Method for fractionating phenolic resin, method for producing phenolic resin, and solvent for fractionating phenolic resin

Abstract

The purpose of the present invention is to provide: a method for fractionating a phenolic resin by using a solvent that is easier to handle; a method for producing a phenolic resin; and a solvent for fractionating a phenolic resin. A method for fractionating a phenolic resin according to the present invention comprises an extraction step for mixing a resin liquid, obtained by dissolving a phenolic resin in a solvent A, with a solvent B, and extracting low-molecular-weight components of the phenolic resin into the solvent B, wherein when SPA is the weighted average of the SP values of a solvent component AN constituting the solvent A, as measured by the Fedors method, and SPB is the weighted average of the SP values of a solvent component BN constituting the solvent B, as measured by the Fedors method, (1) SPA≤9.5 and (2) 14.0≤SPB≤20.5 are satisfied. Moreover, this method for producing a phenolic resin involves said method for fractionating a phenolic resin.

Description

[Technical Field]

[0001] The present invention relates to a method for fractionating phenolic resins, a method for producing phenolic resins, and a solvent for fractionating phenolic resins. More specifically, the invention relates to a fractionation method and a solvent for fractionating low molecular weight components from phenolic resins, and to a method for producing phenolic resins using this fractionation method. [Background technology]

[0002] Unrefined phenolic resins contain a wide range of molecular weight components, from low molecular weight components such as low nuclei (unreacted monomers, dimers, trimers, etc.) to high molecular weight components with a high degree of polymerization. From the perspective of fluidity, low molecular weight components function as factors that increase the fluidity of phenolic resins. Therefore, phenolic resins with a high proportion of low molecular weight components can have easy-to-handle fluidity. On the other hand, from the perspective of curability, low molecular weight components are components that do not easily contribute to crosslinking during curing, and thus become a factor that reduces curing properties. In addition, when heat curing is performed, sublimation of low molecular weight components can be a problem. Thus, phenolic resins can be optimized for various applications by controlling the content of low molecular weight components according to the required properties. To achieve this, a technology for fractionating low molecular weight components from high molecular weight components is necessary. Regarding techniques related to fractionation, for example, the following patent documents 1 and 2 are known. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 02-060915 [Patent Document 2] Japanese Patent Publication No. 2008-050513 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Patent Document 1 discloses a method for removing low-nuclear bodies from a novolac resin by adding a water-soluble alcohol and water to a resin solution in which the novolac resin is dissolved, thereby removing low-nuclear bodies from the resin solution. Patent Document 2 discloses a method for producing a novolac-type phenolic resin, comprising the steps of (b) removing low-nuclear bodies from a novolac-type phenolic resin by solvent fractionation using a poor solvent and a good solvent for the resin, and (c) removing low-nuclear body components of the novolac-type phenolic resin by adding a low-boiling-point compound with a boiling point lower than the reaction system temperature while maintaining the reaction system temperature at 170-250°C. However, all of these technologies essentially require the use of large amounts of methanol. Specifically, as shown in the examples of Patent Document 1, methanol is required as a water-soluble alcohol, and the amount used is large, at 200 to 240 parts by mass per 500 to 600 parts by mass of resin solution. Also, as shown in the examples of Patent Document 2, methanol or acetone is required as a poor solvent, and the amount used is large, at 900 to 1500 parts by mass per 1450 to 1653 parts by mass of resin solution. Both methanol and acetone, as mentioned above, are highly volatile compounds with relatively high physicochemical hazards and health risks. Therefore, their use tends to be difficult, requiring high costs for equipment and work environments.

[0005] This invention has been made in view of the above circumstances, and aims to provide a method for fractionating phenolic resin using a more easily handled solvent, a method for producing phenolic resin, and a solvent for fractionating phenolic resin. [Means for solving the problem]

[0006] In other words, the present invention is as follows. [1] The resin solution obtained by dissolving a phenol resin in solvent A and solvent B are mixed, and the extraction step is performed to extract the low molecular weight components of the phenol resin into solvent B. Solvent component A that constitutes the aforementioned solvent A N The weighted average of SP values ​​using the Fedors method is calculated as SPA and the solvent component B constituting the solvent B N the weighted average of the SP value by the Fedors method is SP B when A method for fractionating a phenolic resin, characterized by satisfying the following (1) and (2). (1) SP A ≤ 9.5 (2) 14.0 ≤ SP B ≤ 20.5 [2] The method for fractionating a phenolic resin according to [1] above, wherein the phase obtained by extracting the low molecular weight component into the solvent B constitutes the lower phase. [3] The weighted average of the specific gravity of the solvent component A N is D A and the weighted average of the specific gravity of the solvent component B N is D B when, the method for fractionating a phenolic resin according to [1] or [2] above, which satisfies the following (3). (3) D B - D A ≥ 0.2 [4] The method for fractionating a phenolic resin according to any one of [1] to [3] above, wherein the vapor pressure of the solvent component B at 25 °C is 1000 Pa or less. N at 25 °C is 1000 Pa or less. [5] When the total mass of the phenolic resin is M P and the total mass of the solvent A is M A then, 0.5 ≤ M A / M P ≤ 3. The method for fractionating a phenolic resin according to any one of [1] to [4] above. [6] When the total mass of the solvent A is M A and the total mass of the solvent B is M B then, M B / M A gt; 1. The method for fractionating a phenolic resin according to any one of [1] to [5] above. [7] The method for fractionating a phenolic resin according to any one of [1] to [6] above, wherein the solvent component B N contains a polyhydric alcohol. [8] A method for fractionating a phenol resin according to any one of 1 to 7 above, wherein the water content in solvent B is 25% by mass or less relative to the total amount of solvent B. [9] Solvent component A N A method for fractionating a phenolic resin according to any one of the above [1] to [8], comprising one or more selected from ketones, esters, and ethers.

[10] A method for fractionating a phenolic resin according to any one of [1] to [9] above, wherein the phenolic resin is of the novolac type.

[11] A method for producing a phenol resin, characterized by comprising the fractionation method of the phenol resin described in [1] to

[10] above.

[12] A solvent for fractionating phenol resin, used in a fractionation method in which a resin solution obtained by dissolving a phenol resin in solvent A is mixed with solvent B, and the low molecular weight components of the phenol resin are extracted into solvent B, The solvent A is composed of solvent component A N Weighted average SP values ​​using the Fedors method A SP A It is a solvent with a pH of ≤9.5. The solvent B is the solvent component B that constitutes the solvent B. N Weighted average SP values ​​using the Fedors method B 14.0≦SP B A solvent for fractionating phenolic resins, characterized by being a solvent with a solvent content of ≤20.5. [Effects of the Invention]

[0007] According to the phenol resin fractionation method of the present invention, a solvent that is easier to handle than conventional methods can be used, making it possible to design the apparatus for fractionating phenol resin and the working environment for that purpose at a lower cost. According to the present invention's method for producing phenolic resin, a solvent that is easier to handle than conventional methods can be used, allowing for the design of equipment and working environment for producing phenolic resin at a lower cost. The solvent for phenol resin fractionation of the present invention allows for the use of a solvent that is easier to handle than conventional solvents, thus enabling the design of equipment for fractionating phenol resin and manufacturing phenol resin, as well as the working environment therefor, at a lower cost. [Brief explanation of the drawing]

[0008] [Figure 1] This is an explanatory diagram illustrating the process of extracting the lower phase. [Figure 2] This is an explanatory diagram illustrating the process of extracting the extracted phase as the upper phase. [Modes for carrying out the invention]

[0009] The present invention will now be described. The matters described herein are illustrative and illustrative to illustrate embodiments of the present invention, and are intended to provide what is considered to be the most effective and readily understandable explanation of the principles and conceptual features of the present invention. In this regard, it is not intended to describe the constituent details of the present invention beyond what is necessary for a fundamental understanding of the invention, and this description will make it clear to those skilled in the art how some forms of the present invention are actually embodied.

[0010] [1] Method for fractionating phenolic resin The present invention provides a method for fractionating phenolic resin (hereinafter also simply referred to as "this fractionation method"), which includes an extraction step of mixing a resin solution obtained by dissolving phenolic resin in solvent A with solvent B, and extracting the low molecular weight components of the phenolic resin into solvent B. Solvent component A that constitutes the aforementioned solvent A N The weighted average of SP values ​​using the Fedors method is calculated as SP A year, Solvent component B that constitutes the solvent B N The weighted average of SP values ​​using the Fedors method is calculated as SP B In that case, It is characterized by satisfying the following conditions (1) and (2). (1) SP A ≤9.5 (2) 14.0 ≤ SP B ≤20.5

[0011] <1> Phenolic resin Phenolic resins are condensation products obtained by reacting a phenol compound with an aldehyde compound in the presence of a catalyst. Of these, those obtained using an acidic catalyst are novolac-type phenolic resins, and those obtained using a basic catalyst are resol-type phenolic resins. Phenolic resins obtained using other catalysts, such as divalent metal salts, are also included in the above-mentioned phenolic resins. These phenolic resins may be in liquid form (including varnishes and emulsions, etc.), solid form, or mixtures thereof. Furthermore, the phenolic resin may be of the novolac type only, the resol type only, or a combination of both. The phenolic resin fractionation method of the present invention is more useful when the phenolic resin is of the novolac type. That is, it is preferable for the phenolic resin to contain the novolac type, and more preferably for phenolic resins consisting solely of the novolac type.

