Novolac-type phenolic resin and resin composition

Abstract

To provide a novolac phenolic resin and a resin composition that can provide a molding having excellent heat resistance and also excelling in flexibility (maximum point elongation in a bending test).SOLUTION: A novolac phenolic resin has a reaction product obtained by the reaction among polyethylene glycol-modified lignin, phenol, and aldehyde in the presence of an acid catalyst. A resin composition has the novolac phenolic resin. The novolac phenolic resin and the resin composition can provide a molding having excellent heat resistance and also excelling in flexibility (maximum point elongation in a bending test).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a novolac phenolic resin and a resin composition, and more particularly to a novolac phenolic resin and a resin composition containing the novolac phenolic resin. [Background technology]

[0002] Conventionally, thermosetting resins have been widely used in various industrial fields, such as electrical components, automobile components, building materials, daily necessities, etc. In particular, novolac-type phenolic resins are widely used as molding materials, etc., due to their excellent electrical insulation properties, heat resistance, mechanical properties, moldability, etc.

[0003] Novolac phenolic resins are obtained by reacting phenols and aldehydes in the presence of an acid catalyst. However, in recent years, there has been a demand for reducing the amount of petroleum resources used in order to protect the global environment, and the use of plant-derived raw materials as an alternative to petroleum resources has been considered.

[0004] Lignin has attracted attention as such a plant-derived raw material, and specific examples of novolac-type phenolic resins obtained using lignin include lignin-modified novolac-type phenolic resins obtained by reacting lignin with phenol or a phenol derivative and aldehydes in the presence of an organic acid (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-156601 Summary of the Invention [Problem to be solved by the invention]

[0006] On the other hand, depending on the application, thermosetting resins may be required to have further improved heat resistance as well as improved flexibility.

[0007] The present invention relates to a novolac phenolic resin and a resin composition that are excellent in heat resistance and flexibility (maximum elongation in a bending test) and that can give molded articles. [Means for solving the problem]

[0008] The present invention [1] includes a novolac-type phenolic resin containing a reaction product obtained by reacting lignin modified with polyethylene glycol, a phenol, and an aldehyde in the presence of an acid catalyst.

[0009] The present invention [2] includes the novolac phenolic resin according to the above [1], wherein the lignin is softwood lignin.

[0010] The present invention [3] includes a resin composition containing the novolac phenolic resin described in [1] or [2] above. [Effects of the Invention]

[0011] The novolac phenolic resin and resin composition of the present invention contain a reaction product obtained by reacting lignin modified with polyethylene glycol, a phenol, and an aldehyde in the presence of an acid catalyst. Therefore, the novolac phenolic resin and resin composition of the present invention can provide molded articles that are excellent in heat resistance and flexibility (maximum elongation in a bending test). DETAILED DESCRIPTION OF THE INVENTION

[0012] The novolac phenolic resin of the present invention is obtained by reacting lignin modified with polyethylene glycol (PEG) (hereinafter, sometimes referred to as PEG-modified lignin), phenols, and aldehydes in the presence of an acid catalyst.

[0013] That is, the novolac phenolic resin of the present invention is a reaction product of PEG-modified lignin, a phenol, and an aldehyde.

[0014] In the PEG-modified lignin, the polyethylene glycol (PEG) is appropriately selected depending on the physical properties required for the resin composition.

[0015] From the viewpoint of achieving both flexibility (maximum elongation in a bending test) and impact resistance, the number average molecular weight of polyethylene glycol is, for example, 100 or more, preferably 200 or more, more preferably 300 or more, and even more preferably 400 or more, and for example, 1000 or less, preferably 900 or less, more preferably 800 or less, and even more preferably 600 or less.

[0016] The number average molecular weight can be determined as a molecular weight in terms of polyethylene glycol by a known gel permeation chromatography method.

[0017] In PEG-modified lignin, lignin is a polymeric phenolic compound consisting of a basic skeleton such as guaiacyl lignin (G type), syringyl lignin (S type), or p-hydroxyphenyl lignin (H type), and is found in plants as a natural product (natural lignin).

[0018] Known examples of natural lignins extracted industrially include soda lignin, sulfite lignin, and kraft lignin, which are contained in the waste liquid (black liquor) discharged when pulp is produced from plant materials (lignocellulose) as raw materials by the soda process, sulfite process, kraft process, etc.

[0019] Specific examples of lignin include lignin derived from woody plants and lignin derived from herbaceous plants.

