JPH0931441A - Friction agent composed of highly reactive modified phenolic resin and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a friction agent excellent in high temperature stability (heat resistance) and capable of giving a friction material having a friction coefficient stable in terms of temperature and speed, and excellent in abrasion resistance, bending strength and shock strength under high temperature when used in combination with a friction base material by using a new highly reactive modified phenolic resin as a binder. SOLUTION: (1) This friction material is composed of (A) a highly reactive modified phenolic resin obtained by lowering the molecular weight of a modified phenolic resin by a phenol in the presence of an acid catalyst, (B) a binder consisting of an epoxy resin and a hardener and/or a hardening accelerator (D), and (C) a friction base material. (2) The highly reactive modified phenolic resin (A), the epoxy resin (B), and the hardener and/or the hardening accelerator (D) are mixed with a friction base material (C), and the mixture is subjected to heat pressure molding at 150-300 deg.C under 10-230kg/cm<2> . (3) A solution containing the highly reactive modified phenolic resin (A), the epoxy resin (B), the hardener and/or the hardening accelerator (D) is prepared. Then, the obtained solution is impregnated into a friction material (C), and it is subjected to heat pressure molding at 150-300 deg.C under 10-230kg/cm<2> after dried.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel and useful highly reactive modified phenolic resin-based friction material and a method for producing the same. More specifically, the present invention relates to a novel highly reactive modified phenolic resin obtained by lowering the molecular weight of a modified phenolic resin obtained from petroleum heavy oils or pitches with phenols as a binder for friction materials. The present invention relates to a novel highly reactive modified phenolic resin-based friction material as an essential component and a method for producing the same. More specifically, since the friction material of the present invention uses a novel highly reactive modified phenolic resin, it has excellent high temperature stability (heat resistance) and, in combination with the use of a friction base material, friction against temperature and speed. The coefficient is stable, and it has excellent wear resistance at high temperatures, bending strength, and impact strength.

[0002]

2. Description of the Related Art Conventionally, friction materials such as clutch facings are made by binding a friction base material mainly composed of inorganic fibers such as glass fibers and asbestos fibers with a synthetic resin binder, and are particularly used. The binding agent plays an important role. As the binder, those based on various phenolic resins have been developed. For example, aromatic hydrocarbon-formaldehyde polycondensate is reacted with a fusible / soluble bifunctional alkylphenol-formaldehyde polycondensate to produce a product thereof. Modified phenolic resin obtained by further reacting formaldehyde with (JP-A-53-108197), phenolic resin modified with an aromatic hydrocarbon resin and a triazine-based compound (JP-A-58-217577), aromatic Techniques such as a resin composition containing a novolac phenol resin modified with a group hydrocarbon resin, a cyanate compound, and hexamethylenetetramine (JP-A-60-31585) are known.

[0003]

However, these binders for friction materials are excellent in any one of excellent characteristics such as wear resistance and frictional characteristics at a relatively high temperature and good moldability. In the present situation, a friction material having a good balance, such as that the characteristics of No. 1 are not always good, has not been obtained. In addition, there is no known friction material with excellent durability at high heat generated during high-speed operation, especially wear resistance, and excellent mechanical strength and formability (impregnability), and there is a strong demand for it. Met.

[0004]

Means for Solving the Problems As a result of various studies on the above problems, the present inventors have found that a modified phenolic resin obtained from a petroleum heavy oil or pitch as a raw material is used as a binder for a friction material. By using a new highly reactive modified phenolic resin with a low molecular weight, it has excellent stability at high temperature (heat resistance) and, in combination with the use of a friction base material, the friction coefficient with respect to temperature and speed is stable, They have found that they are excellent in wear resistance at high temperatures, bending strength, and impact strength, and have completed the present invention.

That is, the present invention: (A) a modified phenolic resin obtained by polycondensing a heavy petroleum oil or pitches, a formaldehyde polymer and a phenol in the presence of an acid catalyst is used as an acid catalyst. Provided is a highly reactive modified phenolic resin-based friction material containing a binder comprising a highly reactive modified phenolic resin having a low molecular weight of phenols in the presence of (B) an epoxy resin, and (C) a friction base material. . It is also characterized in that the binder further contains a curing agent and / or a curing accelerator (D). It is also characterized in that the friction base material (C) is a reinforcing fiber and a friction modifier. Also,

A highly reactive modified phenolic resin (A), an epoxy resin (B), a curing agent and / or a curing accelerator (D) are mixed with a friction base material (C), and the temperature is 150 to 300.
Provided is a method for producing a highly reactive modified phenolic resin-based friction material, which comprises hot-pressing at a temperature of 10 to 230 kg / cm ² and optionally post-baking at 130 to 250 ° C. In addition, a solution containing a highly reactive modified phenolic resin (A), an epoxy resin (B), and a curing agent and / or a curing accelerator (D) is prepared, and the friction base material (C) is impregnated with the solution and dried. After that, shaping is performed, temperature is 150 to 300 ° C., pressure is 10 to 230.
After thermocompression molding at kg / cm ² , 130-
Provided is a method for producing a highly reactive modified phenolic resin-based friction material which is post-baked at 250 ° C.

Hereinafter, the present invention will be described in detail. (1) Binder (i) In the present specification, heavy petroleum oils or pitches, formaldehyde polymer and phenols,
The reaction product obtained by polycondensation in the presence of an acid catalyst is referred to as "modified phenol resin", and modified phenol resin having a low molecular weight with phenols used as a binder in the present invention is referred to as "highly reactive modified phenol." They are referred to as "resins" and they are usually used free of impurities through purification steps. Highly reactive modified phenolic resin (A) used in the present invention
Is basically produced by a method comprising lowering the molecular weight of a modified phenolic resin obtained in a specific polycondensation step by a lowering step of a phenol with a specific condition.

