Biomass epoxy resin composition

Abstract

The biomass epoxy resin composition comprises an epoxy resin, a biomass-derived curing agent, a biomass-derived monomer, and a polymerization initiator, and is characterized in that the gelation time of the polymer of the monomers at 100 DEG C or lower is within 20 minutes, and the glass transition temperature of the polymer of the monomers is 60 DEG C or higher.

Description

Technical Field

[0001] The present disclosure relates to biomass epoxy resin compositions. Background Art

[0002] Epoxy resins are widely used as insulating materials for electrical equipment due to their excellent thermomechanical properties, electrical properties, moisture resistance, chemical resistance, dimensional stability, etc. Once cured, epoxy resins react in a three-dimensional network to form a strong cured product. They are a type of thermosetting resin that is insoluble and infusible, and it is considered difficult to reuse them after curing. Therefore, a large amount of used epoxy resins are disposed of by incineration, landfill, etc., but when epoxy resins are incinerated, CO2, a greenhouse gas, is generated.

[0003] In recent years, from the perspective of preventing global warming, the reduction of CO2 emissions has become a topic. In addition, the use of petroleum resources is also required to be thrifty, and materials with low environmental load are required. Considering this background, it is proposed to use biomass materials with carbon neutrality as raw materials for epoxy resins.

[0004] In Japanese Patent Publication No. 2009-263549 (Patent Document 1) and Japanese Patent Publication No. 2013-181040 (Patent Document 2), an epoxy resin composition composed of a curing agent from biomass that is solid at room temperature is disclosed. In Patent Document 1, a method of using lignin having a phenolic skeleton in the molecule as a curing agent is proposed, and it is disclosed that: an epoxy resin cured product having a high glass transition temperature (Tg) of more than 200°C is obtained. In addition, in Patent Document 2, from the viewpoint of moldability, a method of using a derivative of a polyphenol from a plant with a relatively low molecular weight as a curing agent is proposed.

[0005] In addition, Japanese Patent Application Publication No. 2016-520677 (Patent Document 3) discloses a multi-component synthetic resin adhesive containing at least one of a reactive diluent and a reactive resin (including an epoxy resin). Patent Document 3 lists increasing the proportion of bio-derived materials in the synthetic resin adhesive and improving product characteristics related to environmental performance and sustainability as issues, and proposes a method for solving the above issues by using a bio-derived reactive diluent and a reactive resin.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2009-263549

[0009] Patent Document 2: Japanese Patent Application Publication No. 2013-181040

[0010] Patent Document 3: Japanese Patent Application No. 2016-520677 Summary of the invention

[0011] Problems to be solved by the invention

[0012] However, in patent documents 1 and 2, both use a solidifying agent of room temperature solid, which has a problem of poor workability compared to the resin combination using a liquid solidifying agent. Especially, as disclosed in patent document 1, when using lignin with a large molecular weight as a solidifying agent, the viscosity of the resin combination improves and workability decreases. In addition, as disclosed in patent document 2, when using pyrogallol as a derivative of polyphenols as a solidifying agent, although compared with lignin, the improvement of workability is expected, there is room for improvement in heat resistance.

[0013] In addition, although a reactive diluent derived from biomass is used as a constituent component in Patent Document 3, no research has been conducted on workability and heat resistance. In particular, regarding heat resistance, it is known that the structure of a cured product composed of a multi-component synthetic resin has an influence, and control of the structure of the cured product becomes important.

[0014] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a biomass epoxy resin composition that is excellent in environmental friendliness and has both workability and heat resistance.

[0015] Means for solving problems

[0016] The present inventors have conducted intensive studies to solve the above problems and have found that a combination of an epoxy resin, a biomass-derived curing agent, a biomass-derived monomer, and a polymerization initiator can provide an effect of achieving excellent environmental friendliness and achieving both workability and heat resistance.

[0017] The present disclosure relates to the following biomass epoxy resin composition.

[0018] A biomass epoxy resin composition comprises an epoxy resin, a curing agent derived from biomass, a monomer derived from biomass, and a polymerization initiator, wherein the gelation time of the polymer of the above monomers at 100° C. or below is within 20 minutes, and the glass transition temperature of the polymer of the above monomers is above 60° C.

[0019] Effects of the Invention

[0020] According to the present disclosure, it is possible to provide a biomass epoxy resin composition that is excellent in environmental friendliness and has both workability and heat resistance. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments of the present disclosure will be described.

[0022] Implementation method 1.

[0023] <Biomass epoxy resin composition>

[0024] The biomass epoxy resin composition of the present embodiment includes an epoxy resin (A), a biomass-derived curing agent (B), a biomass-derived monomer (C), and a polymerization initiator (D). The gel time of the polymer of the biomass-derived monomer (C) at 100°C or less is within 20 minutes. The Tg of the polymer of the biomass-derived monomer (C) is 60°C or more. It should be noted that the polymer of the biomass-derived monomer (C) is also referred to as a "polymer" hereinafter.

[0025] (Epoxy resin (A))

[0026] The epoxy resin (A) contained in the biomass epoxy resin composition of the present embodiment is a compound having two or more oxirane rings (epoxy groups) per molecule. The shape of the epoxy resin (A) is not particularly limited, but from the viewpoint of dissolving the solid biomass-derived curing agent (B), the epoxy resin (A) is preferably liquid at room temperature.

[0027] As such epoxy resin (A), for example, bisphenol A epoxy resin, bisphenol F epoxy resin, cresol novolac epoxy resin, alicyclic epoxy resin, glycidylamine epoxy resin, etc. can be cited. Among these epoxy resins (A), bisphenol A epoxy resin and bisphenol F epoxy resin are preferred from the viewpoint of workability and heat resistance. In addition, when high heat resistance is required, multifunctional epoxy resin is preferred.

