize the remaining amic acid, A film containing polyimide is obtained. About a heating condition, what is necessary is just to set suitably according to the thickness and production rate of the film finally obtained.

(Thermoplastic polyimide layer)
The thermoplastic polyimide contained in the thermoplastic polyimide layer in the present invention is obtained by imidizing polyamic acid as a precursor.

  FPC uses, for example, an insulating film layer such as polyimide as a core film, and a flexible metal-clad laminate bonded to the surface of the core film by heating and pressure bonding a metal foil layer through an adhesive layer made of various adhesive materials. It is obtained by manufacturing on a plate and further forming a circuit pattern. Conventionally, an epoxy resin or an acrylic resin has been used for the adhesive layer, but these have poor heat resistance, and use applications are limited. However, a two-layer flexible printed wiring board (hereinafter also referred to as a two-layer FPC) using thermoplastic polyimide as an adhesive layer is expected to further increase demand because of its excellent heat resistance and flexibility.

  The aromatic diamine and aromatic tetracarboxylic dianhydride used in the polyamic acid which is a precursor of the thermoplastic polyimide used in the present invention may be the same as those used in the non-thermoplastic polyimide layer. In order to obtain a thermoplastic polyimide film, it is preferable to react a flexible diamine with an acid dianhydride. Examples of flexible diamines include 4,4′-diaminodiphenyl ether, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 2,2-bis (4-aminophenoxyphenyl) propane and the like can be mentioned. Examples of acid dianhydrides that can be suitably combined with these diamines include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4, 4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, etc. are mentioned.

The method for producing a thermoplastic polyamic acid in the present invention is a thermoplastic polyimide obtained by imidizing the obtained polyamic acid, adhesion with a metal foil required for conventional flexible printed circuit board materials, solder heat resistance, dimensional stability, Any known method can be used as long as it has flame retardancy. For example, the following steps (Aa) to (Ac):
(Aa) a step of reacting an aromatic diamine and an aromatic dianhydride in an organic solvent in an excess of aromatic diamine to obtain a prepolymer having amino groups at both ends;
(Ab) a step of additionally adding an aromatic diamine having a structure different from that used in the step (Aa),
(Ac) Further, the aromatic dianhydride having a structure different from that used in the step (Aa) is substantially equal to the aromatic diamine and aromatic dianhydride in all steps. Adding and polymerizing so that
Can be manufactured by.

Alternatively, the following steps (Ba) to (Bc):
(Ba) An aromatic diamine and an aromatic acid dianhydride are reacted in an organic polar solvent in an excess of aromatic acid dianhydride, and a prepolymer having acid anhydride groups at both ends is obtained. Obtaining step,
(Bb) a step of additionally adding an aromatic dianhydride having a structure different from that used in the step (Ba),
(Bc) Furthermore, the aromatic diamine having a different structure from that used in the step (Ba) is used so that the aromatic diamine and the aromatic dianhydride are substantially equimolar in all steps. Adding and polymerizing,
It is also possible to obtain polyamic acid by going through.

(Solid content concentration of polyamic acid)
The solid content concentration of the polyamic acid of the present invention is not particularly limited, and it is usually 5% to 35% by weight, preferably 10% to 30% by weight. When the concentration is in this range, an appropriate molecular weight and solution viscosity are obtained.

(Method for producing a laminate having a thermosetting resin layer and a polyimide layer)
The manufacturing method of the laminated body which has a thermosetting resin layer and a polyimide layer in this invention is explained in full detail. The method for producing a laminate in the present invention includes, for example, synthesizing a non-thermoplastic polyamic acid in i), and then proceeding to steps ii) to iv), and then recovering the non-thermoplastic polyimide film once recovered from the thermosetting resin film Are laminated while curing the thermosetting resin by thermocompression bonding or the like. Then, when providing a thermoplastic polyimide layer, it is also possible to provide this layer by coating.

  When a thermoplastic polyimide layer is provided by coating, a thermoplastic polyamic acid may be applied and then imidized, or a thermoplastic polyimide solution that can form a thermoplastic polyimide layer is applied and dried. Also good. FCCL can be manufactured by providing a metal layer in the laminated body obtained in this way.