The friction material binder of the present invention is most characterized in that the highly reactive modified phenolic resin (A) is used as an essential component. The friction material binder of the present invention is characterized by blending the highly reactive modified phenolic resin (A) and the epoxy resin (B) described below, and does not impair the function of the highly reactive modified phenolic resin. Thermosetting resins such as various phenolic resins known as binders for friction materials may be blended in a small amount within the range. Of course, if necessary, a curing agent, a curing accelerator (D) and various additives described below may be added to the friction material binder in advance.

(1) Production of Modified Phenolic Resin The highly reactive modified phenolic resin (A) according to the present invention is obtained by subjecting the modified phenolic resin obtained in a specific polycondensation step to a molecular weight reduction step under specific conditions. It is manufactured by lowering the molecular weight.
The method for producing the modified phenolic resin is described in Japanese Patent Application No. 5-40.
It is desirable to carry out by the method described in No. 646,
The details are as follows.

Modified phenol resin and method for producing the same The modified phenol resin raw material used in the present invention is obtained by polycondensing heavy petroleum heavy oils or pitches shown below, phenols and formaldehyde polymer in the presence of an acid catalyst. To be

(B) Petroleum-based heavy oils or pitches It is necessary to use petroleum-based heavy oils or pitches as a raw material. The petroleum heavy oils or pitches have an aromatic hydrocarbon fraction fa value and an aromatic ring hydrogen content Ha value of
It is desirable to use the one shown in the following formula.

[Equation 1] (The fa value can be determined by ¹³ C-NMR,
The a value can be determined by ¹ H-NMR. ) The aromatic hydrocarbon fraction fa value is 0.40 to 0.95,
Preferably 0.5 to 0.8, more preferably 0.55
˜0.75 and the aromatic ring hydrogen content Ha value is 20 to 80.
%, Preferably 25-60%, more preferably 25-
Desirably, it is 50%.

The petroleum heavy oils or pitches as raw materials are
The number of condensed rings of the aromatic hydrocarbon constituting this is not particularly limited, but it is preferably a condensed polycyclic aromatic hydrocarbon mainly having 2 to 4 rings. In the case of a condensed polycyclic aromatic hydrocarbon having five or more rings, the boiling point exceeds 450 ° C. in most cases, so that it is difficult to collect those having a narrow boiling point range and the quality is not stable. The heavy petroleum-based oils or pitches used as raw materials are
It is obtained as a distillation residual oil of crude oil, a hydrogenolysis residual oil, a catalytic cracking residual oil, a thermal decomposition residual oil of naphtha or LPG and a vacuum distillate of these residual oils, an extract by solvent extraction or a heat-treated product. From these, the fa value and H
It is preferable to select and use a suitable a value.

(B) Formaldehyde polymer As the formaldehyde polymer as a raw material, there can be mentioned linear polymer such as paraformaldehyde, polyoxymethylene (particularly, oligomer) and cyclic polymer such as trioxane. The mixing ratio of heavy petroleum oils or pitches (a) and formaldehyde polymer (b) is
The number of moles of the formaldehyde polymer in terms of formaldehyde is 1 to 15, preferably 2 to 12, and more preferably 3 to 11 per 1 mole of the average number of moles calculated from the average molecular weight of heavy petroleum oils or pitches. I need to be there. If the mixing ratio is less than 1, it may not be possible to obtain a laminate having sufficient strength, which is not preferable. On the other hand, when the mixing ratio is more than 15, the performance of the resulting laminate and the yield of the modified phenol resin are almost unchanged, so it is considered useless to use more formaldehyde polymer. Further, the excess formaldehyde polymer may hinder the molecular weight reduction of the modified phenol resin in the molecular weight reduction step described later.

(C) Phenols Examples of phenols as raw materials include phenol, cresol, xylenol, resorcin, catechol, hydroquinone, bisphenol A, bisphenol F and α-.
One or more phenolic compounds selected from the group of naphthol and β-naphthol can be mentioned. The amount of phenols added is 0.3 to 5, preferably 0.5 to 3, as the number of moles of phenols per 1 mole of the average number of moles calculated from the average molecular weight of heavy petroleum oils or pitches. I need to be there.

If the amount added is less than 0.3, the reactivity of heavy petroleum oils or pitches with formaldehyde will be inferior to that of phenols with formaldehyde, so a sufficient crosslinking density will be obtained. Therefore, a laminated board having sufficient strength cannot be obtained. In particular, it has a low impact resistance and tends to be brittle. On the other hand, the amount of phenols added is 5
If it exceeds, the modification effect due to the modification of the phenol resin tends to be small.

Phenols are preferably added sequentially by a method such as dropping. The rate of addition is from 0.05 to 5% by weight, preferably 0.1 to 2% by weight, based on the total weight of the reaction mixture. The timing for starting the addition of the phenols is not particularly limited, but the timing for starting the addition may be the time at which the reaction between the petroleum heavy oil or pitches and formaldehyde has not substantially progressed. In practice, from the state in which the reaction rate of formaldehyde estimated from the amount of remaining free formaldehyde is substantially 0,
It is desirable to start the sequential addition of phenols at the time of 0% or less, preferably 50% or less.

(D) Acid catalyst As the acid catalyst, a Bronsted acid or a Lewis acid can be used, but a Bronsted acid is preferably used. As the Bronsted acid, toluenesulfonic acid,
Xylene sulfonic acid, hydrochloric acid, sulfuric acid, formic acid and the like can be used, but p-toluene sulfonic acid and hydrochloric acid are particularly excellent.
The amount of the acid catalyst used is 0.1 to 30% by weight, preferably 1 to 30% by weight based on the total amount of the petroleum heavy oil or pitches, the formaldehyde polymer and the phenols, which are raw materials for production.
It is 20% by weight.

