Resin composition and adhesive sheet using same

Abstract

To provide a thermal radical reactive resin composition which has a sufficiently low relative dielectric constant and a sufficiently low dielectric loss tangent and is also excellent in heat resistance, and to provide an adhesive sheet using the same.SOLUTION: There is provided a resin composition comprising: a hydrogenated block copolymer composed of styrene and butadiene; a polyphenylene ether copolymer having a terminal modified with a (meth) acryloyl group; a (meth) acrylate having a fluorene skeleton; and an organic peroxide, in which a content of the polyphenylene ether copolymer relative to a total solid content is 15 to 45 wt.%, and a content of the (meth) acrylate having the fluorene skeleton relative to the total solid content is 3 to 12 wt.%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermal radical reactive resin composition having low dielectric properties and high heat resistance, and an adhesive sheet using the same. [Background technology]

[0002] In recent years, electronic devices such as smartphones have rapidly become more powerful and functional, and the materials used in these devices are also being required to have further improvements in their physical properties, such as heat resistance, mechanical strength, and electrical characteristics. For example, printed wiring boards on which semiconductor components, capacitors, etc. are mounted are also being required to have higher density and higher functionality.

[0003] In particular, to accommodate the increased speed of transmission signals required for high-definition, fast-moving videos, electrical properties that can suppress signal delay and transmission loss in the high-frequency range are required, and low dielectric properties such as low dielectric constant and low dielectric loss tangent are required for the constituent materials (e.g., adhesive compositions) of rigid printed wiring boards and flexible printed wiring boards (hereinafter referred to as FPCs) (Patent Document 1).

[0004] Furthermore, in recent years, with the spread of lead-free solder and direct mounting of semiconductor chips, further improvements in heat resistance as well as low dielectric properties are being demanded. Polyphenylene ether is well known as a circuit board material with excellent low dielectric properties, and it also has higher heat resistance than epoxy resin, but this is not sufficient when a glass transition temperature (Tg) of 170°C or higher is required, and there was room for improvement in simultaneously satisfying the two properties of high heat resistance along with the electrical properties of low dielectric constant and low dielectric dissipation factor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-79354 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides a thermal radical reactive resin composition that has a sufficiently low relative dielectric constant and dielectric loss tangent and also has excellent heat resistance, and an adhesive sheet using the same. [Means for solving the problem]

[0007] In order to solve the above problems, the invention of claim 1 comprises a hydrogenated block copolymer (A) made of styrene and butadiene, a polyphenylene ether copolymer (B) whose terminals are modified with (meth)acryloyl groups, a (meth)acrylate having a fluorene skeleton (C), and an organic peroxide (D), (A) is a thermoplastic polymer (SEBS) and / or modified SEBS obtained by hydrogenating a block copolymer composed of a polystyrene block and a polybutadiene, The resin composition is characterized in that the blending amount of (B) is 15 to 45% by weight based on the total solid content, and the blending amount of (C) is 3 to 12% by weight based on the total solid content.

[0008] The invention according to claim 2 provides the resin composition according to claim 1, wherein (C) is a di(meth)acrylate having a 9,9-bisarylfluorene skeleton.

[0009] The invention of claim 3 is or 2 An adhesive sheet for copper-clad laminates is provided using any of the resin compositions described above. [Effects of the Invention]

[0012] The thermal radical reactive resin composition of the present invention has a sufficiently low relative dielectric constant and dielectric loss tangent, and also has excellent heat resistance, and is therefore useful as an insulating resin for rigid printed wiring boards and as a material for adhesives and adhesive sheets used in FPCs. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in detail below.

[0014] The resin composition of the present invention comprises a hydrogenated block copolymer (A) of styrene and butadiene, a polyphenylene ether copolymer (B) whose terminals are modified with (meth)acryloyl groups, a (meth)acrylate having a fluorene skeleton (C), and an organic peroxide (D). In this specification, the term "(meth)acrylate" includes both acrylate and methacrylate.

