WO2023157369A1 - Laminate and metal-clad laminate board having said laminate - Google Patents

Abstract

Provided is a metal-clad laminate board (for example, a copper-clad laminate board (CCL)) that, while having good electric characteristics (dielectric characteristics) adapted to 5G, has an excellent bonding property (adhesive property) between a base material film (laminate) and a metal film and has excellent dimensional stability, and of which curling is suppressed.　Also, provided is a laminate for a printed wiring board that is used to form the above metal-clad laminate board.　The laminate comprises: a low CTE resin film that has a linear coefficient of thermal expansion (CTE) of 50 ppm/℃ or less and does not have a melting point at or below 300℃; and resin films (SPS resin films) made of a styrene-based polymer having a syndiotactic structure (SPS) that are laminated on both surfaces of the low CTE resin film.

Description

Laminate and metal-clad laminate having the laminate

The present invention relates to a laminate and a metal-clad laminate having the laminate.

In recent years, with the increase in communication speed and capacity in communication devices such as smartphones, the circuit boards used in these communication devices are required to have lower electrical signal loss, finer pitch circuit patterns, and higher precision. Therefore, fine circuit formation is demanded.
Metal-clad laminates (e.g., copper-clad laminates (CCL)) in which a metal film is placed and laminated on the surface of a base film made of a so-called insulating resin, which is the main material of a circuit board, also have the above-mentioned properties. Performance similar to that of circuit boards is required.
Various improved metal-clad laminates and laminates used for the metal-clad laminates have been proposed (see, for example, Patent Document 1).

Japanese Unexamined Patent Application Publication No. 2021-75030

By the way, for the full-scale introduction of next-generation mobile communication systems such as 5G, it is desired to provide a metal-clad laminate using a base film of a low dielectric material.
However, many base films of low dielectric materials have a high CTE, and when a metal clad laminate is formed using a base film of low dielectric materials, the film shrinkage is large and the dimensional stability of the metal clad laminate is poor. In some cases, it was found that the metal-clad laminate deformed and curled. On the other hand, it has been found that even if there is no problem of dimensional stability or curling due to film shrinkage, the adhesiveness (adhesion) between the substrate film and the metal film may be poor.
For example, the copper-clad laminate (CCL) described in Patent Document 1 also has good electrical properties (dielectric properties) compatible with 5G, and the adhesiveness (adhesion) between the base film and the metal film. From the viewpoint of providing a copper-clad laminate (CCL) excellent in dimensional stability and suppressing curling, it was not sufficient.
In addition, many base films with low CTE, which are used to improve film shrinkage and dimensional stability, have poor dielectric properties. A problem arises that a metal-clad laminate having excellent properties cannot be obtained.

The present invention has been made in view of the above circumstances, and has good electrical properties (dielectric properties) compatible with 5G, and the adhesiveness (adhesion) between the base film (laminate) and the metal film. ), excellent in dimensional stability, and suppressing curling (for example, a copper clad laminate (CCL)).
Another object of the present invention is to provide a laminate for a printed wiring board, which is used to form the metal-clad laminate.

As a result of extensive research to solve the above problems, the present inventors have found that a syndiotactic structure is formed on both sides of a low CTE resin film that has a low coefficient of linear thermal expansion (CTE) and does not have a melting point below 300 ° C. The inventors have found that a laminate having a resin film (SPS resin film) made of a styrene-based polymer (SPS) having a styrenic polymer (SPS resin film) can solve the above problems, and have completed the present invention.

The present invention includes the following aspects.
[1] A low CTE resin film having a coefficient of linear thermal expansion (CTE) of 50 ppm/° C. or less and having no melting point of 300° C. or less;
A laminate obtained by laminating a resin film (SPS resin film) made of a styrene polymer (SPS) having a syndiotactic structure on both sides of the low CTE resin film.
[2] The low-CTE resin film according to [1], which is a film made of a resin selected from polyimide (PI), liquid crystal polymer (LCP), and stretched polyetheretherketone (stretched PEEK). laminate.
[3] The laminate according to [1] or [2], wherein the SPS resin film has a melting point of 250°C or higher.
[4] The laminate according to any one of [1] to [3], wherein the SPS resin film has a dielectric constant of 2.6 or less.
[5] The laminate according to any one of [1] to [4], wherein the dielectric loss tangent of the SPS resin film is less than 0.0020.
[6] The laminate according to any one of [1] to [5], wherein the SPS resin film has a water absorption rate of 0.2% or less.
[7] The laminate according to any one of [1] to [6], wherein the low CTE resin film has a water absorption rate of 2.5% or less.
[8] The ratio of the thickness of the SPS resin film to the thickness of the low-CTE resin film (the SPS resin film: the low-CTE resin film) is 1:10 to 10:1, [1] to [7] The laminate according to any one of .
[9] The laminate according to any one of [1] to [8], wherein the SPS resin film has a relative crystallinity of 25% to 85%.
[10] The surface of the low CTE resin film and/or the SPS resin film is subjected to any surface treatment selected from corona treatment, plasma treatment, and ultraviolet treatment, [1] to [9] The laminate according to any one of .
[11] The laminate according to any one of [1] to [9], wherein the surface of the low CTE resin film and/or the SPS resin film is surface-treated with a coupling agent.
[12] A metal-clad laminate obtained by laminating a metal film on one or both sides of the laminate according to any one of [1] to [11].
[13] The method for producing a laminate according to any one of [1] to [11], wherein the SPS resin film, the low CTE resin film, and the SPS resin film are arranged in this order, A method for producing a laminate, comprising thermocompression bonding to obtain the laminate.
[14] The method for producing a laminate according to [13], wherein the thermocompression bonding is performed in a temperature range of -10°C to 30°C with respect to the melting point of the SPS resin film.
[15] The method for producing a metal-clad laminate according to [12], wherein a metal film is arranged on both or one side of the laminate produced by [13] or [14], and thermocompression bonding is performed to obtain the A method for producing a metal-clad laminate to obtain a metal-clad laminate.
[16] A method for manufacturing a metal-clad laminate according to [12],
The metal film, the SPS resin film, the low CTE resin film, and the SPS resin film are arranged in this order and thermally compressed, or
The metal-clad laminate is obtained by arranging the metal film, the SPS resin film, the low-CTE resin film, the SPS resin film, and the metal film in this order and thermally compressing them to obtain the metal-clad laminate. The method of manufacturing the board.
[17] The method for producing a metal-clad laminate according to [15] or [16], wherein the thermocompression bonding is performed at a temperature range of -10°C to 30°C relative to the melting point of the SPS resin film.

According to the present invention, while having good electrical properties (dielectric properties) compatible with 5G, excellent adhesion (adhesion) between the base film (laminate) and the metal film, excellent dimensional stability, A metal-clad laminate (for example, a copper-clad laminate (CCL)) that suppresses curling can be provided.
Moreover, according to this invention, the laminated body for printed wiring boards used in order to form the said metal-clad laminated board can be provided.

It is a sectional view showing an example of composition of a layered product of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows an example of a structure of the metal-clad laminated board of this invention.

