Patent Application
20240368323
The present invention relates to a resin composition, and a prepreg using the resin composition, a film with resin, a metal foil with resin, a metal-clad laminate, and a wiring board.
In recent years, in various electronic devices, mounting technologies such as higher integration of semiconductor devices to be mounted, higher wiring density, and multi-layering have rapidly progressed along with an increase in the amount of information processed. Substrate materials for forming base materials of wiring boards used in various electronic devices are required to have a low dielectric constant and a low dielectric loss tangent to increase the transmission speed of signals and decrease the loss during signal transmission.
In particular, as typified by substrate-like printed wiring boards (SLP), the barrier between printed wiring boards and semiconductor package substrates is disappearing in recent years. Therefore, with the recent miniaturization and high performance of electronic devices and the remarkable improvement of information communication speed, any substrate is required to be compatible with high frequencies as well as exhibit excellent heat resistance and low thermal expansion properties.
As a material for such substrates, maleimide resin is used since high heat resistance can be secured, and maleimide affording a low dielectric constant and a low dielectric loss tangent has been proposed in order to achieve compatibility with high frequencies and low transmission loss.
For example, Patent Literature 1 discloses a resin composition affording well-balanced cured product properties between heat resistance and dielectric properties (relative dielectric constant, dielectric loss tangent) by combining a polymaleimide resin having a specific structure and an unsaturated double bond group-containing compound.
Patent Literature 2 reports a curable resin composition capable of imparting a low dielectric constant and a low dielectric loss tangent as well as an excellent heat resistance to its cured product by containing a maleimide having an indane skeleton and a diene-based polymer.
However, it is required to secure even lower dielectric properties although a certain degree of low dielectric properties can be attained by use of the maleimide resins described in Patent Literatures 1 and 2.
In order to suppress warpage in substrates using electronic materials, and the like, it is also required to increase the rigidity of substrates, in particular, there is a demand for an electronic material affording a cured product that has little changes in modulus at high temperatures (during heating and the like) as well.
The present invention is made in view of such circumstances, and an object thereof is to provide a resin composition affording a cured product that exhibits low dielectric properties, a high glass transition temperature (Tg), and rigidity. Another object of the present invention is to provide a prepreg, a film with resin, a metal foil with resin, a metal-clad laminate, and a wiring board, which are obtained using the resin composition.
A resin composition according to an aspect of the present invention contains a maleimide compound (A) having a benzene ring in the molecule and a hydrocarbon-based compound (B) represented by the following Formula (1), and the maleimide compound (A) contains a maleimide compound (A-1) having a maleimide group equivalent of 400 g/mol or less.
[In Formula (1), X represents a hydrocarbon group having 6 or more carbon atoms and containing at least one selected from an aromatic cyclic group or an aliphatic cyclic group, and n represents an integer from 1 to 10.]
A resin composition according to an embodiment of the present invention (hereinafter also simply referred to as resin composition) contains a maleimide compound (A) having a benzene ring in the molecule and a hydrocarbon-based compound (B) represented by Formula (1), and the maleimide compound (A) contains a maleimide compound (A-1) having a maleimide group equivalent of 400 g/mol or less.
By containing the hydrocarbon-based compound (B) in addition to the maleimide compound (A), it is possible to provide a resin composition affording a cured product that exhibits low dielectric properties, a high Tg, and rigidity. In particular, from the resin composition of the present embodiment, it is possible to obtain a cured product having a modulus that does not change by changes in temperature as well, that is, a modulus that does not easily decrease during heating as well.
It is preferable that the cured product of the resin composition of the present embodiment has Z2/Z1 of 0.6 or more, where Z1 denotes the storage modulus at 25° C. and Z2 denotes the storage modulus at 260° C. in the dynamic viscoelasticity measurement. It is preferable that Z2/Z1 is more preferably 0.7 or more. By this, it is considered that the above-described properties of rigidity can be exhibited more reliably, and a cured product having a modulus that does not easily decrease during heating as well can be obtained more reliably.
Hence, according to the present embodiment, it is possible to provide a resin composition affording a cured product that exhibits low dielectric properties, a high Tg, and rigidity. By using the resin composition, it is possible to provide a prepreg, a film with resin, a metal foil with resin, a metal-clad laminate, and a wiring board, which exhibit excellent properties.
In the present embodiment, the dynamic viscoelasticity can be measured by using a viscoelasticity spectrometer.
Hereinafter, the respective components of the resin composition according to the present embodiment will be specifically described.
The maleimide compound (A) used in the present embodiment is not particularly limited as long as it is a maleimide compound, which has a benzene ring in the molecule and contains a maleimide compound (A-1) having a maleimide group equivalent of 400 g/mol or less. By using such a maleimide compound, it is possible to obtain a resin composition affording a cured product that exhibits a high Tg and excellent low dielectric properties and rigidity.
In the present embodiment, the maleimide group equivalent means a value obtained by dividing the average molecular weight by the average number of maleimide groups. A more preferable range of maleimide group equivalent is 300 g/mol or less. The lower limit of the maleimide group equivalent is not particularly limited, but is preferably 200 g/mol or more from the viewpoint of compatibility at the time of mixing with the hydrocarbon-based compound (B).
