Fineness (textiles)

Sewing thread of size Nm 100/3

The fineness of textile fibers (staple fibers, filaments ) and other linear textile structures such as yarns , twisted threads , tops , rovings , rovings and ribbons as well as ropes represent a measure of their thickness, diameter or strength. The smaller the diameter of such a structure, the finer it is or the greater its delicacy. However, since the diameter of most of these structures is difficult to determine due to their compressibility and their irregular or profiled cross-sections, relationships between the more easily determinable mass (weight) and length were established for the definitions of textile fineness. The fineness is given either as length-related mass (weight numbering) or mass-related length (length numbering).

Determination of fineness by measuring the thickness

For fibers, the thickness is an essential characteristic of the fiber geometry, which directly influences the processability of the fibers and the properties of linear and flat textile structures ( nonwovens ) made from them. If the fiber cross-section is circular, such as wool or glass fibers , the thickness is defined by the diameter. With flattened fiber cross-sections, the width or side length can be determined. From the change from the 18th to the 19th century, a large number of methods for measuring wool fineness were developed. The reason was the necessary objective evaluation of the fiber fineness in industrial processing. Different finenesses along the fibers and between them have an influence on the spinning properties and the spinning limits . Price formation, which depends on the fiber fineness, certainly played a further role. Examples of such test methods can be given:

• Measurement with microscope and micrometer (by Daubenton 1779, Ploucquet 1785, Pilgram 1826)
• Measurement with a microscope and other aids (by Dollond 1811)
• Measurement with probes and micrometer screws (by Voigtländer 1815, Köhler 1825, Grawert 1831)

The most reliable instrument from the beginning to the middle of the 19th century was the "wool knife" (eriometer) constructed by Dollond and first described in 1811. He had a device on his compound microscope to see how often ten thousandths of an English inch made up the diameter of a woolen hair. The "degree Dollond" measure named after him therefore corresponded to 2.54 µm. The diameter of the thread of a spider's web was determined to be 1 degree Dollond, the thread of caterpillars with 2-3 degrees, the downy hair of a local goat with 4-6 degrees and that of the "very finest woolen hair" with 4-5 degrees. Like Dollond's method, other wool knives were complicated and time consuming and expensive because of the need to measure individual fibers.

The measurement of the fiber diameter is mostly done with lanameters , which are mostly projection microscopes , the basic principle of which was described by Doehner in 1929. The test conditions are listed in DIN 53 811 (fiber diameter measurement in microprojection of the longitudinal view, July 1970). The diameter of approx. 1000 wool fiber sections is measured on 0.4 to 0.8 mm long pieces of fiber and the mean fiber diameter is determined.

• A further development in terms of the time required for the measurements is a method (measuring device OFDA 100) developed by the AWTA (Australian Wool Testing Authority) for microscopic image evaluation. 2000 measured values ​​can be determined in 20 seconds. The successor to the OFDA 100 is the OFDA 2000 and measures up to 24,000 fibers per minute
• Another method is the FDA (Fiber Distribution Analyzer) device from the CSIRO (Australian Commonwealth Scientific and Industrial Research Organization). Fiber sections cut short with a special microtome flow individually in a non-swelling liquid in a capillary measuring chamber past an optical-electronic measuring device. The fiber diameter is evaluated and further statistical evaluations are carried out. Up to 50 fibers can be measured per second.
• With a special module, the AFIS automatic system developed for fiber length measurement can also be used to determine the fiber diameter, using an air stream for fiber separation. The device is used for cotton fibers, whereby a fictitious diameter is displayed due to the non-round cross-sectional shape.

The diameter measurements with a wide variety of methods are mainly used to classify the wool fiber qualities (wool fineness classes), with average values ​​being determined and, especially in English-speaking countries, being given in microns ( Micron , abbreviation µ). In the International System of Units (SI), this unit of length corresponds directly to the micrometer (µm) and must be replaced. These wool counts are not standardized across the countries. Also to be considered From a breeding point of view and the wool trade, different classifications are also common. There are also extensive summaries and overviews. The wool processed for tops is usually only roughly divided into three wool counts: Merino wool (16.5–24 µm), crossbred wool (cross-bred wool, 24–33 µm) and Cheviot wool (coarser than 33 µm).

