Biomass epoxy resin composition

Abstract

A biomass epoxy resin composition comprising an epoxy resin, a biomass-derived hardener, a biomass-derived monomer and a polymerization initiator, wherein a gel time at 100 °C or less of a polymer derived from the monomer is 20 minutes or less and a glass transition temperature of the polymer derived from the monomer is 60 °C or more.

Description

TECHNICAL AREA

[0001] The present disclosure relates to a biomass epoxy resin composition. STATE OF THE ART

[0002] Epoxy resin possesses excellent thermomechanical properties, electrical properties, moisture resistance, chemical resistance, dimensional stability, and the like, and is therefore frequently used as an insulating material in electrical devices. Epoxy resin is a type of thermosetting resin in which, once cured, the reaction proceeds in the form of a three-dimensional network to create a solid, insoluble, infusible cured product, and it is considered difficult to reuse the cured product. For this reason, most epoxy resin is disposed of after use by incineration or in landfills, etc., and the incineration of epoxy resin emits the greenhouse gas CO2.

[0003] In recent years, reducing CO2 emissions in the context of mitigating global warming has become a pressing issue. Furthermore, there is a demand for a reduction in the use of petroleum resources and a need for materials with lower environmental impact. Against this backdrop, it is proposed to use biomass material with carbon-neutral properties as a raw material for epoxy resin.

[0004] Japanese Patent Application No. 2009-263549 (PTL 1) and Japanese Patent Application No. 2013-181040 (PTL 2) disclose an epoxy resin composition consisting of an epoxy resin and a hardener derived from biomass that is solid at normal temperature. PTL 1 proposes the use of lignin, which has a phenolic skeleton in its molecule, as the hardener, and discloses that a cured epoxy resin product with a glass transition temperature (Tg) of up to 200 °C or higher was obtained. PTL 2 proposes, from the perspective of malleability, the use of a derivative of a plant polyphenol with a relatively low molecular weight as the hardener.

[0005] Furthermore, Japanese National Patent Publication No. 2016-520677 (PTL 3) discloses a multi-component synthetic resin adhesive containing at least one reactive diluent and one reactive resin (including an epoxy resin). PTL 3 aims to increase the biological material content in the synthetic resin adhesive and improve the product's environmental and sustainability properties, and proposes the use of a biological reactive diluent and a reactive resin to achieve this objective. LIST OF CAPLETS PATENT LITERATURE PTL 1: Japanese Disclosure Document No. 2009-263549 PTL 2: Japanese Disclosure Document No. 2013-181040 PTL 3: Japanese National Patent Publication No. 2016-520677 BRIEF DESCRIPTION OF THE INVENTIONAL PROBLEM

[0006] However, both PTL 1 and 2 use a hardener that is solid at normal temperature, resulting in poor processability compared to a resin composition containing a liquid hardener. As disclosed in PTL 1, particularly when lignin, which has a high molecular weight, is used as the hardener, the viscosity of the resin composition increases, further impairing processability. Furthermore, as disclosed in PTL 2, when pyrogallol, a polyphenol derivative, is used as the hardener, processability is expected to improve compared to lignin, but there is room for improvement in heat resistance.

[0007] However, PTL 3 uses a biomass-derived reactive diluent as a constituent component, but does not investigate its processability or heat resistance. It is known that heat resistance is particularly influenced by the structure of a cured product made from a multi-component resin; therefore, controlling the structure of the cured product is important.

[0008] The present disclosure was developed to solve the problems described above, and one of its objectives is to provide a biomass epoxy resin composition that is excellent in terms of environmental friendliness and also exhibits both processability and heat resistance. SOLUTION TO THE PROBLEM

[0009] The inventors of the present invention have conducted intensive research to fulfill the aforementioned problem and have consequently found that the combination of an epoxy resin, a biomass-derived hardener, a biomass-derived monomer, and a polymerization initiator has the effect of achieving excellent environmental friendliness as well as processability and heat resistance.

[0010] The present disclosure relates to a biomass epoxy resin composition, as described below.

[0011] Biomass epoxy resin composition comprising an epoxy resin, a biomass-derived hardener, a biomass-derived monomer and a polymerization initiator, wherein a gel time at 100 °C or less of a polymer obtained from the monomer is 20 minutes or less and a glass transition temperature of the polymer obtained from the monomer is 60 °C or higher. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0012] The present disclosure makes it possible to provide a biomass epoxy resin composition that is excellent in terms of environmental friendliness and also exhibits both processability and heat resistance. DESCRIPTION OF EXECUTION FORMS

[0013] The following describes embodiments of the present disclosure. Design 1. <biomasse-epoxidharzzusammensetzung>

[0014] A biomass-epoxy resin composition according to the present embodiment comprises an epoxy resin (A), a hardener derived from biomass (B), a monomer derived from biomass (C), and a polymerization initiator (D). The gel time at 100 °C or less of a polymer derived from the monomer derived from biomass (C) is 20 minutes or less. The Tg of the polymer derived from the monomer derived from biomass (C) is 60 °C or more. Hereinafter, the polymer derived from the monomer derived from biomass (C) may also be referred to simply as "the polymer". (epoxy resin (A))

[0015] The epoxy resin (A) contained in the biomass-epoxy resin composition according to the present embodiment is a compound having two or more oxirane rings (epoxy groups) per molecule. The state of the epoxy resin (A) is not subject to any particular restrictions, but with regard to dissolving the solid hardener derived from biomass (B), the epoxy resin (A) is preferably liquid at room temperature.

[0016] Examples of epoxy resin (A) of this type include a bisphenol-A type epoxy resin, a bisphenol-F type epoxy resin, a cresol-novolac type epoxy resin, an alicyclic epoxy resin, a glycidylamine type epoxy resin, and the like. Among these epoxy resins (A), bisphenol-A type and bisphenol-F type epoxy resins are preferred with respect to processability and heat resistance. Furthermore, a polyfunctional epoxy resin is preferred when excellent heat resistance is required.

