Books

Hubbe, M. A., and King, K. (2009). Cost-Saving Strategies in Papermaking Chemistry, TAPPI Press, Atlanta, 237 pp.

Chapter One: Overview

Chapter Two: Losses

Chapter Three: Increased Production

Chapter Four: Decreased Downtime

Chapter Five: Using Functional Additives More Effectively

Chapter Six: Using Process Additives Efficiently and Reducing Variability

Chapter Seven: Making it Possible to Reduce Fiber Costs

Chapter Eight: Energy Issues and Handling Chemical Additives Efficiently

Supplemental information about case studies

FOREWORD

            The authors of this handbook first became involved in the presentation of this subject matter in the form of a two-day TAPPI course.  In our experience, such courses can provide an ideal environment for discussion, answering individual questions, and working in groups on case studies.  We recommend off-site courses as a great opportunity to enrich your skills, make useful contacts, and begin to develop ideas that you can implement once you get back to your worksite.

            But not everyone has the time flexibility or budget opportunities to attend an off-site course. It can be hard to justify time away from the job, even when the training may involve cost-cutting strategies.

            The target audience for this handbook includes two groups:  1) those who read the book on their own, and 2) those who are fortunate enough to participate in a course.  As members of the papermaking community we are proud to uphold a TAPPI tradition of providing technical books.  Books are a time-proven medium for dissemination of helpful information, allowing the reader to study the material at a self-selected rate, while providing the opportunity to skip directly to the subject matter of most interest and importance.  Readers of this handbook should include engineers, scientists, paper mill staff, chemical company technical support representatives, students, and people from other disciplines who are interested in promoting the economic success of papermaking operations. 

            As far as the authors have been able to determine, based on our search of the literature, there has never been a textbook devoted to the cost impacts of papermaking chemical additives.  A lot of articles have been published over the years having to do with economic aspects of papermaking chemistry, but apparently there has been no attempt to gather such material into an organized, relatively concise package.  All subjects are not covered in great detail in this handbook; thus the reader is encouraged to refer to the annotated bibliographies at the end of each chapter for additional resource materials on selected topics.

Hubbe, M. A., and Rosencrance, S. (eds.) (2018). Advances in Papermaking Wet End Chemistry Application Technologies, TAPPI Press, Atlanta, pp. 7-42.

Chapter	Authors	Title
1	Martin A. Hubbe and Scott Rosencrance	Overview
2	Logan Jackson, Junhua Chen, Martin A. Hubbe, and Scott Rosencrance	Handling, dilution, and pumping of papermaking additives
3	Darren K. Swales	Mixology – Theory and practice as applied to papermaking
4	Jari Kayhko, Mouni Matula, Jussi Matula, and Emmi Kallio	Systems for feeding and mixing wet-end additives
5	Kause Dolle and Martin A. Hubbe	Paper machine white-water systems and the paper machine wet end
6	Martin A. Hubbe and Daniel Waetzig	Charge monitoring and control
7	Jukka Nokelainen, Timo Rantala, and Lasse Kauppinen	Control and optimization of retention
8	Martin Hubbe and Klaus Dolle	Drainage strategies and micro- or nanoparticle systems
9	Louis R. Morimanno and Leslie A. McLain	Mineral fillers: Application strategies and value
10	Janet Woodward and Tod Stoner	Microbial control strategies
11	Stephen J.. Broschart	Optimization of dry-strength additives
12	Martin A. Hubbe, John S. Powell, and Greg Delozier	Enzymatic technology for wet-end implementation
13	Przemyslaw Pruszynski and Richard Gratton	Wet-end chemical applications: Paper machine chemical environment and interactions between chemical additives

Chapter 1 – Overview

Martin A. Hubbe and Scott Rosencrance

1-1 Advances in equipment imply new opportunities

Papermaking can be viewed as a process by which a mixture of cellulosic fibers and many other potential components in an aqueous suspension are combined into a sheet, by the removal of water. This definition is as relevant today as it was in the year 105 when Cai Lun, an official in the Han dynasty of China, left the first written account of the papermaking process. What is different today are the speed, sophistication, and automation of the equipment. The purpose of this book is to highlight ways in which recent progress in equipment, automation, and procedures is providing improvements in efficiency and effectiveness of chemical additives used in the papermaking process. Such advances can be keys to achieving advantages of the paper product uniformity and production rates, as well as imparting improved functionality and end-use performance to the resulting paper products.

This book will focus on various devices, procedures, and systems that can improve the performance of chemical additives used during the production of paper, as well as reduce variation in the desired benefits of additives introduced into the process. It is important that engineers engaged in improving the efficiency of operations, as well as the quality and uniformity of the products, have a solid grasp of how these applications technologies work.

