Ah, Hemp. Hemp is naturally one of the most ecologically friendly fabrics and also the oldest. The Columbia History of the World states that the oldest relics of human industry are bits of hemp fabric discovered in tombs dating back to approximately 8,000 BC.
Hemp fiber is one of the strongest and most durable natural textile fibers. Not only is it strong, but it also holds its shape having one of the lowest percent elongation of any natural fiber. In fact, its combination of ruggedness and comfort were utilized by Levi Strauss as a lightweight duck canvas for the very first pair of jeans made in California. Furthermore hemp has the best ratio of heat capacity of all fibers giving it superior insulation properties. As a fabric, hemp provides all the warmth and softness of other natural textiles but with a superior durability seldom found in other materials. Natural organic hemp fiber ‘breathes’ and is biodegradable. Hemp blended with other fibers easily incorporate the desirable qualities of both textiles. When combined with the natural strength of hemp, the soft elasticity of cotton or the smooth texture of silk create a whole new genre of fashion design.
A fiber of a hundred uses besides fabrics, hemp is also used in the production of paper. The oldest piece of paper - over 2000 years old - was discovered in China and is made from hemp. Until 1883, between 75% and 90% of all paper in the world was made with hemp fiber. The Gutenberg bible (15th century), Lewis Carroll's Alice in Wonderland (19th century) and just about everything in between was printed on hemp paper. Thomas Jefferson wrote the early drafts of the Declaration of Independence on hemp paper produced in Holland. Jefferson grew hemp on his plantation as an industrial crop, selling the dried stalk to the U.S. Navy as outfitting material. George Washington also grew hemp, harvesting the fibrous seed for a variety of commercial uses including a skin lotion.
Other uses include feed for animals and for humans in veggie burgers, salad dressings, and pastas. Hemp seed is nutritious and contains more essential fatty acids than any other source, is second only to soybeans in complete protein (but is more digestible by humans), is high in B-vitamins, and is a good source of dietary fiber. Cosmetics manufacturers include hemp oil in makeup, skin lotions, and shampoo. In Europe, hemp is used in household cleaners as a natural alternative to harsher chemicals.
Hemp is a renewable resource which grows more quickly and easily than trees making hemp more cost effective than waiting decades for trees to grow to be used in man-made fiber production such as lyocell and rayon from wood pulps. The bark of the hemp stalk contains bast fibers, which are among the Earth's longest natural soft fibers and are also rich in cellulose. The cellulose and hemi-cellulose in its inner woody core are called hurds. Hemp fiber is longer, stronger, more absorbent and more insulative than cotton fiber.
Hemp produces more pulp per acre than timber on a sustainable basis, and can be used for every quality of paper. Hemp paper manufacturing can reduce wastewater contamination. Hemp's low lignin content reduces the need for acids used in pulping, and its creamy color lends itself to environmentally-friendly bleaching instead of harsh chlorine compounds. Less bleaching results in less dioxin and fewer chemical by-products. Hemp fiber paper resists decomposition, and does not yellow with age when an acid-free process is used. Hemp paper more than 1,500 years old has been found. Hemp paper can also be recycled more times than wood-based paper.
According to the Department of Energy, hemp is an excellent biomass fuel producer and the hydrocarbons in hemp can be processed into a wide range of biomass energy sources, from fuel pellets to liquid fuels and gas. Development of bio-fuels could significantly reduce our consumption of fossil fuels and nuclear power.
Hemp can be grown organically easily and hemp is most often grown without herbicides, fungicides or pesticides. Hemp is also a natural weed suppressor due to the fast growth of the plant’s canopy.
Eco-friendly hemp can replace most toxic petrochemical products. Research is being done to use hemp in manufacturing biodegradable plastic products: plant-based cellophane, recycled plastic mixed with hemp for injection-molded products, and resins made from the oil are just a few examples.
IS HEMP LEGAL? Yes. Industrial hemp products such as clothing and food stuffs are completely legal in the U.S. but the cultivation of industrial hemp is not. Even though hemp was used for centuries in this country to manufacture many personal and industrial products, the U.S. is the only industrialized nation in the world that does not recognize the value of industrial hemp and permit its production. Hemp sold in the United States comes primarily from China, Hungary, Thailand, Romania and Chile. Hemp is also legally cultivated in Australia, England, Canada and New Zealand.
Hemp suffers guilt by association because it is related to marijuana even though industrial hemp contains almost no THC, tetrahydrocannabinol – the psychoactive component. While marijuana typically contains between 3 and 20% THC, industrial hemp produces less than 0.3%. Someone smoking socks made from hemp might become nauseous but they would never become high.
