Amin-modified phenolic resin and method for producing the same

Abstract

To provide an amine modified phenolic resin that has excellent solubility in acidic aqueous solution and can provide a cured product having improved flexibility, heat resistance and alkali resistance compared to the conventional amine modified phenolic resins, and a method for producing the same.SOLUTION: The present disclosure provides an amine modified phenolic resin having a structure in which a phenolic resin having a biphenyl structure is reacted with a secondary amine compound and formaldehyde and a method for producing the same. The phenolic resin preferably has a weight average molecular weight (Mw) of 1,000-15,000.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an amine-modified phenol resin, a method for producing the same, and an aqueous phenol resin composition containing the amine-modified phenol resin and an acidic compound.

Background Art

[0002] Phenol resins are widely used as raw materials for paints and adhesives, and as precursors and curing agents for epoxy resins because of their excellent corrosion resistance, adhesion, and heat resistance.

[0003] From the perspective of environmental issues such as recent VOC reduction, the aqueous conversion of paint and adhesive compositions has been actively studied, and the demand for aqueous phenol resins has been increasing. An amine-modified phenol resin obtained by introducing an aminomethyl group into a phenol resin is a water-soluble phenol resin and has excellent corrosion resistance and adhesion. Therefore, its use in metal surface treatment agents (chemical conversion treatment agents), binders for electrodeposition paints, aqueous paint additives, etc. has been proposed (Patent Documents 1 to 4).

[0004] In recent years, a composition comprising an amine-modified phenol resin, phosphoric acid, and a chromium fluoride compound has been used as a chemical conversion treatment agent for metal foils used in laminated bodies for the exterior of secondary batteries such as lithium-ion batteries (Patent Document 5).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

[0006] However, while conventional amine-modified phenolic resins exhibit excellent acid resistance and oil resistance due to the high crosslink density of the phenolic resin, they have the drawback of being weak against alkalis. Furthermore, due to the high crosslink density, the resulting film is hard and brittle, and there is a problem that the flexibility and processability of the treated material are impaired.

[0007] In addition, for metal surface treatment agents for metal foils used in laminated bodies for the exterior of non-aqueous batteries, it is required for safety enhancement that the resulting film has good heat resistance. However, conventional metal surface treatment agents using amine-modified phenolic resins also have the problem that the heat resistance of the resulting film is not sufficient.

[0008] An object of the present invention is to provide an amine-modified phenolic resin that is excellent in solubility in acidic aqueous solutions and gives a cured product having flexibility, heat resistance, and alkali resistance superior to those of conventional amine-modified phenolic resins, and a method for producing the same. [Means for Solving the Problems]

[0009] As a result of intensive studies to solve the above problems, the present inventors have found that by using an amine-modified phenolic resin having a structure in which a phenolic resin having a biphenyl structure is reacted with a secondary amine compound and formaldehyde, a cured product having excellent flexibility, heat resistance, and alkali resistance can be obtained, and thus the present invention has been completed.

[0010] The present invention is an amine-modified phenolic resin having a total of 80 mol% or more of the structures represented by the following general formulas (1-1) and (1-2).

[0011] [Chemical Formula] (In the formula, R 1 and R 2each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a hydroxyalkyl group having 1 to 10 carbon atoms, R 3 and R 4 each independently represents an alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, an allyl group, or a benzyl group, p1 and p2 each independently represent an integer from 1 to 3, q1 and q2 each independently represent an integer from 0 to 3, 1 ≦ p1 + q1 ≦ 3 and 1 ≦ p2 + q2 ≦ 3, m represents a number of 0 or more, and n represents a number of 1 or more, m and n are numbers satisfying m / n = 0 to 20.)

[0012] The present invention also provides a method for producing the amine-modified phenol resin, including reacting a phenol resin having a structure represented by the following general formulas (2-1) and (2-2) with 0.8 to 1.5 moles of amines represented by the following general formula (3) and the same molar amount of formaldehyde as the amines, per 1 mole of a benzene ring having a structure to which a hydroxyl group is bonded and present in the structure of the phenol resin.

