Using new technology to target tissue markets.
EQUIPMENT AND CHEMISTRY DRIVE TISSUE IMPROVEMENTS
By John Stitt, Buckman Laboratories, Memphis, Tennessee, USA
The most successful technology is tight process control from the pulper through converting. Profitability is based on high manufacturing efficiency more than on engineered quality. Anything that can reduce sheet off the reel time or speed up production is a plus. For the economy market segment, some effective techniques I have seen are:
* Tight control of wet end chemistry: Consistency control has long been the most significant factor in almost every tissue manufacturing operation. Charge control runs second behind it. Retention, strength, softness, and color variations correlate with variation in charge. In creping, charge variation can have machine tenders chasing their tails trying to adjust adhesive and release balance. These all lead to lower speed and less good sheet on the reel time.
* Control of stickies in secondary fiber: This area has evolved rapidly and dramatically. First, dispersion/dilution was the solution. Then, with mill water system closure, dilution was no longer possible and even dispersed concentrations increased, producing dramatic crises. Next came dispersion and fixation, taking microscopic stickies out of the system with the fiber of the sheet. Dilution-fixation is technically complex and relatively costly. It is dependent on very tight and effective process control. Now, the leading edge technology involves enzymes that denature the stickiness of the adhesives/coating contaminants--a much simpler application to manage.
* Creping doctor blades and Yankee surfaces: In many mills, the ceramic edge or other hybrid high tech blade designs have come of age. Still, only a few mills are routinely using these high tech blades. Blade manufactures have resolved issues with the "delicateness" of ceramic blades and mills are seeing more blade life. Ceramic blades require different setup, but crews are starting to get the feel for how to run them efficiently so that they reduce the cost per unit of tissue produced.
Specialized dryer surfaces are coming of age too. Poor adhesion of the metallized surface to the cast iron base, the grinding off of the specialized coating in frustration and returning to cast iron, too much smoothness and coating not sticking to the surface--those days are mostly gone. Yankee dryer chemical coating manufacturers have learned how to adhere their coatings to the new surfaces along with understanding the surface requirements for good chemical coating adhesion to the metalized surface. Along with good wet end chemistry control, metalized surfaces are extending machine efficiency and profitability through less lost production due to Yankee dryer surface defects.
In the premium market, several trends have emerged:
* The advent of ECF and TCF pulps: Pulp bleaching technical innovations are being driven by environmental factors. For a number of reasons these pulps do not behave the same during creping. Much of the burden here will fall to the coating chemistry suppliers.
* Crescent formers and TAD rule. Throughout the world, most of the new machines being built are crescent formers. They are faster and work well for lightweight sheets, but are sometimes temperamental. In First World countries where markets will bear the cost, Through Air Dryer (TAD) machines are the dream of every significant premium manufacturer.
ADDING VALUE TO PRODUCTS, EMPOWERING THE MILL
By Harold Goldsberry, Marketing Director, Bayer Chemicals
We see a clear focus on two key areas:
* Chemistries that can add value by contributing unique functional properties (primarily the premium segment).
* Chemistries that can empower the mill to reduce total system cost while maintaining quality (all segments)
A growing trend is the emphasis on softness and strength. These tend to be mutually exclusive properties, as steps that improve sheet strength tend to degrade softness. However, there is a clear marketing opportunity to provide the consumer with both attributes. In the area of toilet or bath tissue, temporary wet strength is a desired feature in premium grades. The temporary nature (or decay) of the wet strength development can be varied, depending upon the design of the chemistry. Tissue producers can now produce these grades with desired wet strength properties as well as excellent softness.
With the increasing shift to TAD machines, producers must manage the lower sheet strength that results from the more open, lower density sheet. Both wet and dry strength resins have a role in maintaining sheet strength and integrity in this low basis weight, high bulk sheet.
In towel grades, producers want higher and higher levels of wet tensile with permanent wet strength resins. The goal is a high "wet-over-dry" value, implying a strong yet softer consumer towel. There is a real opportunity to find ways to exceed the current technical limitations of today's polyamide wet strength resins. Two approaches are in play here. The long term, ultimate answer would be to find a new wet strength technology offering higher performance. The other approach is to extend the performance curve of the cationic wet strength resin with anionic materials. We have developed a new class of chemistries called Functional Promoters that can replace older, more cumbersome technologies, such as CMC. These new liquid products can have a significant impact on reducing total cost or increasing wet strength performance.
CREATING NEW TISSUE QUALITY BENCHMARKS
By Jeffrey C. Peters, business manager-tissue and towel, Hercules Pulp and Paper Division
The three tissue segments have very specific needs. For example, to meet the premium brand customer requirements, more mills are investing in TAD technology. While the upfront cost is high, long-range returns are lucrative. Recent new developments in Hercules ProSoft[R] tissue softener/lotion technology and Crepetrol[R]/Rezosol[R] coating package technology is allowing premium producers to set new softness/handfeel benchmarks for the tissue industry.
