JP2001049079A - Phenolic resin composition and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve tenacity, vibration absorbing properties, flexibility and heat resistance by compounding a silicone gel based on an addition reaction type silicone having a specific penetration and an aromatic hydrocarbon-modified phenolic resin. SOLUTION: A vinyl group-containing dimethylpolysiloxane and a polymethylhydrogensiloxane are heated in the presence of a catalyst thereby effecting a hydrosilylation reaction to give a silicone gel (A) based on an addition reaction type silicone having a penetration of 10-300 (JIS K 2530-1976, under a load of 50 g). The component A in an amount of 1-50 pts.wt. and 100 pts.wt. of an aromatic hydrocarbon-modified phenolic resin (B) obtained by polycondensation of a phenolic compound with an aromatic hydrocarbon are fed to a pressure kneader and kneaded at 50-150 deg.C to give a phenolic resin composition. This phenolic resin composition can include 3-20 pts.wt., based on 100 pts.wt. of the component B, of a curing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phenolic resin composition having excellent toughness, vibration absorption and flexibility, and having good heat resistance. The present invention relates to a phenol resin composition suitable as a binder used for obtaining a friction material having excellent vibration absorption, abrasion resistance and fade resistance.

[0002]

2. Description of the Related Art Phenol resins are binders having excellent mechanical properties, electrical properties, heat resistance and adhesiveness, but molded articles have drawbacks in toughness and vibration absorption. In order to improve such performances, research on modified phenolic resins has been actively conducted, and oil-modified phenolic resins, cashew-modified phenolic resins, epoxy-modified phenolic resins, melamine-modified phenolic resins, etc. have been studied, and some of them have been put into practical use. Has been provided. However, these modified phenolic resins are not yet sufficient in terms of toughness and vibration absorption.

[0003] In order to further improve the flexibility and vibration absorption, various rubber-modified phenol resins having relatively excellent properties have been studied. There was a problem that squealing occurred due to history. Therefore, as disclosed in JP-A-8-86326, there is an example in which a silicone gel having excellent heat resistance is used to improve flexibility, vibration absorption, and heat resistance. However, in this example, there is a problem that the heat resistance of the phenol resin serving as the matrix resin is not sufficient, and the strength deteriorates due to the heat history in a more severe use environment.

[0004]

SUMMARY OF THE INVENTION The present invention has been completed as a result of various studies to solve such problems of the phenolic resin, and its object is to improve toughness, vibration absorption and flexibility. An object of the present invention is to provide a phenol resin composition which is excellent and has good heat resistance.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a specific silicone gel and an aromatic hydrocarbon-modified phenolic resin obtained by polycondensing phenols, aromatic hydrocarbons and aldehydes (hereinafter simply referred to as aromatic resins). Group (which is referred to as a phenol resin modified with an aromatic hydrocarbon) greatly affects these properties, and the present invention has been completed. That is, the present invention relates to a penetration (JIS K 2530-1976-50).
g load) (hereinafter simply referred to as penetration), a phenolic resin composition comprising an addition-reaction-type silicone-based silicone gel having an average of 10 to 300, and an aromatic hydrocarbon-modified phenolic resin as essential components. It is about things.

Hereinafter, the present invention will be described specifically.
The silicone gel is generally obtained by adding a catalyst to vinyl group-containing dimethylpolysiloxane and polymethylhydrogensiloxane, heating and subjecting to a hydrosilylation reaction. Such a silicone gel having a penetration of 10 to 300 has appropriate flexibility, excellent impact resistance and vibration absorption, and does not lose these properties in a wide temperature range from room temperature to high temperature. More preferably, the penetration of the silicone gel is 100 to 200. If the penetration is less than 10, the flexibility is low, the impact resistance and the vibration absorption are not sufficient, and if it is more than 300, it is too soft and the strength is not sufficient. The composition of the present invention can be obtained by uniformly dispersing and mixing such a silicone gel in an aromatic hydrocarbon-modified phenol resin.

