ARTICLE AND RUBBER COMPOSITION CONTAINING BISMALEIMIDE

Abstract

The present invention is directed to an article of manufacture, in one case a pneumatic tire. having at least one cord-reinforced rubber component comprising (A) a reinforcing cord; and (B) a rubber composition contacting the cord, the rubber composition comprising (1) from 70 to 100 phr of at least one polyisoprene rubber selected from the group consisting of natural rubber or synthetic polyisoprene; (2) from 0 to 30 phr of at least one additional rubber selected from the group consisting of polybutadiene and styrene-butadiene rubber; (3) from 20 to 80 phr of carbon black; (4) from 2 to 10 phr of silica; (5) from 0 to 1 phr of a cobalt salt; and (6) from 0.5 to 5 phr of N, N′-m-phenylene bismaleimide; wherein the rubber composition excludes resins and silane coupling agents.

Claims

1. An article of manufacture having at least one cord-reinforced rubber component comprising (A) a reinforcing cord; and (B) a rubber composition contacting the cord, the rubber composition comprising (1) from 70 to 100 phr of at least one polyisoprene rubber selected from the group consisting of natural rubber or synthetic polyisoprene; (2) from 0 to 30 phr of at least one additional rubber selected from the group consisting of polybutadiene and styrene-butadiene rubber; (3) from 20 to 80 phr of carbon black; (4) from 2 to 10 phr of silica; (5) from 0 to 1 phr of a cobalt salt; and (6) from 0.5 to 5 phr of N, N′-m-phenylene bismaleimide; wherein the rubber composition excludes resins and silane coupling agents.

2. The article of manufacture of claim 1, wherein the rubber composition excludes the cobalt salt.

3. The article of manufacture of claim 1, wherein the rubber composition further comprises a curative package comprising from 2 to 10 phr of sulfur, from 1 to 12 phr of zinc oxide, from 0.5 to 2 phr of a sulfeneamide accelerator, and from 0 to 0.5 phr of zinc dimethyl dithiocarbamate.

4. The article of manufacture of claim 1, wherein the rubber composition further excludes N,N′-m-xylylene biscitraconimide.

5. The article of manufacture of claim 1, wherein the reinforcement cord comprises at least one cord selected from the group consisting of steel cords and polymeric cords.

6. The article of manufacture of claim 1, wherein the reinforcement cord is a steel cord.

7. The article of manufacture of claim 1, wherein the reinforcement cord comprises at least one polymeric cord selected from the group consisting of polyester cords, polyamide cords, polyaramid cords, polyketone cords, and rayon cords.

8. The article of manufacture of claim 1, wherein the article is a pneumatic tire and the cord-reinforced rubber component is a carcass ply.

9. The article of manufacture of claim 1, wherein the article is a pneumatic tire and the cord-reinforced rubber component is a belt.

10. The article of manufacture of claim 1 in the form of a pneumatic tire, a power transmission belt, hose, track, air sleeve, or conveyor belt.

Description

EXAMPLE 1

[0053] In this example, the effect of replacing a cobalt salt and in-situ resin with a m-phenylene bismaleimide is demonstrated in wirecoat rubber compounds. Three experimental rubber compounds were prepared in a lab Banbury mixer as indicated in Table 1, with all compounds containing otherwise identical amounts of additives in conventional amounts. Physical properties of the compounds were evaluated as indicated in Table 2.

TABLE-US-00001 TABLE 1 Sample No. 1 2 3 Natural Rubber 90 90 90 Synthetic Polyisoprene 10 10 10 Carbon Black 57 57 63 Silica 8.83 8.83 8.83 Resorcinol 4 4 0 HMMM 4.17 4.17 0 N,N′-m-phenylene bismaleimide 0 0 2 Sulfur 5 5 6.5 Sulfenamide 0.75 0.75 1.3 Cobalt Salt 0.5 0 0

