By Andrew Jackson, Head of Project Management, OBAs, Clariant
BRUSSELS,
May 31, 2009
(Viewpoint) -
Optical brightening agents (OBAs) based on diaminostilbenedisulphonic acid (DAST) were introduced as long ago as 1940, yet remain the most cost effective means of raising the whiteness level of paper. Indeed, their use in recent years has increased substantially as the North American market has moved towards the higher whiteness levels favored in Europe, and demand is likely to continue to grow as markets in the Far East expand. Since their first introduction, DAST-OBAs have been subjected to the most stringent toxicological tests and have retained throughout an excellent safety profile. Certain grades have approval for use in food-contact papers and boards under FDA limitations.
The second half of 2007 saw the start of an extremely turbulent period for OBA producers and customers alike that was fuelled by increases and reported shortages in key raw materials. Towards the end of 2008, raw material prices relaxed, then fell dramatically as the global economic downturn kicked in. Moving into the 2nd quarter of 2009, the future remains very uncertain. Nevertheless, there is room for encouragement, as opportunities remain for innovative OBA producers to deliver even more cost-effective solutions for their customers. The aim of this article is first to summarize the recent developments in OBA pricing, then to look forward to how the OBA producers might respond to new legislation and market trends.
Developments in pricing
The background to the price explosion in OBA raw materials and its effect on OBA pricing has been discussed (PPI, October 2008). Briefly, the situation was a result of a combination of factors including the abolishment of the VAT refund on OBAs and other key chemicals from China, the closure of one of the largest Chinese producers of DAST, the Olympics' restrictions on the production and transport of hazardous chemicals in the area of Beijing, and a slowdown or stoppage in the production of para-nitrotoluene (PNT), the direct precursor of DAST. The problems were not restricted to the Far East but extended to a shortage of another key raw material, cyanuric chloride (CYCL), in Europe. By June 2008, the price of DAST out of China had increased by 450% over 12 months, and the price remained at that level or higher until after the Olympics. Other key raw materials had typically risen in price by 100-150%. At the same time, there was no guarantee of supply over the coming months; some OBA producers brought in additional stock to protect their customers against potential raw material shortages.
Although spot prices for raw materials out of China began to fall in the final quarter of 2008, production costs for OBAs remained at a high level until 2009, not only because of the long lead time for deliveries but also because of the need of producers to work through existing stock at the same time as the economic downturn began to take hold.
The rapid and severe impact of the downturn has now led to raw material prices falling more quickly than could previously have been expected. As a consequence, OBA prices have fallen in line as far as lead times and stock pricing have allowed. The key factor driving prices at this time is demand - once demand picks up, prices are likely to increase. Adding to the uncertainty over future price developments are the unpredictability of energy costs and raw material availability, and the issue of limited competition to Chinese suppliers. Encouragingly, moves are being made to address these last two issues.
What are the other significant developments with a present or future effect on the OBA market?
Reach legislation
REACH, the European Union (EU) law designed to ensure the safe use of all substances produced in, or imported into, the EU, came into force in 2007. REACH will require the registration before 2018 of some 143,000 existing chemical substances, though there are earlier deadlines for substances sold on to the EU market at a level of 100 tonnes/yr or more.
An important point is that substances that have been approved under the previous NONS (Notification of New Substances) regulations are already considered to be fully registered under REACH. Therefore, the more innovative of the European OBA producers are able to offer several products containing REACH-registered brighteners; Clariant, for example, has REACH-registered disulpho, modified-tetrasulpho, and hexasulpho brighteners.
As a prerequisite to benefit from the REACH transitional period to 2018 (or earlier), producers and importers were obliged to pre-register so-called "phase-in" substances (that is, substances listed in EINECS, or those that have been manufactured in the EU, but not placed on the EU market, in the last 15 years). Consumers are well-advised to ensure not only that producers have pre-registered their products, but that they can provide proper justification for having done so.