The phenolic resin composition thus obtained exhibits the heat resistance of the aromatic hydrocarbon-modified phenolic resin, the excellent flexibility and vibration absorption of the silicone gel, and a synergistic effect of these. This makes it possible to maintain high strength and flexibility after heat history. A method of uniformly dispersing and mixing a silicone gel in an aromatic hydrocarbon-modified phenol resin is to uniformly disperse and mix the silicone gel in the polycondensate in which the reaction has been completed in advance. And kneading under pressure by a pressure kneader. However, the silicone gel has poor compatibility with the polycondensate, is insoluble in a solvent, and has a high melting point.
It is desirable to use a pressure-type kneader because it is difficult to uniformly disperse it in a normal phenol resin reactor. That is, a predetermined amount of the polycondensate and the silicone gel are charged into a pressure-type kneader and kneaded under pressure. The temperature at the time of kneading is not particularly limited as long as it is a temperature at which the aromatic hydrocarbon-modified phenol resin is melted, but is usually 50 to 150 ° C., particularly 70 to 130 ° C. from the ease of kneading.
Is appropriate. As the pressure-type kneader, a roll-type kneader, a pressure kneader, a twin-screw extruder, a single-screw extruder and the like are suitable. By using a pressurized kneader, it becomes possible to uniformly disperse the silicone gel in the aromatic hydrocarbon-modified phenolic resin.

[0008] Phenols used for producing aromatic hydrocarbon-modified phenolic resins include phenol, cresol, xylenol, ethylphenol, propylphenol, catechol, resorcinol, hydroquinone,
Bisphenol A and the like may be used alone or in combination of two or more. As the aromatic hydrocarbon, benzene, toluene, xylene, mesitylene, etc.
Alternatively, a resin obtained by previously reacting these aromatic hydrocarbons with aldehydes can be used. Also,
It is also possible to use aromatic hydrocarbon glycols such as para-xylene glycol dimethyl ether, para-xylene glycol, meta-xylene glycol dimethyl ether, meta-xylene glycol, ortho-xylene glycol dimethyl ether, and ortho-xylene glycol, or alkyl ethers thereof.

Further, as the aldehydes, it is possible to use formaldehyde or a compound capable of forming formaldehyde, or an aldehyde such as benzaldehyde. As a catalyst for reacting a phenol with an aromatic hydrocarbon resin, metal salts such as zinc acetate, oxalic acid, hydrochloric acid, sulfuric acid, diethyl sulfuric acid, acids such as paratoluenesulfonic acid alone or in combination of two or more kinds Can be used.

The aromatic hydrocarbon-modified phenolic resins of the present invention include those obtained by reacting phenols with polycondensates of aromatic hydrocarbons and aldehydes, those obtained by reacting only phenols and xylene glycols, and those obtained by reacting phenols with phenols. It is obtained by reacting aldehydes with aromatic hydrocarbon modification. Further, a mixture of a polycondensate of a phenol and an aldehyde and a polycondensate of an aromatic hydrocarbon-modified phenol / formaldehyde may be used.

The silicone gel content of the phenolic resin composition of the present invention is based on 100 parts by weight of a polycondensate of a phenol and an aromatic hydrocarbon or a polycondensate of a phenol, an aromatic hydrocarbon and an aldehyde. , Usually 1-5
0 parts by weight, preferably 3 to 20 parts by weight. 1
If the amount is less than 10 parts by weight, sufficient flexibility and vibration absorption of the resin cannot be obtained.
As the molding time of the molded article becomes longer, the binder force becomes smaller, which is not practical. In the range of 3 to 20 parts by weight, it has particularly excellent flexibility and vibration absorption, and can maintain high strength after heat history.

As the curing agent for the phenolic resin composition, various epoxy compounds having two or more functionalities, isocyanates, formaldehyde resins and hexamethylenetetramine can be used as necessary, but from the viewpoint of curability and heat resistance. Hexamethylenetetramine is preferred. Hexamethylenetetramine can be used in an amount of 3 to 20 parts by weight, preferably 7 to 17 parts by weight, per 100 parts by weight of the polycondensate of phenols, aromatic hydrocarbons and aldehydes. . If the amount is less than 3 parts by weight, the resin will be insufficiently cured.

The phenolic resin composition of the present invention can be used as a material for a molding material, an organic fiber binder, a rubber compounding agent,
Examples of the binder include a binder for abrasives, a binder for friction materials, a rubber compounding agent, a binder for inorganic fibers, a coating agent for electronic and electrical parts, a binder for sliding members, an epoxy resin raw material, and an epoxy resin curing agent.

