WO2016063779A1 - Epoxy resin and hardener for epoxy resin - Google Patents

Epoxy resin and hardener for epoxy resin Download PDF

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Publication number
WO2016063779A1
WO2016063779A1 PCT/JP2015/079079 JP2015079079W WO2016063779A1 WO 2016063779 A1 WO2016063779 A1 WO 2016063779A1 JP 2015079079 W JP2015079079 W JP 2015079079W WO 2016063779 A1 WO2016063779 A1 WO 2016063779A1
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Prior art keywords
epoxy resin
lignin
carboxylic acid
modified
mass
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PCT/JP2015/079079
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French (fr)
Japanese (ja)
Inventor
康典 大橋
霖 周
麻衣子 山本
高橋　昭雄
俊幸 大山
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ハリマ化成株式会社
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Publication of WO2016063779A1 publication Critical patent/WO2016063779A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/02—Polycondensates containing more than one epoxy group per molecule
    • C08G59/04—Polycondensates containing more than one epoxy group per molecule of polyhydroxy compounds with epihalohydrins or precursors thereof
    • C08G59/06—Polycondensates containing more than one epoxy group per molecule of polyhydroxy compounds with epihalohydrins or precursors thereof of polyhydric phenols
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
    • C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
    • C08G59/62—Alcohols or phenols

Definitions

  • the present invention relates to an epoxy resin and an epoxy resin curing agent.
  • the cured epoxy resin is usually produced by blending an epoxy resin and an epoxy resin curing agent and curing the mixture, for example, an electrical / electronic component such as a semiconductor sealing material, for example, a paint or an adhesive. It is widely used in various industrial fields.
  • an epoxy resin obtained by reacting a gramineous plant lignin recovered from a pulp waste liquor by an alkali digestion method with epichlorohydrin has been proposed.
  • the use of plant lignin as an epoxy resin curing agent has also been proposed (see Patent Document 2).
  • an epoxy resin it can be obtained by further reacting epichlorohydrin with a lignin phenol resin obtained by reacting a grass lignin recovered from pulp waste liquor by an alkali digestion method and a phenol under an acid catalyst.
  • An epoxy resin has been proposed, and the use of the above lignin phenol resin as an epoxy resin curing agent has also been proposed (see Patent Document 3).
  • the epoxy resin composition described in Patent Document 1 has a disadvantage that the fluidity is relatively low and the handling property is inferior because the molecular weight of lignophenol as a raw material component is relatively large.
  • the resulting epoxy resin cured product may not have sufficient heat resistance.
  • an object of the present invention is to provide an epoxy resin and an epoxy resin curing agent capable of obtaining an epoxy resin cured product having excellent handleability and heat resistance.
  • the epoxy resin of the present invention is characterized in that it is obtained by reacting at least lignin modified with carboxylic acid and epichlorohydrin.
  • the lignin modified with the carboxylic acid is phenol-modified.
  • the lignin modified with the carboxylic acid is extracted with an organic solvent.
  • the epoxy resin curing agent of the present invention is characterized by containing lignin modified with carboxylic acid.
  • the lignin modified with the carboxylic acid is phenol-modified.
  • the lignin modified with the carboxylic acid is extracted with an organic solvent.
  • the epoxy resin and the epoxy resin curing agent of the present invention are obtained using lignin modified with carboxylic acid, the handling property is excellent and the heat resistance of the cured epoxy resin product can be improved.
  • Epoxy resin of the present invention can be obtained by reacting lignin modified with carboxylic acid (hereinafter sometimes referred to as carboxylic acid-modified lignin) and epichlorohydrin.
  • examples of the carboxylic acid include a carboxylic acid having one carboxy group (hereinafter, sometimes referred to as a monofunctional carboxylic acid).
  • Functional carboxylic acid unsaturated aliphatic monofunctional carboxylic acid, aromatic monofunctional carboxylic acid and the like can be mentioned.
  • saturated aliphatic monofunctional carboxylic acid examples include acetic acid, propionic acid, butyric acid, lauric acid and the like.
  • Examples of the unsaturated aliphatic monofunctional carboxylic acid include acrylic acid, methacrylic acid, and linoleic acid.
  • aromatic monofunctional carboxylic acid examples include benzoic acid, 2-phenoxybenzoic acid, and 4-methylbenzoic acid.
  • carboxylic acids can be used alone or in combination of two or more.
  • the carboxylic acid is preferably a saturated aliphatic monofunctional carboxylic acid, and more preferably acetic acid. If the carboxylic acid is used, a carboxylic acid-modified lignin can be easily obtained, and the carboxylic acid-modified lignin obtained has a relatively high solubility in an organic solvent and has a melting temperature as described later. Since it is relatively low temperature (about 100 to 200 ° C.), it is excellent in handleability.
  • Lignin is a high molecular phenolic compound having a basic skeleton such as guaiacyl lignin (G-type), syringyl lignin (S-type), p-hydroxyphenyl lignin (H-type), and is included in all plants. .
  • G-type guaiacyl lignin
  • S-type syringyl lignin
  • H-type p-hydroxyphenyl lignin
  • Such natural lignin is industrially extracted, for example, soda lignin contained in waste liquid (black liquor) discharged when producing pulp from plant raw materials by soda method, sulfite method, kraft method, etc. , Sulfite lignin, craft lignin and the like are known.
  • lignin examples include woody plant-derived lignin and herbaceous plant-derived lignin.
  • woody plant-derived lignin examples include coniferous lignin contained in conifers (eg, cedar), for example, broadleaf lignin contained in broadleaf trees. Such woody plant-derived lignin does not contain lignin having H-type basic skeleton, for example, conifer lignin has G-type basic skeleton, and hardwood lignin has G-type and S-type basic skeleton. Yes.
  • herbaceous plant-derived lignin examples include rice-based lignin contained in grass family plants (wheat straw, rice straw, corn, bamboo, etc.). Such herbaceous plant-derived lignin has all of H-type, G-type and S-type as the basic skeleton.
  • lignins can be used alone or in combination of two or more.
  • the lignin is preferably a herbaceous plant-derived lignin, more preferably a herbaceous plant-derived lignin derived from corn stover (corn core, stem, leaf, etc.).
  • lignin from the viewpoint of reactivity, it is preferable to contain an H-type basic skeleton in a proportion of 9% by mass or more, more preferably 14% by mass or more.
  • the production method of the carboxylic acid-modified lignin is not particularly limited, and can conform to a known method.
  • plant materials for example, conifers, hardwoods, gramineous plants, etc.
  • carboxylic acid preferably acetic acid
  • the cooking method is not particularly limited.
  • a plant material that is a raw material for lignin is mixed with a carboxylic acid and an inorganic acid (for example, hydrochloric acid, sulfuric acid, etc.) and reacted.
  • an inorganic acid for example, hydrochloric acid, sulfuric acid, etc.
  • the mixing ratio of the carboxylic acid is such that the carboxylic acid (100% conversion) is, for example, 500 parts by mass or more, preferably 900 parts by mass or more, for example, 30000 with respect to 100 parts by mass of the plant material that is the raw material for lignin. It is 1 part by mass or less, preferably 15000 parts by mass or less.
  • the blending ratio of the inorganic acid is, for example, 0.01 parts by mass or more, preferably 0.05 parts by mass or more with respect to 100 parts by mass of the plant material that is the raw material for lignin. For example, it is 10 parts by mass or less, preferably 5 parts by mass or less.
  • the reaction temperature is, for example, 30 ° C. or higher, preferably 50 ° C. or higher, for example, 400 ° C. or lower, preferably 250 ° C. or lower.
  • the reaction time is, for example, 0.5 hours or more, preferably 1 hour or more, for example, 20 hours or less, preferably 10 hours or less.
  • the pulp is separated by a known separation method such as filtration, and the filtrate (pulp waste liquid) is recovered.
  • the unreacted carboxylic acid is known using, for example, a rotary evaporator, vacuum distillation or the like. It is removed (distilled off) by the method. Thereafter, a large excess of water is added to precipitate the carboxylic acid-modified lignin, followed by filtration to recover the carboxylic acid-modified lignin as a solid content.
  • carboxylic acid-modified lignin is obtained by reacting lignin not modified with carboxylic acid (hereinafter, unmodified lignin) with carboxylic acid. You can also.
  • the native lignin is preferably powdered native lignin.
  • the average particle size of the powdered unmodified lignin is, for example, 0.1 ⁇ m or more, preferably 5 ⁇ m or more, for example, 1000 ⁇ m or less, preferably 500 ⁇ m or less.
  • the average particle diameter is in the above range, aggregation of the unmodified lignin can be suppressed and the unmodified lignin can be favorably dispersed in the carboxylic acid.
  • the powdered unmodified lignin can be obtained by drying and pulverizing the lump unmodified lignin by a known method, or a commercially available product can be used.
  • unmodified lignin and carboxylic acid for example, unmodified lignin, carboxylic acid and inorganic acid (for example, hydrochloric acid, sulfuric acid, etc.) are mixed and reacted.
  • unmodified lignin, carboxylic acid and inorganic acid for example, hydrochloric acid, sulfuric acid, etc.
  • the mixing ratio of the carboxylic acid is, for example, 300 parts by mass or more, preferably 500 parts by mass or more, for example, 15000 parts by mass or less, based on 100 parts by mass of the unmodified lignin. Preferably, it is 10000 parts by mass or less.
  • the blending ratio of the inorganic acid is such that the inorganic acid (100% conversion) is, for example, 0.01 parts by mass or more, preferably 0.05 parts by mass or more with respect to 100 parts by mass of the unmodified lignin. 10 parts by mass or less, preferably 5 parts by mass or less.
  • reaction temperature is, for example, 30 ° C. or higher, preferably 50 ° C. or higher, for example, 400 ° C. or lower, preferably 250 ° C. or lower.
  • reaction time is, for example, 0.5 hours or more, preferably 1 hour or more, for example, 20 hours or less, preferably 10 hours or less.
  • Such carboxylic acid-modified lignin is excellent in handleability.
  • lignin that has not been modified with carboxylic acid has relatively low solubility in organic solvents and does not melt, so that it may be inferior in handleability depending on the application.
  • lignin modified with a carboxylic acid as described above is a polar organic solvent (for example, acetone, methanol, phenol, tetrahydrofuran, acetonitrile, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, Dimethyl sulfoxide, hexamethylphosphonilamide, etc.) are relatively high in solubility, and the melting temperature is relatively low (about 100 to 200 ° C.), so that the handling property is excellent.
  • a polar organic solvent for example, acetone, methanol, phenol, tetrahydrofuran, acetonitrile, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, Dimethyl sulfoxide, hexamethylphosphonilamide, etc.
  • the carboxylic acid-modified lignin is preferably extracted from the product (crude product) obtained by the above-described method with an organic solvent.
  • organic solvent examples include the polar organic solvents described above, and preferably acetone.
  • the carboxylic acid-modified lignin By extracting the carboxylic acid-modified lignin with an organic solvent, the carboxylic acid-modified lignin can be purified, and the heat resistance of the cured epoxy resin (described later) can be improved.
  • the extraction method is not particularly limited, and a known method is employed.
  • the extraction rate of the carboxylic acid-modified lignin is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, for example, 90% by mass or less, preferably 80% by mass or less. is there.
  • the carboxylic acid-modified lignin is preferably phenol-modified.
  • carboxylic acid-modified lignin for example, carboxylic acid-modified lignin (carboxylic acid-modified lignin that has not been phenol-modified) and phenols are reacted in the presence of an acid catalyst.
  • phenols examples include phenol, cresol (o-cresol, m-cresol, p-cresol, etc.), resorcinol and the like.
  • phenols can be used alone or in combination of two or more.
  • the phenols are preferably cresol, more preferably p-cresol, from the viewpoint of performance improvement.
  • the blending ratio of the phenols is, for example, 100 parts by mass or more, preferably 300 parts by mass or more, for example, 5000 parts by mass or less, preferably 100 parts by mass or less, based on 100 parts by mass of the carboxylic acid-modified lignin not modified with phenol. It is 3000 parts by mass or less.
  • the acid catalyst is not particularly limited, and may be a known acid catalyst. Specific examples include strong inorganic acids such as sulfuric acid, nitric acid, and hydrochloric acid.
  • These acid catalysts can be used alone or in combination of two or more.
  • the acid catalyst is preferably sulfuric acid from the viewpoint of low cost and improved performance.
  • the mixing ratio of the acid catalyst is, for example, 1 part by mass or more, preferably 5 parts by mass or more, for example, 20 parts by mass or less, preferably 100 parts by mass with respect to 100 parts by mass of the carboxylic acid-modified lignin not modified with phenol. 15 parts by mass or less.
  • formaldehyde can be used in combination in the reaction of carboxylic acid-modified lignin and phenols.
  • formaldehyde When formaldehyde is used, formaldehyde is copolymerized with carboxylic acid-modified lignin and phenols, and formaldehyde becomes a methylene group by dehydration condensation, so that phenol-modified carboxylic acid-modified lignin (carboxylic acid-modified lignin-phenol resin) In this method, a phenol group is bonded through a methylene group.
  • the blending ratio is 2 mol or less, preferably 1 mol or less with respect to 1 mol of phenols.
  • a solvent may be added if necessary.
  • the solvent include N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphonamide, and preferably N, N-dimethylformamide.
  • the blending amount is, for example, 25 parts by mass or more, preferably 40 parts by mass or more, for example, 100 parts by mass or less, preferably 60 parts by mass with respect to 100 parts by mass of the carboxylic acid-modified lignin. It is below mass parts.
  • each component may be blended in the above ratio and heated.
  • the reaction temperature is, for example, 100 ° C. or more, preferably 110 ° C. or more, for example, 200 ° C. or less, preferably 150 ° C. or less.
