JP4670011B2 - Lignin-containing resin, method for producing the same, and method for separating lignin - Google Patents

Description

  The present invention relates to a method for producing a lignin-containing resin from a solvent containing lignin, such as an organosolved pulp waste liquor, a lignin-containing resin obtained thereby, and a method for separating lignin.

  Development of technology that uses low-quality wood and wood-based waste as organic resources (biomass) is important in terms of improving the global environment and effectively using organic resources. Lignin is known as a kind of biomass. Lignin is a natural polymer substance present in trees, and its use as a fuel is known. For the purpose of using lignin as a structural material, the production of phenol resins and epoxy resins using lignin as a monomer has been studied for a long time (see, for example, Non-Patent Document 1). Thus, effective utilization of lignin has been studied.

  On the other hand, polymer blend technology has attracted attention. This technique is capable of creating new polymer materials from known polymers, is low cost, and is a commercially important technique. A part of polymer blends based on lignin has also been studied (for example, see Patent Document 1). In this document, the lignin blend increases the mechanical strength, but no special intermolecular interaction occurs between the lignin and the polyolefin, so that the lignin is about 0.1 to about 100 microns. Only phase-separated polymers with dimensions are obtained, the thermal properties are maintained and the heat processability is not improved. Moreover, the report which mixed lignin and polyvinyl alcohol is also reported (for example, refer nonpatent literature 2). In this report, the obtained blend polymer is essentially incompatible, and two glass transition points (Tg) are confirmed, which is inconvenient in terms of thermal processability. As in these examples, a lignin-containing polymer that exhibits essentially good compatibility with lignin and a method for producing the same have not been known.

Also, since lignin accounts for about 30% of wood, lignin has been removed to pulp wood. However, since the effective use of lignin has been studied as described above, attempts have been made to separate lignin from pulping waste liquid. Pulp obtained by chemically removing lignin in wood chips is called chemical pulp (CP) and is roughly classified into sulfite pulp (SP) and kraft pulp (KP) depending on the chemicals used. Sulphite pulp (SP) is produced by pulping wood chips using a liquid (cooking liquid) consisting of sulfite and sulfite. There are various salts such as Ca, Na, Mg, NH _3, and there are various methods such as acidic sulfite cooking and bisulfite cooking depending on the combination of pH. Kraft pulp (KP) is produced by cooking wood chips for about 2 to 5 hours at a temperature of about 160 to 170 ° C. using a mixed solution (cooking solution) of sodium hydroxide and sodium sulfide. In the cooking process where wood chips are cooked with cooking liquor, lignin in the wood is treated with a high-temperature alkaline solution (NaOH + Na ₂ S) to lower the molecular weight, and phenolic OH groups and carboxyl groups are increased and eluted. In addition, in order to improve the cooking yield in the KP method, the MOXY method that improves the yield by stabilizing the aldehyde group of cellulose by polysulfide cooking and suppressing the decay reaction (peeling reaction) from the end group of cellulose molecular chain, A quinone addition method in which a trace amount of anthraquinone, anthrahydroquinone, or the like is added to the cooking solution may be performed.

When recovering lignin from KP waste liquid obtained by kraft cooking, a method for separating lignin-containing precipitates by acidification of the waste liquid (for example, pH 3) is known. (For example, refer nonpatent literature 3). In addition, since KP waste liquid exhibits ionic interaction, there is a method in which lignin is aggregated by adding a flocculant such as FeCl ₃ and Al ₂ (SO ₄ ) ₃ or a polymer electrolyte, and separated as a precipitate. Are known. Moreover, since the lignin sulfonic acid obtained from a sulfite pulping waste liquid (SP waste liquid) also shows an ionic interaction, a lignin sulfonic acid can be isolate | separated by addition of said flocculant or a polymer electrolyte.