USES FOR HEMP Hemp can be used to produce a very large variety of products from clothing to paper to building supplies to cars to fuels to food products to much, much more. Some people have called hemp the plant of 30,000 uses because it combines the utility of the soybean, the cotton plant and the Douglas Fir tree into one green package. Hemp is an environmental, renewable, reusable and recyclable resource.
- Hemp fabrics. Hemp grows well without herbicides, fungicides, or pesticides. The production of cotton, on the other hand, consumes almost half of the agricultural chemicals used on American crops. Hemp bast fibers are one of the longest natural soft fibers. They are longer, stronger, more absorbent, more mildew-resistant, and more insulative than cotton. This means that hemp will keep you warmer in winter and cooler in summer than cotton. Hemp is more effective at blocking the sun's harmful ultraviolet rays. The nature of hemp fibers makes them more absorbent to dyes, which coupled with hemp's ability to better screen out ultraviolet rays, means that hemp material is less prone to fading than cotton fabrics are. Like cotton, hemp can be made into a variety of fabrics, including high quality linen. When blended with materials such as cotton, linen, and silk, hemp provides a sturdier, longer lasting product, while maintaining quality and softness.
Hemp is environmentally friendly in many ways. It can displace the use of cotton, which requires massive amounts of chemicals harmful to people and the environment. The production of cotton consumes 50% of the pesticides sprayed in the entire world. Hemp has a deep root system that helps to prevent soil erosion, removes toxins, provides a disease break, and aerates the soil to the benefit of future crops.
- Biodegradable industrial products. Because hemp is rich in cellulose, research is being conducted into the use of hemp for the production of biodegradable plastic products. Plant based cellophane, recycled plastic mixed with hemp for injection-molded products, and resins made from hemp oil could one day be manufactured. BMW in an effort to make cars more recyclable, is using hemp materials in their automobiles. Hemp fibers are increasingly being used in industry as a substitute for fiberglass. The advantage of replacing fiberglass with hemp is that hemp is lighter, as strong or stronger, is biodegradable and is cheaper.
- Biomass fuels. Hemp is a high yield fiber crop, producing more biomass per acre than most other crops. As a result, the hydrocarbons in hemp could be used as a renewable, low polluting alternative to fossil fuels that is non-polluting to our atmosphere. Hemp is excellent in producing alternative fuels such as biodiesel and ethanol. Hemp could be processed into fuel pellets, liquid fuels, and gas, reducing our consumption of fossil fuels and nuclear power. Both the seed and the fiber can be used, though the process varies depending on what you use.
- Replacement for wood products. As a replacement for wood products, hemp offers many more environmentally friendly benefits. Hemp yields three to eight tons of fiber per acre, which is four times the yield of the average forest. Unlike wood, hemp is low in lignin, which means that hemp can be pulped using fewer chemicals. Many construction products now made out of wood could be made from hemp. Beams, studs, posts, oriented strand board, and medium density fiberboard made from hemp would be stronger and lighter because of hemp's long fibers. Washington State University produced hemp fiberboard that was found to be twice as strong as wood-based fiberboard. The replacement of wood fiber by hemp-based products can save forests for wildlife habitat, watersheds, recreational areas, oxygen production, and carbon removal, which reduces global warming.
- Paper. Hemp paper is of the highest quality, resists decomposition, and does not yellow as it ages when an acid-free process is used. It is for these reasons that hemp paper is used in Europe for bibles. A sample of hemp paper has been found that is more than 1500 years old. Only around 1850 did paper from wood pulp start to replace hemp. Trees were cheap, but now they are rapidly getting depleted. Over a period of 20 years one hectare (ha) of hemp can produce as much paper as four hectares of forest. Japan still imports much of its wood pulp from tropical rainforests which are being destroyed at an alarming rate. Hemp paper can be recycled many more times than wood-based paper. Hemp's natural creamy color eliminates the need for chlorine bleach, which prevents the dumping of extremely toxic dioxin into streams. Instead, hemp can be bleached using gentler hydrogen peroxide.
- Body Care Products. Hemp’s antimicrobial properties make it useful for cosmetics and body care products such as shampoos and hair conditioners, lotions, massage oils, salves, soaps, skin crèmes, sunscreen, and lip balm. The oil from hemp seeds has been known to cure dermatitis and other serious skin diseases.
- Pet Foods. Hemp provides a healthy protein for pets from dogs and cats to cows and horses to all varieties of birds and chickens.
- Detergents. The oil is also being made into a laundry detergent that biodegrades naturally in our water systems.