  • the reaction time is, for example, 30 minutes or longer, for example, 3 hours or shorter.
  • phenol-modified carboxylic acid-modified lignin phenol-modified carboxylic acid-modified lignin, carboxylic acid-modified lignin-phenol resin
  • carboxylic acid-modified lignin-phenol resin phenol-modified carboxylic acid-modified lignin, carboxylic acid-modified lignin-phenol resin
  • the acid catalyst can be neutralized by adding an alkali if necessary.
  • unreacted components can be removed and recovered by a known method such as filtration or distillation.
  • distillation conditions in particular in the case of distilling are not restrict
  • the recovered unreacted components can be directly used for the next production.
  • a phenol-modified carboxylic acid-modified lignin is obtained as a solution (for example, when an alkaline aqueous solution is added), the solution is dropped into an organic solvent such as hexane to add phenol.
  • Carboxylic acid-modified lignin can be recovered as a precipitate.
  • the phenol-modified carboxylic acid-modified lignin recovered as a precipitate can be dissolved in an organic solvent or the like and recovered as a precipitate again to purify the phenol-modified carboxylic acid-modified lignin.
  • the phenol-modified carboxylic acid-modified lignin (carboxylic acid-modified lignin-phenol resin) can be washed.
  • the washing method is not particularly limited, and for example, water may be added to phenol-modified carboxylic acid-modified lignin (carboxylic acid-modified lignin-phenol resin) and stirred. By such washing, impurities and salts generated by the neutralization can be removed.
  • the mixing ratio of carboxylic acid-modified lignin and epichlorohydrin is an excess amount of epichlorohydrin with respect to 100 parts by mass of carboxylic acid-modified lignin. Specifically, for example, 150 parts by mass or more, preferably 250 parts by mass or more, for example, 2000 parts by mass or less, preferably 1000 parts by mass or less.
  • the reaction temperature is, for example, 80 ° C. or higher, preferably 90 ° C. or higher, for example, 120 ° C. or lower, preferably 110 ° C. or lower.
  • the reaction time is, for example, 2 hours or more, preferably 2.5 hours or more, for example, 4 hours or less, preferably 3.5 hours or less.
  • a glycidyl ether group can be bonded to the carboxylic acid-modified lignin to obtain an epoxy resin.
  • epichlorohydrin is added to the carboxylic acid-modified lignin in the above ratio in the presence of a known phase transfer catalyst (for example, a quaternary ammonium salt such as tetramethylammonium (TBAC)).
  • a known phase transfer catalyst for example, a quaternary ammonium salt such as tetramethylammonium (TBAC)
  • TBAC tetramethylammonium
  • an epoxy resin can be obtained by combining carboxylic acid-modified lignin and epichlorohydrin by a two-step reaction in which an alkaline solution (such as an aqueous sodium hydroxide solution) is dropped to close the ring.
  • the reaction temperature in the first stage reaction is, for example, 60 ° C. or higher, preferably 75 ° C. or higher, for example, 90 ° C. or lower, preferably 85 ° C. or lower.
  • the reaction time is, for example, 6 hours or more, preferably 7 hours or more, for example, 10 hours or less, preferably 9 hours or less.
  • the reaction temperature in the second stage reaction is, for example, 20 ° C. or more, preferably 35 ° C. or more, for example, 50 ° C. or less, preferably 45 ° C. or less.
  • the reaction time is, for example, 10 hours or more, preferably 14 hours or more, for example, 20 hours or less, preferably 16 hours or less.
  • the binding ratio of carboxylic acid-modified lignin and epichlorohydrin is usually 20 to 35 parts by mass of epichlorohydrin with respect to 100 parts by mass of carboxylic acid-modified lignin. is there.
  • the content of the carboxylic acid-modified lignin in the epoxy resin thus obtained is, for example, 70 parts by mass or more, preferably 75 parts by mass or more, with respect to 100 parts by mass of the total amount of the epoxy resin. 85 parts by mass or less.
  • Epoxy resin curing agent contains a carboxylic acid-modified lignin.
  • Examples of the carboxylic acid-modified lignin include the above-described carboxylic acid-modified lignin.
  • carboxylic acid-modified lignin is preferably extracted with an organic solvent.
  • the carboxylic acid-modified lignin By extracting the carboxylic acid-modified lignin with an organic solvent, the carboxylic acid-modified lignin can be purified, and the heat resistance of the cured epoxy resin (described later) can be improved.
  • the carboxylic acid-modified lignin is preferably used after being phenol-modified.
  • the heat resistance of the cured epoxy resin (described later) can be further improved.
  • Epoxy resin composition contains a main agent composed of an epoxy resin and an epoxy resin curing agent.
  • Examples of the epoxy resin include the above-described epoxy resin of the present invention, and examples of the epoxy resin curing agent include the above-described epoxy resin curing agent of the present invention.
  • epoxy resin curing agents include, for example, aliphatic amines, aromatic amines, polyphenol compounds, novolak resins, acid anhydrides, and the like.
  • An epoxy resin curing agent can be used.
  • epoxy resin curing agent of the present invention When the above-described epoxy resin curing agent of the present invention is used as the epoxy resin curing agent, a known epoxy resin such as a bisphenol type epoxy resin or a novolac type epoxy resin can be used as the epoxy resin. .
  • epoxy resin the above-described epoxy resin of the present invention and a known epoxy resin can be used in an appropriate ratio
  • epoxy resin curing agent the above-described epoxy resin curing agent of the present invention
  • curing agent can also be used together in a suitable ratio.
  • the above-described epoxy resin of the present invention is used as the epoxy resin
  • the above-described epoxy resin curing agent of the present invention is used as the epoxy resin curing agent
  • the amine equivalent and / or phenolic hydroxyl group equivalent of the epoxy resin curing agent and the epoxy equivalent of the main agent are approximately equivalent to ⁇ 20% equivalent. It mix
  • the blending method is not particularly limited.
  • the main agent (epoxy resin) and the epoxy resin curing agent are dissolved in a common solvent (for example, tetrahydrofuran, acetone, methyl ethyl ketone, methanol, acetonitrile, etc.), and if necessary.
  • a common solvent for example, tetrahydrofuran, acetone, methyl ethyl ketone, methanol, acetonitrile, etc.
  • curing agent it can heat as needed.
  • the heating temperature is, for example, 40 ° C. or higher, preferably 50 ° C. or higher, for example, 70 ° C. or lower, preferably 60 ° C. or lower.
  • a curing accelerator can be added to the epoxy resin composition at an appropriate timing.
  • curing accelerator examples include 2-ethyl-4-methylimidazole and derivatives thereof, 1-cyanoethyl-2-ethyl-4-methylimidazole and derivatives thereof, and tertiary amines such as benzyldimethylamine, triphenyl Examples include phosphine (TPP) derivatives (such as caribol salt) and known curing accelerators.
  • TPP phosphine
  • the blending ratio is, for example, 0.1 parts by mass or more, preferably 0.2 parts by mass or more with respect to 100 parts by mass of the total amount of the epoxy resin and the epoxy resin curing agent. For example, 3 parts by mass or less, preferably 2 parts by mass or less.
  • an epoxy resin composition uses lignin modified with a carboxylic acid in an epoxy resin and / or an epoxy resin curing agent, it is excellent in handleability and improves the heat resistance of a cured epoxy resin. Can be achieved. 4).
  • Cured epoxy resin The cured epoxy resin can be obtained by curing the epoxy resin composition.
  • Examples of the method of curing the epoxy resin composition include a method of injecting the epoxy resin composition into a known mold and heating, a method of vacuum hot press molding, and the like.
  • the epoxy resin may be heated in one step, or may be heated in two or more steps. Preferably, the epoxy resin is heated in two stages.
  • the heating temperature at the first stage is, for example, 140 ° C. or higher, preferably 145 ° C. or higher, for example, 160 ° C. or lower, preferably 155 ° C. or lower.
  • the first stage heating time is, for example, 1.5 hours or more, preferably 2 hours or more, for example, 3 hours or less, preferably 2.5 hours or less.
  • the heating temperature in the second stage is, for example, 170 ° C. or higher, preferably 175 ° C. or higher, for example, 190 ° C. or lower, preferably 185 ° C. or lower.
  • the heating time of the second stage is, for example, 2.5 hours or more, preferably 3 hours or more, for example, 4 hours or less, preferably 3.5 hours or less.
  • such a cured epoxy resin is excellent in mechanical properties and electrical properties, and is obtained by using lignin modified with carboxylic acid, so it is compatible with carbon neutral and has an environmental impact. Can be reduced.
  • a cured epoxy resin is widely used in various industrial fields as an adhesive, a molding material, a structural material, a semiconductor encapsulant, an electronic material, and the like.
  • Production Example 2 (without extraction / with phenol modification) In the same manner as in Production Example 1, acetic acid-modified lignin was obtained as a solid content.
  • the mixture was cooled to a temperature of 100 ° C. or lower and neutralized by adding 45.3 parts by mass of a 20% aqueous sodium hydroxide solution. Subsequently, the insoluble part was removed by filtration, and then the obtained solution (filtrate) was dropped into 20 times volume of hexane to obtain a precipitate.
  • the obtained precipitate was collected by suction filtration and dissolved in the necessary minimum (about 100 parts by mass) of tetrahydrofuran (THF). Next, the obtained solution was added dropwise to 20 times volume of hexane in tetrahydrofuran to obtain a precipitate again.
  • THF tetrahydrofuran
  • the obtained precipitate was dried under the conditions of 60 ° C. and 40 mmHg for 15 hours to obtain a phenol-modified product of lignin acetate.
  • Production Example 3 (with extraction / no phenol modification) In the same manner as in Production Example 1, acetic acid-modified lignin was obtained as a solid content.
  • acetic acid-modified lignin was dissolved in an organic solvent (acetone), and insoluble matters were removed by filtration. Thereafter, an organic solvent solution of acetic acid-modified lignin was dried to obtain acetic acid-modified lignin (an extract with an organic solvent).
  • Production Example 4 (with extraction / with phenol modification) The acetic acid-modified lignin was phenol-modified in the same manner as in Production Example 2 except that the acetic acid-modified lignin obtained in Production Example 3 (extract with an organic solvent) was used. As a result, a phenol-modified product of lignin acetate (extract with an organic solvent) was obtained.
  • Comparative production example 1 (no extraction / no phenol modification) After neutralizing the straw straw alkaline digested pulp waste liquor (black liquor), it was filtered to obtain unmodified lignin as a solid content.
  • the unmodified lignin was phenol-modified in the same manner as in Production Example 2. As a result, a phenol-modified product of unmodified lignin (lignin not modified with carboxylic acid) was obtained.
  • Comparative Production Example 3 (with extraction / no phenol modification) In the same manner as in Comparative Production Example 1, unmodified lignin was obtained as a solid content.
  • the obtained unmodified lignin was dissolved in an organic solvent (methanol), and insoluble matters were removed by filtration. Thereafter, an organic solvent solution of native lignin was dried to obtain native lignin (an extract with an organic solvent).
  • Comparative Production Example 4 (with extraction / with phenol modification) The unmodified lignin was phenol-modified in the same manner as in Production Example 2, except that the unmodified lignin obtained in Comparative Production Example 3 (extract with an organic solvent) was used. As a result, a phenol-modified product of unmodified lignin (extract with an organic solvent) was obtained.
  • the obtained solution was transferred to a separatory funnel and washed five times with 100 mL of ion exchange water, and then anhydrous magnesium sulfate was added to remove moisture.
  • the epoxy equivalent (EEW) of the obtained epoxy resin was 280.
  • the epoxy equivalent (EEW) was measured by the following method.
  • the obtained epoxy resin (epoxidized lignin) was dissolved in deuterated chloroform, 1,1 ′, 2,2′-tetrachloroethane (TCE) as a reference material was added, and then 1 H-NMR The spectrum was measured, and the epoxy equivalent was calculated from the integrated intensity ratio of each peak according to the following formula (hereinafter the same).
  • TCE Integral intensity of 1,1 ′, 2,2′-tetrachloroethane
  • I epoxy Integral intensity of epoxy group
  • W epoxy resin Mass of epoxy resin (epoxidized lignin)
  • W TCE 1,1 ′, Mass of 2,2′-tetrachloroethane (TCE)
  • M TCE Molecular weight of 1,1 ′, 2,2′-tetrachloroethane (TCE) Comparative Example 1
  • An epoxy resin was obtained in the same manner as in Example 1 except that the unmodified lignin (extract with an organic solvent) obtained in Comparative Production Example 3 was used. The epoxy equivalent of the obtained epoxy resin was 290.
  • Evaluation 1 In order to examine the performance of each epoxy resin, an epoxy resin and an epoxy resin curing agent were blended and cured.
  • the epoxy resin curing agent a commercially available novolak resin (Phenolite TD-2131, manufactured by DIC Corporation) was used.
  • an epoxy resin and an epoxy resin curing agent are prepared so that the epoxy equivalent of the epoxy resin and the amine equivalent and / or phenolic hydroxyl group equivalent of the epoxy resin curing agent are approximately equal. Then, they are dissolved in tetrahydrofuran, and then a curing accelerator (1-cyanoethyl-2-ethyl-4-methylimidazole) is added in an amount of 0.5 parts by mass with respect to 100 parts by mass of the total amount of the epoxy resin and the epoxy resin curing agent. The varnish was obtained by adding so that it might become. Subsequently, the obtained varnish was cast on a film, dried at 60 ° C. for 2 hours, and tetrahydrofuran was removed to obtain an epoxy resin composition.
  • a curing accelerator (1-cyanoethyl-2-ethyl-4-methylimidazole
  • the product was filled in a Teflon (registered trademark) mold, heated in a vacuum press at 150 ° C. for 2 hours, and then heated at 180 ° C. for 3 hours to be cured.