Still more preferably, the maleimide compound (A-1) includes a maleimide compound (A-2) having a benzene ring equivalent of 200 g/mol or less. By this, it is considered that there is an advantage of obtaining a highly rigid resin composition by containing a large number of benzene rings in the molecule.
In the present embodiment, the benzene ring equivalent means a value obtained by dividing the average molecular weight by the average number of benzene rings. A more preferable range of benzene ring equivalent is 150 g/mol or less. The lower limit of the benzene ring equivalent is not particularly limited, but is desirably 50 g/mol or more from the viewpoint of maleimide group equivalent, solubility in solvents, and compatibility at the time of mixing with the hydrocarbon-based compound (B).
In the present embodiment, it is preferable that the maleimide compound (A) dissolves in toluene, methyl ethyl ketone, or a mixed solvent of toluene and methyl ethyl ketone at 40% by mass or more and less than 100% by mass in order to be suitably mixed with the hydrocarbon-based compound (B).
The hydrocarbon-based compound (B) contained in the resin composition of the present embodiment is a compound represented by the following Formula (1).
In Formula (1), X represents a hydrocarbon group having 6 or more carbon atoms and containing at least one selected from an aromatic cyclic group and an aliphatic cyclic group. n represents an integer from 1 to 10.
By containing such a hydrocarbon-based compound (B), it is considered that the resin composition of the present embodiment enables its cured product to attain even lower dielectric properties and keep water absorbing properties low while maintaining a high Tg.
The aromatic cyclic group is not particularly limited, but examples thereof include a phenylene group, a xylylene group, a naphthylene group, a tolylene group, and a biphenylene group.
The aliphatic cyclic group is not particularly limited, but examples thereof include a group containing an indane structure and a group containing a cycloolefin structure.
The number of carbon atoms is not particularly limited as long as it is 6 or more, but is more preferably 6 or more and 20 or less from the viewpoint of maintaining a high Tg.
In a preferred embodiment, the hydrocarbon-based compound of the present embodiment includes a hydrocarbon-based compound (B1) represented by the following Formula (2).
In Formula (2), n represents an integer from 1 to 10.
By containing such a hydrocarbon-based compound (B1), it is considered that the effects as described above can be attained more reliably.
The resin composition according to the present embodiment may contain a reactive compound (C) that reacts with at least one of the maleimide compound (A) and the hydrocarbon-based compound (B), if necessary, as long as the effects of the present invention are not impaired. By containing such a reactive compound (C), it is considered that close contact properties (for example, close contact properties to metal foil) and low thermal expansion properties can be further imparted to the resin composition.
The reactive compound refers to a compound that reacts with at least one of the maleimide compound (A) and the hydrocarbon-based compound (B) and contributes to curing of the resin composition. Examples of the reactive compound (C) include a maleimide compound (D) that does not contain a benzene ring or contains a benzene ring and has a maleimide group equivalent of more than 400 g/mol, an epoxy compound, a methacrylate compound, an acrylate compound, a vinyl compound, a cyanate ester compound, an active ester compound, an allyl compound, a benzoxazine compound, a phenol compound, and a polyphenylene ether compound.
The maleimide compound (D) is not particularly limited as long as it is a maleimide compound different from the maleimide compound (A) described above, which does not contain a benzene ring or contains a benzene ring and has a maleimide group equivalent of more than 400 g/mol, and examples thereof include a maleimide compound that does not have a benzene ring in the molecule or a maleimide compound that has a benzene ring in the molecule and has a maleimide group equivalent of more than 400 g/mol.
As the maleimide compound (D), a commercially available product can also be used, and for example, BMI-5100 and BMI-TMH manufactured by Daiwa Kasei Industry Co., Ltd. and BMI-689, BMI-1500, BMI-3000J, and BMI-5000 manufactured by Designer Molecules Inc. may be used.
The epoxy compound is a compound having an epoxy group in the molecule, and specific examples thereof include a bixylenol-type epoxy compound, a bisphenol A-type epoxy compound, a bisphenol F-type epoxy compound, a bisphenol S-type epoxy compound, a bisphenol AF-type epoxy compound, a dicyclopentadiene-type epoxy compound, a trisphenol-type epoxy compound, a naphthol novolac-type epoxy compound, a phenol novolac-type epoxy compound, a tert-butyl-catechol-type epoxy compound, a naphthalene-type epoxy compound, a naphthol-type epoxy compound, an anthracene-type epoxy compound, a glycidylamine-type epoxy compound, a glycidyl ester-type epoxy compound, a cresol novolac-type epoxy compound, a biphenyl-type epoxy compound, a linear aliphatic epoxy compound, an epoxy compound having a butadiene structure, an alicyclic epoxy compound, a heterocyclic epoxy compound, a spiro ring-containing epoxy compound, a cyclohexane-type epoxy compound, a cyclohexanedimethanol-type epoxy compound, a naphthylene ether-type epoxy compound, a trimethylol-type epoxy compound, and a tetraphenylethane-type epoxy compound. The epoxy compound also includes an epoxy resin, which is a polymer of each of the epoxy compounds.
