Thermosetting resin composition, prepreg comprising same, metal foil laminate, laminate sheet, and printed circuit board

Abstract

The present invention relates to: a thermosetting resin composition containing (a) a modified polyphenylene ether having an unsaturated substituent at least at one end of a molecular chain, (b) two or more curing agents, and (c) a flame retardant, and a prepreg, a metal foil laminate, a laminate sheet, and a printed circuit board comprising the same, the two or more curing agents include (b1) a hydrogenated polybutadiene and (b2) a (hydrogenated) aromatic vinyl compound-conjugated diene copolymer.

Description

Technical Field

[0001] The present invention relates to thermosetting resin compositions having low dielectric properties and high heat resistance properties, as well as prepregs, metal foil laminates, laminates and printed circuit boards containing the same. Background Technology

[0002] In recent years, with the advent of the era of hyper-connected intelligence, including artificial intelligence, big data, and autonomous vehicles, the development and popularization of various electronic devices such as smartphones have accelerated. This has led to the comprehensive development of next-generation 5G communication, capable of transmitting large amounts of data wirelessly at high speeds, replacing existing 4G LTE communication. In particular, for the widespread adoption of autonomous vehicles, smart cities, and smart factories, next-generation 5G communication technology, capable of connecting and processing large amounts of data in real time without latency, has become essential. 5G operates at high frequencies (above 26 GHz), specifically millimeter-wave (mmWave) 5G, enabling the transmission of large amounts of data at once and ensuring high-precision images with high resolution. However, the higher the frequency band used by communication / electronic devices, the greater the transmission loss of electrical signals, which may lead to problems such as overheating, signal attenuation, and latency.

[0003] Therefore, in the past, materials with low dielectric constants and low dielectric loss tangents have been developed to reduce transmission losses. For example, polyphenylene ether resins have been modified by substituents on the unsaturated bonds on both sides of the molecular chain, or liquid crystal polymers (LCPs) or modified polyimides (MPIs) suitable for high-frequency bands have been applied to printed circuit boards. However, these methods have limitations such as poor heat resistance or adhesion to copper foil, and difficulties in improving dielectric properties. Summary of the Invention

[0004] Technical issues

[0005] The present invention aims to provide a thermosetting resin composition with excellent heat resistance and low dielectric properties.

[0006] In addition, the present invention aims to use the above-mentioned thermosetting resin composition to provide prepregs, metal foil laminates, laminates and printed circuit boards that can be used in the high frequency to ultra-high frequency band.

[0007] Methods for solving problems

[0008] To achieve the above objectives, the present invention provides a high-frequency thermosetting resin composition comprising (a) a modified polyphenylene ether having an unsaturated substituent at at least one end of the molecular chain, (b) two or more curing agents, and (c) a flame retardant, wherein the two or more curing agents comprise (b1) hydrogenated polybutadiene and (b2) (hydrogenated) aromatic vinyl compound-conjugated diene copolymer.

[0009] According to one example, the aforementioned hydrogenated polybutadiene can have a hydrogenation rate in the range of 80% to 99%.

[0010] According to another example, in the above-mentioned (hydrogenated) aromatic vinyl compound-conjugated diene copolymer, the hydrogenated aromatic vinyl compound-conjugated diene copolymer can have a hydrogenation rate in the range of 60% to 85%.

[0011] According to yet another example, the two or more curing agents mentioned above may further include curing agents.

[0012] According to another example, based on 100% by weight of the above-mentioned thermosetting resin composition, the content of the two or more curing agents can be in the range of 5% to 25% by weight.

[0013] According to yet another example, the above-mentioned thermosetting resin composition may further comprise one or more selected from the group consisting of inorganic fillers, initiators and curing accelerators.

[0014] In addition, the present invention provides a prepreg comprising the above-described thermosetting resin composition.

[0015] In addition, the present invention provides a metal foil laminate comprising the above-described thermosetting resin composition.

[0016] Furthermore, the present invention provides a laminate comprising a polymer film and a resin layer disposed on at least one side of the polymer film and composed of the thermosetting resin composition.

[0017] Furthermore, the present invention provides a printed circuit board comprising the above-described thermosetting resin composition.

[0018] Invention Effects

[0019] The thermosetting resin composition of the present invention has a high glass transition temperature (Tg), low dielectric constant and dielectric loss tangent, and excellent resin flowability. Therefore, it has excellent processability when applied to printed circuit boards, and can improve the low dielectric loss and heat resistance of printed circuit boards.

[0020] Therefore, the thermosetting resin composition of the present invention can be effectively used in components of printed circuit boards used in mobile communication devices or their base station devices, network-related electronic devices such as servers and routers, and various electrical and electronic devices such as large computers that process high-frequency signals above 1 GHz. Detailed Implementation

[0021] The present invention will now be described.

[0022] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) are to be used in the sense that would be commonly understood by one of ordinary skill in the art to which this invention pertains. Furthermore, unless explicitly defined otherwise, terms as defined in commonly used dictionaries are not to be interpreted ideally or excessively.

[0023] Furthermore, throughout the specification, when it is stated that a certain part "contains" a certain component, unless there is a specific statement to the contrary, it should be understood as an open-ended term that covers other components rather than excluding them.

