Tyre balancing compositions

Abstract

The invention relates to tyre balancing compositions having improved balancing properties comprise a visco-plastic gel and solid bodies having an average smallest dimension in the range of 0.5-5 mm; preferably 1-4 mm, more preferably around 3 mm. When applied in a layer to the inside of a motor vehicle tyre, the compositions act by allowing the solid bodies move through the gel and to concentrate in areas to counteract imbalances. The solid bodies preferably have an average ratio α between their smallest and their largest dimension of α≦2, more preferably α≦1.5, especially around 1. The visco-plastic gel preferably has a storage modulus (G′) between 1000 Pa and 25000 Pa at 22° C., a loss modulus (G″) smaller than the storage modulus, and a critical yield stress above 3 Pa at 22° C. The bodies may be shaped as prolate or oblate ellipsoids, cylinders, rectangular paralleipipeds, or spheres, or mixtures of such bodies; they may have an apparent specific gravity in the range of 500-3000 kg/m 3 , preferably 600-2000 kg/m 3 , in particular 700-1000 kg/m 3 , especially 800-900 kg/m 3 ; they may be made from polyolefins, polystyrene, polyvinyl chloride, polyamide, rubber or glass. The weight ratio between the solid bodies and the gel is from 10:1 to 1:10, preferably from 5:1 to 1:5, in particular from 2:1 to 3:1, such as from 1:1 to 1:2. The invention further concerns a tyre balancing kit and a method for balancing automobile wheel assemblies.

1 . A tyre balancing composition, which comprises a visco-plastic gel and solid bodies having an average smallest dimension in the range of 0.5-5 mm, wherein the visco-plastic gel has a storage modulus (G′) between 1000 Pa and 25000 Pa at 22° C., a loss modulus (G″) smaller than the storage modulus, and a critical yield stress above 3 Pa at 22° C.  
     
     
         2 . A tyre balancing composition according to  claim 1 , wherein the solid bodies have an average ratio between their smallest and their largest dimension of α≦2.  
     
     
         3 . A tyre balancing composition according to  claim 2 , wherein α≦1.5.  
     
     
         4 . A tyre balancing composition according to  claim 3 , wherein α is around 1.  
     
     
         5 . A tyre balancing composition according to  claim 1 , wherein the average smallest dimension of the solid bodies is in the range of 1-4 mm.  
     
     
         6 . A tyre balancing composition according to  claim 5 , wherein the average smallest dimension of the solid bodies is around 3 mm.  
     
     
         7 . A tyre balancing composition according to  claim 1 , wherein the storage modulus (G′) is around 9000 Pa at 22° C., and the critical yield stress is around 30 Pa at 22° C.  
     
     
         8 . A tyre balancing composition according to  claim 1 , wherein the solid bodies are shaped as prolate or oblate ellipsoids, cylinders, rectangular paralleipipeds, or spheres, or mixtures of such bodies.  
     
     
         9 . A tyre balancing composition according to  claim 1 , wherein the apparent specific gravity of the solid bodies is in the range of 500-3000 kg/m 3 .  
     
     
         10 . A tyre balancing composition according to  claim 9 , wherein the apparent specific gravity of the solid bodies is in the range of 600-2000 kg/m 3 .  
     
     
         11 . A tyre balancing composition according to  claim 10 , wherein the apparent specific gravity of the solid bodies is in the range of 700-1000 kg/m 3 .  
     
     
         12 . A tyre balancing composition according to  claim 11 , wherein the apparent specific gravity of the solid bodies is in the range of 800-900 kg/m 3 .  
     
     
         13 . A tyre balancing composition according to  claim 1 , wherein the solid bodies are made from a material selected from the group consisting of polyolefins, polystyrene, polyvinyl chloride, polyamide, rubber and glass.  
     
     
         14 . A tyre balancing composition according to  claim 1 , wherein the weight ratio between the solid bodies and the gel is from 10:1 to 1:10.  
     
     
         15 . A tyre balancing composition according to  claim 14 , wherein the weight ratio between the solid bodies and the gel is from 5:1 to 1:5.  
     
     
         16 . A tyre balancing composition according to  claim 15 , wherein the weight ratio between the solid bodies and the gel is from 2:1 to 1:3.  
     
     
         17 . A tyre balancing composition according to  claim 16 , wherein the weight ratio between the solid bodies and the gel is from 1:1 to 1:2.  
     
     
         18 . A tyre balancing composition according to  claim 1  contained within the air cavity of a motor vehicle tyre.  
     
     
         19 . A tyre balancing composition according to  claim 2 , wherein the average smallest dimension of the solid bodies is in the range of 14 mm.  
     