(V) Reaction conditions In order to produce a modified phenolic resin in the polycondensation step using the above raw materials and catalysts, for example, petroleum heavy oils or pitches and formaldehyde polymer should be in the above proportions. It is preferable that the mixture is heated and stirred in the presence of an acid catalyst, and phenols are successively added to the mixture until the above ratio is reached to polycondense these raw materials. At that time, the reaction temperature is 50 to 160 ° C, preferably 60 to 120 ° C. The reaction temperature is determined in consideration of the raw material composition, the reaction time, the properties of the resin produced, and the like. Reaction time is 0.5-10
Hours, preferably 1 to 5 hours. The reaction time is determined in consideration of the raw material composition, the reaction temperature, the addition rate of phenols, the properties of the resin to be formed, and the like.

When the reaction is carried out batchwise, it can be carried out in one step, and preferably carried out in one step. In addition, when the continuous method is used, it is not necessary to use a device that is difficult to control, such as continuously mixing two or more kinds of reaction products, which are used in the conventional modified phenol resin, in a fixed amount, and the intermediate portion is used. A reaction vessel of a complete mixing type may be placed, and the phenols to be added may be fed into the reaction vessel in fixed amounts.
Such a device is relatively inexpensive and has good operability.

In the present invention, such a polycondensation reaction can be carried out without a solvent, but in that case, it is necessary to pay attention to the uniformity of the reaction. A suitable solvent may be used to reduce the viscosity of the reaction system so that a uniform reaction may occur.
The solvent is not particularly limited, but is, for example, aromatic hydrocarbon such as benzene, toluene, xylene;
Halogenated aromatic hydrocarbons such as chlorobenzene; Nitrated aromatic hydrocarbons such as nitrobenzene; Nitrated aliphatic hydrocarbons such as nitroethane and nitropropane; Halogenated fats such as perkrene, trichlene and carbon tetrachloride Examples thereof include group hydrocarbons.

Step of Purifying Modified Phenolic Resin The highly reactive modified phenolic resin according to the present invention is prepared by lowering the molecular weight of the modified phenolic resin obtained by the polycondensation reaction in the lowering molecular weight step according to the method of the present invention. it can. However, in the modified phenol resin obtained by the polycondensation step, in addition to the target modified phenol resin, an acid catalyst, unreacted components, reaction solvent, and the like may remain, and these are low molecular weight reaction. It affects the reaction conditions and the amount of raw materials, catalysts, etc. involved in the reaction. For example, when the modified phenol resin used in the step of lowering the molecular weight contains a large amount of a formaldehyde polymer which is a crosslinking agent as an unreacted component, a modified phenol resin,
The polycondensation reaction of the formaldehyde polymer and the phenols may precede the inhibition of lowering the molecular weight.

Therefore, in order to suitably set the reaction conditions in the low molecular weight reduction step so that the modified phenolic resin can efficiently reduce the low molecular weight by the reaction between the modified phenol resin and the phenols, it is necessary to use in the low molecular weight reduction step. It is desirable that the modified phenolic resin obtained does not contain an acid catalyst or formaldehyde polymer in an amount that inhibits the molecular weight reduction reaction. That is, after the polycondensation step, it is preferable to perform the following purification steps on the modified phenol resin in any order or, if necessary, simultaneously in order to control the reaction to reduce the molecular weight of the phenols.

(I) A purification step of treating / precipitating with a specific solvent to remove solvent-soluble components including unreacted components, and (i
i) A purification step of dissolving in a specific solvent to remove the catalyst residue and the cross-linking agent can be mentioned. That is, in the refining step (i) for removing such unreacted components, the reactivity contained in the raw material petroleum heavy oils or pitches is low, and the unreacted or insufficiently reacted. No ingredients,
And a step of removing the solvent used in the reaction.

Specifically, the reaction product obtained in the polycondensation step is treated with an aliphatic hydrocarbon having 10 or less carbon atoms or an alicyclic ring having 10 or less carbon atoms at any time after the completion of the heating reaction. At least one selected from the group consisting of formula hydrocarbons
Pour into a specific solvent containing various compounds to precipitate the resin main component, and remove components soluble in the solvent, that is, components that remain unreacted and low reaction and reaction solvent during polycondensation reaction. Done by. Specific examples of such a hydrocarbon solvent include aliphatic or alicyclic hydrocarbons such as pentane, hexane, heptane, and cyclohexane, and n-hexane is particularly preferable.

In the purification step (ii) for removing the catalyst residue such as acid and the cross-linking agent, in order to remove the catalyst residue such as acid and the cross-linking agent remaining in the reaction mixture obtained by the polycondensation step, an acid catalyst is used. The solubility of the cross-linking agent is 0.1 or less, preferably 0.07 or less, and it is hardly soluble. However, it is performed by performing an extraction treatment using an extraction solvent that dissolves most of the modified phenolic resin. The extraction solvent has a solubility of an acid catalyst of 0.1 or less and is hardly soluble, but is not particularly limited as long as it is a solvent capable of dissolving most of the modified phenolic resin. For example, aromatic hydrocarbons such as benzene, toluene and xylene. The class is preferable, and toluene is more preferable.

In the present invention, the refining step (ii) is not limited to the conditions such as its temperature, but may be carried out under the conditions that the above-mentioned characteristics of the solvent are sufficiently exhibited. In the purification step (ii), the reaction product may be added to the solvent, or conversely, the solvent may be added to the reaction product. Of course, the catalyst residue such as acid and the cross-linking agent can be substantially removed only by the above extraction treatment. However, if desired, the modified phenolic resin after the purification step (ii) by the extraction treatment is usually followed by the following steps. Neutralization treatment and /
Alternatively, washing with water may be performed to further remove catalyst residues such as acids in the resin.

Particularly, after the extraction treatment, the neutralization treatment is preferably performed when a slight amount of acid catalyst or the like may remain in the extraction solution. Examples of the neutralization treatment include addition of a basic substance to the modified phenol resin after the purification step (ii). Examples of the basic substance include hydroxides of alkali metals such as sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide, alkaline earth metal hydroxides; ammonia, diethylenetriamine, triethylenetetramine, aniline, phenylenediamine, etc. Can be mentioned.

