JP6955498B2 - Manufacturing method of heat-resistant lignin - Google Patents

Description

The present invention relates to heat resistant lignin.

Due to the growing environmental awareness in recent years, biomass-derived raw materials are attracting attention. For example, although it is particularly remarkable in the production of bioethanol, raw materials that compete with food such as starch and sugar are often used as raw materials derived from biomass. Therefore, problems such as rising food prices and decreasing food production have been pointed out. Therefore, at present, a technique for producing a raw material from cellulosic biomass that does not compete with food is drawing attention.

Cellulose-based biomass that does not compete with food includes, for example, palm palm tree trunks and bunches, palm palm fruit fibers and seeds, bagasse (squeezed sorghum (including high biomass amount sugar)), rice straw, straw, and corn cobs. Examples include foliage / corn residue (corn stover, corn cob, corn hull), sorghum (including sweet sorghum) residue, yatropha seed coat and shell, cashew shell, wood chips, switchgrass, and elastomer.
These cellulosic biomasses contain 20 to 30% by mass of lignin in addition to cellulose and hemicellulose. For example, in the papermaking process, lignin has been separated from cellulose and hemicellulose, recovered as black liquor, and mainly used as fuel. However, it is desired to extract lignin because a phenol derivative can be produced by decomposing lignin and conversion into chemicals and bioplastics can be expected.

However, when lignin is used as an industrial material such as a resin material such as a chemical product, there is a problem that it is inferior in physical properties such as heat resistance.
Patent Document 1 discloses a lignin derivative obtained by decomposing biomass by stirring the biomass under high temperature and high pressure in the presence of a solvent. After the above decomposition treatment, the water-insoluble component is extracted with acetone, and the acetone is distilled off to obtain a lignin derivative.
Patent Document 2 discloses a lignin-based polymer containing a 1,1-diphenylpropane unit in which a phenol derivative is grafted at the α-position of the phenylpropane unit of lignin and having an ester moiety in which one or more hydroxyl groups are acylated. do. Since the lignophenol derivative is recovered as an aggregate containing various chemical structures derived from natural lignin, heat treatment by thermal annealing is performed to homogenize the molecular weight fraction and structural diversity.

Patent No. 5256679 Japanese Unexamined Patent Publication No. 2011-256381

However, the lignin extracted in Patent Document 1 has many components having too small a molecular weight, has poor heat resistance for using lignin as a resin, and is secondarily induced in a separate reaction kettle in order to improve workability. It has a problem that it is not suitable for using lignin as it is.
In Patent Document 2, since another phenolic hydroxyl group is bonded to an unreacted benzylic hydroxyl group derived from natural lignin or the hydroxyl group is acylated and modified, thermal annealing treatment is performed at a temperature of 200 ° C. or higher. At the same time, the reaction site derived from natural lignin disappears, which makes it less attractive as a material. Further, even in this method, it is necessary to separately perform secondary induction in a reaction kettle.

The present invention is to provide lignin having high heat resistance without imparting (secondary derivatization) a functional group having a hydroxyl group or the like for the purpose of improving reactivity while maintaining a structure derived from natural lignin. ..

As a result of diligent studies, the present inventors have found that the above problems can be solved by a manufacturing method having the following steps, and have completed the present invention.
That is, the present invention provides the following [1] to [10].
[1] The raw material lignin solution is mixed with at least one solvent (a) selected from water having a volume of 1 to 50 times that of the raw material lignin solution and a hydrocarbon having a dipole moment of 0.25 d or less. A method for producing a heat-resistant lignin, which comprises the step (I).
[2] The raw material lignin solution is a lignin solution obtained by solubilizing lignin from a plant-based biomass in a solvent containing an organic solvent, or a solution obtained by dissolving solid lignin in a solvent containing an organic solvent. The method for producing a heat-resistant lignin according to [1].
[3] The method for producing a heat-resistant lignin according to the above [2], wherein the organic solvent is at least one selected from alcohols, ethers and ketone compounds.
[4] The heat resistance according to any one of the above [1] to [3], which further requires the following step (II-1) when the solution obtained in the step (I) is two-phase. Lignin manufacturing method:
(II-1) The organic phase containing heat-resistant lignin is separated from the solution obtained in step (I), and the organic phase is concentrated.
[5] The heat resistance according to any one of the above [1] to [3], which further requires the following step (II-2) when the solution obtained in the step (I) is one phase. Lignin manufacturing method:
(II-2) The solution is solid-liquid separated.
[6] (1) The glass transition temperature T _g by the dynamic viscoelasticity measurement method (DMA method) is 70 ° C. or higher, (2) the number average molecular weight is 600 or higher, and (3) differential thermal and thermogravimetric analysis. A heat-resistant lignin obtained by the production method according to any one of the above [1] to [5], wherein the 5% thermogravimetric reduction start temperature in the simultaneous measurement (TG-DTA measurement) is 210 ° C. or higher.
[7] The heat-resistant lignin according to [6] above, which further satisfies the following requirements (4) and (5): (4) Integrated molecular weight obtained by gel permeation chromatography (GPC) using polystyrene as a conversion standard. In the distribution curve, the proportion of constituents having a molecular weight of 320 or less is 15% or less, and (5) in the integrated molecular weight distribution curve obtained by gel permeation chromatography (GPC) using polystyrene as a conversion standard, the molecular weight is 3200 or more. The proportion of the constituent components is 7% or more and 50% or less.
[8] A resin composition containing the heat-resistant lignin according to the above [6] or [7], and a molded product using the resin composition.
[9] A step (IA) of adding a resin to a raw material lignin solution to obtain a lignin-resin-containing solution, and a volume of 1 to 50 times that of the lignin-resin-containing solution and the lignin-resin-containing solution. A method for producing a lignin-containing resin composition, which comprises the following step (IB) of mixing water and at least one solvent (a') of a solvent selected from hydrocarbons having a dipole moment of 0.25 d or less. ..
[10] A lignin-containing resin composition obtained by the method according to the above [9] and a molded product using the resin composition.

According to the present invention, it is possible to provide lignin having high heat resistance without secondary derivatization while maintaining the structure derived from natural lignin.

Hereinafter, embodiments of the present invention will be described in detail.

<Manufacturing method of heat-resistant lignin>
The method for producing the heat-resistant lignin in the present embodiment is at least one selected from a raw material lignin solution, water having a volume of 1 to 50 times that of the raw material lignin solution, and a hydrocarbon having a dipole moment of 0.25 d or less. It comprises a step (I) of mixing with the seed solvent (a).

