JPH107815A - Brake abrasion material and pad for disc brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a brake abrasion material and a pad for a disc brake excellent in preventing a squeak on braking and also in abrasion resistance, adhering property with a back metal and filling properties for a boss hole part. SOLUTION: This brake abrasion material 3 consists of a reinforcing fibrous material, a binder which contains a rubber-modified phenolic resin and a non- modified phenolic resin, a lubricating material, an abrasion adjusting material, and a filler. It is preferable to contain 10-80wt.% rubber-modified phenolic resin in the binder. The pad 1 for a disc brake is obtained by uniformly forming an abrasion material 3 having the binder containing the rubber-modified phenolic resin with a back metal 2 by an adhesive layer 4 consisting of an epoxy resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake friction material and a disc brake pad used for an automobile or the like.

[0002]

2. Description of the Related Art Conventionally, metal fibers, ceramic fibers,
Brake friction materials composed of reinforcing fiber materials such as organic fibers, binders such as unmodified phenolic resins, lubricants such as graphite and molybdenum disulfide, friction modifiers such as cashew dust, and fillers such as barium sulfate. Are known.

[0003]

However, although the brake friction material using a phenolic resin such as an unmodified phenolic resin as a binder has excellent abrasion resistance, squealing occurs during braking by sliding against a disk rotor. There was a problem that it was easy.

The present invention has been made in view of the above circumstances, and is excellent in both prevention of squeal during braking and abrasion resistance, as well as in adhesiveness to a backing metal, filling in a boss hole portion, and the like. It is an object to provide an excellent brake friction material and a pad for a disc brake.

[0005]

The brake friction material of the present invention comprises a reinforcing fiber material, a binder, a lubricant, a friction modifier, a filler and the like, and the binder is composed of a rubber-modified phenol resin and an unmodified phenol resin. And a resin.

A disc brake pad according to the present invention is a disc brake pad obtained by bonding a brake friction material made of a reinforcing fiber material, a binder, a lubricant, a friction modifier, a filler, and the like, and a back metal with an adhesive. A pad, wherein the binder comprises a rubber-modified phenolic resin, and the adhesive is an epoxy resin.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The brake friction material of the present invention comprises a reinforcing fiber material, a binder, a lubricant, a friction modifier, a filler and the like, and the binder comprises a rubber-modified phenolic resin and an unmodified phenolic resin. Is included.

The reinforcing fiber material includes metals such as copper fiber, ceramic fiber, potassium titanate fiber, aramid fiber, and carbon fiber, and inorganic and organic fibers. A preferable content of the reinforcing fiber material is about 10 to 40% by weight based on the brake friction material, and the material reinforces the brake friction material by reinforcing a binder or the like. Examples of the lubricant include graphite, molybdenum disulfide and the like, friction adjusting materials such as cashew dust and ceramic powder, fillers such as barium sulfate, calcium carbonate and mica, and pH adjusting materials such as calcium hydroxide.

The binder is used to bind a reinforcing fiber material, a lubricant, a friction modifier, a filler, and the like. The binder of the brake friction material of the present invention is a rubber-modified phenol resin and an unmodified phenol resin. At least.

[0010] The rubber-modified phenol resin is a phenol resin modified with a rubber component, such as an acrylic rubber-modified phenol resin and a silicone rubber-modified phenol resin. The rubber-modified phenol resin preferably contains a rubber component in an amount of 10 to 50% by weight.
Two or more rubber-modified phenol resins having different molecular weights may be used. Since the binder of the brake friction material of the present invention is composed of a soft cured portion of a rubber-modified phenolic resin and a hard cured portion of an unmodified phenolic resin, the brake friction material of the present invention has abrasion resistance. Excellent both in preventing squeal during braking.

An unmodified phenolic resin is a phenolic resin that is not substantially modified with a rubber component,
For example, hexamethylenetetramine in novolak
It is a two-step phenolic resin obtained by adding 10%, and when the brake friction material is heat-compressed, not only the unmodified phenolic resins react with each other to crosslink and cure, but also the rubber-modified phenolic resin. It has the property of reacting, crosslinking and curing. As an unmodified phenolic resin,
Two or more compounds having different molecular weights may be used.

[0012] If the binder friction material contains a rubber-modified phenolic resin and an unmodified phenolic resin in an amount of 5 to 25% by weight as a binder, a fiber material, a lubricating material and the like can be easily bound. The material has excellent heat resistance. Further, in the total amount of the binder, 10% of the rubber-modified phenol resin is contained.
When it is present in an amount of up to 80% by weight, preferably 30 to 60% by weight, the brake friction material is particularly excellent in both abrasion resistance and prevention of squeal during braking.

In the binder of the brake friction material of the present invention,
In addition to rubber-modified phenolic resin and non-modified phenolic resin, phenolic resin modified with oils such as silicon-modified phenolic resin, oil-modified phenolic resin, cashew-modified phenolic resin, and oleic acid (the side chain of the resin has a double bond ), And one or more phenolic resins selected from the group consisting of: As these phenolic resins, those having a different molecular weight from the rubber-modified phenolic resin or the unmodified phenolic resin can be used.

