Thermosetting resin composition, molding material, and sealing material

Abstract

To provide a thermosetting resin composition for sealing electronic components that achieves low environmental impact and maintains excellent curing properties even with the use of a biomass-derived resin.SOLUTION: A thermosetting resin composition comprises an epoxy resin (a2), a furfural-modified phenol resin (b1), and an inorganic filler (c), the furfural-modified phenol resin (b1) being a reaction product of a phenol and biomass-derived furfural.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermosetting resin composition, and a molding material and an encapsulant comprising the thermosetting resin composition. [Background technology]

[0002] Epoxy resin molding materials have traditionally been used as encapsulating materials for electronic components such as coils, capacitors, transistors, ICs, etc. Petroleum-derived epoxy resins, in other words, polymeric materials whose main component is an epoxy resin made from petroleum as a starting material, have generally been used as epoxy resin molding materials. In recent years, with growing calls for the creation of a recycling-oriented society, there has been a growing trend toward using alternative raw materials to petroleum in various applications in consideration of the environment. In the materials field, too, there is a desire to move away from fossil fuels, and the use of biomass has attracted attention. For example, Patent Document 1 describes an epoxidized product of plant-derived lignin and its cured product. However, because lignin extracted from plants is used as is, the epoxidized product of lignin is a compound with a very high molecular weight, which causes problems with workability. In addition, due to its rigid skeleton, it cannot withstand stresses such as heat cycles and drop impacts, particularly when used in adhesives for electrical and electronic components, and therefore has problems such as cracking. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-066237 Summary of the Invention [Problem to be solved by the invention]

[0004] From the viewpoint of utilizing non-fossil resources, it is preferable to use a resin composition having a high biomass content, which is formulated with a resin obtained using a plant-derived raw material, etc. However, compositions containing such biomass-derived resins may be inferior to petroleum-derived resins in physical properties such as fluidity and curing ability, and there is also room for improvement in the electrical reliability and mechanical properties of the resulting cured products.

[0005] The present invention aims to provide a thermosetting resin composition for sealing electronic components, which has a low environmental impact, is comparable in performance to resin compositions made of conventional fossil fuel-derived resins even when using biomass-derived resins, and has excellent curing properties. [Means for solving the problem]

[0006] According to the present invention, there are provided the following thermosetting resin composition, molding material, and encapsulant. [1] epoxy resin (a2), Furfural-modified phenolic resin (b1), and A thermosetting resin composition comprising an inorganic filler (c), The furfural-modified phenolic resin (b1) is a thermosetting resin composition which is a reaction product of a phenol and biomass-derived furfural. [2] The thermosetting resin composition according to [1], A thermosetting resin composition, wherein the inorganic filler (c) is contained in an amount of 70% by mass or more and 95% by mass or less based on the entire thermosetting resin composition. [3] The thermosetting resin composition according to [1] or [2], further comprising a curing accelerator. [4] The thermosetting resin composition according to any one of [1] to [3], wherein the epoxy resin (a2) comprises at least one selected from a novolac type epoxy resin, a trisphenylmethane type epoxy resin, a biphenyl type epoxy resin, and a naphthalene aralkyl type epoxy resin. [5] The thermosetting resin composition according to any one of [1] to [4], further comprising a petroleum-derived phenolic resin (b2). [6] The thermosetting resin composition according to any one of [1] to [5], further comprising a furfural-modified epoxy resin (a1). [7] A molding material comprising the thermosetting resin composition according to any one of [1] to [6]. [8] The molding material according to [7], which is used for transfer molding or compression molding. [9] An encapsulant comprising the thermosetting resin composition according to any one of [1] to [6].

[10] The sealing material according to [9], which is in the form of granules or tablets. [Effects of the Invention]

[0007] According to the present invention, there is provided a thermosetting resin composition which uses a plant-derived resin, reduces the environmental impact, and has performance such as fluidity, curability, and electrical reliability that is comparable to that of sealing materials containing petroleum-derived resins. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing a configuration of a semiconductor device according to an embodiment. [Figure 2] 1 is a cross-sectional view showing a configuration of a semiconductor device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are designated by similar reference numerals, and their description will be omitted where appropriate. Furthermore, all drawings are for illustrative purposes only. The shapes and dimensional ratios of each component in the drawings do not necessarily correspond to actual products. In this specification, the expression "a to b" in the description of a numerical range means "a or more and b or less" unless otherwise specified. For example, "5 to 90%" means "5% or more and 90% or less."

[0010] [Thermosetting resin composition] The thermosetting resin composition according to this embodiment comprises an epoxy resin (a2), a furfural-modified phenolic resin (b1), and an inorganic filler (c), wherein the furfural-modified phenolic resin (b1) is a reaction product of phenols and biomass-derived furfural. Each component used in the thermosetting resin composition according to this embodiment will be described below.

[0011] (Epoxy resin (a2)) The epoxy resin (a2) used in the thermosetting resin composition of this embodiment is a petroleum-derived epoxy resin. Examples of petroleum-derived epoxy resins include bifunctional or crystalline epoxy resins such as biphenyl-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, stilbene-type epoxy resins, and hydroquinone-type epoxy resins; novolac-type epoxy resins such as cresol novolac-type epoxy resins, phenol novolac-type epoxy resins, and naphthol novolac-type epoxy resins; phenol aralkyl-type epoxy resins such as phenylene-skeleton-containing phenol aralkyl-type epoxy resins, biphenylene-skeleton-containing phenol aralkyl-type epoxy resins, and phenylene-skeleton-containing naphthol aralkyl-type epoxy resins; trifunctional epoxy resins such as triphenolmethane-type epoxy resins and alkyl-modified triphenolmethane-type epoxy resins; modified phenol-type epoxy resins such as dicyclopentadiene-modified phenol-type epoxy resins and terpene-modified phenol-type epoxy resins; and heterocycle-containing epoxy resins such as triazine-nucleus-containing epoxy resins. These may be used alone or in combination of two or more.