  A flexible metal-clad laminate processed into a two-layer FPC can be manufactured by laminating with a metal foil using the laminate of the present invention. As a means for forming the laminate on the metal foil, after obtaining the laminate as described above, there is a means for obtaining a flexible metal-clad laminate by bonding the metal foil by heating and pressing (thermal lamination method). It is done. The means and conditions for bonding the metal foil may be appropriately selected from conventionally known ones.

  The metal foil is not particularly limited, and any metal foil can be used. For example, copper, stainless steel, nickel, aluminum, and alloys of these metals can be suitably used. In general metal-clad laminates, copper such as rolled copper and electrolytic copper is frequently used, but can be preferably used in the present invention.

  Moreover, the said metal foil can select what has various characteristics, such as surface treatment and surface roughness, according to the objective. Furthermore, a rust inhibitor, a heat treatment agent, or an adhesive may be applied to the surface of the metal foil. The thickness of the metal foil is not particularly limited, and may be any thickness that can exhibit a sufficient function depending on the application. FPC can be obtained by etching the metal layer of FCCL thus obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited only to these Examples. In addition, the evaluation methods of the relative dielectric constant, dielectric loss tangent, linear expansion coefficient, flame retardancy, flexible metal foil laminate peel strength, hygroscopic solder heat resistance, dimensional change rate of the laminates in the synthesis examples, examples and comparative examples are It is as follows.

<Measurement of relative dielectric constant and dielectric loss tangent>
The dielectric constant and dielectric loss tangent were measured using a network analyzer 8719C manufactured by HEWLETTPACKARD and a cavity resonator vibration method dielectric constant measuring apparatus CP511 manufactured by Kanto Electronics Co., Ltd. Samples were cut into 2 mm × 100 mm and 23 ° C./50% R.D. H. Measurements were made after humidity conditioning for 24 hours in the environment. The measurement was performed at 10 GHz.

<Water absorption rate>
The laminate cut out to 50 mm × 50 mm was dried at 150 ° C. for 30 minutes, and the weight (w1) in an absolutely dry state was measured, and then immersed in water. After 24 hours, the test piece was taken out of the water, the surface moisture was wiped off, and the weight (w2) was measured. The water absorption was calculated from the formula (1) using the obtained w1 and w2.

  Water absorption (%) = {(w2-w1) / w1} × 100 Formula (1)

<Measurement of linear expansion coefficient (CTE)>
The linear expansion coefficient was increased from −10 ° C. to 300 ° C. at 10 ° C./min using a thermomechanical analyzer manufactured by SII Nanotechnoguchi Ji Co., Ltd., trade name: TMA / SS6100, and then increased to −10 ° C. to 40 ° C. The temperature was further increased at 10 ° C./min, and a value of 50 to 250 ° C. at the second temperature increase was estimated. The measurement conditions are shown below.
Sample shape: width 3mm, length 10mm
Load: 1g
Measurement temperature range: -10 ° C to 300 ° C
Atmosphere: Under air atmosphere

<Flame retardance>
A test piece based on the UL-94 standard was prepared using a laminate cut out to 200 mm × 50 mm, and a combustion test was performed based on the VTM test. The case where it passed the judgment standard of VTM-0 was set to (good), and the case where it failed was set to x (bad).

<Peel strength>
The peel strength was measured when the 1 mm metal wiring pattern formed on the double-sided flexible metal-clad laminate obtained in Examples and Comparative Examples was peeled at 90 degrees. The peel strength was evaluated according to JISC-6471.

<Hygroscopic solder heat resistance>
The double-sided flexible metal-clad laminates obtained in the examples and comparative examples were cut into 3.5 cm squares, and one side (for convenience, the A side) had a 2.5 cm square copper foil layer left in the center of the sample. On the opposite side (for convenience, B side), five samples were prepared by removing the excess copper foil layer by etching treatment so that the copper foil layer remained on the entire surface. The obtained samples were 85 ° C. and 85% R.D. H. The sample was left for 72 hours under the humidification conditions, and a moisture absorption treatment was performed. After the moisture absorption treatment, each sample was immersed in a 300 ° C. solder bath for 10 seconds. If the copper foil layer on the B side is completely removed by etching on the sample after solder immersion and there is no change in the appearance of the part where the copper foil overlaps in all five samples, ○ (good), 5 samples If one or more of the samples were confirmed to be whitened, swollen, or peeled off from the copper foil, it was evaluated as x (bad).