The brake friction material of the present invention is prepared by charging a mixture comprising a reinforcing fiber material, a lubricant, a friction modifier, a filler, a rubber-modified phenolic resin, an unmodified phenolic resin, and the like, and subjecting the mixture to heat compression molding. It can be produced by reacting a rubber-modified phenolic resin with an unmodified phenolic resin and curing the resin.

FIG. 1 is a sectional view showing an example of a disc brake pad according to the present invention. The disc brake pad 1 is a brake made of a reinforcing fiber material, a binder, a lubricant, a friction modifier, a filler and the like. A disc brake pad formed by bonding a friction material 3 and a back metal 2 using an adhesive (adhesive layer) 4, wherein the binder includes a cured product of a rubber-modified phenol resin, and the adhesive 4 is an epoxy. It is a resin. The binder in the brake friction material 3 of the present invention is a cured product of a rubber-modified phenol resin having a side chain having a double bond or a phenol modified with an oil or fat such as oleic acid having a side chain having a double bond. When a cured resin is included, the back metal 2 and the brake friction material 3 are firmly adhered to each other by the epoxy resin.

[0016]

Hereinafter, the present invention will be described in detail. In the following test examples, all parts mean parts by weight. -Test Examples 1 to 5-10 parts of copper fiber, 10 parts of ceramic fiber, 5 parts of potassium titanate fiber and 5 parts of aramid fiber were used as a reinforcing fiber material (30 parts in total), and graphite 10 was used as a lubricant.
Parts, 5 parts of molybdenum disulfide, 5 parts of cashew dust as a friction modifier, 5 parts of ceramic powder, 20 parts of barium sulfate as a filler, 1 part of calcium hydroxide as a pH adjuster, and other additions 10 parts of the material were mixed with 14 parts of a phenol resin for a binder, mixed and dried to obtain a mixture. As shown in Table 1, as a phenol resin,
Five kinds of mixtures were prepared in which the mixing ratio of the acrylic rubber-modified phenolic resin and the straight (unmodified) phenolic resin was changed. As the acrylic rubber-modified phenol resin, "AR-100" manufactured by Sumitomo Durres (containing about 10% by weight of a chemically bonded acrylic rubber component in the acrylic rubber-modified phenol resin) was used. The product name "PR311" manufactured by Sumitomo Durres was used.

Next, the mixture is heat-compressed at 155 to 165 ° C. to react the acrylic rubber-modified phenolic resin with the straight-based phenolic resin, the straight-based phenolic resin alone, or the acrylic rubber-modified phenolic resin alone. And cured to obtain a brake friction material using a cured product of these phenolic resins as a binder.
The taken out brake friction material was heat-treated at 200 ° C. for 6 hours, polished and grooved to prepare a desired brake friction material. Physical properties such as abrasion resistance of the brake friction material manufactured as described above were measured according to JASO standard JASO.
Tested according to C-427,444. In addition, the frequency of occurrence of abnormal noise can be measured by various combinations of friction temperature and fluid pressure using a bench tester.
The test was performed with 000 braking operations. The test results are shown in Table 1 together with the formulation.

[0018]

[Table 1]

According to the results of the noise generation frequency shown in Table 1,
The frequency of the abnormal noise was determined by acrylic rubber-modified phenolic resin 4.
In the case of Test Example 2 in which a cured product of a reaction product of 10 parts of a straight phenol resin was used as a binder, the content was 0.2%, and in Test Example 4 in which a cured product of only 14 parts of a straight phenol resin was used as a binder. In this case, it was 15%. Also, from Table 1, the occurrence frequency of abnormal noise was 0% in Test Examples 1 and 3 obtained by using 7 parts and 10 parts of acrylic rubber-modified phenol resin in combination. That is, the frequency of occurrence of abnormal noise of the brake friction material using the acrylic rubber-modified phenolic resin and the straight phenolic resin as the binder was extremely low.

According to the results of the porosity shown in Table 1, the porosity was 6 to 7% in Test Example 2 using a phenol resin composed of 4 parts of an acrylic rubber-modified phenol resin and 10 parts of a straight phenol resin. In the case of Test Example 4 using 14 parts of the straight phenol resin alone, 4%
Met. Also, from Table 1, it can be seen that the porosity is as high as 6 to 8% when the binder is formed by using 4 parts or more of the acrylic rubber-modified phenol resin. The high porosity of 6 to 8% suggested that the vibration was attenuated and squeal noise was reduced.

According to the results of the amount of wear at each temperature shown in Table 1,
The amount of wear at 500 ° C. was 1.35 mm in the case of Test Example 1 in which a cured material of 7 parts of an acrylic rubber-modified phenol resin and 7 parts of a straight phenol resin was used as a binder.
In the case of Test Example 5 in which a cured product of only 14 parts of an acrylic rubber-modified phenol resin was used as a binder, the diameter was 2.60 mm. That is, when the acrylic rubber-modified phenol resin and the straight phenol resin were used as the binder, the abrasion resistance was improved as compared with Test Example 5 in which only the acrylic rubber-modified phenol resin was used as the binder.