[0012] The content of the epoxy resin (a2) in the thermosetting resin composition of this embodiment is, from the viewpoint of improving the fluidity of the thermosetting resin composition and improving workability and moldability, for example, 3 mass% or more, preferably 8 mass% or more, more preferably 10 mass% or more, and even more preferably 12 mass% or more, based on the total solid content of the resin composition. Furthermore, from the viewpoint of improving the strength and heat resistance of a cured product formed using the thermosetting resin composition, the content of the epoxy resin (a2) is preferably 30 mass% or less, more preferably 20 mass% or less, based on the total solid content of the thermosetting resin composition.

[0013] (Furfural-modified phenolic resin (b1)) The furfural-modified phenolic resin (b1) used in the thermosetting resin composition of this embodiment is a phenolic resin obtained by reacting phenols with biomass-derived furfural. The structure and physical properties of the furfural-modified phenolic resin (b1) used in this embodiment can be adjusted to a desired level by appropriately selecting the type and amount of catalyst, type and amount of solvent, reaction temperature, reaction time, and other combinations used in the reaction of phenols with furfural.

[0014] More specifically, the furfural-modified phenolic resin (b1) used in this embodiment can be obtained by reacting a phenol with furfural.

[0015] Here, when producing a novolac-type furfural-modified phenolic resin (b1), the novolac-type furfural-modified phenolic resin (b1) can be obtained by condensation polymerization of phenols and furfural in the presence of an acid catalyst (step 1a). When producing the resol-type furfural-modified phenolic resin (b1), a phenol and furfural are condensation-polymerized in the presence of a basic catalyst to obtain the resol-type furfural-modified phenolic resin (b1) (step 1b).

[0016] Examples of phenols that can be used to produce the furfural-modified phenolic resin (b1) include phenol; cresols such as o-cresol, m-cresol, and p-cresol; ethylphenols such as o-ethylphenol, m-ethylphenol, and p-ethylphenol; butylphenols such as isopropylphenol, butylphenol, and p-tert-butylphenol; alkylphenols such as p-tert-amylphenol, p-octylphenol, p-nonylphenol, and p-cumylphenol; halogenated phenols such as fluorophenol, chlorophenol, bromophenol, and iodophenol; substituted monohydric phenols such as p-phenylphenol, aminophenol, nitrophenol, dinitrophenol, and trinitrophenol; monohydric phenols such as 1-naphthol and 2-naphthol; and polyhydric phenols such as resorcinol, alkylresorcinol, pyrogallol, catechol, alkylcatechol, hydroquinone, alkylhydroquinone, phloroglucinol, bisphenol A, bisphenol F, bisphenol S, and dihydroxynaphthalene. These may be used alone or in combination of two or more. Among these, phenol is preferably used from the viewpoint of production costs.

[0017] The furfural used in the production of the furfural-modified phenolic resin (b1) is derived from biomass, for example, furfural produced from agricultural by-products such as corn cobs, oat husks, sugarcane pomace, bran, and sawdust.

[0018] Examples of the acid catalyst used in the step (step 1a) of obtaining a novolak-type furfural-modified phenolic resin (b1) by condensation polymerization of a phenol and furfural in the presence of an acid catalyst include organic acids such as acetic acid, formic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, benzoic acid, salicylic acid, sulfonic acid, phenolsulfonic acid, and paratoluenesulfonic acid; and inorganic acids such as hydrochloric acid, sulfuric acid, sulfate esters, phosphoric acid, and sulfate esters.

[0019] Examples of basic catalysts used in the step (step 1b) of obtaining a resol-type furfural-modified phenolic resin (b1) by condensation polymerization of phenols and furfural in the presence of a basic catalyst include hydroxides of alkali metals or alkaline earth metals such as sodium hydroxide, potassium hydroxide, calcium hydroxide, etc.; carbonates such as sodium carbonate and calcium carbonate; oxides such as lime; sulfites such as sodium sulfite; phosphates such as sodium phosphate; amines such as ammonia, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, hexamethylenetetramine, and pyridine.

[0020] In the reaction of phenols with furfural in step 1a or 1b, the molar ratio of furfural to phenols (F / P) is, for example, 0.5 or more, preferably 0.55 or more, and more preferably 0.6 or more. The upper limit of the molar ratio of furfural to phenols (F / P) is, for example, 1.2 or less, preferably 1.1 or less, and more preferably 1.0 or less. By carrying out the reaction under conditions where the molar ratio of furfural to phenols (F / P) is within the above range, a furfural-modified phenolic resin (b1) having a desired weight-average molecular weight can be obtained.

[0021] In step 1a, the reaction of phenols with furfural in the presence of an acidic catalyst is preferably carried out at a temperature of, for example, 60 to 120°C, preferably 80 to 100°C, for a reaction time of, for example, 10 to 100 minutes, which allows the reaction to proceed efficiently and sufficiently. In step 1b, the reaction of phenols with furfural in the presence of a basic catalyst is preferably carried out at a temperature of, for example, 60 to 120°C, preferably 80 to 100°C, for a reaction time of, for example, 10 to 100 minutes, which allows the reaction to proceed efficiently and sufficiently. In step 1a or step 1b, the amount of the catalyst used is, for example, in the range of 0.005 to 2.0 mol, and preferably in the range of 0.01 to 1.1 mol, relative to 1 mol of the phenol. By carrying out the above step 1a or step 1b under heating, the starting materials are uniformly mixed, and the molecular weight of the resulting furfural-modified phenolic resin (b1) can be made uniform due to intermolecular entanglement and intermolecular action. The reaction time is not particularly limited and may be appropriately determined depending on the type of starting materials, the blending molar ratio, the amount and type of catalyst used, and the reaction conditions.

