It is apparent that there are a lot of misconceptions, tales and myths about the performance characteristics between both nylon types. Often achieved by good marketing stories woven to "prove" anything. We'd like to share this educative article to all end-user's, architects, designers and purchasers.
Are There Real Differences Between Type 6 and 6.6 Nylons?
By Carey Mitchell (Director of Technical Services at Shaw Industries. Dalton, US)
Nylon can be synthesized in several ways, each beginning with different precursors and ending with different end products, such as nylon 6, nylon 6.6; nylon 11, nylon 6.10; nylon 6-T (Nomex); with carpet we are concerned only with types 6 and 6.6. The numeral in the type designation indicates the number of carbon atoms in the raw materials. Type 6 begins with caprolactam, which contains 6 carbons, and 6,6 with hexamethylene diamine and adipic acid. There is no technical basis for the belief that more carbon atoms impart better properties as continuous chains are formed.
The result is a polymer that can be heat set to retain twist, and contains "dye sites," or amine groups along the polymer chain. These groups are capable of forming strong chemical bonds with dyestuffs, giving excellent colorfastness characteristics. Like other synthetic fibers, abrasion resistance is high. Type 6 has a slightly more open molecular structure, dyestuffs to penetrate more easily.
While some small differences do exist between the two fibers, these must be examined in terms of whether they are practical differences. Tensile strength, for instance, is a very important consideration in rope, but is irrelevant with carpet because high tensile strength is unimportant; in fact, if it is too high, piling occurs on loop pile carpets because any fuzzing oft the pile surface will not break away. On the other hand, a nice marketing story can be woven around small differences in tensile strength.
It is important to understand that differences can be evaluated objectively only when the samples are produced identically, from yarn processing onward through manufacturing. Otherwise process differences have been shown to exert greater influences on various properties than fiber differences. Several examples of this phenomenon are given below.
There is a common misconception that T-6 nylon soils faster than T-6.6 because T-6 has more dye sites. This is based somewhat on the erroneous assumption that dye sites are holes or "pits" in the fiber surface where dye particles lodge themselves, and that soil particles immediately jump in also. Viewing the surface of both types through a microscope shows both to have perfectly smooth surfaces and neither can be distinguished from the other. More importantly, the number of "dye sites," technically known as amine groups, are not peculiar to either type, but are controlled during polymerization to achieve a specific purpose, i.e., some T-6.6 has far more amine groups than T-6! An amine or "dye site" is simply a chemically active point on the polymer chain where dye molecule attaches - the important point is that these are inside the fiber, not on the surface, and dye molecules must migrate into the fiber in order to attach.
This myth has been further fueled by a two-decade-old tale about DuPont's square cross section contract carpet fiber, where supposedly the "V" between the lobes of trilobal fibers holds oil more than the square cross section of Antron fiber. If this were true, DuPont would certainly not market square cross section fiber for cut piles!
Conversely, another tale that made the rounds in the marketplace years ago suggested that DuPont's and BASF's contract fibers with holes running lengthwise were produced that way to enable blowing air into the fiber to make it cheaper to produce! The purpose of cross section modification and hollow cores is to impart light diffusion and physical properties. Carefully controlled tests, where all processes and construction parameters were identical, have demonstrated clearly that fiber type has no impact on soiling rate. The rate at which a carpet soils is determined by many factors, such as residual fiber finish, topical anti soil treatments, on-location treatments, cleaning residues, etc.
Today's soil resistant treatments are applied on both types more uniformly and perform better than in previous years.
The majority of "stains" involved in complaints turn out to be soiling of some sort. An excellent example is a spill of soft drink or coffee with sugar, where the sugar becomes sticky and turns into a very effective shoe cleaner. The resultant area shows the classic explosion pattern and is often mistaken for a stain, but it can he easily and quickly removed using plain water. Permanent staining, on the other hand, occurs when a colored material penetrates into the fiber and cannot be removed. The best example of this is beverages colored with red food coloring the - food and beverage industry knows this as FD&C Red Dye #40 (Food, Drug and Cosmetic). The carpet industry knows this material as Acid Red 40 because it is used to dye carpet. Not surprising that it is difficult to remove.
Comparative testing of samples processed identically with stain resist shows no difference in stain resistance between the two nylons. While small differences exist between the fibers not treated with stain resist, the gap is smaller than the differences between the same fiber heat set by different systems, thus another example of process differences exerting greater influence than fiber differences.
