9 Natural Fiber Welding
213
production of cotton has actually grown (but at a much slower growth rate than synthetics). Despite limitations of short staple fibers, cotton continues to be valuable
because it is generally considered to be very comfortable and does not generally pick
up bad odors, a significant customer complaint about polyester textiles.
Presently, about 59 billion pounds of cotton fiber are grown annually on 33 million
hectares of farmland [20]. For context, around 700 million hectares of grain are grown
each year globally [21]. Cotton is a relatively high-value crop, and cotton prices
are directly proportional to the length of fibers. Cotton agriculture is poised to be
substantially more valuable as nutritious edible gossypol-free cotton seed varieties
become available [22, 23]. Today, significant fractions of virgin cotton fibers are
too short to be effectively spun into yarns that are knit or woven into fabrics. These
short fibers are removed at great aggregate cost and utilized for applications, such
as rags and Q-tips. While cotton fabrics can be mechanically broken down back
into reusable fiber, both post-industrial and post-consumer recycled cotton fibers
exhibit significantly reduced length, thus greatly lowering their value and utility.
Small amounts of short mechanically recycled fibers can be blended into (re)spun
yarns, but this often requires either long staple virgin fibers and/or synthetic fiber
tows in order to make the yarns suitable (e.g., strong enough) for efficient fabric
construction. Intimately blended yarns composed of polyester mixed with cotton
fibers are particularly difficult to recycle [10].
9.2 The Gap—Lack of Sustainable + Scalable Textile
Manufacturing
It is well understood that the textile industry needs a revolution both of materials
and fabrication techniques to continue to support billions of consumers—let alone
to grow as new wealth enables larger populations to participate in the global economy. “Cradle to Cradle” and “Circular” are terms that presently receive much-needed
consideration [24–26]. Unfortunately, to date, there have been few scalable technological solutions that can meaningfully engage calls for action at global scales. It has
been suggested that biotechnology and so-called “biofabrication” techniques might
offer new circularity; however, these platforms are and will continue to be extremely
limited from the perspective of delivering relevant performance with meaningful unit
economics that can be scaled [27]. Simply put, sustainable materials manufacturing
must be scalable (e.g., unit economics that produces materials at low single-digit
dollars per pound or less) to meaningfully address global plastic pollution from the
world’s largest industries (e.g., textiles). Technologies that cannot deliver scalable
economics are simply not credible “answers” to address global sustainability issues.
Manufactured cellulose fibers are the most notable existing scalable technologies
that promote greater circularity. Both the viscose and Lyocell processes produce
regenerated cellulose fibers at cost-competitive price points and have been scaled
to around 10 billion pounds of combined annual production [28]. However, the
213
production of cotton has actually grown (but at a much slower growth rate than synthetics). Despite limitations of short staple fibers, cotton continues to be valuable
because it is generally considered to be very comfortable and does not generally pick
up bad odors, a significant customer complaint about polyester textiles.
Presently, about 59 billion pounds of cotton fiber are grown annually on 33 million
hectares of farmland [20]. For context, around 700 million hectares of grain are grown
each year globally [21]. Cotton is a relatively high-value crop, and cotton prices
are directly proportional to the length of fibers. Cotton agriculture is poised to be
substantially more valuable as nutritious edible gossypol-free cotton seed varieties
become available [22, 23]. Today, significant fractions of virgin cotton fibers are
too short to be effectively spun into yarns that are knit or woven into fabrics. These
short fibers are removed at great aggregate cost and utilized for applications, such
as rags and Q-tips. While cotton fabrics can be mechanically broken down back
into reusable fiber, both post-industrial and post-consumer recycled cotton fibers
exhibit significantly reduced length, thus greatly lowering their value and utility.
Small amounts of short mechanically recycled fibers can be blended into (re)spun
yarns, but this often requires either long staple virgin fibers and/or synthetic fiber
tows in order to make the yarns suitable (e.g., strong enough) for efficient fabric
construction. Intimately blended yarns composed of polyester mixed with cotton
fibers are particularly difficult to recycle [10].
9.2 The Gap—Lack of Sustainable + Scalable Textile
Manufacturing
It is well understood that the textile industry needs a revolution both of materials
and fabrication techniques to continue to support billions of consumers—let alone
to grow as new wealth enables larger populations to participate in the global economy. “Cradle to Cradle” and “Circular” are terms that presently receive much-needed
consideration [24–26]. Unfortunately, to date, there have been few scalable technological solutions that can meaningfully engage calls for action at global scales. It has
been suggested that biotechnology and so-called “biofabrication” techniques might
offer new circularity; however, these platforms are and will continue to be extremely
limited from the perspective of delivering relevant performance with meaningful unit
economics that can be scaled [27]. Simply put, sustainable materials manufacturing
must be scalable (e.g., unit economics that produces materials at low single-digit
dollars per pound or less) to meaningfully address global plastic pollution from the
world’s largest industries (e.g., textiles). Technologies that cannot deliver scalable
economics are simply not credible “answers” to address global sustainability issues.
Manufactured cellulose fibers are the most notable existing scalable technologies
that promote greater circularity. Both the viscose and Lyocell processes produce
regenerated cellulose fibers at cost-competitive price points and have been scaled
to around 10 billion pounds of combined annual production [28]. However, the