JP2020083937A - Method for producing phenolic resin composition - Google Patents

Abstract

To provide a phenolic resin which can give a cured product sufficiently suppressing generation of cracks even when receiving a thermal shock and has sufficiently high fluidity, by an industrially simple method.SOLUTION: A method for producing a phenolic resin composition containing a phenolic resin modified with a (meth)acrylic rubber having a glycidyl group includes a step of modifying the phenolic resin with the (meth)acrylic rubber having a glycidyl group in the presence of 0.1-2.0 mass% of water based on the phenolic resin.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a phenol resin composition.

Phenolic resins are widely used as binders for automobile brake pads, binders for molding materials (compounds), heat-resistant adhesives, and binders for heat-resistant powder coatings. When a phenol resin is used as a binder, it is often mixed with various substances, molded and used.

For example, in Patent Document 1, 100 parts by weight of a polymer substance having a phenolic hydroxyl group and glycidyl are used as a material in which physical properties are not deteriorated even at −30° C. or lower and cracks are not easily generated even when subjected to thermal shock due to repeated cold heat. A phenolic resin composition comprising 1 part by weight to 100 parts by weight of a rubber containing a group and having an epoxy equivalent of 500 to 30,000 is disclosed.

JP-A-56-122867

However, the phenolic resin composition described in Patent Document 1 may have poor fluidity, and for example, when mixed with various substances and molded, the occurrence of cracks may not be sufficiently suppressed.
An object of the present invention is to provide a phenol resin having a sufficiently high fluidity, which can obtain a cured product with sufficient suppression of crack generation even when it is subjected to thermal shock, by an industrially simple method.

The method for producing a phenol resin composition of the present invention is a method for producing a phenol resin composition containing a phenol resin modified with a (meth)acrylic rubber having a glycidyl group, wherein the (meth)acrylic rubber having a glycidyl group is phenol. It is characterized in that the step of modifying the resin is carried out in the presence of 0.1% by mass to 2.0% by mass of water with respect to the phenol resin.

The (meth)acrylic rubber having a glycidyl group is a monomer mixture in which the content of the glycidyl group-containing monomer is 0.5% by mass to 20% by mass based on all the monomers in the monomer mixture. It is preferably a polymer.
The manufacturing method may include a step of pulverizing the phenol resin composition.
The phenol resin is preferably a phenol novolac resin.
In the above-mentioned production method, it is preferable that 100 parts by mass of the phenol resin is modified in an amount of 1 part by mass to 50 parts by mass of the (meth)acrylic rubber having a glycidyl group.
The (meth)acrylic rubber having a glycidyl group is a monomer mixture in which the content of n-butyl (meth)acrylate is 80% by mass to 99.5% by mass based on all the monomers in the monomer mixture. It is preferably a polymer.
The monomer having a glycidyl group is preferably glycidyl methacrylate.
The weight average molecular weight of the (meth)acrylic rubber having a glycidyl group is preferably 10,000 to 15,000.
The manufacturing method may further include a step of adding a curing agent.

ADVANTAGE OF THE INVENTION According to this invention, the phenol resin composition with sufficient fluidity which can obtain the hardened|cured material with sufficient suppression of crack generation even when it receives a thermal shock can be obtained with an industrially simple method.

The phenol resin used in the present invention is a polymer obtained by reacting a phenolic compound with an aldehyde.
Examples of the phenolic compound include alkylphenols having an alkyl group having 1 to 20 carbon atoms such as phenol, cresols, xylenols, ethylphenol, propylphenol, butylphenol, amylphenol, octylphenol, nonylphenol and dodecylphenol; bisphenol A. , Phenylphenol, cumylphenol, styrenated phenol, and other phenols having an alkylphenol-like structure; alkenylphenols such as p-vinylphenol, o-isopropenylphenol, m-isopropenylphenol, and p-isopropenylphenol. Can be mentioned.
Examples of aldehydes include aliphatic aldehydes such as formaldehyde (formaldehyde aqueous solution), paraformaldehyde, trioxymethylene, and hexamethylenetetramine; substituted and unsubstituted aromatic aldehydes and the like.

