Glycol lignin and resin composition

Abstract

To provide a glycol lignin exhibiting high compatibility with low-polarity substances.SOLUTION: A glycol lignin has, in its molecular structure, at least one group selected from -O-C(=O)-R1, -O-Si(R2)3, and -O-((CH2)n-O)m-R3, wherein the total number of the groups -O-C(=O)-R1, -O-Si(R2)3, and -O-((CH2)n-O)m-R3 is 2.5 mmol / g or more and 10.0 mmol / g or less. (Here, R1 represents an alkyl group, R2 represents an alkyl group, and R3 represents an alkyl group; the three R2 groups may be the same or different. n represents a number of 1 or more and 10 or less, and m represents a number of 10 or more and 2000 or less).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to glycol lignin and resin compositions. [Background technology]

[0002] 2. Description of the Related Art As modified lignin obtained by modifying lignin extracted from wood or the like with an alcohol compound such as polyalkylene glycol, the use of glycol lignin for various applications has been investigated.

[0003] For example, Patent Document 1 discloses a process for producing lignocellulose, comprising: (a) a process for solvolyzing lignocellulose with at least one glycol-based digestion solvent selected from polyethylene glycol, diethylene glycol, ethylene glycol, propylene glycol, polypropylene glycol, glycerin, and polyglycerin in the presence of an acid catalyst under normal pressure; (b) a process for mixing the reaction mixture obtained after the solvolysis process with a dilute alkali, and then separating a solution fraction containing glycol lignin from a solid content; and (c) a process for isolating the solution fraction with sulfuric acid to produce glycol lignin. (d) obtaining glycol lignin as a precipitate from the solution fraction acidified with sulfuric acid; (e) collecting the supernatant liquid after separation of the glycol lignin precipitate and neutralizing the collected solution by adding sodium hydroxide to the collected solution; (f) concentrating the neutralized solution to a moisture content of 10% or less by heating to recover the cooking solvent; and (g) separating the sodium sulfate crystals produced by the concentration. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-197517 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, glycol lignin, which is lignin modified with an alcohol compound, has a large number of hydroxyl groups (-OH) in its molecular structure, making it highly polar. Because of its high polarity, it has low compatibility with low-polarity substances such as low-polarity resins and low-polarity solvents. Therefore, there is a demand for glycol lignin that can be mixed well with low-polarity substances.

[0006] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a glycol lignin that exhibits high compatibility with low-polarity substances, and a resin composition containing the glycol lignin. [Means for solving the problem]

[0007] Means for solving the above problems include the following means. <1> In the molecular structure, -OC(=O)-R 1 , -O-Si(R 2 )3, and -O-((CH2) n -O) m -R 3 and having at least one group selected from The above-mentioned -OC(=O)-R 1 , the -O-Si(R 2 )3, and the -O-((CH2) n -O) m -R 3 A glycol lignin having a total number of groups of 2.5 mmol / g or more and 10.0 mmol / g or less. (Note that the above R 1 R 2 R 3 represents an alkyl group, and the three R 2 may be the same or different. The n represents 1 or more and 10 or less, and the m represents 10 or more and 2000 or less. <2> In the molecular structure, the number of -OH groups directly bonded to aromatic groups is 1.0 mmol / g or more. <1> The glycol lignin according to claim 1. <3> <1> or <2> A resin composition comprising the glycol lignin according to claim 1 and a resin. Effect of the Invention

[0008] According to the present disclosure, there is provided a glycol lignin that exhibits high compatibility with low-polarity substances, and a resin composition containing the glycol lignin. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment that is an example of the present disclosure will be described. These descriptions and examples are merely illustrative of the embodiment, and are not intended to limit the scope of the invention. In the present specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the present specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples.

[0010] Each component may contain multiple types of the corresponding substance. When referring to the amount of each component in a composition, if the composition contains multiple substances corresponding to each component, the amount refers to the total amount of those multiple substances present in the composition, unless otherwise specified. The term "process" includes not only independent processes, but also processes that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved.

[0011] <Specific glycol lignin> The glycol lignin according to the embodiment of the present disclosure (also referred to as “specific glycol lignin” in the present disclosure) has a molecular structure in which —O—C(═O)—R 1 , -O-Si(R 2 )3, and -O-((CH2) n -O) m -R 3and may have -OH. And, -OC(=O)-R 1 , -O-Si(R 2 )3, and -O-((CH2) n -O) m -R 3 The total number of groups (referred to as the "functional number" in this disclosure) is 2.5 mmol / g or more and 7.0 mmol / g or less. (Note: R 1 represents an alkyl group, R 2 represents an alkyl group, R 3 represents an alkyl group, and there are three R 2 may be the same or different. n is 1 or more and 10 or less, and m is 10 or more and 2000 or less.)

[0012] The glycol lignin (specific glycol lignin) according to the embodiment of the present disclosure has high compatibility with low-polarity substances such as low-polarity resins and low-polarity solvents. The reason for this is presumed to be as follows.

