Tyre balancing compositions

1. A gel composition suitable for balancing tires consisting essentially of:

1) a glycol ether component comprising a mixture of ethylene/propylene glycol copolymer ethers of the general formula (I) and the general formula (II):

R—O{[CH(CH 3 )CH 2 —O—] m [CH 2 —CH 2 —O—] n }H  (I)

R 1 —(O—{[CH(CH 3 )CH 2 —O—] m [CH 2 —CH 2 —O—] n }H) 2   (II)

wherein

R is hydrogen or an alkyl group of 2-8 carbon atoms;

R 1 is an alkylene moiety of 2-8 carbon atoms in which the two substituents are not carried on the same carbon atom;

m is the mole percentage of propylene glycol in the ethylene/propylene glycol copolymer moiety or moieties; and

n is the mole percentage of ethylene glycol in the ethylene/propylene glycol copolymer moiety or moieties, wherein the n:m ratio is in the range from 35:65 to 80:20;

each glycol copolymer compound having a number average molecular weight in the range of 2000-10000; and

2) a fumed silica gel former;

said gel composition being visco-elastic and having a Storage Modulus (G′) between 1500 Pa and 5000 Pa at 22° C., a Loss Modulus (G″) smaller than the Storage Modulus up to a Cross Over Frequency of 10-40 Hz, and a Critical Yield Stress exceeding 2 Pa,

wherein

the ethylene/propylene glycol copolymer ether of the general formula (I) has a n:m ratio in the range from 40:60 to 60:40 and

the ethylene/propylene glycol copolymer ether of the general formula (II) having a n:m ratio from 70:30 to 80:20 is present in the composition (a) in an amount of 1% by weight of the gel composition and the fumed silica gel former is present in an amount in the range from 6 to 6.7% by weight or (b) in an amount of 2% by weight and the fumed silica gel former is present in an amount in the range from 5 to 6.5% by weight.

2. The gel composition according to claim 1 , wherein the number average molecular weight of the glycol ether component(s) is/are in the range of 3000-10000.

3. The gel composition according to claim 1 , wherein the fumed silica gel former is a hydrophilic type fumed silica having a BET surface area in the range from 200 to 300 m 2 /g; or the fumed silica gel former is a hydrophobized type fumed silica having a BET surface area in the range from 250 to 350 m 2 /g; or mixtures of such hydrophilic and hydrophobized type fumed silica gel formers.

4. The gel composition according to claim 1 , wherein the glycol ether component(s) exhibit(s) a Viscosity Grade determined according to ISO3448 in the range from 800 to 1200.

5. A method for balancing tires having an air cavity comprising introducing a gel formulation according to claim 1 into the air cavity of a tire.

6. The method according to claim 5 , wherein the tire comprises an inner lining and the air cavity comprises at least one foam strip attached to the inner lining.

7. A method for improving the centrifugal stability of tire balancing gel formulations comprising using a composition according to claim 1 for balancing a tire.