Graphene nanotubes for non-marking solid tires: compliance with electrostatic requirements and maintained mechanical properties

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The accumulation of static electricity in non-marking tires can lead to an injury to the operator, fire, and damage to the object.

That is why industrial areas are very strictly regulated by ATEX regulations and by the EN 1755 standard, with the latter being specifically related to industrial trucks (including their tires) when working in potentially explosive atmospheres to prevent the electrostatic discharges.

According to these standards, this type of product must be anti-static or conductive.

ATEX 2014/34/EUEN 1755:2015ISO 3691-1:2011
Equipment and protective systems intended for use in potentially explosive atmospheresSafety of industrial trucks. Operation in potentially explosive atmospheres. Use in flammable gas, vapor, mist and dust Industrial trucks. Safety requirements and verification

New electrostatic requirements

EN 1755:2015

Mandatory: November 2017

  • Static now considered an ignition risk during ‘normal’ operations
  • More detailed assessment of non-electrical components now required

    Electrical properties:

    • Surface resistance of 109

      Industries affected:

      • Chemical
      • Pharmaceutical
      • Food & Drink
      • Waste
      • Cosmetics
      • Military
      • Manufacturing
      • Logistics and other

      TUBALL™ graphene nanotubes improve the physical and mechanical properties of rubbers, contribute to the required anti-static properties without carbon release, and fully comply with ATEX and EN requirements for ESD protection.

      TUBALL™ nanotubes are applied via an easy-to-use additive, TUBALL™ MATRIX, which is a line concentrates based on polymer and plasticizer carriers and pre-dispersed TUBALL™ graphene nanotubes.

      TUBALL™ MATRIX FOR SOLID TIRES

      PROPERTY

      MATRIX 618 beta

      MATRIX 620 beta

      Compatible formulations  

      NR- or NR/BR-based formulations containing mineral fillers

      Concentrate carrier

      Synthetic ester plasticizer

      Polymer in oil-based plasticizer

      TUBALL™ GNT content, wt.%

      10%

      5%

      Processing

      More sensitive*

      Not sensitive

      Dosage required for anti-static properties (105–107 Ω)

      3 wt.% (0.3% TUBALL™)

      4.4 wt.% (0.22% TUBALL™)

      Mechanical properties

      Improved**

      Not affected

      Electrical resistivity

      Stable

      Stable

      * for the last stage on a 2-roll mill      ** the exact values depend on the formulation

      TUBALL™ graphene nanotubes: good performance on all key parameters

      In contrast to other conductive agents, TUBALL™ graphene nanotubes are a versatile conductive agent offering good performance on all key parameters.

      Test results: mechanical properties

      Volume resistivity

      Surface resistivity

      SIMCO ST-4

      EN 60079

      3 wt.% TUBALL™ MATRIX 618 beta

      3.5 × 102 Ω·cm

      5 × 105 Ω/sq

      1.6 × 105 Ω

      4.4 wt.% TUBALL™ MATRIX 620 beta

      4.2 × 102 Ω·cm

      5.2 × 105 Ω/sq

      9.5 × 104 Ω




      KEY BENEFIT 1: ANTI-STATIC PROPERTIES WITHOUT CARBON RELEASE, FOR NON-MARKING COLORED COMPOUNDS

      RESULTS FOR A MOLDED TIRE CONTAINING 4.4% TUBALL™ MATRIX 620 beta

      When using carbon black, owing to its high concentration (10% or more) and because of the spherical shape of the particles, a phenomenon known in the industry as “carbon release” takes place, when the conductive additive is present on the surface of the sample.

      In contrast, graphene nanotubes, owing to their much greater length-to-diameter ratio, are not released to the surface.


      Marking and non-marking conductive rubbers: How to avoid mistakes


      In situations where it is necessary to use non-marking tires, it has been impossible to add any carbon-based fillers – only alternative compositions with a high mineral content have been suitable. Therefore, anti-static plasticizer has very often been used for this purpose in the industry.

      Conductive plasticizer is a humidity-dependent material, so it is not stable during use.

      To achieve anti-static properties, a high dosage of conductive plasticizer is required. However, this has a negative effect on the physical and mechanical properties, especially the mechanical modulus and tensile stretching. In addition, the plasticizer has a propensity to migrate to the surface during storage and use.

      Degradation of mechanical properties and migration of the additive to the surface negatively affect the performance and the shelf life of the product.

      KEY BENEFIT 2: IMPROVED OR MAINTAINED MECHANICAL PROPERTIES

      SOLID TIRES: IMPACT ON THE MOST COMMONLY USED ANTI-STATIC PLASTICIZER AND TUBALL™


      KEY BENEFIT 3: STANDARD PROCESSING AND MIXING EQUIPMENT

      The optimal mixing option is a combination of an internal mixer and a 2-roll mill.


      OTHER BENEFITS

      • Maintained elasticity and mechanical properties
      • Extra-low dosage of TUBALL™ MATRIX that preserve properties
      • Retain colors
      • Permanent and uniform electrical conductivity

      Please, pay close attention to processing guidelines for TUBALL™ MATRIX 618 & 620 beta for non-marking anti-static compounds


      Download PDF version:
      PROCESSING GUIDELINES for TUBALL™ MATRIX 618 beta, 620 beta
      pdf
      1.21 MB

      Application case

      Non-marking solid tires
      click to view case
      Non-marking solid tires

      Additional resources:

      Electrical resistivity guideline: measurement, standards & troubleshooting

      Graphene nanotubes for elastomers: conductivity & mechanical performance (Kate Gorbunova, OCSiAl)


      Graphene Nanotubes Enable Creation of Non-Marking Anti-Static Tires


      Graphene key to non-marking anti-static tires



      Contact us to discuss your project specifications or to request a TUBALL™ MATRIX sample

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