Resin solution, and cured product thereof, and method for producing the same

Abstract

To control the oozing of a solution applied during lamination processing.SOLUTION: A solution comprises: a copolymer containing at least a monomer unit based on styrene and a monomer unit based on divinylbenzene; and an organic filler dispersed in a solvent, wherein the solution exhibits a haze value of 8% or more and 50% or less as measured in accordance with JIS K7136:2000 and JIS K7361-1:1997.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin solution having a predetermined transparency, a cured product thereof, and a method for producing the same.

Background Art

[0002] Aromatic copolymers are substances that are often used in the manufacturing process of electronic devices by taking advantage of their low dielectric properties. Aromatic copolymers are often distributed, stored, and used in the form of a solution with an emphasis on ease of work.

[0003] For example, Patent Document 1 discloses a curable resin composition containing a modified polyphenylene ether, a styrene-based elastomer, and a crosslinking aid that is an aromatic vinyl compound such as 4-tert-butylstyrene or divinylbenzene, and having a solution viscosity measured by a cone-plate type rotational viscometer of 1 to 7000 mPa·s for a toluene solution with a solid content concentration of 62%. By having a specific viscosity when dissolved in a specific solvent, it is easy to impregnate a base material during substrate production, and it is claimed to satisfy all of the sufficient low dielectric properties, low linear expansion coefficient, and high copper foil adhesion strength of the cured product.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Some components of electronic devices require lamination (laminate) processing, and an aromatic copolymer solution may be applied for laminating the layers. However, with the solutions according to the prior art, there is a problem that bleeding occurs during the processing. In particular, when producing a resin sheet in the B-stage state, the compounding solution in the middle of drying flows out from the frame, resulting in bleeding of the compounding solution, and problems such as thickness defects of the B-stage resin sheet and poor dispersion of silica may occur.

Means for Solving the Problems

[0006] That is, the following can be provided in the embodiments of the present invention.

[0007] Aspect 1. A copolymer containing at least a monomer unit based on styrene and a monomer unit based on divinylbenzene, an organic filler dispersed in a solvent, and A solution containing, The haze value of the solution measured in accordance with JIS K7136:2000 and JIS K 7361-1:1997 is in the range of 8% or more and 50% or less. A solution characterized by this.

[0008] Aspect 2. The solution according to Aspect 1, wherein the organic filler contains polystyrene.

[0009] Aspect 3. The solution according to Aspect 1 or 2, wherein the organic filler is composed of spherical particles.

[0010] Aspect 4. A copolymer containing at least a monomer unit based on styrene and a monomer unit based on divinylbenzene, a solvent, and A solution containing, A part of the copolymer forms particles crosslinked with each other and is dispersed in the solvent. The haze value of the solution, measured in accordance with JIS K7136:2000 and JIS K 7361-1:1997, is in the range of 8% or more and 50% or less. A solution, characterized by this.

[0011] Aspect 5. The solution according to any one of Aspects 1 to 4, wherein the solvent contains toluene.

[0012] Aspect 6. The solution according to any one of Aspects 1 to 5, wherein the solid content concentration of the solution is in the range of 10% by mass or more and 50% by mass or less.

[0013] Aspect 7. The solution according to any one of Aspects 1 to 6, wherein the copolymer further contains one or more monomer units based on ethylene or butadiene.

[0014] Aspect 8. The solution according to any one of Aspects 1 to 7, and one or more additive components selected from the group consisting of a resin component, a curing agent, a monomer, a flame retardant, and a surface modifier A non-liquid composition containing the same.

[0015] Aspect 9. A cured body obtained by substantially removing the solvent from the solution according to any one of Aspects 1 to 7.

[0016] Aspect 10. A cured body of the composition according to Aspect 8.

[0017] Aspect 11. A step of preparing a copolymer containing at least a monomer unit based on styrene and a monomer unit based on divinylbenzene, a step of obtaining a solution containing the copolymer, an organic filler, and a solvent, a step of forming particles composed of the organic filler in the solvent so that the haze value of the solution, measured in accordance with JIS K7136:2000 and JIS K 7361-1:1997, is in the range of 8% or more and 50% or less A method for producing a solution, comprising:

[0018] Aspect 12. The step of obtaining the solution includes adding the copolymer and the organic filler to the solvent The production method according to aspect 11, comprising:

[0019] Aspect 13. The step of preparing the copolymer includes constituting the styrene-based monomer unit and the organic filler respectively based on the styrene monomer as a raw material The production method according to aspect 11, comprising:

[0020] Aspect 14. preparing a copolymer containing at least a styrene-based monomer unit and a divinylbenzene-based monomer unit; making a part of the copolymer into crosslinked particles; adding the crosslinked particles and the remainder of the copolymer into a solvent to make the haze value measured in accordance with JIS K7136:2000 and JIS K 7361-1:1997 of the solution in the range of 8% or more and 50% or less; A method for producing a solution, comprising:

Advantages of the Invention

[0021] According to the embodiments of the present invention, an effect of suppressing bleeding of the solution applied during lamination can be obtained.

Modes for Carrying Out the Invention

[0022] In this specification, unless otherwise specified, the "copolymer" refers to a copolymer having monomer units based on at least styrene and divinylbenzene respectively. The "monomer unit" constituting the copolymer in this specification means a component derived from (induced from) the monomer. Numerical ranges in this specification include their upper and lower limit values unless otherwise stated.

