WO1997004970A1

WO1997004970A1 - Method of improving tyre traction

Info

Publication number: WO1997004970A1
Application number: PCT/GB1996/001815
Authority: WO
Inventors: Alistair Robert Parish
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-07-26
Filing date: 1996-07-26
Publication date: 1997-02-13
Anticipated expiration: 1998-01-26
Also published as: AU6622796A

Abstract

A method of improving the grip or traction of a vehicle tyre comprising applying an hydrocarbon based solvent to the surface of the tyre is described. The hydrocarbon based solvent is, typically, a white spirit or mineral spirit usually a petroleum hydrocarbon fraction with boiling point widths of the spirits covering 30 - 70 °C in the range of 100 - 300 °C. A dispenser is also defined.

Description

Method of improving tyre traction

The present invention relates to a method for improving tyre traction and to a substance which when applied to the surface of the tyre improves its traction, particularly, but not exclusively, on snow.

During the winter months a covering of snow on the roads can cause significant problems for vehicles. As the vehicle passes over the snow, the snow becomes compacted and thus tends to melt causing an increase in slippage. The slippage causes the tyre to repeatedly compact the same area of snow and thus causes more snow to melt which results in still further slippage until the vehicle can no longer pass. The problem is more acute in more remote areas where salt treatment has not occurred or on hillsides where greater traction is necessary.

The problem has been addressed by the application of snow grips to the tyres of vehicles. Typically, a snow grip comprises a steel chain which passes around the tyre of the vehicle and, in use, has the effect of biting deeper into the snow layer to provide the necessary improvement in grip. Various snow chains and snow grips are available which provide in varying degrees the improvement in grip which they are designed to produce.

The present invention solves the problem of grip in a different manner.

According to a first aspect of the present invention there is provided a method of improving the grip or traction of a vehicle tyre comprising applying an hydrocarbon based solvent to the surface of the tyre.

According to a second aspect of the present invention there is provided a vehicle tyre treated with an hydrocarbon based solvent. Advantageously, the application of the hydrocarbon based solvent to the surface of the tyre removes the grease and oil which may have come into contact with the surface of the tyre previously. However, the improvement in traction of the tyre surface after application of the solvent produces a surprising improvement in traction on tyres already treated to remove any surface oil or grease, particularly on snow surfaces.

The following is proposed as an explanation for the surprising improvement in traction but the invention is not, in any way, limited by the explanation.

When the solvent is applied to the surface of the tyre it appears to have a tendency to swell into the tyre causing it to soften. The softened rubber consequently has improved traction. However, it is not known why the improvement should be so marked on snow. References to snow in this document should be taken to include all types of snow including all types of ice.

According to a third aspect of the present invention there is provided a solution containing an hydrocarbon based solvent for use in the method of the first aspect of the present invention.

Preferably, the hydrocarbon based solvent is a white spirit or mineral spirit. Typically, the white spirit is a petroleum hydrocarbon fraction with boiling point widths of the spirits covering 30 - 70 °C, most typically about 50°C in the range of boiling points from 100-300°C, most typically 140-250°C. Typically, the hydrocarbon based solvent contains less than 25% aromatics, most preferably about 15%.

According to a fourth aspect of the present invention there is provided a method of driving a vehicle to improve friction comprising the steps of:- a) applying a hydrocarbon based solvent to one or more of the vehicle tyres and b) driving the vehicle over snow.

Preferably, the hydrocarbon based solvent is at ambient temperature prior to application. The method also improves if the tyres are at ambient temperature prior to application.

According to a fifth aspect of the present invention there is provided the use of a tyre treated with a hydrocarbon based solvent for driving over snow.

According to a sixth aspect of the present invention there is provided an aerosol dispenser with a dispensing head displaced from the dispenser and connected thereto by an arm which extends beyond the body of the dispenser. Advantageously, the displacement of the dispensing head away from the dispenser allows the head to be directed at the surface of the tyre underneath the wheelarch of the vehicle so that the jet can be applied directly to the surface of the tyre whilst the user grips the container without undue inconvenience and without having to apply the aerosol at difficult angles.

Embodiments and examples of the invention will now be described, by way of example, and with reference to the accompanying examples and drawings in which:-

Figure 1 shows a schematic diagram of the dispensing head in use in accordance with the third aspect of the present invention, and

Figure 2 shows an enlarged view of the dispensing head and stalk arrangement in accordance with the third aspect of the present invention.

A suitable hydrocarbon based solvent which can be used to put the invention into effect is BSS 254 which is a type of white spirit. The manner in which this is produced is in accordance with techniques and methods which are known in the art.

The solvent has been tested on the tyres of vehicles after they had ground to a halt due to slippage on snow surfaces. The effect of the application of the solvent to the tyre surface is to produce a surprising improvement in traction and, in all cases, resulted in the vehicle proceeding forward easily. This effect is illustrated by the following examples.

