- Email: [email protected]
Smithers Rapra's Prague Conference: Nanotechnology, Coloured & Effect Pigments
FOCUS ON P
I
G
A MONTHLY REPORT FROM REG ADAMS FEBRUARY 2016
PLANTS
5-6
Omsk TG will open new carbon black plant in Belarus by August 2016 Plastiblends poised to start-up its third Indian masterbatch plant & now plans to build a fourth GCR expands Spanish capacity Americhem will step up UK plastic colorants capacity by 40-50% Precision Color Compounds expands in Indiana (US)
COMPANIES
6-7
BCD to sell Cabot's fumed silica & carbon blacks in Switzerland Dowd & Guild to sell Chromaflo dispersions & colorants Imerys completes purchase of BASF's hydrous kaolin business ET Horn appointed as distributor for Applied Minerals, CCA & EPS Lansco will sell Shepherd's complex inorganic coloured pigments Pagliara to sell for Silberline in Italy
PIGMENTS
N
T
S
AN INTERNATIONAL NEWSLETTER MONITORING TECHNICAL AND COMMERCIAL DEVELOPMENTS IN THE PIGMENTS SECTOR ISSN 0969–6210
4-5
Average Chinese rutile TiO2 price raised to Rmb 10.15 (equivalent to $1562 per tonne)
EVENTS
E
SMITHERS RAPRA'S PRAGUE CONFERENCE: NANOTECHNOLOGY, COLOURED & EFFECT PIGMENTS
IN THIS ISSUE
MARKETS
M
8
PIGMENTS
The co-located Pigment & Colour Science Forum and TiO2 World Summit hosted by SmithersRapra has been one of the highlights of Autumn in the Northern Hemisphere in recent years and the event is now on an annual cycle, whereas previously these conferences tended to be biennial separate affairs. In October 2014, Montreal was the venue for the co-located twin conferences. In October 2015, the venue was Prague. Already, preparations are well underway for this year's event, to be held in Cleveland, Ohio. Presentations from the first plenary session of the Prague event were reviewed in 'Focus on Pigments', Dec 2015. Presentations from the TiO2 sessions were reviewed in 'Focus on Pigments', Jan 2016. Dr Trevor Sayer (of Expertas) gave the opening paper in the Colour Science Forum, discussing scientific approaches to understanding the psychology of colour preference. He referred to the concept of "valence'', defined as the degree of attraction or aversion that an individual feels towards a specific colour or object. He went on to explain ecological valence theory, which can encompass a number of relevant factors – universal, cultural, subcultural, idiosyncratic and even dynamic variance. Dr Sayer reviewed the changing trends in popularity of the various colours for new passenger cars, noting a shift away from blues and greens over the past 15 years, while red remains the most popular chromatic colour. He concluded by saying that in future colour design tools will be based on
holistic spatial depictions of colour, linked with scientific colour measurement systems. True colour representations can be linked with psychophysical parameters and sophisticated digital apps will emerge, as marketing tools and technical aids for both the colour technologist and the ultimate consumer. Ms Nathalie Roy (an independent colour consultant, based in Montreal) discussed the essentials of product colour validation, with particular reference to the colour/materials/ finishes (CMF) user-centred design process. She also mentioned the importance of sustainability in the field of materials, highlighting the potential for perovskite-structured solar cells (with high efficiencies and low production costs), for lithium sulfur graphene batteries (supplying power for electric cars) and for light emitting diodes (LEDs) embedded into road surfacing materials so as to supplement or even replace conventional lighting on streets and highways. Dr Jiri Filip (of the UTIA Institute, under the aegis of the Czech Academy of Sciences) spoke about the measurement and visualisation of the appearance of materials, highlighting the use of a gonioreflectometer developed by UTIA. For many applications in the interior design of buildings, in medical diagnoses, in the clothing and footwear sectors and in presenting cultural heritage exhibits, it would be useful to have portable devices capable of rapidly providing reliable measurements of appearance, whether
PIGMENTS
PIGMENTS
PIGMENTS
PIGMENTS
FOCUS based on bidirectional reflectance distribution function (BRDF) or bidirectional texture function (BTF) analysis. Ms Judith Van Vliet (of Clariant) presented a paper titled: "Latest colour design forecasting trends'' and this was followed by a discussion of the factors driving change in the colour pigment industry, co-presented by Mr Bill Eibon (of PPG Industries) and Mr Paul Czornij (of BASF). The afternoon ended with a round-table discussion on colour harmony in automotive applications, with contributions from Dr Trevor Sayer, Mr Mark Nichols (of Ford Motor Co), Ms Barbara Sika (of Porsche) and Mr Aappo Roos (of Gasmet Ansyco). The Friday morning session began with a presentation by Dr WernerRudolf Cramer (an independent consultant, based in Münster, Germany) covering interference pigments and especially holographic pigments, with colour shift between 358 and 658 aspecular. Ms Lisa Clapp (of Sun Chemical) gave an excellent overview of pigmentation theory and colour perception. She said: "For nearly 100 years, scientists have attempted to calculate colour in order to articulate differences. A number of separate algorithms have developed and evolved in attempts to more closely match visual perception.'' These include: the Tristimulus (red-greenblue) approach (1931); Wyszecki's CIEUVW model (1964); and the CIE La-b model (1976); FMCII (1971); CMC (1986); CIE94 (1995) and CIEDE2000 (2001). Colour is a function of absorption and reflectance. Pigments absorb light, with the position and shape of the absorption bands defining the colour; the non-absorbed, mainly reflected, light provides the actual light that provides the ultimate colour. Transparency and colour are directly related to pigment particle size due to scattering components. Mie scattering (rather than classic Rayleigh scattering) dominates in pigments, because the size of the scattering particles is comparable to the wavelength of incident light. Wider particle size distributions broaden the scatter and lower the chroma. The presence of aggregates also lowers the chroma and that is why dispersion of the pigment is so important. Sun Chemical pioneered fractal analysis to determine dispersion characteristics. The entire system – pigment, polymer and substrate – must be considered for transparency. Metameric