[0023] [Physical properties of the solution] The solution according to an embodiment of the present invention is a liquid having a specific turbidity, characterized in that the haze value measured in accordance with JIS K7136:2000 and JIS K 7361-1:1997 is in the range of 8% or more and 50% or less. The haze value of this solution may preferably be in the range of 8% or more and 40% or less, more preferably 9% or more and 37% or less. This solution can be used in the form of a sheet applied or partially cured in the manufacturing process of electronic devices. This solution can be cured alone or by adding some known curing agent by substantially removing the solvent (removing so that only a trace amount of the solvent remains). In certain embodiments, a cured body obtained in this way can also be provided. Adjustment of the haze value is possible, for example, by adding an organic filler or a solution or dispersion of an organic filler to the solution of the copolymer. Alternatively, adjustment of the haze value can also be achieved by adding an organic filler in advance to the reaction system for producing the copolymer.

[0024] [Solution according to the first embodiment] The solution according to the first embodiment of the present invention contains a copolymer and an organic filler, which will be described later, in a solvent. Preferably, the solid content concentration of this solution may be in the range of 10% by mass or more and 50% by mass or less, more preferably in the range of 15% by mass or more and 45% by mass or less, and even more preferably in the range of 20% by mass or more and 40% by mass or less. In this specification, the "solid content concentration" refers to the ratio of the solid content to the liquid, that is, the concentration of the solute contained in the solvent. Specifically, the solid content concentration may be considered as the concentration calculated from the total mass of the copolymer and the organic filler, which will be described later. In this specification, the solid content concentration is based on mass (mass%, which may sometimes be represented by wt%) unless otherwise specified.

[0025] [A copolymer containing at least a monomer unit based on styrene and a monomer unit based on divinylbenzene] The copolymer according to the present invention is obtained by copolymerizing at least the monomers of styrene and divinylbenzene. This copolymer may be a copolymer consisting only of monomer units based on styrene and divinylbenzene respectively, or may be a copolymer having other monomer units (for example, monomer units based on aliphatic α-olefins or alicyclic olefins). The content of each monomer unit in the copolymer can be measured by known methods, for example, by NMR measurement described in International Publication No. 2021 / 112087.

[0026] The content of the monomer unit based on styrene in this copolymer (hereinafter, also simply referred to as "styrene monomer unit". The same applies to other types of monomer units.) is more than 0% by mass based on the mass of the entire copolymer, preferably more than 0% by mass and 50% by mass or less, more preferably more than 0% by mass and 30% by mass or less, and even more preferably more than 0% by mass and 10% by mass or less. When the content of the styrene monomer unit is 50% by mass or less, an effect of easily increasing the glass transition temperature of the copolymer can be obtained.

[0027] The content of the divinylbenzene monomer unit in the copolymer is more than 0% by mass based on the mass of the entire copolymer, preferably more than 0% by mass and 20% by mass or less, more preferably more than 0% by mass and 10% by mass or less.

[0028] The copolymer may further have monomer units based on olefins (preferably non-aromatic olefins), preferably monomer units based on aliphatic olefins, alicyclic olefins, or non-vinyl condensed aromatic monoolefins, or combinations thereof.

[0029] The aliphatic olefin monomer that is the source of the aliphatic olefin monomer unit as an optional additive component may be one or more selected from aliphatic olefins having 2 to 20 carbon atoms, such as ethylene, butadiene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene, 3,5,5-trimethyl-1-hexene, etc., and preferably may be ethylene or butadiene or a combination thereof. The content of the aliphatic olefin monomer unit in the copolymer is preferably more than 0% by mass and 70% by mass or less, more preferably 1% by mass or more and 70% by mass or less, and even more preferably 5% by mass or more and 60% by mass or less. When the content of the aliphatic olefin monomer unit is 60% by mass or less, the effect of easily keeping the glass transition temperature of the copolymer within a preferable range can be obtained. When the content of the aliphatic olefin monomer unit is large (for example, 5% by mass or more), the effect that the copolymer and its cured product are less likely to become brittle can be obtained.

[0030] The alicyclic olefin monomer that is the source of the alicyclic olefin monomer unit as an optional additive component may be one or more monomers selected from cyclic olefins (alicyclic olefins) having 7 to 30 carbon atoms, has one or more alicyclic structures in the molecule, and has a polymerizable vinyl group, vinylene group, or vinylidene group. Preferred alicyclic olefins are preferably alicyclic olefins having a hydrocarbon ring structure without heteroatoms. Examples of preferred alicyclic olefins include cyclobutene, cyclopentene, cyclooctene, dicyclopentadiene, and norbornenes. Norbornenes are monomers selected from norbornene and substituted norbornene. Norbornene can be synthesized, for example, by the Diels-Alder reaction of ethylene and cyclopentadiene. Examples of substituted norbornenes include dimethanooctahydronaphthalene (DMON), trimethanododecahydroanthracene (TMDA), phenylnorbornene (5-phenylbicyclo[2.2.1]hept-2-ene), indanyl norbornene (1,4-methano-1,9a,4,4a-tetrahydrofluorene), which is the Diels-Alder reaction product of cyclopentadiene and indene, and methylphenyl norbornene (MPNB, 5-methyl-5-phenylbicyclo[2.2.1]hept-2-ene), which is the Diels-Alder reaction product of cyclopentadiene and α-methylstyrene. These substituted norbornenes are specifically described, for example, in International Publication No. 2006 / 118261, Japanese Patent Application Laid-Open No. 11-504669, and Japanese Patent Application Laid-Open No. 2005-239975. The content of the alicyclic olefin monomer unit that may be included in the copolymer is arbitrary, but is preferably more than 0% by mass and 50% by mass or less, more preferably more than 0% by mass and 30% by mass or less.

