The use of chemical foaming agents, such as certain grades of Bergen International’s Foamazol™ Chemical Foaming Agents, can be very affective in sink mark removal in injection molded parts.

Foamazol™ 62 is specifically designed to be used in high pressure injection molding machines to remove sink marks without causing the typical swirling on the surface of foam molded parts. The end result is a product with a Class A surface.

Swirled surface on plastic part
in application where surface appearance is not critical.

Class A surface with no swirling or sink marks.

Various caps foamed with Foamazol™ 62

Advantages to using Foamazol™ 62 in Injection Molding include:

• Foamazol™ 62 can be added like any other additive to the process such as color, UV, etc.

• Shorter cooling times are required with Foamazol™ 62 resulting in faster overall cycle times.

• No post pressure is required after the shot when processing with Foamazol™ 62.

There are many factors involved in good sink mark reduction such as proper mold design and proper selection of a Chemical Foaming Agent. Following these guidelines can further improve sink mark reduction when using Foamazol™ 62 on a high pressure injection molding machine:

• Use a low enough temperature in the feeding section to prevent pre-foaming.

• Use a high enough temperature in the compression zone to provide optimum gas yield.

• Use a shut of nozzle or an injection point adjacent to the mold if possible.

• Use a high enough injection rate to ensure proper gas dispersion and expansion after the injection shot is complete.

For a PDF file on Foamazol™ 62 please click here.
More information on processing with Foamazol™ Chemical Foaming Agents in Injection Molding and other processes can be found here.

The injection molding of structural foam molded parts is a well-established process in the
plastics industry.

There are a number of processes used for the production of rigid, lightweight structural foam moldings. 

Advantages to using Foamazol™ in Structural Foam Molding include:

Bergen International’s line of Foamazol™ Chemical Foaming Agents provides structural foam molders many cost saving benefits.

• Faster Cycle Times – Up to 30% Cycle Reductions

• Excellent Nucleation for Better Control of Cell Size, Distribution and Consistent Density

• Less Nitrogen Usage and Lower Processing Pressures Required

• Smoother Surfaces/Reduced Elephant Skin

More information on processing with Foamazol™ Chemical Foaming Agents in Structual Foam and other processes can be found here.

Bergen International also has a great depth of experience to assist you on developing the best product for your specific needs. Foamazol™ Chemical Foaming Agents offer molders:

• Products for Virtually any Thermoplastics

• Products for Injection Molding, Direct Gas and Chemical Extrusion, Wood-Plastics Composites, Rotational Molding, Wire & Cable …

• Custom Formulations