In the purification step of the present invention, such purification steps (i) and (ii) can be performed in any order. However, the modified phenolic resin after the purification step (ii) is usually in the form of a varnish dissolved in a solvent, and this varnished modified phenolic resin is used as it is or after adjusting the resin concentration by concentrating or adding an organic solvent. It can be used as a raw material in the step of lowering the molecular weight. In addition, the varnish-like modified phenol resin is collected as a powdery modified phenol resin which is put into a solvent in which the modified phenol resin is insoluble, for example, n-hexane and is re-precipitated, and is a raw material for the subsequent low molecular weight conversion step. You may use as.

(2) Production of highly reactive modified phenolic resin:
The novel highly reactive modified phenolic resin of the present invention is obtained by the method described in Japanese Patent Application No. 6-23617, for example, such a modified phenolic resin, that is, the reaction product obtained in the polycondensation step as it is or purified. Later, it can be produced by reacting with phenols in the absence of a formaldehyde polymer and other cross-linking agent and in the presence of an acid catalyst to lower the molecular weight.

In such a low molecular weight reaction, the modified phenolic resin is cut and dissociated by breaking and dissociating the acetal bond and / or methylene ether bond present in the molecule, and the phenols are added to the dissociated terminal portion. It is considered that since these compounds bind to each other to increase the phenol content of the modified phenolic resin, a highly reactive modified phenolic resin having a low resin melt viscosity and excellent reactivity with an epoxy resin can be obtained.

Therefore, the amount of the raw material and the acid catalyst used in the step of lowering the molecular weight, the type and combination thereof, the reaction conditions such as the reaction temperature, etc., are the lower molecular weight of the modified phenol resin and the reaction activity with the epoxy resin. There is no particular limitation as long as it is a range that can improve the above. However, it is important to appropriately select the reaction conditions such as the type and amount of the acid catalyst used in the molecular weight reduction step, the reaction temperature, and / or the type and amount of the reaction solvent. The phenols and acid catalysts used in the molecular weight reduction step may include the compounds exemplified in the polycondensation step.

In the step of lowering the molecular weight of the present invention, the phenols react sufficiently if they are 10% by weight or more based on the weight of the modified phenol resin, but if too much phenol is used, a large amount of unreacted phenols is used. Remains, resulting in an increase in the cost required for the post-treatment, so the content is preferably 10 to 300% by weight. Further, the addition of phenols does not necessarily have to be sequential addition, and the entire amount may be introduced into the reaction system at the start of the reaction.

The amount of the acid catalyst used is 0.1% by weight or more, preferably 0.1 to 1% by weight based on the weight of the modified phenolic resin.
It is desirable to use 5% by weight, more preferably 0.1 to 10% by weight, and even more preferably 0.2 to 10% by weight. In the step of lowering the molecular weight, the reaction solvent may or may not be used. The reaction solvent used is not particularly limited as long as it does not inhibit the above-mentioned molecular weight reduction reaction,
Examples thereof include solvents used in the polycondensation reaction, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone: alcohols such as methyl alcohol, ethyl alcohol and n-butyl alcohol: ethers such as tetrahydrofuran.

Such a solvent is preferably used in an amount of 0 to 300% by weight based on the modified phenolic resin. The reaction temperature is not particularly limited, but is usually 50 to 120 ° C, preferably 80 to 120 ° C. The reaction time is not particularly limited, and is, for example, 15 minutes to 3.0 hours, preferably 30 minutes to 2.0 hours.

(3) Post-treatment of highly reactive modified phenolic resin Since the highly reactive modified phenolic resin may leave unreacted components, catalyst residues such as acids, etc., it is purified by a method such as washing with water. However, it is necessary to remove unreacted components and catalyst residues such as acids. Preferably, the reaction product is diluted using a mixed solvent of toluene and alcohols such as methanol and ethanol or a mixed solvent of toluene and ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and then distilled water and / or Alternatively, washing treatment is performed with a mixed liquid of distilled water and isopropyl alcohol to remove unreacted components such as phenols and catalyst residues such as acids.

Further, the highly reactive modified phenolic resin is
After removing unreacted components and catalyst residues such as acids as described above, the extraction solvent is desolvated, or a solvent in which the highly reactive modified phenolic resin is insoluble, that is, an aliphatic or alicyclic group having 10 or less carbon atoms. The resin is preferably precipitated by treatment with a formula hydrocarbon or a mixed solvent thereof. Examples of such a hydrocarbon solvent include the solvents described in the step of purifying the modified phenolic resin, and n-hexane is particularly preferable.

Features of highly reactive modified phenolic resin (A) (a) The highly reactive modified phenolic resin (A) itself has the following features as compared with the modified phenolic resin. -The number average molecular weight decreases, and the number average molecular weight is 300-
It has a molecular weight of 800, the reactivity with the epoxy resin (B) is improved, and the resin melt viscosity is reduced.

Therefore, the highly reactive modified phenolic resin (A) is excellent in moldability because of its low resin melt viscosity, and has high reactivity with the epoxy resin (B), and is therefore particularly combined with the epoxy resin (B). And, it is possible to provide a binder for a friction material having excellent mechanical properties such as strength. Also,
Since the highly reactive modified phenolic resin (A) does not substantially contain an acid, it has no corrosiveness with respect to a metal part of an automobile or the like with which the friction material comes in contact, and the reactivity with the epoxy resin (B) is improved. Therefore, heat resistance and dimensional stability are improved, and a binder which is convenient as a friction material can be provided.

(B) Blending of Epoxy Resin (B) When the highly reactive modified phenolic resin (A) of the present invention is used as a binder for friction materials, it is necessary to blend the epoxy resin (B). . The friction material thus obtained has a small molding shrinkage, and can further have improved heat resistance, wear resistance and the like. In this case, it is a more preferable aspect to incorporate a curing agent and / or a curing accelerator (D).