As the phenol resin, for example, the molar ratio of the aldehyde to the phenolic compound is 0.60 to 0.95 in the presence of an acidic catalyst (eg, hydrochloric acid, sulfuric acid, oxalic acid, p-toluenesulfonic acid, phosphoric acid). In the presence of a phenol novolac resin, a basic catalyst (for example, ammonia, amine), etc., in which the molar ratio of the aldehyde to the phenolic compound is 0.70 to 1.4. Examples thereof include resol resins.
The phenol novolac resin includes divalent metal halides, divalent metal hydroxides (eg magnesium hydroxide, calcium hydroxide, etc.), divalent metal oxides (eg magnesium oxide, cadmium oxide, etc.), Alternatively, a divalent metal organic acid salt (eg, magnesium acetate, zinc acetate, etc.) is used as a catalyst, the pH is adjusted to 2 to 4 with oxalic acid, etc., and the molar ratio of the aldehyde to the phenolic compound is 0.60 to 0.95. The high orthophenol novolac resin obtained by reacting in the range of 1) is also included.

Among these phenolic resins, the phenol novolac resin is preferable from the viewpoint of miscibility with an auxiliary component (for example, filler) used together with the phenolic resin.

The (meth)acrylic rubber having a glycidyl group used in the present invention includes a structural unit derived from a monomer having a glycidyl group, and is derived from a monomer having a (meth)acryloyl group. The elastic body has a structural unit content of 50% by mass or more, preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 99.9% by mass or more. In addition, (meth)acrylic rubber means the generic name of acrylic rubber and methacrylic rubber, and (meth)acryloyl group means the generic name of acryloyl group and methacryloyl group, respectively.

Examples of the monomer having a (meth)acryloyl group that constitutes the (meth)acrylic rubber include acrylic acid esters such as methyl acrylate, ethyl acrylate, and n-butyl acrylate; (methyl methacrylate, methacrylic acid Examples thereof include methacrylic acid esters such as ethyl acid and methacrylic acid n-butyl.
As these (meth)acryloyl group-containing monomers, n-butyl acrylate and n-butyl methacrylate are preferable. Note that acrylate and methacrylate may be collectively referred to as (meth)acrylate.

When the (meth)acrylic rubber contains a constitutional unit derived from n-butyl(meth)acrylate, cracks are generated when the cured product obtained from the phenol resin composition of the present invention is subjected to thermal shock. From the viewpoint of further suppressing the above, the content of n-butyl (meth)acrylate with respect to all the monomers of the monomer mixture is preferably 80% by mass to 99.5% by mass, more preferably 80% by mass to 95% by mass. It is preferably a polymer of a monomer mixture which is mass %.

The (meth)acrylic rubber contains a constitutional unit derived from a monomer having a glycidyl group. By containing the constitutional unit derived from the monomer having a glycidyl group, it becomes possible to react appropriately with the phenol resin.
From the viewpoint that it becomes possible to react appropriately with the phenol resin and the resulting fluidity of the phenol resin composition is excellent, the above-mentioned (meth)acrylic rubber is a glycidyl compound based on all the monomers in the monomer mixture. The content of the monomer having a group is preferably 0.5% by mass to 20% by mass, more preferably 0.5% by mass to 10% by mass, which is a polymer of a monomer mixture.

Examples of the glycidyl group-containing monomer include glycidyl acrylate, glycidyl methacrylate, glycidyl α-ethyl acrylate, and 4-hydroxybutyl acrylate glycidyl ether. Among these, glycidyl methacrylate is preferable from the viewpoint of affinity and polymerizability with a structural unit derived from a monomer having a (meth)acryloyl group contained in a (meth)acrylic rubber.

In the (meth)acrylic rubber having a glycidyl group, a structural unit derived from a monomer having a glycidyl group and a structural unit derived from a monomer having a (meth)acryloyl group are included in the range not impairing the effect. It may contain a structural unit derived from another monomer. Examples of other monomers include aromatic vinyl monomers such as styrene, vinyltoluene, vinylxylene, chlorostyrene, bromstyrene, dichlorostyrene, α-methylstyrene; acrylonitrile, methacrylonitrile, acrylic acid, Methacrylic acid, acrylamide, methacrylamide, isoprene, butadiene, chloroprene, maleic anhydride, etc. may be mentioned.

The (meth)acrylic rubber having a glycidyl group can be obtained by polymerizing a monomer having a glycidyl group, a monomer having a (meth)acryloyl group, and a monomer contained as necessary.