Appearance retention, or "wear," can be assessed in many ways, but the only reliable method is to have real people walk on carpet samples under controlled conditions. When identical samples of each fiber type are constructed, dyed and finished under identical conditions, from yam formation forward, no difference is detected when tested simultaneously. In many cases where differences have been alleged, the samples were selected from inventory, with no knowledge of processing or controls - it is impossible to make valid determinations under such circumstances.
Various attributes have been cited as being important to carpet appearance retention such as fiber hardness, the complexity of the polymer molecule (number of carbon atoms), resilience, etc. The truth again is that, even if these differences did exist, design and process differences would overshadow them to the point that they would not be discernible.
The hardness issue has been debated for many years; it might be a real issue if the debate were about fiber wearing away through abrasion rather than a change in the carpet appearance. The truth is that all synthetic fibers are sufficiently hard that they simply do not wear away, even under the heaviest traffic. Abrasive wear warranties have made this something of an issue, but since these warranties are obsolete in the marketplace, fiber hardness becomes an issue only in comparing synthetic fibers against wool.
Twist has always been the most important factor in appearance retention, followed by pile weight, density, fiber (polyester, nylon, polypropylene), pile height, gauge, stitch count, although the relative order of importance changes depending on construction. It has not been possible within this list to find differences between nylon types, indicating that it is an unimportant issue in the overall picture of carpet performance.
Colorfastness is not an all-encompassing term, but must be addressed in terms of a specific insult to the fiber dye stuff combination. Carpets are exposed to many indignities, including sunlight, water, detergents, atmospheric gasses, foot traffic, etc., and a carpet's resistance to any of these must be assessed separately; the challenge is to obtain the best balance of these properties.
During the '60s and early '70s, disperse dyes were commonly used in residential and commercial carpet. Type 6 nylon's more open molecular structure allows disperse dyes to move about more than type 6.6 - the bottom line is that although there is a difference in colorfastness between the fibers, colorfastness suffers when disperse dyes are used with either fiber. The industry prudently moved away from disperse dyes in the mid- to late-'70s.
Colorfastness against sunlight is the most obvious area of concern in that more carpets are exposed to sunlight than to other insults. When carpets produced identically using acid dyes are tested for colorfastness against light, the results are generally identical.
Colorfastness against atmospheric contaminant gasses is of significant concern in areas where humidity is very high year 'round. These gasses are ozone, all of the oxides of nitrogen (NOx) and sulfur dioxide. All are oxidizers and are capable of destroying dye stuffs. Ozone has been most often blamed for complaints; it is a very active form of oxygen, but only becomes problematic when humidity exceeds about 95-90 %for long periods. Type 6 nylon has been considered more susceptible over the years. The reason for this goes back to the more open molecular structure, where dye molecules are in dynamic equilibrium and are thus capable of migrating to the fiber surface to replace those destroyed by oxidation. The advent of stain resist technology has rendered the difference moot with comparably treated samples T-6 often outperforming T-6.6. The stain resist prevents this mobility by penetrating the fiber and blocking movement; because it penetrates more easily and deeper into T-6 (stain resist chemicals reside just under the surface of the fiber), it is more effective. This was an unexpected benefit of the treatment.
Colorfastness against water, whether detergent or flooding, is largely determined by dyestuff selection rather than fiber type. Some dyestuffs are capable of producing limited depths of color; when this limit is exceeded in an attempt to make darker shades, bleeding often occurs. This is remedied by switching to a dyestuff that can produce darker shades without overloading the fiber.
All of the above comments apply to dyed carpets; those colored by pigments (solution dyed) are generally immune to these problems.
Some minor differences exist between the two types of nylon. When examined critically in the perspective of overall carpet performance, it becomes very apparent that these differences are of no consequence in real world terms. Carpet performance hinges on many factors of varying importance, but nylon type differences are so far over overshadowed by the others that they are near the bottom of the list. Carpet purchasers should be keenly aware that marketing stories can be woven to "prove" anything and that the issues must be considered objectively and in perspective.
(By Carey Mitchell is Director of Technical Services at Shaw Industries. Dalton, Georgia, US)
Dubai, United Arab Emirates
A day to day inside of flawed thinking in our business.