- Art supplies. Hemp is an excellent archival material, for use in paintings and books. Most famous paintings are painted with hemp oil on hemp linen. In ancient China the art of making paper from hemp and mulberry bark was guarded as a state secret, but eventually the knowledge found its way to Japan and also to Europe via the Arabs. In 1390 the first European mill processing hemp rags into paper was founded. In 1455 Gutenberg printed the first printed book in Europe on hemp paper. Washi, a traditional Japanese paper, was made from hemp and mulberry fiber. Nowadays hemp is virtually unavailable for this purpose though a limited supply of hemp paper has been manufactured in Tochigi recently. Hemp and mulberry paper are also used for ritual strips of paper decorations used at Shinto shrines. Japan imported the recipe for paper making from China where most paper still contains hemp today.
- Food products. A vast array of food products can be made from hemp seeds. They have exceptional nutritional value and are second only to soybeans as a source of complete vegetable protein. However, they are longer lasting and more digestible than soybeans. The main protein found in hempseed is edestin. Unlike soy, hemp doesn’t have to be cooked or fermented for it to be digestible.
VALUE OF HEMP IN FOOD PRODUCTS
Hemp seeds contain all eight essential amino acids in the correct proportions required by humans, including Omega-6 (LA- linolenic) and Omega 3 (ALA alpha linolenic). Hemp has a balance of three parts Omega-6 to Omega-3, very close to the body's nutritional requirements. As regulators, the LA and ALA fatty acids provide stability and control the movement of all substances in and out of our bodies' building blocks. Gamma Linolenic Acid (GLA), another essential amino acid found in hemp, also stimulates the production of eiconsanoids, which are hormone-type substances. For this reason, many women find hemp oil in their diets helps relieve pre-menstrual syndrome and extreme symptoms of menopause. Some of the other benefits of having all these Essential Fatty Acids in the diet include an increased metabolism, lower cholesterol, better digestion, general vigor, improved skin and hair condition, and a boosted immune system.
HEMP FIBERS AND FABRICS The textile material used to make hemp clothing comes from the long strands of bast fiber that make up the stalk of the hemp plant. The long bast fibers are the most desirable for the manufacturing of textile. They can be spun and woven into a fine, linen-like fabric. This fabric can then be used alone, or blended with cotton, linen, silk, or man-made fibers such as lycra and lyocell. Hemp fibers are mildew and microbe resistant, which make them valuable for the production of sails, tarps, awnings, carpets, and clothing.
When compared to other bast fibers such as flax, ramie and jute, hemp ranks second in fiber length, ultimate fiber length, aspect ratio, tenacity, tensile strength, and breaking length, and third in cellulose content.
Flax is the dominant bast fiber in North America. The following are the primary differences between hemp and flax:
- Hemp fibers can reach longer lengths although most processing methods and machinery reduce the lengths of hemp fiber. New processing techniques for hemp may be developed to enable fiber length to become an advantage in certain applications.
- Flax is reported to have a "farm odor" when used in making composite board whereas hemp exhibits little odor.
- A significant difference is the versatility and characteristics of hemp hurd verses flax shives. The hurd has a longer fiber than shives. This longer fiber is able to add strength to paper and perhaps other types of products.
- Hemp is colorless.
- Less processing is required to produce long line flax fiber of textile quality. Hemp is larger and the bonds are stronger to separate the fibers.
- Flax is thinner than hemp therefore retting is easier. This is an important issue and is a critical factor affecting the quality of fiber.
- Flax is preferred to hemp in the textile industry, even in geographic areas where there have no restrictions on growing hemp.
Hemp fabric is naturally more suitable to people with chemical sensitivities such as Multiple Chemical Sensitivities than cotton. Hemp grows well without herbicides, fungicides, or pesticides. The production of cotton, on the other hand, consumes almost half of the agricultural chemicals used on American crops. Hemp bast fibers are one of the longest natural soft fibers. They are longer, stronger, more absorbent, more mildew-resistant, and more insulative than cotton. This means that hemp will keep you warmer in winter and cooler in summer than cotton. Hemp is more effective at blocking the sun's harmful ultraviolet rays. The nature of hemp fibers makes them more absorbent to dyes, which coupled with hemp's ability to better screen out ultraviolet rays, means that hemp material is less prone to fading than cotton fabrics are. Like cotton, hemp can be made into a variety of fabrics, including high quality linen. When blended with materials such as cotton, linen, and silk, hemp provides a sturdier, longer lasting product, while maintaining quality and softness.
FROM FIELD TO FABRIC Hemp has demonstrated that it can have a significantly positive impact upon the environment and the lives of people. Let’s examine how friendly the processes are for converting hemp plants into fabric and garments. The major steps in taking hemp from the field to fabric fashions are:
- Growing. Hemp has been described as "Flax with attitude". It's quick growth -- germination to maturity takes between 80-120 days (depending on variety, latitude and field/climate factors) - to reach heights of up to 15' is one of hemp's most impressive features. On a summer day, some claim that you can almost see hemp growing. Unlike cotton, hemp grows in many climate zones. It does especially well in regions where corn is grown. The plant has a short growing season of three to four months. Hemp is grown densely packed with up to 150 plants per square meter so that tall plants containing long primary bast fibers will be produced. By the time they are ready to be harvested, the hemp plants have reached a height of two to four meters. Hemp requires no pesticides to aid in its growth, as it is naturally pest resistant. It has been known to reduce pests in future crops when grown in rotation. Hemp requires no herbicides because it is grown so densely that it smothers out other plants. Hemp also requires little or no fertilizer and it returns 60-70% of the nutrients it takes from the soil.