[Plant-based biomass]
Examples of plant-based biomass include wood-based biomass and herbaceous biomass. Examples of woody biomass include conifers and broad-leaved trees such as Sugi, Hinoki, Hiba, Sakura, Eucalyptus, Beech, and Bamboo.
Herbaceous biomass includes palm tree trunks and bunches, palm palm fruit fibers and seeds, bagasse (sorghum and high biomass sorghum), cane tops (sorghum tops and leaves), energy canes, rice straw, straw, Corn cob, foliage, residue (corn stover, corn cob, corn hull), sorghum (including sweet sorghum) residue, jatropha skin and shell, cashew shell, switchgrass, erianthus, high biomass yield crop, energy crop, etc. Can be mentioned.
Among these, herbaceous biomass is preferable from the viewpoint of availability and compatibility with the production method applied in the present invention, and palm palm air chamber, straw, corn foliage, bagasse, cane top, energy cane. , The residue after extraction of these useful components is more preferable, and bagasse, cane top, and energy cane are further preferable. Useful ingredients include, for example, hemicellulose, sugars, minerals, water and the like.
Bagasse contains about 5 to 30% by mass of lignin. In addition, lignin in bagasse contains all of H nucleus, G nucleus and S nucleus as a basic skeleton. The G nucleus has one methoxy group (-OCH ₃ ) at the ortho position of the phenol skeleton portion, the S nucleus has two methoxy groups at the ortho position, and the H nucleus is It does not have a methoxy group at the ortho position. The lignin derived from Kimoto-based biomass does not contain H nuclei.
As the plant-based biomass, crushed biomass can also be used. Further, it may be in any form of a block, a chip, a powder, or a water-containing substance containing water.

As the raw material lignin solution, a lignin solution (i) obtained by solubilizing lignin from a plant-based biomass in a solvent containing an organic solvent, or a solution (ii) in which solid lignin is dissolved in a solvent containing an organic solvent is used. Can be mentioned.

Examples of the raw material lignin solution (i) include those in which plant-based biomass is separated by an existing method and the lignin contained in the biomass is solubilized in a solvent containing an organic solvent. It can be done and is not particularly limited. For example, a method for treating plant biomass in a mixed solvent of water and an aliphatic alcohol having 4 to 10 carbon atoms described in International Publication No. 2014/142289, and water described in Japanese Patent No. 5256679. A method for treating plant-based biomass according to the above can be mentioned.

For example, as a specific example of the method for obtaining the raw material lignin solution (i) of the present application, a plant-based biomass is mixed with a mixed solvent of water and an aliphatic alcohol (a solvent containing an organic solvent). Lignin can be separated by treatment under conditions of specific charge concentration, specific reaction temperature and time. Here, the concentration of the plant-based biomass charged to the solvent containing the organic solvent is preferably 1% by mass or more and 50% by mass or less, more preferably 3% by mass or more and 20% by mass or less, and further preferably 5% by mass or more and 18% by mass. % Or less. When the concentration of plant-based biomass is 1% by mass or more, the energy efficiency of the process of solubilizing lignin is kept good. On the other hand, if the concentration of plant-based biomass exceeds 50% by mass, the amount of solvent is insufficient and the separation efficiency of lignin decreases.
The treatment reaction temperature is preferably 100 ° C. or higher and 350 ° C. or lower, more preferably 150 ° C. or higher and 300 ° C. or lower, and further preferably 170 ° C. or higher and 270 ° C. or lower. When the temperature is 100 ° C. or higher, the separation of lignin is promoted, and when the temperature exceeds 350 ° C., the formation of cork due to the decomposition of cellulose and the repolymerization of lignin can be suppressed.
The treatment reaction time is 0.1 hour or more and 10 hours or less, preferably 0.2 hours or more and 8 hours or less, more preferably 1 hour or more and 6 hours or less, and further preferably 1 hour or more. It is less than 3 hours. If it is 0.1 hours or more, the separation of lignin proceeds sufficiently, and if it is within 10 hours, the formation of cork due to the decomposition of cellulose and the repolymerization of lignin can be suppressed.

When the raw material lignin solution is the above solution (ii), any solid lignin can be used, and there is no particular limitation. For example, solid lignin obtained by solubilizing lignin from the above-mentioned plant biomass and then concentrating it, solid lignin obtained from black liquor produced in the pulp production process, cellulose and in the process of saccharifying plant biomass. The remaining residue from which sugar has been extracted by hydrolyzing hemicellulose can be used.

The organic solvent is not particularly limited, but may be either saturated or unsaturated, selected from linear alcohols and branched alcohols. In addition, ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran, ethylene glycol and polyethylene glycol may be used. Further, the organic solvent may be used alone or in combination of two or more.
Among them, at least one selected from methanol, ethanol, propanol, 1-butanol, 2-methyl-1-propanol, 2-butanol, 2-methyl-2-propanol, pentanol, hexanol, heptanol, octanol, acetone and tetrahydrofuran. Is preferable, and one or more selected from 1-butanol, 2-methyl-1-propanol, 2-butanol, ethanol, pentanol, hexanol and acetone is more preferable, and 1-butanol and 2-methyl-1- It is more preferably at least one selected from propanol, 2-butanol, ethanol and acetone, further preferably 1-butanol, 2-methyl-1-propanol and 2-butanol, and 1-butanol. Is particularly preferable. Examples of the solvent containing the organic solvent include a mixed solvent of these organic solvents and, for example, water.

The raw material lignin solution preferably has a lignin concentration of 1% by mass or more and 90% by mass or less at 25 ° C. in an organic solvent.
If the concentration of lignin at 25 ° C. is less than 1% by mass, the energy efficiency of the heat-resistant lignin production process deteriorates, which is not preferable. If the concentration of lignin at 25 ° C. exceeds 90% by mass, the degree of purification in the subsequent step (I) is inferior, which is not preferable.
The concentration of lignin at 25 ° C. is preferably 1% by mass or more and 70% by mass or less, more preferably 1% by mass or more and 50% by mass or less, still more preferably 2% by mass or more and 40% by mass or less, and particularly preferably 4% by mass or more. It is 30% by mass or less. When a plurality of kinds of organic solvents are used, the concentration of the lignin means the concentration in the total amount of the organic solvents.

前記炭化水素の双極子モーメントは、好ましくは０．２３ｄ以下であり、より好ましくは０．２０ｄ以下である。[Step (I)]
In the step (I) of the present embodiment, at least selected from the raw material lignin solution, water having a volume of 1 to 50 times or less the volume of the raw material lignin solution, and a hydrocarbon having a dipole moment of 0.25 d or less. Mix with one solvent (a). The step (I) corresponds to a step of purifying lignin in the raw material lignin solution. By going through this treatment step, heat-resistant lignin having excellent heat resistance can be obtained.
As the water, for example, tap water, industrial water, ion-exchanged water, distilled water and the like can be used.
As the hydrocarbon having a dipole moment of 0.25d or less, a saturated chain hydrocarbon, an unsaturated chain hydrocarbon, a saturated ring hydrocarbon or an unsaturated ring hydrocarbon having 5 to 8 carbon atoms is preferable. .. If the dipole moment of the hydrocarbon exceeds 0.25d, the purification efficiency is lowered and lignin having high heat resistance cannot be obtained, which is not preferable. Here, the "dipole moment" is a value calculated by Winmostar MOPAC AMI (MOP6W70). An example of a compound that can be used as such a hydrocarbon is shown below together with its dipole moment value.

The dipole moment of the hydrocarbon is preferably 0.23d or less, more preferably 0.20d or less.

When the amount of water and at least one solvent (a) selected from hydrocarbons having a dipole moment of 0.25 d or less when mixed with the raw material lignin solution is less than 1 times by volume, the raw material lignin solution contains it. It is not possible to sufficiently remove the light components. On the other hand, if the amount of the solvent (a) exceeds 50 times by volume, the desired heat-resistant lignin cannot be efficiently recovered due to an increase in wastewater, an increase in the amount of hydrocarbons used, and the like. When a plurality of types of hydrocarbon solvents are used, the amount of the solvent (a) means the total amount of water and the plurality of types of hydrocarbon solvents.