[0028] The epoxy resin (A) may be derived from petroleum or biomass. In addition, the epoxy resin (A) may be used alone or in combination of two or more. When two or more are used in combination, the combination is not particularly limited.

[0029] (Solidifying agent (B) derived from biomass)

[0030] The biomass epoxy resin composition of the present embodiment contains a biomass-derived curing agent (B). By containing a biomass-derived curing agent (B), a biomass epoxy resin composition having excellent environmental properties can be obtained.

[0031] As for the curing agent (B) from biomass, from the viewpoint of heat resistance, it is preferably a compound with an aromatic ring. As such a curing agent (B) from biomass, for example, aromatic compounds such as 4-aminobenzoic acid, 4-hydroxybenzoic acid, protocatechuic acid, and industrial lignin obtained by isolating lignin as a phenolic macromolecular compound using various methods, etc. can be listed. Among these curing agents (B) from biomass, 4-aminobenzoic acid, 4-hydroxybenzoic acid, and protocatechuic acid are preferred. This is because: 4-aminobenzoic acid, 4-hydroxybenzoic acid, and protocatechuic acid are low molecular weights. By using a low molecular weight curing agent (B) from biomass, the mixed viscosity of the biomass epoxy resin composition is suppressed to be low, and a biomass epoxy resin composition with excellent workability can be obtained.

[0032] The biomass-derived curing agent (B) may be used alone or in combination of two or more. The biomass-derived curing agent (B) may be derived entirely from biomass or partially from biomass.

[0033] The content of the biomass-derived curing agent (B) is such that the equivalent ratio of the functional group in the biomass-derived curing agent (B) molecule to the epoxy group in the epoxy resin (A) molecule is 0.3 to 3.0 when the epoxy group in the epoxy resin (A) molecule and the functional group that can react with the active hydrogen of the amino group, hydroxyl group, carboxyl group, acid anhydride, etc. in the biomass-derived curing agent (B) molecule react at a chemical equivalent of 1:1. If the equivalent ratio is outside the above range, the heat resistance and other characteristics may not be fully exhibited.

[0034] In addition, the content of the biomass-derived curing agent (B) is preferably such that the number of active hydrogens of the epoxy group in the epoxy resin (A) and the functional group in the biomass-derived curing agent (B) are equivalent. For example, when a bisphenol A-type epoxy resin having an epoxy equivalent of 190 g / eq is used as the epoxy resin (A) and 4-aminobenzoic acid is used as the biomass-derived curing agent (B), the amount of 4-aminobenzoic acid is 24.0 parts by weight relative to 100 parts by weight of the bisphenol A-type epoxy resin. For example, when the same bisphenol A-type epoxy resin is used as the epoxy resin (A) and 4-hydroxybenzoic acid is used as the biomass-derived curing agent (B), the amount of 4-hydroxybenzoic acid is 36.4 parts by weight relative to 100 parts by weight of the bisphenol A-type epoxy resin.

[0035] (Monomers (C) from biomass)

[0036] The biomass epoxy resin composition of the present embodiment contains a biomass-derived monomer (C). By containing a biomass-derived monomer (C), a biomass epoxy resin composition having excellent environmental properties and workability can be obtained.

[0037] As the monomer (C) derived from biomass, for example, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, tetrabutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, neopentyl glycol dimethacrylate, etc. can be cited. The monomer (C) derived from biomass can be used alone or in combination of two or more. In addition, the monomer (C) derived from biomass can be completely derived from biomass or partially derived from biomass. It should be noted that as long as the monomer (C) derived from biomass is included, the monomer from petroleum can also be included.

[0038] Among these monomers (C) derived from biomass, ethyl methacrylate, tetrabutyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, isobornyl (meth)acrylate, etc. are preferred, and isobornyl (meth)acrylate is more preferred. This is because isobornyl (meth)acrylate has a high Tg (Tg: 180°C), and isobornyl (meth)acrylate is compatible with epoxy resin (A), thereby obtaining a biomass epoxy resin composition having excellent heat resistance. Therefore, the biomass epoxy resin composition using isobornyl (meth)acrylate can be suitably used for applications requiring high heat resistance.

[0039] It should be noted that, as described later, when the biomass epoxy resin composition of the present embodiment is made into a cured product, the Tg of the polymer is 60° C. or higher. The above-mentioned biomass-derived monomer (C) also includes a biomass-derived monomer having a Tg of less than 60° C., and the Tg of the polymer can be adjusted to be 60° C. or higher by combining two or more of a biomass-derived monomer (C) having a Tg of 60° C. or higher and a biomass-derived monomer (C) having a Tg of less than 60° C.

[0040] The content of the monomer (C) derived from biomass is 10 to 70% by weight relative to the epoxy resin (A), the curing agent (B) derived from biomass, and the monomer (C) derived from biomass. When the content of the monomer (C) derived from biomass is less than 10% by weight, the effect of the monomer (C) derived from biomass may be reduced. When the content of the monomer (C) derived from biomass exceeds 70% by weight, the biomass epoxy resin composition becomes brittle and may impair moldability.

[0041] (Polymerization initiator (D))

[0042] The biomass epoxy resin composition of this embodiment includes a polymerization initiator (D). The polymerization initiator (D) is a compound that can initiate the polymerization of the monomer (C) from biomass, and includes free radical initiators that generate active free radicals, acids, etc. by the action of light or heat, and redox initiators that generate free radicals by redox reactions.

