THAIPM4A811blog: March 2013

Katrin‘s assignment

I chose 5 related terminologies for the Matelial knowledge assignment:

The material- Beta cloth

The fibre- Spandex, Alpaca, Pashmina

Test of pilling resistance- video

Beta Cloth

Beta cloth is a type of fireproof silica fiber cloth used in the manufacture of Apollo/Skylab A7L space suits and in other specialized applications.

Beta cloth consists of fine woven silica fiber, similar to fiberglass. The resulting fabric will not burn, and will melt only at temperatures exceeding 650 °C. To reduce its tendency to crease or tear when manipulated, and to increase durability, the fibers may be coated with Teflon.

Beta cloth was developed by a Manned Spacecraft Center team led by Frederick S. Dawn and including Matthew I. Radofsky working with the Dow-Corning Company. It was implemented in NASA space suits after the deadly 1967 Apollo 1 launch pad fire, in which the astronauts' nylon suits burned through. The fire-resistant Beta cloth was among changes to make the Apollo spacecraft and systems safer in the event of a similar situation.

Source: en.wikipedia.org/wiki/Beta_cloth

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930015285_1993015285.pdf

Spandex

Spandex or elastane is a synthetic fiber known for its exceptional elasticity. It is strong, but less durable than its major non-synthetic competitor, natural latex. It is a polyurethane-polyurea copolymer that was invented in 1959 by chemists C. L. Sandquist and Joseph Shivers at DuPont's Benger Laboratory in Waynesboro, Virginia. When first introduced, it revolutionized many areas of the clothing industry.
The name "spandex" is an anagram of the word "expands".^[1] It is the preferred name in North America; in continental Europe it is referred to by variants of "elastane", i.e. elasthanne (France), elastan (Germany), elastano (Spain and Portugal), elastam (Italy) and Elasthaan (Holland), and is known in the UK, Ireland, Argentina, Australia and New Zealand primarily as Lycra. Brand names for spandex include Lycra (made by Koch subsidiary Invista, previously a part of DuPont), Elaspan (also Invista), Acepora (Taekwang), Creora (Hyosung), ROICA and Dorlastan (Asahi Kasei), Linel (Fillattice), and ESPA (Toyobo).

Spandex fibers are produced in four different ways: melt extrusion, reaction spinning, solution dry spinning, and solution wet spinning. All of these methods include the initial step of reacting monomers to produce a prepolymer. Once the prepolymer is formed, it is reacted further in various ways and drawn out to make the fibers. The solution dry spinning method is used to produce over 94.5% of the world's spandex fibers.

Solution dry spinning

Step 1: The first step is to produce the prepolymer. This is done by mixing a macroglycol with a diisocyanate monomer. The two compounds are mixed in a reaction vessel to produce a prepolymer. A typical ratio of glycol to diisocyanate is 1:2

Step 2: The prepolymer is further reacted with an equal amount of diamine. This reaction is known as chain extension reaction. The resulting solution is diluted with a solvent (DMAc) to produce the spinning solution. The solvent helps make the solution thinner and more easily handled, and then it can be pumped into the fibre production cell.

Step 3: The spinning solution is pumped into a cylindrical spinning cell where it is cured and converted into fibres. In this cell, the polymer solution is forced through a metal plate called a spinneret. This causes the solution to be aligned in strands of liquid polymer. As the strands pass through the cell, they are heated in the presence of a nitrogen and solvent gas. This process causes the liquid polymer to react chemically and form solid strands.

Step 4: As the fibres exit the cell, an amount of solid strands are bundled together to produce the desired thickness. Each fibre of spandex is made up of many smaller individual fibres that adhere to one another due to the natural stickiness of their surface.

Step 5: The resulting fibres are then treated with a finishing agent which can be magnesium stearate or another polymer. This treatment prevents the fibres' sticking together and aids in textile manufacture. The fibres are then transferred through a series of rollers onto a spool.
Major spandex fibre uses

Apparel and clothing articles where stretch is desired, generally for comfort and fit, such as:

athletic, aerobic, and exercise apparel

belts

bra straps and side panels

cycling jerseys and shorts

dance belts worn by male ballet dancers and others

gloves

hosiery

leggings

netball bodysuits

orthopaedic braces

cross country race suits

ski pants

skinny jeans

socks

swimsuits/bathing suits

underwear

Compression garments such as:

foundation garments

motion capture suits

Shaped garments such as:

bra cups

support hose

women's volleyball shorts

wrestling singlets

Home furnishings, such as microbead pillows

For clothing, spandex is usually mixed with cotton or polyester, and accounts for a small percentage of the final fabric, which therefore retains most of the look and feel of the other fibers. In North America it is rare in men's clothing, but prevalent in women's. An estimated 80% of clothing sold in the United States contained spandex in 2010.