However, the SP method and the KP method have problems of relatively high equipment costs and contamination. Therefore, recently, an organosolv pulping method in which wood is treated with an organic solvent such as alcohol or acetic acid to separate lignin-containing waste liquid to produce pulp (for example, non-patent literature). 4, see Patent Document 2 and Patent Document 3). In the organosolv pulping method, as shown in FIG. 1, after cooking, it is separated into pulp and waste liquid by a separator, the organic solvent in the waste liquid is removed by distillation, and a large amount of water is added to the solid content of the generated waste liquid. Is added to separate a water-soluble part and a water-insoluble part, and saccharides are recovered from the water-soluble part and lignin is recovered from the water-insoluble part (precipitation).
Japanese National Patent Publication No. 10-501295 Japanese Patent Laid-Open No. 11-12971 JP 2001-89986 A Junzo Nakano, “Science of Lignin: Basics and Applications”, 1979, 387 pages, Uni Publishing Biomacromolecules, Volume 4, 2003, No. 3, 561-567 Junzo Nakano, "Science of Lignin-Fundamentals and Applications", 1979, page 379, Uni Publishing Papa Gikyo Magazine 45, 1991, September, 62-68

  Thus, a lignin-containing resin having essentially good compatibility with lignin and having a single glass transition point and a method for producing the same have not been known. Moreover, in organosolv pulping, in order to obtain lignin, it was necessary to process with a lot of water for a long time, and it was difficult to isolate | separate lignin easily in a short time.

  Accordingly, an object of the present invention is to provide a composite resin of lignin and a vinyl polymer and a lignin-containing resin that is compatible with lignin, and to easily separate lignin from an organosolv pulp liquid or waste liquid in a short time. To do.

  As a result of intensive studies in view of the above-mentioned problems of the prior art, the present inventor added an amide bond-containing vinyl polymer to a solvent in which lignin was dissolved, so that the hydroxyl group of lignin and the amide carbonyl of the vinyl polymer were reduced. It is possible to produce a hydrogen-bonded lignin-containing resin, and lignin from a liquid obtained by adding a lignin-soluble solvent to a lignin-containing resin obtained by adding an amide bond-containing vinyl polymer to an oxygen-containing heterocyclic compound in which lignin is dissolved. And the present invention was completed.

That is, this invention relates to the following lignin containing resin, its manufacturing method, and a lignin separation method.
Item 1. A method for producing a lignin-containing resin, comprising a step of adding an amide bond-containing vinyl polymer to a solvent in which lignin is dissolved to form a lignin-containing resin, and a step of recovering the formed lignin-containing resin.
Item 2. An amide bond-containing polymer is
Homopolymer of an amide bond-containing monomer selected from the group consisting of N-vinyl-2-pyrrolidone, N-vinyl-2-methylpyrrolidone, acryloylmorpholine, acryloyl-2-methylmorpholine and vinylacetamide, and said monomer and vinyl monomer Item 2. The production method according to Item 1, wherein the polymer is at least one polymer selected from the group consisting of copolymers.
Item 3. Item 2. The production method according to Item 1, which is a solvent oxygen-containing heterocyclic compound.
Item 4. Item 4. The production method according to Item 3, wherein the oxygen-containing heterocyclic compound is at least one selected from the group consisting of oxirane, oxetane, tetrahydrofuran, and tetrahydropyran.
Item 5. Item 2. The production method according to Item 1, wherein the solvent is at least one selected from the group consisting of an aprotic polar solvent, ethanol, isopropanol, butanol, ethyl acetate, pyridine, and chloroform.
Item 6. Item 2. The production method according to Item 1, wherein the solvent in which lignin is dissolved is an organosolv pulping solution or an organosolv pulping waste solution.
Item 7. The solvent in which lignin is dissolved consists of oxygen-free heterocyclic compounds, aprotic polar solvents, ethanol, isopropanol, butanol, ethyl acetate, pyridine, and chloroform as non-distilled components obtained by distilling organosolv pulp waste liquor. Item 2. The production method according to Item 1, which is obtained by adding at least one solvent selected from the group.
Item 8. Item 8. The production method according to Item 6 or 7, wherein the organosolv pulping solution or waste solution is obtained by treating a pulp raw material with an aqueous solvent containing at least one selected from the group consisting of acetic acid and alcohol.
Item 9. The lignin containing resin obtained by the manufacturing method in any one of claim | item 1 -8.
Item 10. Addition of an amide bond-containing vinyl polymer having a three-dimensional cross-linking structure to an oxygen-containing heterocyclic compound in which lignin is dissolved to precipitate the lignin-containing resin, recovering the precipitated lignin-containing resin, and recovered lignin-containing A lignin separation method comprising a step of adding a lignin-soluble solvent to a resin, separating a solid, and recovering a liquid.
Item 11. Item 11. The method for separating lignin according to Item 10, wherein the oxygenated heterocyclic compound in which lignin is dissolved is obtained by adding an oxygenated heterocyclic compound to an organosolv pulping solution or an organosolv pulping waste solution.
Item 12. Item 11. The lignin separation method according to Item 10, wherein the oxygenated heterocyclic compound in which lignin is dissolved is obtained by adding an oxygenated heterocyclic compound to a non-distilled component obtained by distilling an organosolv pulping waste liquid. .
Item 13. Item 13. The method according to Item 11 or 12, wherein the organosolv pulping solution or waste solution is obtained by treating a pulp raw material with an aqueous solvent containing at least one selected from the group consisting of acetic acid and alcohol.

