GB317513A - Preservative package for articles in general especially fruits and the like, and the method of making and applying the same - Google Patents

Abstract

317,513. Jackson, L. Mellersh-, (Cellacote Co., Inc.). May 15, 1928. Packing food, tobacco, cigars, drugs, &c.- Unwrapped articles, more especially fruit, vegetables, &c., are enclosed for protection and preservation by applying directly thereto a coating of liquid hydrated cellulose which is then coagulated and dried, causing it to shrink on the article and form a homogeneous covering completely enclosing the article and exerting a compressive force thereon. The articles treated include tobacco, cigars, drugs, eggs and meat. The coating material may be prepared by immersing dried sulphite pulp sheets for about two hours in a bath containing about 17.6 per cent by weight of caustic soda, and at a temperature of about 20‹ C. The sheets are next pressed to remove surplus solution, and ground to flaky form, a preservative, for example 4 per cent of white resin and 6 per cent of sodium tetraborate, being incorporated therewith during the grinding. The material is next stored at about 18‹ C. for from about 63 to 96 hours to allow the reaction between the cellulose, soda and preservative to be completed. It is then treated with carbon, bisulphide in rotary drum or churn for 2-3¢ hours. The material is removed to a mixing kettle having a rotary beater to which a 3-6 per cent solution of caustic soda is added, together with a solution of sodium sulphite which will cause rapid coagulation of the material after application to the articles to be coated. The material is next filtered, for example in a press having linen, cotton, flannel or other suitable filtering medium, the product which is of syrupy consistency being then applied to the article. After coating, the article is immersed for 8-10 minutes in a coagulating bath consisting of a natural salt solution, for example an 11 per cent solution of ammonium sulphate. The coagulation is completed and impurities are removed by immersion in a suitable acid solution, for example a 0.15-0.25 per cent solution of sulphuric acid. The article is then dipped in a weak solution of caustic soda of about 0.05 per cent strength to neutralize the acid, and is then washed and dried. The article may be coated by dipping or spraying or by rolling it on a cloth saturated with the cellulose solution.