[0017] The epoxy resin (A) can be derived from petroleum or from biomass. Furthermore, only one type of epoxy resin (A) can be used alone, or two or more types can be used in combination. If two or more types are used in combination, those present in the combination are not subject to any special restrictions. (Hardener derived from biomass (B))

[0018] The biomass epoxy resin composition according to the present embodiment includes the hardener derived from biomass (B). Including the hardener derived from biomass (B) results in a biomass epoxy resin composition that is exceptionally environmentally friendly.

[0019] Preferably, the hardener derived from biomass (B) is a compound with an aromatic ring, with regard to its heat resistance. Examples of this type of hardener derived from biomass (B) include aromatic compounds such as 4-aminobenzoic acid, 4-hydroxybenzoic acid, and protocatechuic acid; industrial lignin obtained by isolating lignin from a phenol-based polymer compound by various processes; and the like. Among these hardeners derived from biomass (B), 4-aminobenzoic acid, 4-hydroxybenzoic acid, and protocatechuic acid are preferred. This is because each of 4-aminobenzoic acid, 4-hydroxybenzoic acid, and protocatechuic acid has a low molecular weight, and the use of a low molecular weight hardener derived from biomass (B) makes it possible to obtain a biomass-based epoxy resin composition with low mixing viscosity and excellent processability.

[0020] Only one type of hardener derived from biomass (B) can be used alone, or two or more types can be used in combination. Furthermore, the hardener derived from biomass (B) can be obtained entirely from biomass or partially from biomass.

[0021] The content of the hardener derived from biomass (B) can be adjusted based on the assumption that the epoxy group in the epoxy resin molecule (A) and a functional group in the biomass-derived hardener molecule (B), which can react with the epoxy group (such as an active hydrogen of an amino group, a hydroxyl group, a carboxyl group, and / or an acid anhydride), react with each other in a 1:1 chemical equivalent weight ratio, where the ratio of the equivalent weight of the functional group in the biomass-derived hardener molecule (B) to the epoxy group in the epoxy resin molecule (A) becomes 0.3 to 3.0. If the equivalent weight ratio lies outside the aforementioned range, there is a possibility that properties such as heat resistance will not be sufficiently exhibited.

[0022] Furthermore, it is preferred to adjust the content of the hardener derived from biomass (B) such that the number of active hydrogens in the epoxy group in the epoxy resin (A) is equal to that in the functional group in the hardener derived from biomass (B). For example, if a bisphenol-A type epoxy resin with an epoxy equivalent weight of 190 g / eq is used as the epoxy resin (A) and 4-aminobenzoic acid is used as the hardener derived from biomass (B), the amount of 4-aminobenzoic acid is to be adjusted to 24.0 parts by weight relative to 100 parts by weight of the bisphenol-A type epoxy resin. For example, if the same bisphenol-A type epoxy resin is used as the epoxy resin (A) and 4-hydroxybenzoic acid is used as the hardener derived from biomass (B), the amount of 4-hydroxybenzoic acid is to be adjusted to 36.4 parts by weight relative to 100 parts by weight of the bisphenol-A type epoxy resin. (Monomer (C) derived from biomass)

[0023] The biomass epoxy resin composition according to the present embodiment includes the monomer obtained from biomass (B). If the monomer obtained from biomass (C) is included, a biomass epoxy resin composition can be obtained that is excellent in terms of environmental friendliness and processability.

[0024] Examples of monomers derived from biomass (C) include ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, tetrabutyl methacrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, glycidyl methacrylate, neopentyl glycol dimethacrylate, and the like. Only one type of monomer derived from biomass (C) can be used alone, or two or more types can be used in combination. Furthermore, the monomer obtained from biomass (B) can be derived entirely from biomass or partially from biomass. As long as the monomer obtained from biomass (C) is present, a monomer derived from petroleum may also be included.

[0025] Among these monomers derived from biomass (C), ethyl methacrylate, tetrabutyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, isobornyl methacrylate, and the like are preferred, with isobornyl methacrylate being further preferred. This is because isobornyl methacrylate has a high Tg (Tg = 180 °C), and thus, by mixing isobornyl methacrylate with the epoxy resin (A) and its compatibility with it, a biomass-epoxy resin composition can be obtained that exhibits excellent heat resistance. Therefore, a biomass-epoxy resin composition containing isobornyl methacrylate can be suitably used in applications where excellent heat resistance is required.

[0026] As described below, in a cured product of the biomass-epoxy resin composition according to the present embodiment, the Tg of the polymer is 60 °C or higher. Although the biomass (C)-derived monomer described above includes one with a Tg lower than 60 °C, at least two biomass (C)-derived monomers, namely one biomass (C)-derived monomer with a Tg of 60 °C or higher and one biomass (C)-derived monomer with a Tg lower than 60 °C, can be combined to adjust the Tg of the resulting polymer to 60 °C or higher.

[0027] The percentage of monomer derived from biomass (C) is 10 to 70 wt% relative to the sum of the epoxy resin (A), the hardener derived from biomass (B), and the monomer derived from biomass (C). If the percentage of monomer derived from biomass (C) is less than 10 wt%, the effect obtained from the monomer derived from biomass (C) may be minimal. If the percentage of monomer derived from biomass (C) is more than 70 wt%, the biomass-epoxy resin composition may be brittle and poorly formable. (Polymerization initiator (D))

[0028] The biomass-epoxy resin composition according to the present embodiment includes the polymerization initiator (D). The polymerization initiator (D) is a compound capable of initiating the polymerization of the monomer obtained from biomass (C), and examples include radical initiators that can produce active radicals, acids and / or the like through the action of light or heat, redox initiators that can produce radicals through redox reactions, and the like.

