FEEDSTOCK TO FASHION

PHOTO: DuPont™ Sorona®

Feedstock to Fashion 2018-01-12T06:03:36+00:00

THREE KEY STAGES

The overall sustainability of biosynthetic textiles depends upon the choice of feedstock, the manner in which they are processed, and their end-of-life options.

Transparency through manufacturing will ensure customers can align their use of biosynthetics with their company strategies and priorities. Questions should be asked throughout the supply chain to ensure understanding at each level.

Stage 1: Feedstock

The choice of biobased feedstock typically has the most impact on the sustainability attributes of a biobased material.

The type of biobased feedstock, how it is grown and produced, the technology used to covert the biobased feedstocks to chemicals and polymers, and the effects production of biobased feedstock has on land use are all important in evaluating sustainability impacts of bio-based materials.

Stage 2: Processing

Biosynthetics can be either a drop-in material (that can be used in existing equipment, manufacturing and recycling processes), or new materials (that have different properties that could require different processing and/or recycling infrastructure).

The type of material and process method used will have an effect on sustainability impacts, scaling- up potential and cost.

Stage 3: End-of-life

End-of-life options are determined by the type of biosynthetic material (whether it is a ‘drop-in’ or a new material), the percentage of bio content, and the processing method.

Current end-of-life options (from least to most desired) include: landfill, incineration, composting, and recycling (which holds the greatest positive result when recycled within the same polymer family).

FEEDSTOCK

Feedstocks are the raw material building blocks that are used to produce the chemicals required in polymer production. The choice of feedstock determines the quality, cost and final sustainability and performance attributes of the polymer.

Polyester based polymers: Predominantly use starch/sugar based feedstocks
Polyamide based polymers: Predominantly use lipid/oil based feedstocks

FIRST, SECOND & THIRD GENERATION

The resources used for biopolymers are ever evolving to both improve performance and reduce impact. The industry is ultimately working towards lessening the impact of biopolymers on land use and food commodities. This has resulted in a distinction between 1st, 2nd and 3rd generation bio feedstocks, based on the development stage and the bio resource that they were derived from.

Crops
(1st generation)

Commercially available at scale.

Bio feedstocks currently used for production of biobased fuels and chemicals include:

Corn, sugar cane, sugar beet, wheat and sorghum.

Waste
(2nd generation)

Pilot and demonstration stage (not commercially available at scale).

Bio feedstocks requiring further technical development and include:

Biomass resources from agriculture and forestry.

Non-Food Resources
(3rd generation)

Concept and pilot stage (not commercially available at scale).

Feedstock is from algae, bacteria, etc. grown specifically as a bio resource.

Algae is grown with water, CO2 and sunlight and does not require any food source.

TYPES OF FEEDSTOCK

STARCH/SUGAR

Starch and sugar are the most widely used feedstocks for biosynthetic polymers, with starch used for 80% of bioplastics today.

Glucose and sugars are taken directly from sugar-based crops. In the case of starch-based crops, glucose and sugars are broken down from the plants.  Fermented sugars can be processed further into Ethanol, Butanol, Succinic Acid, and other chemical building blocks for biopolymers.

Advantages of this type of feedstock include: Established supply chains, flexibility of growing regions, and ease of processing.

Renewable:
  • Yes
 Ease of process:
  • Established supply chains
  • Easily converted into sugars
  • Cleaner feedstocks reduce costs for conversion to polymer
 Regions harvested:
  • Corn: US, China, Brazil
  • Cane: Brazil, India, China, Thailand
  • Beet: Russia, France, US, Germany
Sustainability:
  • Land use – TBC
  • GMO – Mixed
 Cost:
  • Cost varies depending on type of starch/sugar used, region of harvest and ease of extraction
  Feedstock source:
  • Sweet sorghum
  • Sugar beet
  • Sugar cane
  • Other starches
  • Cassava
  • Corn/maize

LIPIDS/OIL

These feedstocks are used specifically in textiles within the polyamide area, with a smaller usage than starch and sugar-based feedstocks.

Despite the regional or seasonal variation, the castor oil crop is harvested with relative uniformity of chemical characteristics, making it an attractive feedstock choice.

Renewable:
  • Yes
 Ease of process:
  • Most easily refined
  • Castor oil is grown with relative uniformity
 Regions harvested:
  • India, China, Brazil
Sustainability:
  • Grown on land not suitable for food crops
  • GMO – Mixed
 Cost:
  • Typically more expensive
  Feedstock source:
  • Castor oil
  • Soybean oil
  • Palm oil
  • Waste food/cooking oil

BIOMASS

Biomass feedstocks are derived from cellulosic-based plants. They are either grown specifically for use as biomass raw materials or are secondary to a subsequent crop process in which their byproducts, or waste, are used as biomass.

Biomass crops are not considered competition to food crops. They utilize a greater amount of the plant therefore providing higher yields.

As biomass feedstocks are more fibrous than other feedstocks, they require digestion or deconstruction prior to conversion into chemicals.