[0031] Examples of the condensed aromatic monovinylene compound monomer that is the source of the condensed aromatic monovinylene compound monomer unit as an optional additive component include acenaphthylene, fluorenoo olefin (fluorene derivative), indenofluorene, indene, phenalene, acephenanthrylene, and aceanthrylene.

[0032] The number average molecular weight of the copolymer may be arbitrary, but is preferably 500 or more and 100,000 or less, more preferably 500 or more and 30,000 or less, still more preferably 500 or more and 15,000 or less, and yet more preferably 500 or more and 12,000 or less. The lower the number average molecular weight of the copolymer, the easier it is to obtain the effect of reducing the viscosity in the form of a solution (varnish) in which the copolymer is dissolved in a solvent. Further, when the number average molecular weight of the copolymer is 500 or more, an effect of facilitating the molding process as a thermoplastic resin when cured from the solution can be obtained. In this specification, the number average molecular weight (Mn) and the weight average molecular weight (Mw) can be measured by a known GPC (gel permeation chromatography) method.

[0033] Specific examples of the copolymer include, in addition to styrene-divinylbenzene copolymer, ethylene-styrene-divinylbenzene copolymer, butadiene-styrene-divinylbenzene copolymer, ethylene-ace naphthylene-styrene-divinylbenzene copolymer, ethylene-norbornene-ace naphthylene-styrene-divinylbenzene copolymer, ethylene-ace naphthylene-ethylvinylbenzene-divinylbenzene copolymer, ethylene-ace naphthylene-ethylvinylbenzene-divinylbenzene copolymer, ethylene-propylene-ace naphthylene-divinylbenzene copolymer, 1-octene-norbornene-styrene-divinylbenzene copolymer, or combinations thereof.

[0034] [Organic filler] The organic filler contained in the solution according to the embodiment of the present invention is an organic substance different from the above copolymer and is distinguished as being dispersed in a solvent. Examples of the organic filler include thermoplastic resin particles, thermosetting resin particles, rubber particles, composite particles (core-shell type particles), or combinations thereof, on the premise that they are substances different from the above copolymer, and are preferably homopolymers.

[0035] Examples of the materials for the above-mentioned thermoplastic resin particles include polyolefins (such as polyethylene, polypropylene, ethylene-propylene rubber, etc.), polyamides, polyesters, ABS resins, or combinations thereof.

[0036] Examples of the materials for the above-mentioned thermosetting resin particles include polymethyl methacrylate, polycarbonate, phenol resin, epoxy resin, fluororesin, silicone resin, polyacrylonitrile (PAN) resin, or combinations thereof.

[0037] Examples of the materials for the above-mentioned rubber particles include elastomer resins (such as olefin-based elastomers, acrylic-based elastomers, etc.), fluororubbers, silicone rubbers, or combinations thereof.

[0038] Examples of the above-mentioned composite particles include particles having as a core any of the above-mentioned materials or a material such as silica, and provided thereon with a shell (such as nickel, silica, etc.).

[0039] In one embodiment, the organic filler may be a homopolymer of any of the monomers that form the above copolymer, and from the viewpoint of being easy to suppress bleeding, for example, a system containing polystyrene or polystyrene alone may be used.

[0040] The organic filler is particles dispersed in the solution, and its shape can be arbitrarily adjusted. Examples thereof include ellipsoids, flakes, hollow structures, porous structures, polyhedral spheres, and potato-like convex and concave spheres. Preferably, the shape may be spherical particles or substantially spherical particles. The size of the organic filler can also be arbitrarily set, but it is preferably such that the solution is likely to be turbid due to Mie scattering. For example, it may be in the range of 1 μm to 100 μm in major axis, and more preferably in the range of 1 μm to 30 μm.

[0041] The shape and size of the organic filler can be confirmed by known methods, for example, it can be confirmed by electron microscope observation. Note that the above copolymer may preferably be dissolved in a solution, and in this respect, it can also be distinguished from the organic filler. Since the organic filler is dispersed in this solution, when performing a lamination process involving a step of applying this solution, it is considered that an effect of easily suppressing bleeding from the laminate can be obtained.

[0042] Although it is a hypothesis, it is considered that because the organic filler is dispersed in the solvent as particles of a certain size, when removing the solvent by sandwiching it during lamination and curing, the particles of the organic filler function like a barrier, resulting in an effect of making it difficult for bleeding to occur.

[0043] [Solvent] The solvent constituting the solution according to the embodiment of the present invention may be any one that can dissolve the above copolymer, but is preferably an organic solvent, for example, toluene, ethylbenzene, benzene, xylene, cyclohexane, cyclohexanone, tetrahydrofuran (THF), acetone, methyl ethyl ketone (MEK), acetonitrile, N,N-dimethylformamide (DMF), ethyl acetate, or a combination thereof. More preferably, the solvent may be a system containing toluene or toluene alone. The quantitative ratio of the solvent to the solute (copolymer and organic filler) is determined as the solid content concentration described above and may be arbitrarily set according to the purpose of use.

