Remembering the legend Prof Ian Durham Rattee

Excerpt: As tribute to Prof Rattee, his first foreign student, the writer, takes this opportunity to rewrite the plenary lecture delivered by him on 50 Years of Innovation of Reactive Dyes.

Prof Ian D Rattee OBE, Co-Inventor of 'Procion’ Reactive Dyes

Remembering the legend Prof Ian Durham Rattee

Contributed by Dr. K. S. Murthy (Pidilite Industries Ltd)

IN 1953 British chemists Ian Rattee and Dr.William Stephen at I.C.I in London found that when cotton was dyed with dyes containing dichlorotriazinyl groups under mild alkaline conditions, there was no fibre degradation. Thus, a major breakthrough for the dye industry was made when I.C.I introduced their Procion M dyes. Reactive dyes are highly coloured organi c subst ances t hat at t ach themselves by a chemical reaction that forms a covalent bond between the molecule of dye and that of the fibre. The dyestuff thus becomes a part of the fibre and is less likely to be removed by washing than are dyestuffs that adhere by adsorption. This invention revolutionised the colouration of textiles to facilitate the production and industrial use of the bright wash fast colours, 100 years after the discovery of the first commercial synthetic dye by Sir William Henry Perkin, the Father of synthetic dyes and the Founder of the British chemical industry, who discovered the first man-made organic dye (Mauve) in 1856. At the Perkin Centenary in 1956, Ian Ratee and William Stephen were awarded the Gold Medal of the Society of Dyers & Coloursists for the development of the practical system of colouring cellulosic fibres. Henry E Millson award for invention from Association of Textile Chemists & Colorists (AATCC) followed in 2000.

Prof Rattee was born in Sydenham, London on 24 March 1926 and obtained B.Sc. with Honours in Chemistry at the Imperial College of Science & Technology, London in 1945. He was a member of the Royal Society of Chemistry, the Society of Dyers and Colourists (SDC), and the Worshipful Company of Dyers of the City of London. He became a technical officer in the Dyehouse department of I.C.I. Dyestuff Division and until 1950 worked on the level-dyeing properties of acid and chrome dyes on wool and on the relation between these properties and dye constitution. In 1951 he began work on the dyes capable of reacting chemically with fibres, these investigations culminating in the development of the Procion dyes. His achievements also include Perkin Medal in 1975 from the SDC and Freeman of the City of London from the Worshipful Company of Dyers. He was also a Chartered chemist, Associate of the Royal College of Science (A.R.C.S) and a Fellow of the Royal Society (F.R.S.C) of Chemistry.

In 1962 at the age of 36, the University of Leeds appointed Ian Rattee as Professor and Head of the Department of Colour Chemistry & Dyeing till his retirement in 1984. He had published over 35 papers in various journals, obtained 25 patents in the UK, USA and France, relating to reactive dyes and new dyeing processes and coauthored Physical Chemistry of Dye Absorption with M.M.Brever and his work on dyes, printing inks and a new transfer printing process continued for the next 20 years. Professor Rattee visited universities and industrialists in China, India, and Iraq as an advisor on textile coloration at the request of the United Nations and the British Council. His other interests included the theatre. His passion for the performing arts and his acting spanned over 60 years and entertained several audiences. When he was once asked what he would have liked to have been if not a scientist he responded that he would have opted to be a film director. He was fluent in German, Italian, French, Spanish, and Russian.

Prof Rattee will be remembered for his invention that has impacted the lives of everyone who has ever worn clothing coloured with reactive dyes which did not run or fade when washed. When anyone asked what he did for a living, he would simply say that he was a "scientist" and a "teacher". His contribution to both fields was recognised in 1977 in the Queen's Silver Jubilee and Birthday Honours when he was awarded the OBE in recognition of his work in science and teaching. Professor Rattee died on 15 May 2015 in Harrogate District Hospital, North Yorkshire, UK when he was 89 years old. Despite failing health he had maintained an active lifestyle. His son, David Rattee notified the death of his father (Members Remembered Section of the SDC Website). He is survived by his second wife, Dale Cowan, and his two sons, David and Paul from his first marriage (to Pamela) two grandchildren Catherine and Robert and his great grandson Nathan.

In the inaugural lecture at the University of Leeds in 1963, he discussed and illustrated the relation between industrial and academic research drawing a distinction between discovery - the relation of what exists in our environment and the study of the laws that govern it and invention - the utilisation of the results of discovery to change that environment besides problems arising from the difficulties in communication, especially in large industrial complexes and exemplified the role of the universities in the training of graduates for participation in applied scientific activities.