[0024] Furthermore, throughout the instruction manual, the term "above" or "on top" refers not only to the case where it is located directly above or below the object part, but also to the case where there are other parts in between, and does not necessarily mean that it is located on the upper side based on the direction of gravity.

[0025] Furthermore, in this application specification, terms such as "first" and "second" do not indicate any arbitrary order or importance, but are used to distinguish the constituent elements from each other.

[0026] <Thermosetting Resin Composition>

[0027] The thermosetting resin composition of the present invention is a high-frequency non-epoxy thermosetting resin composition applicable to printed circuit boards, particularly printed circuit boards usable in the high-frequency to ultra-high-frequency band. It comprises (a) a modified polyphenylene ether having at least one unsaturated substituent at the end of its molecular chain, (b) two or more curing agents, and (c) a flame retardant, wherein the two or more curing agents comprise (b1) hydrogenated polybutadiene and (b2) a (hydrogenated) aromatic vinyl compound-conjugated diene copolymer. Furthermore, the thermosetting resin composition may further comprise one or more selected from the group consisting of curing accelerators, initiators, and fillers.

[0028] The components of the thermosetting resin composition of the present invention will be described below.

[0029] (a) Modified polyphenylene ether

[0030] The thermosetting resin composition of the present invention comprises modified polyphenylene ether (PPE).

[0031] The modified polyphenylene ether described above has two or more unsaturated substituents (e.g., vinyl, allyl, or both) at at least one end of the molecular chain, and its structure can be used without particular restrictions.

[0032] As an example, the modified polyphenylene ether described above can be a polyphenylene ether having two or more vinyl groups at both ends of the molecular chain.

[0033] As another example, the modified polyphenylene ether described above can be represented by the following chemical formula 1. The two ends of such a modified polyphenylene ether can be modified with two or more vinyl groups. Therefore, the resin composition of the present invention not only has a high glass transition temperature and a low coefficient of thermal expansion, but also improves moisture resistance and dielectric properties due to the reduction of -OH groups.

[0034] [Chemical Formula 1]

[0035]

[0036] In the above chemical formula 1,

[0037] Y is one or more compounds selected from the group consisting of bisphenol A, bisphenol F, bisphenol S, naphthalene, anthracene, biphenyl, tetramethylbiphenyl, phenolic varnish, cresol varnish, bisphenol A varnish, and bisphenol S varnish.

[0038] m and n are each independent natural numbers from 3 to 20.

[0039] The modified polyphenylene ether of the present invention is obtained by redistribution reaction to modify high molecular weight polyphenylene ether to low molecular weight, and then modifying the alcohol groups located at both ends with low polarity unsaturated substituents (e.g., vinyl, allyl). Since the molecular weight is smaller than that of conventional polyphenylene ether, the flowability of the resin composition can be improved, and low dielectric loss characteristics can also be achieved after crosslinking.

[0040] In particular, during the aforementioned redistribution reaction, high-molecular-weight polyphenylene ethers (PPEs), excluding bisphenol A, can be modified to low-molecular-weight forms using specific bisphenol compounds with increased alkyl and aromatic ring content. In this case, unlike the redistribution reaction using bisphenol A, the modified PPEs exhibit no molecular rotation and have a high alkyl content. Consequently, the modified PPEs of the present invention exhibit excellent compatibility with other resins, improved flowability during laminate manufacturing, and low dielectric loss characteristics after crosslinking. Therefore, the moldability, processability, dielectric properties, heat resistance, and adhesive strength of printed circuit boards using the resin compositions of the present invention can be improved.

[0041] The above redistribution reaction is carried out in the presence of a free radical initiator, a catalyst, or both a free radical initiator and a catalyst.

[0042] The aforementioned bisphenol compounds with increased alkyl and aromatic content can be used without particular restriction as long as they are bisphenol compounds other than bisphenol A [BPA, 2,2-bis(4-hydroxyphenyl)propane]. Specifically, non-limiting examples of the aforementioned bisphenol compounds include bisphenol AP (1,1-bis(4-hydroxyphenyl)-1-phenylethane), bisphenol AF (2,2-bis(4-hydroxyphenyl)hexafluoropropane), bisphenol B (2,2-bis(4-hydroxyphenyl)butane), and bisphenol BP (2,2-bis(4-hydroxyphenyl)butane). Bis-(4-hydroxyphenyl)diphenylmethane, bisphenol C (2,2-bis(3-methyl-4-hydroxyphenyl)propane), bisphenol C (bis(4-hydroxyphenyl)-2,2-dichloroethylene), bisphenol G (2,2-bis(4-hydroxy-3-isopropylphenyl)propane), bisphenol C (bis(4-hydroxyphenyl)-2,2-dichloroethylene), bisphenol G (2,2-bis(4-hydroxy-3-isopropylphenyl)propane), bisphenol G (2,2-bis(4-hydroxy-3-isopropylphenyl)propane), bisphenol C (bis(4-hydroxyphenyl)-2,2-dichloroethylene), bisphenol G (2,2-bis(4-hydroxy-3-isopropylphenyl)propane), bisphenol G (2,2-bis(4-hydroxy-3-isopropylphenyl)propane), bisphenol C (bis(4-hydroxyphenyl)-2,2-dichloroethylene), bisphenol G (2,2-bis(4-hydroxy-3-isopropylphenyl)propane), bisphenol G (bis(4-hydroxy-3-isopropylphenyl)propane), bisphenol C (bis(4-hydroxyphenyl)-2,2-dichloroethylene), bisphenol G ...phenyl)-2,2-dichloroethylene), bisphenol G (bis(4-hydroxyphenyl)-2,2-dichloroethylene), bisphenol G (bis(4-hydroxyphenyl)-2,2-dichloroethylene), bisphenol G (bis(4-hydroxyphenyl)-2,2-dichloroethylene), bisphenol G (bis(4-hydroxyphenyl)-2,2-di 2-Bis(4-hydroxy-3-isopropyl-phenyl)propane), bisphenol M(1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene), bisphenol P(bis(4-hydroxyphenyl)sulfone), bisphenol PH(5,5'-(1-methylethylene)-bis[1,1'-(bisphenyl)-2-ol]propane(5,5'-(1-Meth) Bisphenol TMC (1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane), bisphenol Z (1,1-bis(4-hydroxyphenyl)-cyclohexane), etc., can be used alone or in combination of two or more.