Examples of the epoxy resin include glycidyl ether type, glycidyl ester type, glycidyl amine type, mixed type, biphenyl type and alicyclic type epoxy resins. More specifically, as the glycidyl ether type (phenolic type), bisphenol A type epoxy resin, bisphenol F type epoxy resin,
Tetrabromobisphenol A type epoxy resin, tetraphenylolethane type epoxy resin, phenol novolac type epoxy resin, o-cresol novolac type epoxy resin and the like;

The glycidyl ether type (alcohol type) includes polypropylene glycol type epoxy resin, water-added bisphenol A type epoxy resin and the like; the glycidyl ester type includes hexahydrophthalic anhydride type epoxy resin, dimer acid type epoxy resin and the like. Glycidylamine type includes diaminodiphenylmethane type epoxy resin, isocyanuric acid type epoxy resin, hydantoic acid type epoxy resin and the like; mixed type includes p-aminophenol type epoxy resin, p-oxybenzoic acid type epoxy resin and the like. Can be mentioned. Of the above epoxy resins,
Bisphenol A type epoxy resin, glycidyl amine type epoxy resin, phenol novolac type epoxy resin,
Biphenyl type epoxy resin is preferred. A combination of two or more of the above epoxy resins can also be used.

The mixing ratio of the highly reactive modified phenolic resin (A) and the epoxy resin (B) is not particularly limited, but the total amount of the highly reactive modified phenolic resin (A) and the epoxy resin (B) is 100 parts by weight. October 90-90 / 10
(Parts by weight) is preferable, and more preferably 20
/ 80 to 80/20 (parts by weight). Here, if the weight ratio of the highly reactive modified phenolic resin (A) is less than 10 parts by weight, the effect of improving the heat resistance and moisture resistance of the obtained friction material is not sufficient, and if it exceeds 90 parts by weight, the molding temperature is It tends to increase.

(C) Blending of a curing agent and a curing accelerator (D) The highly reactive modified phenolic resin (A) used as a binder for a friction material, together with the epoxy resin (B), a curing agent and / or a curing accelerator (D). ) Is desirable. Various things can be used as a hardening agent and / or a hardening accelerator (D).

As the curing agent, for example, cyclic amines,
Examples thereof include aliphatic amines, polyamides, aromatic polyamines and acid anhydrides. Specifically, for example, as cyclic amines, hexamethylenetetramine and the like; as aliphatic amines, diethylenetriamine,
Triethylenetetramine, tetraethylenepentamine,
Diethylaminopropylamine, N-aminoethylpiperazine, isophoronediamine, bis (4-amino-3-)
Methylcyclohexyl) methane, menthanediamine, etc .;
Polyamides include vegetable oil fatty acids (dimer or trimer acid), aliphatic polyamine condensates, etc .;

The aromatic polyamines include m-phenylenediamine, 4,4'-diaminodiphenylmethane,
4,4′-diaminodiphenyl sulfone, m-xylylenediamine, etc .; as the acid anhydrides, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride,
Trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, chlorendic anhydride, dodecynyl succinic anhydride, methyltetrahydrophthalic anhydride,
Methyl endomethylene tetrahydrophthalic anhydride etc. can be mentioned.

The curing accelerator is not particularly limited as long as it accelerates the curing reaction. For example, diazabicycloalkene such as 1,8-diazabicyclo (5,4,0) undecene-7 and its derivatives; triethylenediamine. , Benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl)
Tertiary amines such as phenol; 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole and other imidazoles;

Organic phosphines such as tributylphosphine, methyldiphenylphosphine and triphenylphosphine; tetra-substituted phosphonium / tetra-substituted borates such as tetraphenylphosphonium / tetraphenylborate; 2-ethyl-4-methylimidazole / tetraphenylborate , A tetraphenylboron salt such as N-methylmorpholine / tetraphenylborate, a Lewis acid such as boron trifluoride-amine complex and a Lewis base such as tris (dimethylaminomethyl) phenol, benzyldimethylamine, dicyandiamide, and adipic dihydrazide, Other examples include polymercaptan and polysulfide. Further, these curing agents and curing accelerators may be used alone or in combination of two or more.

(D) Other Additives In the composition containing the binder for friction materials of the present invention, various additives such as flame retardants, light stabilizers, antioxidants, pigments, and A filler or the like can be added.

(2) Friction base material (C) The friction base material (C), which is another component of the friction material of the present invention, mainly contains a reinforcing fiber and a friction modifier. (A) Reinforcing fiber As the reinforcing fiber, the material of the reinforcing fiber is at least one selected from glass fiber, inorganic fiber such as asbestos fiber, organic fiber such as staple fiber or carbon fiber, and the reinforcing fiber is short fiber, Milled fiber, filament (filament)
It is desirable that the shape of the reinforcing fiber is at least one selected from the group consisting of fiber alone, non-woven fabric, and woven fabric.

(B) Well-known fillers can be widely used as friction modifiers, for example, metal oxides such as aluminum oxide, iron oxide and copper oxide; hydrated metal oxides such as aluminum hydroxide and magnesium hydroxide. Materials; metal carbonates such as magnesium carbonate and calcium carbonate; metal borates such as barium sulfate and magnesium borate; inorganic fillers such as silica, mica and fused silica; metal powders such as copper powder, iron powder, aluminum powder; cashew Examples thereof include dust and graphite. The mixing ratio of the reinforcing fiber and the friction modifier is 55:
45-75: 25, preferably 60: 40-70: 30
It is.

(3) Manufacture of friction material As a method of manufacturing a friction material, (i) a highly reactive modified phenolic resin (A) with an epoxy resin (B) and a curing agent and / or a curing accelerator (D), Further, a method in which various additives are added and mixed as required and mixed with the friction base material (C) and hot-pressed, (ii) highly reactive modified phenolic resin (A), epoxy resin (B) and If necessary, a friction base material (C) is impregnated with a solvent solution containing a curing agent and / or a curing accelerator (D) and further various additives, dried, shaped, and thermocompressed. A method of firing may be used accordingly.