[0015] The hydrogenated styrene-butadiene block copolymer (A) used in the present invention is a thermoplastic polymer (hereinafter referred to as SEBS: styrene-ethylene-butylene-styrene) that exhibits rubber elasticity over a wide temperature range, and is obtained by hydrogenating a block copolymer consisting of a polystyrene block as a hard segment and a polybutadiene block as a soft segment. Compared to non-hydrogenated styrene-butadiene block copolymer (hereinafter referred to as SBS), it has excellent weather resistance, heat aging resistance, and low-temperature processability.

[0016] Although the (A) may be partially hydrogenated (hereinafter referred to as SBBS: styrene-butadiene-butylene-styrene), fully hydrogenated SEBS is preferred because it has better weather resistance and heat resistance and also has improved compatibility with (B) and (C). Furthermore, amine- or acid-modification tends to improve the elongation percentage when formed into a sheet, making it particularly preferred. With unhydrogenated SBS, there are concerns that compatibility with (B) and (C) may be reduced and adhesive strength may decrease over time. Commercially available SEBS products include the Tuftec H series (trade name: Asahi Kasei Corporation, SEBS), the M series (maleic acid-modified SEBS), and the MP series (amine-modified SEBS).

[0017] The styrene ratio of (A) is preferably 15 to 70% by weight, more preferably 18 to 40% by weight, and particularly preferably 20 to 35% by weight. By making it 15% by weight or more, sufficient tensile strength can be ensured, and by making it 70% by weight or less, sufficient elastic force can be ensured.

[0018] The ratio of (A) to the total solid content is preferably 20 to 80% by weight, more preferably 25 to 75% by weight, and particularly preferably 28 to 72% by weight. By making it 20% by weight or more, sufficient cohesive strength can be ensured when made into a sheet, and by making it 80% by weight or less, sufficiently low dielectric properties and high Tg can be ensured.

[0019] The polyphenylene ether (hereinafter referred to as PPE) copolymer (B) used in the present invention, the terminals of which are modified with (meth)acryloyl groups, has a structure in which the hydroxyl groups present at the terminals of the PPE main chain are modified with (meth)acryloyl, and has higher heat resistance than epoxy resins commonly used in rigid printed wiring boards, and is blended with the aim of improving dielectric properties.

[0020] The (B) can be represented by, for example, the following general formula [1]. [ka] [1] (In the formula, R1 to R7 each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms; Y represents an oxygen atom, a methylene group, or a dimethylmethylene group; Z represents a carbonyl group, a thiocarbonyl group, or a methylene group; n represents an integer of 1 to 100; and m represents an integer of 1 to 100.)

[0021] In the (B) above, it is preferable that R1 to R7 in the general formula (1) above are each independently a hydrogen atom or a methyl group, Y is preferably a dimethylmethylene group, and Z is preferably a carbonyl group. Commercially available products include Noryl SA9000 and SA6000 (trade names: manufactured by SABIC).

[0022] The ratio of (B) to the total solid content is 15 to 45 wt%, preferably 17 to 43 wt%, and particularly preferably 18 to 40 wt%. If it is less than 15 wt%, it is difficult to ensure sufficiently low dielectric properties, and if it exceeds 45 wt%, the compatibility balance is lost and separation may occur during film formation.

[0023] The (meth)acrylate (C) having a fluorene skeleton used in the present invention is blended for the purpose of improving the Tg of the cured composition. Fluorene is an aromatic hydrocarbon having a three-ring structure, and in particular, in the case of a 9,9-bisarylfluorene skeleton with a benzene ring bonded thereto, it forms a bulky cardo (hinge) structure, and due to the presence of many aromatic rings, it has properties such as a high refractive index, high heat resistance, low shrinkage, and low birefringence, which are desirable. The number of functional groups is preferably tetrafunctional or less, and more preferably 2functional or less, in order to avoid excessively increasing the rigidity of the cured product.