The methacrylate compound is a compound having a methacryloyl group in the molecule, and examples thereof include a monofunctional methacrylate compound having one methacryloyl group in the molecule and a poly functional methacrylate compound having two or more methacryloyl groups in the molecule. Examples of the monofunctional methacrylate compound include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. Examples of the polyfunctional methacrylate compound include dimethacrylate compounds such as tricyclodecanedimethanol dimethacrylate (DCP).
The acrylate compound is a compound having an acryloyl group in the molecule, and examples thercof include a monofunctional acrylate compound having one acryloyl group in the molecule and a polyfunctional acrylate compound having two or more acryloyl groups in the molecule. Examples of the monofunctional acrylate compound include methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. Examples of the polyfunctional acrylate compound include diacrylate compounds such as tricyclodecanedimethanol diacrylate.
The vinyl compound is a compound having a vinyl group in the molecule, and examples thereof include a monofunctional vinyl compound (monovinyl compound) having one vinyl group in the molecule and a polyfunctional vinyl compound having two or more vinyl groups in the molecule. Examples of the polyfunctional vinyl compound include divinylbenzene, curable polybutadiene having a carbon-carbon unsaturated double bond in the molecule, and a curable butadiene-styrene copolymer having a carbon-carbon unsaturated double bond in the molecule.
The cyanate ester compound is a compound having a cyanato group in the molecule, and examples thereof include a phenol novolac-type cyanate ester compound, a naphthol aralkyl-type cyanate ester compound, a biphenyl aralkyl-type cyanate ester compound, a naphthylene ether-type cyanate ester compound, a xylene resin-type cyanate ester compound, and an adamantane skeleton-type cyanate ester compound.
The active ester compound is a compound having an ester group exhibiting high reaction activity in the molecule, and examples thereof include a benzenecarboxylic acid active ester, a benzenedicarboxylic acid active ester, a benzenetricarboxylic acid active ester, a benzenetetracarboxylic acid active ester, a naphthalenecarboxylic acid active ester, a naphthalenedicarboxylic acid active ester, a naphthalenetricarboxylic acid active ester, a naphthalenetetracarboxylic acid active ester, a fluorenecarboxylic acid active ester, a fluorenedicarboxylic acid active ester, a fluorenetricarboxylic acid active ester, and a fluorenetetracarboxylic acid active ester.
The allyl compound is a compound having an allyl group in the molecule, and examples thereof include a triallyl isocyanurate compound such as triallyl isocyanurate (TAIC), a diallyl bisphenol compound, and diallyl phthalate (DAP).
As the benzoxazine compound, for example, a benzoxazine compound represented by the following General Formula (C-I) can be used.
In Formula (C-1), R1 represents a k-valent group, and each R2 independently represents a halogen atom, an alkyl group, or an aryl group. k represents an integer from 2 to 4 and I represents an integer from 0 to 4.
Commercially available products include “JBZ-OP100D” and “ODA-BOZ” manufactured by JFE Chemical Corporation; “P-d”, “F-a” and “ALP-d” manufactured by SHIKOKU CHEMICALS CORPORATION, and “HFB2006M” manufactured by Showa Highpolymer Co., Ltd. and the like.
As the phenol compound, a compound containing a hydroxy group bonded to an aromatic ring in the molecule can be used, and examples thereof include a bisphenol A-type phenol compound, a bisphenol E-type phenol compound, a bisphenol F-type phenol compound, a bisphenol S-type phenol compound, a phenol novolac compound, a bisphenol A novolac-type phenol compound, a glycidyl ester-type phenol compound, an aralkyl novolac-type phenol compound, a biphenylaralkyl-type phenol compound, a cresol novolac-type phenol compound, a polyfunctional phenol compound, a naphthol compound, a naphthol novolac compound, a polyfunctional naphthol compound, an anthracene-type phenol compound, a naphthalene skeleton-modified novolac-type phenol compound, a phenol aralkyl-type phenol compound, a naphtholaralkyl-type phenol compound, a dicyclopentadiene-type phenol compound, a biphenyl-type phenol compound, an alicyclic phenol compound, a polyol-type phenol resin, a phosphorus-containing phenol compound, a polymerizable unsaturated hydrocarbon group-containing phenol compound, and a hydroxyl group-containing silicone compound.
The polyphenylene ether compound can be synthesized by a known method, or a commercially available product can be used. Examples of the commercially available product include “OPE-2st 1200” and “OPE-2st 2200” manufactured by Mitsubishi Gas Chemical Company Inc., and “SA9000”, “SA90”, “SA120” and “Noryl640” manufactured by SABIC Innovative Plastics.
As the reactive compound (C), the compounds mentioned above may be used singly or in combination of two or more kinds thereof.
In the resin composition of the present embodiment, the content of the maleimide compound (A) is preferably 20 to 80 parts by mass with respect to 100 parts by mass of the total mass of the maleimide compound (A) and the hydrocarbon-based compound (B). When the content is in such a range, it is considered that the effects of the present invention as described above can be attained more reliably. A more preferable range of the content is 30 parts by mass or more and 70 parts by mass or less.
