Compounds, curable compositions, and cured films

Abstract

To provide a compound capable of forming a cured product characterized by low values of dielectric constant and dielectric loss, with superior heat resistance and excellent adhesion to metals.SOLUTION: The present invention provides a compound represented by the formula (1) [where at least two or more of R1-R15 comprise an ethylenically unsaturated bond].SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to compounds, curable compositions, and cured films. [Background technology]

[0002] As communication systems become more sophisticated and faster, there is a growing demand for technologies that can effectively utilize higher frequency electromagnetic waves. Specifically, to suppress delays and losses in electrical signal transmission, insulating materials used to form circuit boards and antenna wiring must possess electrical properties such as low dielectric constant and low dielectric loss tangent. Suitable insulating materials with such electrical properties include those with molecular structures that exhibit smaller electronic polarization.

[0003] Furthermore, in order to eliminate harmful effects on the human body and adverse effects on the natural environment, there is a growing trend to replace lead-free solder with lead-free solder used to form wiring. However, because lead-free solder has a high melting point, the materials used to form circuits require higher heat resistance (thermal deformation resistance, glass transition temperature) than before. For this reason, such materials are required to have high rigidity and a molecular structure with few degrees of freedom.

[0004] A common process for forming an insulating layer in a circuit involves crosslinking and curing a curable composition containing an oligomer having crosslinkable sites and a crosslinking agent by heating or light irradiation during circuit formation. However, with existing curable compositions containing epoxy crosslinking agents, crosslinking occurs via highly polarized ether bonds, and hydroxyl groups are generated upon ring-opening of the epoxy groups, resulting in cured products (insulating layers) that cannot satisfy the aforementioned electrical properties. On the other hand, with existing curable compositions containing olefin-based crosslinking agents, which yield good electrical properties, it was not possible to obtain cured products (insulating layers) with a sufficient glass transition temperature. Furthermore, for example, Patent Document 1 describes that curable compositions containing styrene compounds can yield good electrical properties.

[0005] Furthermore, a decrease in polarization within the molecule can lead to a deterioration in adhesion to metals such as copper. Therefore, the cured product (insulating layer) is required to maintain the same level of adhesion as conventional materials. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2004-83680 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, since no existing material simultaneously satisfied the aforementioned electrical properties, heat resistance, and adhesive properties, there was a need for compounds based on new molecular designs.

[0008] The present invention has been made in view of the above, and aims to provide a compound that can form a cured product having a low dielectric constant and dielectric loss tangent, and excellent heat resistance and adhesion to metals, etc. [Means for solving the problem]

[0009] The inventors diligently studied to solve the aforementioned problems. As a result, they found that the aforementioned problems can be solved according to the following configuration example, and thus completed the present invention. The configuration example of the present invention is as follows.

[0010] [1] A compound represented by the following formula (1).

[0011] [ka] [In formula (1), R 1 ~R 15 Each of these is independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and at least two of these have ethylenically unsaturated bonds. 1 ~R 15two or more of them may be bonded to each other to form a ring.]

[0012] [2] The compound according to [1], which is a compound represented by the following formula (2).

[0013]

Chemical Formula

[0014] [3] A curable composition comprising the compound according to [1] or [2]. [4] A cured film obtained from the curable composition according to [3].

Effects of the Invention

[0015] According to the present invention, a cured product having both a low dielectric constant and a low dielectric loss tangent, high heat resistance (high glass transition temperature), and practical adhesiveness to metals or the like can be obtained.

Brief Description of Drawings

[0016] [Figure 1] FIG. 1 is a 1H-NMR spectrum of a compound represented by the following formula (2) (compound (2)).

Mode for Carrying Out the Invention

[0017] <<Compound>> The compound according to the present invention (hereinafter also referred to as "the present compound") is a compound represented by the following formula (1). The present compound is suitably used, for example, as a crosslinking agent, and in this case, can also be referred to as a phosphine sulfide group-containing crosslinking agent.

[0018] According to the present compound, the reason why the above-described effect is exhibited is not necessarily clear, but can be speculated as follows. The electronegativities of phosphorus (P), sulfur (S), and carbon (C) are C: 2.55, P: 2.19, and S: 2.58, which are close to one another. Accordingly, it is thought that the compound exhibits smaller polarization and lower dielectric constant / dielectric loss tangent than compounds containing oxygen (O, which has an electronegativity of 3.44) or the like. Further, a cured product crosslinked by the present compound, which has a structure with low degrees of freedom having an aromatic ring as the basic skeleton, is considered to have a high glass transition temperature. Furthermore, since the compound contains a sulfur element that exhibits excellent adhesion to metal species, it is considered to also have practical adhesiveness to metals and the like.