[0012] <1-1> Phenolic compounds Phenol compounds include phenols and their derivatives, as well as other phenols. These may be used individually or in combination of two or more. Among these, phenols are compounds having an aromatic ring and a phenolic hydroxyl group, and include, for example, phenols such as phenol, naphthols such as α-naphthol and β-naphthol, antrols, and hydroxypyrene (monovalent phenols); and polyvalent phenols such as resorcinol, hydroquinone, catechol, pyrogallol, and phloroglucin. The number of phenolic hydroxyl groups in a polyvalent phenol is not limited, but can be, for example, 2 to 3. These may be used individually or in combination of two or more.

[0013] Furthermore, derivatives of phenols include, for example, derivatives of monovalent phenols and derivatives of polyvalent phenols. More specifically, alkyl derivatives are examples of each. These may be used individually or in combination of two or more. The alkyl group constituting the alkyl derivative is not limited, but for example, it can have 1 to 10 carbon atoms. Furthermore, it may have only one alkyl group, or two or more; for example, it may have 1 to 3 alkyl groups. More specifically, alkyl derivatives of monovalent phenols include cresols such as o-cresol, m-cresol, and p-cresol; xylenols such as 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol; ethylphenols such as o-ethylphenol, m-ethylphenol, and p-ethylphenol; propylphenols such as isopropylphenol; butylphenols such as p-tert-butylphenol; nonylphenol; and trialkylphenols such as trimethylphenol. These may be used individually or in combination of two or more. Examples of alkyl derivatives of polyhydric phenols include alkylresorcinol, alkylcatechol, and alkylhydroquinone. These may be used individually or in combination of two or more.

[0014] Other phenols include bisphenols, biphenols, trisphenols, and tetraphenols. These may be used individually or in combination of two or more. Among these, bisphenols include various types of bisphenols such as bisphenol A, bisphenol F, bisphenol S, bisphenol M, bisphenol B, bisphenol C, and bisphenol S. These may be used individually or in combination of two or more types.

[0015] <1-2> Aldehyde compounds Aldehyde compounds are compounds having an -CHO structure. These may be used individually or in combination of two or more. The type of aldehyde compound is not limited, but examples include aliphatic aldehydes and aromatic aldehydes. These may be used individually or in combination of two or more.

[0016] Among the above, aliphatic aldehydes include formaldehyde, paraformaldehyde, polyoxymethylene, trioxane, tetraoxymethylene, glyoxal, acetaldehyde, paraaldehyde, propionaldehyde, propenaldehyde, butanal, hexanal, malondialdehyde, succinidaldehyde, glutardialdehyde, allylaldehyde, crotonaldehyde, and chloral. These can also be used as various solutions, such as formalin, which is an aqueous solution of formaldehyde. Furthermore, aldehyde-producing compounds such as hexamethylenetetramine, which produce aldehyde compounds by decomposition, can be used. These can be used individually or in combination of two or more.

[0017] Among the above, examples of aromatic aldehydes include furfural, benzaldehyde, phenylacetaldehyde, tolaldehyde (o-tolaldehyde, m-tolaldehyde, p-tolaldehyde), salicylaldehyde, naphthaldehyde, terephthalaldehyde, phenylbenzaldehyde, and hydroxybenzaldehyde. These may be used individually or in combination of two or more.

[0018] <1-3> Catalyst As mentioned above, examples of catalysts include acidic catalysts, basic catalysts, and other catalysts. Examples of acidic catalysts among those listed above include hydrochloric acid, sulfuric acid, phosphoric acid (including polyphosphates such as metaphosphoric acid, pyrophosphoric acid, orthophosphoric acid, triphosphoric acid, tetraphosphoric acid, and phosphoric anhydride), phosphorous acid, phosphonic acid, and other inorganic acids; oxalic acid, diethyl sulfate and other sulfuric acid esters, organic sulfonic acids, and organic phosphones. These may be used individually or in combination of two or more. Furthermore, examples of organic sulfonic acids among the above include p-toluenesulfonic acid, benzenesulfonic acid, and xylenesulfonic acid. In addition, examples of organic phosphonic acids include ethylenediaminetetrakismethylenephosphonic acid, ethylenediaminebismethylenephosphonic acid, aminotrismethylenephosphonic acid, β-aminoethylphosphonic acid N,N-diacetic acid, aminomethylphosphonic acid N,N-diacetic acid, 1-hydroxyethylidene-1,1'-diphosphonic acid, and 2-phosphonobutane-1,2,4-tricarboxylic acid.

[0019] Examples of basic catalysts among those mentioned above include metal hydroxides, metal oxides, and amine compounds. These may be used individually or in combination of two or more. Examples of metal hydroxides include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; and alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide. Examples of metal oxides include alkaline earth metal oxides such as calcium oxide and magnesium oxide. Furthermore, examples of amine compounds include aliphatic amines such as dimethylamine, triethylamine, and butylamine; and aromatic amines such as dimethylbenzylamine and naphthalenediamine. These may be used individually or in combination of two or more. Furthermore, examples include ammonia, ammonia-producing compounds such as hexamethylenetetramine that produce ammonia upon decomposition, and naphthenates. These may be used individually or in combination of two or more.

[0020] Other catalysts include metal compounds not listed above. For example, divalent metal salts and divalent metal compounds such as zinc oxide, zinc chloride, and zinc acetate are examples. These may be used individually or in combination of two or more.

[0021] <1-4> Reaction solvent The reaction conditions between phenol compounds and aldehyde compounds are not limited, and known conditions can be applied. Furthermore, a reaction solvent can be used as needed during the reaction. Examples of reaction solvents include ketone compounds, ester compounds, alcohol compounds, and ether compounds. These may be used individually or in combination of two or more.

[0022] Among the above, examples of ketone compounds include methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone, ethyl n-butyl ketone, diisopropyl ketone, diethyl ketone, di-n-propyl ketone, mesityl oxide, methyl n-amyl ketone, methyl n-butyl ketone, methyl n-propyl ketone, and acetone. These may be used individually or in combination of two or more.

[0023] Among the above, examples of ester compounds include methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, n-butyl acetate, sec-butyl acetate, isobutyl acetate, ethoxyethyl acetate, oxyethyl acetate, amyl acetate, isoamyl acetate, allyl acetate, ethyl isovalerate, propyl formate, butyl formate, isobutyl formate, isoamyl formate, diethyl carbonate, methyl propionate, ethyl propionate, butyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxypropionate, isopropyl butyrate, ethyl butyrate, methyl butyrate, γ-butyrolactone, ethyl lactate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl acetoacetate, ethyl acetoethyl acetate, etc. These may be used individually or in combination of two or more.

[0024] Among the above, examples of alcohol compounds include amyl alcohol (n-amyl alcohol, s-amyl alcohol, t-amyl alcohol), isoamyl alcohol, 2-ethylbutanol, 3,5-dimethyl-1-hexyne 3-ol, neopentyl alcohol, 2-methyl-1-butanol, 4-methyl-2-pentanol, ethylene glycol monoalkyl ethers (ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, etc.), diethylene glycol monobutyl ether, etc.), diethylene glycol dialkyl ethers (diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, etc.), and propylene glycol monoalkyl ethers (propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, etc.). These may be used individually or in combination of two or more.

[0025] Among the above, ether compounds include diethyl ether, ethyl isoamyl ether, ethyl-t-butyl ether, 1,2-epoxybutane, diisopropyl ether, diethyl acetal, dibutyl ether, 2-methylfuran, ethylene glycol monoalkyl ether (ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, etc.), ethylene glycol dialkyl ether (ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, etc.), diethylene glycol monoalkyl ether (diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, etc.), diethylene glycol dialkyl ether (diethylene glycol dimethyl ether, diethylene Examples include propylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, etc., ethylene glycol alkyl ether acetate (methyl cellosolve acetate, ethyl cellosolve acetate, etc.), propylene glycol monoalkyl ether (propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, etc.), propylene glycol dialkyl ether (propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, etc.), propylene glycol alkyl ether acetate (propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, etc.), and cyclic ethers (tetrahydrofuran, dioxane, etc.). These may be used individually or in combination of two or more.

[0026] <1-5> Combination The mixing ratio F / P (molar ratio) of the phenol compound (P) to the aldehyde compound (F) when obtaining a phenol resin is not limited, but from the viewpoint of obtaining a novolac-type phenol resin using an acidic catalyst, it is preferable that F / P ≤ 1, and more preferably 0.55 ≤ F / P ≤ 0.80. Also, from the viewpoint of obtaining a resol-type phenol resin using a basic catalyst, it is preferable that F / P ≥ 1, and more preferably 1.1 ≤ F / P ≤ 4.0.

[0027] <2> Solvent A Solvent A is a solvent capable of dissolving phenolic resin to form a resin solution. The phenolic resin may be completely dissolved in solvent A, or only partially dissolved. Therefore, the resin solution may be a solution in which the phenolic resin is completely dissolved, or it may be an emulsion, suspension, or the like. Furthermore, solvent A may consist of only one compound, or it may consist of two or more compounds. That is, solvent A may consist of one solvent component, or it may consist of two or more solvent components. When it consists of two or more solvent components, these solvent components usually need to be miscible, and more preferably, they should also be miscible.

[0028] And solvent A is composed of solvent component A N SP value by Fedors method [unit (cal / cm 3 ) 1 / 2 The weighted average of ] is SP A [Unit (cal / cm) 3 ) 1 / 2 If ] then SP A These are solvents with a coefficient of ≤9.5. Therefore, for example, if the resin liquid already contains the reaction solvent described above, the reaction solvent is considered to be solvent A, and its SP A SP A If the value is ≤9.5, this resin solution can be used directly as the resin solution for fractionation. Furthermore, the reaction solvent is considered to be solvent A, and its SP A SP AIf >9.5, then SP A SP A By adding a solvent with a smaller SP value such that the SP value is ≤9.5, a resin solution for fractionation can be formed. Furthermore, if the phenolic resin is present separately from the solvent, the phenolic resin can be mixed with one or more solvents to form a resin solution for fractionation.