[0014]

The present invention will be described below with reference to examples. However, the present invention is not limited by these examples. Further, “parts” described in Examples and Comparative Examples
And "%" all indicate "parts by weight" and "% by weight".

Example 1 A reactor equipped with a stirrer, a reflux condenser and a thermometer was charged with 1000 parts of phenol, 900 parts of xylene / formaldehyde resin, 10 parts of zinc acetate, and 2 parts of paratoluenesulfonic acid, and then gradually raised. After the temperature reached 100 ° C., a reflux reaction was performed for 240 minutes. Dehydration at normal pressure is performed until the internal temperature reaches 110 ° C, and then vacuum dehydration is performed. When the temperature in the system rises to 160 ° C, the contents are taken out of the reactor and solid phenol / xylene / formaldehyde is formed at normal temperature. 1,700 parts of a polycondensate (hereinafter referred to as a xylene-modified phenol resin) were obtained.

Next, the xylene-modified phenolic resin 10
00 parts were charged into a melt kneader, heated to 150 ° C. and melted. 50 parts of silicone gel (αGEL manufactured by Seagel Co., Ltd., penetration 160) was added, and it was confirmed that the silicone gel was uniformly dispersed. The mixture was further kneaded for 30 minutes, removed from the pressure kneader, and solidified at room temperature. Phenol resin composition 1
030 parts were obtained. Further, hexamethylenetetramine 11 was added to 1000 parts of the obtained solid phenol resin composition.
0 parts, pulverized, and powdered phenolic resin composition 10
97 parts were obtained.

Example 2 A similar reactor as in Example 1 was charged with 1000 parts of phenol, 600 parts of xylene / formaldehyde resin and 2 parts of p-toluenesulfonic acid, and the temperature was gradually increased to 10 parts.
After reaching 0 ° C., a reflux reaction was performed for 120 minutes. Subsequently, 10 parts of zinc acetate and 270 parts of 37% formaldehyde were charged and a reflux reaction was carried out for 120 minutes. Thereafter, the reaction was carried out in the same manner as in Example 1 and solid xylene-modified phenol resin 1 at room temperature
300 parts were obtained. Thereafter, a silicone gel was added, kneaded, and pulverized in the same manner as in Example 1 to obtain a powdered phenol resin composition 1.
097 parts were obtained.

Example 3 The charge amount of silicone gel (αGEL manufactured by C-Gel Co., Ltd., penetration 160) with respect to 1000 parts of a polycondensate with a xylene-modified phenol resin obtained in the same manner as in Example 1 Kneading was carried out in the same manner as in Example 1 except that the amount was changed to 100 parts, to obtain 1030 parts of a phenol resin composition which was solid at ordinary temperature. Thereafter, pulverization was carried out in the same manner as in Example 1 to obtain 1097 parts of a powdery phenol resin composition.

Comparative Example 1 Novolak type phenolic resin (manufactured by Sumitomo Durez Co., Ltd.)
R-53195) To 1000 parts of 110 parts of hexamethylenetetramine was added and pulverized to obtain 1099 parts of a powdery phenol resin composition.

Comparative Example 2 A pressure kneader was charged with 1000 parts of a novolak type phenol resin (PR-53195, manufactured by Sumitomo Durez Co., Ltd.).
The temperature was raised to 150 ° C. and melted. Silicone gel (Co., Ltd.)
50 parts of αGEL made by Siegel, penetration 160) was added, and it was confirmed that the silicone gel was uniformly dispersed. The mixture was further kneaded for 30 minutes, taken out from the pressure kneader, and 1030 parts of a phenol resin composition which was solid at room temperature. I got Further, 110 parts of hexamethylenetetramine was added to 1000 parts of the obtained solid phenol resin composition, and pulverized to obtain 1097 parts of a powdered phenol resin composition.