Floors need to be maintained for many reasons: appearance, contractual requirements, deterioration, hygiene and safety (listed alphabetically rather than in order of importance). The frequency and extent of maintenance should be determined by the usage and design of the floors as mush as, if not more than, the cost of the maintenance. Here floor maintenance has been divided into surface care and longer term maintenance issues.
Regular cleaning is obviously necessary to keep the appearance and hygiene of the floor to an acceptable standard. There are many inputs into any cleaning regime; the flooring materials manufacture’s recommendations; the cleaning materials manufacturer’s recommendations; the cleaning contractor’s specified procedure (perhaps using yet another cleaning materials with still further recommendations); the actual cleaning procedure; and lastly the clients/floor owners requirements.
Between all of these there is a host of opportunities for misunderstandings and omissions that may result in ineffective or uneconomic cleaning, with a variety of consequences.
Dirt can damage floors in many ways depending on what it is. Most ‘dirt’ consists of grit particles of sand-like materials that derive from wind blown soils and building sites. These are hard and abrasive and will scratch and wear away most floor surfaces if left to be trodden underfoot for too long.
Hard floors like vitrified tiles will cope with this better than terracotta, but a vinyl will quickly be reduced to a mass of scratches which can not be brought back to a normal sheen.
Another component of dirt is organic matter, which may be decaying vegetable matter blown around with the soil, dropped food particles of all sorts, human skin flakes, hairs from humans and animals, and a variety of other things that we all try to avoid mentioning (let alone treading in). These provide food sources for bacteria which themselves excrete chemicals that can attack cement grouts, terrazzo tiles, plastics, rubber and flooring adhesives.
For example, saliva remaining in chewing gum contains enzymes designed to begin destroying a wide range of organic materials; if left on a sheet flooring material in warm conditions for some time, who is to say what damage will be done to the surface at that spot? Scuff marks from shoes contain complex man-made organic chemicals which generally do not decay by bacterial action and which may be partly fused to a surface due to the friction heating when the scuff occurred.
None of the preceding circumstances can really be avoided except in special situations and even then not always. It is therefore a sensible thing to ensure that the floor is designed to cope with the worst of the likely conditions rather than the average conditions. By definition on average half the conditions will be worse than the floor is intended to deal with.
Those responsible for floor maintenance need to define what is the minimum necessary to properly clean a floor. This itself begs the question what is ‘properly clean’ and what does ‘properly’ imply?
For example, is a floor properly cleaned if it has the accumulations of dirt frequently seen in corners: surely these locations would be dealt with routinely with special equipment if necessary? Such accumulations would be unacceptable in a hospital; why then are they apparently acceptable in shopping malls, train station concourses, offices or warehouses?
‘Properly’ clean implies that the floor is put back into the condition that it was designed to be in, assuming the designers got it right in the first place, ‘Condition’ might include surface appearance, slip resistance, surface texture, light reflectance, or colour. How or whether this is ever achieved is rarely known: follow-up procedures seem to be undertaken only in the event of problems or accidents.
Apart from cleaning, floors need to be maintained to prevent or to repair deterioration.
Prevention maintenance may be part of a specification, or it may come about through on-site observation. Ideally the former is a better method. The use of anti-dusting treatments on concrete floors or regrouting of tiling and terrazzo, and the use of strippable dressings on sheet flooring are procedures that, if carried out at the right time, will prolong the life of a floor. It could be argued that proper entrance matting is also preventative maintenance as it can prevent dirt and moisture from reaching and damaging the floor.
Changes from the original use of a building can put unexpected stress on a floor which manifests itself by an increased need for maintenance. Deterioration to the extent of requiring areas of floor to be closed off to allow remedial works is not only damaging to the image of a shopping mall, but can have cost implications if trade to the shops suffers. If they were not anticipated by the designer of the floor, heavily laded, hard wheeled delivery pallets can be very damaging both the vinyl in a shop and tiling or screeds in delivery areas.
This is a special case of floor maintenance and in these litigious days it is in everyone’s interest to keep floors safe. Some 35% of all accidents are slipping and tripping and enormous sums of money are paid out annually by insurers and property owners in compensation. Inspection of floors for tripping hazards should be carried out regularly and a diary kept as evidence. Slipping is easier to predict, in that moisture on a floor will almost always cause people and vehicles to slip.