[0022] The reaction solvent used for producing the novolac-type furfural-modified phenolic resin (b1) in step 1a or step 1b is generally water, but organic solvents may also be used. Specific examples of such organic solvents include alcohols, ketones, aromatic compounds, etc. Specific examples of alcohols include methanol, ethanol, propyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, glycerin, etc. Specific examples of ketones include acetone and methyl ethyl ketone. Specific examples of aromatic compounds include toluene and xylene.

[0023] After the reaction is complete, the by-product salt is removed by filtration, washing with water, etc., and the solvent, such as toluene, xylene, or methyl isobutyl ketone, is distilled off under heating and reduced pressure to obtain a furfural-modified phenolic resin (b1) with a low content of hydrolyzable halogen.

[0024] The biomass degree (%) of the furfural-modified phenolic resin (b1) is, for example, 1 to 100%, preferably 10 to 80%, and more preferably 20 to 60%. The biomass degree of fossil-derived epoxy resins is 0%. The biomass degree is 14The C concentration can be measured by measuring the radiocarbon concentration. In the present invention, the radiocarbon concentration is measured by accelerator mass spectrometry (AMS). Accelerator mass spectrometry is a method for measuring the carbon isotopes ( 12 C. 13 C. 14 C) is physically separated using an accelerator, taking advantage of the difference in atomic weight, and the abundance of isotope atoms is measured.

[0025] The content of the furfural-modified phenolic resin (b1) in the thermosetting resin composition of this embodiment is, for example, 0.53% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on the total solid content of the resin composition, from the viewpoints of improving the flowability, workability, and moldability of the thermosetting resin composition while ensuring that the resulting thermosetting resin composition has a high biomass content. Furthermore, from the viewpoint of improving the strength and heat resistance of a cured product formed using the thermosetting resin composition, the content of the furfural-modified phenolic resin (b1) is preferably 20% by mass or less, more preferably 15% by mass or less, based on the total solid content of the thermosetting resin composition.

[0026] From the viewpoint of improving the moldability and reliability of the resulting thermosetting resin composition, the furfural-modified phenolic resin (b1) is blended so that the equivalent ratio of the epoxy resin (a2) to the phenolic resin (b1), i.e., the ratio of (the number of moles of epoxy groups in the epoxy resin / the number of moles of phenolic hydroxyl groups in the phenolic resin-based curing agent), is preferably 0.5 or more, more preferably 0.6 or more, and even more preferably 0.8 or more. From the same viewpoint, the ratio is preferably 2 or less, more preferably 1.8 or less, and even more preferably 1.5 or less.

[0027] (Inorganic filler (c)) Examples of the inorganic filler (c) used in the thermosetting resin composition of this embodiment include fused silica such as fused crushed silica and fused spherical silica, silica such as crystalline silica, alumina, aluminum hydroxide, silicon nitride, and aluminum nitride. These may be used alone or in combination of two or more. From the viewpoint of improving the mechanical properties or thermal properties of the cured resin composition, the inorganic filler preferably contains silica, and more preferably contains one or more selected from the group consisting of crushed silica and fused spherical silica.

[0028] The inorganic filler (c) has an average particle size d50 of preferably 0.01 μm or more, more preferably 1 μm or more, and even more preferably 5 μm or more, from the viewpoints of improving the fluidity and moldability of the resulting thermosetting resin composition. The inorganic filler has an average particle size d50 of preferably 50 μm or less, more preferably 40 μm or less, from the viewpoints of improving filling properties and suppressing the occurrence of unfilled portions.

[0029] The content of the inorganic filler (c) in the thermosetting resin composition is preferably 70% by mass or more, more preferably 75% by mass or more, based on the total amount of the resin composition, from the viewpoints of suppressing the moisture absorption and thermal expansion of the thermosetting resin composition and more effectively improving the temperature cycle resistance and moisture resistance of the cured product of the resin composition. Furthermore, from the viewpoint of more effectively improving the fluidity and filling ability of the thermosetting resin composition during molding, the content of the inorganic filler (c) is preferably 95% by mass or less, more preferably 93% by mass or less, based on the total amount of the resin composition.

[0030] When the inorganic filler (c) contains silica, the content of silica in the thermosetting resin composition is preferably 50% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 80% by mass or more, based on the total amount of the resin composition, from the viewpoint of suppressing the moisture absorption and thermal expansion of the resin composition and more effectively improving the temperature cycle resistance and moisture resistance of the cured product of the resin composition. Also, from the viewpoint of more effectively improving the fluidity and filling property of the resin composition during molding, the content of silica in the resin composition is preferably 95% by mass or less, more preferably 93% by mass or less.

[0031] (Petroleum-derived phenolic resin (b2)) In one embodiment, the thermosetting resin composition of the present invention may contain a petroleum-derived phenolic resin (b2) in addition to the furfural-modified phenolic resin (b1). Examples of the petroleum-derived epoxy resin (b2) include novolac resins obtained by condensing or co-condensing phenols, such as phenol novolac resins and cresol novolac resins, with formaldehyde or ketones under an acidic catalyst; biphenyl-type phenolic resins having a phenylene skeleton synthesized from the above-mentioned phenols with dimethoxy-paraxylene or bis(methoxymethyl)biphenyl; phenol aralkyl resins, such as phenol aralkyl resins having a biphenylene skeleton; and phenolic resins having a trisphenylmethane skeleton. These may be used alone or in combination of two or more.