[0029] Solvent component A N The aforementioned reaction solvent can be used. However, SP A SP A Since it must be ≤9.5, one solvent component A N SP value by Fedors method (SP AN ) is SP AN >9.5 is also acceptable, SP AN It is preferable that the value is ≤9.5. Thus, SP AN Solvent component A is ≤9.5 N The following compounds are examples of the reaction solvents mentioned above. Note that when using only one of the compounds listed below, the following SPs are used. AN SP AN =SP A That is the case.

[0030] Solvent component A N Examples of ketone compounds that can be used include methyl isobutyl ketone (SP AN =8.68), methyl ethyl ketone (SP AN =8.98), (ethyl n-butyl ketone (SP AN =9.21), diisopropyl ketone (SP AN =8.49), diethyl ketone (SP AN =8.92), di-n-propyl ketone (SP AN =8.84), Mesityl oxide (SP AN =8.96), methyl n-amyl ketone (SP AN =8.84), methyl n-butyl ketone (SP AN =8.88), methyl n-propyl ketone (SPAN = 8.92), acetone (SP AN = 9.07), etc. These may be used alone or in combination of two or more kinds.

[0031] Solvent component A N As the ester compound that can be used as, ethyl acetate (SP AN = 8.74), propyl acetate (SP AN = 8.72), isopropyl acetate (SP AN = 8.50), n-butyl acetate (SP AN [[ID=IS]]= 8.70), sec-butyl acetate (SP AN = 8.51), isobutyl acetate (SP AN = 8.51), amyl acetate (SP AN = 8.23), isoamyl acetate (SP AN = 8.52), allyl acetate (SP AN = 8.89), ethyl isovalerate (SP AN = I 8.52), diethyl carbonate (SP AN = 8.53), methyl propionate (SP AN = 8.74), ethyl propionate (SP AN = 8.72), butyl propionate (SP AN = 8.69), methyl 3-methoxypropionate (SP AN = 9.39), methyl butyrate (SP AN = 8.66), ethyl butyrate (SP AN = 8.70), isopropyl butyrate (SP AN = 8.52), etc. These may be used alone or in combination of two or more kinds.

[0032] Solvent component A N As the ether compound that can be used as, diethyl ether (SP AN = 7.25), ethyl isoamyl ether (SP AN = 7.50), ethyl-t-butyl ether (SP AN = 7.12), 1,2-epoxybutane (SP AN = 8.63), diisopropyl ether (SP AN = 7.15), diethyl acetal (SPAN =7.65), 2-methylfuran (SP AN =9.14), ethylene glycol diethyl ether (SP AN =7.85), Propylene glycol monomethyl ether acetate (SP AN =9.12), tetrahydrofuran (SP AN Examples include (=8.28). These may be used individually or in combination of two or more.

[0033] The above SP A SP A ≤9.5 is acceptable, but furthermore, SP A ≤9.2 is preferred, SP A ≤9.0 is more preferable, SP A ≤8.9 is even more preferable, SP A ≤8.8 is particularly preferable. SP A The lower limit is not limited, but usually, SP A ≥7.0, SP A ≥7.5 is preferable, SP A ≥8.0 is more preferable, SP A ≥8.3 is even more preferable, SP A ≥8.5 is particularly preferable. These SP A The upper and lower limits for SP can be combined in any way, but 7.0 ≤ SP A ≤9.2 is preferred, and 7.5 ≤SP A ≤9.0 is more preferable, and 8.0 ≤SP A ≤8.9 is even more preferable, and 8.5 ≤SP A A range of ≤8.8 is particularly preferred. Within this range, the high molecular weight components of the phenol resin are easily dissolved by solvent A, and the solvent components A that make up solvent A N And, solvent component B that constitutes solvent B N This allows for a combination that is difficult to mix.

[0034] Furthermore, as mentioned above, SP AN SP AN It is preferable that SP be ≤9.5, AN ≤9.2 is more preferable, SP AN ≤9.0 is even more preferable, SP AN≤8.9 is particularly preferred, SP AN ≤8.8 is particularly preferable. AN The lower limit is not limited, but usually, SP AN ≥7.0, SP AN ≥7.5 is preferable, SP AN ≥8.0 is more preferable, SP AN ≥8.3 is even more preferable, SP AN ≥8.5 is particularly preferable. These SP AN The upper and lower limits for SP can be combined in any way, but 7.0 ≤ SP AN ≤9.2 is preferred, and 7.5 ≤SP AN ≤9.0 is more preferable, and 8.0 ≤SP AN ≤8.9 is even more preferable, and 8.5 ≤SP AN A range of ≤8.8 is particularly preferred. Within this range, the high molecular weight components of the phenol resin are easily dissolved by solvent A, and the solvent components A that make up solvent A N And, solvent component B that constitutes solvent B N This allows for a combination that is difficult to mix.

[0035] Note that solvent component A N The SP value obtained by the Fedors method is the value calculated by the Fedors method (Robert F. Fedors, Polymer Engineering and Science, 14[2], 147-154 (1974), "A method for estimating both the solubility parameters and molar volumes of liquids"), and is "δ" as shown in equation (1) below. δ = (E / V) 1 / 2 ... (1) In equation (1), δ is the SP value, E is the cohesive energy (cal / mol), and V is the molar molecular volume (cm³). 3 Each value represents ( / mol). Furthermore, each E and V value is based on Table 5 disclosed on page 152 of the above-mentioned document.

[0036] Furthermore, as mentioned above, SP A This is solvent component A NThis is a weighted average of SP values ​​by the Fedors method, and solvent component A N This is a weighted average based on the mass ratio of the two solvent components A1 and A2. N Composed of the above, and with a mass ratio of solvent component A1 and solvent component A2 of R1:R2, and R1+R2=1, SP A =(SP A1 ×R1)+(SP A2 This indicates that ×R²). Similarly, solvent component A that constitutes solvent A. N If there are three or more types, the above applies to SP. A =(SP A1 ×R1)+(SP A2 ×R2)+(SP A3 It is calculated as ×R3)+····. Furthermore, if solvent A consists of only one solvent component A1, then naturally the SP value of solvent component A1 (SP A1 ) is the SP value of solvent A (SP A ) This is also true for solvent B, and the above A can be replaced with B.

[0037] Note that solvent component A N SP AN If a solvent component with a pH of >9.5 is included, its content is not limited, but it is preferably 60% by mass or less, more preferably 40% by mass or less, even more preferably 25% by mass or less, particularly preferably 15% by mass or less, and especially preferably 5% by mass or less (greater than 0% by mass) relative to the total amount of solvent A (100% by mass).

[0038] <3> Solvent B Solvent B is a solvent that, when mixed with a resin solution obtained by dissolving phenol resin in solvent A, can extract the low molecular weight components of the phenol resin. Furthermore, solvent B may consist of only one compound, or it may consist of two or more compounds. That is, solvent B may consist of one solvent component, or it may consist of two or more solvent components. When it consists of two or more solvent components, these solvent components usually need to be miscible, and more preferably, they should be miscible. On the other hand, solvent component A that constitutes solvent A N And, solvent component B that constitutes solvent B N It is preferable that the combination of these elements is not miscible.

[0039] And solvent B is composed of solvent component B N SP value by Fedors method [unit (cal / cm 3 ) 1 / 2 The weighted average of ] is SP B [Unit (cal / cm) 3 ) 1 / 2 If ] then 14.0≦SP B These are solvents with a coefficient of ≤20.5. Since the SP value of the reaction solvents described above, calculated by the Fedors method, is usually less than 14, it is generally difficult to satisfy the condition of being solvent B while using the reaction solvents described above as the main component. Therefore, solvent B is usually different from the reaction solvents described above.

[0040] Solvent component B N SP value (SP BN ) is not limited, SP B 14.0≦SP B Since it must be ≤20.5, one solvent component B N SP value by Fedors method (SP BN ) is 14.0>SP BN or SP BN >20.5 is also acceptable, but 14.0 ≤ SP BN It is preferable that the value be ≤20.5. Of the above, solvent component B N 14.0>SP available as BN or SP BN Compounds with a value of >20.5 include water (SP BN =26.68), methanol (SPBN =13.77), triethylene glycol (SP BN =13.58), 1,3-propanediol (SP BN =13.52), dipropylene glycol (SP BN =11.30, 13.55, 13.41 (3 isomers), 1,1-pentanediol (SP BN =13.99), 1,2-pentanediol (SP BN Examples include (=13.99). These may be used individually or in combination of two or more. However, solvent component B N 14.0>SP available as B or SP B Compounds with a concentration of >20.5 are compounds that, on their own, cannot form solvent B.

[0041] On the other hand, among the above, solvent component B N 14.0≦SP can be used as B Compounds with a ≤20.5 include ethylene glycol (SP BN =17.83), propylene glycol (SP BN =15.91), 1,3-butanediol (SP BN =14.80), 1,4-butanediol (SP BN =14.99), 2,3-butanediol (SP BN =14.60), 1,2-butanediol (SP BN Dihydric alcohols such as (=14.80) and glycerin (SP BN Trihydric alcohols such as (=20.02), diethylene glycol (SP BN Examples include polyhydric alcohols such as (=14.97). These may be used individually or in combination of two or more. Furthermore, when using only one of the compounds listed above, the following SPs are used. BN SP BN =SP B That is the case.

