Micro-processing; small scale sampling and testing that makes a big impact

Many of todays leading edge R&D facilities are using micro-processing to create test formulations because of its many advantages. The main benefit of micro-processing over normal large scale processing is much faster formulations development at much lower R&D costs. You use less material (usually 5 ml of base + additive), process samples faster and get more data, more quickly with cheaper equipment and infrastructure. The Xplore™ equipment gives you the choice between 2, 3, 5, 7 and 15 ml, or more.

How micro-processing works

Micro-processing consists of two steps:

  1. Compounding via melt extrusion
  2. Shaping via molding, film casting or fiber spinning and conditioning

Compounding

In the compounding step, a base material is mixed with additives to form a homogeneous mixture. Newly synthesized neat materials (without additives) can also be processed to obtain its nascent material properties. Because only a few grams of material are used in the first step, the compounding step is performed differently than in industrial scale compounders.

The quality of the mixture is controlled by choosing the residence time through a valve rather than by the screw length and geometry, as in conventional machines. The valve’s position determines whether compounded material is re-circulated, further extending the mixing process, or guided to the outlet of the compounder. In addition to batch mode, all our micro-compounders can process materials in continuous mode for film or fiber applications. These micro-compounders are equipped with two conical, fully intermeshing co-rotating screws to ensure maximum dispersion, or two fully intermeshing counter-rotating screws to process shear- or temperatur-e sensitive materials.

Shaping

Compounded material can be further shaped for testing purposes. The most common ways to shape compounded material are extrusion of:

  • Strands. The simplest way of shaping is done by extruding the compounded material via the die. This yields a strand which can be further analyzed using DSC, TEM or SEM or other techniques like dissolution test for pharmaceutical applications.
  • Test samples. Another way of shaping your compounded material is to further process it into a certified test sample using the injection molder. This instrument can be connected directly to our micro compounder – via a preheated transfer cylinder – to obtain standard test bars or any other desired shape, such as pills, rings, cups etc., without changing the thermal history of the material.
  • Cast film. With a slit-die mounted onto the compounder barrel you can produce a cast film. This can vary in thickness from a few hundred microns down to less than 5 microns and a width of 35 - 65 mm. Our dedicated cast film line helps you efficiently produce films from very small amounts of material.
  • Fiber. A mono filament or fiber can be spun from a few grams of material with a fiber spinning unit. The diameter of the die and its draw-ratio determine the diameter of the filament produced. Subsequently you can use the conditioning unit to further elongate the filament via a controlled heating step.