[0020] Examples of lignin derived from woody plants include coniferous lignin contained in coniferous trees (such as cedar), and hardwood lignin contained in hardwood.

[0021] Lignin derived from woody plants does not contain the H-type basic skeleton.

[0022] More specifically, among woody plant-derived lignins, coniferous lignins do not contain an S-type basic skeleton but have a G-type basic skeleton, while hardwood lignins have both a G-type basic skeleton and an S-type basic skeleton.

[0023] Examples of lignins derived from herbaceous plants include rice lignins contained in grass plants (wheat straw, rice straw, corn, bamboo, etc.).

[0024] Lignin derived from herbaceous plants has all the basic skeletons of H-type, G-type and S-type.

[0025] These lignins can be used alone or in combination of two or more kinds.

[0026] From the viewpoint of homogeneity of the PEG-modified lignin, the lignin is preferably a woody plant-derived lignin that does not contain an H-type basic skeleton, more preferably a coniferous lignin that does not contain an S-type basic skeleton and has a G-type basic skeleton, and particularly preferably a coniferous lignin derived from cedar.

[0027] The PEG-modified lignin is not particularly limited, but can be produced, for example, in accordance with the method described in JP 2017-197517 A.

[0028] More specifically, for example, PEG-modified lignin can be obtained by digesting plant material (lignocellulose), which is the raw material for lignin, with polyethylene glycol.

[0029] The cooking method is not particularly limited, but for example, a plant material that is the raw material for lignin, polyethylene glycol, and an inorganic acid (for example, hydrochloric acid, sulfuric acid, etc.) as an acid catalyst are mixed and reacted.

[0030] The blending ratio of polyethylene glycol is, for example, 200 parts by mass or more, preferably 300 parts by mass or more, and for example, 1000 parts by mass or less, preferably 600 parts by mass or less, per 100 parts by mass of plant material that is the raw material for lignin.

[0031] The mixing ratio of the inorganic acid (100% equivalent) per 100 parts by mass of polyethylene glycol is, for example, 0.1 parts by mass or more, preferably 0.2 parts by mass or more, and for example, 2 parts by mass or less, preferably 1 part by mass or less.

[0032] The reaction conditions are as follows: under normal pressure, the reaction temperature is, for example, 120° C. or higher, preferably 130° C. or higher, and for example, 180° C. or lower, preferably 150° C. or lower, and the reaction time is, for example, 60 minutes or longer, and for example, 240 minutes or shorter, preferably 120 minutes or shorter.

[0033] After the reaction is complete, a known alkali (for example, ammonia, sodium hydroxide, etc.) is added in an appropriate ratio to adjust the pH, and the PEG-modified lignin is extracted into the solution.

[0034] The pH after adjustment is, for example, 8 or more, preferably 10 or more, more preferably 10.5 or more, and for example, 14 or less.

[0035] By this method, pulp is obtained as a solid component, and PEG-modified lignin is obtained as a solution component (pulp waste liquor).

[0036] Next, in this method, the solid component (pulp) is separated from the reaction product by a known separation method such as filtration, pressing, or centrifugation, and the solution component (pulp waste liquor) is recovered.

[0037] Furthermore, in this method, if necessary, the solid component (pulp) can be washed and the solution (PEG-modified lignin) impregnated into the solid component can be recovered.

[0038] In this method, an inorganic acid (e.g., hydrochloric acid, sulfuric acid, etc.) is then added to adjust the pH to precipitate and deposit the PEG-modified lignin.

[0039] The pH after adjustment is, for example, 1.5 or higher, and for example, 5 or lower, preferably 3 or lower, and more preferably 2 or lower.

[0040] This allows the PEG-modified lignin to precipitate, and the resulting precipitate can be collected by a known method such as filtration, pressing, or centrifugation to obtain the PEG-modified lignin as a solid content.

[0041] Phenols include phenol and its derivatives (phenol-modified products), such as phenol, bifunctional phenol derivatives such as o-cresol, p-cresol, p-ter-butylphenol, p-phenylphenol, p-cumylphenol, p-nonylphenol, and 2,4- or 2,6-xylenol, trifunctional phenol derivatives such as m-cresol, resorcinol, and 3,5-xylenol, and tetrafunctional phenol derivatives such as bisphenol A and dihydroxydiphenylmethane. Phenol derivatives also include halogenated phenols substituted with halogens such as chlorine and bromine. These phenols can be used alone or in combination. When a phenol derivative (phenol-modified product) is used, the timing of phenol modification is not particularly limited and may be before, after, or simultaneously with the reaction of the PEG-modified lignin with the phenol and the aldehyde.