[0043] The number-average molecular weight (Mn) of the aforementioned modified polyphenylene ether can be in the range of 1,000 to 10,000, specifically in the range of 1,000 to 5,000, and more specifically in the range of 1,000 to 3,000. This is obtained by modifying a high molecular weight polyphenylene ether resin with a number-average molecular weight in the range of 10,000 to 30,000 into a low molecular weight polyphenylene ether through a redistribution reaction in the presence of a bisphenol compound (excluding bisphenol A).

[0044] In addition, the molecular weight distribution (Mw / Mn) of the above-mentioned modified polyphenylene ether can be less than 3, specifically in the range of 1.5 to 2.5.

[0045] In the thermosetting resin composition of the present invention, the content of the modified polyphenylene ether can be about 10 to 50% by weight, specifically about 15 to 30% by weight, based on the total weight of the resin composition.

[0046] (b) Two or more curing agents

[0047] The thermosetting resin composition of the present invention contains two or more curing agents.

[0048] The aforementioned two or more curing agents, comprising two or more different curing agents, include (b1) hydrogenated polybutadiene and (b2) (hydrogenated) aromatic vinyl compound-conjugated diene copolymer. These two or more curing agents are cross-linking curing agents, enabling the modified polyphenylene ether to undergo three-dimensional cross-linking to form a resin matrix with a network structure. Therefore, since the aforementioned two or more curing agents cross-link the modified polyphenylene ether, the resin composition of the present invention, even containing modified polyphenylene ether with a lower molecular weight, can improve heat resistance and adhesion to other substrates (e.g., copper foil). Furthermore, since the aforementioned two or more curing agents must contain hydrogenated polybutadiene, the resin composition of the present invention exhibits low dielectric constant and low dielectric loss tangent, thus achieving low dielectric loss characteristics.

[0049] According to one example, in the two or more curing agents mentioned above, based on the total amount of the above resin composition, the content of (b1) hydrogenated polybutadiene and (b2) (hydrogenated) aromatic vinyl compound-conjugated diene copolymer can each be about 2 to 15% by weight. If the content of hydrogenated polybutadiene and (b2) (hydrogenated) aromatic vinyl compound-conjugated diene copolymer deviates from the above range, the glass transition temperature of the resin composition and its peel strength with metal foil (e.g., copper foil) may decrease.

[0050] In this invention, hydrogenated polybutadiene is a hydrogenated form of polybutadiene in which the vinyl group of polybutadiene is partially or completely hydrogenated. However, when the vinyl group of polybutadiene is completely (100%) hydrogenated, the modified polyphenylene ether exhibits low crosslinking degree and a lower glass transition temperature during resin composition curing, potentially resulting in reduced heat resistance. Therefore, this invention includes partially hydrogenated polybutadiene (“partially hydrogenated polybutadiene”).

[0051] For example, the hydrogenation rate of the aforementioned hydrogenated polybutadiene can be in the range of 80% to 99%. If the hydrogenation rate is less than 80%, the dielectric constant may increase during the curing of the resin composition due to the gradual oxidation of residual vinyl groups.

[0052] The hydrogenated polybutadiene that can be used in this invention can be a polybutadiene containing a first repeating unit represented by the following chemical formula 2.

[0053] [Chemical Formula 2]

[0054]

[0055] According to one example, the aforementioned hydrogenated polybutadiene may comprise a first repeating unit represented by chemical formula 2 and a second repeating unit represented by chemical formula 3.

[0056] [Chemical Formula 3]

[0057]

[0058] According to another example, the hydrogenated polybutadiene may include a first repeating unit represented by chemical formula 2, a second repeating unit represented by chemical formula 3, and a third repeating unit represented by chemical formula 4.

[0059] [Chemical Formula 4]

[0060]

[0061] The number-average molecular weight (Mn) of the aforementioned hydrogenated polybutadiene can be in the range of 500 to 3,000, preferably in the range of 1,000 to 3,000. If the number-average molecular weight of the hydrogenated polybutadiene is higher than 3,000, the moldability of the composition may be reduced.

