AIRCRAFT TIRE
The present invention relates to an aircraft tire, the tread of which comprises a rubber composition based on at least one first diene elastomer, a reinforcing filler and a crosslinking system, which first diene elastomer comprises ethylene units and diene units comprising a carbon-carbon double bond, which units are distributed randomly within the first diene elastomer, the ethylene units representing at least 50 mol % of the combined monomer units of the first diene elastomer. Such a tire exhibits a performance on landing which is greatly improved, in particular with regard to the wear resistance at very high speeds.
1 . An aircraft tire, the tread of which comprises a rubber composition based on at least one first diene elastomer, a reinforcing filler and a crosslinking system, which first diene elastomer comprises ethylene units and diene units comprising a carbon-carbon double bond, which units are distributed randomly within the first diene elastomer, the ethylene units representing at least 50 mol % of the combined monomer units of the first diene elastomer.
2 . A tire according to claim 1 , in which the first diene elastomer comprises the following units UA, UB, UC and UD randomly distributed within the first diene elastomer,
UA) —CH 2 —CH 2 — according to a molar percentage of m %
UB) according to a molar percentage of n %
UC)
according to a molar percentage of o %
UD)
according to a molar percentage of p %
R 1 and R 2 , which are identical or different, denoting a hydrogen atom, a methyl radical or a phenyl radical which is unsubstituted or substituted in the ortho, meta or para position by a methyl radical
m≧50
0<o+p≦25
n+o>0
m, n, o and p being numbers ranging from 0 to 100
the respective molar percentages of m, n, o and p being calculated on the basis of the sum of m+n+o+p, which is equal to 100.
3 . A tire according to claim 2 , in which the first diene elastomer contains units UE randomly distributed within the first diene elastomer,
UE)
according to a molar percentage of q %
o+p+q≧10
q≧0
the respective molar percentages of m, n, o, p and q being calculated on the basis of the sum of m+n+o+p+q, which is equal to 100.
4 . A tire according to claim 2 , in which the first diene elastomer contains units UF randomly distributed within the first diene elastomer,
UF)
according to a molar percentage of r %
R 3 denoting an alkyl radical having from 1 to 4 carbon atoms or an aryl radical
0≦r≦25
the respective molar percentages of m, n, o, p, q and r being calculated on the basis of the sum of m+n+o+p+q+r, which is equal to 100.
5 . A tire according to claim 4 , in which r is equal to 0.
6 . A tire according to claim 2 , in which at least one of the two molar percentages p and q is different from 0.
7 . A tire according to claim 2 , in which p is strictly greater than 0.
8 . A tire according to claim 2 , in which the first diene elastomer exhibits at least one of the following criteria:
m≧65
n+o+p+q≧15
10≧p+q≧2
1≧n/(o+p+q)
when q is non-zero, 20≧p/q≧1
9 . A tire according to claim 3 , in which the first diene elastomer contains, as monomer units, only the units UA, UB, UC, UD and UE according to their respective molar percentages m, n, o, p and q.
10 . A tire according to claim 2 , in which the first diene elastomer contains, as monomer units, only the units UA, UB, UC and UD according to their respective molar percentages m, n, o and p.
11 . A tire according to claim 1 , in which R 1 and R 2 are identical and denote a hydrogen atom.
12 . A tire according to claim 1 , in which the rubber composition comprises a second elastomer.
13 . A tire according to claim 12 , in which the second elastomer is a highly unsaturated diene elastomer selected from the group consisting of polybutadienes, polyisoprenes, butadiene copolymers, isoprene copolymers and the mixtures of these elastomers.
14 . A tire according to claim 12 , in which the second elastomer is a ternary copolymer obtained by copolymerization of ethylene and of an α-olefin having from 3 to 6 carbon atoms with a non-conjugated diene monomer having from 6 to 12 carbon atoms.
15 . A tire according to claim 1 , in which the first diene elastomer is the only elastomer of the rubber composition.
16 . A tire according to claim 1 , in which the reinforcing filler comprises a carbon black.
17 . A tire according to claim 16 , in which the reinforcing filler is formed to 100% by weight of a carbon black.
18 . A tire according to claim 1 , in which the reinforcing filler comprises an inorganic filler.
19 . A tire according to claim 1 , in which the content of reinforcing filler is from 20 to 70 phr.
20 . A tire according to claim 1 , in which the rubber composition contains from 0 to 20 phr of a liquid plasticizer.
21 . A tire according to claim 20 , in which the content of liquid plasticizer is equal to 0.