[0013] Modified lignin (referred to as "glycol lignin" in this disclosure) modified with an alcohol compound such as polyalkylene glycol has many hydroxyl groups (-OH) in its molecular structure. As a result, glycol lignin has the property of being highly polar due to the large number of hydroxyl groups, and has low compatibility with low-polarity substances such as low-polarity resins such as polyethylene and polypropylene, and low-polarity solvents. When glycol lignin is mixed with or dissolved in such low-polarity substances, a compatibilizer or the like is used. Therefore, there is a demand for glycol lignin that can be well mixed or dissolved in low-polarity substances without the use of a compatibilizer or the like.

[0014] In contrast, the glycol lignin (specific glycol lignin) according to an embodiment of the present disclosure has a structure represented by the formula: -OC(=O)-R 1 , -O-Si(R 2 )3, and -O-((CH2) n -O) m -R 3In other words, in the specific glycol lignin, at least a part of the hydroxyl groups (-OH) is -OC(=O)-R 1 , -O-Si(R 2 )3, and -O-((CH2) n -O) m -R 3 The number of -OH groups is reduced by either of the following: As a result, the specific glycol lignin has a low polarity and exhibits high compatibility with substances with low polarity.

[0015] Glycol lignin also has the property of having high adhesion to metals due to the large number of hydroxyl groups. Here, when producing a resin composition containing glycol lignin and a resin, for example, a method is performed in which the two are kneaded on a heated metal kneading member (for example, a metal roll). However, glycol lignin may adhere strongly to the metal kneading member, and as a result, kneading with the resin may not be performed properly, and cleaning of the kneading member may be required after the kneading operation. Therefore, glycol lignin with reduced adhesion to metals is required. In contrast, the specific glycol lignin has a reduced number of hydroxyl groups (-OH) and has reduced adhesion to metals, which prevents the specific glycol lignin from sticking to the metal kneading members, allowing proper kneading with resins using the metal kneading members, and eliminating or reducing the need to clean the kneading members after the kneading operation.

[0016] The glycol lignin (specific glycol lignin) according to the embodiment of the present disclosure has a molecular structure including -OC(=O)-R 1 , -O-Si(R 2 )3, and -O-((CH2) n -O) m -R 3 and may have -OH.

[0017] (Regarding general glycol lignin) First, a general glycol lignin will be described. Glycol lignin refers to a compound in which at least a portion of lignin is substituted with a residue obtained by removing at least one hydroxyl group from an alcohol compound (an alcohol having two or more hydroxyl groups in one molecule) described below. In other words, glycol lignin is a compound derivatized with an alcohol compound described below.

[0018] For example, a compound in which at least a portion of lignin is substituted with polyethylene glycol, which is a type of alcohol compound, has the following molecular structure, for example.

[0019] [ka]

[0020] Here, the alcohol compound includes an alcohol having two or more hydroxyl groups in one molecule. The alcohol compound is preferably an alcohol having 2 to 3 hydroxyl groups in one molecule, and more preferably an alcohol having 2 hydroxyl groups in one molecule.

[0021] Examples of alcohols having two hydroxyl groups in one molecule include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol; polyalkylene glycol; polyglycerin; and the like. Examples of alcohols having three hydroxyl groups in one molecule include glycerin; and compounds obtained by addition polymerization of alkylene oxide to glycerin. Moreover, as the alcohol compound, for example, polyglycerin may be used.

[0022] As the alcohol compound, it is preferable to use at least one selected from the group consisting of polyethylene glycol, glycerin, and polyglycerin. That is, the glycol lignin is preferably a glycol lignin derivatized with at least one selected from the group consisting of polyethylene glycol, glycerin, and polyglycerin.

[0023] Glycol lignin can be obtained, for example, by solvolyzing lignocellulose in the presence of a catalyst using an alcohol compound as a solvent, and then separating glycol lignin from the resulting reaction solution. An example of a method for producing glycol lignin is the method described in JP 2017-197517 A.

[0024] As described above, glycol lignin is a compound in which at least a portion of lignin is substituted with a residue obtained by removing at least one hydroxyl group from the alcohol compound (an alcohol having two or more hydroxyl groups in one molecule). Therefore, glycol lignin has many hydroxyl groups (-OH) in its molecular structure.

[0025] (Hydrophobization of hydroxyl groups) The glycol lignin (specific glycol lignin) according to the embodiment of the present disclosure has a molecular structure including -OC(=O)-R 1 , -O-Si(R 2 )3, and -O-((CH2) n -O) m -R 3 has at least one group selected from In addition, the above R 1 R 2 R 3 represents an alkyl group, and the three R 2 may be the same or different. The n represents 1 or more and 10 or less (n is preferably 1 or more and 4 or less, more preferably 2 or more and 3 or less, and further preferably 2), and the m represents 10 or more and 2000 or less (m is preferably 10 or more and 1000 or less).

[0026] (1)-OC(=O)-R 1 -OC(=O)-R1 In the group (hereinafter also referred to as "group (1)"), R 1 is an alkyl group. 1 The alkyl group represented by the formula (I) is preferably a linear, branched or cyclic alkyl group having from 1 to 10 carbon atoms. The number of carbon atoms is more preferably from 1 to 6, and even more preferably from 1 to 3. The alkyl group is more preferably linear or branched, and even more preferably linear.

