JP2012201645A - Method for producing lignin derivative, method for producing lignin secondary derivative, lignin derivative and lignin secondary derivative - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lignin derivative and a lignin secondary derivative, having excellent meltability and solubility, and high reactivity, and providing a cured product having excellent mechanical characteristics, and to provide a method for efficiently producing the lignin derivative and a method for efficiently producing the lignin secondary derivative.SOLUTION: The method for producing the lignin derivative is a method for producing the lignin derivative by degrading a biomass, and includes a degradation step of carrying out the degradation treatment of the biomass under a high-temperature and high-pressure condition in the presence of a mixed solvent of water and a nonprotonic polar solvent, and a distillation step of distilling off the nonprotonic polar solvent from the treated product obtained in the degradation step, and obtaining the lignin derivative as an insoluble component in the residue. The method for producing the lignin secondary derivative includes each of the steps, and a reactive group-introducing step of mixing a compound containing a reactive group such as an epoxy group with the lignin derivative.

Description

  The present invention relates to a method for producing a lignin derivative, a method for producing a lignin secondary derivative, a lignin derivative, and a lignin secondary derivative.

  Many wood-based waste materials (biomass) such as bark, thinned wood, and building waste have been disposed of so far. However, protection of the global environment is becoming an important issue, and from this point of view, the reuse and recycling of wood-based waste materials are being considered.

  Common woody main components are cellulose, hemicellulose and lignin. Among these, lignin contained at a ratio of about 30% has a structure containing abundant aromatic rings, phenolic hydroxyl groups, and alcoholic hydroxyl groups, and therefore, utilization as a resin raw material has been studied (for example, (See Patent Document 1).

  Thus, in order to utilize lignin as a resin raw material, it is necessary to isolate lignin from a wooden waste material.

  In Patent Document 1, a liquid phenol derivative is infiltrated into wood flour, lignin in wood flour is solvated with a phenol derivative, and then concentrated acid is added to dissolve the cellulose component, thereby dissolving lignin as a solvent. A method is disclosed in which a hydrated phenol derivative and a concentrated acid in which a cellulose component is dissolved are separated into two phases, and a lignin phenol derivative is extracted from the phenol derivative phase.

  Further, in Patent Document 1, a solvent in which a phenol derivative is dissolved in wood flour is infiltrated, and then the solvent is distilled off. Thereafter, concentrated acid is added to the remaining wood flour, thereby being solvated by the phenol derivative. A method for obtaining lignin is disclosed.

  However, the lignin derivative produced by the method as described above has problems of low meltability and solubility, brittleness even when crosslinked and cured, and low mechanical properties.

JP 2001-261839 A

  An object of the present invention is to provide a lignin derivative and a lignin secondary derivative that have excellent meltability and solubility, high reactivity, and excellent mechanical properties when cured, and lignin derivatives that efficiently produce them. It is in providing the manufacturing method and the manufacturing method of a lignin secondary derivative.

Such an object is achieved by the present inventions (1) to (10) below.
(1) A method for producing a lignin derivative obtained by decomposing biomass,
A decomposition step of placing biomass in the presence of a mixed solvent containing water and an aprotic polar solvent and decomposing them under high temperature and high pressure;
And a distillation step of distilling off the aprotic polar solvent from the treated product obtained in the decomposition step to obtain a lignin derivative as an insoluble matter in the residue.

  (2) The said decomposition process is a manufacturing method of the lignin derivative as described in said (1) which decomposes | disassembles by processing temperature 150-350 degreeC, processing pressure 1-8 Mpa, and processing time 480 minutes or less.

  (3) The said decomposition process is a manufacturing method of the lignin derivative as described in said (1) or (2) performed under subcritical conditions of water or an aprotic polar solvent.

  (4) The method for producing a lignin derivative according to any one of (1) to (3), wherein the aprotic polar solvent has a boiling point lower than that of water.

  (5) The method for producing a lignin derivative according to (4), wherein the difference in boiling point between water and the aprotic polar solvent is 5 to 60 ° C.

  (6) The method for producing a lignin derivative according to any one of (1) to (5), wherein the aprotic polar solvent is at least one of ketones and cyclic ethers.

(7) A method for producing a lignin secondary derivative obtained by introducing a reactive group into a lignin derivative obtained by decomposing biomass,
A decomposition step of placing biomass in the presence of a mixed solvent containing water and an aprotic polar solvent and decomposing them under high temperature and high pressure;
A distillation step of distilling off the aprotic polar solvent from the treated product obtained by the decomposition step;
A method for producing a lignin secondary derivative, comprising: a reactive group introducing step of mixing the treated product obtained in the distillation step and the compound containing the reactive group.

  (8) The method for producing a lignin secondary derivative according to (7), wherein the reactive group is an epoxy group.

  (9) A lignin derivative produced by the method for producing a lignin derivative according to any one of (1) to (6) above.

  (10) A lignin secondary derivative produced by the method for producing a lignin secondary derivative according to (7) or (8) above.

  According to the present invention, a lignin derivative and a lignin secondary derivative having excellent meltability and solubility and excellent reactivity can be obtained. Moreover, it is suitable for the production of a lignin resin composition that can produce a resin product having excellent impregnation into a substrate and excellent mechanical properties, and can easily produce a desired reactive group useful as a resin raw material. The lignin derivative and lignin secondary derivative that can be introduced can be produced in high yield. As a result, it becomes possible to provide a resin composition and a resin substrate having excellent characteristics at low cost.

  Hereinafter, the manufacturing method of the lignin derivative of the present invention, the manufacturing method of the lignin secondary derivative, the lignin derivative and the lignin secondary derivative will be described in detail based on preferred embodiments.

  The lignin derivative in the present invention is obtained by decomposing biomass and can be a resin raw material.

  Moreover, the lignin secondary derivative in the present invention is obtained by introducing a reactive group into the above-described lignin derivative.

