JP2023167998A - Resol type phenol resin, phenolic resin composition, and method for producing resol type phenol resin - Google Patents

Abstract

To provide a resol type phenol resin that combines higher levels of lightweight characteristics with mechanical strength.SOLUTION: A resol type phenol resin includes a structural unit represented by the formula (1). (In the formula (1), R1 and R2 independently represent hydrogen, a methylol group, or a methylene group serving as a connection point, R3 and R4 independently represent a C4-12 saturated hydrocarbon group, X1 and X2 independently represent an optionally substituted aromatic group, and n and m independently represent an integer of 0-2).SELECTED DRAWING: None

Description

The present invention relates to a resol-type phenolic resin, a phenolic resin composition, and a method for producing a resol-type phenolic resin. More specifically, the present invention relates to a resol type phenolic resin, a phenol resin composition, a molded article comprising a cured product of the phenol resin composition, and a method for producing a resol type phenolic resin.

BACKGROUND ART In recent years, from the viewpoint of energy efficiency, there has been an active effort to reduce the weight of parts of transportation machines and the like by replacing them with metals. Thermosetting resins such as phenolic resins are attracting attention as metal substitute parts because they are lighter than metals and have superior heat resistance.

Resol type phenolic resins, which are widely used as thermosetting resins, are usually obtained by reacting phenols and aldehydes under an alkaline catalyst. Most resol type phenolic resins are handled in solution form, and because they exhibit high adhesion to base materials such as various fibers and fillers, they are widely used as binders for various base materials such as organic fibers, metals, and glass. On the other hand, cured resin products are rigid and brittle, so in applications where bending flexibility, toughness, etc. are required, methods of blending various flexibility-imparting agents or modifying the resin are used.
For example, in Patent Document 1, in order to reduce the molding shrinkage rate during molding and obtain high dimensional stability and high toughness, a specific amount of phenolic resin components consisting of a resol type phenolic resin and a novolak type phenolic resin is used. , for a molding material comprising an essential fiber material with a length of 0.3 mm or more and a specific amount of filler component including an inorganic filler, at least a part of the resol type phenolic resin and the novolac type phenolic resin , is disclosed to be elastomer modified.

JP2017-226807A

However, in the conventional technology as disclosed in Patent Document 1, it was not sufficient to reduce the weight of the resin component itself.
Therefore, the present inventor focused on the development of a new resol-type phenolic resin that is lighter in weight, and conducted intensive studies. As a result, they discovered that by making a resol type phenolic resin with a specific fluorene skeleton, it is possible to reduce the weight while maintaining the mechanical strength such as toughness and bending strength that conventional resol type phenolic resins have. completed.

According to the present invention, the following resol type phenolic resin, phenol resin composition, and method for producing a resol type phenolic resin are provided.