Mid-range products have always been in a difficult position as they try to distinguish themselves from the economy brands, while not taking volume away from the premium segment. The right mix of assets, fiber, furnish, and chemicals is critical to the success of this segment. The mid-range producers are also effectively using Crepetrol[R]/Rezosol[R] coating package technology to upgrade their products.
The economy market producers are continually looking for ways to lower the cost of their products. Historically, the focus has been on lower cost per pound chemicals. However, several economy producers are now using Hercules' Crepetrol[R]/Rezosol[R] premium creping package to deliver significant productivity benefits through improved sheet quality, reduced downtime, faster machine speeds and improved asset preservation.
Some smaller/independent tissue producers are beginning to move into the premium branded product segment and are introducing private label brands with excellent quality. These smaller producers will rely more heavily on their suppliers to provide the technology (mechanical and chemical) needed to compete in this segment.
TARGETED CHEMISTRIES FOR TARGET MARKETS
By Gary Furman, program manager-tissue and towel grades, Nalco Company, Naperville, Illinois, USA.
Chemistry is a key input into technology supporting differentiated tissue markets. In terms of Yankee coating technology, the concept of "coating space" allows for customized programs to meet the different technology platforms of the global marketplace. Yankee coating technology continues to develop to support the premium tissue market segments. For TAD technologies, multi-component coating packages support high adhesion creping. The individual components of the coating--including adhesives and modifiers--allow manipulation of the coating hardness, adhesion, and durability to maximize sheet properties such as softness. The TAD process demands different properties than conventional light dry crepe and will require chemical companies to go beyond conventional thinking.
For mid-range and value segments using Crescent formers, coatings are being designed that support the high moisture webs transferred to the Yankee dryer. Here, durability and high adhesion are critical coating properties that can be affected by modifiers and release agents. For the price sensitive marketplace, which is still demanding increased tonnage, runnability and protection of the Yankee are critical coating properties. This requires coating packages with lower adhesion and higher durability. These can be used with specialty formulated release agents to drive improved efficiency.
Strength chemistries continue to be developed to support both the premium and value segments of the marketplace. For bulky, less densified TAD sheets, "architecturally designed polymers" will allow manipulation of the dry and wet strength values of the sheet. These polymers are designed for specific sheet properties and allow alteration of the wet/dry tensile strength ratios. For both the premium and value segments, strength management is critical. The ability to integrate formation, strength and drainage in the wet end is critical in managing strength additives' effectiveness and efficiency.
STRATEGIES FOR "BRANDED VS. GENERIC" PRODUCTS
By Paul Hood, product manager-tissue, North America press fabrics; John LaFond, product manager-tissue, North America forming fabrics; Jim Prickett, North America technology director-tissue, Albany International Corp., New York.
Today, the differences between the premium "branded" tissue market and the "generic" tissue market has never been greater. This is particularly apparent in Europe. The price-driven generic approach places a high emphasis on speed, efficiency, and flexibility. Machine speeds approaching and exceeding 6500 fpm will become common.
Premium tissue products rely on feel, softness, absorbency, and bulk to differentiate their products. Current machine technology for all market segments includes Crescent formers, TADs, and shoe presses. All of these approaches have placed a higher demand on paper machine clothing.
The Crescent former concept offers flexibility and lower initial cost. More than 85% of new tissue machines in Europe in the last five years have used the Crescent former concept. Most major projects in Asia have followed this route as well. TAD applications continue to flourish in the United States, with three installations in the last two years.
Reduced Nip Impulse Pressing--which produces products that can better compete with TAD products--has been gaining momentum. Other approaches along this line (which maintain bulk) are larger diameter rolls, single pressure roll setups, softer rolls and shoe presses. The newest approach, shoe pressing, is currently (or by year end) being used on 12 tissue machines worldwide, of which six are in Europe, five in the Americas, and one in the Middle East.
These newer machine technologies have placed higher demands on forming and press fabric designs. Forming fabrics have to drain faster, provide better fiber support, and transfer the sheet better, all while being stable at higher speeds. Albany's Microtex 6000 - T579 and the new MicroTex T586 designs provide the better formation, tensiles and stability that are required.
In the press nip, with lower nip loads being used for bulk improvements, dryness becomes a potential issue. The institution of an excess energy surcharge in Europe and the demand for cost improvements overall makes pressing uniformity crucial in maintaining/improving sheet dryness throughout the process. In addition to our energy saving Multiaxial Dynatex/Dynavent styles, Albany is utilizing numerous internal components in a large number of our press fabrics to enhance the micro-pressure distribution levels. Also, new external surface enhancements in our Advantech product line are providing fabrics with surfaces that just a few years ago were unattainable.
