The Specialty Minerals Research Center (SMRC) is a modern facility located on a campus-like setting in Bethlehem, Pennsylvania. It is dedicated entirely to the development of pigments and pigment application technology. The complex occupies 45,000 square feet (4,170 square meters) of laboratory, library and office space and is primarily designed to act as a resource for the paper industry it serves. SMRC specializes in precipitated calcium carbonate (PCC) research and development and maintains unique laboratories specially equipped for surface and colloid science studies: synthesis laboratories for the discovery and scale-up of new materials and processes, and applications laboratories for the end use testing of paper filling and coating pigments. Synthesis laboratories are equipped to conduct small-scale experiments in batch or continuous modes.
SMRC is the technical hub of commercial activities that take place in all regions of the world, particularly in North and South America. The recently completed Asian Technical Center in Suzhou, China will support the technial activities in Asia. The Specialty Minerals European Research Center (SMERC) in Finland will continue to be the hub for technical support of the European paper industry. In addition to supporting regional commercial activities, the scientists at SMRC are Specialty Minerals Inc.’s (SMI’s) main resource for new product and new technology development.
The instrumentation and testing equipment at SMRC is unparalleled for a pigment supplier to the paper industry. For example, one of the main research goals is to control the synthesis, i.e., the size, shape and surface area of various PCC crystals. Controlling these parameters provides a thorough characterization of the pigments and can be used to infer the performance properties that might be expected from papers that incorporate these pigments. Sophisticated instrumentation is used to characterize experimental PCC and other synthetic pigments. An 800 square foot (74 square meter) laboratory houses multiple instruments to characterize particle size and distribution via X-ray sedimentation, surface area via BET nitrogen adsorption, and Hunter color and brightness. In another laboratory, a scanning electron microscope (SEM) provides imaging capability.
In filled papers, manufacturers are primarily concerned with the properties of opacity, strength and bulk. These properties can be balanced, and often one or more can be maximized by proper selection of PCC morphology. In coated papers, brightness and gloss are often paramount and PCC can deliver both. At SMRC, about 2,000 square feet (186 square meters) in three laboratories provides the constant temperature and humidity (CTH) environment (73°F (23°C), 50% Relative Humidity) that is required for the testing of filled, coated and printed paper samples using various standards and protocols. These laboratories are equipped with a full complement of instruments capable of collecting data in accordance with TAPPI (Technical Association of the Pulp and Paper Industry) in North America and ISO (International Standards Organization) in most other countries. Our scientists are able to test paper made by commercial papermakers as well as experimental samples.
One of the three CTH laboratories is devoted to print testing and equipped with Prüfbau* and Nancy Plowman** offset printers, a bench-scale UV Varnish coater, and a bank of commercially available ink jet printers. These can be used to quickly assess the effects of PCC-containing formulations on image quality and print efficiency. When larger scale print testing is required, or if the intended application is rotogravure printing, larger experimental printing presses are used (for example, the press at the Rochester Institute of Technology (RIT) or another university). Commercial print houses are often used to evaluate pilot experimental papers or samples of commercially produced papers at full commercial scale.
At SMRC, filled papers are produced using various devices. Formers are available that use the principle of static drainage, which is efficient and quick, but produces hand sheets with no directional orientation of the fibers. This is often adequate for assessing the effect of fillers on the optical properties of the sheet. The impact of fillers on the directionality that is imparted by the rapidly moving wires of modern high-speed paper machines can be mimicked using turbulent pulse sheet formers and, more recently, with a dynamic sheet former that forms a sheet via a rotating wire drum.
To study the performance of experimental coating formulations using PCC, scientists at SMRC use the cylindrical laboratory coater (CLC) that operates at speeds up to 6,000 feet/minute, which exceeds the rated speed of commercial coaters anywhere in the world. The rheology of single-sided (C1S) or double-sided coatings (C2S) can be studied using the CLC. Coated and uncoated paper can be calendared and print-tested by several different techniques.
From bench-scale experimentation and product development, to applications testing for our customers, or their customers in turn, SMRC is fully integrated to provide state-of-the-art research, development and support. Most importantly, the goal at SMRC is to answer questions, whatever the source. SMI is fully committed to providing the human, financial and physical resources to accomplish this goal as evidenced by a world class laboratory like the SMRC.
* Prüfbau Printability Tester from Dr.- Ing. H. Dürner GmbH
** Nancy Plowman Associates, Inc.
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