Resin composition, resin sheet, and circuit board material using the same

Abstract

To provide a resin composition that can give a sheet having low dielectric property and flame retardancy, and good appearance, a resin sheet and a circuit board material including the same.SOLUTION: A resin composition according to one embodiment of the present invention comprises a cyclic polyolefin resin copolymer with a crystal melting peak temperature of lower than 100°C, and a phosphorous ester compound, with a dielectric loss tangent of less than 0.005 at 10 GHz. A resin sheet according to another embodiment of the present invention comprises the resin composition. A circuit board material according to another embodiment of the present invention comprises a laminate structure of the resin sheet and a conductor.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition having low dielectric properties, excellent flame retardancy and sheet appearance, a resin sheet, and a circuit board material using the same. [Background technology]

[0002] Generally, the main circuit board materials used in electrical and electronic devices are copper-clad laminates (CCL), which are made by layering a resin-impregnated sheet (prepreg) on ​​a base material such as paper or glass, and then applying copper foil to the surface of the insulating plate obtained by heat and pressure treatment, or flexible printed circuit boards (FPC), which are made by forming an insulating adhesive layer on a base film and then laminating a conductive foil such as copper on top of that.

[0003] In recent years, communication frequencies have been increasing in order to improve the amount and speed of information transmission in electrical and electronic devices, and as a result, an increase in transmission loss (α) has become a major issue. The lower the value of this transmission loss (α), the less attenuation of the information signal, meaning that higher communication reliability can be ensured. Since transmission loss (α) is proportional to frequency (f), α increases in high-frequency communications, leading to reduced reliability. One method for reducing transmission loss (α) is to reduce the dielectric loss tangent (tanδ), which is proportional to α, just like frequency (f). For high-speed transmission of communication signals, materials with low dielectric loss tangent (tanδ), i.e., materials with low dielectric properties, are required.

[0004] As materials having low dielectric properties, for example, Patent Document 1 describes a low dielectric resin composition, a laminate, and a metal-clad laminate that contain a polyimide having a specific structure and a bisimide compound having a specific structure, and Patent Document 2 describes a cyclic olefin copolymer that has excellent dielectric properties, etc. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-006437 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-100843 Summary of the Invention [Problem to be solved by the invention]

[0006] The cyclic polyolefin resins exemplified in Patent Document 2 are known to exhibit particularly low dielectric properties because they do not have large polar groups, resulting in no imbalance in the charge distribution within the molecule and less susceptibility to moisture absorption. However, because cyclic polyolefin resins do not have oxygen atoms in their molecular structure, they are prone to generating highly flammable methane gas upon thermal decomposition, making them highly flammable. Therefore, when using cyclic polyolefin resins in electronic components such as flexible printed circuit boards (FPCs), improved flame retardancy is required to prevent fires.

[0007] One method for improving the flame retardancy is to add a flame retardant to the cyclic polyolefin resin. However, depending on the type of flame retardant, it may have poor compatibility with the cyclic polyolefin resin or may react with the cyclic polyolefin resin, resulting in foaming, discoloration, etc., and thus deteriorating the appearance of the sheet.

[0008] Therefore, an object of the present invention is to provide a resin composition which can give a sheet having low dielectric properties and flame retardancy and good appearance, a resin sheet, and a circuit board material using the same. [Means for solving the problem]

[0009] As a result of intensive research conducted by the present inventors to solve the above-mentioned problems, they found that by blending a phosphorus-based ester compound with a cyclic polyolefin resin copolymer, it is possible to prepare a resin composition that has flame retardancy while maintaining low dielectric properties, and further to obtain a sheet with good appearance, thereby solving the above-mentioned problems. That is, the present invention has the following features.

[0010] [1] A resin composition comprising a cyclic polyolefin resin copolymer having a crystalline melting peak temperature of less than 100°C and a phosphorus-based ester compound, and having a dielectric loss tangent of less than 0.005 at 10 GHz. [2] The resin composition according to [1] above, wherein the cyclic polyolefin resin copolymer is a resin having an alicyclic structure in a side chain of the polyolefin. [3] The resin composition according to [2] above, wherein the alicyclic structure is cyclohexane. [4] The resin composition according to any one of the above [1] to [3], wherein the cyclic polyolefin resin copolymer is a cyclic polyolefin containing at least one hydrogenated aromatic vinyl polymer block unit and at least one hydrogenated conjugated diene polymer block unit, or a modified product of the cyclic polyolefin with an unsaturated carboxylic acid and / or an anhydride thereof. [5] The resin composition according to [4] above, wherein the hydrogenated aromatic vinyl polymer block units have a hydrogenation level of 90% or more. [6] The resin composition according to [4] or [5] above, wherein the hydrogenated conjugated diene polymer block units have a hydrogenation level of 95% or more. [7] The resin composition according to any one of the above [1] to [6], wherein the phosphorus-based ester compound is at least one compound selected from the group consisting of phosphate esters, phosphonate esters, phosphinate esters, condensed phosphate esters, and phosphonitrile esters. [8] The resin composition according to any one of the above [1] to [7], wherein the phosphorus content in the phosphorus-based ester compound is 3% by mass or more and 40% by mass or less. [9] The resin composition according to any one of the above [1] to [8], which contains the phosphorus-based ester compound in an amount of 1% by mass or more and 30% by mass or less.