[0019]

Chemical Formula

[0020] R 1 to R 15 Examples of the hydrocarbon group having 1 to 20 carbon atoms for include monovalent chain hydrocarbon groups having 1 to 20 carbon atoms, monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, and aromatic hydrocarbon groups having 6 to 20 carbon atoms.

[0021] Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include alkyl groups such as methyl group, ethyl group, propyl group, and butyl group; alkenyl groups such as ethenyl group, propenyl group, and butenyl group; and alkynyl groups such as ethynyl group, propynyl group, and butynyl group.

[0022] Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monovalent monocyclic saturated alicyclic hydrocarbon groups such as cyclopentyl group and cyclohexyl group; monovalent monocyclic unsaturated alicyclic hydrocarbon groups such as cyclopentenyl group and cyclohexenyl group; norbornyl group, adamantyl group, tricyclo[5.2.1.0 2,6 decyl group, tetracyclo[4.4.0.12,5 .1 7,10 ] Monovalent polycyclic alicyclic saturated hydrocarbon groups such as dodecyl groups; norborneyl groups, tricyclo[5.2.1.0 2,6 ]decenyl group, tetracyclo[4.4.0.1 2,5 .1 7,10 Examples include monovalent polycyclic alicyclic unsaturated hydrocarbon groups such as dodecenyl groups.

[0023] Examples of monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms include aryl groups such as phenyl, tolyl, xyl, naphthyl, and anthryl groups; and aralkyl groups such as benzyl, phenethyl, naphthylmethyl, and anthrylmethyl groups.

[0024] The aforementioned R 1 ~R 15 At least two of them have ethylenically unsaturated bonds. Specific examples of hydrocarbon groups having an ethylenically unsaturated bond include the aforementioned alkenyl group, alkynyl group, monovalent monocyclic alicyclic unsaturated hydrocarbon group, and monovalent polycyclic alicyclic unsaturated hydrocarbon group.

[0025] The compound represented by the following formula (2) (hereinafter also referred to as "compound (2)") is preferred as the compound.

[0026] [ka]

[0027] <Method for synthesizing this compound> One method for synthesizing this compound, particularly compound (2), is a method that includes a step of reacting tris(4-styryl)phosphine with sulfur (hereinafter also referred to as "step 1"). Tris(4-styryl)phosphine can be obtained by conventionally known methods, for example, by reacting trichlorophosphine with p-vinylphenylmagnesium chloride in the presence of a solvent such as THF, and commercially available products may also be used.

[0028] [ka]

[0029] While there are no particular restrictions on the atmosphere used when carrying out step 1, an inert gas atmosphere such as an argon atmosphere is preferred, for example, because it can suppress side reactions such as oxidation reactions.

[0030] Step 1 is usually carried out in a solvent. Examples of such solvents include hydrocarbon solvents, halogenated hydrocarbon solvents, and ether solvents. Examples of hydrocarbon solvents include toluene, xylene, and mesitylene. Examples of halogenated hydrocarbon solvents include methylene chloride, chloroform, carbon tetrachloride, chlorobenzene, and o-dichlorobenzene. Examples of ether-based solvents include diethyl ether, tetrahydrofuran, and 1,4-dioxane. Among these, toluene is preferred as the solvent. Tris(4-styryl)phosphine and sulfur are highly soluble in toluene, and by carrying out step 1 in the presence of toluene, the reaction in step 1 can be carried out at a relatively high concentration.

[0031] Step 1 may be carried out under heating, but it is preferable to carry it out at room temperature. The compound obtained in step 1, particularly compound (2), may be purified as necessary and then used in curable compositions, etc.

[0032] ≪Curable composition≫ The curable composition according to the present invention (hereinafter also referred to as "the composition") is not particularly limited as long as it contains the compound, and may contain other components other than the compound. The compound used in this composition may be one type or two or more types.

[0033] The content of the compound in this composition is preferably 0.05% by mass or more, more preferably 20% by mass or more, preferably 99.95% by mass or less, and more preferably 70% by mass or less, when the total solid content in this composition is considered to be 100% by mass. When the content of this compound is within the aforementioned range, it is preferable because it can further improve the degree of hardening and mechanical properties of the cured product obtained from this composition.