- Weed Control. Herbicides are not needed for growing hemp. Hemp grows very quickly and its dense foliage chokes out most weeds. Field choice, pre-seeding tillage, shallow seeding, and packing after seeding all help to ensure that the hemp stand will emerge quickly and uniformly to gain advantage over the weeds.
- Insect Control. Bertha armyworn (Mamestra configurata) may be a significant pest to industrial hemp. Bertha armyworm is a cyclical pest of canola and other crops in Canada. Other pests that have been observed include Lygus plant bugs, cutworms, and grasshoppers. Organic farming methods can be use to control these insect pests.
- Disease Control. Diseases that can attack hemp include Sclerotinia sclerotiorum and Botrytis cinerea. Wild mustard and volunteer canola, or adjacent canola stands can be the source of Sclerotinia stem rot infections. Adequate rotation with non-susceptible crops, ensuring seed free of disease organisms, and management of host species like wild mustard and volunteer canola are the key approaches to manage disease risk. The lower plant densities used for seed production should be less risky for sclerotinia than higher density plots for fiber production, but because fiber crops will be cut by mid-flowering the disease may be of less consequence.
- Harvesting. For hemp, there are two products to be harvested – the hemp fiber and the hemp seeds. The highest quality fiber is obtained by cutting at early to mid flowering. Mowers with the crimping rolls removed and round-balers may be suitable for low to medium quality end uses. The best approach for harvesting appears to be combining when shelling becomes evident and running the header cutter bar 4 to 5 feet above the ground. Care should be taken to avoid dehulling the seeds in the combine, since dehulled seed is more prone to spoilage or quality loss in storage. After combining, the remaining stalk material can be cut and baled. The mature stalk contains a coarse, low-grade fiber compared with stalk cut at early flowering, but is still marketable.
- Drying and Storage. Freshly threshed seeds may have an average moisture content of 16 - 20%. The moisture content at which hemp seeds/grain can be considered "dry" is not known precisely. Seeds should be dried to between 12% and 10%. Air flow through hemp grain should be relatively free. Because the grain may be tough when it is combined, drying should commence as soon as possible after harvest to ensure that quality remains high. Large fans, some with heaters, are used to dry the hemp seed grains.
- Grain Cleaning. Ultimately hemp grain seeds need to be cleaned to a rigorous standard for food processing. Conventional seed cleaning apparatus should be able to deal with most foreign material or weed seed problems. If a significant amount of green foreign material is present in the harvested grain, the grain should be pre-cleaned prior to storage to avoid spoilage. Some contracting companies may arrange to do the cleaning themselves.
- Grading. Grading standards have not been determined for hemp grain seeds. Buyers will be concerned about foreign material, seeds with adhering bracts, dehulled or otherwise damaged seeds, and off-type crop or weed seeds.
MANUFACTURING HEMP FABRIC
Because of its unique nature, hemp can easily be grown organically. In creating healthy, organic clothing, growing is only half the picture. Processing fiber into fabric and fabric into garments must also be done using processes that are healthy to the individual, the environment and the society. Hemp fabrics have been woven for at least 10,000 years.
The traditional methods have evolved during the centuries but the processes have remained friendly to the environment and to the wearer because they have remained mechanical rather than chemical. Many hemp fabric manufacturers, especially in Eastern European countries such as Romania and Hungary, use the traditional mechanical process that utilize modern machinery specially designed for hemp processing.
Modern methods are being developed which rely upon chemical rather than mechanical processes because they are faster, less labor-intensive and therefore less expensive. The hunger for profits undermines the health of people, the ecology and the environment.
We will examine the basic processes and how they are performed under modern chemical methods and under traditional organic methods. The basic processes involved in creating hemp fabric for garments are:
- Separating the fibers;
- Spinning and weaving these fibers into yarn;
- Cleaning and softening;
- Dyeing and finishing;
SEPARATING FIBERS. Retting begins the process of separating the long bast fibers from the non-fiber portions of the bark and is completed during the decortication and hackling steps.
Chemical Methods. Modern chemical hemp processing makes use of enzymes, chemicals and even ultrasound to rett, or separate, the long bast fibers from the plant for spinning into yarns for fabrics.