Comparative Example 3 1000 parts of phenol, 900 parts of xylene / formaldehyde resin, 10 parts of zinc acetate and 2 parts of paratoluenesulfonic acid were charged into a reactor equipped with a stirrer, a reflux condenser and a thermometer, and then gradually raised. After the temperature reached 100 ° C., a reflux reaction was performed for 240 minutes. Dehydration under normal pressure was performed until the internal temperature reached 110 ° C., and then vacuum dehydration was performed. When the temperature in the system was raised to 160 ° C., the contents were taken out of the reactor and solid xylene-modified phenol resin 1700 at normal temperature was obtained. Got a part. Further, hexamethylenetetramine 110 was added to 1000 parts of the xylene-modified phenol resin.
Parts, and pulverized to obtain a powdered phenol resin composition 109.
7 parts were obtained.

Obtained in Examples 1-3 and Comparative Examples 1-3
For the six types of powdered phenolic resin compositions,
The mixing was performed at the indicated mixing ratio. Compounding amount (% by weight) Phenolic resin composition 10 aramid fiber 5 calcium carbonate 45Barium sulfate 40

[0023] This composition is heated at a temperature of 160 ° C and a pressure of 200k.
g / cm ² for 10 minutes, 150 × 150 × 20m
m was obtained. The obtained molded product was fired at 180 ° C. for 8 hours, and the Rockwell hardness of the molded product and an electrokinetic vibration test device (IMV type, VS-2000A-10) were used.
The vibration acceleration according to 0) was measured. Further, the normal bending strength and the bending strength after heat history were measured. Table 1 shows the results.

Table 1 Example of evaluation results Comparative Example 1 2 3 1 2 3 Rockwell hardness (HRS) 76 74 69 84 76 83 Vibration acceleration (G) 28 27 23 46 28 45 Normal bending strength (MPa) 37 37 38 37 38 36 Flexural strength after heat history (MPa) After treatment at 350 ° C x 2 hours 28 25 29 16 20 27 After treatment at 350 ° C x 8 hours 22 17 21 8 12 22

Examples 1, 2, and 3 show that Rockwell hardness is low and flexibility is excellent. Also, the vibration acceleration is small. This indicates that resonance in the natural vibration region is small, and it is clear that the vibration absorption is excellent. Further, it can be seen that the decrease in the bending strength after the thermal history with respect to the normal bending strength is small and the heat resistance is excellent. On the other hand, Comparative Example 1 is inferior in flexibility and vibration absorption because of high hardness and high vibration acceleration. In addition, the bending strength after thermal hysteresis is greatly reduced with respect to the normal bending strength, and the heat resistance is poor. Comparative Example 2 is excellent in flexibility and vibration absorption because the hardness is low and the vibration acceleration is low. Although the bending strength after thermal history with respect to the normal bending strength is not as high as that of Comparative Example 1,
Significant decrease in strength and poor heat resistance. Comparative Example 3
The decrease in bending strength after thermal history with respect to normal bending strength is small, and the heat resistance is excellent. On the other hand, since the hardness is high and the vibration acceleration is high, flexibility and vibration absorption are poor.

[0026]

As is clear from the above examples, the phenolic resin composition obtained by the method of the present invention is excellent in flexibility, vibration absorption and heat resistance. Therefore, by using the phenolic resin composition according to the present invention, it is possible to obtain a molded article excellent in toughness, a friction material excellent in squealing characteristics, vibration absorption, and wear resistance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) (C08L 65/00 83:04)

Claims (4)

[Claims] 1. Penetration (JIS K 2530-1976)
As an essential component, a silicone gel based on an addition-reaction type silicone having a weight of -50 g) of 10 to 300, and an aromatic hydrocarbon-modified phenol resin obtained by polycondensing phenols and aromatic hydrocarbons are contained. A phenolic resin composition characterized in that: 2. Penetration (JIS K 2530-1976)
A silicone gel based on an addition-reaction type silicone having a weight of -50 g) of 10 to 300, and an aromatic hydrocarbon-modified phenol resin obtained by polycondensing phenols, aromatic hydrocarbons and aldehydes are essential. The phenolic resin composition according to claim 1, which is contained as a component. 3. The aromatic hydrocarbon is benzene, toluene,
3. The phenolic resin composition according to claim 1, which is at least one selected from xylene and mesitylene. 4. The method for producing a phenolic resin composition according to claim 1, wherein the silicone gel is kneaded with the aromatic hydrocarbon-modified phenolic resin using a pressure kneader.