2
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colours have the same tristimulus values for a reference illumination, but a different spectral response. Under different illuminations, the relative shades of the colours change. Thus, there may be a "colour match'' between two different inks in natural sunlight, but nothing like a match under fluorescent or halide lighting. When haze or "milkiness'' occurs if the reflectance or transmission angle is altered, the key factors are normally film formation and surface texture. Whereas scatter is wavelengthdependent aspecular reflectance, haze is wavelength-independent aspecular reflectance. Gloss has a high wavelength-independent specular reflectance, whereas bronzing is exhibited as a wavelength-dependent specular reflectance. In her concluding remarks, Ms Clapp said: "Colour appearance is very subjective and is not easily related to measured perception, which is very difficult to fully describe with algorithms. Returning to the fundamentals of light absorption and light scattering will give the most accurate description. A close study of the wavelength-dependent reflectance spectrum should identify opportunities for colour matching.'' Colour is complicated! Ms Alice Chadwick discussed the human perception of gloss. Historically, it was believed that it should be possible to define gloss with a single objective measurement. That was the principle underlying the Ingersoll glarimeter (1922), for example. But it is clear that in fact multiple factors are involved, notably the direction of illumination, specular highlights, the surface texture, shape, lightness and colour, the viewing distance and binocularity disparity. So what is going on when we perceive gloss? Ms Chadwick said: "It seems that the visual system is using a constellation of cues and pseudocues in making perceptual judgements. The more cues that are available, the better our perception.'' Schlenk (one of the leading global suppliers of metallic pigments) has published a lot of experimental data with the aim of shedding more light on this topic. Dr Thomas Sowade (of Heubach) provided a useful update on the paper he presented at the Nuremberg Conference earlier in the year. (See 'Focus on Pigments', Jul 2015, 2-3). He began by stating that the world's consumption of lead chromate and molybdate pigments has dropped from 120,000 tonnes in 1980 to about 50,000 tonnes in 2010, with no
obvious sign of the downward trend being arrested. He then discussed the five Heubach alternatives to chrome yellow and moly red. Firstly, Heucodur mixed metal oxides with a rutile structure. Secondly, Vanadur bismuth vanadate pigments. Thirdly, Monolite organic red and yellow pigments. Fourthly, Heucofit LR pigment preparations consisting of a blend of organic and inorganic pigments. Fifthly, Heubach's Tico range of so called "hybrid pigments'', manufactured by a proprietary co-finishing process that effectively attaches organic colorants to a titanium yellow carrier pigment. Prof Mas Subramanian (of Oregon State University) is famous for heading the team which discovered the first new blue chromaphore in more than 200 years – the OSU Blue, based on trivalent manganese in trigonal bipyramidal configurations, with yttrium and indium oxides. In his presentation at the Prague Conference, he spoke about the role of serendipity (luck) in making important scientific breakthroughs. This applied not only to OSU Blue, but also to penicillin, Bakelite, saccharin, X-rays, rubber vulcanisation, Vaseline petroleum jelly, Viagra and Perkins's mauve dye. But he reminded the audience of Louis Pasteur's dictum "Luck only favours the prepared mind.'' Prof Subramanian also discussed the principal causes of colour in inorganic solid materials interatomic excitations (d-d shell electron transitions), charge-transfer excitations, valence to conduction band transitions and intra-band excitations. Crystal chemistry plays an important role. It is interesting to note that rubies are red and emeralds are green simply because of trivalent chromium impurities in aluminium oxide and in beryllium aluminium silicate respectively. Prof Subramanian also posed the question: "Why is it so hard to find stable non-toxic inorganic red pigments that could replace cadmium and mercury pigments?'' This segued into the final paper of the Colour Science session, delivered by Dr Andrew Smith (of Shepherd Color), titled: "Pigment design for function and the future.'' He outlined the many different inorganic pigment chemistries and the many different technical and socio-political factors affecting pigment design. He also discussed the spaces beyond the visible spectrum with opportunities for infrared reflecting black and blue pigments and for ultraviolet absorbing pigments. Shepherd Color has February 2016
FOCUS commercialised pigments based on OSU Blue and the complex highperformance inorganic pigments, RTZ Orange (based on rutile TiO2, tin and zinc) and NTP Yellow (based on niobium-tin pyrochlore). Dr Smith also described his company's Starlight coloured effect pigments and Dynamix stir-in pigments. He ended his talk with a quote by Marcel Proust: "The real voyage of discovery consists not in seeking new landscapes but in having new eyes.'' Meanwhile, over in the parallel TiO2 session on the Friday morning, Mr Stefan Rämisch (of WL Gore & Associates) described the use of filter media at the oxidation and milling/ micronisation stages of sulfate-route and chloride-route TiO2 pigment manufacturing processes. Gore now offers membrane filters made of extended polytetrafluoroethylene (ePTFE) as a clearly more efficient alternative to conventional felt fabric filters. He cited a case study of a TiO2 manufacturer who for many years had been satisfied with the use of acidresistant aramid felt filter bags in the dryer baghouses of the plant, but then found that they were inadequate when the production line was switched to making TiO2 pigments grades with smaller particles and increased flowability. After only four months in service, the TiO2 particles were migrating through the stitch-holes. Replacement of the old filter