[0013] [Chemical formula] (In the formula, R 1 and R 2 each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a hydroxyalkyl group having 1 to 10 carbon atoms, R 3 and R 4 each independently represents an alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, an allyl group, or a benzyl group, p1 and p2 each independently represent an integer from 1 to 3, q1 and q2 each independently represent an integer from 0 to 3, 1 ≦ p1 + q1 ≦ 3 and 1 ≦ p2 + q2 ≦ 3, m represents a number of 0 or more, and n represents a number of 1 or more, m and n are numbers that satisfy m / n = 0 to 20.)

[0014] The present invention also relates to an aqueous phenolic resin composition containing any one of the above amine-modified phenolic resin and an acidic compound composed of an inorganic compound, an organic compound, or both of them.)

Advantages of the Invention

[0015] The amine-modified phenolic resin of the present invention is excellent in solubility in an acidic aqueous solution, and a cured product having flexibility, heat resistance, and alkali resistance superior to those of conventional amine-modified phenolic resins can be obtained. Therefore, the amine-modified phenolic resin of the present invention can be suitably used as a resin component of a metal surface treatment agent.)

Embodiments for Carrying Out the Invention

[0016] The amine-modified phenolic resin of the present invention has a total of 80 mol% or more of the structures represented by the following general formulas (1-1) and (1-2).

[0017]

Chemical Formula

[0018] The structures represented by the general formulas (1-1) and (1-2) are structures in which an aminomethyl group represented by the following general formula (a) is substituted on a benzene ring (hereinafter also referred to as "phenol ring") having a structure in which a hydroxyl group in a phenol resin is bonded. Having 80 mol% or more of these structures means that 80 mol% or more of the phenol rings in the phenol resin are substituted with aminomethyl groups.

[0019] [Chemical formula] (In the formula, R 1 and R 2 are the same as R 1 and R 2 in the general formula (1).)

[0020] R 1 , R 2 , R 3 and R 4 Examples of the alkyl group having 1 to 10 carbon atoms represented by R

[0021] , R 1 , R 2 , R 3 and R 4 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, and the like.

[0022] In the present invention, from the viewpoint of improving the solubility in an acidic aqueous solution, the R 1 and R 2is preferably a hydroxyalkyl group having 1 to 10 carbon atoms, more preferably a hydroxyalkyl group having 1 to 4 carbon atoms, and particularly preferably a 2-hydroxyethyl group. That is, the group represented by the general formula (a) is preferably an [N,N-bis(2-hydroxyethyl)amino]methyl group.

[0023] Said R 3 and R 4 are preferably an alkyl group having 1 to 10 carbon atoms, an allyl group or a benzyl group from the viewpoint of the balance of flexibility, heat resistance and alkali resistance of the resulting cured product, more preferably an alkyl group having 1 to 5 carbon atoms or an allyl group, and particularly preferably a methyl group or an allyl group.

[0024] Said p1 and p2 are preferably 1 or 2, and particularly preferably 1, from the viewpoint of the balance of flexibility, heat resistance and alkali resistance of the resulting cured product.

[0025] Said q1 and q2 are preferably an integer of 0 to 2, more preferably 0 or 1, and particularly preferably 0, from the viewpoint of the balance of flexibility, heat resistance and alkali resistance of the resulting cured product.

[0026] Said m and n indicate the ratio of the structures shown in the general formulas (1-1) and (1-2), and their sum indicates the total number of repeating units. From the viewpoints of solubility in an acidic aqueous solution and the balance of flexibility, heat resistance and alkali resistance of the resulting cured product, it is preferable that m / n = 0 to 10, more preferably m / n = 0 to 1, and particularly preferably m / n = 0, that is, m = 0.

[0027] The amine-modified phenol resin preferably has a total of 80 mol% or more, more preferably 90 mol% or more, and particularly preferably 95 mol% or more of the structures shown in the general formulas (1-1) and (1-2) from the viewpoints of solubility in an acidic aqueous solution and the balance of flexibility, heat resistance and alkali resistance of the resulting cured product.

