additives | Film production


batch from Tosaf optimised for polypropylene (the company already offers grades providing similar properties in polyethylene). The company says it remains highly effective even at very low atmospheric humidity. Even low rates of addition of just 1% to 5% for extrusion bring about a signifi cant reduction of the high electrical surface resistance typical for products made of PP, the company claims. ST7505HP has no effect on the colour and transparency of the material and meets FDA and EU requirements for food contact. In laboratory testing, ST7505HP has demonstrated a


strong antistatic effect which is retained over the long term even at just 12% RH (Figure 6).


Investigating dispersion


BASF’s Irgastat P products are polymeric systems based on polyamide/polyether block amides, which can be used as permanent, non-migratory antistatic agents. They are recommended where a permanent antistatic effect is needed for applications such as electronic and industrial packaging, including fi lms and sheet as well as injection mouldings. This product class is thermally stable and quite effective at low humidity (under 10%). The effect is immediate after incorporation into the host matrix. Surface resistivities of better than of 1012 ohms/


sq can be achieved at concentrations of 15%, and better than 1011


ohm/sq at concentrations of 20%.


“We have examined the effectiveness of Irgastat P18 in LLDPE blown fi lms,” says senior technical manager Rick King. “In parallel, we also examined different methods of introducing the product into the host matrix, and how this might have an impact on surface resistivity


Figure 6: Tosaf’s ST7505HP masterbatch provides a strong and lasting antistatic effect (decay time less than one second) in very dry air at loadings as low as 5% Source: T


osaf


of the resulting compounded products. For example, we looked at pre-compounding the formulations (fully compounded) versus using a 50% concentrate of Irgastat P (as a pre-dispersion) and a “salt and pepper” mix of the neat Irgastat P18 product with the host LLDPE resin on the blown fi lm line.”


King says that of the three different methods of


introduction, the 50% masterbatch technique (pre- dispersion) appeared to provide results that fall more on a straight line over the concentration range exam- ined in the experiments (Figure 7). “As the concentra- tion of Irgastat was increased to 15% (target loading to achieve better than 1012


values for surface resistivity started to coalesce,” he says. It was observed that the outside of the fi lm consistently afforded slightly lower surface resistivity values in comparison to the inside but this was not considered to be statistically signifi cant. Optical properties were better with the pre-compounded and the pre-dispersed masterbatch approach.


“As a result, we are comfortable with all three of the approaches to introduce Irgastat P to the host matrix,” King says.


Click on the links for more information:  www.basf.com


 www.clariant.com  www.ccpmb.com


 www.mariontechnologies.com  www.tosaf.com


Figure 7: Surface resistivity of a blown fi lm grade LLDPE loaded with different levels of BASF’s Irgastat P18 antistatic additive showing the effect of dispersion technique – pre-compounded, concentrate and ‘salt and pepper’ Source: BASF


24 COMPOUNDING WORLD | January 2016


 www.borealisgroup.com  www.sukano.com  www.croda.com  www.ampacet.com  www.akzonobel.com


www.compoundingworld.com


ohm/sq. surface resistivity), the


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84