JP2020055888A - Novolak type phenolic resin, resin composition and method for producing novolak type phenolic resin - Google Patents

Abstract

To provide a novolak type phenolic resin excellent in productivity, a resin composition containing the novolak type phenolic resin, and a method for producing the novolak type phenolic resin.SOLUTION: A novolak type phenolic resin is a reaction product of a lignin having aliphatic hydroxy groups in a molecule, phenols and aldehydes under an acid catalyst, and the content ratio of the aliphatic hydroxy group of the lignin is 0.5 mass% or more and 7.0 mass% or less based on the total amount of the lignin. Such a novolak type phenolic resin and such a resin composition are excellent in productivity (such as resin yield and production speed) because a lignin having aliphatic hydroxy groups at a prescribed ratio in a molecule is used as a raw material.SELECTED DRAWING: None

Description

  The present invention relates to a novolak-type phenolic resin, a resin composition and a method for producing the novolak-type phenolic resin, and more specifically, a novolak-type phenolic resin, and a resin composition containing the novolak-type phenolic resin, and further, the novolak-type phenolic. The present invention relates to a method for producing a resin.

  Conventionally, thermosetting resins have been widely used in various industrial fields such as electric parts, automobile parts, building materials, and daily necessities. In particular, novolak-type phenol resins are widely used as molding materials and the like because of their excellent electrical insulation, heat resistance, mechanical properties, moldability, and the like.

  The novolak type phenol resin is obtained by reacting a phenol and an aldehyde under an acid catalyst. On the other hand, in recent years, from the viewpoint of protecting the global environment, it has been required to reduce the amount of petroleum resources used, and the use of plant-derived raw materials instead of petroleum resources has been studied.

  As such a plant-derived raw material, lignin has attracted attention, and as a novolak-type phenol resin obtained using lignin, specifically, for example, lignin, phenol or a phenol derivative, and aldehydes, A lignin-modified novolak-type phenolic resin obtained by reacting in the presence of an organic acid has been proposed. (See Patent Document 1 below).

JP 2008-156601 A

  On the other hand, Patent Literature 1 describes that as the lignin, kraft lignin obtained from a raw material such as wood or plant material, lignin sulfonic acid and the like can be used without limitation. For example, lignin sulfonic acid and the like are described. When used, there is a problem that the reactivity with phenols and aldehydes is poor, and the productivity (resin yield, production speed, etc.) of the lignin-modified novolak-type phenolic resin is poor.

  An object of the present invention is to provide a novolak-type phenol resin excellent in productivity, a resin composition containing the novolak-type phenol resin, and a method for producing the novolak-type phenol resin.

  The present invention [1] is a reaction product of a lignin having an aliphatic hydroxyl group in a molecule, a phenol, and an aldehyde under an acid catalyst, wherein the content of the aliphatic hydroxyl group in the lignin is: It contains novolak-type phenolic resin in an amount of 0.5% by mass or more and 7.0% by mass or less based on the total amount of the lignin.

  The present invention [2] includes the novolak phenol resin according to the above [1], which is a reaction product of the lignin-phenol composition containing the reaction product of the lignin and the phenol and the aldehyde. In.

  The present invention [3] includes the novolak-type phenol resin according to the above [1] or [2], wherein the lignin is a lignin modified with acetic acid.

  The present invention [4] includes a resin composition containing the novolak-type phenol resin according to any one of the above [1] to [3].

  The present invention [5] includes a step of reacting a lignin having an aliphatic hydroxyl group in a molecule, a phenol and an aldehyde under an acid catalyst, wherein the content of the aliphatic hydroxyl group of the lignin is The method includes a method for producing a novolak-type phenol resin, which is 0.5% by mass or more and 7.0% by mass or less based on the total amount of lignin.

  The novolak-type phenol resin and the resin composition of the present invention are excellent in productivity (resin yield, production rate, and the like) because lignin having an aliphatic hydroxyl group in a molecule is used as a raw material at a predetermined ratio.

  Further, according to the method for producing a novolak phenol resin of the present invention, a novolak phenol resin can be obtained with high productivity.

  The novolak-type phenolic resin of the present invention is obtained by reacting lignin having an aliphatic hydroxyl group (described later) in a molecule, a phenol and an aldehyde under an acid catalyst. That is, the novolak type phenol resin of the present invention is a reaction product of lignin having an aliphatic hydroxyl group (described later) in a molecule, phenol, and aldehyde.

  Lignin is a high molecular weight phenolic compound having a basic skeleton such as guaiacyl lignin (G type), syringyl lignin (S type), and p-hydroxyphenyl lignin (H type).

  More specifically, lignin is classified, for example, according to the type of plant as a raw material, and specific examples include lignin derived from woody plants and lignin derived from herbaceous plants.