[0042] Solvent component B N Among the above compounds, polyhydric alcohols are preferred. That is, solvent B is solvent component BN It is preferable that it contains polyhydric alcohols. Polyhydric alcohols are generally not very volatile and do not require excessively confined workspaces. Therefore, they enable low-cost operation, are environmentally friendly, and offer significant benefits to workers. Furthermore, polyhydric alcohols are miscible with water, and some combinations exhibit particularly good miscibility. This allows for the cleaning of fractionation equipment with water, which again contributes to low-cost operation, environmental friendliness, and significant benefits to workers.

[0043] The above SP B 14.0≦SP B It is acceptable if it is ≤20.5, but furthermore, SP B ≤20.0 is preferred, SP B ≤19.0 is more preferable, SP B ≤18.5 is even more preferable, SP B A value of ≤18.0 is particularly preferable. SP B The lower limit is SP B ≥14.5 is preferable, SP B ≥15.0 is more preferable, SP B ≥16.0 is even more preferable, SP B ≥17.0 is particularly preferable. These SP B The upper and lower limits for SP can be combined in any way, but 14.5 ≤ SP B ≤20.5 is preferred, and 15.0 ≤SP B ≤20.0 is more preferable, and 16.0 ≤SP B ≤19.0 is even more preferable, and 17.0 ≤SP B A range of ≤18.5 is particularly preferred. Within this range, the low molecular weight components of the phenol resin are easily extracted by solvent B, and the solvent components A that make up solvent A are also present. N And, solvent component B that constitutes solvent B N This allows for a combination that is difficult to mix. Furthermore, as mentioned above, solvent component B N The SP value according to the Fedors method, and furthermore, SP B This is solvent component A N SP values ​​obtained by the Fedors method, and SP A It is defined similarly.

[0044] Furthermore, as mentioned above, SP BN 14.0≦SP BN It is preferable that SP be ≤20.5, BN ≤20.0 is more preferable, SP BN ≤19.0 is even more preferable, SP BN ≤18.5 is particularly preferred, SP BN ≤18.0 is particularly preferable. SP BN The lower limit is SP BN ≥14.5 is preferable, SP BN ≥15.0 is more preferable, SP BN ≥16.0 is even more preferable, SP BN ≥17.0 is particularly preferable. These SP BN The upper and lower limits for SP can be combined in any way, but 14.5 ≤ SP BN ≤20.5 is preferred, and 15.0 ≤SP B ≤20.0 is more preferable, and 16.0 ≤SP B ≤19.0 is even more preferable, and 17.0 ≤SP B A range of ≤18.5 is particularly preferred. Within this range, the low molecular weight components of the phenol resin are easily extracted by solvent B, and the solvent components A that make up solvent A are also present. N And, solvent component B that constitutes solvent B N This allows for a combination that is difficult to mix.

[0045] Note that solvent component B N As such, 14.0>SP BN or SP BN If a solvent component with a concentration of >20.5 is included, its content is not limited, but it is preferably 60% by mass or less, more preferably 40% by mass or less, even more preferably 25% by mass or less, particularly preferably 15% by mass or less, and especially preferably 5% by mass or less (greater than 0% by mass) relative to the total solvent B (100% by mass).

[0046] Also, solvent component B NWhile solvent components with a vapor pressure exceeding 1000 Pa at 25°C (i.e., high vapor pressure solvent components) may be used, it is preferable to use solvent components with a vapor pressure of 1000 Pa or less at 25°C (i.e., low vapor pressure solvent components). This suppresses the volatilization of solvent B, allowing for safer maintenance of the apparatus and working environment for phenol resin fractionation. Furthermore, it allows for the construction of the apparatus and working environment for phenol resin fractionation at a lower cost. More specifically, for example, by using low vapor pressure solvent components, when opening the flow control device (valve, etc.) of the apparatus (manufacturing plant, etc.) for phenol resin fractionation, it is possible to suppress phenomena such as a sudden change in the flow velocity of the material (for example, the contents of the apparatus suddenly spraying out). In other words, the safety of the apparatus and working environment can be enhanced.

[0047] The vapor pressure of the low vapor pressure solvent component should be 1000 Pa or less, but can be, for example, 750 Pa or less, even 500 Pa or less, and especially 100 Pa or less. By using a low vapor pressure solvent component, the apparatus and working environment for fractionating phenolic resins can be maintained more safely. In addition, the apparatus and working environment for fractionating phenolic resins can be constructed at a lower cost. The lower limit of the vapor pressure is not limited, but for example, it should be 0.01 Pa or more, and can be 0.5 Pa or more. Specifically, solvent component B as described above. N Among these, compounds that can form solvent B on their own (14.0 ≤ SP B The compounds in the ≤20.5 range all have a vapor pressure of 0.5 to 100 Pa at 25°C. For example, the vapor pressure of ethylene glycol at 25°C is 12.27 Pa, propylene glycol at 25°C is 17.33 Pa, glycerin at 25°C is 10 Pa, and diethylene glycol at 25°C is 0.76 Pa. Note that solvent component B N The vapor pressure can be measured in accordance with ISO 3007:1999. However, the measurement temperature will be changed.

[0048] <4> Correlation between solvent A and solvent B Solvents A and B are not limited to having SP values ​​in different bands, as mentioned above, but furthermore, solvent component A N D is the weighted average of the specific gravities. A And solvent component B N D is the weighted average of the specific gravities. B In that case, D B >D A It is preferable that this is the case. D B >D A In this case, during the extraction process, the phase in which the low molecular weight components have been extracted into solvent B (hereinafter also simply called the "extraction phase") can be used as the lower phase. When the extraction phase is the lower phase in this way, the extraction phase can be removed from the bottom of the container (extraction tank).

[0049] Generally, the extracted phase is the upper phase 21. Therefore, conventionally, a suction tube 15 is inserted from the top of the container 10, and the upper phase (extracted phase) is removed by suction (see Figure 2). In contrast, when the extracted phase is to be removed as the lower phase 22, an outflow tube 11 (and furthermore, a stopcock 12) can be provided below the container 10, allowing the lower phase 22 to be removed by gravity (see Figure 1). In other words, it becomes unnecessary to insert the suction tube 15 from the top of the container 10. However, this operation using the suction tube 15 has disadvantages.

[0050] For example, when extracting the upper phase 21, if the lower phase 22 remaining in the container 10 is the target substance, the lower phase 22 remaining in the container 10 must be transferred to another container before the next step can be performed. Therefore, in effect, a container for storing the lower phase 22 is required for fractionation. In addition, a step of returning the lower phase 22 to the container 10 is required. On the other hand, when extracting the lower phase 22, as described above, the lower phase 22 can be extracted by allowing it to fall under its own weight by providing an outlet pipe 11, etc. Therefore, a container for storing the upper phase 21 is not required. In other words, fractionation can be achieved in a smaller space and with fewer steps.

[0051] Furthermore, when extracting the upper phase 21, the extraction process must be carried out by visually observing from above and identifying the interface between the upper phase 21 and the lower phase 22. However, identifying this interface is difficult. In contrast, when extracting the lower phase 22, as described above, the lower phase can be gradually extracted by allowing it to fall under its own weight, for example, by providing an outflow pipe 11 below the container 10. In this case, the outflow of components constituting the interface can be visually confirmed when the lower phase 22 has completely flowed out, making it easy to identify the interface. Therefore, it is possible to prevent the residue of low molecular weight components within high molecular weight components, and to prevent excessive extraction of high molecular weight components along with low molecular weight components.

[0052] Furthermore, when extracting the upper phase 21, as described above, the suction tube 15 is inserted from above the container 10. However, since this suction tube 15 remains in contact with the upper phase 21, upper phase components may adhere to the periphery of the suction tube 15. Consequently, these adhering components may be introduced into the lower phase 22 as contaminants. In contrast, when extracting the lower phase 22, insertion of the suction tube 15 is not required. Therefore, the possibility of contaminants entering the upper phase 21 can be almost completely eliminated.

[0053] As mentioned above, solvent component A N Weighted average specific gravity D A And solvent component B N Weighted average specific gravity D B And, to D B >D A It is preferable to do so, but the weighted average specific gravity D A and weighted average specific gravity D B This is as follows: That is, for example, solvent A has a specific gravity D A1 The solvent component A1 and the specific gravity D A2 Two types of solvent components A2 and N If the composition is such that the mass ratio of solvent component A1 and solvent component A2 is R1:R2 and R1+R2=1, then D A =(D A1 ×R1)+(D A2 ×R²) Similarly, solvent component A that constitutes solvent A NIf there are three or more types, then the above applies to D A =(D A1 ×R1)+(D A2 ×R²)+(D A3 It is calculated as ×R3)+····. Furthermore, if solvent A consists of only one solvent component A1, then naturally the specific gravity of solvent component A1 (D A1 ) is the specific gravity of solvent A (D A ) This is also true for solvent B, and the above A can be replaced with B.

[0054] And the weighted average specific gravity D A and weighted average specific gravity D B That is D B >D A It is preferable, but furthermore, D A <1.0 and D B It is more preferable to satisfy ≥1.0. Also, D A D A ≤0.95 is more preferable, D A ≤0.90 is even more preferable. On the other hand, D B D B ≥1.03 is more preferable, D B ≥1.05 is even more preferable. Furthermore, D B -D A It is particularly preferable to satisfy the condition ≥ 0.2. This ensures that the extraction phase containing high molecular weight components is positioned in the upper phase and the extraction phase containing low molecular weight components is positioned in the lower phase.

