WO2011099259A1

WO2011099259A1 - Phenol resin composition, cured product thereof, and friction material

Info

Publication number: WO2011099259A1
Application number: PCT/JP2011/000658
Authority: WO
Inventors: 貴春阿部; 正信前田
Original assignee: 三井化学株式会社
Priority date: 2010-02-12
Filing date: 2011-02-07
Publication date: 2011-08-18
Also published as: JP2013079292A

Abstract

Provided is a phenol resin composition containing a phenol resin (II) and a copolymer (I) of an acrylic ester monomer and an alkenyl phenol monomer, wherein the copolymer (I) fulfils the following requirements (A), (B), and (C): (A) the weight ratio of the acrylic ester monomer and the alkenyl phenol monomer is 95/5 to 65/35 (former/latter); (B) the weight average molecular weight is 40000 to 90000 inclusive; and (C) the glass transition temperature is -10°C or lower.

Description

Phenolic resin composition, cured product thereof and friction material

The present invention relates to a phenol resin composition, a cured product thereof, and a friction material.

Phenolic resins have excellent mechanical properties, electrical properties, heat resistance, and adhesive properties, and binders for friction materials such as disc pads and drum brake linings, and electrical and electronic parts such as semiconductor encapsulants and laminates. It is used as a binder. On the other hand, phenolic resins are deficient in impact resistance and flexibility.

Non-asbestos type disc pads that do not use asbestos are widely used in Japan, Korea and North America due to carcinogenic problems. However, this putt has a very large number of complaints regarding squeal and judder (NVH: Noise, Vibration, Harsh). A phenomenon called morning squeal, in which a car starts from the garage when the temperature in the winter morning is low, and a large squeal or vibration occurs in the first few brakes, is particularly regarded as a problem. At this time, the driver suddenly brakes just by stepping on the brake lightly, and noise and vibration are generated. Similar cases occur not only in the morning but also after a long parking in the rain or in humid areas. In this problem, the water involved between the brake pads and the rotor has a very significant effect. Since it is almost impossible for the system to deal with such problems, it is necessary to impart low vibration absorption and high vibration absorption characteristics to the resin used in the pad in order to absorb or relieve noise and judder. .

In order to improve such characteristics, various modified phenol resins such as elastomer-modified phenol resins, oil-modified phenol resins, cashew-modified phenol resins, silicone-modified phenol resins, epoxy-modified phenol resins, and melamine-modified phenol resins have been studied.

Patent Document 1 describes a technique of mixing acrylonitrile-butadiene rubber (NBR) with a phenolic resin in order to improve impact resistance and flexibility. However, NBR in which these are mixed has a large particle size of 100 μm or more and is not compatible with phenolic resins. For this reason, the dispersibility of the mixed NBR is poor. Therefore, a large amount of NBR is required to obtain the effect of the above characteristics. However, when NBR increases, in mixed NBR, heat resistance deteriorates, and hygroscopicity deteriorates due to separation of the interface between the phenol resin phase and the NBR phase.

Also, there is a technique using an elastomer-modified phenol resin such as carboxy-terminated liquid NBR in order to improve the problem of dispersibility. In this technique, as the elastomer dissolved in the phenol resin is cured by the curing agent, the elastomer phase is spherically separated to add toughness. However, since phase separation at the time of curing is used, it is easily influenced by curing conditions such as the type of curing agent, temperature, time, etc., and stable cured product characteristics are difficult to obtain. Furthermore, since the interface between the phenol resin phase and the elastomer phase is separated, deterioration of hygroscopicity is inevitable.

In Patent Document 2, as a thermosetting resin composition that gives a cured product having excellent heat resistance, flexibility, and dimensional stability, a thermosetting comprising a copolymer containing isopropenyl phenol as one component and a phenol resin. Techniques related to the conductive resin composition are described. However, no specific study has been made on a resin composition that gives a cured product having excellent heat resistance, frictional sliding characteristics, and absorption vibration.

JP 60-184533 A JP 59-6246 A

An object of the present invention is to provide a phenol resin composition from which a cured product having excellent heat resistance, frictional sliding properties, and absorption vibration properties can be obtained.

