Method of increasing the high-speed performance of a carcass structure in a tyre for vehicle wheels and tyre for vehicle wheels

Abstract

The present invention relates to a method of increasing the high-speed performance of a carcass structure in a tyre for vehicle wheels. The method includes: preparing at least one hybrid yarn (13) and assembling a carcass structure (2) comprising at least one carcass ply (3a, 3b) substantially built on cords (12) comprising the hybrid yarn (13). The hybrid yarn (13) comprises a plurality of filaments (14a, 15a) obtained from a first multi-filament yarn (14) of polyester and a second multi-filament yarn (15) having a decay of the modulus with the temperature lower than 20%. Each of the first multi-filament yarn (14) and second multi-filament yarn (15) comprises a plurality of individual filaments (14a, 15a). The individual filaments (14a) of the first multi-filament yarn (14) are at least partly mixed in proportions of at least 50% with the individual filaments (15a) of said second multi-filament yarn (15).

Description

Technical field [0001] The present invention relates to a method for enhancing the high-speed performance of a carcass structure in a tire for a vehicle wheel and a tire for a vehicle wheel. Background technique [0002] Tyres for vehicle wheels generally include a carcass structure associated with a belt structure. The tread band is applied at a radially outer position of the belt structure. Green tires are constructed by assembling corresponding semi-finished products made of elastomer mixtures and then molded / cured. [0003] Specifically, the present invention relates to a high-performance tire such as, for example, HP (high-performance) tires and UHP (ultra-high-performance) tires or tires used in sports fields such as track racing, or used in various SUVs (sports Multi-function vehicles), the SUVs combine mass and volume that are typical characteristics of wagons with sports car performance), the high-performance tires are used for very powerful cars or motorcycles, or more ...

AI Technical Summary

Problems solved by technology

[0011] The Applicant has found that the above-mentioned heating of the known reinforcing cords belonging to the carcass structure determines a decrease in the modulus of the yarns forming the cords, as a result, relative to the The ideal deformation under the condition of ℃ room temperature), the real deformation of the carcass subjected to acceleration increases

[0012] In addition, the Applicant has found that because man-made fibers are highly hygroscopic, i.e. have a modulus that is very dependent on the moisture content of the fibers, and because during the processing of fibers the drying process is complex and difficult to obtain in an optimal manner (Some amount of moisture is trapped in the fibers anyway), so the modulus of wet rayon yarns incorporated into the tire carcass is less than the modulus given by theory, which leads to an ideal Deformation of the carcass, the real deformation of said carcass is increased

[0013] In addition, it will be more difficult to set the performance of man-made fibers on tires since the mechanical characteristics of man-made fibers depend on the water content in the fibers (which is variable and depends on the efficiency of the drying system)

In addition, water trapped in man-made fibers can cause defects (bubbles, debonding, etc.) in the finished tire

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