Hereinafter, the laminate for a printed wiring board of the present invention and the metal-clad laminate of the present invention formed using the laminate will be described in detail. It is an example as one embodiment, and is not specified by these contents.
The following term definitions apply throughout the specification and claims.
The melting point in the present invention can be measured according to JIS K7121. Specifically, about 5 mg of a measurement sample was weighed from a melt-extruded resin film, and a differential scanning calorimeter (manufactured by SII Technologies, Inc.: high-sensitivity differential scanning calorimeter X-DSC 7000) was used. The temperature is increased at a rate of 10°C/min, and the measurement temperature range is from 20°C to 380°C.
The film thickness of a resin film, a metal film (metal foil film), etc. is a value obtained by observing the cross section of a measurement target using a microscope, measuring the thickness at five locations, and averaging the thickness.

(Laminate)
The laminate is a laminate for a printed wiring board, and can be used for producing a metal-clad laminate (copper-clad laminate (CCL)).
The laminate is formed by laminating three layers of resin films.
The laminate comprises a low CTE resin film having a coefficient of linear thermal expansion (CTE) (CTE at 20° C. to 140° C.) of 50 ppm/° C. or less, and a styrene-based film having a syndiotactic structure on both sides of the low CTE resin film. and a resin film made of a polymer (SPS) (hereinafter also referred to as "SPS resin film").
Low CTE resin films do not have a melting point below 300°C.
In this specification, the coefficient of linear thermal expansion (CTE) is also referred to as coefficient of thermal expansion, coefficient of linear thermal expansion, or coefficient of thermal expansion.

<Layer structure of laminate>
FIG. 1 is a cross-sectional view showing an example of the structure of the laminate of the present invention.
The laminate 11 has an SPS resin film 13, a low CTE resin film 12, and an SPS resin film 14, which are laminated in this order.

<Low CTE resin film>
The low-CTE resin film is arranged in the middle of a laminate obtained by laminating three layers of resin films. The low CTE resin film has a coefficient of linear thermal expansion (CTE) (CTE from 20° C. to 140° C.) of 50 ppm/° C. or less.
Also, the low CTE resin film does not have a melting point below 300°C.
By arranging such a low-CTE resin film in the middle of the laminate, it is possible to effectively prevent deterioration of the dimensional stability of the laminate and curling of the laminate.

The coefficient of linear thermal expansion (CTE) (CTE of 20 ° C. to 140 ° C.) of the low CTE resin film is a metal film (e.g., copper film) laminated as a metal clad laminate (e.g., copper clad laminate (CCL)). ) is more excellent in suppressing curling and in dimensional stability.

The coefficient of linear expansion (CTE) can be measured using a thermomechanical analysis (TMA) device in accordance with JIS K 7197:1991. For example, in a tensile mode using a thermomechanical analyzer (product name: SII//SS7100 manufactured by Hitachi High-Tech Science Co., Ltd.), measurement is performed in the range of 10°C to 200°C under the conditions of a load of 50 mN and a heating rate of 5°C/min. Then, the coefficient of linear expansion (ppm/°C) is obtained from the slope in the range from 20°C to 140°C.

Since the low-CTE resin film does not have a melting point below 300° C., it is preferably a thermosetting resin or a film made of a thermoplastic resin having a melting point higher than 300° C. Examples include polyimide (PI) and liquid crystal. It is preferably a film made of a resin selected from polymer (LCP) and stretched polyetheretherketone (stretched PEEK).
When the low-CTE resin film is made of a thermoplastic resin and exhibits a melting point higher than 300°C, in the present invention, the low-CTE resin film must not melt at a temperature obtained by adding 30°C to the melting point of the SPS resin film. It is more preferable to have That is, in the present invention, the melting point of the low-CTE resin film is preferably higher than the sum of the melting point of the SPS resin film and 30°C.
In addition, in the present invention, a resin with high flame retardancy is selected as the resin that forms the low CTE resin film, and the low CTE resin film is a resin film with high flame resistance, thereby improving the flame retardancy. you can get a body

The low-CTE resin film can contain fillers and various additives in order to impart various functions such as adjusting the strength, insulation, heat resistance, and coefficient of linear thermal expansion (CTE) of the resin film. Examples of additives include antioxidants, light stabilizers, ultraviolet absorbers, crystal nucleating agents (nucleating agents), plasticizers, filler dispersants, and the like.

<<Filler>>
Examples of fillers include inorganic fillers and organic fillers, which can be used alone or in combination.

Examples of inorganic fillers include mica, talc, boron nitride, magnesium oxide, silica, diatomaceous earth, titanium oxide, and zinc oxide. Among them, inorganic fillers such as mica, talc, boron nitride, magnesium oxide and silica are preferred.
Examples of organic fillers include, but are not limited to, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polystyrene, polyamide, polycarbonate, polyimide, polyetherketone, polyetheretherketone, polymethylmethacrylate, liquid crystal polymer, and polytetrafluoroethylene. and other organic particles.
One of the inorganic fillers and organic fillers may be selected from the above and used alone, or two or more thereof may be used in combination. When two or more types are combined, a combination of an inorganic filler and an organic filler may be used.

<<Characteristics of low CTE resin film>>
The film thickness of the low-CTE resin film is not particularly limited, and can be appropriately selected according to the purpose. is more preferable. If it is too thick, the dielectric properties may deteriorate, and if it is too thin, curling may be suppressed and dimensional stability may become unstable.

The surface roughness (Rz) of the low-CTE resin film is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 to 10 μm, for example. If the surface roughness is too small, the film cannot be wound well, and if it is too large, problems such as unstable adhesive strength and inclusion of air bubbles when laminating the film to the SPS resin film are likely to occur.
As used herein, the surface roughness (Rz) refers to the ten-point average roughness of the film surface. The ten-point average roughness RzJIS can be obtained based on JIS B 0601:2013 (ISO 4287:1997 Amd.1:2009). In this specification, the surface roughness of each layer determined by the ten-point average roughness Rz JIS is expressed as "surface roughness (Rz)".

[Measurement of ten-point average roughness RzJIS]
The ten-point average roughness RzJIS (μm) of the surface of the sheet is obtained by measuring the roughness curve of the test piece using a laser microscope, and from this roughness curve, JIS B 0601: 2013 (ISO 4287: 1997 Amd.1: 2009), 10 samples are measured and the average value is obtained.

The dielectric constant and dielectric loss tangent of the low-CTE resin film are not particularly limited, and can be appropriately selected according to the purpose. and the dielectric loss tangent is preferably 0.025 or less.
The dielectric constant of the low-CTE resin film is preferably lower, but as a practically possible range, for example, it is preferably 2.5 to 3.5, preferably 3.0 to 3.5. more preferred. Further, the dielectric loss tangent of the low-CTE resin film is, for example, preferably 0.001 to 0.025, more preferably 0.001 to 0.01, and 0.001 to 0.008. is more preferred.

[Relative permittivity and dielectric loss tangent]
The dielectric constant and dielectric loss tangent of the resin film were measured by the open resonator method using a network analyzer MS46122B (manufactured by Anritsu) and an open resonator Fabry-Perot DPS-03 (manufactured by KEYCOM) at a temperature of 23°C. Measurement can be performed under the conditions of 50% humidity and 28 GHz frequency.