[0043] As the polymerization initiator (D), for example, organic peroxides such as hydroperoxides, dialkyl peroxides, peroxyesters, diacyl peroxides, peroxycarbonates, peroxyketals, ketone peroxides, and combinations of these organic peroxides with reducing agents such as metal salts and amines, etc., can be cited. Among these polymerization initiators (D), combinations of hydroperoxides and metal salts, and combinations of ketone peroxides and metal salts that can efficiently generate free radicals even at low temperatures are preferred. As hydroperoxides, for example, tert-butyl hydroperoxide, cumene hydroperoxide, etc. can be cited. As ketone peroxides, for example, methyl ethyl ketone peroxide, cyclohexanone peroxide, etc. can be cited. As metal salts, for example, cobalt salts such as cobalt naphthenate and cobalt octoate, vanadium compounds such as vanadium pentoxide, etc. can be cited.

[0044] The content of the polymerization initiator (D) depends on the type of the biomass-derived monomer (C) used, and is 0.001 to 20 parts by weight, preferably 0.005 to 10 parts by weight, relative to 100 parts by weight of the biomass-derived monomer (C). By making the content of the polymerization initiator (D) within the above range, the gel time of the polymer described later can be adjusted to an appropriate range.

[0045] (Curing accelerator)

[0046] In the case of the biomass epoxy resin composition of the present embodiment, a curing accelerator may be included in order to increase the curing speed of the epoxy resin (A). As a curing accelerator, there is no particular limitation as long as the curing of the epoxy resin (A) is promoted. For example, tertiary amine accelerators such as benzyldimethylamine, imidazole accelerators such as 2-ethyl-4-methylimidazole, phosphorus accelerators such as triphenylphosphine, organic metals such as zinc octanoate, etc. can be listed. The curing accelerator can be used alone or in combination of two or more. The content of the curing accelerator can be appropriately adjusted according to the type of epoxy resin (A) and curing agent (B) used, and is generally 0.1 to 100 parts by weight relative to 100 parts by weight of the epoxy resin (A).

[0047] (Properties of biomass epoxy resin composition)

[0048] [Gel time]

[0049] With regard to the biomass epoxy resin composition of the present embodiment, when a cured product is made, the gel time of the polymer at 100°C or below is within 20 minutes. This is because, when the gel time of the polymer at 100°C or below exceeds 20 minutes, as the monomer (C) from biomass volatilizes, the reaction of the epoxy resin (A) and the curing agent (B) from biomass proceeds, and the viscosity increases, so the degree of polymerization of the monomer (C) from biomass is suppressed, and it becomes difficult to obtain the effect of adding the monomer (C) from biomass. The gel time of the polymer at 100°C or below is preferably within 18 minutes. It should be noted that the faster the gel time, the better. From the perspective of the moldability of the biomass epoxy resin composition, it is preferably 30 seconds or more.

[0050] The gel time can be measured, for example, by the following procedure. As a measuring device, for example, a gel tester (No. 153 gel time tester manufactured by Yasuda Seiki Co., Ltd.) is prepared. The rotor is rotated in a test tube containing 1 ml of a sample composed of a polymer. When the gelation of the sample progresses and a certain torque is applied to the rotor, the rotor falls due to the magnetic coupling mechanism and the timer stops. The time at this time is set as the gel time.

[0051] [Glass transition temperature]

[0052] In the biomass epoxy resin composition of the present embodiment, when a cured product is prepared, the Tg of the polymer is 60° C. or higher. When the Tg of the polymer is less than 60° C., the heat resistance is reduced. The Tg of the polymer is preferably 100° C. or higher. It is preferred that the Tg is higher, and for example, it may be 300° C. or lower.

[0053] Tg can be measured, for example, by the following steps. As a measuring device, for example, a dynamic viscoelasticity measuring (DMA) device (DMS6100 manufactured by Hitachi High-Tech Co., Ltd.) is prepared. A test piece (40 mm long × 10 mm wide × 1 to 3 mm thick) composed of a polymer is used for measurement under the following test conditions, and the peak temperature of the loss tangent (tan δ) is set to Tg.

[0054] {Test conditions}

[0055] Deformation mode: Stretch mode

[0056] Measuring temperature: 25~250℃

[0057] Heating rate: 2℃ / min

[0058] Frequency: 0.2~5Hz

[0059] [Phase structure]

[0060] In the present embodiment, the phase structure of the cured product of the biomass epoxy resin composition (hereinafter referred to as "phase structure") affects the physical properties such as heat resistance and mechanical strength. As for the phase structure, examples include the cured product of the epoxy resin (A) and the curing agent (B) from the biomass, that is, the epoxy resin cured product and the polymer are incompatible and separated, that is, the phase separation state, the epoxy resin cured product and the polymer are compatible, etc. As for the phase structure, it can be determined by the peak shape and peak temperature of tanδ of the dynamic viscoelasticity of the cured product.

[0061] When the Tg of the epoxy resin cured product (hereinafter also referred to as Tg1) and the Tg of the polymer (hereinafter also referred to as Tg2) are different, if they are completely phase-separated from each other, two tan δ peaks will appear as the Tgs shown by each.

[0062] In addition, if the epoxy resin cured material is compatible with the polymer, a single tanδ peak appears. In the case where the epoxy resin cured material is compatible with the polymer, there are examples of (1) a state in which the epoxy resin cured material and the polymer have functional groups that can chemically bond to each other; (2) a state in which the epoxy resin cured material and the polymer each form a network structure but do not have functional groups that chemically bond to each other; (3) a state in which one of the epoxy resin cured material and the polymer forms a network structure and the other is a long-chain polymer that does not form a network structure and does not have functional groups that chemically bond to each other. In (1), the mutual network structures or the network structure and the chain structure form a single network structure through chemical bonds, so the peak of tanδ is one. In (2), when the mutual network structures form a physically intertwined inter-invading network (IPN) structure, the peak of tanδ is one. In (3), the long-chain polymer forms a physically intertwined semi-IPN structure with another network structure, so the peak of tanδ is one.