  The outline of the present invention is as follows.

  As shown in FIG. 2, the lignin-containing resin production method and lignin separation method of the present invention typically produce a waste liquid by separating crude pulp and waste liquid produced by organosolv pulping by filtration or the like. The solid content (non-distilled component) obtained by distilling is at least selected from the group consisting of a liquid oxygen-containing heterocyclic compound, an aprotic polar solvent, ethanol, isopropanol, butanol, ethyl acetate, pyridine and chloroform. Adding at least one solvent selected from the group consisting of one and an amide bond-containing vinyl polymer. However, the addition target of the amide bond-containing vinyl polymer is not limited to the above non-distilled component dissolving solvent, but may be any solvent in which lignin is dissolved. For example, a mixture of crude pulp and waste liquid obtained by organosolv pulping Alternatively, it may be a waste liquid obtained by removing crude pulp from the mixture. In addition, since the component distilled off from the waste liquid contains an organic solvent for pulping, the organic solvent obtained by purifying the distilled component itself or the distilled component is Can be reused for.

  In the present invention, two types of lignin-containing resins are obtained depending on the type of solvent. The first is a complex (complex) obtained by strong hydrogen bonding between the hydroxyl group of lignin and the amide carbonyl of the amide bond-containing vinyl polymer. The second is a compatible polymer in which the hydroxyl group of lignin and the amide carbonyl of the amide bond-containing vinyl polymer are weakly hydrogen-bonded and compatible with each other.

  For the production of the composite, a poor solvent (for example, an oxygen-containing heterocyclic compound) of an amide bond-containing vinyl polymer is used. For the production of the compatible polymer, a good solvent (for example, aprotic polar solvent, ethanol, isopropanol, butanol, ethyl acetate, pyridine, chloroform) of an amide bond-containing vinyl polymer is used. When the poor solvent and amide bond-containing vinyl polymer are added to lignin, the complex is precipitated, and the lignin-containing resin of the present invention can be produced by collecting the precipitate. In addition, when the above-mentioned good solvent and amide bond-containing vinyl polymer are added to lignin, the above-mentioned compatible polymer is formed, and when the liquid content is removed by distillation or the like, the film-like compatible polymer can be recovered and the lignin-containing material of the present invention Resin can be manufactured.

  Further, by adding a lignin-soluble solvent such as ethanol to the complex obtained by adding the amide bond-containing vinyl polymer that is three-dimensionally crosslinked with the poor solvent to lignin, the lignin is eluted and the lignin-containing solvent Resin precipitation occurs. By separating the former and removing the solvent in the former by a known method such as distillation, the lignin dissolved in the solvent can be isolated. The lignin-containing resin used for separating lignin is preferably a lignin-containing resin obtained by using a crosslinked amide bond-containing vinyl polymer among amide bond-containing vinyl polymers. This is because the resin component of the lignin-containing resin obtained from the cross-linked amide bond-containing vinyl polymer is difficult to dissolve in the lignin-soluble solvent, so that the lignin and the resin component can be easily separated.