[0042] As the phenol, preferably, phenol is used.

[0043] Examples of aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, butylaldehyde (n-butylaldehyde, isobutylaldehyde), furfural, glyoxal, benzaldehyde, trioxane, and tetraoxane. Furthermore, a portion 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.

[0044] Preferred examples of the aldehydes include formaldehyde and paraformaldehyde.

[0045] 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, and for example, 99% by mass or less, preferably 95% by mass or less.

[0046] Ketones can also be blended together with aldehydes.

[0047] Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, acetophenone, diphenyl ketone, etc. These ketones can be used alone or in combination of two or more kinds.

[0048] When ketones are blended, the blending ratio of the ketones is, on a solids basis, for example, 0.01 parts by mass or more, preferably 1 part by mass or more, and for example, 200 parts by mass or less, preferably 100 parts by mass or less, per 100 parts by mass of the aldehydes.

[0049] To react the PEG-modified lignin, phenols, and aldehydes (and optionally ketones (hereinafter the same)), the above components (PEG-modified lignin, phenols, and aldehydes) are mixed and heated.

[0050] In this reaction, the blending ratio of the 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, and for example, 1000 parts by mass or less, preferably 500 parts by mass or less, more preferably 350 parts by mass or less, relative to 100 parts by mass of the PEG-modified lignin.

[0051] In other words, the blending ratio of PEG-modified lignin is, for example, 10 parts by mass or more, preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and for example, 300 parts by mass or less, preferably 200 parts by mass or less, more preferably 100 parts by mass or less, per 100 parts by mass of phenols.

[0052] From the viewpoint of improving heat resistance, the blending ratio of the phenols is preferably 200 parts by mass or more, more preferably 250 parts by mass or more, and preferably 1000 parts by mass or less, more preferably 500 parts by mass or less, relative to 100 parts by mass of the PEG-modified lignin. In other words, the blending ratio of the PEG-modified lignin is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and preferably 50 parts by mass or less, more preferably 40 parts by mass or less, relative to 100 parts by mass of the phenols.

[0053] Furthermore, from the viewpoint of improving water resistance, the blending ratio of the phenols is preferably 30 parts by mass or more, more preferably more than 50 parts by mass, and preferably 1000 parts by mass or less, more preferably 500 parts by mass or less, and even more preferably less than 250 parts by mass, relative to 100 parts by mass of the PEG-modified lignin. In other words, the blending ratio of the PEG-modified lignin is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably more than 40 parts by mass, and preferably 300 parts by mass or less, and more preferably 200 parts by mass or less, relative to 100 parts by mass of the phenols.

[0054] The blending ratio of the aldehydes relative to 100 parts by mass of the phenols is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, and for example, 35 parts by mass or less, preferably 30 parts by mass or less. The blending ratio of the aldehydes relative to 100 parts by mass of the PEG-modified lignin is, for example, 1.5 parts by mass or more, preferably 3 parts by mass or more, and for example, 350 parts by mass or less, preferably 300 parts by mass or less.

[0055] When the blending ratio of each component is within the above range, various physical properties such as mechanical properties can be improved.

[0056] In this reaction, an acid catalyst is added, that is, the above components react in the presence of an acid catalyst.

[0057] Examples of the acid catalyst include organic acids and inorganic acids.

[0058] Examples of organic acids include sulfonic acid compounds such as methanesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, cumenesulfonic acid, dinonylnaphthalene monosulfonic acid, and dinonylnaphthalenedisulfonic acid; phosphate esters having an alkyl group having 1 to 18 carbon atoms such as trimethyl phosphate, triethyl phosphate, monobutyl phosphate, dibutyl phosphate, tributyl phosphate, and trioctyl phosphate; and formic acid, acetic acid, and oxalic acid.

[0059] Examples of inorganic acids include phosphoric acid, hydrochloric acid, sulfuric acid, and nitric acid.

[0060] These acid catalysts can be used alone or in combination of two or more.

[0061] As the acid catalyst, preferably, an organic acid is used, and more preferably, oxalic acid is used.

[0062] The mixing ratio of the acid catalyst relative to 100 parts by mass of the phenols is, for example, 0.1 parts by mass or more, preferably 0.3 parts by mass or more, and for example, 10 parts by mass or less, preferably 5 parts by mass or less.