<Lignin derivative and lignin secondary derivative>
First, prior to the description of the method for producing the lignin derivative of the present invention and the method for producing the lignin secondary derivative, the lignin derivative of the present invention and the lignin secondary derivative of the present invention produced by these production methods will be described.

  These lignin derivatives and lignin secondary derivatives are obtained by decomposing biomass as described above.

  The biomass in the present invention is a plant containing lignin or a processed product of the plant. Examples of the plant include broad-leaved trees such as beech, birch and oak, conifers such as cedar, pine, and oak, grasses such as bamboo and rice straw, and coconut shells.

  A lignin derivative is a compound having a phenol derivative as a unit structure. Since this unit structure has a chemically and biologically stable carbon-carbon bond or carbon-oxygen-carbon bond, it is less susceptible to chemical degradation and biological degradation. For this reason, a lignin derivative is useful as a resin raw material.

  Specific examples of the lignin derivative include a guaiacylpropane structure represented by the following formula (1), a syringylpropane structure represented by the following formula (2), and a 4-hydroxyphenylpropane structure represented by the following formula (3). Can be mentioned.

  Moreover, the lignin derivative in the present invention is preferably one in which at least one of the ortho-position and para-position of the aromatic ring is unsubstituted with respect to the hydroxyl group. Such a lignin derivative is excellent in reactivity because it contains a large number of reaction sites where a curing agent acts due to electrophilic substitution reaction on the aromatic ring and steric hindrance can be reduced in the reaction with a hydroxyl group.

  In addition, the lignin derivative in the present invention preferably has a polystyrene-equivalent number average molecular weight of 200 to 2000 as measured by gel permeation chromatography, and more preferably 300 to 1800. Such a lignin derivative having a number average molecular weight has a higher balance between reactivity (curability) and meltability or solubility. For this reason, the utilization as a resin raw material can be improved more.

  In addition, when a number average molecular weight is less than the said lower limit, there exists a possibility that the reactivity of a lignin derivative may fall. On the other hand, when the number average molecular weight exceeds the upper limit, the softening point of the lignin derivative is too high, and the meltability or solubility may be lowered.

In addition, the lignin derivative in the present invention, when subjected to ¹ H-NMR analysis, in the obtained chemical shift spectrum, the integrated value of the peak attributed to the aromatic proton is the integrated value of the peak attributed to the aliphatic proton. Is preferably about 15 to 50%, more preferably about 15 to 45%, still more preferably about 20 to 40%, and particularly preferably about 20 to 35%. Thereby, the reactivity which contributes to the mechanical characteristic of the cured resin of a lignin derivative and the meltability which contributes to the impregnation property to a base material etc., or the solubility to a solvent can be highly compatible. As a result, the base material or the like can be reliably impregnated while maintaining the reactivity of the lignin derivative, so that the lignin derivative can be effectively used as a resin raw material. That is, a lignin derivative suitable for a resin raw material can be obtained. In addition, according to this invention, the lignin derivative which has such a characteristic can be manufactured efficiently and reliably.

  When the ratio falls below the lower limit, a reaction site that causes a crosslinking reaction by the action of a general curing agent or a reaction site for introducing a reactive group is substituted with an aliphatic group, and Since the familiarity is deteriorated, when the lignin derivative is used as a resin raw material, the impregnation property to the base material may be lowered. On the other hand, when the ratio exceeds the upper limit, the meltability of the lignin derivative or the solubility in the solvent is remarkably reduced, and when used as a resin raw material, the mechanical properties such as elongation at the time of bending fracture are reduced. Or may be difficult to use as a resin raw material.

In addition, since aromatic protons and aliphatic protons have peaks at distant positions in the chemical shift spectrum of ¹ H-NMR analysis, peaks can be separated, and peak identification and integral calculation are performed. be able to.

  Specifically, when tetramethylsilane is used as a reference substance for analysis, generally, a peak attributed to an aromatic proton is located in the vicinity of 6 to 8 ppm. In addition, the peak attributed to the aliphatic proton is located in the vicinity of 0.5 to 5 ppm.

  On the other hand, the lignin secondary derivative of the present invention is obtained by introducing a reactive group into the lignin derivative of the present invention as described above. Since such a lignin secondary derivative has various reactive groups, it can be crosslinked at a high density and is useful as a resin raw material.

  The reactive group possessed by the lignin secondary derivative is a reactive atomic group, is self-reactive, and can react with two or more of the same reactive groups, or react with other functional groups. There is no particular limitation as long as it can be obtained. Specific examples include a vinyl group having a carbon-carbon unsaturated bond, an ethynyl group, and a maleimide group, as well as an epoxy group, a cyanate group, and an isocyanate group. Moreover, an epoxy group is preferably used. The lignin secondary derivative having an epoxy group is useful as a resin raw material that can replace a general epoxy resin.

<Method for producing lignin derivative and method for producing lignin secondary derivative>
Next, the manufacturing method of the lignin derivative of this invention and the manufacturing method of a lignin secondary derivative are demonstrated.

  In the method for producing a lignin derivative of the present invention, biomass is adjusted to a certain size, then placed in the presence of a mixed solvent containing water and an aprotic polar solvent, and these are decomposed under high temperature and high pressure. A decomposition step, and a distillation step of distilling off the aprotic polar solvent from the treated product obtained in the decomposition step to obtain a lignin derivative as an insoluble matter in the residue.

Hereinafter, each process will be described sequentially.
[1]
First, biomass is placed in the presence of a solvent.

  Although what was mentioned above is mentioned as biomass, Although the shape is not specifically limited, It is set as a block shape, a chip shape, a powder form etc.

  Moreover, it is preferable that the magnitude | size of the biomass used for this invention is about 100 micrometers-1 cm, and it is more preferable that it is about 200-1000 micrometers. By using biomass of such a size, it is possible to improve the dispersibility of the biomass in the liquid and to efficiently perform the biomass decomposition treatment.