[0029] Examples of polymerization initiators (D) include organic peroxides, such as hydroperoxides, dialkyl peroxides, peroxy esters, diacyl peroxides, peroxycarbonates, peroxyketals, and ketone peroxides; combinations of the organic peroxide and a reducing agent, such as a metal salt and an amine; and the like. Among these polymerization initiators (D), a combination of a hydroperoxide and a metal salt, as well as a combination of a ketone peroxide and a metal salt, are preferred because they can efficiently generate radicals even at low temperatures. Examples of the hydroperoxide include tert-butyl hydroperoxide, cumene hydroperoxide, and the like. Examples of the ketone peroxide include methyl ethyl ketone peroxide, cyclohexanone peroxide, and the like. Examples of the metal salt include cobalt salts, such as cobalt naphthenate and cobalt octoate, vanadium compounds, such as vanadium pentoxide, and the like.

[0030] The content of the polymerization initiator (D) is, depending on the type of monomer obtained from the biomass (C) to be used, from 0.001 to 20 parts by weight, preferably from 0.005 to 10 parts by weight, relative to 100 parts by weight of the monomer obtained from biomass (C). If the content of the polymerization initiator (D) falls within the aforementioned range, the gel time of the polymer described below can fall within a suitable range. (Hardening accelerator)

[0031] The biomass epoxy resin composition according to the present embodiment may include a curing accelerator for the purpose of increasing the curing rate of the epoxy resin (A). The curing accelerator is not subject to any particular restrictions as long as it can facilitate the curing of the epoxy resin (A), and examples include tertiary amine-based accelerators such as benzyldimethylamine, imidazole-based accelerators such as 2-ethyl-4-methylimidazole, phosphorus-based accelerators such as triphenylphosphine, organic metals such as zinc octoate, and the like. Only one type of curing accelerator may be used alone, or two or more types may be used in combination.The concentration of the hardening accelerator may be adjusted to suit the type of epoxy resin (A) to be used and / or the hardener obtained from biomass (B) to be used, and is typically 0.1 to 100 parts by weight relative to 100 parts by weight of the epoxy resin (A). (Properties of the biomass epoxy resin composition) [Gel time]

[0032] In a cured product of the biomass-epoxy resin composition according to the present embodiment, the gel time of the polymer at 100 °C or less is 20 minutes or less. This is because if the gel time of the polymer at 100 °C or less is more than 20 minutes, the volatilization of the monomer derived from biomass (C) continues, and a reaction of the epoxy resin (A) with the hardener derived from biomass (B) also continues, causing an increase in viscosity. This, in turn, reduces the degree of polymerization of the monomer derived from biomass (C), resulting in a diminished demonstration of the effect of the addition of the monomer derived from biomass (C). Preferably, the gel time of the polymer at 100 °C or less is 18 minutes or less. The gel time is preferably short, but with regard to the moldability of the biomass-epoxy resin composition, it is preferably 30 seconds or more.

[0033] The gel time can be measured, for example, using the procedure described below. A gelation tester (No. 153 GEL TIME TESTER, manufactured by Yasuda Seiki Seisakusho, Ltd.) is used as the measuring device. A rotor is set in motion in a test tube containing 1 ml of a polymer sample. As the sample gels and the rotor receives a certain amount of torque, the magnetic coupling system releases the rotor, and the timer stops. The time at this point is considered the gel time. [Glass transition temperature]

[0034] In a cured product of the biomass-epoxy resin composition according to the present embodiment, the Tg of the polymer is 60 °C or higher. If the Tg of the polymer is less than 60 °C, the heat resistance is low. Preferably, the Tg of the polymer is 100 °C or higher. The Tg is preferably high, but can, for example, be 300 °C or lower.

[0035] The temperature difference (Tg) can be measured, for example, using the procedure described below. A Dynamic Mechanical Analyzer (DMA) (DMS6100, manufactured by Hitachi High-Tech Science Corporation) is used as the measuring device. A test sample (40 mm long, 10 mm wide, 1 to 3 mm thick) made of the polymer is subjected to measurement under the test conditions specified below, and the upper peak temperature of the loss tangent (tan δ) is considered the Tg. <testbedingungen> Deformation mode: Tension mode Measuring temperature: 25 to 250 °C Heating rate: 2 °C / minute Frequency: 0.2 to 5 Hz [Phase structure]

[0036] In the present embodiment, the phase structure of the cured product of the biomass-epoxy resin composition (hereinafter also referred to simply as "the phase structure") affects physical properties such as heat resistance and mechanical strength. Examples of the phase structure include a state in which an epoxy-cured product (which is a cured product derived from the epoxy resin (A) and the hardener derived from biomass (B)) is not mixed with the polymer in a compatible state, but rather separated from it—a state of phase separation—and a state in which the epoxy-cured product is mixed with the polymer in a compatible state. The phase structure can be identified based on the peak shape and peak temperature of the dynamic viscoelasticity of the cured product, tan δ.

[0037] If the Tg of the epoxy resin-cured product (hereinafter also referred to as Tg1) differs from the Tg of the polymer (hereinafter also referred to as Tg2), two tan-δ peaks will be observed when these two phases are completely separated from each other, which can be attributed to the respective Tgs.

[0038] Furthermore, when the epoxy resin-cured product is mixed with the polymer in a compatible state, a tan-δ peak is observed.The following states are conceivable as the state in which the epoxy-cured product is mixed with the polymer in a compatible state, for example: (1) a state in which each of the epoxy-cured product and the polymer has a functional group that can be chemically bonded together; (2) a state in which each of the epoxy-cured product and the polymer forms a network structure but does not have a functional group that can be chemically bonded together; and (3) a state in which one of the epoxy-cured product and the polymer is a long-chain polymer that forms a network structure, and the other is a long-chain polymer that does not form a network structure and does not have a functional group that can be chemically bonded together.In state (1), the two network structures, or a network structure and a chain structure, are chemically linked to form a single network structure, and a tan-δ peak is observed. In state (2), when the two network structures are uniformly and physically interwoven to form an interpenetrating polymer network (IPN), a tan-δ peak is observed. In state (3), the long-chain polymer is physically interwoven with the other network structure to form a half-IPN structure, and a tan-δ peak is observed.