bags with membrane filters made of ePTFE, at the same time as covering the stitchholes with special seam tape, quadrupled the service-life to 16 months. For the final plenary session of the conference, the audiences from the TiO2 session and the Colour Science session coalesced. Ms Joanne Watson (of Walgreens Boots Alliance) discussed her company's application of colour measurement in the cosmetics sector, specifically in the development of the proprietary No7 Match Made customer service for lipsticks, foundations, blushers and concealers. The first step is to carefully define the customer's skintone on a proprietary scale, on the basis of which the most suitable cosmetic type and colour shade can be identified. In essence, this is similar to the approach outlined by Dr Felix Schmollgrüber (of X-Rite) in a paper delivered at the Berlin Conference four years ago (See 'Focus on Pigments', Jan 2012, 2). Dr Fiona Watson (of Henan Billions) discussed the usage of TiO2 in printing February 2016
ON
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inks, the most important TiO2 pigments in this field being the RDI-S product (developed by Kemira in Finland in the 1980s) and the TR-52 product (an upgraded version of the Comet-300 product launched by Tioxide in the mid-1990s). Sulfate rutile grades are by far the most popular products in the inks segment. Chloride rutile grades are generally considered to be too abrasive, while the hiding power of anatase grades is not considered to be sufficient for many applications. In order to gain EU anti-trust approval for the acquisition of Rockwood's TiO2 assets, Huntsman was obliged to promise to divest part of its ink-grade TiO2 pigment portfolio. Effective 1 December 2014, Henan Billions acquired the TR-52 business from the Huntsman group, entailing the transfer of contracts and customer lists, but not entailing the transfer of any manufacturing assets. Huntsman has continued to make the TR-52 grade at the white-end of its Calais (France) sulfate-route TiO2 plant under a four-year toll-manufacturing agreement. Huntsman (with RDI-S) and Henan Billions (with TR-52) are now competitors in the printing inks customer segment. The technology transfer aspects of the deal have proceeded smoothly. It is naturally in Huntsman's interest that TR-52 (as sold by Henan Billions) is qualified for use by all major customers. Dr Watson noted that global consumption of TiO2 for printing inks now accounts for just over 200,000 tonnes/y of TiO2, of which 90-95% is for packaging inks. The rest is mainly accounted for by white inks in the publications sector. Asia/Pacific accounts for 48% of the TiO2 consumed in printing inks; Europe for 26%; North America for 13.5% and the rest of the world for 12.5%. The global packaging industry is huge, being currently worth more than $950 bn. The consumption of packaging inks, by type of packaging, breaks down as: 56% flexible; 18% cartons; 14% metal (cans, etc.); 7% corrugated board; and 5% rigid plastic. Flexible packaging is destined to be the fastest growing sector in the medium-term future, with cartons also showing rapid growth. Increased demands for packaging functionality dictates a requirement for speciality inks for microwavable packaging, stand-up pouches, aseptic packaging and packaging with good barrier properties. Labels for pouches and shrink-film packaging are often reverse/reverse laminated, which necessitates particular TiO2 properties.
There is also a definite trend towards printing on highly glossy surfaces for strong visual appeal. Printing inks are most commonly solvent-based. In fact, water-based inks currently account for only about 10-20% of total world inks production. UV-curable inks currently account for around 10% of total output, but this sector is destined for rapid growth in the future. The global printing ink industry is much less fragmented than the paint industry. In fact, the top five inkmakers – DIC/Sun Chemical. Flint, Toyo Ink, Sakata and Siegwerk – account for about 60-70% of global ink production. Further small-scale mergers are likely to lead to further industry consolidation in the mediumterm. There are no obvious signs of the emergence of any major Chinese printing inks manufacturer. At present, the Chinese printing ink industry is relatively small and quite fragmented. Clearly, Henan Billions is determined to boost its share of the printing inks segment of the TiO2 market in the future. The final paper at the Prague Conference – on the topic of TiO2 consumption in the plastics industry – was delivered by Mr Rémy Jury (of Profialis). About 1.5 M tonnes/y of TiO2 is currently consumed in the plastics industry. Polyvinyl chloride (PVC), in both rigid and flexible forms (uPVC and sPVC) accounts for about 17% of total world plastics consumption. Polyethylene accounts for 34%, polypropylene for 20%, polystyrene for 9%, polyurethane for 5%, polyethylene terephthalate (PET) for 5% and a variety of other polymers for the remaining 13%. Shin-Etsu is the world's leading PVC producer (with a capacity of around 3.5 M tonnes/y), followed by: Formosa Plastics (3.2 M tonnes/y), Solvay (2.5 M tonnes/y); LG Chem (2.5 M tonnes/y); ChemChina (2.1 M tonnes/y); Ineos (1.75 M tonnes/y) and Oxyvinyls (1.75 M tonnes/y). Smaller suppliers include: Tianjin Bohai, China National Salt Group (CNSG), Shanghai Chloralkali Chemical (SCAC), Axiall, KemOne, Vinnolit and Westlake. The construction industry accounts for about 56% of global PVC consumption. Profialis (owned by the Open Gate Group, a private equity fund) is one of the top five producers of rigid polyvinyl chloride (uPVC) window and door profiles/frames in France. Like many other TiO2 consumers, during the 2011/12 price surge, Profialis took steps to minimise its TiO2