<Measurement of dimensional change rate>
Based on JISC6481, four holes were formed in the flexible metal-clad laminate, and the distance of each hole was measured. Next, after carrying out an etching process to remove the metal foil from the flexible metal-clad laminate, 23 ° C./55% R.D. H. Left in a constant temperature room for 24 hours. Then, each distance was measured about the said four holes similarly to the etching process front. The measured value of the distance of each hole before removing the metal foil was set as D1, and the measured value of the distance of each hole after removing the metal foil was set as D2, and the dimensional change rate before and after etching was obtained by the following equation (2). In addition, the said dimensional change rate was measured about both MD direction (film conveyance direction) and TD direction (direction orthogonal to a film conveyance direction).

  Dimensional change rate (%) = {(D2−D1) / D1} × 100 (2)

<Measurement of dynamic viscoelasticity>
Measurement was performed in a temperature range of −50 to 450 ° C. using a DMS6100 manufactured by SII Nanotechnology (sample size: width 9 mm, length 40 mm) at a frequency of 5 Hz and a temperature rising rate of 3 ° C./min. The storage modulus at 20 ° C. was estimated from a curve plotting storage modulus against temperature.

<Synthesis of non-thermoplastic polyimide precursor>
(Synthesis Example 1)
In a glass flask having a capacity of 2000 ml, 657.8 g of N, N-dimethylformamide (hereinafter also referred to as DMF), 10.5 g of diaminodiphenyl ether (hereinafter also referred to as ODA) and 2,2-bis [4- (4- 32.4 g of aminophenoxy) phenyl] propane (hereinafter also referred to as BAPP) was added, and 17.0 g of benzophenone tetracarboxylic dianhydride (hereinafter also referred to as BTDA) and pyromellitic acid 2 were stirred under a nitrogen atmosphere. 14.3 g of anhydride (hereinafter also referred to as PMDA) was gradually added. After visually confirming that BTDA and PMDA were dissolved, 14.2 g of p-phenylenediamine (hereinafter also referred to as PDA) was added and stirred for 5 minutes. Subsequently, 28.7 g of PMDA was added and stirred for 30 minutes. Finally, a solution in which 1.7 g of PMDA is dissolved in DMF so as to have a solid content concentration of 7.2% is prepared, and this solution is gradually added to the reaction solution while paying attention to increase in viscosity. When the viscosity at 23 ° C. reached 2000 poise, the addition and stirring were stopped to obtain a polyamic acid solution.

(Synthesis Example 2)
While adding 625.9 g of DMF and 23.45 g of PDA to a glass flask having a capacity of 2000 ml and stirring in a nitrogen atmosphere, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (hereinafter referred to as BPDA). (57.4 g) was gradually added. After visually confirming that BPDA was dissolved, 17.1 g of 4,4′-bis (4-aminophenoxy) biphenyl (hereinafter also referred to as BAPB) and 19.0 g of BAPP were added and stirred under a nitrogen atmosphere. 6.4 g of BPDA was gradually added. After visually confirming that BPDA was dissolved, 14.4 g of 4,4′-oxydiphthalic anhydride (hereinafter also referred to as ODPA) and 8.1 g of PMDA were added and stirred for 30 minutes, and then 116 g of PTFE particles were added. The mixture was further stirred for 30 minutes. After stirring, a solution in which 1.7 g of PMDA was dissolved in DMF to a solid content concentration of 7.2% was prepared, and this solution was gradually added to the above reaction solution while paying attention to increase in viscosity. When the viscosity at 23 ° C. reached 2000 poise, the addition and stirring were stopped to obtain a polyamic acid solution.

<Synthesis of thermoplastic polyimide precursor>
(Synthesis Example 3)
While maintaining the inside of the reaction system at 20 ° C., 43.6 g of BAPP was added to 323.0 g of DMF, and while stirring under a nitrogen atmosphere, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride ( 43.6 g) (hereinafter also referred to as BPDA) was gradually added. After visually confirming that BPDA was dissolved, 19.0 g of PMDA was added and stirred for 30 minutes. A solution prepared by dissolving 0.7 g of PMDA in DMF so that the solid content concentration is 7.2% is prepared, and this solution is gradually added to the above reaction solution while paying attention to increase in viscosity, so that the viscosity becomes 800 poise. The polymerization was terminated when reached.