[0032] The content of the phenolic resin (b2) in the thermosetting resin composition of the present embodiment is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, based on the total amount of the thermosetting resin composition, from the viewpoint of realizing excellent fluidity and improving filling properties and moldability in the encapsulation step. On the other hand, from the viewpoint of improving the moisture resistance reliability and heat resistance of the cured resin product, the content of the phenolic resin (b2) is preferably 20 mass % or less, more preferably 15 mass % or less, even more preferably 10 mass % or less, and particularly preferably 5 mass % or less, based on the total amount of the thermosetting resin composition.

[0033] (Furfural-modified epoxy resin (a1)) In one embodiment, the thermosetting resin composition of the present invention may contain a furfural-modified epoxy resin (a1) in addition to the petroleum-derived epoxy resin (a2). The furfural-modified epoxy resin (a1) may be an epoxy resin obtained by glycidyl etherifying the phenolic hydroxyl groups of a phenolic resin, which is a reaction product of phenols and biomass-derived furfural. The combined use of the furfural-modified phenolic resin (b1) and the furfural-modified epoxy resin (a1) can improve the biomass content of the resulting resin composition.

[0034] When the furfural-modified epoxy resin (a1) is used, its content is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, based on the total amount of the thermosetting resin composition, from the viewpoint of realizing excellent fluidity and improving filling properties in the encapsulation step. In order to obtain performance comparable to that of a resin composition made of a fossil-derived resin, the content of the furfural-modified epoxy resin (a1) is, for example, 10 mass % or less based on the total amount of the thermosetting resin composition.

[0035] The furfural-modified epoxy resin (a1) can be obtained by reacting a phenol with furfural to obtain a phenolic resin (step 1), and glycidyl etherifying the phenolic hydroxyl groups of the furfural-modified phenolic resin (b1) obtained in step 1 (step 2).

[0036] The step (step 1) of reacting a phenol with furfural to obtain a phenolic resin can be achieved by the same production method as that for the furfural-modified phenolic resin (b1). In step 2 following step 1, the phenolic hydroxyl groups of the furfural-modified phenolic resin (b1) obtained in step 1 are glycidyl-etherified using a conventionally known method to obtain the target furfural-modified epoxy resin (a1). Examples of epihalohydrins used in the glycidyl-etherification reaction of the furfural-modified phenolic resin (b1) include epichlorohydrin, epibromohydrin, epiiodohydrin, β-methylepichlorohydrin, β-methylepibromohydrin, and β-ethylepichlorohydrin, with epichlorohydrin being preferred because it is industrially readily available and inexpensive.

[0037] The glycidyl etherification reaction is carried out, for example, by reacting a mixture of the furfural-modified phenolic resin (b1) obtained in step 1 and epihalohydrins at 20 to 120°C for 1 to 20 hours while adding, all at once or gradually, a solid alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. In this case, an aqueous solution of the alkali metal hydroxide may be used, and in this case, the alkali metal hydroxide may be continuously added while continuously distilling water and epihalohydrins from the reaction system under reduced pressure or normal pressure, followed by liquid separation to remove water and continuously return the epihalohydrins to the reaction system.

[0038] In the above method, the amount of epihalohydrins used is, for example, 0.5 to 20 mol, preferably 0.7 to 10 mol, relative to 1 equivalent of the hydroxyl groups in the furfural-modified phenolic resin (b1). The amount of alkali metal hydroxide used is, for example, 0.5 to 1.5 mol, preferably 0.7 to 1.2 mol, relative to 1 equivalent of the hydroxyl groups in the furfural-modified phenolic resin (b1). Furthermore, by adding an aprotic polar solvent such as dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, or 1,3-dimethyl-2-imidazolidinone to the above reaction, an epoxy resin with a low concentration of hydrolyzable halogen can be obtained, making it suitable for use as an encapsulant for electronic materials. The amount of the aprotic polar solvent used is usually 5 to 200 wt %, preferably 10 to 100 wt %, relative to the weight of the epihalohydrins. In addition to the above solvents, the addition of alcohols such as methanol or ethanol can also facilitate the reaction. Toluene, xylene, dioxane, etc. can also be used.

[0039] Typically, after washing with water, or without washing with water, the reaction product is heated under reduced pressure to remove excess epihalohydrins, and then dissolved in a solvent such as toluene, xylene, or methyl isobutyl ketone. An aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added, and the reaction is carried out again. In this case, the amount of alkali metal hydroxide used is typically 0.01 to 0.2 mol, preferably 0.05 to 0.1 mol, per equivalent of the hydroxyl groups in the furfural-modified phenolic resin (b1). The reaction temperature is typically 50 to 120°C, and the reaction time is typically 0.5 to 2 hours.

[0040] After the reaction is complete, the by-product salt is removed by filtration, washing with water, etc., and the solvent, such as toluene, xylene, or methyl isobutyl ketone, is distilled off under heating and reduced pressure to obtain a furfural-modified phenolic resin (b1) with a low content of hydrolyzable halogen.

[0041] The synthesis step of the furfural-modified phenolic resin (b1) and the glycidyl etherification step can also be carried out consecutively. For example, after reacting phenols with furfural in the method of step 1, epihalohydrins can be added directly to the system without removing unreacted raw materials and solvents by distillation under heating and reduced pressure, and glycidyl etherification can be carried out in accordance with the above-mentioned method. In the final solvent distillation step, the glycidyl etherified product of the unreacted raw materials (phenols) can be distilled off together with the solvent to obtain the desired furfural-modified epoxy resin (a1).

[0042] The furfural-modified epoxy resin (a1) has a biomass ratio (%) of, for example, 1 to 100%, preferably 10 to 80%, and more preferably 20 to 60%. The biomass ratio of fossil-derived epoxy resins is 0%.