Carbon footprint
Despite comprehensive studies made over several decades indicating that DAST-OBAs present no hazard to the environment, questions continue to be raised on their environmental impact. (For a summary of toxicological and environmental studies, see Thomas Roick, Optical Brighteners in Fine Papers, 1999 Papermakers Conference.)
Most recently, customers are increasingly asking for carbon footprint calculations. In response, Clariant last year commissioned an external consultant to make an in-depth analysis of the emissions resulting from production of a standard tetrasulpho liquid OBA. The analysis took into account carbon dioxide, nitrogen oxide and methane emissions resulting from power, crude oil and logistics components. A final estimation of a carbon dioxide equivalent was then calculated using IPCC values for Global Warming Potentials. Working from published data, the figure obtained represents considerably less than 0.5% of the carbon dioxide equivalent of printing and writing papers. The clear conclusion is that OBAs have a relatively insignificant effect on global warming.
Recycled fiber
Although recycled fiber (RCF) currently represents only a small proportion of the pulp used to produce printing and writing papers, it is clear that this will change as consumer demand grows for products which are seen to be more environmentally friendly. Not only is there an opportunity for papermakers to introduce products with a greener image, but the trend towards increased use of RCF also presents the OBA producer with the challenge and opportunity to offer new products with improved performance on RCF.
Some OBA producers are already introducing products which offer an improved compatibility with RCF. Clariant, for example, recently introduced its Leucophor® V-range which, although primarily intended for coating applications, can provide a significantly higher level of whiteness in size-press applications on RCF grades than can be achieved using conventional OBAs. The effect is illustrated in Fig. 1 by the comparison of whiteness build-up on 100% recycled paper between Leucophor® VM liq and two conventional OBAs.
There can be little doubt that the design of OBAs for use on recycled fiber offers plenty of scope for innovation in the future.
ColorLokTM technology
There is a lingering belief within the industry that within a particular product group - disulpho, tetrasulpho (standard or modified) or hexasulpho - OBAs are interchangeable. The recent emergence of ColorLokTM technology demonstrates this to be a myth, and provides a good example of how papermakers can optimize costs by careful selection of the OBA.
ColorLok technology was first unveiled by HP and International Paper late in 2005, and is seen at its best in papers for the pigmented inkjet market. The technology relies on a surface additive that binds to the pigment to hold it closer to the surface. Advantages include shorter drying times, bolder blacks, more vivid colors and improved sharpness. At the time of writing at least nine major paper producers have announced their support of the ColorLok paper standard and it is clear that that a significant proportion of the world's uncoated office papers already meet the standard. Further details can be found at www.colorlok.com.
ColorLok technology does however place special demands on the OBA when the brightener is applied as preferred in a size-press application together with the additive and a binder. An examination of Fig. 2 and 3 shows not only that there are very significant differences in ColorLok performance between standard tetrasulpho, modified tetrasulpho, and hexasulpho OBAs, but also that the differences are greatly magnified under ColorLok conditions.
Even within a particular product group, the structure of the OBA has a considerable impact on its compatibility with ColorLok technology. Figure 4 provides an example of this in a comparison of whiteness buildup between two commercially-available hexasulpho OBAs. The point is further made in Fig. 5 which shows the shade development under ColorLok conditions as the OBA concentration is increased; greening can be practically eliminated by choosing the most appropriate OBA.
In conclusion, although ColorLok technology places new demands on OBA chemistry, the obstacles can be overcome by the correct product choice. For medium-to-high whiteness papers, modified tetrasulpho OBAs such as Clariant's Leucophor® N liq can be used to good effect, but for the highest whiteness levels, special hexasulpho OBAs such as Clariant's Leucophor® SHR liq offer a cost-effective solution.
Summary
Despite the difficulties faced by OBA producers and customers alike in the midst of the current global economic downturn there is still room for innovative producers to develop and to introduce onto the market new products offering more cost-effective, safe and environmentally-sound solutions for the customer. There is every reason to believe that OBAs have a bright future.
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