JP5754169B2 - Lignin derivative, lignin secondary derivative, lignin resin composition, prepreg and composite structure - Google Patents

Description

  The present invention relates to a lignin derivative, a lignin secondary derivative, a lignin resin composition, a prepreg, and a composite structure.

  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, since the lignin derivative produced by the method as described above has low meltability and solubility, when impregnating a base material or the like, the impregnation property is poor. Further, such a lignin derivative has a problem that it is brittle even when it is cross-linked and cured and has low mechanical properties.

JP 2001-261839 A

  An object of the present invention is to provide a lignin derivative and a lignin secondary derivative excellent in reactivity and excellent in meltability or solubility in a solvent, a lignin resin composition and a machine containing these, and excellent in impregnation into a substrate. Another object of the present invention is to provide a prepreg capable of producing a resin plate excellent in mechanical properties (particularly elongation at bending fracture) and a resin plate (composite structure) formed by curing the prepreg.

Such an object is achieved by the present inventions (1) to (8) below.
(1) After pretreatment of stirring biomass and solvent at a temperature of 0 to 150 ° C. for a time of 1 to 120 minutes, the biomass is decomposed at a temperature of 200 to 380 ° C. for a time of 480 minutes or less and a pressure of 4 to 22 MPa. Manufactured by
When subjected to ¹ H-NMR analysis, the integrated value of the peak attributed to the aromatic proton in the obtained spectrum is 15 to 50% of the integrated value of the peak attributed to the aliphatic proton, Derivative.

  (2) The lignin derivative according to (1), wherein the lignin derivative is unsubstituted in at least one of an ortho-position and a para-position of the aromatic ring with respect to a hydroxyl group.

  (3) The said lignin derivative is a lignin derivative as described in said (1) or (2) whose polystyrene conversion number average molecular weights measured by gel permeation chromatography are 200-2000.

(4) A lignin secondary derivative obtained by introducing a reactive group into the lignin derivative according to any one of (1) to (3) above.
(5) The lignin secondary derivative according to (4), wherein the reactive group is an epoxy group.

  (6) It contains at least one of the lignin derivative according to any one of (1) to (3) above and the lignin secondary derivative according to claim 4 or 5, and a crosslinking agent. Lignin resin composition.

  (7) A prepreg obtained by impregnating a base material with the lignin resin composition described in (6) above.

  (8) A composite structure obtained by curing the prepreg according to (7).

  According to the present invention, a lignin derivative and a lignin secondary derivative excellent in reactivity and excellent in meltability or solubility in a solvent can be obtained. In addition, according to the present invention, a lignin resin composition excellent in impregnation into a substrate, a prepreg capable of producing a resin plate excellent in mechanical properties (particularly elongation at bending fracture), and the prepreg are cured. Thus obtained resin plate (composite structure) is obtained.

  Hereinafter, the lignin derivative, lignin secondary derivative, lignin resin composition, prepreg and composite structure of the present invention will be described in detail.

The lignin derivative of the present invention is obtained by decomposing biomass, and when subjected to ¹ H-NMR analysis, the integrated value of the peak attributed to the aromatic proton in the obtained spectrum is the aliphatic proton. It is characterized by being 15 to 50% of the integrated value of the attributed peak.

  The secondary lignin derivative of the present invention is obtained by introducing a reactive group into the above lignin derivative.

  The lignin resin composition of the present invention contains at least one of the above lignin derivative and the above lignin secondary derivative and a crosslinking agent, and the prepreg of the present invention is based on the above lignin resin composition. Is impregnated.

<Lignin derivative and lignin secondary derivative>
First, the lignin derivative and lignin secondary derivative of the present invention will be described.

  The lignin derivative and the lignin secondary derivative of the present invention 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 cypress, grasses such as bamboo and rice straw, and coconut shells.

  Such lignin derivatives and secondary lignin derivatives can be used as raw materials for various resin products. However, conventional lignin derivatives have low meltability and solubility, so that when impregnated into a substrate, the impregnation property is poor. That was a problem. In addition, these lignin derivatives and lignin secondary derivatives are brittle and have low mechanical properties even when cured with a resin. For this reason, it was difficult to utilize as a resin raw material.

