The choice of the correct adhesive and adhesive supplier can be a crucial factor in the long-term success of disposable hygiene product manufacturers. 

Sustainable Nonwovens asked Sharon Situ, global forecasting manager of strategic sourcing at H.B. Fuller to explain the options and provide the bigger picture. 

SNW: How much does the global crude oil market impact on the performance of businesses manufacturing absorbent hygiene products?

Sharon Situ: As a global adhesives supplier to the hygiene industry, our raw material feedstocks are by-products of the petrochemical industry so – as with a number of other suppliers of components for hygienic disposables – we have a certain dependency on the oil price. Even with the crude oil price being so low, this doesn’t necessarily reflect in the adhesive supply or cost chain, which is often multiple steps away from crude oil and competes against other materials utilising the same feedstock. It’s the supply and demand situation which sets the prices for our direct raw materials used in hygiene adhesives. In the past, it’s been a combination of these factors that has resulted in volatility in prices and in some cases shortage of supply.

SNW: What about the cost ratio between crude oil and natural gas?

SS: This is also now important in terms of raw material prices and their availability for the adhesives industry. A high crude oil-to-natural gas ratio pushes the cracking of more light feeds in favour of heavy feeds. And despite the price of crude oil being low right now – and continuing to fall – the low price of natural gas still makes light feeds favourable for ethylene cracking. The by-products produced by cracking light feeds are greatly reduced as compared to cracking with heavy feeds.

SNW: So what effect will this have?

SS: It means that, for adhesives which are highly dependent on by-products from  heavy feeds, there will be no significant improvement on adhesive feedstock availability under the current low crude oil price. Adhesive raw materials are also competing with transportation and heating fuels on feedstocks, so the seasonality of demand for these fuels has a clear influence on the adhesive feedstock supply.

SNW: What are the ways of managing this risk?

SS: Feedstocks from the petro-chemical industry are really the only current effective way to ensure adhesive performance, however H.B. Fuller is constantly seeking ways to enhance supply assurance by researching alternative technologies. The company has been fine-tuning its metallocene olefin – mPO – adhesive technology for absorbent hygiene products, having taken the lead, over a decade ago, in recognising its potential for increased stability of supply and reduced price volatility. This continues today due to the anticipated increased production of propylene.

SNW: The amount of adhesive in an average diaper only constitutes around three per cent of the overall product though, doesn’t it?

SS: It does, but it’s critical; adhesive not only bonds hygiene products together, but also has an impact on the overall performance of the final end product.

SNW: What about the US growth of the shale gas-based petrochemical industry? Doesn’t that also bring new opportunities for increasing feedstock and raw material choices?

SS: It does, and this is the case now, not just in North America, but in parts of Europe and other countries like South Korea and Japan. Petrochemical development, however, varies from region-to-region and there is still a lot of potential to better utilise by-product or co-product feedstocks from current heavy feeds-based ethylene crackers in emerging markets, which is leading the growth in absorbent hygiene currently.

SNW: Can you say a little more about mPO adhesives and how they differ from other products on the market?

SS: The other primary polymer technologies designed for hot melt adhesives employed in the construction of absorbent hygiene products are styrene block copolymers (SBCs) or variants based on synthetic rubber and amorphous poly-alpha-olefins (APAOs). SBCs have a wide operating window and proven performance, which traditional olefins have challenges to meet. Unlike the catalysts used in traditional APAOs meanwhile, metallocene catalysts allow fine control of chemical structure, molecular weight and all the performance characteristics affected by an adhesive’s chemical structure. Properly designed, mPO-based adhesives can provide excellent adhesion at lower total cost than either those based on SBCs or APAOs and over the last decade they have certainly shown greater price stability than them. In addition, they have an excellent odour profile, typically spray well, and their improved thermal stability cuts down char and gel, which reduces clogged filters or nozzles, reducing maintenance time on the lines.

SNW:  Hasn’t the odour associated with SBC polymers also been cited as a growing concern?

SS: End consumers appear to be more sensitised to the odour of a diaper, particularly when first taken out of the pack. So, the additional benefit of olefin based technologies having an excellent odour profile, supports this growing market need. But historically, the biggest and acknowledged challenge is the availability and volatility of raw materials.

SNW: What choices are open to manufacturers to help them manage their business risks and ensure they remain competitive?

SS: For manufacturers, adhesive selection represents a commitment in terms of investment, supply chain logistics, process design and ongoing operations. As in all business decisions, total cost is a key driver, and calculating that cost can be quite challenging, since while the price is important, the impact on line performance, cost in use, supply assurance and responsive service and support can all impact on the bottom line. Of course, in terms of managing supply risk, it’s important to find an adhesive supplier with the flexibility to cover from all technology bases and the proven history in supply assurance.

SNW: How easy is it to switch to new products, or between the options?

SS: We understand switching is time consuming and takes up precious line time, so with the support we offer, the switch can be well planned and executed. We have a wealth of experience in successful and efficient change-overs to olefin based technologies – it is part of our Full-Care support package to customers. And any new product from H.B. Fuller has been through a set of rigorous testing procedures, both in our lab, via our predictive modelling capability, and on our in house coaters, to ensure the product is ready to run on the lines of customers, to avoid unnecessary downtime. Looking to the future, olefin-based technologies are likely to offer more sustainable supply, which is why we have pioneered them.

Olefin technology has moved to a new level but can be confusing due to the different types available. H.B. Fuller’s new Olefin white paper can be obtained from http://bit.ly/RequestOlefinPaper