  As a solvent used in the decomposition step, a mixed solvent of water and an aprotic polar solvent is used. Among these, as water, for example, ultrapure water, pure water, distilled water, ion exchange water, or the like is used.

  On the other hand, examples of the aprotic polar solvent include ketones such as methyl ethyl ketone, cyclic ethers such as tetrahydrofuran and dioxane, nitriles such as acetonitrile, N, N-dimethylformamide, N, N-dimethylacetamide, Examples include amides such as n-methylpyrrolidone, alkyl halides such as methylene chloride and chloroform, and a combination of one or more of these is used. Among these, at least one of ketones and cyclic ethers is preferably used from the viewpoint of biomass decomposition efficiency and the like.

  In addition, since the aprotic polar solvent is compatible with water, the mixed solvent has high homogeneity and can be efficiently decomposed.

  The reason why the efficiency of the decomposition treatment can be improved by using water and an aprotic polar solvent in combination has not been clarified yet, but only one of water and the aprotic polar solvent is sufficient for efficiency. Can't get. That is, high efficiency can be obtained only when both are used together. From this result, it is considered that water and aprotic polar solvent act synergistically under high temperature and high pressure to decompose biomass.

  In addition, in the past, multiple decomposition treatments were required, but by using water and an aprotic polar solvent in combination, the yield of the lignin derivative was sufficiently increased even with a single decomposition treatment. be able to. Thereby, cost reduction of a decomposition process can be achieved.

  Here, the aprotic polar solvent preferably has a boiling point lower than that of water. By using such an aprotic polar solvent, only the aprotic polar solvent can be easily distilled off from the mixed solvent with water, and the later-described distillation step can be easily performed.

  In this case, the difference in boiling point between water and the aprotic polar solvent is not particularly limited, but is preferably about 5 to 60 ° C, more preferably about 10 to 50 ° C, and about 20 to 50 ° C. More preferably. If the difference in boiling points is within the above range, the lignin derivative that is finally isolated can be reliably separated from water and the aprotic polar solvent in the distillation step described later while maintaining compatibility. Can be highly purified.

  The amount of the mixed solvent used is preferably as much as possible with respect to biomass, but is preferably about 1 to 20 times by mass, more preferably about 2 to 10 times by mass with respect to biomass. Thus, the amount of the mixed solvent necessary and sufficient for the biomass decomposition treatment is obtained.

  Further, the mixing ratio of water and aprotic polar solvent in the mixed solvent is not particularly limited, but when the amount of water is 1, the amount of aprotic polar solvent is about 0.2 to 5 by mass ratio. The ratio is preferably about 0.3 to 3, and more preferably about 0.3 to 3. Thereby, a lignin derivative can be efficiently and reliably isolated from biomass.

  Further, the mixed solvent may contain other solvents in addition to water and the aprotic polar solvent. The content of the other solvent in the mixed solvent is less than each of water and the aprotic polar solvent, and is 10% by mass or less of the mixed solvent, and is preferably 5% by mass or less.

  Examples of the other solvent include alcohols such as methanol and ethanol, phenols such as phenol and cresol, and the like, or a combination of one or more of these is used.

  Next, the biomass placed in the presence of the solvent is decomposed under high temperature and pressure (decomposition process). Thereby, biomass is decomposed into lignin, cellulose, hemicellulose, and other reactants.

  In the generation of a high temperature and high pressure environment, a pressure vessel such as an autoclave is used. Moreover, as this pressure vessel, what is equipped with a heating means and a stirring means is used preferably, and it is preferable to stir biomass under high temperature and pressure. Moreover, you may provide the means to pressurize independently from the factor which influences pressure, such as the temperature in a container, as needed. Examples of such means include means for introducing an inert gas such as argon gas into the container.

  As for the conditions in the decomposition treatment, the treatment temperature is preferably 150 to 350 ° C, more preferably 200 to 300 ° C. When the treatment temperature is within the above range, the molecular weight of the lignin derivative obtained after decomposition can achieve both reactivity and meltability or solubility. In addition, when processing temperature is less than the said lower limit, the molecular weight of a lignin derivative becomes higher than necessary, and there exists a possibility that it may be inferior to solubility and a meltability. On the other hand, when the treatment temperature exceeds the upper limit, the molecular weight of the lignin derivative becomes unnecessarily low, and the reactivity may decrease when used as a resin raw material.

  Moreover, it is preferable that the processing time in a decomposition process is 480 minutes or less, and it is more preferable that it is 30 to 120 minutes. If the treatment time is within the above range, the ratio of aromatic protons and aliphatic protons of the lignin derivative obtained after decomposition is an appropriate value, and optimization is performed from the viewpoint of compatibility between reactivity and meltability or solubility. Can do.

  Furthermore, the pressure in the decomposition treatment is preferably 1 to 8 MPa, and more preferably 1.5 to 5 MPa. When the pressure is within the above range, the biomass decomposition efficiency can be significantly increased, and the processing time can be shortened accordingly. If necessary, the pressure inside the pressure vessel may be increased with argon gas or the like to increase the pressure.

  In addition, you may make it add the catalyst which accelerates | stimulates a decomposition process to a solvent as needed. Examples of the catalyst include inorganic bases such as sodium carbonate.

  Furthermore, as a pretreatment for the decomposition step, it is preferable to perform a step in which the biomass and the solvent are sufficiently agitated to allow them to blend. Thereby, the decomposition of biomass can be particularly optimized.

  In addition, as stirring temperature, it is preferable that it is about 0-150 degreeC, and it is more preferable that it is about 10-130 degreeC.

  Moreover, as stirring time, it is preferable that it is about 1 to 120 minutes, and it is more preferable that it is about 5 to 60 minutes.

  Further, examples of the stirring method include various mills such as a ball mill and a bead mill, a method using a stirrer equipped with a stirring blade, a method using water flow stirring using a homogenizer, a jet pump, and the like.