[0034] This composition can be prepared by mixing the compound and the other components as needed. The compound and the other components as needed may be prepared, for example, by kneading them in the absence of a solvent, or by dissolving or dispersing them in a solvent and then mixing them.

[0035] <Other ingredients> Other components include, for example, curable compounds, curing aids, solvents, polymerization inhibitors to increase stability, antioxidants, inorganic fillers, organic fillers, adhesion aids, lubricants, flame retardants, antibacterial agents, colorants, release agents, and foaming agents. Each of these other ingredients may be used individually or in combination of two or more.

[0036] [Curable compound] The curable compound is a compound other than the present compound, which hardens upon irradiation with heat or light (e.g., visible light, ultraviolet light, near-infrared light, far-infrared light), and may require a curing aid as described later. Examples of such curable compounds include vinyl compounds, maleimide compounds, allyl compounds, methacrylic compounds, benzocyclobutene compounds, and silane compounds. Among these, at least one of styrene compounds and allyl compounds is particularly preferred in terms of compatibility and reactivity with the present compound.

[0037] Examples of the vinyl compounds include compounds having a styrene group represented by the following formulas (3-1) to (3-3), ULL-950S (manufactured by LONZA), 2-vinyl-4,6-diamino-1,3,5-triazine, styrene-butadiene-styrene copolymer (SBS), hydrogenated styrene-butadiene-styrene copolymer, and butadiene polymers.

[0038] [ka] [In equations (3-2) and (3-3), l, m, and n are each independently between 1 and 5000.]

[0039] Examples of the maleimide compounds include compounds containing a maleimide group represented by the following formulas (3-4) to (3-5), BMI6895, BMI1500, and BMI2500 (manufactured by Designer Molecules).

[0040] [ka] [In equation (3-5), n is between 1 and 5000.]

[0041] Examples of the allyl compounds include triallyl isocyanate, 1,2,4-trivinylcyclohexane, L-DAIC, and TA-G (manufactured by Shikoku Chemicals Co., Ltd.).

[0042] Examples of the methacrylic compound include SA-9000 (manufactured by SABIC Corporation), which contains a methacrylic group.

[0043] Examples of the benzocyclobutene compound include the compound described in Japanese Patent Publication No. 2005-60507.

[0044] Examples of the silane compounds include KF-99 (manufactured by Shin-Etsu Chemical Co., Ltd.), KF-9901 (manufactured by Shin-Etsu Chemical Co., Ltd.), dimethylphenylsilane, triethoxysilane, and octahydrooctasilsesquioxane.

[0045] If the composition contains a curable compound, the content of the curable compound is preferably 0.05% by mass or more, more preferably 30% by mass or more, preferably 99.95% by mass or less, and more preferably 80% by mass or less, when the total solid content of the composition is considered to be 100% by mass. When the content of the curable compound is within the aforementioned range, it is preferable from the standpoint that the strength, heat resistance, and chemical resistance of the cured product obtained from this composition can be further improved.

[0046] [Hardening agent] Examples of the curing aids include polymerization initiators such as thermal or photoradical initiators and cationic curing agents.

[0047] Examples of thermal radical initiators include organic peroxides such as dicumyl peroxide, 1,1-di(t-butylperoxy)cyclohexane, di(t-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3, and benzoyl peroxide; and azo compounds such as azobisbutyronitrile, 1,1'-azobis(1-acetoxy-1-phenylethane), 2,2'-azobis(2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-carbonitride), dimethyl-2,2'-azobis(isobutyrate), and 2,2'-azobis(2-methylbutyronitrile).

[0048] Examples of photoradical initiators include benzylmethyldimethyl ketals and hydroxyalkylphenones such as 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, and 2-hydroxy-2-methyl-1-phenylpropan-1-one; α-aminoketone compounds such as 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one and 2-benzylmethyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone; acylphosphine oxide compounds such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; and anthracene compounds such as 2-methyl-9,10-bis(methoxycarbonyloxy)anthracene and 2-methyl-9,10-bis(ethoxycarbonyloxy)anthracene.

