A revitalised US manufacturing sector and demand for higher-quality products has spurred innovation with hot-melt adhesives using metallocene polymer developments
The full impact of lower-cost shale gas on the American manufacturing sector is being realised today, with much of the conversion from heavy liquids and naphtha feeds to natural gas having taken place across the US. Abundant US shale gas supplies are revitalising the petrochemical industry, particularly chemical manufacturing including the production of adhesives and sealants.
At the same time, customers of products made with adhesives and sealants demand higher-quality goods, which is driving innovation and improvements in resin technologies and a shift towards solvent-free options such as hot-melt adhesives, says Dwight Tozer, vice president of the Adhesion Industry Business with ExxonMobil Chemical.
ExxonMobil’s Chemical Plant in Singapore provides a unique and strategic platform for the world’s largest hydrogenated hydrocarbon resin plant
He adds that the abundant, competitive natural gas supply now available in the US provides a very strong foundation for increasing economic output, opening up new and valuable opportunities in many regions and sectors of the economy, including industrial sectors such as steel, auto manufacturing, and plastics.
“Expanded natural gas production is allowing chemical and plastics manufacturers to create jobs and increase sales both to domestic and global markets. The lower-cost energy, increased supply security, job creation and enhanced global competitiveness that has resulted from the development of shale gas is providing true advantages for the manufacturing sector in the US,” he observes.
TECHNOLOGY IS KEY TO SUCCESS
The key to the successful development of shale gas has been the combination of two pre-existing technologies: hydraulic fracturing, or fracking, and horizontal drilling. Fracking has been used for more than 60 years, but until recently only with conventional vertical wells. When combined with horizontal drilling, which was developed in the 1980s, it is possible to access gas and oil located in pockets trapped between shale layers a mile or more below the surface.
The process involves boring a hole thousands of feet straight into the ground and horizontally through the shale. Water, sand and a small quantity of chemicals is injected into the hole under high pressure, which causes small fissures to form in the rock. The cracks remains due to sand penetration, and the gas and oil can flow through the well once the water is removed.
BOON OR BUST
While access to cheap shale gas is a boon for US chemicals, there have been consequences for the supply of certain feedstocks that are not generated in significant quantities from natural gas. For the adhesives and sealants industry, production of C5 olefin feedstocks has been affected and there was a significant decrease in the supply of compounds such as isoprene, piperylene, and dicyclopentadiene (DCPD), the latter two of which are important for the synthesis of adhesive and sealant resins, says Tozer.
He stresses there has been little impact on the overall availability of these key ingredients for ExxonMobil as several new fractionation recovery units are now operating in Asia-Pacific and at least two more are being built.
“While many North American resin producers are now importing C5 raw materials that they previously had direct access to, the new production capacity in Asia-Pacific has kept up with demand,” Tozer asserts.
One area where shale gas supply has had a positive and dramatic impact has been the increased ability of US manufacturers to invest in R&D and innovation, and that has certainly been true in the adhesives and sealants sector.
“There is a real emphasis on innovation in the sealants and adhesives sector, and particularly with regards to polyalpha-olefin technology,” says Tozer, adding that a notable developments was using metallocene chemistry to produce resins for adhesives and sealants.
“The use of metallocene catalysts for the polymerisation of PP and PE results in very homogeneous polymers with specific structures that can be controlled by the choice of catalyst. As a result, it is possible to produce polymers for hot-melt adhesives that possess the ideal level of crystallinity and flexibility for excellent adhesion to multiple types of substrates,” he explains.
“Manufacturers of hot-melt adhesives are therefore well-positioned today to respond to key drivers in the marketplace, the most significant of which is the expectation of much higher-quality products, particularly in the hygiene market,” he adds.
Diapers (nappies) are the leading product in this segment and new mothers are looking for products that have no odour or colour to them.
“Diaper manufacturers therefore prefer higher-performing adhesives based on hydrogenated resin and metallocene-based polymers rather than more conventional adhesive formulations,” Tozer notes.
The packaging market, meanwhile, is looking for what Tozer refers to as “trouble-free” systems that enable ever faster production line speeds using adhesives with long pot lives for longer run times and that do not cause shutdowns due to clogging.
“In packaging, there is a significant push to boost productivity and efficiency in order to lower production costs,” he explains.
A third big trend in the adhesives and sealants industry that crosses all end-use markets is the increasing regulation of volatile organic compound (VOC) content in products.
The restriction of VOCs in both adhesives and sealants and throughout the value chain has a real impact on choices that downstream users are making with respect to adhesive and sealant technologies and chemistries, he says.
“We are seeing a switch from solvent-based adhesives to hot-melt adhesives, which provide a good alternative with respect to performance, particularly for hot-melt adhesives based on polyalpha-olefin chemistry,” he says.
ExxonMobil’s outlook for the hot-melt adhesives market is positive. “We see the hot-melt adhesives market growing at 5-6% annually and doubling within 15 years. Not surprisingly, the greatest growth will be in emerging markets and the hygiene market in particular will see growth rates double the average,” Tozer notes.
The challenge for resin manufacturers such as ExxonMobil will be to maintain a stable supply of high-quality products that enable customers to achieve maximum growth, he adds.
“We must avoid the experiences of the past where shortages led to resin producers placing customers on allocation. It is imperative that we keep pace with the demand for adhesives and sealants, and I believe that the industry has responded well to this challenge, with several new projects already in place or announced.”
Continued innovation will also be critical. “We are committed to developing next-generation tackifiers that will help our customers meet the expectations of consumers for higher-quality products. Substantial innovation is required to meet ever-increasing performance needs, but the industry, including ExxonMobil, is committed to developing products that are demanded by the market,” he concludes.
ExxonMobil planning to Construct World’s Largest Tackifier Plant in Singapore
ExxonMobil will be ensuring that its customers have a consistent supply of the highest quality hot-melt adhesive resins when its recently announced facility for the production of Escorez 5000 hydrogenated tackifier comes on stream in 2017. The new plant in Singapore will be supplied by two steam crackers that, using novel proprietary technology, directly convert multiple feeds including crude oil to petrochemicals that are ideal for adhesives applications, according to Tozer.
“These two crackers can produce C5 feedstocks equivalent to the amount obtained from 8-10 naphtha crackers. As a result, we are able to construct a 90,000 tonne/year plant for hydrogenated tackifiers, which is 40% larger than the largest existing plant in the world,” he says. “Unlike conventional tackifier plants that typically must source feedstock from third parties, we will be able to fully supply the new tackifier plant directly using our proprietary cracker technology,” Tozer adds.
Construction is scheduled to begin in the second half of 2014 and will nearly double ExxonMobil’s capacity for tackifiers for hot-melt adhesive applications.
The tackifiers themselves will also be produced using next generation technology developed at ExxonMobil. In addition, these products have low odour and low colour and are ideal for adhesive applications. Resins for non-adhesive applications will also be manufactured in the new facility.
“ExxonMobil is recognised as a leading source of globally consistent, high-quality and technically advanced polymers and tackifiers for the hot-melt adhesive industry,” Tozer asserts.
“Our new plant marks another milestone in our ongoing commitment to help formulators serving the packaging, woodworking and nonwovens markets around the globe capitalise on growing demand for premium, hot melt adhesives.”
He also notes that the selection of Singapore as the location for the new plant will enable ExxonMobil to quickly supply Escorez 5000 tackifying resins to hot-melt adhesive manufacturers across Asia Pacific and around the world.
ExxonMobil also has hydrogenated resin capacity in Baton Rouge, Louisiana, and Notre-Dame-de-Gravenchon, France.