Pirelli Coordinamento Pneumatici S.p.a.

Fried Krupp Ag Hoesch-krupp

Pirelli Coordinamento Phenumatici S.p.a.

Marco Nahmias

Christa Joseph

Robert Schrafft

Christoph Carlhoff

Pierluigi De Cancellis

Claus-Jurgen Lorenzen

Martin Jogwich

A vulcanizable rubber composition is described comprising a cross-linkable unsaturated chain polymeric base, wherein is incorporated at least one organic compound, solid at room temperature, selected from the group comprising: amorphous or semicrystalline polymers, oligomers, low-molecular weight organic substances and mixtures thereof, which compound is substantially insoluble in the polymeric base and shows a first or second order transition temperature of from 80 to 160&deg; C. Such rubber composition allows the manufacture of treads with either a low rolling resistance at the temperature of normal use of the tire (40&deg;-70&deg; C.), or a high grip when the tread is subjected to thermal stresses exceeding such temperatures.

Vulcanizable rubber composition for treads of vehicle tires

In a process for producing a vulcanizable rubber composition containing silica and having a low content of carbon black, at least a silica-based reinforcing filler and ad least a silane-based coupling agent are added to and intimately mixed with other ingredients of the composition in subsequent steps, at a temperature of from 165.degree. and 180.degree. C. and between 110.degree. and 160.degree. C. respectively. The rubber composition so obtained has an improved silica dispersion, constant physico-mechanical characteristics and a better drawability and is particularly suitable for the manufacture of treads for tyres with low rolling resistance.

Process for producing a vulcanizable rubber composition with

In a process for producing a vulcanizable rubber composition containing silica and having a low content of carbon black, at least a silica-based reinforcing filler and ad least a silane-based coupling agent are added to and intimately mixed with other ingredients of the composition in subsequent steps, at a temperature of from 165.degree. and 180.degree. C. and between 1100 and 160.degree. C. respectively. The rubber composition so obtained has an improved silica dispersion, constant physico-mechanical characteristics and a better drawability and is particularly suitable for the manufacture of treads for tires with low rolling resistance.

In a process for producing a vulcanizable rubber composition containing silica and having a low content of carbon black, at least a silica-based reinforcing filler and ad least a silane-based coupling agent are added to and intimately mixed with other ingredients of the composition in subsequent steps, at a temperature of from 165.degree. and 180.degree. C. and between 110.degree. and 160.degree. C. respectively. The rubber composition so obtained has an improved silica dispersion, constant physico-mechanical characteristics and a better drawability and is particularly suitable for the manufacture of treads for tires with low rolling resistance.

To determine the carbon black distribution two measurements of spectral intensities of separately produced plasmas are carried out with different time delays relative to a particular laser pulse, the time delay for the second measurement for determining the spectral line intensities of a reference element carbon (I.sub.C') and at least one analysis element (I.sub.A.n') being smaller than for the first measurement; for determining the spectral line intensities of the reference element (I.sub.C) and the other analysis elements (I.sub.A.n). Evaluation of the measurements is performed by reference to calibration information based on reference measurements, which information shows the magnitude of the concentration ratio of the other analysis elements or the at least one analysis element to the reference element (c.sub.A.n /c.sub.C or c.sub.A.n /c.sub.R) as a function of the appurtenant intensity ratio values. By comparison between the intensity ratio values from both measurements with the calibration information, using the concentration of total carbon (c.sub.C) and that of the selected analysis element (c.sub.A.n), the magnitude of the carbon black concentration (c.sub.R) is determined.

Process for tire manufacture with on-line determining of carbon black

To determine the carbon black distribution two measurements of spectral intensities of separately produced plasmas are carried out with different time delays relative to a particular laser pulse, the time delay for the second measurement for determining the spectral line intensities of a reference element carbon (I.sub.C,) and at least one analysis element (I.sub.A.n,) being smaller than for the first measurement; for determining the spectral line intensities of the reference element (I.sub.C) and the other analysis elements (I.sub.A.n). Evaluation of the measurements is performed by reference to calibration information based on reference measurements, which information shows the magnitude of the concentration ratio of the other analysis elements or the at least one analysis element to the reference element (c.sub.A.n /c.sub.C or c.sub.A.n /c.sub.R) as a function of the appurtenant intensity ratio values. By comparison between the intensity ratio values from both measurements with the calibration information, using the concentration of total carbon (c.sub.C) and that of the selected analysis element (c.sub.A.n), the magnitude of the carbon black concentration (c.sub.R) is determined.

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Marco Nahmias