  • the epoxy resin composition was cured after being melted and exhibited fluidity, and then cured.
  • the obtained cured epoxy resin was evaluated by the following method. The results are shown in Table 1.
  • DVA dynamic viscoelasticity analysis
  • the size of the test piece was 10 mm ⁇ 40 mm ⁇ 2 mm.
  • the measurement mode was a three-point bending mode.
  • the measurement conditions were an air condition, a temperature range of ⁇ 100 ° C. to 300 ° C., a temperature increase rate of 5 ° C./min, and a frequency of 1 Hz.
  • the ⁇ relaxation peak temperature of the tan ⁇ curve thus obtained was defined as the glass transition temperature (Tg).
  • Example 3 The phenol-modified product of acetic acid-modified lignin (extracted with an organic solvent) obtained in Production Example 4 was used as an epoxy resin curing agent.
  • Comparative Example 2 The phenol-modified product of unmodified lignin obtained in Comparative Production Example 2 was used as an epoxy resin curing agent.
  • Comparative Example 3 The phenol-modified product of unmodified lignin (extracted with an organic solvent) obtained in Comparative Production Example 4 was used as an epoxy resin curing agent.
  • Evaluation 2 In order to examine the performance of each epoxy resin curing agent, an epoxy resin and an epoxy resin curing agent were blended and cured.
  • the epoxy resin a commercially available bisphenol A type epoxy resin (trade name JER 828, manufactured by Mitsubishi Chemical Corporation) was used.
  • an epoxy resin and an epoxy resin curing agent are prepared so that the epoxy equivalent of the epoxy resin and the amine equivalent and / or phenolic hydroxyl group equivalent of the epoxy resin curing agent are approximately equal. Then, they are dissolved in tetrahydrofuran, and then a curing accelerator (1-cyanoethyl-2-ethyl-4-methylimidazole) is added in an amount of 0.5 parts by mass with respect to 100 parts by mass of the total amount of the epoxy resin and the epoxy resin curing agent. The varnish was obtained by adding so that it might become. Subsequently, the obtained varnish was cast on a film, dried at 60 ° C. for 2 hours, and tetrahydrofuran was removed to obtain an epoxy resin composition.
  • a curing accelerator (1-cyanoethyl-2-ethyl-4-methylimidazole
  • the product was filled in a Teflon (registered trademark) mold, heated in a vacuum press at 150 ° C. for 2 hours, and then heated at 180 ° C. for 3 hours to be cured.
  • the epoxy resin composition was cured after being melted and exhibited fluidity, and then cured.
  • the epoxy resin and the epoxy resin curing agent obtained using lignin modified with acetic acid have a relatively high glass transition temperature and excellent heat resistance. It was confirmed that a cured epoxy resin was obtained.
  • thermogravimetric analysis TGA-50 manufactured by Shimadzu Corporation was used. More specifically, a sample made into a powder form with a gold file is weighed into a platinum cell so that the weight is 3 to 4 mg, and the temperature range is from room temperature to 800 ° C., the heating rate is 10 ° C./min, and the nitrogen stream ( 20 mL / min). Based on the weight at 40 ° C., the temperature when the weight decreased by 5% was defined as the 5% weight decrease temperature (T d5 ), and the temperature when decreased by 10% was defined as the 10% weight decrease temperature (T d10 ).
  • the epoxy resin obtained by using lignin modified with acetic acid has a relatively high 5% weight reduction temperature and 10% weight reduction temperature, and is excellent in heat resistance. It was confirmed that a cured product was obtained.
  • the epoxy resin cured product obtained by using the epoxy resin and the epoxy resin curing agent of the present invention is widely used in various electronic fields such as electrical and electronic parts such as semiconductor sealing materials, and paints and adhesives.

Abstract

An epoxy resin and a hardener for epoxy resins, the epoxy resin being characterizing by being obtained by at least reacting epichlorohydrin with lignin modified with a carboxylic acid.

Description

エポキシ樹脂およびエポキシ樹脂硬化剤Epoxy resin and epoxy resin curing agent
　本発明は、エポキシ樹脂およびエポキシ樹脂硬化剤に関する。 The present invention relates to an epoxy resin and an epoxy resin curing agent.
　エポキシ樹脂硬化物は、通常、エポキシ樹脂と、エポキシ樹脂硬化剤とを配合して、硬化させることにより製造されており、例えば、半導体封止材などの電気電子部品や、例えば、塗料、接着剤などの各種工業分野において、広く用いられている。 The cured epoxy resin is usually produced by blending an epoxy resin and an epoxy resin curing agent and curing the mixture, for example, an electrical / electronic component such as a semiconductor sealing material, for example, a paint or an adhesive. It is widely used in various industrial fields.
　近年、このようなエポキシ樹脂およびエポキシ樹脂硬化剤を含むエポキシ樹脂組成物としては、環境破壊を抑制する観点から、カーボンニュートラルに対応する植物由来原料を用いることが検討されている。具体的には、エポキシ樹脂とリグノフェノールとを主成分として含むエポキシ樹脂組成物が提案されており、また、エポキシ樹脂として、エポキシ化リグノフェノールを用いることも、提案されている（特許文献１参照）。 In recent years, as an epoxy resin composition containing such an epoxy resin and an epoxy resin curing agent, use of plant-derived materials corresponding to carbon neutral has been studied from the viewpoint of suppressing environmental destruction. Specifically, an epoxy resin composition containing an epoxy resin and lignophenol as main components has been proposed, and the use of epoxidized lignophenol as an epoxy resin has also been proposed (see Patent Document 1). ).
　また、エポキシ樹脂としては、上記のほか、アルカリ蒸解法によるパルプ廃液から回収したイネ科植物リグニンに、エピクロロヒドリンを反応させて得られるエポキシ樹脂が提案されており、また、上記のイネ科植物リグニンを、エポキシ樹脂硬化剤として用いることも、提案されている（特許文献２参照）。 In addition to the above, as an epoxy resin, an epoxy resin obtained by reacting a gramineous plant lignin recovered from a pulp waste liquor by an alkali digestion method with epichlorohydrin has been proposed. The use of plant lignin as an epoxy resin curing agent has also been proposed (see Patent Document 2).
　また、エポキシ樹脂としては、さらに、アルカリ蒸解法によるパルプ廃液から回収したイネ科植物リグニンとフェノール類とを酸触媒下で反応させてなるリグニンフェノール樹脂に、エピクロロヒドリンを反応させて得られるエポキシ樹脂が提案されており、また、上記のリグニンフェノール樹脂を、エポキシ樹脂硬化剤として用いることも、提案されている（特許文献３参照）。 Moreover, as an epoxy resin, it can be obtained by further reacting epichlorohydrin with a lignin phenol resin obtained by reacting a grass lignin recovered from pulp waste liquor by an alkali digestion method and a phenol under an acid catalyst. An epoxy resin has been proposed, and the use of the above lignin phenol resin as an epoxy resin curing agent has also been proposed (see Patent Document 3).
特開２００９－２９２８８４号公報JP 2009-29284 A 特開２０１１－１４４３４０号公報JP 2011-144340 A 特開２０１１－９９０８３号公報JP 2011-99083 A
　しかるに、特許文献１に記載のエポキシ樹脂組成物は、原料成分であるリグノフェノールの分子量が比較的大きいため、流動性が比較的低く、取扱性に劣るという不具合がある。 However, the epoxy resin composition described in Patent Document 1 has a disadvantage that the fluidity is relatively low and the handling property is inferior because the molecular weight of lignophenol as a raw material component is relatively large.
　また、特許文献２および特許文献３に記載のエポキシ樹脂およびエポキシ樹脂硬化剤を用いる場合、得られるエポキシ樹脂硬化物の耐熱性が、十分ではない場合がある。 In addition, when the epoxy resin and the epoxy resin curing agent described in Patent Document 2 and Patent Document 3 are used, the resulting epoxy resin cured product may not have sufficient heat resistance.
　そこで、本発明の目的は、取扱性および耐熱性に優れるエポキシ樹脂硬化物を得ることができるエポキシ樹脂およびエポキシ樹脂硬化剤を提供することにある。 Therefore, an object of the present invention is to provide an epoxy resin and an epoxy resin curing agent capable of obtaining an epoxy resin cured product having excellent handleability and heat resistance.
　本発明のエポキシ樹脂は、カルボン酸により変性されたリグニンと、エピクロロヒドリンとを少なくとも反応させることにより得られることを特徴としている。 The epoxy resin of the present invention is characterized in that it is obtained by reacting at least lignin modified with carboxylic acid and epichlorohydrin.
　また、本発明のエポキシ樹脂は、前記カルボン酸により変性された前記リグニンが、フェノール変性されていることが好適である。 In the epoxy resin of the present invention, it is preferable that the lignin modified with the carboxylic acid is phenol-modified.
　また、本発明のエポキシ樹脂は、前記カルボン酸により変性された前記リグニンが、有機溶媒により抽出されていることが好適である。 In the epoxy resin of the present invention, it is preferable that the lignin modified with the carboxylic acid is extracted with an organic solvent.
　また、本発明のエポキシ樹脂硬化剤は、カルボン酸により変性されたリグニンを含むことを特徴としている。 The epoxy resin curing agent of the present invention is characterized by containing lignin modified with carboxylic acid.
　また、本発明のエポキシ樹脂硬化剤は、前記カルボン酸により変性された前記リグニンが、フェノール変性されていることが好適である。 In the epoxy resin curing agent of the present invention, it is preferable that the lignin modified with the carboxylic acid is phenol-modified.
　また、本発明のエポキシ樹脂硬化剤は、前記カルボン酸により変性された前記リグニンが、有機溶媒により抽出されていることが好適である。 In the epoxy resin curing agent of the present invention, it is preferable that the lignin modified with the carboxylic acid is extracted with an organic solvent.
　本発明のエポキシ樹脂およびエポキシ樹脂硬化剤は、カルボン酸により変性されたリグニンを用いて得られるため、取扱性に優れ、また、エポキシ樹脂硬化物の耐熱性の向上を図ることができる。 Since the epoxy resin and the epoxy resin curing agent of the present invention are obtained using lignin modified with carboxylic acid, the handling property is excellent and the heat resistance of the cured epoxy resin product can be improved.
１．エポキシ樹脂
　本発明のエポキシ樹脂は、カルボン酸により変性されたリグニン（以下、カルボン酸変性リグニンと称する場合がある。）と、エピクロロヒドリンとを反応させることにより得ることができる。 1. Epoxy resin The epoxy resin of the present invention can be obtained by reacting lignin modified with carboxylic acid (hereinafter sometimes referred to as carboxylic acid-modified lignin) and epichlorohydrin.
　カルボン酸変性リグニンにおいて、カルボン酸としては、例えば、カルボキシ基を１つ有するカルボン酸（以下、単官能カルボン酸と称する場合がある。）が挙げられ、具体的には、例えば、飽和脂肪族単官能カルボン酸、不飽和脂肪族単官能カルボン酸、芳香族単官能カルボン酸などが挙げられる。 In the carboxylic acid-modified lignin, examples of the carboxylic acid include a carboxylic acid having one carboxy group (hereinafter, sometimes referred to as a monofunctional carboxylic acid). Functional carboxylic acid, unsaturated aliphatic monofunctional carboxylic acid, aromatic monofunctional carboxylic acid and the like can be mentioned.
　飽和脂肪族単官能カルボン酸としては、例えば、酢酸、プロピオン酸、酪酸、ラウリル酸などが挙げられる。 Examples of the saturated aliphatic monofunctional carboxylic acid include acetic acid, propionic acid, butyric acid, lauric acid and the like.
　不飽和脂肪族単官能カルボン酸としては、例えば、アクリル酸、メタクリル酸、リノール酸などが挙げられる。 Examples of the unsaturated aliphatic monofunctional carboxylic acid include acrylic acid, methacrylic acid, and linoleic acid.
　芳香族単官能カルボン酸としては、例えば、安息香酸、２－フェノキシ安息香酸、４－メチル安息香酸などが挙げられる。 Examples of the aromatic monofunctional carboxylic acid include benzoic acid, 2-phenoxybenzoic acid, and 4-methylbenzoic acid.
　これらカルボン酸は、単独使用または２種類以上併用することができる。 These carboxylic acids can be used alone or in combination of two or more.
　カルボン酸として、好ましくは、飽和脂肪族単官能カルボン酸、より好ましくは、酢酸が挙げられる。上記のカルボン酸を用いれば、カルボン酸変性リグニンを簡易に得ることができ、また、得られるカルボン酸変性リグニンは、後述するように、有機溶媒に対する溶解性が比較的高く、また、溶融温度が比較的低温（１００～２００℃程度）であるため、取扱性にも優れる。 The carboxylic acid is preferably a saturated aliphatic monofunctional carboxylic acid, and more preferably acetic acid. If the carboxylic acid is used, a carboxylic acid-modified lignin can be easily obtained, and the carboxylic acid-modified lignin obtained has a relatively high solubility in an organic solvent and has a melting temperature as described later. Since it is relatively low temperature (about 100 to 200 ° C.), it is excellent in handleability.
　リグニンは、グアイアシルリグニン（Ｇ型）、シリンギルリグニン（Ｓ型）、ｐ－ヒドロキシフェニルリグニン（Ｈ型）などの基本骨格からなる高分子フェノール性化合物であって、植物全般に含まれている。このような天然リグニンを工業的に取り出したものとしては、例えば、植物原料からパルプをソーダ法、亜硫酸法、クラフト法などによって製造する際、排出される廃液（黒液）中に含まれるソーダリグニン、サルファイトリグニン、クラフトリグニンなどが知られている。 Lignin is a high molecular phenolic compound having a basic skeleton such as guaiacyl lignin (G-type), syringyl lignin (S-type), p-hydroxyphenyl lignin (H-type), and is included in all plants. . Such natural lignin is industrially extracted, for example, soda lignin contained in waste liquid (black liquor) discharged when producing pulp from plant raw materials by soda method, sulfite method, kraft method, etc. , Sulfite lignin, craft lignin and the like are known.
