Fibre blending (fiber blending in US spelling) is the controlled combining of two or more kinds of fibre, such as polyester and cotton, in a known ratio by weight during spinning, so that every length of yarn carries the same mix. In a short-staple mill it happens at three points: in the bale laydown and blowroom, where tufts of each fibre are dosed by mass; at the draw frame, where card slivers of each fibre are fed together in a set number of ends; or at the ring frame, where two rovings are spun into one yarn. At the draw frame the ratio is set by the number of ends and the weight of each sliver; it is checked by dissolving one fibre out of a sample and weighing what is left (ISO 1833), and a blend that wanders shows up after dyeing as barré, streaks and patchy shade. Mixing is the uncontrolled version: the proportions are random and the result cannot be repeated.
Last verified: 11 October 2026. Every figure is cited to a machine maker, a standard, a regulation, a patent or a peer-reviewed paper; the worked example is arithmetic, checked in the site’s calculators. Sources are listed at the end.
Fiber blending at a glance
| Question | Short answer | Where it is explained |
|---|---|---|
| What is a fibre blend? | Two or more fibres combined in known proportions by weight, so the result can be predicted and repeated | What is a fibre blend? |
| Why blend? | To combine properties, even out variable raw material, control cost, make colour effects and help processing | Why fibres are blended |
| Where is it done? | Bale laydown and blowroom (tuft blending), draw frame (sliver blending), after the comber, or at the ring frame (two rovings) | Where blending happens |
| How is the ratio set at the draw frame? | Share of A = ends of A × sliver weight of A ÷ total creel weight; the end split is set first, and where no split of whole ends lands on the ratio, one component’s sliver weight is changed | Blend ratio |
| How is it checked? | Dissolve one fibre (ISO 1833), weigh the rest, and repeat on several samples to see how much the blend varies | Checking the blend |
| Common blends | Polyester/cotton, polyester/viscose, viscose/cotton, wool/polyester, cotton/elastane | Common blends |
| What goes wrong? | Barré, streaks, uneven dyeing and white spots | Faults |
What is a fibre blend?
Blending is combining fibres of different raw materials, lengths, finenesses or colours to make a yarn, which is how the machine maker Rieter defines it in its 2022 study of tuft and draw frame blending. This page is about the blend in the yarn, made before or during spinning; what blending does to the finished cloth is covered under blended fabrics.
Blending is not the same as mixing. In mixing the proportions of the components are random, so the quality of the product cannot be predicted or reproduced; in blending the proportions are known, so the properties can be predicted and repeated (Hossen and Saha, 2023). Rieter’s spinning manual calls what a blowroom mixer makes a random blend; a draw frame creel set to 65% polyester is a blend in the strict sense.
A “chemical fibre blend” is a blend that includes a man-made fibre, such as polyester or viscose, with cotton, wool or another man-made fibre. “Chemical fibre” is the literal translation of the German Chemiefaser: the German man-made fibre association is the Industrievereinigung Chemiefaser. Rieter’s estimate is that 55% of fibre is spun into blended yarn and 45% is processed pure, and it names cotton/polyester as the most popular blend (Rieter, Unique Solutions for Processing Man-Made Fibers, 2021).
Why fibres are blended
- To combine properties. Polyester has the higher tenacity: 46.39 cN/tex against 27.55 cN/tex for the cotton in one blending trial (Hossen and Saha, 2023). Rieter found that more polyester in the blend gave slightly better pilling, from lower hairiness and higher bending rigidity (Rieter, 2022). Cotton brings moisture: the moisture regain the EU uses for fibre labelling, its “agreed allowance”, is 8.5% for cotton against 1.5% for polyester (Regulation (EU) No 1007/2011, Article 2(1)(k) and Annex IX).
- To even out raw material. Cotton varies from bale to bale, so a homogeneous yarn needs fibre from many bales at once: 20 to 48 bales of cotton, or 6 to 12 of man-made fibre, according to the Rieter Manual of Spinning (Vol. 2, §1.2.2.4). This is blending of lots of one fibre, and it is why a single-fibre yarn is blended too.
