Fibers are currently used in a multitude of industries. And fibers made from hemp have the potential to be integrated into numerous, diverse enterprises. As companies move away from petrochemicals and fiberglass, hemp is poised to supplant synthetics as a renewable and sustainable solution to environmental concerns.
The modern use of fibers is vast and includes industries such as electronics, telecommunications, textiles, aerospace, defense, construction, automotive, and sporting goods. The added benefit of eco-friendly natural fibers make them a growing commodity. Whether it's due to new ecological construction concepts, regulations, certifications, health issues, or the environmental impact of product manufacturing, use, and disposal – industries are increasingly relying on environmentally friendly filling and insulating materials made of pulp or fibers.
While natural fiber products are conquering more and more industrial and consumer fields, it's not just for environmental reasons. In the food and beverage industry, natural fibers can replace plastic wrapping, increasing food safety with improved properties for food preservation. The automotive industry has started using plant fibers for manufacturing lightweight car bodies. And the construction industry is always looking for ways to improve efficacy. The performance of natural insulating materials is equivalent to that of many mineral and synthetics. But natural insulating materials are less risky for the installer. Furthermore natural fibers are usually harmless and easier to handle for disposal.
Industries which utilize fibers all have their unique set of requirements. These specifications are numerous and can include length, thickness, strength, absorbency, bonding, weight, color, stretch, conductivity, heat capacity, risk to health, and biodegradability.
“Industries which utilize fibers all have their unique set of requirements”
In its raw form hemp bast fibers exist bound together in the bark of the hemp stalk. The first step to make them available is to separate the bark fibers from the hurd in a process known as decortication. But this process needs to be specific to the market for the fibers.
Bast fibers destined for textiles requires the hemp to be grown for fiber and harvested prior to flowering to keep lignin levels low. The bast fibers need to be at least 36” long and clean of any hurd. This is similar to flax fibers used to make linen. They should not be bent or tangled, and aligned in the same direction. This requires a specific method of decortication to achieve these qualities. These bast fibers do not need to be combed or separated from one another at this stage since that process will be done at the textile factory.
Hemp fibers obtained from a grain crop require a different type of decortication since they will be shorter, drier, and have higher levels of lignin. Different methods of decortication are going to result in a different qualities of fiber. They may be shorter, less uniform in length, tangled, and have bits of hurd attached. Marketing these fibers will require further refinement and selection to increase their range of uses.
Both hemp grown for fiber or grain contain bast fibers which are held together by lignin. They frequently need to be separated from one another by either physically combing them or chemically removing the lignin in a process known as degumming. Both processes can thin the fibers as well as shortening their length. Once the fibers are separated from one another, they may be further sorted based upon length and thickness. Other machinery exists to reduce the fibers even further in a process known as reduction. Every application for fibers is unique and require its own set of parameters.
Hemp core fibers do not undergo the process of combing and degumming, but they still need to be standardized in length and thickness to be useful in specific applications. Hammer mills and screens are used to achieve this uniformity.
Not only do fibers need to be a certain length or thickness, they frequently need to be uniform. The average difference in length and/or thickness between the fibers is referred to as standard deviation. Some applications can accept a greater tolerance of variation than others depending on their use.
Cleanliness is also an issue. Fibers need to be free of small particles or contamination. Applications such as pulp for paper and composites may require a purity of greater than 99.9%. Other products do not require such a degree of cleanliness.
Color may also play a factor in the hemp fiber. The natural color of hemp can vary from yellowish white to green to brown to dark gray. The color depends upon the strain of hemp grown, the length of the grow, the method of harvesting and retting, as well as the processing technique. To get a consistent color, fibers may need to be bleached or dyed.
“The successful entrepreneur will need to consider all these parameters and understand the needs of their target customers”
How does all this information relate to the hemp industry as a whole? The successful entrepreneur will need to consider all these parameters and understand the needs of their target customers. Once the hemp fiber is harvested, processing facilities will be required to modify their fibers to fit their client’s expectations. Having the ability to adjust the fibers for length, width, and color opens the door to multiple industries and clientele. Uniformity of of the fibers are part of the quality control. The companies who can master the manipulation of hemp fibers and provide consistent quality will expand their markets and be the the most successful.