（式（１）中、Ｒ_１、Ｒ_２は各々独立して水素、メチロール基または結合点となるメチレン基を表し、Ｒ_３、Ｒ_４は各々独立して炭素数４～１２の飽和炭化水素基を表す。Ｘ_１、Ｘ_２は各々独立して置換基を有していてもよい芳香族基を表し、ｎ、ｍは各々独立して０～２の整数を表す。）
［２］ ［１］に記載のレゾール型フェノール樹脂であって、
比重が１．００～１．２０である、レゾール型フェノール樹脂。
［３］ ［１］または[２]に記載のレゾール型フェノール樹脂であって、
融点が５０～１００℃である、レゾール型フェノール樹脂。
［４］ ［１］乃至[３]いずれか一つに記載のレゾール型フェノール樹脂であって、
質量平均分子量（Ｍｗ）が１０００～３０００である、レゾール型フェノール樹脂。
［５］ ［１］乃至[４]いずれか一つに記載のレゾール型フェノール樹脂を含むフェノール樹脂組成物。
［６］ ［５］に記載のフェノール樹脂組成物であって、
強化繊維を含む、フェノール樹脂組成物。
［７］ ［６］に記載のフェノール樹脂組成物であって、
前記強化繊維は、金属繊維、炭素繊維、ガラス繊維、セラミック繊維、ポリアミド繊維、アラミド繊維、ポリイミド繊維、ポリビニルアルコール繊維、ポリエステル繊維、アクリル繊維、ポリパラフェニレンベンズオキサゾール繊維、ポリエチレン繊維、ポリプロピレン繊維、ポリアクリロニトリル繊維、およびエチレンビニルアルコール繊維の中から選ばれる１種または２種以上を含む、フェノール樹脂組成物。
［８］ ［５］または[６]に記載のフェノール樹脂組成物であって、
前記強化繊維の含有量が、前記フェノール樹脂組成物全量に対して、１０～７０質量％である、フェノール樹脂組成物。
［９］ ［５］乃至［８］いずれか一つに記載のフェノール樹脂組成物であって、
含浸用途に用いられる、フェノール樹脂組成物。
［１０］ ［５］乃至［８］いずれか一つ記載のフェノール樹脂組成物であって、
構造部材に用いられる、フェノール樹脂組成物。
［１１］ ［５］乃至［１０］いずれか一つに記載のフェノール樹脂組成物の硬化物を備える成形品。
［１２］ フェノール類と、フルオレン類とを、第１塩基性触媒の存在下で反応させ反応生成物を得る工程と、
得られた前記反応生成物と、アルデヒド類とを、第２塩基性触媒の存在下で１２０～１８０℃で反応させる工程と、
を含む、レゾール型フェノール樹脂の製造方法。
［１３］ ［１２］に記載のレゾール型フェノール樹脂の製造方法において、
前記フェノール類および前記フルオレン類（ｆ）は、いずれか一方の芳香環上にボロン酸が結合し、他の一方の芳香環にハロゲンが結合している、レゾール型フェノール樹脂の製造方法。 [1] A resol type phenolic resin comprising a structural unit represented by the following formula (1).

(In formula (1), R ₁ and R ₂ each independently represent hydrogen, a methylol group, or a methylene group serving as a bonding point, and R ₃ and R ₄ each independently represent a saturated hydrocarbon having 4 to 12 carbon atoms. (X ₁ and X ₂ each independently represent an aromatic group that may have a substituent, and n and m each independently represent an integer from 0 to 2.)
[2] The resol type phenolic resin according to [1],
A resol type phenolic resin with a specific gravity of 1.00 to 1.20.
[3] The resol type phenolic resin according to [1] or [2],
A resol type phenolic resin with a melting point of 50 to 100°C.
[4] The resol type phenolic resin according to any one of [1] to [3],
A resol type phenolic resin having a mass average molecular weight (Mw) of 1000 to 3000.
[5] A phenolic resin composition comprising the resol type phenolic resin according to any one of [1] to [4].
[6] The phenolic resin composition according to [5],
A phenolic resin composition containing reinforcing fibers.
[7] The phenolic resin composition according to [6],
The reinforcing fibers include metal fibers, carbon fibers, glass fibers, ceramic fibers, polyamide fibers, aramid fibers, polyimide fibers, polyvinyl alcohol fibers, polyester fibers, acrylic fibers, polyparaphenylenebenzoxazole fibers, polyethylene fibers, polypropylene fibers, and polypropylene fibers. A phenolic resin composition containing one or more selected from acrylonitrile fibers and ethylene vinyl alcohol fibers.
[8] The phenolic resin composition according to [5] or [6],
A phenolic resin composition, wherein the reinforcing fiber content is 10 to 70% by mass based on the total amount of the phenolic resin composition.
[9] The phenolic resin composition according to any one of [5] to [8],
A phenolic resin composition used for impregnation purposes.
[10] The phenolic resin composition according to any one of [5] to [8],
A phenolic resin composition used for structural members.
[11] A molded article comprising a cured product of the phenolic resin composition according to any one of [5] to [10].
[12] A step of reacting phenols and fluorenes in the presence of a first basic catalyst to obtain a reaction product;
a step of reacting the obtained reaction product with an aldehyde at 120 to 180° C. in the presence of a second basic catalyst;
A method for producing a resol type phenolic resin, including:
[13] In the method for producing a resol type phenolic resin according to [12],
A method for producing a resol type phenolic resin, wherein the phenols and the fluorenes (f) have a boronic acid bonded to one of the aromatic rings and a halogen bonded to the other aromatic ring.