Entrance matting and quick responses to spillage’s are standard ways of dealing with this in enclosed areas, but care is needed to guard against condensation on the floor when warming a cold building. People rushing into a mall first thing in the morning are unlikely to see a fine wet mist on a cold tiled floor.
All floor materials wear and some will polish and become smoother as time goes on. There is no data on the rate at which this occurs so there is a real risk that as most floors are only classified as marginally safe in the wet when new, they will deteriorate to become dangerously slippery. Tests can show the conditions of the floor and treatments are available as remedial procedures. Repeated treatments are often necessary.
In my experience defects arise through poor specification, poor workmanship, incorrect programming of work and only occasionally defective materials.
Price is often used to cut the specification to the bone and it is true that you get what you pay for. The consequences of using cheap wall tiles are considerably less than using cheap floor tiles – it also depends what aspect of them has been made cheaper. This should be thought about by clients as well as designers and contractors, in the context of replacement at some later date. Poor workmanship is often associated with incorrect spreading of the adhesives and late application of the flooring into it. This can also be exacerbated by commercial pressures and the shortage of craftsmen who really understand what they are doing.
Flooring is often one of the last processes in a construction project and gets squeezed when working to a deadline: this tends to result in rushing or corners being cut to get the job done. It is virtually impossible to prove that material was defective if the way it has been used would have inevitably caused it to fail anyway. Tile adhesives are a frequent example of this.
The Floors We Deserve
I am not suggesting that all floors should be designed to cope with the worst possible conditions. Floors are, however, one of the keys to proper functioning of a building and cause disproportionate amount of disruption whenever work is needed on them. It therefore makes sense to design them to the better end of a specification and allow sufficient time in the construction programme for correct installation.
The floors we deserve should be well designed and constructed with an understanding of the maintenance requirements as part of the design brief. Life cycle costings may show that the costs of ownership are less if a floor is built to higher initial specification, or highlight that significant maintenance is regularly needed. After hand-over, maintenance of floors should not be a side issue but a mainstream activity which is carried out by professionals, in a professional manner to recognised and justifiable standards.
... we hope this helps!
Carpets for Contract
Dubai; United Arab Emirates
The weaving process
A brief history. It is believed that the Babylonians wove fabrics on primitive hand looms as early as 3000 BCE. The oldest three-dimensional method of making carpets, one that is still used today, is knotting. It is no longer possible to reconstruct exactly when people first began making carpets in the orient. In the 8th century CE, the Moors brought the first oriental carpets to Europe with their expansion into Spain. Knotted oriental carpets were introduced to Germany around the time of the Crusades. As oriental carpets became ever more popular in Europe, King Henry IV of France authorized the first carpet factory in the 17th century.
The first factory-made hand-woven carpets were produced in France, Belgium and England in the 18th century. The most famous carpet types of this era are Tournay, Brussels and Wilton carpets, named after the cities where they were developed. Once the English clergyman Dr. Edmund Cartwright invented the mechanical loom in 1786 (but not yet for carpets) and the Frenchman Joseph-Marie Jacquard invented the machine that bears his name in 1805, it was only a matter of time – until 1822, to be exact – until mechanical looms for heavy fabrics were invented, by the Englishman R. Roberts.
The first mechanical carpet loom was presented to the world at the 1851 London Exhibition by E. Bigelow of Boston. In Germany, a carpet industry developed around the middle of the 19th century in response to the rising demand. (ABB.) Power pile wire loom.
Pile wire weaving process
In weaving, two thread systems are crossed at right angles. The lengthwise threads are called the “warp”, and the crosswise threads are called the “weft”. When weaving pile carpets, the pile height is recognized as an additional third dimension.
Thus, three warps are required:
As the threads that make up the pile can only be raised a lowered as one by the shaft, the pile wire weaving process can only produce single-colour material or material that is striped along the direction of the warp. After passing through the heald grommets, the threads of the three warps are passed through a weaving reed (harness). The weaving reed consists of flat steel bars, and the distance between these determines the “warp line” of the material. One pile warp thread, two binding warp threads and one ground warp thread run through each gap between two reed bars.