[0055] As mentioned above, high molecular weight components dissolve in solvent A. This increases the specific gravity of the entire extracted phase in solvent A. On the other hand, low molecular weight components have a lower specific gravity compared to high molecular weight components, and their dissolution amount is also smaller compared to solvent A, so the actual increase in specific gravity is relatively negligible. In the fractionation of phenolic resins, the increase in specific gravity due to the dissolution of high molecular weight components in solvent A is usually less than 0.2, but for example, D B -D AWhen the specific gravity is ≥0.3, it is possible to allow a specific gravity increase of less than 0.3 while positioning the extracted phase of low molecular weight components in the lower phase. For example, if the specific gravity of the phenol resin is estimated to be 1.2, the specific gravity of the low molecular weight components to be fractionated can be estimated to be between 1.0 and less than 1.2. Furthermore, the low molecular weight components contained in the crude phenol resin will be, for example, 30% or less (even 25% or less, and even 15% or less). Therefore, as shown in Comparative Examples 3 to 4 described later, it is possible to fractionate the phenol resin using methanol, for example, but because of its low specific gravity, it is difficult to extract the low molecular weight components to the lower phase. In contrast, as shown in Examples 1 to 11, by using a polyhydric alcohol as the solvent component of solvent B, the use of methanol can be eliminated, and the low molecular weight components can be extracted to the lower phase.

[0056] In particular, solvent component B N Specific gravity D BN D is alone BN It is preferable that the solvent component B is >1.00. N It is preferable that the specific gravity of the element alone is greater than 1.00. This allows for the above-mentioned 14.0 ≤ SP B While achieving ≤20.5, solvent component B N This makes it easier to use polyhydric alcohols. As mentioned above, the use of polyhydric alcohols offers many advantages. In this specification, the specific gravity of the solvent (solvent component) is defined as the value measured using a specific gravity bottle at 25°C, in accordance with JIS Z8804:2012.

[0057] Also, solvent component B N If a polyhydric alcohol can be used as the solvent component B N As such, water can be used simultaneously. Water and polyhydric alcohols are miscible, and in particular, there are combinations that are miscible. Furthermore, as mentioned above, the SP value of water is large at 26.68, so by using water as solvent component B, the overall SP value of solvent B (SP B ) can be adjusted more significantly. And SP BSolvent B has a large SP B When comparing solvent B, which has a small SP, B Solvent B, which has a large SP, B Compared to solvent B, which has a small SP value, it becomes more difficult to uniformly extract components from low to high molecular weight, but this can improve the yield. Therefore, it is useful when yield is prioritized over fractionation rate. In some systems, only low molecular weight components may be removed, so if you want to adjust the yield by adjusting the fractionation rate, adding water is one useful technique. Furthermore, adding water can increase the difference in SP values ​​between solvent A and solvent B, which can improve phase separation.

[0058] Solvent B does not necessarily have to contain water, but it can contain it. That is, solvent component B N Water is not required to be used, but it can be used. Solvent component B N When water is used, the percentage of water content is not limited, but for example, it can be 60% by mass or less relative to the total amount of solvent B (100% by mass), further reduced to 40% by mass or less, further reduced to 25% by mass or less, further reduced to 15% by mass or less, and further reduced to 5% by mass or less (greater than 0% by mass).

[0059] Furthermore, in this fractionation method, the ratio of phenol resin to solvent A and solvent B is not limited, but for example, if the total mass of the phenol resin is M P Let M be the total mass of solvent A. A In that case, 0.5 ≤ M A / M P It can be used in a ratio of ≤3. By setting the blending ratio of phenolic resin to solvent A within the above range, the phenolic resin becomes easier to dissolve in solvent A, making it easier to extract low molecular weight components into solvent B, and tending to increase the yield in a single production run. This blending ratio can be further adjusted to 0.6 ≤ M. A / M P It can be set to ≤2.5, and furthermore, 0.7 ≤ M A / M P It can be set to ≤2.0, and furthermore, 0.8 ≤ M A / M PThe range can be set to ≤1.8. Within these preferred ranges, the phenolic resin can be more easily dissolved in solvent A, the low molecular weight components can be more easily extracted into solvent B, and the yield in a single production run can be increased.

[0060] Furthermore, the mixing ratio of solvent A to solvent B is not limited, but for example, if the total mass of solvent A is M A Let M be the total mass of solvent B. B In that case, the amount of these solvents is M B / M A It can be made ≥1, but M B / M A >1 is preferable. That is, it is preferable that the mass of solvent B be greater than the mass of solvent A. There is no upper limit to this correlation, but for example, M B / M A It can be made ≤ 100, M B / M A It can be made ≤ 50, M B / M A It can be made ≤ 10, M B / M A It can be set to ≤5. On the other hand, the lower limit is 1.1 ≤ M B / M A It can be made 1.2≦M B / M A It can be made that 1.4≦M B / M A It can be made 1.7≦M B / M A These M B / M A The upper and lower limits for this can be combined in any way.

[0061] M B / M A A larger ratio can improve the extraction efficiency of low molecular weight components, but on the other hand, as the amount of solvent B used increases, the cost of fractionation increases, and especially when fractionation is performed to remove low molecular weight components, the amount of waste material increases. From this perspective, M B / M AIt is preferable to improve extraction efficiency by increasing the number of fractionation steps within a range where the coefficient becomes smaller. Specifically, 1 <M B / M A Preferably ≤10, and 1.2 ≤M B / M A ≤7 is more preferable, and 1.5 ≤ M B / M A ≤5 is more preferable, and 1.7 ≤ M B / M A A value of ≤4.5 is particularly preferable.

[0062] <5> Extraction process The extraction step of the phenol resin fractionation method of the present invention is a step of extracting low molecular weight components contained in the phenol resin into solvent B using solvent A and solvent B. In this step, only solvent A and solvent B may be used, and the extraction may be carried out in any other way. For example, since the resin solution only needs to contain solvent A and the phenol resin, if solvent B is composed of two types of solvent components B1 and solvent component B2, mixing of the resin solution and solvent B can be achieved by mixing the resin solution and solvent component B1, and then adding solvent component B2 to the resulting mixture. Furthermore, the mixing conditions, stirring conditions, and extraction time in the extraction step are not limited.

[0063] <6> Recovery process The phenol resin fractionation method of the present invention may include steps other than the extraction step. These other steps include a solvent B recovery step for recovering solvent B. The solvent B recovery step is typically performed by phase separation of a mixture of the resin liquid and solvent B mixed in a container. As described above, if solvent B becomes the lower phase after phase separation, this lower phase can be recovered. Furthermore, if necessary, the system may include a solvent A recovery step for recovering solvent A from the resin liquid from which low molecular weight components have been removed or reduced. Furthermore, while phase separation may be performed in each recovery step, it is usually done by letting it stand to separate the phase containing solvent A from the phase containing solvent B. If sufficient phase separation is not achieved at this time, (1) extend the standing time, (2) heat and / or cool, or (3) perform SP A and SPB Operations such as further increasing the difference (by adding another solvent, re-stirring, and then letting it stand again) can be performed. These operations may be performed using only one solvent or in combination of two or more solvents.

[0064] Furthermore, the extraction and recovery steps in the phenol resin fractionation method of the present invention may be performed only once, but they may also be performed two or more times. When performing the steps multiple times, it is preferable to recover the added solvent B before proceeding with the next mixing.

[0065] <7> Low molecular weight components and high molecular weight components The low molecular weight components that can be extracted by the phenol resin fractionation method of the present invention can be selected within an appropriate range depending on the solvents A and B used, as described above. For example, low molecular weight components include those with a weight-average molecular weight of 1500 or less, and it is particularly preferable to use components with a weight-average molecular weight of 1000 or less, and even more preferable to use components with a weight-average molecular weight of 800 or less. Naturally, these low molecular weight components include dimeric components, trimer components, etc. On the other hand, high molecular weight components are obtained from the extracted low molecular weight components, and for example, include those with a weight-average molecular weight exceeding 1500, and it is particularly preferable to use components with a weight-average molecular weight exceeding 1000, and even more preferable to use components with a weight-average molecular weight exceeding 800.

[0066] <8> Application of this fractionation method The phenol resin fractionation method of the present invention can be performed independently or as part of another method. That is, for example, the phenol resin fractionation method of the present invention can be used as part of a method for producing phenol resin or a method for producing epoxy resin via phenol resin. In these cases, the phenol resin fractionation method of the present invention can be performed as a fractionation step in each production method. Furthermore, the phenol resin fractionation method of the present invention can be used as part of various resist production methods. In this case as well, the phenol resin fractionation method of the present invention can be performed as a fractionation step in a resist production method.

[0067] [2] Solvents for phenolic resin fractionation The phenol resin fractionation solvent of the present invention is a phenol resin fractionation solvent used in a fractionation method in which a resin solution obtained by dissolving a phenol resin in solvent A is mixed with solvent B, and low molecular weight components of the phenol resin are extracted into solvent B. Solvent A is composed of solvent component A N Weighted average SP values ​​using the Fedors method A SP A It is a solvent with a pH of ≤9.5. Solvent B is composed of solvent component B N Weighted average SP values ​​using the Fedors method B 14.0≦SP B It is characterized by being a solvent with a viscosity of ≤20.5.

[0068] In other words, among the solvents for fractionating phenolic resins of the present invention, solvent A corresponds to the aforementioned solvent A, and the matters concerning solvent A described above can be applied as is. Also, among the solvents for fractionating phenolic resins of the present invention, solvent B corresponds to the aforementioned solvent B, and the matters concerning solvent B described above can be applied as is. Furthermore, it is preferable that solvent A and solvent B are in a two-liquid state, contained in different containers. Moreover, for example, if solvent A is a reaction solvent for phenol resin, then solution A will exist contained within the resin liquid in which the phenol resin is dissolved.

