Cashmere Deep Dive - The material
So soft, so delicate, so light - the raw material from which the cashmere yarn is made is the cuddly down hair of the cashmere goat, which grows under the longer, covering contour hair and is only developed under extreme weather conditions.
The longer and finer the fiber of the raw material, the thinner and correspondingly more valuable the cashmere thread spun from it is. Cashmere fiber is one of the natural fibers of animal origin. Animal fibers are primarily divided into wool (sheep), fine hair (llama, alpaca, mohair, angora, cashmere, camel), coarse hair (cow, goat, horse) and silk.
In order to adapt to environmental conditions, all species with hair follicles - including humans - have developed fibers over the course of millions of years to protect them from the weather. This can be hair or fur or fur - a natural, survival-important adaptation that regulates temperatures, absorbs sun rays or has tactile functions.
A four-season fiber
In general, the goat's primary hair is one of the oldest natural textile materials in the world and is referred to as hair yarn.
The secondary duvet fluff of cashmere goat is considered one of the finest hair yarns ever. The cashmere fiber is an extremely complicated protein fiber (protein) with special properties: thanks to its special surface, it is extremely light, flexible and pliable, expandable in volume and elastic like rubber. The tear strength is 2.5 grams.
Like the fiber of sheep's wool, the cashmere fiber is also able to absorb moisture in the form of water vapor and thereby absorb up to 30 percent of its own weight.
Cashmere is breathable, insulates well against heat and cold and is extremely warm. This is why it is also referred to as a “four-season fiber”. Cashmere is antistatic and absorbs little dust from the air. Its natural protective layer makes it largely resistant to stains. The fiber is non-flammable, 100 percent biodegradable and able to adapt optimally to the environment - all properties that make cashmere so unique and ideal for textile use
Structure and construction
The morphological structure of cashmere fiber is similar to the structure of fine wool. The fibers can be imagined as long, hollow horny threads made of α-keratin, which essentially consist of highly cross-linked polypeptide chains. Like human hair, the color of the fiber is determined by the pigment melanin. Roughly speaking, the fiber is made up of three layers: the outer cuticle, which is made up of keratinized, flat and overlapping cells that are oriented towards the tip of the hair like a pine cone.
This layer surrounds the fiber trunk (cortex), which consists of polymer spindle cells and forms the majority of the hair, around 80 percent. Inside is the medulla, which is usually hollow and filled with air.
In contrast to the coarse cuticle layer of a sheep's wool fiber, which has a high, roof-tile-like appearance, the cuticle of the cashmere fiber is hardly scaled, its ladder-like scale cells are smooth and even. Seen under the microscope, cashmere hair is reminiscent of slightly curved bamboo canes. The low scale height of the downy hair fiber is the reason for the soft feel and pleasant grip of the raw material.
The coarse guard hair of the cashmere goat, on the other hand, has similar external characteristics to wool, i.e. it is scaly and stronger.
Four essential parameters determine the quality of the cashmere fiber: length, cross section, color and proportion of guard hairs remaining in the raw material. The individual hair can be up to 75 millimeters long. As a rule, the length of a very high-quality fiber is between 38 and 42 millimeters. The fineness or the cross-sectional dimension is given in microns or millimeters (a micron is one thousandth of a millimeter, 1 μm = 0.001 mm). The finer the hair, the higher the quality. The diameter of particularly fine hair varies between 14 and 18 microns, which is approximately one-sixth the diameter of a human hair. 5 Fine merino wool is around 19 microns, normal virgin wool is 22 microns.
Color is also a quality-determining feature. Natural white cashmere is the most precious. It is so sought after because it is the easiest to process and dye - it resembles a precious piece of particularly high value. In China, where cashmere is often referred to as “soft gold” or “white gold,” there are more cashmere goats with white hair than anywhere else. The delivery share of pure white cashmere raw material here is 60 percent, whereas Iran, for example, supplies “only” 20 percent white raw material. The remaining portion is either light brown, gray or dark brown.
