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Novel test method for measuring defects in barrier coatings, TAPPI Journal November 2022
ABSTRACT: In the last several years, activity to develop water-based barrier coatings (WBBCs) that meet challenging packaging performance requirements has increased dramatically. Cellulose-based packaging solutions can provide a more sustainable packaging option for replacing single-use plastic-based options like extrusion-based and laminated materials. An advantage of WBBCs is the opportunity to reduce the coating thickness applied, as long as the barrier requirements can be met. A challenge that must be overcome is the ability to maintain a defect and pin-hole-free coating layer after coating and drying to retain the barrier performance. Many formulation and coating parameters can affect the barrier coating layer quality; however, methods for detecting more subtle differences in these types of studies are not widely available. Work was carried out to develop a quantitative technique for detecting and measuring the quantity and size of defects in the barrier coating layer. A test method has been developed using a combination of dyed oil and image analysis to be able to characterize the imperfections in the coating surface. The use of dyed oil serves two purposes. First, it better simulates the types of materials, in this case, oils and grease, for which the barrier coating is expected to hold out. Second, it also provides contrast between the coating and failure points for testing. An image analysis technique is employed to characterize the number and size of the imperfections. For the former, it reduces the testing time required if a quality control or laboratory technician counts the dots. For the latter, it assists with judgment on the source of the root cause of the imperfection, such as base sheet defects, coating dispersion issues, or perhaps micro-blisters in the coating, as some examples.To show the benefit of this technique, several pilot coating studies were designed to see if the new technique could be utilized to detect differences in WBBC performance. Both process and chemical variables were evaluated. With refinement, it is believed this technique can be utilized in development work, as well as for a potential quality control technique for manufacturing of coated paper and paperboard products.
Journal articles
Magazine articles
The Mechanism of Bonding, TAPPI Journal September 2022
ABSTRACT: Three factors are involved in cellulose bonding--available area, contact, and hydrogen bonding.
Journal articles
Magazine articles
Black liquor evaporators upgrade — How many effects?, TAPPI Journal April 2023
ABSTRACT: Black liquor evaporation is generally the most energy intensive unit operation in a pulp and paper manufacturing facility. The black liquor evaporators can represent a third or more of the total mill steam usage, followed by the paper machine and digester. When considering an evaporator rebuild or a new system, the key design question is how many effects to include in the system. The number of effects is the main design feature that deter-mines the economy of the system and the steam usage for a given evaporation capacity. A higher number of effects increases steam economy and reduces energy cost to a point, but additional effects also have higher initial capital cost and increased power costs. This research paper uses life-cycle cost analysis (LCCA) as a method to determine the optimum number of evaporator effects for a new evaporator system. The same basic principles and method can also apply to existing evaporator rebuild projects.
Magazine articles
Slotted headbx screening for fine, publication, and newsprint grades, TAPPI JOURNAL, April 1990, Vol. 73(4)
Slotted headbx screening for fine, publication, and newsprint grades, TAPPI JOURNAL, April 1990, Vol. 73(4)
Magazine articles
Highly alloyed stainless steels to cope with corrosion, TAPPI JOURNAL, December 1990, Vol. 73(12)
Highly alloyed stainless steels to cope with corrosion, TAPPI JOURNAL, December 1990, Vol. 73(12)
Magazine articles
Chemically structured kaolin: a new coating pigment, TAPPI JOURNAL, February 1990, Vol. 73(2)
Chemically structured kaolin: a new coating pigment, TAPPI JOURNAL, February 1990, Vol. 73(2)
Magazine articles
Pump bearings: a new bearing system to improve reliability, TAPPI JOURNAL, March 1990, Vol. 73(3)
Pump bearings: a new bearing system to improve reliability, TAPPI JOURNAL, March 1990, Vol. 73(3)
Magazine articles
Steam cycle passivation and corrosion protection, TAPPI JOURNAL, March 1990, Vol. 73(3)
Steam cycle passivation and corrosion protection, TAPPI JOURNAL, March 1990, Vol. 73(3)
Magazine articles
Measuring customer perception of print quality, TAPPI JOURNAL, March 1990, Vol. 73(3)
Measuring customer perception of print quality, TAPPI JOURNAL, March 1990, Vol. 73(3)
Magazine articles
The behavior-based approach to safety: a clear picture, an effective plan, TAPPI JOURNAL, August 1991, Vol. 74(8)
The behavior-based approach to safety: a clear picture, an effective plan, TAPPI JOURNAL, August 1991, Vol. 74(8)