Lubricant-containing pellets of thermoplastics processs for preparing same and use thereof

• US 5,763,084 A
• Filed: 10/11/1996
• Issued: 06/09/1998
• Est. Priority Date: 08/31/1993
• Status: Expired due to Term

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Pagilagan, Rolando Umali, Michels, Klaus Josef Maria
• Primary Examiner(s): Le, H. Thi
• Application Number:
  US08/728,738
• Time in Patent Office: 606 Days
• Field of Search: 428/403, 428/407, 427/222, 427/242, 427/384, 427/402, 427/416, 427/417, 427/419.5, 427/419.8, 252/35
• US Class Current: 428/403
• CPC Class Codes: B01J 2/006 Coating of the granules without description of the process or the device by which the granules are obtained to prevent the granules sticking together B01J2/30
• CPC Class Codes: B29B 2009/163 Coating, i.e. applying a layer of liquid or solid material on the granule
• CPC Class Codes: B29B 9/16 Auxiliary treatment of granules
• CPC Class Codes: Y10T 428/2991 Coated
• CPC Class Codes: Y10T 428/2998 including synthetic resin or polymer

Abstract

Lubricant-containing pellets of thermoplastic resins which have a continuous lubricant film firmly adhering to the surface of the pellets are created by a process which mixes and combines uncoated pellets of thermoplastic resins with a metal salt of a fatty acid lubricant at a temperature of from 20° C. to 50° C.

Claims

1. A process for the preparation of lubricant-containing pellets of thermoplastic resins, comprising

(a) uncoated pellets of thermoplastic resins and a lubricant comprised of a metal salt of a fatty acid are combined and mixed at a temperature of from 20°

C. to 50°

C.; and

(b) the resulting pellet-lubricant adducts are then kept in motion so that they are subjected to a sufficient number of mutual impacts and shearing forces causing a firmly adhering, continuous lubricant film to be formed on the pellets.

2. The process according to claim 1 wherein the process is a continuous process and the process step (b) is carried out in a dense phase conveying system.

3. A process according to claim 1, wherein at least one additional lubricant layer is applied to the surface of the firmly adhering, continuous lubricant film.

4. Lubricant-containing pellets of thermoplastic resins obtainable by a process according to any one of claims 1, 2 or 3.

5. Lubricant-containing pellets of thermoplastic resins prepared in accordance with the process of claim 3, said lubricant-containing pellets having a at least two lubricant layers in which

(a) the first lubricant layer is comprised predominately, on a weight basis, of an aluminum salt of a fatty acid and is present on the surface of the pellets in the form of a continuous firmly adhering film;

and

(b) the second lubricant layer comprising a lubricant having a melting point of 140°

C. or less and is present on the surface of the first lubricant layer.