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FREQUENTLY ASKED QUESTIONS (FAQ)

Q: - How does SIDISTAR® work in foamed PVC?
A: - SIDISTAR® can replace over 50% of the high molecular weight processing aid in foamed PVC - it is dispersible down to primary particles and each one offers a potential site for cell nucleation - this in turn produces a fine cell formation.

 

Q: - Will my density increase when SIDISTAR® replaces high molecular weight processing aid?
A: - No, as long as gelation is correct the density will be equal or sometimes even lower with SIDISTAR®. 

Q: - How is rheology influenced by SIDISTAR®?
A: - The rheology of the compound depends on the formulation (internal and external lubricants, K-value of the PVC resin, extrusion temperatures, etc.). Therefore only general remarks can be made. SIDISTAR® is almost neutral for gelation, however acrylic processing aids speed up fusion - so when the processing aid is lowered and SIDISTAR® is added in it's place, it may be necessary to fine tune gelation by reducing slightly some of the lubricant.  Usually this is not necessary for up to 50% replacement.

 

Q: - Would one need to use high molecular weight processing aid together with SIDISTAR®?
A: - Yes it is necessary since the processing aid also stabilises the cell structure and adds elasticity to the melt. 

 

Q: - Will SIDISTAR® be added at the same concentration as organic processing aids ?
A: - Usually the replacement has been on a 1:1 basis, however some customers have in fact replaced a higher addition of processing aid by a lower addition of SIDISTAR® with no loss in properties and equal density - therefore saving even more money !

Q: - Is SIDISTAR® suitable for injection moulding or extrusion?
A: - SIDISTAR® can be used for both injection moulding and extrusion compounds.

Q: - How does SIDISTAR® influence HDT (Heat Distortion Temperature)?
A: - In contrast to organic materials, SIDISTAR will increase heat distortion temperature (or at least, not reduce HDT), depending on its concentration.

Q: - Will it be possible to use the same mixing and extrusion parameters with the SIDISTAR® - containing compound as before?
A: - The use of SIDISTAR® replacing same amounts of processing aids does not influence the dry-blend mixing process, therefore the same settings can be used. For optimum dispersion SIDISTAR® should be added to the blend before the filler.
SIDISTAR® can improve processability during extrusion. This advantage can lead to higher output when the machine parameters are optimised.

 

Q: - Does SIDISTAR® effect weathering behaviour ?
A: - SIDISTAR® was extensively evaluated in all PVC stabilised systems [Tin, Lead, CaZn and Organic] for weathering behaviour - there were no issues in any system.

 

Q: - How will an addition of SIDISTAR® affect flame retardancy of PVC?
A: - SIDISTAR® will improve the flame retardancy compared to organic substances.

Q: - Will SIDISTAR® be abrasive on my extruder and other equipment?
A: - No, abrasion tests have shown that a compound filled with SIDISTAR® is less abrasive than a compound filled with the same amount of calcium carbonate.   See Technical Bulletin 10

Q: - Are there any catalytic reactions to be expected?
A: - SIDISTAR® is chemically amorphous silicon dioxide. It is not catalytically active.

Q: - Does SIDISTAR® contain heavy metals?
A: - Due to the metallurgical process in which SIDISTAR® is synthesised, it contains traces of other elements including metals.

Q: - Will SIDISTAR® increase the risk of corrosion?
A: - There is no additional or higher risk of corrosion encountered with the use of SIDISTAR®. 

Q: - Will SIDISTAR® have a negative influence on the recyclability of the PVC products?
A: - No, the improved flow of the melt when using SIDISTAR® will make recycling easier.

Q: - Where do I go for order information?
A: - orders@sidistar.com