Some hemp fiber manufacturers in China use modern physical-chemical methods which create a cotton-like short fiber. This creates a short fiber hemp called "cottonized" hemp or "flock" hemp. But the quality of the resulting yarns still needs improvement, especially in the area of long-term wash-and-wear resistance. This may be due to chemical processes removing most of the natural binders lignin and pectin from the hemp fibers.
Organic Methods. Traditional hemp processing of plants into yarn for fabrics relies on natural and mechanical processes to separate the long fibers from the plant for spinning into yarns. Two traditional types of retting are field and water retting. Basically, retting is the microbial decay of pectin, the substance that glues the fiber to the woody core of the hemp stem.
In traditional field retting, the process is bacterial, aided by dew or rain. Field retting will involve chopping of the stalk into lengths of 12-18 in., turning of the windrow at several-day intervals, and baling when retted and dry. Field retting takes 14 to 21 days to complete depending upon the weather. Ecologically acceptable water retting should be conducted near a sewage treatment plant to treat the waste water.
Water retting produces a more uniform and higher quality fiber but the process is time consuming and costly and can pollute the body of water being used for the process.
Another process being developed is green retting or mechanical retting. This process uses a machine at the field to mechanically separate the fiber from the hurd. Machinery for this process is currently being designed and tested by various companies throughout the world.
In Eastern Europe, the raw fiber is separated by traditional methods of water retting, breaking, scutching, and hackling. This produces the high quality long fiber that is first spun on special long fiber spinning equipment (up to 14 Nm) and then woven.
SPINNING & WEAVING. Spinning takes the hemp fibers and spins them together to produce a long continuous strand of yarn. This yarn is then used to weave or knit the fabric used in hemp garments and textile products. The spinning process is essentially the same for hemp that has been processes using chemical methods or using organic, chemical-free methods. After all, spinning is spinning.
What is different in the spinning process between hemp fibers processed using chemical methods and fibers from organic methods is generally the length of the hemp fiber and the spinning machines that are required to spin the long fiber organic hemp and the short fiber, chemically processed hemp. Textile manufacturers who simply want to get on the hemp bandwagon as cheaply as possible are more likely to also use chemical methods to process their hemp fibers.
When the hemp fabric is washed and shrunk, the weave will naturally close up. This is in direct proportion to the degree of shrinkage obtained. In practical terms, this means that identically woven fabrics may appear different if one of them has been washed, dyed, bleached, or shrunk.
Chemical Methods. Unlike long fiber hemp, short fiber “cottonized” hemp created by chemical processing can be spun and finished on slightly modified cotton or wool processing equipment, so that the existing and cost effective infrastructures for the processing of cotton and wool could be used. This allows textile manufacturers to begin processing hemp fabrics quickly and with a lower cost to enter this new market. Several textile equipment manufacturers are currently conducting spinning trials using short fiber hemp on modern rotor spinning machines.
Organic Methods. Today’s fiber spinning machines have been designed for the shorter fibers found in cotton and wool. Because hemp retted using traditional organic methods retains the long fibers in hemp, specialized spinning machinery is required to process the long fibers into spun yarn. The additional expense of the specialized spinning machines and the greater cost to operate, have discouraged existing textile manufacturers to expand their operations into the production of long fiber hemp yarns.
CLEANING AND SOFTENING. Among those familiar with hemp fabric from years ago, hemp has a reputation as being stiff and even abrasive to the skin. The naturally long and strong fibers created fabric that was stiffer and heavier. Hemp textile manufacturers have sought ways to improve the softness of hemp fabric.
Chemical Methods. Chemical processing uses heavy caustic sodas and acid rinses to pulp, clean and soften the fiber. Unfortunately this strips the fiber of much of its rich character and strength and produces hazardous, environmentally-destructive waste. Solvents are used to scour and clean the fabrics.
Organic Methods. Ecologically-minded hemp textile manufacturers have been researching and developing new methods and machinery to produce chemical-free, organic hemp fabrics that are soft to the skin and yet retain the exceptional durability of hemp. ECOLUTION®, an environmentally-friendly grower and manufacturer of hemp products that is based in Romania, has pioneered many of the new methods for producing superior hemp garments and products. They have accomplished this by refining the hackling stage of their combing technology and the banding stage in the fiber preparation.
Because of its low lignin content, hemp can be pulped using less chemicals than with wood. Its natural brightness can obviate the need to use chlorine bleach, which means no extremely toxic dioxin being dumped into streams. A kinder and gentler chemistry using hydrogen peroxide rather than chlorine dixoide is possible with hemp fibers. All scouring and cleaning agents are biodegradable, rather than solvent –based.