The weaving cycle
In weaving, the shafts are raised and lowered to form the pile and binding sheds. A steel pile wire is automatically inserted in the pile shed. The height and thickness of this pile wire determines both the height of the pile and the size of the nap. The reed pushes the pile wire lying on the base and binding threads forward. The pile threads are lowered onto the steel wire, enmeshing it in the weave. Additionally, the shuttle transports the weft threads into the binder shed. Once a set of pile wires (around 20) is firmly woven in the fabric, the first pile wire is withdrawn and inserted in the next pile shed via a transfer mechanism. In the manufacture of velour weaves, replaceable blades are mounted on the heads of the pile wires. When the pile wires are withdrawn from the weave, the loops are cut, creating the distinctive velour look and feel.
... Next: The Jacquard weaving process
Carpets For Contract
Dubai, United Arab Emirates
Doubled yarns of various types and qualities are made by combining two or more yarns of equal or differing thicknesses and then twisting those using doubling machines. The twist of the yarns (Z = right-handed, S = left-handed) is usually opposed to the rotational direction of the yarn spindles. Doubling increases the strength and uniformity of the yarn.
In order to maintain certain yarn structures, single and multiple yarns are twisted normally or over-twisted. The over-twisting of the yarns gives rise to a crimp effect, which causes a displacement of the nap of the carpet pile (twist, frisé). To ensure that this effect remains permanent, the yarn must be fixed in this over twisted state. To this end, the yarn is treated with heat and steam in a so-called heat-set process.
Dyeing is the term for the technical process of colouring textiles. Originally, textile makers were limited to natural dyes derived from vegetable, animal or mineral materials. Indigo and madder red (alizarin) are two of the most familiar examples of vegetable dyes.
Purple dye, which was extracted from a type of snail, is an example of an animal dye. The extraction of this dyestuff was highly difficult and extremely expensive – around 12,000 snails had to be processed to make just one gram of the dye! Another natural dye was cochineal red, which was gained from the female of a species of coccid. Examples of mineral dyes include chrome yellow, cinnabar, Vienna green and ultramarine. Around the mid-19th century, the first artificial dyes were manufactured. These are complex, intricately structured hydrocarbon compounds.
Today, it is possible to dye textiles virtually any colour. Consequently, not only is the attractiveness of a dye important, but also its resistance to light, water and mechanical abrasion. Resistance to acids and bases may also be important criteria in some special applications.
The hot dye bath (an aqueous solution or slurry of dyes) is brought into intense contact with the material to be dyed (pumped, saturated). In the process, the dye is absorbed into the material. It is possible to dye fibres, yarns and entire carpets. These require different dyeing processes and machines:
Production-dyed fibres and yarns
These fibres and yarns are dyed right in the spinning process – the dye is added directly to the spinning material (spinneret dyeing). The result is fully dyed filaments, which can also be produced in mottled or thrown patterns.
Dyeing fibres and yarns
The material is dyed using what are known as circulation systems, in which the fibres or yarn to be dyed are placed. The material rests motionless while the dye bath is evenly pumped through it. Fibres are always dyed in a package system (flock dyeing), while yarns can be dyed using both package and suspension systems (hank dyeing). Modern industrial circulation systems can dye up to 2,000 kg of yarn in one colour batch. When dyeing fibres, the amount of material that can be dyed a particular colour at one time is virtually unlimited, as dyed segments with slight differences in colour are mixed before spinning to ensure a uniform colour.
Unlike production-dyed yarns, this process uses multiple dyes for each yarn. The sections of each colour can be long (“long-spaced”), or very short-spaced when a dot effect is desired. Whereas in space dyeing the dye is printed on, space treating uses chemical resist substances; these cause a varied colour uptake in subsequent piece dyeing.
Fibres and yarns must already be dyed before they are made into carpets. It is not possible to respond to customers’ colour preferences on an ad-hoc basis. The solution to this problem lies in piece dyeing. Unlike the circulation process described for dyeing fibres and yarns, in piece dyeing the carpet itself is moved through the dye bath.
In the discontinuous process (vat dyeing), up to 200 running meters of carpeting 400 to 500 cm wide are run through the dye bath as an endless belt. In this process, the carpeting is manufactured from undyed (raw white) yarn and then dyed the desired colour. This piece dyeing process acquired enhanced importance with the development of tufting technology and the introduction of differential-dyed yarns.
Differential dyeing is the process of dying polyamide yarn types that have the same technological properties but different chemical structures in a non-uniform manner. This means that the yarns with the various different dyeing properties must be utilized in the production of the raw white carpeting in accordance with the desired pattern. The result is that up to three different hues can be produced in a single dye bath. Multicolour effects can be achieved using yarns treated with a dye-resist process. Piece dyeing can be performed using either a vat or a continuous dye process, in which a virtually unlimited amount of carpeting can be dyed a specific colour.