For fibers made from inorganic materials (glass, metal) and from synthetic polymers, the identification of the fiber fineness is determined via the fiber diameter or the cross-sectional area, especially for use in technical fields of application. With these fiber types, the cross-section is often circular or otherwise regular. This means that further strength calculations and other mechanical calculations can be carried out in the area of ​​reinforcing fibers in plastic composite materials.

Yarn thickness measurements are rarely used to characterize yarn count, since yarns can be deformed too easily and therefore no objective measurement is possible. Nevertheless, such methods have been developed in the past. In the case of a direct measurement of the thread diameter, a thread is wrapped around a specimen slide, a device preventing it from being squeezed wide, and measurements are then carried out at three points with an eyepiece micrometer. In another method, threads are placed next to each other on a rod and wound up to a marked width under a defined tension. The width is divided by the number of turns to get the yarn thickness. An indirect method determines the yarn diameter via the volume. With opto-electronic and capacitive processes, the non-uniformity of the “yarn diameter” feature can be continuously monitored over longer yarn lengths. Eddy current sensors are used within systems for yarn production with continuous monitoring to monitor the unevenness of the thickness of fiber slivers in order to influence the control of drafting systems via control circuits.

Determination of fineness by measuring mass (weight) and length - numbering systems

Mass and weight to determine the fineness

Until the legal introduction of the International System of Units (SI) in the Federal Republic of Germany with the law on units in metrology and the determination of time ( Units and Time Act , abbreviated as EinhZeitG) of July 2, 1969, it was common in the technical system of measurement to use weight as a measure to be used for the quantity and the kg as the associated unit of measure. For this reason, in the literature and in standard works to determine the fineness of linear textile structures, weight was used almost without exception. When the SI unit system was introduced, the system was based exclusively on the physical system of units, which defined the kilogram as the basic unit for mass. This was taken into account when the derived textile parameters were introduced. Since, however, in the course of the new unit legislation, the tenacious tradition of everyday language (specifying the body “weight” in kg) and also in some branches of technology was used, the implementing ordinance to the law on units in metrology of June 26th allowed 1970 that the units of weight as a designation for the mass used in trade when specifying the quantities of goods are the mass units. DIN 60 910: Textile Fiber, General Fineness Designations, December 1985 edition also indicates that the fineness (length-related mass) of fibers and yarns should be specified as the quotient of the weight in a legal unit of mass and length in km. DIN 1305: mass, weight, force, weight, weight, load; Terms, January 1988 edition refers to it. Based on this, weight is used to calculate the fineness in the more recent specialist textile literature for testing textiles. This general usage of language in this special application area of ​​testing and metrology is the reason that, in addition to length numbering, the term weight numbering and not mass numbering is used. The use of both terms should therefore be accepted in the area of ​​determining and practical application of the fineness of linear textile structures.

Historical development of the fineness numbering

Due to the very regional and country-specific development of the textile trade and the textile industry and the associated trade, different systems for labeling the fiber and yarn count have emerged over the course of hundreds of years, as the dimensions for length and weight have very often developed country-specific and regional . Different numbering systems were and are still used for the different types of fiber and yarn.

The starting point for this was the French silk industry and the English wool and cotton spinning mill for labeling the yarns produced. The number results from this

• from the number of weight units, which go to a certain length of the linear textile structure (weight numbering). The lower the number, the finer (thinner) the linear structure.
• from the number of length units that result in a certain weight (length numbering). The lower the number, the coarser (thicker) the linear textile structure.

One of the first weight numbering was introduced in the French silk industry. It was the old French silk titer (French titre - fineness). This meant the number of deniers (1 denier = 1.2739 g), which a silk thread of 9600 old French yards weighs (one French yard = 1.188 m). At the Paris Congress in 1900, the international, legal (statutory) silk titer was established by replacing the old units of measurement and mass with the metric system . The denier titer  (Td) was then derived from the weight in grams per 9000 m.

In the cotton, wool and bast fiber yarn numbering, length numbering was preferred. For the year 1925, 17 common length numbering systems were specified in Germany, including English, French, but also different for Berlin and Saxony in the case of carded thread numbering. The metric length numbering (number metric [Nm] with the unit m / g) was introduced in Germany in 1942, but was never fully established in the silk and man-made fiber industry for filaments compared to the denier denier .