[0039] Furthermore, there may be another case in which the tan-δ peak is observed as two peaks or as a shoulder peak at one or more positions that differ from the tan δs of the epoxy-cured product alone and the polymer alone. The following conditions are conceivable as states of this type, for example: (1) a state in which each of the epoxy-cured product and the polymer has a functional group that can be chemically linked; (2) a state in which the network structure of the epoxy-cured product and the network structure of the polymer are uniformly and physically interwoven to form an IPN structure; and (3) a state in which the long-chain polymer is physically interwoven with the other network structure to form a half-IPN structure.In state (1), the compatibility between the epoxy-cured product and the polymer is improved by chemical bonding; however, if there are few functional groups or if the polymer has a high molecular weight, partial or total phase separation may occur. In state (2), the polymer undergoes phase separation if the entanglement is partially weak. In state (3), similar to state (2), the polymer undergoes partial or total phase separation if the entanglement between molecular chains is partially weak.

[0040] In the present embodiment, when Tg2 is smaller than Tg1, the epoxy resin-cured product and the polymer in the biomass-epoxy resin composition are preferably in a state of phase separation. In this case, Tg1 alone corresponds to the Tg of the epoxy resin (A), so that a reduction in the Tg of the biomass-epoxy resin composition as a whole can be prevented.

[0041] On the other hand, if Tg2 is greater than Tg1, it is preferred that the epoxy-cured product and the polymer in the biomass-epoxy resin composition are mixed in a fully compatible or partially compatible state. In this case, Tg1 can be greater than the Tg of the epoxy resin (A) alone, which allows suitable use in applications where even better heat resistance is required. (Radiocarbon)

[0042] The biomass epoxy resin composition according to the present embodiment includes a radiocarbon (carbon-14; hereinafter also referred to as "C14"). C14 is always present in the atmosphere in a certain ratio. Plants absorb CO2 from the atmosphere as they grow, so the C14 content in plants corresponds to that in the atmosphere. On the other hand, fossil resources such as petroleum do not contain C14, so it is possible to distinguish carbon derived from biomass from carbon derived from petroleum. The C14 concentration in the current atmosphere is about 100 pMC (percent modern carbon). Therefore, if a particular biomass plastic is produced with substances derived 100% from biomass, the sample should contain approximately 100 pMC. Conversely, if produced with substances derived from petroleum, the sample should contain essentially 0 pMC.For example, a sample consisting of 50% substances derived from biomass and 50% substances derived from petroleum (the numerical values ​​are based on the amount of carbon) should have approximately 50 pMC. Therefore, by determining the C14 content in the biomass epoxy resin composition, it is possible to assess the degree of environmental impact potentially caused by the biomass epoxy resin composition.

[0043] The percentage of C14 relative to the total carbon in the biomass epoxy resin composition according to the present embodiment is 20% or more. The percentage of C14 is calculated by the following equation (1). Percentage 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)

[0044] If the percentage of C14 in the biomass epoxy resin composition is less than 20%, the effect as a carbon balancing material is small. (Mixed viscosity)

[0045] The mixed viscosity of the biomass-epoxy resin composition at 60 °C is preferably 5000 mPa·s or less, more preferably 1000 mPa·s or less, and further preferably 300 mPa·s or less, with regard to processability. In the present embodiment, the mixed viscosity of the biomass-epoxy resin composition is measured with an E-type viscometer. The mixed viscosity is preferably low, but can, for example, be 10 mPa·s or more. (Applications)

[0046] The biomass epoxy resin composition according to the present embodiment is not subject to any specific restrictions regarding its intended use and can be used in various applications. For example, it can be dissolved in organic solvent for use as a coating for engines, or it can be mixed with a filler, as in embodiment 2 below, for use as a molding resin for engines and power modules. <Verfahren zum Herstellen einer Biomasse-Epoxidharzzusammensetzung>

[0047] The process for producing a biomass-epoxy resin composition according to the present embodiment is not subject to any particular limitations. For example, the epoxy resin (A) and the hardener derived from biomass (B) are mixed together at room temperature or during heating, thereby obtaining a first mixture. The heating temperature is, for example, in the range of 40 to 180 °C. The monomer derived from biomass (C) and the polymerization initiator (D) are mixed together at room temperature, thereby obtaining a second mixture. The first and second mixtures thus obtained are mixed during heating, thereby obtaining a biomass-epoxy resin composition.The heating temperature and heating time can optionally be determined to be suitable for the epoxy resin (A), the hardener derived from biomass (B), and the monomer derived from biomass (C) that are to be used. For example, the heating temperature may be in the range of 40 to 180 °C, but preferably in the range of 40 to 120 °C to minimize the volatilization of the monomer derived from biomass (C). The heating time may be in the range of 1 to 180 minutes. The degree of polymerization of the monomer derived from biomass (C) varies depending on both the heating temperature and the heating time, and, for example, the degree of polymerization achieved by short-term heating at a high temperature may be the same as that achieved by long-term heating at a low temperature.

[0048] A solvent may be used when the epoxy resin (A) and the biomass-derived hardener (B) are mixed. The solvent is not subject to any particular restrictions and examples include toluene, methyl ethyl ketone, and the like.

[0049] Alternatively, the epoxy resin (A), the biomass-derived hardener (B), and the biomass-derived monomer (C) can be mixed together, for example, at room temperature or during heating. Then, the polymerization initiator (D) can be added and mixed again, either at room temperature or during heating. The heating temperature for mixing the epoxy resin (A), the biomass-derived hardener (B), and the biomass-derived monomer (C) is, for example, in the range of 40 to 180 °C. The heating temperature after adding the polymerization initiator (D) is, for example, in the range of 40 to 180 °C.

