Patent GB-697657-A (GB)
Title: Improvements relating to the processing of highly polymeric linear polyester materials
Inventor: SHAW WILLIAM
IPC: D06M11/55
Filed: 1950-06-14
Abstract: The affinity for dyestuffs of highly polymeric linear polyesters containing at least one aromatic nucleus in each recurrent structural unit, e.g. polyethylene terephthalate, is improved by alternate treatment with hydrochloric, sulphuric or nitric acid or a mixture of two or more of these acids, and with ammonia.  The treatment may be repeated as required with rinsing between each treatment or each step of the treatment.  Preferred strengths for the acids and proportions in the mixtures are specified.  The ammonia and hydrochloric acid may be aqueous or gaseous.  The temperature of treatment may be from -10 DEG  to 40 DEG  C. and the time from 1 to 10 minutes for the acid and from a few seconds to 10 minutes for ammonia.  In examples: polyethylene terephthalate fabrics are (1) treated in 27 per cent ammonia for 10 minutes at 20 DEG  C., then in 36 per cent hydrochloric acid for 10 minutes at 40 DEG  C., rinsed and dyed in Duranol Brilliant Blue G200 to give a shade four times deeper than obtainable with untreated material; a similar result is obtained using six treatments with 0.1 per cent ammonia and 36 per cent hydrochloric acid; (2) treated with nitric acid and ammonia and dyed as in (1); (3) treated successively with a mixture of sulphuric and nitric acids and ammonia and dyed in Dispersol Fast Scarlet BS; (4) treated with a 27 per cent ammonia solution and a mixture of nitric and hydrochloric acid and dyed as in (1); (5) treated successively with ammonia and a mixture of hydrochloric and sulphuric acids and dyed as in (1).  Specifications 683,218 and 683,634 are referred to.ALSO:The affinity for dyestuffs of highly polymeric linear polyesters containing at least one aromatic nucleus in each recurrent structural unit, e.g. polyethylene terephthalate, is improved by alternate treatment with hydrochloric, sulphuric or nitric acid or a mixture of two or more of these acids, and with ammonia.  The treatment may be repeated as required with rinsing between each treatment or each step of the treatment.  Preferred strengths for the acids and proportions in the mixtures are specified.  The ammonia and hydrochloric acid may be aqueous or gaseous.  The temperature of the treatment may be from -10 DEG  to 40 DEG  C. and the time from 1 to 10 minutes for the acid and from a few seconds to 10 minutes for ammonia.  In examples polyethylene terephthalate fabrics are (1) treated in 27 per cent ammonia for 10 minutes at 20 DEG  C. then in 36 per cent hydrochloric acid for 10 minutes at 40 DEG  C., rinsed and dyed in Duranol Brilliant Blue G200 to give a shade four times deeper than obtainable with untreated material; a similar result is obtained using six treatments with 0.1 per cent ammonia and 36 per cent hydrochloric acid; (2) treated with nitric acid and ammonia and dyed as in (1); (3) treated with a mixture of sulphuric and nitric acids and ammonia and dyed in Dispersol Fast Scarlet B5; (4) treated with a 27 per cent ammonia solution and a mixture of nitric and hydrochloric acid and dyed as in (1); (5) treated successively with ammonia and a mixture of hydrochloric and sulphuric acids and dyed as in (1). Specifications 683,218 and 683,634 are referred to.