  Next, the present invention will be described in more detail.

  In the present invention, an amide bond-containing vinyl polymer is added to a solvent in which lignin is dissolved to form a lignin-containing resin. This step includes the case where the solvent and the amide bond-containing vinyl polymer are added to lignin. Examples of the solvent include at least one solvent selected from the group consisting of oxygen-containing heterocyclic compounds, aprotic polar solvents, ethanol, isopropanol, butanol, ethyl acetate, pyridine and chloroform. Moreover, an organosolv pulping liquid or an organosolv pulping waste liquid can be used as a solvent in which lignin is dissolved. Furthermore, as a solution in which lignin is dissolved, a lignin-dissolved solution obtained by adding a solvent to a non-distilled component (solid content) obtained by distilling an organosolv pulping waste liquid can also be used.

  If an oxygen-containing heterocyclic compound is added to the organosolv pulping solution as necessary and an amide bond-containing resin is added, the lignin-containing resin is precipitated. In this case, the lignin-containing resin can be separated from the crude pulp in the pulping solution by adjusting conditions such as centrifugation. However, the lignin-containing resin can be more easily separated by devising the resulting lignin-containing resin not to be mixed with the crude pulp. For example, an amide bond-containing resin is put into a bag having a solid-liquid separation ability such as a tea bag, and the bag is put into an organosolv pulping solution, whereby the lignin-containing resin is precipitated in the bag, A lignin-containing resin can be easily obtained by removing from the liquid.

  In the case of producing a complex (complex) of lignin and a vinyl polymer, a poor solvent for the vinyl polymer, for example, an oxygen-containing heterocyclic compound is preferable as the solvent. In the case of producing a compatible polymer of lignin and a vinyl polymer, an aprotic polar solvent, ethanol, isopropanol, butanol, ethyl acetate, pyridine, chloroform or the like is preferable as a solvent.

  In the present invention, the oxygen-containing heterocyclic compound is preferably a poor solvent for the amide bond-containing vinyl polymer. This is because the poor solvent has little interaction between the vinyl polymer and the solvent, so that the interaction between the vinyl polymer and lignin increases. As the oxygen-containing heterocyclic compound, oxiranes, oxetanes, tetrahydrofurans, tetrahydropyrans, furans, pyrans and the like correspond to the above poor solvents and can be preferably used. The oxygen-containing heterocyclic compound can be used alone or in combination of two or more. Preference is given to ethylene oxide, propylene oxide, oxetane, tetrahydrofuran, tetrahydropyran, furan, pyran and those having an alkyl group having 1 or 2 carbon atoms added thereto.

  In the present invention, an aprotic polar solvent, ethanol, isopropanol, butanol, ethyl acetate, pyridine, chloroform or the like is used as a good solvent. Examples of the aprotic polar solvent include N, N-dimethylformamide, dimethyl sulfoxide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone and the like. Preferred as good solvents are N, N-dimethylformamide, dimethyl sulfoxide, and N, N-dimethylacetamide.

  Organosolv pulping is a known pulping method. Typical organosolv pulping involves converting pulp raw materials, such as wood chip produce waste, into organosolv pulping agents, ie acetic acid, alcohols (eg methanol, ethanol, butanol, isopropanol, etc.), polyhydric alcohols (eg ethylene glycol). Or the like, or an aqueous solvent containing about 80% by weight of an organic solvent such as acetone or the like (treatment) at about 100 to 200 ° C. Moreover, you may add acids, such as alkalis, such as sodium hydroxide, and a mineral acid, to a process liquid as needed. As the organic solvent used for the organosolv pulping agent, acetic acid and alcohol are preferred, acetic acid and ethanol are more preferred, and acetic acid is even more preferred.

