Foaming agents are another important weapon in the toolbox of plastics processors. When it comes to plastic additives, blowing or foaming agents are among the most versatile and functional in terms of performance. They can be used for weight reduction, resin usage reduction, improved thermal and acoustic insulation, increased structural strength, reduced warpage, increased production speed, and to minimize sink marks and surface flaws.
Chemical foaming agents can play a key role which enables both commodity and engineering polymers to process more easily and with improved properties for injection molding and extrusion processes. Both additive producers and resin companies have made improvements to their products over the years. Compatibility and chemical reactions with blowing agent by-products are becoming more important considering desired improvements in part weight and impact strength.
Thermoplastics can be foamed in a number of ways to obtain various densities. Generally speaking, a blowing agent is mixed with the polymer melt to obtain a plastic article with reduced density by displacing polymer with gas. Blowing or foaming agents work like a honeycomb. The foaming agent is mixed in and expands as the CO2 gas is released. Air bubbles are created and nitrogen, or a chemical injection, can be added to create voids or air pockets. The melted polymer reduces the weight of the part or hollows out the inside.
Blowing or foaming agents fall into two general classes—physical and chemical. Various gasses and volatile liquids are used as physical blowing agents. Chemical foaming agents (CFAs) can be organic or inorganic compounds that release gasses upon thermal decomposition. CFAs are typically used to create medium- to high-density foams, and are often used in conjunction with physical blowing agents to obtain low-density foams.
Plastics Color Corp. is a highly experienced supplier of colorants, compounds, and additive masterbatches. We can custom formulate a functional additive package to meet the requirements of your application. Need help? Send us your questions at Info@PlasticsColor.com.