[10] The resin composition according to any one of [1] to [9] above, which has a flame retardancy of VTM-2 or higher in a vertical flame test UL94VTM of the safety standard UL94 in accordance with ASTM D4804.

[11] A resin sheet made of the resin composition according to any one of the above [1] to

[10] .

[12] A circuit board material obtained by laminating the resin sheet according to

[11] above and a conductor. [Effects of the Invention]

[0011] According to the present invention, it is possible to obtain a resin composition which can give a sheet having low dielectric properties and flame retardancy and having a good appearance, a resin sheet, and a circuit board material using the same. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described in detail below. However, the following description is an example of an embodiment of the present invention, and the present invention is not limited to the following description as long as it does not deviate from the gist of the present invention. In the following, when the expression "~" is used, it is used to include the numerical values ​​or physical property values ​​before and after it.

[0013] <<Resin composition>> The resin composition of the present invention contains a cyclic polyolefin resin copolymer having a crystalline melting peak temperature of less than 100°C and a phosphorus-based ester compound.

[0014] The dielectric loss tangent of the resin composition of the present invention is preferably less than 0.005 at 10 GHz, more preferably less than 0.004, and even more preferably less than 0.003. The smaller the dielectric loss tangent, the smaller the dielectric loss, and therefore the higher the transmission efficiency and speed of electrical signals when used as a circuit board material. The lower limit of the dielectric loss tangent is not particularly limited, and it is sufficient as long as it is 0 or more. The dielectric loss tangent in the present invention is a value measured at 23° C. and 10 GHz using a sheet having a thickness of 100 μm made from the resin composition.

[0015] The resin composition of the present invention preferably meets the VTM-2 or higher standard in the UL94VTM vertical flame test of the UL94 safety standard conforming to ASTM D4804, i.e., has flame retardancy of VTM-2 or higher, more preferably VTM-1 or higher, and even more preferably VTM-0. A resin composition that meets the VTM-2 or higher standard can prevent flames when used in electronic components. The flame retardancy of the resin composition of the present invention is evaluated based on the UL94 vertical flame test safety standard of Underwriters Laboratories, using a test sample prepared by cutting a 100 μm thick sheet from the resin composition into a length of 200 mm and a width of 50 mm.

[0016] <Cyclic polyolefin resin copolymer> The term "cyclic" in the cyclic polyolefin resin copolymer of the present invention refers to the alicyclic structure possessed by the cyclic polyolefin resin copolymer. Suitable examples of the alicyclic structure include cycloalkanes, bicycloalkanes, polycyclic compounds, etc., among which cycloalkanes are preferred, and cyclohexane is more preferred. The alicyclic structure is more preferably an alicyclic structure formed by hydrogenation of an aromatic ring contained in a hydrogenated aromatic vinyl polymer block unit described below.

[0017] (Physical properties of cyclic polyolefin resin copolymer) The cyclic polyolefin resin copolymer of the present invention has a crystalline melting peak temperature of less than 100°C. The crystalline melting peak temperature of the cyclic polyolefin resin copolymer is preferably 50° C. or higher, more preferably 60° C. or higher, and even more preferably 65° C. or higher. The crystalline melting peak temperature is preferably 90° C. or lower, and more preferably 85° C. or lower. The crystalline melting peak temperature in the present invention is the temperature at which a crystalline melting peak is detected in differential scanning calorimetry (DSC) measured at a heating rate of 10°C / min. The cyclic polyolefin resin copolymer of the present invention may have a crystalline melting peak at less than 100°C, and may have crystalline melting peaks at two points, for example, less than 100°C and at 100°C or higher.

[0018] Known cyclic polyolefins include hydrogenated ring-opening polymers having repeating units derived from monocyclic or polycyclic norbornene monomers (e.g., WO 2012 / 046443, WO 2012 / 033076, etc.). However, these cyclic polyolefins have an alicyclic structure in the main chain of the polymer, and either do not have a crystalline melting peak temperature below 100°C or are amorphous. On the other hand, the cyclic polyolefin resin copolymer of the present invention has a structure in which the polyolefin side chain has an alicyclic structure, and therefore has a crystalline melting peak temperature below 100°C.

[0019] The dielectric loss tangent of the cyclic polyolefin resin copolymer of the present invention is preferably less than 0.005 at 10 GHz, more preferably less than 0.001. The smaller the dielectric loss tangent, the smaller the dielectric loss, and therefore, when used as a circuit board material, the more efficient and faster the electrical signal transmission can be achieved. There is no particular lower limit for the dielectric loss tangent, and it is sufficient as long as it is 0 or more.