[0028] From the viewpoints of solubility in an acidic aqueous solution and the balance of flexibility, heat resistance, and alkali resistance of the resulting cured product, it is preferable that the amine-modified phenol resin is one in which a group represented by the general formula (a) is substituted on the phenol ring of a phenol resin having a weight average molecular weight (Mw) of 1,000 to 15,000. The weight average molecular weight of the phenol resin is more preferably 1,000 to 5,000, and particularly preferably 1,000 to 3,000. The weight average molecular weight is a value determined as a polystyrene-equivalent molecular weight by gel permeation chromatography (GPC).

[0029] From the viewpoints of solubility in an acidic aqueous solution and the balance of flexibility, heat resistance, and alkali resistance of the resulting cured product, it is preferable that the amine-modified phenol resin is one in which a group represented by the general formula (a) is substituted on the phenol ring of a phenol resin having a hydroxyl equivalent of 150 to 500.

[0030] The amine-modified phenol resin can be produced by reacting a phenol resin having structures represented by the following general formulas (2-1) and (2-2) with 0.8 to 1.5 moles of amines represented by the following general formula (3) and the same molar amount of formaldehyde as the amines with respect to 1 mole of the phenol ring present in the structure of the phenol resin.

[0031] [Chemical formula] (In the formula, R 1 and R 2 each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a hydroxyalkyl group having 1 to 10 carbon atoms, R 3 and R 4 each independently represent an alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, an allyl group, or a benzyl group, p1 and p2 each independently represent an integer of 1 to 3, q1 and q2 each independently represent an integer from 0 to 3, 1 ≦ p1 + q1 ≦ 3 and 1 ≦ p2 + q2 ≦ 3, m represents a number of 0 or more, and n represents a number of 1 or more, m and n are numbers that satisfy m / n = 0 to 20. )

[0032] In the general formulas (2) and (3), R 1 , R 2 , R 3 and R 4 The groups represented by are the same as the groups represented by R 1 , R 2 , R 3 and R 4 in the general formula (1). Also, the numbers represented by p1 and p2, q1 and q2, and m and n in the general formulas (2) and (3) are the same as the numbers represented by p1 and p2, q1 and q2, and m and n in the general formula (1).

[0033] The reaction may be carried out under conditions where the reaction is completed. For example, the phenolic resin and amines are dissolved in a solvent, and an aqueous formaldehyde solution (formalin) is sequentially added dropwise to the resulting solution over 10 to 120 minutes, and then heated at 50 to 120°C for 1 to 12 hours. Thereby, the phenolic ring can be aminomethylated.

[0034] Examples of the amines include propylamine, isopropylamine, butylamine, monoethanolamine, diethanolamine, N-methylethanolamine, propanolamine, isopropanolamine, diisopropanolamine, and the like.

[0035] The amounts of amines and formaldehyde used in the reaction may be appropriately adjusted so that the amount of phenolic rings to be aminomethylated becomes a desired amount. However, it is preferably 0.8 to 1.5 moles, more preferably 1.0 to 1.5 moles, and particularly preferably 1.1 to 1.3 moles, per 1 mole of phenolic rings present in the structure of the phenolic resin.

[0036] In addition, the usage amounts of the amines and formaldehyde are preferably such that the amount of formaldehyde is 0.8 to 1.2 moles, more preferably 0.9 to 1.1 moles, per 1 mole of the amines. Particularly from the viewpoint of reducing unreacted amines and formaldehyde, it is preferable that the amines and formaldehyde be in equimolar amounts.

[0037] The solvent may be any water-soluble solvent that can dissolve the phenol resin. Preferred examples include glycol ether solvents such as ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), ethylene glycol monobutyl ether (butyl cellosolve), propylene glycol monomethyl ether, and diethylene glycol monobutyl ether.

[0038] The phenol resin used in the production of the amine-modified phenol resin of the present invention can be obtained by a known method. Specifically, in the phenol resin having the structures represented by the general formulas (2-1) and (2-2), the phenol resin in which m = 0, that is, the phenol biphenyl resin having the structure represented by the general formula (2-1), is obtained by condensing or co-condensing at least one phenol selected from phenol compounds such as phenol, cresol, xylenol, resorcinol, catechol, and hydroquinone with a bis(methoxymethyl)biphenyl compound such as 4,4'-bis(methoxymethyl)-1,1'-biphenyl or a bis(halogenomethyl)biphenyl compound such as 4,4'-bis(chloromethyl)-1,1'-biphenyl under an acidic catalyst or without a catalyst.