[0043] (Other ingredients) The thermosetting resin composition of the present embodiment may contain components other than the above-mentioned components. For example, various additives such as a curing accelerator, a coupling agent, a flame retardant, an ion scavenger, a colorant, and an antioxidant may be appropriately blended.

[0044] (curing accelerator) The curing accelerator may be any accelerator that accelerates the crosslinking reaction between the epoxy resin and the curing agent, and any accelerator that is used in general epoxy resin compositions may be used. Specific examples of curing accelerators include diazabicycloalkenes and their derivatives, such as 1,8-diazabicyclo(5,4,0)undecene-7; organic phosphines, such as triphenylphosphine and methyldiphenylphosphine; imidazole compounds (imidazole-based curing accelerators), such as 2-methylimidazole; and tetra-substituted phosphonium tetra-substituted borates, such as tetraphenylphosphonium tetraphenylborate.

[0045] Examples of the imidazole curing accelerator include imidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, and 1-cyanoethyl-2-phenylimidazole. Examples of suitable compounds include imidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4-methylimidazolyl(1')]-ethyl-s-triazine, an isocyanuric acid adduct of 2,4-diamino-6-[2'-methylimidazolyl(1')]-ethyl-s-triazine, an isocyanuric acid adduct of 2-phenylimidazole, an isocyanuric acid adduct of 2-methylimidazole, 2-phenyl-4,5-dihydroxydimethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole.

[0046] (coupling agent) As the coupling agent, for example, various silane-based compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, vinylsilane, and methacrylsilane, titanium-based compounds, aluminum chelates, and aluminum / zirconium-based compounds can be used. Examples of these include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-anilinopropyltrimethoxysilane, γ-anilinopropylmethyldimethoxysilane, γ-[bis(β-hydroxyethyl)]aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyl N-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, phenylaminopropyltrimethoxysilane, γ-(β-aminoethyl)aminopropyldimethoxymethylsilane, N-(trimethoxysilylpropyl)ethylenediamine, N-(dimethoxymethylsilylisopropyl)ethylenediamine, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, vinyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-triethoxysilyl-N-(1,Silane coupling agents such as hydrolyzed 3-dimethyl-butylidene)propylamine, isopropyl triisostearoyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, bis(dioctyl pyrophosphate)oxyacetate titanate Examples of titanate coupling agents include titanate, bis(dioctyl pyrophosphate)ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, and tetraisopropyl bis(dioctyl phosphite) titanate. These may be used alone or in combination of two or more. Among these, silane compounds such as epoxy silane, mercapto silane, amino silane, alkyl silane, ureido silane, or vinyl silane are more preferred. Furthermore, from the viewpoint of more effectively improving filling properties and moldability, it is even more preferred to use secondary amino silanes, such as phenylaminopropyl trimethoxy silane.

[0047] When a coupling agent is used, the content thereof is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, based on the total solid content of the resin composition, from the viewpoint of obtaining favorable fluidity of the resin composition. Furthermore, from the viewpoint of improving the mechanical strength of the cured product of the resin composition, the content of the coupling agent is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less, based on the total solid content of the resin composition.

[0048] (coloring agent) Examples of colorants include carbon black, red iron oxide, titanium oxide, etc. Among these, carbon black is preferably used as the colorant. The content of the colorant is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, based on the total amount of the resin composition, from the viewpoint of obtaining a desirable appearance of the cured product of the resin composition. Also, from the viewpoint of obtaining a desirable resin viscosity, the content of the colorant is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less, based on the total amount of the resin composition.

[0049] (antioxidant) Examples of the antioxidant include hindered phenol compounds, hindered amine compounds, and thioether compounds.

[0050] [Method for producing thermosetting resin composition] The thermosetting resin composition of this embodiment can be produced by uniformly mixing the above components and optional additives to a predetermined content using a mixer or blender such as a tumbler mixer or Henschel mixer, and then kneading the mixture while heating using a kneader, roll, disperser, azimuth homomixer, planetary mixer, or the like. The kneading temperature must be within a range in which a curing reaction does not occur, and although this varies depending on the composition of the epoxy resin and curing agent, melt-kneading at approximately 70 to 150°C is preferred. After kneading, the mixture may be cooled and solidified, and the kneaded mixture may be processed into powder, granules, tablets, or sheets.

[0051] A method for obtaining a powdery resin composition includes, for example, pulverizing the kneaded material using a pulverizer. The kneaded material may be formed into a sheet and then pulverized. Examples of the pulverizer that can be used include a hammer mill, a stone mill, and a roll crusher.

[0052] As a method for obtaining a granular or powdery resin composition, for example, a granulation method represented by a hot-cut method can be used, in which a die having a small diameter is provided at the outlet of a kneading device and the molten kneaded material discharged from the die is cut to a predetermined length with a cutter, etc. In this case, after obtaining a granular or powdery resin composition by a granulation method such as the hot-cut method, it is preferable to degas the resin composition before the temperature of the resin composition drops significantly.

[0053] [Physical properties of thermosetting resin composition] The thermosetting resin composition of this embodiment has excellent fluidity and therefore good moldability. The fluidity of the thermosetting resin composition can be evaluated using spiral flow as an index. The thermosetting resin composition of this embodiment has a spiral flow length measured under the following conditions of 100 cm or more and 250 cm or less, preferably 100 cm or more and 220 cm or less, more preferably 120 cm or more and 200 cm or less, and even more preferably 155 cm or more and 180 cm or less. (conditions) The flow length measured by injecting the thermosetting resin composition into a spiral flow measurement mold conforming to EMMI-1-66 under conditions of a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a curing time of 120 seconds is taken as the spiral flow length.