　リグニンとして、具体的には、木本系植物由来リグニン、草本系植物由来リグニンが挙げられる。 Specific examples of lignin include woody plant-derived lignin and herbaceous plant-derived lignin.
　木本系植物由来リグニンとしては、例えば、針葉樹（例えば、スギなど）に含まれる針葉樹系リグニン、例えば、広葉樹に含まれる広葉樹系リグニンなどが挙げられる。このような木本系植物由来リグニンは、Ｈ型を基本骨格とするリグニンを含まず、例えば、針葉樹系リグニンはＧ型を基本骨格とし、広葉樹系リグニンは、Ｇ型およびＳ型を基本骨格としている。 Examples of woody plant-derived lignin include coniferous lignin contained in conifers (eg, cedar), for example, broadleaf lignin contained in broadleaf trees. Such woody plant-derived lignin does not contain lignin having H-type basic skeleton, for example, conifer lignin has G-type basic skeleton, and hardwood lignin has G-type and S-type basic skeleton. Yes.
　草本系植物由来リグニンとしては、例えば、イネ科植物（麦わら、稲わら、とうもろこし、タケなど）に含まれるイネ系リグニンなどが挙げられる。このような草本系植物由来リグニンは、Ｈ型、Ｇ型およびＳ型の全てを基本骨格としている。 Examples of herbaceous plant-derived lignin include rice-based lignin contained in grass family plants (wheat straw, rice straw, corn, bamboo, etc.). Such herbaceous plant-derived lignin has all of H-type, G-type and S-type as the basic skeleton.
　これらのリグニンは、単独使用または２種類以上併用することができる。 These lignins can be used alone or in combination of two or more.
　リグニンとして、好ましくは、草本系植物由来リグニン、より好ましくは、コーンストーバー（とうもろこしの芯、茎、葉など）に由来する草本系植物由来リグニンが挙げられる。 The lignin is preferably a herbaceous plant-derived lignin, more preferably a herbaceous plant-derived lignin derived from corn stover (corn core, stem, leaf, etc.).
　また、リグニンとして、好ましくは、反応性の観点から、Ｈ型の基本骨格を９質量％以上、より好ましくは１４質量％以上の割合で含有することが挙げられる。 Further, as lignin, from the viewpoint of reactivity, it is preferable to contain an H-type basic skeleton in a proportion of 9% by mass or more, more preferably 14% by mass or more.
　カルボン酸変性リグニンの製造方法は、特に制限されず、公知の方法に準拠することができる。 The production method of the carboxylic acid-modified lignin is not particularly limited, and can conform to a known method.
　具体的には、例えば、リグニンの原料となる植物材料（例えば、針葉樹、広葉樹、イネ科植物など）を、カルボン酸（好ましくは、酢酸）を用いて蒸解することによって、パルプ廃液としてカルボン酸変性リグニンを得ることができる。 Specifically, for example, plant materials (for example, conifers, hardwoods, gramineous plants, etc.), which are raw materials for lignin, are digested with carboxylic acid (preferably acetic acid), so that carboxylic acid modification is performed as pulp waste liquid. Lignin can be obtained.
　蒸解方法としては、特に制限されないが、例えば、リグニンの原料となる植物材料と、カルボン酸および無機酸（例えば、塩酸、硫酸など）とを混合し、反応させる。 The cooking method is not particularly limited. For example, a plant material that is a raw material for lignin is mixed with a carboxylic acid and an inorganic acid (for example, hydrochloric acid, sulfuric acid, etc.) and reacted.
　カルボン酸の配合割合は、リグニンの原料となる植物材料１００質量部に対して、カルボン酸（１００％換算）が、例えば、５００質量部以上、好ましくは、９００質量部以上であり、例えば、３００００質量部以下、好ましくは、１５０００質量部以下である。 The mixing ratio of the carboxylic acid is such that the carboxylic acid (100% conversion) is, for example, 500 parts by mass or more, preferably 900 parts by mass or more, for example, 30000 with respect to 100 parts by mass of the plant material that is the raw material for lignin. It is 1 part by mass or less, preferably 15000 parts by mass or less.
　また、無機酸の配合割合は、リグニンの原料となる植物材料１００質量部に対して、無機酸（１００％換算）が、例えば、０．０１質量部以上、好ましくは、０．０５質量部以上であり、例えば、１０質量部以下、好ましくは、５質量部以下である。 The blending ratio of the inorganic acid is, for example, 0.01 parts by mass or more, preferably 0.05 parts by mass or more with respect to 100 parts by mass of the plant material that is the raw material for lignin. For example, it is 10 parts by mass or less, preferably 5 parts by mass or less.
　また、反応条件としては、反応温度が、例えば、３０℃以上、好ましくは、５０℃以上であり、例えば、４００℃以下、好ましくは、２５０℃以下である。また、反応時間が、例えば、０．５時間以上、好ましくは、１時間以上であり、例えば、２０時間以下、好ましくは、１０時間以下である。 As reaction conditions, the reaction temperature is, for example, 30 ° C. or higher, preferably 50 ° C. or higher, for example, 400 ° C. or lower, preferably 250 ° C. or lower. The reaction time is, for example, 0.5 hours or more, preferably 1 hour or more, for example, 20 hours or less, preferably 10 hours or less.
　このような蒸解によって、パルプが得られるとともに、パルプ廃液としてカルボン酸変性リグニンが得られる。 By such cooking, pulp is obtained and carboxylic acid-modified lignin is obtained as a pulp waste liquid.
　次いで、この方法では、濾過などの公知の分離方法によってパルプを分離し、濾液（パルプ廃液）を回収し、必要により、未反応のカルボン酸を、例えば、ロータリーエバポレーター、減圧蒸留などを用いた公知の方法により除去（留去）する。その後、大過剰の水を添加してカルボン酸変性リグニンを沈殿させ、濾過することによって、固形分としてカルボン酸変性リグニンを回収する。 Next, in this method, the pulp is separated by a known separation method such as filtration, and the filtrate (pulp waste liquid) is recovered. If necessary, the unreacted carboxylic acid is known using, for example, a rotary evaporator, vacuum distillation or the like. It is removed (distilled off) by the method. Thereafter, a large excess of water is added to precipitate the carboxylic acid-modified lignin, followed by filtration to recover the carboxylic acid-modified lignin as a solid content.
　また、カルボン酸変性リグニンを得る方法は、上記に限定されず、例えば、カルボン酸により変性されていないリグニン（以下、未変性リグニン）とカルボン酸とを反応させることにより、カルボン酸変性リグニンを得ることもできる。 The method for obtaining carboxylic acid-modified lignin is not limited to the above. For example, carboxylic acid-modified lignin is obtained by reacting lignin not modified with carboxylic acid (hereinafter, unmodified lignin) with carboxylic acid. You can also.
　このような方法では、未変性リグニンとして、好ましくは、粉末状の未変性リグニンが挙げられる。 In such a method, the native lignin is preferably powdered native lignin.
　粉末状の未変性リグニンの平均粒子径は、例えば、０．１μｍ以上、好ましくは、５μｍ以上であり、例えば、１０００μｍ以下、好ましくは、５００μｍ以下である。 The average particle size of the powdered unmodified lignin is, for example, 0.1 μm or more, preferably 5 μm or more, for example, 1000 μm or less, preferably 500 μm or less.
　平均粒子径が上記範囲であれば、未変性リグニンの凝集を抑制して、未変性リグニンをカルボン酸に対して良好に分散することができる。 If the average particle diameter is in the above range, aggregation of the unmodified lignin can be suppressed and the unmodified lignin can be favorably dispersed in the carboxylic acid.
　なお、粉末状の未変性リグニンは、塊状の未変性リグニンを公知の方法で乾燥および粉砕することにより得ることができ、また、市販品を用いることもできる。 The powdered unmodified lignin can be obtained by drying and pulverizing the lump unmodified lignin by a known method, or a commercially available product can be used.
　未変性リグニンとカルボン酸とを反応させる方法としては、例えば、未変性リグニンと、カルボン酸および無機酸（例えば、塩酸、硫酸など）とを混合し、反応させる。 As a method of reacting unmodified lignin and carboxylic acid, for example, unmodified lignin, carboxylic acid and inorganic acid (for example, hydrochloric acid, sulfuric acid, etc.) are mixed and reacted.
　カルボン酸の配合割合は、未変性リグニン１００質量部に対して、カルボン酸（１００％換算）が、例えば、３００質量部以上、好ましくは、５００質量部以上であり、例えば、１５０００質量部以下、好ましくは、１００００質量部以下である。 The mixing ratio of the carboxylic acid is, for example, 300 parts by mass or more, preferably 500 parts by mass or more, for example, 15000 parts by mass or less, based on 100 parts by mass of the unmodified lignin. Preferably, it is 10000 parts by mass or less.
　また、無機酸の配合割合は、未変性リグニン１００質量部に対して、無機酸（１００％換算）が、例えば、０．０１質量部以上、好ましくは、０．０５質量部以上であり、例えば、１０質量部以下、好ましくは、５質量部以下である。 The blending ratio of the inorganic acid is such that the inorganic acid (100% conversion) is, for example, 0.01 parts by mass or more, preferably 0.05 parts by mass or more with respect to 100 parts by mass of the unmodified lignin. 10 parts by mass or less, preferably 5 parts by mass or less.
　また、反応条件としては、反応温度が、例えば、３０℃以上、好ましくは、５０℃以上であり、例えば、４００℃以下、好ましくは、２５０℃以下である。また、反応時間が、例えば、０．５時間以上、好ましくは、１時間以上であり、例えば、２０時間以下、好ましくは、１０時間以下である。 Moreover, as reaction conditions, the reaction temperature is, for example, 30 ° C. or higher, preferably 50 ° C. or higher, for example, 400 ° C. or lower, preferably 250 ° C. or lower. The reaction time is, for example, 0.5 hours or more, preferably 1 hour or more, for example, 20 hours or less, preferably 10 hours or less.
　このようなカルボン酸変性リグニンは、取扱性に優れる。 Such carboxylic acid-modified lignin is excellent in handleability.
　すなわち、カルボン酸により変性されていないリグニンは、有機溶媒に対する溶解性が比較的低く、また、溶融しないため、用途によっては、取扱性に劣る場合がある。 That is, lignin that has not been modified with carboxylic acid has relatively low solubility in organic solvents and does not melt, so that it may be inferior in handleability depending on the application.
　一方、上記のようにカルボン酸により変性されたリグニンは、極性有機溶媒（例えば、アセトン、メタノール、フェノール、テトラヒドロフラン、アセトニトリル、Ｎ－メチルピロリドン、Ｎ，Ｎ－ジメチルホルムアミド、Ｎ，Ｎ－ジメチルアセトアミド、ジメチルスルホキシド、ヘキサメチルホスホニルアミドなど）に対する溶解性が比較的高く、溶融温度が比較的低温（１００～２００℃程度）であるため、取扱性に優れる。 On the other hand, lignin modified with a carboxylic acid as described above is a polar organic solvent (for example, acetone, methanol, phenol, tetrahydrofuran, acetonitrile, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, Dimethyl sulfoxide, hexamethylphosphonilamide, etc.) are relatively high in solubility, and the melting temperature is relatively low (about 100 to 200 ° C.), so that the handling property is excellent.
　また、カルボン酸変性リグニンは、好ましくは、上記した方法により得られる生成物（粗生成物）から、有機溶媒により抽出される。 Also, the carboxylic acid-modified lignin is preferably extracted from the product (crude product) obtained by the above-described method with an organic solvent.
　有機溶媒としては、上記の極性有機溶媒が挙げられ、好ましくは、アセトンが挙げられる。 Examples of the organic solvent include the polar organic solvents described above, and preferably acetone.
　カルボン酸変性リグニンが有機溶媒により抽出されることにより、カルボン酸変性リグニンを精製することができ、エポキシ樹脂硬化物（後述）の耐熱性の向上を図ることができる。 By extracting the carboxylic acid-modified lignin with an organic solvent, the carboxylic acid-modified lignin can be purified, and the heat resistance of the cured epoxy resin (described later) can be improved.
　なお、抽出方法としては、特に制限されず、公知の方法が採用される。 Note that the extraction method is not particularly limited, and a known method is employed.
　カルボン酸変性リグニンの抽出率は、例えば、５０質量％以上、好ましくは、６０質量％以上、より好ましくは、７０質量％以上であり、例えば、９０質量％以下、好ましくは、８０質量％以下である。 The extraction rate of the carboxylic acid-modified lignin is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, for example, 90% by mass or less, preferably 80% by mass or less. is there.
　また、カルボン酸変性リグニンは、好ましくは、フェノール変性される。 The carboxylic acid-modified lignin is preferably phenol-modified.
　カルボン酸変性リグニンをフェノール変性するには、例えば、カルボン酸変性リグニン（フェノール変性されていないカルボン酸変性リグニン）と、フェノール類とを、酸触媒下において反応させる。 In order to phenol-modify carboxylic acid-modified lignin, for example, carboxylic acid-modified lignin (carboxylic acid-modified lignin that has not been phenol-modified) and phenols are reacted in the presence of an acid catalyst.