<Production of laminate>
Example 1
An imidization accelerator comprising acetic anhydride / isoquinoline / DMF (weight ratio 7.2 / 2.2 / 10.6) was added to the polyamic acid solution obtained in Synthesis Example 2 at a weight ratio of 50% with respect to the polyamic acid solution. The mixture was added, continuously stirred by a mixer, extruded from a T-die, and cast on a stainless steel endless belt. The resin film is heated at 120 ° C. for 60 seconds, and then the self-supporting gel film is peeled off from the endless belt and fixed to the tenter clip. At 250 ° C. for 8 seconds, 350 ° C. for 8 seconds, 400 ° C. for 60 seconds. Drying and imidization were performed to obtain a polyimide film having a thickness of 4 μm. The obtained polyimide film was thermocompression bonded under conditions of 185 ° C., 2.0 MPa, 90 min through both sides of a 38 μm SF resin (product name: AS-8000) film manufactured by Hitachi Chemical Co., Ltd. The polyamic acid solution obtained in Synthesis Example 3 was applied to both sides of the film so that the final thickness on one side was 3.0 μm and dried at 120 ° C. for 120 seconds. Subsequently, imidization was performed by heating at 350 ° C. for 11 seconds to obtain a laminate having a total thickness of 52 μm. Using the obtained laminate, the dielectric constant, dielectric loss tangent, water absorption, flame retardancy, and CTE were evaluated.

  Furthermore, 12 μm electrolytic copper foil (3EC-M3S-HTE, manufactured by Mitsui Metals) is arranged on both sides of the obtained laminate, and a protective film (Apical 125 NPI; manufactured by Kaneka) is further used on both sides of the copper foil. Thermal lamination was performed under the conditions of 360 ° C., laminating pressure of 265 N / cm (27 kgf / cm), laminating speed of 1.0 m / min, and the peel strength, hygroscopic solder heat resistance and dimensional change rate of the obtained flexible metal-clad laminate were determined. evaluated. The results are shown in Table 1.

(Example 2)
Using the polyamic acid solution obtained in Synthesis Example 2, a 4 μm-thick polyimide film obtained by the same method as the production of the polyimide film used in Example 1 was replaced with 28 μm SF resin (product name) : AS-400HS) After thermocompression bonding under conditions of 185 ° C., 2.0 MPa, 90 min through both surfaces of the film, the polyamic acid solution obtained in Synthesis Example 3 was applied to both surfaces of the obtained laminate. Was applied to a thickness of 2.0 μm and dried at 120 ° C. for 120 seconds. Subsequently, imidization was performed by heating at 350 ° C. for 11 seconds to obtain a laminate having a total thickness of 40 μm. Using the obtained laminate, the dielectric constant, dielectric loss tangent, water absorption, flame retardancy, and CTE were evaluated.

  Furthermore, heat lamination was performed on both surfaces of the obtained laminate under the same conditions as in Example 1, and the peel strength, moisture-absorbing solder heat resistance, and dimensional change rate of the obtained flexible metal-clad laminate were evaluated. The results are shown in Table 1.

(Example 3)
An imidization accelerator composed of acetic anhydride / isoquinoline / DMF (weight ratio 7.2 / 2.2 / 10.6) was added to the polyamic acid solution obtained in Synthesis Example 1 at a weight ratio of 50% with respect to the polyamic acid solution. The mixture was added, continuously stirred by a mixer, extruded from a T-die, and cast on a stainless steel endless belt. The resin film is heated at 120 ° C. for 60 seconds, and then the self-supporting gel film is peeled off from the endless belt and fixed to the tenter clip. At 250 ° C. for 8 seconds, 350 ° C. for 8 seconds, 400 ° C. for 60 seconds. Drying and imidization were performed to obtain a polyimide film having a thickness of 3 μm. The obtained polyimide film was thermocompression bonded under conditions of 185 ° C., 2.0 MPa, and 90 min through both surfaces of a 40 μm SF resin (product name: AS-8000) film manufactured by Hitachi Chemical Co., Ltd. The polyamic acid solution obtained in Synthesis Example 3 was applied to both sides of the film so that the final thickness on one side was 3.0 μm and dried at 120 ° C. for 120 seconds. Subsequently, imidization was performed by heating at 350 ° C. for 11 seconds to obtain a laminate having a total thickness of 52 μm. Using the obtained laminate, the relative dielectric constant, dielectric loss tangent, water absorption, flame retardancy, and coefficient of linear expansion (CTE) were evaluated.