  The solvent used in the decomposition step is preferably used in a subcritical or supercritical state (condition). It is considered that the solvent in the subcritical or supercritical state contributes to the acceleration of the biomass decomposition process. For this reason, the efficiency of a decomposition process can be improved more, the manufacturing cost of a lignin derivative can be reduced, and the manufacturing process can be simplified.

  Furthermore, since the solvent used in the decomposition step is a mixed solvent of water and an aprotic polar solvent as described above, it is preferable that both the water and the aprotic polar solvent are in a subcritical or supercritical state. However, a sufficient effect can be obtained even if either one is in a subcritical or supercritical state.

  As an example, the critical temperature of water is about 374 ° C., the critical pressure is about 22.1 MPa, the critical temperature of acetonitrile is about 272 ° C., and the critical pressure is about 4.8 MPa.

[2]
Next, the processed product obtained in the decomposition step is separated by filtration into a filtrate and a decomposition residue derived from cellulose (filtration step). Further, the aprotic polar solvent is distilled off from the obtained filtrate (distillation step). The residue resulting from the distillation of the aprotic polar solvent is separated into water and insoluble matter. This insoluble matter is a lignin derivative. Therefore, a lignin derivative can be obtained as a recovered product by recovering insolubles from the residue. A method such as filtration, heat dehydration, or vacuum dehydration is used to recover the insoluble matter.
By the above method, a lignin derivative can be produced with high yield.

[3]
In addition, the method for producing a lignin secondary derivative of the present invention includes a reactive group that introduces a reactive group into a lignin derivative by mixing a processed biomass and a compound containing a reactive group after the distillation step. It has an introduction process.

  As a method for introducing a reactive group, for example, a method of mixing a lignin derivative and a compound containing a reactive group is used. And after mixing, a reactive group is introduce | transduced into a lignin derivative by adding a catalyst etc. as needed.

  Specifically, when introducing an epoxy group, it can be introduced by mixing a lignin derivative, epichlorohydrin and a solvent, and adding a base catalyst such as sodium hydroxide to the mixture under reflux under reduced pressure.

  In addition, when introducing a vinyl group, a lignin derivative, a halogen compound containing a vinyl group such as an allyl halide or a vinylbenzyl halide, and a solvent are mixed, and a base catalyst such as sodium hydroxide is added to the mixture under heating and stirring. Can be introduced.

  In addition, when introducing an ethynyl group, a lignin derivative, a halogen compound containing an ethynyl group such as a propargyl halide or a phenylacetylene halide, and a solvent are mixed, and a base catalyst such as sodium hydroxide is added to the mixture with heating and stirring. Can be introduced.

  Moreover, when introduce | transducing a cyanate group, it can introduce | transduce by mixing a lignin derivative, halogenated cyanate, and a solvent, and adding a base catalyst, such as sodium hydroxide, to this under heating stirring.

  When introducing a maleimide group, a lignin derivative and parachloronitrobenzene are mixed. As a result, the maleimide group reacts with the phenolic hydroxyl group of the lignin derivative to obtain a polynitrated lignin bonded via an ether bond. Subsequently, polynitrated lignin is reduced to be converted to polyaminated lignin, and further reacted with maleic anhydride to obtain a lignin secondary derivative having a maleimide group introduced.

Moreover, when introduce | transducing an isocyanate group, the hydroxyl group in a lignin derivative is converted into a carboxyl group by mixing a lignin derivative and maleic anhydride. Thereafter, the mixture is heated in the presence of diphenyl phosphate azide to obtain a lignin secondary derivative having an introduced isocyanate group.
A lignin derivative and a lignin secondary derivative can be produced as described above.

<Lignin resin composition>
By using the above lignin derivative and lignin secondary derivative, a lignin resin composition as a resin raw material can be obtained.

Hereinafter, the lignin resin composition will be described.
The lignin resin composition contains at least one of a lignin derivative and a lignin secondary derivative and a crosslinking agent. The lignin derivative and the lignin secondary derivative are cured by a crosslinking reaction caused by the action of the crosslinking agent. As a result, a resin product can be produced from the lignin resin composition.

  The crosslinking agent is not particularly limited as long as it is a crosslinking agent that causes a crosslinking reaction in the phenolic hydroxyl group or reactive group of the lignin derivative and lignin secondary derivative.

  Specifically, as a crosslinking agent that causes a crosslinking reaction to a phenolic hydroxyl group, for example, an orthocresol novolac epoxy resin, an epoxy resin such as a bisphenol A type epoxy resin, a urethane resin such as hexamethylene diisocyanate, toluene diisocyanate, Compounds that can be cross-linked by electrophilic substitution reaction on the aromatic ring of lignin derivatives include aldehydes such as formaldehyde, acetaldehyde and paraformaldehyde, aldehyde sources such as polyoxymethylene, hexamethylenetetramine, and resol type phenol. Examples of the conventional phenol resin such as a resin include a known crosslinking agent and a compound that can be crosslinked by electrophilic substitution reaction on the aromatic ring of the lignin derivative. In addition, hexamethylenetetramine is preferably used from the viewpoint of reactivity and availability.

  On the other hand, the cross-linking agent that causes a cross-linking reaction to the reactive group of the lignin secondary derivative may be any cross-linking agent that reacts with the reactive group or has a self-crosslinking reactive group. When the reactive group in the lignin secondary derivative is an epoxy group, for example, a phenol resin such as a novolak type phenol resin, a lignin compound having a phenolic hydroxyl group, diethylenetriamine, m-xylylenediamine, N-aminoethyl General epoxy compounds such as amine compounds such as piperazine, acid anhydrides such as phthalic anhydride, succinic anhydride and maleic anhydride, dicyandiamide, guanidines, 2-methylimidazole and 2-ethyl-4-methylimidazole Examples include a curing agent for resin. Examples of the crosslinking agent having a self-crosslinkable reactive group include imidazoles such as 2-methylimidazole and 2-ethyl-4-methylimidazole, 1,8-diazabicyclo (5,4,0) undecene. Anionic polymerization initiators such as -7, cationic systems such as triphenylsulfonium hexafluorophosphate, sulfonium salts such as diphenylsulfonium tetrafluoroborate, phenyldiazonium hexafluorophosphate, diazonium salts such as phenyldiazonium tetrafluoroborate A polymerization initiator etc. are mentioned, Among these, the 1 type, or 2 or more types of mixture is used. Among these, lignin compounds are preferably used from the viewpoint of reactivity and the like.