Since an internationally similar numbering and the advantages of weight numbering were recognized in the 1950s, the ISO committee 38: "Textiles" decided in 1956 to recommend the international introduction of the tex system with the unit "tex".

Weight numbering

The weight numbers indicate the ratio of mass (weight) per length.

Tex system

According to ISO 1144 and DIN 60905, Part 1: “Tex-System; Basics “the Tex system has been introduced internationally and nationally. The unit Tex (unit symbol tex , formula symbol Tt ) was regulated by law with the law on units in metrology of July 2, 1969 in Germany for the specification of the fineness of all linear textile structures; it is a legal entity in all EU countries and Switzerland, and can only be used in this area of ​​application.

The Tex is the unit and basic size of the Tex system.

• 1 tex = 1  gram per 1000  meters .

Often prefixes for units of measurement are placed in front of them:

• 1 mtex (Millitex) = 0.001 tex or 1 gram per 1,000,000 meters or 1 tex = 1000 mtex
• 1 dtex (decitex) = 0.1 tex or 1 gram per 10,000 meters or 1 tex = 10 dtex
• 1 ktex (Kilotex) = 1000 tex or 1 gram per 1 meter or 1tex = 0.001 ktex

A yarn made of the same fiber material and with the same spinning parameters with 300 tex is three times as heavy as a yarn (of the same length) with 100 tex. The higher the Tex number, the coarser the yarn or fiber, that is, the lower the fineness of the linear textile structure. In the case of threads that are twisted from yarns of the same count, the number of individual threads is indicated in the Tex system after the thread number with a multiplication symbol. If a shortening (single twisting) or a possible lengthening and also the helical structure of the twisted yarns are neglected, the fineness of the thread results from the product of the yarn count and the thread count n: Tt thread = n x Tt thread. For example means

100 × 4 tex means that four single threads of 100 tex form a thread with a total of 400 tex, i.e. with a running length of 2500 m / kg.

If the yarn counts differ, the twist count is the result of the sum of the individual counts.

Calculation of the titer (dtex) with known length (in m) and mass (in g)

dtex = 10,000 × mass / length

Calculation of the length (in m) with known titer (dtex) and mass (in g)

Length = mass × 10,000 / dtex

Calculation of the mass (in g) with known titer (in dtex) and length (in m)

Mass = dtex x length / 10,000.

Although the Tex system should actually be used for all linear textile structures, it is mainly used for man-made fibers (both staple fibers and filaments ) and yarns made from them, but also for marking the fineness of rovings and slivers. Fibers are often assigned to fineness ranges: ultra coarse> 10 tex; coarse 10 - 0.5 tex, normal 0.5 - 0.15 tex, fine 0.15 - 0.10 tex, extremely fine 0.10 - 0.01 tex and ultra-fine <0.01 tex.

Denier system

This numbering system of the French silk industry (also historical development of the fineness numbering ) goes back to the old French weight unit denier. Until the introduction of the Tex system, the denier system was mainly used for silk yarns and man-made fiber filaments ( artificial silk ). It is still used to mark the fineness of natural silk, especially in Asia and the USA for filament yarns and man-made fibers. In finished textile products, this term is still used for women's tights or textile motorcycle clothing. The denier unit ( den , symbol Td ) is defined as follows:

1 den = 1 gram per 9000 meters;

For a filament yarn, 15 corresponds to = 15 g / 9000 m. In the case of filament yarns, in addition to the total fineness, the fineness of the individual filaments is often specified. ( D. P. F. denier per filament ).

Conversion: 1 tex corresponds to 9 den.

Length numbering

The length numbers indicate the ratio of length to mass.

Nm system

The unit “number metric” (Nm) was prescribed in Germany from 1942 to 1969. Nm indicates how many meters of a linear textile structure have a mass of one gram. Therefore, a thread with Nm 9 is three times thinner than a thread with Nm 3, ie the higher the Nm value, the finer the linear textile structure

Nm 4 means 4 meters weigh 1 gram.

The unit Nm is mostly used for yarn. The description of the yarns in the Nm system is contained in DIN 60 900, Part 4, July 1988 edition. In particular, this system still occurs in the area of ​​wool yarns. In the further processing areas, the simple calculation of the running length of a yarn that is wound on a yarn spool is desired . If the weight of a yarn Nm 50 z. B. 100 g results in a run length of 5000 m. The fineness of threads in the Nm system is indicated by the number of the single threads and the number of threads twisted; ie a thread Nm 48/2 is twisted together from two yarns Nm 48. Correspondingly, a slightly simplified consideration results in a thread with a total count of Nm 24.

