What Is Microfiber?: Basic Introduction
What Is Microfiber?: Basic Introduction
What Is Microfiber?: Basic Introduction
Basic introduction
Microfiber commonly refers to any fiber with strand less than 1 denier. Textile synthetic microfibers such as polyester microfibers have a diameter of about 10 microns or less. While most microfibers are of synthetic origin, asbestos can be considered as natural mineral microfibers since the fibers width is less than 1 micron. Synthetic microfibers have been developed in Japan in the early 1970's by Dr. Miyoshi Okamoto. Despite their great potential it took some years before they find various applications. It was later improved by Dr. Toyohiko Hikota who designed the first non-woven fabric, named Ultrasuede, which production was started in 1989 by the US Company Dupont de Nemours. Microfiber use in textile industry consecutively expanded. Though different polymers can be used to produce microfibers, polyester and nylon are the most employed and are often mixed together to obtain specific properties. Composite fibers can also be split to produce thinner strands that can be less than 0.2 denier. A microfiber's diameter often measures half of a silk fiber and allows producing very lightweight fabrics with excellent draping qualities, wearing comfort and luxurious appearance. When woven appropriately microfiber fabrics have even more properties: good isolation, impermeability, breathing ability, wrinkle-resistance, stain-resistance, easy washability.
Technical Description
According to its design and engineering, microfibers can be very different from each other. Focusing on the most common cleaning textile microfiber, the bicomponent polyester (PET) -polyamide (PA, Nylon) pie wedge microfiber, here is short explanation of its physical properties:
+ Water absorption
Liquids are subject to the effect of surface tension which is the result of different intra molecular forces, and especially the Van der Waals forces. All liquids' molecules undergo cohesive forces between them which confers them this liquid physical state. However, molecules at the surface are subject to stronger cohesive forces than molecules down into the liquid since there are no other cohesive forces coming from above to compensate those cohesive forces coming from beneath the surface. Being bound to each other more strongly, surface molecules act as a film, making it more difficult to move an object through the surface than moving it when completely submersed. Water tension is what can make a needle float in a glass of water or what allows water striders to move on the surface of a pond. Surface tension contributes to what is called the capillary effect, which takes effect when wicking away some liquid and can be observed when putting a dry sponge on a water puddle . Technically speaking, it occurs when the adhesive intermolecular forces between a liquid and another surface (in our previous example, respectively water and sponge) are stronger than the cohesive intermolecular forces of the liquid - In other words it is a mere power struggle! When adhering to the sponge surface, water molecules, because of their surface tension, stick together. Besides, because of the constant motion of liquid's molecules, new water molecules are consistently getting in touch with the sponge surface, progressing further on it... until the sponge is completely soaked. In some materials, such as a vertical glass tube, water is being pulled up until the weight of the lifted quantity, which causes a superior gravitational force, overcome the intermolecular forces of surface tension. The narrower the tube, the higher water can be drawn into it since a smaller mass of water is exposed to the surface allowing adhesive and cohesive intermolecular forces to combine and overcome gravity. Some materials which are water-repellent, such as Teflon, can prevent the capillary action. In that case the cohesive intermolecular forces of water are stronger than the adhesive forces with the Teflon surface, which prevent water from sticking to the surface . To sum up, capillary effect's efficiency depends on the kind of the surface material and on the available surface in a given volume: the more the surface of a hydrophilic material available in a limited volume, the more efficient should be the capillary effect. Sponge remains the best example in this respect.
Why are microfibers absorbent?
Cleaning microfibers are engineered in such a way as to make them very sensitive to the capillary effect. The action of splitting microfibers is a clincher as it releases the polyamide star shaped core of the fiber, which is rather hydrophilic, while multiplying the number of strands available on a same volume. It thus proportionally increases the total added surface of all the fibers available and hence enhances the sorption properties of the microfiber fabric. Weaving patterns are also important for that purpose as a very tightly woven polyester microfiber fabric will at first prevent water from soaking in since polyester is more water-repellent (which makes it efficient for clothing). Cleaning mops are thus woven with specific patterns that allow a high exposition of the fibers, especially the polyamide core, to the surface in order to maximize absorption . The capillary action is also mechanically increased by the scrubbing movements during cleaning. On average, a microfiber mop can retain up to 8 times its weight in water. Once inside the microfibers, water will be distributed quite fairly between fibers since polyester, which generally constitutes most of the fibers, is rather hydrophobic and won't accumulate much water molecules on its surface. This property of PET microfibers prevent the fabric from soaking (unless completely submerged) and make it is easier to dry since water on the fibers' surface evaporates more quickly. Doing so, it also prevents the growth of bacteria inside the fabric. Generally,moisture regain of polyester is around 0,4%, polyamide around 4,5% and cotton around 7%. When sweeping a wet surface, microfibers will absorb most of the liquid, but it will also spread some along the surface in a very thin layer, which, in case of water, evaporates almost immediately.