[0062] In this invention, the (hydrogenated) aromatic vinyl compound-conjugated diene copolymer is an aromatic vinyl compound-conjugated diene copolymer, or a hydrogenated aromatic vinyl compound-conjugated diene copolymer as its hydrogenation, and is a copolymer or its hydrogenation composed of repeating unit A derived from an aromatic vinyl compound and repeating unit B derived from a conjugated diene compound. For example, there are aromatic vinyl compound-conjugated diene copolymers or their hydrogenations having structures such as AB, ABA, BAB, BABA, ABABA, etc., but it is not limited to these. In this case, the copolymer can be a random or block copolymer.

[0063] Aromatic vinyl compounds that can be used in this invention include styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene, etc., but are not limited thereto. One or more of these compounds may be used. For example, the aforementioned aromatic vinyl compounds may be styrene.

[0064] Conjugated diene compounds that can be used in this invention include butadiene (e.g., 1,3-butadiene), isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, etc., but are not limited thereto. One or more of these compounds may be used. For example, the aforementioned conjugated diene compound may be butadiene.

[0065] Specific examples of the aforementioned aromatic vinyl compound-conjugated diene copolymers include styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene-butene-styrene copolymer (SEBS), styrene-ethylene-propylene-styrene copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene copolymer (SEEPS), and styrene-ethylene-butene-ethylene copolymer (SEBC), but are not limited to these. Furthermore, specific examples of hydrogenated aromatic vinyl compound-conjugated diene copolymers are hydrides of the aforementioned aromatic vinyl compound-conjugated diene copolymers, specifically including partially hydrogenated styrene-butadiene-styrene copolymer (SBS), partially hydrogenated styrene-isoprene-styrene copolymer (SIS), partially hydrogenated styrene-ethylene-butene-styrene copolymer (SEBS), partially hydrogenated styrene-ethylene-propylene-styrene copolymer (SEPS), partially hydrogenated styrene-ethylene-ethylene-propylene-styrene copolymer (SEEPS), and partially hydrogenated styrene-ethylene-butene-ethylene copolymer (SEBC), etc.

[0066] The hydrogenation rate of the aforementioned hydrogenated aromatic vinyl compound-conjugated diene copolymer can be in the range of 60% to 85%. If the hydrogenation rate is below 60%, the improvement in dielectric properties may be minimal.

[0067] According to one example, the aforementioned hydrogenated aromatic vinyl compound-conjugated diene copolymer may contain a first repeating unit represented by chemical formula 2, a second repeating unit represented by chemical formula 3, and a fourth repeating unit represented by chemical formula 5.

[0068] [Chemical Formula 5]

[0069]

[0070] According to another example, the aforementioned hydrogenated aromatic vinyl compound-conjugated diene copolymer may contain a first repeating unit represented by chemical formula 2, a second repeating unit represented by chemical formula 3, a third repeating unit represented by chemical formula 4, and a fourth repeating unit represented by chemical formula 5.

[0071] On the other hand, the two or more curing agents mentioned above may further include curing agents that are different from the above-mentioned hydrogenated polybutadiene and (hydrogenated) aromatic vinyl compound-conjugated diene copolymers.

[0072] Examples of the aforementioned curing agents include crosslinking agents containing three or more (specifically three to four) functional groups, such as triallyl isocyanurate (TAIC) and 1,2,4-trivinylcyclohexane (TVCH); and others such as divinylnaphthalene, divinyl diphenyl, styrene monomer, phenol, triallyl cyanurate (TAC), and di-(4-vinylbenzyl)ether, but not limited to these. They can be used alone or in combination. For example, the aforementioned curing agents can be triallyl isocyanurate (TAIC), di-4-vinylbenzyl ether, or both.

[0073] Based on the total amount of the resin composition, the content of such curing agent can be about 1 to 25% by weight, specifically about 5 to 15% by weight.

[0074] In the thermosetting resin composition of the present invention, based on the total weight (100% by weight) of the resin composition, the content of the two or more curing agents can be about 5 to 25% by weight, specifically about 5 to 15% by weight. If the content of the two or more curing agents is less than 5% by weight or more than 25% by weight, the glass transition temperature and the peel strength with metal foil (e.g., copper foil) may decrease.

[0075] (c) Flame retardants

[0076] The thermosetting resin composition of the present invention contains a flame retardant.

[0077] The aforementioned flame retardants can be any commonly known flame retardants in the art, such as: halogenated flame retardants containing bromine or chlorine; phosphorus-based flame retardants such as trimethylol phosphate, triphenyl phosphate, tridichloropropyl phosphate, and phosphazene; antimony-based flame retardants such as antimony trioxide; and inorganic flame retardants such as metal hydroxides like aluminum hydroxide and magnesium hydroxide. In this invention, addition-type brominated flame retardants that are non-reactive with polyphenylene ether and do not reduce heat resistance and dielectric properties are suitable.

[0078] In this invention, the brominated flame retardant can be bromophthalimide, bromophenyl addition-type brominated flame retardant, or allyl-terminated tetrabromobisphenol A (tetrabromobisphenol A allyl ether) or divinylphenol flame retardant curing agent, thus simultaneously obtaining the properties of a curing agent and flame retardant properties. Alternatively, brominated organic compounds can also be used, such as decabromodiphenylethane, 4,4-dibromobiphenyl, and ethylenebistetrabromophthalimide.