DYEING & FINISHING. The impact on the environment by the process of dyeing textiles vary greatly around the world. Many developing countries have no regulations regarding the methods of dyeing, the types of dyes used, and the disposal of waste. In the United States, and especially California, environmental laws regulate the types of dyes and dyeing methods used by commercial dye houses.
There is a lot of confusion regarding the dyeing of textiles and what is to be considered "environmental". When determining the measure of harm done to the environment by the dyeing process, one must take into account three elements:
- The actual dye used and whether or not it has toxic properties.
- The method of dyeing and how much energy is required.
- How much dye gets into the fabric and the method of disposal of excess dye and chemicals.
The handling of waste is probably the biggest factor to determine how detrimental the process is to the environment. Is the excess waste filtered and neutralized before it is put down a drain? Or is it just dumped into a river? Once again, environmental laws play an important role with developing countries usually using the cheapest and most convenient method of disposal.
Hemp garments can be dyed or “natural” color. Natural is not really a color; it is simply the absence of dyes and is basically the natural beige color of the hemp fibers after processing. This is why hemp garments that are a “natural” color can vary greatly in color.
Chemical Methods. Chlorine is often used to clean and prepare the garments for dyeing and then synthetic dyes are used. Synthetic dyes are produced in a laboratory and synthesized from other chemicals. Some synthetic dyes contain heavy metals and other elements that react negatively if released in the environment. Newer synthetic dyes used in U.S. and Europe tend to have less harmful elements. The method of dyeing also plays a factor. Harmful chemicals may be added to the dye bath to help the dye molecules bind to the fibers of the fabric. Also the amount of energy used to run the dye machine in the form of mechanical action and heat vary greatly from company to company and country to country.
Mercerization is sometimes used to prepare garments for dyeing because it increases luster, strength and an affinity to accept dyes. Mercerization is a treatment that swells the fibers of yarns by immersing the yarns in sodium hydroxide, which is a caustic soda, and then neutralizing them with acid.
Organic Methods. For hemp to be considered organic, the finishing of the fabrics is done largely without the use of synthetic chemicals. If their use becomes necessary only those chemicals which meet strict ecological criteria are employed. New ecologically safe technologies in dyeing and finishing have been developed such as air finishing technology that uses strong blasts of compressed air to soften hemp fabric in the finishing stage.
Sometimes a starch sizing might be used before dyeing and finishing. Sizing is a generic term for compounds applied to fabrics to improve their smoothness, abrasion resistance, stiffness, strength, weight of luster. Starch is generally used in organic processing and enzymes are often used to desize natural sizing. Hydrogen peroxide bleach is used to prepare the fabric for light or bright color dyes.
Natural dyes can be made from plants, earth clays, and even insects. Many people mistakenly believe that fabrics dyed using natural dyes will be less harmful to the ecosystem than conventional dyeing methods, but this is not always the case. The process of extracting pigment molecules from nature may require more energy and harmful chemicals than synthesizing them in the lab. In some dyes, the actual pigment molecules are the same, whether they originated in nature or the lab.
Low impact and fiber-reactive dyes are made from natural components that are water soluble with a fixation ratio of at least 70%. They have no heavy metal content. The low impact dye process reclaims heat used in the dyeing process and has on-site water filtration to cleanup waste waters used in the dyeing process. Any additives used in the dye bath must be biodegradable.
The following eco-friendly process might be used to finish the hemp fabric. Note: these processes might also be used on other natural fabrics.
- Tentering: Process for holding a fabric to desired width during drying. A tenter frame machine holds the fabric firmly at the edges by pins or clips as it advances through a heated chamber. This is generally the final step in finishing, giving the fabric its finished appearance.
- Sanforized: A trademarked control standard of shrinkage performance. A method of compressive shrinkage involving feeding the fabric between a stretched blanket and a heated shoe. When the blanket is allowed to retract, the cloth is physically forced to comply. Leaves fabrics with a residual shrinkage of not more than one percent.
- Compacting: A permanent treatment by which heat and pressure shrink a fabric so that resulting texture is crepey/crinkled and bulky.
- Calendering: Fabric is passed between heated cylinders under pressure to produce a flat, glossy, smooth, high luster surface.
- Steam Chamber: Stabilizes the colors of dyes after printing and dyeing processes. Process where steam is passed through fabric. This partially shrinks and conditions the fabrics when applied, especially on wovens.
- Heat Shrinkage: Improves shrinkage resistance and shape retention of fabric and often other desirable properties, such as wrinkle resistance by means of either dry or moist heat.
- Singeing: Burning off protruding fibers from fabric by passing over flame or heated plates. Imparts the smooth surface necessary for printing and clear finishes.
- Brushing: Utilizes multiple brushes or other abrading elements to raise fiber ends thus producing a nap on surface of fabric.
- Sanding or Sueding: Process by which fabric passes over rapidly revolving rollers covered with abrasive paper.