[0024] The di(meth)acrylate having a 9,9-bisarylfluorene skeleton can be represented by, for example, the general formula [2]. JPEG0007759776000002.jpg37135...Formula[2] (In the formula, R1 and R2 each independently represent a hydrogen atom or a methyl group, L1 and L2 each independently represent a phenylene group which may have a substituent, L3 and L4 each independently represent an alkylene group having 1 to 6 carbon atoms, and m and n each represent an integer satisfying 0≦m≦40, 0≦n≦40, and 0≦m+n≦40.)

[0025] Examples of commercially available products of (C) include Ogusol EA-0200, EA-0300, and EA-F5710 (trade names: manufactured by Osaka Gas Chemicals Co., Ltd.) Among these, Ogusol EA-0200 (9,9-bis(4-acryloyloxyethoxyphenyl)fluorene) is preferred because it has a Tg of 200°C or higher, high heat resistance, and good availability.

[0026] The proportion of (C) to the total solid content is 3 to 12% by weight, preferably 3.2 to 11% by weight, and more preferably 3.5 to 10.5% by weight. If it is less than 3% by weight, the Tg of the cured product does not increase significantly, and heat resistance is not sufficiently ensured. If it exceeds 12% by weight, it becomes difficult to sufficiently lower the dielectric loss tangent.

[0027] The organic peroxide (D) used in the present invention is blended as a radical polymerization initiator. (D) may be any organic peroxide that functions as a known radical initiator. Examples include di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxide)hexane, 2,5-dimethyl-2,5-di(t-butylperoxide)hexyne-3, t-butylcumyl peroxide, α,α'-di-(t-butylperoxy)diisopropylbenzene, and t-butyl peroxybenzoate. These can be used alone or in combination of two or more. Commercially available products include Perbutyl P and Perbutyl D (trade names: manufactured by NOF Corporation).

[0028] The ratio of (D) to the total of 100 parts by weight of the radical reaction components (B) and (C) is preferably 1 to 10 parts by weight, more preferably 2 to 5 parts by weight. By adjusting the amount within this range, sufficient curability can be ensured without excessive addition.

[0029] In the present invention, it is preferable to further incorporate a hydrogenated block copolymer (E) containing styrene and ethylene. (E) is expected to improve dielectric properties and increase elongation when formed into a sheet. Examples of (E) include hydrogenated styrene-ethylene / propylene diblock copolymers, hydrogenated styrene-ethylene-ethylene / propylene-styrene block copolymers (hereinafter referred to as SEEPS), and hydrogenated styrene-ethylene / propylene-styrene block copolymers (hereinafter referred to as SEPS). These can be used alone or in combination of two or more. Among these, SEEPS and SEPS are preferred due to their excellent compatibility with (A) and (C). Commercially available products include the Septon 2000 series (product name: SEPS, manufactured by Kuraray Co., Ltd.) and the Septon 4000 series (SEEPS). Ethylene / propylene indicates that the copolymerized portion of ethylene and propylene is a random copolymer, not a block copolymer.

[0030] The styrene ratio of (E) is preferably 15 to 40% by weight, more preferably 18 to 35% by weight. By making it 15% by weight or more, sufficient elongation can be ensured, and by making it 40% by weight or less, gelation can be suppressed and sufficient storage stability can be ensured.

[0031] The ratio of (E) to the total solid content is preferably 0 to 50% by weight, more preferably 15 to 45% by weight, and particularly preferably 20 to 35% by weight. By making it 15% by weight or more, sufficient elongation can be ensured, and by making it 50% by weight or less, compatibility is not reduced and sufficient storage stability can be ensured.

[0032] The resin composition of the present invention may contain additives such as silane coupling agents, antioxidants, inorganic fillers, organic fine particles, flame retardants, ultraviolet absorbers, and light stabilizers, as needed, within limits that do not impair performance.