As tribute to Prof Rattee, his first foreign student, the writer, takes this opportunity to rewrite the plenary lecture delivered by him on 50 Years of Innovation of Reactive Dyes in April 2004 at Manchester Conference Centre, UMIST followed by screening of video film (Mr.Ullhas Nimkar) at the SDC India conference in June 2004 at Mumbai. The writer's report then of the latter was published in COLOURAGE, July 2004.

The writer fondly reminisces the years that he spent with Prof Rattee and interaction over the years, particularly the last meeting they had over dinner hosted by Prof Rattee and Dale at Leeds in 2013 and the SDC Award function which he attended especially to see his student receive the silver medal. It was a moment of pride when his mentor acknowledged to him that his first ever PhD thesis was received through this student. While the world will remember Prof Rattee as a great dyestuff chemist and the co-inventor of Procion reactive dyes, to me he will always be more than that - a friend, philosopher and guide!

Procion Story

Ambience in 1950s

Prof Rattee spoke on operations that existed at ICI Blackley in 1950s, creating phases for development and remarked that to some extent pressure on R&D in the industry had diminished by ability to migrate to countries of cheaper labour. He went on to talk about circumstances which surrounded the emergence of reactive dyes. New technological developments depend not only on application of scientific thinking but also on timing, context and some luck and this was so with reactive dyes too. The value of looking back doesn't apply in places of reminiscences but in the lessons which could be learnt in order to find out what might have been discarded and whether what had been achieved now was a satisfactory replacement.

Atmosphere in the Dyehouse

Quoting German philosophy "Man with future is one with longest memory" he said that the conditions that existed in dyestuff industry and ICI, Blackley in 1945 were different when he came up from Imperial College to Dye House Department. The trainees enjoyed the selection and 9 months training program, which introduced them to every aspect of coloration (including plastic, lipstick etc) and had wide contact with all the practices of the industries with which they were concerned. They went into the laboratories where there were graduates from universities and the atmosphere was fruitful and stimulating because at all times the scientist had to convince the practical man who had to face the critical faculties of the scientists. Creativity by and large was self generating and confined almost entirely to dye applications. In his 17 years of working, there was relatively less clarity about what to do or work on except general work. Things were different in the research department where chemist was the master of creation who produced compounds that were tested by subordinates in the laboratory, who reported back and were not expected to learn chemistry. There was no communication between them, the success rate of research products was very low probably 1 in 10,000 samples produced as commercial products and there were no further discussion as to why a particular sample did or did not work.

Physical Chemistry of Dyeing

There was yet another factor concerning dyestuffs import regulations in the 50s and one could not import dyestuffs without license and hence warranted their manufacture indigeneously. So the pressure on research was envisaged and it was here that dyestuff application received importance and developed widely throughout the concerned textile dyestuff chemistry. Manchester Institute of Science & Technology in early 1930s began work on physical chemistry of textile coloration related processes and followed through 1940s. A dyeing research section was set up in the dye house department under the leadership of Thomas Vickerstaff, author of the book on 'Physical Chemistry of Dyeing', which became a rare work. This laboratory rapidly established itself as a highly respected centre of excellence. It gave rise to an atmosphere of intellectuality, creativity and imagination and gave status to the department in the industry and specifically it gave some understanding of colouration as a subdivision of physical chemistry and an understanding of dyeing as a two-phase process in which conditions inside and outside of the paradigm were related and not the same and this act was the basis of the reactive dyes development.

Early phase of reactive dyes for wool

Started in 1951 in the wool section of the dye house run by Chief Colourist, a practical man who was not given to theoretical speculations, but interested in introducing new effects rather than improve the existing dyeing process. He was seeking for direct contribution made to technical application developments and new processes in the hope that some new colorant would be produced. Various attempts were made to introduce novel systems, temporary solubilisation, which have been blocked and ideas of making dyes to wool with formaldehyde cross-link. Of other products, one arose potential interest with unusual properties of dyes containing chloroacetylamino group and dyes containing acetylamino group and the former with improved fastness properties and increased level dyeing properties. Reactions involving the dyes and fibre were studied to produce both stable and unstable bonds which were explained with different levelling properties and fastness. Of the dyes with variable behaviour, one dye acted 100% that needed to study the effect of the bond i.e. environment and structure of the dye on its behaviour and the discussions began with the coinventor Dr.Willie Stephen. This took some time while they worked on direct cotton dyes.

Direct cotton dyes

Quality direct cotton dyes were dominated by those containing bridging groups based on triazine of Ciba. They considered making dyes containing dichloro triazinylamino dyes but could not produce dye powder which decomposes since they were unstable to be isolated and found to be unsuitable for wool dyeing. The dye molecule was first condensed with cyanuric chloride and the product reacted with the NH, SH and OH groups on the wool. However, as the triazine-dye adduct only attach to wool in the presence of alkali, and as wool is more sensitive to NaOH-degradation than cotton, this method did not progress further. At that time in a German textile research show, they came across an article of Southern Research Laboratory, USA to make chemically modified cottons which had innate drip dry crease resistant finish properties and then they had reacted cotton by immersing in a very strong caustic soda followed by cyanuric chloride to produce modified cotton, which was a very efficient process. Dyes were prepared using this process analogies and it was possible to produce them.