- To control cost. Metering lets a mill put in only as much of an expensive fibre as the yarn needs, down to extreme blends such as 98/2 (Rieter, 2021).
- For colour effects. Blends of different colours, such as dyed with undyed fibre in a mélange yarn, are made the same way as blends of different fibres (Rieter Manual of Spinning, Vol. 2, §1.4.4.4; Rieter, 2021 and 2022).
- To help processing. In rotor spinning of recycled cotton, polyester serves as a supporting fibre whose longer staple helps carry a high share of short fibre (Rieter, 2021).
The fabric-level reasons are set out on the site’s page on the advantages of blended fabrics.
Where blending happens in the spinning process
Rieter’s spinning manual calls the start of the process one of the most important stages for blending, because the components are still separate there and can be metered exactly (Vol. 2, §1.2.1.4). Its 2022 study adds that the card, every draw frame passage and the spinning machine blend as well, so homogeneity belongs to the whole line rather than to one machine.
| Stage | How the fibres are combined | What it achieves | Its limits |
|---|---|---|---|
| Bale laydown and bale opener | Bales chosen so the laydown averages of length, fineness and strength stay within limits; the opener takes tufts from the whole laydown in turn | Evens out bale-to-bale variation; keeps micronaire steady from one laydown to the next | The opener works off only a few bales at a time, so a mixer must follow; it does not meter two fibres |
| Blowroom mixer | Several chambers filled one after another and emptied together | Long-term evenness of one material | A random blend, not enough for two different fibres or colours |
| Blowroom metering (tuft blending) | Each component dosed by mass before the card | Fibres blended tuft by tuft; the best evenness and blend constancy in ring yarn | A feed line per component; both fibres share one card and its settings |
| Draw frame (sliver or creel blending) | Card sliver of each fibre fed in a set number of ends, typically 6 to 8, then one or two more passages | A ratio set by ends and sliver weight, changed in steps of one end; the usual route for cotton/polyester | The ratio moves in steps of one end; fibre groups stay visible in ring yarn |
| After the comber | Cotton combed on its own; polyester sliver blended with the combed sliver, then two more passages | The cotton gets the combing it needs | Many machines, and a homogeneous blend is harder this late |
| Ring frame (roving blending) | Two rovings, one of each fibre, drafted side by side and twisted together (siro) | The least hairy yarn of the three routes in one trial | More mass variation and imperfections than fibre blending |
| Rotor spinning machine | The opening roller splits the sliver into single fibres, doubled again in the rotor | Blends further, so the route matters less | Rotor yarn only |
Sources: Rieter Manual of Spinning, Vol. 2, §1.2.2.4, §1.4.2 and §1.4.4; Rieter (2022); Rieter’s patent US5155989; Hossen and Saha (2023). Each stage is described below.
Bale laydown and blowroom
The laydown is the first blend. Rieter’s manual puts it at 20 to 48 bales of cotton, or 6 to 12 of man-made fibre, with up to 130 bales from four to six sources in front of an automatic opener; the bales are grouped by their test data, with software, so that the laydown keeps constant averages (Vol. 2, §1.2.2.4 and §1.4.2). Cotton Incorporated lists failure to control micronaire from laydown to laydown, and too high a variation of micronaire within one laydown, among the causes of barré (Technical Bulletin TRI 1002). The bale laydown calculator works the split between two cotton lots for a target micronaire, and the machines are described on the blowroom page.
An automatic bale opener takes from one to three bales at a time in Rieter’s account, and up to 14 on Trützschler’s portal opener BO-P, so a mixer follows it: Trützschler’s MX-U has 6 chambers for up to 1,200 kg/h or 10 for up to 2,000 kg/h. A mixer makes a random blend, right for one fibre but not for two: for cotton with polyester, or for different colours, Rieter’s manual says the blend is made mainly on draw frames, or in the blowroom with a machine that meters each component (Vol. 2, §1.4.4.4). Both makers state a blend ratio deviation under 1% for their metering blenders: Rieter for the UNIblend A 81 (Rieter, 2021), and Trützschler for T-BLEND, which weighs each of up to six components.