[0044] [Solution according to the second embodiment] The solution according to the second embodiment of the present invention contains the above-described copolymer and the above-described solvent, and is characterized in that a part of the copolymer constitutes particles crosslinked with each other, and the crosslinked particles are dispersed in the solvent. Note that there may be a plurality of types of the copolymer. For example, it should be noted that an aspect in which the first type of copolymer is dissolved and the second type of copolymer different from the first type forms crosslinked particles is also included in this second embodiment.

[0045] This solution can also achieve the above-described effects by crosslinked particles dispersed in a solvent. The shape and size of the crosslinked particles can also be arbitrarily set and can be selected in the same manner as those of the above-described organic filler, and may preferably be spherical or substantially spherical particles. The solid content concentration of this solution can also be adjusted in the same manner as that of the first embodiment.

[0046] [Method for producing a solution] The solution according to the first embodiment of the present invention can be produced by a method including a step of preparing a copolymer containing at least a monomer unit based on styrene and a monomer unit based on divinylbenzene, a step of obtaining a solution containing the prepared copolymer, an organic filler, and a solvent, and a step of forming particles made of the organic filler in the solvent to make the haze value of the solution within the above-described range.

[0047] In preparing the solution, the copolymer and the organic filler may be added to the solvent.

[0048] Alternatively, in preparing the copolymer, based on the styrene monomer as a raw material of the copolymer, both the monomer unit based on styrene for the copolymer and the organic filler may be respectively configured. That is, it is also possible to obtain the organic filler as a by-product from the process of preparing the copolymer.

[0049] The solution according to the second embodiment of the present invention can be produced by a method including a step of preparing a copolymer containing at least a monomer unit based on styrene and a monomer unit based on divinylbenzene, a step of making a part of the copolymer into crosslinked particles, and a step of adding the crosslinked particles and the remaining part of the copolymer in a solvent to make the haze value of the solution within the above-described range.

[0050] In preparing the solution, a separately crosslinked copolymer may be added to the solution of the uncrosslinked copolymer. Alternatively, a part of the copolymer may be crosslinked (gelated) in the solution.

[0051] [Composition containing a solution] In some embodiments, a non-liquid composition (in the form of a solid, slurry, gel, etc.) containing the above-described solution and an additive component described below can also be provided. It should be noted that in this composition, the solution does not necessarily have to be in a liquid form. For example, it can be a slurry or a solid in a state mixed with the additive component. The additive component is distinguished as a component that is added later to the solution to form a non-liquid composition (a composition that is not a solution), different from the above-mentioned copolymer and organic filler. The above additive component may be a resin component, a curing agent, a monomer, a flame retardant, a surface modifier, or a combination thereof, which will be described later.

[0052] [Resin component] As the resin component, any resin can be used as long as it does not impair the effects brought about by the present invention. Preferably, a hydrocarbon-based elastomer, a polyether-based resin, an aromatic polyene-based resin, or a combination thereof can be used. The addition amount of the resin component may preferably be in the range of 1 to 500 parts by mass, more preferably 1 to 300 parts by mass, based on 100 parts by mass of the above copolymer.

[0053] [Hydrocarbon-based elastomer] The number average molecular weight of the hydrocarbon-based elastomer is preferably 20,000 or more, more preferably 30,000 or more. Examples of the hydrocarbon-based elastomer include one or more elastomers selected from ethylene-based or propylene-based elastomers, conjugated diene-based polymers, aromatic vinyl compound-conjugated diene-based block copolymers or random copolymers, and hydrides (hydrogenated products) thereof. Examples of the ethylene-based elastomer include ethylene-α-olefin copolymers such as ethylene-octene copolymer and ethylene-1-hexene copolymer, EPR, and EPDM. Examples of the propylene-based elastomer include atactic polypropylene, polypropylene with low stereoregularity, and propylene-α-olefin copolymers such as propylene-1-butene copolymer. These hydrocarbon-based elastomers described above may be modified by introducing functional groups with maleic anhydride or other compounds. Among the hydrocarbon-based elastomers, conjugated diene-based polymers are preferred.

[0054] [Conjugated diene polymer] Examples of the conjugated diene polymer include polybutadiene and 1,2-polybutadiene, and 1,2-polybutadiene is preferred. Examples of the aromatic vinyl compound-conjugated diene block copolymer or random copolymer, and their hydrogenated products (hydrogenated products) include SBS, SIS, SEBS, SEPS, SEEPS, SEEBS, etc. The 1,2-polybutadiene that can be preferably used can be obtained, for example, as a product of JSR Corporation, and also from Nippon Soda Co., Ltd. under the product names of liquid polybutadiene: B-1000, 2000, 3000. Further, an example of the copolymer containing the 1,2-polybutadiene structure that can be preferably used is "Ricon100" of TOTAL CRAY VALLEY. These conjugated diene polymers and their hydrogenated products described above may be modified by introducing functional groups with maleic anhydride or other compounds. Among the conjugated diene polymers, conjugated diene copolymers are preferred. Among these conjugated diene copolymers, the hydrogenated products of block copolymers such as SEBS, SEPS, SEEPS, SEEBS, etc. are useful as compatibilizers between the above copolymers and other resin components. These can be obtained from Asahi Kasei under the trade name Tough Tech, or SOE-SS, from Kuraray under the trade name Septon, and from KRATON under the trade name Kraton.