[0020] The melt flow rate (MFR) of the cyclic polyolefin resin copolymer of the present invention is not particularly limited, but is usually 0.1 g / 10 min or more, preferably 0.5 g / 10 min or more from the viewpoint of molding method and appearance of molded products, and is usually 200 g / 10 min or less, preferably 100 g / 10 min or less, more preferably 50 g / 10 min or less from the viewpoint of material strength. MFR is determined in accordance with ISO R1133 by measuring at a temperature of 230°C and a load of 2.16 kg.

[0021] <Cyclic polyolefin (a)> From the viewpoint of low dielectric properties, the cyclic polyolefin resin copolymer of the present invention is preferably a cyclic polyolefin containing at least one hydrogenated aromatic vinyl polymer block unit and at least one hydrogenated conjugated diene polymer block unit (hereinafter also referred to as "cyclic polyolefin (a)"), or a modified product of the cyclic polyolefin with an unsaturated carboxylic acid and / or an anhydride thereof (hereinafter also referred to as "modified cyclic olefin (a')").

[0022] As used herein, "block" refers to a polymeric segment of a copolymer that exhibits microphase separation from structurally or compositionally distinct polymeric segments of the copolymer. Microphase separation occurs due to immiscibility of the polymeric segments in the block copolymer. Microphase separation and block copolymers are extensively discussed in "Block Copolymers - Designer Soft Materials" in the February 1999 issue of PHYSICS TODAY, pp. 32-38.

[0023] Examples of the cyclic polyolefin (a) include a diblock copolymer consisting of a hydrogenated aromatic vinyl polymer block unit (hereinafter also referred to as "block A") and a hydrogenated conjugated diene polymer block (hereinafter also referred to as "block B"), a triblock copolymer containing two or more of at least one of block A and block B, a tetrablock copolymer, and a pentablock copolymer. The cyclic polyolefin (a) preferably contains at least two blocks A, and suitable examples thereof include the ABA type, ABAB type, and ABABA type.

[0024] Furthermore, the cyclic polyolefin (a) preferably contains a segment made of an aromatic vinyl polymer at each end. Therefore, the hydrogenated block copolymer of the present invention preferably has at least two hydrogenated aromatic vinyl polymer block units (blocks A) and at least one hydrogenated conjugated diene polymer block unit (block B) between the two hydrogenated aromatic vinyl polymer block units (blocks A). From these viewpoints, the cyclic polyolefin (a) is more preferably an ABA type or an ABABA type.

[0025] The content of the hydrogenated aromatic vinyl polymer block unit (block A) in the cyclic polyolefin (a) is preferably 30 to 99 mol %, more preferably 40 to 90 mol %, even more preferably 50 mol % or more, and even more preferably 60 mol % or more. If the ratio of the hydrogenated aromatic vinyl polymer block unit (block A) is equal to or greater than the lower limit, the rigidity will not decrease and the heat resistance and linear thermal expansion coefficient will be good. On the other hand, if the ratio is equal to or less than the upper limit, the flexibility will be good.

[0026] The content of the hydrogenated conjugated diene polymer block unit (block B) in the cyclic polyolefin (a) is preferably 1 to 70 mol %, more preferably 10 to 60 mol %, even more preferably 50 mol % or less, and even more preferably 40 mol % or less. If the ratio of the hydrogenated conjugated diene polymer block unit (block B) is equal to or greater than the lower limit, flexibility is improved. On the other hand, if the ratio is equal to or less than the upper limit, rigidity is not reduced and heat resistance and linear thermal expansion coefficient are improved.

[0027] The hydrogenated aromatic vinyl polymer block unit and the hydrogenated conjugated diene polymer block unit constituting the cyclic polyolefin (a) can be obtained by hydrogenating polymer blocks composed of an aromatic vinyl monomer and a conjugated diene monomer such as 1,3-butadiene, which will be described in detail later. Furthermore, the cyclic polyolefin (a) is preferably a block copolymer having no functional groups. The term "no functional groups" means that the block copolymer does not contain any functional groups, i.e., groups containing atoms other than carbon and hydrogen atoms.

[0028] The monomers for forming the aromatic vinyl polymer block unit and the conjugated diene polymer block unit before hydrogenation will be described below.

[0029] (aromatic vinyl monomer) The aromatic vinyl monomer serving as a raw material for the aromatic vinyl polymer block unit before hydrogenation is a monomer represented by the general formula (1).

[0030] [ka]

[0031] In the above general formula (1), R is hydrogen or an alkyl group, and Ar is a phenyl group, a halophenyl group, an alkylphenyl group, an alkylhalophenyl group, a naphthyl group, a pyridinyl group, or an anthracenyl group.