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FOCUS consumption. In 2000, the typical formulation of a white uPVC window profile comprised: 75% base polymer, 10% TiO2, 5% CaCO3 and 10% other additives. By 2010, the typical formulation had changed to: 75% base polymer, 3% TiO2, 12% CaCO3 and 10% other additives. Thus, unit consumption of TiO2 was reduced by about 70%. Mr Jury acknowledged that 3% seems to be the lowest acceptable level of TiO2 for a suitable uPVC product in outdoors applications. He also pointed out that white is no longer quite as dominant as it used to be. In 2005, only 3% of the uPVC profiles sold on the French market were coloured, whereas the proportion had climbed to 25% by 2015. Another method employed for thrifting on TiO2 usage is to move to a co-extruded product, where only the external layer of uPVC incorporates TiO2 to provide weatherability, while the internal layer contains no TiO2. Nevertheless, the volume growth of PVC worldwide is so strong that despite sharp reductions in unit loadings in a variety of applications in construction, packaging, transport, wire and cable sheathings and consumer products, the overall consumption of TiO2 in PVC products is likely to increase. Besides the themes of conventional TiO2 pigments, effect pigments, colour pigments and the quantification of aspects related to colour and gloss perception, the theme of nanotechnology featured strongly in the Prague Conference. This was emphasised from the outset, when Dr Pavel Belobradek (Deputy Prime Minister of the Czech Republic) noted, in his opening address, that the country is already well established as a global centre of excellence for nanotechnology, with more than 30 flourishing companies specialising in this field. Nanoparticulate TiO2 has a wide range of applications in catalysis, in photovoltaic cells, in effect pigments and in ultraviolet absorbers, with plenty of scope for development. Dr Jiri Kus (of the Czech Nanotechnology Industries Association) spoke about the current EU regulatory framework, as it affects nanomaterials. As in the past, the advent of new technologies – mechanised knitting machines and weaving looms, aircraft, radios, microwave ovens and industrial robots – can be handicapped by an outbreak of mass media hysteria. The nanomaterials industry needs to combat "scare stories'' by presenting convincing experimental evidence of benefits and
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advertising popular examples, such as providing drinking water for astronauts, hypoallergenic fabrics and furnishings, storage devices for renewable energy and nano 3-D printers for making human organ replacements. Dr Jan Buk (of Pardam) spoke about his company's business, making nanofibres for a variety of applications. Pardam's product portfolio includes NnF Ceram, made from anatase TiO2, which can be used in air/fuel ratio controllers in vehicle engines, humidity and gas sensors, solid oxide fuel cells, and anti-pollution catalysts. Dr Jiri Bezdicek (originally trained in the Czech Republic and now working at Levenger, Spain) highlighted the use of nanoparticulate TiO2 for water treatment applications. Levenger's FNAQUA (based on nanoparticulate TiO2) can remove pathogenic bacteria, organochlorides and all non-metallic priority organic pollutants from waste water at an operating cost of less than €1.50 per kilolitres and with no adverse environmental effects, unlike conventional hyper-chlorination methods. Prof Josef Krysa (of the University of Chemistry & Technology, UCT Prague) explained the theoretical principles behind nanoparticulate TiO2's properties as a photocatalyst, especially for removing nitrogen oxides, acetaldehyde and general organic debris (dirt). He also showed examples of its use in self-cleaning paints, glass, ceramics and concrete. Finally, he spoke about the use of RZ ink as an indicator of photocatalytic activity developed by UCT Prague in collaboration with Queens' University, Belfast under the EU's Intec programme. A pen filled with RZ ink can be easily used to test the effectiveness of samples of selfcleaning ceramic tiles and other products. Dr Jan Prochazka (of Advanced Materials JTJ) gave a very comprehensive review of applications for nanoparticulate TiO2 in environmental remediation, citing figures for the estimated market potential for annual nano TiO2 sales revenue in the Czech Republic alone as: $3 M for self-cleaning building facades, $0.7 M for historical monuments preservation; and $1.5 M for graffiti removal. He also discussed applications for nano TiO2 in water decontamination, especially in areas containing dioxins and other organochlorine pollutants, public health protection and odour removal.
At the end of the first day of the conference, over 120 delegates enjoyed an evening cruise in a boat on the River Vltava, with a meal, wine and schnapps, all generously funded by Dr Prochazka's company – a subtle indication that the profit margins achieved by this nano TiO2 producer are currently very much healthier than those of the conventional pigment producers! For those who were unable to attend the event, the full set of published papers from the Prague Pigment & Colour Science Forum & TiO2 World Summit conferences (8-9 October 2015) is available for sale. For details, please contact: Ms Sharon Garrington, SmithersRapra, Shawbury, Shrewsbury, Shropshire, SY4 4NR, England. Tel: +44-(0)1939-250383. E-mail: sgarrington@ smithers.com
MARKETS Average Chinese rutile TiO2 price raised to Rmb 10.15 per kilo ($1562 per tonne) China's TiO2 pigment production fell last year for the first time since 2008. According to preliminary data issued by the China National Chemical Industry Productivity Centre (CNCIPC), production for full-year 2015 was 2.323 M tonnes, indicating a 4.5% fall on the 2014 figure. Meanwhile, despite the closure of more than a dozen small and medium-sized plants during the 2012-2015 period, there was still a wide margin of overcapacity in the Chinese TiO2 industry, of the order of 30-40%. Towards the end of last year, several producers reduced their operating rates in order to avoid a build-up of inventories and with a view to trying to stem the steady downward drift in prices. By the end of December 2015, the average domestic price for rutile-type pigment had dropped to Rmb 9.75 per kilo (equivalent to $1500 per tonne). At that level, virtually all producers were failing to cover their cash costs of production. Effective 6 January 2016, Sichuan Lomon (the largest Chinese producer, with a capacity of around 300,000 tonnes/y) declared that it was raising its TiO2 pigment prices by Rmb 0.30 per kilo (equivalent to $46 per tonne). Most of the other leading suppliers – CNNC HuaYuan, Henan Billions, Bluestar and others – followed suit. Encouraged by this success, Sichuan Lomon posted a second price increase of Rmb 0.30 per kilo on 26 February 2016