In the method (i) for producing the friction material, the highly reactive modified phenolic resin (A) is the molded powdery product obtained by post-treating the highly reactive modified phenolic resin in which the purified modified phenolic resin has a low molecular weight. You can use it. Therefore, the epoxy resin (B) and the curing agent and / or the curing accelerator (D)
The above-mentioned highly reactive modified phenolic resin (A) may be added and mixed at a predetermined ratio and crushed, or crushed or mixed after crushing.

In the method (ii) for producing the friction material, the solvent solution is used as a good solvent for both the highly reactive modified phenolic resin (A) and the epoxy resin (B), and the highly reactive modified phenolic resin (A) and the epoxy resin ( B), the curing agent and / or the curing accelerator (D) may be prepared simultaneously or sequentially by dissolving,
Alternatively, after preparing a solvent solution of a good solvent of the highly reactive modified phenolic resin (A) and a solvent solution of a good solvent of the epoxy resin (B), both may be mixed. The mixing timing of the curing agent and / or the curing accelerator (D) and the like may be appropriately selected.

The solvent solution of the highly reactive modified phenolic resin (A) is prepared by dissolving the purified modified phenolic resin into a low-molecular-weight highly reactive modified phenolic resin, and dissolving it in a suitable solvent. Alternatively, it may be diluted and adjusted to a viscosity suitable for impregnation. The solvent for dissolving and / or diluting the highly reactive modified phenolic resin (A) is not particularly limited as long as it can dissolve the resin component constituting the binder to be used as a soluble component as much as possible, and even a single solvent may be used. It may be a mixed solvent.

Examples of good solvents for the highly reactive modified phenolic resin (A) include aromatic hydrocarbons such as benzene, toluene and xylene; amides such as dimethylacetamide; halogenated aromatic hydrocarbons such as chlorobenzene; Ethers such as tetrahydrofuran and dioxane; alcohols such as methanol and ethanol; glycols such as ethyl cellosolve; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone;
Esters such as ethyl acetate; chloroform, methylene chloride, perclen or a mixture thereof can be mentioned. Among them, it is preferable to use at least one organic solvent selected from aromatic hydrocarbons, amides, ketones, alcohols and halogenated aromatic hydrocarbons.

On the other hand, the good solvent for the epoxy resin (B) is appropriately selected and used from organic solvents which have been widely used in the past. For example, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; methanol, Preference is given to alcohols such as ethanol; aromatic hydrocarbons such as toluene and xylene, or a mixture thereof. Further, in the manufacturing methods (i) to (ii) of the friction material, the thermocompression molding condition is a temperature at which the highly reactive modified phenolic resin or the like constituting the binder is crosslinked, for example, 150 to 300.
℃, preferably 150-250 ℃, pressure 10-230
kg / cm ^2, preferably from 10 to 200 / cm ² or less, molding time of 10 minutes to 10 hours. Since these conditions are functions of temperature, pressure and time, specifically, appropriate numerical values within the above range should be selected.

In the production of the friction material of the present invention, after thermocompression molding, if necessary, 130 to 250 ° C., preferably 150.
It is recommended to carry out post-baking at ~ 200 ° C for 10 minutes to 10 hours. The use ratio of the binder and the friction base material is usually 7: 100 to 30 :.
The range is 100, preferably 7: 100 to 25: 100.

[0058]

The present invention will be described in more detail and specifically below by way of Examples, which do not limit the scope of the present invention. In the following, all parts are by weight unless otherwise specified. Table 1 shows the properties of the feedstock oil used as the reaction feedstock. These feedstocks are obtained by distilling the bottom oil obtained by fluid catalytic cracking (FCC) of vacuum gas oil.

[0059]

[Table 1]

<Synthesis of highly reactive modified phenolic resin> (Production Example 1) 334 g of feed oil, 3 paraformaldehyde
70 g, p-toluenesulfonic acid monohydrate 137 g and p-xylene 678.5 g were charged into a glass reactor,
The temperature was raised to 95 ° C. while stirring. After holding at 95 ° C. for 1 hour, 209 g of phenol was dropped at a dropping rate of 1.3 g / min, and after completion of the dropping of phenol, the mixture was stirred and reacted for 15 minutes. Next, the reaction mixture was poured into 3,300 g of n-hexane to precipitate a reaction product, which was filtered to remove unreacted components and reaction solvent. The precipitate was washed with 1,600 g of n-hexane and then vacuum dried to obtain an acid-containing crude modified phenol resin.

This resin was dissolved in 10 times the weight of toluene (the solubility of p-toluenesulfonic acid monohydrate in toluene is 0.01 or less), and insoluble with p-toluenesulfonic acid monohydrate as the main component. The fraction (including unreacted paraformaldehyde) was filtered. The obtained resin toluene solution was concentrated to a resin concentration of 50% to obtain a varnish-like modified phenol resin. Furthermore, a trace amount of triethylenetetramine was added to neutralize. This modified phenolic resin varnish was poured into 3.3 times by weight of n-hexane to precipitate a resin, which was then filtered. Then, it was vacuum dried to obtain 580 g of powdered modified phenolic resin. 100 g of the obtained modified phenolic resin, 200 g of phenol, and 5 g of p-toluenesulfonic acid were charged into a 500 ml glass reactor,
The temperature was raised to 95 ° C. with stirring at a speed of 250 to 350 rpm, and the reaction was carried out at 95 ° C. for 90 minutes to obtain a reaction product.

The above reaction product was mixed with toluene / methylisobutylketone mixed solution in an amount twice that of the product (mixing ratio 4/1).
To prepare a resin solution. The resin solution obtained was washed with distilled water / isopropanol mixed solution to extract and remove the acid and unreacted components contained in the reaction product, and then the toluene / methyl isobutyl ketone mixed solution was removed with an evaporator, Further, it was vacuum dried under heating to obtain 190 g of a highly reactive modified phenol resin powder containing substantially no acid. Methyl ethyl ketone was added to this resin powder so that the resin concentration was 30% by weight, and further concentrated to 60% by weight to obtain 317 g of a highly reactive modified phenol resin solution.