Source: en.wikipedia.org/wiki/Spandex
http://www.fibersource.com/f-tutor/spandex.htm

Alpaca fiber

Alpaca fleece is the natural fiber harvested from an alpaca. It is light or heavy in weight, depending on how it is spun. It is a soft, durable, luxurious and silky natural fiber. While similar to sheep’s wool, it is warmer, not prickly, and has no lanolin, which makes it hypoallergenic. Alpaca is naturally water-repellent and difficult to ignite Huacaya, an alpaca that grows soft spongy fiber, has natural crimp, thus making a naturally elastic yarn well-suited for knitting. Suri has far less crimp and thus is a better fit for woven goods. The designer Armani has used Suri alpaca to fashion men's and women's suits. Alpaca fleece is made into various products, from very simple and inexpensive garments made by the aboriginal communities to sophisticated, industrially made and expensive products such as suits. In the United States, groups of smaller alpaca breeders have banded together to create "fiber co-ops," to make the manufacture of alpaca fiber products less expensive.

The preparing, carding, spinning, weaving and finishing process of alpaca is very similar to the process used for wool.

Fiber structure

Alpaca fiber is similar in structure to sheep wool fiber. Its softness comes from the small diameter of the fiber, similar to merino wool. Its glossiness is due to low height of the individual fiber scales compared to sheep wool. Alpaca fibers have a higher tensile strength than wool fibers. In processing, slivers lack fiber cohesion and single alpaca rovings lack strength. Blend these together and the durability is increased several times over. More twisting is necessary, especially in Suri, and this can reduce a yarn's softness.

The alpaca has a very fine and light fleece. It does not retain water, is thermal even when wet and can resist solar radiation effectively. These characteristics guarantee the animals a permanent and appropriate coat to protect against extreme changes of temperature^. This fiber offers the same protection to humans.

Medullation

Medullated fibers are fibers with a central core, which may be continuous, interrupted, or fragmented. Here, the cortical cells that make up the walls of the fiber, are wrapped around a medulla, or core, that is made up of another type of cell (called medullary cells). Later, these cells may contract or disappear, forming air pockets which assist insulation.

Medullation can be an objectionable trait. Medullated fibers can take less dye, standing out in the finished garment, and are weaker. The proportion of medullated fibers is higher in the coarser, unwanted guard hairs: there is less or no medullation in the finer, lower micrometer fibers^.These undesirable fibers are easy to see and give a garment a hairy appearance. Quality alpaca products should be free from these medullated fibers.

Quality

Good quality alpaca fiber is approximately 18 to 25 micrometers in diameter.While breeders report fiber can sell for US$2 to 4 per ounce, the world wholesale price for processed, spun alpaca “tops” is only between about $10 to $24/kg (according to quality), i.e. about $0.28 to $0.68 per oz Finer fleeces, ones with a smaller diameter, are preferred, so are more expensive. As an alpaca gets older, the diameter of the fibers gets thicker, between 1 µm and 5 µm per year. This is sometimes caused by overfeeding; as excess nutrients are converted to (thicker) fiber rather than to fat.

Elite alpaca breeders in the United States are attempting to breed animals with fleece that does not degrade in quality as the animals age. They are looking for lingering fineness (fiber diameters remaining under 20 micrometers) for aging animals. It is believed this lingering fineness is heritable and thus can be improved more and more over time.

As with all fleece-producing animals, quality varies from animal to animal, and some alpacas produce fiber which is less than ideal. Fiber and conformation are the two most important factors in determining an alpaca's value.