[0069] [3] Method for producing phenolic resin The present invention's method for producing phenolic resin is characterized by including the aforementioned method for fractionating phenolic resin. That is, the present invention's method for producing phenolic resin includes the aforementioned extraction step. Details of this extraction step are as described above. Furthermore, the method for producing phenolic resin according to the present invention may include, in addition to the extraction step described above, a reaction step in which a phenolic compound and an aldehyde compound are reacted in the presence of a catalyst. The phenolic compound, aldehyde compound, and catalyst that can be used in the reaction step are as described above. Furthermore, in addition to the reaction step and extraction step described above, the method for producing phenolic resin of the present invention may include, for example, a solvent B recovery step after the extraction step in which solvent B is recovered. Furthermore, if necessary, the system may include a solvent A recovery step for recovering solvent A from the resin liquid from which low molecular weight components have been removed or reduced. These processes may be performed using only one type or in combination of two or more types, as needed. [Examples]

[0070] The present invention will be described in more detail below with reference to examples, but these examples are merely illustrative examples for explanatory purposes, and the present invention is not limited in any sense to these examples.

[0071] (1) Fraction of Example 1 (1-1) 100 parts by mass of a novolac-type phenolic resin containing 22.1% by mass of low molecular weight components with a weight-average molecular weight of 800 or less (phenol compound = cresol, aldehyde component = formaldehyde, catalyst = oxalic acid, F / P ≤ 1, specific gravity 1.19 according to the liquid weighing method (balance method) of JIS Z8807:2012), which is solvent A, methyl isobutyl ketone (SP A =8.68, D A =0.80, purity 99%) 100 parts by mass and solvent B, which is ethylene glycol (SP B =17.8, D B A resin solution was obtained by dissolving 200 parts by mass of a substance with a purity of 99% (=1.11).

[0072] (1-2) After mixing and stirring the obtained resin solution, it was left to stand for 2 hours at a temperature of 40°C to separate into two phases. In the phase-separated state, the phase containing solvent B became the lower phase. The lower phase was removed by gravity from the bottom of the container, leaving the upper phase in the container. This operation was repeated two more times. In other words, a total of three extraction operations were performed.

[0073] (1-3) A novolac-type phenol resin solution was obtained from the upper phase obtained through the operation in (1-2) above, from which low molecular weight components had been removed. Next, the obtained novolac-type phenol resin solution was dissolved in tetrahydrofuran, the solvent for measurement, to prepare a sample for molecular weight distribution measurement. The amount of residual low molecular weight components with a weight-average molecular weight of 800 or less was measured by measuring the molecular weight distribution. The results are shown in Tables 1, 2, and 3.

[0074] (2) Fractionation of Example 2 (2-1) 100 parts by mass of the same novolac-type phenolic resin as in Example 1, and butyl acetate (SP) which is solvent A. A =8.72, D A =0.88, purity 99%) 100 parts by mass and solvent B, which is ethylene glycol (SP B =17.8, D B A resin solution was obtained by dissolving 200 parts by mass of a substance with a purity of 99% (=1.11).

[0075] (2-2) After mixing and stirring the obtained resin solution, it was left to stand for 2 hours at a temperature of 40°C to separate into two phases. In the phase-separated state, the phase containing solvent B became the lower phase. The lower phase was removed by gravity from the bottom of the container, leaving the upper phase in the container. This operation was repeated two more times. In other words, a total of three extraction operations were performed.

[0076] (2-3) A novolac-type phenol resin solution was obtained from the upper phase obtained through the operation in (2-2) above, from which low molecular weight components had been removed. The amount of low molecular weight components with a weight-average molecular weight of 800 or less remaining in the obtained novolac-type phenol resin solution was measured in the same manner as in Example 1. The results are shown in Table 1.

[0077] (3) Fractionation of Example 3 (3-1) 100 parts by mass of the same novolac-type phenolic resin as in Example 1, and butyl acetate (SP) which is solvent A. A =8.72, D A =0.88, purity 99%) 100 parts by mass and solvent B, glycerin (SP B =20.0, D B A resin solution was obtained by dissolving 200 parts by mass of a solution with a purity of 99% and a concentration of 1.26.

[0078] (3-2) After mixing and stirring the obtained resin solution, it was left to stand for 2 hours at a temperature of 40°C to separate into two phases. In the phase-separated state, the phase containing solvent B became the lower phase. The lower phase was removed by gravity from the bottom of the container, leaving the upper phase in the container. This operation was repeated two more times. In other words, a total of three extraction operations were performed.

[0079] (3-3) From the upper phase obtained through the operation in (3-2) above, the amount of low molecular weight components with a weight-average molecular weight of 800 or less remaining in the obtained novolac-type phenol resin solution was measured in the same manner as in (2-3) above. The results are shown in Table 1.

[0080] [Table 1]

[0081] (4) Fraction of Example 4 (4-1) 100 parts by mass of the same novolac-type phenolic resin as in Example 1, and methyl isobutyl ketone (SP) as solvent A. A =8.68, D A =0.80, purity 99%) 100 parts by mass, and ethylene glycol (SP) which is solvent component B1 of solvent B. B1 =17.8, D B1 =1.11, purity 99%) 200 parts by mass and water (SP) which is solvent component B2. B2 =26.7, D B A resin liquid was obtained using 3 parts by mass of (1.00, 99% purity).

[0082] (4-2) After mixing and stirring the obtained resin solution, it was left to stand for 2 hours at a temperature of 40°C to separate into two phases. In the phase-separated state, the phase containing solvent B became the lower phase. The lower phase was removed by gravity from the bottom of the container, leaving the upper phase in the container. This operation was repeated two more times. In other words, a total of three extraction operations were performed. (4-3) From the upper phase obtained through the operation in (4-2) above, the amount of low molecular weight components with a weight-average molecular weight of 800 or less remaining in the obtained novolac-type phenol resin solution was measured in the same manner as in (1-3) above. The results are shown in Table 2.

[0083] (5) Fraction of Example 5 (5-1) The same resin solution as in Example 1 was obtained except that the amount of water, which is solvent component B2, was 10 parts by mass. Similar to (5-2) and (4-2), the extraction procedure was performed a total of three times in which the phase containing solvent B was the lower phase. (5-3) The amount of low molecular weight components with a weight-average molecular weight of 800 or less remaining in the novolac-type phenol resin solution obtained in the same manner as in (4-3) above was measured. The results are shown in Table 2.

[0084] (6) Fractionation of Example 6 (6-1) The same resin solution as in Example 1 was obtained, except that the amount of water, which is solvent component B2, was 20 parts by mass. Similar to (6-2) and (4-2), the extraction operation was performed a total of three times in which the phase containing solvent B was the lower phase. (6-3) The amount of low molecular weight components with a weight-average molecular weight of 800 or less remaining in the novolac-type phenolic resin obtained in the same manner as in (4-3) above was measured. The results are shown in Table 2.

[0085] (7) Fraction of Example 7 (7-1) The same resin solution as in Example 1 was obtained except that the amount of water, which is solvent component B2, was 50 parts by mass. Similar to (7-2) and (4-2), the extraction operation was performed a total of three times in which the phase containing solvent B was the lower phase. (7-3) The amount of low molecular weight components with a weight-average molecular weight of 800 or less remaining in the novolac-type phenolic resin obtained in the same manner as in (4-3) above was measured. The results are shown in Table 2.

[0086] [Table 2]

[0087] (8) Fraction of Example 8 (8-1) 100 parts by mass of a novolac-type phenol resin (phenol compound = cresol, aldehyde component = formaldehyde, catalyst = oxalic acid, F / P ≤ 1) containing 22.1% by mass of a low molecular weight component with a weight-average molecular weight of 800 or less, and 6.5% by mass of a low molecular weight component that is a dimer component, and solvent A, methyl isobutyl ketone (SP A =8.68, D A =0.80, purity 99%) 100 parts by mass and solvent B, which is ethylene glycol (SP B1 =17.8, D B1 A resin solution was obtained by dissolving 100 parts by mass of a substance with a purity of 99% (=1.11).

[0088] (8-2) After mixing and stirring the obtained resin solution, it was left to stand for 2 hours at a temperature of 40°C to separate into two phases. In the phase-separated state, the phase containing solvent B became the lower phase. The lower phase was removed by gravity from the bottom of the container, leaving the upper phase in the container. This operation was repeated two more times. In other words, a total of three extraction operations were performed.

[0089] (8-3) From the upper phase obtained through the operation in (8-2) above, the amount of low molecular weight components with a weight-average molecular weight of 800 or less remaining in the obtained novolac-type phenol resin solution and the amount of dimer components (low molecular weight components) remaining in the obtained novolac-type phenol resin were measured in the same manner as in (1-3) above. The results are shown in Table 3.

[0090] (9) Fractionation of Example 9 (9-1) 100 parts by mass of a novolac-type phenol resin (phenol compound = cresol, aldehyde component = formaldehyde, catalyst = oxalic acid, F / P ≤ 1) containing 22.1% by mass of a low molecular weight component with a weight-average molecular weight of 800 or less, and 4.8% by mass of a low molecular weight component that is a dimer component, and solvent A, methyl isobutyl ketone (SP A =8.68, D A =0.80, purity 99%) 150 parts by mass and solvent B, ethylene glycol (SP B1 =17.8, DB1 A resin solution was obtained by dissolving 200 parts by mass of a substance with a purity of 99% (=1.11).