Overall, however, the population of white cashmere goats is small. Pied goats with different colored hair such as brown, light gray or black are in the majority. They developed over the centuries through the natural genetic crossing process. Nevertheless, the lighter the fibers, the more expensive the raw material. If white duvet hair is mixed with other colored hair when combing out or if it is packaged without taking the colors into account, its value decreases because it is very time-consuming to sort the raw material according to color afterwards. The practice of bleaching dark raw fleece using the white bleaching process does occur, but always means a loss of quality. Similar to human hair that is bleached or dyed, cashmere is extremely sensitive. The elasticity disappears, the softness is lost, the grip becomes noticeably harder, it appears brittle and stressed. Therefore, chemical treatments should be avoided if possible
The proportion of guard hair in the cleaned raw material is also crucial for the evaluation of cashmere. The longer primary hairs cannot be 100 percent removed either during the production of the duvet or during the manufacturing process. Depending on the use, a remaining proportion of 0.1 to 0.5 percent is the rule. Particularly valuable yarn should not contain more than 0.1 percent guard hair. A yarn of the highest quality is called cashmere two ply28, ideally white, extremely fine (14 μm - 17 μm), at least 32 millimeters long and is twisted from two cashmere threads. Therefore it is stronger and more elastic than the so-called one-ply yarn. 1 kilogram of cashmere two ply28 produces a yarn 28 kilometers long.
In order to check the impeccable quality of their goods, reputable cashmere traders and producers base themselves on guidelines that correspond to internationally established standards. Accordingly, one speaks of genuine pure cashmere if the fiber cross section does not exceed the maximum upper limit of 19 microns. On the one hand, a coefficient of variation of 24 percent is permitted, and on the other hand, a tolerance value of three percent of hair with a maximum diameter of 30 microns.
100 percent cashmere
The market value of cashmere depends on the quality checked. The prices for raw materials vary and range from around 60 to 150 euros per kilogram. Pure white, 32 millimeter long cashmere hair from China currently costs around 125 US dollars, making it one of the most expensive animal hairs in the world.
Because Merino wool is up to ten times cheaper in comparison, the textile industry has a great interest in clearly identifying and declaring textiles made from relevant animal hair - and in recognizing incorrectly labeled raw materials and goods. According to the European Textile Labeling Regulation, the label “100%”, “Pure” or “Whole” may only be given to textiles that consist exclusively of one fiber. The manufacturing tolerance mark here is three percent by weight of foreign fibers, provided that this proportion is justified by the fact that it is technically unavoidable with good manufacturing practice and is not the result of systematic addition.
A product declared as “100% cashmere” is therefore of the highest quality and made from pure cashmere hair. If “Cashmere” is to appear on a product label, cashmere must be guaranteed to be at least 85 percent. A sweater with cashmere content must have a minimum cashmere fiber content of 14.5 percent. Despite these regulations, it still happens that cashmere is declared incorrectly. The price difference between cashmere and other animal fibers (alpaca, angora, mohair, yak hair, camel hair) is enormous and tempts people to put animal hair mixtures into circulation and label them as pure cashmere. The German Wool Institute (DWI) estimates that at least 25 percent of cashmere goods worldwide are incorrectly declared - a figure that unsettles consumers and puts the industry in a negative light, especially since there are no applicable seals of quality or institutions that take on control functions.
Alpaca fibers treated with chlorine, sheep's wool coated with silicone particles, camel hair trimmed with chemical softeners - attempts at deception of this kind serve the purpose of preparing hair or wool smoother, thinner and softer in order to make it feel like cashmere. Tricks that often go unnoticed because laypeople and even experts often cannot tell what materials are involved. Imitations cannot be distinguished from cashmere with the naked eye
Retail chains and designer labels use the possibility of scientific fiber testing. This is offered by several internationally operating laboratories that are accredited worldwide by the International Wool Textile Organization (IWTO) and the Cashmere and Camel Hair Manufactures Institute (CCMI). They have the expertise and experience to subject fibers to specific measurements. Essentially, four internationally standardized provenance procedures are used to identify and test and determine the actual fiber content of a product:
Light microscopy (LM), scanning electron microscopy (SEM, scanning electron microscopy), protein and DNA analysis. Light microscopy is an optical – historically relevant – method that has been used since the 1950s. It makes internal structures and pigmentation of the fiber visible and is based on the recognition of the cuticle layer of the fiber, which has been enlarged a thousand times. In the scanning electron microscope process, so-called “topographic fingerprints” on the surface provide information about the optical properties of the fiber. The most common method today has been scientifically researched and modified since the early 1980s. The finest fiber snippets are moved under the microscope following a grid system. Parameters such as scale pattern and number of scales per micrometer of fiber length, fiber diameter and structure of the fiber surface are registered and recognized.
The most important criterion in which cashmere fibers differ from sheep fibers is the height of the scale edges. The scanning electron microscope method is able to calculate and evaluate these dimensions. Protein analysis is a physicochemical method that is based on the fact that different proteins occur in different abundances in different species. It separates and filters proteins and thus provides clues to the genetic origin of animal hair. As a carrier of genetic information, DNA is suitable for the clear identification of a species. It occurs in hair in sufficient quantity and quality. The analysis compares the DNA cashmere sample to be identified with relevant comparison samples and checks possible matches.