<Production of Friction Material from Highly Reactive Modified Phenolic Resin> (Example 1) 40 parts by weight of highly reactive modified phenolic resin powder obtained in Production Example 1 and bisphenol A type epoxy resin [oiled shell epoxy Co., Ltd., trade name Epikote 828] 60 parts by weight are mixed and stirred at room temperature using an automatic mortar, and then 2-ethyl-4-methylimidazole [Wako Pharmaceutical Co., Ltd., first grade] 2 as a curing accelerator. 0.04 part by weight was added and mixed to obtain a curable resin-containing binder powder.

18 parts by weight of the curable resin-containing binder was mixed with 65 parts by weight of short fibrous carbon fiber, 7 parts of barium sulfate, 8 parts of cashew dust and 2 parts of copper powder, and the mixture was put into a predetermined mold. , 170 ° C., 200 kg / cm ^{2 for} 10 minutes. The obtained friction material had a bending strength of 15 kg / mm ² measured by a method according to JIS K6911,
The Charby impact strength measured by the method according to JIS K6911 was 5.0 kg · cm / cm ² . Further, as shown in Table 2, the heat resistance is good, the friction coefficient,
The amount of wear is also greater than the reference value, and it is the same as that of the conventional Japanese Patent Laid-Open No. 53-108.
It was found that the friction material had excellent heat resistance, friction coefficient, and wear amount as compared with the friction material described in Japanese Patent Publication No. 197.

Example 2 The same operation as in Example 1 was carried out to obtain a modified phenol resin powder containing substantially no acid.
500 g of 100 g of the obtained resin powder, 66 g of phenol, 40 g of toluene and 1.5 g of p-toluenesulfonic acid are added.
Charge into a ml glass reaction vessel, 250-300 rpm
The temperature was raised to 95 ° C with stirring at the speed of
The reaction was carried out by holding for a minute to obtain a reaction product containing a highly reactive modified phenolic resin. The reaction product is
Double volume of toluene / methyl alcohol mixture (mixing ratio 4 /
It melt | dissolved in 1) and prepared the resin solution.

The obtained resin solution is washed with distilled water / isopropanol mixed solution to extract and remove the acid and unreacted components contained in the reaction product, and then the toluene / methyl alcohol mixed solution is removed with an evaporator. Then, it was vacuum dried under heating to obtain a modified phenol resin powder which was substantially acid-free at 140 ° C. This resin powder has a resin concentration of 6
Methyl ethyl ketone was added to 0% by weight to obtain 233 g of highly reactive modified phenolic resin.

Carbon fiber containing 10% cashew dust and brass wire was dipped in the binder solution and dried in a dryer at 125 ° C. for 8 minutes to obtain a carbon fiber having a resin impregnation amount of 24.0%. This is shaped into a non-woven fabric, 160 ℃, 180kg
/ Cm ² for 7 minutes, followed by post-baking at 180 ° C. for 4 hours. The obtained friction material has a bending strength of 17 kg / mm.
² , the Charby impact strength was 5.0 kg · cm / cm ² . Also, as shown in Table 2, the heat resistance is good,
The coefficient of friction and the amount of wear are also above the reference values, and the conventional Japanese Patent Laid-Open No.
It was found that the friction material had excellent heat resistance, friction coefficient, and wear amount as compared with the friction material described in JP-A-3-108197.

[0068]

[Table 2]

[0069]

INDUSTRIAL APPLICABILITY The friction material of the present invention is excellent in high-temperature stability (heat resistance) by using a novel highly reactive modified phenolic resin as a binder and, in combination with the use of a friction base material, has a high temperature. It has the characteristics that the friction coefficient against temperature and speed is stable, and that it has excellent wear resistance at high temperature, bending strength, and impact strength.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 25, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

(B) Formaldehyde polymer As the formaldehyde polymer as a raw material, there can be mentioned linear polymer such as paraformaldehyde, polyoxymethylene (particularly, oligomer) and cyclic polymer such as trioxane. The mixing ratio of heavy petroleum oils or pitches (a) and formaldehyde polymer (b) is
The number of moles of the formaldehyde polymer in terms of formaldehyde is 1 to 15, preferably 2 to 12, and more preferably 3 to 11 per 1 mole of the average number of moles calculated from the average molecular weight of heavy petroleum oils or pitches. I need to be there. If this mixing ratio is less than 1, a friction material having sufficient strength may not be obtained, which is not preferable. On the other hand, when the mixing ratio is more than 15, the performance of the obtained friction material and the yield of the modified phenol resin are almost unchanged, so it is considered useless to use more formaldehyde polymer. Further, the excess formaldehyde polymer may hinder the molecular weight reduction of the modified phenol resin in the molecular weight reduction step described later.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

If the amount added is less than 0.3, the reactivity of heavy petroleum oils or pitches with formaldehyde will be inferior to that of phenols with formaldehyde, so a sufficient crosslinking density will be obtained. Therefore, a friction material having sufficient strength cannot be obtained. In particular, it has a low impact resistance and tends to be brittle. On the other hand, the amount of phenols added is 5
If it exceeds, the modification effect due to the modification of the phenol resin tends to be small.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Change

[Correction contents]

(3) Manufacture of Friction Material As a method for manufacturing the friction material, (i) a highly reactive modified phenolic resin (A), an epoxy resin (B), a curing agent and / or a curing accelerator (D), Furthermore, a method in which various additives are added and mixed as required, and mixed with the friction base material (C) and subjected to thermocompression molding, (ii) highly reactive modified phenolic resin (A), epoxy resin (B) and curing agent and / or curing accelerator if necessary (D), it is further impregnated with various additives including soluble liquid friction base material (C), dried, and shaped, after hot press forming, need And the like.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction item name] 0053