[0091] In the same manner as in (9-2) and (8-2), an extraction operation was performed a total of three times in which the phase containing solvent B was the lower phase. (9-3) The amount of low molecular weight components with a weight-average molecular weight of 800 or less remaining in the novolac-type phenol resin solution obtained in the same manner as in (8-3) above, and the amount of dimer components (low molecular weight components) remaining in the obtained novolac-type phenol resin solution were measured. The results are shown in Table 3.

[0092] (10) Fraction of Example 10 (10-1) The same resin solution as in Example 8 was obtained except that the amount of ethylene glycol, which is solvent component B, was 300 parts by mass. (10-2) In the same manner as in (8-2) above, an extraction operation was performed a total of three times in which the phase containing solvent B was the lower phase. (10-3) The amount of low molecular weight components with a weight-average molecular weight of 800 or less remaining in the novolac-type phenol resin solution obtained in the same manner as in (8-3) above, and the amount of dimer components (low molecular weight components) remaining in the obtained novolac-type phenol resin solution were measured. The results are shown in Table 3.

[0093] (11) Fractionation of Example 11 (11-1) The same resin solution as in Example 8 was obtained except that the amount of ethylene glycol, which is solvent component B, was 400 parts by mass. (11-2) In the same manner as in (8-2) above, an extraction operation was performed a total of three times in which the phase containing solvent B was the lower phase. (11-3) The amount of low molecular weight components with a weight-average molecular weight of 800 or less remaining in the novolac-type phenol resin solution obtained in the same manner as in (8-3) above, and the amount of dimer components (low molecular weight components) remaining in the obtained novolac-type phenol resin solution were measured. The results are shown in Table 3.

[0094] [Table 3]

[0095] (12) Fraction of Comparative Example 1 (12-1) 100 parts by mass of a novolac-type phenol resin (phenol compound = cresol, aldehyde component = formaldehyde, catalyst = oxalic acid, F / P ≤ 1) containing 22.1% by mass of low molecular weight components with a weight-average molecular weight of 800 or less, and solvent A, methyl isobutyl ketone (SP A =8.68, D A =0.80, purity 99%) 100 parts by mass and solvent B, heptane (SP B =7.43, D B A resin solution was obtained by dissolving 200 parts by mass of a substance with a purity of 99% (0.69%). Furthermore, since the vapor pressure of heptane at 20°C is 4600 Pa, the vapor pressure of heptane at 25°C will be over 1000 Pa.

[0096] (12-2) After mixing and stirring the obtained resin solution, it was left to stand for 2 hours at a temperature of 40°C to separate into two phases. In the phase-separated state, the phase containing solvent A became the lower phase. The upper phase was removed by aspirating from the top of the container, leaving the lower phase in the container. This operation was repeated two more times. In other words, a total of three extraction operations were performed.

[0097] (12-3) A novolac-type phenol resin solution was obtained from the lower phase obtained through the operation in (12-2) above, from which low molecular weight components had been removed. Next, the obtained novolac-type phenol resin solution was dissolved in tetrahydrofuran, the solvent for measurement, to prepare a sample for molecular weight distribution measurement. The amount of residual low molecular weight components with a weight-average molecular weight of 800 or less was measured by measuring the molecular weight distribution. The results are shown in Table 4.

[0098] (13) Fractionation of Comparative Example 2 (13-1) 100 parts by mass of a novolac-type phenol resin (phenol compound = cresol, aldehyde component = formaldehyde, catalyst = oxalic acid, F / P ≤ 1) containing 22.1% by mass of low molecular weight components with a weight-average molecular weight of 800 or less, and solvent A, butyl acetate (SPA =8.72, D A =0.88, purity 99%) 100 parts by mass and solvent B, heptane (SP B =7.43, D B A resin solution was obtained by dissolving 200 parts by mass of a substance with a purity of 99% (0.69%).

[0099] (13-2) After mixing and stirring the obtained resin solution, it was left to stand for 2 hours at a temperature of 40°C to separate into two phases. In the phase-separated state, the phase containing solvent A became the lower phase. The upper phase was removed by aspirating from the top of the container, leaving the lower phase in the container. This operation was repeated two more times. In other words, a total of three extraction operations were performed.

[0100] (13-3) A novolac-type phenol resin solution was obtained from the lower phase obtained through the operation in (13-2) above, from which low molecular weight components had been removed. Next, the obtained novolac-type phenol resin solution was dissolved in tetrahydrofuran, the solvent for measurement, to prepare a sample for molecular weight distribution measurement. The amount of residual low molecular weight components with a weight-average molecular weight of 800 or less was measured by measuring the molecular weight distribution. The results are shown in Table 4.

[0101] (14) Fractionation of Comparative Example 3 (14-1) Of the solvent B, the solvent component B1 is methanol (SP B1 =13.8, D B1 =0.79, purity 99%) is added in an amount of 200 parts by mass, and the solvent component B2 is water (SP B2 =26.7, D B A resin solution identical to that in Example 1 was obtained, except that the amount of a component with a purity of 99% (=1.00) was 100 parts by mass. (14-2) After mixing and stirring the obtained resin solution, it was left to stand for 2 hours at a temperature of 40°C to separate into two phases. In the phase-separated state, the phase containing solvent A became the lower phase. The upper phase was removed by aspirating from the top of the container, leaving the lower phase in the container. This operation was repeated two more times. In other words, a total of three extraction operations were performed. Since the vapor pressure of methanol at 20°C is 13,000 Pa, the vapor pressure of methanol at 25°C exceeds 1,000 Pa.

[0102] (14-3) From the upper phase obtained through the operation of (14-2) above, in the same manner as (12-3) above, the amount of low molecular weight components with a weight average molecular weight of 800 or less remaining in the obtained novolak type phenol resin solution was measured. The results are shown in Table 4.

[0103] (15) Fractionation of Comparative Example 4 (15-1) A resin solution identical to that of Example 1 was obtained, except that the blending amount of methanol (SP B1 = 13.8, D B1 = 0.79, purity 99%), which is solvent component B1 of solvent B, was 300 parts by mass, and the blending amount of water (SP B2 = 26.7, D B = 1.00, purity 99%), which is solvent component B2 of solvent B, was 100 parts by mass. (15-2) After mixing and stirring the obtained resin solution, it was left standing for 2 hours in an environment at a temperature of 40°C and separated into upper and lower two phases. In the phase separation state, the phase containing solvent A became the lower phase. The upper phase was suctioned and taken out from above the container, leaving the lower phase in the container. This operation was repeated 2 more times. That is, a total of 3 extraction operations were performed.

[0104] (15-3) From the upper phase obtained through the operation of (15-2) above, in the same manner as (12-3) above, the amount of low molecular weight components with a weight average molecular weight of 800 or less remaining in the obtained novolak type phenol resin solution was measured. The results are shown in Table 4.

[0105]

Table 4

[0106] (16) Fractionation of Comparative Example 5 (16-1) A novolak-type phenolic resin containing 22.1% by mass of a low molecular weight component with a weight average molecular weight of 800 or less (phenolic compound = cresol, aldehyde component = formaldehyde, catalyst = oxalic acid, F / P ≤ 1), 100 parts by mass, was dissolved in 100 parts by mass of propylene glycol monomethyl ether acetate (SP A = 9.11, D A = 0.89, purity 99%), which is Solvent A, to obtain a resin solution.

[0107] (16-2) To the obtained resin solution, 200 parts by mass of methanol (SP B1 = 13.8, D B1 = 0.79, purity 99%), which is Solvent Component B1, and 100 parts by mass of water (SP B2 = 26.7, D B = 1.00, purity 99%), which is Solvent Component B2, were mixed and stirred. Then, it was allowed to stand for 2 hours in an environment at a temperature of 40°C and separated into two upper and lower phases. In the phase separation state, the phase containing Solvent A became the lower phase. The upper phase was suctioned and removed from the upper part of the container, leaving the lower phase in the container. This operation was repeated 2 more times. That is, a total of 3 extraction operations were performed.

[0108] (16-3) A novolak-type phenolic resin solution from which the low molecular weight component was removed was obtained from the lower phase obtained through the operation in (16-2) above. Next, the obtained novolak-type phenolic resin solution was dissolved in tetrahydrofuran, which is the solvent for measurement, to prepare a sample for measuring the molecular weight distribution, and the residual amount of the low molecular weight component with a weight average molecular weight of 800 or less was measured by measuring the molecular weight distribution. The results are shown in Table 5.

[0109] (17) Fractionation of Comparative Example 6 (17-1) A resin solution the same as that in Example 1 was obtained, except that the blending amount of water (SP B = 26.7, D B = 1.00, purity 99%), which is Solvent Component B, was 200 parts by mass. (17-2) After mixing and stirring the obtained resin solution, it was left to stand for 2 hours at a temperature of 40°C to separate into two phases. In the phase-separated state, the phase containing solvent B became the lower phase. The lower phase was removed by gravity from the bottom of the container, leaving the upper phase in the container. This operation was repeated two more times. In other words, a total of three extraction operations were performed.

[0110] (17-3) A novolac-type phenol resin solution was obtained from the upper phase obtained through the operation in (17-2) above, from which low molecular weight components had been removed. Next, the amount of low molecular weight components with a weight-average molecular weight of 800 or less remaining in the obtained novolac-type phenol resin solution was measured in the same manner as described in (16-3) above. The results are shown in Table 5.

[0111] (18) Fraction of Comparative Example 7 (18-1) Water (SP) is solvent component B. B =26.7, D B The same resin solution as in Example 2 was obtained, except that the amount of a component with a purity of 99% (=1.00) was 200 parts by mass. (18-2) After mixing and stirring the obtained resin solution, it was left to stand for 2 hours at a temperature of 40°C to separate into two phases. In the phase-separated state, the phase containing solvent B became the lower phase. The lower phase was removed by gravity from the bottom of the container, leaving the upper phase in the container. This operation was repeated two more times. In other words, a total of three extraction operations were performed.

