Continuous dish-washing cleanser granulate prepn. - by hydrating sodium tri:poly:phosphate and granulating with sodium silicate, surfactant and opt. soda

摘要

Cleansing granulate, (A), for dish washing machine use is prepd. continuously by first (i) spraying 20-60 pts. wt. anhydrous Na tri-polyphosphate (I), consisting of 60-100% phase II prod. and having average grain-size 0.05-0.5 mm, in a continuous mixer, within 0.2-5 secs., with sufficient water to form 30-80 (40-80)% hexa-hydrate, while simultaneously working the mixt. mechanically so that 85 (90 wt.% has grain-size 0.2 mm and =2 (=1) wt.% has grain-size 0.1 mm. After 5-60 secs. outside mixer the material is (ii) mixed in a granulation mixer with 25-70 pts. wt. powdered, anhydrous Na silicate having compsn. Na2O : SiO2 = 1 : 0.9 to 1 : 1.5 and opt. with 0-25 pts. wt. anhydrous NaOH and/or Na2CO3 and then sprayed with an aq. soln. of 0.5-5 pts. wt. Na silicate in 2-12 pts. wt. water, opt. with the addn. of a tenside, and granulated by stirring for 60-300 secs. (iii) On leaving the granulation mixer, the material is further moved 5-15 min. in a steam-satd. atmos. and then cooled with air, opt. after adding further cleansing components. The granulate contains, by wt., 20-60% (I) (calculated as the anhydrous salt), 30-80 mol.% of which is present as the hexa-hydrate; 35-75%, calculated as the anhydrous salt, of Na silicate contg. water of hydration, 0-25% anhydrous Na2CO3 and/or NaOH, 0.2-2% low-foaming nonionic surfactant and opt. additives. Prod. agglomeration is prevented. The granulates are dust-free, resist abrasion- and storage, and wash well even under unfavourable conditions.