Therefore, the present inventor has intensively studied the conditions for achieving both the reactivity that contributes to the mechanical properties of the cured resin of the lignin derivative and the meltability or solubility that contributes to the impregnation property to the base material. The present inventors have found that the bonding state of protons (hydrogen atoms) in the lignin derivative is a factor that greatly affects the reactivity, meltability, and solubility of the lignin derivative. Then, when the lignin derivative obtained by decomposing biomass is 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 peak attributed to the aliphatic proton. It has been found that the above-mentioned problem can be reliably solved if the integrated value is 15 to 50%, and the present invention has been completed. In other words, by optimizing the ratio of protons present as aromatic protons and protons present as aliphatic protons based on the chemical shift results of ¹ H-NMR analysis, excellent reactivity and excellent meltability Alternatively, it has been found that a resin raw material having a good balance between solubility can be easily specified.

  Further, the integral value of the peak attributed to the aromatic proton is 15 to 50% of the peak value attributed to the aliphatic proton, preferably about 15 to 45%, more preferably 20%. About 40%, more preferably about 20-35%.

  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, the impregnation property to the base material is remarkably lowered when used as a resin raw material. On the other hand, when the ratio exceeds the upper limit, when used as a resin raw material, mechanical properties such as elongation at the time of bending fracture are lowered, or it is 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.

  Here, the 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.

  In addition, the lignin derivative of 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 of 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.

  Moreover, as described above, the lignin secondary derivative of the present invention is obtained by introducing a reactive group into the lignin derivative of the present invention. 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, a method for producing the lignin derivative and the lignin secondary derivative of the present invention will be described.

  The lignin derivative of the present invention can be obtained by placing the aforementioned biomass in the presence of a solvent and decomposing it under high temperature and high pressure.

  Specifically, the biomass is adjusted to a certain size, then placed in the presence of a solvent and decomposed under high temperature and pressure, and the insoluble matter in the processed product obtained by the decomposition step is lignin. Has a soaking process in which the solvent is soluble in a solvent, and a distilling process in which the solvent in which the lignin is soluble is distilled from the soluble matter in the processed product obtained by the soaking process.

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.

  Examples of the solvent used in the decomposition step include water, alcohols such as methanol and ethanol, phenols such as phenol and cresol, ketones such as acetone and methyl ethyl ketone, dimethyl ether, ethyl methyl ether, diethyl ether, Ethers such as tetrahydrofuran, nitriles such as acetonitrile, amides such as N, N-dimethylformamide, and the like, and one or two or more of them are used as a mixed solvent.

  As the solvent, water is particularly preferably used. Thereby, the lignin derivative of this invention can be manufactured more reliably.

  As a usage-amount of a solvent, it is so good that it is large with respect to biomass, However, Preferably it is about 1-20 mass times with respect to biomass, and it is more preferable that it is about 2-10 mass times.

  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 400 ° C, and more preferably 200 to 380 ° 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 360 minutes. If the treatment time is within the above range, the ratio of aromatic protons to aliphatic protons of the lignin derivative obtained after decomposition becomes an appropriate value, and optimization is performed from the viewpoint of compatibility between reactivity and meltability or solubility. be able to.

  Furthermore, the pressure in the decomposition treatment is preferably 1 to 40 MPa, and more preferably 1.5 to 25 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.

  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 of sufficiently stirring the biomass and the solvent and allowing 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.

[2]
Next, the processed product in the pressure vessel is filtered. Then, the filtrate is removed, and the solvent-insoluble matter separated by filtration is recovered. And the collect | recovered solvent insoluble content is immersed in the solvent in which lignin is soluble (immersion process).

  As the solvent in which lignin is soluble, for example, those containing alcohols such as methanol and ethanol, and ketones such as acetone and methyl ethyl ketone are preferably used.

  The immersion time is not particularly limited, but is preferably about 1 to 48 hours, and more preferably about 2 to 30 hours.

[3]
Next, a solvent soluble part is collect | recovered from the processed material obtained by the immersion process. And the solvent in which lignin is soluble is distilled off from the collect | recovered solvent soluble part (distillation process). Thereby, the lignin derivative of the present invention is obtained.

[4]
The lignin secondary derivative of the present invention includes a reactive group introduction step of introducing a reactive group into the lignin derivative by mixing the treated biomass and a compound containing a reactive group after the distillation step. Manufactured by doing.

  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, a chloro 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.

  As described above, the lignin derivative and the lignin secondary derivative of the present invention can be produced.

<Lignin resin composition>
Next, the lignin resin composition of the present invention will be described.