Management culture

One of the virtues of efficiency of management at that time was focus on the strategy of doing research on cotton from wool. The reaction was close to Schotten-Baumann reaction (1886) in which condensation of acid chloride with hydroxyl group is promoted by alkali and they started to think about the conditions. The first thing was to get the water out of the way so pad the dye into cotton, dry and wash off alkali to produce an intense wet fast shade and clearly the product which could not be produced earlier was now produced and practically going to be useful. They had to reduce the amount of caustic soda on the consideration of charge distribution of ions in two-phase systems where one of them charges cotton to negative charge. The issue was how to control the situation which was inevitable using dye with alkali saturated salt to fix the dye and this was what worked in 1953. As per literature (Ciba) survey, it was possible to isolate dichloro triazinyl dyestuffs and started using that on the manufacturing scale. They began looking for minimal hydrolysis rate around pH 6.5 in a buffer in the wet paste and tried under minimum hydrolysis conditions and produced the product, which gave results on textiles. Though there was a wise policy at that time not to tell management too much at this stage, they found the product worked and accordingly George White was informed and progress was made with patent filing for printing and dyeing processes. They called the system salt fixed dye because it required alkali and salt to fix. In 1954, they patented a procedure in which cotton was treated with triazine-derived dye using only 3% caustic soda, resulting in a dyed fabric with excellent wet fastness properties. And in 1955 the first commercial reactive dyes were produced.

Application aspects

Bill Marshall and Douglas Weston�s job in cotton section was to adapt this reaction to Pad-Steam continuous dyeing processes, which were then in vogue and they overcame migration of dye during drying and produced results. In printing, apart from thickening emulsions, cellulose based starches and gums showed reaction with the dye and warranted suitable thickenings systems like sodium alginate that has strong negative charge. This involved dyestuff and also reactive centres for reacting fibre with the dyes and could be used as thickening agents for printing process and suitable alternative found how to use, determine and establish. There was yet another problem of print paste (containing dye and alkali) stability when some of it was used immediately and the rest of it a month later. Subsequently, use of sodium bicarbonate developed alkalinity on steaming with satisfactory results. It was observed that print pastes containing bicarbonate on applying to the fibre, the dye was fixed even while drying (steam heated drying cylinders) the prints.

Procion dyes

A star was born in astronomy and hence the new dyes should be called Procion and these were new range for cotton.

Mono chlorotriazinyl dyes

They were produced since print pastes containing Dichloro triazinyl dyes were unstable and hence unsuitable for printing. This led to the development of Mono chlorotriazinyl dyes and much better results were obtained when they worked under severe alkaline conditions and printing processes became interesting. Ciba used cyanuric chloride in making direct cotton dyes and accentuated Intellectual Property Rights (IPR) in that field. Interest of both countries formed an alliance (Ciba-ICI) which gave ICI free entry into mono chlorotriazinyl dyes (Procion H) and Ciba (Cibacron) ranges for application.

Pad-Batch system

For dyes that had insignificant affinity for fibre, they looked for the possibility of developing batch system. And this opened up the market for dyes for continuous dyeing. Finally, development of Pad-Batch system: Pad- Roll system, padding-batching system in which batching the roll in cabinet steaming. Cold Pad-Batch-wash and with that batch washing system and Pad- Batch system continued to grow in importance using Procion, Remazol etc. Factory had to make a system to continuously prepare padding methods containing dye and alkali and it needed a system of mixing - flushing device. Another one is Procion-Resin process for fixation at zero costing, but the resin finishes were uneven.

Development of other reactive systems

On the chemistry side, there was intense activity and hundreds of alternative reactive systems were evaluated by I.C.I and other dye manufacturers of repute and rapidly over 12 years, 50 different distinct ranges of reactive dyes came into existence. Hoechst has been working on Vinyl Sulphone reactive system incorporated in Remalan dyes for wool and Remazol dyes for cotton particularly for discharge printing due to their intrinsically low affinity and substantivity properties. I.C. found the way to develop Phthalocyanine Turquoise Blue. Use of quaternary groups offered tremendous opportunities to control dyeing behaviour. There has been intense active research for fixation levels upwards to 100%.

Conclusion

Patterns got by post cards showed women's clothing containing gorgeous colour prints, which excited fashion at that time. After 1950s, the trends saw cultural transformation in clothing with polyester and cotton and the 60s helped to swing in favour of reactive dyes.

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