[0055] [Polyether resin] Examples of the polyether resin include polyphenylene ether and polyether. As the polyphenylene ether having a functional group, it is preferable that the molecular terminals are modified with a functional group. Further, in the case of addition for the purpose of curing the composition of the present invention, it is preferable to have a plurality of functional groups in one molecule. For example, it is preferable to use a modified polyphenylene ether. Examples of the functional group include a radically polymerizable functional group and a functional group such as an epoxy group, and preferably a radically polymerizable functional group. As the radically polymerizable functional group, a vinyl group is preferable. As the vinyl group, one or more selected from the group consisting of an allyl group, a (meth)acryloyl group, and an aromatic vinyl group are preferable, one or more selected from the group consisting of a (meth)acryloyl group and an aromatic vinyl group are more preferable, and an aromatic vinyl group is most preferable. That is, in the composition of the present invention, a bifunctional polyphenylene ether in which both ends of the molecular chain are modified with a radically polymerizable functional group is particularly preferable. Examples of such polyphenylene ether include Noryl (trademark) SA9000 of SABIC (modified polyphenylene ether having methacryloyl groups at both ends, number average molecular weight 2200), and bifunctional polyphenylene ether oligomer (OPE-2St) manufactured by Mitsubishi Gas Chemical Company (modified polyphenylene ether having vinylbenzyl groups at both ends, number average molecular weight 1200). Further, allylated PPE of Asahi Kasei Corporation and aromatic polyethers (ELPAC HC-F series and HC-G series) of JSR Corporation can also be used. Among these, preferably, the bifunctional polyphenylene ether oligomer (OPE-2St) manufactured by Mitsubishi Gas Chemical Company and the aromatic polyethers (ELPAC HC-F series and HC-G series) of JSR Corporation can be used.

[0056] [Aromatic polyene resin] The aromatic polyene resin includes a divinylbenzene-based reactive multi-branched copolymer (PDV or ODV) manufactured by Nippon Steel Chemical & Material Co., Ltd. Such a copolymer is described, for example, in the document "Synthesis of multifunctional aromatic vinyl copolymers and development of novel IPN-type low dielectric loss materials using the same" (Shoichiro Kawabe et al., Journal of Electronics Packaging Society, p125, Vol.12, No.2 (2009)).

[0057] [Hardening agent] As the hardening agent that the above composition may contain, known hardening agents that can be used for the polymerization or hardening of conventional aromatic polyenes and aromatic monovinyl compounds may be used. Examples of such hardening agents include radical polymerization initiators, cationic polymerization initiators, and anionic polymerization initiators. Preferably, radical polymerization initiators can be used. Preferably, they are organic peroxide-based (peroxide), azo-based polymerization initiators, etc., and can be freely selected according to the use and conditions. Catalogs listing organic peroxides are available for download from the homepage of NOF Corporation, for example https: / / www.nof.co.jp / product-search / family / 1020001 and can be downloaded from there. Organic peroxides are also described in catalogs of Fuji Film Wako Pure Chemical Corporation, Tokyo Chemical Industry Co., Ltd., etc. The hardening agent used in the present invention can be obtained from these companies. Furthermore, hydrocarbon-based radical polymerization initiators that do not contain oxygen atoms or nitrogen atoms in their structure, that is, radical polymerization initiators composed only of carbon atoms and hydrogen atoms, such as 2,3-dimethyl-2,3-diphenylbutane, can also be preferably used. When a cured body is produced using such a hydrocarbon-based radical polymerization initiator, a cured body with a lower dielectric constant and dielectric tangent that does not contain oxygen atoms or nitrogen atoms can be obtained, and the effect of further improving the low dielectric characteristics of the cured body can be obtained. Also, known photoinitiators using light, ultraviolet rays, or radiation can be used as the hardening agent. Examples of hardening agents using photoinitiators include photo radical polymerization initiators, photo cationic polymerization initiators, or photo anionic polymerization initiators. Such photoinitiators can be obtained, for example, from Tokyo Chemical Industry Co., Ltd. Furthermore, curing by radiation or electron beams themselves is also possible. Also, it is possible to perform crosslinking and curing by thermal polymerization of the raw materials contained without including a hardening agent.

[0058] There is no particular limitation on the amount of the curing agent used, but generally, 0.01 to 10 parts by mass is preferable on an external basis with respect to 100 parts by mass of the composition (preferably excluding the curing agent and the solvent). When using a curing agent such as a peroxide-based (peroxide) or azo-based polymerization initiator, the curing treatment is carried out at an appropriate temperature and time in consideration of its half-life. The conditions in this case are arbitrary according to the curing agent, but generally, a temperature range of about 50°C to 180°C is appropriate.