According to the present invention, it is possible to realize a resol type phenol resin that can achieve weight reduction while maintaining good mechanical strength, a phenol resin composition containing the same, and a method for molding a resol type phenol resin.

FIG. 2 is a diagram showing the results of ¹ H-NMR measurement of the resol type phenolic resin (A) of Example. It is a figure which shows the GPC chart of the resol type phenol resin (A) of an Example.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In the present specification, the notation "a to b" in the description of numerical ranges represents a range from a to b, unless otherwise specified. For example, "1 to 5% by mass" means "1 to 5% by mass".

<Resol type phenolic resin>
The resol type phenolic resin of this embodiment is a novel resin (hereinafter also referred to as "resol type phenolic resin (A)") having a structural unit represented by the following formula (1). The resol type phenolic resin (A) has a predetermined fluorene skeleton.

（式（１）中、Ｒ_１、Ｒ_２は各々独立して水素、メチロール基または結合点となるメチレン基を表し、Ｒ_３、Ｒ_４は各々独立して炭素数４～１２の飽和炭化水素基を表す。Ｘ_１、Ｘ_２は各々独立して置換基を有していてもよい芳香族基を表し、ｎ、ｍは各々独立して０～２の整数を表す。）

(In formula (1), R ₁ and R ₂ each independently represent hydrogen, a methylol group, or a methylene group serving as a bonding point, and R ₃ and R ₄ each independently represent a saturated hydrocarbon having 4 to 12 carbon atoms. (X ₁ and X ₂ each independently represent an aromatic group that may have a substituent, and n and m each independently represent an integer from 0 to 2.)

By including the structural unit represented by formula (1), the resol type phenolic resin (A) can maintain good strength while realizing weight reduction of the resin. Although the details of this are not clear, the multiple aromatic groups provide rigidity and mechanical strength, while the increased bulk provides low specific gravity, while the saturated hydrocarbon group with a relatively large number of carbon atoms provides toughness. It is speculated that it will be possible to reduce the weight while doing so.

In formula (1), examples of the aromatic group include a phenyl group, a biphenyl group, a naphthyl group, an anthracene group, etc., and among them, a phenyl group and a biphenyl group are preferable. That is, it is preferable that a plurality of phenyl groups are covalently bonded through a single bond.

Furthermore, in formula (1), R ₃ and R ₄ are each independently a saturated hydrocarbon group having 4 to 12 carbon atoms, preferably a saturated hydrocarbon group having 6 to 11 carbon atoms, and more preferably a saturated hydrocarbon group having 6 to 11 carbon atoms. It is a saturated hydrocarbon group of number 8 to 10. Moreover, the saturated hydrocarbon groups of R ₃ and R ₄ are each either linear or branched, and from the viewpoint of facilitating weight reduction, both are preferably linear.

[specific gravity]
The specific gravity of the resol type phenolic resin (A) of this embodiment is preferably 1.00 to 1.20, more preferably 1.00 to 1.10.
By setting the specific gravity of the resol type phenolic resin (A) to be equal to or higher than the above lower limit, good strength can be obtained and heat resistance and dimensional stability can be maintained. On the other hand, weight reduction can be achieved by setting the specific gravity of the resol type phenolic resin (A) to be equal to or less than the above upper limit.

The weight average molecular weight (Mw) of the resol type modified phenolic resin (A) is preferably 1000 to 3000, more preferably 1200 to 1800.

In this embodiment, the values of the mass average molecular weight and number average molecular weight can be determined by gel permeation chromatography (GPC) measurement using polystyrene as a standard substance.

The melting point of the resol type modified phenolic resin (A) of this embodiment is preferably 50 to 100°C, more preferably 70 to 90°C. Most conventional resol type phenolic resins are liquid at room temperature (20°C), but resol type phenolic resin (A) can be solid at room temperature (20°C).

<Production method of resol type phenol>
Next, a method for producing resol type phenol (A) will be explained.
The method for producing resol type phenol (A) includes the following steps.
[Step 1] A step of reacting phenols (p) and fluorenes (f) in the presence of a first basic catalyst to obtain a reaction product.
[Step 2] A step of reacting the obtained reaction product with the aldehyde (d) at 120 to 180° C. in the presence of a second basic catalyst.
Each step will be explained in detail below.