The present invention is shown below.
[1]
A phenol resin composition comprising a copolymer (I) of an acrylate ester monomer and an alkenyl phenol monomer and a phenol resin (II),
The copolymer (I) is a phenol resin composition that satisfies the following requirements (A), (B), and (C).
(A) The weight ratio of the acrylate monomer / the alkenylphenol monomer is 95/5 to 65/35.
(B) The weight average molecular weight is 40000 or more and 90000 or less.
(C) The glass transition temperature is −10 ° C. or lower.
[2]
The phenol resin composition according to [1], wherein the copolymer (I) has a weight average molecular weight of more than 50000 and 90000 or less.
[3]
The phenol resin composition according to [1] or [2], wherein a weight ratio of the copolymer (I) / the phenol resin (II) is 5/95 to 50/50.
[4]
The phenol according to any one of [1] to [3], wherein the acrylate monomer includes at least one selected from the group consisting of ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. Resin composition.
[5]
The phenol resin composition according to any one of [1] to [4], wherein the alkenylphenol monomer is p-isopropenylphenol.
[6]
[1] to [5], further comprising 3 to 20 parts by weight of a curing agent with respect to a total of 100 parts by weight of the copolymer (I) and the phenol resin (II). Phenol resin composition.
[7]
Further comprising an additive having at least one selected from the group consisting of fibers, fillers, lubricants and abrasives;
The phenol resin composition according to [6], wherein a weight ratio of (the copolymer (I) + the phenol resin (II) + the curing agent) / the additive is 5/95 or more and 20/80 or less.
[8]
The phenol resin composition according to any one of [1] to [7], wherein the copolymer (I) has an ICI viscosity at 150 ° C of 1 Pa · s to 13 Pa · s.
[9]
The phenol resin composition according to any one of [1] to [8], which is used for a friction material.

[10]
A cured product obtained by curing the phenol resin composition according to any one of [1] to [9].
[11]
The cured product according to [10], wherein the weight retention when the mass after being left for 120 hours under a temperature of 300 ° C. in an air atmosphere is 50% or more.
[12]
[10] A friction material comprising the cured product according to [11].
[13]
The friction material according to [12], wherein a friction coefficient (Δμ) measured under the following measurement conditions is 0.145 or less.
[Measurement condition]
The coefficient of friction is a value obtained by subtracting the coefficient of friction (2) of the baseline check from the value of the coefficient of friction (1) when the coefficient of friction increases to the maximum.
Here, the friction coefficient (2) is obtained by cutting a sample and measuring it with an automotive standard JASO C 406 test method using a brake tester (曙 brake 1/10 scale tester), and then applying a braking initial speed of 10 km / h. Measurement is performed at a deceleration of 1.0 m / s ² , a braking interval of 60 seconds, and a braking frequency of 50 times. On the other hand, the friction coefficient (1) is measured under the same conditions as the friction coefficient (2) after leaving the sample for 24 hours at 30 ° C. and 80% RH humidity.

According to the present invention, it is possible to provide a phenol resin composition from which a cured product having excellent heat resistance, friction sliding properties and absorption vibration properties can be obtained.

The phenol resin composition of the present invention contains a copolymer (I) having a structure of an acrylate ester monomer and an alkenyl phenol monomer and a phenol resin (II).

(Copolymer (I))
As the acrylic acid ester monomer, an acrylic acid is used so that when the homopolymer of the acrylic acid ester monomer is homopolymerized to produce a homopolymer having a weight average molecular weight of 40000, the homopolymer has a glass transition temperature of −20 ° C. or lower. It is preferred to select an ester monomer. When such a monomer is selected, the glass transition temperature of the copolymer (I) can be easily controlled to −10 ° C. or lower. The copolymer (I) having a glass transition temperature of −10 ° C. or lower can be suitably used in a cold region, particularly in a North American region where the temperature often reaches −10 ° C.

Examples of acrylic acid ester monomers include ethyl acrylate, n-propyl acrylate, n-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-hexyl acrylate, and lauryl acrylate. These acrylic acid esters may be used alone or in combination of two or more. Among these, ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate are particularly preferable because they are easily available industrially and are inexpensive.

Alkenylphenol monomers include o-ethynylphenol, m-ethynylphenol, p-ethynylphenol, o-isopropenylphenol, m-isopropenylphenol, p-isopropenylphenol, 2- (1-propenyl) -1-hydroxy Benzene, 2- (2-propenyl) -1-hydroxybenzene, 3- (1-propenyl) -1-hydroxybenzene, 3- (2-propenyl) -1-hydroxybenzene, 4- (1-propenyl) -1 -Hydroxybenzene, 4- (2-propenyl) -1-hydroxybenzene, 2-ethynyl-1-hydroxynaphthalene, 4-ethynyl-1-hydroxynaphthalene, 5-ethynyl-1-hydroxynaphthalene, 6-ethynyl-1- Hydroxynaphthalene, 7-ethynyl-1-hy B carboxymethyl naphthalene, 8-ethynyl-1-hydroxy-naphthalene. Of these, industrially available p-isopropenylphenol is particularly preferred.