[0027] Examples of compounds for introducing group (1) into glycol lignin (hereinafter referred to as "hydrophobizing agent (1)") include acetic anhydride (CH3-C(=O)-OC(=O)-CH3), propionic anhydride (C2H5-C(=O)-OC(=O)-C2H5), butyric anhydride (C3H7-C(=O)-OC(=O)-C3H7), valeric anhydride (C4H9-C(=O)-OC(=O)-C4H9), isovaleric anhydride ((i)C4H9-C(=O)-OC(=O)-(i)C4H9), carboxylic anhydrides such as acrylic anhydride, methacrylic anhydride, benzoic anhydride, and 4-methylbenzoic anhydride, and carboxylic acids such as acetic acid, acrylic acid, methacrylic acid, benzoic acid, and 4-methylbenzoic acid. Among these, acetic anhydride, methacrylic anhydride, acetic acid, and methacrylic acid are preferred, and acetic anhydride and methacrylic anhydride are more preferred.

[0028] When introducing the group (1) into glycol lignin, glycol lignin is mixed with a hydrophobizing agent (1) (e.g., acetic anhydride) and the reaction temperature is adjusted (e.g., from room temperature (e.g., 20°C) to 100°C) to react. This converts the hydroxyl groups in glycol lignin into the groups (1) (-OC(=O)-R 1 By controlling the reaction conditions, the ratio of hydroxyl groups in glycol lignin replaced with group (1) can be adjusted, and it is also possible to replace all (100%) of the hydroxyl groups.

[0029] However, when providing antioxidant properties to the specific glycol lignin, it is preferable that the molecular structure of the specific glycol lignin has many aromatic hydroxyl groups (i.e., -OH groups directly bonded to aromatic groups). Therefore, it is preferable to preferentially replace aliphatic hydroxyl groups (i.e., -OH groups directly bonded to aliphatic groups) with group (1) by controlling the reaction conditions. When preferentially replacing aliphatic hydroxyl groups with group (1), it is preferable to set the reaction conditions to a temperature of 70°C or less and a reaction time of 3 hours or less. In addition, when using a hydrophobizing agent (1) having an unsaturated aliphatic compound such as acrylic acid, it is preferable to set the reaction conditions to a temperature of 40°C or less and a reaction time of 24 hours or less in order to suppress the occurrence of radical polymerization during synthesis.

[0030] (2)-O-Si(R 2 )3 -O-Si(R 2 In the group (hereinafter also referred to as “group (2)”), R 2 is an alkyl group. 2 The alkyl group represented by the formula (2) is preferably a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms. 2 may be the same or different. The number of carbon atoms is more preferably 1 to 6, and even more preferably 1 to 3. The alkyl group is more preferably linear or branched, and even more preferably linear.

[0031] Examples of compounds for introducing group (2) into glycol lignin (hereinafter referred to as "hydrophobizing agent (2)") include silylation reagents such as hexamethyldisilazane ((CH3)3-Si-NH-Si-(CH3)3), hexaethyldisilazane ((C2H5)3-Si-NH-Si-(C2H5)3), hexapropyldisilazane ((C3H7)3-Si-NH-Si-(C3H7)3), N-methyl-N-trimethylsilylfluoroacetamide, N,O-bis(trimethylsilyl)trifluoroacetamide, trimethylsilylimidazole, N-trifluoroacetylimidazole, and chlorotrimethylsilane. Among these, hexamethyldisilazane is preferably used.

[0032] When introducing the group (2) into glycol lignin, glycol lignin is mixed with a hydrophobizing agent (2) (e.g., hexamethyldisilazane) and the reaction temperature is adjusted (e.g., at room temperature (e.g., 20°C or higher) to 40°C or lower) to react. This converts the hydroxyl groups in the glycol lignin into the groups (2) (-O-Si(R 2 By controlling the reaction conditions, the ratio of hydroxyl groups in glycol lignin replaced with group (2) can be adjusted, and it is also possible to replace all (100%) of the hydroxyl groups.

[0033] The specific glycol lignin having the group (2) has better compatibility with non-polar substances such as non-polar resins and non-polar solvents than the specific glycol lignin having only the groups (1) and (3) and not the group (2).

[0034] In addition, since the specific glycol lignin having the group (2) is hydrolyzed by heating, the group (2) can be converted back to a hydroxyl group by heating. Therefore, when it is desired to increase the antioxidant properties of the specific glycol lignin, it is possible to heat the lignin (for example, at 120°C or higher and 250°C or lower) to convert the group (2) to a hydroxyl group and increase the number of aromatic hydroxyl groups in the molecular structure.

[0035] (3)-O-((CH2) n -O) m -R 3 -O-((CH2) n -O) m -R 3 In the group (hereinafter also referred to as "group (3)"), R 3 is an alkyl group. 3 The alkyl group represented by the formula (I) is preferably a linear, branched or cyclic alkyl group having from 1 to 10 carbon atoms. The number of carbon atoms is more preferably from 1 to 6, and even more preferably from 1 to 3. The alkyl group is more preferably linear or branched, and even more preferably linear.

[0036] As a method for introducing the group (3) into glycol lignin, for example, when lignin is derivatized with an alcohol compound to synthesize glycol lignin, the alcohol compound is not a polyalkylene glycol having hydroxyl groups at both ends, but an alkoxy group (-OR 3 )-modified polyalkylene glycol (HO-((CH2) n -O) m -R 3 ), or polyalkylene glycol with one terminal ester (HO-((CH2) n -O) m -C(=O)-R 3 ) is used.