Printing (Chromo-Jet process)
As in piece dyeing, the raw-white carpeting is fed into the printing system in its fabrication width.
The material is transported to the printing table via a material buffer, a steamer and brushes. The material is then halted here, and the printing head moves transversely to the direction of travel (tuft direction) from position 1 to position 2. The printing table advances the material 1.6666 mm (1 cm/8 corresponds to a dot spacing of 1.666 mm) and the head returns from position 2 to position 1. Once the printing head has reached position 1, the material is advanced and the printing head starts again.
The printing head has 64 nozzles per colour, arranged in an 8 x 8 matrix. The printing head is equipped with a total of 768 nozzles, which means that up to 12 colours per design are possible. As the actual nozzle body has a diameter off around 2 cm, the 64 nozzles per colour are arranged diagonally. These nozzles are controlled magnetically, and can execute up to 400 open/close cycles per second. With the Chromo-Jet process, it is possible to apply spray printing designs to materials with pile weights from approx. 550 to 2000 g/m2.
To be continued...The Weaving Process.
Carpets for Contract
Dubai, United Arab Emirates
History of Carpet Yarn Materials. Lets talk a bit about the different manufacturing processes, materials, etc. Understanding carpets technically is always better, especially in contracts.
Over the past 50 years, the importance of various raw textiles for the home textiles industry has changed greatly. Up until the middle of the 20th century, the demand for textiles was met primarily using natural fibres. Today, natural products make up only about 12 % of fibres consumption for carpeting, while chemical fibres account for around 88 %. The various raw materials fall into the following categories:
Wool is the oldest and best known fibre for making rugs and carpets. The varieties and qualities are as varied as the names and breeds of their supplier, the sheep. The approximately 450 different breeds produce a wide variety of wool types, which are differentiated by country of origin. Only sturdy and robust wools are suitable for making carpets, and carpeting manufacturers select these very carefully. The high elasticity of wool provides for fast recovery, so that the appearance is uniform at all times. Thanks to its ability to absorb moisture without feeling damp to the touch, it helps to maintain a comfortable humidity in indoor environments.
The common belief that chemical fibres are a modern invention is not entirely accurate. As early as the 17th and 18th centuries, the English natural philosopher Robert Hooke and the French physicist Réamur published their ideas for producing “artificial silk”. However, it was not until the end of the 19th century that the Frenchman Count Chardonnet actually achieved this. At the Paris Exposition in 1884, he presented a fabric made of artificial fibres.
The first chemical copper rayon was spun in Germany in the last decade of the 19th century. Artificial acetate silks came to market shortly after the First World War. The history of synthetic fibre materials began on July 4th 1913. On this day, the German chemist F. Klatte, employed by “Chemische Fabrik Griesheim Elektron” applied for a patent for a method of producing fibres on the basis of the polymerization reaction of vinyl compounds. Initially, this invention had just as little practical application as the invention of the German Nobel laureate H. Staudinger, who created the first synthetic fibre in 1927, out of polyoxymethylene.
On July 3rd, 1931, the American chemical company Du Pont & de Nemours & Co applied for a patent for the production of polyamide fibres. A team of scientists, led by Dr. Wallace H. Carothers, succeeded in synthesizing what we today know as nylon, made out of hexamethyline diamine and adipinic acid in a form suitable for spinning. Du Pont brought this product to market in 1938 under the trade name Nylon 6.6.
In 1938, the German chemist Paul Schlack developed a further method for producing polyamide (patent application dated November 11 1938), using norleucine as his starting material. By heating lactam with hydrochloric acid, Schlack succeeded in obtaining a linear polyamide. The process did not violate the intellectual property rights of Du Pont and resulted in the production of Nylon 6, which was marketed under the trade name Perlon.
The numbers 6 and 6.6 indicate the number of carbon atoms in the respective polyamide components. “Poly” means many, and refers to the combination of small molecules to form bigger ones. To make polyamide yarn, the polymer is melted at approx. 250 °C and pressed into spinning nozzles. The thin, solidified strand pressed out of the nozzle is then stretched to many times its length, which creates a strong, extremely thin filament. Thicker yarn, that is required for making carpeting, consists of bundles of filaments. In texturing, the yarn is changed in a physical or chemical process from a smooth filament yarn to form Bulked Continuous Filaments (BCF), gaining the volume necessary for the manufacture of the carpeting. In addition to filament yarn, there are also spun fibre yarns. In this process, the spun threads are joined to form a cable, which is then stretched, crimped and cut to the desired length.