Ne system

Natural fiber yarns with the number English Ne are still on the market . This numbering is used in England, the USA, Asian countries (except China) and Northern Europe. A distinction must be made between Ne _B , the English numbering for cotton yarn , and Ne _L , the English numbering for linen yarn and Ne _K and Ne _W for worsted and carded yarn .

1 Ne _B means 1.6934 meters of cotton yarn per 1 gram. The unit is therefore greater than Nm

1 Ne _L means 0.604772 meters of linen yarn per 1 gram. The unit is therefore smaller than Nm

1 Ne _K means 1.128909 meters of worsted yarn per 1 gram (560 yd / lb).

1 Ne _W means 0.516073 meters of carded yarn per 1 gram (256 yd / lb).

These units are based on the fact that both the length of a coiled English strand (see Hank (unit) ) and the comparative weight of the English pound were non-metric. Also for the English numbering Ne , the twist is given after a slash, in the form Ne _B 28/3.

Nf system

The number French Nf is almost meaningless in Germany. Nf is used in France for cotton yarns. The following applies:

1 Nf means 1000 meters of cotton yarn weigh 500 grams.

This results in the conversion of 2 Nm = 1 Nf.

Calculations

From the context

• ${\displaystyle 1\,\mathrm {tex} =9\,\mathrm {den} }$
• ${\displaystyle \mathrm {tex} \cdot \mathrm {Nm} =1000}$
• ${\displaystyle 254\cdot \mathrm {Ne_{B}} \approx 150\cdot \mathrm {Nm} }$
• ${\displaystyle 254\cdot \mathrm {Ne_{L}} \approx 420\cdot \mathrm {Nm} }$

the following table results.

		to
		tex	the	Nm	Ne B	Ne L
v o n	tex	1	${\displaystyle \mathrm {den} ={\frac {1}{9}}\cdot \mathrm {tex} }$	${\displaystyle \mathrm {Nm} ={\frac {1000}{\mathrm {tex} }}}$	${\displaystyle \mathrm {Ne_{B}} ={\frac {590}{\mathrm {tex} }}}$	${\displaystyle \mathrm {Ne_{L}} ={\frac {1654}{\mathrm {tex} }}}$
	the	${\displaystyle \mathrm {tex} =9\cdot \mathrm {den} }$	1	${\displaystyle \mathrm {Nm} ={\frac {9000}{\mathrm {den} }}}$	${\displaystyle \mathrm {Ne_{B}} ={\frac {5315}{\mathrm {den} }}}$	${\displaystyle \mathrm {Ne_{L}} ={\frac {14882}{\mathrm {den} }}}$
	Nm	${\displaystyle \mathrm {tex} ={\frac {1000}{\mathrm {Nm} }}}$	${\displaystyle \mathrm {den} ={\frac {9000}{\mathrm {Nm} }}}$	1	${\displaystyle \mathrm {Ne_{B}} ={\frac {150}{254}}\cdot \mathrm {Nm} }$	${\displaystyle \mathrm {Ne_{L}} ={\frac {420}{254}}\mathrm {Nm} }$
	Ne B	${\displaystyle \mathrm {tex} ={\frac {590}{\mathrm {Ne_{B}} }}}$	${\displaystyle \mathrm {den} ={\frac {5314}{\mathrm {Ne_{B}} }}}$	${\displaystyle \mathrm {Nm} ={\frac {254}{150}}\cdot \mathrm {Ne_{B}} }$	1	${\displaystyle \mathrm {Ne_{L}} ={\frac {14}{5}}\mathrm {Ne_{B}} }$
	Ne L	${\displaystyle \mathrm {tex} ={\frac {1654}{\mathrm {Ne_{L}} }}}$	${\displaystyle \mathrm {den} ={\frac {14882}{\mathrm {Ne_{L}} }}}$	${\displaystyle \mathrm {Nm} ={\frac {254}{420}}\cdot \mathrm {Ne_{L}} }$	${\displaystyle \mathrm {Ne_{B}} ={\frac {5}{14}}\mathrm {Ne_{L}} }$	1

If the density ρ of the fiber material is known, the diameter of the fiber d can be determined from the fineness of the individual fiber (mass m per length L ) :

${\displaystyle d={\sqrt {{\frac {4}{\pi \rho }}\cdot \underbrace {\frac {m}{L}} _{\text{Garnfeinheit}}}}}$

Example: A polyester fiber of 1 denier has a mass m of 1 g and a length L of 9000 m. The density is ρ = 1400 kg / m³. Then the diameter d is 10 µm. This calculation assumes a circular cross-section of the fiber.