  Further, when the reactive group in the lignin secondary derivative is an isocyanate group, examples of the crosslinking agent include general curing agents for isocyanate resins such as phenol resins, lignin degradation products, polyvinyl alcohol, and polyamine compounds. One or a mixture of two or more of these is used.

  When the reactive group in the lignin secondary derivative is a vinyl group, examples of the crosslinking agent include anionic polymerization initiators such as butyl lithium and sodium ethoxide, azobisisobutyronitrile (AIBN), Examples thereof include polymerization initiators of general vinyl group-containing compounds such as radical polymerization initiators such as benzoyl peroxide (BPO), and one or a mixture of two or more of these are used.

  Further, when the reactive group in the lignin secondary derivative is an ethynyl group, as a crosslinking agent, for example, a polymerization catalyst of a general ethynyl group-containing compound such as molybdenum pentachloride, tungsten pentachloride, norbornadiene rhodium chloride dimer or the like can be used. Among them, one or a mixture of two or more of these is used.

  In addition, when the reactive group in the lignin secondary derivative is a maleimide group, examples of the crosslinking agent include polymerization of general maleimide group-containing compounds such as peroxides such as BPO and the aforementioned anionic polymerization initiators. An initiator is mentioned, The mixture of 1 type, or 2 or more types of these is used.

  Further, when the reactive group in the lignin secondary derivative is a cyanate group, examples of the crosslinking agent include polymerization catalysts for general cyanate group-containing compounds such as metal catalysts such as cobalt naphthenate, and the like. Among them, one kind or a mixture of two or more kinds is used.

  In the lignin resin composition, the content of the lignin derivative or lignin secondary derivative is preferably 40 to 95 parts by weight, and more preferably 50 to 90 parts by weight. Moreover, it is preferable that content of a crosslinking agent is 5-60 weight part, and it is more preferable that it is 10-50 weight part.

In addition to the above-mentioned components, the lignin resin composition may contain an alkali metal salt such as methoxy sodium or t-butoxy potassium, an alkaline earth metal salt such as calcium acetate, Na ₂ O, K ₃ , if necessary. A hardening accelerator such as an alkali metal oxide such as O ₂ or an alkaline earth metal oxide such as CaO or BaO may be included.

  In particular, when a lignin secondary derivative having an epoxy group as a reactive group is included, for example, imidazoles such as 2-methylimidazole and 2-ethyl-4-methylimidazole, 1,8-diazabicyclo (5, 4,0) undecene-7, tris (dimethylaminomethyl) phenol, tertiary amines such as benzyldimethylamine, triphenylphosphine, tetra-n-butylphosphonium tetraphenylborate and the like may be contained.

Moreover, when the lignin secondary derivative which has a vinyl group, an ethynyl group, a maleimide group, a cyanate group etc. as a reactive group is included, the said polymerization initiator may be included, for example.
Furthermore, the additive mentioned later may be included as other components.

  Examples of such additives include silane coupling agents such as epoxy silane, mercapto silane, amino silane, alkyl silane, ureido silane, and vinyl silane, titanate coupling agents, aluminum coupling agents, and aluminum / zirconium coupling agents. Various coupling agents, colorants such as carbon black, bengara, polyethylene wax, higher fatty acid esters, fatty acid amides, ketones and amines, synthetic waxes such as hydrogenated oils, natural waxes such as paraffin wax and montan wax, Higher fatty acids such as stearic acid and zinc stearate and metal salts thereof, mold release agents such as paraffin, silicone oil, low stress components such as silicone rubber, antimony trioxide, aluminum hydroxide, Examples include magnesium oxide, zinc borate, zinc molybdate, flame retardants such as phosphazene, inorganic ion exchangers such as bismuth oxide hydrate, and a combination of one or more of these is used. It is done.

  When the lignin resin composition contains a release agent, the content of the release agent is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the lignin derivative or lignin secondary derivative. More preferably, it is 1 to 5 parts by weight. In addition, when the content of the release agent is less than the above, when the lignin resin composition is filled in a mold and molded, the mold release property may be insufficient, whereas the content of the release agent If the value exceeds the upper limit, the curability of the lignin resin composition may be reduced.

  Such a lignin resin composition can be obtained, for example, by uniformly mixing at least one of a lignin derivative and a lignin secondary derivative, a crosslinking agent, and other components added as necessary with a mixer. It is done. If necessary, the obtained mixture may be heated, melted and fused at a temperature lower than the temperature at which the mixture is cured using a hot plate, a kneader such as a pressure kneader, a roll, a kneader, or a twin screw extruder. Good. The specific heating temperature varies slightly depending on the composition to be selected, but is preferably about 50 to 100 ° C.

  Further, when a molded body is obtained by molding a lignin resin composition, it is preferable to prepare a molding material in which a filler is added to the lignin resin composition and to mold it using this.

  Examples of the filler include inorganic fillers such as fused silica, crystalline silica, clay, alumina, mica, and glass fiber, and organic fillers such as wood powder, pulp, pulverized cloth, and thermosetting resin cured powder. One or more of these can be used, but is not limited thereto.

  In this case, the content of the filler is preferably 10 to 900 parts by weight and more preferably 20 to 500 parts by weight with respect to 100 parts by weight of the lignin resin composition.