  Furthermore, 12 μm electrolytic copper foil (3EC-M3S-HTE, manufactured by Mitsui Metals) is arranged on both sides of the obtained laminate, and a protective film (Apical 125 NPI; manufactured by Kaneka) is further used on both sides of the copper foil. Thermal lamination was performed under the conditions of 360 ° C., laminating pressure of 265 N / cm (27 kgf / cm), laminating speed of 1.0 m / min, and the peel strength, hygroscopic solder heat resistance and dimensional change rate of the obtained flexible metal-clad laminate were determined. evaluated. The results are shown in Table 1.

(Example 4)
Using the polyamic acid solution obtained in Synthesis Example 1, a 3 μm-thick polyimide film obtained by the same method as the production of the polyimide film used in Example 3 was replaced with a 38 μm SF resin (product name) : AS-400HS) After thermocompression bonding under conditions of 185 ° C., 2.0 MPa, 90 min through both surfaces of the film, the polyamic acid solution obtained in Synthesis Example 3 was applied to both surfaces of the obtained laminate. Was 3.0 μm, and dried at 120 ° C. for 120 seconds. Subsequently, imidization was performed by heating at 350 ° C. for 11 seconds to obtain a laminate having a total thickness of 50 μm. Using the obtained laminate, the dielectric constant, dielectric loss tangent, water absorption, flame retardancy, and CTE were evaluated.

  Furthermore, heat lamination was performed on both surfaces of the obtained laminate under the same conditions as in Example 1, and the peel strength, moisture-absorbing solder heat resistance, and dimensional change rate of the obtained flexible metal-clad laminate were evaluated. The results are shown in Table 1.

(Comparative Example 1)
An imidization accelerator composed of acetic anhydride / isoquinoline / DMF (weight ratio 7.2 / 2.2 / 10.6) was added to the polyamic acid solution obtained in Synthesis Example 1 at a weight ratio of 50% with respect to the polyamic acid solution. The mixture was added, continuously stirred by a mixer, extruded from a T-die, and cast on a stainless steel endless belt. This resin film is heated at 120 ° C. for 120 seconds, and then the self-supporting gel film is peeled off from the endless belt and fixed to the tenter clip. At 250 ° C. for 11 seconds, 350 ° C. for 11 seconds, 450 ° C. for 120 seconds. Drying and imidization were performed to obtain a polyimide film having a thickness of 17 μm. Both surfaces of the polyimide film were prepared by using an SF resin (product name: SFR-2300MR) manufactured by Hitachi Chemical Co., Ltd. diluted with toluene so that the solid content concentration was 20%. And dried at 110 ° C. for 600 seconds. Subsequently, heat curing was performed at 185 ° C. for 60 minutes to obtain a laminate having a total thickness of 25 μm. Using the obtained laminate, the dielectric constant, dielectric loss tangent, water absorption, flame retardancy, and CTE were evaluated.

  Furthermore, 12 μm electrolytic copper foil (3EC-M3S-HTE, manufactured by Mitsui Metals) is arranged on both sides of the obtained laminate, and a protective film (Apical 125 NPI; manufactured by Kaneka) is further used on both sides of the copper foil. When heat lamination was performed under the conditions of 360 ° C., laminating pressure of 265 N / cm (27 kgf / cm), and laminating speed of 1.0 m / min, the resin layer in the laminate flowed to obtain a suitable flexible metal-clad laminate. I couldn't.

(Comparative Example 2)
Hitachi Chemical Co., Ltd. having a thickness of 6.5 μm on both sides of a polyimide film having a thickness of 12.5 μm obtained by the same method as the production of the polyimide film used in Comparative Example 1 using the polyamic acid solution obtained in Synthesis Example 1. A company-made SF resin (product name: AS-8000) film was thermocompression bonded at 70 ° C. and 0.4 MPa to obtain a laminate having a total thickness of 25.5 μm. Using the obtained laminate, the dielectric constant, dielectric loss tangent, water absorption, flame retardancy, and CTE were evaluated.