  Examples of woody plant-derived lignin include coniferous lignin contained in coniferous trees (for example, cedar and the like), for example, hardwood lignin contained in hardwoods, and the like. Such woody plant-derived lignin does not include lignin having an H-type basic skeleton. For example, softwood lignin has a G-type basic skeleton, and hardwood lignin has a G-type and S-type basic skeleton. I have.

  Examples of the herbaceous plant-derived lignin include, for example, rice lignin contained in grasses, and more specifically, straw lignin contained in straw, rice straw lignin contained in rice straw, and corn. Corn lignin included, bamboo lignin included in bamboo and the like are included. Such herbaceous plant-derived lignin has H-type, G-type and S-type as its basic skeleton.

  These lignins can be used alone or in combination of two or more.

  As the lignin, preferably, a lignin derived from a herbaceous plant, more preferably a lignin derived from a herbaceous plant derived from straw, and a lignin derived from a herbaceous plant derived from corn.

  In addition, the lignin preferably contains an H-type basic skeleton in a proportion of 3% by mass or more, more preferably 9% by mass or more, and still more preferably 14% by mass or more from the viewpoint of reactivity. Can be

  Such lignin is contained in a waste liquid (black liquor) discharged when pulp is produced from a plant by a known method such as an alkali method (soda method), a sulfurous acid method, and a kraft method. More specifically, waste liquor (black liquor) discharged in the alkaline method contains alkali lignin, waste liquor (black liquor) discharged in the sulfite method contains sulfite lignin, The discharged waste liquid (black liquor) contains kraft lignin.

  Examples of the lignin include, in addition to the above, acid-modified lignin obtained by modifying lignin with an acid (such as a carboxylic acid), and explosive lignin obtained by treating a plant by an explosion method.

  As the lignin, preferably, an acid-modified lignin is used, and more preferably, a carboxylic acid-modified lignin is used.

  In the carboxylic acid-modified lignin, as the carboxylic acid, for example, a carboxylic acid having one carboxy group (hereinafter sometimes referred to as a monofunctional carboxylic acid) may be mentioned. Functional carboxylic acids, unsaturated aliphatic monofunctional carboxylic acids, aromatic monofunctional carboxylic acids and the like can be mentioned.

  Examples of the saturated aliphatic monofunctional carboxylic acid include acetic acid, propionic acid, butyric acid, lauric acid and the like.

  Examples of the unsaturated aliphatic monofunctional carboxylic acid include acrylic acid, methacrylic acid, linoleic acid and the like.

  Examples of the aromatic monofunctional carboxylic acid include benzoic acid, 2-phenoxybenzoic acid, 4-methylbenzoic acid, and the like.

  These carboxylic acids can be used alone or in combination of two or more.

  As the carboxylic acid, preferably, a saturated aliphatic monofunctional carboxylic acid, more preferably, acetic acid is used (in other words, lignin modified with acetic acid is used as lignin). By using the above carboxylic acid, carboxylic acid-modified lignin can be easily obtained, and the obtained carboxylic acid-modified lignin has relatively high solubility in an organic solvent, as described later, and has a melting temperature of Since the temperature is relatively low (about 100 to 200 ° C.), the handleability is excellent.

  The carboxylic acid can be prepared as an aqueous solution. In such a case, the concentration of the carboxylic acid aqueous solution is not particularly limited, and is appropriately set.

  The method for producing the carboxylic acid-modified lignin is not particularly limited, and can be based on a known method.

  Specifically, for example, by digesting a plant material (eg, conifer, hardwood, grass, etc.) as a raw material of lignin using a carboxylic acid (preferably, acetic acid), an aliphatic hydroxyl group of lignin ( ) Can be modified with carboxylic acid to obtain carboxylic acid-modified lignin as pulp waste liquid.

  The cooking method is not particularly limited. For example, a plant material as a raw material of lignin is mixed with a carboxylic acid and an inorganic acid (eg, hydrochloric acid, sulfuric acid, etc.) and reacted.

  The mixing ratio of the carboxylic acid is such that the carboxylic acid (100% conversion) is, for example, 500 parts by mass or more, preferably 900 parts by mass or more with respect to 100 parts by mass of the plant material used as the raw material of lignin, for example, 30000. It is at most 1 part by mass, preferably at most 15,000 parts by mass.

  The mixing ratio of the inorganic acid is such that the inorganic acid (100% conversion) is, for example, 0.01 part by mass or more, preferably 0.05 part by mass or more based on 100 parts by mass of the plant material used as a raw material of lignin. And, for example, 10 parts by mass or less, preferably 5 parts by mass or less.

  As the reaction conditions, the reaction temperature is, for example, 30 ° C. or higher, preferably 50 ° C. or higher, for example, 400 ° C. or lower, preferably 250 ° C. or lower under atmospheric pressure. The reaction time is, for example, 0.5 hours or more, preferably 1 hour or more, for example, 20 hours or less, preferably 10 hours or less.