[0063] The timing of adding the acid catalyst is not particularly limited, and the acid catalyst may be added in advance to at least one of the PEG-modified lignin, phenols, and aldehydes, or may be added simultaneously when the PEG-modified lignin, phenols, and aldehydes are mixed, or may be added after the PEG-modified lignin, phenols, and aldehydes are mixed.

[0064] The reaction conditions are as follows: under atmospheric pressure, the reaction temperature is, for example, 50° C. or higher, preferably 80° C. or higher, and for example, 200° C. or lower, preferably 180° C. or lower, and the reaction time is, for example, 1 hour or higher, preferably 2 hours or higher, and for example, 20 hours or lower, preferably 15 hours or lower.

[0065] As a result, a novolac phenolic resin is obtained as a reaction product of the PEG-modified lignin, phenols, and aldehydes. More specifically, a novolac phenolic resin is obtained by the reaction of phenols with aldehydes in the presence of an acid catalyst, and the novolac phenolic resin is then modified by the PEG-modified lignin.

[0066] That is, a novolac phenolic resin modified with PEG-modified lignin (hereinafter, sometimes referred to as PEG lignin-modified novolac phenolic resin) is obtained.

[0067] In addition, in the reaction of PEG-modified lignin with phenols and aldehydes, the above components can be mixed together and reacted as described above, or the above components can be mixed sequentially and reacted.

[0068] More specifically, for example, PEG-modified lignin can be first reacted with phenols, and then the resulting reaction product can be reacted with phenols and aldehydes.

[0069] From the viewpoint of improving mechanical properties, heat resistance, and water resistance, it is preferable to sequentially mix and react the above components.

[0070] More specifically, in this method, first, PEG-modified lignin is reacted with phenols, and then the resulting reaction product is reacted with aldehydes.

[0071] In the reaction between the PEG-modified lignin and the phenols, the blending ratio of the phenols relative to 100 parts by mass of the PEG-modified lignin is, for example, 30 parts by mass or more, preferably 50 parts by mass or more, more preferably 100 parts by mass or more, and for example, 1000 parts by mass or less, preferably 500 parts by mass or less, more preferably 350 parts by mass or less.

[0072] In other words, the blending ratio of PEG-modified lignin is, for example, 10 parts by mass or more, preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and for example, 300 parts by mass or less, preferably 200 parts by mass or less, more preferably 100 parts by mass or less, per 100 parts by mass of phenols.

[0073] From the viewpoint of improving heat resistance, the blending ratio of the phenols is preferably 200 parts by mass or more, more preferably 250 parts by mass or more, and preferably 1000 parts by mass or less, more preferably 500 parts by mass or less, relative to 100 parts by mass of the PEG-modified lignin. In other words, the blending ratio of the PEG-modified lignin is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and preferably 50 parts by mass or less, more preferably 40 parts by mass or less, relative to 100 parts by mass of the phenols.

[0074] Furthermore, from the viewpoint of improving water resistance, the blending ratio of the phenols is preferably 30 parts by mass or more, more preferably more than 50 parts by mass, and preferably 1000 parts by mass or less, more preferably 500 parts by mass or less, and even more preferably less than 250 parts by mass, relative to 100 parts by mass of the PEG-modified lignin. In other words, the blending ratio of the PEG-modified lignin is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably more than 40 parts by mass, and preferably 300 parts by mass or less, and more preferably 200 parts by mass or less, relative to 100 parts by mass of the phenols.

[0075] In this reaction, the above-mentioned acid catalyst is also added.

[0076] The mixing ratio of the acid catalyst relative to 100 parts by mass of the phenols is, for example, 0.1 parts by mass or more, preferably 0.3 parts by mass or more, and for example, 10 parts by mass or less, preferably 5 parts by mass or less.

[0077] The timing of adding the acid catalyst is not particularly limited, and the acid catalyst may be added in advance to at least one of the PEG-modified lignin and the phenols, or may be added simultaneously when the PEG-modified lignin and the phenols are mixed, or may be added after the PEG-modified lignin and the phenols are mixed.

[0078] The reaction conditions are as follows: under atmospheric pressure, the reaction temperature is, for example, 60° C. or more, preferably 80° C. or more, and for example, 250° C. or less, preferably 200° C. or less, and the reaction time is, for example, 0.5 hours or more, preferably 1 hour or more, and for example, 10 hours or less, preferably 5 hours or less.

[0079] This results in the phenols being modified by the PEG-modified lignin.

[0080] In other words, the PEG-modified lignin is modified with phenols.