  As described above, the lignin resin composition of the present invention 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 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. A well-known crosslinking agent can be mentioned with normal phenol resins, such as resin. 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 of the present invention, 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 components, the lignin resin composition of the present invention may contain, if necessary, an alkali metal salt such as sodium methoxy, t-butoxy potassium, an alkaline earth metal salt such as calcium acetate, Na ₂ O. , An accelerator such as an alkali metal oxide such as K ₃ 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 / amines, synthetic waxes such as hydrogenated oil, paraffin wax, montan wax, stearic acid, etc. Natural waxes, higher fatty acids such as stearic acid and zinc stearate and their metal salts, release agents such as paraffin, silicone oil, low stress components such as silicone rubber, antimony trioxide, hydroxylation Examples thereof include flame retardants such as luminium, magnesium hydroxide, zinc borate, zinc molybdate, phosphazene, inorganic ion exchangers such as bismuth oxide hydrate, and one or more of these are combined. Things are used.

  Further, when the lignin resin composition of the present invention 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. 0.1 to 5 parts by weight is more preferable. 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. (Crosslinking agent mixing step). 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.

  Moreover, when obtaining the molded object by shape | molding the lignin resin composition of this invention, it is preferable to prepare the molding material which added the filler to the lignin resin composition, and to shape | mold 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 of the present invention will be described.

The prepreg of the present invention 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 target performance of the prepreg, the thickness of the insulating layer in the substrate (composite structure) 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 (the composite structure of the present invention) 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 be formed into an arbitrary shape by a mold at the time of molding, and the obtained resin plate is an electric / electronic material such as a printed circuit board, a structural material, a building material, an insulating material. Etc. are preferably used.

  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, an arbitrary component may be added to the prepreg or the resin plate.

Next, specific examples of the present invention will be described.
1. Manufacture of laminated board (resin board) (Sample No. 1)
<Production of lignin derivative>
15 g of Soso bamboo powder (60 mesh under) and 120 g of pure water were introduced into a 300 ml autoclave, and the contents were treated at 4 MPa and 150 ° C. for 30 minutes with stirring at 500 rpm to decompose the Soso bamboo powder. The pressure was adjusted by pressurizing by blowing argon gas. Subsequently, 10.0 g of water-insoluble parts were separated by filtering the decomposition product and washing with pure water. The water-insoluble part was immersed in 200 ml of acetone overnight and filtered to recover the acetone-soluble part. Subsequently, 2.7 g of lignin derivative was obtained by evaporating acetone from the acetone soluble part and then drying.

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 5 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 20. That is, the integrated value of the plurality of peaks attributed to the aromatic proton was 5% of the integrated value of the plurality of peaks attributed to the aliphatic proton.

  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) = 2200 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>
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 laminate>
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 No. 2)
Except for changing the type of biomass and the temperature and pressure 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.

Sample No. For ¹ lignin derivative, the spectrum of chemical shift 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 was shown in Table 1. It was shown to.

  Furthermore, sample no. The number average molecular weight (Mn) of the 2 lignin derivatives was measured and shown in Table 1.

(Sample No. 3)
Introduce 15 g of cedar flour (60 mesh under) and 120 g of pure water into a 300 ml autoclave, stir the contents at 500 rpm, and stir at room temperature for 15 minutes as a pretreatment to fully blend cedar flour and pure water. Then, the cedar flour was decomposed by treatment at 6 MPa and 240 ° C. for 60 minutes. The pressure was adjusted by pressurization by blowing argon gas. Subsequently, 10.0 g of water-insoluble parts were separated by filtering the decomposition product and washing with pure water. The water-insoluble part was immersed in 200 ml of acetone overnight and filtered to recover the acetone-soluble part. Subsequently, 2.7 g of lignin derivative was obtained by evaporating acetone from the acetone soluble part and then drying.

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 5 ppm.

  Therefore, for each detected peak, the ratio of the integrated value of the plurality of peaks attributed to the aromatic protons to the integrated value of the plurality of peaks attributed to the aliphatic protons is shown in Table 1.

  Sample No. The number average molecular weight (Mn) of the 3 lignin derivatives was measured and shown in Table 1.