[0032] When R is an alkyl group, the number of carbon atoms is preferably 1 to 6, and the alkyl group may be mono- or polysubstituted with functional groups such as halo groups, nitro groups, amino groups, hydroxy groups, cyano groups, carbonyl groups, and carboxyl groups. Furthermore, the Ar is preferably a phenyl group or an alkylphenyl group, and more preferably a phenyl group.

[0033] Examples of aromatic vinyl monomers include styrene, α-methylstyrene, vinyltoluene (including all isomers, with p-vinyltoluene being particularly preferred), ethylstyrene, propylstyrene, butylstyrene, vinylbiphenyl, vinylnaphthalene, vinylanthracene (including all isomers), and mixtures thereof, with styrene being particularly preferred.

[0034] (Conjugated diene monomer) The conjugated diene monomer that is the raw material for the conjugated diene polymer block unit before hydrogenation is not particularly limited as long as it is a monomer having two conjugated double bonds. Examples of conjugated diene monomers include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2-methyl-1,3-pentadiene and analogous compounds thereof, and mixtures thereof. Of these, 1,3-butadiene is preferred.

[0035] When 1,3-butadiene is used as the conjugated diene monomer, its polymer, polybutadiene, contains 1,4-bond units ([-CH-CH=CH-CH-]) and 1,2-bond units ([-CH-CH(CH=CH)-]). Upon hydrogenation, the former gives a structure similar to the repeating unit of polyethylene (ethylene structure), and the latter gives a structure similar to the repeating unit obtained by polymerizing 1-butene (1-butene structure). Therefore, the hydrogenated conjugated diene polymer block according to the present invention preferably contains at least one of an ethylene structure and a 1-butene structure. Furthermore, when isoprene is used as the conjugated diene monomer, its polymer, polyisoprene, contains 1,4-bond units ([-CH2-C(CH3)=CH-CH2-]), 3,4-bond units ([-CH2-CH(C(CH3)=CH2)-]), and 1,2-bond units ([-CH2-C(CH3)(CH=CH2)-]), and contains at least one of the three types of repeating units obtained by hydrogenation.

[0036] (Block structure) The cyclic polyolefin (a) is preferably produced by hydrogenation of a triblock copolymer or a multiblock copolymer such as SBS, SBSB, SBSBS, SBSBSB, SIS, SISIS, and SISBS (where S is polystyrene, B is polybutadiene, and I is polyisoprene). The block may be a linear block or a branched block. When branched, the polymerization chain may be bonded at any position along the backbone of the copolymer. In addition to a linear block, the block may be a tapered block or a star block.

[0037] The block copolymer constituting the cyclic polyolefin (a) before hydrogenation may contain one or more additional block units other than the aromatic vinyl polymer block units and the conjugated diene polymer block units. For example, in the case of a triblock copolymer, these additional block units may be bonded to any position on the triblock polymer skeleton.

[0038] A preferred example of the hydrogenated aromatic vinyl polymer block unit is hydrogenated polystyrene, and a preferred example of the hydrogenated conjugated diene polymer block unit is hydrogenated polybutadiene or hydrogenated polyisoprene, with hydrogenated polybutadiene being more preferred. A preferred embodiment of the cyclic polyolefin (a) is a hydrogenated triblock or pentablock copolymer of styrene and butadiene, and it is preferred that the cyclic polyolefin (a) does not contain any other functional group or structural modifier.

[0039] (hydrogenation level) The cyclic polyolefin (a) is a polyolefin in which the double bonds derived from conjugated dienes such as butadiene as well as the aromatic rings derived from styrene and the like are hydrogenated, and the polyolefin is substantially completely hydrogenated. Specifically, the cyclic polyolefin (a) is a polyolefin having the following hydrogenation levels: The hydrogenation level of the hydrogenated aromatic vinyl polymer block unit is preferably 90% or more, more preferably 95% or more, even more preferably 98% or more, and particularly preferably 99.5% or more. The hydrogenation level of the hydrogenated conjugated diene polymer block units is preferably 95% or more, more preferably 99% or more, and even more preferably 99.5% or more. Such a high level of hydrogenation reduces dielectric loss and also improves stiffness and heat resistance. The hydrogenation level of the hydrogenated aromatic vinyl polymer block unit refers to the proportion of the aromatic vinyl polymer block unit saturated by hydrogenation, and the hydrogenation level of the hydrogenated conjugated diene polymer block unit refers to the proportion of the conjugated diene polymer block unit saturated by hydrogenation. The hydrogenation level of each block unit is determined using proton NMR.

[0040] The cyclic polyolefin (a) may be used alone or in combination of two or more kinds. As the cyclic polyolefin (a) of the present invention, commercially available products can be used, and a specific example thereof is Tefablock (registered trademark) manufactured by Mitsubishi Chemical Corporation.

[0041] <Modified cyclic polyolefin (a')> The cyclic polyolefin resin copolymer of the present invention may be a modified cyclic polyolefin (a'). The modified cyclic polyolefin is a product of the above-mentioned cyclic polyolefin (a) modified with an unsaturated carboxylic acid and / or anhydride thereof. By modifying the cyclic polyolefin (a), the polarity of the polymer increases, which is expected to improve adhesion to metal layers such as copper foil.