　フェノール類としては、例えば、フェノール、クレゾール（ｏ－クレゾール、ｍ－クレゾール、ｐ－クレゾールなど）、レゾルシノールなどが挙げられる。 Examples of phenols include phenol, cresol (o-cresol, m-cresol, p-cresol, etc.), resorcinol and the like.
　これらフェノール類は、単独使用または２種類以上併用することができる。 These phenols can be used alone or in combination of two or more.
　フェノール類として、性能向上の観点から、好ましくは、クレゾールが挙げられ、より好ましくは、ｐ－クレゾールが挙げられる。 The phenols are preferably cresol, more preferably p-cresol, from the viewpoint of performance improvement.
　フェノール類の配合割合は、フェノール変性されていないカルボン酸変性リグニン１００質量部に対して、例えば、１００質量部以上、好ましくは、３００質量部以上であり、例えば、５０００質量部以下、好ましくは、３０００質量部以下である。 The blending ratio of the phenols is, for example, 100 parts by mass or more, preferably 300 parts by mass or more, for example, 5000 parts by mass or less, preferably 100 parts by mass or less, based on 100 parts by mass of the carboxylic acid-modified lignin not modified with phenol. It is 3000 parts by mass or less.
　酸触媒としては、特に制限されず、公知の酸触媒が挙げられ、具体的には、例えば、硫酸、硝酸、塩酸などの無機の強酸が挙げられる。 The acid catalyst is not particularly limited, and may be a known acid catalyst. Specific examples include strong inorganic acids such as sulfuric acid, nitric acid, and hydrochloric acid.
　これら酸触媒は、単独使用または２種類以上併用することができる。 These acid catalysts can be used alone or in combination of two or more.
　酸触媒として、低コスト性および性能向上の観点から、好ましくは、硫酸が挙げられる。 The acid catalyst is preferably sulfuric acid from the viewpoint of low cost and improved performance.
　酸触媒の配合割合は、フェノール変性されていないカルボン酸変性リグニン１００質量部に対して、例えば、１質量部以上、好ましくは、５質量部以上であり、例えば、２０質量部以下、好ましくは、１５質量部以下である。 The mixing ratio of the acid catalyst is, for example, 1 part by mass or more, preferably 5 parts by mass or more, for example, 20 parts by mass or less, preferably 100 parts by mass with respect to 100 parts by mass of the carboxylic acid-modified lignin not modified with phenol. 15 parts by mass or less.
　また、カルボン酸変性リグニンとフェノール類との反応において、ホルムアルデヒドを併用することができる。 Also, formaldehyde can be used in combination in the reaction of carboxylic acid-modified lignin and phenols.
　ホルムアルデヒドが用いられる場合には、ホルムアルデヒドと、カルボン酸変性リグニンおよびフェノール類とが共重合され、ホルムアルデヒドが脱水縮合によってメチレン基となり、フェノール変性されたカルボン酸変性リグニン（カルボン酸変性リグニン－フェノール樹脂）において、メチレン基を介してフェノール基を結合する。 When formaldehyde is used, formaldehyde is copolymerized with carboxylic acid-modified lignin and phenols, and formaldehyde becomes a methylene group by dehydration condensation, so that phenol-modified carboxylic acid-modified lignin (carboxylic acid-modified lignin-phenol resin) In this method, a phenol group is bonded through a methylene group.
　ホルムアルデヒドが用いられる場合、その配合割合は、フェノール類１モルに対して、２モル以下、好ましくは、１モル以下である。 When formaldehyde is used, the blending ratio is 2 mol or less, preferably 1 mol or less with respect to 1 mol of phenols.
　また、カルボン酸変性リグニンとフェノール類との反応においては、必要により、溶媒を加えてもよい。溶媒としては、例えば、Ｎ－メチルピロリドン、Ｎ，Ｎ－ジメチルホルムアミド、Ｎ，Ｎ－ジメチルアセトアミド、ジメチルスルホキシド、ヘキサメチルホスホニルアミドなどが挙げられ、好ましくは、Ｎ，Ｎ－ジメチルホルムアミドが挙げられる。 In the reaction of carboxylic acid-modified lignin and phenols, a solvent may be added if necessary. Examples of the solvent include N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphonamide, and preferably N, N-dimethylformamide. .
　溶媒が用いられる場合、その配合量は、カルボン酸変性リグニン１００質量部に対して、例えば、２５質量部以上、好ましくは、４０質量部以上であり、例えば、１００質量部以下、好ましくは、６０質量部以下である。 When a solvent is used, the blending amount is, for example, 25 parts by mass or more, preferably 40 parts by mass or more, for example, 100 parts by mass or less, preferably 60 parts by mass with respect to 100 parts by mass of the carboxylic acid-modified lignin. It is below mass parts.
　そして、カルボン酸変性リグニンと、フェノール類と、さらに、必要によりホルムアルデヒドとを反応させるには、例えば、各成分を上記割合で配合し、加熱すればよい。 In order to react carboxylic acid-modified lignin, phenols, and, if necessary, formaldehyde, for example, each component may be blended in the above ratio and heated.
　反応条件としては、反応温度が、例えば、１００℃以上、好ましくは、１１０℃以上であり、例えば、２００℃以下、好ましくは、１５０℃以下である。また、反応時間が、例えば、３０分以上であり、例えば、３時間以下である。 As reaction conditions, the reaction temperature is, for example, 100 ° C. or more, preferably 110 ° C. or more, for example, 200 ° C. or less, preferably 150 ° C. or less. The reaction time is, for example, 30 minutes or longer, for example, 3 hours or shorter.
　このようにカルボン酸変性リグニンとフェノール類とを反応させることにより、フェノール変性されたカルボン酸変性リグニン（カルボン酸変性リグニンのフェノール変性体、カルボン酸変性リグニン－フェノール樹脂）を得ることができる。 By reacting carboxylic acid-modified lignin and phenols in this way, phenol-modified carboxylic acid-modified lignin (phenol-modified carboxylic acid-modified lignin, carboxylic acid-modified lignin-phenol resin) can be obtained.
　また、反応終了後、必要によりアルカリを添加して酸触媒を中和することができる。 In addition, after the reaction is completed, the acid catalyst can be neutralized by adding an alkali if necessary.
　また、必要により、ろ過、蒸留などの公知の方法により、未反応成分（未反応のフェノール類など）を除去および回収することもできる。なお、蒸留される場合における蒸留条件は特に制限されないが、温度条件が、例えば、１５０℃以上であり、また、圧力条件が、例えば、６０ｍｍＨｇ以下である。なお、回収された未反応成分（未反応のフェノール類など）は、次の生産にそのまま利用することができる。 If necessary, unreacted components (unreacted phenols and the like) can be removed and recovered by a known method such as filtration or distillation. In addition, although distillation conditions in particular in the case of distilling are not restrict | limited, Temperature conditions are 150 degreeC or more, for example, and pressure conditions are 60 mmHg or less, for example. The recovered unreacted components (such as unreacted phenols) can be directly used for the next production.
　また、フェノール変性されたカルボン酸変性リグニンが、溶液として得られる場合（例えば、アルカリ水溶液が添加される場合など）には、その溶液をヘキサンなどの有機溶媒に滴下することによって、フェノール変性されたカルボン酸変性リグニンを沈殿として回収することができる。 In addition, when a phenol-modified carboxylic acid-modified lignin is obtained as a solution (for example, when an alkaline aqueous solution is added), the solution is dropped into an organic solvent such as hexane to add phenol. Carboxylic acid-modified lignin can be recovered as a precipitate.
　さらに、沈殿として回収されたフェノール変性されたカルボン酸変性リグニンを、有機溶媒などに溶解させ、再度、沈殿として回収することにより、フェノール変性されたカルボン酸変性リグニンを精製することもできる。 Furthermore, the phenol-modified carboxylic acid-modified lignin recovered as a precipitate can be dissolved in an organic solvent or the like and recovered as a precipitate again to purify the phenol-modified carboxylic acid-modified lignin.
　また、必要により、フェノール変性されたカルボン酸変性リグニン（カルボン酸変性リグニン－フェノール樹脂）を洗浄することもできる。洗浄方法としては、特に制限されず、例えば、フェノール変性されたカルボン酸変性リグニン（カルボン酸変性リグニン－フェノール樹脂）に水を添加して、攪拌すればよい。このような洗浄によって、不純物や上記中和によって生じる塩などを除去することができる。 If necessary, the phenol-modified carboxylic acid-modified lignin (carboxylic acid-modified lignin-phenol resin) can be washed. The washing method is not particularly limited, and for example, water may be added to phenol-modified carboxylic acid-modified lignin (carboxylic acid-modified lignin-phenol resin) and stirred. By such washing, impurities and salts generated by the neutralization can be removed.
　このようなフェノール変性されたカルボン酸変性リグニン（カルボン酸変性リグニンのフェノール変性体）を用いることにより、エポキシ樹脂硬化物（後述）の耐熱性の向上を図ることができる。 By using such a phenol-modified carboxylic acid-modified lignin (phenol-modified carboxylic acid-modified lignin), the heat resistance of the cured epoxy resin (described later) can be improved.
　そして、カルボン酸変性リグニン（フェノール変性されたカルボン酸変性リグニンを含む（以下同様）。）と、エピクロロヒドリンとの反応においては、例えば、カルボン酸変性リグニンにエピクロロヒドリンを配合し、公知のアルカリ触媒下で反応させる。 In the reaction with carboxylic acid-modified lignin (including phenol-modified carboxylic acid-modified lignin (hereinafter the same)) and epichlorohydrin, for example, epichlorohydrin is blended with carboxylic acid-modified lignin, The reaction is carried out under a known alkali catalyst.
　カルボン酸変性リグニンとエピクロロヒドリンとの配合割合は、カルボン酸変性リグニン１００質量部に対して、エピクロロヒドリンが過剰量であり、具体的には、例えば、１５０質量部以上、好ましくは、２５０質量部以上であり、例えば、２０００質量部以下、好ましくは、１０００質量部以下である。 The mixing ratio of carboxylic acid-modified lignin and epichlorohydrin is an excess amount of epichlorohydrin with respect to 100 parts by mass of carboxylic acid-modified lignin. Specifically, for example, 150 parts by mass or more, preferably 250 parts by mass or more, for example, 2000 parts by mass or less, preferably 1000 parts by mass or less.
　反応条件としては、反応温度が、例えば、８０℃以上、好ましくは、９０℃以上であり、例えば、１２０℃以下、好ましくは、１１０℃以下である。また、反応時間が、例えば、２時間以上、好ましくは、２．５時間以上であり、例えば、４時間以下、好ましくは、３．５時間以下である。 As reaction conditions, the reaction temperature is, for example, 80 ° C. or higher, preferably 90 ° C. or higher, for example, 120 ° C. or lower, preferably 110 ° C. or lower. The reaction time is, for example, 2 hours or more, preferably 2.5 hours or more, for example, 4 hours or less, preferably 3.5 hours or less.
　これにより、カルボン酸変性リグニンに、グリシジルエーテル基を結合させ、エポキシ樹脂を得ることができる。 Thereby, a glycidyl ether group can be bonded to the carboxylic acid-modified lignin to obtain an epoxy resin.
　また、上記の他、例えば、まず、公知の相間移動触媒（例えば、テトラメチルアンモニウム（ＴＢＡＣ）などの四級アンモニウム塩など）の存在下においてカルボン酸変性リグニンにエピクロルヒドリンを上記の割合で付加させ、その後、アルカリ溶液（水酸化ナトリウム水溶液など）を滴下して閉環させる２段階反応により、カルボン酸変性リグニンとエピクロロヒドリンとを結合させ、エポキシ樹脂を得ることもできる。 In addition to the above, for example, first, epichlorohydrin is added to the carboxylic acid-modified lignin in the above ratio in the presence of a known phase transfer catalyst (for example, a quaternary ammonium salt such as tetramethylammonium (TBAC)). Thereafter, an epoxy resin can be obtained by combining carboxylic acid-modified lignin and epichlorohydrin by a two-step reaction in which an alkaline solution (such as an aqueous sodium hydroxide solution) is dropped to close the ring.
　このような場合、１段階目の反応（カルボン酸変性リグニンにエピクロルヒドリンを付加させる反応）における反応温度が、例えば、６０℃以上、好ましくは、７５℃以上であり、例えば、９０℃以下、好ましくは、８５℃以下である。また、反応時間が、例えば、６時間以上、好ましくは、７時間以上であり、例えば、１０時間以下、好ましくは、９時間以下である。 In such a case, the reaction temperature in the first stage reaction (reaction for adding epichlorohydrin to carboxylic acid-modified lignin) is, for example, 60 ° C. or higher, preferably 75 ° C. or higher, for example, 90 ° C. or lower, preferably 85 ° C. or lower. The reaction time is, for example, 6 hours or more, preferably 7 hours or more, for example, 10 hours or less, preferably 9 hours or less.
　また、２段階目の反応（閉環反応）における反応温度が、例えば、２０℃以上、好ましくは、３５℃以上であり、例えば、５０℃以下、好ましくは、４５℃以下である。また、反応時間が、例えば、１０時間以上、好ましくは、１４時間以上であり、例えば、２０時間以下、好ましくは、１６時間以下である。 The reaction temperature in the second stage reaction (ring-closing reaction) is, for example, 20 ° C. or more, preferably 35 ° C. or more, for example, 50 ° C. or less, preferably 45 ° C. or less. The reaction time is, for example, 10 hours or more, preferably 14 hours or more, for example, 20 hours or less, preferably 16 hours or less.
　このようにして得られるエポキシ樹脂において、カルボン酸変性リグニンとエピクロロヒドリンとの結合比率は、通常、カルボン酸変性リグニン１００質量部に対して、エピクロロヒドリンが、２０～３５質量部である。 In the epoxy resin thus obtained, the binding ratio of carboxylic acid-modified lignin and epichlorohydrin is usually 20 to 35 parts by mass of epichlorohydrin with respect to 100 parts by mass of carboxylic acid-modified lignin. is there.