  Furthermore, 12 μm electrolytic copper foil (3EC-M3S-HTE, manufactured by Mitsui Metals) is arranged on both sides of the obtained laminate, and a protective film (Apical 125 NPI; manufactured by Kaneka) is further used on both sides of the copper foil. When heat lamination was performed under the conditions of 360 ° C., laminating pressure of 265 N / cm (27 kgf / cm), and laminating speed of 1.0 m / min, the resin layer in the laminate flowed to obtain a suitable flexible metal-clad laminate. I couldn't.

(Comparative Example 3)
Hitachi Chemical Co., Ltd. having a thickness of 6.5 μm on both sides of a polyimide film having a thickness of 17.0 μm obtained by the same method as the production of the polyimide film used in Comparative Example 1, using the polyamic acid solution obtained in Synthesis Example 1. A company-made SF resin (product name: AS-8000) film was thermocompression bonded at 70 ° C. and 0.4 MPa to obtain a laminate having a total thickness of 30 μm. Using the obtained laminate, the dielectric constant, dielectric loss tangent, water absorption, flame retardancy, and CTE were evaluated.

  Furthermore, 12 μm electrolytic copper foil (3EC-M3S-HTE, manufactured by Mitsui Metals) is arranged on both sides of the obtained laminate, and a protective film (Apical 125 NPI; manufactured by Kaneka) is further used on both sides of the copper foil. When heat lamination was performed under the conditions of 360 ° C., laminating pressure of 265 N / cm (27 kgf / cm), and laminating speed of 1.0 m / min, the resin layer in the laminate flowed to obtain a suitable flexible metal-clad laminate. I couldn't.

(Comparative Example 4)
Using the polyamic acid solution obtained in Synthesis Example 1, a polyimide film having a thickness of 13 μm on both sides of a 17.0 μm-thick polyimide film obtained by the same method as the production of the polyimide film used in Comparative Example 1 was manufactured. An SF resin (product name: AS-8000) film was thermocompression bonded at 70 ° C. and 0.4 MPa to obtain a laminate having a total thickness of 43 μm. Using the obtained laminate, the dielectric constant, dielectric loss tangent, water absorption, flame retardancy, and CTE were evaluated.

  Furthermore, 12 μm electrolytic copper foil (3EC-M3S-HTE, manufactured by Mitsui Metals) is arranged on both sides of the obtained laminate, and a protective film (Apical 125 NPI; manufactured by Kaneka) is further used on both sides of the copper foil. When heat lamination was performed under the conditions of 360 ° C., laminating pressure of 265 N / cm (27 kgf / cm), and laminating speed of 1.0 m / min, the resin layer in the laminate flowed to obtain a suitable flexible metal-clad laminate. I couldn't.

(Comparative Example 5)
An imidization accelerator composed of acetic anhydride / isoquinoline / DMF (weight ratio 7.2 / 2.2 / 10.6) was added to the polyamic acid solution obtained in Synthesis Example 2 at a weight ratio of 50% with respect to the polyamic acid solution. The mixture was added, continuously stirred by a mixer, extruded from a T-die, and cast on a stainless steel endless belt. The resin film is heated at 120 ° C. for 120 seconds, and then the self-supporting gel film is peeled off from the endless belt and fixed to the tenter clip. At 250 ° C. for 25 seconds, 350 ° C. for 20 seconds, and 400 ° C. for 200 seconds. It dried and imidated and obtained the 44-micrometer-thick polyimide film. The polyamic acid solution obtained in Synthesis Example 3 was applied to both sides of the obtained polyimide film so that the final single-sided thickness was 3.0 μm, and dried at 120 ° C. for 120 seconds. Subsequently, imidization was performed by heating at 350 ° C. for 11 seconds to obtain a laminate having a total thickness of 50 μm. Using the obtained laminate, the dielectric constant, dielectric loss tangent, water absorption, flame retardancy, and CTE were evaluated.