Effect of white spirit on the laboratory traction of a passenger car compound

1. Compound

A typical passenger car tyre formulation was mixed and finalised in a laboratory scale Banbury mixer to produce about 1.27kg of compound. The formulation is given below:

Ingredient Amount (pphr)

SBR 80

BR 20

Zinc oxide 5

Stearic acid 2

N234 65

Ennerflex (oil) 15

Santoflex 13 1.5

TMTD 0.2

Sulphur 1.8

CBS 1.2 Rheometry was performed using a Monsanto MDR2000E to determine the optimum cure time at 160°C (please see included trace and table). Compound was moulded at 160°C for 17 minutes to form test sliders for the skid test.

2. Pendulum Skid Test

Skid resistance of the compound was measured using a Pendulum Skid Tester by which the trailing edge of a slider (76.3 ± 0.35mm) was dragged across different surfaces for a standard distance. The recovery of the pendulum on following through was a measure of the friction developed on any surface and a high skid number represents more friction or skid resistance. Each slider was cleaned with alcohol to remove any surface bloom or oil and the alcohol was allowed to evaporate before testing. There was a minimum of ten runs across each surface before an equilibrium skid number was measured.

A different slider was used for each surface. A value for friction, the skid number, was obtained for each surface before exposure to solvent. Testing on ice was performed with sliders at ambient temperature (23°C) and sliders cooled to equilibrium at -20°C for 90 minutes. Sliders were dipped in white spirit (BS245) to a depth of about 2mm before examining the effect of the solvent on friction.

For the room temperature tests only, the excess spirit was drained off before testing. For skid measurement on ice, drying the surface of the slider of all white spirit before testing in order to prevent contamination of the ice track was necessary. Any residual solvent may have evaporated so slowly as to affect later testing.

Hardness measurements were taken to show the effect of swelling by white spirit into the test-pieces. The hardness of the sliders before testing was 74 ± 1 (IRHD) units. Results

3.1 Hardness

As white spirit swells into the test-piece so hardness was reduced ( able 1 ) .

Table 1. Hardness as a function of swelling time

Time, min 0 5 10 30

IRHD, + 2 74 72 71 68

3.2 Wet and Dry Traction

Table 2 shows the results obtained from friction studies performed at ambient temperature under both dry and wet conditions.

Table 2. Wet and dry traction

Surface* Dipping Time Skid No. ** Sample No. (min)

Wet 0 30 1/1 concrete 5 12

Wet wavy 0 9.5 1/2 glass 5 5.5

Dry wavy 0 69 1/3 glass 5 94

The concrete surface is a non-abrasive one and so hardness is the most important property of the rubber that affects friction.

The wavy glass has a texture similar to a non-abrasive asphalt surface. ** After drying at ambient temperature the skid number recovered to within 1 unit of the original reading.

In wet conditions, both on concrete and glass, the white spirit appeared to have a lubricating effect that reduced traction. While on dry glass, traction increased after dipping into white spirit.

3.3 Ice traction

Results of traction measured on ice are given in Table 3 in which the effect of slider temperature and white spirit temperature can also be compared.

Table 3. Traction on Ice (-20°C, ± 1°C)

Sample Slider W. Dipping Slider Skid

No.* Temp. °C Spirit Time Hardness Number

Tem . °C (min) IRHD ± 2

1/4 21 21 0 74 31

21 21 5 - 78

21 21 30 68 75

1/5 -20 -20 0 87 29

-20 -20 5 - 54

-20 -20 30 82 50

1/6 -20 21 0 86 29

>-20 21 5 - 72

>-20 21 30 70 75

Slider 1/4 was kept at ambient temperature and immersed in white spirit at ambient temperature.

Slider 1/5 was taken to -20°C and immersed in cold (-

20°C) white spirit.

Slider 1/6 was taken to -20°C initially and then immersed in white spirit which was at ambient temperature. In all ice traction tests the skid number approximately doubles after dipping in white spirit suggesting much improved traction. It would appear that cold white spirit had less of an effect that white spirit at 23°C.

4. Summary

Application of white spirit to a typical passenger car tyre compound:

■ increased, by a factor of 2, the ice tradition at measured -20°C.

decreased wet traction measured at ambient temperature.

increased dry traction measured at ambient temperature.

Referring to figure 1, an aerosol can 2 has a removable head 4 which is fitted with a permanent extension stalk 6 which extends at right angles to the axis of the canister and is fitted with a spray head 8 at its other end. The spray head 8 is permanently fixed to the extension stalk 6 but is rotatable thereabouts so that the angle can be varied to suit the position of the head with respect to the surface of the tyres. The head 8 is fitted with a wide angle spray aperture 10 which gives maximum coverage of the tyre surface 12.