[0042] (Modification of cyclic polyolefin (a)) The modification procedure of the cyclic polyolefin (a) is described below. This modification procedure is preferably carried out by adding an unsaturated carboxylic acid and / or anhydride thereof as a modifier to the cyclic polyolefin (a) and allowing it to react.

[0043] [Denaturant] Examples of the unsaturated carboxylic acid and / or anhydride thereof as the modifying agent include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, and nadic acids, and their anhydrides. Specific examples of the acid anhydride include maleic anhydride, citraconic anhydride, and nadic anhydrides. Examples of nadic acids or anhydrides thereof include endo-cis-bicyclo[2.2.1]hept-2,3-dicarboxylic acid (nadic acid), methyl-endo-cis-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid (methylnadic acid), and the like, and anhydrides thereof.

[0044] Among these unsaturated carboxylic acids and / or anhydrides thereof, acrylic acid, maleic acid, nadic acid, maleic anhydride, and nadic anhydride are preferred. The unsaturated carboxylic acid and / or anhydride thereof may be used alone or in combination of two or more kinds.

[0045] [Denaturation method] As a method for modifying the cyclic polyolefin (a), solution modification, melt modification, solid phase modification by irradiation with electron beams or ionizing radiation, modification in a supercritical fluid, etc. are preferably used. Among these, melt modification is preferred because of its superior equipment and cost competitiveness, and melt kneading modification using an extruder is more preferred because of its superior continuous productivity. Examples of the apparatus that can be used here include a single-screw extruder, a twin-screw extruder, a Banbury mixer, and a roll mixer. Among these, a single-screw extruder and a twin-screw extruder are preferred because of their excellent continuous productivity.

[0046] In general, modification of cyclic polyolefin (a) with an unsaturated carboxylic acid and / or its anhydride is carried out by a grafting reaction in which a carbon-hydrogen bond of a hydrogenated conjugated diene polymer block unit, which is one of the block units constituting the cyclic polyolefin (a), is cleaved to generate a carbon radical, to which an unsaturated functional group is added. As a source of carbon radicals, in addition to the above-mentioned electron beams and ionizing radiation, a method using high temperature or a radical generator such as an organic peroxide, an inorganic peroxide, an azo compound, etc. is also usable. As the radical generator, it is preferable to use an organic peroxide from the viewpoint of cost and operability.

[0047] Examples of the azo compound include azobisisobutyronitrile, azobisdimethylvaleronitrile, azobis(2-methylbutyronitrile), and diazonitrophenol. Examples of the inorganic peroxides include hydrogen peroxide, potassium peroxide, sodium peroxide, calcium peroxide, magnesium peroxide, and barium peroxide.

[0048] The organic peroxides include those belonging to the groups of hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxyesters, and ketone peroxides. Specific examples include hydroperoxides such as cumene hydroperoxide and t-butyl hydroperoxide; dialkyl peroxides such as dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3; diacyl peroxides such as lauryl peroxide and benzoyl peroxide; peroxy esters such as t-butyl peroxyacetate, t-butyl peroxybenzoate and t-butylperoxyisopropyl carbonate; and ketone peroxides such as cyclohexanone peroxide. These radical generators may be used alone or in combination of two or more.

[0049] [Melt kneading modification] A commonly used melt-kneading modification procedure involves blending a cyclic polyolefin (a), an unsaturated carboxylic acid and / or its anhydride, and an organic peroxide, feeding the mixture into a kneader and extruder, extruding the mixture while heating, melting, and kneading it, and cooling the molten resin emerging from the tip of a die in a water tank or the like to obtain a modified cyclic polyolefin (a').

[0050] The blending ratio of the cyclic polyolefin (a) and the unsaturated carboxylic acid and / or its anhydride is preferably 0.2 to 5 parts by mass of the unsaturated carboxylic acid and / or its anhydride per 100 parts by mass of the cyclic polyolefin (a). When the blending ratio of the unsaturated carboxylic acid and / or its anhydride to the cyclic polyolefin (a) is equal to or greater than the lower limit, a predetermined modification rate necessary for achieving the effects of the present invention can be obtained. On the other hand, when the blending ratio is equal to or less than the upper limit, no unreacted unsaturated carboxylic acid and / or its anhydride remain, which is preferable in terms of dielectric properties.

[0051] The blending ratio of the unsaturated carboxylic acid and / or its anhydride to the organic peroxide is preferably 20 to 100 parts by mass of the organic peroxide per 100 parts by mass of the unsaturated carboxylic acid and / or its anhydride. When the blending ratio of the organic peroxide to the unsaturated carboxylic acid and / or its anhydride is equal to or greater than the lower limit, a predetermined modification rate necessary for achieving the effects of the present invention can be obtained. When the blending ratio is equal to or less than the upper limit, the cyclic polyolefin (a) does not deteriorate, and the color does not deteriorate.