[Correction method] Change

[Correction contents]

[0053] The friction material manufacturing method in (ii), soluble
The liquid is a good solvent for both the highly reactive modified phenolic resin (A) and the epoxy resin (B), the highly reactive modified phenolic resin (A), the epoxy resin (B), the curing agent and / or the curing accelerator (D). May be prepared by simultaneously or sequentially dissolving,
Or a good solvent for highly reactive modified phenolic resin (A)
After preparing the solution of 1 ) and the good solvent solution of the epoxy resin (B), both may be mixed. The mixing timing of the curing agent and / or the curing accelerator (D) and the like may be appropriately selected.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0054

[Correction method] Change

[Correction contents]

The highly reactive modified phenolic resin (A) solution is a highly reactive modified phenolic resin obtained by post-treating a highly reactive modified phenolic resin having a low molecular weight refined modified phenolic resin dissolved in a suitable solvent. And / or may be diluted to adjust the viscosity suitable for impregnation. The solvent for dissolving and / or diluting the highly reactive modified phenolic resin (A) is not particularly limited as long as it can dissolve the resin component constituting the binder to be used as a soluble component as much as possible, and even a single solvent may be used. It may be a mixed solvent.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0062

[Correction method] Change

[Correction contents]

The above reaction product was mixed with a toluene / methyl isoptyl ketone mixed solution in an amount twice that of the product (mixing ratio: 4/1).
To prepare a resin solution. The obtained resin solution was washed with distilled water / isopropanol mixed solution to extract and remove the acid and unreacted components contained in the reaction product, and then the toluene / methyl isobutyl ketone mixed solution was removed with an evaporator. Further, it was vacuum dried under heating to obtain 190 g of a highly reactive modified phenol resin powder containing substantially no acid. Methyl ethyl ketone was added to this resin powder so that the resin concentration was 60 % by weight to obtain 317 g of a highly reactive modified phenol resin solution.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0063

[Correction method] Change

[Correction contents]

<Production of Friction Material from Highly Reactive Modified Phenolic Resin> (Example 1) 40 parts by weight of highly reactive modified phenolic resin powder obtained in Production Example 1 and bisphenol A type epoxy resin [oiled shell epoxy Ltd., after the trade name Epikote 828] 60 parts by weight and stirred mixed-2-ethyl-4-methylimidazole as a curing accelerator [Wako pharmaceutical Co. Ltd., first grade] added 2.04 parts by weight Upon mixing, a curable resin-containing binder was obtained.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0064

[Correction method] Change

[Correction contents]

18 parts by weight of the curable resin-containing binder was mixed with 65 parts by weight of short fibrous carbon fiber, 7 parts of barium sulfate, 8 parts of cashew dust and 2 parts of copper powder, and the mixture was put into a predetermined mold. , 170 ° C., 200 kg / cm ^{2 for} 10 minutes. The obtained friction material had a bending strength of 15 kg / mm ² measured by a method according to JIS K6911 method,
The Charby impact strength measured by the method according to JIS K6911 was 5.0 kg · cm / cm ² . Further, as shown in Table 2, the heat resistance is good, the friction coefficient,
The amount of wear was good .

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0066

[Correction method] Change

[Correction contents]

The obtained resin solution is washed with distilled water / isopropanol mixed solution to extract and remove the acid and unreacted components contained in the reaction product, and then the toluene / methyl alcohol mixed solution is removed with an evaporator. Then, it was vacuum dried under heating to obtain a modified phenol resin powder which was substantially acid-free at 140 ° C. This resin powder has a resin concentration of 6
Methyl ethyl ketone was added to 0% by weight to obtain 233 g of a highly reactive modified phenol resin solution .

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0067

[Correction method] Change

[Correction contents]

A shore surface fiber containing 10% cashew dust and brass wire was dipped in the binder solution and dried in a dryer at 125 ° C. for 8 minutes to obtain a carbon fiber having a resin impregnation amount of 24.0%. This is shaped into a non-woven fabric, 160 ℃, 180kg
/ Cm ² for 7 minutes, and post-baking was performed at 180 ° C. for 4 hours. The obtained friction material has a bending strength of 17 kg / mm.
² , the Charby impact strength was 5.0 kg · cm / cm ² . Further, as shown in Table 2, the heat resistance was excellent , and the friction coefficient and the wear amount were good .

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

[0068]

[Table 2]

Claims (5)

[Claims] 1. A modified phenolic resin obtained by polycondensing (A) a petroleum heavy oil or pitches, a formaldehyde polymer and a phenol in the presence of an acid catalyst in the presence of an acid catalyst. A highly reactive modified phenolic resin-based friction material comprising a binder composed of a highly reactive modified phenolic resin having a low molecular weight with phenols and (B) an epoxy resin, and (C) a friction base material. 2. The highly reactive modified phenolic resin-based friction material according to claim 1, wherein the binder further contains a curing agent and / or a curing accelerator (D). 3. The highly reactive modified phenolic resin-based friction material according to claim 1, wherein the friction base material (C) is a reinforcing fiber and a friction modifier. 4. A highly reactive modified phenolic resin (A), an epoxy resin (B), a curing agent and / or a curing accelerator (D) are mixed with a friction base material (C), and the temperature is 150 to 300.
A method for producing a highly reactive modified phenolic resin-based friction material, which comprises hot-pressing at a temperature of 10 to 230 kg / cm ² and post-baking at 130 to 250 ° C. if necessary. 5. A solution containing a highly reactive modified phenolic resin (A) and an epoxy resin (B) and a curing agent and / or a curing accelerator (D) is prepared and the friction base material (C) is impregnated with the solution. After being dried, shaped, shaped, thermocompressed at a temperature of 150 to 300 ° C. and a pressure of 10 to 230 kg / cm ² , and then post-baked at 130 to 250 ° C., if necessary, highly reactive modification. Manufacturing method of phenol resin type friction material.