[0059] [Monomer] The amount of the monomer that the above composition may contain is arbitrary, but preferably 300 parts by mass or less with respect to 100 parts by mass of the above copolymer. When containing a monomer, 1 part by mass or more is preferable, and 5 parts by mass or more is more preferable. In particular, when the monomer is 30 parts by mass or less, the uncured composition is less likely to have a viscous property, and the molding process as a thermoplastic resin becomes easier. Also, when the content of the monomer amount that is likely to volatilize is below a certain level, the odor at the uncured stage does not become a problem. When a solvent is added to the composition to make the product form into a varnish-like state, there is a problem that the monomer is lost along with the evaporation of the solvent during use, and the substantial content of the monomer is likely to decrease. Also, when the product form is an uncured sheet, when the monomer is contained in an amount below a certain level, the change in the monomer content during storage is less likely to occur. The monomer that can be preferably used in the composition of the present invention preferably has a molecular weight of less than 5000, more preferably less than 1000, and even more preferably less than 500. The monomer that can be preferably used in the composition of the present invention is the above-mentioned aromatic monovinyl compound monomer, aromatic polyene monomer, aromatic vinylene monomer, and / or the following polar monomer. As the monomer, a monomer that can be polymerized by a radical polymerization initiator is preferable, and a monomer having the same aromatic vinyl group as the functional group as the copolymer according to the present invention is most preferable. Also, BVPE (1,2-bis(vinylphenyl)ethane) described in JP-A-2003-212941 can also be preferably used.

[0060] [Polar monomer] For the purpose of imparting adhesiveness to other materials required as an insulating material, a polar monomer can be used. Examples of the above-mentioned polar monomers include various maleimides, bismaleimides, maleic anhydride, glycidyl (meth)acrylate, triallyl isocyanurate, tri(meth)acryloyl isocyanurate, trimethylolpropane tri(meth)acrylate, and the like. The maleimides and bismaleimides that can be used in the present invention are described, for example, in International Publication No. 2016 / 114287 or Japanese Patent Application Laid-Open No. 2008-291227, and can be purchased, for example, from Daiwa Kasei Co., Ltd. or Designer molecules inc. As such polar monomers, maleimide resins "MIR-3000" and "MIR-5000" manufactured by Nippon Kayaku Co., Ltd., or bismaleimide-based resins "SLK" manufactured by Shin-Etsu Chemical Co., Ltd. can also be used. These maleimide group-containing compounds may be used as polyaminobismaleimide compounds from the viewpoints of solubility in organic solvents, high-frequency characteristics, high adhesiveness to conductors, moldability of prepregs, and the like. The polyaminobismaleimide compound can be obtained, for example, by subjecting a compound having two maleimide groups at the terminals and an aromatic diamine compound having two primary amino groups in the molecule to a Michael addition reaction. When attempting to obtain high crosslinking efficiency with a small amount of addition, it is preferable to use a polar monomer having a polyfunctional group of two or more functional groups, and examples thereof include bismaleimides, triallyl isocyanurate (TAIC), and trimethylolpropane tri(meth)acrylate. The amount of the polar monomer that the composition may contain is arbitrary, but for example, 0.1 to 30 parts by mass, more preferably 0.1 to 10 parts by mass, is preferable with respect to 100 parts by mass of the copolymer. By using 30 parts by mass or less, the dielectric constant and dielectric tangent of the obtained cured body become low. For example, in a preferred embodiment, the dielectric constant of the cured body of the composition can be suppressed to 3.5 or less, and the dielectric tangent can be suppressed to 1.2×10 -3 It is possible to suppress it below.

[0061] [Flame retardant] As a flame retardant that can be added to the composition, from the viewpoint of maintaining a low dielectric constant and a low dielectric loss tangent, it may be a known organic phosphorus-based material such as a phosphate ester or a condensate thereof, a known bromine-based flame retardant, or red phosphorus. In particular, among phosphate esters, a compound having a plurality of xylyl groups in the molecule is preferable from the viewpoints of flame retardancy and low dielectric loss tangent.

[0062] Furthermore, the flame retardant may include antimony-based compounds such as antimony trioxide, antimony tetroxide, antimony pentoxide, and sodium antimonate as flame retardant aids, or nitrogen-containing compounds such as melamine, triallyl-1,3,5-triazine-2,3,4-(1H,3H,5H)-trione, and 2,4,6-triallyloxy-1,3,5-triazine. The total of these flame retardants and flame retardant aids is usually preferably 1 to 100 parts by mass with respect to 100 parts by mass of the composition. In addition, a resin having a low dielectric constant and excellent flame retardancy based on polyphenylene ether (PPE) may be further added in an amount of 30 to 200 parts by mass with respect to 100 parts by mass of the flame retardant.

[0063] [Surface modifier] The composition may contain various surface modifiers for the purpose of improving the adhesion to organic fillers, copper plates, and wirings. The addition amount of the surface modifier is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, with respect to 100 parts by mass of the present solution. Examples of the surface modifier include various silane coupling agents and titanate-based coupling agents. Various silane coupling agents and titanate-based coupling agents may be used alone or in combination of plural kinds.

Examples

[0064] Hereinafter, the present invention will be described based on further examples and comparative examples, but the scope of the present invention is not limited thereto.

[0065] [Preparation Example 1: St-DVB copolymer (A)] With reference to the description in JP-A-2024-141390, 6.0 mol (781.1 g) of divinylbenzene, 24.0 mol (2499.6 g) of styrene, and 30.0 mol (2764.2 g) of n-propyl acetate were charged into a 10.0 L reactor, and 0.8 mol (113.5 g) of boron trifluoride diethyl ether complex was added at 70°C and reacted for 4 hours. After the polymerization solution was terminated with an aqueous sodium hydrogen carbonate solution, the oil layer was washed 3 times with pure water and devolatilized under reduced pressure at 60°C to recover 821.7 g of the copolymer. The obtained polymer was dissolved in toluene to prepare a 35% by mass solution of the St-DVB copolymer (A).