  Furthermore, 12 μm electrolytic copper foil (3EC-M3S-HTE, manufactured by Mitsui Metals) is arranged on both sides of the obtained laminate, and a protective film (Apical 125 NPI; manufactured by Kaneka) is further used on both sides of the copper foil. Thermal lamination was performed under the conditions of 360 ° C., laminating pressure of 265 N / cm (27 kgf / cm), laminating speed of 1.0 m / min, and the peel strength, hygroscopic solder heat resistance and dimensional change rate of the obtained flexible metal-clad laminate were determined. evaluated. The results are shown in Table 1.

(Comparative Example 6)
An imidization accelerator composed of acetic anhydride / isoquinoline / DMF (weight ratio 7.2 / 2.2 / 10.6) was added to the polyamic acid solution obtained in Synthesis Example 2 at a weight ratio of 50% with respect to the polyamic acid solution. The mixture was added, continuously stirred by a mixer, extruded from a T-die, and cast on a stainless steel endless belt. The resin film is heated at 120 ° C. × 240 seconds, and then the self-supporting gel film is peeled off from the endless belt and fixed to the tenter clip. At 250 ° C. × 22 seconds, 350 ° C. × 35 seconds, 400 ° C. × 240 seconds. Drying and imidization were performed to obtain a polyimide film having a thickness of 34 μm. The polyamic acid solution obtained in Synthesis Example 3 was applied to both sides of the obtained polyimide film so that the final single-sided thickness was 8.0 μm, and dried at 120 ° C. for 240 seconds. Subsequently, imidization was performed by heating at 350 ° C. for 25 seconds to obtain a laminate having a total thickness of 50 μm. Using the obtained laminate, the dielectric constant, dielectric loss tangent, water absorption, flame retardancy, and CTE were evaluated.

  Furthermore, 12 μm electrolytic copper foil (3EC-M3S-HTE, manufactured by Mitsui Metals) is arranged on both sides of the obtained laminate, and a protective film (Apical 125 NPI; manufactured by Kaneka) is further used on both sides of the copper foil. Thermal lamination was performed under the conditions of 360 ° C., laminating pressure of 265 N / cm (27 kgf / cm), laminating speed of 1.0 m / min, and the peel strength, hygroscopic solder heat resistance and dimensional change rate of the obtained flexible metal-clad laminate were determined. evaluated. The results are shown in Table 1.

(Comparative Example 7)
Using the polyamic acid solution obtained in Synthesis Example 2 and a polyimide film having a thickness of 17.0 μm obtained in the same manner as the production of the polyimide film used in Comparative Example 6, the relative dielectric constant, dielectric loss tangent, water absorption The rate, flame retardancy, and CTE were evaluated.

  Furthermore, 12 μm electrolytic copper foil (3EC-M3S-HTE, manufactured by Mitsui Metals) is arranged on both sides of the obtained laminate, and a protective film (Apical 125 NPI; manufactured by Kaneka) is further used on both sides of the copper foil. When heat lamination was performed under the conditions of 360 ° C., laminating pressure of 265 N / cm (27 kgf / cm), and laminating speed of 1.0 m / min, the laminate did not adhere to the copper foil, and a suitable flexible metal-clad laminate was obtained. I couldn't.

(Comparative Example 8)
Using the polyamic acid solution obtained in Synthesis Example 2 and a polyimide film having a thickness of 34.0 μm obtained by the same method as the production of the polyimide film used in Comparative Example 6, the relative dielectric constant, dielectric loss tangent, water absorption The rate, flame retardancy, and CTE were evaluated.

  Furthermore, 12 μm electrolytic copper foil (3EC-M3S-HTE, manufactured by Mitsui Metals) is arranged on both sides of the obtained laminate, and a protective film (Apical 125 NPI; manufactured by Kaneka) is further used on both sides of the copper foil. When heat lamination was performed under the conditions of 360 ° C., laminating pressure of 265 N / cm (27 kgf / cm), and laminating speed of 1.0 m / min, the laminate did not adhere to the copper foil, and a suitable flexible metal-clad laminate was obtained. I couldn't.

(Comparative Example 9)
The relative permittivity, dielectric loss tangent, water absorption rate, flame retardance, and CTE were evaluated using a 38 μm SF resin (product name: AS-8000) film manufactured by Hitachi Chemical Co., Ltd.

