Tyre balancing compositions

摘要

Visco-elastic tire balancing compositions comprising 1) 85 to 97% by weight of a glycol ether component comprising one or more ethylene/propylene glycol copolymer ethers of the general formula (I) or the general (II) or mixtures thereof R—O{[CH(CH3)CH2—O—]m[CH2—CH2—O—]n}H (I) R1—(O—{[CH(CH3)CH2—O—]m[CH2—CH2—O—]n}H)2 (II) wherein R is hydrogen or an alkyl group of 2-8 carbon atoms; R1 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 ratio n:m 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) 3 to 15% by weight of a fumed silica gel former; said balancing compositions being visco-elastic 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.

主权项

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(CH3)CH2—O—]m[CH2—CH2—O—]n}H  (I)R1—(O—{[CH(CH3)CH2—O—]m[CH2—CH2—O—]n}H)2  (II)whereinR is hydrogen or an alkyl group of 2-8 carbon atoms;R1 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; andn 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.