The concept of this book grew out of discussions among the instructors of TAPPI’s “Introduction to Wet End Chemistry” 3-day course. Although many excellent articles and trade literature items have dealt with applications technologies for wet-end chemical additives, there appeared to be a need to compile this type of information in a book. Many volunteers have joined together to contribute to this book. The support of the Papermaking Additives Committee of TAPPI has been very helpful. We are indebted to the chapter authors for sharing their expertise as well as the many companies who have encouraged these experts to contribute to the creation of this book.

Especially when discussing equipment, it is important to emphasize that the examples mentioned in this book should not be regarded as endorsements by the authors or editors of any specific brand or source. There are many commercial additives and equipment choices available in the marketplace. These offerings are designed to impart the best possible benefit to the customer process and end product. Innovations related to papermaking chemistry are highly competitive and an area of active investment for suppliers of both chemicals and equipment. Such investments can result in a variety of intellectual property positions, which can include patents. These patents, of course, offer their owners a competitive advantage. Both the supplier and the end user of any additive or equipment are urged to thoroughly understand any relevant patent positions and to ensure that both offerings and usage are fully in compliance with the appropriate laws. Likewise, in some chapters the authors discuss values associated with various regulations that were applicable at the time the chapter was written. Readers are encouraged to verify the latest details relating to any regulatory information contained in this book to ensure accuracy at the time of use.

1-2 Definitions

To begin, some key terms will be defined:

Wet end: The part of a paper machine system in which a suspension of cellulosic fibers is combined with various additives and formed into a sheet with continuous removal of water through one or a pair of fabric screens.

Wet end chemical: An additive to the slurry of cellulosic fibers that has potential to affect the efficiency, reliability, or quality of the process or its products.

Applications technologies for wet end chemistry: The use of equipment and procedures by which a papermaking additive is handled, mixed, or controlled to improve or optimize its performance.

Other terms are defined within the chapters of this book.

1-3 Operational efficiency and product uniformity

Applications technologies can be critical to the economic viability of a papermaking operation. Most paper products today are being sold into highly competitive global markets. Producers of paper-related goods are expected to deliver the most possible tons of stable and reliable product quality while keeping costs as low as possible to maximize profitability.

1-4 Chapter overview

In a general sense, the chapters of the book can be placed into three main groups. Following this introductory chapter, the first five chapters focus on ways in which equipment and procedures are being used to administer papermaking additive systems. The next three chapters focus on control and optimization. The final five chapters deal with aspects of additive performance.

1-4-1 Focus on equipment and basic procedures

Jackson, Chen, Hubbe, and Rosencrance get the book under way with a chapter titled “Handling, dilution, and pumping of papermaking additives.” The chapter covers essential details such as bulk delivery, tote bins, super-sacks, and other options for the receiving and handling of chemical additives at the mill site. The chapter also covers the basics of product handling, inversion of emulsions, preparation of starch for use, and general feeding and pumping topics.

Swales has provided a chapter on the principles of mixing of additives in chests and stock lines. The chapter introduces the term mixology to focus on how concepts such as Reynolds numbers and Newtonian (as well as non-Newtonian) flow can be applied to the resolution of mixing issues. The chapter covers various mixing devices and dilution options, as well as computer simulation of mixing and its visualization.

Käyhkö, Matula, and coauthors follow up with a chapter devoted to advanced injection systems of papermaking additives. They start with a discussion of why the quick and uniform injection of additives can offer advantages to the papermaker. Then they describe velocity-enhancer systems for additive injection. They conclude their chapter with some implementation examples.

Doelle and Hubbe conclude this group with a chapter dealing with paper machine white water system layouts, including some notes about their history. They describe unit operations commonly used in white water systems, with emphasis on the sheet-forming operation and dewatering equipment.

1-4-2 Focus on control and optimization

The part of the book focused on control and optimization starts with a chapter dealing with charge related issues, including a discussion of cationic demand and zeta potential. Hubbe and Waetzig discuss the importance of charge in papermaking operations. Then they describe the most commonly used tests for charge demand and zeta potential or streaming potential, as well as system optimization and control.

Nokelainen, Rantala, and Kauppinen continue the theme of monitoring and control with a chapter on online control of retention aid flows. They start with a discussion of the importance of first-pass retention and reasons to consider its optimization and control. Then they discuss causes of variation. Grade-specific aspects of retention control are considered, as well as some practical results.