I
G
A MONTHLY REPORT FROM REG ADAMS FEBRUARY 2016
PLANTS
5-6
Omsk TG will open new carbon black plant in Belarus by August 2016 Plastiblends poised to start-up its third Indian masterbatch plant & now plans to build a fourth GCR expands Spanish capacity Americhem will step up UK plastic colorants capacity by 40-50% Precision Color Compounds expands in Indiana (US)
COMPANIES
6-7
BCD to sell Cabot's fumed silica & carbon blacks in Switzerland Dowd & Guild to sell Chromaflo dispersions & colorants Imerys completes purchase of BASF's hydrous kaolin business ET Horn appointed as distributor for Applied Minerals, CCA & EPS Lansco will sell Shepherd's complex inorganic coloured pigments Pagliara to sell for Silberline in Italy
PIGMENTS
N
T
S
AN INTERNATIONAL NEWSLETTER MONITORING TECHNICAL AND COMMERCIAL DEVELOPMENTS IN THE PIGMENTS SECTOR ISSN 0969–6210
4-5
Average Chinese rutile TiO2 price raised to Rmb 10.15 (equivalent to $1562 per tonne)
EVENTS
E
SMITHERS RAPRA'S PRAGUE CONFERENCE: NANOTECHNOLOGY, COLOURED & EFFECT PIGMENTS
IN THIS ISSUE
MARKETS
M
8
PIGMENTS
The co-located Pigment & Colour Science Forum and TiO2 World Summit hosted by SmithersRapra has been one of the highlights of Autumn in the Northern Hemisphere in recent years and the event is now on an annual cycle, whereas previously these conferences tended to be biennial separate affairs. In October 2014, Montreal was the venue for the co-located twin conferences. In October 2015, the venue was Prague. Already, preparations are well underway for this year's event, to be held in Cleveland, Ohio. Presentations from the first plenary session of the Prague event were reviewed in 'Focus on Pigments', Dec 2015. Presentations from the TiO2 sessions were reviewed in 'Focus on Pigments', Jan 2016. Dr Trevor Sayer (of Expertas) gave the opening paper in the Colour Science Forum, discussing scientific approaches to understanding the psychology of colour preference. He referred to the concept of "valence'', defined as the degree of attraction or aversion that an individual feels towards a specific colour or object. He went on to explain ecological valence theory, which can encompass a number of relevant factors – universal, cultural, subcultural, idiosyncratic and even dynamic variance. Dr Sayer reviewed the changing trends in popularity of the various colours for new passenger cars, noting a shift away from blues and greens over the past 15 years, while red remains the most popular chromatic colour. He concluded by saying that in future colour design tools will be based on
holistic spatial depictions of colour, linked with scientific colour measurement systems. True colour representations can be linked with psychophysical parameters and sophisticated digital apps will emerge, as marketing tools and technical aids for both the colour technologist and the ultimate consumer. Ms Nathalie Roy (an independent colour consultant, based in Montreal) discussed the essentials of product colour validation, with particular reference to the colour/materials/ finishes (CMF) user-centred design process. She also mentioned the importance of sustainability in the field of materials, highlighting the potential for perovskite-structured solar cells (with high efficiencies and low production costs), for lithium sulfur graphene batteries (supplying power for electric cars) and for light emitting diodes (LEDs) embedded into road surfacing materials so as to supplement or even replace conventional lighting on streets and highways. Dr Jiri Filip (of the UTIA Institute, under the aegis of the Czech Academy of Sciences) spoke about the measurement and visualisation of the appearance of materials, highlighting the use of a gonioreflectometer developed by UTIA. For many applications in the interior design of buildings, in medical diagnoses, in the clothing and footwear sectors and in presenting cultural heritage exhibits, it would be useful to have portable devices capable of rapidly providing reliable measurements of appearance, whether
PIGMENTS
PIGMENTS
PIGMENTS
PIGMENTS
FOCUS based on bidirectional reflectance distribution function (BRDF) or bidirectional texture function (BTF) analysis. Ms Judith Van Vliet (of Clariant) presented a paper titled: "Latest colour design forecasting trends'' and this was followed by a discussion of the factors driving change in the colour pigment industry, co-presented by Mr Bill Eibon (of PPG Industries) and Mr Paul Czornij (of BASF). The afternoon ended with a round-table discussion on colour harmony in automotive applications, with contributions from Dr Trevor Sayer, Mr Mark Nichols (of Ford Motor Co), Ms Barbara Sika (of Porsche) and Mr Aappo Roos (of Gasmet Ansyco). The Friday morning session began with a presentation by Dr WernerRudolf Cramer (an independent consultant, based in Münster, Germany) covering interference pigments and especially holographic pigments, with colour shift between 358 and 658 aspecular. Ms Lisa Clapp (of Sun Chemical) gave an excellent overview of pigmentation theory and colour perception. She said: "For nearly 100 years, scientists have attempted to calculate colour in order to articulate differences. A number of separate algorithms have developed and evolved in attempts to more closely match visual perception.'' These include: the Tristimulus (red-greenblue) approach (1931); Wyszecki's CIEUVW model (1964); and the CIE La-b model (1976); FMCII (1971); CMC (1986); CIE94 (1995) and CIEDE2000 (2001). Colour is a function of absorption and reflectance. Pigments absorb light, with the position and shape of the absorption bands defining the colour; the non-absorbed, mainly reflected, light provides the actual light that provides the ultimate colour. Transparency and colour are directly related to pigment particle size due to scattering components. Mie scattering (rather than classic Rayleigh scattering) dominates in pigments, because the size of the scattering particles is comparable to the wavelength of incident light. Wider particle size distributions broaden the scatter and lower the chroma. The presence of aggregates also lowers the chroma and that is why dispersion of the pigment is so important. Sun Chemical pioneered fractal analysis to determine dispersion characteristics. The entire system – pigment, polymer and substrate – must be considered for transparency. Metameric