  By such cooking, pulp is obtained, and carboxylic acid-modified lignin is obtained as pulp waste liquid.

  Next, in this method, the pulp is separated by a known separation method such as filtration, the filtrate (pulp waste liquid) is collected, and if necessary, unreacted carboxylic acid is removed by a known method using, for example, a rotary evaporator, vacuum distillation, or the like. (Removed) by the method described in (1). Thereafter, a large excess of water is added to precipitate the carboxylic acid-modified lignin, and the carboxylic acid-modified lignin is collected as a solid by filtration.

  Further, the method for obtaining carboxylic acid-modified lignin is not limited to the above. For example, lignin not modified with carboxylic acid (for example, the above-mentioned alkali lignin, the above-mentioned sulfite lignin, the above-mentioned kraft lignin, etc. (hereinafter, unmodified lignin) ) And a carboxylic acid, thereby modifying an aliphatic hydroxyl group (described later) of the lignin with a carboxylic acid to obtain a carboxylic acid-modified lignin.

  In such a method, the unmodified lignin is preferably a powdery unmodified lignin.

  The average particle size of the powdery unmodified lignin is, for example, 0.1 μm or more, preferably 5 μm or more, for example, 1000 μm or less, preferably 500 μm or less.

  When the average particle size is in the above range, aggregation of the unmodified lignin can be suppressed, and the unmodified lignin can be favorably dispersed in the carboxylic acid.

  The powdery unmodified lignin can be obtained by drying and pulverizing a lump of unmodified lignin by a known method, or a commercially available product can be used.

  As a method of reacting unmodified lignin and carboxylic acid, for example, unmodified lignin is mixed with a carboxylic acid and an inorganic acid (eg, hydrochloric acid, sulfuric acid, etc.) and reacted.

  The mixing ratio of the carboxylic acid is such that the carboxylic acid (100% conversion) is, for example, 300 parts by mass or more, preferably 500 parts by mass or more, for example, 15,000 parts by mass or less, based on 100 parts by mass of unmodified lignin. Preferably, it is 10,000 parts by mass or less.

  Further, the mixing ratio of the inorganic acid is such that the inorganic acid (100% conversion) is, for example, 0.01 parts by mass or more, preferably 0.05 parts by mass or more with respect to 100 parts by mass of the unmodified lignin. 10 parts by mass or less, preferably 5 parts by mass or less.

  As the reaction conditions, the reaction temperature is, for example, 30 ° C. or higher, preferably 50 ° C. or higher, for example, 400 ° C. or lower, preferably 250 ° C. or lower under atmospheric pressure. The reaction time is, for example, 0.5 hours or more, preferably 1 hour or more, for example, 20 hours or less, preferably 10 hours or less.

  Such carboxylic acid-modified lignin is excellent in handleability.

  That is, lignin that has not been modified with a carboxylic acid has relatively low solubility in an organic solvent and does not melt.

  On the other hand, lignin modified with a carboxylic acid as described above is an organic solvent (eg, esters such as methyl acetate, ethyl acetate, butyl acetate, and isobutyl acetate; for example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone). , For example, aliphatic alcohols such as methanol, for example, phenols such as phenol, cresol, and bisphenol A, for example, ethers such as diethyl ether, tetrahydrofuran, dioxane, for example, methyl cellosolve acetate, ethyl cellosolve acetate, methyl carb Tall acetate, ethyl carbitol acetate, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, 3-methyl-3-methoxybutyl Glycol ether esters such as acetate and ethyl-3-ethoxypropionate, for example, nitriles such as acetonitrile, and others, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, hexa It has relatively high solubility in polar solvents such as methylphosphonylamide, and can be melted at a relatively low temperature (about 100 to 200 ° C.), so that it is excellent in handleability.

  Therefore, the carboxylic acid-modified lignin can be used as a solution of the above organic solvent. In such a case, the concentration of the carboxylic acid-modified lignin in the solution is, for example, 10% by mass or more, preferably 30% by mass or more.

  The average particle size of the carboxylic acid-modified lignin is, for example, 0.1 μm or more, preferably 5 μm or more, for example, 2 cm or less, preferably 1 cm or less.

  The carboxylic acid-modified lignin is obtained as a mixture of a component (soluble component) soluble in the above organic solvent (preferably ethyl acetate) and a component (insoluble component) insoluble in the above organic solvent. There are cases.

  In such a case, a mixture of a soluble component and an insoluble component (referred to as crude carboxylic acid-modified lignin) can be used as the carboxylic acid-modified lignin.

  Further, the soluble component and the insoluble component can be separated and only the soluble component can be used, or only the insoluble component can be used. Further, the separated soluble component and insoluble component can be mixed and used.

  The carboxylic acid-modified lignin preferably includes a soluble component.

  As a method for separating the soluble component and the insoluble component, for example, the above-described extraction method using an organic solvent is employed.