The amount of the solvent (a) to be mixed with the raw material lignin solution is preferably 1 time or more and 40 times or less, more preferably 1 time or more and 30 times or less, and further preferably 2 times or more and 20 times the volume of the raw material lignin solution. It is twice or less, particularly preferably twice or more and 15 times or less.
The mixing method is not particularly limited as long as the lignin-resin-containing solution and the solvent (a) can be uniformly mixed. The equipment used for mixing includes, for example, an edge runner, a stirring mixer, a roll mill, a cone mill, a flat stone mill, a speed line mill, a ball mill, a bead mill, a sand grind mill, a pearl mill, an attritor, a vertical mixer, a kneader, and a high-speed stirring. Machines (dissolvers) and the like can be mentioned.

By going through this step (I), the lignin in the raw material lignin solution can be purified to obtain heat-resistant lignin.
Specifically, in the step (I), the light component contained in the raw material lignin solution can be removed. Examples of the light component include phenols such as vanillin and sugar peroxidants such as furfural, but are not particularly limited.

The solution temperature in the above step (I) of mixing the raw material lignin solution with water and at least one solvent (a) selected from hydrocarbons having a dipole moment of 0.25 d or less is the stability of the solution and the lignin. Considering the solubility in a solution and the like, the temperature is preferably 0 ° C. or higher and 100 ° C. or lower. The solution temperature is more preferably 10 ° C. or higher and 90 ° C. or lower, further preferably 20 ° C. or higher and 80 ° C. or lower, and particularly preferably 25 ° C. or higher and 70 ° C. or lower.

Further, when mixing the raw material lignin solution and at least one solvent (a) selected from water and a hydrocarbon having a dipole moment of 0.25 d or less in the step (I), stirring is necessary. You may go. When stirring is performed, static separation may be further performed if necessary. The standing time is usually 1 minute or more and 120 minutes or less. If the standing time is 1 minute or more, the thermostable lignin and other light components can be sufficiently separated. Further, the upper limit of the standing time is 120 minutes, which is sufficient. The standing time is preferably 5 minutes or more and 100 minutes or less, more preferably 10 minutes or more and 60 minutes or less, and further preferably 15 minutes or more and 30 minutes or less.

[Step (II-1) or (II-2)]
In the present embodiment, it is preferable to carry out the following step (II-1) or (II-2) depending on whether the solution obtained in step (I) is two-phase or one-phase.
When the solution obtained in the step (I) is two-phase, it is preferable to carry out the step (II-1) in succession after the step (I). In the step (II-1), the phase containing the heat-resistant lignin obtained in the step (I) is separated from the above two phases, the separated phases are concentrated, and then the obtained solid content is dried. For example, when the solution obtained in step (I) is divided into two phases, an aqueous phase and an organic phase, or an aqueous phase and a hydrocarbon phase having an organic phase and a dipole moment of 0.25 d or less. Since the target heat-resistant lignin is dissolved in the organic phase side, the organic phase side is separated in step (II-1), the organic phase side is concentrated, and then the obtained solid content is dried. .. Here, the "organic phase side" is separated from the aqueous phase when a hydrocarbon phase having a dipole moment of 0.25 d or less and an organic phase containing heat-resistant lignin form a single phase. It means a single phase including the above organic phase. Of course, when separated into two phases, an aqueous phase and an organic phase, the "organic phase side" means the organic phase. When the solution obtained in step (I) is divided into two phases, a hydrocarbon phase having a dipole moment of 0.25d or less and an organic phase (an organic phase other than the hydrocarbon), it becomes an organic phase. Since the desired heat-resistant lignin is dissolved, in step (II-1), the organic phase is separated, the organic phase is concentrated, and then the obtained solid content is dried. When the solid content is generated in the two-phase state, the organic phase (side) is separated after the solid-liquid separation.
When the solution obtained in step (I) is one-phase, that is, when the thermostable lignin precipitates as a solid, it is preferable to continue step (II-2). In step (II-2), the solution is solid-liquid separated and the obtained solid is dried.
If the solution obtained in step (I) is two-phase, the light component can be removed from the raw material lignin solution by separating the solution in step (II-1). When the solution obtained in the step (I) is one-phase, the light component can be removed from the raw material lignin solution by solid-liquid separation of the solid precipitated due to the difference in solubility.

<Heat-resistant lignin>
The heat-resistant lignin obtained by the production method of the present embodiment described above has the following physical characteristics:
_{(1) The glass transition temperature T g} by the dynamic viscoelasticity measurement method (DMA method) is 70 ° C. or higher.
(2) The number average molecular weight is 600 or more, and (3) the 5% thermogravimetric reduction start temperature in the differential thermal and thermogravimetric simultaneous measurement (TG-DTA measurement) is 210 ° C. or more.

The heat-resistant lignin obtained by the production method of the present embodiment has a glass transition temperature T _g of 70 ° C. or higher, preferably 75 ° C. or higher, more preferably 80 ° C. or higher, further preferably 80 ° C. or higher by the dynamic viscoelasticity measurement (DMA) method. It is preferably 85 ° C. or higher. When the glass transition temperature T _g is in the above range, lignin having excellent heat resistance can be obtained.

The number average molecular weight (Mn) of the heat-resistant lignin obtained by the production method of the present embodiment is 600 or more. Such a number average molecular weight can be obtained by measurement by gel permeation chromatography (GPC) using polystyrene as a conversion standard. According to the production method of the present embodiment, since the lignin content having a low molecular weight can be cut, the degree of purification of lignin is increased, and lignin having excellent heat resistance can be obtained. The number average molecular weight of the thermostable lignin is preferably 630 or more, more preferably 650 or more.

In the present embodiment, the 5% thermogravimetric reduction start temperature in the TG-DTA measurement of the heat-resistant lignin is 210 ° C. or higher, so that it can be seen that the heat-resistant lignin has high heat resistance. The 5% thermogravimetric reduction start temperature is more preferably 230 ° C. or higher.

The heat-resistant lignin obtained by the production method of the present embodiment preferably further satisfies the following requirements (4) and (5).
(4) In the integrated molecular weight distribution curve obtained by gel permeation chromatography (GPC) using polystyrene as a conversion standard, the proportion of constituents having a molecular weight of 320 or less is 15% or less, and (5) polystyrene is used as a conversion standard. In the integrated molecular weight distribution curve obtained by the gel permeation chromatography (GPC), the proportion of the constituent components having a molecular weight of 3200 or more is 7% or more and 50% or less.

In this embodiment, the molecular weight of lignin is obtained by measurement by gel permeation chromatography (GPC) using polystyrene as a conversion standard. The polystyrene-equivalent molecular weight of 320 or less and the polystyrene-equivalent molecular weight of 3200 or more were determined from the peak area in the integrated molecular weight distribution curve obtained by GPC.
In the integrated molecular weight distribution curve obtained by GPC, the ratio of the constituent components of the heat-resistant lignin having a molecular weight of 320 or less is 15% or less. Since the proportion of constituents having a molecular weight of 320 or less is 15% or less, there are few monocyclic phenols (light components) having a small molecular weight. The proportion of the constituents having a molecular weight of 320 or less is preferably 11% or less, more preferably 8% or less, still more preferably 5% or less.
Further, the heat-resistant lignin has a molecular weight of 3200 or more as determined from the integrated molecular weight distribution curve obtained by GPC, and the proportion of the constituent components is 7% or more and 50% or less. If the proportion of the constituent components having a molecular weight of 3200 or more is less than 7%, the heat resistance is inferior, which is not preferable. Further, if the proportion of the constituent components having a molecular weight of 3200 or more exceeds 50%, the moldability is inferior, which is not preferable. The proportion of the constituent components having a molecular weight of 3200 or more is preferably 10% or more and 50% or less, and more preferably 10% or more and 30% or less.