In the copolymer (I), the weight ratio of the acrylate ester monomer / alkenylphenol monomer is preferably 95/5 to 65/35, and particularly preferably 90/10 to 80/20 (hereinafter referred to as the following). , “To” means that an upper limit value and a lower limit value are included unless otherwise specified). When the weight ratio of the alkenylphenol monomers is less than 5, the crosslink density between the alkenylphenols and the phenol resin is lowered, and the heat resistance may be lowered. When the weight ratio of the alkenylphenol monomer exceeds 35, the glass transition temperature of the copolymer (I) exceeds −10 ° C., and the absorption vibration property in the low temperature region may be deteriorated.

The copolymer (I) of the present invention may contain structural units derived from monomers other than acrylic acid ester monomers and alkenylphenol monomers in an amount that does not impair the object of the present invention. The units derived from other monomers can be generally 0 to 10% by weight, preferably 0 to 5% by weight, when the weight of the copolymer (I) is 100% by weight.
Examples of other monomers include n-butyl methacrylate and glycidyl methacrylate.

As for the weight average molecular weight of the copolymer (I), the lower limit is preferably 40000 or more, more preferably more than 50000, and further preferably 55000 or more, while the upper limit is preferably 90000 or less. More preferably, it is 80000 or less, More preferably, it is 75000 or less. When the weight average molecular weight is less than 40,000, the viscosity of the copolymer is reduced, so that it is easy to aggregate, the contact area between the alkenylphenol and the phenol resin of the copolymer is small, and the curing reaction is difficult, and the heat resistance is May decrease. On the other hand, when the weight average molecular weight exceeds 90000, the viscosity increases and the fine dispersion of the copolymer (I) becomes easy due to shear stress. However, due to the high molecular weight, the molecules are easily entangled and difficult to move. Curing between the resins tends to proceed preferentially and the crosslink density increases, so that the resin is pulled by the characteristics of the phenolic resin and heat resistance is increased, but the absorption vibration property may be deteriorated. Therefore, by setting the weight average molecular weight of the copolymer (I) within the above range, the present invention excellent in heat resistance and absorption vibration can be obtained.
The ICI viscosity measured at 150 ° C. of the copolymer (I) is, for example, preferably from 1.0 to 13 Pa · s, more preferably from 1.0 to 10 Pa · s.

The glass transition temperature of the copolymer (I) is preferably −10 ° C. or less, preferably −15 ° C. or less, particularly preferably −20 ° C. or less. When the glass transition temperature is higher than −10 ° C., the absorption vibration property in the low temperature region is deteriorated.
That is, when the glass transition temperature of the copolymer (I) is increased, the damping ability at low temperature is deteriorated and the decay time is prolonged, so that the noise reduction effect at low temperature may be lost.

The molecular weight distribution (Mw / Mn) of the copolymer (I) can be 1.0 to 5.0, and preferably 2.0 to 4.0.

The copolymer (I) of the present invention is preferably a random copolymer because stable performance is easily obtained.

Next, the manufacturing method of copolymer (I) is demonstrated.
The copolymer (I) is obtained by reacting an acrylate ester monomer and an alkenylphenol monomer with a radical polymerization initiator, but is not particularly limited to this method.

Any initiator used in ordinary radical polymerization can be used. For example, azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, azobis-2-amidinopropane hydrochloride Salt, azobisisobutyric acid dimethyl, azobisisobutylamidine hydrochloride or 4,4′-azobis-4-cyanovaleric acid and other azo initiators, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, di-tert peroxide -Butyl, lauroyl peroxide, acetyl peroxide, diisopropyl dicarbonate, cumene hydroperoxide, tert-butyl hydroperoxide, dicumyl peroxide, p-menthane hydroperoxide, pinane hydroperoxide, methyl ethyl ketone peroxide , Peroxide initiators such as cyclohexanone peroxide, diisopropylperoxydicarbonate, tert-butylperoxylaurate, di-tert-butylperoxyphthalate, dibenzyloxide or 2,5-dimethylhexane-2,5-dihydroperoxide Or redox initiators such as benzoyl peroxide-N, N-dimethylaniline or peroxodisulfuric acid-sodium hydrogen sulfite. Among them, azo initiators or peroxide initiators are preferable, and azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, dimethyl azobisisobutyrate, benzoyl peroxide, 2,4 More preferred are dichlorobenzoyl peroxide, di-tert-butyl peroxide, lauroyl peroxide, diisopropyl dicarbonate peroxide or acetyl peroxide. The radical polymerization initiators can be used alone or in combination of two or more simultaneously or sequentially.

The amount of the radical polymerization agent used is preferably 0.1 to 15 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the total of acrylic acid ester monomers and alkenylphenol monomers. 1 to 5 parts by weight is particularly preferred. You may use so that the whole quantity or one part of a radical polymerization agent may be added at the time of a heating start or after a superheat start.