  The extraction conditions are appropriately set according to the organic solvent used, the physical properties of the crude carboxylic acid-modified lignin, and the like.

  Lignin (unmodified lignin, carboxylic acid-modified lignin, etc.) has an aliphatic hydroxyl group in the molecule.

  An aliphatic hydroxyl group is a hydroxyl group that is not directly bonded to an aromatic ring but directly bonded to an aliphatic hydrocarbon, and is distinguished from a hydroxyl group that is directly bonded to an aromatic ring (aromatic hydroxyl group (phenolic hydroxyl group)).

  The content ratio of the aliphatic hydroxyl group of lignin is 0.5% by mass or more, preferably 3.0% by mass or more, and 7.0% by mass or less, preferably 5.5% by mass based on the total amount of lignin. % Or less.

  When the content ratio of the aliphatic hydroxyl group of lignin is less than the above lower limit, the reactivity between lignin and phenols and the reactivity between lignin and aldehydes are inferior, and the productivity of novolak-type phenol resin decreases.

  On the other hand, when the content ratio of the aliphatic hydroxyl group of lignin is higher than the above upper limit, gelation is apt to occur during the reaction of lignin, phenols and aldehydes, so that the productivity of the novolak type phenol resin decreases.

  On the other hand, when the content ratio of the aliphatic hydroxyl group of lignin is in the above range, the reactivity between lignin and phenols, the reactivity between lignin and aldehydes are excellent, and gelation is unlikely to occur during the reaction. And the productivity of the novolak phenolic resin is improved.

  In addition, the content ratio of the aliphatic hydroxyl group is determined based on Examples described later.

  The lignin containing an aliphatic hydroxyl group in the above range preferably includes carboxylic acid-modified lignin derived from herbaceous plants, and more preferably acetic acid-modified lignin derived from herbaceous plants.

  Phenols are phenol and derivatives thereof, for example, phenol, and further, for example, o-cresol, p-cresol, p-ter-butylphenol, p-phenylphenol, p-cumylphenol, p-nonylphenol, 2,4- or 2,6-xylenol, m-cresol, resorcinol, 3,5-xylenol, bisphenol A, dihydroxydiphenylmethane and the like. Further, for example, halogenated phenols substituted by halogen such as chlorine and bromine are also included. These phenols can be used alone or in combination of two or more.

  Phenols are preferably phenols.

  Examples of the aldehyde include formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, butyraldehyde (n-butyraldehyde, isobutyraldehyde), furfural, glyoxal, benzaldehyde, trioxane, tetraoxane, and the like. Further, a part of the aldehyde may be substituted with furfuryl alcohol or the like. These aldehydes can be used alone or in combination of two or more.

  Preferably, the aldehydes include formaldehyde and paraformaldehyde.

  The aldehydes can be used, for example, as an aqueous solution. In such a case, the concentration of the aldehydes is, for example, 10% by mass or more, preferably 20% by mass or more, for example, 99% by mass or less, preferably 95% by mass or less.

  Also, ketones can be blended together with aldehydes.

  Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, acetophenone, diphenyl ketone, and the like. These ketones can be used alone or in combination of two or more.

  When ketones are blended, the blending ratio of the ketones is, based on the solid content, based on 100 parts by mass of the aldehydes, for example, 0.01 parts by mass or more, preferably 1 part by mass or more. It is at most 200 parts by mass, preferably at most 100 parts by mass.

  Then, in order to react lignin (lignin having an aliphatic hydroxyl group in the molecule) with phenols and aldehydes (and ketones blended as necessary (the same applies hereinafter)), the above components (lignin, phenols) And aldehydes) are mixed and heated.

  In this reaction, the mixing ratio of phenols is, for example, 30 parts by mass or more, preferably 50 parts by mass or more, more preferably 100 parts by mass or more, based on 100 parts by mass of lignin, for example, 1000 parts by mass. The amount is preferably 500 parts by mass or less, more preferably 350 parts by mass or less.

  Further, the mixing ratio of the aldehydes is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, for example, 35 parts by mass or less, preferably 30 parts by mass or less based on 100 parts by mass of the phenols. is there. Further, the mixing ratio of the aldehydes is, for example, 1.5 parts by mass or more, preferably 3 parts by mass or more, for example, 350 parts by mass or less, preferably 300 parts by mass or less based on 100 parts by mass of lignin. It is.

  When the compounding ratio of each component is in the above range, various physical properties (electrical insulation, mechanical properties, heat resistance, water resistance, etc.) can be improved.

  In this reaction, an acid catalyst is added. That is, the above components react under an acid catalyst.

  Examples of the acid catalyst include an organic acid and an inorganic acid.

  Examples of the organic acid include sulfonic acid compounds such as methanesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, cumenesulfonic acid, dinonylnaphthalenemonosulfonic acid, and dinonylnaphthalenedisulfonic acid, for example, trimethyl phosphate, Phosphoric esters having an alkyl group having 1 to 18 carbon atoms, such as triethyl phosphate, monobutyl phosphate, dibutyl phosphate, tributyl phosphate, and trioctyl phosphate, for example, formic acid, acetic acid, and oxalic acid.

