JP2000017465A - Rust preventive coating material backing metal coated with that rust preventive coating material for frictional member, and frictional member using that backing metal for frictional member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a frictional material which has a rust preventing effect with high reliability without depending on the use conditions and which suppresses screams of brakes by coating a backing metal for the frictional material with a rust preventing coating film containing a liquid resin, powdery rubber and calcium oxide, and further fixing the frictional member thereto. SOLUTION: As for the liquid resin, a liquid cashew modified resin or a liquid resin prepared by dissolving a solid resin such as an epoxy-modified novolac resin and phenol resin in a solvent is used. As for the powdery rubber, NBR, SBR, natural rubber or the like is used. The liquid resin (calculated as a solid content), powdery rubber and calcium oxide are compounded by 5 to 80 wt.%, 19 to 90 wt.% and 2 to 20 wt.%, respectively, and more preferably, 13 to 45 wt.%, 53 to 85 wt.% and 2 to 10 wt.%, respectively. The frictional material is produced by applying the rust preventive coating paste on the backing metal 2 for the frictional material, temporarily forming and baking, mounting the backing metal 2 of the frictional material with the face coated with the adhesive 3 upside, depositing the powder material for the frictional member 4, and forming into one body while heating and pressurizing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rust-proof coating material suitable for a friction material such as a disc brake pad and a brake lining used for braking an automobile, a railway vehicle, and the like, and a back metal for a friction material coated with a rust-proof coating material. And a friction material using a back metal for the friction material.

[0002]

2. Description of the Related Art For example, a disc brake is used as a braking device for an automobile or the like, and there is a disc brake pad as a braking member thereof. As a rust-proofing treatment of the back metal in the conventional disc brake pad, for example, as shown in JP-A-51-24533, the surface of the back metal is subjected to a chemical treatment such as nitriding treatment,
As shown in Japanese Patent Application Laid-Open No. 69618, it is generally known that a back metal is coated with an epoxy resin, a phenol aldehyde resin, or the like.

According to the method disclosed in JP-A-51-24533, it is possible to satisfy the requirements of the market with respect to the rust-preventive effect. However, in the method disclosed in JP-A-7-269618, the rust-preventive effect depends on the use conditions. Inferior. For example, the reliability is low for a long-time use in an environment where rust is likely to occur, such as a bad road containing salt water or a high-temperature wet area. Separately from the above, JP-A-51-24533 and JP-A-7-26
In the method disclosed in Japanese Patent No. 9618, a brake squeal called a squeal noise mainly occurs during the brake braking.

[0004]

SUMMARY OF THE INVENTION According to the first aspect of the present invention, there is provided a rust-proof coating material suitable for a friction material capable of suppressing a rust effect with high reliability and suppressing brake squeal regardless of use conditions. To provide. The second aspect of the present invention is to provide a friction material backing suitable for a friction material capable of suppressing the occurrence of brake squeal and a highly reliable anti-rust effect regardless of use conditions. The third aspect of the present invention is to provide a friction material capable of suppressing the occurrence of brake squeal and a highly reliable anti-rust effect regardless of use conditions.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a rust-preventive coating material containing a liquid resin, powder rubber and calcium oxide. The present invention also relates to a back metal for a friction material in which the surface on the side to which the friction member is fixed is coated with the above rust-preventive coating material. Further, the present invention relates to a friction material in which a friction member is fixed to a surface of the above-mentioned back metal for a friction material, which is coated with a rust-preventive film material.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A mixture containing a liquid resin, a powdered rubber and calcium oxide is used to obtain a rust preventive coating material of the present invention. Among them, a liquid resin is, for example, a liquid cashew resin or an epoxy-modified novolak resin. , A phenolic resin, an epoxy resin, a melamine resin, a urethane resin, a solid resin such as an alkyd resin is dissolved in a solvent such as methanol and methyl ethyl ketone, and a liquid resin is used.
As the powder rubber, for example, NBR, SBR, natural rubber and the like are used. The ratio of the liquid resin, powdered rubber and calcium oxide is 5 to 80% by weight of the liquid resin (as solid content), and the powder rubber is 19 to 90% by weight and the calcium oxide is 1 to 90% by weight.
It is preferably 20% by weight in terms of rust prevention effect and suppression of brake squeal.
More preferably, the powder rubber is 53 to 85% by weight and the calcium oxide is 2 to 10% by weight with respect to 3 to 45% by weight, and the powder rubber is 67 to 80% with respect to 17 to 30% by weight of the liquid resin (as solid content). % By weight and calcium oxide 3-6
More preferably, it is% by weight.