[0079] In the thermosetting resin composition of the present invention, the content of the flame retardant, based on the total weight of the resin composition, can be in the range of about 5 to 30% by weight, specifically about 5 to 20% by weight, and more specifically about 7 to 10% by weight. If the content of the flame retardant is within the above range, it can sufficiently possess flame resistance at a flame retardant level of 94 V-0, and can exhibit excellent thermal resistance and electrical properties.

[0080] (d) Optionally, the above-mentioned thermosetting resin composition may further comprise selected from inorganic fillers, initiators, and... One or more of the group consisting of curing accelerators.

[0081] The thermosetting resin composition of the present invention may also contain inorganic fillers.

[0082] The aforementioned inorganic fillers can reduce the difference in coefficient of thermal expansion (CTE) between the (semi)cured resin composition and other layers (e.g., metal foil), thereby effectively improving the bending characteristics, low expansion, mechanical strength (toughness), and low stress of the final product.

[0083] The inorganic fillers that can be used in this invention are known in the art and are not particularly limited. For example, there are silica-based materials such as natural silica, fused silica, amorphous silica, and crystalline silica; boehmite, alumina, talc, spherical glass, calcium carbonate, magnesium carbonate, magnesium oxide, clay, calcium silicate, titanium dioxide, antimony oxide, glass fiber, aluminum borate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium dioxide, barium zirconate, calcium zirconate, boron nitride, silicon nitride, talc, and mica, which can be used alone or in combination. According to one example, the inorganic filler can be silica, specifically fused silica.

[0084] These inorganic fillers can be surface-treated with surface treatment agents. There are no particular limitations on the surface treatment agent, as long as it is generally known in the art; for example, silane coupling agents are used. In this case, based on 100 parts by weight of the inorganic filler, the content of the silane coupling agent can be approximately 0.1 to 20 parts by weight, specifically approximately 0.1 to 10 parts by weight.

[0085] The silane coupling agents used in this invention are not particularly limited to those commonly known in the art, such as vinyl-based, epoxy-based, methacryloxy-based, amino-based, mercapto / thioether-based, and acrylamide-based silane coupling agents, which can be used alone or in combination of two or more. These silane coupling agents can improve the adhesion between inorganic fillers and other components during the curing of thermosetting resin compositions.

[0086] As an example, the silane coupling agent can be a vinyl-based silane coupling agent (e.g., vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, etc.). In this case, it exhibits excellent compatibility with modified polyphenylene ethers containing unsaturated functional groups (e.g., vinyl and / or allyl) at both ends, thus further improving moisture absorption, heat resistance, and processability while reducing the dielectric constant and dielectric loss tangent.

[0087] There is no particular limitation on the content of such silane coupling agent. For example, based on 100 parts by weight of inorganic filler, it can be about 0.01 to 10 parts by weight, specifically about 0.1 to 5 parts by weight.

[0088] The aforementioned silane coupling agent can not only perform surface treatment on inorganic fillers, but can also be further added as a component of thermosetting resin compositions. In this case, the dispersibility of the inorganic filler can be improved by the silane coupling agent, thereby improving the dielectric properties of the cured resin composition (e.g., resin layer) or the prepreg using the resin composition.

[0089] Based on the total amount of the thermosetting resin composition, the content of such silane coupling agent can be from about 0.0001 to 10% by weight, specifically from about 0.01 to 5% by weight, and more specifically from about 0.1 to 3% by weight.

[0090] There are no particular limitations on the size of the inorganic fillers mentioned above, but a range of average particle size (D50) of about 0.5 to 2.5 μm is advantageous in terms of dispersibility.

[0091] Furthermore, there are no particular limitations on the content of the aforementioned inorganic fillers, and appropriate adjustments can be made considering factors such as bending characteristics and mechanical properties. For example, based on the total weight of the thermosetting resin composition, it can be in the range of approximately 20% to 60% by weight, specifically approximately 30% to 50% by weight. If the content of the aforementioned inorganic fillers is too high, the moldability may decrease.

[0092] On the other hand, the thermosetting resin composition of the present invention may also contain an initiator. An initiator is a substance that generates free radicals by means of heat, etc., which can further accelerate the curing of the modified polyphenylene ether or the curing agent and improve the heat resistance and other properties of the resin.

[0093] Non-limiting examples of initiators that can be used in this invention include α,α'-bis(tert-butylperoxide-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxide)-3-hexyne, benzoyl peroxide, 3,3',5,5′-tetramethyl-1,4-biphenylquinone, chloroquinone, 2,4,6-tritert-butylphenol, tert-butyl peroxide monocarbonate, azobisisobutylonitrile, etc. In addition, metal carboxylates may be further used.

[0094] Based on the total weight of the thermosetting resin composition, the content of the above initiator can be about 1 to 5% by weight, specifically about 0.1 to 2% by weight.

[0095] In addition, the thermosetting resin composition of the present invention may also contain a curing accelerator.

[0096] Examples of the aforementioned curing accelerators include organometallic salts or organometallic complexes containing one or more metals selected from the group consisting of iron, copper, zinc, cobalt, lead, nickel, manganese, and tin.

