Chemical blowing agents play an indispensable role in the vast field of modern industrial production. Whether it is the lightweight manufacturing of plastic sheets and pipes, or the elastic molding of rubber shoe soles and seals, chemical blowing agents are indispensable. AC blowing agents and OBSH blowing agents are two of the most commonly used chemical blowing agents in the industry, and each has unique properties and applications.
AC Foaming Agent, chemically known as azodicarbonamide, contains an azo group in its chemical structure, which enables it to decompose and release gases when exposed to heat. In terms of physical appearance, AC blowing agent is usually a light yellow powder, odorless and non-toxic (within reasonable limits of use), with a density of about 1.65 g/cm³, and has good dispersibility and flowability, which facilitates uniform mixing with other raw materials in the production process.
The production process of AC Foaming Agent is mainly based on urea and hydrazine hydrate as the main raw materials, which are produced through a series of chemical reactions such as condensation and oxidation under specific reaction conditions. The quality of the raw materials and the precise control of the reaction conditions directly affect the quality and performance of the AC blowing agent.
OBSH foaming agent, the full name of which is 4,4'-oxobiphenylsulfonylhydrazine, contains sulfonylhydrazine group in its chemical structure, which is the key to its foaming effect.OBSH foaming agent is generally a white powder with a melting point of 150-165°C, and its thermal stability is relatively good as compared to that of AC foaming agent.
In terms of production, OBSH blowing agents are usually prepared by a series of complex organic synthesis reactions using benzenesulfonyl chloride and other raw materials. The production process requires high technological requirements, and parameters such as reaction temperature and time need to be strictly controlled to ensure the stability of product quality.
The decomposition temperature of AC blowing agents generally ranges from 160 - 220°C, which is relatively wide. This characteristic gives AC blowing agents an advantage in production processes that require a wide range of processing temperatures, such as foam molding of common plastic sheets, where stable foaming can be achieved over a wide temperature range. However, the wide range of decomposition temperatures also means that it is difficult to precisely control the foaming time and effect.
The decomposition temperature of OBSH blowing agents is relatively concentrated, usually in the range of 130 - 160°C. This low and concentrated decomposition temperature allows it to perform well in temperature sensitive processes where rapid foaming is required. For example, in the production of certain rubber products, it can decompose quickly to produce gas, which meets the needs of rapid molding, and also facilitates the temperature control in the production process.
AC blowing agents have a high outgassing capacity, generally in the range of 200 - 300 ml/g (under standard conditions). The high outgassing capacity enables it to form more air holes in the products, which reduces the density of the products and improves the light weight of the products. For example, in the foaming of plastic pipes, the use of AC blowing agent can effectively reduce the weight of pipes while maintaining good mechanical properties.
OBSH blowing agent has a relatively low outgassing capacity of about 120 - 160 ml/g (under standard conditions). Although the outgassing volume is not as high as that of AC blowing agent, OBSH blowing agent has a unique advantage in applications where the porosity requirement is not as high and where the fineness and surface quality of the product is more important. For example, in the manufacture of high-grade rubber shoe soles, the lower outgassing volume helps to form a uniform and fine pore structure, which enhances the comfort and aesthetics of the shoe soles.
When AC blowing agent decomposes, it mainly produces gases such as nitrogen, carbon monoxide, carbon dioxide, and a small amount of solid residue. Among them, carbon monoxide has a certain degree of toxicity, so it is necessary to pay attention to ventilation and other safety measures during the production process. These decomposition products may affect the performance of the product, for example, the presence of nitrogen helps to improve the chemical stability of the product, while the solid residue may have a certain effect on the appearance and internal quality of the product.
The gases produced by the decomposition of OBSH blowing agents are mainly nitrogen, with small amounts of water vapor and other small organic molecules. Since the decomposition product is mainly nitrogen, OBSH blowing agent is relatively more advantageous in terms of environmental friendliness and impact on product properties. Nitrogen is an inert gas that does not react chemically with the product, which helps to stabilize the performance of the product and also reduces the pollution of the environment.
In the plastics industry, AC blowing agent is widely used in the foaming production of plastic plates, pipes, sheets and other products by virtue of its high dispersibility and wide range of decomposition temperature. For example, in the production of polystyrene foam sheets, AC blowing agent can decompose rapidly during the extrusion process, generating a large amount of gas and forming a uniform pore structure, which provides the sheets with good thermal insulation, heat insulation and cushioning properties.
OBSH blowing agent is mainly used in the plastics industry in scenarios where the quality of the products is high and the processing temperature is relatively low. For example, in the production of PVC soft foam products, the lower decomposition temperature of OBSH blowing agent can avoid the decomposition of PVC at high temperatures to produce harmful substances, and at the same time, its stable foaming performance can help to improve the surface finish and feel of the products.
In the rubber industry, AC blowing agent is commonly used in the production of ordinary rubber foaming products, such as rubber sponge, rubber sealing strip, etc. It can make the rubber products obtain a larger size. It can make the rubber products obtain larger foaming multiplication, reduce the density of the products, and improve the softness and elasticity of the products. However, due to the small amount of harmful substances contained in the decomposition products of AC blowing agent, it is limited in the application of some high-end rubber products.
OBSH blowing agent shows unique advantages in the field of high-end rubber products. In the manufacture of rubber seals for automobiles, high-grade rubber shoe soles and other products, the environmental friendliness and stable foaming performance of the decomposition products of OBSH blowing agent can ensure that the products have excellent physical properties and good appearance quality, which can satisfy the stringent requirements of the high-end market for product quality.