[0039] In addition, the phenol resin in which m ≠ 0 in the phenol resin having the structures represented by the general formulas (2-1) and (2-2) is obtained by condensing or co-condensing the phenols, the bis(methoxymethyl)biphenyl compound or the bis(halogenomethyl)biphenyl compound, and formaldehyde under an acid catalyst or without a catalyst.

[0040] Furthermore, the phenolic resin having the structures represented by the general formulas (2-1) and (2-2) with m≠0 can also be obtained by melt-mixing or dissolving and mixing in the presence of a solvent, a phenolic biphenyl resin having the structure represented by the general formula (2-1), which is obtained by condensing or co-condensing the phenols with a bis(methoxymethyl)biphenyl compound or a bis(halogenomethyl)biphenyl compound under an acid catalyst or without a catalyst, and a phenolic formaldehyde resin having the structure represented by the general formula (2-2), which is obtained by condensing or co-condensing the phenols with formaldehyde under an acid catalyst or without a catalyst.

[0041] The amine-modified phenolic resin of the present invention is produced by reacting a phenolic biphenyl resin having the structure represented by the general formula (2-1) with 0.8 to 1.5 moles of amines represented by the general formula (3) and the same molar amount of formaldehyde as the amines per 1 mole of the phenolic ring present in the resin structure, and can also be produced by mixing an amine-modified phenolic resin produced by reacting a phenolic formaldehyde resin having the structure represented by the general formula (2-2) with 0.8 to 1.5 moles of amines represented by the general formula (3) and the same molar amount of formaldehyde as the amines per 1 mole of the phenolic ring present in the resin structure.

[0042] The phenolic resin having the structures represented by the general formulas (2-1) and (2-2) used in the production of the amine-modified phenolic resin of the present invention preferably has a weight average molecular weight (Mw) of 1,000 to 15,000 from the viewpoints of solubility in an acidic aqueous solution and the balance between the flexibility and heat resistance of the resulting cured product. The weight average molecular weight of the phenolic biphenyl resin having the structure represented by the general formula (2-1) is preferably 1,000 to 5,000, particularly preferably 1,000 to 3,000. The weight average molecular weight of the phenolic formaldehyde resin having the structure represented by the general formula (2-2) is preferably 1,000 to 15,000.

[0043] From the viewpoints of solubility in an acidic aqueous solution and the balance among flexibility, heat resistance, and alkali resistance of the resulting cured product, the phenolic resin used for producing the amine-modified phenolic resin of the present invention preferably has a hydroxyl equivalent of 150 to 500.

[0044] In the amine-modified phenolic resin of the present invention, one of the preferred embodiments for achieving excellent heat resistance, flexibility, and alkali resistance is an amine-modified phenolic biphenyl resin represented by the following general formula (4).

[0045] [Chemical formula] (In the formula, X 1 each independently represents a hydrogen atom or an aminomethyl group represented by the general formula (a), p1a, p1b, and p1c each independently represent an integer of 1 to 3, q1a, q1c, and q1c each independently represent an integer of 0 to 3, 1 ≤ p1a + q1a ≤ 3, 1 ≤ p1b + q1b ≤ 4, and 1 ≤ p1c + q1c ≤ 4, n1 represents a number of 0 or more and 10 or less.)

[0046] However, in the amine-modified phenolic biphenyl resin represented by the general formula (4), 80 mol% or more of all the substituents X 1 present are aminomethyl groups represented by the general formula (a).

[0047] Here, the group represented by R 3 in the general formula (4) is the same as the group represented by R 3 in the general formula (1-1).

[0048] In the amine-modified phenolic resin of the present invention, from the viewpoint of the balance among heat resistance, flexibility, alkali resistance, and cost, one of the preferred embodiments is an amine-modified phenolic resin comprising an amine-modified phenolic biphenyl resin represented by the general formula (4) and an amine-modified phenolic formaldehyde resin represented by the following general formula (5).