Since the base material absorbs moisture, the dielectric properties are significantly deteriorated, so the water absorption rate of the low-CTE resin film is preferably, for example, 0 to 2.5%, and is 0.01 to 2.0%. more preferably 0.03 to 1.5%, particularly preferably 0.05 to 1.2%.

[Water absorption rate]
The water absorption can be obtained by measuring under the conditions of immersion in water at 23° C. for 24 hours in accordance with the JIS K7209A method.
Calculate the water absorption from the change in mass before and after immersion in water.
Water absorption = ((mass after 24-hour water content test-mass before test)/mass before test) x 100

The surface of the low-CTE resin film is preferably subjected to any surface treatment selected from corona treatment, plasma treatment, and ultraviolet treatment for reasons such as improved adhesion.
Further, the surface of the low-CTE resin film may be surface-treated with a coupling agent for reasons such as improved adhesion.
As the silane coupling agent, a known silane coupling agent such as alkoxysilane can be used.

<SPS resin film>
SPS resin films are placed on both sides of the low CTE resin film.
By providing such an SPS resin film, it is possible to effectively prevent deterioration of the dimensional stability of the laminate and curling of the laminate together with the low CTE resin film.
The SPS resin film refers to a resin film made of a styrene-based polymer (SPS) having a syndiotactic structure, as described above.
The SPS resin film is formed using a styrenic polymer having a syndiotactic structure or a resin composition containing the styrenic polymer.

<<Styrene-based polymer (SPS) having a syndiotactic structure>>
The syndiotactic structure in the styrenic polymer having a syndiotactic structure means that the stereochemical structure is a syndiotactic structure, that is, the phenyl groups that are side chains alternate with respect to the main chain formed from carbon-carbon bonds. They have tertiary structures located in opposite directions, and their tacticity is quantified by nuclear magnetic resonance spectroscopy (13C-NMR) using carbon isotopes. The tacticity measured by the 13C-NMR method can be indicated by the abundance ratio of a plurality of consecutive constitutional units, for example, a dyad for 2 units, a triad for 3 units, and a pentad for 5 units. The styrenic polymer having a syndiotactic structure referred to in the present invention is usually 75% or more, preferably 85% or more, as racemic diad, or 30% or more, preferably 50% or more, as racemic pentad. Polystyrene, poly(alkylstyrene), poly(arylstyrene), poly(halogenated styrene), poly(halogenated alkylstyrene), poly(alkoxystyrene), poly(vinyl benzoic acid ester) having otakuticity, these It refers to hydrogenated polymers, mixtures thereof, or copolymers containing these as main components. Here, poly(alkylstyrene) includes poly(methylstyrene), poly(ethylstyrene), poly(isopropylstyrene), poly(tert-butylstyrene), etc., and poly(arylstyrene) includes: Examples include poly(phenylstyrene), poly(vinylnaphthalene), and poly(vinylstyrene). Examples of poly(halogenated styrene) include poly(chlorostyrene), poly(bromostyrene), and poly(fluorostyrene). . Examples of poly(halogenated alkylstyrene) include poly(chloromethylstyrene), and examples of poly(alkoxystyrene) include poly(methoxystyrene) and poly(ethoxystyrene).

Among these, preferred styrene polymers include polystyrene, poly(p-methylstyrene), poly(m-methylstyrene), poly(p-tertiary butylstyrene), poly(p-chlorostyrene), poly (m-chlorostyrene), poly(p-fluorostyrene), hydrogenated polystyrene and copolymers containing these structural units.

A styrenic polymer having such a syndiotactic structure can be prepared, for example, in an inert hydrocarbon solvent or in the absence of a solvent, using a titanium compound, a condensation product of water and a trialkylaluminum as a catalyst, and a styrenic monomer. (JP-A-62-187708). Further, poly(halogenated alkylstyrene) can be obtained by the method described in JP-A-1-46912, and hydrogenated polymers thereof can be obtained by the method described in JP-A-1-178505.

Among these styrenic polymers having a syndiotactic structure, in the present invention, from the viewpoint of heat resistance and mechanical strength, tacticity is 70% or more in terms of racemic pentad and weight average molecular weight is 5 to 80. Anything is preferred.

<<Resin Composition Containing Syndiotactic Polystyrene>>
The SPS resin film according to the present invention is not only a resin film formed using the syndiotactic polystyrene (SPS), but also a resin film formed using a resin composition containing syndiotactic polystyrene. can.
In this resin composition, it is necessary to contain (a) syndiotactic polystyrene as a resin component. / Or a thermoplastic resin other than the styrenic polymer having a syndiotactic structure may be included.
Furthermore, in order to impart various functions such as strength, insulation, heat resistance, and adjustment of the coefficient of linear thermal expansion (CTE) of the resin film, fillers and various additives are contained within a range that does not hinder the purpose of the present invention. can do.
The fillers and various additives are as described in the section <Low CTE resin film> above.
In addition to the additives described above, for example, antiblocking agents, antistatic agents, process oils, mold release agents, compatibilizers, flame retardants, flame retardant aids, pigments, inorganic fillers, etc. may be blended. can. In the present invention, there is no need to provide a clear distinction between fillers and various additives. For example, some apply to both fillers and inorganic fillers, while others apply to both antiblocking agents and inorganic fillers. However, in the present invention, if it can be used as one of the fillers and various additives described above, it can be contained in the resin composition.

Further, the kneading of the above components can be carried out by various methods such as blending and melt-kneading in any stage of the syndiotactic polystyrene manufacturing process, or blending and melt-kneading the components constituting the composition. Just do it.
Each component contained in the resin composition containing syndiotactic polystyrene is described below.

<<<rubber-like elastic body>>>
Specific examples of rubber-like elastomers include natural rubber, polybutadiene, polyisoprene, polyisobutylene, neoprene, polysulfide rubber, thiocol rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, and styrene-butadiene block copolymer. coalescence (SBR), hydrogenated styrene-butadiene block copolymer (SEB), styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene-isoprene block copolymer (SIR), hydrogenated styrene-isoprene block copolymer (SEP), styrene-isoprene-styrene block copolymer (SIS), hydrogenated styrene-isoprene-styrene block copolymer (SEPS), or ethylene Olefin rubber such as propylene rubber (EPM), ethylene propylene diene rubber (EPDM), linear low density polyethylene elastomer, or butadiene-acrylonitrile-styrene-core-shell rubber (ABS), methyl methacrylate-butadiene-styrene-core-shell rubber (MBS), methyl methacrylate-butyl acrylate-styrene-core-shell rubber (MAS), octyl acrylate-butadiene-styrene-core-shell rubber (MABS), alkyl acrylate-butadiene-acrylonitrile-styrene-core-shell rubber (AABS), butadiene-styrene- Examples include core-shell type elastic particles such as core-shell rubber (SBR), siloxane-containing core-shell rubber such as methyl methacrylate-butyl acrylate-siloxane, and rubber modified from these.

Among these rubber-like elastic bodies, hydrogenated styrene-butadiene-styrene block copolymer (SEBS) is preferable in the present invention from the viewpoint of heat resistance and dielectric properties.