Alpacas come in 22 natural colors, with more than 300 shades from a true-blue black through browns-black, browns, fawns, white, silver-greys, and rose-greys However, white is predominant. because of selective breeding: the white fiber can be dyed in the largest ranges of colors. In South America, the preference is for white, as they generally have better fleece than the darker-colored animals. The demand for darker fiber sprung up in the United States and elsewhere, though, to reintroduce the colors, but the quality of the darker fiber has decreased slightly. Breeders have been diligently working on breeding dark animals with exceptional fiber, and much progress has been made over the last few years

Dyeing

Before dyeing, the alpaca fiber must go through other stages:

Selection of wool, according to color, size and quality of fiber

"Escarminado", removal of grass, dirt, thorns, and other impurities

Washing, to remove all the dirt and grease

Spinning

Once the fiber is clean, it is possible to begin the process of dyeing.

Natural dyeing: (recipe used by Andean artisans): To dye 1 kg of alpaca wool with cochinilla (natural dye),

Boil 5 liters of water in an aluminum can with 100 g of cochinilla for an hour.

Sift and put the fiber in the water.

Boil again for an hour and add 50 lemons cut in halves.

Then take out the wool and hang for drying.

Note: For dyeing with another natural dye (native plants), add 2 kg of the products to the water and boil.

Woman who makes Alpaca yarn- YouTube video

Uses

Alpaca fiber is used for many purposes, including making clothing such as hats, mitts, scarves, gloves, and jumpers. Rugs and toys can also be made from alpaca fiber

Source: http://en.wikipedia.org/wiki/Alpaca_fiber International Alpaca Association <http://www.aia.org.pe/aia.html?32

Pashmina

The word pashmina comes from the ancient Persian word “pashm” which means wool. Nepal is one of, if not the, prime exporter of pashmina products all over the world. In fact, the pashmina itself is a native and indigenous product of Nepal. Cultivated from a rare breed of goats found only at 12,000 to around 14,500 feet above sea level in the Himalayan regions of Tibet, Nepal and Central Asia, most notably Mongolia, the pashmina is considered the best cashmere on earth. The goats from where the pashmina comes are called the “capra hircus.” In order for these goats to protect themselves from the harsh temperate climate, the goats have developed short, thin and shiny inner coats on their underbelly over time. These short inner hairs have proven to be the best natural insulation in the world. When these goats shed their hair during spring, these are collected to form the pashmina. In fact, the Persian word for wool refers precisely to the inner coat of the “capra hircus.”

Pashmina fiber

Pashmina is incomparable to the other fibers found anywhere else. The pashmina has been treasured throughout Asia and the Middle East, and its no wonder that the West and the rest of the world have finally caught on the craze. Not only does it provide warmth, but it also comes in a dazzling array of colors and can be extremely versatile. It is strong yet flexible, it is not heavy on the body, and while it provides maximum warmth, it still manages to be a soft, luxurious and comfortable wrap for both daytime and evening wear.

Items made from Pashmina

Aside from shawls, the pashmina also comes in a variety of forms such as pashmina stoles, pashmina mufflers, pashmina scarves, sweaters and blankets, all handwoven by the traditional weavers of Kathmandu valley. These exquisite products also come in a variety of sizes, patterns and qualities and all sold at a fairly reasonable price.

End uses of Pashmina

A pashmina is usually worn as a wrap.The colors of pashmina that are particularly fashionable and in demand according to distributors are shades of purple, from a pale lilac to a deep violet shade of grape. Some other trends include pashminas that are dotted with ethnic embroidery and pleats. Many other women opt for the classic look, and choose all-time favorite colors such as pink, yellow, white and jet black. Because of its versatility, the pashmina can also be worn over a jacket or as a muffler around the neck or simply just draped over the shoulders and the chest. Indeed women of all ages, shape and sizes, from mothers to Hollywood celebrities, from students to business executives, all seek the elegance, sheer comfort and practicality of beautifully woven pashmina.

Sources: Clothing technology; www.pashminainternational.com http://en.wikipedia.org/wiki/Pashmina_fiber

Conclusion

From a purchasing point of view, it is essential to know about the fibers and fabrics, their properties, advantages and disadvantages. Moreover, dealing with supplier often we will have only description of a garmetn and its materials, so we should be able to know what the description stands for in regards with quality levels and so on. Also, it is essential to know and understand the different terminology and to consider the different peremeters, e.g Yard- Meter and so on. Personally, I liked the idea about making a blog and video, so we can be more creative and expose in different way information and knowledge.

Video- Pilling resistance

THAIPM4A811blog

Friday, 15 March 2013

Katrin's assignment