　また、このようにして得られるエポキシ樹脂におけるカルボン酸変性リグニンの含有量は、エポキシ樹脂の総量１００質量部に対して、例えば、７０質量部以上、好ましくは、７５質量部以上であり、例えば、８５質量部以下である。 Further, the content of the carboxylic acid-modified lignin in the epoxy resin thus obtained is, for example, 70 parts by mass or more, preferably 75 parts by mass or more, with respect to 100 parts by mass of the total amount of the epoxy resin. 85 parts by mass or less.
　そして、このようなエポキシ樹脂は、カルボン酸により変性されたリグニンを用いて得られるため、取扱性に優れ、また、エポキシ樹脂硬化物（後述）の耐熱性の向上を図ることができる。さらに、このようなエポキシ樹脂は、カルボン酸により変性されたリグニンを用いて得られるため、カーボンニュートラルに対応しており、環境負荷を低減することができる。
２．エポキシ樹脂硬化剤
　本発明のエポキシ樹脂硬化剤は、カルボン酸変性リグニンを含んでいる。 And since such an epoxy resin is obtained using the lignin modified | denatured with carboxylic acid, it is excellent in handleability and can aim at the improvement of the heat resistance of epoxy resin hardened | cured material (after-mentioned). Furthermore, since such an epoxy resin is obtained using lignin modified with a carboxylic acid, it is compatible with carbon neutral and can reduce the environmental burden.
2. Epoxy resin curing agent The epoxy resin curing agent of the present invention contains a carboxylic acid-modified lignin.
　カルボン酸変性リグニンとしては、上記したカルボン酸変性リグニンが挙げられる。 Examples of the carboxylic acid-modified lignin include the above-described carboxylic acid-modified lignin.
　また、カルボン酸変性リグニンは、好ましくは、有機溶媒により抽出されて用いられる。 Also, the carboxylic acid-modified lignin is preferably extracted with an organic solvent.
　カルボン酸変性リグニンが有機溶媒により抽出されることにより、カルボン酸変性リグニンを精製することができ、エポキシ樹脂硬化物（後述）の耐熱性の向上を図ることができる。 By extracting the carboxylic acid-modified lignin with an organic solvent, the carboxylic acid-modified lignin can be purified, and the heat resistance of the cured epoxy resin (described later) can be improved.
　また、カルボン酸変性リグニンは、好ましくは、フェノール変性されて用いられる。 The carboxylic acid-modified lignin is preferably used after being phenol-modified.
　カルボン酸変性リグニンがフェノール変性されていれば、より一層、エポキシ樹脂硬化物（後述）の耐熱性の向上を図ることができる。 If the carboxylic acid-modified lignin is phenol-modified, the heat resistance of the cured epoxy resin (described later) can be further improved.
　そして、このようなエポキシ樹脂硬化剤は、カルボン酸により変性されたリグニンを用いて得られるため、取扱性に優れ、また、エポキシ樹脂硬化物（後述）の耐熱性の向上を図ることができる。さらに、このようなエポキシ樹脂硬化剤は、カルボン酸により変性されたリグニンを用いて得られるため、カーボンニュートラルに対応しており、環境負荷を低減することができる。
３．エポキシ樹脂組成物
　エポキシ樹脂組成物は、エポキシ樹脂からなる主剤と、エポキシ樹脂硬化剤とを含有している。 And since such an epoxy resin hardening | curing agent is obtained using the lignin modified | denatured by carboxylic acid, it is excellent in handleability and can aim at the improvement of the heat resistance of epoxy resin hardened | cured material (after-mentioned). Furthermore, since such an epoxy resin curing agent is obtained using lignin modified with carboxylic acid, it is compatible with carbon neutral and can reduce environmental burden.
3. Epoxy resin composition The epoxy resin composition contains a main agent composed of an epoxy resin and an epoxy resin curing agent.
　エポキシ樹脂としては、上記した本発明のエポキシ樹脂が挙げられ、また、エポキシ樹脂硬化剤としては、上記した本発明のエポキシ樹脂硬化剤が挙げられる。 Examples of the epoxy resin include the above-described epoxy resin of the present invention, and examples of the epoxy resin curing agent include the above-described epoxy resin curing agent of the present invention.
　また、エポキシ樹脂として、上記した本発明のエポキシ樹脂が用いられる場合には、エポキシ樹脂硬化剤として、例えば、脂肪族アミン類、芳香族アミン類、ポリフェノール化合物、ノボラック樹脂、酸無水物など、公知のエポキシ樹脂硬化剤を用いることができる。 Moreover, when the above-described epoxy resin of the present invention is used as an epoxy resin, known epoxy resin curing agents include, for example, aliphatic amines, aromatic amines, polyphenol compounds, novolak resins, acid anhydrides, and the like. An epoxy resin curing agent can be used.
　また、エポキシ樹脂硬化剤として、上記した本発明のエポキシ樹脂硬化剤が用いられる場合には、エポキシ樹脂として、例えば、ビスフェノール型エポキシ樹脂、ノボラック型エポキシ樹脂など、公知のエポキシ樹脂を用いることができる。 When the above-described epoxy resin curing agent of the present invention is used as the epoxy resin curing agent, a known epoxy resin such as a bisphenol type epoxy resin or a novolac type epoxy resin can be used as the epoxy resin. .
　また、エポキシ樹脂として、上記した本発明のエポキシ樹脂と、公知のエポキシ樹脂とを適宜の割合で併用することができ、また、エポキシ樹脂硬化剤として、上記した本発明のエポキシ樹脂硬化剤と、公知のエポキシ樹脂硬化剤とを適宜の割合で併用することもできる。 Further, as the epoxy resin, the above-described epoxy resin of the present invention and a known epoxy resin can be used in an appropriate ratio, and as the epoxy resin curing agent, the above-described epoxy resin curing agent of the present invention, A well-known epoxy resin hardening | curing agent can also be used together in a suitable ratio.
　好ましくは、エポキシ樹脂として、上記した本発明のエポキシ樹脂を用い、また、エポキシ樹脂硬化剤として、上記した本発明のエポキシ樹脂硬化剤を用いる。 Preferably, the above-described epoxy resin of the present invention is used as the epoxy resin, and the above-described epoxy resin curing agent of the present invention is used as the epoxy resin curing agent.
　主剤（エポキシ樹脂）とエポキシ樹脂硬化剤との配合では、それらを、例えば、エポキシ樹脂硬化剤のアミン当量および／またはフェノール性水酸基当量と、主剤のエポキシ当量とがほぼ等量±２０％当量となるように、配合する。 In the combination of the main agent (epoxy resin) and the epoxy resin curing agent, for example, the amine equivalent and / or phenolic hydroxyl group equivalent of the epoxy resin curing agent and the epoxy equivalent of the main agent are approximately equivalent to ± 20% equivalent. It mix | blends so that it may become.
　また、配合方法としては、特に制限されないが、例えば、主剤（エポキシ樹脂）とエポキシ樹脂硬化剤とを共通の溶媒（例えば、テトラヒドロフラン、アセトン、メチルエチルケトン、メタノール、アセトニトリルなど）に溶解させ、必要に応じて硬化促進剤（後述）を添加し、その後、溶媒を揮発させる。 The blending method is not particularly limited. For example, the main agent (epoxy resin) and the epoxy resin curing agent are dissolved in a common solvent (for example, tetrahydrofuran, acetone, methyl ethyl ketone, methanol, acetonitrile, etc.), and if necessary. Add a curing accelerator (described later), and then volatilize the solvent.
　なお、主剤（エポキシ樹脂）およびエポキシ樹脂硬化剤の溶媒に対する溶解時には、必要に応じて、加熱することができる。加熱温度は、例えば、４０℃以上、好ましくは、５０℃以上であり、例えば、７０℃以下、好ましくは、６０℃以下である。 In addition, when melt | dissolving with respect to the solvent of a main ingredient (epoxy resin) and an epoxy resin hardening | curing agent, it can heat as needed. The heating temperature is, for example, 40 ° C. or higher, preferably 50 ° C. or higher, for example, 70 ° C. or lower, preferably 60 ° C. or lower.
　また、エポキシ樹脂組成物には、適宜のタイミングで、硬化促進剤を添加することができる。 Further, a curing accelerator can be added to the epoxy resin composition at an appropriate timing.
　硬化促進剤としては、例えば、２－エチル－４－メチルイミダゾールおよびその誘導体、１－シアノエチル－２－エチル－４－メチルイミダゾールおよびその誘導体、さらには、ベンジルジメチルアミンなどの３級アミン、トリフェニルフォスフィン（ＴＰＰ）の誘導体（カリボール塩など）、公知の硬化促進剤が挙げられる。 Examples of the curing accelerator include 2-ethyl-4-methylimidazole and derivatives thereof, 1-cyanoethyl-2-ethyl-4-methylimidazole and derivatives thereof, and tertiary amines such as benzyldimethylamine, triphenyl Examples include phosphine (TPP) derivatives (such as caribol salt) and known curing accelerators.
　硬化促進剤が配合される場合、その配合割合は、エポキシ樹脂およびエポキシ樹脂硬化剤の総量１００質量部に対して、例えば、０．１質量部以上、好ましくは、０．２質量部以上であり、例えば、３質量部以下、好ましくは、２質量部以下である。 When the curing accelerator is blended, the blending ratio is, for example, 0.1 parts by mass or more, preferably 0.2 parts by mass or more with respect to 100 parts by mass of the total amount of the epoxy resin and the epoxy resin curing agent. For example, 3 parts by mass or less, preferably 2 parts by mass or less.
　そして、このようなエポキシ樹脂組成物は、エポキシ樹脂および／またはエポキシ樹脂硬化剤において、カルボン酸により変性されたリグニンが用いられるため、取扱性に優れ、また、エポキシ樹脂硬化物の耐熱性の向上を図ることができる。
４．エポキシ樹脂硬化物
　エポキシ樹脂硬化物は、エポキシ樹脂組成物を硬化させることにより得ることができる。 And since such an epoxy resin composition uses lignin modified with a carboxylic acid in an epoxy resin and / or an epoxy resin curing agent, it is excellent in handleability and improves the heat resistance of a cured epoxy resin. Can be achieved.
4). Cured epoxy resin The cured epoxy resin can be obtained by curing the epoxy resin composition.
　エポキシ樹脂組成物を硬化させる方法としては、例えば、エポキシ樹脂組成物を公知の型に注入して加熱する方法や、真空熱プレス成形する方法などが挙げられる。 Examples of the method of curing the epoxy resin composition include a method of injecting the epoxy resin composition into a known mold and heating, a method of vacuum hot press molding, and the like.
　加熱においては、エポキシ樹脂を一段階で加熱してもよく、また、二段階以上の多段階で加熱してもよい。好ましくは、エポキシ樹脂を二段階で加熱する。 In heating, the epoxy resin may be heated in one step, or may be heated in two or more steps. Preferably, the epoxy resin is heated in two stages.
　このような場合、加熱条件としては、一段階目の加熱温度が、例えば、１４０℃以上、好ましくは、１４５℃以上であり、例えば、１６０℃以下、好ましくは、１５５℃以下である。また、一段階目の加熱時間が、例えば、１．５時間以上、好ましくは、２時間以上であり、例えば、３時間以下、好ましくは、２．５時間以下である。 In such a case, as the heating condition, the heating temperature at the first stage is, for example, 140 ° C. or higher, preferably 145 ° C. or higher, for example, 160 ° C. or lower, preferably 155 ° C. or lower. The first stage heating time is, for example, 1.5 hours or more, preferably 2 hours or more, for example, 3 hours or less, preferably 2.5 hours or less.
　また、二段階目の加熱温度が、例えば、１７０℃以上、好ましくは、１７５℃以上であり、例えば、１９０℃以下、好ましくは、１８５℃以下である。また、二段階目の加熱時間が、例えば、２．５時間以上、好ましくは、３時間以上であり、例えば、４時間以下、好ましくは、３．５時間以下である。 In addition, the heating temperature in the second stage is, for example, 170 ° C. or higher, preferably 175 ° C. or higher, for example, 190 ° C. or lower, preferably 185 ° C. or lower. Moreover, the heating time of the second stage is, for example, 2.5 hours or more, preferably 3 hours or more, for example, 4 hours or less, preferably 3.5 hours or less.
　これにより、耐熱性に優れるエポキシ樹脂硬化物を得ることができる。 Thereby, an epoxy resin cured product having excellent heat resistance can be obtained.
　また、このようなエポキシ樹脂硬化物は、機械物性および電気的性質にも優れており、さらに、カルボン酸により変性されたリグニンを用いて得られるため、カーボンニュートラルに対応しており、環境負荷を低減することができる。 In addition, such a cured epoxy resin is excellent in mechanical properties and electrical properties, and is obtained by using lignin modified with carboxylic acid, so it is compatible with carbon neutral and has an environmental impact. Can be reduced.
　そのため、このようなエポキシ樹脂硬化物は、接着剤、成形材料、構造材料、半導体封止材、電子材料などとして、各種産業分野において、広範に用いられる。 Therefore, such a cured epoxy resin is widely used in various industrial fields as an adhesive, a molding material, a structural material, a semiconductor encapsulant, an electronic material, and the like.
　とりわけ、カーボンニュートラル対応や耐熱性が要求される電気製品分野、自動車分野などにおいて、好適に用いられる。 In particular, it is suitably used in the field of electrical products and automobiles that require carbon neutrality and heat resistance.