<<<thermoplastic resin other than syndiotactic polystyrene>>>
Thermoplastic resins other than syndiotactic polystyrene include linear high-density polyethylene, linear low-density polyethylene, high-pressure low-density polyethylene, isotactic polypropylene, syndiotactic polypropylene, block polypropylene, random polypropylene, polybutene, Polyolefin resins represented by 1,2-polybutadiene, 4-methylpentene, cyclic polyolefins and copolymers thereof, atactic polystyrene, isotactic polystyrene, HIPS, ABS, AS, styrene-methacrylic acid copolymers, Styrene-methacrylic acid/alkyl ester copolymer, styrene-methacrylic acid/glycidyl ester copolymer, styrene-acrylic acid copolymer, styrene-acrylic acid/alkyl ester copolymer, styrene-maleic acid copolymer, styrene - polystyrene resins represented by fumaric acid copolymer, polyester resins such as polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyamide 6, polyamide resins such as polyamide 6,6, polyphenylene ether , polyarylene sulfide, poly-4-fluoroethylene (PTFE), and other known fluorinated polyethylene resins. Among them, polyolefins such as polyethylene and polypropylene, and polyphenylene ethers are preferred.
In addition, these thermoplastic resins can be used individually by 1 type, or in combination of 2 or more types.

<<<Additives>>>
Various additives exemplified below can be blended as long as they do not hinder the object of the present invention.

[Anti-blocking agent (AB agent)]
Antiblocking agents include inorganic or organic particles such as:
Examples of inorganic particles include oxides, hydroxides, sulfides, nitrides and halogens of group IA, IIA, IVA, VIA, VIIA, VIII, IB, IIB, IIIB, and IVB elements. compounds, carbonates, sulfates, acetates, phosphates, phosphites, organic carboxylates, silicates, titanates, borates, their hydrous compounds, composite compounds centering on them, and natural mineral particles mentioned.

Specifically, lithium fluoride, group IA element compounds such as borax (sodium borate hydrate), magnesium carbonate, magnesium phosphate, magnesium oxide (magnesia), magnesium chloride, magnesium acetate, magnesium fluoride, magnesium titanate, Magnesium silicate, magnesium silicate hydrate (talc), calcium carbonate, calcium phosphate, calcium phosphite, calcium sulfate (gypsum), calcium acetate, calcium terephthalate, calcium hydroxide, calcium silicate, calcium fluoride, calcium titanate, titanium Group IIA element compounds such as strontium oxide, barium carbonate, barium phosphate, barium sulfate, and barium sulfite; group IVA element compounds such as titanium dioxide (titania), titanium monoxide, titanium nitride, zirconium dioxide (zirconia), and zirconium monoxide; VIA group element compounds such as molybdenum dioxide, molybdenum trioxide and molybdenum sulfide; VIIA group element compounds such as manganese chloride and manganese acetate; VIII group element compounds such as cobalt chloride and cobalt acetate; and IB group elements such as cuprous iodide. Compounds, group IIB element compounds such as zinc oxide and zinc acetate, group IIIB element compounds such as aluminum oxide (alumina), aluminum hydroxide, aluminum fluoride, alumina silicate (alumina silicate, kaolin, kaolinite), silicon oxide (silica , silica gel), IVB group element compounds such as graphite, carbon, graphite, and glass, and particles of natural minerals such as carnalite, kainite, mica (mica, cinnamon), and biroseite.

Organic particles include Teflon, melamine-based resins, styrene-divinylbenzene copolymers, acrylic resins, and crosslinked products thereof.

[Antioxidant]
The antioxidant can be arbitrarily selected from known antioxidants such as phosphorus-based, phenol-based, and sulfur-based antioxidants. In addition, these antioxidants can be used individually by 1 type, or in combination of 2 or more types.

[Nucleating agent]
Nucleating agents include carboxylic acid metal salts such as aluminum di(pt-butylbenzoate), phosphoric acid metal salts such as methylenebis(2,4-di-t-butylphenol) acid phosphate sodium, and talc. , phthalocyanine derivatives, etc., can be arbitrarily selected and used. These nucleating agents can be used singly or in combination of two or more.

[Plasticizer]
The plasticizer can be arbitrarily selected from known ones such as polyethylene glycol, polyamide oligomer, ethylene bis-stearamide, phthalate ester, polystyrene oligomer, polyethylene wax, and silicone oil. In addition, these plasticizers can be used individually by 1 type, or in combination of 2 or more types.

[Release agent]
As the release agent, it is possible to arbitrarily select and use known ones such as polyethylene wax, silicone oil, long-chain carboxylic acid, and long-chain carboxylic acid metal salt. These release agents can be used singly or in combination of two or more.

[Process oil]
In the present invention, process oil may be further blended. Process oils are broadly classified into paraffinic oils, naphthenic oils, and aromatic oils, depending on the type of oil, with paraffinic oils being preferred. As for the viscosity of the process oil, the kinematic viscosity at 40° C. is preferably 15 to 600 cs, more preferably 15 to 500 cs.
These process oils can be used singly or in combination of two or more.

[Compatibilizer]
The compatibilizer as used in the present invention improves the affinity between syndiotactic polystyrene and thermoplastic resin and/or rubber-like elastomer to effectively compatibilize the syndiotactic polystyrene and inorganic filler. Blended to improve affinity with. Specific examples include polymers having compatibility or affinity with syndiotactic polystyrene and having polar groups.

Here, a polymer having compatibility or affinity with syndiotactic polystyrene means a polymer containing a chain exhibiting compatibility or affinity with syndiotactic polystyrene in the polymer chain. Polymers exhibiting compatibility or affinity for these include, for example, syndiotactic polystyrene, atactic polystyrene, isotactic polystyrene, styrenic copolymers, polyphenylene ether, polyvinyl methyl ether, etc. as main chains, blocks or grafts. Those having as a chain, etc. are mentioned.

In addition, the polar group as used herein may be any group that improves adhesion to the inorganic filler, and specifically includes an acid anhydride group, a carboxylic acid group, a carboxylic acid ester group, and a carboxylic acid chloride group. , carboxylic acid amide group, carboxylic acid group, sulfonic acid group, sulfonic acid ester group, sulfonic acid chloride group, sulfonic acid amide group, sulfonic acid group, epoxy group, amino group, imide group, oxazoline group and the like.

This compatibilizing agent can be obtained by reacting the above polymer having compatibility or affinity with syndiotactic polystyrene with a modifying agent described later in the presence or absence of a solvent or other resin.
As modifiers, for example, compounds containing an ethylenic double bond and a polar group in the same molecule can be used. Specifically, maleic anhydride, maleic acid, maleic acid ester, maleimide and its N-substituted products, maleic acid derivatives such as maleate, fumaric acid such as fumaric acid, fumaric acid ester, and fumarate derivatives, itaconic anhydride, itaconic acid, itaconic acid esters, itaconic acid derivatives including itaconic acid salts, acrylic acid, acrylic acid esters, acrylic acid amides, acrylic acid derivatives including acrylic acid salts, methacrylic acid, methacrylic acid Acid esters, methacrylic acid amides, methacrylic acid salts, methacrylic acid derivatives such as glycidyl methacrylate, and the like. Among them, maleic anhydride, fumaric acid and glycidyl methacrylate are particularly preferred.