[0033] The silane coupling agent has functional groups that bond with both organic and inorganic materials within its molecule and is incorporated to improve mechanical strength and adhesion. Examples of functional groups that react with organic materials include vinyl groups, epoxy groups, amino groups, methacrylic groups, and mercapto groups, while hydrolyzable silyl groups react with inorganic materials. Among these, oligomer types with epoxy functional groups are preferred because they have high heat resistance and low volatility due to their large molecular weight and bulky structure, while types with an isocyanurate backbone are highly effective in improving adhesion and heat resistance. Commercially available products of the former include COATOSIL MP 200 (trade name: Momentive), and commercially available products of the latter include KBM9659 (trade name: Shin-Etsu Chemical). The amount of silane coupling agent incorporated is preferably 0.1 to 5 wt. % of the total solids content, and more preferably 0.5 to 3.0 wt. %.

[0034] The incorporation of the antioxidant can prevent deterioration of the physical properties of the film after curing. Examples of antioxidants include phenol-based, phosphorus-based, phenol-phosphorus-based, and sulfur-based antioxidants, which can be used alone or in combination of two or more. The amount of antioxidant incorporated is preferably 5% by weight or less, more preferably 2% by weight or less, based on the total solid content. Commercially available products include Sumilizer GP (trade name: manufactured by Sumitomo Chemical Co., Ltd., phenol-phosphorus-based).

[0035] The composition of the present invention can be dissolved in a compatible solvent such as toluene, applied in solution to a substrate film, dried, and then laminated with a protective film to form a laminate sheet with a three-layer structure of substrate film / adhesive layer / protective film. The thickness of the adhesive layer is, for example, 10 to 50 μm, but is not particularly limited and can be freely set depending on the application and type of adherend. The substrate film and protective film to which the composition is applied are not particularly limited as long as they are later peelable, but release-treated polyethylene terephthalate film (hereinafter referred to as release PET) is preferred in terms of availability, cost, and processability during coating and lamination.

[0036] The present invention will be described in detail below based on examples and comparative examples, but these are illustrative examples and are not intended to be limiting. Unless otherwise specified, measurements were taken at a room temperature of 25°C and a relative humidity of 65%. The blend amounts are in parts by weight.

[0037] Example 1 In a container, Tuftec MP10 (trade name: manufactured by Asahi Kasei Corporation) was added as (A). Amine ModificationThe resin composition of Example 1 was prepared by adding SEBS (styrene ratio: 30%), NORYLSA9000 (trade name: manufactured by SABIC) as (B), OGSOL EA-0200 (trade name: manufactured by Osaka Gas Chemicals Co., Ltd., 9,9-bis(4-acryloyloxyethoxyphenyl)fluorene, Tg 211°C) as (C), PERBUTYL P (trade name: manufactured by NOF Corporation, α,α'-di(t-butylperoxy)diisopropylbenzene) as (D), COATOSIL MP200 (trade name: manufactured by Momentive Corporation, oligomer type having epoxy functional groups) and KBM9659 (trade name: manufactured by Ichinetsu Chemical Co., Ltd., isocyanurate skeleton) as silane coupling agents, and Sumilizer GP (trade name: manufactured by Sumitomo Chemical, phenol-phosphorus antioxidant) as an antioxidant in the amounts shown in Table 1, and then adding toluene so that the solids content was 20%, and mixing and stirring were performed.

[0038] Examples 2 to 8, Comparative Examples 1 to 6 In addition to the materials used in Example 1, Tuftec H1041 (trade name: manufactured by Asahi Kasei Corporation) was used as (A). SEBS styrene ratio 30%), and Septon 4044 (trade name: SEEPS, manufactured by Kuraray Co., Ltd., styrene ratio 32%) as (E) in the amounts shown in Table 1 for the examples and Table 2 for the comparative examples. Toluene was further added so that the solid content was 20%, and the mixture was stirred to prepare the resin compositions of Examples 2 to 8 and Comparative Examples 1 to 6.

[0039] Creating an adhesive sheet for evaluation The resin composition obtained above was uniformly applied onto a release PET film (50 μm) so that the thickness after drying was 25 μm, and then dried in an oven at 80°C for 5 minutes to volatilize the toluene. Release PET films with different peel strengths were then bonded together to create an adhesive sheet (uncured).