2
ON
PIGMENTS
colours have the same tristimulus values for a reference illumination, but a different spectral response. Under different illuminations, the relative shades of the colours change. Thus, there may be a "colour match'' between two different inks in natural sunlight, but nothing like a match under fluorescent or halide lighting. When haze or "milkiness'' occurs if the reflectance or transmission angle is altered, the key factors are normally film formation and surface texture. Whereas scatter is wavelengthdependent aspecular reflectance, haze is wavelength-independent aspecular reflectance. Gloss has a high wavelength-independent specular reflectance, whereas bronzing is exhibited as a wavelength-dependent specular reflectance. In her concluding remarks, Ms Clapp said: "Colour appearance is very subjective and is not easily related to measured perception, which is very difficult to fully describe with algorithms. Returning to the fundamentals of light absorption and light scattering will give the most accurate description. A close study of the wavelength-dependent reflectance spectrum should identify opportunities for colour matching.'' Colour is complicated! Ms Alice Chadwick discussed the human perception of gloss. Historically, it was believed that it should be possible to define gloss with a single objective measurement. That was the principle underlying the Ingersoll glarimeter (1922), for example. But it is clear that in fact multiple factors are involved, notably the direction of illumination, specular highlights, the surface texture, shape, lightness and colour, the viewing distance and binocularity disparity. So what is going on when we perceive gloss? Ms Chadwick said: "It seems that the visual system is using a constellation of cues and pseudocues in making perceptual judgements. The more cues that are available, the better our perception.'' Schlenk (one of the leading global suppliers of metallic pigments) has published a lot of experimental data with the aim of shedding more light on this topic. Dr Thomas Sowade (of Heubach) provided a useful update on the paper he presented at the Nuremberg Conference earlier in the year. (See 'Focus on Pigments', Jul 2015, 2-3). He began by stating that the world's consumption of lead chromate and molybdate pigments has dropped from 120,000 tonnes in 1980 to about 50,000 tonnes in 2010, with no
obvious sign of the downward trend being arrested. He then discussed the five Heubach alternatives to chrome yellow and moly red. Firstly, Heucodur mixed metal oxides with a rutile structure. Secondly, Vanadur bismuth vanadate pigments. Thirdly, Monolite organic red and yellow pigments. Fourthly, Heucofit LR pigment preparations consisting of a blend of organic and inorganic pigments. Fifthly, Heubach's Tico range of so called "hybrid pigments'', manufactured by a proprietary co-finishing process that effectively attaches organic colorants to a titanium yellow carrier pigment. Prof Mas Subramanian (of Oregon State University) is famous for heading the team which discovered the first new blue chromaphore in more than 200 years – the OSU Blue, based on trivalent manganese in trigonal bipyramidal configurations, with yttrium and indium oxides. In his presentation at the Prague Conference, he spoke about the role of serendipity (luck) in making important scientific breakthroughs. This applied not only to OSU Blue, but also to penicillin, Bakelite, saccharin, X-rays, rubber vulcanisation, Vaseline petroleum jelly, Viagra and Perkins's mauve dye. But he reminded the audience of Louis Pasteur's dictum "Luck only favours the prepared mind.'' Prof Subramanian also discussed the principal causes of colour in inorganic solid materials interatomic excitations (d-d shell electron transitions), charge-transfer excitations, valence to conduction band transitions and intra-band excitations. Crystal chemistry plays an important role. It is interesting to note that rubies are red and emeralds are green simply because of trivalent chromium impurities in aluminium oxide and in beryllium aluminium silicate respectively. Prof Subramanian also posed the question: "Why is it so hard to find stable non-toxic inorganic red pigments that could replace cadmium and mercury pigments?'' This segued into the final paper of the Colour Science session, delivered by Dr Andrew Smith (of Shepherd Color), titled: "Pigment design for function and the future.'' He outlined the many different inorganic pigment chemistries and the many different technical and socio-political factors affecting pigment design. He also discussed the spaces beyond the visible spectrum with opportunities for infrared reflecting black and blue pigments and for ultraviolet absorbing pigments. Shepherd Color has February 2016
FOCUS commercialised pigments based on OSU Blue and the complex highperformance inorganic pigments, RTZ Orange (based on rutile TiO2, tin and zinc) and NTP Yellow (based on niobium-tin pyrochlore). Dr Smith also described his company's Starlight coloured effect pigments and Dynamix stir-in pigments. He ended his talk with a quote by Marcel Proust: "The real voyage of discovery consists not in seeking new landscapes but in having new eyes.'' Meanwhile, over in the parallel TiO2 session on the Friday morning, Mr Stefan Rämisch (of WL Gore & Associates) described the use of filter media at the oxidation and milling/ micronisation stages of sulfate-route and chloride-route TiO2 pigment manufacturing processes. Gore now offers membrane filters made of extended polytetrafluoroethylene (ePTFE) as a clearly more efficient alternative to conventional felt fabric filters. He cited a case study of a TiO2 manufacturer who for many years had been satisfied with the use of acidresistant aramid felt filter bags in the dryer baghouses of the plant, but then found that they were inadequate when the production line was switched to making TiO2 pigments grades with smaller particles and increased flowability. After only four months in service, the TiO2 particles were migrating through the stitch-holes. Replacement of the old filter bags with membrane filters made of ePTFE, at the same time as covering the stitchholes with special seam tape, quadrupled the service-life to 16 months. For the final plenary session of the conference, the audiences from the TiO2 session and the Colour Science session coalesced. Ms Joanne Watson (of Walgreens Boots Alliance) discussed her company's application of colour measurement in the cosmetics sector, specifically in the development of the proprietary No7 Match Made customer service for lipsticks, foundations, blushers and concealers. The first step is to carefully define the customer's skintone on a proprietary scale, on the basis of which the most suitable cosmetic type and colour shade can be identified. In essence, this is similar to the approach outlined by Dr Felix Schmollgrüber (of X-Rite) in a paper delivered at the Berlin Conference four years ago (See 'Focus on Pigments', Jan 2012, 2). Dr Fiona Watson (of Henan Billions) discussed the usage of TiO2 in printing February 2016