Known methods are used for modification, but a method of melt-kneading and reacting at a temperature of 150° C. to 350° C. using a roll mill, a Banbury mixer, an extruder, etc., and a method of reacting with a solvent such as benzene, toluene, xylene, etc. A method of heat-reacting in the inside can be exemplified. Furthermore, in order to facilitate these reactions, benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, t-butyl peroxybenzoate, azobisisobutyronitrile, and azobisiso are added to the reaction system. The presence of a radical generator such as valeronitrile, 2,3-diphenyl-2,3-dimethylbutane is effective. Of these, 2,3-diphenyl-2,3-dimethylbutane is particularly preferred.

A preferred modification method is a method of melt-kneading in the presence of a radical generator. Also, other resins may be added during modification. Specific examples of compatibilizers include styrene-maleic anhydride copolymer (SMA), styrene-glycidyl methacrylate copolymer, terminal carboxylic acid-modified polystyrene, terminal epoxy-modified polystyrene, terminal oxazoline-modified polystyrene, terminal amine-modified polystyrene, Sulfonated polystyrene, styrene ionomer, styrene-methyl methacrylate-graft polymer, (styrene-glycidyl methacrylate)-methyl methacrylate-graft copolymer, acid-modified acrylic-styrene-graft polymer, (styrene-glycidyl methacrylate)-styrene-graft Polymers, polybutylene terephthalate-polystyrene-graft polymers, maleic anhydride-modified PS, fumaric acid-modified PS, glycidyl methacrylate-modified PS, amine-modified PS and other modified styrenic polymers, (styrene-maleic anhydride)-polyphenylene ether-graft polymers , maleic anhydride-modified polyphenylene ether, glycidyl methacrylate-modified polyphenylene ether, amine-modified polyphenylene ether, and other modified polyphenylene ether polymers.

Of these, modified PS and modified polyphenylene ether are particularly preferred. Two or more of the above polymers can be used in combination. The polar group content in the compatibilizer is preferably in the range of 0.01 to 20% by mass, more preferably 0.05 to 10% by mass based on 100% by mass of the compatibilizer. If it is less than 0.01% by mass, it is necessary to add a large amount of a compatibilizing agent in order to exhibit an adhesive effect with the inorganic filler, and this is preferable because there is a possibility that the mechanical properties, heat resistance, and moldability of the composition may be deteriorated. do not have. On the other hand, if it exceeds 20% by mass, the compatibility with syndiotactic polystyrene may decrease, which is not preferable.

The content of the compatibilizer is 0.1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, based on 100 parts by mass of the syndiotactic polystyrene resin, the thermoplastic resin and/or the rubber-like elastic body. More preferably, it is 1 to 5 parts by mass. If it is less than 0.1 part by mass, the effect of adhesion to the inorganic filler is small, resulting in insufficient adhesion between the resin and the inorganic filler. become.

[Inorganic filler]
As inorganic fillers, granular and powdery fillers are preferred, and examples include talc, carbon black, graphite, titanium dioxide, silica, mica, calcium carbonate, calcium sulfate, barium carbonate, magnesium carbonate, magnesium sulfate, barium sulfate, oxy Sulfate, tin oxide, alumina, kaolin, silicon carbide, metal powder, glass powder, glass flakes, glass beads and the like.

In addition, surface-treated ones may be used as these fillers. The coupling agent used for the surface treatment is used to improve the adhesion between the filler and the resin. Any one can be selected and used. In addition, about these inorganic fillers, only 1 type can be used individually or in combination of 2 or more types.

<<Characteristics of SPS resin film>>
The film thickness of each SPS resin film arranged on both sides of the low-CTE resin film is not particularly limited, and can be appropriately selected according to the purpose. more preferably 20 μm to 55 μm.

The ratio of the thickness of each SPS resin film (single-layer SPS resin film) arranged on both sides of the low-CTE resin film to the thickness of the low-CTE resin film (SPS resin film: low-CTE resin film) is 1:10. ~10:1 is preferred, 1:5 to 5:1 is more preferred, and 1:3 to 3:1 is even more preferred. If the SPS resin film is too thin, transmission characteristics may deteriorate, and if the SPS resin film is too thick, curling may occur and dimensional stability may deteriorate.
Moreover, the thickness of the SPS resin film is more preferably the same as or thinner than the thickness of the low-CTE resin film. Therefore, the ratio of SPS resin film:low CTE resin film is particularly preferably 1:2 to 1:1.

The surface roughness (Rz) of the SPS resin film at the interface between the low CTE resin film and the SPS resin film is not particularly limited and can be appropriately selected according to the purpose. preferable.
On the other hand, the surface roughness (Rz) of the SPS resin film at the interface between the SPS resin film and the metal film is not particularly limited and can be appropriately selected depending on the purpose. preferable.

The melting point of the SPS resin film is preferably 250° C. or higher.
Also, the SPS resin film preferably has a dielectric constant of 2.6 or less. Also, the dielectric loss tangent of the SPS resin film is preferably less than 0.0020, more preferably 0.0016 or less, even more preferably 0.0012 or less.
The water absorption rate of the SPS resin film is preferably 0.2% or less, more preferably 0.15% or less, and even more preferably 0.10% or less.
A metal-clad laminate (for example, a copper-clad laminate (CCL)) having an SPS resin film that satisfies these properties has good electrical properties (dielectric properties) compatible with 5G.
The relative dielectric constant of the SPS resin film is preferably as low as possible, but from the necessity of the resin having solder heat resistance, for example, it is preferably 2.0 to 2.6, and 2.1 to 2.4. It is more preferable to have In addition, the dielectric loss tangent of the SPS resin film is preferably as low as possible. 0.0016 is more preferred, 0.0005 to 0.0012 is even more preferred, and 0.0005 to 0.0007 is particularly preferred.

Since the base material absorbs moisture, the dielectric properties are significantly deteriorated, so the water absorption rate of the SPS resin film is preferably, for example, 0 to 0.2%, and preferably 0.01 to 0.15%. is more preferable, and 0.03 to 0.06% is even more preferable.

[Water absorption rate]
The water absorption can be obtained by measuring under the conditions of immersion in water at 23° C. for 24 hours in accordance with the JIS K7209A method.
Calculate the water absorption from the change in mass before and after immersion in water.
Water absorption = ((mass after 24-hour water content test-mass before test)/mass before test) x 100

Furthermore, the elongation at tensile break in the machine direction (MD direction) of the SPS resin film is preferably 400% or less.

The tensile elongation at break in the longitudinal direction (MD direction) of the SPS resin film (also called the extrusion direction of the film) is 400% or less as described above, but preferably 2 to 350%, for example. If the elongation is too large, problems such as wrinkles may occur during lamination with a low-CTE film or metal film.

[Elongation at break (%)]
The elongation at break of the SPS resin film is obtained by measuring the elongation in the longitudinal direction of the film (that is, the extrusion direction of the film) at a tensile speed of 50 mm / min and a temperature of 23 ° C. in accordance with JIS K7127. can be done.

