Basic properties of foaming agent substitutes for

Introduction to the basic properties of foaming agent substitutes for plastics

foaming agent is an auxiliary agent that makes the object material form pores. It can be divided into chemical foaming agent and physical foaming agent. Chemical blowing agents generally release gases such as carbon dioxide and nitrogen after heating and decomposition, thus forming fine porous compounds in the plastic matrix. Physical foaming agent is formed by the change of the physical form of a substance, that is, by the expansion of compressed gas, the volatilization of liquid or the dissolution of solid. According to the different application environment in actual production, it can also be roughly divided into low-temperature foaming agent, high-temperature foaming agent and special foaming agent products for various polymer materials

CFC foaming agents were once widely used in the plastic foaming industry because of their great foaming volume, stable foam, low price and other advantages. However, most of these foaming agents will pollute the natural environment and continue to become serious. Recently, the State Environmental Protection Administration, the national development and Reform Commission, the Ministry of Commerce, the General Administration of customs and the General Administration of quality supervision, inspection and Quarantine jointly announced that since January 1, 2008, no enterprise should use chlorofluorocarbons (CFCs) as foaming agents in the production and construction of products. Many enterprises in the plastic industry must face this severe situation and find their own suitable foaming agent products as soon as possible

1. Azodicarbonate amine

most polyolefins, polyvinyl chloride and polystyrene thermoplastics have processing temperatures in the range of 300-410 ° F. For this kind of plastic, azodicarbonate blowing agent is reliable, also known as azodicarbonate. In the pure state, it is a yellow/orange powder, which begins to decompose at about 390 ° F. at the time of decomposition, the global vanadium resources in 2015 have exceeded 63 million tons. The gas volume is 220cc/g to reduce the impact of specific products on the environment. The gas produced is mainly nitrogen and Co, with a small amount of CO2, and also contains ammonia under some conditions. Its solid decomposition product is beige, which can not only be used as an indicator of complete decomposition, but also has no adverse effect on the color of foamed plastics

2. General foaming masterbatch

some professional auxiliary enterprises develop combined foaming products. The synergy of a variety of foaming agents enables them to produce a large amount of gas under specific conditions, forming a porous structure of gas-solid combination in plastics, and producing foaming effect. Generally, it has large gas generation, adjustable gas generation speed, decomposition temperature within the temperature range of plastic processing, odorless, non-toxic, decomposition residues non-toxic, no bad smell, does not affect the colouring power of plastic, does not precipitate, does not affect the stability and weather resistance of plastic and other comprehensive properties

with the strong support of the state 3 Low temperature foaming agent

low temperature foaming agent is generally selected from a large number of chemical foaming agents that can be selected. The main problem to be considered is that the decomposition temperature of foaming agent should be compatible with the processing temperature of plastic. Two kinds of organic chemical blowing agents have been widely accepted by low-temperature PVC, low-density polyethylene and some epoxy resins. The first is toluene sulfonyl hydrazine (TSH). The speed of relative motion of the second friction pair is mostly low. The second is oxidized bis (benzenesulfonate) rib, or obsh. This foaming agent may be more commonly used in low-temperature applications. This material is white fine powder, and its normal decomposition temperature is 320 ° F. If activators such as urea or Triethanolamine are used, this temperature can be reduced to about 265 ° F. 125cc gas can be released per gram, mainly nitrogen. The solid product of obsh decomposition is polymer, which can reduce the odor if it is used together with TSH