Who wants plastic scrap? Recycling and the issue of material compatibility

By: 
December 15, 2015


With the continuing drop in crude oil prices and natural gas, virgin plastic prices are also decreasing. While that bodes well for plastics processors, whose customers need 100% virgin materials, it's not such a good thing for the recycled plastics producers. Recycled plastics are in high demand when virgin resin prices are high because adding a certain amount of regrind to the virgin material can help reduce the cost of the parts. And as everyone knows, price is one of the most important factors in this game of manufacturing.

plastic bottleI can remember talking to thermoformers at the SPE Thermoforming Division conference a few years ago when recycled PET (rPET) was in big demand and in short supply, because the price of virgin PET was up there. With the price of virgin PET dropping, thermoformers at this year's SPE Thermoforming conference told me that demand for rPET was down. "What's the point in buying recycled PET when you can get virgin for virtually the same price?" one thermoforming guy told me.

Yet the recycling issue continues to hold a place in the industry and in the mind of the consumer. Pedro Morales, Director of Sales and Marketing, Recycling Div., KW Plastics (Troy, AL), told attendees at the Global Plastics Summit this past October that "we all have to be concerned about public opinion. It's clear that all of our activities are in the public opinion polls."

KW Plastics' five facilities process "millions of pounds of feedstock" from across the United States, which helps extend the life of landfills, and is successfully recycling HDPE (#2) and PP (#5). In 2012, KW processed 1,045,400,000 pounds of HDPE, 31.6% of virgin HDPE consumption. For non-bottle regrind, the company processed 357.4 million pounds. In PP, the company processed 62,000,000 pounds of bottles, or 31.8% of virgin PP consumption. KW processed a total of 1.5 billion pounds annually in 2013 year of postconsumer recyclate.

Morales explained the difference between "reprocessed" plastic and "postconsumer" reclyclate. "Reprocessed thermoplastic material is from scrap or rejected parts within a molding facility and doesn't change ownership," he said. "Postconsumer—the arena in which KW participates—is material that has been used for its intended purpose and is subject to disposal but is diverted from the landfill, and ownership of the material changes."

Morales said that KW has seen record commodity prices over the last six to seven years, and the company has "provided municipalities with recovery funds" for its diversion of postconsumer scrap from landfills. He explained that the cost to separate and bale postconsumer plastic scrap is seven cents a pound and there are 1,000 pounds to a bale. "The waste industry is looking at the least expensive way to collect and sort—a method that reduces yield but results in good material," he said.

There are several factors that affect the price of postconsumer scrap material:

  • The price of virgin—scrap pricing usually follows the virgin resin industry;
  • The weather—KW lost 24% of material in the first quarter of 2015 because of weather;
  • Global markets—China is a big importer of scrap;
  • Legislation, politics and consumer attitudes;
  • The absence of a reliable index for postconsumer scrap.

Morales said that postconsumer recyclate quality has "improved tremendously." So far in 2015, the company has had only 10 serious complaints, which is "way down," and the company meets all regulatory requirements. In 2014, KY Plastics received "expanded approval" from the U.S. Food and Drug Administration's Center of Food Safety and Applied Nutrition for KWR621 FDA, a food-grade PP. The material has been approved for levels up to 100% recycled content.

"With an increase in capacity, we should see an increase in recycling, as materials will continue to be diverted from the landfill, even as the delta is a lot smaller between virgin and postconsumer recyclate," said Morales. "There has to be green in green efforts, or it won't work. It takes a lot of green to stay in the black."

Reducing the costs and carbon footprint of recycling would seem to be insurmountable challenges, but there are answers on the horizon. Would recycling be more cost effective if there was a way to eliminate the sorting and recycle co-mingled plastics? Salvatore Monte, president of Kenrich Petrochemicals Inc. (Bayonne, NJ), agrees that recycling could be made easier and more cost effective if there was a methodology of compatibilizing resins.

"Why is only 9% of plastics recycled from the municipal solid waste stream?" Monte asked. "Why can't Walmart reach 25% PCR content sustainability goals in blowmolded HDPE soap bottled on store shelves? Because PCR = 1+2+3+4+5+6+7 and these do not add up, as most polymers are incompatible with each other."

Monte explained that "conventional polymer compatibilization and recycled plastic centers around equipment that sorts, cleans, demagnetizes, washes, granulates, bales or melt processes recyclate. There are polymer compatibilitzers based on maleic anhydride chemistry, or bipolar thermoplastics that have affinity for two select recycled polymer streams. But currently, there's no one size fits all that will compatibilize resins," he told the audience at the Global Plastics Summit. "We may, however, have the answer."

Kenrich has developed a new titanium-mixed metal catalyst that has been shown to create in the compounding melt not alloys, but new, complex co-polymers having much higher mechanical properties, "which portends the achievement of high loadings of postconsumer recyclate in virgin polymers to meet sustainability mandates in consumer plastic packaging."

Monte said that it can be shown that 1.5% by total polymer weight of a new single-site titanium/mixed metal catalyst masterbatch in 40% active pellet (and 0.75% in 80% active powder form) produces compatible PCR plastic mixtures in the extruder melt--and acts as a compatibilizer for dissimilar polymers.

HDPE, PP and LDPE are olefins or "addition polymers," while PETE is an ester--a condensation polymer.

But, says Monte, "although PP and HDPE are both considered olefins, HDPE cannot accept more than 5% PP without creating incompatibility issues such as delamination during injection molding. The use of minor amounts of subject additives allow 50/50 blends of HDPE/PP to mold better and give stronger parts than HDPE alone."

His additives make the materials compatible.

Kenrich's chemistry appears to be gaining ground as it catches more attention. Monte claims that the company is getting "repeat orders" of significant amounts. However, he admits that for recyclers that are already invested in and set up to perform polymer sorting, his Ken-React additives are a disruptive technology.

"Recyclers are not compounders. Compounders are not recyclers and are focused on compatibilization of known streams, where I think we have more success—at least initially," commented Monte to PlasticsToday. "When Walmart and other retailers start demanding higher levels of PCR, my technology makes it possible."

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