Hemp can compliment cotton, but will not supplant it as a textile fiber
It has been suggested hemp could supersede cotton in many aspects of the apparel industry. While hemp has some environmental advantages over cotton, its specific characteristics and behaviors as a cloth prevents it from completely replacing cotton fabrics.
Hemp’s environmental benefits over cotton are well known. Hemp can produce more fiber per acre than cotton while requiring 20% less water. Hemp can be grown without pesticides or herbicides, while conventional cotton requires both insecticides and herbicides to cultivate.
However hemp requires more processing to get the fibers to a form where they can be spun successfully into yarn. Cotton fibers exist individually in a cotton boil. Each fiber is separate from one another and are more uniform in length and width compared with hemp. This makes it easier to spin cotton into yarn. Hemp bast fibers exist as a group in the bark. They are attached to one another, bonded by lignin. Hemp fibers need to be separated from one another either by physically combing them or chemically removing the lignin in a process known as degumming.
Approximately 80% of hemp bast fibers are long, running the entire length of the stalks. These are referred to as line fiber. Shorter hemp fibers are referred to as tow. Degumming the hemp fibers separate them from each other, creating a mix of both long and short fibers. The long and short fibers are divided from one another by combing. The long fibers of 4” - 6” are spun into yarn using flax spinning machines. These yarns are used for 100% hemp fabrics which are similar to linen. The shorter fibers of 1 1/8” to 2” long are blended with cotton and spun using cotton spinning machines to produce hemp/cotton blended yarns.
“Cottonizing hemp does not mean turning hemp into a cotton like fiber. It refers to shortening all the long hemp fibers to the same length as cotton”
Is it possible to convert hemp fibers into cotton fibers through a process known as cottonization? No. Cottonizing hemp does not mean turning hemp into a cotton like fiber. It refers to shortening all the long hemp fibers to the same length as cotton, allowing them to be spun into yarns with cotton spinning machinery. It is better to make 100% hemp fabrics from the long fibers and blend the naturally occurring shorter fibers with cotton. If the fibers are all shortened and made into a 100% hemp fabric, the resulting material has a lower strength and quality compared to long fiber hemp.
Both hemp and cotton have unique properties which make them better suited for different uses. Hemp is a stronger fiber requiring a greater amount of force to break. When a stronger and more durable fabric is required, hemp is the better choice. Hemp has a lower percent elongation compared to cotton. This mean when the fiber is pulled to its breaking point, hemp will not stretch before it breaks. This makes hemp the better choice for upholstery where the fabric needs to remain taut over the lifetime of furniture.
Hemp is a hollow fiber rendering it more water absorbent than cotton. Hemp fabrics will hold dye better than cotton and are less likely to fade. The porous nature of the fibers contribute to better air circulation, resulting greater breathability. The flow of air helps prevent the growth of anaerobic bacteria, preventing the odor of sweat. In cold weather the porous nature traps warm air, insulating the body.
Cotton does have some advantages over hemp. Cotton fibers are stretchy and tend to cling to one another. This makes it easier to spin them into yarns and create naturally stretchy knit fabrics like jersey and fleece. Cotton fibers are thinner and more uniform in size, allowing them to be spun into finer yarns. These yarns produce thinner, softer, and more tightly woven fabrics. This provides a greater variety of textiles to be made from cotton. Cotton fabrics shrink when washed and expand with use, providing snug fitting clothing like jeans. Clothing made of cotton will wrinkle less than hemp.
When hemp and cotton are blended together, both their properties are incorporated into the fabrics. These two fibers compliment one another rather than compete. These textiles are stronger, more absorbent than cotton fabrics, yet softer and less prone to wrinkling than hemp alone. By blending cotton with hemp and incorporating both their attributes we can reduce our reliance on petroleum based synthetic fibers.