+ Dust trapping
Wetting a surface provokes an association of water and dust particles while wiping it with a cleaning microfiber cloth achieves to absorb the liquid and trap the dusts inside the fibers. There again, surface tension of water is involved in retaining the dust particles and make them stick to the fibers' surface. Those particles are, in turn, trapped between
the strands of the microfiber. While using dry cleaning microfiber fabrics
Static electricity is one of the first electrical effects to have been studied. Ancient Greeks discovered that rubbing some materials against each other could make them attractive to small particles. This effect is explained by an imbalance thus created in the amounts of positive and negative charges found within the surface of an object. Static electricity occurs when two object with an opposed charge are brought close to each other so as to create an electric field. This electric field is responsible to many properties and can be compared, to some extent, to a magnetic field. The bigger the gap between the two opposite charges, the more static electricity. This gap is measured in volts and often involves high voltage. When created by human activity, static electricity can range up to several thousands of volts. Everyday life has a broad range of electrostatic manifestations, from the small discharge one can get while gripping a doorknob to the phenomenon of lighting during a storm. Static electricity accumulated while putting two insulated surfaces into contact is known as triboelectric charging and depends on different parameters. The more surfaces are put into contact, the more they accumulate a charge. In this respect rubbing allows a repeated contact with few movements and further increases the voltage. According to the materials, the charge accumulated will be either positive or negative, whereas other materials do not accumulate charges at all. Triboelectric series list materials according to their charging polarity and capacity:
POSITIVE CHARGE
Dry Human skin Leather Rabbit Fur Glass Quartz Human hair Nylon Wool Lead Fur Lead Silk Aluminum Paper
NEGATIVE CHARGE
Wood Amber Hard rubber Nickel, Copper Brass, Silver Gold, Platinum Polyester Saran Wrap Polyurethane Polyethylene Polypropylene Vinyl (PVC) Silicon n Teflo
The ability for a material to acquire a positive or a negative charge tallies with its ability to lose or gain electrons. Concretely speaking, when putting two surfaces into contact, some chemical bonds are created and when surfaces are separated, bonds rupture tends to leave imbalanced charge behind, as electrons will move from one surface to another according to the material involved. The surface gaining electrons will acquire a negative charge whereas the surface losing electron will acquire a positive charge. Being insulated from the rest of its environment, generally by the air, the charged object can recover its neutrality if brought close enough to something with an excess opposite charge or to a neutral conductor. The charge can also dissipate after time especially if there is some humidity in the surrounding air. Incidentally, when there is a high degree of humidity in the atmosphere, electrostatic phenomenon are much more seldom since the water particles in the air act as a conductor and neutralize the excess charges on the surfaces.
What's in it for electrostatic microfiber?
Static electricity is the key behind this somehow magical effect: when fully efficient, a charged microfiber cloth do not even need to make contact with dust, it just attracts them from where they lie. Microfibers are made of polymers that have interesting triboelectric properties: polyester and nylon. When using a microfiber mop to sweep the floor, the fibers are rubbed between them and with the soil surface. Polyester fibers acquire a positive charge while nylon fibers acquire a negative charge, creating an efficient electric field. The charged mop will then attract small particles of dust through electrostatic induction, a by-effect that modify the charge within the dust particles. Split microfibers have very interesting electrostatic properties since nylon fibers are released amongst polyester fibers and their respective surfaces are in direct contact. Moreover the total added surface of all the fibers available being considerably increased, weeping movements will consecutively enhance the contact between fibers and the floor, and thus the electrostatic potential. Note that wet microfiber will lose its static electricity efficiency since water is rather conductive and when spread on the surface of the fiber it prevents the concentration of electric charges. In this regard, the low
moisture regain of polyester is a favorable to its electrostatic properties.
Grease/fat absorption
The molecular composition of polyester and nylon make them highly lipophilic . It means that fatty substances adhere to their surfaces. In fact both polyester and nylon are originally made of oil products! Once again split microfibers while offering a wider available surface can scoop up fatty substances much more efficiently than other fibers. Fat stay on the surface of the fibers until the cloth is laundered.