- Napping: Raising the surface fibers of fabric by means of passage over rapidly revolving cylinders covered with metal points/fine wire brushes or teasel (plant) burrs.
- Enzyme Washing: The use of an enzyme (organic catalyst used to speed up a chemical reaction) to produce stone washed effects on fabrics. This process id less damaging to fabrics than actual stone washing and produces a highly desirable soft hand.
- Biopolishing: Where cellulose (any group of enzymes that degrade cellulose) enzymes hydrolyze the fiber surfaces. This treatment improves hand, reduces fuzz and pilling and gives clearer finish. Biopolishing agents should adhere to the following requirements to be considered environmental:
- Softeners used are biodegradable.
- No Formaldehyde based resins.
- No undisclosed chemical finishes.
- No acid wash/No stone wash.
ECOLOGY OF HEMP.
Hemp is more eco-friendly by its very nature and it can be used for a very wide variety of
products - from foodstuffs to bio-fuels to construction materials to paper products to textiles. And new uses are continually unfolding as we come to better understand the potential of hemp. Industrial hemp advocates propose using hemp as a replacement for wood and cotton because it offers products of comparable or superior quality while reducing or eliminating the ecologically negative characteristics involved in their processing.
Comparing Hemp with Wood. As a replacement for wood products, hemp offers many environmentally friendly benefits. Hemp achieves better land utilization as it yields three to eight tons of fiber per acre, which is four times the yield of the average forest. An acre of hemp produces 4.1 times as much paper as an acre of trees. Hemp can also be harvested every year while trees take 20 years or more to grow to harvest. Since hemp builds topsoil, it can be grown on the same acre of land year after year. Many acres of forest could be saved by industrial cultivation of hemp for paper alone. The replacement of wood fiber by hemp-based products can save forests for wildlife habitat, watersheds, recreational areas, oxygen production, and carbon sequestration to help in reducing global warming.
Many construction products now made out of wood could be made from hemp. Beams, studs, posts, oriented strand board, and medium density fiberboard made from hemp would be stronger and lighter because of hemp's long fibers. Hemp fiberboard has been manufactured that is twice as strong as wood-based fiberboard.
Unlike wood, hemp is low in lignin, which means that hemp can be pulped using fewer chemicals. Hemp can also be bleached using a gentle hydrogen peroxide rather than toxic chlorine compounds and dioxins which are generated as a by-product of paper production. Many of these toxic chemical waste products from wood pollute our streams, rivers and lakes. The discharge of heavy metals and toxins like sulfuric acid and dioxin could be reduced by 60 to 80 percent by making the switch to hemp pulp.
Hemp can be made into fine quality paper. The long fibers in hemp allow hemp paper to be recycled several times more than wood-based paper. Hemp paper is of the highest quality, resists decomposition, and does not yellow as it ages when an acid-free process is used. Hemp paper is more durable and will last for ages. For these reasons, hemp paper is often used in Europe for bibles.
Comparing Industrial Hemp with Cotton. Hemp has few natural predators and it grows well without herbicides, fungicides, or pesticides. The production of cotton, on the other hand, consumes about 25% of all pesticides used on American crops. Some of these chemicals are among the most toxic classified by the U.S. Environmental Protection Agency. In developing countries, where regulations are less stringent, the amount of herbicides and insecticides and their toxicity is often greater than those used in the U.S. on cotton crops.
Industrial hemp is also a very land efficient crop. On a per acre basis, hemp yields 250% more fiber than cotton and 600% more fiber than flax without the need for toxic chemical pesticides and fertilizers.
Hemp bast fibers are one of the longest natural soft fibers. They are longer and stronger than cotton with eight times the tensile strength and four times the durability of cotton. Hemp fibers are also more absorbent, more mildew-resistant, and more insulative than cotton. This means that hemp will keep you warmer in winter and cooler in summer than cotton. Hemp is more effective at blocking the sun's harmful ultraviolet rays.
The nature of hemp fibers makes them more absorbent to dyes, which coupled with hemp's ability to better screen out ultraviolet rays, means that hemp material is less prone to fading than cotton fabrics. Like cotton, hemp can be made into a variety of fabrics, including high quality linen. When blended with materials such as cotton, linen, and silk, hemp provides a sturdier, longer lasting product, while maintaining quality and softness.
LAND USE AND HEMP. Hemp has a deep root system that helps to prevent soil erosion, removes toxins, provides a disease break, and aerates the soil to the benefit of future crops. Hemp grows well in a variety of climates and soil types. It is naturally resistant to most pests, precluding the need for pesticides. It grows tightly spaced, out-competing any weeds, so herbicides are not necessary. It also leaves a weed-free field for a following crop.