TABLE-US-00002 TABLE 2 Sample No. 1 2 Sample Type.sup.1 Cont Inv 3 Stress-strain ATS (cured 18 minutes at 150° C.; test at 23° C.) Tensile strength (MPa) 20.4 20.8 21.1 Elongation at break (%) 387 421 395 100% modulus (MPa) 4.7 4.1 4.4 300% modulus (MPa) 15.8 14.6 16.5 Rebound, 23° C. (%) 41 41 42 Rebound, 100° C. (%) 54 53 57 Tear strength.sup.2 (cured 25 minutes at 150° C.; test at 23° C.) Tear strength, N/10 mm 231 299 263 Processing Uncured G′ 206 214 200 Stiffness G′ @ 10% strain, 90° C., ARES 3653 3167 3679 Hysteresis Tan D @ 90° C., 10% Strain 0.201 0.206 0.139 Wire Adhesion.sup.3 (cured 35 minutes at 155° C.; test at 23° C.) No aging, N 666 619 686 Rubber coverage, % 90 75 80 Aged 10 days in H.sub.2O at 90° C., N 671 575 779 Rubber coverage, % 75 55 85 Aged 20 days in H.sub.2O at 90° C., N 767 418 879 Rubber coverage, % 95 10 80 Aged 10 days in N.sub.2 at 120° C., N 604 649 798 Rubber coverage, % 85 95 95 .sup.1Cont = control; inv = inventive .sup.2The hot tear resistance property (tear strength) determination is conducted for peel adhesion of a sample to another sample of the same material. A description may be found in ASTM D4393 except that a sample width of 2.5 cm is used and a clear Mylar plastic film window of a 5 mm width is inserted between the two test samples. It is an interfacial adhesion measurement (pulling force expressed in N/mm units) between two layers of the same tested compound which have been co-cured together with the Mylar film window therebetween. The purpose of the Mylar film window is to delimit the width of the pealed area. .sup.3Standard wire and textile cord adhesion tests (SWAT) were conducted by embedding a single cord in the respective rubber compositions with an embedment length of 10 mm. The rubber articles were then cured as indicated. The cord in these rubber compositions were then subjected to a pull-out test, according to ASTM Standard D2229-73 with a pulling speed of 12.5 mm/min.

EXAMPLE 1

[0054] In this example, the effect of replacing a cobalt salt and in-situ resin with a m-phenylene bismaleimide is demonstrated in plycoat rubber compounds. Two experimental rubber compounds were prepared in a lab Banbury mixer as indicated in Table 3, with all compounds containing otherwise identical amounts of additives in conventional amounts. Physical properties of the compounds were evaluated as indicated in Table 4.

TABLE-US-00003 TABLE 3 Sample No. 4 5 Styrene-Butadiene Rubber 20 20 Natural Rubber 80 80 Carbon Black 43 43 Reactive Phenol-Formaldehyde Resin 1 0 HMMM 1.8 0 N,N′-m-phenylene bismaleimide 0 1 Non-reactive tackifier resin 1 1 Oil 10 5 Antidegradant 1 2 Zinc Oxide 2 2 Sulfur 3 3 Sulfenamide 1.4 1.4

TABLE-US-00004 TABLE 4 Sample No. 4 5 Sample Type.sup.1 Cont Inv Stress-strain ATS (cured 18 minutes at 150° C.; test at 23° C.) Tensile strength (MPa) 17.2 20.7 Elongation at break (%) 496 509 100% modulus (MPa) 1.81 2.09 300% modulus (MPa) 8.44 10.0 Rebound, 23° C. (%) 50 49 Rebound, 100° C. (%) 61 63 Tear strength.sup.2 (cured 25 minutes at 150° C.; test at 23° C.) Original, N 103 99 Aged 14 days at 70° C. in air 68 55 Processing Uncured G′ 183 197 Stiffness G′ @ 10% strain, 90° C., ARES 1328 1438 Hysteresis Tan D @ 90° C., 10% Strain 0.15 0.15 Cord Adhesion (cured 35 minutes at 155° C.; test at 23° C.) Seat Adhesion to PE, N 148 186 Rubber coverage, % 55 70 Hot U Adhesion (ASTM Test No. D2138), N 177 203 Rubber coverage, % 90 85 Fabric Adhesion (ASTM D413), N 6.8 11.4 Rubber coverage, % 75 85 .sup.1Cont = control; inv = inventive .sup.2The hot tear resistance property (tear strength) determination is conducted for peel adhesion of a sample to another sample of the same material. A description may be found in ASTM D4393 except that a sample width of 2.5 cm is used and a clear Mylar plastic film window of a 5 mm width is inserted between the two test samples. It is an interfacial adhesion measurement (pulling force expressed in N/mm units) between two layers of the same tested compound which have been co-cured together with the Mylar film window there between. The purpose of the Mylar film window is to delimit the width of the pealed area.

[0055] While the embodiments described herein have been directed to a rubber composition and a pneumatic tire, the present invention is not so limited. The rubber composition may also be used in various other articles of manufacture, including but not limited to power transmission belts, hoses, tracks, tires, air sleeves, and conveyor belts.

[0056] While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention.