What is Hemp?
Hemp is a variety of the plant cannabis sativa. Unlike its cousin, marijuana, industrial hemp contains virtually none of the chemical tetrahydrocannabinol (THC) which produces psychoactive reactions when smoked or ingested. Hemp is a commercial crop grown for its seeds and fibers.
The production of industrial hemp was banned in the U.S. following passage of the Marihuana Tax Act of 1937. However, the Agricultural Act of 2014 opened the door for states to establish their own research and production programs. Currently 28 states have begun the process but only a limited number of pilot programs have been conducted. There is still essentially no local supply of industrial hemp for clothing and the vast majority of hemp clothing manufactured in the U.S. uses textiles imported from China.
The Benefits of Hemp
Hemp is much better for the environment than cotton. Not only do hemp plants use half the amount of water as cotton and none of the pesticides, they produce twice as much fiber per unit of land. The parts of the plant not used for clothing have other applications, making it more versatile as an industrial crop. Hemp fibers woven into textiles last longer than cotton, resulting in a higher quality product at a better value. It’s easier to dye hemp and it’s less prone to fading and stretching. Hemp clothing has other properties that make it more comfortable to wear than cotton. It’s cooler in the summer, warmer in the winter and has moisture-wicking and anti-microbial properties.
There are two methods for processing hemp with two resulting hemp fabrics: mechanical hemp and viscose hemp.
Mechanical hemp is the result of the traditional method of processing a hemp plant for its fibers. The fibers are mechanically pulled apart and then spun into thread and woven into fabric. This is the most sustainable approach, but the downside is that only about 50% of the plant is used and the resulting textile is notoriously rough.
Viscose hemp is a soft rayon fabric made from hemp. While this method uses the entire hemp plant, it involves chemical and energy inputs which make it a less environmentally-friendly procedure than the mechanical process. This is a semi-synthetic fabric because, unlike purely synthetic fibers which are made from oil, the raw materials are organic. Viscose fabrics can be made from many plants, including trees, bamboo, soy and sugar cane. Due to the radical transformation of the source material, the Federal Trade Commission has ruled that products made from viscose bamboo cannot be labeled as ‘bamboo’. As such, I have to question whether viscose hemp actually retains any of the beneficial properties of hemp that make it a desirable material for clothing.
There are a few American clothing companies producing hemp shirts:
- Dash Hemp’s shirts are 55% hemp and 45% organic cotton. Made in the USA of imported hemp.
- Jungmaven‘s shirts are generally 55% hemp and 45% organic cotton but they also offer 30/70 blends, 60% viscose hemp and 40% organic cotton blends as well as 100% hemp shirts. Made in the USA of imported hemp.
- Recreator does not use viscose hemp. While they previously sold a 100% hemp shirt called the Hundo, their regular lineup of shirts consists of 30% hemp and 70% organic cotton. Made in the USA of imported hemp.
- Superego‘s shirts are all 60% viscose hemp and 40% organic cotton. Made in Bangladesh.
Spinning a Solution
I guess my biggest question is what approach to take? Is it possible to use 100% mechanical hemp fabric and produce clothing that is as comfortable as traditional cotton or poly-blends? Where does viscose hemp rank in terms of environmental impact versus cotton? What about first processing hemp mechanically and using the remainder of the plant to create viscose hemp, then blending the two together to make 100% hemp fabrics? Would, say, an 80% mechanical / 20% viscose blend, be appropriate for denim, a 60/40 blend for pique knit polos, or a 30/70 blend for a jersey knit T-shirt?
T-shirts are generally made with a jersey knit fabric.
Polo shirts are generally made with a pique knit fabric.
The quality of a T-shirt is generally assessed by its weight, hand (=softness) and durability, all of which are determined by the construction of the fabric used.
The fabric weight is measured in ounces per square yard in the U.S. and grams per square meter in most of the rest of the world. Lighter shirts are in the 3–5 oz range, regular shirts around 5.5 oz, and heavyweight tees climbing to 6 oz or higher.
Traditional cotton fabrics come in three levels of quality: open-end yarn, ring-spun cotton and ring-spun combed cotton. Ring-spun cotton produces a smoother and longer yarn than open-end because it goes through a spinning process that straightens and softens each fiber. Combing that ring-spun yarn remove impurities and makes for an even softer feel. The term singles refers to the gauge, or thickness of the yarn, with a higher number indicating a softer feel: 20 singles is fairly standard while 30 singles is more luxuriant.
Further research is required to determine how these standards apply to 100% hemp fabrics or hemp/cotton blends.
https://en.wikipedia.org/wiki/Hemp • https://en.wikipedia.org/wiki/Legal_history_of_cannabis_in_the_United_States • https://en.wikipedia.org/wiki/Agricultural_Act_of_2014 • http://www.ncsl.org/research/agriculture-and-rural-development/state-industrial-hemp-statutes.aspx • http://www.votehemp.com/us-state-industrial-hemp-legislation.html • http://www.hemp.com/2011/04/wear-your-hemp-proudly/ • https://en.wikipedia.org/wiki/Rayon • https://en.wikipedia.org/wiki/Viscose • https://www.spectratees.com/what-is-ring-spun-cotton-the-difference-between-30-singles-20-singles/