The development direction of organic binder technology emphasizes the improvement and improvement of performance, and pays more attention to environmental protection technical indicators. The inorganic binder system is still based on the development of silicates, supplemented by organic and inorganic salts. Casting organic binders and inorganic binders are two important types of sand (core) bonding systems. The source of its technology was developed in Europe and the United States in the 1950s and 1960s, and CO 2 hardened water glass sand appeared earlier. The exploration of the hardening mechanism of the new binder system and the improvement of the application performance of the existing products have become a non-stop work, especially whether the inorganic binder can have the performance of the organic binder on the molding sand, and the breakthrough of the inorganic binder becomes An eternal expectation. Combining with the author's experience in modeling materials for nearly 30 years, the following is a brief introduction to the advantages and disadvantages of the two major bonding systems of organic/inorganic binders, and shared with industry colleagues. Organic binder (1) Advantages In chemistry, structure determines the nature of a substance. The organic binder contains carbon elements, and the carbons may be bonded to each other to form a polymer. The organic binder imparts many advantages to the core during casting. 1) Good core strength. 2) High production efficiency. 3) Good casting surface quality and dimensional accuracy. 4) Excellent sand falling performance. 5) Higher old sand recycling rate. (2) Disadvantages Of course, since the material itself is organic, there are some disadvantages as follows. 1) Raw materials are derived from petroleum products or agricultural chemicals. 2) Product prices continue to rise. 3) When modeling and core making, the VOC value is high, which is harmful to the health of the operator. 4) During the pouring process, a large amount of harmful gases are generated and pollute the environment. 2. Inorganic binder: (1) Advantages The inorganic binder constituent elements are sodium, potassium, magnesium, calcium, aluminum, silicon and phosphorus, and the compounds thereof are generally silicates, phosphates and aluminates. Inorganic binders are usually bonded together by dewatering, but this depends on the rate of evaporation of moisture. Due to this characteristic, it has the following advantages. 1) Inorganic binders are widely available and raw materials are inexpensive. 2) The inorganic binder has no solvent evaporation problem. 3) Inorganic binders are produced without harmful gases when casting castings. (2) Disadvantages Water-based inorganic binders generally cure at a slow rate, which is related to the rate of moisture migration. The inorganic binder reacts with the silica sand to form a low melting point. These all make the inorganic binder exhibit the following disadvantages on the molding sand. 1) The hardening speed is slow and the core strength is low. 2) Performance is very sensitive to humidity in the environment. 3) Poor collapsibility. 4) The old sand recycling rate is low. The choice of casting binder determines the casting process. The choice of binder type is very important. It not only determines the investment in the fixed layout of the production workshop, the tooling mold, the molding core equipment, the old sand recycling equipment and the cleaning equipment, but also determines the production process, production cost, Management factors, worker proficiency and market position of products, and many other factors. The choice of binder type is closely related to the type of casting, past habits and experience, local raw material prices and sources. The choice of binder type generally focuses on the technical feasibility of this binder in the future, the economic feasibility, the feasibility of environmental protection, and the feasibility of energy saving and recycling. At present, China can produce various types of self-hardening sand binders with high technical level and all localization. It is an indisputable fact that the production of single-piece small-volume cast iron parts and the production of furan resin sand are ideal processes. Although furan resin prices have risen in recent years, furan resin sands are the lowest compared to other types of hard resin sands. Therefore, in China, furan resin is still the first choice for cast iron resin sand process for a long time in the future. In the production of steel castings, the use of alkaline phenolic resin, nitrogen-free furan resin, especially heat-resistant furan resin, ester-hardened water glass sand has become the consensus of the casting industry. The development of alkaline phenolic resin and ester hardened water glass with high regeneration rate of old sand and regeneration equipment is the key to break through the application of self-hardening sand for cast steel. Our range of Kitchen taps and Sink Mixers are available in a gorgeous choice of designs. Choose from a range of contemporary or traditional Sink Mixer Taps or Kitchen Sink Mixer. For the ultimate flexibility, also take a look at our range of Kitchen Sink Mixers. 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Liu Wei, Director of Jinan Shengquan Group New Materials Technology Research Institute First, the advantages and disadvantages of organic / inorganic binder
Second, the application status of organic / inorganic binders in China