Rather than charging the monomer and catalyst all at once, it is more difficult for the copolymer to become a block polymer, and it is easier to obtain a random copolymer with stable performance and unreacted. This is preferable because of less monomer.

Any solvent can be used as long as it does not inhibit the reaction, but ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone or γ-butyrolactone, n-propyl alcohol, isopropyl alcohol, Alcohols such as n-butyl alcohol, tert-butyl alcohol, n-octanol, 2-ethylhexanol or n-dodecyl alcohol, glycols such as ethylene glycol, propylene glycol or diethylene glycol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol Dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether or tetra Ethers such as lofuran and dioxane, alcohol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether or diethylene glycol monomethyl ether, n-propyl formate, isopropyl formate, n-formate Esters such as butyl, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate, n-hexyl acetate, methyl propionate, ethyl propionate or methyl butyrate, -Methyl oxypropionate, ethyl 2-oxypropionate, n-propyl 2-oxypropionate, isopropyl 2-oxypropionate, 2-oxy-2-methylprop Monooxycarboxylic acid esters such as ethyl pionate or methyl 2-oxy-3-methylbutyrate, ethyl methoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate or methyl 3-ethoxypropionate Alkoxycarboxylic esters such as cellosolve acetate, methyl cellosolve acetate, cellosolve esters such as ethyl cellosolve acetate or butyl cellosolve acetate, aromatic hydrocarbons such as benzene, toluene or xylene, halogenation such as trichloroethylene, chlorobenzene or dichlorobenzene Amino acids such as hydrocarbons, dimethylacetamide, dimethylformamide, N-methylacetamide, N-methylpyrrolidone or N, N′-dimethylimidazolidinone And the like. These solvents may be used alone or in combination of two or more. Further, by using these solvents, a plurality of heterogeneous phases may be formed, but it is preferable that the reaction solution becomes a homogeneous phase.

The amount of the solvent used can be determined by the raw material used, the type and amount of the radical polymerization initiator, the molecular weight of the desired copolymer, and the like. Usually, the amount of the solvent used is preferably 5 to 5000 parts by weight, more preferably 10 to 3000 parts by weight, and particularly preferably 30 to 1000 parts by weight with respect to 100 parts by weight of the total raw materials used.

(Phenolic resin (II))
The phenol resin (II) is an alternating polymer of a phenol compound and a compound having a divalent linking group.

Phenol resins (II) are phenol novolac resins, residues obtained by removing bisphenol from novolacs, resol type phenol resins, phenol-dicyclopentadiene resins, phenol aralkyl resins, biphenyl aralkyl resins, naphthol aralkyl resins. , Aniline aralkyl resins and the like, but phenol novolac resins that are easily available and inexpensive are particularly preferred.

Next, the manufacturing method of phenol resin (II) is demonstrated.
The phenol resin (II) according to the present invention can be obtained, for example, by reacting a phenol compound and an aldehyde in the presence of an acid catalyst, but is not particularly limited to these methods.

Examples of the phenol compound used include phenol, o-cresol, m-cresol, and p-cresol. Preferably it is phenol. You may use these individually or in combination of 2 or more types.

Further, examples of the compound used as the compound of the two linking groups include aldehydes such as formaldehyde and paraformaldehyde. More preferred is formaldehyde. You may use these individually or in combination of 2 or more types. As a catalyst for reacting a phenol compound with aldehydes, metal salts such as zinc acetate, acids such as oxalic acid, hydrochloric acid, sulfuric acid, diethylsulfuric acid and paratoluenesulfonic acid can be used alone or in combination of two or more. Usually, the amount of the catalyst used is 0.01 to 5 parts by weight with respect to 100 parts by weight of the phenol compound.

(Phenolic resin composition)
The phenol resin composition of the present invention can be obtained by mixing the copolymer (I) and the phenol resin (II).

The weight ratio of copolymer (I) / phenolic resin (II) is preferably 5/95 to 50/50, more preferably 10/90 to 40/60, and particularly preferably 20/80 to 30/70. . When the weight ratio of the copolymer (I) is less than 5, the absorption vibration performance at a low temperature may be lowered. On the other hand, when the weight ratio of the copolymer (I) exceeds 50, the heat resistance may be lowered.
When the proportion of the copolymer (I) increases, the hardness and curability are improved, but the hygroscopicity may decrease because the amount of hydroxyl groups increases.