In a case where the resin composition of the present embodiment contains the reactive compound (C), the content of the hydrocarbon-based compound (B) is preferably 5 to 50 parts by mass, more preferably 20 to 50 parts by mass with respect to 100 parts by mass of the sum of the maleimide compound (A), the hydrocarbon-based compound (B), and the reactive compound (C).
In that case, the content of the reactive compound (C) is preferably 1 to 40 parts by mass, more preferably 1 to 30 parts by mass with respect to 100 parts by mass of the sum of the maleimide compound (A), the hydrocarbon-based compound (B), and the reactive compound (C).
The resin composition according to the present embodiment may further contain an inorganic filler. The inorganic filler is not particularly limited and includes those added to enhance the heat resistance and flame retardancy of the cured product of a resin composition. By containing an inorganic filler, it is considered that heat resistance, flame retardancy and the like can be further enhanced as well as the coefficient of thermal expansion can be kept lower (achievement of even lower thermal expansion properties).
Specific examples of the inorganic filler that can be used in the present embodiment include metal oxides such as silica, alumina, titanium oxide, magnesium oxide, and mica, metal hydroxides such as magnesium hydroxide and aluminum hydroxide, talc, aluminum borate, barium sulfate. aluminum nitride, boron nitride, barium titanate, strontium titanate, calcium titanate, aluminum titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, zirconium tungstate phosphate, magnesium carbonate such as anhydrous magnesium carbonate, calcium carbonate, and boehmite-treated products thereof. Among these, silica, metal hydroxides such as magnesium hydroxide and aluminum hydroxide, aluminum oxide, boron nitride, and barium titanate, strontium titanate and the like are preferable, and silica is more preferable. The silica is not particularly limited, and examples thereof include crushed silica, spherical silica, and silica particles.
These inorganic fillers may be used singly or in combination of two or more kinds thereof. An inorganic filler as described above may be used as it is, but one subjected to a surface treatment with an epoxysilane-type, vinylsilane-type, methacrylsilane-type, phenylaminosilane-type, or aminosilane-type silane coupling agent may be used. The silane coupling agent can be used by being added to the filler by an integral blend method instead of the method of treating the surface of the filler with the silane coupling agent in advance.
In a case where the resin composition of the present embodiment contains an inorganic filler, the content of the inorganic filler is preferably 10 to 300 parts by mass, more preferably 40 to 250 parts by mass with respect to 100 parts by mass of the total mass of the maleimide compound (A) and the hydrocarbon-based compound (B).
The resin composition according to the present embodiment may further contain a flame retardant. The flame retardancy of a cured product of the resin composition can be further enhanced by containing a flame retardant.
The flame retardant that can be used in the present embodiment is not particularly limited. Specifically, in the field in which halogen-based flame retardants such as bromine-based flame retardants are used, for example, ethylenedipentabromobenzene, ethylenebistetrabromoimide, decabromodiphenyloxide, and tetradccabromodiphenoxybenzene which have a melting point of 300° C. or more are preferable. It is considered that the elimination of halogen at a high temperature and the decrease in heat resistance can be suppressed by the use of a halogen-based flame retardant. There is a case where a flame retardant containing phosphorus (phosphorus-based flame retardant) is used in fields required to be halogen-free. The phosphorus-based flame retardant is not particularly limited, and examples thereof include an HCA-based flame retardant, a phosphate ester-based flame retardant, a phosphazene-based flame retardant, a bis(diphenylphosphine oxide)-based flame retardant, and a phosphinate-based flame retardant. Specific examples of the HCA-based flame retardant include 9,10-dihydro-9-oxa-10-phosphaphenanthren-10-yl-10-oxide, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, or compounds obtained by reacting these in advance. Specific examples of the phosphate ester-based flame retardant include a condensed phosphate ester such as dixylenyl phosphate. Specific examples of the phosphazene-based flame retardant include phenoxyphosphazene. Specific examples of the bis (diphenylphosphine oxide)-based flame retardant include xylylenebis (diphenylphosphine oxide). Specific examples of the phosphinate-based flame retardant include metal phosphinates such as an aluminum dialkyl phosphinate. As the flame retardant, the respective flame retardants exemplified may be used singly or in combination of two or more kinds thercof.
In a case where the resin composition of the present embodiment contains a flame retardant, the content of the flame retardant is preferably 3 to 50 parts by mass, more preferably 5 to 40 parts by mass with respect to 100 parts by mass of the total mass of the resin composition except for the inorganic filler.
The resin composition according to the present embodiment may contain components (other components) other than the components described above if necessary as long as the effects of the present invention are not impaired. As the other components contained in the resin composition according to the present embodiment, for example, additives such as catalysts including a reaction initiator and a reaction accelerator, a silane coupling agent, a polymerization inhibitor, a polymerization retardant, an auxiliary flame retardant, an antifoaming agent, a leveling agent, an antioxidant, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a dye or a pigment, a dispersant, and a lubricant may be further contained.
The resin composition according to the present embodiment may contain a reaction initiator (catalyst) and a reaction accelerator as described above. The reaction initiator and reaction accelerator are not particularly limited as long as they can promote the curing reaction of the resin composition. Specifically, examples thereof include metal oxides, azo compounds, peroxides, imidazole compounds, phosphorus-based curing accelerators, and amine-based curing accelerators.