[0081] Next, in this method, the reaction product obtained above (i.e., phenols modified with PEG-modified lignin) is reacted with aldehydes.

[0082] In this reaction, the mixing ratio of the aldehydes is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, and for example, 35 parts by mass or less, preferably 30 parts by mass or less, per 100 parts by mass of the phenols (phenols used as raw materials in the above reaction).

[0083] In this reaction, if necessary, the above-mentioned acid catalyst can be added in an appropriate proportion.

[0084] The reaction conditions are as follows: under atmospheric pressure, the reaction temperature is, for example, 50° C. or higher, preferably 80° C. or higher, and for example, 200° C. or lower, preferably 180° C. or lower, and the reaction time is, for example, 1 hour or higher, preferably 2 hours or higher, and for example, 20 hours or lower, preferably 15 hours or lower.

[0085] This causes the phenols modified with the PEG-modified lignin to react with the aldehydes, thereby obtaining a novolac phenolic resin modified with the PEG-modified lignin (PEG lignin-modified novolac phenolic resin).

[0086] In the novolac phenolic resin, the content of the PEG-modified lignin relative to 100 parts by mass of phenols is, for example, 10 parts by mass or more, preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and for example, 300 parts by mass or less, preferably 200 parts by mass or less, more preferably 100 parts by mass or less.

[0087] In addition, from the viewpoint of improving heat resistance, the content of PEG-modified lignin is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and preferably 50 parts by mass or less, more preferably 40 parts by mass or less, per 100 parts by mass of phenols.

[0088] Furthermore, from the viewpoint of improving water resistance, the content of PEG-modified lignin is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably more than 40 parts by mass, and is preferably 300 parts by mass or less, more preferably 200 parts by mass or less, per 100 parts by mass of phenols.

[0089] In the production of the PEG lignin-modified novolac phenolic resin, unreacted raw materials (unreacted phenols, etc.) and acid catalyst can be removed, if necessary, by a known method such as distillation.

[0090] Such novolac phenolic resins contain a reaction product of polyethylene glycol-modified lignin, phenols, and aldehydes in the presence of an acid catalyst, and therefore can be used to obtain molded articles with excellent heat resistance and flexibility (maximum elongation in a bending test).

[0091] Furthermore, such novolac phenolic resins can give molded articles that are excellent in various physical properties, such as mechanical properties (such as bending properties) other than flexibility (maximum elongation in a bending test), heat resistance, electrical insulation, and water resistance.

[0092] The resin composition of the present invention contains the above-mentioned novolac phenolic resin as an essential component.

[0093] Furthermore, the resin composition may contain a phenolic resin curing agent, if necessary.

[0094] The phenol resin curing agent is not particularly limited, and any known curing agent can be used, such as hexamethylenetetramine, methylolmelamine, or methylolurea.

[0095] These phenolic resin curing agents can be used alone or in combination of two or more.

[0096] The blending ratio of the phenolic resin curing agent is appropriately set depending on the purpose and application.

[0097] The resin composition may further contain additives.

[0098] Examples of additives include known additives added to resin compositions, such as fillers (wood flour, pulp, glass fiber, etc.), colorants, plasticizers, stabilizers, and release agents (metal soaps such as zinc stearate).

[0099] These additives can be used alone or in combination of two or more. The content of the additives is appropriately set depending on the purpose and application, as long as it does not impair the excellent effects of the present invention.

[0100] For example, when a filler is added, the blending ratio of the filler relative to 100 parts by mass of the resin composition is, for example, 10 parts by mass or more, preferably 20 parts by mass or more, and for example, 300 parts by mass or less, preferably 200 parts by mass or less.

[0101] The additives may be added in advance to at least one of the PEG-modified lignin, phenols, and aldehydes, or may be added simultaneously when the PEG-modified lignin, phenols, and aldehydes are mixed, or may be added after the PEG-modified lignin, phenols, and aldehydes are mixed, or may be added directly to the reaction product thereof.

[0102] When the resin composition contains an additive, for example, the novolac phenolic resin and the additive are mixed (kneaded) by a known method.

[0103] The kneading method is not particularly limited, and for example, known kneaders such as a single-screw extruder, a multi-screw extruder, a roll kneader, a kneader, a Henschel mixer, and a Banbury mixer can be used.

[0104] As for the kneading conditions, the kneading temperature is 80° C. or higher, preferably 90° C. or higher, more preferably 100° C. or higher, and 180° C. or lower, preferably 170° C. or lower, more preferably 160° C. or lower. The kneading time is, for example, 3 minutes or longer, preferably 5 minutes or longer, and for example, 30 minutes or shorter, preferably 20 minutes or shorter.

