Green Additive Innovations Enhancing Plastics Sustainability!

TAGS:  Sustainability/Natural Solutions    

Sustainability and renewability look to be the keywords in the coming green additives marketplace. Wherever you look in the global plastics industry today, materials and additive suppliers are developing next-generation products based on renewable or recycled materials. The "green” tint is coming from following polymer additives:

• plasticizers,
• fillers,
• stabilizers,
• flame retardants,
• colorants, and
• processing aids.

For example, France’s global market leader Michelin’s involvement in the European Union (EU) funded the BlackCycle project that recovers carbon black from scrap car tires, in essence, a recycle content-based "green" additive.

To this end, Michelin acquired Lehigh Technologies, a tire granulator, and is a majority stakeholder in Scandinavian Enviro Systems, a recycled Carbon Black (rCB) producer. Michelin and Scandinavian Enviro Systems are working to overcome the major plastics application challenge where the high ash content in rCB is well above what is required to make compounds with acceptable levels of blackness.

The BlackCycle project’s goal is to develop an integrated approach to produce and use rCB and pyrolysis oil from old tires. BlackCycle is an upcycling business targeted to introduce a circular economy, whereby end-of-life tires become a source of highly technical, secondary raw materials, with no waste of resources in any part of the value chain, harnessed to specific attention to detail regarding environmental impacts. By 2030, the expectation is that one out of every two EU end-of-life tires will use this recovery process.


Michelin-sponsored, EU-funded BlackCycle Project Recovers Carbon Black From Scrap Car Tires

Moving forward, green polymer additives, like polymer additives in general, are the minor components that are formulated into a plastic resin to modify a range of its properties. The future of the green polymer additive market looks very promising with opportunities in:

• eco-friendly packaging,
• injection molding,
• automotive, and 
• biopolymer applications. 

The global green polymer additive market is currently valued at the 2.3 billion US dollar, or 5% of the total global polymer additives market, and is growing at a Compounded Annual Growth Rate (CAGR) of 12% to 7.1 billion US dollar by 2032. The major drivers for this market are the increasing inclination for green plastics in packaging and other plastic applications, stringency in government and environmental regulation to use ecofriendly chemical products, and the growing demand for long-term low-cost fully green polymers.

Identify cutting-edge advances in green additives to focus your R&D on right projects»»


Let’s now turn our attention to reviewing six green additive innovations.

BASF’s BMB Plasticizers Saving Fossil Fuel Resources

To start with, BASF has recently developed, and commercialized new plasticizers based on alternative raw materials referred to as circular feedstocks. In this approach, both renewable and chemically recycled feedstocks are the starting point materials in place of fossil fuel resources.

Plasticizers are built using the BioMass Balance (BMB) approach allowing these alternative feedstocks to be processed with traditional fossil fuel base materials in existing BASF manufacturing lines, apportioning these biomass equivalents to specific products as chemically designed. Stated simply, the core mass balance approach provides a set of rules for how to allocate the renewable/recycled content to different products to be able to claim and market the content as "recycled."

BASF developed BMB plasticizers include following products:

• Hexamoll® DINCH
• Palatinol® N
• Palatinol® 10-P
• Plastomoll® DOA

BASF’s Biomass Balanced Plasticizers Saving Fossil Resources and Reducing CO₂ Footprint

Bio-naphtha, commonly called biogas, derived from organic waste or vegetable oils is the alternative feedstock, as certified by REDcert2. REDcert2 is an efficient certification solution for the use of sustainable biomass as a material in the chemical industry. BASF has recently offered Hexamoll® DINCH - Ccycled™, a chemically recycled feedstock-based, non-phthalate plasticizer. Here, pyrolysis oil from BASF’s ChemCycling project supplies the alternative feedstock.

Omyas’s Cost-effective Calcium Carbonate Filler for PET Bottles

Next, Omya has commercialized the OmyaPET® calcium carbonate (CaCO₃) filler for opacifier use as an extender for Titanium Dioxide (TiO₂) white opaque coloring of Polyethylene Terephthalate (PET) ultra-high temperature (UHT) milk bottles and biaxially oriented film. As a TiO₂ extender, OmyaPET® provides a low environmental footprint and lowers manufacturing costs, without sacrificing optical and mechanical properties.

The OmyaPET® filler is produced from a 100% recycled CaCO₃ feedstock that otherwise would have been landfilled. It is very acceptable for food contact applications primarily due to the fact that it is not considered to be a post-consumer recycled additive. It only requires standard surface functionality modification to be qualified for PET use.

Omya’s OmyaPET® calcium carbonate (CaCO₃) filler additive assists in two critical ways:

1. When standard calcium carbonate is used in PET extrusion applications like milk bottles or film, excessive degradation results in frequent product discoloration and property deterioration. The OmyaPET® filler is very stable to the point that in plastic manufacturing processes like bioriented PET film and stretch blow molding where the compounded PET material is stretched, a very laminar structure is formed with a desirable high opacity whitening effect. Furthermore, in PET UHT milk bottles, up to 70% of standard TiO₂ is replaceable by OmyaPET®, resulting in major and sustainable cost savings.


2. One further OmyaPET® filler advantage is that in the reheat blow molded preform step before finished PET bottle blowing energy used in manufacturing is reduced because with less TiO₂ Infra-Red (IR) heaters radiation will reflect a lot less, for a measurable cost saving.
   