The relative crystallinity of the SPS resin film is preferably 25-85%, more preferably 30-80%, even more preferably 35-70%.
This is because, if the relative crystallinity of the SPS resin film is within the above range, it can be expected to ensure the peel strength and heat dimensional stability that can be used as a laminate.

[Relative crystallinity (%)]
The crystallinity of the SPS resin film can be represented by relative crystallinity. The relative crystallinity of the SPS resin film can be measured, for example, by peeling off only the SPS resin film portion from the prepared metal-clad laminate, and using a differential scanning calorimeter on the SPS resin film at a heating rate of 10 ° C./min. It can be obtained by calculating from the following formula based on the thermal analysis results measured in .
Relative crystallinity (%) = {(|ΔHm|-|ΔHc|)/|ΔHm|}×100
Here, ΔHc: heat quantity (J/g) at recrystallization peak, ΔHm: heat quantity (J/g) at melting peak.

As shown in FIG. 1, the SPS resin films are arranged on both sides of the low CTE resin film 12, and the SPS resin films 13 and 14 have the same composition as long as they satisfy the above requirements. It may be a resin film of the same composition or a resin film of a different composition.

The surface of the SPS resin film is preferably subjected to any surface treatment selected from corona treatment, plasma treatment, and ultraviolet treatment for reasons such as improved adhesion.
In addition, the surface of the SPS resin film may be surface-treated with a coupling agent for reasons such as improved adhesion.

<Method for producing resin film>
A resin film can be obtained, for example, by molding a resin into a film by a melt extrusion molding method.
The melt extrusion molding method is a molding method in which a resin material is melt-kneaded using a melt extruder, and the resin material is continuously extruded from a T-die of the melt extruder.
For example, a resin material melt-kneaded by a melt extruder is continuously extruded into a belt-shaped resin film by a T-die at the tip of the melt extruder, and this continuous resin film is placed next. It is placed between rolls, cooled, and then wound on a winder. Thus, a resin film is produced.
The extruder is not particularly limited, and any molding machine such as a single-screw extruder or a twin-screw extruder can be used.

(Metal clad laminate)
The metal-clad laminate of the present invention is obtained by laminating a metal film on one or both sides of the laminate of the present invention.

An SPS resin film, a low CTE resin film, an SPS resin film, and a metal film are laminated in this order.
In the metal-clad laminate of the present invention, metal films may be laminated on both sides of the base film. The metal-clad laminate in this case is formed by laminating a metal film, an SPS resin film, a low-CTE resin film, an SPS resin film, and a metal film in this order.

FIG. 2 is a cross-sectional view showing an example of the configuration of the metal-clad laminate of the present invention. FIG. 2 shows an example in which metal films are laminated on both sides of the laminate.
The metal-clad laminate 21 has a metal film 25, an SPS resin film 23, a low CTE resin film 22, an SPS resin film 24, and a metal film 26, which are laminated in this order.

The metal constituting the metal film is not particularly limited and can be appropriately selected depending on the intended purpose. An alloy or the like containing one or more selected types may be mentioned. Among them, copper and alloys containing copper are preferable from the viewpoint of shielding properties and economy.
A preferred embodiment of the metal-clad laminate of the present invention is a metal-clad laminate in which a metal foil film is attached to a laminate. Among them, a copper-clad laminate obtained by bonding a copper foil film (copper foil film) to a laminate, in which the metal foil is copper foil, is more preferable.

<Metal film>
A preferred embodiment of the metal film is a metal foil film.
The type of metal foil is not particularly limited, and for example, an electrolytic metal foil, a rolled metal foil, or the like can be used.
Among metal foils, copper foil is more preferable.

The film thickness of the metal foil is preferably 0.05 μm to 20 μm from the viewpoint of ensuring sufficient electrical signal transmission characteristics and enabling a fine pitch of the circuit pattern, and 0.1 μm. More preferably ~15 μm.
The surface roughness (Rz) of the metal foil film at the interface between the metal foil film and the SPS resin film is preferably 0.5 μm or less from the viewpoint of transmission characteristics due to the skin effect, and is 0.3 μm or less. is more preferable.

<Film thickness of metal-clad laminate>
The film thickness of the metal-clad laminate is not particularly limited and can be appropriately selected according to the purpose, but is preferably 10 to 300 μm, for example. When the film thickness of the metal-clad laminate is at least the lower limit value of the above range, the handleability is excellent and the strength can be ensured. Moreover, when the thickness is equal to or less than the upper limit of the above range, lightness, thinness, shortness and flexibility can be imparted.

(Laminate manufacturing method)
The laminate is produced by arranging an SPS resin film, a low CTE resin film, and an SPS resin film in this order, sandwiching them with a heat press or between heating rolls or between heating belts, followed by heating and pressing. It includes a step of bonding each resin film by thermocompression bonding.
The thermocompression bonding is preferably carried out in a temperature range of −10° C. to 30° C., more preferably −10° C. to 20° C. relative to the melting point of the SPS resin film.
In addition, the pressure in the thermocompression bonding is preferably 0.2 to 10 MPa, more preferably 1 to 5 MPa, for example, in the case of a hot press or a heating belt, and the thermocompression bonding time is 1 to 30 minutes. is preferably In the case of a heating roll, it is desirable that the line pressure is 4-60 kN/m and the line speed is 0.5-5.0 m/min.

(Method for producing metal-clad laminate)
A method for producing a metal-clad laminate includes the steps of disposing metal films on both or one side of the laminate, thermally compressing the laminate, and laminating the laminate and the metal film.
In addition, in the method for producing a metal-clad laminate, a metal film, an SPS resin film, a low CTE resin film, and an SPS resin film are arranged in this order, and these are placed in a hot press or between heating rolls or between heating belts. Then, the metal film and each resin film are bonded together by heat and pressure and thermocompression bonding, or the metal film, the SPS resin film, the low CTE resin film, the SPS resin film, and the metal film are bonded together. It includes a step of arranging them in order, thermally compressing them, and bonding the metal film and each resin film.
The thermocompression bonding is preferably carried out in a temperature range of −10° C. to 30° C., more preferably −10° C. to 20° C. relative to the melting point of the SPS resin film.

When the metal-clad laminate is a metal-clad laminate having metal films on both sides of the laminate as shown in FIG. A metal-clad laminate may be produced by laminating a film and then laminating a metal film on the other side of the laminate in the same manner, or alternatively, The metal films may be laminated together to produce a metal clad laminate with the metal films on both sides at once.

Before forming the metal film, the surface of the SPS resin film in contact with the metal film may be surface-treated by corona treatment, plasma treatment, ultraviolet treatment, or the like.

The laminate (particularly, the double-sided metal-clad laminate) of the present invention has good electrical properties (dielectric properties) and excellent adhesiveness (adhesion) between the base film (laminate) and the metal film. Since it is excellent in dimensional stability and curl suppression, it can be suitably used for manufacturing flexible printed circuit boards and rigid printed circuit boards.
For example, by etching or electroplating (semi-additive method (SAP method), modified semi-additive method (MSAP method)), the metal substrate of the metal-clad laminate of the present invention is formed into a transmission circuit (conductor circuit) having a predetermined shape. If processed, printed circuit boards can be produced.
In manufacturing the printed circuit board, after forming the transmission circuit, an interlayer insulating film may be formed on the transmission circuit, and a further transmission circuit may be formed on the interlayer insulating film. Moreover, you may laminate|stack a solder resist and a cover-lay film on a transmission circuit.