  Examples of the inorganic acid include phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid and the like.

  These acid catalysts can be used alone or in combination of two or more.

  Preferably, the acid catalyst is an organic acid, more preferably oxalic acid.

  The compounding ratio of the acid catalyst is, for example, 0.1 parts by mass or more, preferably 0.3 parts by mass or more, for example, 10 parts by mass or less, preferably 100 parts by mass, based on 100 parts by mass of the phenols. , 7 parts by mass or less.

  The timing of addition of the acid catalyst is not particularly limited, and may be added in advance to at least one of lignin, phenols and aldehydes, or may be added at the same time as lignin, phenols and aldehydes are blended. And may be added after blending of lignin, phenols and aldehydes.

  Regarding the reaction conditions, the reaction temperature is, for example, 50 ° C. or higher, preferably 80 ° C. or higher, for example, 200 ° C. or lower, preferably 180 ° C. or lower under atmospheric pressure. The reaction time is, for example, 1 hour or more, preferably 2 hours or more, for example, 20 hours or less, and preferably 15 hours or less.

  Thereby, a novolak-type phenol resin is obtained as a reaction product of lignin, phenols and aldehydes.

  More specifically, a novolak-type phenol resin is obtained by a reaction between a phenol and an aldehyde under an acid catalyst, and the novolak-type phenol resin is modified with lignin.

  That is, a novolak-type phenol resin modified with lignin (hereinafter sometimes referred to as a lignin-modified novolak-type phenol resin) is obtained.

  In the reaction between lignin, phenols, and aldehydes, the above components can be mixed and reacted (lump reaction) as described above. However, the above components can be sequentially mixed and reacted (sequential reaction). ).

  In the sequential reaction, specifically, first, lignin and phenols are reacted to prepare a lignin-phenol composition containing a reaction product of lignin and phenols, and then the lignin-phenol composition and an aldehyde React with the kind.

  In the reaction between lignin and phenols, phenols are mixed in an excess equivalent to lignin. Specifically, the mixing ratio of phenols is, for example, 30 parts by mass or more, preferably 100 parts by mass or more, preferably 100 parts by mass of lignin. , 50 parts by mass or more, for example, 1000 parts by mass or less, preferably 500 parts by mass or less.

  In this reaction, the above-mentioned acid catalyst is added.

  The mixing ratio of the acid catalyst is, for example, 0.1 part by mass or more, preferably 0.3 part by mass or more, for example, 10 parts by mass or less, preferably 5 parts by mass with respect to 100 parts by mass of the phenol. It is as follows.

  The timing of addition of the acid catalyst is not particularly limited, and may be added in advance to at least one of lignin and phenols, or may be added at the same time as lignin and phenols are blended. It may be added after blending of lignin and phenols.

  Regarding the reaction conditions, the reaction temperature is, for example, 60 ° C. or higher, preferably 80 ° C. or higher under atmospheric pressure, for example, 250 ° C. or lower, preferably 200 ° C. or lower. The reaction time is, for example, 0.5 hours or more, preferably 1 hour or more, for example, 10 hours or less, preferably 5 hours or less.

  By this reaction, lignin is modified by phenols. Specifically, an aliphatic hydroxyl group in a molecule of lignin (including a hydroxyl group modified with carboxylic acid and an aliphatic hydroxyl group remaining without being modified with carboxylic acid when lignin is carboxylic acid-modified lignin) ) Is replaced by phenols.

  In the above reaction, excess phenols remain as unreacted components. Therefore, the lignin-phenol composition obtained by the above reaction contains a reaction product of lignin and phenols (lignin modified by phenols) and free phenols.

  Next, in this method, the lignin-phenol composition obtained above (that is, lignin modified with phenols and free phenols) is reacted with aldehydes.

  In this reaction, the mixing ratio of the aldehyde is, for example, 5 parts by mass or more, preferably 10 parts by mass or more with respect to 100 parts by mass of phenols (phenols used as a raw material in the above reaction). , 35 parts by mass or less, preferably 30 parts by mass or less.

  In this reaction, the above acid catalyst can be added at an appropriate ratio, if necessary.

  Regarding the reaction conditions, the reaction temperature is, for example, 50 ° C. or higher, preferably 80 ° C. or higher, for example, 200 ° C. or lower, preferably 180 ° C. or lower under atmospheric pressure. The reaction time is, for example, 1 hour or more, preferably 2 hours or more, for example, 20 hours or less, and preferably 15 hours or less.

  As a result, the lignin-phenol composition reacts with the aldehyde, and a novolak-type phenol resin modified with lignin (lignin-modified novolak-type phenol resin) is obtained.