[0066] The obtained copolymer (A) was analyzed in terms of standard polystyrene conversion by the GPC method under the following conditions, and it was confirmed that Mn was 3460 and Mw was 38900. (The measurement was carried out in the same manner in the following examples.) Column: Two TSK-GEL MultiporeHXL-M φ7.8×300 mm (manufactured by Tosoh Corporation) were connected in series and used. Column temperature: 40°C Solvent: THF Liquid feed flow rate: 1.0 ml / min. Detector: RI detector

[0067] [Preparation Example 2: St-DVB copolymer (B)] With reference to the descriptions in JP-A-2009-161743 and WO 2024 / 190873, 0.1 mol (18.7 g) of divinylbenzene, 1.5 mol (154.0 g) of styrene, and 8.2 mol (719.6 g) of toluene were charged into a 2.0 L reactor, and the mixture was heated and stirred at an internal temperature of 40°C. About 50 L of dry nitrogen gas was bubbled through to purge the moisture in the reactor and the polymerization solution. Next, 1.7 mmol (0.3 g) of triisobutylaluminum in terms of pure triisobutylaluminum was added as a 20 wt% hexane solution of triisobutylaluminum, and immediately ethylene was introduced and stabilized at an internal temperature of 50°C and a pressure of 0.1 MPa. Next, from the catalyst tank installed on the reactor, about 30 mL of a toluene solution in which 0.02 mmol (17.1 mg) of tritium tetrakis(pentafluorophenyl)borate, 0.02 mmol (5.2 mg) of dimethylmethylenebiscyclopentadienylzirconium dichloride, and 0.2 mmol (40.3 g) of triisobutylaluminum in terms of pure triisobutylaluminum were dissolved in a 20 wt% hexane solution of triisobutylaluminum was added to the reactor, and polymerization was carried out for 0.5 hour while maintaining the internal temperature at 65°C and the pressure at 0.1 MPa. The obtained polymerization solution was added little by little to a large amount of vigorously stirred methanol solution to recover the polymer. This polymer was air-dried at room temperature for one day and night and then dried at 80°C in vacuo until no mass change was observed, and 54 g of a copolymer was recovered. The obtained polymer was dissolved in toluene to prepare a 35 mass% solution of the St-DVB copolymer (B). The Mn of the obtained copolymer (B) was 5300 and the Mw was 37200.

[0068] [Preparation Example 3: St-DVB copolymer (C)] Polymerization was carried out in the same manner as in Preparation Example 2 except that toluene in which 0.1 g of polystyrene (SRM705a manufactured by the National Institute of Standards and Technology, USA, Mn = 171000, Mw = 179000) was dissolved in advance was used as the toluene charged into the reactor. The obtained 60 g of polymer was dissolved in toluene to obtain a 35 mass% solution of the St-DVB copolymer (C). The Mn of the obtained copolymer (C) was 5500 and the Mw was 39200.

[0069] [Preparation Example 4: St-DVB copolymer (D)] With reference to the description in JP-A-2006-169381, 0.5 mol (54.1 g) of styrene, 2.6 mol (141.2 g) of 1,3-butadiene, 12.1 mol (1021.8 g) of cyclohexane, and 0.1 mol (10.1 g) of tetrahydrofuran were charged into a 2-L reactor purged with nitrogen. After adjusting the temperature of the reactor contents to 10°C, 2.0 mmol (0.1 g) of a 15 wt% n-hexane solution of n-butyllithium in terms of pure content was added to initiate polymerization. The polymerization was carried out under adiabatic conditions, and the maximum temperature reached 80°C. When the polymerization conversion reached 12%, 0.1 mol (16.1 g) of divinylbenzene was added all at once and reacted for 10 minutes. After stopping the polymerization solution with pure water, the oil layer was washed three times with pure water, and devolatilized under reduced pressure at 60°C to recover 35.6 g of a copolymer. The obtained polymer was dissolved in toluene to prepare a 35 mass% solution of a St-DVB copolymer (D). The Mn of the obtained copolymer (D) was 4120, and the Mw was 37700.

[0070] The composition of the copolymer according to the above Preparation Example was quantified by a known method and summarized in the following table in mol%. In the table, St = styrene, DVB = divinylbenzene, Et = ethylene, and Bd = 1,3-butadiene. [Table 1]

[0071] [Example 1] To 100.0 g of a 35 mass% solution of the above St-DVB copolymer (A), 0.06 g of a toluene solution in which 10 mass% of polystyrene SRM705a (the same as above) was dissolved was added, and then 5.0 g of toluene was added to adjust the solid content to 30 mass%. The obtained 30 mass% solution was evaluated for the haze value measurement, microscopic observation, and stain resistance during the production of a B-stage resin sheet, which will be described later.

[0072] [Measurement of Haze Value] Using the haze meter NDH7000SP2 (manufactured by Nippon Denshoku Industries Co., Ltd.) corresponding to the JIS standard (JIS K7136:2000 and JIS K7361-1:1997), the haze value of a 30% by mass toluene solution of the copolymer was measured.