[0063] Furthermore, sometimes the peak of tanδ appears as two peaks or shoulders at values ​​different from the Tg shown by each single body of the epoxy resin cured product and the polymer. In this case, there can be listed (1) a state in which the epoxy resin cured product and the polymer have functional groups that can chemically bond with each other; (2) a state in which the epoxy resin cured product and the polymer form an IPN structure in which the mutual network structures are uniformly physically entangled; (3) a state in which a long-chain polymer forms a semi-IPN structure physically entangled with another network structure. In (1), the compatibility of the epoxy resin cured product and the polymer is improved by chemical bonds, and in the case of a small number of functional groups and a high molecular weight of the polymer, partial or whole phase separation occurs. In (2), if there is a part with weak entanglement, the polymer phase separates. In (3), similarly to (2), if there is a part with weak entanglement of the molecular chain, the polymer phase separates partially or entirely.

[0064] In this embodiment, when Tg2 is lower than Tg1, the epoxy resin cured product and the polymer phase in the biomass epoxy resin composition are preferably separated. In this case, since Tg1 shows the same Tg as the single epoxy resin (A), it is possible to prevent the reduction of the overall Tg of the biomass epoxy resin composition.

[0065] On the other hand, when Tg2 is higher than Tg1, the epoxy resin cured product and the polymer in the biomass epoxy resin composition are preferably completely compatible or partially compatible. In this case, Tg1 can be increased compared to the Tg of the epoxy resin (A) alone, and can be suitably used for applications requiring higher heat resistance.

[0066] (Radiocarbon)

[0067] The biomass epoxy resin composition of the present embodiment contains radioactive carbon (carbon 14, hereinafter referred to as "C14"). C14 always exists in a certain proportion in the atmosphere. During the growth process, plants absorb CO2 in the atmosphere, so the C14 contained in the plants also becomes the same proportion as that in the atmosphere. On the other hand, fossil resources such as petroleum do not contain C14, and can be distinguished into carbon from biomass and carbon from petroleum. The current concentration of C14 in the atmosphere is about 100pMC (percent Modern Carbon). If a certain biomass plastic is made of 100% of substances from biomass, the pMC of its sample is about 100. On the other hand, in the case of substances from petroleum, the pMC of the sample is approximately 0. For example, in the case of a sample in which the mixing ratio (based on the amount of carbon) of the substance from biomass and the substance from petroleum is 50% on average, a value of about 50pMC is expressed. Therefore, by calculating the ratio of C14 in the biomass epoxy resin composition, the load of the biomass epoxy resin composition on the environment can be verified.

[0068] The content of C14 relative to the total carbon in the biomass epoxy resin composition of the present embodiment is 20% or more. The content of C14 is calculated by the following formula (1).

[0069] Content of C14 in the biomass epoxy resin composition (%) = 100 × C14 content in the biomass epoxy resin composition / total carbon content in the biomass epoxy resin composition (1)

[0070] When the content of C14 in the biomass epoxy resin composition is less than 20%, the effect as a carbon offset material is insufficient.

[0071] (mixed viscosity)

[0072] From the viewpoint of workability, the mixed viscosity of the biomass epoxy resin composition is preferably 5000 mPa·s or less at 60°C, more preferably 1000 mPa·s or less, and further preferably 300 mPa·s or less. In this embodiment, an E-type viscometer is used to measure the mixed viscosity of the biomass epoxy resin composition. It is noted that the mixed viscosity is preferably small, for example, 10 mPa·s or more.

[0073] (use)

[0074] The biomass epoxy resin composition of this embodiment is not particularly limited in its use and can be used in various applications. For example, it can be dissolved in an organic solvent and used as a varnish for a motor, or it can be added with a filler and used as a molding resin for a motor, a power module, etc., as in Embodiment 2 described later.

[0075] <Method for producing biomass epoxy resin composition>

[0076] There is no particular limitation on the method for producing the biomass epoxy resin composition of the present embodiment. For example, an epoxy resin (A) and a curing agent (B) derived from biomass are mixed at room temperature or heated to obtain a first mixture. The heating temperature is, for example, in the range of 40 to 180°C. A monomer (C) and a polymerization initiator (D) derived from biomass are mixed at room temperature to obtain a second mixture. The biomass epoxy resin composition is obtained by heating and mixing these first and second mixtures. The heating temperature and heating time can be appropriately set according to the epoxy resin (A), the curing agent (B) derived from biomass, and the monomer (C) derived from biomass used. The heating temperature is, for example, in the range of 40 to 180°C, and from the viewpoint of suppressing the volatilization of the monomer (C) derived from biomass, it is preferably in the range of 40 to 120°C. The heating time is, for example, in the range of 1 to 180 minutes. The degree of polymerization of the biomass-derived monomer (C) varies depending on the heating temperature and heating time. For example, heating at a high temperature for a short time and heating at a low temperature for a long time may result in the same degree of polymerization.

[0077] When the epoxy resin (A) and the biomass-derived curing agent (B) are mixed, a solvent may be used. The solvent is not particularly limited, and examples thereof include toluene and methyl ethyl ketone.

[0078] In addition, for example, after the epoxy resin (A), the biomass-derived curing agent (B) and the biomass-derived monomer (C) are mixed at room temperature or under heating, a polymerization initiator (D) is added, and the mixture is mixed at room temperature or under heating. The heating temperature when the epoxy resin (A), the biomass-derived curing agent (B) and the biomass-derived monomer (C) are mixed is, for example, in the range of 40 to 180° C. The heating temperature after the addition of the polymerization initiator (D) is, for example, in the range of 40 to 180° C.

[0079] The curing conditions of the biomass epoxy resin composition are not particularly limited. For example, the heating temperature is in the range of 30 to 300° C., and the heating time is in the range of 1 minute to 100 hours.

[0080] Implementation method 2.

[0081] The biomass epoxy resin composition involved in this embodiment further includes an inorganic filler (E). By including an inorganic filler (E) in the biomass epoxy resin composition, a biomass epoxy resin composition having a desired mechanical strength and linear expansion coefficient can be obtained. It is explained that the description other than the aspects different from the first embodiment is omitted.