Although the present invention will be described in more detail with examples below, the scope of the present invention is not limited to these examples. In the following, parts and % are based on mass unless otherwise specified.

(Water absorption (%))
The water absorption was measured under the conditions of immersion in water at 23°C for 24 hours in accordance with JIS K7209A method. The water absorption was obtained from the change in mass before and after immersion in water.

(dielectric properties)
Dielectric properties (relative permittivity, dielectric loss tangent) were measured using an electronic measuring instrument (product name: compact USB vector network analyzer MS46122B: manufactured by Anritsu) using the Fabry-Perot method, which is a kind of open resonator method, at a frequency of around 28 GHz. Dielectric properties were measured at 23° C.×50 RH %. An open-type resonator (product name: Fabry-Perot resonator Model No. DPS03: manufactured by Keycom Co., Ltd.) was used.

(Coefficient of linear thermal expansion (CTE) (ppm/°C))
The coefficient of linear thermal expansion (CTE) is 10° C. under the conditions of a load of 50 mN and a heating rate of 5° C./min in a tensile mode using a thermomechanical analyzer (product name: SII//SS7100, manufactured by Hitachi High-Tech Science Co., Ltd.). to 200°C, and the coefficient of linear thermal expansion (ppm/°C) was obtained from the slope in the range from 20°C to 140°C. The width direction (TD) of the resin film was measured.

(Melting point (°C))
The melting point was measured according to JIS K7121. Specifically, about 5 mg of a measurement sample was weighed from a melt-extruded resin film, and a differential scanning calorimeter (manufactured by SII Technologies, Inc.: high-sensitivity differential scanning calorimeter X-DSC 7000) was used. The temperature was raised at a rate of 10°C/min, and the measurement temperature range was from 20°C to 380°C.

The resin films and copper foil films used in the following examples and comparative examples are as follows. Also, the properties of the resin film are shown in Table 1 below. The SPS resin used for the SPS(2) film and the SPS(3) film is the SPS resin used for molding the SPS(1) film.

(resin film)
SPS film: SPS (1) film manufactured by Shin-Etsu Polymer Co., Ltd. SPS film: SPS (2) film manufactured by Shin-Etsu Polymer Co., Ltd. (SPS resin: synthetic mica = 95:5 mass ratio)
SPS film: SPS (3) film manufactured by Shin-Etsu Polymer Co., Ltd. (SPS resin: synthetic mica = 80:20 mass ratio)
PI film: PI Kapton (registered trademark) H series manufactured by DuPont Toray PI film: PI Kapton (registered trademark) LK series manufactured by DuPont Toray PI film: PI Kapton (registered trademark) EN series manufactured by DuPont Toray LCP film: Shin-Etsu polymer High melting point LCP (1) film manufactured by Co., Ltd. Stretched PEEK film: Stretched PEEK film manufactured by Kurabo Industries Unstretched PEEK (polyetheretherketone) film: Unstretched PEEK film manufactured by Shin-Etsu Polymer Co., Ltd. PPS (polyphenylene sulfide) film: PPS manufactured by Shin-Etsu Polymer Co., Ltd. Film TPI (thermoplastic polyimide) film: TPI film manufactured by Shin-Etsu Polymer Co., Ltd. LCP film: Low melting point LCP (2) film (copper foil film) manufactured by Shin-Etsu Polymer Co., Ltd.
Copper foil: CF-T9DA-SV-12 manufactured by Fukuda Metal Foil and Powder Co., Ltd. (Rz: 0.21 μm, CTE: 18 ppm/° C.)

 

 

(Example 1)
A polyimide film (PI) (PI Kapton (registered trademark) LK series manufactured by DuPont-Toray Co., Ltd.) shown in Table 1 having a thickness of 50 μm was prepared.
The front and back surfaces of the polyimide film were subjected to corona treatment.
On both sides of the polyimide film, 25 μm-thick SPS films shown in Table 1 (manufactured by Shin-Etsu Polymer Co., Ltd., a resin film made of a styrene-based polymer having a syndiotactic structure) were placed.
Furthermore, a copper foil film with a thickness of 12 μm (CF-T9DA manufactured by Fukuda Metal Foil & Powder Co., Ltd.) is placed on both sides of the outermost surface, sandwiched between stainless steel plates (SUS plates) with a thickness of 1 mm using a heat press, and pressure is applied. The pressure was set to 3 MPa and the hot plate temperature of the hot press machine was set to 285° C., and thermocompression bonding was performed for 5 minutes.
After thermocompression, the hot plate of the hot press was cooled to 270°C at a rate of 4°C/min (this cooling method is referred to as cooling 1), and then the pressure was released to obtain the copper of Example 1. The tension laminate (CCL) was removed.
The structure of the copper-clad laminate of Example 1 thus obtained is shown in Table 2 below.
Only the SPS resin film was peeled off from the obtained copper-clad laminate of Example 1, and the relative crystallinity of the SPS resin film was determined according to the following procedure. Such values are also shown in Table 2 below.

(Relative crystallinity)
Regarding the relative crystallinity of the SPS resin film, only the SPS resin film was peeled off from the prepared copper-clad laminate, about 8 mg of the measurement sample was weighed, and a differential scanning calorimeter (manufactured by SII Nano Technologies Co., Ltd. (product name: EXSTAR7000 Series X-DSC7000)) was used to measure the temperature from 20°C to 300°C at a heating rate of 10°C/min. The relative crystallinity of the SPS resin film was calculated from the heat quantity (J/g) at the crystal melting peak and the heat quantity (J/g) at the recrystallization peak obtained at this time using the following formula.
Relative crystallinity (%) = {(|ΔHm|-|ΔHc|)/|ΔHm|}×100
(Here, ΔHc: recrystallization peak heat quantity (J/g), ΔHm: melting peak heat quantity (J/g).)

The copper-clad laminate of Example 1 was evaluated for curl, 250°C dimension, transmission characteristics, and peel strength by the following evaluation methods. The results are shown in Table 4 below.

(Curl test)
A specimen of 150 x 150 mm in size was cut out from the obtained copper-clad laminate (CCL), only the copper foil on one side of the specimen was removed with an aqueous ferric chloride solution, and the specimen was placed on a flat glass plate. , and the amount of lifting at four points at the four corners of the specimen was measured with a ruler, and the average value was obtained.

[Evaluation Criteria for Curl Test]
○ 4-point average is 3 cm or less △ 4-point average is greater than 3 cm and 5 cm or less × 4-point average is greater than 5 cm

(250°C dimension test)
The 250° C. dimensional shrinkage rate test was measured in accordance with JIS C 6481:1996.
First, a copper clad laminate (CCL) was cut into a size of 300 x 300 mm, holes were made at four points at the ends of the laminate, and the distance between the centers of the holes was measured. It was removed with an aqueous iron solution, placed in an oven at 250° C. for 30 minutes, taken out, and then measured.
A two-dimensional length measuring machine (product name: VMH600, manufactured by Mino Group) was used for measuring the dimensions.