The heat-resistant lignin obtained by the production method of the present embodiment (hereinafter, may be abbreviated as heat-resistant lignin) may be soluble in an organic solvent and a mixed solvent of an organic solvent and water. The organic solvent is not particularly limited, and examples thereof include alcohols such as methanol, ethanol and butanol, ethers such as dimethyl ether, diethyl ether and tetrahydrofuran, and ketone compounds such as acetone. In particular, it is highly soluble in tetrahydrofuran, acetone (and a mixed solvent with water) and is completely soluble at room temperature.

The amount of 1-butanol reacted with lignin of the heat-resistant lignin obtained by the production method of the present embodiment is preferably 10 wt% or less, more preferably 5 wt% or less, still more preferably 2.5 wt% or less, and particularly preferably 1 wt%. It is as follows. If it exceeds 10 wt%, if a considerable amount of lignin cannot be added to a higher value than 1-butanol, the cost for 1-butanol loss will increase, which is not preferable in terms of reducing economic efficiency. The lower limit is not particularly limited, but is usually 0.1 wt% or more.

The amount of 1-butanol that has reacted with lignin can be measured, for example, by the following method.
The lignin obtained by replacing 1-butanol used in the production method of the present embodiment with 1-butanol-d ₁₀ ^{and treating it with 2} H-NMR was analyzed to react with lignin. -The amount of butanol can be calculated. In order to quantify the amount of 1-butanol that has reacted with lignin, 3- (trimethylsilyl) -1-propanesulfonic acid-d ₆ sodium salt is added to lignin ^{as an internal standard, and 2 1} H-NMR measurement is performed.

(1) ² 1 H-NMR measurement conditions NMR device: DRX500 manufactured by Bruker Biospin Co., Ltd.
Probe: TCI 5φ cryoprobe Resonance frequency: 76.77MHz
Observation range: -2.5 to 12.5 ppm
Observation center: 5.00ppm
aquistion time: 2.11 seconds
relaxation delay: 5.0 seconds Flip angle: 30 °
Pulse width: 200 microseconds NMR sample tube: 5φ
Sample amount: 5 to 15 mg
Solvent: Dimethylsulfoxide Measurement temperature: Room temperature Number of integrations: 10,000 times (2) Method of assigning the amount of 1-butanol that reacted with lignin 1-butanol _{was replaced with 1-butanol-d 10} to obtain lignin. , 1-butanol -d _10, 3- (trimethylsilyl) -1-propanesulfonic acid -d ₆ sodium salt, from a comparison of the ² H-NMR spectra of these three samples, was observed in δ3.8~4.0ppm The peak is attributed to the peak derived from 1-butanol-d _{10 that reacted with lignin.} From the observed range, it is inferred that the aromatic hydroxyl group in lignin _{reacts with 1-butanol-d-10} to form an aromatic ether bond.

(3) Method for quantifying 1-butanol-d ₁₀ (wt%) that reacted with lignin A: Weighed value of lignin (mg)
B: Weighed value of 3- (trimethylsilyl) -1-propanesulfonic acid-d ₆ sodium salt (mg)
C: Integrated value derived from 1-butanol that reacted with lignin observed around δ3.8 to 4.0 ppm D: 3- (trimethylsilyl) -1-propanesulfonic acid observed around δ0.3 to 0.5 ppm -D _{Integral value derived from 6-} sodium salt E: 3- (trimethylsilyl) -1-propanesulfonic acid-d _{Purity of 6-} sodium salt F: 3- (trimethylsilyl) -1-propanesulfonic acid-d Mormomatic mass of _{6-sodium salt} a = B × E / (F × 100,000)
b = a × F × 1000 × C / 2
1-butanol-d ₁₀ amount (wt%) that reacted with lignin = 100 x b / A

<Use of heat-resistant lignin>
The heat-resistant lignin obtained by the production method according to the present embodiment can be used alone in the fields of application in which phenol resins have been used so far. It is also possible to produce a resin composition by blending the heat-resistant lignin according to the present embodiment with another phenol resin.
Further, since the heat-resistant lignin obtained by the production method according to the present embodiment has a small amount of sulfur compounds and other light components, it can be made into an epoxy modified product by a known reaction for introducing an epoxy group. The heat-resistant lignin modified with epoxy in this way can be applied to application fields in which epoxy resins have been used so far.
Further, the heat-resistant lignin obtained by the production method according to the present embodiment can be used as an additive for a thermoplastic resin.
In the present embodiment, the heat-resistant lignin can also be applied as a base resin raw material for a phenol resin or an epoxy resin, an epoxy resin additive (curing agent), a thermoplastic resin additive, or the like. This is due to the characteristic that thermostable lignin has a phenolic structural unit. The heat-resistant lignin according to the present embodiment can be used in combination with a curing agent such as an acid anhydride known to those skilled in the art.

Since the heat-resistant lignin obtained in the present embodiment has few light components (low molecular weight components), it can be used as a raw material and an additive for the base resin.
For use as a base resin raw material, a conventionally known method can be used. One example is a resin composition in which lignin and a known cross-linking agent typified by hexamethylenetetramine are blended.
Various fillers and industrially obtained general phenol resins may be added to the resin composition in which the lignin and the cross-linking agent are mixed, if necessary.
Regarding the use as an additive, for example, conventionally known methods listed in JP-A-2014-15579, International Publication No. 2016/104634 and the like can be used. Various additives and fillers may be added to the resin composition in which the lignin and the thermoplastic resin are mixed, if necessary.

[Resin composition]
In the present invention, two embodiments can be mentioned for the resin composition containing lignin. The details will be described below.
The resin composition according to the first embodiment contains the above-mentioned heat-resistant lignin. Further, in addition to the above-mentioned heat-resistant lignin, a resin component such as a thermoplastic resin or a thermosetting resin may be contained. The method for producing the resin composition in the present embodiment is not particularly limited, and the resin composition can be obtained by appropriately mixing the above-mentioned heat-resistant lignin with other resin components.
Ingredients other than heat-resistant lignin will be described below.

<Thermoplastic resin>
The thermoplastic resin that can be blended in the resin composition according to the present embodiment is an amorphous thermoplastic resin having a glass transition temperature of 200 ° C. or lower, or a crystalline thermoplastic resin having a melting point of 200 ° C. or lower. Is preferable. Examples of the thermoplastic resin include polycarbonate resins, styrene resins, polystyrene elastomers, polyethylene resins, polypropylene resins, polyacrylic resins (polymethyl methacrylate resins, etc.), polyvinyl chloride resins, cellulose acetate resins, and polyamide resins. Low melting point polyester resin (PET, PBT, etc.) typified by a combination of terephthalic acid and ethylene glycol, terephthalic acid and 1,4-butanediol, polylactic acid and / or a copolymer containing polylactic acid, acrylonitrile-butadiene -Stylene resin (ABS resin), polyphenylene oxide resin (PPO), polyketone resin, polysulfone resin, polyphenylene sulfide resin (PPS), fluororesin, silicon resin, polyimide resin, polybenzimidazole resin, polyamide elastomer, etc., and others. Examples of the copolymer with the monomer of.
The resin composition according to the present embodiment may contain a resin, an additive, and a filler compatible with the thermoplastic resin composition, in addition to the above-mentioned cellulose-containing solid substance and thermoplastic resin.