Specific examples of metal oxides include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.
Examples of peroxides include α,α′-di(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, benzoyl peroxide, 3,3′,5,5′-tetramethyl-1,4-diphenoquinone, chloranil, 2,4,6-tri-t-butylphenoxyl, t-butylperoxyisopropyl monocarbonate, and azobisisobutyronitrile.
Specific examples of azo compounds include 2,2′-azobis(2,4,4-trimethylpentane), 2,2′-azobis(N-butyl-2-methylpropionamide), and 2,2′-azobis(2-methylbutyronitrile).
Among these, α,α′-di(t-butylperoxy)diisopropylbenzene is preferably used as a preferable reaction initiator. α,α′-Di(t-butylperoxy)diisopropylbenzene exhibits low volatility, thus does not volatilize at the time of drying and storage, and exhibits favorable stability. α,α′-Di(t-butylperoxy)diisopropylbenzene has a relatively high reaction initiation temperature and thus can suppress the promotion of the curing reaction at the time point at which curing is not required, for example, at the time of prepreg drying. By suppressing the curing reaction, it is possible to suppress a decrease in storage stability of the resin composition.
Examples of phosphorus-based curing accelerators include triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate.
Examples of amine-based curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridinc (DMAP), benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene.
Examples of imidazole-based compounds include imidazole compounds such as 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2′-methylimidazolyl-(1′)]-ethyl-s-triazine, 2,4-diamino-6-[2′-undecylimidazolyl-(1′)]-ethyl-s-triazine, 2,4-diamino-6-[2′-ethyl-4′-methylimidazolyl-(1′)]-ethyl-s-triazine, 2,4-diamino-6-[2′-methylimidazoly]-(1′)-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazolinc, and 2-phenylimidazoline.
The reaction initiators as described above may be used singly or in combination of two or more kinds thereof.
In a case where the resin composition of the present embodiment contains the reaction initiator, the content of the reaction initiator is not particularly limited, but is, for example, preferably 0.01 to 5.0 parts by mass, more preferably 0.01 to 3 parts by mass, still more preferably 0.05 to 3.0 parts by mass with respect to 100 parts by mass of the sum of the maleimide compound (A) and the hydrocarbon-based compound (B) (and the reactive compound (C) in a case of containing the reactive compound (C)).
Next, a prepreg for wiring board, a metal-clad laminate, a wiring board, and a metal foil with resin obtained using the resin composition of the present embodiment will be described. The respective symbols in the drawings indicate the following: 1 prepreg, 2 resin composition or semi-cured product of resin composition, 3 fibrous base material, 11 metal-clad laminate, 12 insulating layer, 13 metal foil, 14 wiring, 21 wiring board, 31 metal foil with resin, 32, 42 resin layer, 41 film with resin, and 43 support film.
As illustrated in
In the present embodiment, the “semi-cured product” is one in a state in which the resin composition is partly cured so as to be further cured. In other words, the semi-cured product is the resin composition in a semi-cured state (B-staged). For example, when a resin composition is heated, the viscosity of the resin composition first gradually decreases, then curing starts, and the viscosity gradually increases. In such a case, the semi-cured state includes a state in which the viscosity has started to increase but curing is not completed, and the like.
The prepreg to be obtained using the resin composition according to the present embodiment may include a semi-cured product of the resin composition as described above or include the uncured resin composition itself. In other words, the prepreg may be a prepreg including a semi-cured product of the resin composition (the resin composition in B stage) and a fibrous base material, or may be a prepreg including the resin composition before curing (the resin composition in A stage) and a fibrous base material. Specific examples of the prepreg include those in which a fibrous base material is present in the resin composition. The resin composition or semi-cured product thereof may be one obtained by heating and drying the resin composition.
When the prepreg and the metal foil with resin, metal-clad laminate and the like to be described later are fabricated, the resin composition according to the present embodiment is often prepared in the form of a varnish and used as a resin varnish. Such a resin varnish is prepared, for example, as follows.
First, the respective components that can be dissolved in an organic solvent, such as a resin component and a reaction initiator, are put into an organic solvent and dissolved. At this time, heating may be performed if necessary. Thereafter, an inorganic filler and the like, which are components that do not dissolve in an organic solvent, are added to and dispersed in the solution until a predetermined dispersion state is achieved using a ball mill, a bead mill, a planetary mixer, a roll mill or the like, whereby a varnish-like resin composition is prepared. The organic solvent used here is not particularly limited as long as it dissolves the maleimide compound (A), the hydrocarbon-based compound (B), and if necessary, the reactive compound (C) and the like and does not inhibit the curing reaction. Specific examples thereof include toluene, methyl ethyl ketone, cyclohexanone, cyclopentanone, methylcyclohexane, dimethylformamide, and propylene glycol monomethyl ether acetate. These may be used singly or two or more kinds thereof may be used concurrently.
Examples of the method for fabricating the prepreg 1 of the present embodiment using the varnish-like resin composition of the present embodiment include a method in which the fibrous base material 3 is impregnated with the resin composition 2 in the form of a resin varnish and then drying is performed.