　次に、本発明を実施例および比較例に基づいて説明するが、本発明は、下記の実施例によって限定されるものではない。また、以下の説明において特に言及がない限り、「部」および「％」は質量基準である。なお、以下に示す実施例の数値は、実施形態において記載される対応する数値（すなわち、上限値または下限値）に代替することができる。 Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. In the following description, “part” and “%” are based on mass unless otherwise specified. In addition, the numerical value of the Example shown below can be substituted to the corresponding numerical value (namely, upper limit value or lower limit value) described in embodiment.
　＜酢酸変性リグニン＞
　　製造例１（抽出なし／フェノール変性なし）
　コーンストーバー１００質量部を、９５質量％の酢酸１０００質量部および硫酸３質量部と混合し、還流下において４時間反応させた。反応後、濾過してパルプを除去し、パルプ廃液を回収した。次いで、ロータリーエバポレーターを用いてパルプ廃液中の酢酸を除去し、体積が１／１０になるまで濃縮した後、その濃縮液の１０倍量（質量基準）の水を添加し、濾過することにより、固形分として酢酸変性リグニンを得た。 <Acetic acid-modified lignin>
Production Example 1 (no extraction / no phenol modification)
100 parts by mass of corn stover was mixed with 1000 parts by mass of 95% by mass acetic acid and 3 parts by mass of sulfuric acid, and reacted for 4 hours under reflux. After the reaction, the pulp was removed by filtration, and the pulp waste liquid was recovered. Next, after removing acetic acid in the pulp waste liquid using a rotary evaporator and concentrating until the volume becomes 1/10, 10 times the amount of the concentrated liquid (mass basis) is added and filtered, Acetic acid-modified lignin was obtained as a solid content.
　　製造例２（抽出なし／フェノール変性あり）
　製造例１と同様の方法により、固形分として酢酸変性リグニンを得た。 Production Example 2 (without extraction / with phenol modification)
In the same manner as in Production Example 1, acetic acid-modified lignin was obtained as a solid content.
　次いで、撹拌機、温度計および冷却管が装着された３００ｍＬの三つ口セパラブルフラスコに、酢酸変性リグニン１００質量部と、ｐ－クレゾール１０００質量部と、９８％硫酸１１質量部とを仕込み、撹拌しながら昇温し、１３０℃において２．５時間反応させた。これにより、酢酸リグニンは、フェノールおよび硫酸と混和し、２０分以内に液化した。 Next, in a 300 mL three-necked separable flask equipped with a stirrer, a thermometer and a condenser tube, 100 parts by mass of acetic acid-modified lignin, 1000 parts by mass of p-cresol, and 11 parts by mass of 98% sulfuric acid were charged. The temperature was raised while stirring and the reaction was carried out at 130 ° C. for 2.5 hours. As a result, lignin acetate was mixed with phenol and sulfuric acid and liquefied within 20 minutes.
　次いで、温度が１００℃以下になるまで冷却し、２０％水酸化ナトリウム水溶液４５．３質量部を添加することにより、中和した。次いで、ろ過により不溶部を除去し、その後、得られた溶液（ろ液）を、その２０倍体積量のヘキサンに滴下することにより、沈殿を得た。 Next, the mixture was cooled to a temperature of 100 ° C. or lower and neutralized by adding 45.3 parts by mass of a 20% aqueous sodium hydroxide solution. Subsequently, the insoluble part was removed by filtration, and then the obtained solution (filtrate) was dropped into 20 times volume of hexane to obtain a precipitate.
　次いで、得られた沈殿を、吸引ろ過により回収し、必要最小限（約１００質量部）のテトラヒドロフラン（ＴＨＦ）に溶解させた。次いで、得られた溶液を、テトラヒドロフランの２０倍体積量のヘキサンに滴下することにより、再度沈殿を得た。 Next, the obtained precipitate was collected by suction filtration and dissolved in the necessary minimum (about 100 parts by mass) of tetrahydrofuran (THF). Next, the obtained solution was added dropwise to 20 times volume of hexane in tetrahydrofuran to obtain a precipitate again.
　次いで、上記したろ過、テトラヒドロフランに対する溶解およびヘキサンの滴下の操作を、一度繰り返し、得られた沈殿を吸引ろ過により回収した。 Subsequently, the above-described filtration, dissolution in tetrahydrofuran and dropwise addition of hexane were repeated once, and the resulting precipitate was collected by suction filtration.
　その後、得られた沈殿を、６０℃、４０ｍｍＨｇの条件下で１５時間乾燥させることにより、酢酸リグニンのフェノール変性体を得た。 Thereafter, the obtained precipitate was dried under the conditions of 60 ° C. and 40 mmHg for 15 hours to obtain a phenol-modified product of lignin acetate.
　　製造例３（抽出あり／フェノール変性なし）
　製造例１と同様の方法により、固形分として酢酸変性リグニンを得た。 Production Example 3 (with extraction / no phenol modification)
In the same manner as in Production Example 1, acetic acid-modified lignin was obtained as a solid content.
　次いで、得られた酢酸変性リグニンを、有機溶媒（アセトン）に溶解させ、不溶物を濾過により除去した。その後、酢酸変性リグニンの有機溶媒溶液を乾燥させることにより、酢酸変性リグニン（有機溶媒による抽出物）を得た。 Next, the obtained acetic acid-modified lignin was dissolved in an organic solvent (acetone), and insoluble matters were removed by filtration. Thereafter, an organic solvent solution of acetic acid-modified lignin was dried to obtain acetic acid-modified lignin (an extract with an organic solvent).
　　製造例４（抽出あり／フェノール変性あり）
　製造例３で得られた酢酸変性リグニン（有機溶媒による抽出物）を用いた以外は、製造例２と同様にして、酢酸変性リグニンをフェノール変性させた。これにより、酢酸リグニン（有機溶媒による抽出物）のフェノール変性体を得た。 Production Example 4 (with extraction / with phenol modification)
The acetic acid-modified lignin was phenol-modified in the same manner as in Production Example 2 except that the acetic acid-modified lignin obtained in Production Example 3 (extract with an organic solvent) was used. As a result, a phenol-modified product of lignin acetate (extract with an organic solvent) was obtained.
　　比較製造例１（抽出なし／フェノール変性なし）
　麦わらのアルカリ蒸解パルプ廃液（黒液）を中和した後、濾過することにより、固形分として未変性リグニンを得た。 Comparative production example 1 (no extraction / no phenol modification)
After neutralizing the straw straw alkaline digested pulp waste liquor (black liquor), it was filtered to obtain unmodified lignin as a solid content.
　　比較製造例２（抽出なし／フェノール変性あり）
　麦わらのアルカリ蒸解パルプ廃液（黒液）を中和した後、濾過することにより、固形分として未変性リグニンを得た。 Comparative Production Example 2 (without extraction / with phenol modification)
After neutralizing the straw straw alkaline digested pulp waste liquor (black liquor), it was filtered to obtain unmodified lignin as a solid content.
　この未変性リグニンを用いて、製造例２と同様にして、未変性リグニンをフェノール変性させた。これにより、未変性リグニン（カルボン酸により変性されていないリグニン）のフェノール変性体を得た。 Using this unmodified lignin, the unmodified lignin was phenol-modified in the same manner as in Production Example 2. As a result, a phenol-modified product of unmodified lignin (lignin not modified with carboxylic acid) was obtained.
　　比較製造例３（抽出あり／フェノール変性なし）
　比較製造例１と同様の方法により、固形分として未変性リグニンを得た。 Comparative Production Example 3 (with extraction / no phenol modification)
In the same manner as in Comparative Production Example 1, unmodified lignin was obtained as a solid content.
　次いで、得られた未変性リグニンを、有機溶媒（メタノール）に溶解させ、不溶物を濾過により除去した。その後、未変性リグニンの有機溶媒溶液を乾燥させることにより、未変性リグニン（有機溶媒による抽出物）を得た。 Next, the obtained unmodified lignin was dissolved in an organic solvent (methanol), and insoluble matters were removed by filtration. Thereafter, an organic solvent solution of native lignin was dried to obtain native lignin (an extract with an organic solvent).
　　比較製造例４（抽出あり／フェノール変性あり）
　比較製造例３で得られた未変性リグニン（有機溶媒による抽出物）を用いた以外は、製造例２と同様にして、未変性リグニンをフェノール変性させた。これにより、未変性リグニン（有機溶媒による抽出物）のフェノール変性体を得た。 Comparative Production Example 4 (with extraction / with phenol modification)
The unmodified lignin was phenol-modified in the same manner as in Production Example 2, except that the unmodified lignin obtained in Comparative Production Example 3 (extract with an organic solvent) was used. As a result, a phenol-modified product of unmodified lignin (extract with an organic solvent) was obtained.
　＜エポキシ樹脂＞
　　実施例１
　撹拌モーター、温度計、滴下ロートおよび還流冷却管が装着された１Ｌの四つ口フラスコに、製造例３で得られた酢酸変性リグニン（有機溶媒による抽出物）２２４質量部と、過剰量のエピクロロヒドリン１８５０質量部と、相間移動触媒としての塩化テトラメチルアンモニウム２７．４質量部とを仕込み、水０．９質量部を加えて、窒素気流下において８０℃で８時間反応させた。 <Epoxy resin>
Example 1
In a 1 L four-necked flask equipped with a stirring motor, a thermometer, a dropping funnel and a reflux condenser, 224 parts by mass of acetic acid-modified lignin (extracted with an organic solvent) obtained in Production Example 3 and an excess amount of epi 1850 parts by mass of chlorohydrin and 27.4 parts by mass of tetramethylammonium chloride as a phase transfer catalyst were added, 0.9 part by mass of water was added, and the mixture was reacted at 80 ° C. for 8 hours in a nitrogen stream.
　次いで、４０℃において２０質量％水酸化ナトリウム水溶液５０ｇを滴下し、１５時間撹拌した。その後、室温まで冷却し、２０質量％酢酸水溶液を滴下して中和させた。 Next, 50 g of a 20% by mass aqueous sodium hydroxide solution was added dropwise at 40 ° C. and stirred for 15 hours. Then, it cooled to room temperature and 20 mass% acetic acid aqueous solution was dripped and neutralized.
　次いで、得られた溶液を、分液漏斗に移し、１００ｍＬのイオン交換水により５回洗浄した後、無水硫酸マグネシウムを加えて水分を除去した。 Next, the obtained solution was transferred to a separatory funnel and washed five times with 100 mL of ion exchange water, and then anhydrous magnesium sulfate was added to remove moisture.
　次いで、硫酸マグネシウムをろ過によって除去し、得られた溶液（ろ液）を、その溶液の２０倍体積量のヘキサン／ジエチルエーテル混合溶媒（混合比７／３（体積比））に滴下し、沈殿を生成させた。 Next, magnesium sulfate is removed by filtration, and the resulting solution (filtrate) is added dropwise to a 20-fold volume of hexane / diethyl ether mixed solvent (mixing ratio 7/3 (volume ratio)) of the solution to precipitate. Was generated.
　その後、得られた沈殿を吸引ろ過により回収し、６０℃、４０ｍｍＨｇの条件下で１５時間乾燥させることにより、エポキシ樹脂を得た。 Thereafter, the resulting precipitate was collected by suction filtration and dried under conditions of 60 ° C. and 40 mmHg for 15 hours to obtain an epoxy resin.
　得られたエポキシ樹脂のエポキシ当量（ＥＥＷ）は、２８０であった。 The epoxy equivalent (EEW) of the obtained epoxy resin was 280.
　なお、エポキシ当量（ＥＥＷ）は、次の方法により測定した。 The epoxy equivalent (EEW) was measured by the following method.
　すなわち、得られたエポキシ樹脂（エポキシ化リグニン）を、重水素化クロロホルムに溶解させ、基準物質である１，１’，２，２’－テトラクロロエタン（ＴＣＥ）を添加した後、１Ｈ－ＮＭＲスペクトルを測定して、各ピークの積分強度比から下記式によりエポキシ当量を算出した（以下同様）。 That is, the obtained epoxy resin (epoxidized lignin) was dissolved in deuterated chloroform, 1,1 ′, 2,2′-tetrachloroethane (TCE) as a reference material was added, and then 1 H-NMR The spectrum was measured, and the epoxy equivalent was calculated from the integrated intensity ratio of each peak according to the following formula (hereinafter the same).
数式Formula
Figure JPOXMLDOC01-appb-I000001
Figure JPOXMLDOC01-appb-I000001
　　ＩＴＣＥ：１，１’，２，２’－テトラクロロエタン（ＴＣＥ）の積分強度
　　Ｉｅｐｏｘｙ：エポキシ基の積分強度
　　Ｗｅｐｏｘｙ　ｒｅｓｉｎ：エポキシ樹脂（エポキシ化リグニン）の質量
　　ＷＴＣＥ：１，１’，２，２’－テトラクロロエタン（ＴＣＥ）の質量
　　ＭＴＣＥ：１，１’，２，２’－テトラクロロエタン（ＴＣＥ）の分子量
　　比較例１
　比較製造例３で得られた未変性リグニン（有機溶媒による抽出物）を用いた以外は、実施例１と同様にして、エポキシ樹脂を得た。得られたエポキシ樹脂のエポキシ当量は、２９０であった。 I TCE : Integral intensity of 1,1 ′, 2,2′-tetrachloroethane (TCE) I epoxy : Integral intensity of epoxy group W epoxy resin : Mass of epoxy resin (epoxidized lignin) W TCE : 1,1 ′, Mass of 2,2′-tetrachloroethane (TCE) M TCE : Molecular weight of 1,1 ′, 2,2′-tetrachloroethane (TCE) Comparative Example 1
An epoxy resin was obtained in the same manner as in Example 1 except that the unmodified lignin (extract with an organic solvent) obtained in Comparative Production Example 3 was used. The epoxy equivalent of the obtained epoxy resin was 290.