[0052] As for the melt-kneading modification conditions, for example, it is preferable to extrude at a temperature of 150 to 300°C in a single-screw extruder or a twin-screw extruder.

[0053] [Degeneration rate] The degree of modification of the modified cyclic polyolefin (a') with the unsaturated carboxylic acid and / or anhydride thereof is preferably 0.1 to 2% by mass. A modification rate of at least the lower limit is preferable because the polarity of the polymer increases and the adhesion to a metal layer such as a copper foil improves. A modification rate of at most the upper limit can prevent the dielectric loss of the cyclic polyolefin (a) from increasing. Furthermore, odor generation and color deterioration can be prevented. The modification rate of the modified cyclic polyolefin (a') can be measured by proton NMR after the modified cyclic polyolefin (a') is subjected to a methyl esterification treatment.

[0054] <Phosphorus ester compound (b)> The resin composition of the present invention contains a phosphorus-based ester compound (b) as a flame retardant. Generally, known flame retardants include halogen-based, phosphorus-based, vinyl group-containing, epoxy group-containing, hydroxyl group-containing, etc. Among these, phosphorus-based flame retardants have a small environmental impact and relatively little effect on dielectric properties, and therefore tend to be able to achieve both low dielectric properties and flame retardancy. Known phosphorus-based flame retardants include red phosphorus, phosphorus-based ester compounds, phosphates, phosphorus halides, etc. In the present invention, it has been found that by using a phosphorus-based ester compound among these, compatibility with the cyclic polyolefin resin copolymer is improved, and a resin sheet with good appearance that is free from foaming and yellowing can be produced.

[0055] (Structure of phosphorus ester compound (b)) The phosphorus-based ester compound (b) in the present invention preferably does not contain a halogen element from the viewpoint of reducing the environmental load, and may be a composite system of phosphorus and nitrogen from the viewpoint of efficiently improving flame retardancy. Specifically, at least one compound selected from the group consisting of phosphate esters, phosphonate esters, phosphinate esters, condensed phosphate esters, and phosphonitrile esters is preferred, and among these, from the viewpoint of flame retardancy, at least one compound selected from the group consisting of phosphonate esters, condensed phosphate esters, and phosphonitrile esters is more preferred. The compounds exemplified above preferably have an aromatic group from the viewpoint of compatibility with the cyclic polyolefin resin copolymer.

[0056] As the phosphorus-based ester compound (b), various known compounds can be used, and commercially available phosphorus-based ester compounds include those available from Teijin Limited under the trade name "Fireguard (registered trademark) FCX-210," Daihachi Chemical Industry Co., Ltd. under the trade names "CR-741" and "PX-200," and Fushimi Pharmaceutical Co., Ltd. under the trade names "Lavitol (registered trademark) FP-100" and "Lavitol (registered trademark) FP-110."

[0057] (Phosphorus content of phosphorus ester compound (b)) The phosphorus content of the phosphorus-based ester compound (b) of the present invention is preferably 3% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 30% by mass or less, and even more preferably 7% by mass or more and 25% by mass or less. When the phosphorus content is equal to or greater than the above lower limit, the flame retardancy of the resin composition can be effectively improved, and when the phosphorus content is equal to or less than the above upper limit, the low dielectric properties of the resin composition can be maintained. The phosphorus content can be measured, for example, by atomic absorption spectrometry.

[0058] (Content of phosphorus ester compound (b)) The content of the phosphorus-based ester compound (b) in the resin composition of the present invention is preferably 1% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 20% by mass or less, and even more preferably 3% by mass or more and 15% by mass or less, based on the total mass of the resin composition of the present invention. When the content of the phosphorus-based ester compound (b) is equal to or greater than the above lower limit, the flame retardancy of the resin composition can be effectively improved, and when the content is equal to or less than the above upper limit, the low dielectric properties and elastic modulus of the resin composition can be maintained.

[0059] <Other ingredients> The resin composition of the present invention may optionally contain components other than the cyclic polyolefin resin copolymer and the phosphorus-based ester compound, such as a thermoplastic elastomer other than the cyclic polyolefin resin copolymer, an ultraviolet protection agent, an antistatic agent, an antioxidant, a coupling agent, a plasticizer, an inorganic flame retardant, an anti-drip agent, a colorant, a dispersant, an emulsifier, an elasticity reducing agent, a diluent, an antifoaming agent, an ion trapping agent, an inorganic filler, and an organic filler.

[0060] <Method of manufacturing resin composition> The resin composition of the present invention can be produced by mixing a cyclic polyolefin resin copolymer and a phosphorus-based ester compound. For example, the resin composition may be produced by melt-kneading the cyclic polyolefin resin copolymer and the phosphorus-based ester compound using a kneader or a stirrer. Alternatively, the resin composition may be produced by dissolving the cyclic polyolefin resin in a solvent, adding and mixing the phosphorus-based ester compound, and then removing the solvent by evaporation or the like. Among these, the melt-kneading method is preferred from the viewpoint of ease of molding.