[0097] Specific examples of the aforementioned organometallic salts or organometallic complexes include iron naphthenate, copper naphthenate, zinc naphthenate, cobalt naphthenate, nickel naphthenate, manganese naphthenate, tin naphthenate, zinc octanoate, tin octanoate, iron octanoate, copper octanoate, zinc 2-ethylhexanoate, lead acetylacetonate, cobalt acetylacetonate, or dibutyltin maleate, but are not limited to these. Furthermore, they may be used individually or in combination.

[0098] The content of the above-mentioned curing accelerator may be in the range of about 0.01 to 1 part by weight relative to 100 parts by weight of modified polyphenylene ether, but is not limited thereto.

[0099] (e) Additives

[0100] In addition to the above-mentioned components, the thermosetting resin composition of the present invention may, as needed, further include various polymers such as thermosetting resins or thermoplastic resins and their oligomers (e.g., phenoxy resins, polyvinyl acetal resins, polyimides, polyamide-imides, polyethersulfones, polysulfones, etc.), solid rubber particles or ultraviolet absorbers, antioxidants, polymerization initiators, dyes, pigments, dispersants, thickeners, leveling agents, etc., without impairing the inherent properties of the above-mentioned resin composition.

[0101] For example, the additives mentioned above include: organic fillers such as silicone powder, nylon powder, and fluoropolymer powder; thickeners such as Orben and Bentone; polymeric defoamers or leveling agents such as silicone and fluoropolymers; binding agents such as imidazole, thiazole, triazole, and silane coupling agents (e.g., epoxy silanes, amino silanes, vinyl silanes); colorants such as phthalocyanine and carbon black; release agents such as higher fatty acids, higher fatty acid metal salts, and ester waxes; and stress relaxation agents such as modified silicone oils, silicone powders, and silicone resins. Additionally, it may contain additives commonly used in thermosetting resin compositions in the production of electronic devices (especially printed wiring substrates).

[0102] Based on the total amount of the above thermosetting resin composition, the content of these additives may be from about 0.001 to 10% by weight, specifically from about 0.01 to 5% by weight, and more specifically from about 0.01 to 1% by weight.

[0103] The thermosetting resin composition of the present invention described above can be in the form of a resin varnish containing an organic solvent. In this case, the resin composition can be dissolved or dispersed in an organic solvent.

[0104] The organic solvents that can be used in this invention can be any commonly known organic solvents in the art, such as acetone, cyclohexanone, methyl ethyl ketone, toluene, xylene, tetrahydrofuran, etc., which can be used alone or in combination of two or more.

[0105] The content of the aforementioned organic solvent can be within the range that satisfies the balance of 100 parts by weight of the varnish using the composition ratio of the aforementioned composition, and there is no particular limitation.

[0106] <Prepreg>

[0107] On the other hand, the present invention provides a prepreg comprising the above-described thermosetting resin composition.

[0108] The prepreg of the present invention is a fiber-reinforced composite material comprising a fiber-containing substrate and the above-mentioned thermosetting resin composition impregnated in the fiber-containing substrate.

[0109] The above-mentioned thermosetting resin composition can be a resin varnish in a form that is dissolved or dispersed in an organic solvent. Alternatively, the above-mentioned thermosetting resin composition can be a sheet that is cured to stage B (B-stage, semi-cured state) after being coated or impregnated onto a fibrous substrate and then heated.

[0110] The aforementioned fiber-containing substrate is a flexible fibrous assembly capable of being bent at will, serving as a support for metal foil laminates or printed circuit boards. Because it contains fibers, this fiber-containing substrate can reduce the dielectric constant and dielectric loss tangent of the metal foil laminate or printed circuit board, thereby improving low dielectric loss characteristics. Furthermore, during manufacturing, the fiber-containing substrate can be tightly bonded to the resin composition, exhibiting excellent flexibility, heat resistance, and adhesion.

[0111] The aforementioned fiber-containing substrate can be a substrate (component) composed of multiple fibers, or fibers such as yarn, woven fabric, non-woven fabric, knitting, braid, etc.

[0112] Non-limiting examples of the aforementioned fibers include: plant fibers such as cotton and linen; animal fibers such as wool and silk; regenerated fibers such as rayon; synthetic fibers such as polyester, acrylic, nylon, and polyurethane; inorganic fibers such as glass fiber and carbon fiber; and metal fibers. These can be used alone or in combination of two or more. Among these, inorganic fibers such as glass fiber and carbon fiber have low moisture content, thus preventing the formation of pores in the fiber-containing substrate during subsequent curing, and also exhibiting excellent thermal stability.

[0113] According to one example, the aforementioned fiber-containing substrate can be multiple glass fibers (e.g., E-glass, D-glass, S-glass, NE-glass, T-glass, and Q-glass), cellophane, glass roving, glass yarn, woven fabric, glass chopped strands, glass chopped strand mat, glass roving cloth, glass surfacing mat, etc., but is not limited to these.

[0114] The thickness of the fiber-containing substrate is not particularly limited; for example, it can be in the range of about 0.01 to 0.3 mm.

[0115] On the other hand, the surface of the aforementioned fiber-containing substrate can be treated with a silane coupling agent. In this case, the method of treatment with the silane coupling agent can be a conventional method known in the art. Since the description of the aforementioned silane coupling agent is the same as that in the description of the aforementioned resin composition, it is omitted here.