[0105] This results in a resin composition containing the novolac phenolic resin and the additive.

[0106] The resin composition thus obtained contains the novolac phenolic resin (i.e., PEG-lignin-modified novolac phenolic resin), and therefore, the resin composition can provide a molded article having excellent heat resistance and flexibility (maximum elongation in a bending test).

[0107] Furthermore, such a resin composition can give molded articles that are excellent in various physical properties such as mechanical properties (such as bending properties) other than heat resistance and flexibility (maximum elongation in a bending test), electrical insulation, and water resistance.

[0108] Therefore, such a resin composition is suitable for use in producing molded articles.

[0109] More specifically, the resin composition is molded by a known molding method for thermosetting resins, such as transfer molding or compression molding.

[0110] The molding conditions are such that the molding temperature is, for example, 120° C. or more, preferably 150° C. or more, and for example, 250° C. or less, preferably 200° C. or less, and the molding time is, for example, 1 minute or more, preferably 5 minutes or more, and for example, 30 minutes or less, preferably 15 minutes or less.

[0111] In this method, the resulting molded product can be cured, if necessary.

[0112] The curing conditions are such that the curing temperature is, for example, 120° C. or more, preferably 150° C. or more, and for example, 250° C. or less, preferably 200° C. or less. The curing time is, for example, 30 minutes or more, preferably 60 minutes or more, and for example, 300 minutes or less, preferably 150 minutes or less.

[0113] This allows for the production of molded articles with excellent heat resistance and flexibility (maximum elongation in bending tests), which can be used in a wide range of industrial fields, including electrical parts, automobile parts, building materials, and daily necessities. [Example]

[0114] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. Furthermore, unless otherwise specified in the following description, "parts" and "%" are based on mass. Specific numerical values ​​of blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be replaced with the corresponding upper limit values ​​(numeric values ​​defined as "equal to or less than" or "less than") or lower limit values ​​(numeric values ​​defined as "equal to or more than" or "exceeding") of the blending ratios (content ratios), physical property values, parameters, etc. described in the above "Description of the Invention." <Lignins>

[0115] Production Example 1 (Mn200-PEG modified lignin) Lignin modified with polyethylene glycol having a number average molecular weight of 200 (hereinafter referred to as Mn200-PEG-modified lignin) was produced by the following method.

[0116] That is, 230 parts by mass of commercially available polyethylene glycol (PEG200) having a number average molecular weight of 200 and 0.69 parts by mass of sulfuric acid as an acid catalyst (0.3 parts by mass relative to 100 parts by mass of PEG200) were placed in a reaction vessel and stirred.

[0117] Next, 46 parts by mass of bone-dry cedar wood flour was added to the reaction vessel, and the temperature was raised to 140°C under normal pressure, and the mixture was reacted for 90 minutes with stirring.

[0118] Next, the reaction vessel was cooled, and after it was confirmed that the temperature had reached 40° C. or less, 280 parts by mass of sodium hydroxide (0.2 mol / L) was added, followed by stirring for 30 minutes.

[0119] Next, the resulting solid component (pulp) was removed using a filter press, and the solution component was recovered.

[0120] Next, sulfuric acid was added to the resulting solution component to adjust the pH to 2.0, thereby obtaining a suspension of Mn200-PEG-modified lignin.

[0121] The Mn200-PEG modified lignin was then collected by centrifugation.

[0122] Production Example 2 (Mn400-PEG modified lignin) An Mn400-PEG-modified lignin was obtained in the same manner as in Production Example 1, except that polyethylene glycol having a number average molecular weight of 400 (hereinafter, Mn400-PEG) was used instead of polyethylene glycol having a number average molecular weight of 200.

[0123] Production Example 3 (Mn600-PEG modified lignin) An Mn600-PEG-modified lignin was obtained in the same manner as in Production Example 1, except that polyethylene glycol having a number average molecular weight of 600 (hereinafter, Mn600-PEG) was used instead of polyethylene glycol having a number average molecular weight of 200.

[0124] Production Example 4 (Unmodified Lignin) Unmodified lignin was obtained as a solid by neutralizing and filtering the spent liquor (black liquor) from alkaline pulping of wheat straw.