　　評価１
　各エポキシ樹脂の性能を調べるために、エポキシ樹脂とエポキシ樹脂硬化剤とを配合し、硬化させた。なお、エポキシ樹脂硬化剤としては、市販のノボラック樹脂（フェノライトＴＤ－２１３１、ＤＩＣ社製）を使用した。 Evaluation 1
In order to examine the performance of each epoxy resin, an epoxy resin and an epoxy resin curing agent were blended and cured. As the epoxy resin curing agent, a commercially available novolak resin (Phenolite TD-2131, manufactured by DIC Corporation) was used.
　より具体的には、まず、エポキシ樹脂のエポキシ当量と、エポキシ樹脂硬化剤のアミン当量および／またはフェノール性水酸基当量とがほぼ等量となるように、エポキシ樹脂とエポキシ樹脂硬化剤とを用意し、それらをテトラヒドロフランに溶解させ、次いで、硬化促進剤（１－シアノエチル－２－エチル－４－メチルイミダゾール）を、エポキシ樹脂とエポキシ樹脂硬化剤との総量１００質量部に対して０．５質量部となるように添加することにより、ワニスを得た。次いで、得られたワニスをフィルム上にキャストして、６０℃で２時間乾燥させ、テトラヒドロフランを除去することにより、エポキシ樹脂組成物を得た。 More specifically, first, an epoxy resin and an epoxy resin curing agent are prepared so that the epoxy equivalent of the epoxy resin and the amine equivalent and / or phenolic hydroxyl group equivalent of the epoxy resin curing agent are approximately equal. Then, they are dissolved in tetrahydrofuran, and then a curing accelerator (1-cyanoethyl-2-ethyl-4-methylimidazole) is added in an amount of 0.5 parts by mass with respect to 100 parts by mass of the total amount of the epoxy resin and the epoxy resin curing agent. The varnish was obtained by adding so that it might become. Subsequently, the obtained varnish was cast on a film, dried at 60 ° C. for 2 hours, and tetrahydrofuran was removed to obtain an epoxy resin composition.
　その後、テフロン（登録商標）の型に充填し、真空プレス中１５０℃で２時間加熱し、続いて、１８０℃で３時間加熱することにより、硬化させた。なお、エポキシ樹脂組成物は、加熱時に溶融して流動性を示した後、硬化した。 Thereafter, the product was filled in a Teflon (registered trademark) mold, heated in a vacuum press at 150 ° C. for 2 hours, and then heated at 180 ° C. for 3 hours to be cured. The epoxy resin composition was cured after being melted and exhibited fluidity, and then cured.
　得られたエポキシ樹脂硬化物について、以下の方法で評価した。その結果を、表１に示す。 The obtained cured epoxy resin was evaluated by the following method. The results are shown in Table 1.
　（１）ガラス転移温度
　動的粘弾性分析（ＤＶＡ）により測定した。測定装置として、ＳＩＩナノテクノロジー社製　ＤＭＳ－６１００を用いた。試験片の大きさは１０ｍｍ×４０ｍｍ×２ｍｍとした。測定モードは三点曲げモードであり、測定条件は、空気条件下、温度範囲－１００℃～３００℃、昇温速度５℃／ｍｉｎ、周波数１Ｈｚとした。これにより得られるｔａｎδ曲線のα緩和ピーク温度を、ガラス転移温度（Ｔｇ）とした。 (1) Glass transition temperature It was measured by dynamic viscoelasticity analysis (DVA). As a measuring device, DMS-6100 manufactured by SII Nano Technology was used. The size of the test piece was 10 mm × 40 mm × 2 mm. The measurement mode was a three-point bending mode. The measurement conditions were an air condition, a temperature range of −100 ° C. to 300 ° C., a temperature increase rate of 5 ° C./min, and a frequency of 1 Hz. The α relaxation peak temperature of the tan δ curve thus obtained was defined as the glass transition temperature (Tg).
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　＜エポキシ樹脂硬化剤＞
　　実施例２
　製造例２において得られた酢酸リグニンのフェノール変性体を、エポキシ樹脂硬化剤とした。 <Epoxy resin curing agent>
Example 2
The phenol-modified product of lignin acetate obtained in Production Example 2 was used as an epoxy resin curing agent.
　　実施例３
　製造例４において得られた酢酸変性リグニン（有機溶媒による抽出物）のフェノール変性体を、エポキシ樹脂硬化剤とした。 Example 3
The phenol-modified product of acetic acid-modified lignin (extracted with an organic solvent) obtained in Production Example 4 was used as an epoxy resin curing agent.
　　比較例２
　比較製造例２において得られた未変性リグニンのフェノール変性体を、エポキシ樹脂硬化剤とした。 Comparative Example 2
The phenol-modified product of unmodified lignin obtained in Comparative Production Example 2 was used as an epoxy resin curing agent.
　　比較例３
　比較製造例４において得られた未変性リグニン（有機溶媒による抽出物）のフェノール変性体を、エポキシ樹脂硬化剤とした。 Comparative Example 3
The phenol-modified product of unmodified lignin (extracted with an organic solvent) obtained in Comparative Production Example 4 was used as an epoxy resin curing agent.
　　評価２
　各エポキシ樹脂硬化剤の性能を調べるために、エポキシ樹脂とエポキシ樹脂硬化剤とを配合し、硬化させた。なお、エポキシ樹脂としては、市販のビスフェノールＡ型エポキシ樹脂（商品名ＪＥＲ　８２８、三菱化学社製）を使用した。 Evaluation 2
In order to examine the performance of each epoxy resin curing agent, an epoxy resin and an epoxy resin curing agent were blended and cured. As the epoxy resin, a commercially available bisphenol A type epoxy resin (trade name JER 828, manufactured by Mitsubishi Chemical Corporation) was used.
　より具体的には、まず、エポキシ樹脂のエポキシ当量と、エポキシ樹脂硬化剤のアミン当量および／またはフェノール性水酸基当量とがほぼ等量となるように、エポキシ樹脂とエポキシ樹脂硬化剤とを用意し、それらをテトラヒドロフランに溶解させ、次いで、硬化促進剤（１－シアノエチル－２－エチル－４－メチルイミダゾール）を、エポキシ樹脂とエポキシ樹脂硬化剤との総量１００質量部に対して０．５質量部となるように添加することにより、ワニスを得た。次いで、得られたワニスをフィルム上にキャストして、６０℃で２時間乾燥させ、テトラヒドロフランを除去することにより、エポキシ樹脂組成物を得た。 More specifically, first, an epoxy resin and an epoxy resin curing agent are prepared so that the epoxy equivalent of the epoxy resin and the amine equivalent and / or phenolic hydroxyl group equivalent of the epoxy resin curing agent are approximately equal. Then, they are dissolved in tetrahydrofuran, and then a curing accelerator (1-cyanoethyl-2-ethyl-4-methylimidazole) is added in an amount of 0.5 parts by mass with respect to 100 parts by mass of the total amount of the epoxy resin and the epoxy resin curing agent. The varnish was obtained by adding so that it might become. Subsequently, the obtained varnish was cast on a film, dried at 60 ° C. for 2 hours, and tetrahydrofuran was removed to obtain an epoxy resin composition.
　その後、テフロン（登録商標）の型に充填し、真空プレス中１５０℃で２時間加熱し、続いて、１８０℃で３時間加熱することにより、硬化させた。なお、エポキシ樹脂組成物は、加熱時に溶融して流動性を示した後、硬化した。 Thereafter, the product was filled in a Teflon (registered trademark) mold, heated in a vacuum press at 150 ° C. for 2 hours, and then heated at 180 ° C. for 3 hours to be cured. The epoxy resin composition was cured after being melted and exhibited fluidity, and then cured.
　得られたエポキシ樹脂硬化物について、上記と同様の方法で評価した。その結果を、表２に示す。 The obtained epoxy resin cured product was evaluated by the same method as described above. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
＜考察＞
　上記の評価１および評価２が参照されるように、酢酸により変性されたリグニンを用いて得られるエポキシ樹脂およびエポキシ樹脂硬化剤によれば、流動性が比較的高いエポキシ樹脂組成物を得ることができるため、エポキシ樹脂組成物およびその硬化物の取扱性に優れることが確認された。 <Discussion>
As described in Evaluation 1 and Evaluation 2 above, according to the epoxy resin and the epoxy resin curing agent obtained by using lignin modified with acetic acid, an epoxy resin composition having relatively high fluidity can be obtained. Therefore, it was confirmed that the epoxy resin composition and its cured product are excellent in handleability.
　また、上記の評価１および評価２が参照されるように、酢酸により変性されたリグニンを用いて得られるエポキシ樹脂およびエポキシ樹脂硬化剤によれば、ガラス転移温度が比較的高く、耐熱性に優れるエポキシ樹脂硬化物が得られることが確認された。 Further, as referred to in the above evaluations 1 and 2, the epoxy resin and the epoxy resin curing agent obtained using lignin modified with acetic acid have a relatively high glass transition temperature and excellent heat resistance. It was confirmed that a cured epoxy resin was obtained.
　　評価３
　エポキシ樹脂硬化物の耐熱性について、以下の方法でさらに評価した。サンプルとして、実施例１および比較例１のエポキシ樹脂を用いて得られたエポキシ樹脂硬化物を用いた。その結果を、表３に示す。 Evaluation 3
The heat resistance of the cured epoxy resin was further evaluated by the following method. As a sample, the cured epoxy resin obtained using the epoxy resin of Example 1 and Comparative Example 1 was used. The results are shown in Table 3.
　（２）５％重量減少温度、１０％重量減少温度（耐熱分解性）
　熱重量分析（ＴＧＡ）により測定した。測定装置として、島津製作所製　ＴＧＡ－５０を用いた。より具体的には、金やすりで粉末状にした試料を、重量が３～４ｍｇになるように白金セルに量り取り、温度範囲：室温～８００℃、昇温速度１０℃／ｍｉｎ、窒素気流（２０ｍＬ／ｍｉｎ）下の条件で測定した。４０℃での重量を基準として、重量が５％減少した際の温度を５％重量減少温度（Ｔｄ５）、１０％減少した際の温度を１０％重量減少温度（Ｔｄ１０）とした。 (2) 5% weight reduction temperature, 10% weight reduction temperature (heat decomposability)
It was measured by thermogravimetric analysis (TGA). As a measuring device, TGA-50 manufactured by Shimadzu Corporation was used. More specifically, a sample made into a powder form with a gold file is weighed into a platinum cell so that the weight is 3 to 4 mg, and the temperature range is from room temperature to 800 ° C., the heating rate is 10 ° C./min, and the nitrogen stream ( 20 mL / min). Based on the weight at 40 ° C., the temperature when the weight decreased by 5% was defined as the 5% weight decrease temperature (T d5 ), and the temperature when decreased by 10% was defined as the 10% weight decrease temperature (T d10 ).
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
＜考察＞
　上記の評価３が参照されるように、酢酸により変性されたリグニンを用いて得られるエポキシ樹脂によれば、５％重量減少温度および１０％重量減少温度が比較的高く、耐熱性に優れるエポキシ樹脂硬化物が得られることが確認された。 <Discussion>
As referred to in the evaluation 3, the epoxy resin obtained by using lignin modified with acetic acid has a relatively high 5% weight reduction temperature and 10% weight reduction temperature, and is excellent in heat resistance. It was confirmed that a cured product was obtained.
　なお、上記発明は、本発明の例示の実施形態として提供したが、これは単なる例示に過ぎず、限定的に解釈してはならない。当該技術分野の当業者によって明らかな本発明の変形例は、後記請求の範囲に含まれる。 Although the above invention has been provided as an exemplary embodiment of the present invention, this is merely an example and should not be interpreted in a limited manner. Variations of the present invention that are apparent to one of ordinary skill in the art are within the scope of the following claims.
 　本発明のエポキシ樹脂およびエポキシ樹脂硬化剤を用いて得られるエポキシ樹脂硬化物は、半導体封止材などの電気電子部品や、例えば、塗料、接着剤などの各種工業分野において、広範に用いられる。
  The epoxy resin cured product obtained by using the epoxy resin and the epoxy resin curing agent of the present invention is widely used in various electronic fields such as electrical and electronic parts such as semiconductor sealing materials, and paints and adhesives.

Claims (6)

  1. 　カルボン酸により変性されたリグニンと、エピクロロヒドリンとを少なくとも反応させることにより得られることを特徴とする、エポキシ樹脂。 An epoxy resin obtained by reacting at least lignin modified with carboxylic acid and epichlorohydrin.
  2. 　前記カルボン酸により変性された前記リグニンが、フェノール変性されている、請求項１に記載のエポキシ樹脂。 The epoxy resin according to claim 1, wherein the lignin modified with the carboxylic acid is phenol-modified.
  3. 　前記カルボン酸により変性された前記リグニンが、有機溶媒により抽出されている、請求項１に記載のエポキシ樹脂。 The epoxy resin according to claim 1, wherein the lignin modified with the carboxylic acid is extracted with an organic solvent.
  4. 　カルボン酸により変性されたリグニンを含むことを特徴とする、エポキシ樹脂硬化剤。 An epoxy resin curing agent comprising lignin modified with carboxylic acid.
  5. 　前記カルボン酸により変性された前記リグニンが、フェノール変性されている、請求項４に記載のエポキシ樹脂硬化剤。 The epoxy resin curing agent according to claim 4, wherein the lignin modified with the carboxylic acid is phenol-modified.
  6. 　前記カルボン酸により変性された前記リグニンが、有機溶媒により抽出されている、請求項４に記載のエポキシ樹脂硬化剤。 The epoxy resin curing agent according to claim 4, wherein the lignin modified with the carboxylic acid is extracted with an organic solvent.
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