     
         20 . A tyre balancing composition kit comprising 
 i) a first container containing a visco-plastic gel, wherein the visco-plastic gel has a storage modulus (G′) between 1000 Pa and 25000 Pa at 22° C., a loss modulus (G″) smaller than the storage modulus, and a critical yield stress above 3 Pa at 22° C., and    ii) a second container containing solid bodies having their average smallest dimension in the range of 0.5-5 mm.    
     
     
         21 . A tyre balancing composition kit according to  claim 20 , wherein the visco-plastic gel has a storage modulus (G′) around 9000 Pa at 22° C., and a critical yield stress around 30 Pa at 22° C.  
     
     
         22 . A tyre balancing composition kit according to  claim 20 , wherein the solid bodies have an average ratio between their smallest and their largest dimension of α≦2.  
     
     
         23 . A tyre balancing composition kit according to  claim 22 , wherein α≦1.5.  
     
     
         24 . A tyre balancing composition kit according to  claim 23 , wherein α is around 1.  
     
     
         25 . A tyre balancing composition kit according to  claim 20 , wherein the average smallest dimension of the solid bodies is in the range of 14 mm.  
     
     
         26 . A tyre balancing composition kit according to  claim 25 , wherein the average smallest dimension of the solid bodies is around 3 mm.  
     
     
         27 . A tyre balancing composition kit according to  claim 20 , wherein the solid bodies are shaped as prolate or oblate ellipsoids, cylinders, rectangular paralleipipeds, or spheres, or mixtures of such bodies.  
     
     
         28 . A tyre balancing composition kit according to  claim 20 , wherein the apparent specific gravity of the solid bodies is in the range of 500-3000 kg/m 3 .  
     
     
         29 . A tyre balancing composition kit according to  claim 28 , wherein the apparent specific gravity of the solid bodies is in the range of 600-2000 kg/m 3 .  
     
     
         30 . A tyre balancing composition kit according to  claim 29 , wherein the apparent specific gravity of the solid bodies is in the range of 700-1000 kg/m 3 .  
     
     
         31 . A tyre balancing composition kit according to  claim 30 , wherein the apparent specific gravity of the solid bodies is in the range of 800-900 kg/m 3 .  
     
     
         32 . A tyre balancing composition kit according to  claim 20 , wherein the solid bodies are made from a material selected from the group consisting of polyolefins, polystyrene, polyvinyl chloride, polyamide, rubber and glass.  
     
     
         33 . A tyre balancing composition kit according to  claim 20 , wherein the weight ratio between the amount of visco-plastic gel in the first container and the amount of solid bodies in the second container is from 10:1 to 1:10.  
     
     
         34 . A tyre balancing composition kit according to  claim 33 , wherein the weight ratio between the amount of visco-plastic gel in the first container and the amount of solid bodies in the second container is from 5:1 to 1:5.  
     
     
         35 . A tyre balancing composition kit according to  claim 34 , wherein the weight ratio between the amount of visco-plastic gel in the first container and the amount of solid bodies in the second container is from 2:1 to 1:3.  
     
     
         36 . A tyre balancing composition kit according to  claim 35 , wherein the weight ratio between the amount of visco-plastic gel in the first container and the amount of solid bodies in the second container is from 1:1 to 1:2.  
     
     
         37 . A method for balancing a motor vehicle wheel assembly comprising applying a tyre balancing composition according to  claim 1  to the inner surface of the tyre, mounting the tyre on a tyre rim to form a wheel assembly, and 
 mounting the wheel assembly on a motor vehicle and driving the vehicle for a distance sufficient to allow the balancing composition to balance the wheel assembly, or    mounting the wheel assembly in a device that allows the wheel assembly to be rotated under load conditions similar to those experienced during actual road driving and at a speed where resonance occurs in the wheel assembly, and rotating the wheel for a time sufficient to allow the balancing composition to reduce vibrations to a stable minimum.    
     
     
         38 . A method for balancing a motor vehicle wheel assembly comprising applying the components of a kit according to  claim 20  to the inner surface of the tyre, mounting the tyre on a tyre rim to form a wheel assembly, and 
 mounting the wheel assembly on a motor vehicle and driving the vehicle for a distance sufficient to allow the balancing composition to balance the wheel assembly, or    mounting the wheel assembly in a device that allows the wheel assembly to be rotated under load conditions similar to those experienced during actual road driving and at a speed where resonance occurs in the wheel assembly, and rotating the wheel for a time sufficient to allow the balancing composition to reduce vibrations to a stable minimum.