As a mixing method of the copolymer (I) and the phenol resin (II), a method of mixing in a powder form by pulverization, a method of melting and mixing at a temperature of 120 to 180 ° C. for several minutes to several hours, , Common solvents for copolymer (I) and phenol resin (II), for example, alcohols such as methanol, ethanol, propenol, benzyl alcohol, diacetone alcohol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone And a method of dissolving and mixing in one or more solvents such as ethers such as dioxane, tetrahydrofuran, methyl cellosolve and ethyl cellosolve, and esters such as ethyl acetate and butyl acetate.

The phenol resin composition of the present invention may contain a curing agent such as paraformaldehyde or hexamine as necessary. The content of the curing agent is preferably 3 to 20 parts by weight, and more preferably 5 to 15 parts by weight with respect to 100 parts by weight as a total of the copolymer (I) and the phenol resin (II).

Moreover, the phenol resin composition of the present invention may contain various additives.

As such a resin composition, for example, in addition to the copolymer (I), the phenol resin (II), and a curing agent, at least one additive selected from fibers, fillers, lubricants, and abrasives is used. You may contain. At this time, in the phenol resin composition of the present invention, the weight ratio of (copolymer (I) + phenol resin (II) + curing agent) / additive is 5/95 to 20/80, preferably 8/92. To 15/85.

Examples of fibers include aramid fibers, potassium titanate fibers, ceramic fibers, copper fibers, and glass fibers. Examples of the filler include inorganic fillers such as barium sulfate, mica, antimony trisulfide, and calcium hydroxide, and organic fillers such as cashew dust, rubber dust, and wood powder. Examples of the lubricant include graphite, antimony sulfide, molybdenum sulfide and the like. Examples of the abrasive include zirconium oxide and iron oxide.

Moreover, the phenol resin composition of the present invention may contain additives other than those described above, for example, a colorant, a flame retardant, a coupling agent and the like, if necessary.

(Hardened product of phenol resin composition)
The cured product of the present invention is obtained by curing the phenol resin composition. For example, the cured product of the present invention is obtained by curing a phenol resin composition containing the copolymer (I), the phenol resin (II) and a curing agent, and further various additives as necessary. Can do. By heating the phenol resin composition, a cross-linking reaction occurs between the copolymers (I), between the phenol resins (II), and between the copolymer (I) and the phenol resin (II). It is thought that it is formed.

In order to obtain the cured product of the present invention, for example, the phenol resin composition is filled in a mold or the like, and molded under conditions of 130 to 180 ° C. and 10 to 100 MPa by heating or compression molding for 5 to 20 minutes. Thereafter, post-curing treatment is preferably performed at 160 to 250 ° C. as necessary. Thus, a molded product is obtained from the cured product of the present invention.

The obtained molded product is excellent in heat resistance and sliding characteristics and excellent in vibration absorption (particularly absorption vibration at low temperature). Therefore, it can be used for applications such as industrial machinery, railway vehicles, luggage vehicles, and friction sliding materials for automobiles. The phenol resin composition of the present invention is particularly preferably used as a binder for friction materials such as disk pads and drum brake linings, and as a binder for electrical and electronic parts such as semiconductor encapsulants and laminates. Moreover, the hardened | cured material of this invention can be used for a friction material. Thus, according to the present invention, it is possible to provide a phenol resin composition from which a molded body (cured product) having excellent heat resistance, frictional sliding characteristics and absorption vibration properties can be obtained, which is extremely valuable industrially. Is expensive.

The upper limit of the weight retention rate of the cured product of the present invention is not particularly limited, but can be, for example, 90% or less, more preferably 80% or less. For example, the lower limit of the weight retention is preferably 50% or more, and more preferably 55% or more. This weight retention rate can represent the heat resistance of the cured product of the present invention. Further, the weight retention can be adjusted by the copolymer (I) according to the present invention, the ICI viscosity, and the like.

The upper limit value of the friction coefficient (Δμ) of the cured product (friction material) of the present invention is, for example, preferably 0.145 or less, and more preferably 0.135 or less. The lower limit value of the friction coefficient is not particularly limited, but may be, for example, 0.100 or more, and more preferably 0.110 or more. This coefficient of friction can represent the hygroscopicity (friction sliding property) of the cured product of the present invention. Further, the friction coefficient includes the weight ratio of the acrylate ester monomer and the alkenylphenol monomer in the copolymer (I) according to the present invention, the weight ratio of the copolymer (I) and the phenol resin (II), etc. Can be adjusted.

The upper limit value of the required time (Δmsec.) Required for vibration attenuation, which represents the absorption vibration property of the cured product (friction material) of the present invention, is preferably 0.55 or less, and more preferably 0.50 or less. Although the lower limit of required time ((DELTA) msec.) Is not specifically limited, For example, it can be set to 0.20 or more, and can be set to 0.30 or more. This coefficient of friction can represent the hygroscopicity of the cured product of the present invention. The absorption vibration property can be adjusted by the glass transition temperature in the copolymer (I) according to the present invention, the weight average molecular weight of the copolymer (I), and the like.