[0054] The thermosetting resin composition of this embodiment has excellent curability, and the gel time at 175°C is 10 to 60 seconds, preferably 20 to 50 seconds, and more preferably 32 to 45 seconds. This allows the thermosetting resin composition to have excellent filling properties, and prevents the occurrence of unfilled portions. The gel time can be measured by melting the resin composition on a hot plate heated to 175°C, and then kneading it with a spatula while measuring the time it takes for the composition to become tack-free (gel time).

[0055] [Physical properties of the cured product] By curing the thermosetting resin composition of this embodiment, it is possible to obtain an environmentally friendly cured product obtained from plant-derived raw materials, and the biomass content of the cured product can be set to 5% or more and 95% or less.

[0056] When the thermosetting resin composition of this embodiment is cured at 175° C. for 2 minutes, the cured product can have a flexural strength of 80 MPa or more, preferably 100 MPa or more, and more preferably 110 MPa or more at room temperature of 25° C. The upper limit is not particularly limited, but is preferably 300 MPa or less.

[0057] When the thermosetting resin composition of this embodiment is cured at 175° C. for 2 minutes, the cured product can have a flexural modulus of 10,000 MPa or more, preferably 12,000 MPa or more, and more preferably 13,000 MPa or more at room temperature of 25° C. The upper limit is not particularly limited, but is preferably 30,000 MPa or less. The thermosetting resin composition of the present embodiment can provide a cured product having excellent mechanical strength because the cured product obtained from the composition has a bending strength or bending modulus within the above range. In this embodiment, the above properties can be controlled by appropriately selecting, for example, the type and amount of each component contained in the thermosetting resin composition, the method for preparing the thermosetting resin composition, and the like.

[0058] [Application] The thermosetting resin composition of the present embodiment can be used as a sealing material for various electronic components, such as a circuit board on which electronic components are mounted, a rotor core to which a magnet is fixed (see International Publication WO2012 / 029278, etc.), a stator core to which a coil or the like is insulated (see Japanese Patent Application Laid-Open No. 2020-094092, etc.), an in-vehicle electronic control unit (see International Publication WO2016 / 139985, etc.), a semiconductor device, etc.

[0059] The rotor core will now be described. A permanent magnet is inserted into a hole provided in the rotor core, and a resin composition is filled between the hole and the permanent magnet, thereby fixing the permanent magnet to the rotor core. The tablet obtained by the method of the present invention can be used in this resin composition filling process. Using the tablet of the present invention as an encapsulant makes it possible to increase the size of rotor cores and produce multiple cores simultaneously.

[0060] The stator core will now be described. The stator core has multiple teeth, and coils are wound around the multiple teeth. At this time, the coils need to be insulated from the stator core, and this can be achieved by interposing an encapsulating resin composition. The resin composition of the present invention can be applied in the process of interposing this resin composition. Using the tablet of the present invention as an encapsulant makes it possible to increase the size of stator cores and produce multiple cores simultaneously.

[0061] An in-vehicle electronic control unit will be described. A substrate on which electronic components and the like are mounted is being considered as an in-vehicle electronic control unit, and is sealed with a resin composition. The resin composition of the present invention can be applied in the process of sealing with this resin composition. By using the tablet of the present invention as a sealant, it becomes possible to increase the size of in-vehicle electronic control units and simultaneously produce multiple units.

[0062] A semiconductor device will now be described. The semiconductor device is one in which a semiconductor element is encapsulated with a cured product of the thermosetting resin composition of the present embodiment described above. Specific examples of the semiconductor element include integrated circuits, large-scale integrated circuits, transistors, thyristors, diodes, solid-state imaging elements, etc. The semiconductor element is preferably an element that does not involve light input or output, excluding optical semiconductor elements such as light-receiving elements and light-emitting elements (e.g., light-emitting diodes).

[0063] The substrate of the semiconductor device is, for example, a wiring board such as an interposer or a lead frame, and the semiconductor element is electrically connected to the substrate by wire bonding, flip-chip connection, or the like.

[0064] Examples of semiconductor devices obtained by encapsulating a semiconductor element using a thermosetting resin composition through encapsulation molding include MAP (Mold Array Package), QFP (Quad Flat Package), SOP (Small Outline Package), CSP (Chip Size Package), QFN (Quad Flat Non-leaded Package), SON (Small Outline Non-leaded Package), BGA (Ball Grid Array), LF-BGA (Lead Flame BGA), FCBGA (Flip Chip BGA), MAPBGA (Molded Array Process BGA), eWLB (Embedded Wafer-Level BGA), Fan-In type eWLB, and Fan-Out type eWLB. The following will explain this in more detail with reference to the drawings.

[0065] 1 and 2 are cross-sectional views showing the configuration of a semiconductor device, but in this embodiment, the configuration of the semiconductor device is not limited to those shown in FIGS. First, the semiconductor device 100 shown in FIG. 1 includes a semiconductor element 20 mounted on a substrate 30, and a sealing material 50 that seals the semiconductor element 20. The sealing material 50 is made of a cured product obtained by curing the thermosetting resin composition of the present embodiment described above.

[0066] 1 also illustrates an example in which the substrate 30 is a circuit board. In this case, as shown in FIG. 1, a plurality of solder balls 60, for example, are formed on the other surface of the substrate 30 opposite to the surface on which the semiconductor element 20 is mounted. The semiconductor element 20 is mounted on the substrate 30 and electrically connected to the substrate 30 via wires 40. Alternatively, the semiconductor element 20 may be flip-chip mounted on the substrate 30. Here, the wires 40 are not limited to, but examples thereof include Ag wires, Ni wires, Cu wires, Au wires, and Al wires. Preferably, the wires 40 are made of Ag, Ni, or Cu, or an alloy containing one or more of these.