[0037] One end is alkoxy (-OR 3 ) or esterification (-OC(=O)-R 3 Examples of methoxylated polyalkylene glycols include methoxylated polyalkylene glycols (HO-((CH2) n -O) m -CH3), ethoxylated polyalkylene glycol (HO-((CH2) n -O) m -C2H5), propoxylated polyalkylene glycol (HO-((CH2) n -O) m --C3H7), polyethylene glycol monooleate, polyethylene glycol monostearate, polyethylene glycol monolaurate, etc. In addition, polyalkylene glycol (HO-((CH2) n -O) m -R 3 or HO-((CH2) n -O) m -C(=O)-R 3 The number of n in the above formula (1) is 1 to 10, preferably 1 (methylene) to 4 (butylene), more preferably 2 (ethylene) to 3 (propylene), and further preferably 2 (ethylene). m is 10 to 2000, preferably 10 to 1000. Among these, as the polyalkylene glycol having one terminal alkoxylated or esterified, methoxylated polyethylene glycol is preferred.

[0038] (Number of functional groups) Specific glycol lignin is -OC(=O)-R 1 , -O-Si(R 2 )3, and -O-((CH2) n -O) m -R 3 The total number (number of functional groups) is 2.5 mmol / g or more and 10.0 mmol / g or less.

[0039] By having the number of functional groups of 2.5 mmol / g or more, the number of -OH in the molecular structure is reduced, and high compatibility with substances with low polarity is obtained. In addition, by having the number of functional groups of 2.5 mmol / g or more, the specific glycol lignin is prevented from sticking to metal kneading members. On the other hand, the upper limit of the number of functional groups is set to 10.0 mmol / g or less from the viewpoint of ease of introduction of functional groups into glycol lignin. The number of functional groups is from 2.5 to 10.0 mmol / g, preferably from 3.0 to 8.5 mmol / g, and more preferably from 4.0 to 7.0 mmol / g.

[0040] The number of functional groups (mmol / g) in the molecular structure of a particular glycol lignin, i.e. -OC(=O)-R1 , -O-Si(R 2 )3, and -O-((CH2) n -O) m -R 3 The total number of groups is 1 It can be calculated as the number per gram using H-NMR.

[0041] (aromatic hydroxyl group) The specific glycol lignin preferably has a molecular structure in which the number of -OH groups directly bonded to aromatic groups (referred to as "aromatic hydroxyl groups" in the present disclosure) is 1.0 mmol / g or more. When the number of aromatic hydroxyl groups is within the above range, the antioxidant properties of the specific glycol lignin can be enhanced. The number of aromatic hydroxyl groups is more preferably 2.0 mmol / g or more, and further preferably 3.0 mmol / g or more.

[0042] On the other hand, the upper limit of the number of aromatic hydroxyl groups is not particularly limited, but from the viewpoint of the decomposition limit due to solvolysis, it is preferably 10 mmol / g or less, and more preferably 5 mmol / g or less.

[0043] Here, the aromatic hydroxyl group refers to a hydroxyl group directly bonded to an aromatic ring in the molecular structure of the specific glycol lignin, for example, a hydroxyl group directly bonded to a phenol skeleton, whereas the -OH directly bonded to an aliphatic group (referred to as an "aliphatic hydroxyl group" in this disclosure) refers to a hydroxyl group directly bonded to an aliphatic group in the molecular structure of the specific glycol lignin, for example, a hydroxyl group directly bonded to an alkyl group.

[0044] The number of -OH (aromatic hydroxyl groups) directly bonded to aromatic groups and the number of -OH (aliphatic hydroxyl groups) directly bonded to aliphatic groups in the molecular structure of a specific glycol lignin can be determined by the following method. Pyridine and acetic anhydride, 15 times the mass ratio of the glycol lignin to be measured, are placed in a recovery flask, and the glycol lignin is dissolved by stirring. A reflux tube is then connected, and the mixture is reacted for 6 hours in a 60°C oil bath while stirring with a stirrer to acetylate the hydroxyl groups in the glycol lignin. The liquid after the reaction is precipitated in purified water, filtered, and the residue is dissolved in 10 times the mass of tetrahydrofuran (THF), precipitated again in purified water, and filtered. Next, the residue after filtration is washed in purified water to completely remove the pyridine odor and acetic acid odor, and then completely dried in a vacuum dryer at 50°C and -0.9 MPa. The product is subjected to two-dimensional NMR (nuclear magnetic resonance) measurement using deuterated dimethyl sulfoxide (DMSO) and pentafluorobenzaldehyde as an internal standard substance to determine the number of aromatic acetyl groups and the number of aliphatic acetyl groups. The number of aromatic acetyl groups and the number of aliphatic acetyl groups can be taken as the number of aromatic hydroxyl groups and the number of aliphatic hydroxyl groups, respectively.

[0045] The number average molecular weight of the specific glycol lignin is, for example, preferably 300 or more and 100,000 or less, more preferably 500 or more and 70,000 or less, and even more preferably 1,000 or more and 50,000 or less.