(Production Example 1)
A reactor equipped with a stirrer, a reflux condenser and a thermometer was charged with 35 g of methyl ethyl ketone, and the temperature was raised while stirring. When methyl ethyl ketone began to reflux, dropwise addition of a solution prepared by mixing 95 g of ethyl acrylate, 5 g of p-isopropenyl phenol and 20 g of methyl ethyl ketone was started, and the reaction was carried out under reflux of methyl ethyl ketone. During this time, a solution in which 1 g of azobis-2,4-dimethylvaleronitrile as a catalyst was mixed with 5 g of methyl ethyl ketone was added in several portions. The dropwise addition was completed in 3 hours under reflux, and after completion of the dropwise addition, the reaction was further aged for 30 minutes. Thereafter, the reaction was further carried out while adding a solution prepared by mixing 1 g of azobis-2,4-dimethylvaleronitrile with 5 g of methyl ethyl ketone in several portions. After completion of the reaction, unreacted monomers and solvent were removed to obtain a copolymer having a weight average molecular weight (Mw) of 58000 and a glass transition temperature (Tg) of -21 ° C. The results are shown in Table 1.

(Production Example 2)
The same procedure as in Production Example 1 was carried out except that 95 g of ethyl acrylate and 5 g of p-isopropenylphenol were used instead of 80 g of n-butyl acrylate and 20 g of p-isopropenylphenol. The weight average molecular weight was 62000 and Tg was − A copolymer having a temperature of 20 ° C. was obtained. The results are shown in Table 1.

(Production Example 3)
A copolymer having a weight average molecular weight of 75,000 and Tg of −12 ° C. was obtained in the same manner as in Production Example 2, except that n-butyl acrylate was changed to 70 g and p-isopropenylphenol was changed to 30 g. The results are shown in Table 1.

(Production Example 4)
A copolymer having a weight average molecular weight of 58000 and a Tg of −33 ° C. was obtained in the same manner as in Production Example 2 except that 95 g of n-butyl acrylate and 5 g of p-isopropenylphenol were used. The results are shown in Table 1.

(Production Example 5)
A copolymer having a weight average molecular weight of 49000 and a Tg of −36 ° C. was obtained in the same manner as in Production Example 2, except that n-butyl acrylate was changed to 90 g and p-isopropenylphenol was changed to 10 g. The results are shown in Table 1.

(Production Example 6)
The same procedure as in Production Example 1 was carried out except that 95 g of ethyl acrylate and 5 g of p-isopropenylphenol were used, and 80 g of 2-ethylhexyl acrylate and 20 g of p-isopropenylphenol were used. The weight average molecular weight was 47000 and Tg was − A copolymer having a temperature of 40 ° C. was obtained. The results are shown in Table 1.

(Comparative Production Example 1)
The same procedure as in Production Example 2, except that the amount of azobis-2,4-dimethylvaleronitrile added was changed to 20 g (10 g before aging, 10 g after aging), and the weight average molecular weight was 15000 and Tg was −23 ° C. A copolymer was obtained. The results are shown in Table 1.

(Comparative Production Example 2)
A copolymer having a weight average molecular weight of 62000 and a Tg of −35 ° C. was obtained in the same manner as in Production Example 2, except that n-butyl acrylate was changed to 98 g and p-isopropenylphenol was changed to 2 g. The results are shown in Table 1.

(Comparative Production Example 3)
The same procedure as in Production Example 2, except that the amount of azobis-2,4-dimethylvaleronitrile added was changed to 0.05 g (0.025 g before aging, 0.025 g after aging), and the weight average molecular weight was 102000, Tg A copolymer having a temperature of −20 ° C. was obtained. The results are shown in Table 1.

(Comparative Production Example 4)
A copolymer having a weight average molecular weight of 65000 and a Tg of 3 ° C. was obtained in the same manner as in Production Example 2, except that n-butyl acrylate was changed to 60 g and p-isopropenylphenol was changed to 40 g. The results are shown in Table 1.

(Comparative Production Example 5)
The same procedure as in Production Example 1 was conducted except that 95 g of ethyl acrylate and 5 g of p-isopropenylphenol were used, and 90 g of n-butyl acrylate and 10 g of α-methylstyrene were used. The weight average molecular weight was 69000 and Tg was −30. A copolymer having a temperature of 0 ° C. was obtained. The results are shown in Table 1.

(Comparative Production Example 6)
A copolymer having a weight average molecular weight of 54000 and Tg of −20 ° C. was obtained in the same manner as in Comparative Production Example 5 except that n-butyl acrylate was changed to 80 g and α-methylstyrene was changed to 20 g. The results are shown in Table 1.