[0073] [Microscopic Observation] About 1 mL of a 30% by mass toluene solution of the copolymer was taken on a slide glass, spread thinly, and air-dried for 12 hours so that no dust was mixed in. Next, the prepared sample was observed using a ×10 observation lens with a scanning electron microscope (LEXT OLS5100 manufactured by Evident) to confirm the presence or absence of organic filler particles in the range of 5 to 50 μm in diameter.

[0074] [Evaluation of Stain Resistance during Preparation of B-Stage Resin Sheet] 100 g of a 30% by mass toluene solution of the copolymer, 75 g of silica (SFM-130MC manufactured by Denka Co., Ltd.), and 0.5 g of peroxide (Perbutyl P manufactured by NOF Corporation) were placed in a container and stirred well with a stirrer to disperse the silica in the solution. A 7 cm long, 7 cm wide, and 2 mm high silicon frame was placed on a Teflon (registered trademark) sheet, and 2.0 g of the mixed solution was poured into it and dried at 80°C for 12 hours to prepare a 0.2 mm thick B-stage resin sheet. The amount of the mixed solution that oozed out from the silicon frame and became B-staged was determined by measuring the distance from the end of the mixed solution that oozed out from the end of the frame, and evaluated according to the following criteria. 〇(Good): The amount of oozing is less than 2 mm. ×(NG): The amount of oozing is 2 mm or more.

[0075] [Examples 2 to 5] According to the copolymers and addition amounts in the following table, polystyrene was added in the same procedure as in Example 1, and the solid content was adjusted to 30% by mass. For the obtained 30% by mass solution, the haze value was measured, microscopic observation was performed, and the stain resistance during the preparation of the B-stage resin sheet was evaluated in the same manner as in Example 1.

[0076] [Example 6 and Comparative Examples 1 to 3] According to the copolymers and addition amounts in the following table, the solid content was adjusted to 30% by mass. For the obtained 30% by mass solution, the haze value was measured, microscopic observation was carried out, and the anti-bleeding property during the production of the B-stage resin sheet were evaluated in the same manner as in Example 1.

[0077] [Comparative Examples 4 to 6] According to the copolymers and addition amounts in the following table, after adding polystyrene in the same procedure as in Example 1, it was filtered through a cotton filter with a mesh size of 10 μm. Then, toluene was added to the obtained filtered solution to adjust the solid content to 30% by mass. For this 30% by mass solution, the haze value was measured, microscopic observation was carried out, and the anti-bleeding property during the production of the B-stage resin sheet were evaluated in the same manner as in Example 1.

[0078] [Table 2]

[0079] [Table 3]

[0080] As shown in the above results, the presence of the organic filler particles could be confirmed as generally spherical particles in all the examples. Such particles could not be confirmed in the comparative examples. In the examples, the haze value was within a predetermined range, and the anti-bleeding property during lamination was excellent. On the other hand, bleeding outside the allowable range occurred in all the comparative examples.

Claims

1. a copolymer including at least a monomer unit based on styrene and a monomer unit based on divinylbenzene; Organic filler dispersed in a solvent A solution containing The haze value of the solution measured in accordance with JIS K7136:2000 and JIS K 7361-1:1997 is in the range of 8% to 50%. A solution comprising:

2. 2. The solution of claim 1, wherein the organic filler comprises polystyrene.

3. 3. The solution according to claim 1 or 2, wherein the organic filler consists of spherical particles.

4. a copolymer including at least a monomer unit based on styrene and a monomer unit based on divinylbenzene; Solvent and A solution comprising: a part of the copolymer forms crosslinked particles and is dispersed in the solvent; The haze value of the solution measured in accordance with JIS K7136:2000 and JIS K 7361-1:1997 is in the range of 8% to 50%. A solution comprising:

5. 5. The solution of claim 1 or 4, wherein the solvent comprises toluene.

6. 5. The solution according to claim 1, wherein the solution has a solid content concentration in the range of 10% by mass or more and 50% by mass or less.

7. 5. The solution according to claim 1, wherein the copolymer further comprises one or more monomer units based on ethylene or butadiene.

8. A solution according to claim 1 or 4, one or more additive components selected from the group consisting of a resin component, a curing agent, a monomer, a flame retardant, and a surface modifier; A non-liquid composition comprising:

9. 5. A hardened body obtained by substantially removing the solvent from the solution according to claim 1.

10. A cured product of the composition according to claim 8.

11. Preparing a copolymer comprising at least a styrene-based monomer unit and a divinylbenzene-based monomer unit; obtaining a solution containing the copolymer, an organic filler, and a solvent; forming particles made of the organic filler in the solvent, and adjusting the haze value of the solution, measured in accordance with JIS K7136:2000 and JIS K 7361-1:1997, to a range of 8% to 50%; A method for producing a solution comprising the steps of:

12. obtaining the solution, Adding the copolymer and the organic filler to the solvent. The method of claim 11, comprising:

13. The step of preparing the copolymer comprises: A step of forming the styrene-based monomer units and the organic filler based on styrene monomer as a raw material. The method of claim 11, comprising:

14. Preparing a copolymer comprising at least a styrene-based monomer unit and a divinylbenzene-based monomer unit; forming a part of the copolymer into crosslinked particles; adding the crosslinked particles and the remainder of the copolymer to a solvent to adjust the haze value of the solution, measured in accordance with JIS K7136:2000 and JIS K 7361-1:1997, to a range of 8% to 50%; A method for producing a solution comprising the steps of:

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