[0049] [Chemical Formula] (In the formula, X 2 each independently represents a hydrogen atom or an aminomethyl group represented by the general formula (a), p2a, p2b, and p2c each independently represent an integer of 1 to 3, q2a, q2c, and q2c each independently represent an integer of 0 to 3, 1 ≤ p2a + q2a ≤ 3, 1 ≤ p2b + q2b ≤ 4, and 1 ≤ p2c + q2c ≤ 4, m1 represents a number of 0 or more and 10 or less.)

[0050] However, in the amine-modified phenolic resin comprising the amine-modified phenolic biphenyl resin represented by the general formula (4) and the amine-modified phenolic formaldehyde resin represented by the general formula (5), among the total of the existing substituents X 1 and the substituent X 2 80 mol% or more is an aminomethyl group represented by the general formula (a).

[0051] Here, the group represented by R 4 in the general formula (5) is the same as the group represented by R 4 in the general formula (1-2).

[0052] The content ratio of the amine-modified phenolic biphenyl resin represented by the general formula (4) and the amine-modified phenol formaldehyde resin represented by the general formula (5) is preferably in the range of [mass of the amine-modified phenol formaldehyde resin represented by the general formula (5)] / [mass of the amine-modified phenolic biphenyl resin represented by the general formula (4)] being 0.05 to 10, more preferably 0.1 to 1, and particularly preferably 0.2 to 0.5 or less.

[0053] In the amine-modified phenolic resin of the present invention, from the viewpoint of the balance among heat resistance, flexibility, alkali resistance, and cost, one of the preferred embodiments is an amine-modified phenolic resin represented by the following general formula (6).

[0054] [Chemical formula] (In the formula, X 3 each independently represents a hydrogen atom or an aminomethyl group represented by the general formula (a), R 3 and R 4 each independently represents an alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, an allyl group, or a benzyl group, p1d and p2d each independently represent an integer of 1 to 3, q1d and q2d each independently represent an integer of 0 to 3, 1 ≤ p1d + q1d ≤ 3 and 1 ≤ p2d + q2d ≤ 3, m2 and n2 are numbers satisfying m2 / n2 = 0.01 to 20.)

[0055] However, in the amine-modified phenolic resin represented by the general formula (6), among all the substituents X 3 present, 80 mol% or more is an aminomethyl group represented by the general formula (a).

[0056] Here, R 3 and R 4The group represented by is the same as the groups represented by R in the general formulas (1-1) and (1-2). 3 and R 4 in the general formulas (1-1) and (1-2).

[0057] By the above reaction, the amine-modified phenol resin of the present invention is usually obtained in a solution state. The obtained amine-modified phenol resin solution can be used as it is as a raw material for a metal surface treatment agent, and can also be used after concentration or dilution as necessary.

[0058] The aqueous phenol resin composition of the present invention contains any one of the above amine-modified phenol resin and an acidic compound composed of an inorganic compound or an organic compound or both of them.

[0059] Examples of the inorganic compound include sulfuric acid, hydrochloric acid, phosphoric acid, hydrofluoric acid, polyphosphoric acid, etc., and examples of the organic compound include formic acid, acetic acid, propionic acid, citric acid, lactic acid, malic acid, fumaric acid, maleic acid, etc.

[0060] The aqueous phenol resin composition can be suitably used as a curing agent or an additive for a metal surface treatment agent, an aqueous paint, and an adhesive. From the viewpoints of corrosion resistance and adhesion when the aqueous phenol resin composition is used as a metal surface treatment agent, it is preferable that the aqueous phenol resin composition contains phosphoric acid as an acidic compound.

Examples

[0061] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[0062] [1] Synthesis and evaluation of amine-modified phenol resin The analysis methods and evaluation methods used in the following synthesis and evaluation of amine-modified phenol resin will be described. Hereinafter, unless otherwise specified, “%” means “mass %”.