  According to the above-described sequential reactions, improvement in heat resistance, electrical insulation, and water resistance can be achieved.

  In the production of the lignin-modified novolak-type phenol resin, if necessary, unreacted raw materials (unreacted phenols and the like) and an acid catalyst can be removed by a known method such as distillation.

  Such a novolak-type phenol resin (that is, a lignin-modified novolak-type phenol resin) uses lignin having an aliphatic hydroxyl group in a molecule at a predetermined ratio as a raw material, and therefore has a low productivity (resin yield, production rate, etc.). Excellent. Further, it is possible to obtain a molded product excellent in various physical properties (electrical insulation, mechanical properties, heat resistance, water resistance, etc.).

  Further, according to the above-mentioned method for producing a novolak phenol resin, a novolak phenol resin can be obtained with good productivity (resin yield, production rate, etc.).

  The resin composition of the present invention contains the novolak phenol resin as an essential component.

  Further, the resin composition can contain a phenol resin curing agent, if necessary.

  The phenol resin curing agent is not particularly limited, and a known curing agent can be used. Specific examples include hexamethylenetetramine, methylolmelamine, methylolurea, and phenol novolak.

  These phenolic resin curing agents can be used alone or in combination of two or more.

  The mixing ratio of the phenol resin curing agent is appropriately set according to the purpose and use.

  Further, the resin composition can further contain an additive.

  As the additives, known additives added to the resin composition, known additives such as fillers (wood flour, pulp, glass fiber, etc.), coloring agents, plasticizers, stabilizers, release agents ( Metal soap such as zinc stearate).

  These additives can be used alone or in combination of two or more. The content of the additive is appropriately set according to the purpose and use within a range that does not impair the excellent effects of the present invention.

  For example, when a filler is added, the mixing ratio thereof is, for example, 10 parts by mass or more, preferably 20 parts by mass or more with respect to 100 parts by mass of the resin composition. It is at most 500 parts by mass, preferably at most 300 parts by mass.

  The additives may be added in advance to at least one of lignin, phenols and aldehydes, or may be added at the same time as the lignin, phenols and aldehydes are blended. May be added after compounding the aldehydes and aldehydes, or may be added directly to their reaction products.

  Since the resin composition thus obtained contains the above-mentioned novolak-type phenol resin (that is, lignin-modified novolak-type phenol resin), it is excellent in productivity and various physical properties.

  Therefore, such a resin composition is suitably used for manufacturing a molded article.

  More specifically, the above-mentioned resin composition is molded by a known thermosetting resin molding method such as transfer molding and compression molding. Thereby, a molded article excellent in various physical properties can be obtained.

  Therefore, the obtained molded article can be widely used in various industrial fields such as electric parts, automobile parts, building materials, and daily necessities.

  Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. In the following description, “parts” and “%” are based on mass unless otherwise specified. Specific numerical values such as the mixing ratio (content ratio), physical property values, and parameters used in the following description are the mixing ratios (corresponding to those described in the above-mentioned “Embodiments of the Invention”). Substitute the upper limit value (value defined as “less than” or “less than”) or the lower limit value (value defined as “over” or “exceeding”) such as content ratio, physical property value, parameter, etc. be able to.

<<< content ratio of aliphatic hydroxyl group >>>
The content ratio of the aliphatic hydroxyl group to the total amount of lignin was measured by the following method.

  That is, first, 5 mL each of pyridine and acetic anhydride was added to 500 mg of lignin and left at room temperature for 24 hours to acetylate the hydroxyl group. Then, pyridine and acetic anhydride were removed by an evaporator while adding toluene.

  Thereafter, 5 mg of acetylated lignin was dissolved in 1 g of a solvent, and proton NMR measurement was performed under the following conditions to quantify the amount of acetyl group protons appearing at about 1.9 ppm. On the other hand, lignin not acetylated was also subjected to proton NMR measurement under the same conditions, and the amount of acetyl group protons was quantified.

Then, the peak intensity at about 1.9 ppm of non-acetylated lignin was subtracted from the peak intensity at about 1.9 ppm of acetylated lignin to obtain the peak amount due to acetylation. This was defined as the amount of the aliphatic hydroxyl group.
Apparatus: Bruker Ltd. AscendTM 400 NMR apparatus _{solvent: D 2 O37.5g + NaOD12.5g + DSS} -d 6 (3- ( trimethylsilyl) -1-propane _{-1,1,2,2,3,3-d 6} - sulfonate, sodium Standard substance) 25mg
Measurement frequency: 400MHz
Measurement temperature: 25 ° C
Number of scans: 128 << Resin yield >>
The yield of the novolak type phenol resin was calculated by the following equation.