Specific examples of the fibrous base material used in fabrication of the prepreg include glass cloth, aramid cloth, polyester cloth, LCP (liquid crystal polymer) nonwoven fabric, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. When glass cloth is used, a laminate exhibiting excellent mechanical strength is obtained, and glass cloth subjected to flattening is particularly preferable. The glass cloth used in the present embodiment is not particularly limited, but examples thereof include glass cloth with low dielectric constant such as E glass, S glass, NE glass, Q glass, and L glass. Specifically, the flattening can be carried out, for example, by continuously pressing the glass cloth with press rolls at an appropriate pressure to flatten the yarn. As for the thickness of the fibrous base material, for example, a fibrous base material having a thickness of 0.01 to 0.3 mm can be generally used.
Impregnation of the fibrous base material 3 with the resin varnish (resin composition 2) is performed by dipping, coating, or the like. This impregnation can be repeated multiple times if necessary. At this time, it is also possible to repeat impregnation using a plurality of resin varnishes having different compositions and concentrations, and adjust the composition (content ratio) and resin amount to the finally desired values.
The fibrous base material 3 impregnated with the resin varnish (resin composition 2) is heated under desired heating conditions, for example, at 80° C. or more and 180° C. or less for 1 minute or more and 10 minutes or less. By heating, the solvent is volatilized from the varnish and the solvent is diminished or removed to obtain the prepreg 1 before curing (in A stage) or in a semi-cured state (B stage).
As illustrated in
Examples of the method for fabricating such a metal foil with resin 31 include a method in which a resin composition in the form of a resin varnish as described above is applied to the surface of the metal foil 13 such as a copper foil and then dried. Examples of the coating method include a bar coater, a comma coater, a die coater, a roll coater, and a gravure coater.
As the metal foil 13, metal foils used in metal-clad laminates, wiring boards and the like can be used without limitation, and examples thercof include copper foil and aluminum foil. As illustrated in
As the method for fabricating such a film with resin 41, for example, a resin composition in the form of a resin varnish as described above is applied to the surface of the film supporting base material 43, and then the solvent is volatilized from the varnish and diminished or removed, whereby a film with resin before curing (A stage) or in a semi-cured state (B stage) can be obtained.
Examples of the film supporting base material include electrical insulating films such as a polyimide film, a PET (polyethylene terephthalate) film, a polyethylene naphthalatc film, a polyester film, a poly(parabanic acid) film, a polyether ether ketone film, a polyphenylene sulfide film, an aramid film, a polycarbonate film, and a polyarylate film.
In the film with resin and metal foil with resin of the present embodiment, the resin composition or semi-cured product thereof may be one obtained by drying or heating and drying the resin composition as in the prepreg described above.
The thickness and the like of the metal foil 13 and the film supporting base material 43 can be appropriately set depending on the desired purpose. For example, as the metal foil 13, a metal foil having a thickness of about 0.2 to 70 μm can be used. In a case where the thickness of metal foil is, for example, 10 μm or less, the metal foil may be a carrier-attached copper foil including a release layer and a carrier in order to improve handleability. The application of the resin varnish to the metal foil 13 and the film supporting base material 43 is performed by coating or the like, and this can be repeated multiple times if necessary. At this time, it is also possible to repeat coating using a plurality of resin varnishes having different compositions and concentrations, and adjust the composition (content ratio) and resin amount to the finally desired values.
Drying or heating and drying conditions in the fabrication method of the metal foil with resin 31 and film with resin 41 are not particularly limited, but a resin composition in the form of a resin varnish is applied to the metal foil 13 and film supporting base material 43, and then heating is performed under desired heating conditions, for example, at 50° C. to 180° C. for about 0.1 to 10 minutes to volatilize the solvent from the varnish and diminish or remove the solvent, whereby the metal foil with resin 31 and film with resin 41 before curing (A stage) or in a semi-cured state (B stage) are obtained.
The metal foil with resin 31 and film with resin 41 may include a cover film and the like, if necessary. By including a cover film, it is possible to prevent foreign matter from entering. The cover film is not particularly limited as long as it can be peeled off without damaging the form of the resin composition, and for example, a polyolefin film, a polyester film, a TPX film, films formed by providing a mold releasing agent layer on these films, and paper obtained by laminating these films on a paper base material can be used.
As illustrated in
The metal-clad laminate 11 of the present embodiment can also be fabricated using the resin-coated metal foil 31 or resin film 41 described above.
As the method for fabricating a metal-clad laminate using the prepreg 1, metal foil with resin 31, or resin film 41 obtained in the manner described above, one or a plurality of prepregs 1, metal foils with resin 31, or resin films 41 are superimposed on one another, and the metal foils 13 such as copper foil are further superimposed on both upper and lower sides or on one side, and this is laminated and integrated by heating and pressing, whereby a double-sided metal-clad or single-sided metal-clad laminate can be fabricated. The heating and pressing conditions can be appropriately set depending on the thickness of the laminate to be fabricated, the kind of the resin composition, and the like, but for example, the temperature may be set to 170° C. to 230° C., the pressure may be set to 1.5 to 5.0 MPa, and the time may be set to 60 to 150 minutes.