[Step 1]
First, phenols (p) and fluorenes (f) are reacted in the presence of a first basic catalyst to obtain a reaction product. At this time, in the phenols (p) and the fluorenes (f), a boronic acid is bonded to one of the aromatic rings, and a halogen is bonded to the other aromatic ring.

Phenols (p) include phenol; cresols such as o-cresol, m-cresol, and p-cresol; ethylphenols such as o-ethylphenol, m-ethylphenol, and p-ethylphenol; isopropylphenol, butylphenol; , p-tert-butylphenol and other butylphenols; p-tert-amylphenol, p-octylphenol, p-nonylphenol, p-cumylphenol and other alkylphenols; fluorophenol, chlorophenol, bromophenol, iodophenol and other halogens substituted monohydric phenols such as p-phenylphenol, aminophenol, nitrophenol, dinitrophenol, and trinitrophenol; monohydric phenols such as 1-naphthol and 2-naphthol; and resorcinol, alkylresorcinol, Examples include polyhydric phenols such as pyrogallol, catechol, alkylcatechol, hydroquinone, alkylhydroquinone, phloroglucin, bisphenol A, bisphenol F, bisphenol S, and dihydroxynaphthalene, among which boronic acid is bonded on the aromatic ring, Alternatively, one in which a halogen is bonded to an aromatic ring is used. Furthermore, the phenols (p) can be used alone or in combination of two or more.

More specifically, those having structures shown in the following formulas (a-1) to (a-3) can be mentioned.

Examples of the fluorenes (f) include alkyl-substituted fluorenes having 4 to 12 carbon atoms. For example, 9,9-dibutylfluorene, 9,9-dipentylfluorene, 9,9-hexylfluorene, 9,9-diheptylfluorene, 9,9-dioctylfluorene, 9,9-dinonylfluorene, 9,9- Examples include didecylfluorene, 9,9-diundecylfluorene, 9,9-didodecylfluorene, and derivatives thereof, among which boronic acid is bonded to the aromatic ring, or halogen is bonded to the aromatic ring. is used.

Furthermore, specific examples of fluorenes (f) having a halogen bonded to them include those represented by the following formula (2).

（式（２）中、Ｒ_５、Ｒ_６は各々独立して炭素数４～１２の飽和炭化水素基を表す。Ｙ_１、Ｙ_２は各々独立して臭素、ヨウ素、塩素、またはフッ素のいずれかのハロゲン原子を示す。）

(In formula (2), R ₅ and R ₆ each independently represent a saturated hydrocarbon group having 4 to 12 carbon atoms. Y ₁ and Y ₂ each independently represent bromine, iodine, chlorine, or fluorine. )

Examples of the first basic catalyst include hydroxides of alkali metals or alkaline earth metals such as sodium hydroxide, potassium hydroxide, and calcium hydroxide; carbonates such as sodium carbonate, calcium carbonate, and potassium carbonate; lime, etc. Sulfites such as sodium sulfite; phosphates such as sodium phosphate; amines such as ammonia, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, hexamethylenetetramine, and pyridine.

Moreover, a palladium catalyst is used as a catalyst for advancing the coupling reaction. Examples of the palladium catalyst include tetrakis(triphenylphosphine)palladium (Pd(PPh ₃ ) ₄ ), palladium on carbon, and the like.
Further, when a mixed solvent of water and an organic solvent is used, a phase transfer catalyst may be used for the purpose of promoting the reaction between two phases. Examples of the phase transfer catalyst include tetrabutylammonium chloride and tetrabutylammonium bromide.

In step 1, water is generally used as the reaction solvent for the synthesis of the resol type phenolic resin (A), but an organic solvent may also be used.
Examples of the organic solvent include alcohols, ethers, ketones, aromatics, dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF).
Specific examples of alcohols include methanol, ethanol, propyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, glycerin, and the like. Specific examples of ethers include cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, and 4-methyltetrahydropyran. Specific examples of ketones include acetone, methyl ethyl ketone, and the like. Specific examples of aromatics include toluene, xylene, and the like.
These may be used alone or in combination of two or more. Among these, mixed solvents of water, alcohols, and ethers are preferred.