[0049] Examples of cationic curing agents include diallylodonium salts, trialkylsulfonium salts, phosphonium salts such as butyltriphenylphosphonium thiocyanate, and boron trifluoride, with BF4, PF6, and SbF6 as counteranions, such as SP70, SP172, and CP66 from ADEKA Corporation, CI2855 and CI2823 from Nippon Soda Co., Ltd., and SI100 and SI150 from Sanshin Chemical Industry Co., Ltd.

[0050] Examples of curing aids when using the silane compound include platinum black, platinum-dic chloride, chloroplatinic acid, reaction products of chloroplatinic acid and monohydric alcohols, complexes of chloroplatinic acid and olefins, platinum-based catalysts such as platinum bisacetate; palladium-based catalysts; rhodium-based catalysts; and other platinum group metal catalysts, zinc benzoate, and zinc octoate.

[0051] If the composition contains a curing aid, the content of the curing aid is preferably within a range that allows the composition to cure well and a cured product to be obtained. Specifically, the content is preferably 0.000001 parts by mass or more, more preferably 0.01 parts by mass or more, preferably 20 parts by mass or less, and more preferably 5 parts by mass or less, based on 100 parts by mass of the total solid content of the compound and the curable compound.

[0052] ≪Cured product≫ The cured product according to the present invention (hereinafter also referred to as "the cured product") is a cured product of the aforementioned composition, and is obtained by curing the aforementioned composition. The cured product may be, for example, a partially cured product of the composition obtained by drying the solvent from the composition.

[0053] The curing method for this composition is not particularly limited, but typically, thermal curing by heating or photocuring by light irradiation are used. These methods can also be used in combination.

[0054] When heat curing is performed, the heating temperature is preferably 50°C or higher, more preferably 150°C or higher, preferably 300°C or lower, and more preferably 250°C or lower. The heating time is preferably 0.1 hours or more, more preferably 1 hour or more, preferably 36 hours or less, and more preferably 3 hours or less.

[0055] When using photocuring, examples of light used include visible light, ultraviolet light, near-infrared light, and far-infrared light.

[0056] While there are no particular restrictions on the atmosphere used to cure this composition, an inert gas atmosphere such as a nitrogen atmosphere or a vacuum atmosphere is preferred.

[0057] The shape of the cured product is not particularly limited and can be any shape suitable for the application and purpose, but a film is one example. The cured product may be a single cured product consisting solely of this composition, or it may be a laminate in which one or both sides are in contact with at least one material selected from metal materials, resin materials, and inorganic materials.

[0058] The lower limit of the glass transition temperature (Tg) of the cured product is preferably 185°C, more preferably 200°C, and the upper limit is, for example, 300°C. Having a Tg within the aforementioned range makes melt molding easier and results in a cured product with excellent heat resistance. The Tg is specifically measured by the method described in the following examples.

[0059] The dielectric constant of the cured product is preferably 3.0 or less, more preferably 2.5 or less, from the viewpoint of reducing transmission loss, and although there is no particular lower limit, it is preferably 1.5 or more. The dielectric loss tangent (tanδ) of this cured product is preferably 0.004 or less, more preferably 0.003 or less, from the viewpoint of reducing transmission loss, and although there is no particular lower limit, it is preferably 0.0005 or more. The dielectric constant and dielectric loss tangent are specifically measured by the method described in the following examples. [Examples]

[0060] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0061] [NMR Spectrum Measurement] The NMR spectrum of the compound obtained in Synthesis Example 1 was measured by dissolving the compound in the deuterated solvent deuterated chloroform and using a nuclear magnetic resonance spectrometer (ECP-300, manufactured by JEOL Ltd.).

[0062] [Synthesis Example 1] Synthesis of Compound (2) Tris(4-styryl)phosphine (manufactured by Hokko Chemical Industry Co., Ltd., 10.21 g, 30.0 mmol) and sulfur (1.92 g, 60 mmol) were weighed into a 200 mL two-necked round-bottom flask containing a magnetic rotor. After being placed under an argon atmosphere, distilled toluene (90 mL) was added. The resulting mixture was stirred at room temperature for 20 hours, and the solvent was removed by distillation. The concentrated residue after solvent removal was purified by silica gel column chromatography (developing solvent: hexane / ethyl acetate = 9 / 1 vol / vol) to obtain compound (2). The yield of the obtained compound (2) was 98.9%.

[0063] The obtained compound (2) 1 The H-NMR spectrum is shown in Figure 1. 1The H-NMR measurement results are shown below. 1 H-NMR (300MHz, CDCl3): δ=5.37(d, J=10.5Hz,3H),5.84(d, J=17.4Hz,3H),6.73(dd,J=16.1Hz,J=11.9Hz,3H),7.47(6H),7.67(6H).

