Acid scavengers lactates

Referring to the polyolefin industry, metal stearates (especially calcium, sodium and zinc) and s)mthetic dihydrotalcites are of paramount importance as acid scavengers applied in additive formulations. A minor part is occupied by the calcium lactates/lactylates (salts of lactic acid), ZnO and other oxides. 

Like calcium stearates, calcium lactates are produced by the reaction of Ca(OH)2 with lactic acid and/or stearic acid to form the calcium stear-oyl-2-lactylate, respectively. Besides the conventional acid scavenging performance which is analogous to the stearates, the lactic acid derivatives are able to form chelate complexes with residual amounts of aluminium and titanium via the free OH group present. 

Calcium lactate compounds may form complexes with trace metals, such as titanium or aluminum. In propylene polymer compositions, potassium citrate as an acid scavenger has been proposed (3). In hydrotalcite type acid scavengers, the chloride anions are inter-... 

Another group of organic antacids are represented by metal lactates, especially calcium lactate (Figure 26) and calcium stearoyl-2-lactylate. Besides their action principle as acid scavengers, these derivatives are able to form chelate complexes even with traces of residual aluminum and titanium in polymer matrices. Their addition can help to avoid discoloration of polymer formulations, particularly in combination with phenols. 

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