Hereinafter, sample no. A laminate was obtained in the same manner as in 1.
(Sample Nos. 4-9)
Except for changing the type of biomass and the temperature and pressure in the decomposition treatment as shown in Table 1, sample No. A lignin derivative was obtained in the same manner as in Example 3, 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 Nos. 10 and 11)
Except for changing the type of biomass and the temperature and pressure 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. 12)
<Production of lignin derivative>
Take 10 g of Somune bamboo powder in a 500 ml beaker, add acetone solution of p-cresol (including 3 mol times phenol derivative per lignin constituent unit), stir with a glass rod, and let stand for 24 hours. Thereafter, acetone was completely distilled off to obtain p-cresol sorbed bamboo powder. To this bamboo flour, 100 ml of 72% by weight 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, deoxidized, 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 1.
Further, the number average molecular weight (Mn) of the obtained lignin derivative was measured and shown in Table 1.

<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 laminate>
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. 13)
Except that a lignin secondary derivative was produced by introducing an epoxy group into the lignin derivative according to the following steps, 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, 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 varnish and 2 mass parts of 2-methylimidazole were mixed, and the resin varnish for base material impregnation was obtained.

<Manufacture of prepreg and laminate>
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 Nos. 14 to 23)
Except for changing the type of lignin derivative and the type of reactive group to be introduced as shown in Table 2, sample No. In the same manner as in No. 13, a lignin secondary derivative was obtained and a laminate was obtained.

  In addition, 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.

(Sample No. 24)
<Production of secondary lignin derivative>
Sample No. Twelve lignin derivatives were epoxidized by the following method.

First, sample No. 1 was placed in a 100 ml three-necked flask equipped with a stirrer, a cooler and a dropping funnel. While introducing 1.4 g of 12 lignin derivatives and 100 g of epichlorohydrin and refluxing under reduced pressure under a pressure of 100 mmHg (1.3 × 10 ⁴ Pa), 1 g of an aqueous sodium hydroxide solution having a concentration of 20% by mass was added. It was added dropwise over 30 minutes. 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 1.3g 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 a lignin secondary derivative varnish having a resin content of 50% by mass.

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

<Manufacture of prepreg and laminate>
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. However, the laminated board could not be formed due to insufficient melting.

2. Evaluation of laminate 2.1. Evaluation of substrate impregnation property 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

2.2. 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 the time of bending fracture is 1% or more. X: Elongation at the time of bending fracture is less than 1%.

  First, as apparent from Tables 1 and 2, sample No. 3 to 9 and 15 to 21 correspond to examples (present invention), and sample Nos. 1, 2, 10-14 and 22-24 correspond to comparative examples.

  And it was recognized that the laminated board corresponded to each Example has the high base material impregnation property, ie, the uniformity of the resin varnish with respect to a kraft paper, and is excellent in the elongation at the time of bending fracture. This is because each sample No. used in the production of the laminated plate was obtained. This is considered to be because the reactivity and meltability or solubility of the lignin derivative is optimized because the aromatic proton content of the lignin derivative is within a predetermined range.

  On the other hand, the laminated plate corresponding to each comparative example includes those having poor base material impregnation properties, those having poor elongation at bending fracture (brittle), and those that could not be molded. It was.

Claims (8)

Manufactured by decomposing the biomass at a temperature of 200 to 380 ° C., a time of 480 minutes or less, and a pressure of 4 to 22 MPa after pretreatment of stirring the biomass and solvent at a temperature of 0 to 150 ° C. for a time of 1 to 120 minutes. And
When subjected to of ^{1 H-NMR} analysis, the integral value of the peak attributable to the aromatic protons in the resulting spectrum, characterized in that 15 to 50% of the integrated value of the peak attributable to aliphatic protons lignin Derivative.   The lignin derivative according to claim 1, wherein at least one of the ortho-position and the para-position of the aromatic ring is unsubstituted with respect to the hydroxyl group.   The lignin derivative according to claim 1 or 2, wherein the lignin derivative has a polystyrene-equivalent number average molecular weight of 200 to 2,000 as measured by gel permeation chromatography.   A lignin secondary derivative obtained by introducing a reactive group into the lignin derivative according to any one of claims 1 to 3.   The lignin secondary derivative according to claim 4, wherein the reactive group is an epoxy group.   A lignin resin composition comprising at least one of the lignin derivative according to any one of claims 1 to 3 and the lignin secondary derivative according to claim 4 or 5, and a crosslinking agent.   A prepreg obtained by impregnating a base material with the lignin resin composition according to claim 6.   A composite structure obtained by curing the prepreg according to claim 7.