ENGINEERING FABRICS TO MEET MORE DEMANDING MARKETS
By Bud Chase, product business leader-forming; Rob Henderson, product manager-press; and Pete McCabe, product manager-forming, AstenJohnson, Charleston, South Carolina
TAD technology allowed tissue papermakers to segment their markets in the premium at home tissue/towel quite a few years ago. TAD technology is now segmenting the away from home (AFH) mid-range towel segment. To remain cost competitive in this emerging segment and to improve cost position in the at home premium segment, papermakers must be very efficient in fiber and energy use.
These cost sensitivities have placed a high demand on both forming fabrics and TAD fabrics. From a forming standpoint, fiber retention and fast drainage are still critical. Optimum formation is critical to keeping TAD drying costs low. In attempts to improve formation on TAD machines, paper machine manufacturers have increased headbox water flow to improve fiber dispersion, resulting in improved formation. This increases the hydraulic demands on the forming fabric used in the high drainage positions. InTegra[R] T triple layer forming technology from AstenJohnson handles the high drainage demands and still provides drainage, retention and formation. In addition to having higher CD stiffness values that assist in handling the higher hydraulic demands, the InTegra T triple layer forming fabric also has longer life potential.
TAD fabrics have always offered the papermaker the opportunity to emboss the sheet with a unique look and functional absorbency properties. This ability is what allowed TAD produced tissue and towel to lead the at home premium grades and is now actively entering the AFH segment. Using TAD technology for AFH products requires extreme focus on energy. AstenJohnson has proprietary technology allowing papermakers to reduce energy costs.
Press fabrics have historically had little impact on the finished product. Their purpose has been to transfer the sheet from the forming section to the Yankee dryer while removing as much moisture as possible in one or two press nips. Energy usage and life were the two main factors for press fabrics. Advancements such as multi-axial weaving used in the Helix[TM] and Pegasus[TM] products from AstenJohnson allow us to customize base weaves and yarns configurations. We are also exploring new types of batt fiber materials and shapes to help maintain the characteristics imparted on the sheet in the forming section.
THE TWO WORLDS OF TISSUE MAKING
By John Bolt, vice president, global tissue technologies, Voith Fabrics
The global tissue market is divided into two basic technologies: TAD and conventional pressing. Each process is different, as are their respective fabric needs. We must address both technology segments in our fabric research and development.
TAD focuses on forming the best possible sheet to optimize product quality. After the sheet is formed, vacuum is applied to raise and control solids going into the dryer section. Voith Fabrics is currently producing tissue forming fabrics with a high fiber support index (FSI) and drainage index (DI). A high FSI is needed to keep the fabric clean, while a high DI promotes good formation. Our fabrics are thin to control solids. We have ongoing development to produce forming fabrics with even higher fiber support and drainage values; we will be introducing these fabrics soon.
In the dryer or TAD section, we have developed a number of TAD fabrics that provide unique molding properties. Unlike a conventional dryer section, hot air is blown through the sheet being supported by the TAD fabric. The sheet then takes on a more three-dimensional structure to enhance softness during drying. Keeping the TAD fabric clean and open is key to maintaining production. We also have ongoing developments around unique materials and coatings that will improve the performance of the TAD fabric to lower operational costs.
Developing pickup fabrics that improve productivity and reduce energy consumption are the main thrust of Voith Fabrics' development efforts for conventional pressing technologies. Voith Fabrics introduced both laminated (Omega[TM]) and high-density structured base constructions (Gamma Plus[TM] and Delta Plus[TM]) several years ago. We also introduced non-woven composite technology designs with the patented Spectra[TM] fabric.
Most recently Voith Fabrics introduced new Vector[R] technology for tissue producers. Vector press fabrics have patented tri-axial technology that produces a smooth pressing surface. This extremely uniform base construction gives better pressing uniformity at the press nip, which improves water removal from the sheet and provides better sheet moisture profiles. It also increases sheet adhesion to the Yankee dryer, which improves heat transfer and results in better drying rates. This combination provides increased productivity for high-quality tissue products with less energy consumption.
IMPROVING SHEET PROPERTIES WITHOUT CAPITAL EXPENDITURE
By Arthur Bullerwell, applications manager-tissue, Weavexx Corp., Wake Forest, North Carolina, USA
The latest clothing technology offers tissue manufacturers the opportunity to improve sheet properties without capital expenditures or changes to furnish and chemistry. Two examples of this technology are the Vantage 16T triple layer tissue forming fabrics and the Huyperpunch-D Millennium tissue felts. The Vantage 16T is a high fiber support, low caliper fabric design with straight through drainage. It offers fine double layer fabrics with improved sheet formation and straight through drainage. Huyperpunch D is the latest in press felt needling technology. It offers a uniform surface to aid in transfer of lightweight sheets from the forming section to the Yankee. Both have allowed papermakers to improve their sheet properties, runnability, and overall machine efficiency.