The metal-clad laminate 11 may be fabricated by forming a film-like resin composition on the metal foil 13 without using the prepreg 1 or the like and performing heating and pressing.
As illustrated in
The resin composition of the present embodiment is suitably used as a material for an insulating layer of a wiring board. As the method for fabricating the wiring board 21, for example, the metal foil 13 on the surface of the metal-clad laminate 11 obtained above is etched to form a circuit (wiring), whereby the wiring board 21 having a conductor pattern (wiring 14) provided as a circuit on the surface of a laminate can be obtained. Examples of the circuit forming method include circuit formation by a semi additive process (SAP) or a modified semi additive process (MSAP) in addition to the method described above.
The prepreg, film with resin, and metal foil with resin obtained using the resin composition of the present embodiment are extremely useful in industrial applications since the cured products thereof exhibit excellent low dielectric properties and high Tg as well as suppressed water absorbing properties. The metal-clad laminate and wiring board obtained by curing these have advantages of exhibiting low dielectric properties and a high Tg and of being able to suppress moisture absorption.
The prepreg, film with resin, and metal foil with resin obtained using the resin composition of the present embodiment are extremely useful in industrial applications since the cured products thereof exhibit a high Tg and excellent low dielectric properties and rigidity. The metal-clad laminate and wiring board obtained by curing these have the advantages of a high Tg and excellent low dielectric properties and rigidity.
Hereinafter, the present invention will be described more specifically with reference to Examples, but the scope of the present invention is not limited thereto.
First, the components to be used in the preparation of resin compositions in the following examples will be described.
First, into a 1-L flask equipped with a thermometer, a condenser, a Dean-Stark tube, and a stirrer, 48.5 g (0.4 mol) of 2,6-dimethylaniline, 272.0 g (1.4 mol) of α,α′-dihydroxy-1,3-diisopropylbenzene, 280 g of xylene, and 70 g of activated clay were introduced and heated to 120° C. while being stirred. Further, the temperature was raised to 210° C. while removing the distilled water through the Dean-Stark tube. By doing so, the reaction was conducted for 6 hours. After that, the reaction mixture was cooled to 140° C., 145.4 g (1.2 mol) of 2,6-dimethylaniline was introduced, and then the temperature was raised to 220° C. By doing so, the reaction was conducted for 3 hours. After the reaction, the reaction mixture was air-cooled to 100° C., and diluted with 300 g of toluene, and activated clay was removed by filtration, and low molecular weight substances such as the solvent and unreacted substances were distilled off under reduced pressure, thereby obtaining 345.2 g of a solid. The obtained solid was an amine compound (amine equivalent: 348, softening point: 71° C.) represented by the following Formula (3).
Next, 131.8 g (1.3 mol) of maleic anhydride and 700 g of toluene were introduced into a 2-L flask equipped with a thermometer, a condenser, a Dean-Stark tube, and a stirrer, and stirred at room temperature. After that, a mixed solution of 345.2 g of the amine compound represented by Formula (3) and 175 g of DMF was added dropwise over 1 hour. After completion of the dropwise addition, the mixture was further stirred at room temperature for 2 hours to conduct the reaction. After that, 37.1 g of p-toluenesulfonic acid monohydrate was added, the reaction solution was heated, and the azeotropic water and toluene were cooled and separated under reflux, and then only toluene was returned to the system, thereby conducting the dehydration reaction for 8 hours. After air-cooling to room temperature, the reaction mixture was concentrated under reduced pressure, the brown solution was dissolved in 600 g of ethyl acetate and washed with 150 g of deionized water three times and 150 g of 2% aqueous sodium bicarbonate solution three times, sodium sulfate was added for drying, then concentration was performed under reduced pressure, and the obtained reaction product was vacuum-dried at 80° C. for 4 hours, thereby obtaining 407.6 g of a solid. The obtained solid was analyzed by FD-MS spectrum, GPC and the like, and was found to be a maleimide compound in which the amine of the amine compound represented by Formula (3) was modified with a maleimide (benzene ring equivalent: 153 g/mol, maleimide equivalent: 428 g/mol).
First, the weight average molecular weight (Mw) and number average molecular weight (Mn) used in the production of hydrocarbon-based compound 1 below are values determined by the following analysis method.
The molecular weights were calculated in terms of polystyrene using a polystyrene standard solution.