In step 1, phenols (p) and fluorenes (f) are preferably used in a molar ratio (p/f) of 1.5 to 3. Further, the first basic catalyst (b) and the phenol (p) are preferably prepared so that the molar ratio (b/p) is 1.5 to 3. Phenols (reaction products) having a fluorene skeleton are obtained by reacting phenols (p) and fluorenes (f) at 80 to 110°C for 12 to 36 hours.
Moreover, it is preferable that Step 1 is performed under an inert gas atmosphere.

[Step 2]
Next, the obtained reaction product and aldehyde (d) are reacted at 120 to 180°C in the presence of a second basic catalyst to obtain a resol type phenolic resin (A) having a fluorene skeleton. . That is, phenols (reaction products) having a fluorene skeleton are converted into resols.

Examples of aldehydes (d) include formaldehyde, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, polyoxymethylene, chloral, hexamethylenetetramine, furfural, glyoxal, n-butyraldehyde, caproaldehyde, allylaldehyde, benzaldehyde, and crotonaldehyde. , acrolein, tetraoxymethylene, phenylacetaldehyde, o-tolualdehyde, salicylaldehyde and the like. These may be used alone or in combination of two or more. Further, precursors of these aldehydes or solutions of these aldehydes can also be used. Among these, from the viewpoint of production cost, it is preferable to use a formaldehyde aqueous solution.

The second basic catalyst can be the same as those listed for the first basic catalyst in Step 1, and the second basic catalyst may be the same as the first basic catalyst or a different one. It may be. From the viewpoint of effectively performing resolization, the second basic catalyst is preferably an alkali or alkaline earth metal hydroxide.

In addition, the reaction solvent in step 2 can be the same as the reaction solvent in step 1, and the reaction solvent in step 2 may be the same as the reaction solvent in step 1, or it can be different. It may be. The reaction solvent in step 2 is preferably a mixed solvent of water, alcohol, and dimethyl sulfoxide (DMSO) from the viewpoint of obtaining good solubility.

In Step 2, the aldehyde (d) is preferably used in a molar ratio of 10 to 50 with respect to the reaction product obtained in Step 1. Thereby, the remaining amounts of unreacted phenols and unreacted aldehydes can be reduced.
Further, the second basic catalyst is preferably used in a molar ratio of 10 to 30 with respect to the reaction product obtained in step 1. By reacting the reaction product and the aldehyde (d) at 120 to 180°C for 0.5 to 3 hours, methylol is produced in the phenol, and the resolization reaction can proceed. Thereby, resol type phenol resin (A) is obtained. The reaction temperature is preferably 130 to 160°C.

By adjusting the reaction conditions, the number of methylols can be adjusted. The methylol group in the resol type phenolic resin (A) can be determined by ¹ H-NMR measurement.

<Phenol resin composition>
The phenolic resin composition of this embodiment (hereinafter also simply referred to as "resin composition") contains the above-mentioned resol type phenolic resin (A). The phenol resin composition of this embodiment can achieve both weight reduction and mechanical strength due to the rigid structure of the resol type phenol resin (A).

Hereinafter, details of each component contained in the resin composition of this embodiment will be explained.

[Reinforced fiber]
The resin composition of this embodiment may also contain reinforcing fibers. In this embodiment, reinforcing fibers are used to increase mechanical strength and heat resistance.
Examples of reinforcing fibers include metal fibers, carbon fibers, glass fibers, ceramic fibers, polyamide fibers, aramid fibers, polyimide fibers, polyvinyl alcohol fibers, polyester fibers, acrylic fibers, polyparaphenylenebenzoxazole fibers, polyethylene fibers, and polypropylene fibers. , polyacrylonitrile fiber, and ethylene vinyl alcohol fiber. Among these, carbon fibers and glass fibers are preferred because they are effective in improving the strength of molded products.
Furthermore, the reinforcing fibers may be surface-treated.

Further, the content of the reinforcing fibers is adjusted appropriately depending on the use, but for example, the content of the reinforcing fibers is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and still more preferably 30% by mass, based on the total amount of the resin composition. ~65% by mass. By setting the reinforcing fiber content to the above lower limit or more, mechanical strength and heat resistance can be improved. On the other hand, by setting the content of reinforcing fibers to the above upper limit or less, weight reduction can be achieved and moldability can be maintained favorably.