<Thermosetting resin>
The thermosetting resin that can be blended in the resin composition according to the present embodiment is not particularly limited. For example, examples of the phenol resin include a novolak-based phenol resin and a resol-based phenol resin, which may be used alone or in combination. Further, other general thermosetting resins such as epoxy resin, polyurethane resin, melamine resin, urea resin, unsaturated polyester resin, silicone resin, and alkyd resin can also be used.
Like lignin, it has a phenolic hydroxyl group, can react with lignin, and can be used as a diluent for lignin. Therefore, it is preferable to use a phenol resin among the above thermosetting resins. ..

As a thermosetting resin that can be blended in the resin composition according to the present embodiment, a lignin-reactive compound having a functional group capable of reacting with lignin may be blended. Examples of the compound having a functional group capable of reacting with lignin include (e) a compound that causes an electrophilic substitution reaction with a phenol compound, (f) a compound having an epoxy group, and (g) a compound having an isocyanate group. These thermosetting resins (e) to (g) may be blended together with the above-mentioned phenol resin in consideration of physical properties such as processability of the resin composition, strength of the molded product, and heat resistance.
Since lignin has a phenolic structural unit, it can be applied as a base resin raw material such as a phenol resin and an epoxy resin, an additive (hardener) for an epoxy resin, and the like.

(E) Compound that causes an electrophilic substitution reaction with a phenol compound Examples of the compound that causes an electrophilic substitution reaction with a phenol compound include formaldehyde, a formaldehyde donating curing agent compound, and a formaldehyde equivalent compound. Commercially, hexamethylenetetramine, hexaformaldehyde, and paraformaldehyde can be used.

(F) Compound having an epoxy group A compound having an epoxy group belongs to the category of so-called epoxy resin. Examples include 2,2-bis (4-hydroxyphenyl) propane (called bisphenol A), bis (2-hydroxyphenyl) methane (called bisphenol F), and 4,4'-dihydroxydiphenylsulfone. (Called bisphenol S), 4,4'-dihydroxybiphenyl, resorcin, saligenin, trihydroxydiphenyldimethylmethane, tetraphenylol ethane, these halogen and alkyl group substituents, butanediol, ethylene glycol, erythritol , Novolac, glycerin, polyoxyalkylene and other compounds containing two or more hydroxyl groups in the molecule and glycidyl ether epoxy resin synthesized from epichlorohydrin and the like; containing two or more of the hydroxyl groups in the molecule Glycidyl ester epoxy resin synthesized from compounds and phthalic acid glycidyl ester, etc .; synthesized from primary amines such as aniline, diaminodiphenylmethane, metaxylene diamine, 1,3-bisaminomethylcyclohexane, etc. or secondary amines and epichlorohydrin, etc. Epoxy resins containing glycidyl groups such as glycidylamine-based epoxy resins; epoxy resins containing no glycidyl groups such as epoxidized soybean oil, epoxidized polyolefins, vinylcyclohexendioxides, and dicyclopentadiendioxides can be mentioned. Among these, cresol novolac type and phenol novolac type epoxy resins having similar chemical structures to lignin and good compatibility are preferable.

When the lignin contained in the thermosetting resin composition according to the present embodiment is a compound containing an epoxy group, a curing accelerator can be appropriately added depending on the purpose of accelerating the curing reaction. Specific examples include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, and 1,8-diazabicyclo (5,4,0). Tertiary amines such as undecene-7, phosphines such as triphenylphosphine, quaternary ammonium salts such as tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecanylammonium salt, cetyltrimethylammonium salt, triphenylbenzyl Examples thereof include quaternary phosphonium salts such as phosphonium salt, triphenylethylphosphonium salt and tetrabutylphosphonium salt, and metal compounds such as tin octylate. Examples of the counter ion of the quaternary phosphonium salt include halogen, organic acid ion, hydroxide ion and the like, and organic acid ion and hydroxide ion are particularly preferable.

(G) Compound having an isocyanate group Examples of the compound having an isocyanate group include polyisocyanate or a compound obtained by reacting polyisocyanate with a polyol. Examples of the polyisocyanate include aromatic polyisocyanates such as tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), polypeptide MDI (MDI-CR), and carbodiimide-modified MDI (liquid MDI), and norbornan diisocyanate (NBDI). ), Isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), 4,4'-methylene-bis (cyclohexyl isocyanate) (hydrogenated MDI), xylylene diisocyanate (XDI) and other aliphatic polyisocyanates, and blocked isocyanate. Can be mentioned. Among these, it is preferable to use toluene diisocyanate (TDI) and 4,4'-diphenylmethane diisocyanate (MDI).

A curing accelerator can be appropriately added to the resin composition according to the present embodiment according to the purpose of accelerating the curing reaction. Examples of the curing accelerator include organometallic catalysts of zirconium and aluminum, dibutyltin laurate, phenol salts of DBU, octylates, amines, imidazoles, etc., but in terms of colorability, organometallic catalysts, etc. For example, aluminum sec-butyrate, aluminum ethyl acetoacetate diisopropylate, zirconium tributoxyacetyl acetonate, zirconium tetraacetyl acetonate and the like are particularly preferable.

<Other resin components>
In addition to lignin, the resin composition according to the present embodiment may contain resins such as urea resin, melamine resin, silicone resin, unsaturated polyester resin, alkyd resin, and polyurethane resin.

<Inorganic filler, organic filler>
The resin composition according to the present embodiment may contain a filler. The filler may be an inorganic filler or an organic filler.
Examples of the inorganic filler include spherical or crushed molten silica, silica powder such as crystalline silica, alumina powder, glass powder, glass fiber, glass flakes, mica, talc, calcium carbonate, alumina, hydrated alumina, and silicon nitride. Examples thereof include boron, aluminum nitride, silicon nitride, silicon carbide, titanium nitride, zinc oxide, tungsten carbide, magnesium oxide and the like.
Examples of the organic filler include carbon fiber, aramid fiber, paper powder, cellulose fiber, cellulose powder, paddy shell powder, fruit shell / nut powder, chitin powder, starch and the like.
The inorganic filler and the organic filler may be contained alone or in a combination of two or more, and the content thereof is determined according to the purpose. When the inorganic filler and / or the organic filler is contained, it is desirable that the content of the inorganic filler and / or the organic filler is an appropriate amount in order to obtain good physical properties and moldability.