Draw frame blending
Each fibre is opened and carded on its own, so each can have its own settings (polyester needs less intensive opening than viscose, for example; Rieter, 2021), and the card slivers meet at a blending draw frame. Rieter’s spinning plan for 30s Ne ring yarn feeds six card slivers of 6,561 tex to a blending draw frame running at 800 m/min, which delivers 5,368 tex with a draft of 7.3 (Rieter, 2022, appendix); Hossen and Saha also used six doublings, and Rieter’s patent describes six- to eightfold doubling. The machine is described on the drawframe page.
The draw frame sets the ratio by ends and sliver weight but blends coarsely. In Rieter’s trial, cross-sections of ring yarn from a draw frame blend still showed groups of polyester fibres where a tuft blend spread them evenly; tuft blending followed by two draw frame passages gave the steadiest blend, and a draw frame blend for ring yarn should have three passages (Rieter, 2022). In a mill trial at Buluko Textile, blowroom-blended 65:35 polyester/cotton yarn had fewer imperfections and less variation in strength and elongation, with almost the same evenness and strength, while draw frame blending was cheaper to run (Mamuye and Gedefaw, 2025, abstract); Rieter’s own cost calculation found the two routes about equal (Rieter, 2022, §9).
Comber, ring frame and rotor
Combed blends. The cotton has to be combed to remove its short fibres, so in the conventional route the polyester joins after the comber: pre-drawn polyester sliver is blended six- to eightfold with the combed cotton sliver, then drawn twice more with sixfold doubling, 288 doublings in all when the blend is doubled eightfold (8 × 6 × 6). Rieter’s patent US5155989, which describes that route, names its drawbacks (many machines, and difficulty getting a homogeneous blend) and proposes blending before the comber instead.
Roving and rotor. In roving (siro) blending the two strands are drafted separately and meet only at the twist, so the fibres are never blended in the drafting zone; Hossen and Saha found it gave the least hairy yarn but more mass variation than fibre blending. A rotor spinning machine opens the sliver into single fibres and doubles them again, so rotor yarn blends better than ring yarn, and Rieter (2022) found two draw frame passages in all for a draw frame blend (the blending passage and one more), or one after a tuft blend, usually enough.
Blend ratio: how it is calculated and set at the draw frame
A blend ratio is a ratio of masses, never of fibre counts or ends. At the draw frame the mass each component brings is its number of ends times the linear density of its sliver, so:
- Share of A (%) = ends of A × ktex of A ÷ (ends of A × ktex of A + ends of B × ktex of B) × 100. In hank, which rises as the sliver gets lighter (hank Ne = 0.5905 ÷ ktex), it is (ends of A ÷ hank of A) ÷ (ends of A ÷ hank of A + ends of B ÷ hank of B) × 100.
- Sliver weight of A for a target share t = t × (ends of B × ktex of B) ÷ ((100 − t) × ends of A).
- Draft of the blending passage = total mass in the creel per metre ÷ ktex delivered.
Ends come in whole numbers, so with equal slivers the ratio can only move in steps of one end: with six ends, each end is one sixth of the creel. Rieter’s study says what to do when the wanted ratio does not fall on a step: make the card slivers at different counts, which adds work in the card room. It adds that with a 30 to 50% share of the blending component the logistics of the blending process are minimal (Rieter, 2022, §4.3).