[0061] <<Resin sheet>> The resin sheet of the present invention can be obtained by forming the above-mentioned resin composition into a sheet. The method for producing the resin sheet is not particularly limited, but known methods such as extrusion molding, injection molding, blow molding, vacuum molding, pressure molding, and press molding can be used. When the resin sheet of the present invention is produced by kneading using an extruder or the like, it is preferable to melt-knead the resin composition in a heated state, usually at 180 to 300°C, preferably 220 to 280°C.

[0062] The thickness of the resin sheet in the present invention is preferably 10 μm to 500 μm, more preferably 20 μm to 300 μm, and even more preferably 50 μm to 200 μm. By keeping the thickness within the above range, it is possible to obtain a circuit board material that can accommodate the miniaturization of electric and electronic devices while maintaining appropriate strength.

[0063] <<Applications of resin compositions>> Examples of applications of the resin composition of the present invention include, but are not limited to, circuit board materials including circuit board materials for electric and electronic devices such as copper foil laminates, flexible printed circuit boards, multilayer printed wiring boards, and capacitors, underfill materials, interchip fills for 3D-LSIs, insulating sheets, and heat dissipation substrates.

[0064] <Circuit board materials> The resin sheet of the present invention can be used as a circuit board material by laminating it with a conductor.

[0065] The conductor may be a metal foil made of a conductive metal such as copper or aluminum, or an alloy containing such a metal, or a metal layer formed by plating or sputtering.

[0066] When used as a circuit board material for electric and electronic devices, the resin sheet preferably has a thickness of 10 μm or more and 200 μm or less, and the conductor preferably has a thickness of 0.2 μm or more and 70 μm or less.

[0067] The circuit board material of the present invention is characterized by a sufficiently low dielectric loss tangent. The dielectric loss tangent of the circuit board material is preferably less than 0.01 at 10 GHz, and more preferably less than 0.008. The lower the dielectric loss tangent, the more efficient and faster the electrical signal transmission will be when used in a circuit board. There is no particular lower limit to the dielectric loss tangent, and it is sufficient as long as it is 0 or greater.

[0068] <Method of manufacturing circuit board materials> The circuit board material of the present invention can be produced, for example, by the following method. After laminating a conductor on the resin sheet of the present invention, a circuit is formed using a photoresist or the like, and the required number of such layers are laminated. The lamination of the resin sheet and the conductor may be performed by directly laminating a conductive metal foil on the resin composite, by bonding the resin composite and the conductive metal foil with an adhesive, by forming a conductive metal layer by plating or sputtering, or by combining these methods. [Example]

[0069] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following examples and comparative examples, various physical properties were measured by the following methods.

[0070] <Measurement method> (1) Dielectric properties The dielectric loss tangent in the in-plane direction of the resin sheet was measured at 23° C. using a cavity resonator method, and evaluated according to the following criteria. The measurement frequency was 10 GHz. [Evaluation criteria] A (good): Dielectric tangent less than 0.005 B (poor): Dielectric tangent is 0.005 or more

[0071] (2) Flame retardancy The flame retardancy of the resin sheet was evaluated based on the procedure of the UL94 vertical flame test, a safety standard from Underwriters Laboratories. The flame test was conducted on five resin sheets using test pieces measuring 200 mm in length, 50 mm in width, and 0.1 mm in thickness. The evaluation was based on the following criteria, which are based on the UL94 vertical flame test (UL94VTM) criteria. [Evaluation criteria] A (good): Passed either VTM-0, VTM-1, or VTM-2 B (poor): Failed VTM-2

[0072] (3) Film formability The appearance of the resin sheet after extrusion molding was observed, and those in which no foaming or yellowing was observed were rated as ◯ (good), and those in which foaming or yellowing was observed were rated as × (bad).

[0073] <Raw materials> [Cyclic polyolefin resin copolymer] As the modified cyclic polyolefin (a'-1), "TEFABLOC (registered trademark) CP CP401" manufactured by Mitsubishi Chemical Corporation was used. Crystal melting peak temperature: 75℃ Dissipation factor: 0.0008 (10GHz) ·Density (ASTM D792): 0.94g / cm 3 ·MFR (230℃, 2.16kg): 3g / 10 minutes Hydrogenated aromatic vinyl polymer block unit: Hydrogenated polystyrene with a content of 67 mol% and a hydrogenation level of 99.5% or more Hydrogenated conjugated diene polymer block units: Hydrogenated polybutadiene with a content of 33 mol% and a hydrogenation level of 99.5% or higher Block structure: Pentablock structure, Total hydrogenation level: 99.5% or more Maleic acid modification rate: 1.2% by mass Mw:68000