[0050] The conditions for curing the biomass epoxy resin composition are not subject to any particular restrictions, and, for example, the heating temperature can range from 30 to 300 °C and the heating time can range from 1 minute to 100 hours. Design 2.

[0051] The biomass epoxy resin composition according to the present embodiment further includes an inorganic filler (E). With the biomass epoxy resin composition containing the inorganic filler (E), a biomass epoxy resin composition with the desired mechanical strength and linear coefficient of expansion can be obtained. Only the differences from embodiment 1 are described below. (Inorganic filler (E))

[0052] The inorganic filler (E) is not subject to any particular restrictions and examples include particles of a metal oxide, such as aluminum oxide, zinc oxide, indium tin oxide (ITO), magnesium oxide, beryllium oxide, and titanium oxide; particles of a metal nitride, such as boron nitride, silicon nitride, and aluminum nitride; particles of a carbon compound, such as silicon carbide, graphite, diamond, amorphous carbon, carbon black, and carbon fibers; powders of a silicon dioxide compound, such as quartz and fused silica; and the like. Only one of these may be used alone, or two or more may be used in combination. Among these, aluminum oxide, zinc oxide, magnesium oxide, beryllium oxide, titanium oxide, boron nitride, silicon nitride, aluminum nitride, diamond, quartz, fused silica, and the like are preferred with regard to their electrically insulating properties.

[0053] The average particle size of the inorganic filler (E) is preferably 1 nm to 100 µm, more preferably 1 nm to 80 µm. If the average particle size of the inorganic filler (E) is less than 1 nm, the viscosity of the biomass-epoxy resin composition is high, which may lead to impaired processability and / or moldability. If the average particle size of the inorganic filler (E) is greater than 100 µm, the cured product of the biomass-epoxy resin composition may be less strong and / or the inorganic filler (E) may tend to sediment during storage of the biomass-epoxy resin composition.

[0054] The content of the inorganic filler (E) is preferably 40 to 90 wt.%, more preferably 70 to 85 wt.%, relative to the biomass-epoxy resin composition as a whole. If the content of the inorganic filler (E) is less than 40 wt.%, it may be impossible to obtain a cured biomass-epoxy resin product that exhibits the desired mechanical strength and coefficient of thermal expansion. If the content of the inorganic filler (E) is more than 90 wt.%, the viscosity of the biomass-epoxy resin composition is high, which may lead to impaired processability and / or moldability. (Coupling device)

[0055] To improve the wettability between the inorganic filler (E) and the biomass-epoxy resin composition, to increase the interface between the inorganic filler (E) and the biomass-epoxy resin composition, and to improve the dispersibility of the inorganic filler (E), a coupling treatment with a coupling agent for the inorganic filler (E) can be carried out, for example. Examples of coupling agents of this type are γ-glycidoxypropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and the like. Only one of these can be used alone, or two or more can be used in combination.

[0056] The content of the coupling agent can be determined to be suitable for the type of epoxy resin (A) and / or inorganic filler (E) and the like, and for example it is 0.01 to 5 parts by weight relative to 100 parts by weight of the epoxy resin (A). (Manufacturing process)

[0057] The process for mixing the inorganic filler (E) is not subject to any particular restrictions, and, for example, the inorganic filler (E) can be mixed in the step in which the epoxy resin (A) and the biomass-derived hardener (B) are mixed together at normal temperature or during heating to obtain an initial mixture. Alternatively, the inorganic filler (E) can be mixed in the step in which the initial and subsequent mixtures are mixed while being heated.

[0058] Alternatively, the inorganic filler (E) can be mixed in the step in which the epoxy resin (A), the hardener derived from biomass (B) and the monomer derived from biomass (C) are mixed together, for example at normal temperature or during heating.

[0059] The coupling treatment of the inorganic filler (E) with a coupling agent simply needs to be carried out using a conventionally known method before the inorganic filler (E) is mixed. Design 3.

[0060] The biomass epoxy resin composition according to the present embodiment further includes a compatible monomer (F). With the biomass epoxy resin composition containing the compatible monomer (F), a portion of the epoxy-cured product and a portion of the polymer form a chemical bond with each other, thereby improving the compatibility between the epoxy-cured product and the polymer. As a result, a biomass epoxy resin composition with improved heat resistance can be obtained. Only the differences from embodiment 1 are described below. (Compatible monomer (f))

[0061] Preferably, the compatible monomer (F) is a monomer with at least one functional group selected from the group consisting of a first functional group that reacts with the epoxy resin (A) and the monomer obtained from biomass (C), and a second functional group that reacts with the hardener obtained from biomass (B) and the monomer obtained from biomass (C).

[0062] Examples of the compatible monomer (F) with the first functional group are acrylates and methacrylates, such as methacrylamide, 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 4-hydroxyphenyl(meth)acrylate, 4-vinylphenol and β-carboxyethyl acrylate, styrenes, such as p-acetoxystyrene, o-acetoxystyrene, m-acetoxystyrene, 3-methoxy-4-acetoxystyrene and p-hydroxyphenylstyrene and the like.

[0063] Examples of the compatible monomer (F) with the second functional group are glycidyl(meth)acrylate, methylglycidyl(meth)acrylate, (meth)allylglycidyl ether, (meth)allylmethylglycidyl ether, 3,4-epoxycyclohexylmethyl(meth)acrylate, 4-hydroxybutylacrylate glycidyl ether and the like.

[0064] Only one of these can be used alone, or two or more can be used in combination. Of these, glycidyl methacrylate is preferred from a compatibility point of view.