[0125] Production Example 5 (Acetic Acid Modified Lignin) 100 parts by mass of corn stover was mixed with 1,000 parts by mass of 95% acetic acid and 3 parts by mass of sulfuric acid, and the mixture was allowed to react under reflux for 4 hours. After the reaction, the mixture was filtered to remove the pulp, and the pulp waste liquid was recovered. Next, the acetic acid in the pulp waste liquid was removed using a rotary evaporator, and the mixture was concentrated to 1 / 10 of its original volume. After that, 10 times the amount (by mass) of water as the concentrated liquid was added, and the mixture was filtered to obtain acetic acid-modified lignin as a solid.

[0126] Example 1 <Synthesis of novolac-type phenolic resin> 493.5 g of phenol was placed in a flask and heated to about 50° C. to liquefy the phenol, and then 150 g of the Mn200-PEG-modified lignin obtained in Production Example 1 was added.

[0127] Next, 7.62 g of oxalic acid (acid catalyst) and 117 g of paraformaldehyde. 4 g was added and reacted at 95°C for 2.5 hours. The temperature was then raised to 110°C at a rate of 0.5°C / min and reacted at 110°C for 1.5 hours. The temperature was then raised to 120°C at a rate of 0.5°C / min and reacted at 120°C for 2 hours.

[0128] After the reaction, 2300 g of water was added, vigorously stirred, and then the mixture was allowed to stand. The water was then removed by decantation to remove oxalic acid and phenol. Furthermore, the mixture was subjected to vacuum distillation at 120°C and 0.08 MPa while adding water as needed to remove residual phenol. Vacuum distillation was repeated until the residual phenol content was reduced to 1% or less.

[0129] As a result, a novolac-type phenolic resin modified with Mn200-PEG-modified lignin (PEG200 lignin-novolac resin) was obtained.

[0130] The amount of phenol reacted with lignins was calculated by subtracting the amount of residual phenol from the amount of phenol charged. This gave the mass ratio of phenol to lignins in the novolac phenolic resin. As a result, the ratio of lignins (L) was 25 parts by mass per 100 parts by mass of phenol (Ph) (Ph:L=100:25).

[0131] <Production of Resin Composition> 690 g of the novolac phenolic resin (PEG200 lignin-novolac resin), 230 g of wood flour (manufactured by Asahi Organic Materials Co., Ltd.) as a filler, 82.8 g of hexamethylenetetramine (manufactured by Lignite Corporation) as a phenolic resin curing agent, and 6.9 g of zinc stearate (manufactured by Wako Pure Chemical Industries, Ltd.) as a release agent were sequentially blended and kneaded with two heated rolls at 100°C for 5 minutes to obtain a resin composition.

[0132] Examples 2 to 8 A novolac phenolic resin and a resin composition were obtained in the same manner as in Example 1, except that the formulation was changed to that shown in Table 1. The mass ratio of phenol to lignins in the novolac phenolic resin was determined in the same manner as in Example 1.

[0133] Comparative Example 1 846 g of phenol, 13.02 g of oxalic acid (acid catalyst), and 172.5 g of paraformaldehyde were placed in a flask and reacted at 95°C for 2.5 hours. The temperature was then increased to 110°C at a rate of 0.5°C / min and the reaction was continued at 110°C for 1.5 hours. The temperature was then increased to 120°C at a rate of 0.5°C / min and the reaction was continued at 120°C for 2 hours.

[0134] After the reaction, 3030 g of water was added, vigorously stirred, and then the mixture was allowed to stand. The water was then removed by decantation to remove oxalic acid and phenol. Furthermore, the mixture was subjected to vacuum distillation at 120°C and 0.08 MPa while adding water as needed to remove residual phenol. Vacuum distillation was repeated until the residual phenol content was reduced to 1% or less.

[0135] As a result, a novolac phenolic resin that was not modified with PEG (unmodified novolac resin) was obtained.

[0136] In addition, 690 g of the obtained novolac type phenolic resin, 230 g of wood flour (manufactured by Asahi Organic Materials Co., Ltd.) as a filler, 82.8 g of hexamethylenetetramine (manufactured by Lignite Corporation) as a phenolic resin curing agent, and 6.9 g of zinc stearate (manufactured by Wako Pure Chemical Industries, Ltd.) as a mold release agent were sequentially blended and kneaded with two heated rolls at 100°C for 5 minutes to obtain a resin composition.

[0137] Comparative Examples 2 and 3 Novolac-type phenolic resins and resin compositions were obtained in the same manner as in Example 1, except that the formulations were changed to those shown in Table 1.

