Simple Solutions That Work! Issue 12

Graph 3 – Example of total VOC emis- sions in comparison (OCMA & PCS) *systems tested at 1.3% total binder level and 55/45 Pt1to Pt2 ratio Fig. 1- Smoke comparison between Aro- matic and Silicatic PUCB systems Graph 4 – Bench life properties compar- ison at 42C0 sand temperature (108F0) & 60% Relative Humidity. Binder level 1.5% at 55/45 Pt1 to Pt2 ratio 28 Contact: AYAX RANGEL [email protected] 28 the long term, presently, there are several practical commercially existing solutions that the industry could adopt depending on the specific need or challenge. To begin with, the majority of the PUCB systems out there have reduced the emissions profile by several chemical enhancements such as lower phenol and formaldehyde contents. In addition, depending on the chemical makeup of the resin’s components as well as the solvents being used, there are some important benefits that can assist in mitigating the environmental footprint in the metal casting process. There are PUCB systems that adopted the use of naphthalene depleted solvents that help to reduce BTX (benzene, toluene, and xylene) HAPs. The introduction of renewable products such as biodiesel solvents have also helped to reduce the VOC and HAP profile of the binder system. One of the most innovative solutions is the use of silicatic solvents in the PUCB system. Silicatic solvents are inorganic solvents that show several environmental advantages and are the perfect bridge between PUCB and inorganic systems (IOB). These type of PUCB systems display the lowest smoke and odor profile at the pouring, cooling, and shake out areas in a foundry, they also exhibit one of the lowest VOC profiles when total VOC’s are taken into consideration from core making to pouring, cooling, and shakeout (PCS). Relevant experience gathered in the use of this type of cold box systems have shown low condensates profile. Bench Life This is one of the most important performance attributes the industry considers when selecting a PUCB system. As foundries and TIER suppliers deal with more challenging operational conditions such an extreme heat & humidity, as well as different sources of aggregates for their operations, the capacity of the sand-resin mix to withstand such conditions and produce quality cores, hours after the sand and chemicals are mixed, is paramount for a sustainable core making process. Some of the newer PUCB developments exhibit an extraordinary capacity to maintain a workable bench life under harsh conditions, hence reducing downtime at core making due to aged mixes. Dimensional Tolerances The vast majority of PUCB systems available exhibit a good amount of dimensional tolerances. Yet, as the castings produced become lighter and more complex, the binder system must conform to increasingly higher tolerances. Newer PUCB systems are engineered to assist in minimizing shrinkage defects in light alloys associated with PUCB systems. Productivity This is the main driver of why PUCB became the supreme binder system for high production cores/castings. Often times the gains in curing speed are hampered by lack of wipe-off, release, or similar properties. In recent years innovative PUCB systems have demonstrated significant advances in these characteristics that virtually have reduced the downtime related to wipe- off and/or release to a minimum. SUMMARY PUCB technology has been pushed to the limits to what before was considered not feasible. New advancements in the binder systems had allowed foundries to manufacture cores & molds with methods and materials that just a few years ago would have been considered unsustainable. The PUCB technology has improved its environmental footprint in recent years. Even though the technology is mature, our chemists continue to tweak it in order to reduce the emissions, odor, and smoke. The above examples are only illustrations of the newer technologies available in the North America market. There are other systems designed to address other critical aspects of the PUCB. It is important to consult with your binder supplier for additional information.