The method of applying is to pass the head 8 and stalk 6 beneath the wheel arch 14 of the vehicle so that the aperture 10 faces the surface onto which the aerosol is to be applied. The user may then apply the aerosol without undue inconvenience and may twist the head of the aerosol in order to provide the most efficient spray pattern when applying the solvent to the tyre surface. Referring to figure 2, the aerosol canister 16 has a centrally disposed delivery tube 18 which allows the aerosol to pass upwards from the container into the head 20 which is fitted onto the upper part of the delivery tube 18 and has a co-operating L shaped delivery passage 22 which co-operates with the delivery tube 18 when the head is fitted thereon so that the aerosol may pass up through the delivery tube and into the L shaped tube 22 in the head. The L shaped tube 22 exits the head 20 at the side thereof. An extension stalk 24 fits into the same side of the fixed head to co-operate with the L shaped tube 22 so that the aerosol may pass down the extension stalk and into the dispensing head 26 where it passes through a second L shaped delivery passage 28 before delivery to the wide angle aperture 30. The stalk extension is 300mm in length and is fixed permanently to nozzles 20 and 26. The first nozzle 20 may, however, be removed from the canister delivery tube 18 and, if desired, an ordinary nozzle may be fitted thereon to use the aerosol canister in an ordinary manner. This may be used, for example, with vehicles which do not possess wheel arches.

Various modifications to the invention could be carried out without departing from the invention as defined. In particular, it would be possible to devise various solvents which could be used to carry out the invention. The suitable solvents would be known to the skilled person who would carry out routine tests to ascertain which solvents would possess the described properties. Further tests would easily show which solvents proved to have the optimum characteristics.

Claims

1. A method of improving the grip or traction of a vehicle tyre comprising applying an hydrocarbon based solvent to the surface of the tyre.

2. A vehicle tyre treated with an hydrocarbon based solvent.

3. A method of driving a vehicle to improve friction comprising the steps of:-

a) applying a hydrocarbon based solvent to one or more of the vehicle tyres and

b) driving the vehicle over snow.

4. The use of a tyre treated with a hydrocarbon based solvent for driving over snow.

5. A method as claimed in claim 1 or 3, wherein the hydrocarbon based solvent is a white spirit or mineral spirit.

6. A method as claimed in claim 5, wherein the white spirit is a petroleum hydrocarbon fraction.

7. A method as claimed in claim 6, wherein the boiling point widths of the spirits cover 30 - 70 "C in the range of 100-300°C.

8. A method as claimed in claim 6, wherein the boiling point widths of the spirits cover 45 - 55 °C in the range of 100-300°C.

9. A method as claimed in claims 5-8, wherein the hydrocarbon based solvent contains less than 25% aromatics.

10. A method as claimed in any of claims 1, 3 or 5-9, wherein the hydrocarbon based solvent is at ambient temperature prior to application.

11. A method as claimed in any of claims 1, 3 or 5-10, wherein the tyres are at ambient temperature prior to application of the solvent.

12. An aerosol dispenser with a dispensing head displaced from the dispenser and connected thereto by an arm which extends beyond the body of the dispenser.

13. A vehicle tyre as claimed in claim 2, wherein the hydrocarbon based solvent is a white spirit or mineral spirit.

14. A vehicle tyre as claimed in claim 13, wherein the white spirit is a petroleum hydrocarbon fraction.

15. A vehicle tyre as claimed in claim 14, wherein the boiling point widths of the spirits cover 30 - 70 °C in the range of 100-300°C.

16. A vehicle tyre as claimed in claim 14, wherein the boiling point widths of the spirits cover 45 - 55 ^βC in the range of 100-300^βC.

17. A vehicle tyre as claimed in any of claims 13-16, wherein the hydrocarbon based solvent contains less than 25% aromatics.

18. A vehicle tyre as claimed in any of claims 2 or 13-17, wherein the hydrocarbon based solvent is at ambient temperature prior to application.

19. A vehicle tyre as claimed in any of claims 2 or 13-18, wherein the tyres are at ambient temperature prior to application of the solvent.

20. A solution containing an hydrocarbon based solvent for use in the method of any of claims 1, 3 or 5-11.

21. The use of a tyre as claimed in claim 4, wherein the hydrocarbon based solvent is a white spirit or mineral spirit.

22. The use of a tyre as claimed in claim 21, wherein the white spirit is a petroleum hydrocarbon fraction.

23. The use of a tyre as claimed in claim 22, wherein the boiling point widths of the spirits cover 30 - 70 °C in the range of 100-300°C.

24. The use of a tyre as claimed in claim 22, wherein the boiling point widths of the spirits cover 45 - 55 °C in the range of 100-300°C.

25. The use of a tyre as claimed in any of claims 21-24, wherein the hydrocarbon based solvent contains less than 25% aromatics.

26. The use of a tyre as claimed in any of claims 4 or 21-

25, wherein the hydrocarbon based solvent is at ambient temperature prior to application.

27. The use of a tyre as claimed in any of claims 4 or 21-

26, wherein the tyres are at ambient temperature prior to application of the solvent.

28. A method of improving the grip or traction of a vehicle tyre as herinbefore described with reference to the examples.

29. A vehicle tyre treated with an hydrocarbon based solvent as hereinbefore described.

30. The use of a tyre treated with a hydrocarbon based i solvent for driving over snow as hereinbefore described.

31. An aerosol dispenser as hereinbefore described with reference to figures 1 and 2.