[0082] (Inorganic filler (E))

[0083] As inorganic filler (E), it is not particularly limited, for example, metal oxide particles such as aluminum oxide (alumina), zinc oxide, indium tin oxide (ITO), magnesium oxide, beryllium oxide, titanium oxide, metal nitride particles such as boron nitride, silicon nitride, aluminum nitride, silicon carbide, graphite, diamond, amorphous carbon, carbon black, carbon fiber, silicon dioxide compound powders such as quartz, quartz glass, etc. can be listed. These can be used alone, or two or more combinations can be used. Among these, from the viewpoint of insulation, preferably aluminum oxide (alumina), zinc oxide, magnesium oxide, beryllium oxide, titanium oxide, boron nitride, silicon nitride, aluminum nitride, diamond, quartz, quartz glass, etc.

[0084] The average particle size of the inorganic filler (E) is preferably 1 nm to 100 μm, more preferably 1 nm to 80 μm. When the average particle size of the inorganic filler (E) is less than 1 nm, the viscosity of the biomass epoxy resin composition increases, which may impair workability and moldability. When the average particle size of the inorganic filler (E) exceeds 100 μm, the strength of the cured product of the biomass epoxy resin composition is likely to decrease, and the inorganic filler (E) is likely to settle during the storage of the biomass epoxy resin composition.

[0085] With regard to the content of inorganic filler (E), it is preferably 40 to 90% by weight, more preferably 70 to 85% by weight relative to the entire biomass epoxy resin composition. When the content of inorganic filler (E) is less than 40% by weight, it is possible that a cured product of the biomass epoxy resin composition having the required mechanical strength and thermal expansion coefficient cannot be obtained. When the content of inorganic filler (E) exceeds 90% by weight, the viscosity of the biomass epoxy resin composition increases, which may impair workability and moldability.

[0086] (Coupling agent)

[0087] With the improvement of wettability of inorganic filler (E) and biomass epoxy resin composition, the reinforcement of the interface of inorganic filler (E) and biomass epoxy resin composition, the improvement of dispersibility of inorganic filler (E) etc. as the purpose, inorganic filler (E) can be implemented to be coupled with a coupling agent. As such a coupling agent, for example, γ-glycidyloxypropyl trimethoxysilane, N-β (aminoethyl) γ-aminopropyl triethoxysilane, N-phenyl-γ-aminopropyl trimethoxysilane, γ-mercaptopropyl trimethoxysilane etc. can be listed. These can be used alone, and two or more kinds can also be used in combination.

[0088] The content of the coupling agent can be appropriately set depending on the types of the epoxy resin (A) and the inorganic filler (E), and is, for example, 0.01 to 5 parts by weight based on 100 parts by weight of the epoxy resin (A).

[0089] (Manufacturing method)

[0090] The method for mixing the inorganic filler (E) is not particularly limited. For example, the epoxy resin (A) and the biomass-derived curing agent (B) may be mixed at room temperature or under heating, and the inorganic filler (E) may be mixed in the step of obtaining the first mixture. For example, the inorganic filler (E) may be mixed in the step of heating and mixing the first mixture and the second mixture.

[0091] Furthermore, for example, the inorganic filler (E) may be mixed in the step of mixing the epoxy resin (A), the biomass-derived curing agent (B), and the biomass-derived monomer (C) at room temperature or under heating.

[0092] The coupling treatment of the inorganic filler (E) using a coupling agent can be carried out by a conventionally known method before mixing the inorganic filler (E).

[0093] Implementation method 3.

[0094] The biomass epoxy resin composition involved in the present embodiment also includes a compatible monomer (F). By including a compatible monomer (F) in the biomass epoxy resin composition, the epoxy resin cured material and the polymer partially form a chemical bond, and the compatibility of the epoxy resin cured material and the polymer is improved. As a result, a biomass epoxy resin composition with improved heat resistance can be obtained. It is explained that the description other than the aspects different from the first embodiment is omitted.

[0095] (Compatible monomer (F))

[0096] The compatible monomer (F) is preferably a monomer having at least one functional group selected from a first functional group reactive with the epoxy resin (A) and the biomass-derived monomer (C) and a second functional group reactive with the biomass-derived curing agent (B) and the biomass-derived monomer (C).

[0097] Examples of the compatible monomer (F) having a first functional group include acrylates such as methacrylamide, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxyphenyl (meth)acrylate, 4-vinylphenol, and β-carboxyethyl acrylate, methacrylates, and styrenes such as p-acetoxystyrene, o-acetoxystyrene, m-acetoxystyrene, 3-methoxy-4-acetoxystyrene and p-hydroxyphenylstyrene.

[0098] Examples of the compatible monomer (F) having a second functional group include glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, (meth)allyl glycidyl ether, (meth)allyl methyl glycidyl ether, 3,4-epoxycyclohexylmethyl (meth)acrylate, and 4-hydroxybutyl acrylate glycidyl ether.

[0099] These may be used alone or in combination of two or more. Among these, glycidyl methacrylate is preferred from the viewpoint of compatibility.

[0100] The content of the compatible monomer (F) can be appropriately adjusted according to the types of the epoxy resin (A), biomass-derived curing agent (B), and biomass-derived monomer (C) used. In addition, the content of the epoxy resin (A) or the biomass-derived curing agent (B) can be adjusted according to the content of the compatible monomer (F).

[0101] The content of the compatible monomer (F) is, for example, such that the epoxy group in the molecule of the epoxy resin (A) and the functional group that can react with the active hydrogen of the amino group, hydroxyl group, carboxyl group, acetoxy group, acid anhydride, etc. in the molecule of the compatible monomer (F) react at a chemical equivalent of 1:1, and the equivalent ratio of the functional group in the molecule of the compatible monomer (F) to the epoxy group in the molecule of the epoxy resin (A) is 0.3 to 3.0. When the equivalent ratio is outside the above range, the characteristics such as heat resistance may not be fully manifested.