[0064] [Example 1] Compound (2) obtained in Synthesis Example 1, OPE-2St (manufactured by Mitsubishi Gas Chemical Co., Ltd., terminal-modified polyphenylene ether), and DCP (dicumyl peroxide, manufactured by Tokyo Chemical Industry Co., Ltd.) were weighed according to the solid content ratios shown in Table 1. Then, they were diluted with toluene to a solid content concentration of 20% by mass and mixed in a mix rotor to prepare a homogeneous solution, which is a curable composition.

[0065] [Example 2] A curable composition was prepared in the same manner as in Example 1, except that SA-9000 (SABIC Corporation, terminal methacrylate-modified polyphenylene ether) was used instead of OPE-2St.

[0066] [Comparative Examples 1-2] A curable composition was prepared in the same manner as in Example 1, except that TAIC (manufactured by Mitsubishi Chemical Corporation, triallyl isocyanurate) or DVB (manufactured by Nippon Steel Chemical & Materials Corporation, 96% divinylbenzene), as shown in Table 1, was used instead of compound (2).

[0067] [Comparative Example 3] A curable composition was prepared in the same manner as in Example 2, except that DVB was used instead of compound (2).

[0068] <Preparation of hardened film> The curable compositions obtained in Examples 1-2 and Comparative Examples 1-3 were applied to the matte surface of copper foil (CF-V9S-SV) manufactured by Fukuda Metal Co., Ltd. using a baker-type applicator (gap: 125 μm), dried at 100°C for 5 minutes, and then at 130°C for another 5 minutes, to form a coating film approximately 50 μm thick on the copper foil. The resulting coated copper foil and the copper foil (CF-V9S-SV) were bonded together by vacuum pressing at 150°C for 5 minutes, and then baked under nitrogen at 200°C for 2 hours to produce a copper foil laminate. The prepared copper foil laminate was immersed in a 40% by mass iron chloride solution to remove the copper foil from the laminate, washed with water, and dried in an oven at 80°C for 30 minutes to produce a cured film.

[0069] <Appearance of the hardened film> The appearance of the prepared cured film was visually observed, and if no phase separation was visible in the cured film, it was marked with a "○". The results are shown in Table 1.

[0070] <Dielectric constant and dielectric loss tangent> A test specimen (6 cm wide x 6 cm long) was cut from the fabricated cured film, and the dielectric constant and dielectric loss tangent of the specimen at 10 GHz were measured using the cavity resonator method (TE mode resonator, dielectric constant measurement system, manufactured by AET Co., Ltd.). The results are shown in Table 1.

[0071] <Glass transition temperature (Tg)> The curable compositions obtained in Examples 1-2 and Comparative Examples 1-3 were coated onto a 525 μm thick silicon wafer using a spin coater and dried at 100°C for 5 minutes and then at 130°C for 5 minutes to obtain a B-stage film (thickness: 50 μm). The obtained B-stage film was filled into an aluminum pan for DSC measurement and cured at 200°C under nitrogen for 2 hours. The resulting aluminum pan was then placed in a DSC (NETZSCH, DSC 204F1 Phoenix, differential scanning calorimeter), heated at 20°C / min under nitrogen conditions, and the glass transition temperature (Tg) was measured. Tg was defined as the phase transition start temperature. The results are shown in Table 1.

[0072] <Peel strength> A test piece (width: 5 mm × length: 10 cm) was cut from a copper foil laminate prepared by the same method as for the preparation of the cured film described above. Using an "Instron 5567" manufactured by Instron Corporation, the copper foil was pulled at a 90-degree angle at a rate of 500 mm / min, and the peel strength (N / mm) between the copper foil and the layer (cured layer) obtained from the curable composition obtained in Examples 1-2 or Comparative Examples 1-3 was measured in accordance with "IPC-TM-650 2.4.9". The results are shown in Table 1.

[0073] [Table 1]

Claims

1. A compound represented by the following formula (2), A curable compound selected from the compound represented by the following formula (3-3) and terminal methacrylate-modified polyphenylene ethers, and A curable composition containing the following: 【Chemistry 1】 【Chemistry 2】 [In equation (3-3), m and n are each independently between 1 and 5000.]

2. A cured film obtained from the curable composition described in claim 1.

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