[0067] The sealing material 50 seals the semiconductor element 20, for example, by covering the other surface of the semiconductor element 20 opposite to the surface facing the substrate 30. In the example shown in FIG. 1 , the sealing material 50 is formed to cover the other surface and the side surface of the semiconductor element 20.

[0068] In this embodiment, the encapsulant 50 is made of a cured product of the above-described thermosetting resin composition. Therefore, in the semiconductor device 100, the encapsulant 50 and the wires 40 have excellent adhesion, which makes the semiconductor device 100 highly reliable. The sealing material 50 can be formed by sealing and molding a thermosetting resin composition using a known method such as transfer molding or compression molding.

[0069] 2 is a cross-sectional view showing the configuration of a semiconductor device 100 according to this embodiment, illustrating an example different from that shown in FIG. 2. The semiconductor device 100 shown in FIG. 2 uses a lead frame as the substrate 30. In this case, the semiconductor element 20 is mounted on, for example, a die pad 32 of the substrate 30, and is electrically connected to outer leads 34 via wires 40. The encapsulant 50 is made of a cured product of the thermosetting resin composition according to this embodiment, similar to the example shown in FIG. 1.

[0070] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted as long as they do not impair the effects of the present invention. [Example]

[0071] EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these.

[0072] (Synthesis Example 1: Synthesis of furfural-modified phenolic resin (B1)) A flask equipped with a stirrer, reflux condenser, and stirring device was charged with 188 parts by weight of phenol, 20 parts by weight of water, and 9.9 parts by weight of sodium hydroxide. After stirring and dissolving, the mixture was heated to 110°C, and 50 parts by weight of furfural was added dropwise over 1 hour. The mixture was then reacted at 120°C for 4 hours while removing water, and then heated to 145°C while removing water. After reaching 145°C, 50 parts by weight of water was gradually added, and the mixture was neutralized with 36% hydrochloric acid. Next, 300 parts by weight of methyl isobutyl ketone was added, and the mixture was washed with water several times. Unreacted phenol was removed from the oil layer under heating and reduced pressure, yielding 90 parts by weight of furfural-modified phenolic resin (B1).

[0073] (Synthesis Example 2: Synthesis of furfural-modified epoxy resin (A1)) 145 parts by weight of the furfural-modified phenolic resin (b1) obtained in Synthesis Example 1, 500 parts by weight of epichlorohydrin (ECH, hereinafter the same), and 150 parts by weight of dimethyl sulfoxide (DMSO, hereinafter the same) were charged into a reaction vessel, heated, stirred, and dissolved. After that, the temperature was maintained at 45°C and the reaction system was maintained at 45 Torr. 100 parts by weight of 40 wt% aqueous sodium hydroxide solution was continuously added dropwise over 4 hours. The ECH and water distilled azeotropically during this process were cooled and separated, and the organic layer, ECH, was returned to the reaction system for further reaction. After the addition of the aqueous sodium hydroxide solution was completed, the reaction was continued for another 3 hours at 45°C and then for 1 hour at 70°C. The mixture was then repeatedly washed with water to remove by-product salts and dimethyl sulfoxide. After that, excess epichlorohydrin was removed from the oil layer under reduced pressure and heating, and 500 parts by weight of methyl isobutyl ketone was added to the residue and dissolved. This methyl isobutyl ketone solution was heated to 70°C, 10 parts by weight of 30% aqueous sodium hydroxide solution was added, and the reaction mixture was allowed to react for 1 hour. The reaction mixture was then repeatedly washed with water until the washings became neutral. Then, methyl isobutyl ketone was distilled off from the oil layer under heating and reduced pressure to obtain 190 parts by weight of furfural-modified epoxy resin (A1).

[0074] [Example 1, Comparative Example 1] A mixture was obtained by mixing the components shown in Table 1 in the ratios shown in the table. The mixing was carried out at room temperature using a Henschel mixer. Thereafter, the mixture was roll-kneaded at 70 to 100° C. to obtain a kneaded product. The obtained kneaded product was cooled and then pulverized to obtain a resin composition. The components listed in Table 1 are as follows:

[0075] (inorganic filler) Inorganic filler 1: Fused spherical silica (manufactured by Denka, FB-950, average particle size 24 μm) Inorganic filler 2: Fused spherical silica (Admatechs, SO-C2, average particle size 0.5 μm) Inorganic filler 3: Fused crushed silica (manufactured by Admatechs, SO-C5, average particle size 1.5 μm) (coloring agent) Colorant 1: Carbon black (Mitsubishi Chemical Corporation, Carbon #5) (coupling agent) Coupling agent 1: N-phenyl-3-aminopropyltrimethoxysilane (CF-4083, manufactured by Toray Dow Corning Co., Ltd.) (epoxy resin) Epoxy resin 1: Orthocresol novolac epoxy resin (Chang Chun Plastics Co., Ltd., CNE-195LL) Epoxy resin 2: Furfural-modified epoxy resin (A1) prepared in Synthesis Example 2 above

[0076] (phenolic resin) Phenolic resin 1: Novolac phenolic resin (Sumitomo Bakelite Co., Ltd., PR-HF-3) Phenolic resin 2: Furfural-modified phenolic resin (B1) prepared in Synthesis Example 1 above (curing accelerator) Curing accelerator 1: Triphenylphosphine (mold release agent) Release agent 1: Oxidized polyethylene wax (Clariant Japan, Licowax PED191) (ion scavenger) Ion scavenger 1: Magnesium aluminum hydroxide carbonate hydrate (Kyowa Chemical Industry Co., Ltd., DHT-4H) (low stress agent) Low-stress agent 1: Epoxy polyether modified silicone oil (Dow Corning Toray, FZ-3730)

[0077] The resin compositions obtained in the examples were subjected to the following measurements. The measurement results are shown in Table 1.