[0063] <Analysis Method and Evaluation Method of Phenolic Resin as Base Resin> [Weight-average Molecular Weight (Mw)] Using the following gel permeation chromatograph (GPC) apparatus, the weight-average molecular weight (Mw) of the phenolic resin was determined as the polystyrene-equivalent molecular weight under the following conditions. Equipment used: Waters Alliance 2695 Column: LF-804 (manufactured by SHODEX) Guard column: KF-G (manufactured by SHODEX) Measurement conditions: Column pressure 2.7 MPa Solvent: Tetrahydrofuran (THF) Detector: UV-Visivle Detector 2489 Detection wavelength: 254 nm Flow rate: 1 mL / min. Column oven temperature: 40 °C Injection volume: 100 μL Sample concentration: 0.1 mg / mL

[0064] [Hydroxyl Equivalent] The hydroxyl equivalent was measured in accordance with JIS K0070. Specifically, the phenolic resin was acetylated with excess acetic anhydride, and the hydroxyl equivalent was measured by a back-titration method in which the excess acetic anhydride was neutralized and titrated with an alkali.

[0065] <Analysis Method and Evaluation Method of Amine-modified Phenolic Resin> [Appearance] Observed visually.

[0066] [Viscosity] Measured with an E-type viscometer in accordance with JIS K7117-2:1999.

[0067] [Non-volatile Content] 1.0 g of the amine-modified phenolic resin was weighed into an aluminum cup with a diameter of φ50 mm, and it was determined from the remaining amount after drying in an oven at 180 °C for 1 hour.

[0068] [Acid Solubility and Dissolution Time] Weighed 0.2 g (in terms of solid content) of the amine-modified phenolic resin solution into a 200 mL beaker, added 100 mL of phosphoric acid aqueous solution adjusted to pH 2.0, and then immediately stirred with a magnetic stirrer to observe whether it dissolved and measure the dissolution time. The dissolution time was defined as the time from the start of stirring with the magnetic stirrer until the amine-modified phenolic resin dissolved in the phosphoric acid aqueous solution. When it visually became a transparent and uniform solution, it was judged to be dissolved.

[0069] 〔Example 1〕 Into a reaction apparatus equipped with a stirrer, a condenser and a thermometer, 100 g of a phenolic resin represented by the following general formula (I) (phenol biphenyl resin 1: hydroxyl equivalent 218 g / eq., Mw 1,900), 168 g of butyl cellosolve, and 57.9 g (0.55 mol) of diethanolamine were added and dissolved at 70 °C. Then, 39.3 g (0.55 mol) of 42% formalin was added over 1 hour. After the addition, the temperature was raised to 100 °C and reacted at the same temperature for 6 hours to obtain 358.6 g of a solution containing amine-modified phenolic resin A. The amine-modified phenolic resin A has only the structure shown in the general formula (1-1) (that is, m = 0), p1 is 1, q1 is 0, R 1 and R 2 corresponds to the amine-modified phenolic resin in which is a 2-hydroxyethyl group. The obtained solution containing amine-modified phenolic resin A had a viscosity of 238 mPa·s and a non-volatile content of 39.5%. The evaluation results are shown in Table 1.

[0070]

Chemical formula

[0071] 〔Example 2〕 Into a reactor equipped with a stirrer, a condenser and a thermometer, 100 g of a phenolic resin represented by the general formula (I) (phenol biphenyl resin 2: hydroxyl equivalent 206 g / eq., Mw 1,300), 168 g of butyl cellosolve, and 61.0 g (0.58 mol) of diethanolamine were added and dissolved at 70 °C. Then, 41.5 g (0.58 mol) of 42% formalin was added over 1 hour. After the addition, the temperature was raised to 100 °C and the reaction was carried out at the same temperature for 6 hours to obtain 364.9 g of a solution containing amine-modified phenolic resin B. The amine-modified phenolic resin B has only the structure shown in the general formula (1-1) (that is, m = 0), p1 is 1, q1 is 0, R 1 and R 2 corresponds to the amine-modified phenolic resin in which is a 2-hydroxyethyl group. The obtained solution containing amine-modified phenolic resin B had a viscosity of 191 mPa·s and a non-volatile content of 39.5%. The evaluation results are shown in Table 1.