  Such a molding material can be obtained, for example, by uniformly mixing a lignin resin composition, a filler, and other components added as necessary with a mixer. If necessary, the obtained mixture may be heated and mixed, kneaded, etc., and crushed after cooling to form a granular molding material.

  The obtained molding material is molded by a desired molding method, and a resin product can be produced by curing the molding material. Examples of the molding method include transfer molding, injection molding, and compression molding.

  The molding temperature is preferably about 150 to 220 ° C., and the molding time is preferably about 1 to 5 minutes. These conditions are appropriately adjusted according to the purpose.

  Examples of the resin product obtained include semiconductor parts, aircraft parts, automobile parts, industrial machine parts, electronic parts, electrical parts, mechanical parts, and the like.

<Prepreg>
Next, the prepreg manufactured using the lignin resin composition described above will be described.
The prepreg is obtained by impregnating a base material with a lignin resin composition.

  Examples of the base material include glass fiber base materials such as glass woven fabric and glass non-woven fabric, paper materials such as kraft paper and linter paper, cotton fibers, hemp fibers, aramid fibers, polyester fibers, acrylic fibers, etc. Examples include organic synthetic fiber base materials composed of woven or non-woven fabrics such as natural fibers or synthetic fibers, inorganic fiber base materials composed of woven or non-woven fabrics such as metal fibers, carbon fibers and mineral fibers, or mats thereof. . In addition, you may make it use the raw material fiber of these base materials individually or in mixture.

  Such a prepreg is manufactured, for example, by impregnating a base material with a lignin resin composition and then drying. At this time, the lignin resin composition is used as a varnish dissolved in an organic solvent, but may be used by a method such as melt impregnation in a solvent-free powder state.

  Examples of the method of impregnating the base material with the lignin resin composition include a method of immersing the base material in the varnish, a method of applying the varnish with various coaters, and a method of spraying the varnish by spraying.

  In addition, in the prepreg obtained by drying, it is preferable that 80 mass% or more of the organic solvent used for the varnish is volatilized.

  In the above drying, the drying conditions are not particularly limited, but the drying temperature is preferably about 80 to 180 ° C., and the drying time is freely selected according to the desired prepreg characteristics in consideration of the gelation time of the varnish. The

  Further, the resin impregnation rate in the prepreg is represented by the ratio of the total mass of the lignin derivative and the lignin secondary derivative and the crosslinking agent with respect to the total mass of the prepreg, and is preferably about 30 to 80% by mass, It is more preferable that the amount is about 70% by mass. These ratios are appropriately adjusted according to the intended performance of the prepreg, the thickness of the insulating layer in the substrate obtained by laminating the prepreg, and the like. The amount of impregnation of the varnish is preferably set so that the solid content in the varnish occupies 35 to 75% by mass with respect to the total amount of the solid content in the varnish and the base material.

<Resin plate>
Next, the resin plate (composite structure) will be described.

  The resin plate is manufactured by curing a laminate formed by laminating one or two or more prepregs as described above.

  Specifically, it is produced by curing a lignin derivative and a lignin secondary derivative while forming a prepreg or a laminate thereof into a substrate by heat and pressure molding.

  The temperature at the time of heating and pressing is preferably about 100 to 280 ° C, more preferably about 120 to 250 ° C. Further, the pressure is preferably about 0.5 to 20 MPa, and more preferably about 1 to 8 MPa.

  Moreover, if it is such a method, it can form in arbitrary shapes with the metal mold | die at the time of shaping | molding, and the obtained resin board (composite structure) is electric / electronic materials, structural materials, such as a printed circuit board. It is preferably used as a building material or an insulating material.

  As an electric / electronic material application such as the printed circuit board, metal foil is laminated on one side or both sides of a prepreg or a laminate thereof before heat and pressure molding, and these are heat and pressure molded to form a metal tension. A substrate (metal-clad laminate) can be manufactured. Furthermore, in this metal-clad substrate, a printed wiring board provided with a circuit can be manufactured by processing the metal layer into a predetermined shape.

  As the metal foil, copper foil or aluminum foil is generally used. Moreover, the average thickness shall be about 5-200 micrometers.

  The metal foil includes an intermediate layer made of a metal material such as nickel, nickel-phosphorus, nickel-tin alloy, nickel-iron alloy, lead, lead-tin alloy, and an average thickness provided on both surfaces thereof. A composite foil having a three-layer structure having a copper layer having a thickness of 0.5 to 15 μm and a copper layer having an average thickness of 10 to 300 μm, or a two-layer structure composite foil in which an aluminum foil and a copper foil are combined is used. Also good.

  The resin plate thus obtained is applied to, for example, a printed wiring board, a mother board, a semiconductor plastic package, and the like.

  On the other hand, as applications other than the printed wiring boards, motherboards, and substrates for electrical and electronic materials such as plastic packages for semiconductors, structural materials such as automobile interior materials, building materials such as interior materials for houses and office buildings, switchboards, etc. Applies to insulation materials used in

  Although the present invention has been described above, the present invention is not limited to this. For example, in the method for producing a lignin derivative and the method for producing a lignin secondary derivative, any desired process may be added.

Next, specific examples of the present invention will be described.
1. Manufacture of laminate (Sample No. 1)
<Production of lignin derivative>
15 g of cedar wood flour (60 mesh under) and 80 g of a mixed solvent obtained by mixing pure water and methyl ethyl ketone at a mass ratio of 1: 1 were introduced into a 300 ml autoclave and the contents were stirred while stirring at 300 rpm. As a treatment, the mixture was stirred at room temperature for 15 minutes to sufficiently blend the cedar wood powder and the mixed solvent, and then treated at 3 MPa and 200 ° C. for 60 minutes to decompose the cedar wood powder. The pressure was adjusted by pressurization by blowing argon gas. The decomposition product removed the residue by filtration. Subsequently, after methyl ethyl ketone (boiling point 80 ° C.) was distilled off from the treated product, the residue was filtered and washed with pure water to separate the insoluble part. This insoluble part was dried to obtain 3 g of a lignin derivative.