[0065] The content of the compatible monomer (F) can be adjusted, if necessary, to be suitable for the type of epoxy resin (A), the biomass-derived hardener (B), and the biomass-derived monomer (C). Furthermore, the content of the epoxy resin (A) or the biomass-derived hardener (B) can be adjusted to be suitable for the content of the compatible monomer (F).

[0066] The content of the compatible monomer (F) can be adjusted such that, based on the assumption that the epoxy group in the epoxy resin molecule (A) and a functional group in the compatible monomer molecule (F), which can react with the epoxy group (such as an active hydrogen of an amino group, a hydroxyl group, a carboxyl group, an acetoxy group, and / or an acid anhydride), react with each other in a 1:1 chemical equivalent weight ratio, where the ratio of the equivalent weight of the functional group in the compatible monomer molecule (F) to the epoxy group in the epoxy resin molecule (A) changes from 0.3 to 3.0. If the equivalent weight ratio lies outside the aforementioned range, there is a possibility that properties such as heat resistance will not be sufficiently exhibited.

[0067] The content of the compatible monomer (F) can be adjusted such that, based on the assumption that the functional group in the molecule of the hardener derived from biomass (B), which can react with an epoxide group, and the epoxide group in the molecule of the compatible monomer (F) react with each other in a 1:1 ratio of chemical equivalent weight, the ratio of the equivalent weight of the functional group in the molecule of the hardener derived from biomass (B) to the epoxide group in the molecule of the compatible monomer (F) becomes 0.3 to 3.0. If the equivalent weight ratio lies outside the aforementioned range, there is a possibility that properties such as heat resistance will not be sufficiently exhibited. (Manufacturing process)

[0068] The process for mixing the compatible monomer (F) is not subject to any particular restrictions, and, for example, the compatible monomer (F) can be mixed in the step in which the monomer obtained from biomass (C) and the polymerization initiator (D) are mixed together at room temperature to obtain the second mixture. Alternatively, the compatible monomer (F) can be mixed in the step in which the first and second mixtures are mixed together while being heated.

[0069] Alternatively, the compatible monomer (F) can be mixed in the step in which the epoxy resin (A), the hardener derived from biomass (B) and the monomer derived from biomass (C) are mixed together, for example at normal temperature or during heating. [Examples]

[0070] The present revelation is described in detail below with examples, but these are not intended to limit the scope of the present revelation. <Beispiel 1>

[0071] Components (A) to (D) were each prepared in the amounts specified in Table 1. Component (A-1) and component (B-1) were mixed together while heated at 130 °C to obtain a first mixture. Components (C-1) and (D-1) were mixed together at room temperature for uniformity, after which component (D-2) was added and mixed for uniformity to obtain a second mixture. The first mixture and the second mixture thus obtained were combined and heated at 100 °C for 15 minutes to obtain a biomass epoxy resin composition of Example 1. Additionally, the biomass epoxy resin composition thus obtained was 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. <Beispiele 2 bis 4>

[0072] A biomass epoxy resin composition and a cured product thereof were obtained in the same manner as in Example 1, except that the amounts of component (C) and component (D) were changed to the amounts specified in Table 1. <Beispiel 5>

[0073] A biomass epoxy resin composition and a cured product thereof were obtained in the same way as in Example 1, except that the amount of component (D) was changed to the amount specified in Table 1 and the heating time after mixing the first mixture and the second mixture was changed to 5 minutes. <Beispiel 6>

[0074] A biomass epoxy resin composition and a cured product thereof were obtained in the same manner as in Example 1, except that component (B-1) was changed to component (B-2), component (C-1) was changed to component (C-2), and the amounts of components (B) to (D) were changed to the amounts specified in Table 1. <Beispiel 7>

[0075] Components (A) to (E) were each prepared in the amounts specified in Table 1. Component (A-1) and component (B-1) were mixed together while heated at 130 °C to obtain an initial mixture. This initial mixture and component (C-1) were mixed together while heated at 100 °C, and then the temperature was returned to normal. Component (E-1) was added and mixed. Component (D-2) was added to the resulting mixture and mixed for uniformity. The mixture was then heated at 100 °C for 15 minutes to obtain a biomass epoxy resin composition from Example 7. A cured product of the biomass epoxy resin composition was also prepared in the same manner as in Example 1. <Beispiel 8>

[0076] Components (A) to (F) were each prepared in the amounts specified in Table 1. Component (A-1) and Component (B-1) were mixed together while heated at 130 °C to obtain a first mixture. Component (C-1), Component (F-1), and Component (D-1) were mixed together at room temperature for uniformity, after which Component (D-2) was added and mixed for uniformity to obtain a second mixture. The first mixture and the second mixture thus obtained were combined and heated at 100 °C for 15 minutes to obtain a biomass epoxy resin composition from Example 8. A cured product of the biomass epoxy resin composition was also prepared in the same manner as in Example 1. <Vergleichsbeispiel 1>

[0077] Component (A) and component (B') were each prepared in the quantities specified in Table 1. Component (A-1) and component (B'-1) were heated at 100 °C for 15 minutes to obtain a biomass-epoxy resin composition of Comparative Example 1. From this point on, the same process as in Example 1 was carried out to obtain a cured product. <Vergleichsbeispiel 2>

[0078] Component (A) and component (B') were each prepared in the quantities specified in Table 1. Component (A-1) and component (B-1) were heated at 100 °C for 15 minutes to obtain a biomass-epoxy resin composition of Comparative Example 2. From this point on, the same process as in Example 1 was carried out to obtain a cured product. <Vergleichsbeispiel 3>

[0079] Component (A) and component (B') were each prepared in the quantities specified in Table 1. Component (A-1) and component (B-2) were heated at 100 °C for 15 minutes to obtain a biomass-epoxy resin composition of Comparative Example 3. From this point on, the same process as in Example 1 was carried out to obtain a cured product. <Vergleichsbeispiel 4>