[0007] The viscosity of a mixture of liquid resin, powdered rubber and calcium oxide (paste for a rust preventive coating material) is 3 at 20 ° C.
It is preferably from 0 to 100 poise, more preferably from 45 to 85 poise, even more preferably from 60 to 70 poise. The thickness of the rust preventive coating material coated on the surface of the friction metal backing metal is 0.05 to
0.15 mm is preferable, 0.07 to 0.13 mm is more preferable, and 0.09 to 0.11 mm is further preferable. In the case of a friction material, preferably 0.02 to 0.05 mm, more preferably 0.025 to 0.045 mm,
0.03 to 0.04 mm is more preferable.

[0008] The material of the friction member fixed to the surface of the backing metal for the friction material coated with the rust-preventive coating material may be any of a semi-metallic type, a non-steel type, a metal type including a sintered body, and a C / C composite type. There is no particular limitation as well. As the material of the friction member, generally known materials are used, for example, steel fiber, brass fiber, copper fiber, aramid fiber, acrylic fiber, phenol fiber, ceramic fiber, rock wool, potassium titanate fiber, calcium silicate fiber , Fibrous substances such as carbon fibers, thermosetting resins such as phenolic resins, epoxy resins, melamine resins, and cashew resins; binders containing rubber compositions such as NBR and SBR; organic friction modifiers such as friction dust; Inorganic friction modifiers such as barium, calcium carbonate, and magnesium carbonate; rust inhibitors such as calcium hydroxide; lubricants such as graphite and molybdenum disulfide; and metals such as zinc, brass, and copper as needed. Flour is added.

The mixing ratio of the above-mentioned materials is appropriately selected depending on the material of the friction member, and is not particularly limited. For example, the content of the fibrous substance is preferably 35 to 65% by weight in the whole composition, and 40 to 50% by weight. More preferably, the content is 60% by weight. The content of the binder is 15 to 35% by weight in the total composition.
It is preferably contained, more preferably from 20 to 30% by weight. The content of the friction modifier is preferably 3 to 20% by weight, more preferably 5 to 15% by weight in the whole composition. The content of the rust inhibitor is preferably 1 to 8% by weight in the whole composition, and 2 to 6% by weight.
More preferably, it is contained by weight. The content of the lubricant is preferably 1 to 15% by weight in the whole composition,
More preferably, the content is 3 to 10% by weight. Further, the content of the metal powder to be added as needed is 3 to 3 in the total composition.
The content is preferably 15% by weight, more preferably 5 to 12% by weight. These components are blended so that the total composition becomes 100% by weight.

[0010] The friction material according to the present invention, for example, a disc brake pad, is obtained by mixing a material containing a liquid resin, powder rubber and calcium oxide to obtain a paste for a rust-preventive coating material. After applying to the surface of the back metal for the friction material to which the friction member is fixed, insert it into the temporary molding die,
Temporary molding is performed at a temperature of 100 to 150 ° C., and further, baking treatment is performed at a temperature of 140 to 200 ° C. for 10 to 120 minutes in a hot air drying oven. 10 ~ 30μ on the surface of anti-rust coating material after baking
m, and then insert a friction metal backing with the adhesive applied side up in a hot pressing mold,
After filling or laminating the friction member material powder or the friction member preform on the upper part thereof, integrally molding by heating and pressing molding method, fixing the friction material backing metal, the rust prevention coating material and the friction member, and then performing heat treatment. And by polishing the surface.

The heating temperature at the time of integral molding by the heat and pressure molding method is preferably 130 to 170 ° C., and 140 to 160 ° C.
C is more preferred. The pressure is preferably 30 to 60 MPa, more preferably 40 to 55 MPa. The heat treatment temperature in the subsequent step is preferably 100 to 300 ° C, and 150 to 250 ° C.
C is more preferred.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a disk brake according to an embodiment of the present invention.