[0046] The number average molecular weight of the specific glycol lignin is a value measured by gel permeation chromatography (GPC) under the following measurement conditions. ·Column:TSKgel SuperAWM-H x2 (6.0mm ID x 15cm x 2) Column temperature: 40℃ Eluent: 50mM LiBr + 100mM phosphate DMF ·Flow rate: 0.6mL / min Detector: RI (Differential Refractive Index Detector)

[0047] (Application) The specific glycol lignin can be used as an additive to resins, rubbers, solvents, and the like.

[0048] <Resin composition> The resin composition according to an embodiment of the present disclosure contains the specific glycol lignin and a resin.

[0049] The content of the specific glycol lignin relative to the mass of the entire resin composition is not particularly limited, but is preferably 5 mass% or more, preferably 5 mass% or more and 80 mass% or less, more preferably 5 mass% or more and 50 mass% or less, and even more preferably 5 mass% or more and 40 mass% or less.

[0050] (resin) The resin composition according to an embodiment of the present disclosure contains a resin. The resin is not particularly limited, and thermoplastic resin and thermosetting resin are applicable. Fiber reinforced plastic (FRP) is also applicable. Thermoplastic resin is a resin that softens and becomes plastic when heated, and hardens when cooled to room temperature (25°C). A thermosetting resin is a resin that hardens when heated. Fiber-reinforced plastic (FRP) refers to plastic in which fibers have been added to the resin, for example, to improve strength.

[0051] Examples of thermoplastic resins include polyolefin resins, polyether resins, polyvinyl resins, fluororesins, ABS resins (acrylonitrile-butadiene-styrene copolymer resins), AS resins (acrylonitrile-styrene copolymer resins), (meth)acrylic resins, and thermoplastic epoxy resins.

[0052] A polyolefin resin is a resin that contains 50 mass % or more of structural units derived from olefins (excluding vinyl compounds) based on the total structural units contained in the entire resin. Examples of polyolefin resins include ethylene-propylene copolymers such as polyethylene (PE), polypropylene (PP), poly-1-butene, poly-4-methyl-1-pentene, and ethylene propylene rubber (EPR); ethylene-propylene-butene copolymers; ethylene-butene copolymers; ethylene-vinyl alcohol copolymers; and ethylene-ethyl acrylate copolymers.

[0053] A polyether resin is a polymer having continuous ether bonds in the main chain. Examples of the polyether resin include polyacetal, polyoxytetramethylene glycol, polyoxypropylene glycol, polyoxyethylene glycol, polyoxytetramethylene glycol phenyl ether, polyoxypropylene glycol phenyl ether, polyoxyethylene glycol phenyl ether, polyoxytetramethylene glycol butyl ether, polyoxypropylene glycol butyl ether, and polyoxyethylene glycol butyl ether.

[0054] A polyvinyl resin is a resin that contains 50% by mass or more of structural units derived from vinyl compounds relative to the total structural units contained in the entire resin. Examples of the polyvinyl resin include polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol, and polyvinyl butyral.

[0055] A fluororesin is a resin that contains fluorine atom-containing structural units in an amount of 50 mass % or more relative to the total structural units contained in the entire resin. Examples of fluororesins include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF).

[0056] The (meth)acrylic resin is a resin that contains monomer units derived from (meth)acrylic acid or a (meth)acrylic acid ester compound in an amount of 50 mass % or more relative to all of the structural units contained in the entire resin. Examples of the (meth)acrylic resin include polyacrylic acid, polyacrylic acid esters, polymethacrylic acid, polymethacrylic acid esters, polyacrylamide, and polyacrylonitrile.

[0057] A thermoplastic epoxy resin is a thermoplastic resin that has a structural unit having an oxirane ring (epoxy group). Examples of thermoplastic epoxy resins include bisphenol A type epoxy resins, bisphenol fluorene type epoxy resins, cresol novolac type epoxy resins, phenol novolac type epoxy resins, cyclic aliphatic type epoxy resins, long-chain aliphatic type epoxy resins, glycidyl ester type epoxy resins, and glycidyl amine type epoxy resins.

[0058] Examples of the thermosetting resin include phenol resin, melamine resin, urea resin, and polyurethane resin.

[0059] The phenolic resin is obtained by reacting formaldehyde with a phenol in the presence of an acid catalyst or an alkali catalyst. Examples of the phenol resin include novolac type phenol resin, resol type phenol resin, and biphenyl type phenol resin.

[0060] A polyurethane resin is a resin that contains 50 mass % or more of structural units having a urethane bond (-NHCOO-) relative to the total structural units contained in the entire resin. The polyurethane resin may be a compound obtained by reacting a known polyisocyanate with a known polyol. Examples of the polyisocyanate include 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, toluene diisocyanate, and naphthalene diisocyanate. Examples of the polyol include ethylene glycol, propylene glycol, 1,4-butanediol, and polyalkylene glycol.

[0061] Fiber-reinforced plastic (FRP) is a plastic in which fibers have been added to the resin for the purpose of improving strength, etc. The resin (matrix resin) contained in the fiber reinforced plastic is not particularly limited, and either a thermoplastic resin or a thermosetting resin can be used. Examples of the matrix resin include resins selected from thermoplastic epoxy resins, phenoxy resins, polyolefins and their acid-modified products, polypropylene, polystyrene, polymethyl methacrylate, AS resins, ABS resins, thermoplastic aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonates, polyimides, polyamides, polyamideimides, polyetherimides, polyethersulfones, polyphenylene ethers and their modified products, polyphenylene sulfide, polyoxymethylene, polyarylates, polyether ketones, polyether ether ketones, polyether ketone ketones, unsaturated polyester resins, phenolic resins, urethane resins, and nylons. Among these, thermoplastic epoxy resins are preferred as the matrix resin.

