Nitrile rubber-based composition
A nitrile rubber-based composition comprising 1,000 to 2,500 parts by weight of a magnetic powder or silylated magnetic powder having a compressed density of 3.4 to 3.7 g/cm 3 , 0.5 to 20 parts by weight of alkoxyalkylsilane, and 8 to 40 parts by weight of a plasticizer, based on 100 parts by weight of nitrile rubber, hydrogenated nitrile rubber, or blend rubber thereof. The nitrile rubber-based composition that does not cause deterioration in roll processability and in adhesion between an adhesive applied to a metal plate and the rubber, even when a magnetic powder is added at a ratio as high as 1,000 parts by weight or more based on 100 parts by weight of nitrile rubber, hydrogenated nitrile rubber, or blend rubber thereof.
1 . A nitrile rubber-based composition comprising 2,000 to 2,500 parts by weight of a magnetic powder or silylated magnetic powder having a compressed density of 3.4 to 3.7 g/cm 3 , 10 to 20 parts by weight of alkoxyalkylsilane, and & 30 to 40 parts by weight of a plasticizer, based on 100 parts by weight of nitrile rubber, hydrogenated nitrile rubber, or blend rubber thereof.
2 . The nitrile rubber-based composition according to claim 1 , wherein the alkoxyalkylsilane is used at a ratio of 10 to 20 parts by weight based on the 2,000 to 2,500 parts by weight of the magnetic powder.
3 . The nitrile rubber-based composition according to claim 1 , wherein millable type nitrile rubber having a Mooney viscosity ML 1+4 (100° C.) of 20 to 50 is used.
4 . The nitrile rubber-based composition according to claim 1 , wherein a magnetic powder having two particle size distribution peaks at 1 to 2 μm and 2 to 4 μm is used.
5 . The nitrile rubber-based composition according to claim 1 , wherein the magnetic powder having a compressed density of 3.4 to 3.7 g/cm 3 is at least one of a ferrite magnet and a rare-earth magnet.
6 . The nitrile rubber-based composition according to claim 5 , wherein the ferrite magnet is a strontium ferrite or a barium ferrite.
7 . The nitrile rubber-based composition according to claim 1 , wherein alkoxyalkylsilane is trialkoxyoctylsilane.
8 . The nitrile rubber-based composition according to claim 1 , which is applied as a vulcanization molding material of rubber magnet for a sensor used in magnetic encoders.
9 . A rubber magnet for a sensor, which is a vulcanization-molded product of the nitrile rubber-based composition according to claim 8 .
10 . A magnetic encoder composed of the rubber magnet for a sensor according to claim 9 .
11 . The magnetic encoder according to claim 10 , which is used in an encoder part of a wheel speed sensor.
12 . The magnetic encoder according to claim 11 , wherein the encoder comprises an annular magnetic rubber molded product mounted on a support member capable of being attached to a rotating body, and single or multiple N pole and S pole are magnetized in the circumferential direction.
13 . A method for producing a rubber magnet for sensor, comprising vulcanizing a nitrile rubber-based composition in a mold to which a magnetic field is applied, wherein the composition comprises 2,000 to 2,500 parts by weight of a magnetic powder or silylated magnetic powder having a compressed density of 3.4 to 3.7 g/cm 3 , 10 to 20 parts by weight of alkoxyalkylsilane, and 30 to 40 parts by weight of a plasticizer, based on 100 parts by weight of nitrile rubber, hydrogenated nitrile rubber, or blend rubber thereof.