Bulk density is a property of powders and granules and other substances. It is defined as the mass of many particles of the material divided by the total volume they occupy. The total volume includes particle volume, inter-particle void volume, and internal pore volume.
Bulk density is very important when using volumetric dosing systems. The same pigment concentrations can have different results if the bulk density is different.
The science of colour measurement.
Tendency of the colour to remain constant over time when applying the same masterbatch dosage under the same conditions throughout the production process.
Measure of the colouring ability of a masterbatch. A degree of the colour intensity given by the masterbatch.
It is the general term for the process of forming covalent bonds or relatively short sequences of chemical bonds to join two polymer chains together.
The cross-linking can be done in different ways in the cable industry. These include Peroxid Crosslinking, Silane Crosslinking and Irradiation Crosslinking.
Dilution is the property according to which a masterbatch is integrated in the polymeric compound. A dilution problem can occur when the Masterbatch does not evenly incorporate into the polymeric compound.
More intense colour or masterbatch lumps may be observed in the final product. This can be solved by modifying the process conditions, raw materials or the masterbatch formulation.
Dispersion is the property according to which a pigment contained in masterbatch is evenly distributed in the polymeric compound. A dispersion problem may have occurred if pigment spots can be seen in the final product.
This can be solved by improving the masterbatch quality.
Dosage o LDR (Let Down Ratio) is the amount of additive/masterbatch that needs to be added into the polymeric compound to reach the active material/colour target. Technicians express this value in several different ways, the most common being % LDR on weight (3% of masterbatch into 97% polymer).
The heat stability of a masterbatch is the temperature where the masterbatch keeps its defined properties (do not confuse with polymer heat stability). This characteristic is defined by polymers, additives and pigments. The most restricted heat stability of those components define the masterbatch heat stability.
The degree at which the colour resists to fade because of light exposure. It is commonly measured by the wool blue scale (minimum 1 to maximum 8). The type of pigments and the total amount of them in the masterbatch defines how resistant the colour will be under light exposure.
A concentrated mixture of dispersed pigments and/or additives encapsulated during a heat process into a carrier, via extrusion or high speed mixing, and presented in a granular form.
UV stabilizers are a class of chemical additives added to polymeric materials to inhibit or retard their degradation produced by the photo-oxidation which is the combined result of light and oxygen.
UV stabilizers usually act by absorbing the UV radiation preferentially, and dissipating the energy as low-level heat.
Different UV stabilizers are utilized depending upon the substrate: benzotriazoles and benzophenones, which work by absorbing the UV radiation and preventing the formation of free radicals, and HALS (Hindered amine light stabilizers) which work to scavenge radicals produced by weathering.
The degree at which the colour resists to fade because of outdoor conditions (light, temperature and humidity). It is commonly measured by the grey scale (minimum 1 to maximum 5). The type of pigments, the total amount of them, and the polymeric compound recipe define how resistant the final product will be under outdoor conditions.
Technicians can experiment by leaving the material outdoors for months or years, or they can use specific equipment to carry out accelerated simulation tests (QUV test or Xenon Lamps) which can reduce the amount of time needed by approximately 10 times.