Test procedure

Test method for determining the fiber fineness

A direct determination of weight and length, which are required to determine the fiber fineness, is given in DIN EN ISO 1973. In this gravimetric test method (weighing method), fiber bundles that contain a certain number of fibers are cut to a specified cutting length and then weighed. The mean fineness Tt of the fibers (in dtex) is calculated from the weight m of the bundle in mg, the cut length l in mm and the number of fibers.

${\displaystyle {\text{Faserfeinheit Tt (in dtex)}}=10\,000\cdot {\frac {\text{Masse m (in mg)}}{{\text{Schnittlänge l (in mm)}}\,\cdot \,{\text{Faseranzahl Z}}}}}$

For example, for a fiber bundle of 100 fibers with a cut length of 100 mm (ie a total fiber length of 10,000 mm) with a weight m of 1.7 mg, an average fineness of the fibers of 1.7 dtex results. Since an average value is determined for the fibers of the bundle, this method cannot determine the range of the fiber fineness of the individual fibers.

Another method is the vibroscope method (vibration method), which is also standardized in DIN EN ISO 1973. It can be used to determine the fineness of the individual fibers if they can be caused to vibrate sufficiently by an external excitation frequency that is forced on them. Since every fiber has a natural frequency due to its fineness, the fiber fineness Tt can be calculated after this has been determined.

An air flow method has been established to determine the fineness of cotton fibers. The indicator of the fineness of the cotton fibers is based on the Micronaire value . The determination of the Micronaire values ​​is described in DIN 53 941: Testing of Textiles - Determination of the Micronaire Value of Cotton Fibers . The Micronaire values ​​determined are usually not converted into dtex in practical use. The identification of the fineness of the cotton fibers is based on these values. However, it is only possible to determine average values ​​from fiber samples, as is the case with the air-flow method, which was developed for determining the wool fineness and is described in ISO 1136.

Test method for determining the yarn count

To calculate the counts of yarn, as set out in the sections on weight numbering and length numbering, you need strands of yarn or yarn sections of a certain length, from which the weight is determined. The counts are determined according to the yarn length available for the test:

• according to DIN EN ISO 2060: Textiles - Yarns of packaging units - Determination of the fineness (mass per unit length) by the strand method ; Edition April 1995. For this purpose, larger lengths of yarn must be available, which are wound on white loops to form yarn strands of a certain length and whose weight is then determined on yarn scales or
• according to DIN 53 830, part 3: Testing of textiles - Determination of the fineness of yarns and twisted yarns - Simple yarns and twisted yarns, textured yarns - Cut-off method ; Edition May 1981, which is mainly used when only short yarn sections can be removed from woven or knitted fabrics. Various test device manufacturers offer automatic fineness testers for yarns and twines.

Others

In the retail trade, suit fabrics are specially awarded, for example as Super 100 , which are woven from particularly fine and therefore expensive yarns with yarn counts of 100 Nm. Fine tights are made from 20 denier or 22 dtex yarns, thicker tights for the winter from 40 denier or 44 dtex yarns.

See also

• Thread size

literature

• Paul-August Koch, Günther Satlow: Large Textile Lexicon. Specialized lexicon for the entire textile industry. Volume L-Z, Dt. Verlags-Anstalt, Stuttgart 1966, pp. 121–122 (keyword "numbering")
• Ralf-Dieter Reumann (Ed.): Test methods in textile and clothing technology. Springer, 2000, ISBN 3-540-66147-6 , ISBN 978-3-540-66147-4 .
• Anton Schenek: Lexicon Yarns and Twists: Properties and Production of Textile Threads. Deutscher Fachverlag, Frankfurt am Main 2006, ISBN 978-3-87150-810-3 .