[0138] In Comparative Example 2, 150 g of unmodified lignin was used instead of the Mn200-PEG-modified lignin, thereby obtaining a novolac-type phenolic resin modified with unmodified lignin (unmodified lignin-novolac resin).

[0139] In Comparative Example 3, 150 g of acetic acid-modified lignin was used instead of the Mn200-PEG-modified lignin, thereby obtaining a novolac-type phenolic resin modified with acetic acid lignin (acetic acid lignin-novolac resin).

[0140] <Evaluation> The resin compositions obtained in each Example and Comparative Example were transfer molded at 170°C for 15 minutes, and then, in Comparative Example 1 and each Example, were further heat-cured at 180°C for 2 hours to obtain rectangular test pieces for bending tests and 75 mmφ disk-shaped test pieces for other tests. The obtained molded pieces were then evaluated by the following methods.

[0141] (1) Glass transition temperature (heat resistance, Tg) The solid dynamic viscoelasticity was measured using Rheogel-E4000 (manufactured by UBM) (frequency 1 Hz, heating rate 2°C / min). The peak temperature of the obtained tan δ curve was determined as the glass transition temperature (Tg).

[0142] (2) Maximum elongation According to JIS K6911 (1995), a three-point bending test was performed at a crosshead speed of 3 mm / min and a span of 100 mm to measure the maximum elongation. The maximum elongation is the strain (maximum elongation) when the specimen is bent until it breaks, and was calculated using the following formula:

[0143] Maximum point elongation (ε)=[6T / L 2 ] × ΔL (T: sample thickness, L: distance between supports, ΔL: bending deflection)

[0144] [Table 1] <Consideration> The molded articles obtained using the resin compositions of each Example have superior heat resistance (glass transition temperature) and flexibility (maximum elongation in bending test) compared to the molded articles obtained using the resin compositions of each Comparative Example. Also, as shown in Examples 1 to 8, the flexibility (maximum elongation in bending test) improves as the number-average molecular weight of PEG in the PEG-modified lignin increases.

[0145] <Rating 2> (3) Deflection temperature under load In accordance with ASTM D648 (2004 edition), a heat distortion tester (manufactured by Mize Testing Instruments) was used in silicone oil at a temperature rise rate of 2°C / min and a load of 18.5 kg / cm. 2 The temperature was measured when the standard deflection (0.25 mm) was reached under the above conditions.

[0146] (4) Bending strength According to JIS K6911 (1995), a three-point bending test was carried out at a crosshead speed of 3 mm / min and a span of 100 mm to measure the bending strength.

[0147] (5) Volume resistivity (electrical insulation) Volume resistivity (Ω·cm) was measured using an HP4339A (Agilent Technologies) in accordance with JIS K6911 (1995 edition).

[0148] (6) Dielectric constant The dielectric constant at a frequency of 1 GHz was measured by the capacitance method using an impedance analyzer E4991A (Agilent Technologies).

[0149] (7) Water absorption rate The initial mass (dry mass) of the molded article was measured, and then the molded article was immersed in boiling water for 2 hours, after which its mass (water-absorbed mass) and the amount of increase were measured, and the water absorption rate was calculated using the following formula.

[0150] Water absorption rate (mass%) = 100 × mass increase after immersion in boiling water / dry mass

[0151] [Table 2] <Consideration> The molded articles obtained using the resin compositions of each Example are superior in various physical properties (mechanical properties (e.g., bending properties), electrical insulation, water resistance, etc.) other than heat resistance (glass transition temperature) and flexibility (maximum elongation in bending test) compared to the molded article obtained using the resin composition of Comparative Example 1.

[0152] In particular, in the resin compositions of the examples, the higher the number average molecular weight of PEG, the more excellent the various physical properties (mechanical properties (bending properties, etc.), electrical insulation properties, water resistance, etc.).

Claims

1. A novolac phenolic resin, The novolac phenolic resin is Lignin modified with polyethylene glycol; Phenols (excluding lignin modified with polyethylene glycol), Aldehydes and in the presence of an acid catalyst, The lignin modified with polyethylene glycol is contained in a reaction product of lignin and / or a plant material that is a raw material for the lignin, and polyethylene glycol in the presence of an acid catalyst; In the novolac phenolic resin, the content of the lignin modified with polyethylene glycol is 10 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the phenols. A novolac phenolic resin characterized by:

2. 2. The novolac phenolic resin according to claim 1, wherein the lignin is a softwood lignin.

3. A composition containing the novolac phenolic resin according to claim 1 or 2. A resin composition comprising:

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