In the production examples and comparative production examples, the weight average molecular weight (Mw), number average molecular weight (Mn) and ICI viscosity of the copolymer were measured by the following methods. The results are shown in Table 1.

[Molecular weight: weight average molecular weight (Mw), number average molecular weight (Mn)]
The GPC method was performed under the following conditions.
Measuring instrument: GPC8220 (manufactured by Tosoh Corporation)
Column: TSK-G4000H (1), TSK-G2500H (1) and TSK-G2000H (2) were connected in series in this order.
Solvent: tetrahydrofuran (THF)
Flow rate: 0.8mL / 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 (Tosoh Corporation)

[ICI viscosity]
The ICI viscosity at 150 ° C. was measured using an ICI cone plate viscometer.

The Tg of the copolymer was measured by the method described later.
Example 1

[Production of phenolic resin composition]
A reactor equipped with a stirrer and a thermometer was charged with 100 g of a novolak type phenol resin (trade name: NVG2000, manufactured by Gunei Chemical Co., Ltd.) and heated to 150 to 170 ° C., and then the co-polymer obtained in Production Example 1 was used. A solution prepared by dissolving 30 g of the polymer in a solvent (methyl ethyl ketone) was dropped into the reactor over 1 hour. Next, the reaction was further carried out for 1 hour while distilling off the solvent. Thereafter, the solvent and the like were removed under reduced pressure to obtain a phenol resin composition.

[Adjustment of sample for weight retention and absorption vibration measurement]
100 g of the phenol resin composition and 12 g of hexamine as a curing agent were mixed and pulverized, and heated at 150 ° C. for 10 minutes to produce a molded product (a cylinder having a diameter of 50 mm and a height of 3.5 mm).
Thereafter, after-curing at 150 ° C. for 6 hours was used as a sample for measuring weight retention and absorption vibration.

[Adjustment of friction coefficient and Tg measurement sample]
A resin composition having the following composition was pulverized and mixed for 5 minutes with a pulverizer, placed in a mold, and preformed under conditions of room temperature, 30 MPa, and 1 minute. Next, this preform is transferred to another mold preheated to 150 ° C., and while being removed of the generated gas, it is hot-pressed at 30 MPa and 150 ° C. for 10 minutes, and then after-curing at 180 ° C. for 6 hours. The molded product (pad) thus obtained was used as a sample for measuring the coefficient of friction and Tg.

Potassium titanate fiber (reinforcing fiber) 27.5% by weight
Copper fiber (reinforced fiber) 15.0% by weight
Barium sulfate (inorganic filler) 27.0% by weight
Slaked lime (inorganic filler) 2.0% by weight
Cashew dust (organic filler) 8.0% by weight
Graphite (lubricated, abrasive) 5.0% by weight
Iron oxide (lubricated, abrasive) 7.0% by weight
Binder ^{* 1)} 8.5% by weight
* 1) The above phenol resin composition: hexamine (curing agent) = 100: 2 (mass ratio)

[Measurement method of each physical property]
Measurement was performed by the following method using the measurement sample. The results are shown in Table 1.

(1) Glass transition temperature (Tg) derived from copolymer (I)
The measurement was performed under the following conditions using a solid viscoelasticity measuring device TA (RSA). The measurement temperature range is -100 to 400 ° C, and the heating rate is 3 ° C / min. The measurement mode was a bending mode (Auto tension, Auto strain control), and the measurement frequency was 1 Hz. )

(2) Weight retention The mass after being left for 120 hours at a temperature of 300 ° C. in an air atmosphere was measured, and the weight retention was calculated based on the following formula.
Weight retention [mass%] = 100 × (W1-W2) / W1
W1: Sample mass before standing in a temperature of 300 ° C. and air atmosphere W2: Sample weight after standing in a temperature of 300 ° C. and air atmosphere for 120 hours (evaluation criteria)
○: 50% ≦ weight retention Δ; 45% ≦ weight retention <50%
×; Weight retention <45%

(3) Friction coefficient A sample is cut out and measured with the automotive standard JASO C 406 test method using a brake tester (曙 brake 1/10 scale tester), then the initial braking speed is 10 km / h and the braking deceleration is 1.0 m / h. The baseline of the coefficient of friction was measured at s ² , a braking interval of 60 seconds and a braking frequency of 50 times. The test product was allowed to stand at 30 ° C. and 80% RH for 24 hours, and the friction coefficient under the above conditions was measured again using a brake tester.
The coefficient of friction was calculated by subtracting the coefficient of friction of the baseline check from the value of the coefficient of friction when it increased to the maximum.
(Evaluation criteria)
○: Friction coefficient ≦ 0.145Δμ
Δ: 0.145Δμ <friction coefficient ≦ 0.160Δμ
×: 0.160Δμ <Friction coefficient