  Thus, in this specification, the mixture of the crude pulp and waste liquid which arise by organosolv pulping is called organosolv pulping liquid. Moreover, in this specification, the waste liquid obtained by isolate | separating crude pulp from organosolv pulping liquid by methods, such as filtration and centrifugation, is called organosolv pulping waste liquid. In the present invention, as a solvent dissolving lignin, organosolv pulping liquid itself, organosolv pulping waste liquid itself, or organosolv pulping liquid or waste liquid containing oxygen-containing heterocyclic compound, aprotic polar solvent, ethanol, isopropanol, butanol , Ethyl acetate, pyridine, and chloroform can be used to which at least one solvent selected from the group consisting of is added.

  When the organosolv pulping waste liquid is distilled, a non-distilled component (solid content) is generated. Non-distilled components produced by distillation contain lignin. In distillation, normal distillation conditions (temperature, time, pressure, etc.) can be adopted, and it may be appropriately set according to the components (organic solvent, water, alkali, acid, etc.) contained in the waste liquid, the concentration thereof, and the like. In addition, the component distilled off in this process can be collect | recovered and can be reused as a pulping agent (pulping reagent).

  Next, by the above process, the above solvent and amide bond-containing vinyl polymer are added to the non-distilled component containing lignin obtained from the organosolv pulping waste liquid to form a lignin-containing resin. In this step, at least one member selected from the group consisting of the above-mentioned solvent, preferably an oxygen-containing heterocyclic compound, an aprotic polar solvent, ethanol, isopropanol, butanol, ethyl acetate, pyridine and chloroform is used as the non-distilled component. A solvent and the above amide bond-containing vinyl polymer are added. There are various methods of addition, a method of adding a solvent to the non-distilled component and then adding a solid or liquid (solution, suspension, etc.) amide bond-containing vinyl polymer, a solid or liquid (solution) to the non-distilled component , Suspension, etc.), a method of adding an amide bond-containing vinyl polymer and then adding a solvent, a mixture of a solvent and a solid or liquid (solution, suspension, etc.) amide bond-containing vinyl polymer as a non-distilled component Examples thereof include, but are not limited to, a technique of adding a solvent and a solid or liquid (solution, suspension, etc.) amide bond-containing vinyl polymer separately and simultaneously to the non-distilled component.

In the present invention, the amide bond-containing vinyl polymer includes a vinyl polymer having an amide bond in the side chain, and can be used alone or in combination of two or more. However, simple amide groups, i.e. the vinyl polymer having a -CO-NH ₂ are not included. Examples of the amide bond-containing vinyl polymer include homopolymers of amide bond-containing monomers such as N-vinyl-2-pyrrolidone, N-vinyl-2-methylpyrrolidone, acryloylmorpholine, acryloyl-2-methylmorpholine, and vinylacetamide; Copolymers of monomers and vinyl monomers can be used. The amide bond-containing monomers that are monomers of the amide bond-containing vinyl polymer can be used alone or in combination of two or more. The amide bond-containing vinyl polymer used in the lignin separation method of the present invention described later is preferably a three-dimensionally cross-linked amide bond-containing vinyl polymer. This is because the resin component of the lignin-containing resin obtained from the cross-linked amide bond-containing vinyl polymer is difficult to dissolve in the lignin-soluble solvent, so that the lignin and the resin component can be easily separated. Such a crosslinked structure can be obtained, for example, by irradiating an amide bond-containing vinyl polymer with γ rays.

  The above vinyl monomers include ethylene, propylene, styrene, vinyl acetate, vinyl alcohol, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, acrylic Acid butyl, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylonitrile and the like can be used, but are not limited thereto. A vinyl monomer can be used individually by 1 type or in combination of 2 or more types.

  The form of the amide bond-containing vinyl polymer added to lignin is not limited, and may be, for example, a solid such as a powder or a liquid dissolved in a solvent (for example, tetrahydrofuran). The number average molecular weight of the amide bond-containing vinyl polymer is usually 1,000 to 500,000, preferably 5,000 to 200,000. The addition amount of the amide bond-containing vinyl polymer is usually 2 to 98% by weight, preferably 5 to 50% by weight, based on lignin.