[Curing aid]
The resin composition of this embodiment may also contain a curing aid.
Examples of the curing aid include curing aids known in the field of resin compositions. Examples include alkaline earth metal oxides or hydroxides such as magnesium oxide, calcium hydroxide, and barium hydroxide; and aromatic carboxylic acids such as salicylic acid and benzoic acid.

[Inorganic filler]
The resin composition of this embodiment can use an inorganic filler. The inorganic filler can impart mechanical properties, dimensional stability, etc. to the resin composition.
The inorganic filler is not particularly limited, but one or more types selected from clay, calcium carbonate, talc, aluminum hydroxide, etc. can be used. Among them, it is more preferable to use clay in consideration of the performance required of the resin composition (mechanical properties, electrical properties, flame retardance, dimensional stability, water resistance, etc.).
Note that some inorganic fillers such as aluminum hydroxide also have an effect as a flame retardant aid.

The content of the above-mentioned inorganic filler is appropriately adjusted depending on the application, but for example, it is preferably 1 to 10% by mass, more preferably 2 to 5% by mass based on the entire resin composition. . By setting the content of the inorganic filler to the above-mentioned lower limit or more, good mechanical properties and heat resistance can be maintained, and by setting the content of the inorganic filler to the above-mentioned upper limit or less, the processability of the resin composition can be improved.

[Elastomer]
For the resin composition of this embodiment, an elastomer can be used. Elastomers can maintain dimensional stability and increase the toughness of molded products.
Examples of the elastomer include acrylonitrile butadiene rubber, isoprene, styrene butadiene rubber, and ethylene propylene rubber. Among these, acrylonitrilyl butadiene rubber is preferred.
The content of the above-mentioned elastomer is appropriately adjusted depending on the application, but for example, it is preferably 1 to 10% by mass, more preferably 2 to 5% by mass, based on the entire resin composition. By setting the content of the elastomer to the above-mentioned lower limit or more, good mechanical properties can be maintained, and by setting the content of the elastomer to below the above-mentioned upper limit, the processability of the resin composition can be improved.

[Other ingredients]
The resin composition of the present embodiment may contain other components other than those described above, as long as the effects of the invention are not impaired. Examples of other components include additives such as thermosetting resins and thermoplastic resins other than those mentioned above, curing agents, mold release agents, pigments, flame retardants, adhesion improvers, and coupling agents.
When the resin composition of this embodiment contains these other components, it may contain only one type, or may contain two or more types.

Examples of the thermoplastic resin include resins having a triazine ring such as urea resin and melamine resin, bismaleimide resins, silicone resins, and resins having a benzoxazine ring.

Examples of the above mold release agent include fatty acids such as stearic acid, fatty acid salts such as calcium stearate and zinc stearate, fatty acid amides, and polyethylene.
When a mold release agent is used, its content is, for example, 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the resol type phenolic resin (A).

Examples of the above pigments include carbon black. In addition, various coloring pigments can also be used to obtain molded products of desired colors.
When a pigment is used, its content is, for example, 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the resol type phenolic resin (A).

Examples of the above-mentioned coupling agents include epoxy silane coupling agents, cationic silane coupling agents, silane coupling agents such as aminosilane coupling agents, titanate coupling agents, and silicone oil type coupling agents. . One type of coupling agent may be used alone, or two or more types may be used in combination. In this embodiment, a silane coupling agent is preferably used. It is believed that the use of a coupling agent improves the compatibility between the inorganic filler and other components, and improves the mechanical properties and heat resistance of the resin composition.

The resin composition of this embodiment may contain a solvent (organic solvent, etc.). However, from the viewpoint of ease of distribution and handling as a resin composition, suppression of VOC generation in the working environment, etc., it is preferable that the resin composition of the present embodiment does not substantially contain a solvent (organic solvent, etc.).

<Method for manufacturing resin composition>
The method for producing the resin composition of the present embodiment is obtained by mixing the above-mentioned components by a known method. For example, after blending the above components and mixing them uniformly, they are heated, melted and kneaded using a kneading device such as a roll, a co-kneader, or a twin-screw extruder, or a combination of a roll and other mixing device, and then granulated or pulverized. used.

