Filling, foaming offer options for manufacturers looking to stretch resin

March 24, 2021
Companies that supply fillers and foaming agents can help plastics processors cope with rising resin prices.

By Karen Hanna 

Skyrocketing resin prices are driving demand for a solution proponents say provides addition through subtraction  cost savings, faster cycle times and reduced resin usage, all from augmenting resin with fillers and foaming agents. 

Nick Sotos, president of iD Additives, said his company has been inundated with calls, as resins typically priced in the 50-cents to 60-cents-per-pound range have soared to $1.20 to $1.40, in the wake of power outages that crippled production in Texas in February. 

“I usually tell guys, ‘Look, I can save you money when its priced at 50. Imagine what I can do for you when resin goes up to 90, which invariably it does once a year at least. This isnt the first time. This is the largest spike we've ever seen,” Sotos said.  

According to Esteban Sagel, a principal at Chemical and Polymer Market Consultants, which tracks the materials market, a Gordian knot of interlocking issues, culminating in the winter storm that blasted Texas in February, has created a stranglehold on resin supply. As a result, some resins now cost nearly three times more than they did last year. 

Fillers and foaming agents, like those supplied by iD Additives, can be added as part of the manufacturing process tobe able to make more parts with the
same amount of resin. As an added bonus, the materials lower the viscosity of the melt flow, meaning machines can be operated at lower temperatures and pressures, reducing cycle times and energy consumptionThanks to the enhanced capabilities of newer machines, the range of parts that can be considered for the process is growing.

“Our goal is always 10 percent,” said Ron Bishop, technical manager at iD Additives, in terms of cutting resin use. Cycle times often drop 15 percent. 

Eligible candidates once had to have a minimum wall thickness of 0.19 inchBishop said; now, even parts with wall thicknesses as thin as 0.028 can be filled or foamed — or both.  

It’s come a long way from back in the day. Back in the day, the only thing people wanted to foam was quarter-inch or thicker parts. With our technology, were able to do general applications and, even in blown film, extrusion, we're able to do some amazing [things] ... like a 25-mil sheeand take like 12 percent density out,” Bishop said. 

In a recent video interview with Bishop and SotosBishop sat in front of a poster, illustrating a case study from a couple years ago. At the time of the project, involving the use of foaming agents to produce a shampoo cap, the manufacturer was able to save about $29,000 a year, based on PP prices of about 60 cents a pound. 

“And today, it would be $67,000,” said Greg Hannoosh, president of Next Step Communications Inc., a Kittery PointMainefirm that provides PR services to iD Additives. 

One day before the call, Bishop said he was in Chicago, helping an extrusion blow molder cut its material usage by 15 percent.  

To make the switch, operators only need to adjust their machine settings. For injection molders, the process typically takes less than an hour; extrusion operators require quite a bit longer, Sotos said.  

“You dont have to get a new machine, you don't have to do anything like that. Use the same machine, same mold,” Bishop said. 

Because of the differences in viscosity, once fillers, foaming agents or both
have been added, the melt doesn’t require as much pressure.This means molders don’t need to pack and hold the melt — vexing change for some molders.

“It doesn’t take them long. Some people have a problem with not using pack and hold. I mean, they’ve been taught their whole lives, ‘Got to pack, got to hold.’ Sometimes thats hard for them to wrap their head around that,” Bishop said.  

But once molders have accepted that lesson, filling and foaming is easy, Bishop said. 

“I teach them how to walk; they run,” he said.  

Bishop and Sotos acknowledged that using fillers and foaming agents comes with a potential downside  a slight loss of structural integrity. But, depending on the part and the amount of additives that are used, the impact can be negligible. 

In many cases, users can’t even tell the resin has been cut with fillers or foaming agents, Bishop said. 

“You can put any color you want, hit an 8 percent density reduction, and good luck finding the foam,” said Bishop, as he showed off a part made with foam. “But this is a very, very high-quality, high-gloss surface. And if you put any color in it at all, you never know [the foam’s] there,” he said. 

Karen Hanna, associate editor

[email protected]


Chemical and Polymer Market Consultants, Houston, [email protected] 

iD Additives Inc., La Grange, Ill., 708-588-0081,  

About the Author

Karen Hanna | Senior Staff Reporter

Senior Staff Reporter Karen Hanna covers injection molding, molds and tooling, processors, workforce and other topics, and writes features including In Other Words and Problem Solved for Plastics Machinery & Manufacturing, Plastics Recycling and The Journal of Blow Molding. She has more than 15 years of experience in daily and magazine journalism.