Patent GB-1479831-A (GB)
Title: Purification of low pressure polyolefins
IPC: C08F6/02
Filed: 1975-01-03
Abstract: 1479831 Purification of polyolefins RUHRCHEMIE AG 3 Jan 1975 [10 Jan 1974] 294/75 Heading C3P A process for purifying a polyolefin which has been produced with the aid of a catalyst system comprising a halogen-containing compound of Periodic Group 4a, 5a or 6a and an organometallic compound of a metal of Group 1a, 2a or 3b and an organic diluent, comprises treating the polyolefin with water, at least a part of which is continuously recirculated via an ion exchanger and returned to the purification zone. In the example (and referring to Fig. 1) low pressure polyethylene which is moist with gasoline, is brought to the boil with water in flask 14. The evaporating water/gasoline mixture is condensed in condenser 17 and separated in vessel 18. The lower water phase flows back into the flask. Via pump 20 and filter 19 a portion of the water is removed and passed through ion-exchanger 21 containing a basic ion exchanger and returns to the flask 14 via a regulating valve 25. In an alternative arrangement (Fig. 2) the polymer may be passed into contact apparatus 1 via pipe 11 where it is contacted with water vapour introduced via lines 7. Some of the water is removed via filter 2 and pump 3 and passes through ion exchanger 4 and returns to apparatus 1. When ion-exchanger 4 is saturated, ion-exchanger 5 can be used whilst the other is regenerated with for example NaOH (in the case of anion exchangers) from vessel 8. Vaporized gasoline is removed via line 17 and the purified polymer via line 16. 1479851 Purifying enzymes MERCK & CO Inc 10 Feb 1975 [15 Feb 1974] 5572/75 Heading C3H [Also in Division B1] Pyrogenic material is removed from an aqueous solution by adjusting its ionic strength to 0À1 to 0À2 molar at pH 6-10 and passing the solution through a column of a basic anionexchange resin, whereby the pyrogens are irreversibly adsorbed and pyrogen-free aqueous solution is displaced from the column. The method finds particular application in the removal of pyrogenic materials from L-asparaginase at pH 7À0-7À5 over a column of diethylaminoethyl dextran gel. 1479856 Binder for foundry mould mixtures STATNI VYZKUMNY USTAV MATERIALU 8 July 1976 17218/75 Headings C3N and C3U A liquid binder for foundry mould and core mixtures comprises an aqueous colloidal solution of at least one alkali metal silicate and finely-divided starch, which mixture has been heated at 70-90‹ C. The silicate may have a SiO 2 /Na 2 O weight ratio of 2À1-2À5: 1, and the mixture preferably includes 70-90% by weight of silicate solution and 10-30% of the starch. The solution and starch may be mixed cold and then heated to 70-90‹ C. for 60-90 minutes. Exemplified compositions are (i) 95À5 parts (volume) quartz sand; 6 parts (vol.) binder (80% by weight sodium silicate solution, 20% starch); 3 parts (vol.) bentonite; 1À5 parts (vol.) Portland cement and 0À5 parts (vol.) NaOH solution; (ii) 92 parts (vol.) quartz sand; 5 parts (vol.) binder (83% by weight sodium silicate solution, 15% starch and 2% carboxymethyl cellulose); 3 parts (vol.) bentonite and 0À3 parts (vol.) NaOH solution.