[0072] [Example 3] Into a reactor equipped with a stirrer, a condenser and a thermometer, 70 g of a phenolic resin represented by the general formula (I) (phenol biphenyl resin 1: hydroxyl equivalent 218 g / eq., Mw 1,900), 30 g of a phenolic resin represented by the following general formula (II) (phenol formaldehyde resin: hydroxyl equivalent 107 g / eq., Mw 1,900), 168 g of butyl cellosolve, and 69.1 g (0.66 mol) of diethanolamine were added and dissolved at 70 °C. Then, 47.0 g (0.66 mol) of 42% formalin was added over 1 hour. After the addition, the temperature was raised to 100 °C and the reaction was carried out at the same temperature for 6 hours to obtain 363.7 g of a solution containing amine-modified phenolic resin C. The obtained solution containing amine-modified phenolic resin C had a viscosity of 360 mPa·s and a non-volatile content of 41.7%. The evaluation results are shown in Table 1.

[0073] [Chemical formula] (In the formula, n represents any number that satisfies the hydroxyl equivalent and Mw.)

[0074] [Example 4] Into a reactor equipped with a stirrer, a condenser and a thermometer, 50 g of the phenolic resin represented by the general formula (I) (phenol biphenyl resin 1: hydroxyl equivalent 218 g / eq., Mw 1,900), 50 g of the phenolic resin represented by the general formula (II) (phenol formaldehyde resin: hydroxyl equivalent 107 g / eq., Mw 1,900), 168 g of butyl cellosolve, and 76.6 g (0.73 mol) of diethanolamine were added and dissolved at 70°C. Subsequently, 52.1 g (0.73 mol) of 42% formalin was added over 1 hour. After the addition, the temperature was raised to 100°C and the reaction was carried out at the same temperature for 6 hours to obtain 387.9 g of a solution containing amine-modified phenolic resin D. The obtained solution containing amine-modified phenolic resin D had a viscosity of 415 mPa·s and a non-volatile content of 41.9%. The evaluation results are shown in Table 1.

[0075] [Comparative Example 1] Into a reactor equipped with a stirrer, a condenser and a thermometer, 100 g of the phenolic resin represented by the general formula (II) (phenol formaldehyde resin: hydroxyl equivalent 107 g / eq., Mw 1,900), 168 g of butyl cellosolve, and 95.3 g (0.91 mol) of diethanolamine were added and dissolved at 70°C. Subsequently, 65.1 g (0.91 mol) of 42% formalin was added over 1 hour. After the addition, the temperature was raised to 100°C and the reaction was carried out at the same temperature for 6 hours to obtain 417.7 g of a solution containing amine-modified phenolic resin C. The obtained solution containing amine-modified phenolic resin C had a viscosity of 1373 mPa·s and a non-volatile content of 48%. The evaluation results are shown in Table 1.

[0076] [Table 1]

[0077] [2] Preparation and evaluation of cured product (coating film) of amine-modified phenolic resin The analysis methods and evaluation methods used in the evaluation of the cured product (coating film) of the following amine-modified phenolic resin will be described.

[0078] [Hue] Observation was carried out visually.

[0079] [Flexibility] Using a conical mandrel tester, the flexibility of the coating film was evaluated by the following method. The amine-modified phenolic resin solution obtained in the examples and comparative examples was applied to a commercially available degreased aluminum plate (JIS A5052, 75 mm × 100 mm) with an applicator (gap: 50 μm), and baked at 210 °C for 10 minutes to prepare a test sample with a coating film formed on the aluminum plate. The test sample was set in a conical mandrel tester, and an arm (movable range 180°) with the pivot center at the end of the conical axis was manually operated. The presence or absence of cracking or peeling of the coating film when the coating plate was wound around a conical mandrel having a diameter in the range of φ: 3.2 mm to 16.2 mm within 15 seconds was observed. The flexibility was evaluated according to the following criteria. 〇: No cracking or peeling ×: Cracking or peeling present