  The lignin-containing resin formed by adding the amide bond-containing vinyl polymer can be recovered by a known method. In the case where the formed lignin-containing resin is a composite, precipitation of the composite occurs in a solvent, which can be separated by a known solid-liquid separation method such as filtration, distillation of the solvent, and centrifugation. When the formed lignin-containing resin is a compatible polymer, for example, a film-like polymer can be separated by removing the solvent by a method such as distillation. The obtained lignin-containing resin can be used for conventionally known applications such as agricultural films, transplant seedling pots, sandbag bags, agricultural and fishery materials such as fishing gear, and civil engineering and construction materials such as heat insulating materials, water retaining sheets, and formwork.

  In this invention, the addition amount of said solvent is 1-200 weight part normally with respect to 1 weight part of lignin, Preferably it is 5-100 weight part. Moreover, the addition amount of an amide bond containing vinyl polymer is 0.5-10 weight part normally with respect to 1 weight part of lignin in a non-distilled component, Preferably it is 1-5 weight part.

  The amount of the polymer derived from the amide bond-containing vinyl polymer in the lignin-containing resin is usually 2 to 98% by weight, preferably 5 to 50% by weight. The ratio of lignin in the lignin-containing resin is usually 2 to 98% by weight, preferably 50 to 95% by weight. The number average molecular weight of lignin is usually 1,000 to 20,000, preferably 2,000 to 10,000.

  The lignin separation method of the present invention, that is, the step of adding an amide bond-containing vinyl polymer having a three-dimensional cross-linking structure to an oxygen-containing heterocyclic compound in which lignin is dissolved to precipitate the lignin-containing resin, and recovering the precipitated lignin-containing resin In the lignin separation method, including a step of adding a lignin-soluble solvent to the recovered lignin-containing resin, and separating a solid to recover a liquid, the lignin is separated from the recovered lignin-containing resin. Adds a lignin-soluble solvent to the recovered lignin-containing resin, separates the resulting solid content, and adds the lignin-soluble solvent to the recovered solid to separate lignin. While lignin in the lignin-containing resin is eluted by the addition of a lignin-soluble solvent, the resin component does not dissolve but becomes a solid content. Next, the solvent can be removed from the liquid obtained by adding the lignin-soluble solvent (for example, distillation under reduced pressure, etc.) to separate the lignin as a solid. The lignin-containing resin used in the lignin separation method of the present invention is a lignin-containing resin produced by adding a three-dimensionally crosslinked amide bond-containing vinyl polymer. This is because the resin component of the lignin-containing resin obtained from the cross-linked amide bond-containing vinyl polymer is difficult to dissolve in the lignin-soluble solvent, so that the lignin and the resin component can be easily separated.

  The lignin-soluble solvent has the property of dissolving lignin and not dissolving the resin component in the lignin-containing resin, for example, ethanol, methanol, acetone, chloroform, dichloromethane, dimethylformamide, dimethylacetamide, dimethylsulfoxide, etc. can give. The addition amount of the lignin-soluble solvent is usually 1 to 10 parts by weight, preferably 2 to 5 parts by weight with respect to 1 part by weight of the lignin-containing resin.

  According to the present invention, since the compatibility between lignin and vinyl resin is high and the glass transition point is one, a lignin-containing resin excellent in heat workability can be obtained. Moreover, according to the lignin separation method of the present invention, lignin can be separated from the organosolv pulping waste liquor without using a large amount of water, so that energy such as water distillation becomes unnecessary.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.

Example 1
Put the eucalyptus chips in the pulping tank, and put in this acetic acid aqueous solution containing a small amount of mineral acid (90% acetic acid aqueous solution containing 0.1% hydrochloric acid, the liquid ratio to the chips is 10-12, 3-4 hours The mixture was refluxed (atmospheric pressure acetic acid treatment) and then filtered by suction to separate into crude pulp and pulp waste liquid, and the pulp waste liquid was distilled under reduced pressure to be concentrated and solidified 99 parts by weight of tetrahydrofuran with respect to 1 part by weight of the solidified product. When 50 parts by weight of the solution dissolved in addition and 50 parts by weight of a solution obtained by dissolving 1 part by weight of polyvinylpyrrolidone K-90 (number average molecular weight 360,000) manufactured by Nacalai Tesque in 99 parts by weight of tetrahydrofuran are mixed. A precipitate formed instantaneously, which was collected by centrifugation, and the resulting precipitate was lignin-containing polyvinylpyrrolidone. It was 95% with respect to the lignin contained in the distilled-obtained concentrated individuals.