At the time of polymerization, a polymerization initiator is usually used, preferably a radical polymerization initiator.
Examples of the radical polymerization initiator include organic peroxides such as benzoyl peroxide, di-tert-butyl peroxide, tert-butyl perbenzoate, cumene hydroperoxide, and methyl ethyl ketone peroxide; 2,2′-azobisiso Butyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 1,1'-azobiscyclohexane-1 -Organoazo catalysts such as carbonitrile and 2,2'-azobis(2-amidinopropane) hydrochloride; inorganic peroxides such as potassium persulfate, ammonium persulfate, potassium bromate and hydrogen peroxide; peroxides And a reducing agent such as ferrous sulfate.

The polymerization method is not particularly limited, but examples of the polymerization method include bulk polymerization, emulsion polymerization, suspension polymerization, and solution polymerization. Among these polymerization methods, solution polymerization is preferable. Examples of the organic solvent used in the solution polymerization include methyl ethyl ketone, ethyl acetate, toluene and the like.

The polymerization temperature is preferably 60°C or higher and 150°C or lower. The polymerization is preferably carried out under normal pressure or pressure. A chain transfer agent such as dodecyl mercaptan or lauryl mercaptan may be used for the purpose of adjusting the molecular weight of the obtained (meth)acrylic rubber.

The weight average molecular weight of the (meth)acrylic rubber having a glycidyl group is preferably 40,000 to 100,000, more preferably 50,000 to 90,000, and further preferably 55,000 to 80,000. When the weight average molecular weight of the (meth)acrylic rubber is not more than the upper limit, the fluidity of the resin composition is further improved and the moldability is improved, and cracks of a cured product obtained from the resin composition are effectively suppressed. it can. When the weight average molecular weight is not less than the lower limit value, it is expected that when used as a brake material binder, for example, the flexibility of rubber suppresses vibration absorption of the brake and solves the problem of brake squeal.

In the method for producing a phenol resin composition of the present invention, the phenol resin is modified with a (meth)acrylic rubber having a glycidyl group in the presence of 0.1% by mass to 2.0% by mass of water with respect to the above-mentioned phenol resin. Including steps.

When carrying out such modification, it is preferable to carry out in a molten state of the phenol resin. The melting temperature of the phenol resin is not particularly limited as long as the phenol resin can be melted, but is preferably 100°C or higher and 200°C or lower, more preferably 100°C or higher and 170°C or lower. Further, the melting of the phenol resin is preferably carried out under stirring from the viewpoint of the temperature uniformity of the whole resin.

A phenol resin is modified by adding a (meth)acrylic rubber having a glycidyl group to a phenol resin, typically a molten phenol resin, and mixing these. When carrying out this modification, 0.1% by mass to 2.0% by mass, preferably 0.1% by mass to 1.0% by mass, more preferably 0.3% by mass to 0. Denaturation is carried out in the presence of 8% by weight of water. By carrying out the modification under such a condition that an appropriate amount of water is present, it becomes easy to obtain a resin composition having an appropriate weight average molecular weight without producing a high molecular weight substance which significantly increases the viscosity. ..
The reason for this is unknown, but due to the presence of water in an appropriate amount during the mixing of the phenol resin and the (meth)acrylic rubber having a glycidyl group, the glycidyl group and the phenol resin contained in the (meth)acrylic rubber A reaction product of a (meth)acrylic rubber and a phenol resin, which has an appropriate molecular weight, is suppressed from excessively reacting with a functional group (for example, a phenolic hydroxyl group) to form a high molecular weight product. It is estimated that it is being generated.

There is no particular limitation on the method of adjusting the water content when performing the modification, but from the viewpoint of controlling the water content more reliably, the phenol resin in the dehydrated state and the (meth)acrylic rubber having a glycidyl group have a desired It is preferable to add water so that the amount of water becomes equal.

Dehydration of the phenol resin can be performed, for example, by melting the phenol resin as described above and then further reducing the pressure in the molten state. The depressurization condition is not particularly limited as long as the phenol resin can be dehydrated, but the degree of vacuum is preferably -90 kPa or more, more preferably -93 kPa or more from the viewpoints of suppressing deterioration of the phenol resin and productivity. The temperature for depressurization is not particularly limited as long as the phenol resin can be maintained in a molten state, but it is preferably 150°C or higher and 200°C or lower, more preferably 170°C or higher and 200°C or lower. Further, from the viewpoint that the dehydration from the phenol resin is surely performed in a shorter time, the dehydration of the phenol resin is preferably performed under stirring conditions.