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inks, the most important TiO2 pigments in this field being the RDI-S product (developed by Kemira in Finland in the 1980s) and the TR-52 product (an upgraded version of the Comet-300 product launched by Tioxide in the mid-1990s). Sulfate rutile grades are by far the most popular products in the inks segment. Chloride rutile grades are generally considered to be too abrasive, while the hiding power of anatase grades is not considered to be sufficient for many applications. In order to gain EU anti-trust approval for the acquisition of Rockwood's TiO2 assets, Huntsman was obliged to promise to divest part of its ink-grade TiO2 pigment portfolio. Effective 1 December 2014, Henan Billions acquired the TR-52 business from the Huntsman group, entailing the transfer of contracts and customer lists, but not entailing the transfer of any manufacturing assets. Huntsman has continued to make the TR-52 grade at the white-end of its Calais (France) sulfate-route TiO2 plant under a four-year toll-manufacturing agreement. Huntsman (with RDI-S) and Henan Billions (with TR-52) are now competitors in the printing inks customer segment. The technology transfer aspects of the deal have proceeded smoothly. It is naturally in Huntsman's interest that TR-52 (as sold by Henan Billions) is qualified for use by all major customers. Dr Watson noted that global consumption of TiO2 for printing inks now accounts for just over 200,000 tonnes/y of TiO2, of which 90-95% is for packaging inks. The rest is mainly accounted for by white inks in the publications sector. Asia/Pacific accounts for 48% of the TiO2 consumed in printing inks; Europe for 26%; North America for 13.5% and the rest of the world for 12.5%. The global packaging industry is huge, being currently worth more than $950 bn. The consumption of packaging inks, by type of packaging, breaks down as: 56% flexible; 18% cartons; 14% metal (cans, etc.); 7% corrugated board; and 5% rigid plastic. Flexible packaging is destined to be the fastest growing sector in the medium-term future, with cartons also showing rapid growth. Increased demands for packaging functionality dictates a requirement for speciality inks for microwavable packaging, stand-up pouches, aseptic packaging and packaging with good barrier properties. Labels for pouches and shrink-film packaging are often reverse/reverse laminated, which necessitates particular TiO2 properties.
There is also a definite trend towards printing on highly glossy surfaces for strong visual appeal. Printing inks are most commonly solvent-based. In fact, water-based inks currently account for only about 10-20% of total world inks production. UV-curable inks currently account for around 10% of total output, but this sector is destined for rapid growth in the future. The global printing ink industry is much less fragmented than the paint industry. In fact, the top five inkmakers – DIC/Sun Chemical. Flint, Toyo Ink, Sakata and Siegwerk – account for about 60-70% of global ink production. Further small-scale mergers are likely to lead to further industry consolidation in the mediumterm. There are no obvious signs of the emergence of any major Chinese printing inks manufacturer. At present, the Chinese printing ink industry is relatively small and quite fragmented. Clearly, Henan Billions is determined to boost its share of the printing inks segment of the TiO2 market in the future. The final paper at the Prague Conference – on the topic of TiO2 consumption in the plastics industry – was delivered by Mr Rémy Jury (of Profialis). About 1.5 M tonnes/y of TiO2 is currently consumed in the plastics industry. Polyvinyl chloride (PVC), in both rigid and flexible forms (uPVC and sPVC) accounts for about 17% of total world plastics consumption. Polyethylene accounts for 34%, polypropylene for 20%, polystyrene for 9%, polyurethane for 5%, polyethylene terephthalate (PET) for 5% and a variety of other polymers for the remaining 13%. Shin-Etsu is the world's leading PVC producer (with a capacity of around 3.5 M tonnes/y), followed by: Formosa Plastics (3.2 M tonnes/y), Solvay (2.5 M tonnes/y); LG Chem (2.5 M tonnes/y); ChemChina (2.1 M tonnes/y); Ineos (1.75 M tonnes/y) and Oxyvinyls (1.75 M tonnes/y). Smaller suppliers include: Tianjin Bohai, China National Salt Group (CNSG), Shanghai Chloralkali Chemical (SCAC), Axiall, KemOne, Vinnolit and Westlake. The construction industry accounts for about 56% of global PVC consumption. Profialis (owned by the Open Gate Group, a private equity fund) is one of the top five producers of rigid polyvinyl chloride (uPVC) window and door profiles/frames in France. Like many other TiO2 consumers, during the 2011/12 price surge, Profialis took steps to minimise its TiO2