[0112] (18-3) A novolac-type phenol resin solution was obtained from the upper phase obtained through the operation in (18-2) above, from which low molecular weight components had been removed. Next, the amount of low molecular weight components with a weight-average molecular weight of 800 or less remaining in the obtained novolac-type phenol resin solution was measured in the same manner as described in (16-3) above. The results are shown in Table 5.

[0113] (19) Fraction of Comparative Example 8 (19-1) Of the solvent B, the solvent component B1 is ethylene glycol (SP B1 =17.8, D B1=1.11, purity 99%) is added in an amount of 200 parts by mass, and the solvent component B2 is water (SP B2 =26.7, D B The same resin solution as in Example 1 was obtained, except that the amount of a compound with a purity of 99% was 100 parts by mass. (19-2) After mixing and stirring the obtained resin solution, it was left to stand for 2 hours at a temperature of 40°C to separate into two phases. In the phase-separated state, the phase containing solvent B became the lower phase. The lower phase was removed by gravity from the bottom of the container, leaving the upper phase in the container. This operation was repeated two more times. In other words, a total of three extraction operations were performed.

[0114] (19-3) From the upper phase obtained through the operation in (19-2) above, the amount of low molecular weight components with a weight-average molecular weight of 800 or less remaining in the obtained novolac-type phenol resin solution was measured in the same manner as in (1-3) above. The results are shown in Table 5.

[0115] [Table 5]

[0116] The molecular weight distribution measurements performed in the above-mentioned examples and comparative examples are as follows. The weight-average molecular weight and molecular weight distribution were determined by GPC measurement. A Tosoh HCL-8220 gel permeation chromatograph was used, TSK-GelG4000HXL and G2000HXL (7.8mmφ × 300mm) GPC columns were used, a 254nm UV detector was used, and tetrahydrofuran was used as the elution solvent. Molecular weight distribution measurements were performed under conditions of a flow rate of 1.0 mm / min. The weight-average molecular weight was calculated on a standard polystyrene basis, and the molecular weight distribution was determined by the area ratio of the target substance peaks. [Industrial applicability]

[0117] The present invention is suitably used in fields such as resin manufacturing and resist manufacturing. Specifically, for example, the present invention is suitably used in phenolic resin manufacturing, epoxy resin manufacturing via phenolic resin, resist manufacturing, and the like. [Explanation of Symbols]

[0118] 10; container, 11; outflow tube, 12; stopcock, 15; suction tube, 21; upper phase, 22; lower phase.

Claims

1. The process includes an extraction step in which a resin solution obtained by dissolving a phenol resin in solvent A is mixed with solvent B, and the low molecular weight components of the phenol resin are extracted into solvent B. Solvent component A that constitutes the solvent A Ｎ The weighted average of SP values ​​using the Fedors method is SP Ａ year, Solvent component B that constitutes the aforementioned solvent B Ｎ The weighted average of SP values ​​using the Fedors method is SP Ｂ In that case, The following conditions (1) and (2) must be met: The aforementioned solvent component B Ｎ A method for fractionating phenolic resin, characterized in that the vapor pressure at 25°C is 1000 Pa or less. (1)SP Ａ ≦9.5 (2)14.0≦SP Ｂ ≦20.5

2. The method for fractionating a phenolic resin according to claim 1, wherein the phase obtained by extracting the low molecular weight component into the solvent B constitutes the lower phase.

3. The solvent component A Ｎ The weighted average of the specific gravity is D Ａ and The aforementioned solvent component B Ｎ D is the weighted average of the specific gravities. Ｂ In this case, the method for fractionating a phenolic resin according to claim 1 or 2, which satisfies the following (3). (3)D Ｂ -D Ａ ≧0.2

4. The total mass of the phenolic resin is M Ｐ Let M be the total mass of solvent A. Ａ In that case, 0.5 ≤ M Ａ / M Ｐ A method for fractionating a phenolic resin according to any one of claims 1 to 3, wherein ≤ 3.

5. The total mass of solvent A is M Ａ Let M be the total mass of solvent B. Ｂ In that case, M Ｂ / M Ａ A method for fractionating a phenolic resin according to any one of claims 1 to 4, wherein the value is 1.

6. The aforementioned solvent component B Ｎ A method for fractionating a phenolic resin according to any one of claims 1 to 5, comprising a polyhydric alcohol.

7. A method for fractionating a phenolic resin according to any one of claims 1 to 6, wherein the water content in the solvent B is 25% by mass or less relative to the total amount of solvent B.

8. The solvent component A Ｎ A method for fractionating a phenolic resin according to any one of claims 1 to 7, comprising one or more selected from ketones, esters, and ethers.

9. A method for fractionating a phenolic resin according to any one of claims 1 to 8, wherein the phenolic resin is of the novolac type.

10. The process includes an extraction step in which a resin solution obtained by dissolving a phenol resin in solvent A is mixed with solvent B, and the low molecular weight components of the phenol resin are extracted into solvent B. Solvent component A that constitutes the solvent A Ｎ The weighted average of SP values ​​using the Fedors method is SP Ａ year, Solvent component B that constitutes the aforementioned solvent B Ｎ The weighted average of SP values ​​using the Fedors method is SP Ｂ In that case, The following conditions (1) and (2) must be met: The aforementioned solvent component B Ｎ A method for fractionating phenolic resins, characterized by containing polyhydric alcohols. (1)SP Ａ ≦9.5 (2)14.0≦SP Ｂ ≦20.5

11. The method for fractionating a phenolic resin according to claim 10, wherein the phase obtained by extracting the low molecular weight component into the solvent B constitutes the lower phase.

12. The solvent component A Ｎ D is the weighted average of the specific gravities. Ａ year, The aforementioned solvent component B Ｎ D is the weighted average of the specific gravities. Ｂ In this case, the method for fractionating a phenolic resin according to claim 10 or 11, which satisfies the following (3). (3)D Ｂ -D Ａ ≧0.2

13. The total mass of the phenolic resin is M Ｐ Let M be the total mass of solvent A. Ａ In that case, 0.5 ≤ M Ａ / M Ｐ A method for fractionating a phenolic resin according to any one of claims 10 to 12, wherein the value is ≤ 3.

14. The total mass of solvent A is M Ａ Let M be the total mass of solvent B. Ｂ In that case, M Ｂ / M Ａ A method for fractionating a phenolic resin according to any one of claims 10 to 13, wherein the value is 1.

15. A method for fractionating a phenolic resin according to any one of claims 10 to 14, wherein the water content in the solvent B is 25% by mass or less relative to the total amount of solvent B.

16. The solvent component A Ｎ A method for fractionating a phenolic resin according to any one of claims 10 to 15, comprising one or more selected from ketones, esters, and ethers.

17. A method for fractionating a phenolic resin according to any one of claims 10 to 16, wherein the phenolic resin is of the novolac type.

18. The process includes an extraction step in which a resin solution obtained by dissolving a phenol resin in solvent A is mixed with solvent B, and the low molecular weight components of the phenol resin are extracted into solvent B. Solvent component A that constitutes the solvent A Ｎ The weighted average of SP values ​​using the Fedors method is SP Ａ year, Solvent component B that constitutes the aforementioned solvent B Ｎ The weighted average of SP values ​​using the Fedors method is SP Ｂ In that case, The following conditions (1) and (2) must be met: A method for fractionating phenolic resin, characterized in that the phase obtained by extracting the low molecular weight component into the solvent B constitutes the lower phase. (1)SP Ａ ≦9.5 (2)14.0≦SP Ｂ ≦20.5

19. The solvent component A Ｎ D is the weighted average of the specific gravities. Ａ year, The aforementioned solvent component B Ｎ D is the weighted average of the specific gravities. Ｂ In this case, the method for fractionating a phenolic resin according to claim 18, which satisfies the following (3). (3)D Ｂ -D Ａ ≧0.2

20. The total mass of the phenolic resin is M Ｐ Let M be the total mass of solvent A. Ａ In that case, 0.5 ≤ M Ａ / M Ｐ A method for fractionating a phenolic resin according to claim 18 or 19, wherein ≤ 3.

21. The total mass of solvent A is M Ａ Let M be the total mass of solvent B. Ｂ In that case, M Ｂ / M Ａ A method for fractionating a phenolic resin according to any one of claims 18 to 20, wherein the value is 1.

22. A method for fractionating a phenolic resin according to any one of claims 18 to 21, wherein the water content in the solvent B is 25% by mass or less relative to the total amount of solvent B.

23. The solvent component A Ｎ A method for fractionating a phenolic resin according to any one of claims 18 to 22, comprising one or more selected from ketones, esters, and ethers.

24. A method for fractionating a phenolic resin according to any one of claims 18 to 23, wherein the phenolic resin is of the novolac type.

25. A method for producing a phenolic resin, characterized by comprising a method for fractionating a phenolic resin according to any one of claims 1 to 24.

26. A solvent for phenol resin fractionation used in the fractionation method according to any one of claims 1 to 24, The solvent A is composed of solvent component A Ｎ Weighted average SP values ​​using the Fedors method Ａ SP Ａ It is a solvent with a pH of ≤9.

5. The solvent B is composed of solvent component B Ｎ Weighted average SP values ​​using the Fedors method Ｂ 14.0 ≤ SP Ｂ A solvent for fractionating phenolic resins, characterized by being a solvent with a solvent content of ≤20.5.

Images