Renewable:
  • Yes
Source:
  • Cellulosic plant
 Ease of process:
  • Technology for biomass processing at large scale (feedstock to chemicals) is currently in development and not yet commercially available.
 Regions harvested:
  • TBC
Sustainability:
  • Land use – TBC
  • GMO – Mixed
 Cost:
  • Cost varies depending on cost of biomass, scale, labor, machinery and access.
  Feedstock source:
  • Agricultural waste
  • Trees
  • Grasses (Sorghum)

PETROLEUM (FOR PARTIALLY BIO)

Petroleum is the traditional feedstock for synthetics. It is a finite resource that increases CO2 emissions and is a liability in terms of its long-term price and supply instability. Renewables, such as biosynthetics, offer an attractive alternative.

Biobased feedstocks are used together with petroleum-based chemistry in partially biobased solutions today, however, the industry is working towards creating 100% biobased solutions that will reduce the need to rely on petroleum in the future.

Renewable:
  • No
 Ease of process:
  • Established
 Regions harvested:
  • Not applicable
Sustainability:
  • Non-renewable resource
 Cost:
  • Market price per barrel
  • Economies of scale through large-scale production drive competitive cost

MARKET FOCUS

Polyester accounts for 64% of global fiber consumption annually. Due to this market size, it is understandable that biobased alternatives to virgin polyester offers the greatest opportunities for the sector, and is driving innovation as the largest growth area for biopolymers.

CHEMISTRY

Biobased polymers have been developed to offer a lower carbon footprint and more sustainable alternatives to conventional fossil fuel based synthetics, including:

PLA (Polylactic Acid)

 The PLA polymerization process is two-part, converting starch to lactic acid and lactic acid through polymerization to the PLA polymer. For example, NatureWorks’ Ingeo.

Example of Biobased PLA feedstock and production process:

 Biobased PTT (Polytrimethylene Terephthalate)

PTT is made up of two monomer units, 1,3-propanediol and purified terephthalic acid (PTA). A partially bio based polymer is possible where the 1,3-propanediol is derived from annually renewable plant based resources. For example, DuPont™ is a main supplier for bio-based PTT, Sorona®. Commercialization of bio-based PTA would enable fully bio-based PTT.

Example of Biobased PTT feedstock and production process:

 Biobased PET (Polyethylene Terephthalate)

Ethylene glycol and terephthalic acid are monomers used in the synthesis of PET. Today partly biobased PET is produced commercially by using biobased mono ethylene glycol (MEG). Far Eastern New Century (FENC) worked with Virent to convert the BioFormPX® paraxylene to bio polyester, and to produce the first 100% bio polyester fabric and shirt.

Example of Biobased PET feedstock and production process:

Biobased PA (Polyamide/Nylon)

The use of DA10 and DC10 monomers from sebacic acid (which comes from castor oil) is being used in production of PA6,10, PA10,10 and PA10,12, as well as Arkema’s PA11 – Rilsan – made from 100% biobased 11-aminoundecanoic (A11) acid monomer (also sourced from castor oil).

Example of Biobased PA 10,10 feedstock and production process:

YARN & FABRIC MAKING

Molten polymer is extruded through spinnerets to form continuous filament strands, which can either be kept as filament, or cut into shorter staple lengths and spun into yarn.

As with other fabrics, a pre-production assessment should be carried out to ensure full suitability of the fabric for intended use.

END-OF-LIFE

Higher value can be gained from biosynthetic textiles when engineered for recycling within existing recycling infrastructure.

END-OF-LIFE OPTIONS FOR BIOSYNTHETICS

There is currently a range of end-of-life options for biosynthetics. Each raw material, together with its processing methodology, will have a specific preferred end-of-life route.

Landfill

Raw material type, plus the processing method used, determines the suitability of landfill disposal. The aim is to keep biosynthetics out of landfill.

Incineration

Product is incinerated, creating energy. Energy recovery from waste is often called waste-to-energy but it is a less desirable option since it does not eliminate waste.

Compost

Just because a textile product is biobased does not necessarily mean the product is biodegradable or compostable. Marketing biodegradation via composting routes requires full certification.

Recycle

Each raw material used, together with its processing method, determines the ability for biosynthetics to be recycled. Note: each biosynthetic needs to be recycled within its specific recycling channel (i.e. PLA within a PLA specific recycling stream).

Reuse

A products “first life” is extended by building in durability in product design, and facilitating reuse and repair options.

As a core principle of sustainability, it is important to maintain the 4Rs of Reduce, Reuse, Recycle, and Recover.  Many biobased products can be recovered in their lifecycle via composting or recycling, although adequate composting and recycling infrastructure is still needed. Supply chain partners can advise on a case-by-case basis which of the five scenarios above are most appropriate.

Biodegradability is often misconstrued as a benefit of biosynthetics. In specific conditions, biosynthetics can biodegrade through composting processes, however, some petro-based synthetics can do the same.

It is a misconception that all biosynthetics are compostable, or that compost is a preferred option for end-of-life. The preferred end-of-life option for biosynthetics is upcycling or recycling.