Hubbe and Doelle continue with a chapter dealing with the use of drainage-promoting chemicals and strategies. High-charge cationic additives and their effects are considered, as a first main approach. Then they describe the usage of micro- or nanoparticle additives in sequence with the addition of cationic polyelectrolytes, such as cationic acrylamide copolymers or cationic starch.

1-4-3 Focus on additive performance

In the part of the book generally focused on additive performance, McLain and Morimanno start things off with a chapter devoted to the addition and optimization of mineral fillers in the wet end of a paper machine. In addition to a general description of the most-used filler products, they also cover storage and feeding, including the selection of a feed point or multiple feed points. Recent advances include filler flocculation, as well as functionalization of fillers.

Woodward and Stoner continue with a chapter devoted to the application of microbiological control additives. Their topics include safety, a description of different kinds of biocides, and regulatory aspects. Then they describe the designing of a biological control program, as well as monitoring.

Broschart continues with a chapter dealing with strength additives. After describing the general goals of using such additives, he describes the main classes of dry-strength chemicals. Addition strategies covered in the chapter include selection of an addition point, as well as metering and dilution. He also considers logistics for delivery and storage.

Hubbe, Powell, and DeLozier continue with a chapter on the use of enzymes in the paper machine system. They start with a discussion of the many functions of specific enzymes. Certain enzymes have found usage in roles that previously had been the domain of other kinds of chemical additives to the papermaking process. Issues of enzyme sensitivity to temperature and contact time are considered, as well as their gradual loss of activity or purposeful deactivation.

Finally, to bring the book to a close, Pruszynski and Gratton have contributed a chapter on process-chemical factors affecting the performance of various papermaking additives. Such a focus becomes increasingly important in modern papermaking situations where water is reused more times, when there is increasing focus on quality and efficiency, and when there may be frequent grade changes on a paper machine. They share guidelines to help avoid combining additives in an incompatible manner. They discuss potential interactions in terms of chemical interactions, colloidal chemistry, and physical interactions. Examples of incompatibles are discussed, together with available solutions.

1-5 Related reading

Readers who find useful information in this book are encouraged to also consider some related books that have a somewhat different focus, depending on their interests. For example, Smook’s Handbook for Pulp and Paper Technologists (Angus Wilde, 1992) is a classic source for descriptions of the unit operations and related equipment for pulping and papermaking. Likewise, Biermann’s Handbook of Pulping and Papermaking (Academic Press) gives good descriptions of the overall processes and chemistry of pulping and papermaking. Scott’s Principles of Wet End Chemistry (TAPPI Press) is a good starting point for those encountering papermaking chemistries for the first time. Various aspects of the same topic are pursued in greater depth in Neimo’s Papermaking Chemistry in the Papermaking Science and Technology series (Finnish Paper Engineers’ Association and TAPPI) and in Roberts’s The Chemistry of Paper (Royal Society of Chemistry). For a detailed and comprehensive coverage of the chemistry of papermaking additives, Hagiopol and Johnston’s Chemistry of Modern Papermaking (CRC Press) is highly recommended. Hubbe and King’s Cost-Saving Strategies in Papermaking Chemistry (TAPPI Press) covers issues of wet end chemistry as a cost-saving tool.

Hubbe, M. A., and Rosencrance, S. (eds.) (2020). Make Paper Products Stand Out. Strategic Use of Wet End Chemical Additives, TAPPI Press, Atlanta, GA, 285 pp.

Chapter	Authors	Title
1	Martin A. Hubbe and Scott Rosencrance	Introduction: Making your paper special
2	Barbara Lukasik and William Dempsey	Colorants: A way to set your paper product apart
3	Susan Ehrhardt and John Leckey	Fluid resistance: The sizing of paper
4	Franklin Zambrano, Tiago de Assis, Jacob Zwilling, Richard A. Venditti, and Ronalds Gonzalez	Absorbency: Even more attractive toward aqueous liquids
5	D. Steven Keller	Tactile, frictional, and softness attributes of paper: Letting your customer feel your product
6	Martin A. Hubbe	Security papers: Trust but verify
7	Chen Lu, Scott Rosencrance, Darren Swales, Rosy Covarrubias, and Martin A. Hubbe	Dry strength: Strategies for stronger paper
8	Elias Retulainen	Bulky, formable, or foldable paper: Air is the lowest-cost component and a way to reduce basis weight
9	Lokendra Pal, Peeti Tyagi, and Paul D. Fleming	Printing paper: Smooth, possibly glosy, and superior printing

1.4. OVERVIEW OF THIS VOLUME

Chapter 1

Introduction: Making Your Paper Special

Martin A. Hubbe, North Carolina State University, Department of Forest Biomaterials