GPC: DGU-20A3R, LC-20AD, SIL-20AHT, RID-20A, SPD-20A, CTO-2, CBM-20A (all manufactured by Shimadzu Corporation)
Into a flask equipped with a thermometer, a condenser, and a stirrer, 296 parts of 2-bromoethylbenzene (manufactured by Tokyo Chemical Industry Co., Ltd.), 70 parts of α,α′-dichloro-p-xylene (manufactured by Tokyo Chemical Industry Co., Ltd.), and 18.4 parts of methanesulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) were introduced, and the reaction was conducted at 130° C. for 8 hours. After being left to cool, the reaction mixture was neutralized with an aqueous sodium hydroxide solution, and subjected to extraction with 1200 parts of toluene, and the organic layer was washed with 100 parts of water five times. The solvent and excess 2-bromoethylbenzene were distilled off under heating and reduced pressure to obtain 160 parts of an olefin compound precursor (BEB-1) having a 2-bromoethylbenzene structure as a liquid resin (Mn: 538, Mw: 649). A GPC chart of the obtained compound is illustrated in
Next, 22 parts of BEB-1 obtained in Synthesis Example 1, 50 parts of toluene, 150 parts of dimethyl sulfoxide, 15 parts of water and 5.4 parts of sodium hydroxide were introduced into a flask equipped with a thermometer, a condenser, and a stirrer, and the reaction was conducted at 40° C. for 5 hours. After standing to cool, 100 parts of toluene was added, the organic layer was washed with 100 parts of water five times, and the solvent was distilled off under heating and reduced pressure to obtain 13 parts of a liquid olefin compound having a styrene structure as a functional group (Mn: 432, Mw: 575). A GPC chart of the obtained compound is illustrated in
The liquid olefin compound was referred to as hydrocarbon-based compound 1.
First, the respective components, that is, resin components (maleimide compound, hydrocarbon-based compound, and the like) were added to a toluene solvent at the blending proportion (parts by mass) presented in Table 1 described later so that the solid concentration was 50% by mass, and stirred for 60 minutes, and then dispersed using a bead mill to obtain resin varnishes of the respective Examples and Comparative Examples.
First, the varnish obtained above was impregnated into a fibrous base material (glass cloth: #2116 type, L Glass manufactured by Asahi Kasei Corporation) and then heated and dried at 120° C. for 3 minutes, thereby fabricating a prepreg having a thickness of 125 μm. At that time, the content (resin content) of the components constituting the resin composition with respect to the prepreg was adjusted to be about 50% by mass by the curing reaction.
Next, an evaluation substrate (metal-clad laminate) was obtained as follows.
Two sheets of each of the obtained prepregs were stacked, and copper foil (FV-WS manufactured by Furukawa Electric Co., Ltd., thickness: 18 μm) was disposed on both sides of the stacked body. This as a body to be pressed was heated to a temperature of 220° C. at a rate of temperature rise of 3° C./min and heated and pressed under the conditions of 220° C., 120 minutes, and a pressure of 2 MPa, thereby obtaining an evaluation substrate (metal-clad laminate) having copper foil bonded to both surfaces and having a resin layer thickness of about 250 μm.
The evaluation substrates (metal-clad laminates) fabricated as described above were used to conduct evaluation tests by the following methods.
Using an unclad substrate obtained by removing the copper foil from the evaluation substrate obtained above by etching, Tg was measured using a viscoelastic spectrometer “DMS100” manufactured by Seiko Instruments Inc. At this time, dynamic viscoelasticity measurement (DMA) was performed with a tensile module at a frequency of 10 Hz, and the temperature at which tan δ was maximized when the temperature was raised from room temperature to 300° C. at a rate of temperature rise of 5° C./min was taken as Tg. In this test, it is determined as acceptable when the Tg is 260° C. or more.
Z2/Z1 was taken as the modulus ratio, where Z1 denoted the storage modulus at 25° C. and Z2 denoted the storage modulus at 260° C. In this test, it is determined as acceptable when the modulus ratio is 0.6 or more.
The relative dielectric constant and dielectric loss tangent at 10 GHz were measured by the cavity perturbation method using an unclad substrate obtained by removing the copper foil from the evaluation substrate (metal-clad laminate) by etching as a test piece. Specifically, the relative dielectric constant and dielectric loss tangent of the evaluation substrate at 10 GHz were measured using a network analyzer (N5230A manufactured by Keysight Technologies). In this test, it is determined as acceptable when Dk is 3.5 or less and Df is 0.003 or less.
The results are presented in Table 1.
As is clear from the results in Table 1, it was found that the cured products of the resin compositions in Examples of the present invention all exhibit a high Tg, low dielectric properties, and excellent rigidity.
On the other hand, the cured product in Comparative Example 1, which does not contain the maleimide compound (A) of the present invention, exhibits a low Tg and insufficient rigidity. The cured product in Comparative Example 2, which does not contain the hydrocarbon-based compound (B) of the present invention, is inferior in rigidity. In Comparative Example 3 in which a maleimide compound having an indane skeleton used in the prior art is contained instead of the maleimide compound (A) of the present invention as well, the cured product does not exhibit sufficient rigidity.
This application is based on Japanese Patent Application No. 2021-83149 filed on May 17, 2021, the contents of which are included in the present application.
In order to express the present invention, the present invention has been described above appropriately and sufficiently through the embodiments with reference to specific examples, drawings and the like. However, it should be recognized by those skilled in the art that changes and/or improvements of the above-described embodiments can be readily made. Accordingly, changes or improvements made by those skilled in the art shall be construed as being included in the scope of the claims unless otherwise the changes or improvements are at the level which departs from the scope of the appended claims.
The present invention has wide industrial applicability in technical fields such as electronic materials, electronic devices, and optical devices.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-083149 | May 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/020371 | 5/16/2022 | WO |