[0080] [20% weight loss temperature] A commercially available degreased aluminum plate (JIS A5052) was punched into a φ4 mm circle, and the amine-modified phenolic resin solution obtained in the examples and comparative examples was dropped thereon, and baked at 210 °C for 10 minutes to prepare a test sample with a coating film formed on the aluminum plate. Using the test sample, TG-DTA measurement was performed under the following conditions, and the 20% weight loss temperature was calculated based on the weight obtained by subtracting the weight of the aluminum plate from the sample weight. Apparatus: TG-DTA apparatus manufactured by Hitachi, model name TG-DTA7200 Temperature rising condition: 10 °C / min Measurement temperature: 25 - 550 °C Sample amount: 10 mg Atmosphere: Under a nitrogen stream of 55 mL / min

[0081] [Alkali resistance] A commercially available degreased aluminum plate (JIS A5052, 75 mm × 100 mm) was coated with the amine-modified phenolic resins obtained in Example 1, Example 4, and Comparative Example 1 using an applicator (gap: 50 μm), and baked at 210°C for 10 minutes to prepare test samples with a coating film having a thickness of about 9 μm formed on the aluminum plate. A 5% aqueous sodium hydroxide solution was placed in a 500 ml beaker, and the test sample was immersed therein at 25°C, and the surface state of the coating film 3 hours after immersion was observed. The alkali resistance was evaluated according to the following criteria. ◎: Only minute bubbles are generated in the coating film. ○: Bubbles are generated in the coating film, but there is no corrosion of the base material. ×: There are cracks or peeling of the coating film and significant corrosion of the base material. These evaluation results are shown in Table 2.

[0082]

Table 2

[0083] As shown in Table 2, the amine-modified phenolic resin of the present invention has high flexibility, high heat resistance, and excellent alkali resistance of the obtained cured product.

Claims

1. An amine-modified phenol resin having a total of 80 mol% or more of the structures represented by the following general formulas (1-1) and (1-2). 【Chemical 1】 (In the formula, R １ and R ２ each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a hydroxyalkyl group having 1 to 10 carbon atoms, R ３ and R ４ each independently represents an alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, an allyl group or a benzyl group, p1 and p2 each independently represent an integer from 1 to 3, q1 and q2 each independently represent an integer from 0 to 3, 1 ≤ p1 + q1 ≤ 3 and 1 ≤ p2 + q2 ≤ 3, m represents a number of 0 or more, and n represents a number of 1 or more, m and n satisfy m / n = 0 to 2.04.)

2. The amine-modified phenol resin according to Claim 1, wherein m = 0.

3. A method for producing an amine-modified phenol resin according to Claim 1 or 2, comprising a step of reacting a phenol resin having the structures represented by the following general formulas (2-1) and (2-2) with 0.8 to 1.5 moles of amines represented by the following general formula (3) and formaldehyde in the same molar amount as the amines with respect to 1 mole of a benzene ring having a structure to which a hydroxyl group is bonded and present in the structure of the phenol resin. 【Chemical Formula 2】 (In the formula, R １ and R ２ each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a hydroxyalkyl group having 1 to 10 carbon atoms, R ３ and R ４ each independently represents an alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, an allyl group or a benzyl group, p1 and p2 each independently represent an integer from 1 to 3, q1 and q2 each independently represent an integer from 0 to 3, 1 ≤ p1 + q1 ≤ 3 and 1 ≤ p2 + q2 ≤ 3, m represents a number of 0 or more, and n represents a number of 1 or more, m and n satisfy m / n = 0 to 2.04.)

4. The method for producing an amine-modified phenol resin according to Claim 3, wherein the weight average molecular weight (Mw) of the phenol resin having the structures represented by the general formulas (2-1) and (2-2) is 1,000 to 15,000.

5. An aqueous phenol resin composition containing the amine-modified phenol resin according to Claim 1 or 2 and any one of acidic compounds composed of an inorganic compound, an organic compound, or both of them.

6. A metal surface treatment agent containing the aqueous phenol resin composition according to Claim 5.

7. An aqueous paint containing the aqueous phenol resin composition according to Claim 5.

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