Slip agents are chemical substances which are brought into action to specifically change the slip properties of plastics. It must be distinguished between the “internal” slip properties, thus the rheological flow properties of the polymers and the “external” slip properties, which are characterized largely by the term tribology.

The dosage of a slip agent by means of a masterbatch offers manifold benefits compared to the subsequent treatment with externally applied slip agent:

• Time of action is clearly extended because of the slip agent deposit within the polymer.
• Dosage is normally smaller and the distribution uniformly.
• No additional process step for application of the slip agent to the finished part is necessary.

Internal slip agents within the polymer melt
They are acting as dissolved or homogeneously distributed viscosity reducers, which increase the flow properties of the melted polymer. For this reason less friction is created during melt processing, local overheating due to high shear rates is diminished and in some cases processing temperatures could be lowered. Due to the better flow of the polymer the mold filling with injection molding is improved and with extrusion an increase of performance is possible. The mechanical characteristics of the polymers in solid state normally are not influenced by slip agents.

External slip agents at the plastic surface of the finished part
External slip agents are incompatible with the polymer because of their chemical structure. By that they are pushed to the surface of the plastic part during and after processing (migration).
An invisible, thin, but durable lubricant film on the surface influences properties like slip ability (slip effect), reduces friction (unpleasant squeaking is eliminated) or improves the separation from other surfaces. With appropriate combinations of additives and their concentration exact coefficients of friction can be adjusted, in order to achieve the desired torque values of plastic screw caps. With sealing applications, the adhesion could be controlled by the adequate dosage of appropriate slip agents.

Release agents or mold release agents
They diminish the adhesion of plastic melts and hot plastic parts to metal surfaces and therefore reduce the de-molding resistance or the adhesive force between the plastic article and the mold. They build up a separation layer between metal and the polymer matrix, which enables an easier detaching of the molded part. By means of a selective choice of additives, the influence on other material properties of plastics is kept as small as possible.

Typical additives:

• Polyol esters (e.g. glycerol esters with simultaneous antistatic effect)
• Fatty acid amides (e.g. erucamide)
• Waxes (e.g. low molecular weight polyethylene wax)
• Polysiloxanes (silicon compounds with distinct molecular weight)

Take notice of the following:

Slip agents alter the surface properties of polymer parts to a greater or lesser extent. Possible effects of the additives to subsequent process steps like welding, sticking, printing or vanishing of the molded parts – in case of doubt – should be determined in a preliminary test.

With higher dosages, depending on polymer and type of slip agent, an impact on the transparency could take place, this could be diminished by selection of an appropriate additive.

For applications concerning food packaging, high grade, organoleptic neutral slip agent masterbatches are available, which do not exert influence on taste or smell of the packaged food.

Available carrier polymers: PE, PP, PS, PC, PET, PA, UNI-carrier, others if applicable upon request.

Combi Masterbatches e.g. with additive combinations or pigments are available as well.

Standard program/individual adjustments: Beside of our standard program we also develop individual adjustments depending on required specification and quantity.

Food contact: Yes, if applicable with restrictions – please ask for the appropriate documents (product information/food contact approval/declaration of compliance).