<Molded product/molded product manufacturing method>
The molded article of this embodiment can be obtained by a known method, but for example, the resin composition of this embodiment is melted or dissolved in a solvent such as ethanol to form a liquid, and reinforcing fibers are immersed therein. The resin composition of the embodiment is impregnated into reinforcing fibers. Thereafter, the resin is dried and heated and pressed into a desired shape, thereby curing the resin and producing a molded product. Although the molding conditions depend on the thickness of the molded article, for example, molding can be carried out at a mold temperature of 170 to 190° C., a molding pressure of 0.01 to 1 MPa, and a curing time of 2 to 10 minutes. Thereafter, additional curing may be performed by further heating.

[Application]
The use of the molded product is not particularly limited. Examples of applications include various structural members such as automobiles, aircraft, railway vehicles, ships, office equipment, general-purpose machines, household appliances, and electrical equipment. It can also be applied to impregnation applications and binder applications in which various base materials such as organic fibers, metals, and glass are impregnated. Of course, uses other than these are not excluded.

Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and the present invention includes modifications, improvements, etc. within a range that can achieve the purpose of the present invention.

Embodiments of the present invention will be described in detail based on Examples and Comparative Examples. Note that the present invention is not limited to the examples.

(1) Synthesis of resol type phenolic resin (A) [Step 1]
19.0 g of 4-hydroxyphenylboronic acid (manufactured by Tokyo Kasei Kogyo Co., Ltd.), 25.3 g of 2,7-dibromo-9,9-di-n-octylfluorene (manufactured by Tokyo Kasei Kogyo Co., Ltd.), potassium carbonate (manufactured by Tokyo Kasei Kogyo Co., Ltd.) 83.8 g of water, 155.0 g of tetrahydrofuran, and 31.0 g of ethanol were added to and dissolved in 25.4 g of tetrabutylammonium chloride (manufactured by Tokyo Kasei Kogyo Co., Ltd.). To this solution, 2.1 g of tetrakis(triphenylphosphine)palladium (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added under a nitrogen atmosphere, heated to 90° C. in an oil bath, and reacted for 24 hours. Thereafter, the organic layer was taken out, the organic solvent was removed, and the resulting solid was purified with a silica gel column (solvent: dichloromethane) to obtain 16.8 g of a reaction product.
[Step 2]
To 12.0 g of the reaction product obtained in the above step 1, 50.8 g of a 37% formaldehyde aqueous solution (manufactured by Tokyo Chemical Industry Co., Ltd.), 70 g of dimethyl sulfoxide, and 33 g of ethanol were added and dissolved. To this solution, 12 g of 50% aqueous sodium hydroxide solution was added, heated to 150° C. in an oil bath, and reacted for 1 hour. Thereafter, 150 g of water was added and the precipitated solid was collected by filtration to obtain 11.8 g of a reaction product, resol type phenol resin (A).

(2) Analysis/Measurement The obtained resol type phenolic resin (A) was subjected to ¹ H-NMR and GPC measurements under the following conditions. The results are shown in Figures 1 and 2, respectively.
< ^1H -NMR measurement conditions>
Equipment: JNM-ECA400 manufactured by JEOL Ltd.
Solvent: DMSO (dimethyl sulfoxide)-d6
Pulse angle: 45°
Sample concentration: 3wt%
Accumulated number of times: 16 times

<GPC measurement>
・Gel permeation chromatography device “HLC-8320GPC” manufactured by Tosoh Corporation
・Column: “TSKgel GMH G2000H SuperHM-M” manufactured by Tosoh Corporation
・Detector: UV detector for liquid chromatogram ・Measurement temperature: 40℃
・Solvent: THF (tetrahydrofuran)
・Sample concentration: 2.0mg/ml

FIG. 1 is a diagram showing the results of ¹ H-NMR measurement. ¹ H-NMR measurement confirmed that the resol type phenolic resin (A) had 1.5 methylol groups bonded to each fluorene structure. Note that a to f in FIG. 1 correspond to the structure expressed by the following formula.

FIG. 2 is a diagram showing a GPC chart. The mass average molecular weight (Mw) of the resol type phenolic resin (A) was found to be 1481 by GPC measurement.