Cross section of microfiber and cotton threads. Principle of action, illustrated with the movement to the right. Microfiber leaves no residue, contrary to cotton.
Microfiber products used for consumer cleaning are generally constructed from split conjugated fibers of polyester and polyamide. Microfiber used for commercial cleaning products also include many products constructed of 100% polyester microfiber. Fabrics made with microfibers are exceptionally soft and hold their shape well. When high-quality microfiber is combined with the right knitting process, it creates an extremely effective cleaning material. This material can hold up to seven times its weight in water. Microfiber products have exceptional ability to absorb oils, and are not hard enough to scratch even paintwork unless they have retained grit or hard particles from previous use.
Microfiber is widely used by car detailers to handle tasks such as removing wax from paintwork, quick detailing, cleaning interior, cleaning glass, and drying. Due to their fine fibers which leave no lint or dust, microfiber towels are used by car detailers and enthusiasts in a similar manner to a chamois leather.
Microfiber is used in many professional cleaning applications, for example in mops and cleaning cloths. Although microfiber mops cost more than non-microfiber mops, they may be more economical because they last longer and [9][10] require less effort to use. Microfiber textiles designed for cleaning clean on a microscopic scale. According to tests using microfiber materials to clean a surface leads to reducing the number of bacteria by 99%, whereas a conventional cleaning material [11] reduces this number only by 33%. Microfiber cleaning tools also absorb fat and grease and [citation needed] their electrostatic properties give them a high dust-attracting power . Microfiber cloths are used to clean photographic lenses as they absorb oily matter without being abrasive or [12] leaving a residue, and are sold by major manufacturers such as Sinar, Nikon andCanon. Small microfiber cleaning cloths are commonly sold for cleaning computer screens andeyeglasses. Microfiber is unsuitable for some cleaning applications as it accumulates dust, debris, and particles. Sensitive surfaces (such as all high-tech coated surfaces e.g. CRT, LCD and plasma screens) can easily be damaged by a microfiber cloth if it has picked up grit or other abrasive particles during use. The cloth itself is generally safer to use on these surfaces than other cloths, particularly as it requires no cleaning fluid. One way to minimize the risk of damage to flat surfaces is to use a flat, non-rugged microfiber cloth, as these tend to be less prone to retaining grit. Cleaning textiles made of microfiber must only be washed in regular washing detergent, not oily, self-softening, soap-based detergents. Fabric softener must not be used. The oils in the softener and self-softening detergents will clog up the fibers and make them less effective until the oils are washed out.
Sourced from:
http://en.wikipedia.org/wiki/Microfiber
Microfiber has the excellent wicking properties. That is, the microfiber material will absorb moisture and oils
rather than allow them to set on the surface of the material. This wicking moisture property makes microfiber ideal for such things as footballs and basketballs, as the sweat from the players hands will not make the ball slippery and harder to hold. Microfibers are also used for various types of cloth where absorption of water is desirable. For instance, cleaning cloths for home dusting, cleaning glass, and detailing cars are often made of microfiber material. The microfiber cloths also leave behind no residue of lint or dust, which makes the material ideal for waxing a car. However, it is important to note that microfiber material will pick up dust and lint and absorb it. This means that it is a good ideal to wash the microfiber after each use, so that there will be no residue to be deposited the next time you dust or wash windows with the cloth. Microfiber is often used in other textile applications, such as tablecloths, sheer draperies and curtains. The stain repelling ability of the microfiber blend in these types of products makes them very attractive to many homeowners, as well as restaurants and other types of businesses that prefer to use materials that are both good looking and serviceable. During the middle twentieth century, the manufacture of synthetic fibers began to expand into new areas. One of the breakthroughs of the era was to take the sludge that was left over after oil had been refined and turn it into a synthetic fiber that could be used in upholstery. The process of refining this waste product yielded a substance known as polypropylene, which could in turn be processed into a thin olefin fiber. Olefin fibers were ideal to use in
the production of car upholstery, home and office carpeting, and even some draperies. Olefin fibers caught on in a big way during the 1970s, with such companies as Hercules, Inc. of Wilmington, Delaware producing their own branded form of olefin fiber, which was dubbed Herculon. Continued experimentation allowed for the use of polypropylene to develop an extremely fine fiber that was less than the one-denier standard of the time. Referred to as microfiber, this extremely thin but surprisingly resilient fiber could be used for a number of textile applications that the broader
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