[0116] According to one example, the surface of the fiber-containing substrate can be treated with the same silane coupling agent used in inorganic fillers, specifically, with a vinyl silane coupling agent. In this case, not only is the adhesion between the fiber-containing substrate and the (semi)cured resin composition further improved, but the metal foil and prepreg in the metal foil laminate are also more firmly bonded, thus inhibiting foil peeling.

[0117] The prepreg of the present invention can be manufactured using methods known in the art, such as hot-melt methods and solvent methods. For example, the prepreg can be manufactured by coating or impregnating a resin composition onto a glass fabric and then heating and curing it to a semi-cured (stage B) state. In this case, the curing temperature can be in the range of about 70 to 170°C, and the curing time can be about 1 to 10 minutes. However, it is suitable to adjust the curing temperature and time according to the curing conditions of the resin composition.

[0118] The prepreg of the present invention described above can have a dielectric constant of about 3.0 to 3.5 and a dielectric loss coefficient of about 0.0020 to 0.0040 at about 10 GHz.

[0119] <Metal Foil Laminate>

[0120] The present invention provides a metal foil laminate comprising the above-described thermosetting resin composition.

[0121] According to one example, the metal foil laminate of the present invention comprises a metal foil and a resin layer disposed on one or both sides of the metal foil and composed of the thermosetting resin composition.

[0122] According to another example, the metal foil laminate of the present invention comprises a first metal foil, a resin layer disposed on one side of the first metal foil and composed of the aforementioned thermosetting resin composition, and a second metal foil disposed on the resin layer. In this case, the first metal foil and the second metal foil may be the same as or different from each other.

[0123] According to yet another example, the metal foil laminate of the present invention comprises a metal foil and a prepreg disposed on one or both sides of the metal foil and comprising the thermosetting resin composition described above. In this case, the prepreg may be a single layer or multiple layers.

[0124] According to yet another example, the metal foil laminate of the present invention comprises a first metal foil, a prepreg disposed on one side of the first metal foil and comprising the thermosetting resin composition, and a second metal foil disposed on the prepreg. In this case, the first metal foil and the second metal foil may be the same as or different from each other.

[0125] Here, the metal foil laminate can be a roll-to-roll metal foil laminate manufactured by rolling, or a sheet-like (non-roll-like) metal foil laminate cut to a certain size.

[0126] The aforementioned metal foil and the first and second metal foils can be made of metals or alloys known in the art without limitation. For example, they can be metal films or alloy films selected from the group consisting of copper (Cu), iron (Fe), nickel (Ni), titanium (Ti), aluminum (Al), silver (Ag), and gold (Au). For example, the metal foil and the first and second metal foils can be copper foil, which has excellent conductivity and is inexpensive. In this case, the copper foil can be made of copper foil known in the art without limitation, which can be manufactured by rolling and electrolysis, and can be treated with rust prevention to prevent surface oxidation and corrosion.

[0127] The surface roughness (Rz) of the matte side of the aforementioned metal foil and the first and second metal foils can, for example, be in the range of about 0.5 to 5 μm. In this case, the surface roughness (Rz) of the matte side of the first metal foil and the surface roughness (Rz) of the matte side of the second metal foil can be the same as or different from each other.

[0128] There are no particular limitations on the thickness of the aforementioned metal foil and the first and second metal foils; the thickness can be in the range of approximately 12 to 70 μm, taking into account the thickness or mechanical properties of the final product.

[0129] The aforementioned metal foil laminate can be manufactured using methods known in the art. For example, a copper foil laminate can be obtained by laminating a prepreg on one side of a first copper foil, then laminating a second copper foil on top of it, followed by heating and pressurization.

[0130] Printed Circuit Boards

[0131] On the other hand, the present invention provides a printed circuit board comprising the above-described thermosetting resin composition.

[0132] The printed circuit board of the present invention refers to a printed circuit board with one or more layers stacked by a plated through-hole method or a multilayer method, which can be obtained by stacking and aligning the above-mentioned prepreg or laminated sheets on the inner wiring board and then heating and pressing them into shape.

[0133] For example, the printed circuit board of the present invention includes the aforementioned metal foil laminate. In this case, the metal foils (first metal foil and / or second metal foil) included in the metal foil laminate can be formed with circuit patterns. Furthermore, the resin layer or prepreg included in the metal foil laminate serves as an insulating support member.

[0134] The aforementioned printed circuit board can be manufactured using conventional methods known in the art. For example, it can be manufactured as follows: while continuously feeding a roll of metal laminate using a roll-to-roll device, holes are made in the flexible metal laminate and through-hole plating is performed, and then the metal foil containing the plating (e.g., copper foil) is etched to form a circuit.

[0135] As explained above, the thermosetting resin composition exhibits low dielectric constant and dielectric loss tangent in the approximately 1 GHz to 100 GHz frequency band, and excellent heat resistance and processability. Therefore, printed circuit boards using the above-described thermosetting resin composition also exhibit low dielectric loss in the approximately 1 GHz to 100 GHz frequency band, reducing transmission losses in electrical, electronic, and communication devices, and also possess excellent heat resistance. Consequently, the printed circuit board of the present invention can be effectively used in various electrical, electronic, and communication devices such as mobile communication devices or their base station devices that process high-frequency to ultra-high-frequency signals, network-related electronic equipment such as servers and routers, mainframe computers, and automotive radar equipment.