Resin yield (%) = [mass of the obtained novolak-type phenol resin] ÷ [total mass of raw materials used] × 100
<< Lignin production >>
Production Example 1 (lignin acetate)
100 parts by mass of corn stover was mixed with 1000 parts by mass of 95% by mass of acetic acid and 3 parts by mass of sulfuric acid, and reacted under reflux for 4 hours. After the reaction, the pulp was removed by filtration, and the pulp waste liquid was recovered. Next, acetic acid in the pulp waste liquid was removed using a rotary evaporator, and the pulp waste liquid was concentrated until the volume became 1/10. Then, 10 times the amount of the concentrated liquid (by mass) was added, and filtration was performed. Acetic acid-modified lignin was obtained as a solid content.

  The aliphatic hydroxyl group content of the acetic acid-modified lignin was 5.1% by mass.

Production Example 2 (alkaline lignin)
After neutralizing the alkaline pulp waste liquor (black liquor) of straw, filtration was performed to obtain alkali lignin as a solid content.

  The content ratio of aliphatic hydroxyl groups in the alkali lignin was 3.1% by mass.

<Sequential reaction>
Example 1
493.5 g of phenol was placed in a flask and heated to about 50 ° C. to liquefy the phenol. Thereafter, 150 g of the lignin acetate obtained in Production Example 1 was added.

  Next, 7.62 g of oxalic acid (acid catalyst) was added, and the mixture was reacted at 130 ° C. for 2.5 hours. Thus, the acetic acid-modified lignin was modified with phenol.

  Thereafter, the mixture was cooled to 80 ° C., 117.4 g of paraformaldehyde was added, and the mixture was reacted at 95 ° C. for 2.5 hours. Next, the temperature was raised to 110 ° C at a rate of 0.5 ° C / min, and the reaction was performed at 110 ° C for 1.5 hours. Next, the temperature was raised to 120 ° C. at a rate of 0.5 ° C./min, and the reaction was performed at 120 ° C. for 2 hours.

  After the reaction, 2300 g of water was added, the mixture was stirred vigorously, and then allowed to stand. Then, oxalic acid and phenol were removed by removing water by decantation. Furthermore, distillation was performed under reduced pressure at 120 ° C. and 0.08 MPa while adding water as appropriate to remove residual phenol. The distillation under reduced pressure was repeated until the residual ratio of phenol became 1% or less.

  Thus, a novolak-type phenol resin modified with acetic acid-modified lignin was obtained.

  The yield of the novolak-type phenol resin was 74.9%.

  Further, 450 g of the obtained resin, 150 g of wood powder (manufactured by Asahi Organic Materials Co., Ltd.) as a filler, 54 g of hexamethylenetetramine (manufactured by Lignite) as a phenol resin curing agent, and stearic acid as a release agent 4.5 g of zinc (manufactured by Wako Pure Chemical Industries, Ltd.) were sequentially mixed and kneaded with two hot rolls at 100 ° C. for 10 minutes to obtain a resin composition.

Examples 2 to 4 and Comparative Example 1
A novolak-type phenolic resin and a resin composition were obtained in the same manner as in Example 1 except that the formulation shown in Table 1 was used.

  In Example 2, the alkali lignin obtained in Production Example 2 was used instead of lignin acetate.

  In Example 3, Kraft lignin (manufactured by SIGMA-ALDRICH, aliphatic hydroxyl group content: 4.4% by mass) was used instead of lignin acetate.

  In Comparative Example 1, sodium ligninsulfonate (manufactured by Tokyo Chemical Industry Co., Ltd., aliphatic hydroxyl group content: 0.3% by mass) was used instead of lignin acetate.

<Batch reaction>
Example 4
493.5 g of phenol was placed in a flask and heated to about 50 ° C. to liquefy the phenol. Thereafter, 150 g of the acetic acid-modified lignin obtained in Production Example 1 was added.

  Next, 7.62 g of oxalic acid (acid catalyst) and 117.4 g of paraformaldehyde were added and reacted at 95 ° C. for 2.5 hours. Next, the temperature was raised to 110 ° C at a rate of 0.5 ° C / min, and the reaction was performed at 110 ° C for 1.5 hours. Next, the temperature was raised to 120 ° C. at a rate of 0.5 ° C./min, and the reaction was performed at 120 ° C. for 2 hours.

  After the reaction, 2300 g of water was added, and the mixture was vigorously stirred and allowed to stand, and oxalic acid and phenol were removed by removing water by decantation. Furthermore, distillation was performed under reduced pressure at 120 ° C. and 0.08 MPa while adding water as appropriate to remove residual phenol. The distillation under reduced pressure was repeated until the residual ratio of phenol became 1% or less.

  Thus, a novolak-type phenol resin modified with acetic acid-modified lignin was obtained.

  The yield of the novolak-type phenol resin was 69.7%.

  Further, 450 g of the obtained resin, 150 g of wood powder (manufactured by Asahi Organic Materials Co., Ltd.) as a filler, 54 g of hexamethylenetetramine (manufactured by Lignite) as a phenol resin curing agent, and stearic acid as a release agent 4.5 g of zinc (manufactured by Wako Pure Chemical Industries, Ltd.) was sequentially mixed and kneaded with two hot rolls at 100 ° C. for 10 minutes to obtain a resin composition.