[0074] [Phosphorus ester compound (b)] b-1: "Lavitor (registered trademark) FP-100" manufactured by Fushimi Pharmaceutical Co., Ltd. (aromatic group-containing phosphonitrile acid ester, phosphorus content: 13% by mass / nitrogen content: 6% by mass) b-2: "PX-200" manufactured by Daihachi Chemical Industry Co., Ltd. (aromatic condensed phosphate ester, phosphorus content: 9% by mass) b-3: Teijin Limited's "Fireguard (registered trademark) FCX-210" (aromatic group-containing phosphonic acid ester, phosphorus content: 15% by mass)

[0075] [Other phosphorus-based flame retardants] b-4: Clariant Chemicals Co., Ltd. "EXOLIT AP422" (ammonium polyphosphate, phosphorus content: 31% by mass / nitrogen content: 15% by mass)

[0076] Example 1 The modified cyclic polyolefin (a'-1) and the phosphorus-based ester compound (b-1) were melt-kneaded using a coaxial twin-screw extruder to form a resin composition, which was then extruded through a T-die and cooled and solidified using a casting roll to form a 100 μm-thick resin sheet. The dielectric properties and flame retardancy of the resulting resin sheet were evaluated. The results are shown in Table 1.

[0077] <Examples 2 to 5, Comparative Examples 1 and 2> A resin sheet was produced in the same manner as in Example 1, except that the modified cyclic polyolefin (a'-1) and the phosphorus-based ester compound were melt-kneaded in the formulation shown in Table 1. The dielectric properties and flame retardancy of the obtained resin sheet were evaluated. The results are shown in Table 1.

[0078] [Table 1]

[0079] The results of Examples 1 to 5 in Table 1 above show that by blending a phosphorus-based ester compound with a cyclic polyolefin resin copolymer, it is possible to impart flame retardancy of VTM-2 or higher while maintaining a low dielectric tangent. Furthermore, the resin sheets of Examples 1 to 5 were free from foaming or yellowing and had good appearances. The resin composition of the present invention is expected to have a flame retardant effect, and therefore can be expected to be used in electronic components such as materials for flexible printed circuit boards (FPCs).

[0080] On the other hand, Comparative Example 1, which did not contain a phosphorus-based ester compound, failed VTM-2, indicating that the cyclic polyolefin resin copolymer alone was inferior in flame retardancy. Furthermore, Comparative Example 2 suggests that when a phosphorus-based flame retardant that is not an ester compound is used, foaming and coloring are observed during extrusion film formation, resulting in poor appearance.

Claims

1. A resin composition containing a cyclic polyolefin resin copolymer having a crystalline melting peak temperature of less than 100°C and a phosphorus-based ester compound, the resin composition having a dielectric loss tangent of less than 0.005 at 10 GHz, The cyclic polyolefin resin copolymer is a resin having an alicyclic structure in a side chain of a polyolefin, the cyclic polyolefin resin copolymer is a cyclic polyolefin containing at least one hydrogenated aromatic vinyl polymer block unit and at least one hydrogenated conjugated diene polymer block unit modified with an unsaturated carboxylic acid and / or an anhydride thereof, the cyclic polyolefin resin copolymer contains segments made of an aromatic vinyl polymer at each end, the content of the hydrogenated aromatic vinyl polymer block unit in the cyclic polyolefin resin copolymer is 30 to 99 mol %; the content of the hydrogenated conjugated diene polymer block unit in the cyclic polyolefin resin copolymer is 1 to 70 mol %, the hydrogenation level of the hydrogenated aromatic vinyl polymer block unit in the cyclic polyolefin resin copolymer is 90% or more; the hydrogenated conjugated diene polymer block unit in the cyclic polyolefin resin copolymer has a hydrogenation level of 95% or more; the modification rate of the cyclic polyolefin resin copolymer is 0.1 to 2 mass %, A resin composition in which the content of the phosphorus-based ester compound is 5% by mass or more and 30% by mass or less based on the entire resin composition.

2. The resin composition according to claim 1 , wherein the alicyclic structure is cyclohexane.

3. 3. The resin composition according to claim 1, wherein the phosphorus-based ester compound is at least one compound selected from the group consisting of phosphate esters, phosphonate esters, phosphinate esters, condensed phosphate esters, and phosphonitrile esters.

4. The resin composition according to any one of claims 1 to 3, wherein the phosphorus content in the phosphorus-based ester compound is 3% by mass or more and 40% by mass or less.

5. The resin composition according to any one of claims 1 to 4, wherein the phosphorus-based ester compound is a composite of phosphorus and nitrogen.

6. The resin composition according to any one of claims 1 to 5, which has a flame retardancy of VTM-2 or higher in a vertical flame test UL94VTM of safety standard UL94 in accordance with ASTM D4804.

7. A resin sheet comprising the resin composition according to any one of claims 1 to 6.

8. A circuit board material obtained by laminating the resin sheet according to claim 7 and a conductor.

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