Vehicle Tire

Abstract

The invention relates to a pneumatic vehicle tire having an inner liner composed of a sulfur-crosslinked rubber mixture containing 80 to 100 phr (parts by weight, based on 100 parts by weight of all rubbers in the mixture) of at least one butyl rubber and/or halogenated butyl rubber, at least one filler, 1 to 60 phr of at least one coumarone-indene resin and 1 to 60 phr of at least one aliphatic hydrocarbon resin, wherein the total mass of coumarone-indene resin and aliphatic hydrocarbon resin does not exceed 65 phr.

Claims

1.-6. (canceled)

7. A pneumatic vehicle tire having an inner liner composed of a sulfur-crosslinked rubber mixture comprising: 80 to 100 phr (parts by weight, based on 100 parts by weight of all rubbers in the mixture) of at least one butyl rubber and/or halogenated butyl rubber; at least one filler; 1 to 60 phr of at least one coumarone-indene resin; and, 1 to 60 phr of at least one aliphatic hydrocarbon resin; wherein the total mass of coumarone-indene resin and aliphatic hydrocarbon resin does not exceed 65 phr.

8. The pneumatic vehicle tire as claimed in claim 7, wherein the sulfur-crosslinked rubber mixture of the inner liner contains 80 to 100 phr of at least one halogenated butyl rubber.

9. The pneumatic vehicle tire as claimed in claim 7, wherein the sulfur-crosslinked rubber mixture of the inner liner contains up to 20 phr of at least one further diene rubber selected from the group consisting of polyisoprene, polybutadiene, styrene-butadiene copolymer and epoxidized natural rubber.

10. The pneumatic vehicle tire as claimed in claim 7, wherein the sulfur-crosslinked rubber mixture of the inner liner contains 5 to 30 phr of at least one coumarone-indene resin.

11. The pneumatic vehicle tire as claimed in claim 7, wherein the sulfur-crosslinked rubber mixture of the inner liner contains 5 to 30 phr of at least one aliphatic hydrocarbon resin.

12. The pneumatic vehicle tire as claimed in claim 7, wherein the sulfur-crosslinked rubber mixture of the inner liner is free of plasticizer oils and processing aids.

Description

[0027] The invention is now to be illustrated in detail with reference to comparative examples and working examples, which are summarized in table 1.

[0028] For all of the mixture examples in the tables, the amounts stated are parts by weight based on 100 parts by weight total rubber (phr). The comparative mixtures are identified by V, and the mixture for the inner liner of the invention by E. The mixtures differ only in the plasticizer oil and resin admixtures. Mixture 1(V) is a rubber mixture for inner liners comprising plasticizer oils. In mixture 2(V), some of the plasticizer oil has been replaced by an aliphatic hydrocarbon resin. Mixture 3(V) contains solely aliphatic hydrocarbon resin, and mixture 4(V) solely coumarone-indene resin. Mixture 5(E) for the pneumatic vehicle tire comprising the inner liner of the invention does not contain any plasticizer oil, but contains the specific combination of coumarone-indene resin with aliphatic hydrocarbon resin.

[0029] The mixture was produced under standard conditions in two stages in a laboratory tangential mixer. The conversion times until attainment of a relative crosslinking level of 10% (t.sub.10) or 40% (t.sub.40) were ascertained by monitoring the vulcanization process using a rotorless vulcameter to DIN 53 529. The Mooney viscosities (ML 1+4) of the mixtures have also been determined to DIN 53 523 with a shearing disk viscometer at 100° C.

[0030] All the mixtures were used to produce test specimens by vulcanization under pressure at 160° C. for 15 minutes, and these test specimens were used to determine material properties typical in the rubber industry. The following test methods were used for the tests on test specimens: [0031] Shore A hardness at room temperature by durometer to DIN ISO 7619-1 [0032] Resilience at 70° C. to DIN 53 512 or ISO 4662 or ASTM D 1054 [0033] Air permeability to DIN 53 536 at air temperature 70° C. without and with aging at 70° C. for 14 days

[0034] Tires of 255/30 R 19 dimensions were also built, the inner liner of which comprised the mixtures of table 1, and these tires were used to conduct the following tests: [0035] Tire service life: Drum test in accordance with the service life test to FMVSS 139 with regard to cracking/fracture resistance of inner liner and sidewall [0036] Rolling resistance: to ISO 28580

[0037] The values ascertained were converted to performance, normalizing the comparative mixture V1 to 100% performance for each tire property tested. The tire properties of the other mixtures then relate to this mixture V1. Values less than 100% here mean a deterioration in the properties, whereas values more than 100% represent an improvement.

TABLE-US-00001 TABLE 1 Constituents Unit 1 (V) 2 (V) 3 (V) 4 (V) 5 (E) Bromobutyl phr 100 100 100 100 100 rubber N 660 carbon phr 55 55 55 55 55 black Plasticizer phr 16 8 — — — oil/processing aid Aliphat. resin.sup.a phr — 12 20 — 12 Coumarone- phr — — — 20 8 indene resin.sup.b Stearic acid phr 2 2 2 2 2 Zinc oxide phr 3 3 3 3 3 Accelerator phr 1.2 1.2 1.2 1.2 1.2 Retardant phr 0.2 0.2 0.2 0.2 0.2 Sulfur phr 0.62 0.62 0.62 0.62 0.62 Properties t.sub.10 min 3.95 3.3 2.2 3.3 2.3 t.sub.40 min 7.5 6 4.3 7.6 4.3 Mooney ML — 69 71 73 61 69 1 + 4 Shore hardness ShA 49 52.8 51.6 42.6 45.9 Resilience % 36.5 32.7 34.8 33.2 34.5 Air permea- m.sup.2/Pa * s 4.3 * 3.1 * 2.8 * 3.7 * 3.3 * bility at 70° C. 10.sup.−17 10.sup.−17 10.sup.−17 10.sup.−17 10.sup.−17 without aging Air permeability m.sup.2/Pa * s 4.4 * 3.5 * 3.0 * 3.9 * 3.3 * at 70° C. after 10.sup.−17 10.sup.−17 10.sup.−17 10.sup.−17 10.sup.−17 aging Tire properties Tire service life % 100 124 103 172 140 Rolling % 100 100.3 99.9 99.7 100.8 resistance .sup.aaliphatic C5 resin with narrow molecular weight distribution, Piccotac ™ 1095, Eastman Chemical Company .sup.bcoumarone-indene resin, Novares ® C 90, Rutgers Chemicals

[0038] It is apparent from table 1 that the specific combination of the two resins in mixture 5(E) can achieve good processing characteristics (indicators are the Mooney viscosity and the low scorch times (t.sub.10/t.sub.40)) coupled with low air permeability. What is particularly surprising is the effect of the combination of the resins on resilience at 70° C., which serves as an indicator of rolling resistance. Low resilience is typically accompanied by low rolling resistance. If the two resins are combined, what is obtained is not a distinct reduction in resilience at 70° C. as expected from the individual measures according to 3(V) and 4(V), but one at the level of 3(V). The tire comprising mixture 5(E) also has high tire service life with regard to the cracking/fracture resistance of inner liner and sidewall and low rolling resistance.

[0039] It is simultaneously advantageous that mixture 5(E) for the inner liner can achieve properties that are at least equally good as those with mixture 1(V), but without any need to use plasticizer oils and processing aids, especially mineral oil plasticizers.