The (meth)acrylic rubber having a glycidyl group may be added to the phenol resin, for example, the fully dehydrated (meth)acrylic rubber itself may be added to the phenol resin, but the addition is more quantitative. From the point of view of performing, it is preferable to add to the phenol resin as a solution containing a (meth)acrylic rubber having a glycidyl group and an organic solvent (hereinafter, simply referred to as a solution containing a (meth)acrylic rubber). Is.

When the (meth)acrylic rubber itself or a solution containing the (meth)acrylic rubber is added to the phenol resin, the (meth)acrylic rubber itself or the It is desirable that the solution containing the (meth)acrylic rubber does not contain water. When water is not contained in the (meth)acrylic rubber itself or the solution containing the (meth)acrylic rubber, after the phenol resin is dehydrated in a molten state, water is added to the melt in a desired amount. The (meth)acrylic rubber itself or a solution containing the (meth)acrylic rubber may be added to modify the phenol resin with the (meth)acrylic rubber having a glycidyl group. In the case of this method, the production of a high molecular weight substance is small, and a resin composition having a desired weight average molecular weight tends to be produced more reliably.

When a solution containing a (meth)acrylic rubber is added to the phenol resin, the solution containing the (meth)acrylic rubber obtained by the solution polymerization is used as it is, or a polymerization catalyst residue or the like is obtained from the solution obtained by the solution polymerization. It can also be used as the above solution after purification such as removal of

The temperature at which the (meth)acrylic rubber is added to the phenol resin is not particularly limited as long as the phenol resin and the (meth)acrylic rubber can be uniformly mixed, but preferably 100°C or higher and 200°C or lower, more preferably 100°C. It is 170°C or lower. In addition, the addition of the (meth)acrylic rubber to the phenol resin is preferably carried out under stirring conditions because the phenol resin and the (meth)acrylic rubber can be mixed more uniformly.

Then, the phenol resin is modified with a (meth)acrylic rubber having a glycidyl group in the presence of a predetermined amount of water. The modification can be performed, for example, by mixing a melt of a (meth)acrylic rubber having a glycidyl group and a phenol resin for a predetermined time. The mixing temperature of the (meth)acrylic rubber and the phenol resin at the time of modification is preferably 100° C. or higher and 200° C. or lower, more preferably 100° C. or higher and 170° C. or lower. The mixing time of the (meth)acrylic rubber and the phenol resin at the time of modification is not particularly limited as long as the (meth)acrylic rubber and the phenol resin can be uniformly mixed, but preferably 0.5 hours or more and 4 hours or less, More preferably, it is 1 hour or more and 3 hours or less.

When a phenolic resin modified with a (meth)acrylic rubber having a glycidyl group is produced, it has a glycidyl group relative to 100 parts by mass of the phenolic resin because it has a higher fluidity and the resulting cured product has better physical properties. The addition amount of the (meth)acrylic rubber is preferably 1 part by mass to 50 parts by mass, more preferably 5 parts by mass to 40 parts by mass, and further preferably 10 parts by mass to 30 parts by mass.

As described above, a phenol resin composition containing a phenol resin modified with a (meth)acrylic rubber having a glycidyl group is obtained.
Further, when the phenol resin is modified using a solution containing (meth)acrylic rubber, a step of removing the solvent may be included in order to remove the remaining organic solvent and the like. The desolvation is preferably carried out under reduced temperature conditions of preferably 150° C. or higher and 200° C. or lower, more preferably 160° C. or higher and 180° C. or lower, and a degree of vacuum of preferably −93 kPa or higher, more preferably −96 kPa or higher. This can be done by

The device for performing the step of modifying is not particularly limited, but each component can be charged, preferably a device capable of reducing pressure, melt mixing, etc., for example, equipped with a stirring blade, a jacket capable of heating and heat removal, Furthermore, a pressure-resistant reaction vessel with a vacuum device capable of reducing the pressure in the vessel can be used.

By the above-mentioned production method, a phenol resin composition containing a phenol resin modified with a (meth)acrylic rubber having a glycidyl group can be obtained. The phenol resin composition thus obtained has excellent fluidity and can suppress the occurrence of cracks in the cured product obtained from the resin composition. The weight average molecular weight of the modified phenolic resin contained in the resin composition is preferably 8,000 to 30,000, more excellent in fluidity and capable of further suppressing the generation of cracks in the obtained cured product. It is preferably 8,000 to 25,000, more preferably 8,000 to 20,000.

The above-mentioned method for producing a phenol resin composition may include a step of adding a curing agent. The curing agent can be added by, for example, kneading the phenol resin composition and the curing agent with a hot roll or the like.

Examples of the curing agent include amines such as hexamethylenetetramine; aldehydes such as paraformaldehyde and 1,3,5-trioxane; epoxy resins. Among these curing agents, hexamethylenetetramine is preferable.

In the method for producing the phenolic resin composition, a curing aid and a filler (for example, inorganic fine particles composed of calcium carbonate, calcium hydroxide, clay, talc, silica, aluminum oxide, or antimony trioxide, glass fiber, asbestos fiber). And the like), a step of adding other additives such as an inorganic fiber such as, vinylon, an organic fiber such as nylon, etc.), a foaming agent, a pigment, etc. to the resin composition.

Examples of the filler include inorganic fine particles made of an inorganic substance such as calcium carbonate, calcium hydroxide, clay, talc, silica, aluminum oxide, or antimony trioxide; inorganic fibers such as glass fiber and asbestos fiber; vinylon, nylon Examples include organic fibers made of organic substances such as

Further, the above-mentioned method for producing a phenol resin composition may include a step of pulverizing the phenol resin composition from the viewpoints of the subsequent handling property. The pulverization can be performed by a means for generally pulverizing the resin, for example, a high-speed rotary impact mill (ACM), a roller mill, a hammer mill, or the like.

The phenol resin composition obtained in the present invention is well kneaded with the above-mentioned curing agent (for example, hexamethylenetetramine) and the like using a hot roll or the like, and then finely pulverized to have a particle size of 200 mesh or less to obtain a resin composition. This resin composition powder can be used as various binders for shell molds, magnets, brake friction materials (brake linings), and the like.
When the phenol resin to be modified is a resole resin and the resulting resin composition is liquid, the phenol resin composition can be used as it is as various binders for shell molds, grindstones, brake friction materials (brake linings), etc. ..

The phenol resin composition obtained in the present invention is a casting material to which a curing agent (for example, hexamethylenetetramine) curing aid, a filler, a pigment and the like are further added, and which is poured into a mold or the like for use. Can also be used as

The phenolic resin composition obtained in the present invention further comprises a foaming agent (for example, dinitrosopentamethylenetetramine, azodicarbonamide, etc.) and, if necessary, a curing agent (for example, hexamethylenetetramine, etc.). It can also be used as a foam material capable of producing a foam by heat treatment.

The phenol resin composition obtained in the present invention is prepared by dissolving it in a solvent to prepare a solution, and using the solution in various substrates (for example, glass cloth, glass mat, asbestos paper, synthetic fiber mat, paper, cotton cloth, etc.). Can be used as a dry prepreg by removing the solvent. Further, the phenol resin composition of the present invention is dissolved in a solvent to prepare a varnish, which is optionally modified with tung oil, linseed oil, epoxy resin, furan resin, coumarone resin, etc. It can be used as a resin.
Examples of the solvent that can be used for these include alcohol solvents such as methyl alcohol, ethyl alcohol, butyl alcohol, octyl alcohol, 2-ethylhexyl alcohol, and nonyl alcohol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and isophorone. Solvents: ether solvents such as isopropyl ether, n-butyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ester solvents such as ethyl acetate, isobutyl acetate, n-butyl acetate, 2-ethylhexyl acetate, toluene, xylene, Examples thereof include aromatic solvents such as ethylbenzene; alicyclic solvents such as cyclohexane. These solvents may be used alone or in combination of two or more.