[0102] The content of the compatible monomer (F) may be, for example, such that the functional group capable of reacting with the epoxy group in the molecule of the biomass-derived curing agent (B) reacts with the epoxy group in the molecule of the compatible monomer (F) at a chemical equivalent of 1:1, and the equivalent ratio of the functional group in the molecule of the biomass-derived curing agent (B) to the epoxy group in the molecule of the compatible monomer (F) is 0.3 to 3.0. If the equivalent ratio is outside the above range, properties such as heat resistance may not be fully exhibited.

[0103] (Manufacturing method)

[0104] There is no particular limitation on the method for mixing the compatible monomer (F). For example, the biomass-derived monomer (C) and the polymerization initiator (D) may be mixed at room temperature, and the compatible monomer (F) may be mixed in the step of obtaining the second mixture. For example, the compatible monomer (F) may be mixed in the step of heating and mixing the first mixture and the second mixture.

[0105] Furthermore, for example, the compatible monomer (F) may be mixed in the step of mixing the epoxy resin (A), the biomass-derived curing agent (B), and the biomass-derived monomer (C) at room temperature or under heating.

[0106] Example

[0107] Hereinafter, the present disclosure will be described in detail with reference to Examples, but the present disclosure is not limited to these.

[0108] <Example 1>

[0109] Prepare the components (A) to (D) in the amounts shown in Table 1. Heat and mix the components (A-1) and (B-1) at 130°C to obtain a first mixture. After uniformly mixing the components (C-1) and (D-1) at room temperature, add the component (D-2) and uniformly mix them to obtain a second mixture. The obtained first mixture and the second mixture are mixed and heated at 100°C for 15 minutes to obtain the biomass epoxy resin composition of Example 1. In addition, the obtained biomass epoxy resin composition is heated at 80°C for 2 hours, at 130°C for 2 hours, and at 180°C for 2 hours to obtain a cured product of the biomass epoxy resin composition.

[0110] <Examples 2 to 4>

[0111] A biomass epoxy resin composition and a cured product thereof were obtained in the same manner as in Example 1 except that the blending amounts of the components (C) and (D) were changed to the amounts shown in Table 1.

[0112] <Example 5>

[0113] A biomass epoxy resin composition and a cured product thereof were obtained in the same manner as in Example 1 except that the amount of component (D) was changed to the amount shown in Table 1 and the heating time after mixing the first mixture and the second mixture was changed to 5 minutes.

[0114] <Example 6>

[0115] A biomass epoxy resin composition and a cured product thereof were obtained by the same method as in Example 1, except that component (B-1) was replaced by component (B-2), component (C-1) was replaced by component (C-2), and the blending amounts of each component (B) to (D) were changed to the amounts shown in Table 1.

[0116] <Example 7>

[0117] Prepare the components (A) to (E) in the amounts shown in Table 1. Heat the components (A-1) and (B-1) at 130°C and mix them to obtain a first mixture. Heat the component (C-1) at 100°C and mix it in the obtained first mixture. After returning to room temperature, add the component (E-1) and mix them. Add the component (D-2) to their mixture, mix them evenly, and heat at 100°C for 15 minutes to obtain the biomass epoxy resin composition of Example 7. In addition, the cured product of the biomass epoxy resin composition is produced by the same method as in Example 1.

[0118] <Example 8>

[0119] Prepare the components (A) to (F) in the amounts shown in Table 1. Heat and mix the components (A-1) and (B-1) at 130°C to obtain a first mixture. After uniformly mixing the components (C-1), (F-1) and (D-1) at room temperature, add the component (D-2) and uniformly mix them to obtain a second mixture. The obtained first mixture and second mixture are mixed and heated at 100°C for 15 minutes to obtain the biomass epoxy resin composition of Example 8. In addition, the cured product of the biomass epoxy resin composition is produced by the same method as in Example 1.

[0120] <Comparative Example 1>

[0121] The (A) component and the (B') component were prepared in the amounts shown in Table 1. The (A-1) component and the (B'-1) component were heated at 100°C for 15 minutes to obtain a biomass epoxy resin composition of Comparative Example 1. Thereafter, a cured product was obtained in the same manner as in Example 1.

[0122] <Comparative Example 2>

[0123] The (A) component and the (B) component were prepared in the amounts shown in Table 1. The (A-1) component and the (B-1) component were heated at 100° C. for 15 minutes to obtain a biomass epoxy resin composition of Comparative Example 2. Thereafter, a cured product was obtained in the same manner as in Example 1.

[0124] <Comparative Example 3>

[0125] The (A) component and the (B) component were prepared in the amounts shown in Table 1. The (A-1) component and the (B-2) component were heated at 100° C. for 15 minutes to obtain a biomass epoxy resin composition of Comparative Example 3. Thereafter, a cured product was obtained in the same manner as in Example 1.

[0126] <Comparative Example 4>

[0127] A biomass epoxy resin composition and a cured product thereof were obtained in the same manner as in Example 1 except that the component (C-1) was changed to the component (C'-1) and the amount of the component (C') was changed to the amount shown in Table 1.

[0128] <Comparative Example 5>

[0129] A biomass epoxy resin composition and a cured product thereof were obtained in the same manner as in Example 1 except that the amount of component (D) was changed to the amount shown in Table 1 and the heating time after mixing the first mixture and the second mixture was changed to 60 minutes.