Test Examples 6 to 8 Disc brake pads shown in FIG. 1 were manufactured as follows. Copper fiber, ceramic fiber, and aramid fiber are used as reinforcing fiber materials (total of 20 parts), and 10 parts of lubricant such as molybdenum disulfide, 20 parts of friction modifier such as cashew dust, barium sulfate, and pH modifier are used. 40 parts or 35 parts of calcium hydroxide or other additives, and 10 parts or 15 parts of phenol resin for the binder.
Parts were mixed so that the total mixing amount was 100 parts, and then the mixture was dried to obtain a mixture of the compositions of Test Examples 6 to 8 shown in Table 2. As shown in Table 2, as the phenol resin, only an acrylic rubber-modified phenol resin or only an unmodified phenol resin was used. Next, the mixture was subjected to cold compression molding at a normal temperature and a pressure of 3 to 5 MPa using a predetermined mold to obtain a brake friction material 3.

On the other hand, the back metal 2 was washed, coated with an epoxy resin adhesive, and dried. Then, the brake friction material 3
And the back metal 2 to which the adhesive has been applied is put into a predetermined mold and subjected to heat compression molding, and the brake friction material 3 and the back metal 2 are bonded to each other with an epoxy resin adhesive 4 to obtain a disc brake pad 1. Was. The molding pressure at this time was 4MP.
a, The molding temperature was about 160 ° C. The disc brake pad 1 taken out of the mold was heat-treated at 200 ° C. for 6 hours, and polished and grooved to obtain a target disc brake pad 1. The friction coefficient and the like of the obtained disc brake pad 1 were measured. Table 2 shows the results of these measurements together with the formulation.

[0024]

[Table 2]

When the bonding strength between the brake friction material 3 and the back metal 2 was tested for the disc brake pad 1, the bonding strength in Test Example 6 using 10 parts of an acrylic rubber-modified phenolic resin as a binder was 5 to 6 MPa. On the other hand, the adhesive strength of Test Example 7 using 10 parts of unmodified phenolic resin as a binder is 2-3 MPa, and the adhesive strength of Test Example 8 using 15 parts of unmodified phenolic resin as a binder is 1 to 3.
It was 2.5 MPa. That is, the brake friction material using the acrylic rubber-modified phenolic resin as the binder has a superior adhesive strength between the brake friction material 3 and the back metal 2 as compared with the one using the unmodified phenolic resin as the binder.

According to the result of the filling ratio of the boss hole portion shown in Table 2, the filling ratio of the boss hole portion in Test Example 6 in which a cured product of 10 parts of an acrylic rubber-modified phenol resin is used as a binder is 100%. The filling rate of the boss hole portion in Test Example 7 using 10 parts of the unmodified phenol resin was 30%. In addition, the filling rate of the boss hole portion in Test Example 8 in which the amount of the unmodified phenol resin was increased to 15 parts was 100%, but the porosity was as low as 4%.
In addition, it was found that the coefficient of friction decreased at high temperatures, resulting in inferior friction characteristics. That is, when the amount of the phenol resin used was the same, it was found that when the acrylic rubber-modified phenol resin was used, the boss hole portion filling rate and the like were good. If the boss hole is filled well, it is not necessary to form a separate piece or a two-layer structure, which is advantageous in terms of the manufacturing cost of the disc brake pad. In addition, the brake friction characteristics of the disc brake pads of Test Examples 6 to 8 were measured according to JASO C-
Measured according to 406.

From the results of Test Examples 6 to 8 above, the disc brake pad 1 using an acrylic rubber-modified phenolic resin as a binder has a larger brake than the disc brake pad using an unmodified phenolic resin as a binder. It was found that the disc brake pad was excellent in the adhesive strength between the friction material 3 and the back metal 2 and in the filling rate of the boss hole portion, and had a high porosity and was less likely to cause squealing.

[0028]

As described above, in the brake friction material of the present invention, since the binder contains a rubber-modified phenolic resin and an unmodified phenolic resin, it is possible to prevent squealing during braking and improve wear resistance. Excellent balance of performance. Further, in the disc brake pad of the present invention, since the binder contains a rubber-modified phenolic resin, the back metal and the brake friction material are firmly bonded with an epoxy adhesive.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a disc brake pad according to an embodiment of the present invention.

[Explanation of symbols]

1. Pad for disc brake, 2. Back metal, 3.
Brake friction material, 4 ... adhesive layer, 5 ... boss

Claims (2)

[Claims] 1. A brake friction material comprising a reinforcing fiber material, a binder, a lubricant, a friction modifier, a filler, and the like, wherein the binder comprises a rubber-modified phenolic resin and an unmodified phenolic resin. . 2. A disc brake pad obtained by bonding a brake friction material made of a reinforcing fiber material, a binder, a lubricant, a friction modifier, a filler, and the like to a back metal using an adhesive. The material contains a rubber-modified phenolic resin,
A pad for a disc brake, wherein the adhesive is an epoxy resin.