   
   Various Omya’s OmyaPET® CaCO₃ Filler Levels Light Transmission Rates for 1-liter UHT Milk Bottle

Sumitomo’s Sustainable Plastic Stabilizer for Food Packaging

Continuing, Sumitomo Chemical’s Sumilizer® GP stabilizer has opened up a new sustainability focus in which it qualifies as not being a Non-Intentionally Added Substance (NAIS), which is of increasing importance in food packaging. In Sumitomo’s case, it refers to their Sumilizer® GP plastic stabilizer additive as an acceptable, sustainable ingredient in Polyethylene (PE), Polypropylenes (PP), or Polystyrene (PS) film wraps and molded or thermoformed parts in food protective applications.

The key aspect of the Sumilizer® GP antioxidant-type stabilizer is that it has:

• a hybrid type
• single molecule
• combined phenolic and phosphite chemistry.

This chemistry gives the Sumilizer® GP stabilizer its excellent processing stability and color consistency at a lower by-weight loading level compared to standard stabilizers available on the market. More importantly, competitively it is entirely free of nonylphenol, a substance of very high concern currently to regulatory bodies.


Sumitomo’s Sumilizer® GP (Blue) Stabilizer Performance Versus Standard Systems (Red, Green)

Of equal importance is Sumitomo Chemical’s Sumilizer® GP stabilizer which has been fully approved by EFSA, the European Food Safety Authority based on meeting specific migration limits. It exhibits high resistance to nitric oxide gas in polyolefin food packaging which can lead to product discoloration. Its capability to be used at low dosage rates in finished compounds makes it ideal for recycling purposes.

Momentive’s Silicone Flame Retardant in Clear Plastic Films

Of ongoing interest, Momentive has commercialized SFR320, a silicone flame retardant (FR) additive. It is targeted for use in clear plastic resins like Polycarbonates (PC), retains high optical transparency in the base polymer, and is effective at low dosage rates. Directives in both Europe and the United States are driving electrical and electronic applications across virtually all industrial plastics end-use markets towards nonhalogen systems that are also more easily recyclable. Very low toxicity and excellent mechanical property retention are hallmarks of silicone-based chemistries.

No.	Composition [%]			FR Testing (1.6 mm)	Transparency (1 mm)	Izod Impact Notched (-30°C)
	PC*	Anti-dip**	SFR 320	UL 94***	[%]	[KJ/m2]
1.	100	0	0	V2	89	12
2.	99.85	0.15	0	V2	88	17
3.	98.85	0.15	1	V0	88	14
*General purpose medium viscosity non-FR Polycarbonate. **Sulfonate salt. *** Test results are composition, molding, & operator dependent.

Momentive’s SFR320 Flame Retardant (3rd Bottom Line) in Polycarbonate (PC) at 1% Loading
In the preceding table, Momentive’s specialty additive at a 1% loading will give PC an Underwriters Lab (UL) V-0 rating and exhibits very good miscible compatibility across many transparent resin systems. Momentive is also targeting Electric Vehicle (EV) use for its SFR320 FR additive in transparent front and rear headlight covers. Silicone-based FR systems are less corrosive in nature than traditional halogen-free flame retardants, which in turn increases EV fire safety.

Avient’s ColorMatrix™ Colorants Reduce Discoloration in Recycle PET Bottles

Delving further, evolving Avient’s ColorMatrix™ Optica-type color additives will minimize Polyethylene Terephthalate (PET) recycle discoloration. Repeated PET bottle recycling degrades properties and brings on discoloration. Currently, 30% recycled Polyethylene Terephthalate or rPET is used in many bottle types. For example, 9% of rPET will go through two or more recycle loops. With 50% rPET in a bottle, 25% of the given material undergoes two or more recycle loops.

At this point, bottle quality is subjected to increasing color variation, and affected by:

• increased yellowing, as measured by the b* factor
• and discoloring, as quantified by the L* factor.

Avient has initiated the development of new liquid colorant additives. These additives will be applied to Post Consumer Recycle (PCR) flake prior to extrusion into rPET pellets.

Various colorant chemistries are being evaluated. Tests have shown that flake coloring treatments can have a significant impact on PET color levels. A huge effect occurs in stabilizing color formation. Preliminary rPET compound treatments can decrease b* yellowing values by 15 units (10 versus 25) Similarly, the L* factor estimates darkness, scale quantified from 0 (black) to 100 (white), where rPET usually rises from 70 to 80.


Avient’s ColorMatrix™ Colorants Cuts rPET Flake Yellowing (b* Chart-Yellow) and Discoloring (L*-- Green)

Emery’s Castor-based Processing Aid for PVC Applications

Let’s conclude with Emery Oleochemicals’ Green Polymer Additives business unit which has commercialized a bio-based combination processing aid for rigid PVC applications, which is being used at the industrial scale. Emery’s Loxiol® G 19 is a drop-in, functional alternative to castor-based PVC processing aids, or 12 hydroxy stearic acid (12-HSA), which is also bio-based, but which is subject to continual supply chain disruptions, limiting it in high volume processing aid use. Importantly, PVC formulations typically contain a complex blend of stabilizers, processing aids, and other additives that are designed to work together in careful balance.

Loxiol® G 19 exhibits good formulation compatibility, demonstrates reduced stickiness in use, and has good anti-plate-out characteristics. It is qualified for indirect food contact applications. Substances that might come in contact with food, such as on the outside of a food bag or carton, are defined as indirect contact. Furthermore, Loxiol® G 19 does not affect the vicat softening point, mechanical properties, or the color of the plastic end product.


Emery’s Loxiol® G 19 Processing Aid (Green Bar) Versus Castor Oil-Based 12-HAS (Blue Bar)

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