[0130] <Comparative Example 6>

[0131] Prepare the (A) component, (B) component and (E) component in the amounts shown in Table 1. Heat and mix the (A-1) component and (B-1) component at 130°C to obtain a first mixture. After cooling the obtained first mixture to 80°C, add the (E-1) component, mix uniformly, and heat at 100°C for 15 minutes to obtain a biomass epoxy resin composition of Comparative Example 6. In addition, a cured product of the biomass epoxy resin composition was produced by the same method as in Example 1.

[0132] The components shown in Table 1 (components represented by symbols) are as follows.

[0133] [Epoxy resin: component A]

[0134] (A-1)

[0135] Bisphenol A type epoxy resin [jER828 manufactured by Mitsubishi Chemical Corporation] (liquid at room temperature) [curing agent derived from biomass: component B]

[0136] (B-1)

[0137] 4-Aminobenzoic acid (solid at room temperature)

[0138] (B-2)

[0139] 4-Hydroxybenzoic acid (solid at room temperature)

[0140] [Petroleum-derived curing agent: component B']

[0141] (B'-1)

[0142] Acid anhydride curing agent [HN2000 manufactured by Showa Denko Materials Co., Ltd.] (liquid at room temperature)

[0143] [Biomass-derived monomers: component C]

[0144] (C-1)

[0145] Isobornyl (meth)acrylate (IBOMA) (liquid at room temperature) (Tg: 180°C) (C-2)

[0146] Tetrahydrofurfuryl (meth)acrylate (liquid at room temperature) (Tg: 60°C)

[0147] (C-3)

[0148] Tetrahydrofurfuryl acrylate (liquid at room temperature) (Tg: -12℃)

[0149] [Polymerization initiator: component D]

[0150] (D-1)

[0151] Curing agent 328E [made by Akzo Chemical Co., Ltd.]

[0152] (D-2)

[0153] Cobalt Octanoate

[0154] [Inorganic filler: ingredient E]

[0155] (E-1)

[0156] Fused silica [FB74 manufactured by DENKA Corporation] (average particle size: 30 μm)

[0157] [Compatible monomer: component F]

[0158] (F-1)

[0159] Glycidyl methacrylate (GM) (liquid at room temperature) (Tg: 46°C)

[0160] <Evaluation Method>

[0161] The evaluation was performed by the following method. It should be noted that the samples used for the evaluation of (1) gel time and (2) Tg were polymers obtained by polymerizing only the (C) component, the samples used for the evaluation of (3) C14 were biomass epoxy resin compositions, and the samples used for the evaluation of (5) tan δ peak temperature were cured products of the biomass epoxy resin compositions.

[0162] (1) Gel time

[0163] Prepare a gelation tester (No. 153 gel time tester manufactured by Yasuda Seiki Co., Ltd.). Rotate the rotor in a test tube containing 1 ml of the sample. If the gelation of the sample progresses, a certain torque is applied to the rotor, and the rotor falls through the magnetic coupling mechanism, the timer stops, and the time at this time is set as the gelation time of each sample. The measurement is carried out by placing the test tube in an oil bath at 100°C.

[0164] (2)Tg

[0165] A DMA apparatus (DMS6100 manufactured by Hitachi High-Technologies Corporation) was prepared. A test piece (40 mm in length×10 mm in width×1 to 3 mm in thickness) made of a polymer was used and measurement was performed under the following test conditions. The peak top temperature of tan δ in the measurement was defined as Tg.

[0166] {Test conditions}

[0167] Deformation mode: Stretch mode

[0168] Measuring temperature: 25~250℃

[0169] Heating rate: 2℃ / min

[0170] Frequency: 0.2~5Hz

[0171] (3)C14

[0172] The C14 content of each sample was calculated using the following formula (1).

[0173] Content of C14 in the biomass epoxy resin composition (%) = 100 × C14 content in the biomass epoxy resin composition / total carbon content in the biomass epoxy resin composition Formula (1)

[0174] (4) Mixed viscosity

[0175] An E-type viscometer (manufactured by Toki Sangyo Co., Ltd., RE105U) is prepared. As a sample, a mixture of components (A) to (C) is prepared. The mixture is obtained by heating and mixing the components (A) and (B) at 130°C and heating and mixing the component (C) at 100°C. It should be noted that the sample not containing the component (C) is a mixture obtained by heating and mixing the components (A) and (B) at 130°C. The mixed viscosity of each mixture at 60°C is measured. A mixed viscosity of less than 300 mPa·s is recorded as "W", a mixed viscosity of more than 300 mPa·s and less than 1000 mPa·s is recorded as "X", a mixed viscosity of more than 1000 mPa·s and less than 5000 mPa·s is recorded as "Y", a mixed viscosity of more than 5000 mPa·s is recorded as "Z", and other than "Z" are set as good. The reason for using such a sample is that if the component (D) is added and heated, a polymerization reaction is initiated, and the mixed viscosity changes (increases) all the time. In addition, since the content of the component (D) in the biomass epoxy resin composition is small, the mixing viscosity of the biomass epoxy resin composition is not affected by the addition of the component (D).

[0176] (5) tanδ peak temperature

[0177] The above-mentioned DMA apparatus was prepared. The tan δ peak temperature of each sample was measured. When two peaks were obtained, the higher value of the tan δ peak value (intensity) was set as the tan δ peak temperature.

[0178] Table 1 shows the evaluation results of (1) to (5) above for the obtained evaluation samples.

[0179]

[0180] <Results>

[0181] The biomass epoxy resin composition of the embodiment uses a biomass-derived curing agent (B) and a biomass-derived monomer (C), and the content of C14 is 20% or more, so it is excellent in environmental performance. In addition, the biomass epoxy resin composition of the embodiment has excellent workability because the gel time of the polymer is within 20 minutes. Furthermore, the biomass epoxy resin composition of the embodiment has excellent heat resistance because the Tg of the polymer is above 60°C.