Moreover, the melting point of the resol type phenolic resin (A) was 80° C., and the specific gravity after curing was 1.09.

(3) Examples and comparative examples <Example 1>
The obtained resol-type modified phenol resin (A) was dissolved in an ethanol solvent so that the solid content concentration was 67%. Carbon fibers ("CO6343" manufactured by Toray Industries, Inc.) were immersed therein for 1 minute so that the proportions (mass %) shown in Table 1 were obtained, thereby impregnating the resol type modified phenolic resin (A) into the carbon fibers. Thereafter, the carbon fiber impregnated with the resol-type modified phenolic resin (A) was taken out, dried at 120°C for 5 minutes, and press hardened using a hydraulic press machine at 0.1 MPa and 180°C for 5 minutes to obtain a molded product. Ta.

<Comparative example 1>
Instead of the resol type modified phenolic resin (A), a conventional resol type phenol resin (PR-50404, manufactured by Sumitomo Bakelite Co., Ltd., specific gravity 1.27 after curing, liquid at room temperature) was used, and the carbon fibers were immersed therein. A molded article was obtained in the same manner as in Example 1 except for the above.

The following evaluations and measurements were performed on the obtained molded product. The results are shown in Table 1.
- Specific gravity: The specific gravity of each molding material was determined by the underwater displacement method.

- Bending strength: A molded product with a width of 10 mm, a thickness of 1 mm, and a length of 100 mm was obtained. Next, the obtained molded article was post-cured at 180° C. for 2 hours. In this way, a test piece for mechanical strength evaluation was prepared. Then, the bending strength (MPa) of the test piece at 25°C was measured.

- Breaking energy: A curve (stress-strain curve) was created that graphed the relationship between stress and strain during the bending test. Next, using strain as a variable, the integral value of stress from the starting point of the bending test to the breaking point was calculated.

Claims (13)

A resol type phenolic resin comprising a structural unit represented by the following formula (1).

(In formula (1), R ₁ and R ₂ each independently represent hydrogen, a methylol group, or a methylene group serving as a bonding point, and R ₃ and R ₄ each independently represent a saturated hydrocarbon having 4 to 12 carbon atoms. (X ₁ and X ₂ each independently represent an aromatic group that may have a substituent, and n and m each independently represent an integer from 0 to 2.) The resol type phenolic resin according to claim 1,
A resol type phenolic resin with a specific gravity of 1.00 to 1.20. The resol type phenolic resin according to claim 1 or 2,
A resol type phenolic resin with a melting point of 50 to 100°C. The resol type phenolic resin according to claim 1 or 2,
A resol type phenolic resin having a mass average molecular weight (Mw) of 1000 to 3000. A phenolic resin composition comprising the resol type phenolic resin according to claim 1 or 2. The phenolic resin composition according to claim 5,
A phenolic resin composition containing reinforcing fibers. The phenolic resin composition according to claim 6,
The reinforcing fibers include metal fibers, carbon fibers, glass fibers, ceramic fibers, polyamide fibers, aramid fibers, polyimide fibers, polyvinyl alcohol fibers, polyester fibers, acrylic fibers, polyparaphenylenebenzoxazole fibers, polyethylene fibers, polypropylene fibers, and polypropylene fibers. A phenolic resin composition containing one or more selected from acrylonitrile fibers and ethylene vinyl alcohol fibers. The phenolic resin composition according to claim 6,
A phenolic resin composition, wherein the reinforcing fiber content is 10 to 70% by mass based on the total amount of the phenolic resin composition. The phenolic resin composition according to claim 5,
A phenolic resin composition used for impregnation purposes. The phenolic resin composition according to claim 5,
A phenolic resin composition used for structural members. A molded article comprising a cured product of the phenolic resin composition according to claim 5. Reacting phenols and fluorenes in the presence of a first basic catalyst to obtain a reaction product;
a step of reacting the obtained reaction product with aldehydes at 120 to 180° C. in the presence of a second basic catalyst;
A method for producing a resol type phenolic resin, including: In the method for producing a resol type phenolic resin according to claim 12,
The method for producing a resol type phenolic resin, wherein the phenols and the fluorenes have a boronic acid bonded to one aromatic ring and a halogen bonded to the other aromatic ring.

Images