Web links

• Thread lexicon

Individual evidence

1. ↑ Ralf-Dieter Reumann (Ed.): Test methods in textile and clothing technology. Springer, 2000, ISBN 3-540-66147-6 , ISBN 978-3-540-66147-4 , p. 157.
2. ^ Paul Heermann, Alois Herzog: Microscopic and mechanical-technical textile investigations . Julius Springer, Berlin 1931, p. 285.
3. ↑ Joseph Löhner : Instructions for sheep breeding and wool knowledge for aspiring sheep farmers and economic officials . JG Calve'sche Buchhandlung, Prague 1835, pp. 118–120.
4. ↑ See: Ralf-Dieter Reumann (Hrsg.): Test methods in textile and clothing technology. Springer, 2000, ISBN 3-540-66147-6 , ISBN 978-3-540-66147-4 , pp. 157-162.
5. ^ Paul Heermann, Alois Herzog: Microscopic and mechanical-technical textile investigations . Julius Springer, Berlin 1931, pp. 287–288.
6. ↑ Herbert Doehner, Horst Reumuth (Ed.): Wollkunde . Second, completely redesigned and expanded edition. Paul Paray, Berlin / Hamburg 1964, section wool fineness classifications, pp. 155–170.
7. ↑ Author collective: Textile fibers . Second improved edition. VEB Fachbuchverlag, Leipzig 1967, pp. 370–371.
8. ^ Sächsische Landesanstalt für Landwirtschaft (Hrsg.): Performance test and breeding value estimation in animal breeding . 2. Completely revised edition. Dresden 2005.
9. ↑ Handspinn-Forum , accessed on September 26, 2012.
10. ↑ Anton Schenek: natural fiber lexicon . Deutscher Fachverlag, Frankfurt am Main 2001, ISBN 3-87150-638-9 , p. 194.
11. ↑ Herbert Sommer, Friedrich Winkler (Ed.): The examination of textiles . Springer-Verlag, Berlin / Heidelberg / Göttingen 1960, p. 353.
12. ↑ Ralf-Dieter Reumann (Ed.): Test methods in textile and clothing technology . Springer, 2000, ISBN 3-540-66147-6 , ISBN 978-3-540-66147-4 , pp. 344-351.
13. ↑ Sensors for displacement, distance and position.Retrieved September 26, 2012.
14. ↑ Federal Law Gazette I, No. 62 of June 30, 1970, Implementing Ordinance to the Law on Units in Metrology Section 7 (4), p. 983.
15. ↑ Ralf-Dieter Reumann (Ed.): Test methods in textile and clothing technology. Springer Verlag, 2000, ISBN 3-540-66147-6 , ISBN 978-3-540-66147-4 , p. 163, p. 251.
16. ↑ Author collective: Textile fibers . Second improved edition. VEB specialist book publisher. Leipzig 1967. p. 486.
17. ^ Paul Heermann, Alois Herzog: Microscopic and mechanical-technical textile investigations . Published by Julius Springer, Berlin 1931, p. 259.
18. ↑ Herbert Sommer, Friedrich Winkler (Ed.): The examination of textiles . Springer publishing house. Berlin / Heidelberg / Göttingen 1960, p. 359.
19. ↑ Directive 80/181 / EEC (PDF)
20. ↑ Unit Ordinance .
21. ↑ Wolfgang Bobeth (Ed.): Textile fibers. Texture and properties . Springer-Verlag, Berlin / Heidelberg / New York 1993, ISBN 3-540-55697-4 , p. 100.
22. ↑ DIN EN ISO 1973: fibers; Determination of the fineness - Gravimetric method and vibration method ; Edition December 1995
23. ↑ Ralf-Dieter Reumann (Ed.): Test methods in textile and clothing technology. Springer Verlag, 2000, ISBN 3-540-66147-6 , ISBN 978-3-540-66147-4 , p. 165.
24. ↑ Ralf-Dieter Reumann (Ed.): Test methods in textile and clothing technology. Springer Verlag, 2000, ISBN 3-540-66147-6 , ISBN 978-3-540-66147-4 , p. 166.
25. ↑ Ralf-Dieter Reumann (Ed.): Test methods in textile and clothing technology. Springer Verlag, 2000, ISBN 3-540-66147-6 , ISBN 978-3-540-66147-4 , pp. 253-258.