Hemp as a Replacement for Flax
Increasing both supply and demand are necessary for the hemp fiber market to grow and develop. Supply and demand are not exclusive, but rather affect one another. The dominant factor influencing the demand for a commodity is price. Yet the current lack of supply has kept the industry small-scale, resulting in few options and higher prices. Customers don’t want to buy products when prices are higher than similar products on the market.
In an earlier blog I explained the technology needed to increase the supply of hemp fiber utilizing green decortication. Not only would the supply of hemp increase, but the cost of processing would be lowered resulting in hemp which was cheaper and more competitive with other natural fibers. Lower prices will increase demand, allowing hemp to be utilized in greater applications such as textiles, composites, plastics, and the building industry.
Another component influencing the demand for a product is the cost of related goods. Flax is a good example. Like hemp, flax produces a bast fiber which is utilized in the manufacturing of linen fabrics. Linen textiles produced from flax are so similar to hemp that it is difficult to tell them apart without a lab test. While flax grows 3 feet in height, hemp can grow 15-20 feet tall, producing two to three times as much bast fiber per acre as flax and five times as much hurd.
Approximately 12 million acres of flax are grown throughout the world. This type of flax is mostly grown in northern Europe and Russia with the highest quality fabrics being produced in Ireland, Italy, and Belgium. There has been a growing demand for flax fiber over the past couple of years. At the same time, sanctions banning imports from Russia has decreased the supply. This has resulted in flax fiber increasing in price, and for the first time in modern history hemp fiber is now less expensive than flax fiber.
“This has resulted in flax fiber increasing in price, and for the first time in modern history hemp fiber is now less expensive than flax fiber.”
The opportunity exists to substitute hemp fiber for flax fiber in many applications. This can begin by blending hemp with flax fibers to lower the cost of linen, and as hemp becomes even cheaper, it will begin to replace flax as the fiber of choice for linen textiles and other uses.
The missing piece needed to get the hemp fiber industry off the ground
A question frequently asked is “When will we start growing hemp for fabric in the United States?” Hemp has been legal to grow since 2018 and has been successfully cultivated for CBD flower and grain. But not much has happened on the fiber front. What needs to happen to get the hemp fiber industry off the ground?
To be successful, farmers need to grow hemp purposely for fiber. Hemp grown for fiber provides better quality bast and hurd compared to hemp cultivated for flower or grain. Fiber hemp is planted at a dense rate of 75-100 pounds of seed per acre. This results in thinner stalks, finer fibers, and a greater yield. Fiber crops provide around eight to ten times the yield of bast and hurd compared to flower or grain crops. This crop is harvested just prior to flowering, resulting in higher value fiber with fewer lignins and pectins.
The main reason we are not seeing hemp grown for fiber is the limited processing equipment needed to harvest and decorticate the stalks. Converting hemp flower into concentrated CBD can be done in a small lab or even a kitchen. And harvesting and cleaning hemp seeds uses existing agricultural technology. But due to the lack of infrastructure for hemp fiber, farmers are not growing the acreage required to make hemp processing feasible.
The average yield of hemp bast fiber is about 1600 pounds per acre. Modern textile mills need to produce tens of thousand yards of fabric per day to be efficient and competitive. A small amount of hemp grown cannot justify all the machinery needed to harvest the crop, decorticate the stalk and process the fiber. This equipment alone would be in the millions of dollars. Much more hemp is needed to make this viable.
“Farmers don’t want to grow hemp until there are companies who can process the fiber. And processors don’t want to invest in equipment until there are enough farmers cultivating the plant.”
The hemp fiber industry is between a rock and a hard spot. Farmers don’t want to grow hemp until there are companies who can process the fiber. And processors don’t want to invest in equipment until there are enough farmers cultivating the plant.
“Fiber hemp needs to be harvested and decorticated at the same time while the plants are still green.”