  Furthermore, 12 μm electrolytic copper foil (3EC-M3S-HTE, manufactured by Mitsui Metals) is arranged on both sides of the obtained laminate, and a protective film (Apical 125 NPI; manufactured by Kaneka) is further used on both sides of the copper foil. When heat lamination was performed under the conditions of 360 ° C., laminating pressure 265 N / cm (27 kgf / cm), and laminating speed 1.0 m / min, the resin layer in the laminate flowed, and a suitable flexible metal-clad laminate was obtained. Couldn't get.

(Comparative Example 10)
The dielectric constant, dielectric loss tangent, water absorption rate, flame retardance, and CTE were evaluated using a 33 μm SF film (product name: AS-400HS) manufactured by Hitachi Chemical Co., Ltd.

  Furthermore, 12 μm electrolytic copper foil (3EC-M3S-HTE, manufactured by Mitsui Metals) is arranged on both sides of the obtained laminate, and a protective film (Apical 125 NPI; manufactured by Kaneka) is further used on both sides of the copper foil. When heat lamination was performed under the conditions of 360 ° C., laminating pressure 265 N / cm (27 kgf / cm), and laminating speed 1.0 m / min, the resin layer in the laminate flowed, and a suitable flexible metal-clad laminate was obtained. Couldn't get.

  From Table 1, in the examples having the thermosetting resin layer of the present invention at the center and the polyimide layers on both sides of the thermosetting resin layer, the relative dielectric constant as compared with Comparative Examples 5 to 8 having only the polyimide layer. As a result, the dielectric loss tangent decreased and the dielectric properties improved. Moreover, in Examples 1-4, although the thermosetting resin layer with a low storage elastic modulus is used, the dimensional stability factor becomes comparable with Comparative Examples 5 and 6 which have only a polyimide layer, and a linear expansion coefficient is also the same. It became about. That is, an increase in the dimensional stability factor and an increase in the linear expansion coefficient could be suppressed.

  In Comparative Examples 1 to 4 having a polyimide layer at the center and thermosetting resin layers on both sides of the polyimide layer, and Comparative Examples 9 and 10 having only a thermosetting resin layer, the flame retardancy was low. That is, it turned out that the use as FCCL is difficult.

Claims (9)

  A laminate having a thermosetting resin layer and a polyimide layer, wherein the thermosetting resin layer has a relative dielectric constant of 10 or less at 10 GHz, a dielectric loss tangent of 0.003 or less, A laminate having a storage elastic modulus at 20 ° C. of not less than 0.1 GPa and not more than 5.0 GPa obtained by measurement of dynamic viscoelasticity, and the polyimide layer covers both surfaces of the thermosetting resin layer . The thickness of the laminate is 25 μm or more, the thickness of the polyimide layer on one side is 0.5 μm or more, and the ratio of the thickness of the polyimide layer to the total thickness of the laminate is 4% or more and 30% or less. The laminate according to claim 1.   The laminate according to claim 1 or 2, wherein the polyimide layer is a multilayer polyimide layer having a non-thermoplastic polyimide layer and a thermoplastic polyimide layer.   The laminate according to claim 3, wherein the multilayer polyimide layer is provided so that a non-thermoplastic polyimide layer is adjacent to the thermosetting resin layer.   The laminate according to claim 4, wherein the outermost layer of the multilayer polyimide layer is a thermoplastic polyimide layer.   The relative dielectric constant at 10 GHz of the laminate is 3.0 or less, the dielectric loss tangent is 0.004 or less, and the linear expansion coefficient at 50 ° C to 250 ° C is 22 ppm or less. The laminate according to any one of the above.   The flexible metal-clad laminated board which provided the metal layer further on the at least one surface of the laminated body as described in any one of Claims 1-6.   A flexible printed circuit board comprising the metal-clad laminate according to claim 7.   A laminate for use in a flexible printed circuit board, wherein the laminate has a thermosetting resin layer and a polyimide layer, and the thermosetting resin layer has a relative dielectric constant of 3.0 or less at 10 GHz. The dielectric loss tangent is 0.003 or less, and the storage elastic modulus at 20 ° C. obtained by measurement of dynamic viscoelasticity is 0.1 GPa or more and 5.0 GPa or less, and the polyimide layer is a thermosetting resin layer. A laminate characterized by covering both sides.