[Evaluation criteria for 250°C dimension test]
〇 Shrinkage rate is 0.2% or less (good shrinkage rate)
Δ Shrinkage rate greater than 0.2% and 0.4% or less × Shrinkage rate greater than 0.4% (poor shrinkage rate)

(Transmission characteristic test)
In the transmission characteristics test, a microstrip line with a length of 10 cm and an impedance of 50Ω was prepared by etching the copper foil in the copper clad laminate (CCL), and the transmission characteristics at 30 GHz were measured under the conditions of a temperature of 25°C and a humidity of 50%. It was measured. As a measuring instrument, a network analyzer E8363B (manufactured by Keysight Technologies) was used.

[Evaluation Criteria for Transmission Characteristics Test]
◎ 4 dB or less 〇 Greater than 4 dB and 5 dB or less △ Greater than 5 dB and 10 dB or less × Greater than 10 dB

(Peel strength test)
In the peel strength test, a copper-clad laminate (CCL) was cut into a test piece with a width of 25 mm. The plate (CCL) was fixed to a support, the copper foil was fixed to a tension jig, and the peel strength was measured when the copper foil was pulled from the copper clad laminate (CCL).

[Evaluation Criteria for Peel Strength Test]
○ 7 N/cm or more △ 3 N/cm or more and less than 7 N/cm × 3 N/cm or less

(Examples 2 to 18)
Copper clads of Examples 2 to 18 were prepared in the same manner as in Example 1, except that the type of resin film used, the thermocompression bonding temperature, and the cooling method conditions were changed as shown in Table 2. A laminate was produced.
In Table 2 (the same applies to Table 3 below), cooling method 2 (cooling 2) and cooling method 3 (cooling 3) are performed by cooling the copper clad laminate after thermocompression bonding by the following methods, respectively, and removing it from the heat press. It means to take out.
Cooling 2: After thermocompression, the hot plate of the hot press is cooled to 230°C at a rate of 4°C/min, the pressure is released, and the copper-clad laminate is taken out.
Cooling 3: After thermocompression bonding, the pressure is released without cooling the hot plate of the hot press, and the copper-clad laminate is taken out.

The relative crystallinity of the SPS resin film was determined in the same manner as in Example 1 for the copper clad laminates produced in Examples 2 to 18. Also, in the same manner as in Example 1, the curl, 250° C. dimension, transmission characteristics, and peel strength were evaluated.
Table 2 shows the relative crystallinity results of the SPS resin films in the copper clad laminates of Examples 2 to 18.
Table 4 shows evaluation results of curl, 250° C. dimension, transmission characteristics, and peel strength for the copper clad laminates of Examples 2 to 18.

(Comparative Examples 1 to 5)
Copper clads of Comparative Examples 1 to 5 were prepared in the same manner as in Example 1 except that the type of resin film used, the thermocompression bonding temperature, and the cooling method conditions were changed as shown in Table 3. A laminate was produced.

The relative crystallinity of the SPS resin film was determined in the same manner as in Example 1 for the copper clad laminates produced in Comparative Examples 1 to 5. Also, in the same manner as in Example 1, the curl, 250° C. dimension, transmission characteristics, and peel strength were evaluated.
Table 3 shows the results of the relative crystallinity of the SPS resin films in the copper clad laminates of Comparative Examples 1 to 5.
Table 4 shows evaluation results of curl, 250° C. dimension, transmission characteristics, and peel strength for the copper-clad laminates of Comparative Examples 1 to 5.

 

 

 

 

 

 

From the examples, the metal-clad laminate of the present invention has good electrical properties (dielectric properties), excellent adhesiveness (adhesion) between the base film (laminate) and the metal film, and dimensional stability. It was confirmed that the metal-clad laminate was excellent in curling and suppressed in curling.

The metal-clad laminate of the present invention can be suitably used for manufacturing FPC-related products for electronic devices such as smart phones, mobile phones, optical modules, digital cameras, game machines, notebook computers, and medical instruments.

REFERENCE SIGNS LIST 11 laminate 12 low CTE resin film 13 SPS resin film 14 SPS resin film 21 metal clad laminate 22 low CTE resin film 23 SPS resin film 24 SPS resin film 25 metal film 26 metal film

Claims (17)

a low CTE resin film having a coefficient of linear thermal expansion (CTE) of 50 ppm/° C. or less and having no melting point of 300° C. or less;
A laminate obtained by laminating a resin film (SPS resin film) made of a styrene polymer (SPS) having a syndiotactic structure on both sides of the low CTE resin film. The laminate according to claim 1, wherein the low-CTE resin film is a film made of a resin selected from polyimide (PI), liquid crystal polymer (LCP), and stretched polyetheretherketone (stretched PEEK). The laminate according to claim 1, wherein the SPS resin film has a melting point of 250°C or higher. The laminate according to claim 1, wherein the SPS resin film has a dielectric constant of 2.6 or less. The laminate according to claim 1, wherein the SPS resin film has a dielectric loss tangent of less than 0.0020. The laminate according to claim 1, wherein the SPS resin film has a water absorption rate of 0.2% or less. The laminate according to claim 1, wherein the low CTE resin film has a water absorption rate of 2.5% or less. The laminate according to claim 1, wherein the ratio of the thickness of said SPS resin film to the thickness of said low CTE resin film (said SPS resin film: said low CTE resin film) is 1:10 to 10:1. The laminate according to claim 1, wherein the SPS resin film has a relative crystallinity of 25% to 85%. The laminate according to claim 1, wherein the surface of the low-CTE resin film and/or the SPS resin film is subjected to any surface treatment selected from corona treatment, plasma treatment, and ultraviolet treatment. The laminate according to claim 1, wherein the surfaces of the low-CTE resin film and/or the SPS resin film are surface-treated with a coupling agent. A metal-clad laminate obtained by laminating a metal film on one or both sides of the laminate according to any one of claims 1 to 11. The method for producing a laminate according to any one of claims 1 to 11, wherein the SPS resin film, the low CTE resin film, and the SPS resin film are arranged in this order and thermocompression bonded, A method for manufacturing a laminate to obtain the laminate. The method for producing a laminate according to claim 13, wherein the thermocompression bonding is performed in a temperature range of -10°C to 30°C with respect to the melting point of the SPS resin film. A method for producing a metal-clad laminate, comprising placing metal films on both or one side of the laminate produced according to claim 13 and thermally compressing to obtain the metal-clad laminate. The metal film, the SPS resin film, the low CTE resin film, and the SPS resin film are arranged in this order and thermally compressed, or
The metal-clad laminate according to claim 12 is obtained by arranging the metal film, the SPS resin film, the low-CTE resin film, the SPS resin film, and the metal film in this order and thermally compressing them. A method for producing a metal-clad laminate obtained. 17. The method for producing a metal-clad laminate according to claim 16, wherein the thermocompression bonding is performed at a temperature range of -10°C to 30°C with respect to the melting point of the SPS resin film.