<Other additives>
Various additives can be added to the resin composition according to the present embodiment as long as the characteristics of the molded product obtained from the resin composition are not impaired. Further, a compatibilizer, a surfactant and the like can be further added depending on the purpose.
As the compatibilizer used together with the thermoplastic resin, a resin obtained by adding maleic anhydride, epoxy, etc. to the thermoplastic resin and introducing a polar group, for example, a maleic anhydride-modified polyethylene resin, a maleic anhydride-modified polypropylene resin, and various commercially available phases. A solubilizer may be used in combination.
Further, examples of the surfactant include linear fatty acids such as stearic acid, palmitic acid and oleic acid, and branched / cyclic fatty acids with rosins, but the surfactant is not particularly limited thereto.
Further, as additives that can be blended in addition to the above-mentioned ones, flexible agents, heat stabilizers, ultraviolet absorbers, flame retardants, antistatic agents, antifoaming agents, thixotropy-imparting agents, mold release agents, antioxidants, etc. Agents, plasticizers, low stress agents, coupling agents, dyes, light scatterers, small amounts of thermoplastics and the like.

<Resin molded product>
A molded product can be obtained from the above resin composition containing heat-resistant lignin.
The method of molding into a predetermined shape is not particularly limited as long as the resin composition can be molded. For example, when the resin composition is a thermosetting resin composition, examples of the method for molding into a predetermined shape include a compression molding method, an injection molding method, a transfer molding method, a medium-sized molding method, and an FRP molding method. When the resin composition is a thermoplastic resin composition, examples of the method for molding into a predetermined shape include an extrusion molding method and an injection molding method.

Examples of molded products include a cured resin composition in which a heat-resistant lignin and a cross-linking agent are blended, and various fillers and industrially obtained general phenol resins are blended as necessary. Examples thereof include those which are molded into a predetermined shape and then cured, those which are cured and then molded, and those in which a resin composition obtained by mixing heat-resistant lignin with a thermoplastic resin is molded. Molded products of such resin compositions include heat insulating materials for houses, electronic parts, resins for flax sands, resins for coated sands, resins for impregnation, resins for lamination, resins for FRP molding, automobile parts, and reinforcement of automobile tires. It can be used for materials, OA equipment, machines, information and communication equipment, industrial materials, and the like.

The resin composition in the second embodiment has the following steps:
A step (IA) of adding a resin to a raw material lignin solution to obtain a lignin-resin-containing solution, and
At least one solvent selected from the above-mentioned lignin-resin-containing solution and hydrocarbons having a volume of 1 to 50 times or less of the lignin-resin-containing solution and a dipole moment of 0.25 d or less. Step of mixing with (a') (IB)
It is a lignin-containing resin composition obtained by the method including.
The raw material lignin solution is as described above. That is, a lignin solution (i) obtained by solubilizing lignin from a plant-based biomass in a solvent containing an organic solvent, or a solution (ii) in which solid lignin is dissolved in a solvent containing an organic solvent can be mentioned. , Details, preferred embodiments, etc. are the same.
The amount of the resin compounded in the above step (IA) is usually 10 to 2000 with respect to 100 parts by mass of the lignin solid content of the raw material lignin solution from the viewpoint of obtaining a lignin-containing resin composition having high strength. It is by mass, more preferably 20 to 1000 parts by mass, and even more preferably 50 to 500 parts by mass.

The resin used in the step (IA) is not particularly limited as long as it is a resin that dissolves in the raw material lignin solution, and may be a thermosetting resin or a thermoplastic resin. The resin components are as described above, and the preferred ones for each resin component are also the same. Considering a molding method for molding a molded product having a suitable use for a lignin-containing resin composition, it is more preferable to use a thermosetting resin.
As the resin used in the step (IA), for example, a phenol resin such as the above-mentioned novolak-based phenol resin or resol-based phenol resin can be used. Further, other general thermosetting resins and thermoplastic resins described above can also be used.
Like lignin, it has a phenolic hydroxyl group, can react with lignin, and can be used as a diluent for lignin. Therefore, phenol resin is preferable among the above resins, and novolak-based phenol resin and resole. At least one phenol resin selected from the group consisting of phenol resins is more preferable.

In the above step (IB), when the amount of at least one solvent (a') selected from hydrocarbons having a dipole moment of 0.25 d or less is less than 1 in volume, the lignin-containing resin composition is used. Light components derived from the raw material lignin solution cannot be sufficiently removed. On the other hand, if the amount of the solvent (a') exceeds 50 times by volume, the desired heat-resistant lignin cannot be efficiently recovered due to an increase in wastewater, an increase in the amount of hydrocarbons used, and the like. When a plurality of types of hydrocarbon solvents are used, the amount of the solvent (a') means the total amount of water and the plurality of types of hydrocarbon solvents.
At least one solvent (a') of the solvent selected from water and hydrocarbons having a dipole moment of 0.25 d or less used in the step (IB) is the same as the solvent (a) described above. The amount of the solvent (a') with respect to the lignin-resin-containing solution is preferably 1 time or more and 40 times or less, more preferably 1 time or more and 30 times or less, still more preferably 2 times or more and 20 times or less, and particularly preferably 2 times. It is more than double and 15 times or less.

The solution temperature in the step (IB) of mixing the lignin-resin-containing solution with at least one solvent (a') of a solvent selected from water and hydrocarbons having a dipole moment of 0.25 d or less is stable. It is preferably 0 ° C. or higher and 100 ° C. or lower in consideration of properties, solubility of lignin in a solution, and the like. The solution temperature is more preferably 10 ° C. or higher and 90 ° C. or lower, further preferably 20 ° C. or higher and 80 ° C. or lower, and particularly preferably 25 ° C. or higher and 70 ° C. or lower.
The mixing method is not particularly limited as long as the lignin-resin-containing solution and the solvent (a') can be uniformly mixed. The equipment used for mixing includes, for example, an edge runner, a stirring mixer, a roll mill, a cone mill, a flat stone mill, a speed line mill, a ball mill, a bead mill, a sand grind mill, a pearl mill, an attritor, a vertical mixer, a kneader, and a high-speed stirring. Machines (dissolvers) and the like can be mentioned.

Further, when mixing the lignin-resin-containing solution and at least one solvent (a') selected from water and a hydrocarbon having a dipole moment of 0.25 d or less in the step (IB), if necessary. May be stirred. When stirring is performed, static separation may be further performed if necessary. The standing time is usually 1 minute or more and 120 minutes or less. When the standing time is 1 minute or more, other light components derived from the raw material lignin solution can be sufficiently separated from the lignin-containing resin composition. Further, the upper limit of the standing time is 120 minutes, which is sufficient. The standing time is preferably 5 minutes or more and 100 minutes or less, more preferably 10 minutes or more and 60 minutes or less, and further preferably 15 minutes or more and 30 minutes or less.

By going through the step (IB), the light component can be separated from the lignin contained in the lignin-resin-containing solution. Examples of the light component include phenols such as vanillin and sugar peroxidants such as furfural, but are not particularly limited.

