JPS6031585A - Resin composition for friction material - Google Patents

Abstract

PURPOSE:To provide a resin compsn. in powder for friction material, which contains a modified novolac phenol resin, an isocyanate compd. and hexamethylenetetramine, is excellent in friction characteristics, heat resistance and durability, is fast curing and has good formability. CONSTITUTION:An aromatic hydrocarbon resin-modified novolac phenol resin is prepd. by reacting 100pts.wt. phenol with about 5-100pts.wt. aromatic hydrocarbon resin in the presence of an acidic catalyst and then adding formaldehyde for interaction. The resin compsn. for friction material is obtained by blending 100pts.wt. the above modified novolac phenol resin, about 0.5-10pts.wt. isocyanato group-contg. compd. [e.g. 2,2-bis(4,4'-dicyanato-diphenyl)propane] and about 1-30pts.wt. hexamethylenetetramine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new and useful resin composition for friction materials, and more specifically, it has excellent friction properties, heat resistance, and durability, and is quick to cure and has good moldability. The present invention relates to a powdered resin composition for friction materials.

A mixed powder of phenolic resin and hexamethylenetetramine has traditionally been used as a resin composition for brake linings, and cashew oil-modified phenol novolak resin is well known as a phenolic resin, but recently Due to durability problems depending on usage conditions, aromatic hydrocarbon resin-modified phenol novolak resins, which have excellent heat resistance and durability, are gradually replacing cachet-modified phenol novolac resins.

However, aromatic hydrocarbon resin-modified novolac phenol resins have problems in moldability due to slow curing and low productivity, and improvements are currently being sought. There are methods to speed up curing, such as increasing the molecular weight of the resin and reducing the amount of modification of the aromatic hydrocarbon resin, but the former causes problems in manufacturing because the melt viscosity increases. However, the latter has the disadvantage that it cannot provide satisfactory performance. Another method is to speed up curing by converting novolac phenol resin to high orthorectinization using a divalent metal salt catalyst, etc. (Japanese Patent Publication No. 43-21753
No. 2) has also been proposed, but it has not yet achieved a satisfactory curing speed.

However, as a result of extensive research into a resin composition for friction materials that does not have the above-mentioned drawbacks, the present inventors have found that the conventional aromatic hydrocarbon resin-modified novolak phenol resin and hexamethylenetetramine further contain a cyanate group. The present inventors have discovered that a resin composition obtained by adding a compound has excellent friction properties, heat resistance, and durability, and is quick to cure (and has good moldability), leading to the completion of the present invention. - That is, the present invention provides a powder resin composition for friction materials, which is characterized by containing an aromatic hydrocarbon 4I4 lipid-modified novolac phenol resin, a compound having a cyanate group, and hexamethylenetetramine.

Since the resin composition for friction materials of the present invention contains a cyanate group-containing compound and hexamethylenetetramine, it is not only crosslinked and cured by conventional hexamethylenetetramine, but also has phenolic hydroxyl groups (-011 ) and the cyanate group (-0CN) react with each other when heated, two types of crosslinking reactions occur, and it can be judged that curing progresses quite rapidly.

The novolak phenol resin used in the present invention includes raw material phenols such as phenol, cresol, resorcinol, bisphenol A, bisphenol A oligomer, etc., and raw material phenols such as their equivalent substances;
Examples of aromatic hydrocarbon resins include conventional novolac phenol resins obtained by reacting formaldehyde supplying substances such as formaldehyde, paraformaldehyde, hexamethylenetetramine, butyraldehyde, or equivalent substances thereof, by a known and commonly used method. Examples include benzene/formaldehyde resin, toluene/formaldehyde resin, xylene/formaldehyde resin, methylene/formaldehyde resin, or mixed alkylbenzene/formaldehyde resin obtained from various alkylbenzene raw materials.

A common method for obtaining aromatic hydrocarbon resin-modified novolac phenol resin is to react the aromatic hydrocarbon resin and raw material phenols under an acidic catalyst, then add a formaldehyde supply substance and react. However, after reacting the raw material phenols and the formaldehyde supply substance, the aromatic hydrocarbon resin may be added and the reaction may be carried out, or these three components may be added and reacted at the same time.

The acidic catalyst used here typically includes inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid, and organic acids such as valatoluenesulfonic acid, oxalic acid, and acetic acid, which may be used alone or in combination.