[0013]

Embodiments of the present invention will be described below. Example 1 The components shown in Table 1 were blended, uniformly mixed with a mixer to obtain a friction material composition, and then preformed to obtain a friction material preform. On the other hand, epoxy-modified novolak resin (Cashew Corporation)
35% methanol in 65% by weight.
20% by weight of a resin solution dissolved by adding weight%, NBR powder (trade name: Nippol 1411, manufactured by Zeon Corporation) 7
5% by weight and 5% by weight of calcium oxide were stirred and mixed to obtain a paste for a rust-proof coating material having a viscosity of 65 poise. Next, after applying the paste for a rust-proof coating material to the surface of the back metal for the friction member on the side to which the friction member is fixed, the paste is inserted into a temporary molding die,
It was temporarily molded at 130 ° C. for 3 minutes, coated with a 0.1 mm thick rust preventive coating material, and further baked at 160 ° C. for 60 minutes in a hot air drying oven.

Thereafter, an adhesive (trade name: A344B, manufactured by Yokohama Rubber Co., Ltd.) is applied to the surface of the rust-preventive coating material to a thickness of 20 μm, and the surface on which the adhesive is applied faces up. The back metal is inserted into a hot-press molding die heated to 143 ± 5 ° C, and the friction member preform is placed on top of
After repeating the process of pressurizing for 5 seconds under the condition of a and releasing the gas for 5 seconds to perform degassing three times, a pressure of 40
The body was integrally molded by heating and pressing for 8 minutes under the condition of MPa. Then, after performing a heat treatment for 5 hours in a hot air drying oven at 200 ° C., the surface is polished and the rust-proof coating material 1 and the backing metal 2 for the friction material shown in FIG.
A disk brake pad composed of the adhesive 3 and the friction member 4 was obtained.

Comparative Example 1 A disc brake pad was obtained through the same steps as in Example 1, except that the surface of the backing metal for a friction member was not coated with a rust preventive coating material.

Comparative Example 2 25% by weight of the phenol / epoxy resin solution used in Example 1 and 75% by weight of NBR powder were mixed by stirring to obtain a viscosity of 6%.
A 5-poise paste for a rust preventive coating material was obtained. Example 1 below
Through the same steps as above, a disc brake pad was obtained.

[0017]

[Table 1]

Next, the disc brake pads obtained in Example 1 and the disc brake pads obtained in Comparative Examples 1 and 2 were immersed in a 5% by weight saline solution for 10 minutes, 23
One cycle was left in air at 120 ° C. and 30 minutes at 70 ° C. in drying, and after 500 cycles and 750 cycles, the rusting area in the shear plane was measured according to JIS D4415. As a result, the rusting area of the disc brake pad obtained in Example 1 was 0% for both 500 cycles and 750 cycles, but the rusting area of the disc brake pad obtained in Comparative Example 1 was 500 cycles. Of the disc brake pad obtained in Comparative Example 2 was 100% and the rust area was 0% in 500 cycles, but was 30 to 70% in 750 cycles.

Further, the disc brake pads obtained in Example 1 and the disc brake pads obtained in Comparative Examples 1 and 2 were examined for brake squeal.
As a result, the disc brake pads obtained in Example 1 and Comparative Example 1 did not generate brake squeal, but the disc brake pads obtained in Comparative Example 2 had a drawback that brake squeal occurred. In the test, the vehicle was run in an urban area (1000 km) using a real vehicle (vehicle weight: 1180 kg, brake type: collet type (cylinder area: 25 cm ² ), automatic vehicle), and the sensitivity was evaluated.

[0020]

According to the first aspect of the present invention, a rust-preventive coating material can provide a highly reliable rust-inhibiting effect and a friction material capable of suppressing the occurrence of brake squeal regardless of use conditions. The friction metal backing according to the second aspect can provide a friction material capable of suppressing the occurrence of brake squeal and a highly reliable anti-rust effect regardless of the use conditions. The friction material according to the third aspect is highly industrially suitable because it has a highly reliable rust preventive effect and can suppress the occurrence of brake squeal regardless of use conditions.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rust prevention coating material 2 Back metal for friction material 3 Adhesive 4 Friction member

Continued on front page F-term (reference) 3J058 BA21 BA23 BA28 CA47 FA01 FA21 GA07 GA15 GA26 GA28 GA35 GA37 GA45 GA50 GA55 GA92 GA95 4K062 AA01 BA14 BC04 BC06 BC11 BC12 BC13 BC15 CA02 CA04 EA02 FA03

Claims (3)

[Claims] 1. A rust preventive coating material containing a liquid resin, powder rubber and calcium oxide. 2. The method according to claim 1, wherein the surface on the side to which the friction member is fixed is provided.
A back metal for a friction material, which is coated with the rust-preventive film material described. 3. A friction material wherein a friction member is fixed to a surface of the back metal for a friction material according to claim 2, which is coated with a rust-proof coating material.