Worked example: a 65/35 polyester/cotton blend on six ends
The machine figures are Rieter’s spinning plan rounded: card sliver 6.56 ktex (6,561 tex, a 0.090 hank), six ends at the blending draw frame, 5.37 ktex delivered (a 0.110 hank) at 800 m/min. The efficiency of 85% is an assumption, the calculator’s default. The target is 65% polyester by mass.
| Step | Working | Result |
|---|---|---|
| Nearest end split: 4 polyester + 2 cotton, all at 6.56 ktex | 4 × 6.56 ÷ (4 × 6.56 + 2 × 6.56) = 26.24 ÷ 39.36 | 66.67% polyester, 1.67 points over target |
| Polyester sliver that lands on 65% | 65 × (2 × 6.56) ÷ (35 × 4) = 852.8 ÷ 140 | 6.09 ktex (a 0.097 hank) |
| Creel with the lighter polyester sliver | 4 × 6.09 ÷ (24.36 + 13.12) = 24.36 ÷ 37.48 | 64.99% polyester |
| Draft of the blending passage | 37.48 ÷ 5.37 | 6.98 |
| One polyester end missing | 3 × 6.09 ÷ (18.27 + 13.12) = 18.27 ÷ 31.39 | 58.20% polyester, 6.79 points down |
| Output at 800 m/min and 85% efficiency | 800 × 60 × 5.37 ÷ 1000 × 0.85 | 219.1 kg/h per delivery |
Both creels open ready in the site’s draw frame blend calculator: four and two ends of equal sliver (66.67%, with 6.09 ktex shown as the polyester sliver needed) and the corrected creel (64.99%, draft 6.98, and a shift of −6.79 points if a polyester end breaks, which is the 58.20% in the table). Count conversions between ktex and hank are in the count converter, and the draft and production formulas are worked on the spinning formulas page.
What the missing end means. The two passages that follow each double six slivers together, so a short stretch of sliver that left the blending passage 6.8 points low is one sixth of the next creel, about 1 point, and one thirty-sixth, about 0.2 points, after the third passage. A lot run short of an end throughout is not diluted at all, because every can in every later creel carries the same fault.
Dry mass or as weighed? A mill weighs sliver as it is, with its moisture, but an EU label states a composition from the dry mass of each fibre plus its agreed allowance, the moisture regain set for that fibre: 8.5% for cotton and 1.5% for polyester (Regulation (EU) No 1007/2011, Articles 2(1)(k) and 19(3), Annex IX). Cotton carries far more water, so the basis matters: 65/35 by dry mass is 65 × 1.015 ÷ (65 × 1.015 + 35 × 1.085) = 63.5% polyester once each fibre carries its allowance, and a label reading 65/35 means about 66.5/33.5 by dry mass. Agree which basis the order means before the creel is set.
| Fibre | EU agreed allowance (moisture regain used for labelling) |
|---|---|
| Polyester | 1.50% |
| Elastane | 1.50% |
| Polyamide (nylon), staple | 6.25% |
| Cotton, normal | 8.50% |
| Viscose, modal, lyocell | 13.00% |
| Wool, carded / combed | 17.00% / 18.25% |
Checking the blend: composition and blend variation
The creel arithmetic predicts the blend; analysis of the yarn measures it. Rieter (2022) measured blend constancy by dissolving the cotton out of a series of yarn samples, weighing the polyester that remained, and taking the standard deviation of the proportions. That is the principle of the ISO 1833 series and of the EU’s official methods: a reagent dissolves one fibre out of a known dry mass, and the residue is washed, dried and weighed (Regulation (EU) No 1007/2011, Annex VIII, methods 2, 3 and 7). ISO 1833-1 sets the common procedure and each later part covers particular fibre mixtures. All the fibres must be identified first; ISO/TR 11827 gives the procedures.
| Blend | Fibre measured, and the reagent | Standard |
|---|---|---|
| Polyester/cotton, polyester/viscose | The cellulose fibre (cotton, viscose, modal, lyocell, flax), in sulfuric acid | ISO 1833-11 |
| Wool/polyester and other protein blends | The protein fibre (wool, other animal hair, silk), in hypochlorite | ISO 1833-4 |
| Viscose/cotton | The viscose, cupro, modal or lyocell, in formic acid and zinc chloride | ISO 1833-6 |
| Cotton/elastane, polyester/elastane | The elastane, in dimethylacetamide (not when acrylic is present) | ISO 1833-20 |
| Three fibres | Ternary mixtures | ISO 1833-2 |
| Any | General principles of testing; identification of the fibres first | ISO 1833-1; ISO/TR 11827 |
Scopes as published by ISO for ISO 1833-11:2017, ISO 1833-4:2023, ISO 1833-6:2018, ISO 1833-20:2018, ISO 1833-1:2020 and ISO/TR 11827:2012. Mass variation of the yarn as a whole is a separate test: Hossen and Saha measured it with a capacitance evenness tester under ASTM D1425.