The amount of aromatic hydrocarbon resin used is 10% of the raw material phenols.
Usually 5 to 100 parts by weight per 0 parts by weight, or 3 parts by weight
The range is from 0 to 70 parts by weight, and if this amount exceeds 1'00 parts by weight, the resin will harden slowly, reducing the productivity of the friction material. If the amount is less than 100%, the desired performance for the present invention cannot be obtained, and therefore it is not preferable.

Compounds having a cyanate group used in the present invention include:
It must be a solid that can be crushed at room temperature, such as 2.2-bis(4,4'-dicyanatodiphenyl)propane, 4.4'-dicyanatodiphenyl, 1.3.6
- Aromatic cyanate ester such as doricyanatonaphthalene? 41, cyanate group-containing triazine compounds such as BT resin [cyanate group-containing bismaleimide/triazine resin manufactured by Mitsubishi Gas Chemical a grade], etc.; however, if the compound is a crushable solid and has a cyanate group, these can be used. It is not limited.

The amount of the compound having a cyanate group used is usually 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of aromatic hydrocarbon resin-modified novolac phenol 4Bi fat. If the amount is less than 0.5 parts by weight, the effect of increasing the curing speed cannot be obtained;
Even if more than one part by weight is added, no further effect can be obtained, which is not preferable.

In the present invention, the amount of hexamethylenetetramine used together with the aromatic hydrocarbon resin-modified novolak phenol resin and the compound having a cyanate group is 1 to 30 parts by weight, preferably 3 to 30 parts by weight, based on 100 parts by weight of the modified novolak phenol resin. The amount is in the range of 10 parts by weight, and if the amount is less than 1 part by weight, the curing speed will be slow, and if it exceeds 30 parts by weight, the amount of gas generated during curing will increase, so both are not preferred.

The resin composition for friction materials of the present invention is usually obtained by mixing and pulverizing an aromatic hydrocarbon resin-modified novolak phenol resin, a compound having a cyanate group, and hexamethylenetetramine in a predetermined ratio. may be mixed after being ground.

The thus obtained resin composition for friction materials of the present invention comprises friction base materials such as asbestos and glass, cachet dust,
After being uniformly mixed in a mixer with friction modifiers such as barium sulfate, copper powder, and calcium carbonate, it is hot-pressed in a shorter time and more efficiently than conventional methods, and then fired and polished to obtain a polished 1β material. This friction material exhibits good wear resistance and a high coefficient of friction over the entire temperature range of use, and is also excellent in stability, making it particularly suitable as a resin composition for brake linings.

The present invention will be specifically explained below using Examples and Comparative Examples. In addition, all parts and percentages in the examples are based on weight.

Example 1 100 parts of Nicanoru (xylene formaldehyde resin manufactured by Mitsubishi Gas Chemical e@) and 200 parts of phenol were mixed with 0.2 parts of para-toluenesulfonic acid as a catalyst, and 12
React at 0°C for 2 hours. Next, 1 part of oxalic acid and 3 parts
90 parts of 7% formalin was added thereto and reacted at 100°C for 2 hours, then heated to 180°C to dehydrate, and further dehydrated under reduced pressure to obtain a modified novolac phenol resin with a softening point of 105°C.

This tree J] 100 parts of I+, 8 parts of hexamethylenetetramine, and 33 parts of [1T-2300 (bismaleimide-triazine resin manufactured by Mitsubishi Gas Chemical @1) were mixed and ground to form a powdered resin composition for friction materials of the present invention. This resin composition cured quickly and had excellent properties.

Example 2 A powdered friction material resin composition of the present invention was obtained in the same manner as in Example 1 except that 4,41-dicyanatodiphenyl was used instead of BT-2300. This 4-11 composition cured quickly (and had excellent properties).

Example 3 A resin composition for a powder friction material of the present invention was obtained in the same manner as in Example 1 except that the amount of hexamethylenetetramine used was changed to 4 parts. This resin composition cured quickly and had excellent properties.

Example 4 A modified novolac phenol resin having a softening point of 105° C. was obtained in the same manner as in Example 1, except that Nikalu-H (Mesidilene formaldehyde resin manufactured by Mitsubishi Gas Chemical Company) was used instead of Nicanol-11. 100 parts of this resin, 8 parts of hexamethylenetetramine, and 3 parts of BT-23000 were mixed and pulverized to obtain a resin composition for a friction material according to 15) of the present invention. This resin composition cured quickly and had excellent properties.

Example 5 100 parts of Nicaru ■ and 200 parts of phenol are reacted at 120° C. for 2 hours using 0.1 part of sulfuric acid as a catalyst. Next, 70 parts of 37% formalin, 15 parts of cachet shell polymerized oil, and 0.5 parts of oxalic acid were added and reacted at 100°C for 2 hours, then heated to 180°C for dehydration, and further dehydrated under reduced pressure. A modified novolac phenol resin having a softening point of 104°C was obtained.