When the phenolic resin to be modified is a resole resin, a mixture (for example, suspension, latex, or solution) of the obtained phenolic resin composition and a solvent containing water is prepared, and a suitable acidic solution is added to the mixture. Add a substance (for example, benzol sulfonic acid, toluene sulfonic acid, phenol sulfonic acid, chloroalkyl sulfonic acid phosphate, hydrochloric acid, sulfuric acid, oxalic acid, etc.) as a curing agent and use it as an adhesive for heating or room temperature. You can

The phenol resin composition obtained in the present invention thus obtained is a molding material, a laminated material, a paint, an adhesive, a shell mold, a grindstone, various binders such as a brake friction material (brake lining), decoration, a tool, It can be used for various applications such as casting materials such as tableware or foam materials.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[Production Example 1] (Production of acrylic rubber having a glycidyl group)
82 parts by mass of n-butyl acrylate (manufactured by Toagosei Co., Ltd.), 2 parts by mass of glycidyl methacrylate (manufactured by Mitsubishi Gas Chemical Co., Inc.), and 25 parts by mass of ethyl acetate (manufactured by Showa Denko KK) were mixed to prepare a monomer solution. .. A catalyst solution was prepared by mixing 1 part by mass of 2,2′-azobis(2,4 dimethylvaleronitrile) (manufactured by Nippon Finechem Co., Ltd.) and 16 parts by mass of n-butyl acrylate (manufactured by Toagosei Co., Ltd.).
48 parts by mass of ethyl acetate was introduced into a flask equipped with a stirring blade so that the temperature in the flask was in the range of 80°C to 85°C. While maintaining the temperature, the monomer solution was uniformly added dropwise over 5 hours and the catalyst solution was added dropwise over 8 hours under stirring conditions. After the dropping was completed, the temperature inside the flask was kept in the range of 80°C to 90°C, and the polymerization reaction was continued for 30 minutes under stirring conditions. Then, the temperature in the flask was set to 60° C. or lower, and 2 parts by mass of phenol was added to stop the polymerization reaction.
After the termination of the polymerization reaction, the mixture was cooled to room temperature and ethyl acetate was added to the resulting solution to obtain a solution of acrylic rubber having a glycidyl group having a solid content of 53% by mass. The obtained glycidyl group-containing acrylic rubber had a weight average molecular weight of 75,000, and the obtained glycidyl group-containing acrylic rubber solution had a viscosity of 250 mPa·s.

[Example 1]
(Production of modified phenol resin block)
Into a device equipped with a stirrer, 100 parts by mass of Resintop PS-6367 (manufactured by Gunei Chemical Co., Ltd., polystyrene-equivalent weight average molecular weight: 4,000, free phenol 0.5%) was introduced as a novolac-type phenol resin, and stirred. It melted at 170° C. under the conditions. Next, the apparatus was depressurized to a vacuum degree of -96 kPa and held at a temperature of 155°C for 2 hours to dehydrate the water contained in the novolac type phenol resin. Thereafter, the pressure was returned to normal pressure, and 0.26 parts by mass of water (0.2% by mass with respect to the novolac type phenol resin) was added under stirring conditions at 155°C.
Then, 56 parts by mass of the acrylic rubber solution having a glycidyl group obtained in Production Example 1 (29.7 parts by mass as solid content) was added dropwise over 2 hours. During the dropping, the internal temperature was maintained at 130° C. or higher under stirring conditions. After completion of the dropping, the internal temperature was set to 160° C. under stirring conditions, the pressure was reduced to a vacuum degree of −93 kPa, and the pressure was maintained for 2 hours to remove ethyl acetate, phenol and the like. Then, it was cooled to room temperature to obtain a phenol resin block modified with an acrylic rubber having a glycidyl group.

(Preparation and pulverization of phenol resin composition)
12 parts by mass of hexamine was added to 100 parts by mass of a phenol resin mass modified with an acrylic rubber having a glycidyl group, and mixed at 25° C. using a roll. Then, the powder was obtained by pulverizing with a pulverizer until the passability of a sieve having a mesh size of 108 μm was 95% or more. The weight average molecular weight of the modified phenol resin and the flow of the phenol resin composition were evaluated under the following measurement conditions. The results are shown in Table 1.