In the second embodiment, it is preferable to carry out the following step (IIA) or (IIB) depending on whether the mixed solution obtained by the step (IB) is two-phase or one-phase.
When the solution obtained by the step (IB) is two-phase, it is preferable to carry out the step (IIA) in succession. In the step (IIA), the phase containing the heat-resistant lignin obtained in the step (IB) is separated from the above two phases, the separated phases are concentrated, and then the obtained solid content is dried. For example, when the solution obtained by the step (IB) is divided into two phases, an aqueous phase and an organic phase, or an aqueous phase and a hydrocarbon phase having an organic phase and a dipole moment of 0.25 d or less. Since the target heat-resistant lignin is dissolved in the organic phase side, the organic phase side is separated in the step (IIA), the organic phase side is concentrated, and then the obtained solid content is dried. Here, the "organic phase side" is separated from the aqueous phase when a hydrocarbon phase having a dipole moment of 0.25 d or less and an organic phase containing heat-resistant lignin form a single phase. It means a single phase including the above organic phase. Of course, when separated into two phases, an aqueous phase and an organic phase, the "organic phase side" means the organic phase. When the solution obtained in the step (IB) is divided into two phases, a hydrocarbon phase having a dipole moment of 0.25 d or less and an organic phase (an organic phase other than the hydrocarbon), the solution becomes an organic phase. Since the desired heat resistant lignin is dissolved, in step (IIA), the organic phase is separated, the organic phase is concentrated, and then the obtained solid content is dried. When the solid content is generated in the two-phase state, the organic phase (side) is separated after the solid-liquid separation.

When the solution obtained by the step (IB) is one phase, that is, when the target lignin-containing resin composition precipitates as a solid, it is preferable to continue the step (IIB). In step (IIB), the solution is solid-liquid separated and the resulting solid is dried.
If the solution obtained in the step (IB) is two-phase, the light component can be removed from the lignin-containing resin composition by separating the solutions in the step (IIA). When the solution obtained in the step (IB) is one-phase, the light component can be removed from the lignin-containing resin composition by solid-liquid separation of the solid precipitated due to the difference in solubility.

The lignin-reactive compound, curing accelerator, inorganic filler, organic filler and other additives that can be used in the method for producing a lignin-containing resin composition according to the second embodiment of the present invention are the first of the present invention. It is the same as that which can be used in the lignin-containing resin composition according to the first embodiment.
The above-mentioned lignin-reactive compound or the like may be added together with the resin in the step (IA), or the above-mentioned lignin-reactive compound or the like may be added between the step (IA) and the step (IB) described later. A process may be provided. Alternatively, the above-mentioned lignin-reactive compound or the like may be added after the step (IIA) or the step (IIB).

The molded article, molding method, and use thereof using the lignin-containing resin composition according to the second embodiment are the same as those of the lignin-containing resin composition according to the first embodiment, and are as described above.

Hereinafter, the present embodiment will be described in more detail with reference to Examples, but the present embodiment is not limited thereto.

Manufacturing example 1
As a raw material, bagasse (sample size 3 mm square or less) and a mixed solvent of water and 1-butanol, which is an organic solvent (prepared so that water / 1-butanol = 8/1 in molar ratio), have an internal volume of 0. Placed in a .92 L SUS batch device. The mass of the mixed solvent composed of water and butanol was 300 g. The bagasse charge concentration was 10% by mass in terms of mass ratio with respect to the above mixed solvent.
After purging the inside of the SUS batch type apparatus with nitrogen, the temperature was raised to 200 ° C., and the decomposition reaction was carried out at a reaction temperature of 200 ° C. for 2 hours. The reaction time was defined as the elapsed time after reaching 200 ° C. In addition, the temperature was measured with a thermocouple. The internal pressure during the reaction was 1.9 MPa.
After completion of the treatment, the SUS batch type apparatus was cooled to around room temperature, and then all the contents were taken out and filtered to separate the biomass residue and the liquid phase. Further, the aqueous phase of the filtrate and the 1-butanol phase were liquid / liquid separated by a separating funnel. The separated 1-butanol phase was used as the raw material lignin solution. The solid content (lignin) concentration was 50 g / L-butanol phase when the butanol phase was separately concentrated and determined.

Manufacturing example 2
As a raw material, bagasse (sample size 3 mm square or less) and a mixed solvent of water and 1-butanol, which is an organic solvent (prepared so that water / 1-butanol = 8/1 in molar ratio), have an internal volume of 0. Placed in a .92 L SUS batch device. The mass of the mixed solvent composed of water and butanol was 300 g. The bagasse charge concentration was 10% by mass in terms of mass ratio with respect to the above mixed solvent.
After purging the inside of the SUS batch type apparatus with nitrogen, the temperature was raised to 200 ° C., and the decomposition reaction was carried out at 200 ° C. for 2 hours. The reaction time was defined as the elapsed time after reaching 200 ° C. In addition, the temperature was measured with a thermocouple. The internal pressure during the reaction was 1.9 MPa.
After completion of the treatment, the SUS batch type apparatus was cooled to around room temperature, and then all the contents were taken out and filtered to separate the biomass residue into a liquid phase. Further, the aqueous phase of the filtrate and the 1-butanol phase were liquid / liquid separated by a separating funnel. The separated butanol phase was concentrated and vacuum dried at 125 ° C. to obtain 6.5 g of a solid (lignin).

Example 1
Add 178 mL of ion-exchanged water to 14 mL of the raw material lignin solution (water + butanol phase) obtained in Production Example 1 (lignin concentration is 6% by mass, 0.7 g of lignin is dissolved in 14 mL of butanol + water mixed solvent). added. The amount of water was 12.7 times that of the raw material lignin solution. The resulting mixed solution was stirred at 25 ° C. for 15 minutes. The liquid phase after stirring was one phase. The solid was filtered off by filtration, and the obtained solid content was dried at 125 ° C.
For the solid matter, the molecular weight, the thermogravimetric reduction start temperature, and the glass transition point were determined. The results are shown in Table 2.

Example 2
To 10 mL of the lignin solution obtained in Production Example 1 (lignin concentration was 6 wt%, 0.5 g of lignin was dissolved in 10 mL of butanol + water mixed solvent), 10 mL of ion-exchanged water was added. The amount of water was 1 times that of the raw material lignin solution. The mixed solution was stirred at 50 ° C. for 15 minutes. The liquid phase after stirring was two phases. The liquid phase was filtered, leaving no solids on the filter paper. The aqueous phase and the butanol phase were separated, the butanol phase was concentrated, and the obtained solid content was dried at 125 ° C. For the solid matter, the molecular weight, the thermogravimetric reduction start temperature, and the glass transition point were determined. The results are shown in Table 2.

Example 3
The same operation as in Example 2 was performed except that the amount of ion-exchanged water was 20 mL. The amount of water was twice that of the raw material lignin solution. The results are shown in Table 2.
Example 4
The same operation as in Example 2 was performed except that the amount of ion-exchanged water was 70 mL. The amount of water was 7 times that of the raw material lignin solution. The results are shown in Table 2.
Example 5
The same operation as in Example 2 was carried out except that the amount of ion-exchanged water was adjusted to 20 mL and the mixture was stirred at 70 ° C. The amount of water was twice that of the raw material lignin solution. The results are shown in Table 2.
Example 6
The same operation as in Example 2 was carried out except that the amount of ion-exchanged water was adjusted to 70 mL and the mixture was stirred at 70 ° C. The amount of water was 7 times that of the raw material lignin solution. The results are shown in Table 2.
Example 7
The same operation as in Example 1 was performed except that the mixture was stirred at 70 ° C. The amount of water was 13 times that of the raw material lignin solution. The results are shown in Table 3.