In the next step, these fibres are spun to make yarn. The main difference between spun fibre and filament yarns is that filament yarn consists of infinite filament bundles and spun-fibre yarn of short twisted and spun fibres (“stapled fibres”). By itself, the chosen fibre material is not always the optimum solution. By blending, it is possible to combine the advantages of one fibre with those of another. One of the most widely known blends is 80% wool with 20 % polyamide. Today, in addition to polyamide, manufacturers can also use the synthetics polyacrylic, polyester and polypropylene.
However, polyamide is by far the most important raw material for carpeting in all Western European countries.
Spinning is humankind’s oldest craft. Sculpture has been found in Asia Minor showing a woman spinning that dates back to the first millennium. Originally, a small band of fibres was drawn out of fibre material, wool and leaf fibres between the thumb and forefinger, and twisted and wound into thread by the turning of a spindle.
The first spinning wheel was built in 1530. The first carding machine for separating fibres was built by John Wyatt in 1736. In 1795, James Heargreaves designed the first spinning machine. In a spinning factory, the randomly ordered spinning fibres are first aligned in parallel and then processed into bands of fibres by means of a series of mechanical processes. The agglomerated fibres are opened in a series of matched opposing rollers and then passed downstream (carding engine).
The fibre bands are then cleaned of any impurities, drawn and at the same time, evened. The refined fibre band is transformed into spun fibre yarn through twisting (spinning machine), i.e. the parallel band of fibres is reinforced. This process gives rise to adhesion between the fibres, making the spun material more stable. By means of this process, the spinning fibres – mostly short and medium-length fibres – are spun into a relatively coarse, voluminous, fibrous yarn with a unique yarn character.
NEXT: Doubling, Fixing, Dyeing...
Talking Carpet Specification on Contracts it happens to be that still End-User as well Architects are not really aware about the differences, as well some thinking that Nylon 6.6 is the next release number of 6. There are quite a few reasons about the misconceptions about these two yarn types. Here are a few facts that helps to understand. Recyclability
In terms of the sustainability trend and the involvement of post consumer and post industrial recycled content Nylon 6 is gaining market shares because of its 100% recyclable capacities.
To bring more light into the field of carpet specifications, here is a small guide that explains a few basics, that are often misunderstood or even not even advised that may lead afterward during use to maintenance problems or low performance.
Many construction systems can perform well as long they meet a certain Standard System and All Factors must be weighted. However, here are two main factors:
How Should Construction Specifications Be Used?
As a means of achieving desired performance and Aesthetic Objectives.
Construction vs. Performance: Which Wins?
Neither. They are Totally Interrelated
How Does Construction Affect Performance?
Construction Largely determines performance Construction consists of many facets: Each play a role
Which Construction Components are Most Important?
They are all Important. Each Component acts as a piece of the puzzle. All pieces of the puzzle must mesh to complete the picture:
How “Tight” should a Specification?
Specific enough to achieve the desired performance requirements, but general enough to allow for the manufacturers to use the most effective technology to meet the needs of the project. Some items can be a little more general
Some items can be very specific
Key is to allow for the best choice from the manufacturer’s technology to achieve the Client’s needs.
“Or Equal” Defined Construction OR Performance.
One of the most misunderstood and confusingly used term in Specifications “Equal” is defined by the specifier.
PERFORMANCE rules, and should be “equal” with any competitive product. Aesthetics should be closely duplicated in an “equal” Construction parameters should be secondary to achieve Performance and Aesthetic specifications. “Or Equal” Stands the Legal Test. Federal Courts have ruled that Proprietary Specifications are not a violation of Antitrust Laws… Specifiers make informed judgments on products which they feel best serves their clients needs. “Or Equals” actually enhance competition and opens up projects to a wider array of choices among similar products.
Apples to Apples Comparison
All components of specifications should be the same if they are truly to be equals
Traps to Avoid
The most common trap on many specifications is the reliance on one single factor of a construction specification by which the entire acceptance of a product is justified.
Budget = Cost, installation, maintenance, life cycle