[0136] The present invention will be specifically described below through embodiments, but the following embodiments and experimental examples are only illustrative of one way of the present invention, and the scope of the present invention is not limited to the following embodiments and experimental examples.

[0137] <Examples 1 ~ 8>

[0138] 1-1. Preparation of thermosetting resin compositions

[0139] A thermosetting resin composition is prepared by mixing modified polyphenylene ether (modified PPE), two or more curing agents, flame retardants, initiators, and fillers according to the composition described in Table 1 below. The content of each component in Table 1 below is in weight % and is based on the total amount (100 weight %) of the thermosetting resin composition.

[0140] 1-2. Manufacturing of copper foil laminates

[0141] The above-prepared thermosetting resin composition is impregnated with glass fiber (Asahi Kasei E glass Aminosilane) and dried at 165°C for 3 to 10 minutes to produce a prepreg. Then, the prepreg is laminated once on one side of a copper foil and pressed to produce a copper foil laminate with a thickness of 0.1 mm.

[0142] <Comparative Examples 1 ~ 6>

[0143] In addition to the composition described in Table 2 below, the thermosetting resin composition, prepreg, and copper foil laminate were manufactured using the same method as in the above embodiments. The content of each component in Table 2 below is in weight % and is based on 100% by weight of the thermosetting resin composition.

[0144] [Table 1]

[0145]

[0146] [Table 2]

[0147]

[0148] [Experimental Example 1] - Properties of Prepreg

[0149] The physical properties of the prepregs manufactured in Examples 1 to 8 and Comparative Examples 1 to 6 were tested as follows, and the results are shown in Tables 3 to 4 below.

[0150] 1) Dielectric constant (Dk) and dielectric loss tangent (Df)

[0151] According to the test standard of IEC 61189-2-721:2015, the evaluation substrates after removing the copper foil from the copper foil laminates manufactured in Examples 1 to 8 and Comparative Examples 1 to 6 were used, and the relative permittivity and dielectric loss tangent at a frequency of 10 GHz were measured using a relative permittivity measuring device (RF Impedence / Material Analyzer; Agilent).

[0152] 2) Resin flow (RF)

[0153] The resin flowability was determined using TECPOS from DAE JIN HYDRAULIC MACHINERY as follows. The semi-cured prepregs manufactured in Examples 1-8 and Comparative Examples 1-6 were stamped into four 4-inch × 4-inch sheets, and their weight (W1) was measured. Then, the prepregs were pressed at 50 bar for 1 minute on a hot plate at 150°C, and stamped into circles with half the weight of W1, and their weight (W2) was measured. The resin flowability (%) was calculated according to the following mathematical formula 1.

[0154] [Mathematical Expression 1]

[0155]

[0156] 3) Glass transition temperature (Tg) of TMA

[0157] The copper foil laminates manufactured in Examples 1-8 and Comparative Examples 1-6 were immersed in a copper etching solution to remove the copper foil, and then cut into 5 mm pieces to manufacture evaluation substrates. The glass transition temperature of the evaluation substrates was then determined using a TMA testing apparatus (TA Instrument, Q400).

[0158] [Table 3]

[0159]

[0160] [Table 4]

[0161]

[0162] The experimental results show that the thermosetting resin composition of the present invention not only has excellent low dielectric loss characteristics, but also excellent heat resistance and molding processability.

Claims

1. A thermosetting resin composition comprising: (a) A modified polyphenylene ether with an unsaturated substituent at at least one end of the molecular chain; (b) Two or more curing agents; and (c) Flame retardants, The two or more curing agents comprise (b1) hydrogenated polybutadiene and (b2) (hydrogenated) aromatic vinyl compound-conjugated diene copolymer.

2. The thermosetting resin composition according to claim 1, wherein the content of the hydrogenated polybutadiene and the (hydrogenated) aromatic vinyl compound-conjugated diene copolymer are each in the range of 2 to 15% by weight, based on the total amount of the resin composition.

3. The thermosetting resin composition according to claim 1, wherein the hydrogenated polybutadiene has a hydrogenation rate in the range of 80 to 99%.

4. The thermosetting resin composition according to claim 1, wherein the (hydrogenated) aromatic vinyl compound-conjugated diene copolymer has a hydrogenation rate in the range of 60% to 85%.

5. The thermosetting resin composition according to claim 1, wherein the two or more curing agents further comprise a curing agent.

6. The thermosetting resin composition according to claim 1, wherein, based on 100% by weight of the thermosetting resin composition, the content of the two or more curing agents ranges from 5% to 25% by weight.

7. The thermosetting resin composition according to claim 1, wherein the thermosetting resin composition further comprises one or more selected from the group consisting of initiators and fillers.

8. A prepreg comprising the thermosetting resin composition according to any one of claims 1 to 7.

9. A metal foil laminate comprising the thermosetting resin composition according to any one of claims 1 to 7.

10. A printed circuit board comprising the thermosetting resin composition according to any one of claims 1 to 7.

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