[0062] Examples of the fibers contained in the fiber-reinforced plastic include fibers selected from glass fibers, carbon fibers (e.g., pitch-based carbon fibers and PAN-based carbon fibers), cellulose nanofibers, aramid fibers, nylon fibers, polyester fibers, rayon fibers, hemp fibers, organic fibers, chemical fibers, synthetic resin fibers, and natural fibers. These fibers can be used alone or in combination. Among them, glass fibers are preferred as the fibers.

[0063] From the viewpoint of compatibility with resins, the resin contained in the resin composition may be a low polar resin. For this reason, examples of the resin include polyolefin resins (e.g., polyethylene (PE), polypropylene (PP), etc.), polystyrene (PS), acrylonitrile-styrene resins (AS), acrylonitrile-butadiene-styrene resins (ABS), polyvinyl chloride (PVC), methacrylic resins (PMMA), polyethylene terephthalate (PET), polyvinyl alcohol (PVA), polyamide (PA), polyacetal (POM), polycarbonate (PC), modified polyphenylene ether (m-PPE), polybutylene terephthalate (PBT), glass, etc. Preferred are glass fiber (GF) reinforced polyethylene terephthalate (GF-PET), ultra-high molecular weight polyethylene (UHPE), polylactic acid (PLA), polybutylene succinate (PBS), polycaprolactone (PCL), polyglycolic acid (PGA), polyhydroxyalkanoic acid (PHA), phenolic resin (PF), urea resin (UF), melamine resin (MF), unsaturated polyester resin (UP), polyurethane (PU), diallyl phthalate resin (PDAP), allyl resin, silicone resin (SI), alkyd resin, epoxy resin (EP), furan resin, and the like.

[0064] The resin content is preferably 20% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 95% by mass or less, and even more preferably 60% by mass or more and 95% by mass or less, based on the mass of the entire resin composition.

[0065] (Other Ingredients) The resin composition according to the embodiment of the present disclosure may contain other components other than the specific glycol lignin and the resin as long as the effects of the present disclosure are not significantly impaired. The other components are not particularly limited, and include additives that are generally used as additives for resins. Specific examples of the other components include antioxidants, flame retardants, fillers, colorants, plasticizers, and solvents.

[0066] (Method of producing resin composition) Examples of a method for producing a resin composition according to an embodiment of the present disclosure include a method of melt-kneading a specific glycol lignin, a resin, and, if necessary, other components. Apparatuses that are preferably used for melt-kneading include, for example, an extruder, a roll, a kneader, a Banbury mixer, etc., and a kneading method using a metal roll (kneading roll) is preferred.

[0067] (Applications of resin composition) The use of the resin composition according to the embodiment of the present disclosure is not particularly limited, and examples thereof include resin parts contained in various articles such as daily necessities, building materials, furniture, outdoor goods, storage containers, and electrical appliances. Examples of household items include tableware, cutlery, toys, etc. Building materials include floors, walls, ceilings, stairs, handrails, doors, and coatings used thereon. The furniture includes desks, chairs, cabinets, etc. Outdoor equipment includes tents, folding tables, folding chairs, etc. Examples of storage containers include Tupperware. Electrical appliances include televisions, computers, speakers, refrigerators, vacuum cleaners, etc. EXAMPLES

[0068] Hereinafter, the present disclosure will be described based on examples, but the present disclosure is not limited to these examples. In the following description, unless otherwise specified, all "parts" and "%" are based on mass.

[0069] <Example 1> [1] Acetylation of glycol lignin Glycol lignin (Lignotop SD4, manufactured by Lignomateria Co., Ltd.), pyridine, and acetic anhydride were placed in a 100 mL eggplant flask in the composition shown in Table 1, and the mixture was reacted at 60°C for 3 hours with stirring. After the reaction was completed, the reaction solution was added in small portions to 1 L of clean water to cause reprecipitation. The precipitate was collected by suction filtration and then dried under reduced pressure to obtain a powder of specific glycol lignin (1).

[0070] Infrared absorption spectroscopy (IR) was obtained for glycol lignin and specific glycol lignin (1). -1 The OH stretching vibration of the hydroxyl group was observed at 3400 cm for specific glycol lignin (1). -1 The disappearance of the absorption at 1740cm -1 The absorption due to the C=O stretching of the carbonyl group was confirmed. This suggests that the hydroxyl groups of glycol lignin are acetylated.

[0071] Next, for quantitative evaluation of hydroxyl groups, 14.3 mg of specific glycol lignin (1) and 11.5 mg of pentafluorobenzaldehyde (196.08 g / mol) as an internal standard were dissolved in a deuterated solvent, dimethyl sulfoxide-d6 (DMSO-d6). 1 H-NMR was performed to calculate the hydroxyl groups per gram. 1 From the results of H-NMR, a peak for the formyl group of the internal standard pentafluorobenzaldehyde was observed at 10.14 ppm, a peak for an aromatic acetylated product was observed at 2.23 ppm, and a peak for an aliphatic acetylated product was observed at 2.00 ppm.