[0078] (Biomass ratio) The biomass content of the resin composition obtained in each example was determined by the radioactive carbon ( 14 C) The concentration ratio of carbon circulating in nature as of 1950 was measured using an accelerator mass spectrometer (NEC, "Pelletron AMS"). 14The C concentration was used as the standard (100%).

[0079] (Spiral Flow) Spiral flow measurements were performed on the resin compositions obtained in each example. Spiral flow measurements were performed using a low-pressure transfer molding machine (Kotaki Seiki Co., Ltd., "KTS-15") by injecting the resin composition into a spiral flow measurement mold conforming to EMMI-1-66 under conditions of a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a cure time of 120 seconds, and measuring the flow length (cm). Spiral flow is an index of fluidity, with a higher value indicating better fluidity.

[0080] (Gel time) The gel time of the resin composition obtained in each example was measured by melting the resin composition on a hot plate heated to 175°C, and then measuring the time (gel time: seconds) until the resin composition hardened while being kneaded with a spatula.

[0081] (glass transition temperature, linear expansion coefficient) For each example, the glass transition temperature and linear expansion coefficient of the cured resin composition were measured as follows. First, the resin composition was injected into a transfer molding machine at a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a curing time of 3 minutes to obtain 15 mm x 4 mm x 4 mm test pieces. The test pieces were then post-cured at 175°C for 4 hours and then measured using a thermomechanical analyzer (Seiko Instruments Inc., TMA100) at a temperature range of 0°C to 320°C and a heating rate of 5°C / min. From the measurement results, the glass transition temperature, the linear expansion coefficient below the glass transition temperature (CTE1), and the linear expansion coefficient above the glass transition temperature (CTE2) were calculated. In the table, the units of CTE1 and CTE2 are ppm / K. The results are shown in the table.

[0082] (Flexural strength and flexural modulus) For each example, the resulting resin composition was tableted to obtain tablets. The resulting tablets were then injection molded using a transfer molding machine under conditions of a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a curing time of 120 seconds to obtain cured products measuring 10 mm wide, 4 mm thick, and 80 mm long. The resulting test pieces were then post-cured at 175°C for 4 hours to obtain test pieces for evaluation. The flexural strength and flexural modulus of the obtained test pieces were measured in accordance with JIS K 6911 at room temperature (25°C) and 260°C.

[0083] (specific gravity) The specific gravity of the resin composition obtained in each example was measured by the underwater displacement method (Archimedes' method).

[0084] (Mold shrinkage rate) The molding shrinkage of the cured resin composition obtained in each example was measured as follows. -ASM (Adjusted Shrinkage Rate) Using a low-pressure transfer molding machine (KTS-30, manufactured by Kotaki Seiki Co., Ltd.), the resin composition of each example was injection molded under conditions of a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a curing time of 120 seconds to obtain molded articles with a diameter of 90 mm and a thickness of 5 mm. Next, the mold shrinkage of the obtained test pieces was measured using a method in accordance with JIS K6911. The mold shrinkage is expressed in %. -Molding shrinkage rate (PMC) Using a low-pressure transfer molding machine (KTS-30, manufactured by Kotaki Seiki Co., Ltd.), the resin composition of each example was injected and molded under conditions of a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a cure time of 120 seconds, yielding molded articles measuring 90 mm in diameter and 5 mm in thickness. The molded articles were then post-cured at 175°C for 4 hours to yield test specimens made of the cured product of each resin composition. The mold shrinkage of the test specimens was then measured using a method in accordance with JIS K6911. The mold shrinkage is expressed in %.

[0085] (Water absorption rate) The resin composition of each example was heated at 175°C for 4 hours, and the resulting cured product was dried at 150°C for 16 hours. The mass of the cured product at this stage was recorded as the mass before moisture absorption treatment. Subsequently, moisture absorption treatment was performed for 24 hours under conditions of a temperature of 125°C, a pressure of 0.2 MPa, and a relative humidity of 100% RH. The weight of the cured product at this stage was recorded as the weight after moisture absorption treatment. The water absorption rate was calculated using the following formula. Formula: (Water absorption rate) = {(mass after moisture absorption treatment - mass before moisture absorption treatment) / mass before moisture absorption treatment} x 100 (%)

[0086] [Table 1] [Explanation of symbols]

[0087] 20 Semiconductor elements 30 boards 32 die pad 34 outer lead 40 wire 50 Encapsulating material 60 solder balls 100 Semiconductor device

Claims

1. Epoxy resin (a2), Furfural-modified phenolic resin (b1), and A thermosetting resin composition comprising an inorganic filler (c), The furfural-modified phenolic resin (b1) is a thermosetting resin composition which is a reaction product of a phenol and furfural derived from biomass.

2. The thermosetting resin composition according to claim 1, The thermosetting resin composition, wherein the inorganic filler (c) is contained in an amount of 70% by mass or more and 95% by mass or less based on the entire thermosetting resin composition.

3. The thermosetting resin composition of claim 1 , further comprising a curing accelerator.

4. 2. The thermosetting resin composition according to claim 1, wherein the epoxy resin (a2) comprises at least one selected from a novolac type epoxy resin, a trisphenylmethane type epoxy resin, a biphenyl type epoxy resin, and a naphthalene aralkyl type epoxy resin.

5. The thermosetting resin composition according to claim 1, further comprising a petroleum-derived phenolic resin (b2).

6. The thermosetting resin composition according to claim 1 , further comprising a furfural-modified epoxy resin (a1).

7. A molding material comprising the thermosetting resin composition according to any one of claims 1 to 6.

8. The molding material according to claim 7, which is used in transfer molding or compression molding.

9. An encapsulant comprising the thermosetting resin composition according to any one of claims 1 to 6.

10. The sealing material according to claim 9, which is in the form of granules or tablets.

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