Production of foamed plastics

For the production of foamed plastics two methods can be essentially differentiated. 

What are the trends in the polymeric foam industry The production of foamed plastics on the basis of high polymers will continue to expand mainly utilizing common raw materials (polystyrene, poly(vinyl chloride), polyolefins and synthetic resins). Apart from that, one should expect a strong increase in the commercial pro-... 

General. The production of foamed plastics requires three successive steps liquid state, bubbles of gas, and solidification. The way these three steps are carried out depends upon the type of polymer and the type of foam being produced. 

This phenomenon has implications in the production of foamed plastics wherein a gas, normally nitrogen, is added to pol)miers such as PE, PP and PS during two-phase processing. 

The properties of commercial rigid foamed plastics are presented in Table 2. The properties of commercial flexible foamed plastics are presented in Table 4. The definition of a flexible foamed plastic is that recommended by the ASTM Committee D 11. The data shown demonstrate the broad ranges of properties of commercial products rather than an accurate set of properties on a specific few materials. Specific producers of foamed plastics should be consulted for properties on a particular product (137,138,142). 

Ammonium acetate has limited commercial uses. It serves as an analytical reagent, and in the production of foam mbber and vinyl plastics it is also used as a diaphoretic and diuretic in pharmaceutical appHcations. The salt has some importance as a mordant in textile dyeing. In a hot dye bath, gradual volatilization of ammonia from the ammonium acetate causes the dye solution to become progressively more acidic. This increase in acidity enhances the color and permanence of the dyeing process. 

Chlorofluoro- Used in refrigeration and production of Refrigeration, plastic foam production, Attacks stratospheric ozone layer green-... 

Consider the laboratory reactor system shown in Figure 10-9. This system is designed to react phosgene (COCl2) with aniline to produce isocyanate and HC1. The reaction is shown in Figure 10-10. The isocyanate is used for the production of foams and plastics. 

These routes are at different stages of development. Due to the popularity of the empirical approach, the chemical and technological directions are better developed than the others. Technical characteristics of foamed plastics, which are in many respects unique, determine the rapid development of the applied direction. Physicochemical, physical and construction-materid directions are lagging far behind. However, these are the routes which ultimately provide the scientific foundations for ps-fiUed polymer production. 

This is a bimonthly publication published by Technomic Publishing Co., Inc. at 851 New Holland Avenue, Box 3535, Lancaster, PA 17604. This journal has been published for 24 years and is a major source of information in foamed plastics technology, covering new developments and applications. In addition to articles on product applications and markets there is an index of foamed plastic patents from industrial nations and a section on industry news. 

For any or all of these reasons, foamed plastics are now growing at a much faster rate than the plastics industry as a whole. At the same time, current notions of the basic relationships between foam structure and properties must be refined considerably to facilitate the proper production and use of foamed plastics in an even greater range of applications. 

In recent years there has been activity generally in the production of safe plastic foams and in this connection certain flame retardant phenolic resin foams formulated from resols containing phenolic resin oligomers involving CNSL have been found to be free of harmful gases on combustion (ref. 254). 

Sucrose also has a limited number of industrial applications unrelated to the food industry. It is used in the production of some plastics, such as rigid polyurethane foams, in the manufacture of inks, and in the production of some types of soap. 

Obtained forms of foamed plastics are blocks, sheets, slabs, boards, molded products, and extruded shapes. These plastics can also be sprayed onto substrates to form coatings, foamed in place between walls (i.e., poured into the empty space in liquid form and allowed to foam), or used as a core in mechanical structures. It has also become possible to process foamed plastics by conventional processing machines like extruders and injection-molding machines. 

For on-site production of foam, the raw materials are transported by pumps into a foaming machine. A dispersion of foam stabilizing agent is formed in water in the machine and the resin is introduced into the mixing chamber through jets. The finished foam emerges from the plastic pipe and can be used immediately at the site. One thousand liters (1 m ) of foam can be produced on-site from 20 liters of resin and 18 liters of foam solution. 

Details A liquid, used in the production of PU plastics and foams. 

---