Epoxy Resin as Undercut Filler for Steel Drums Yang Yanchang In addition to seam welding, the bottom cover of both ends of the oil drum is flattened using multiple layers of undercuts (Fig. 1). Some products, however, feature a lighter undercut that is not fully flattened, known as a "round curl" (Fig. 2). Whether the undercut is flattened or left as a round curl, it is essential to apply a layer of traditional brown sugar bone glue before the undercut process. This step ensures that the oil drum remains leak-proof after molding. Figure 1: Flattening the Curls Figure 2: Round Curl In recent years, there has been a growing emphasis on product quality and durability, especially in packaging containers. The appearance and performance are now key factors in evaluating the overall quality of the product. While minor leaks may be acceptable during short-distance transportation, they become unacceptable for long-distance shipping or storage. Leaks can lead to serious issues such as corrosion from toxic chemicals or even fires caused by flammable solvents. As a result, leakage has become one of the top quality concerns in the barrel industry. Previously, we tried replacing the traditional red gutta percha filler with Tianjin Latex and Xiamen-made latex, but this still resulted in about 10% of leaks. For sensitive chemical products like ethanolamine or formaldehyde, these materials were almost ineffective. These substances are highly corrosive and expensive, making it crucial to ensure no leakage occurs. To address these challenges, we developed an epoxy resin-based formula. It includes dibutyl phthalate as a toughening agent, ethylenediamine as a curing agent, anhydrous ethanol as a diluent, and talc as a filler. This formulation proved highly effective as an undercut filler, achieving a 100% qualification rate. It successfully solved the long-standing issue of chronic oil leakage in steel drums. We have tested and applied this epoxy resin formula as a filler in oil drums. Even after aging and wear, the epoxy resin at the undercut remained firmly bonded to the metal sheets, preventing any leakage. The principle behind this lies in the molecular structure of epoxy resins, which contain hydroxyl groups, ether groups, and highly reactive epoxy groups. These functional groups create strong adhesion between the resin and the surrounding material. Epoxy resin is a thermosetting polymer that forms a cross-linked network when cured. This structure gives it excellent chemical stability, mechanical strength, and resistance to shrinkage, deformation, heat, water, acids, alkalis, and chemical corrosion. Therefore, it is ideal for storing and transporting hazardous chemical products without the risk of leakage. Whitening face wash facial cleanser,Foam fine facial cleanser,Hydrating facial cleanser,Cleansing gel facial cleanser HomeSafe Group , https://www.homesafebio.com
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