[0040] Preparation of evaluation laminates The release film on one side of the adhesive sheet prepared above was peeled off, and the sheet was then bonded to a 50 μm thick Kapton 200H (product name: Toray DuPont, polyimide film) at 100°C and 0.2 MPa. The remaining release film was peeled off, and the sheet was then bonded to the smooth surface of a 12 μm thick copper foil CF-T9FZ-HS-12 (product name: Fukuda Metal Foil and Powder Co., Ltd.) at 120°C and 0.2 MPa. The adhesive layer was then cured at 180°C, 0.3 MPa, and 1 hour to produce a laminate.

[0041] [Table 1]

[0042] [Table 2]

[0043] The evaluation method was as follows.

[0044] Dielectric constant: The uncured adhesive sheet prepared above was cured under conditions of 180°C, 0.3 MPa, and 1 hour to prepare a measurement sample. Using an Anritsu network analyzer MS46122B and an AET measurement resonator 10 GHz TE mode, the dielectric constant was measured at a frequency of 10 GHz and a measurement temperature of 25°C, with a value of 3.0 or less being rated as good and a value of over 3.0 being rated as bad.

[0045] Dielectric loss tangent: The same sample as that for the relative dielectric constant was measured using the same measuring device at a frequency of 10 GHz and a measurement temperature of 25°C. A value of 0.004 or less was marked as ◯, and a value of more than 0.004 was marked as ×.

[0046] Peel strength: The laminate prepared above was cut to a width of 10 mm and a length of 150 mm, and the 90° peel strength of the copper foil was measured using a tensile tester TGI-1kN manufactured by Minebea Co., Ltd. at a crosshead speed of 50 mm / min. and a measurement temperature of 25°C, with a score of 0 for scores of 1.0 N / mm or more and 0 for scores of less than 1.0 N / mm.

[0047] Glass transition point: Using a TA Instruments Q800 dynamic viscoelasticity measuring device, measurements were taken at a heating rate of 3°C / min and a frequency of 1 Hz using a test piece made to be 40 mm x 5 mm x 1 mm thick. The top of the Tan Δ peak was taken as the glass transition point, with values ​​below 170°C marked x and values ​​above 170°C marked ◯.

[0048] Evaluation results The evaluation results are shown in Tables 3 and 4.

[0049] [Table 3]

[0050] [Table 4]

[0051] The resin compositions of the examples obtained good results in all of the evaluation items of relative permittivity, dielectric loss tangent, peel strength, and Tg.

[0052] On the other hand, Comparative Example 1, which did not contain (A), had poor compatibility and gelled, and Comparative Example 2, which did not contain (C), Comparative Example 3, in which (C) was below the lower limit, and Comparative Example 5, in which (B) was below the lower limit, all had low Tg. Furthermore, Comparative Example 4, in which (C) was above the upper limit, had a high dielectric loss tangent, and Comparative Example 6, in which (B) exceeded the upper limit, separation occurred during film formation, and none of these were suitable for the present invention.

Claims

1. A resin composition comprising (A) a hydrogenated block copolymer of styrene and butadiene, (B) a polyphenylene ether copolymer terminally modified with a (meth)acryloyl group, (C) a (meth)acrylate having a fluorene skeleton, and (D) an organic peroxide, wherein (A) is a thermoplastic polymer (SEBS) and / or modified SEBS obtained by hydrogenating a block copolymer consisting of a polystyrene block and a polybutadiene, and the blending amount of (B) relative to the total solid content is 15 to 45 wt %, and the blending amount of (C) relative to the total solid content is 3 to 12 wt %.

2. 2. The resin composition according to claim 1, wherein the component (C) is a di(meth)acrylate having a 9,9-bisarylfluorene skeleton.

3. 3. An adhesive sheet for copper-clad laminates, which uses the resin composition according to claim 1.

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