The cultivation of industrial hemp also combats the growing problem of topsoil erosion. In the U.S., more than five billion tons of precious agricultural topsoil is lost each year due to erosion. Hemp is the ideal farm crop to counter this loss. The fine root systems and the long tap roots of hemp plants will penetrate the soil for three to seven feet, helping to anchor and protect soil from runoff and erosion.
Hemp builds and replenishes topsoil and subsoil structures. Hemp plants shed their leaves throughout the growing season, adding rich organic matter to the topsoil and helping it retain moisture which allows hemp to be more drought-resistant. Hemp leaves the soil in excellent condition for any succeeding crop, especially when weeds may otherwise be troublesome.
INDUSTRIAL HEMP FOR RENEWABLE ENERGY. As a renewable resource from living plants hemp does not contribute to the greenhouse effect. The growing plants absorb as much CO2 as will later be released when oil or other plant matter is burnt. Unlike fossil fuels such as oil, coal, natural gas or nuclear fuels, hemp could supply us with raw materials for thousands of years, without ever changing our climate and without producing waste that remains radioactive for millions of years.
Hemp is a high yield fiber crop, producing more biomass per acre than most other crops. As a result, the hydrocarbons in hemp could be used as a renewable, low polluting alternative to fossil fuels. Hemp could be processed into fuel pellets, liquid fuels, and gas, reducing our consumption of fossil fuels and nuclear power. Biomass can be converted into virtually every form of energy used, including methanol to power automobiles. Since methanol is a cleaner fuel than petro-based fuels, this would lead to reduced auto emissions. Corn is the most popular source of biomass today; but hemp can yield up to eight times as much methanol per acre as corn.
Unlike fossil fuel, biomass comes from living plants that continue to remove carbon dioxide from the atmosphere through photosynthesis. With plant heights reaching 15' or more, hemp creates a lot of oxygen and captures high amounts of carbon from the atmosphere. Hemp fields could become very important in addressing issues of planetary climate change.
When hemp is grown for biomass, CO2 is taken in and metabolized by the plants, generating oxygen in the process. When the biomass is burned as fuel, the CO2 is released back into the air. This maintains a balanced CO2 cycle. By contrast, burning fossil fuels introduces back into the atmosphere carbon that has been "out of circulation" for millions of years, and provides no mechanism for re-absorption.
On a global scale, hemp is perhaps the only plant capable of producing sufficient biomass to provide an alternative to fossil fuels. As a biomass fuel resource, hemp could stop a host of damaging effects associated with fossil fuels: strip mining, oil spills, acid rain and sulfur-based smog.
Biodiesel can be made from domestically produced, renewable oilseed crops such as hemp. Hemp stems are 80% hurds (pulp byproduct after the hemp fiber is removed from the plant). Hemp hurds are 77% cellulose a primary chemical feed stock (industrial raw material) used in the production of chemicals, plastics, and fibers. Biodiesel is the name for a variety of ester based oxygenated fuels made from hemp oil, other vegetable oils or animal fats. The concept of using vegetable oil as an engine fuel dates back to 1895 when Dr. Rudolf Diesel developed the first diesel engine to run on vegetable oil. Diesel demonstrated his engine at the World Exhibition in Paris in 1900 using peanut oil as fuel.
Biodiesel is the only alternative fuel that runs in any conventional, unmodified diesel engine. It can be stored anywhere that petroleum diesel fuel is stored. Biodiesel is safe to handle and transport because it is as biodegradable as sugar, 10 times less toxic than table salt, and has a high flashpoint of about 300 F compared to petroleum diesel fuel, which has a flash point of 125 F. Biodiesel can be made from domestically produced, renewable oilseed crops such as hemp. Biodiesel is a proven fuel with over 30 million successful US road miles, and over 20 years of use in Europe. When burned in a diesel engine, biodiesel replaces the exhaust odor of petroleum diesel with the pleasant smell of hemp, popcorn or french fries. Biodiesel is the only alternative fuel in the US to complete EPA Tier I Health Effects Testing under section 211(b) of the Clean Air Act, which provide the most thorough inventory of environmental and human health effects attributes that current technology will allow.
Biodiesel is 11% oxygen by weight and contains no sulfur. The use of biodiesel can extend the life of diesel engines because it is more lubricating than petroleum diesel fuel, while fuel consumption, auto ignition, power output, and engine torque are relatively unaffected by biodiesel.
The Congressional Budget Office, Department of Defense, US Department of Agriculture, and others have determined that biodiesel is the low cost alternative fuel option for fleets to meet requirements of the Energy Policy Act.
Industrial hemp has many wonderful properties and uses that can help our planet and people achieve a healthier and more natural and sustainable existence ... our governments just have to get past the unreasonable fears and phobias and ingrained self-interests of some of our large industries and their lobbyists.