About what was obtained here, when it used for the ¹ H-NMR analysis, in the spectrum of the chemical shift which used tetramethylsilane as the reference substance of 0 ppm, a plurality of peaks attributed to the aromatic proton at 6 to 8 ppm are 0 A plurality of peaks attributed to aliphatic protons were observed at 5 to 3 ppm.

  Therefore, for each detected peak, the integrated value of the plurality of peaks attributed to the aromatic proton was set to 1, and the integrated value of the plurality of peaks attributed to the aliphatic proton was 3.97. That is, the integrated value of the plurality of peaks attributed to the aromatic protons was 25% of the integrated value of the plurality of peaks attributed to the aliphatic protons.

  The molecular weight of the lignin derivative obtained above was measured by gel permeation chromatography in terms of polystyrene using tetrahydrofuran as an eluent. The number average molecular weight (Mn) = 600 and the molecular weight distribution (Mw / Mn) = 1. 3.

<Manufacture of lignin resin composition>
Next, 10 parts by mass of hexamethylenetetramine was added to 90 parts by mass of the obtained lignin derivative at room temperature to obtain a lignin resin composition.

<Manufacture of varnish for substrate impregnation>
And the lignin resin composition obtained above was diluted with methanol, and the resin varnish for base-material impregnation with a resin content of 50 mass% was obtained.

<Manufacture of prepreg and resin plate>
Next, the varnish for impregnating the base material obtained above with a dip coater device with respect to kraft paper (basis weight 135 g / m ² ) so that the resin impregnation rate is 55 mass% (ratio to the whole prepreg). It was coated and then dried at 160 ° C. for 5 minutes to obtain a prepreg. Eight prepregs thus produced were stacked and subjected to heat and pressure molding at 200 ° C. and 5 MPa for 10 minutes. Thereby, a laminated plate (resin plate) having an average thickness of 1.6 mm was obtained.

(Sample Nos. 2 to 13)
Except for changing the type of biomass, solvent, temperature, pressure, and time in the decomposition treatment as shown in Table 1, sample No. A lignin derivative was obtained in the same manner as in Example 1, and a laminate was obtained.

In addition, each sample No. For the lignin derivative, the chemical shift spectrum by ¹ H-NMR analysis was obtained, and the ratio of the integrated value of the plurality of peaks belonging to the aromatic proton to the integrated value of the plurality of peaks belonging to the aliphatic proton is shown in Table 1. Indicated.

  Further, each sample No. The number average molecular weight (Mn) of the lignin derivative was measured and shown in Table 1.

(Sample No. 14)
<Production of lignin derivative>
10 g of cedar wood flour was placed in a 500 ml beaker, methanol solution of p-cresol (containing 3 mol times of phenol derivative per lignin constituent unit) was added, stirred with a glass rod, and allowed to stand for 24 hours. Thereafter, methanol was completely distilled off to obtain p-cresol sorption wood flour. To this wood flour, 100 ml of 72 mass% sulfuric acid was added and stirred vigorously at 30 ° C. for 1 hour, and then the mixture was poured into a large excess of water, the insoluble matter was recovered, deacidified and dried to give a lignin derivative. Got.

About the obtained lignin derivative, the spectrum of the chemical shift by ¹ H-NMR analysis was acquired, and the ratio of the integrated value of the plurality of peaks attributed to the aromatic proton to the integrated value of the plurality of peaks attributed to the aliphatic proton was expressed. It was shown in 2.
The number average molecular weight (Mn) of the obtained lignin derivative was measured and shown in Table 2.

<Manufacture of lignin resin composition>
Next, 10 parts by mass of hexamethylenetetramine was added to 90 parts by mass of the obtained lignin derivative at room temperature to obtain a lignin resin composition.

<Manufacture of varnish for substrate impregnation>
Next, the lignin resin composition obtained above was diluted with methanol to obtain a resin varnish for substrate impregnation having a resin content of 50% by mass.

<Manufacture of prepreg and resin plate>
Next, the resin varnish for impregnating the base material obtained above was applied to kraft paper with a dip coater so that the resin content was 55% by mass (ratio to the whole prepreg), and then 160 ° C. And dried for 5 minutes to obtain a prepreg. Eight prepregs thus produced were stacked and subjected to heat and pressure molding at 200 ° C. and 5 MPa for 10 minutes. However, the laminated board could not be formed due to insufficient melting.

(Sample No. 15)
Sample No. was changed except that the type of biomass was changed as shown in Table 2. In the same manner as in the case of 14, a lignin derivative was obtained and a prepreg was obtained. However, the laminated sheet could not be formed due to insufficient melting during molding.

(Sample No. 16-23)
Except for changing the type of biomass, the solvent, the temperature, the pressure and the time in the decomposition treatment as shown in Table 2, sample No. A lignin derivative was obtained in the same manner as in Example 1, and a laminate was obtained.

In addition, each sample No. The chemical shift spectrum obtained by ¹ H-NMR analysis was obtained for the lignin derivative, and the ratio of the integrated value of the plurality of peaks belonging to the aromatic proton to the integrated value of the plurality of peaks belonging to the aliphatic proton is shown in Table 2. Indicated.

  Further, each sample No. The number average molecular weight (Mn) of the lignin derivative was measured and shown in Table 2.

(Sample No. 24)
Except that the epoxy group was introduced into the lignin derivative by the following steps to produce a lignin secondary derivative and a laminate was produced using this, sample No. Same as 1.

<Production of secondary lignin derivative>
First, in a three-necked flask equipped with a stirrer and a cooling pipe, a sample No. 1 lignin derivative and 100 g of epichlorohydrin were introduced and refluxed under reduced pressure under a pressure of 100 mmHg (1.3 × 10 ⁴ Pa), 2 g of a 20% strength by weight aqueous sodium hydroxide solution was added over 30 minutes. And dripped. Thereafter, the reaction mixture was obtained by maintaining the reduced-pressure reflux state for 90 minutes.