Example 8
1 g of the solid obtained in Production Example 2 was completely dissolved in 30 mL of acetone. The concentration of lignin in the solution was 4% by weight. To this acetone solution, 30 mL of ion-exchanged water (1 times as much as the raw material lignin solution) was added. The mixed solution was stirred at 25 ° C. for 15 minutes, and the liquid phase after stirring was one phase. The solid was filtered off by filtration, and the obtained solid content was dried at 125 ° C. For the solid matter, the molecular weight, the thermogravimetric reduction start temperature, and the glass transition point were determined. The results are shown in Table 3.
Example 9
The same operation as in Example 8 was performed except that the amount of ion-exchanged water was 60 mL. The amount of water was twice that of the raw material lignin solution. The results are shown in Table 3.
Example 10
The same operation as in Example 8 was performed except that the amount of ion-exchanged water was 90 mL. The amount of water was three times that of the raw material lignin solution. The results are shown in Table 3.
Example 11
140 mL of heptane was added to 14 mL of the lignin solution (water + butanol phase) obtained in Production Example 1 (the concentration of lignin was 6% by mass, 0.7 g of lignin was dissolved in a mixed solvent of 14 mL of butanol + water). The amount of heptane was 10 times that of the raw material lignin solution. The resulting mixed solution was stirred at 25 ° C. for 15 minutes. The liquid phase after stirring was one phase. The solid was filtered off by filtration, and the obtained solid content was dried at 125 ° C. For the solid matter, the molecular weight, the thermogravimetric reduction start temperature, and the glass transition point were determined. The results are shown in Table 3.
Example 12
1 g of the solid obtained in Production Example 2 was completely dissolved in 30 mL of acetone. The concentration of lignin in the solution was 4% by weight. 30 mL of heptane (1 times as much as the raw material lignin solution) was added to this acetone solution. The mixed solution was stirred at 25 ° C. for 15 minutes, and the liquid phase after stirring was one phase. The solid was filtered off by filtration, and the obtained solid content was dried at 125 ° C. For the solid matter, the molecular weight, the thermogravimetric reduction start temperature, and the glass transition point were determined. The results are shown in Table 3.

Comparative Example 1
The molecular weight of the solid itself obtained in Production Example 2, the thermogravimetric reduction start temperature, the glass transition point, and the phenolic OH equivalent were determined. The results are shown in Table 3.

[Evaluation method]
1. 1. Molecular weight: number average molecular weight (Mn), mass average molecular weight (Mw)
The mass average molecular weight (Mw) and the number average molecular weight (Mn) were measured by a gel permeation chromatography (GPC) method using a tetrahydrofuran solvent under the following conditions.
[Measurement condition]
SEC equipment: HLC-8220 GPC (manufactured by Tosoh Corporation)
Column: TSKgel guardcolumn HXL-H + TSKgel GMH-XL 2 + G2000H-XL 1 (manufactured by Tosoh)
Solvent: THF (Wako Pure Chemical Industries, Ltd. Stabilizer-free special grade)
Detector: Differential Refractometer (RI) Detector, UV Detector Concentration: 0.1w / v%
Injection volume: 100 μl
Flow velocity: 1.0 ml / min
Column temperature: 40 ° C
Standard sample for calibration curve: TSK standard polystyrene made by Tosoh Analysis software: GPC-8020model II
A component having a molecular weight of 320 or less in terms of polystyrene and a component having a molecular weight of 3200 or more in terms of polystyrene were determined from the integrated molecular weight distribution curve obtained by the above GPC.
2. Thermogravimetric start temperature (Td5)
The 5% thermogravimetric reduction start temperature (Td5) was measured with EXSTAR6000 TG / DTA6200 manufactured by Seiko Instruments Inc. A sample of about 10 mg was weighed in a Pt pan, and the temperature was measured in the range of a temperature rising rate of 10 ° C./min, a measuring atmosphere: air of 200 mL / min, and a temperature of 35 ° C. to 800 ° C. to determine a temperature at which the weight was reduced by 5%.
3. 3. Glass transition temperature (T _g )
The glass transition temperature (T _g ) was measured by the solid viscoelastic method (DMA method).
Using a press machine, a molded plate of lignin obtained in each Example and Comparative Example was prepared, and a sample of 5 mm × 30 mm × 1 mm was cut out from the molded plate. Measurements were carried out using DMA8000 (manufactured by PerkinElmer Japan Co., Ltd.) under the conditions of a temperature rise temperature of 2 ° C./min and 1 Hz until the temperature reached 0 ° C. to 300 ° C. or the limit minimum elastic modulus. The peak temperature of the obtained tan δ was defined as the glass transition temperature (T _g ).
4. Phenolic hydroxyl group (OH group) equivalent The phenolic hydroxyl group equivalent was determined with reference to the method described in Energy Fuel 2010, 24, 2723.

As can be seen from the examples, lignin having high heat resistance was obtained. Since the lignin of this example has high heat resistance, it is not necessary to carry out secondary denaturation such as secondary derivatization. Moreover, since it has the phenolic hydroxyl group equivalent derived from natural lignin as it is, it can be seen that it can be suitably used as a material.

According to this embodiment, it is possible to provide lignin having high heat resistance without secondary derivatization while maintaining the structure derived from natural lignin.

Claims (8)

A step of mixing the raw material lignin solution with at least one solvent (a) selected from water having a volume of 1 to 50 times that of the raw material lignin solution and a hydrocarbon having a dipole moment of 0.25 d or less (a). the I) only contains,
The solution obtained in step (I) is one phase, and further comprises a step (II-2) of solid-liquid separation of the solution obtained in step (I).
A method for producing heat-resistant lignin. The raw material lignin solution is a lignin solution obtained by solubilizing lignin from a plant-based biomass in a solvent containing an organic solvent, or a solution in which solid lignin is dissolved in a solvent containing an organic solvent, according to claim 1. The method for producing a heat-resistant lignin according to the above. The method for producing a heat-resistant lignin according to claim 2, wherein the organic solvent is at least one selected from alcohols, ethers and ketone compounds. (1) The glass transition temperature Tg by the dynamic viscoelasticity measurement method (DMA method) is 70 ° C. or higher.
(2) The number average molecular weight is 600 or more, and (3) the 5% thermogravimetric reduction start temperature in the differential thermal and thermogravimetric simultaneous measurement (TG-DTA measurement) is 210 ° C. or more, claims 1 to 3. Heat-resistant lignin obtained by the production method according to any one of the above. The heat-resistant lignin according to claim 4 , which further satisfies the following requirements (4) and (5):
(4) In the integrated molecular weight distribution curve obtained by gel permeation chromatography (GPC) using polystyrene as a conversion standard, the proportion of constituents having a molecular weight of 320 or less is 15% or less.
(5) In the integrated molecular weight distribution curve obtained by gel permeation chromatography (GPC) using polystyrene as a conversion standard, the proportion of constituents having a molecular weight of 3200 or more is 7% or more and 50% or less. A resin composition containing the heat-resistant lignin according to claim 4 or 5 , or a molded product using the resin composition. A step (IA) of adding a resin to a raw material lignin solution to obtain a lignin-resin-containing solution, and
At least one solvent selected from the above-mentioned lignin-resin-containing solution and hydrocarbons having a volume of 1 to 50 times or less of the lignin-resin-containing solution and a dipole moment of 0.25 d or less. Step of mixing with (a') (IB)
A method for producing a lignin-containing resin composition, which comprises. A lignin-containing resin composition obtained by the method according to claim 7 , or a molded product using the resin composition.