100 parts of this resin, 8 parts of hexamethylenetetramine, and B
A powdered friction material resin composition of the present invention was obtained by mixing and pulverizing 33 parts of T-2100 (bismaleimide triazine resin manufactured by Mitsubishi Gas Chemical QW).This resin composition cures quickly and has excellent properties. It had a

Example 6 Example 1 except that the amounts of Nicanoru 11 and 37% formalin were changed to 60 parts and 100 parts, respectively.
A modified novolac phenol resin having a softening point of 104°C was obtained in the same manner as above. 10Q parts of this resin, 6 parts of -hexamethylenetetramine, and 2 parts of 1.3.6-1-lycyanatonaphthalene were mixed and crushed to obtain a powdered resin composition for friction materials of the present invention. This resin composition cured quickly and had excellent properties.

Comparative Example I A resin composition for a friction material was obtained in the same manner as in Example 1 except that the addition of BT-2300 was omitted. This 4! I
The fat composition cured slowly.

Comparative Example 2 The amount of hexamethylenetetramine used was changed to 4 parts, and B
A powdered resin composition for a friction material was obtained in the same manner as in Example 1 except that the addition of T-2300 was omitted. This resin composition cured extremely slowly.

Comparative Example 3 A powdered resin composition for a friction material was obtained in the same manner as in Example 4 except that the addition of BT-2300 was omitted. This resin composition cured slowly.

Comparative Example 4 100 parts of phenol and 65 parts of 37% formalin were reacted at 100°C for 2 hours using 0.5 parts of oxalic acid as a catalyst. Thereafter, the mixture was heated to 180°C for dehydration, and further under reduced pressure. It was dehydrated to obtain a modified novolac phenol resin with a softening point of 106°C. 100 parts of this resin and 8 parts of hexamethylenetetramine were mixed and ground to obtain a powdered resin composition for friction materials. Its properties as a material were poor.

Comparative Example 5 A cashew oil-modified novolak phenol resin with a softening point of 104° C. was obtained by reacting in the same manner as in Comparative Example 4 except that the amount of 37% formalin used was changed to 70 parts and 15 parts of cashew shell polymerized oil was added. Next, a powdered resin composition for a friction material was obtained in the same manner. This resin composition had poor properties as a friction material.

Comparative Example 6 1.3.6-) A powdered resin composition for a friction material was obtained in the same manner as in Example 6 except that the addition of lycyanatonaphthalene was omitted. This resin composition cured slowly.

Test Example 1 The melting points of the resin compositions for friction materials obtained in Examples 1 to 6 and Comparative Examples 1 to 6 were measured by the capillary method, and the fluidity and gelation time were measured according to JIS K-6910.

The results are shown in Table 1.

Test Example 2 18 parts of the resin composition for friction materials obtained in Example 1.2.4.5 and Comparative Example 1.3.4.5, 6 parts of short fiber asbestos
5 parts, cachet dust 8 parts, barium sulfate 7 parts, copper powder 2
160℃, 200 kg/cl,
After hot-press molding for 10 minutes, it was fired at 180°C for 8 hours and polished to obtain a friction material test piece measuring 25 mm x 25 m x 5 m, and its friction coefficient and wear rate were measured according to JISD-4411. The results are shown in Table 1.

Procedural amendment September 1, 1980 Mr. Manabu Shiga, Commissioner of the Patent Office■, Indication of the case 1982 Patent Application No. 136853 2, Name of the invention Resin composition for friction material 3, Person making the amendment Related Patent applicant: 35-58 Sakashita, Karuhashi-ku, Tokyo 174 (28
B) Dainippon Ink & Chemicals Co., Ltd. Representative: Shigeru Kuni Mura 4, Agent Address: 3-7-20 Nihonbashi, Chuo-ku, Tokyo 103 Dainippon Ink & Chemicals Co., Ltd. Phone: Tokyo (03) 272-4511 (Dainippon Ink & Chemicals Co., Ltd.) Representative) 6
, Contents of amendment +11 Change [methylene/formaldehyde resin] from the bottom 6 lines of page 3 of the specification to "mesitylene/formaldehyde resin"
Corrected to formaldehyde resin J.

Claims (1)

[Claims] A powder resin composition for a friction material, comprising an aromatic hydrocarbon resin-modified novolak phenol resin, a cyanate group-containing compound, and hexamethylenetetramine.