  Next, the insoluble matter was removed from the reaction product by filtration, and the epichlorohydrin soluble portion was isolated. And epichlorohydrin was distilled off from this epichlorohydrin soluble part, and 0.8g of lignin secondary derivatives were obtained by drying.

<Manufacture of varnish for substrate impregnation>
Subsequently, the lignin secondary derivative obtained above was diluted with methanol to obtain 790 g of a lignin secondary derivative varnish having a resin content of 50% by mass.

  And 100 mass parts of lignin secondary derivative varnishes and 2 mass parts of 2-methylimidazole were added, and the resin varnish for base material impregnation was obtained.

<Manufacture of prepreg and resin plate>
Next, the varnish for impregnating the base material obtained above with a dip coater device with respect to kraft paper (basis weight 135 g / m ² ) so that the resin impregnation rate is 55 mass% (ratio to the whole prepreg). It was coated and then dried at 160 ° C. for 5 minutes to obtain a prepreg. Eight prepregs thus produced were stacked and subjected to heat and pressure molding at 200 ° C. and 5 MPa for 10 minutes. As a result, a laminate having an average thickness of 1.6 mm was obtained.

(Sample No. 25-29)
Except for changing the type of lignin derivative and the type of reactive group to be introduced as shown in Table 3, sample No. In the same manner as in the case of 24, a lignin secondary derivative was obtained and a laminate was obtained. In addition, No. Regarding No. 27, the laminated plate could not be formed due to insufficient melting during molding.

  Moreover, about the sample which used the vinyl group as a reactive group, it replaced with epichlorohydrin and allyl bromide was used, and it replaced with 2-methylimidazole and used azobisisobutyronitrile.

2. 2. Evaluation of lignin derivative 2.1 Evaluation of gel time 15 g of hexamethylenetetramine was added to 100 g of the lignin derivative, and the gel time (gelation time) at 150 ° C. was measured for this sample in accordance with the method specified in JIS K 6910. The results are shown in Tables 1 and 2 It was.

  As is clear from Tables 1 and 2, it was recognized that in each example, a lignin derivative (preferably about 30 to 190) having a gel time value not too low and not too high as compared with each comparative example was obtained. . Therefore, according to the manufacturing method of the lignin derivative of this invention, it became clear that the lignin derivative which can make reactivity and meltability or solubility highly compatible can be manufactured.

3. Evaluation of laminated board 3.1 Evaluation of substrate impregnation 1 ml of the resin varnish used in the above was dropped onto the kraft paper surface with a dropper. After air-drying at room temperature, it was confirmed whether it penetrated to the back of the kraft paper.

<Evaluation criteria for substrate impregnation>
○: Penetrating to the back of the kraft paper ×: Insufficient penetration of the back of the kraft paper

3.2 Evaluation of elongation at bending fracture Sample No. The laminated plate was subjected to a bending test until it broke according to the method defined in JIS-C6481. And the ratio (elongation at the time of bending fracture | rupture) of the change of the dimension after a test with respect to the dimension before a test was evaluated according to the following evaluation criteria.

<Evaluation criteria for elongation at bending fracture>
○: Elongation at bending fracture is 1% or more ×: Elongation at bending fracture is less than 1% Above, the evaluation results of 3.1, 3.2 are shown in Tables 1-3.

  The laminates obtained in each example were found to have high substrate impregnation properties, that is, high uniformity of the resin varnish with respect to kraft paper, and excellent elongation at the time of bending fracture. This is because each sample No. used in the production of the laminated plate was obtained. The lignin derivative is produced by the production method of the present invention. As a result, the content of aromatic protons in the lignin derivative is within a predetermined range, so that the reactivity and meltability or solubility of the lignin derivative are optimized. It is thought that this is because.

  On the other hand, the laminates obtained in the respective comparative examples included those inferior in substrate impregnation properties and those inferior in elongation at the time of bending fracture (brittle).

Claims (10)

A method for producing a lignin derivative obtained by decomposing biomass,
A decomposition step of placing biomass in the presence of a mixed solvent containing water and an aprotic polar solvent and decomposing them under high temperature and high pressure;
And a distillation step of distilling off the aprotic polar solvent from the treated product obtained in the decomposition step to obtain a lignin derivative as an insoluble matter in the residue.   2. The method for producing a lignin derivative according to claim 1, wherein the decomposition step is a decomposition treatment at a treatment temperature of 150 to 350 ° C., a treatment pressure of 1 to 8 MPa, and a treatment time of 480 minutes or less.   The method for producing a lignin derivative according to claim 1 or 2, wherein the decomposition step is performed under subcritical conditions of water or an aprotic polar solvent.   The method for producing a lignin derivative according to any one of claims 1 to 3, wherein the aprotic polar solvent has a boiling point lower than that of water.   The method for producing a lignin derivative according to claim 4, wherein the difference in boiling point between water and the aprotic polar solvent is 5 to 60 ° C.   The method for producing a lignin derivative according to any one of claims 1 to 5, wherein the aprotic polar solvent is at least one of ketones and cyclic ethers. A method for producing a lignin secondary derivative obtained by introducing a reactive group into a lignin derivative obtained by decomposing biomass,
A decomposition step of placing biomass in the presence of a mixed solvent containing water and an aprotic polar solvent and decomposing them under high temperature and high pressure;
A distillation step of distilling off the aprotic polar solvent from the treated product obtained by the decomposition step;
A method for producing a lignin secondary derivative, comprising: a reactive group introducing step of mixing the treated product obtained in the distillation step and the compound containing the reactive group.   The method for producing a lignin secondary derivative according to claim 7, wherein the reactive group is an epoxy group.   A lignin derivative produced by the method for producing a lignin derivative according to any one of claims 1 to 6.   A lignin secondary derivative produced by the method for producing a lignin secondary derivative according to claim 7 or 8.