Two kinds of blend error. The average can be off target, which the label tolerance catches, or the blend can wander along the yarn while the average is right, which only repeated samples or yarn cross-sections show. In Rieter’s trial only tuft blending followed by two draw frame passages held the standard deviation of the blend percentage to 0.15 to 0.2; a high polyester share (67/33) was harder to hold steady than a low one (33/67); and pale pastel shades need a more even blend than very dark ones (Rieter, 2022, §6.2).
Label tolerance. In the United States a blend is not misbranded if each fibre’s share by weight is within 3 percent of the total fibre weight of the figure on the label, so a label saying 40% allows 37 to 43%; a product claimed to be wholly one fibre gets no tolerance (16 CFR 303.43). The EU allows a 3% manufacturing tolerance in relation to the total fibre weight (Regulation (EU) No 1007/2011, Article 20(3)). By the creel arithmetic of the worked example, a lot spun with a polyester end missing throughout would be 58.2/41.8 against a 65/35 label, 6.8 points out and outside the band of 62 to 68%: open that case in the fibre content tolerance calculator. The site’s older page on blended fibre analysis covers blended and mixed fibre yarns.
Common blends and how they are spun
| Blend | What the sources cited here say | Content test |
|---|---|---|
| Polyester/cotton | The most popular blend (Rieter, 2021). Ratios in the trials: 65:35 polyester:cotton (Mamuye and Gedefaw, 2025); cotton:polyester 50:50, 60:40 and 70:30 (Hossen and Saha, 2023); 2 to 67% polyester (Rieter, 2022). For ring yarn Rieter recommends a draw frame blend for 50 to 70% polyester and a tuft blend anywhere from 5 to 95%; its J 26 air-jet spinner takes cotton with up to 50% polyester | ISO 1833-11 |
| Polyester/viscose | Rieter’s J 26 air-jet spinner takes viscose with up to 80% polyester; viscose needs more intensive opening than polyester (Rieter, 2021) | ISO 1833-11 |
| Viscose/cotton | Air-jet spinning is the dominant route for viscose and its blends with cotton (Rieter, 2021) | ISO 1833-6 |
| Wool/polyester | Outside short-staple spinning: Rieter’s manual names cotton, man-made and regenerated fibres as its raw materials (Vol. 2, §1.2.2.1). In analysis the wool is dissolved and the polyester weighed | ISO 1833-4 |
| Cotton/elastane | The elastane goes in as a continuous filament, as the core of a cotton-covered core-spun yarn (Helali and co-authors, 2023), so its share is set by the elastane count and draft, not by a laydown | ISO 1833-20 |
For cotton/elastane the percentage is worked from the elastane count, its draft and the yarn count; the method is on the core-spun page under elastane percentage. Cotton itself is described on the site’s page on cotton fibre.
Matching fibre properties
- Length. A drafting system is set to the fibre length (Rieter, 2021), and in a blend it can suit only one component. In Hossen and Saha’s trial the polyester was 34 mm long against 28 mm for the cotton, the settings suited the polyester, and the shorter cotton fibres moved uncontrolled in drafting, raising mass variation in the sliver- and roving-blended yarns. Polyester for the cotton system is bought cut to a staple length: the mills in Rieter’s brochure ran 38 mm at 1.3 to 1.4 dtex, and 44 or 51 mm at 1.3 dtex, and its 2022 trial paired 1.7 dtex, 38 mm polyester with 1 1/8 inch (28.6 mm) cotton.
- Fineness. Cotton Incorporated’s first cause of barré is failure to control fibre diameter, micronaire for cotton and denier for man-made fibre, from one laydown to the next (TRI 1002). Rieter (2022) traces barré in polyester/cotton fabric to variation in cotton fineness and maturity and prescribes bale management to prevent it.
