Development of Screenable Pressure Sensitive Adhesives (original) (raw)
Related papers
Properties of pressure sensitive adhesives found in paper recycling operations
2006
Hot-melt and water-based adhesives are very different materials with similar physical properties. Their ability ct as adhesives is due to physical bonds and mechanical interlocks which form dhesive flows into topographical features on the substrate surface. Hot-melt adhesives are based on soft, rubbery polymers while water-based adhesives are usually acrylic latex emulsions. Both of these materials are soft and weak resulting in adhesive fragmentation during repulping. We have previously successfully modeled the behavior of hot-melts. The formulation and structure of water-based adhesives make them more susceptible to moisture when in storage, in use and in the recycling process, and thus, understanding their behavior is more difficult. Several experimental techniques have been developed to test how moisture is absorbed by adhesive and what effect water n the performance of an adhesive material.
Industrial & Engineering Chemistry Research, 2008
Pressure-sensitive adhesives (PSAs) in recovered paper reduce efficiency and increase operating costs for paper recycling mills. Increased PSA fragmentation during pulping and the corresponding reduction in screening efficiency are indications that a PSA will likely interfere with paper recycling. Water-based PSAs, which dominate the label market, have complex formulations that include several amphiphilic materials, i.e., emulsifiers, dispersants, and wetting agents. Increasing the amount of these surface-active materials increased adhesive fragmentation during pulping, and thus reduced screening removal efficiencies. Accompanying the reduction in size was a distinct change in morphology of adhesive particles, which assumed a less collapsed structure during repulping. The presence of surface-active materials also appeared to facilitate the removal of fiber from PSA films during repulping, reducing the importance of paper facestock properties in determining fragmentation behavior. The findings presented here combined with results reported previously provide more complete guidelines for the synthesis and formulation of recycling-compatible acrylic water-based PSAs.
Design Criteria for Recycling Compatible Pressure-Sensitive Products
Pressure sensitive adhesive (PSA) contaminates post consumer waste impeding its processing and limiting the use of recovered cellulose fiber. An approach for reducing the impact of PSA on recycling operations is to redesign label systems to inhibit fragmentation of adhesive films. This results in residual PSA particles that are more easily removed from the process with conventional mill contaminant control equipment. In this presentation findings are reviewed from research aimed at the development of adhesive films that have little or no negative impact on recycling operations. Both hot-melt and waterbased formulations were examined, which combined, account for much of the PSA paper label market. For both types of PSAs, properties of the base polymer or polymer blend govern, to a great extent, fragmentation behavior during processing, but via very different mechanisms. Also discussed will be the role of laminate design and processing aids in determining the fragmentation behavior of adhesive films.
Journal of Applied Polymer Science, 2003
Pressure-sensitive adhesives (PSAs) have long been a problem as sticky contaminants for paper recycling mills. The main problem associated with such stickies is that the PSAs in the waste papers deposit on the felts, press rolls, and drying cylinders of paper machines, and this creates problems with paper formation, reducing the paper quality and paper machine runnability. The annual cost of stickies to the U.S. paper industry is estimated to be about $600,000,000-650,000,000. To solve this problem, a series of cationic water-soluble/dispersible PSAs have been synthesized by the free-radical solution polymerization of butyl acrylate and [3-(methacryloylamino)propyl]trimethylammonium chloride in ethanol. The PSA end-use properties, repulpability in paper recycling, and the effects on the properties of recycled paper products have been studied. The cationic PSAs can be dissolved or dispersed in water if the cationic charge density in the PSA backbone is controlled, and so they do not deposit as stickies during recycling and papermaking processes. Because the PSAs are cationically charged, they can easily be removed from the papermaking system by adsorption onto the negatively charged fibers and fine surfaces. Furthermore, the adsorbed colloidal or dissolved PSAs have little effect on the final paper properties.
A Pilot Plant Study of the Recyclability of Pressure Sensitive Adhesives (Psa)
1998
This paper discusses the operation and results obtained from a pilot plant study of the recyclability of post consumer pressure sensitive adhesive (PSA) postage stamp material. The trial work was carried out in May of 1999 at the Beloit Pulping Pilot Plant in Pittsfield MA., in cooperation with the U.S. Postal Service, and the U.S.D.A. Forest Products Lab in Madison WI. This work is a part of a much larger USPS development program currently under way with the main objective being “to develop postage stamps that do not adversely affect the environment”. The goal of the project is to develop a PSA material which can be successfully recycled in the typical mixed office waste (MOW) deinking system producing a pulp for inclusion in printing and writing grades. This trial looks at a “new generation” PSA developed specifically to improve its recyclability when compared to the products in current use by the Postal Service. The adhesive supplied for these trials breaks down in the pulping pr...
Recycling Pressure-Sensitive Products
2012
The efficient control of contaminants such as metals, plastics, inks and adhesives during the processing of recovered paper products determines the profitability of recycling mills. In fact, it is arguably the most important technical obstacle in expanding the use of recycled paper.1-4 An especially challenging category of contaminants to manage is pressure-sensitive adhesive (PSA). PSAs are soft elastomer-based materials that are highly viscous and sticky to the touch. In recovered paper, they are usually found as part of pressure-sensitive (PS) label systems, consisting of facestock coated with a 0.7-1.0 mil layer of PSA.
October 2016 TAPPI JOURNAL, 2016
This study investigated the addition of acrylic fiber to old corrugated container (OCC) pulp as a possible means of overcoming adverse effects of water-based pressure sensitive adhesives during manufacture of paper or paperboard. Such adhesives can constitute a main source of stickies, which hurt the efficiency of the papermaking process and make tacky spots in the product. The highest amount of acrylic fiber added to recycled pulps generally resulted in a 77% reduction in accepted pulp microstickies. The addition of acrylic fibers also increased pulp freeness, tear index, burst strength, and breaking length, though there was a reduction in screen yield. Hence, in addition to controlling the adverse effects of stickies, the addition of acrylic fibers resulted in the improvement of the mechanical properties of paper compared with a control sample.