(1) Measurement of weight average molecular weight The weight average molecular weight was determined by gel permeation chromatography (GPC) measurement under the following conditions.
Measuring device: GPC8220 (manufactured by Tosoh Corporation)
Column: TSK-G4000H (1 piece), TSK-G2500H (1 piece) and TSK-G2000H (2 pieces) connected in series in this order Solvent: tetrahydrofuran (THF)
Flow rate: 0.8 mL/min
Column temperature: 40°C
Sample concentration: 0.06g/10cc
Injection volume: 100 μL
Maximum detection sensitivity: 200 mV/min Detector: RI
Standard material: polystyrene (manufactured by Tosoh Corporation)

(2) Evaluation of flow The flow of the phenol resin composition was measured according to the "flow A method" described in Section 5.11.1 of JIS K6910.

(3) Evaluation of Crack Observation A phenol resin molding material having the following composition was pulverized and mixed by a pulverizer for 5 minutes, put into a mold, and preformed under conditions of room temperature, 30 MPa, and 1 minute. Next, this preform was transferred to another mold preheated to 150° C., and hot pressing was performed at 40 MPa and 150° C. for 10 minutes while removing generated gas. Then, after-curing was performed at 180° C. for 6 hours. The obtained molded product (pad) was used as a sample for measuring the amount of wear.
Barium titanate fiber (reinforcing fiber) 27.5 mass%
Copper fiber (reinforcing fiber) 15.0% by mass
Barium sulfate (inorganic filler) 27.0 mass%
Slaked lime (inorganic filler) 2.0 mass%
Cashew dust (organic filler) 8.0% by mass
Graphite (lubricant) 5.0% by mass
Iron oxide (abrasive) 7.0% by mass
Binder ^*1) 8.5 mass%
*1) Phenolic resin compositions obtained in Examples and Comparative Examples: x shows cracks by visual observation after hot pressing, ◯ shows cracks after after-curing, neither cracks are observed Was marked as ◎.

[Examples 2 to 7]
Production of a modified phenolic resin mass and the production of a resin composition in the same manner as in Example 1 except that the amount of water relative to the total amount of the novolac type phenolic resin and the acrylic rubber having a glycidyl group is changed to the conditions shown in Table 2. It was made and crushed. The weight average molecular weight of the obtained modified phenolic resin was measured and the flow of the phenolic resin composition was evaluated. The results are shown in Table 1.

[Comparative Example 1]
The modified phenol resin mass was produced, the resin composition was prepared and pulverized in the same manner as in Example 1 except that water was not added during the production of the modified phenol resin mass. The weight average molecular weight of the obtained modified phenolic resin was measured and the flow of the phenolic resin composition was evaluated. The results are shown in Table 1.

Claims (9)

A method for producing a phenol resin composition containing a phenol resin modified with a (meth)acrylic rubber having a glycidyl group,
A method for producing a phenol resin composition, wherein the step of modifying a phenol resin with a (meth)acrylic rubber having a glycidyl group is performed in the presence of 0.1% by mass to 2.0% by mass of water relative to the phenol resin. The (meth)acrylic rubber having a glycidyl group has a weight of a monomer mixture in which the content of the monomer having a glycidyl group is 0.5% by mass to 20% by mass based on all the monomers in the monomer mixture. The method for producing a phenolic resin composition according to claim 1, which is a united body. The method for producing a phenol resin composition according to claim 1, further comprising a step of pulverizing the phenol resin composition. The method for producing a phenol resin composition according to claim 1, wherein the phenol resin is a phenol novolac resin. Production of the phenolic resin composition according to any one of claims 1 to 4, wherein the modification is carried out in an amount of 1 part by mass to 50 parts by mass of the (meth)acrylic rubber having a glycidyl group with respect to 100 parts by mass of the phenolic resin. Method. The (meth)acrylic rubber having a glycidyl group has a weight ratio of the monomer mixture in which the content of n-butyl (meth)acrylate is 80% by mass to 99.5% by mass based on all the monomers in the monomer mixture. The method for producing the phenolic resin composition according to claim 1, wherein the phenolic resin composition is a united body. The method for producing a phenol resin composition according to any one of claims 1 to 6, wherein the monomer having a glycidyl group is glycidyl methacrylate. The method for producing a phenol resin composition according to any one of claims 1 to 7, wherein the (meth)acrylic rubber having a glycidyl group has a weight average molecular weight of 10,000 to 15,000. The method for producing a phenol resin composition according to claim 1, further comprising the step of adding a curing agent.