To get hemp fiber into the market at a decent price, one main innovation needs to happen. Fiber hemp needs to be harvested and decorticated at the same time while the plants are still green. Green decortication refers to separating the bast from the hurd in the field while the plants are still growing and alive. Green hemp is easier to decorticate than dried hemp, resulting in a more complete separation of bast and hurd. And when the harvesting and decortication is done at the same time, the quality of the fibers are more homogeneous. Methods using water or dew retting are subject to variables such as temperature and humidity leading to fiber which is not consistent in quality.
Harvesting combined with green decortication will be cheaper and more practical providing several benefits:
It reduces the need to build expensive processing facilities.
It would allow hemp to be grown in more diverse areas.
Equipment can be shared among farmers during harvesting time.
Farmers will be able to sell the separated bast and hurd at a higher price than plain hemp stalks, resulting in a higher return for their crop.
This is the main hurdle to getting fiber hemp off the ground. No current machinery exists which can harvest and decorticate at the same time. Yet both processes are already being used with other crops. Hemp is easily harvested with a sickle bar. And a similar fiber crop jute is decorticated with existing machinery. The key is to combine both processes into one harvester. Once the machinery is in place, both fibers will be available to the various industries which use them. Farmers could sell the bast fiber to make yarns and textiles textiles while the hurd would be used for the building and composite industries. The raw materials will be competitive with similar fibers and the farmers would earn more money resulting in a win-win situation.
How the Hemp Industry is affected by international trade and shipping rates
You may be wondering why hemp fabrics aren’t made in the United States. The reason for this goes back to 1937 when the Marijuana Tax Act outlawed cannabis, making it basically impossible to possess and sell cannabis-derived products. These restrictions had prominent effects, one of them being the halt of the industrial hemp industry.
“It is more economical and environmentally friendly to transport products from China to Los Angeles overseas, than from Los Angeles to San Francisco by truck.”
In the late 20th century, fabric production costs increased in the United States, simultaneously there was an emergence of huge textile mills in developing countries. This led to companies sourcing raw materials and manufacturing overseas. Around 1992, hemp fabrics were imported into the United States from China and Europe, to be reintroduced to the American market.
While it may seem counterintuitive to ship items across the globe, It is more economical and environmentally friendly to transport products from China to Los Angeles overseas, than from Los Angeles to San Francisco by truck.
A rule of thumb for shipping: high value, low volume products are easily shipped across the globe, while low value, high volume products are restricted to local areas.
While hemp prohibition ended in 2018 on the federal level, the fiber industry has yet to materialize. While floral hemp doesn’t require large amounts of acreage to meet the demand, thousands more acres of fiber hemp need to be planted to get the industry started. The current situation puts the industry between a rock and a hard spot.
“Farmers don’t want to grow large amounts of hemp unless they have factories to buy and process the fiber. While companies don’t want to build factories unless there is a sufficient amount of raw materials to keep them in operation.”
Farmers don’t want to grow large amounts of hemp unless they have factories to buy and process the fiber. And companies don’t want to build factories unless there is a sufficient amount of raw materials to keep them in operation. The legalization of industrial hemp in the United States creates the opportunity for the industry to move forward. For example, high-quality hemp fiber and fabrics can be compressed into tight units. Therefore they can be shipped across the country and across the globe without much of an increase in price. The opportunity exists for farmers to grow hemp fiber in this country and export it to other countries that can transform them into fabrics. The fabrics can then be shipped back to the U.S., in whole or as finished products to be sold on the market. This is currently being done with cotton grown in the United States.
On the other hand, hemp cannot be grown solely for hurds since its value is too low. Products like hemp hurds, hemp insulation, or hemp boards are difficult to ship long distances while maintaining a competitive price. But by growing hemp for high-value fiber and grain, the lower value fiber and hurd may be used within the United States to produce hemp building materials. It creates a win/win situation where each country does what they do best, and free trade allows these items to be purchased around the globe. Free and fair trade will allow the hemp industry to grow and prosper.