Scott Rosencrance, Kemira

Chapter 2

Colorants: A Way to Set Your Paper Products Apart

Barbara Lukasik, Kemira

William Dempsey, Kemira

Chapter highlights:

• The human eye perceives color in a complex manner that includes attributes such as hue, chroma, and lightness.
• The L*, a*, b* system provides a convenient way to communicate color specifications and differences relative to standards.
• Direct dyes are the most widely used. Their name implies that they are generally expected to be self-retaining on fibers.
• Carefully organized arrangements of single and double covalent bonds in a dye molecule (conjugation) allows absorbance of visible light.
• Dyes differ with respect to their light fastness, bleed fastness, bleachability, and relative affinity for fibers and other solids in the paper.
• A color-matching problem called metamerism can be expected if a mill is using a red, yellow, or blue dye that is very different in hue from what was used to make the standard for the grade.
• Fluorescent whitening agents (FWAs) work by absorbing ultraviolet light that people cannot see and emitting the energy as blue light.

Chapter 3

Fluid Resistance: The Sizing of Paper

Susan Ehrhardt, Solenis

John Leckey, Solenis

Chapter highlights:

• Papermaking fibers have a natural tendency to take up water. Paper can be made water-resistant by adding internal sizing agents to the fiber suspension or surface sizing agents added at a size press, or both.
• Rosin sizing agents, which mainly fall into the categories of soap sizes and emulsion sizes, are most often used in combination with papermaker’s alum (aluminum sulfate) under acidic papermaking conditions.
• Alkylketene dimer (AKD) and related agents, which are capable of reacting with the hydroxyl groups of fibers, are useful for alkaline papermaking conditions, especially when high levels of holdout are needed.
• Alkenylsuccinic anhydride (ASA) is more reactive than AKD and is recommended when full curing before the size press is desired.
• Styrene maleic anhydride, styrene acrylates, and related copolymers can be added to the size press formulation to increase the hydrophobic character of paper.
• The best sizing strategy is determined by a combination of factors including the reason for sizing, the fiber furnish, other additives, and the equipment available.

Chapter 4

Absorbency: Even More Friendly Toward Aqueous Liquids

Franklin Zambrano Gotera, North Carolina State University, PhD candidate

Tiago de Assis, North Carolina State University (now at Kemira)

Jacob Zwilling, North Carolina State University, PhD candidate

Richard A. Venditti, North Carolina State University

Ronalds Gonzalez, North Carolina State University

Chapter highlights:

• Paper’s ability to absorb moisture is generally favored by high bulk, meaning that the apparent density is low. Papermakers can minimize refining and pressing to keep the paper bulky.
• Creping the paper with a doctor blade, after it has been dried on a large steam-heated cylinder (Yankee), achieves both bulk and absorbency. Chemical additives such as adhesives and release agent can be used to optimize the creping process.
• Fast uptake of fluids is favored by large pores in the paper. However, small pores within the paper can be important if the fluid needs to be held in the paper against gravity or mild pressures.
• There is a need for better testing procedures for reliable assessment of the capacity and rate of liquid uptake by tissue paper and towel products.

Chapter 5

Tactile and Frictional Effects: Soft or Otherwise Distinctive

D. Steven Keller, Miami University, Department of Chemical, Paper and Biomedical Engineering

Chapter highlights:

• Tactile sensations are very important for the perception of quality for both hygienic papers and for flat grades such as printing and writing and premium packaging.
• Objective measurements of softness continue to challenge paper scientists because human tactile sensitivity varies greatly. However, reasonable correlations between instrumental methods and human test panels have helped the papermaker.
• Many techniques for adding value to products by improving perceived softness or handle are available to the papermaker. These include chemicals to change the internal structure, the topography of the surface, or covering the surface with a coating.
• Surface softness, achieved through a reduction of the surface friction with chemical treatments, dominates the perception of softness for both hygienic and flat grade products.

Chapter 6

Security Papers: Trust But Verify

Martin A. Hubbe, North Carolina State University, Department of Forest Biomaterials

Chapter highlights:

• Unique characteristics of currency paper, related to the materials and processes employed, can make it difficult to produce illegal counterfeit paper items.
• Cotton is widely used in currency papers because of its superior strength. To make the paper resistant to water, it is hydrophobically sized and contains wet-strength chemicals.
• Currency often has many security features. The paper can be manufactured with threads, fluorescent items, watermarks, embossing, and specialized high-resolution printing methods to make it recognizable and hard to copy.
• Viable anti-counterfeiting measures tend to be those that are inexpensive to implement on a large scale for continuous centralized production, but which are very difficult or expensive to achieve as an unauthorized copy.