[0182] It was confirmed that the mixed viscosity of Examples 1 to 5 and 8 was significantly lower than that of Comparative Examples 2 and 3 in which no biomass-derived monomer (C) was added. In particular, in Examples 3 and 4, by adding 50% by weight or more of the biomass-derived monomer (C), a mixed viscosity equal to or lower than that of the anhydride-cured epoxy resin composition used as a packaging material shown in Example 1 was formed.

[0183] Furthermore, it was confirmed that the mixed viscosity of Example 7 was significantly lower than that of Comparative Example 6 in which no biomass-derived monomer (C) component was added.

[0184] From these results, it was confirmed that the workability was significantly improved by including the biomass-derived monomer (C). In addition, it was confirmed that the workability could be further improved by increasing the content of the biomass-derived monomer (C).

[0185] In Examples 1 to 4, the tan δ peaks were broad, confirming that the epoxy resin cured material was partially compatible with the polymer. On the other hand, in Example 5, two tan δ peaks were obtained, confirming that the epoxy resin cured material was phase-separated from the polymer. As shown in Example 5, it is believed that when the gel time of the polymer is short, the epoxy resin cured material is not sufficiently compatible with the polymer, and the cured material of the biomass epoxy resin composition is formed in a partially phase-separated state.

[0186] The tan δ peak temperature shown in Examples 1 to 4 confirmed that the Tg of the cured biomass epoxy resin composition increased with the increase in the amount of IBOMA added, which has a Tg of 180°C in the single polymer. In Examples 1 and 2, the tan δ peak temperature showed a value between the Tg of the cured epoxy resin and the Tg of the polymer. It is speculated that this is because the cured epoxy resin and the polymer are partially compatible, and the Tg of the entire biomass epoxy resin composition becomes a value between the Tg of the cured epoxy resin and the Tg of the polymer.

[0187] In Examples 3 and 4, the tan δ peak temperature showed a value higher than the Tg of the single polymer. It is presumed that this is because the epoxy resin cured product and the polymer molecular chains are physically entangled and constrained to have a higher Tg value than the single polymer, thereby improving heat resistance.

[0188] As in Example 5, when the epoxy resin cured product and the polymer are partially phase-separated, the lower tan δ peak temperature of the two tan δ peaks shows a value equivalent to the tan δ peak temperature of Comparative Example 2, which is a biomass epoxy resin composition not containing the biomass-derived monomer (C). However, it was confirmed that even when the epoxy resin cured product and the polymer are partially phase-separated, workability and heat resistance can be improved by including the biomass-derived monomer (C).

[0189] From these results, it was confirmed that heat resistance can be improved by including the biomass-derived monomer (C).

[0190] As in Example 6, it was confirmed that even when the Tg of the polymer was relatively low, the mixing viscosity could be reduced compared with Comparative Example 3 which did not contain the biomass-derived monomer (C), and thus the workability could be improved.

[0191] The content of the monomer components in Examples 1 and 8 is the same. In Example 1, only IBOMA whose Tg in the single polymer is 180°C is used, and in Example 8, the same amount of IBOMA and GM whose Tg in the single polymer is 46°C are used. The Tg in the single polymer of IBOMA and GM is greatly different, and the tanδ peak temperature of Example 7 is higher than the tanδ peak temperature of Example 1. It is speculated that this is because the biomass epoxy resin composition contains a compatible monomer (F), and the epoxy resin cured material and the polymer form partial chemical bonds in addition to the physical entanglement of the molecular chains, so the compatibility of the epoxy resin cured material and the polymer is improved, and the heat resistance is improved.

[0192] From these results, it was confirmed that the heat resistance can be improved by including the compatible monomer (F).

[0193] Since Comparative Example 1 does not contain the biomass-derived curing agent (B) and the biomass-derived monomer (C), it is inferior in environmental friendliness.

[0194] Since Comparative Examples 2 and 3 did not contain the biomass-derived monomer (C), the workability was inferior to that of Examples 1 to 6.

[0195] In Comparative Example 4, since the Tg of the polymer was lower than 60° C., the heat resistance was poor.

[0196] In Comparative Example 5, since the gelation time of the polymer at 100°C exceeded 20 minutes, the volatilization of the biomass-derived monomer (C) progressed and the degree of polymerization of the biomass-derived monomer (C) was suppressed. Therefore, it is believed that a low molecular weight polymer was formed and the Tg of the polymer was less than 60°C, resulting in reduced heat resistance.

[0197] The embodiments and examples disclosed this time should be considered as illustrative in all aspects and not restrictive. The scope of the present disclosure is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A biomass epoxy resin composition, comprising an epoxy resin, a biomass-derived curing agent, a biomass-derived monomer, and a polymerization initiator, wherein: The gelation time of the polymer of the monomer at 100°C or below is within 20 minutes, The glass transition temperature of the polymer of the monomer is 60° C. or higher.

2. The biomass epoxy resin composition according to claim 1, wherein The content of radioactive carbon relative to total carbon in the biomass epoxy resin composition is 20% or more.

3. The biomass epoxy resin composition according to claim 1 or 2, wherein The curing agent comprises at least one selected from 4-aminobenzoic acid, 4-hydroxybenzoic acid and protocatechuic acid.

4. The biomass epoxy resin composition according to any one of claims 1 to 3, wherein The monomer comprises at least one selected from ethyl methacrylate, tetrabutyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate and isobornyl (meth)acrylate.

5. The biomass epoxy resin composition according to any one of claims 1 to 4, wherein The polymerization initiator includes at least one selected from hydroperoxides and ketone peroxides, and a metal salt.

6. The biomass epoxy resin composition according to any one of claims 1 to 5, wherein Also contains inorganic fillers.

7. The biomass epoxy resin composition according to any one of claims 1 to 6, wherein Also contains compatible monomers.

8. The biomass epoxy resin composition according to claim 7, wherein The compatible monomer is glycidyl methacrylate.

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