Making a Play With PHA

The drive toward sustainability is requiring North American processors — especially those serving the disposable packaging markets — to give more consideration to their material choices. Whether driven by their brand owner customers or internal demands or goals, molders and extrusion processors slowly are investigating and even in some cases deploying new materials and structures aimed at making their products greener.

Of course, sustainability has many definitions and takes on many shapes and forms. Where material choices are concerned, it could mean moving toward single-resin structures that are more readily recyclable. This is an emerging trend in flexible packaging, where all-PE multilayer structures are replacing multipolymer systems of those that combine plastics and other materials. There is also a growing push in packaging and beyond, or products made with a healthy dose of postconsumer reclaim. And biopolymers are also gaining a toehold in the green movement.

There are a lot of studies out there projecting the future of the biopolymers market, and all are projecting robust growth. One, from BCC Publishing, forecasts the global market for the materials to increase from $4.8 billion in 2022 to $14.4 billion by 2027, at a compound annual growth rate (CAGR) of 24.8% from 2022 through 2027.

One of the leading biopolymer choices is polyhydroxyalkanoates (PHA). In Woburn, Massachusetts, CJ Biopolymers has an application development and technical support team aimed at helping processors transition from conventional polymers to PHA or PHA-based products for applications that include blown and cast films. molded cutlery to extruded straws and thermoformed food service bowls.

PHAs are naturally derived — sugars sourced from plants such as sugar cane, tapioca, corn and cellulosic biomass — and produced sustainably. They can be used as building blocks replacing and improving the functional characteristics of a broad range of polymers in the production of finished goods or as starting points for sustainable chemistry. PHAs work well as modifiers to other polymers or biopolymers and can be used to increase biobased content, accelerate biodegradation and improve the functional properties of resins and finished products.

CJ develops custom blends using amorphous PHA polymers with other polymers, notably other bioresins such as polylactic acid (PLA). These PHA-based products can be compounded and processed using conventional plastics processing equipment. CJ can increase PHA content in microorganisms from about 5% accumulation in the wild to up to 85% through fermentation via engineered microbial strains.

CJ is one of the largest industrial fermentation companies in the world. It extended its technology platform downstream to polymers in 2016 with the purchase of Metabolix. In 2021, it brought on Max Senechal as its chief commercial officer. It was a return of sorts for Senechal, who had been with Metabolix under its prior regime.

“I often catch myself saying I rejoined CJ, but I have actually rejoined the company that CJ acquired,” Senechal says. The purchase of Metabolix by CJ represented a relaunching and “turbocharging” of the product line, he notes. Senechal elaborates, “We have learned quite a bit, and CJ has been able to improve the technology significantly from a fundamental microbial perspective and from a fermentation scale-up perspective. That has had an impact on both the technical and economic performances.”

One of the biggest differences made by CJ can be seen by visitors to its North American headquarters in Woburn, Massachusetts. “Now it’s a polymer science lab, which we call our Center of Excellence,” Senechal says, “and that is a significant transition for us. If you came here two years ago, you would have seen fermenters, etc. But once we relaunched the technology, we needed to connect the technology to the polymer world. We were no longer talking in terms of strains — we were talking about polymer science and connecting these two worlds was a challenge for the industry.”

“CJ has been able to improve the technology significantly from a fundamental microbial perspective and from a fermentation scale-up perspective. That has had an impact on the economic performance.”

The facility is equipped with lab-scale compounding equipment and blown film lines, small-tonnage injection presses and an additive manufacturing machine. “We can test and develop tailored formulations, do testing on the performance and the properties of the technology. We also invite customers here to work with them and talk to them about how to use it on their machines with our resins,” Senechal adds.

CJ does not produce commercial quantity resins in North America, large-scale takes place at an existing CJ Biomaterials site in Indonesia. From Woburn, it can provide its customers with small quantities to conduct trials. Senechal elaborates, “A customer might come to us and say, ‘I want to try it on my production lines. Can I get a couple of hundred pounds? And the answer is yes.”

When necessary, it will utilize the services of its toll compounding partners for larger runs. Or, in the case of a processor that does its own compounding or has a network of compounding partners, it will provide just the formulation. Neat resin is furnished from a plant in Indonesia, which has 10,000 tons of pelletizing capacity on two lines, one devoted to its amorphous grade the other to its more recently launched semicrystalline line.

Explains Senechal, “We are first and foremost a PHA resin manufacturer and supplier. We don’t own compounding capabilities in the U.S. We have strong relationships with a few compounders, and if we need to provide compounds, we will work with these tollers to prepare a compound needed by the customer. Of course, it is easier for us to sell the neat resin. But we understand that, depending on the application, customers need some tweaking in the formulation. There is no silver bullet. There’s no one polymer that does everything, so therefore the compounding becomes necessary. We will work with people to help develop that compound. Sometimes we’ll just provide the formulation.”

Wide Range of Applications

Today, CJ Biomaterials offers two basic PHA resin grades — an amorphous (aPHA) product (trade name A1000P) which is primarily marketed as a modifier for other biopolymers, mainly PLA; and a semicrystalline (scPHA) grade (trade name S1000P) positioned as a primary biopolymer for a variety of applications, including injection molding, extrusion, coatings and films. It sells these two grades in neat form or, depending on the circumstances, CJ Biomaterials develops and offers a few compounds based on its PHAs that are adapted for the specific requirements of various applications.

For film extrusion, CJ Biomaterial offers compounded resins based on PLA and amorphous PHA. These compounds are said to improve functional performance and enable faster composting relative to PLA. The films made of PHACT compounds also are said to have superior sealability, flexibility and less noise compared to PLA-only films. Final products made of PHACT compounds are said to have faster rates of biodegradability than PLA-only films.

For tube extrusion, CJ Biomaterials’ S1000P resins are well suited to straws. This is an environmentally friendly semicrystalline biopolymer with excellent functional performance and certified for marine, soil and compostable.  For some applications, the addition of aPHA increases flexibility and impact strength, and is well suited for demanding straw applications.

For sheet extrusion/thermoforming, the product line consists of blends of aPHA and PLA that are said to improve functional performance and enable faster composting relative to PLA. The addition of aPHA to PLA increases flexibility and impact strength, limiting breakage during production and distribution, CJ says. These blends can also improve productivity during the thermoforming process. These compounds are said to reduce the thickness of final products by 12-15% compared to PLA, resulting in cost savings.

For injection molding, semicrystalline biopolymer compounds are available that reportedly improve functional performance and enable faster composting relative to PLA. The addition of aPHA to PLA increases flexibility and impact strength, and enhances water/oil resistance. Aimed at cutlery, containers and other products, these compounds are also said to improve processability during molding, enabling greater design flexibility. CJ says the mold shrinkage of these grades is like that of ABS, meaning existing molds for ABS can be used.

CJ also offers a masterbatch form of aPHA/PLA for converters who wish to dial in the addition of aPHA at their machine for these processes where the objective is to modify PLA.

States Senechal, “We’re seeing a lot of traction right now in food service, meaning disposable cutlery, straws, plates and such. There is a lot of momentum in this space because there is a strong push for compostable solutions. A lot of the venues, for example, today are looking for all-compostable solutions. They’ll draw a perimeter around the venue so that everything that comes in can be composted. Biopolymers are particularly well-suited in this case of applications.”