(4) Absorbing vibration property Using an FFT analyzer measuring machine (Oros 34) in an atmosphere of 20 ° C and -20 ° C, the test piece is vibrated with a hammer, and the acceleration is from 150 m / s ² to 50 m / s ² The time required for decay was calculated, and the value obtained by subtracting the time required under the 20 ° C. condition from the time required under the −20 ° C. condition was indicated.
(Evaluation criteria)
○: Absorbing vibration property ≦ 0.55 Δmsec.
Δ: 0.55 Δmsec. <Absorptive vibration property ≦ 0.75 Δmsec.
×: 0.75 Δmsec. <Absorption vibration

(Examples 2 to 7, Comparative Examples 1 to 7)
It carried out similarly to Example 1 except having replaced with the copolymer obtained in manufacture example 1, and manufacturing the phenol resin composition using the copolymer of Table 1. The results are shown in Table 1.

The addition amount shown in Table 1 represents parts by weight of the copolymer with respect to 100 parts by weight of the phenol resin. * 1 shown in Table 1 is acrylonitrile (20% by mass) -n-butyl acrylate (65% by mass) -n-butyl methacrylate (8% by mass) -p-isopropenylphenol (8% by mass) Represents a copolymer.

As is apparent from the results in Table 1, it was found that the molded product produced from the phenol resin composition of the present invention had excellent heat resistance, frictional sliding properties, and absorption vibration properties.

This application claims priority based on Japanese Patent Application No. 2010-28533 filed on Feb. 12, 2010, the entire disclosure of which is incorporated herein.

Claims

A phenol resin composition comprising a copolymer (I) of an acrylate ester monomer and an alkenyl phenol monomer and a phenol resin (II),
The copolymer (I) is a phenol resin composition that satisfies the following requirements (A), (B), and (C).
(A) The weight ratio of the acrylate monomer / the alkenylphenol monomer is 95/5 to 65/35.
(B) The weight average molecular weight is 40000 or more and 90000 or less.
(C) The glass transition temperature is −10 ° C. or lower.
The phenol resin composition according to claim 1, wherein the copolymer (I) has a weight average molecular weight of more than 50000 and 90000 or less.
3. The phenol resin composition according to claim 1, wherein a weight ratio of the copolymer (I) / the phenol resin (II) is 5/95 to 50/50.
The phenol resin composition according to any one of claims 1 to 3, wherein the acrylate monomer includes at least one selected from the group consisting of ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. object.
The phenol resin composition according to any one of claims 1 to 4, wherein the alkenylphenol monomer is p-isopropenylphenol.
The phenol according to any one of claims 1 to 5, further comprising 3 to 20 parts by weight of a curing agent, based on a total of 100 parts by weight of the copolymer (I) and the phenol resin (II). Resin composition.
Further comprising an additive having at least one selected from the group consisting of fibers, fillers, lubricants and abrasives;
The phenol resin composition according to claim 6, wherein a weight ratio of (copolymer (I) + phenol resin (II) + curing agent) / additive is 5/95 or more and 20/80 or less.
The phenol resin composition according to any one of claims 1 to 7, wherein the copolymer (I) has an ICI viscosity at 150 ° C of 1 Pa · s to 13 Pa · s.
The phenol resin composition according to any one of claims 1 to 8, which is used for a friction material.
A cured product obtained by curing the phenol resin composition according to any one of claims 1 to 9.
The hardened | cured material of Claim 10 whose weight retention is 50% or more when measuring the mass after leaving it for 120 hours in temperature 300 degreeC and an air atmosphere.
A friction material comprising the cured product according to claim 10 or 11.
The friction material of Claim 12 whose friction coefficient ((DELTA) micro) measured on the following measurement conditions is 0.145 or less.
[Measurement condition]
The coefficient of friction is a value obtained by subtracting the coefficient of friction (2) of the baseline check from the value of the coefficient of friction (1) when the coefficient of friction increases to the maximum.
Here, the friction coefficient (2) is obtained by cutting a sample and measuring it with an automotive standard JASO C 406 test method using a brake tester (曙 brake 1/10 scale tester), and then applying a braking initial speed of 10 km / h. Measurement is performed at a deceleration of 1.0 m / s 2 , a braking interval of 60 seconds, and a braking frequency of 50 times. On the other hand, the friction coefficient (1) is measured under the same conditions as the friction coefficient (2) after leaving the sample for 24 hours at 30 ° C. and 80% RH humidity.