Example 2
Pulp waste liquor was obtained in the same manner as in Example 1. Tetrahydrofuran was added to the mixture of the crude pulp and the pulp waste liquid 10 times as much as the acetic acid aqueous solution. 200 mL of this was placed in a flask, 10 g of polyvinyl polypyrrolidone manufactured by Nacalai Tesque Co., Ltd. was placed in a tea bag-like bag and mixed, and then allowed to stand for 10 minutes to produce a precipitate (lignin-containing polyvinyl polypyrrolidone). Next, this precipitate was collected by filtration, and 50 parts by weight of ethanol was added to 1 part by weight of the precipitate. The lignin dissolved by the addition of ethanol was recovered as a solid by distilling off ethanol under reduced pressure, and the lignin yield was calculated to be 75% of the lignin contained in the mixture of the crude pulp and the pulp waste liquid. Polyvinyl polypyrrolidone is a polymer having a three-dimensional network structure obtained by cross-linking polyvinyl pyrrolidone, and a powder having an average particle size of 200 μm or less was used.

Example 3
20, 40, 60, 80 parts by weight of a solution prepared by dissolving 1 part by weight of an organosolv lignin acetate manufactured by Aldrich in 99 parts by weight of N, N-dimethylformamide, and polyvinylpyrrolidone (PVP) manufactured by Nacalai Tesque 80, 60, 40 and 20 parts by weight of a solution prepared by dissolving 1 part by weight of 25 (molecular weight 360,000) in 99 parts by weight of N, N-dimethylformamide were mixed to make a total of 100 parts by weight. N, N-dimethylformamide was distilled off to obtain a brown film-like resin composition. The glass transition point (Tg) of the resin composition was measured by DSC manufactured by Perkin Elmer. The results are shown in FIG. Tg alone was a value between 112 ° C. which is Tg of organosolv lignin acetate and 162 ° C. which is Tg of PVP25.

Next, the intermolecular interaction of both components was evaluated using an FT-IR apparatus manufactured by Perkin Elmer. The results are shown in FIGS. From band 3455cm ^-1 derived from the stretching vibration of the hydroxyl groups of organosolv lignin acetate, band ascribed to the stretching vibration of the carbonyl group of PVP was shifted from 1680 cm ^-1 to the respective lower wavenumbers. This confirmed that a hydrogen bond was working between the hydroxyl group in lignin and the carbonyl carbon of the amide group of the amide bond-containing vinyl polymer (PVP).

Example 4
In Example 3, when organosolv lignin acetate and PVP 25 were mixed using tetrahydrofuran instead of N, N-dimethylformamide, a brown precipitate was instantly deposited. The precipitate was collected by filtration. The Tg value is shown in FIG. Tg was 168-182 ° C. alone, and sometimes showed a higher value than 181 ° C., which is the Tg of PVP25. The results of evaluating the intermolecular interaction of both components by FT-IR are shown in FIGS. From band 3455cm ^-1 derived from the stretching vibration of the hydroxyl groups of organosolv lignin acetate, band ascribed to the stretching vibration of the carbonyl group of PVP was shifted from 1680 cm ^-1 to the respective lower wavenumbers. This confirmed that a hydrogen bond was working between the hydroxyl group in lignin and the carbonyl carbon of the amide group of the vinyl polymer having an amide bond. Furthermore, the degree of shift was greater than in Example 3, and it was revealed that a complex-like complex was formed between both components by forming stronger hydrogen bonds. This strong hydrogen bond is considered to indicate that Tg is higher than 162 ° C., which is the Tg of PVP25.

