WINTER TYRE

Most polybutadiene is used in tyre applications, and the majority of this use is in blends with other polymers, such as NR and SBR, where polybutadiene reduces heat build-up and improves the abrasion resistance of the blend. The friction on ice of winter tyres is also improved by using higher levels of polybutadiene in the tread blend. 

Tyres and related products Pneumatic tyre manufacturing dominates the rubber industry in terms of the quantity of raw rubber consumption. About 50-60% of the rubber produced in the world is used for manufacturing tyres and related items. Tyre products include pneumatic tyres and tubes, sohd tyres, t)n e flaps, retread material, and puncture repair Wts (PRKs). NR is the ideal base material for tyres for aircraft, racing cars, heavy duty vehicles such as trucks and buses, off the road vehicles, and tractors. An oil extended form of natural rubber could be used as base material for the manufacture of winter tyres [61]. 

In 1898 the first rubber factory based on the natural product, Suomen Gummitehdas Oy (later Oy Nokia Ab rubber factory), was set up to produce galoshes, i.e. overshoes. The firm specialized in rubber footwear and flourished. In 1926 it began to manufacture tyres for bicycles, and in 1934 tyres for cars. Two years later it introduced its own innovation, winter tyres for cars. The growth of the rubber industry was outstanding. In 1913, it employed over 90 employees and in 1938 as many as 2,570, or 82 per cent of the total workforce of the main chemical industry and 42 per cent of its output, as shown in table 1. Before the Winter War of 1939-40, rubber manufacturing was one of the three biggest chemistry-related branches of Finnish industry. ... 

Fosser, S. 1996. Studded or non-studded winter tyres No significant difference in risk of accidents. Nordic Road and Transport Research, 1, 16. 

Sigthorsson, H. 1998. Studded winter tyres and traffic safety. Nordic Road and Transport Research, 10(3), 4—7. 

Gustafsson M, Blomqvist G, Gudmundsson A, Dahl A, Swietlicki E, Bohgard M, Lindbom J, Ljungman A (2008) Properties and toxicological effects of particles from the interaction between tyres, road pavement and winter traction material. Sci Total Environ 393 (2-3) 226-240... 

The second theory—winter-diffusion—would seem applicable to the particular case of the adhesion of like surfaces (known also as auto-adhesion ). Certainly it occurs in the welding of plastics, and in instances such as tyre manufacture when unvulcanized rubbers adhere spontaneously. On the other hand, it is unlikely that much inter-diffusion takes place when materials dissimilar chemically are brought together. It is well-known that many plastics are incompatible and if mixed will, over a period of time, tend to separate— forming eventually discrete layers. Behaviour of this kind is precisely the reverse of inter-diffusion. 

In countries where studded tyres are used or permitted in the winter, the resistance to wear by abrasion from studded tyres test also needs to be conducted. 

The test to determine resistance to wear of aggregate by abrasion from studded tyres test was developed in Finland, Norway and Sweden. In these countries, studded tyres are permitted and used during the winter period. 

This requirement is exclusively used by some northern European countries that impose the use of studded tyres during winter months. 

---