[0072] The number (mmol / g) of functional groups (i.e., acetyl groups) in the obtained specific glycol lignin (1) is shown in Table 1. The number (mmol / g) of aromatic hydroxyl groups (-OH directly bonded to aromatic groups) was also measured by the method described above. The results are shown in Table 1.

[0073] <Examples 2 to 6> Specific glycol lignin powders (2) to (6) were obtained in the same manner as in Example 1, except that in “[1] Acetylation of glycol lignin” of Example 1, the materials (lignin, solvent, reaction reagent) used and their compositions, reaction temperature, and reaction time were changed as shown in Table 1. Table 1 shows the number of functional groups (mmol / g) and the number of aromatic hydroxyl groups (mmol / g) in the obtained specific glycol lignins (2) to (6).

[0074] <Example 7> [2] Trimethylsilylation (TMS) of glycol lignin In a 100 mL eggplant flask, 6.02 g (25.0 mmol) of glycol lignin (Lignotop SD4, manufactured by Lignomateria Co., Ltd.) and 60 mL of tetrahydrofuran (THF) were placed and stirred for 10 minutes at room temperature (20 ° C.) to completely dissolve the powder. 4.02 g of 1,1,1,3,3,3-hexamethylenedisilazane (manufactured by Tokyo Chemical Industry Co., Ltd.) was added thereto, and the inside of the eggplant flask was replaced with argon, and then the mixture was heated and stirred under reflux for 5 hours to react. After the reaction was completed, the reaction solution was added in small amounts to 400 mL of hexane to cause reprecipitation. The precipitate was collected by suction filtration, washed with 100 mL of hexane, and further vacuum dried at room temperature (20 ° C.) for 10 hours to obtain 5.09 g of brown powder of specific glycol lignin (7).

[0075] Infrared absorption spectroscopy (IR) was obtained for glycol lignin and specific glycol lignin (7). -1 The OH stretching vibration of the hydroxyl group was observed at 3400 cm for specific glycol lignin (7). -1 The absorption of 844cm was disappeared. -1 Absorption due to Si-C stretching was confirmed in the lignin. This suggests that the hydroxyl groups of glycol lignin were trimethylsilylated.

[0076] Regarding specific glycol lignin (7), 1The number of functional groups (i.e., trimethylsilyl groups) (mmol / g) and the number of aromatic hydroxyl groups (mmol / g) determined by H-NMR are shown in Table 1.

[0077] <Example 8> (Solvolysis step) 92 parts of wood flour (Japanese cedar) as lignocellulose and polyethylene glycol (HO-((CH2)2-O) m A reaction vessel equipped with a stirrer and a heater was charged with 460 parts of -CH3 (molecular weight 400) and 2.760 parts of concentrated sulfuric acid (98% by mass sulfuric acid) as a catalyst. The contents of the reaction vessel were heated to 130 to 140°C while stirring, and the reaction was carried out for 1.5 hours to solvolyze the lignocellulose and obtain a first reaction solution.

[0078] (Solution separation process) After the first reaction solution was cooled to 40° C. or lower, 550 parts of a 0.4 mol / L aqueous potassium hydroxide solution was added as an alkaline solution, and the mixture was stirred for 30 minutes to obtain a second reaction solution. Next, the second reaction solution was subjected to suction filtration to separate the solution containing glycol lignin from the solid content. At this time, the solid content was washed with water and suction filtered again to recover the glycol lignin in the solid content, thereby obtaining a solution containing glycol lignin.

[0079] (Precipitation process) To the solution containing glycol lignin, 60 parts of a 3N (1.5 mol / L) aqueous sulfuric acid solution was added as an acid solution to adjust the pH of the solution to 2, thereby obtaining a GL precipitate dispersion.

[0080] (Precipitation and separation process) The GL precipitate dispersion was filtered by suction using a belt filter (Tsukishima Kikai Co., Ltd., horizontal belt filter) to recover the precipitate containing glycol lignin. The mesh size of the endless belt filter cloth provided in the belt filter was 1.0 cc cm 3 The precipitate containing the recovered glycol lignin was dried by blowing air to obtain a powder of the specific glycol lignin (8).

[0081] Regarding specific glycol lignin (8), 1 The number of functional groups (i.e., methoxy groups) (mmol / g) and the number of aromatic hydroxyl groups (mmol / g) determined by H-NMR are shown in Table 1.

[0082] <Comparative Examples 1 to 5> The following glycol lignins were used as they were as glycol lignins (9) to (12), respectively. Comparative Example 1: Glycol lignin (Lignotop SD4, manufactured by Lignomateria Co., Ltd.), powder form Comparative Example 2: Sodium lignin sulfonate (Lignotop BSN, manufactured by Lignomateria Co., Ltd.) Comparative Example 3: Ammonium lignosulfonate (Lignotop BSA, manufactured by Lignomateria Co., Ltd.) Comparative Example 4: Calcium lignosulfonate (Lignotop BSC, manufactured by Lignomateria Co., Ltd.)