Chapter 7

Dry Strength: Strategies for Stronger Paper

Chen Lu, Kemira

Scott Rosencrance, Kemira

Darren Swales, Kemira

Rosy Covarrubias, Buckman

Martin A. Hubbe, North Carolina State University, Department  of Forest Biomaterials

Chapter highlights:

• In-plane, out-of-plane, and structural mechanical properties are discussed.
• Chemical treatments can increase paper’s strength and are complements to refiner optimization.
• The need for strength additives has been increased because of increased contents of fillers, recycled fibers, and higher-yield pulps.
• The usage of conventional dry-strength additives, which increase the strength of inter-fiber bonding, is discussed.
• Although glyoxylated polyacrylamide was known in the past mainly as a temporary wet-strength agent for tissue and towel grades, this class of chemical has emerged as a promising dry-strength additive.
• Starch, polyvinylamine, and acrylamide-type polymers offer the papermaker a variety of alternatives for increasing paper’s strength.
• Enzymatic technologies in pulp and paper for increasing strength, while being a fairly new technology, have become significantly more common because of  increased levels of application knowledge gained.

Chapter 8

Bulky, Formable, or Foldable Paper: Air Is the Lowest-Cost Component

Elias Retulainen, VTT Technical Research Centre of Finland, Jyväskylä, Finland

Chapter highlights:

• Because air is essentially free, papermakers have a strong incentive to attempt to achieve their product objectives with lower-density sheets.
• Paper’s stiffness can be enhanced if a way is found to increase its bulk while maintaining its elastic modulus.
• Key aspects to optimize are fiber length and stiffness, refining, the nature of cellulosic fines, and addition of micro- or nanocellulose used in the product.
• Wet-end additives can play a key role in maintaining dry strength in bulky paper products.
• Technologies to prepare relief-like contours and three-dimensional paper products can increase their versatility and attractiveness and allow it to compete in certain markets, such as paper plates, trays, and blister packaging, where consumers welcome alternatives to plastic items.
• Three-dimensional forming of paper bowls or containers follows quite different principles and sets different requirements on paper material depending on whether or not the material is held strongly enough on its edges to keep it from slipping during the forming process.

Chapter 9

Printing Paper: Smooth, Possibly Glossy, and Superior Printing

Lokendra Pal, North Carolina State University, Department of Forest Biomaterials

Preeti Tyagi, North Carolina State University, Department of Forest Biomaterials

Paul D. (Dan) Fleming, Western Michigan University, Department of Chemical and Paper Engineering

Chapter highlights:

• Different printing processes place different demands on paper properties. The following types of printing are discussed in this regard: gravure, flexographic, offset lithography, screen printing, electrophotography, and inkjet.
• The different inks used in different printing devices interact with paper in various ways. They also dry differently.
• Print quality can be evaluated in terms of density, show-through, print mottle, print gloss, ink trapping, dot gain, and uniformity, among others.
• Key paper attributes affecting print quality (but highly dependent on the type of printing) include roughness, porosity, optical properties, and moisture content, among others.
• Research progress is being made with respect to the fibers, fillers, wet-end additives, surface sizes, coating, and calendering technologies for printing papers.

Hubbe, M. A., and Rosencrance, S. (eds.) (2022). Process Chemicals for Papermaking, TAPPI Press, Atlanta, GA.

Chapter	Authors	Title
1	Martin A. Hubbe and Scott Rosencrance	Introduction: Why a book about process additives for papermaking
2	Temple Ballard, John Williamson, and William Tuck	Influent water: Starting out with the right waters
3	Martin A. Hubbe	Charge control agents, acids, and basis: Aiming for balanced conditions
4	Robert Wilson and Bree Wittich	Defoamers: Managing air in your process
5	Mel Esmacher, Claudia Pierce, and C. Maltesh	Corrosion control: Maintaining your physical assets
6	Frank Sutman and Mark Nelson	Organic contaminant control: Pitch and stickies
7	M. Angeles Blanco, Ana Balea, Borja Ojembarrena, Daphne Hermosilla, Antonio Gasco, and Carlos Negro	Wastewater treatment: Making sure it ends well

1.1. OVERVIEW

This is a book about process additives and papermaking. Process additives help papermakers achieve the needed levels of efficiency and productivity. Key topics covered in this book include influent water treatment, charge control agents, acids and bases, defoamers, corrosion control, organic deposit control, and effluent water treatment.