[0080] A biomass epoxy resin composition and a cured product thereof were obtained in the same manner as in Example 1, except that component (C-1) was changed to component (C'-1) and the amount of component (C') was changed to the amount specified in Table 1. <Vergleichsbeispiel 5>

[0081] A biomass epoxy resin composition and a cured product thereof were obtained in the same way as in Example 1, except that the amount of component (D) was changed to the amount specified in Table 1 and the heating time after mixing the first mixture and the second mixture was changed to 60 minutes. <Vergleichsbeispiel 6>

[0082] Component (A), component (B), and component (E) were each prepared in the amounts specified in Table 1. Component (A-1) and component (B-1) were mixed together while heated at 130 °C to obtain an initial mixture. This initial mixture was cooled to 80 °C, whereupon component (E-1) was added and mixed for uniformity, followed by heating at 100 °C for 15 minutes to obtain a biomass epoxy resin composition of Comparative Example 6. A cured product of the biomass epoxy resin composition was also prepared in the same manner as in Example 1.

[0083] The components listed in Table 1 (the components represented by symbols) are as follows. [Epoxy resin: Component A] (A-1) Bisphenol-A type epoxy resin [jER828, manufactured by Mitsubishi Chemical Corporation] (liquid at normal temperature) [Hardener derived from biomass: Component B] (B-1) 4-Aminobenzoic acid (solid at normal temperature) (B-2) 4-Hydroxybenzoic acid (solid at normal temperature) [Petroleum-derived hardeners: Component B'] (B'-1) Acid anhydride hardener [HN2000, manufactured by Showa Denko Materials Co., Ltd.] (liquid at normal temperature) [Monomer derived from biomass: Component C] (C-1) Isobornyl(meth)acrylate (IBOMA) (liquid at normal temperature) (Tg, 180 °C) (C-2) Tetrahydrofurfuryl(meth)acrylate (liquid at normal temperature) (Tg, 60 °C) (C-3) Tetrahydrofurfuryl acrylate (liquid at normal temperature) (Tg, -12 °C) Polymerization initiator: Component D] (D-1) Hardener 328E [manufactured by AkzoNobel Specialty Chemicals] (D-2) Cobalt octoate (Inorganic filler: Component E) (E-1) Quartz glass [FB74, manufactured by Denka Company Limited] (average particle size, 30 µm) (Compatible monomer: component F] (F-1) Glycidyl methacrylate (GM) (liquid at normal temperature) (Tg, 46 °C) <bewertungsverfahren>

[0084] The evaluation was carried out in the manner described below. Each of the samples used in the gel time evaluation (1) and the sample used in the Tg evaluation (2) was a polymer obtained by polymerization of component (C) alone; a sample used in the C14 evaluation (3) was a biomass epoxy resin composition; and a sample used in the tan-8 peak temperature evaluation (5) was a cured product of the biomass epoxy resin composition. (1) Time

[0085] A gelation tester (No. 153 GEL TIME TESTER, manufactured by Yasuda Seiki Seisakusho, Ltd.) was prepared. A rotor was set in motion in a test tube containing 1 ml of sample. As the sample gelled and the rotor reached a specific torque, the magnetic coupling system released the rotor, and the timer stopped. This time was considered the gelation time of the sample. The measurement was performed by heating the test tube to 100 °C in an oil bath. (2) Day

[0086] A DMA device (DMS6100, manufactured by Hitachi High-Tech Science Corporation) was prepared. A test sample (40 mm long, 10 mm wide, 1 to 3 mm thick) consisting of the polymer was subjected to measurement under the test conditions specified below. The upper peak temperature of tan-δ during this measurement was considered Tg. <testbedingungen> Deformation mode: Tension mode Measuring temperature: 25 to 250 °C Heating rate: 2 °C / minute Frequency: 0.2 to 5 Hz (3) C14

[0087] The percentage content of C14 in the sample was calculated using the following equation (1). Percentage 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) (4) Mixed viscosity

[0088] An E-type viscometer (RE105U, manufactured by Toki Sangyo Co., Ltd.) was prepared. One sample consisted of a mixture containing components (A) through (C). This mixture was prepared by mixing component (A) and component (B) while heating at 130 °C and by adding component (C) while heating at 100 °C. A sample excluding component (C) was a mixture prepared by mixing component (A) and component (B) while heating at 130 °C. The viscosity of the mixture at 60 °C was measured. A mixed viscosity of less than 300 mPa·s was rated as “W”, not less than 300 mPa·s and less than 1000 mPa·s as “X”, not less than 1000 mPa·s and less than 5000 mPa·s as “Y”, and 5000 mPa·s or more as “Z”; all ratings except “Z” were considered good.The reason such samples were used was that the addition of component (D) and heating initiate a polymerization reaction and change (increase) the mixture viscosity at any given moment. It should be noted that, since the content of component (D) in the biomass-epoxy resin composition is low, the addition of component (D) does not affect the mixture viscosity of the biomass-epoxy resin composition. (5) Tan δ peak temperature

[0089] The DMA apparatus described above was prepared. The tan-δ peak temperature of the sample was measured. If two peaks were obtained, the higher tan-δ peak value (intensity) was considered the tan-δ peak temperature.

[0090] The results of assessments (1) to (5) for the assessment samples are listed in Table 1. <ergebnisse>

[0091] Each of the biomass-based epoxy resin compositions from the examples was produced using the biomass-derived hardener (B) and the biomass-derived monomer (C), and had a C14 content of 20% or more, thus demonstrating excellent environmental friendliness. Furthermore, each of the biomass-based epoxy resin compositions from the examples exhibits a polymer gel time of 20 minutes or less, thus demonstrating excellent processability. Additionally, each of the biomass-based epoxy resin compositions from the examples exhibits a polymer Tg of 60°C or more, thus demonstrating excellent heat resistance.