[0083] [Synthesis of resin composition] (Examples 1 to 6, 8, Comparative Examples 1 to 4) The specific glycol lignins (1) to (6) and (8) obtained in Examples 1 to 6 and 8, and the glycol lignins (9) to (12) prepared in Comparative Examples 1 to 4 were used in the amounts shown in Tables 1 and 2, respectively, and the resin and filler in the amounts shown in Tables 1 and 2 were added to a kneader having a metal kneading roll, and kneaded for 10 minutes to recover a compound. The recovered compound was pelletized by a pelletizer, and the obtained pellets were molded into a dumbbell shape by an injection molding machine.

[0084] Example 7 The specific glycol lignin (7) obtained in Example 7 was used in the amount shown in Table 1, and the silylated lignin, fumed silica, and fine powder polyethylene in the amounts shown in Table 1 were added in this order to a kneader having a metal kneading roll, and kneaded for 10 minutes. Then, di-tert-butyl peroxide was added in the amount shown in Table 1, and kneaded for 1 minute, and the compound was recovered. The recovered compound was cast onto a glass plate and degassed under reduced pressure, and then covered with a polyimide film on the surface, and reacted for 1 hour in a drying oven kept at 200 ° C. to synthesize a resin composition.

[0085] [Evaluation: Compatibility] Tensile test (stress, strain) Tensile tests were carried out to evaluate the mechanical properties of the resin compositions synthesized in each Example and Comparative Example. In Examples 1 to 6, 8, and Comparative Examples 1 to 4, molded dumbbell-shaped test pieces were used as test pieces for the measurements. In Example 7, a test piece was prepared by molding the synthesized resin composition into a strip shape with a long side of 5 cm and a short side of 0.5 cm using a cutter. Measurements were carried out for five samples of the resin composition in each Example and Comparative Example. In addition, a tensile test was also carried out in the same manner for the resin alone (i.e., a sample to which lignin was not added during the synthesis of the resin composition) as a reference. As the results of the tensile test, the stress (relative to the resin alone) and the strain (relative to the resin alone) are shown in Tables 1 and 2.

[0086] SEM observation In order to evaluate the compatibility between lignin and resin in the resin compositions synthesized in each Example and Comparative Example, cross-sections were observed using a scanning electron microscope (SEM). It was confirmed whether a sea-island structure was observed at 1000 times. The results are shown in Tables 1 and 2. Materials that do not show an island-sea structure are judged to have high compatibility.

[0087] [Evaluation: Metal adhesion] Each sample of the specific glycol lignins (1) to (8) obtained in each Example and the glycol lignins (9) to (12) prepared in each Comparative Example was placed on a stainless steel tray in an amount of 3 g. Next, a glass plate was placed on top of the sample while flattening it. The sample was flattened to have approximately the same width and thickness by visual inspection. Next, each sample was placed in a thermostatic chamber together with the stainless steel tray and held at 150°C for 30 minutes. Each sample was removed from the thermostatic chamber, and the stainless steel tray was stood up and lightly struck against a desk surface to confirm whether the sample peeled off. The results are shown in Tables 1 and 2. Those that peeled off were judged to have poor adhesion to metal.

[0088] [Table 1]

[0089] [Table 2]

[0090] In the table, "ND" means that the number of aromatic hydroxyl groups is below the detection limit. The compounds listed in Tables 1 and 2 are as follows. Acrylonitrile butadiene styrene (ABS) resin (product number: RPELLET00011080050, manufactured by Standard Test Piece Co., Ltd.) Polycarbonate (product number: RPELLET00191090050, manufactured by Standard Test Piece Co., Ltd.) Polybutylene terephthalate (PBT) (product number: RPELLET00181050050, manufactured by Standard Test Piece Co., Ltd.) Polypropylene (PP) resin (product number: RPELLET00241010050, manufactured by Standard Test Piece Co., Ltd.) Vinyl-terminated polydimethylsiloxane (DMS-V35, Gelest) Glass fiber (6mm strand, manufactured by uxcell Japan) Fumed silica (AEROSIL® RY200, manufactured by Nippon Aerosil Co., Ltd.) Fine powder polyethylene (Flo-Then (FU-4), manufactured by Sumitomo Seika Chemicals Co., Ltd.) Di-tert-butyl peroxide (Tokyo Chemical Industry Co., Ltd.)

[0091] As shown in Tables 1 and 2, the specific glycol lignins of the examples show higher compatibility with low-polarity resins than the glycol lignins of the comparative examples. It is also apparent that the specific glycol lignins of each Example have reduced adhesion to metals compared to the glycol lignin of Comparative Example 1.

Claims

1. In the molecular structure, -O-C(=O)-R １ , —O—Si(R ２ ) ３ , and -O-((CH ２ ) ｎ -O) ｍ -R ３ and having at least one group selected from -OC(=O)-R １ , the —O—Si(R ２ ) ３ and the -O-((CH ２ ) ｎ -O) ｍ -R ３ A glycol lignin having a total number of groups of 2.5 mmol / g or more and 10.0 mmol / g or less. (Note that the above R １ represents an alkyl group, ２ represents an alkyl group, ３ represents an alkyl group, and the three R ２ may be the same or different. The n represents 1 or more and 10 or less, and the m represents 10 or more and 2000 or less.

2. The glycol lignin according to claim 1, wherein the number of -OH groups directly bonded to aromatic groups in the molecular structure is 1.0 mmol / g or more.

3. A resin composition comprising the glycol lignin according to claim 1 or 2 and a resin.

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