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FOCUS consumption. In 2000, the typical formulation of a white uPVC window profile comprised: 75% base polymer, 10% TiO2, 5% CaCO3 and 10% other additives. By 2010, the typical formulation had changed to: 75% base polymer, 3% TiO2, 12% CaCO3 and 10% other additives. Thus, unit consumption of TiO2 was reduced by about 70%. Mr Jury acknowledged that 3% seems to be the lowest acceptable level of TiO2 for a suitable uPVC product in outdoors applications. He also pointed out that white is no longer quite as dominant as it used to be. In 2005, only 3% of the uPVC profiles sold on the French market were coloured, whereas the proportion had climbed to 25% by 2015. Another method employed for thrifting on TiO2 usage is to move to a co-extruded product, where only the external layer of uPVC incorporates TiO2 to provide weatherability, while the internal layer contains no TiO2. Nevertheless, the volume growth of PVC worldwide is so strong that despite sharp reductions in unit loadings in a variety of applications in construction, packaging, transport, wire and cable sheathings and consumer products, the overall consumption of TiO2 in PVC products is likely to increase. Besides the themes of conventional TiO2 pigments, effect pigments, colour pigments and the quantification of aspects related to colour and gloss perception, the theme of nanotechnology featured strongly in the Prague Conference. This was emphasised from the outset, when Dr Pavel Belobradek (Deputy Prime Minister of the Czech Republic) noted, in his opening address, that the country is already well established as a global centre of excellence for nanotechnology, with more than 30 flourishing companies specialising in this field. Nanoparticulate TiO2 has a wide range of applications in catalysis, in photovoltaic cells, in effect pigments and in ultraviolet absorbers, with plenty of scope for development. Dr Jiri Kus (of the Czech Nanotechnology Industries Association) spoke about the current EU regulatory framework, as it affects nanomaterials. As in the past, the advent of new technologies – mechanised knitting machines and weaving looms, aircraft, radios, microwave ovens and industrial robots – can be handicapped by an outbreak of mass media hysteria. The nanomaterials industry needs to combat "scare stories'' by presenting convincing experimental evidence of benefits and
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advertising popular examples, such as providing drinking water for astronauts, hypoallergenic fabrics and furnishings, storage devices for renewable energy and nano 3-D printers for making human organ replacements. Dr Jan Buk (of Pardam) spoke about his company's business, making nanofibres for a variety of applications. Pardam's product portfolio includes NnF Ceram, made from anatase TiO2, which can be used in air/fuel ratio controllers in vehicle engines, humidity and gas sensors, solid oxide fuel cells, and anti-pollution catalysts. Dr Jiri Bezdicek (originally trained in the Czech Republic and now working at Levenger, Spain) highlighted the use of nanoparticulate TiO2 for water treatment applications. Levenger's FNAQUA (based on nanoparticulate TiO2) can remove pathogenic bacteria, organochlorides and all non-metallic priority organic pollutants from waste water at an operating cost of less than €1.50 per kilolitres and with no adverse environmental effects, unlike conventional hyper-chlorination methods. Prof Josef Krysa (of the University of Chemistry & Technology, UCT Prague) explained the theoretical principles behind nanoparticulate TiO2's properties as a photocatalyst, especially for removing nitrogen oxides, acetaldehyde and general organic debris (dirt). He also showed examples of its use in self-cleaning paints, glass, ceramics and concrete. Finally, he spoke about the use of RZ ink as an indicator of photocatalytic activity developed by UCT Prague in collaboration with Queens' University, Belfast under the EU's Intec programme. A pen filled with RZ ink can be easily used to test the effectiveness of samples of selfcleaning ceramic tiles and other products. Dr Jan Prochazka (of Advanced Materials JTJ) gave a very comprehensive review of applications for nanoparticulate TiO2 in environmental remediation, citing figures for the estimated market potential for annual nano TiO2 sales revenue in the Czech Republic alone as: $3 M for self-cleaning building facades, $0.7 M for historical monuments preservation; and $1.5 M for graffiti removal. He also discussed applications for nano TiO2 in water decontamination, especially in areas containing dioxins and other organochlorine pollutants, public health protection and odour removal.
At the end of the first day of the conference, over 120 delegates enjoyed an evening cruise in a boat on the River Vltava, with a meal, wine and schnapps, all generously funded by Dr Prochazka's company – a subtle indication that the profit margins achieved by this nano TiO2 producer are currently very much healthier than those of the conventional pigment producers! For those who were unable to attend the event, the full set of published papers from the Prague Pigment & Colour Science Forum & TiO2 World Summit conferences (8-9 October 2015) is available for sale. For details, please contact: Ms Sharon Garrington, SmithersRapra, Shawbury, Shrewsbury, Shropshire, SY4 4NR, England. Tel: +44-(0)1939-250383. E-mail: sgarrington@ smithers.com
MARKETS Average Chinese rutile TiO2 price raised to Rmb 10.15 per kilo ($1562 per tonne) China's TiO2 pigment production fell last year for the first time since 2008. According to preliminary data issued by the China National Chemical Industry Productivity Centre (CNCIPC), production for full-year 2015 was 2.323 M tonnes, indicating a 4.5% fall on the 2014 figure. Meanwhile, despite the closure of more than a dozen small and medium-sized plants during the 2012-2015 period, there was still a wide margin of overcapacity in the Chinese TiO2 industry, of the order of 30-40%. Towards the end of last year, several producers reduced their operating rates in order to avoid a build-up of inventories and with a view to trying to stem the steady downward drift in prices. By the end of December 2015, the average domestic price for rutile-type pigment had dropped to Rmb 9.75 per kilo (equivalent to $1500 per tonne). At that level, virtually all producers were failing to cover their cash costs of production. Effective 6 January 2016, Sichuan Lomon (the largest Chinese producer, with a capacity of around 300,000 tonnes/y) declared that it was raising its TiO2 pigment prices by Rmb 0.30 per kilo (equivalent to $46 per tonne). Most of the other leading suppliers – CNNC HuaYuan, Henan Billions, Bluestar and others – followed suit. Encouraged by this success, Sichuan Lomon posted a second price increase of Rmb 0.30 per kilo on 26 February 2016