The Vantage 16T technology has been applied to suction breast roll, twin wire and Crescent former machines where the goal has been to improve sheet softness or tensile properties to allow the manufacture of premium grades. Huyperpunch D technology has been applied where better sheet transfer was needed to improve sheet appearance. By using the Huyperpunch D needling technology, the felt surface was engineered to meet the specific machine requirements.
REDUCING OPERATING COSTS, MAKING BETTER TISSUE
By Larry Parent, manager, process technology, Metso Paper USA, Biddeford, Maine
The most promising technologies are those that allow tissue makers to reduce operating costs and make better product. The trend toward structured tissue produced by the TAD process gives improved softness and absorbency. Additionally, this process also uses less fiber.
Suppliers such as Metso are working to bring the capital cost per ton of smaller installations closer to that of higher capacity, more cost-effective machines. These capital cost reductions can only be achieved by optimizing every area of the machine. In-depth knowledge of the entire TAD process is critical for this type of development.
TAD tissue production is expanding on a global scale because tissue producers using TAD are realizing higher production rates for premium products, lower production costs, superior product qualities, a higher selling price, and the ability to differentiate products in the marketplace. Through constant contact with tissue producers, Metso Paper has identified a strong demand for lower capacity, lower cost TAD machines. This demand is from TAD producers that want to expand into regions that have lower consumption levels and from producers that want to begin TAD production but require a lower capital investment to do so. A smaller TAD will give producers the ability to broaden their TAD markets or to include TAD in their product mix.
Metso's new Advantage Thru-Air[TM] 100 delivers desirable product attributes while also using less energy and at a lower investment cost. It is available in low and ultra low emission versions to have the lowest environmental impact. New air mixing methods yield the best available temperature uniformity while delivering the lowest possible emission levels. Other improvements include better machine access for operators, more available TAD drying on the TAD roll, and a compact design.
REDUCING COSTS, ADDING VALUE, AND DELIVERING QUALITY
By Brad Dolbey, sales and marketing manager, Voith Andritz Tissue, Janesville, Wisconsin
Economy tissue producers, which also include much of the AFH market, are most interested in lowering fiber and energy costs. The use of bagasse, a fiber source available in Mexico and Asia, has gained in popularity for economy tissue production. Larger diameter Yankees and innovative T-Rib Yankee dryers deliver lower energy cost per ton of production.
Because economy tissue grades are commodities, capital cost per ton is vital. Where market demand exists, wider and higher speed machines using technologies such as PrimePickup[TM] and after dryers on wet crepe machines deliver some of the lowest capital cost per ton for new machines. Machines capable of production speeds of 2400 m/min are in development. Economy consumer grades can take advantage of the adjustable shoe on the TissueFlex[TM] press to increase bulk and hand feel without increasing fiber or energy cost, or increase dryness (reduce energy) over a single pressure roll press configuration. Alternatively, the TissueFlex press can produce the same bulk with reduced fiber content.
Mid-range markets usually include branded and private store label products. Producers in this category that are adding value to their products can take advantage of the TissueFlex press to increase bulk and hand feel. The best results with shoe press technology can be achieved with lightweight facial and toilet tissue. With multi-layer headboxes, producers in the mid-range can increase the use of lower cost fiber in the interior layer(s) without affecting consumer perception of end product quality.
Today, TAD and similar machines dominate the premium market in North America, delivering products with increased bulk, absorbency and softness. They are especially suitable for towel grades. TAD machines have made inroads in the premium market in Europe, but not to the extent as in North America. Product consistency is accomplished by automatic dilution control for cross machine basis weight consistency. Automatic steam boxes control cross machine dryness. Newer technologies in reeling involve automatic feedback to primary and secondary arm drives to control the nip pressure and torque. This ensures that bulk created by the machine is retained from the core to the outside diameter of the log. WaterJet full width reel turn-up systems in the heavier weight tissue yield turn-up efficiencies and have greatly reduced the amount of paper slabbed at the core and outer diameter of the log.
WHAT YOU WILL LEARN
* How different technologies enable various tissue market segments.
* Opportunities for reducing operating costs and improving productivity.
* New developments that can enhance competitiveness in various segments.
* "Tissue: a global tour," Solutions!, March 2004, Product Code: 04MARSO28 (Go to www.tappi.org and enter product code in search engine).
* Tissue: Is the glass half empty or half full?, by Shaw Shahery, Solutions!, June 2003, Product Code: 03JUNS034.
* Turning tissue technology into new and improved products, by Jan Bottiglieri, Solutions!, September 2003, :Product Code: 03SEPSO28.
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|Publication:||Solutions - for People, Processes and Paper|
|Date:||Jun 1, 2004|
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