[0092] It was observed that the mixed viscosity in Examples 1 to 5 and 8 was considerably lower compared to the comparison examples 2 and 3, in which the monomer derived from biomass (C) was not added. In particular, in Examples 3 and 4, the mixed viscosity, due to the addition of the monomer derived from biomass (C) in an amount of 50 wt.% or more, was equivalent to that of an acid anhydride-curing epoxy resin composition, as shown in Example 1, which is useful as a potting compound.

[0093] It was also observed that the mixed viscosity in Example 7 was considerably lower compared to Comparison Example 6, in which the monomer obtained from biomass component (C) was not added.

[0094] These results show that the processability can be significantly improved when the monomer derived from biomass (C) is included. It is also shown that it is possible to further improve the processability by increasing the percentage of the monomer derived from biomass (C).

[0095] Each of Examples 1 to 4 showed a broad tan-δ peak, indicating that the epoxy-cured product and the polymer were mixed in a partially compatible state. In contrast, Example 5 showed two tan-δ peaks, indicating that phase separation of the epoxy-cured product and the polymer occurred. It is conceivable that if the polymer gel time is short, as in Example 5, the epoxy-cured product and the polymer do not mix in a sufficiently compatible state and instead undergo partial phase separation at the time a cured product of the biomass-epoxy resin composition is formed.

[0096] The tan-δ peak temperature in Examples 1 to 4 indicates that with increasing amounts of IBOMA, which has a Tg of 180 °C for the polymer alone, the Tg of the cured biomass-epoxy resin composition becomes higher. In Examples 1 and 2, the tan-δ peak temperature was between the Tg of the epoxy-cured product and the Tg of the polymer. It is assumed that the epoxy-cured product and the polymer were mixed in a partially compatible state, and consequently, the Tg of the biomass-epoxy resin composition as a whole was between the Tg of the epoxy-cured product and the Tg of the polymer.

[0097] However, in examples 3 and 4, the tan-δ peak temperature was higher than the Tg of the polymer alone. It is assumed that the molecular chain of the cured epoxy resin and the molecular chain of the polymer were physically intertwined and held together, resulting in a higher Tg than that of the polymer alone and thus increased heat resistance.

[0098] When the epoxy-cured product and the polymer underwent partial phase separation, as in Example 5, the lower tan-δ peak temperature among the two tan-δ peak temperatures corresponded to the tan-δ peak temperature in Comparative Example 2, in which the biomass-epoxy resin composition did not contain the monomer derived from biomass (C). However, it was observed that even when the epoxy-cured product and the polymer underwent partial phase separation, the processability and heat resistance could still be improved when the monomer derived from biomass (C) was included.

[0099] These results show that when the monomer obtained from biomass (C) is included, heat resistance can be improved.

[0100] It was observed that in Example 6, although the Tg of the polymer was relatively low, the mixed viscosity was lower than that in Comparative Example 3, which did not contain the monomer obtained from biomass (C), and thus the processability was improved.

[0101] Examples 1 and 8 have the same percentage content of the monomer component. In Example 1, only IBOMA was used, with a Tg of the polymer alone of 180 °C, while in Example 8, both IBOMA and GM were used in equal amounts, with a Tg of the polymer alone of 46 °C. Although the Tg of the polymer alone differs significantly for IBOMA from that for GM, the tan-δ peak temperature in Example 7 was significantly higher than the tan-δ peak temperature in Example 1. It is hypothesized that, because the biomass epoxy resin composition contained the compatible monomer (F), the epoxy-cured product and the polymer were not only physically intertwined via their molecular chains but also partially chemically bonded, thereby improving the compatibility between the epoxy-cured product and the polymer and enhancing the heat resistance.

[0102] These results show that when the compatible monomer (F) is included, heat resistance can be improved.

[0103] Comparison example 1 has poor environmental friendliness, as it contains neither the hardener obtained from biomass (B) nor the monomer obtained from biomass (C).

[0104] Comparative examples 2 and 3 show poor processability compared to examples 1 to 6, as the monomer obtained from biomass (C) is missing.

[0105] Comparative example 4 exhibits poor heat resistance, as the Tg of the polymer is less than 60 °C.

[0106] In comparative example 5, the fact that the polymer's gel time at 100 °C exceeded 20 minutes led to accelerated volatilization of the biomass (C)-derived monomer and a reduction in its degree of polymerization. It is conceivable that a polymer with a low molecular weight was formed and its Tg was less than 60 °C, thus impairing its heat resistance.

[0107] It is understood that the embodiments and examples disclosed in this document are given for illustrative purposes in every respect and not for limitation. It is intended that the scope of this disclosure is defined by the claims and not by the preceding description, and includes all modifications and variations that are equivalent to the claims in meaning and scope. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2009-263549 [0004, 0005] JP 2013-181040 [0004, 0005] JP 2016-520677

[0005] Cited non-patent literature

[0000] RE105U, manufactured by Toki Sangyo Co., Ltd.

[0088] < / ergebnisse> < / testbedingungen> < / bewertungsverfahren> < / testbedingungen>

Claims

[1] Biomass epoxy resin composition comprising: an epoxy resin; a hardener derived from biomass; a monomer derived from biomass; and a polymerization initiator, wherein a gel time at 100 °C or less of a polymer obtained from the monomer is 20 minutes or less and a glass transition temperature of the polymer obtained from the monomer is 60 °C or more. [2] The biomass epoxy resin composition according to claim 1, wherein a percentage content of radiocarbon relative to the 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 includes at least one selected from the group consisting of 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 includes at least one selected from the group consisting of 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 the group consisting of hydroperoxides and ketone peroxides, and a metal salt. [6] The biomass epoxy resin composition according to any one of claims 1 to 5, further comprising an inorganic filler. [7] Biomass epoxy resin composition according to any one of claims 1 to 6, further comprising a compatible monomer. [8] The biomass epoxy resin composition of claim 7, wherein the compatible monomer is glycidyl methacrylate.