Rubber composition for high-load transmission belt and high-load transmission belt from the rubber composition

• US 20050043486A1
• Filed: 04/23/2003
• Published: 02/24/2005
• Est. Priority Date: 04/23/2002
• Status: Active Grant

• Current Assignee: Bando Chemical Industries Limited
• Original Assignee: Bando Chemical Industries Limited
• Inventors: Okuno, Shigeki
• Granted Patent: US 7,189,785 B2
• Time in Patent Office: Days
• US Class Current: 525/193
• CPC Class Codes: C08K 5/01 Hydrocarbons C08K5/0091 takes precedence
• CPC Class Codes: C08K 5/098 Metal salts of carboxylic acids
• CPC Class Codes: C08K 7/02 Fibres or whiskers
• CPC Class Codes: C08L 21/00 Compositions of unspecified rubbers
• CPC Class Codes: C08L 23/16 Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
• CPC Class Codes: F16G 5/06 with reinforcement bonded by the rubber
• CPC Class Codes: F16G 5/166 with non-metallic rings F16G5/18 takes precedence

Abstract

This invention has an object of enhancing the cold resistance of a heavy duty power transmission V-belt without impairing its durability at high temperatures, ensuring its sufficient power transmission capability and concurrently enhancing its permanent set resistance. To attain the object, the invention employs, for a rubber element of the belt, a rubber composition in which 20 to 40 parts by weight of a metal salt monomer of an organic acid and 5 to 35 parts by weight of short fibers are mixed into 100 parts by weight of a rubber component composed of EPDM and HNBR in their ratio of 55/45 to 75/25, the rubber hardness measured with a durometer Type D is 40 to 60, the value of t₅ given by a Gehman torsion test is −50° C. to −35° C., and the amount of acetone extract from the rubber component is 9% or less.

Claims

1-9. -9. cancel

10. A rubber composition for a heavy duty power transmission belt, the rubber composition having a rubber hardness of 40 to 60 when measured with a durometer Type D, a value of t5 of −

50°

C. to −

35°

C. when given by a Gehman torsion test, and an amount of acetone extract of 9% or less, wherein;

(a) 20 to 40 parts by weight of a metal salt monomer of an organic acid is mixed into 100 parts by weight of a rubber component composed of an ethylene-α

-olefin elastomer and hydrogenated acrylonitrile butadiene rubber;

(b) 5 to 35 parts by weight of short fibers are mixed into 100 parts by weight of the rubber component; and

(c) the amount of the ethylene-α

-olefin elastomer in 100 parts by weight of the rubber component is 55 to 75 parts by weight.

11. The rubber composition for a heavy duty power transmission belt of claim 10, wherein the short fibers comprise organic short fibers with a tensile modulus of 15 GPa to 300 GPa, and 5 to 20 parts by weight of the organic short fibers are mixed into the rubber component.

12. The rubber composition for a heavy duty power transmission belt of claim 11, wherein the organic short fibers comprise at least one type of fibers selected from the group of poly(paraphenylene-terephthalamide) fibers, co-poly(paraphenylene-3,4′

-oxydiphenylene-terephthalamide) fibers, poly-(metaphenylene-isophthalamide) fibers, poly(paraphenylene-benzobisoxazole) fibers, polyvinyl alcohol fibers, and holaromatic polyester fibers.

13. A heavy duty power transmission cogged V-belt, wherein at least one of rubber elements constituting the belt is formed from the rubber composition of claim 10.

14. A heavy duty power transmission V-belt comprising:

a tension member formed of a rubber layer having a cord embedded thereinto; and

a plurality of blocks engaged at specified pitches and intervals in the lengthwise direction of the belt with the tension member,

wherein the rubber layer is formed from the rubber composition of claim 10.

15. The rubber composition for a heavy duty power transmission belt of claim 10, wherein the mixing ratio of oil per 100 parts by weight of the rubber component is 0 to 5 parts by weight, the ethylene-α

-olefin elastomer is of amorphous grade, the bound acrylonitrile content in the hydrogenated acrylonitrile butadiene rubber is 20% or less, and the metal salt monomer of the organic acid is zinc dimethacrylate or zinc diacrylate.