Example 5
A novolak-type phenolic resin and a resin composition were obtained in the same manner as in Example 4, except that the formulation shown in Table 2 was used.

  In Example 5, the alkali lignin obtained in Production Example 2 was used instead of lignin acetate.

Comparative Example 2
846 g of phenol, 13.02 g of oxalic acid (acid catalyst) and 172.5 g of paraformaldehyde were put in a flask, and reacted at 95 ° C. for 2.5 hours. Next, the temperature was raised to 110 ° C at a rate of 0.5 ° C / min, and the reaction was performed at 110 ° C for 1.5 hours. Next, the temperature was raised to 120 ° C. at a rate of 0.5 ° C./min, and the reaction was performed at 120 ° C. for 2 hours.

  After the reaction, 3030 g of water was added, and the mixture was vigorously stirred and allowed to stand, and oxalic acid and phenol were removed by removing water by decantation. Furthermore, distillation was performed under reduced pressure at 120 ° C. and 0.08 MPa while adding water as appropriate to remove residual phenol. The distillation under reduced pressure was repeated until the residual ratio of phenol became 1% or less.

  Thus, a novolak-type phenol resin containing no lignin was obtained.

  The yield of the novolak type phenol resin was 60.1%.

  Further, 450 g of the obtained resin, 150 g of wood flour (manufactured by Asahi Organic Materials Co., Ltd.) as a filler, 54 g of hexamethylenetetramine (manufactured by Lignite) as a curing agent, and zinc stearate as a release agent ( 4.5 g of Wako Pure Chemical Industries, Ltd.), and kneaded with two hot rolls at 100 ° C. for 10 minutes to obtain a resin composition.

<Evaluation>
The resin compositions obtained in each of the examples and comparative examples were subjected to transfer molding at 170 ° C. for 15 minutes to obtain rectangular test pieces for bending tests and disk-shaped test pieces of 75 mmφ as molded products.

  Then, the obtained molded product was evaluated by the following method. Table 1 shows the results.

(1) Glass transition temperature (Tg)
Using Rheogel-E4000 (manufactured by UBM), the solid dynamic viscoelasticity was measured (frequency: 1 Hz, heating rate: 2 ° C./min). Then, the peak temperature of the obtained tan δ curve was determined as a glass transition temperature (Tg). Table 1 shows the results.

(2) Bending strength The bending strength was measured at a crosshead speed of 3 mm / min and a span of 100 mm in accordance with JIS K6911 (1995 version).

(3) Deflection temperature under load According to ASTM D648 (2004 version), using a heat distortion tester (manufactured by Mize Tester), in silicone oil, at a temperature increase rate of 2 ° C./min and a load of 18.5 kg / cm ² . Then, the temperature when the standard deflection (0.25 mm) was reached was measured.

(4) Coefficient of linear expansion TMA / SS6000 (manufactured by Hitachi High-Tech Science Corporation) was used to perform thermomechanical analysis (TMA) under a nitrogen atmosphere in a compression mode at a heating rate of 2 ° C./min. The linear expansion coefficient at 40 ° C to 60 ° C was determined.

(5) Volume resistivity (electrical insulation)
According to JIS K6911 (1995 version), volume resistivity (Ω · cm) was measured using HP4339A (manufactured by Agilent Technologies).

(6) Dielectric constant The dielectric constant at a frequency of 1 GHz was measured by a capacitance method using an impedance analyzer E4991A (manufactured by Agilent Technologies).

(7) Water absorption The initial mass (dry mass) of the molded article was measured, and then the molded article was immersed in boiling water for 2 hours, and then its mass (water absorption mass) and increase were measured. The rate was determined.

Water absorption (mass%)
= 100 x the amount of increase in mass after immersion in boiling water / dry mass

Claims (5)

Lignin having an aliphatic hydroxyl group in the molecule,
Phenols,
An acid catalyzed reaction product with an aldehyde,
A novolak-type phenol resin, wherein the content of the aliphatic hydroxyl group in the lignin is 0.5% by mass or more and 7.0% by mass or less based on the total amount of the lignin. A lignin-phenol composition comprising the reaction product of the lignin and the phenols;
The novolak type phenol resin according to claim 1, which is a reaction product with the aldehyde. The lignin is lignin modified with acetic acid,
The novolak-type phenol resin according to claim 1.   A resin composition comprising the novolak-type phenol resin according to claim 1. Including a step of reacting lignin having an aliphatic hydroxyl group in the molecule, phenols, and aldehydes under an acid catalyst,
A method for producing a novolak-type phenol resin, wherein a content ratio of the aliphatic hydroxyl group in the lignin is 0.5% by mass or more and 7.0% by mass or less based on a total amount of the lignin.