  The present invention can be used in the field of organosolv pulping, the field of lignin production, the field of lignin-containing resins, and the like.

It is a flowchart showing the conventional method for lignin separation in an organosolv pulping method. It is process drawing of the typical example of the lignin containing resin manufacturing method of this invention. The Tg of lignin containing resin manufactured in Example 3 and 4 is shown. The FT-IR of the lignin containing resin manufactured in Example 3 and 4 is shown. The FT-IR of the lignin containing resin manufactured in Example 3 and 4 is shown.

Claims (11)

In a method for producing a lignin-containing resin, comprising a step of adding an amide bond-containing vinyl polymer to a solvent in which lignin is dissolved to form a lignin-containing resin, and a step of recovering the formed lignin-containing resin .
A method for producing a lignin-containing resin in which the solvent in which lignin is dissolved is any of the following:
(A) Organosolv pulping solution,
(B) Organosolv pulping waste liquid,
(C) adding at least one solvent selected from the group consisting of oxygen-containing heterocyclic compounds, aprotic polar solvents, ethanol, isopropanol, butanol, ethyl acetate, pyridine and chloroform to the organosolv pulping solution or waste solution. Or obtained
(D) The non-distilled component obtained by distilling the organosolv pulping waste liquid is selected from the group consisting of oxygen-containing heterocyclic compounds, aprotic polar solvents, ethanol, isopropanol, butanol, ethyl acetate, pyridine and chloroform. at least one solvent that obtained by adding that. An amide bond-containing polymer is
Homopolymer of an amide bond-containing monomer selected from the group consisting of N-vinyl-2-pyrrolidone, N-vinyl-2-methylpyrrolidone, acryloylmorpholine, acryloyl-2-methylmorpholine and vinylacetamide, and said monomer and vinyl monomer The production method according to claim 1, wherein the polymer is at least one polymer selected from the group consisting of copolymers thereof. The production method according to claim 1, wherein the solvent is an oxygen-containing heterocyclic compound. The production method according to claim 3, wherein the oxygen-containing heterocyclic compound is at least one selected from the group consisting of oxirane, oxetane, tetrahydrofuran, and tetrahydropyran. The production method according to claim 1, wherein the solvent is at least one selected from the group consisting of an aprotic polar solvent, ethanol, isopropanol, butanol, ethyl acetate, pyridine, and chloroform. The method according to claim 1, wherein the solvent in which lignin is dissolved is an organosolv pulping solution or an organosolv pulping waste solution. The solvent in which lignin is dissolved consists of oxygen-free heterocyclic compounds, aprotic polar solvents, ethanol, isopropanol, butanol, ethyl acetate, pyridine, and chloroform as non-distilled components obtained by distilling organosolv pulp waste liquor. The production method according to claim 1, which is obtained by adding at least one solvent selected from the group. Organosolv pulping liquid or liquid waste, according to claim 1 in an aqueous solvent containing at least one member selected from the group consisting of acetic acid and alcohol is obtained by processing the pulp material Production method. A lignin-containing resin obtained by the production method according to claim 1. Addition of an amide bond-containing vinyl polymer having a three-dimensional cross-linking structure to an oxygen-containing heterocyclic compound in which lignin is dissolved to precipitate the lignin-containing resin, recovering the precipitated lignin-containing resin, and recovered lignin-containing lignin-soluble solvent is added to the resin, the lignin separation method comprising the step of recovering the liquid by separating the solids,
The lignin separation method wherein the solvent in which lignin is dissolved is any of the following:
(A) a solution obtained by adding an oxygen-containing heterocyclic compound to an organosolv pulping solution,
(B) A solution obtained by adding an oxygen-containing heterocyclic compound to an organosolv pulping waste liquid, or
(C) A product obtained by adding an oxygen-containing heterocyclic compound to a non-distilled component obtained by distilling an organosolv pulping waste liquid . The method according to claim 10 , wherein the organosolv pulping liquid or waste liquid is obtained by treating a pulp raw material with an aqueous solvent containing at least one selected from the group consisting of acetic acid and alcohol.

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