- Shrinkage. A difference in shrinkage between the components changes the yarn when it is heated. The effect is strong enough to be used on purpose: high-bulk acrylic yarn blends about 40% of heat-shrinkable fibre with stable fibre and then shrinks it with heat to bulk the yarn (Mitsubishi Rayon patent US4897990). In a blend meant to stay flat, the components need matched shrinkage.
- Dye behaviour. Polyester and cotton take different dyes. Polyester is dyed with disperse dyes at pH 5 to 7 and 120 to 140 °C; cotton with reactive dyes under alkaline conditions, conventionally in a second bath (DyStar patent US5693103). Each fibre carries its own colour, so a yarn whose share of one fibre wanders dyes to a different overall shade.
Faults a poor blend causes
| Fault | What it looks like | Blending causes | Prevention |
|---|---|---|---|
| Barré | An unintended, repeating pattern of bars or stripes, usually parallel to the weft (filling) of a woven fabric or along the courses of a circular knit | Micronaire or denier not controlled laydown to laydown; too high a micronaire variation in the laydown; poor blending from opening through finisher drawing; yarns of different blend levels mixed in one fabric | Bale management; metered blending; yarns of different lots and blend levels kept apart |
| Warp streaks | Narrow lengthwise bands in woven fabric whose colour differs from the ends beside them | Warp ends spun from a different lot or blend level | The same yarn, of one lot and blend level, in every end |
| Uneven dyed appearance | A less even fabric surface after dyeing, most demanding in pale pastel shades | Fibre groups left in the yarn by a coarse blend; a blend that wanders along the yarn | Tuft blending, or three draw frame passages for ring yarn |
| White spots | Neps or thick places that show as specks in a mélange fabric in which only one fibre is dyed | Polyester not opened well enough, and polyester fibres curling through the process stages | Thorough opening of the polyester and gentle processing |
Barré and warp streaks are as defined in Cotton Incorporated’s TRI 1002, which cites ASTM for the definition of barré and lists the barré causes in the third column; the bulletin gives no causes for warp streaks, so that cell applies its barré cause “mixing yarns with different blend levels” to the warp. The dyeing faults and white spots are from Rieter (2022), §6 to §8. Cotton Incorporated’s bulletin also lists causes that have nothing to do with the blend, such as card-to-card differences, twist, wax and knitting tension, so a barré investigation starts by finding out whether the bars are physical or dye-related.
Questions
What is fibre blending?
Fibre blending (fiber blending) is combining two or more fibres, or several lots of one fibre, in known proportions by weight so that the yarn is the same throughout. In spinning it is done in the blowroom, at the draw frame or at the ring frame.
What is the difference between mixing and blending in textiles?
In mixing the proportions are random, so the result cannot be predicted or repeated; in blending the proportions are known, so it can (Hossen and Saha, 2023). A mixer in the blowroom evens out bales of one fibre; a blend combines different fibres or colours at a set ratio.
What are the advantages of fibre blends?
A blend combines properties, such as the strength of polyester with the moisture of cotton; it evens out variable raw material; it lets a mill use only as much of an expensive fibre as the yarn needs; and it makes colour effects such as mélange possible. The fabric-level advantages are covered on the blended fabrics page.
What is an example of a fibre blend?
Polyester/cotton is the commonest, for example 65% polyester and 35% cotton. Others are polyester/viscose, viscose/cotton, wool/polyester and cotton/elastane, where the elastane is a filament core rather than staple in the blend.
What is a chemical fibre blend?
A blend that includes a man-made (“chemical”) fibre, such as polyester, viscose or acrylic, with a natural fibre or another man-made fibre. Polyester/cotton and polyester/viscose are the usual examples, and their content is tested by dissolving the cellulose fibre under ISO 1833-11.
How do you calculate the blend ratio at the draw frame?
Multiply each component’s ends by its sliver weight in ktex, then divide one component’s total by the creel total. Four polyester ends of 6.09 ktex and two cotton ends of 6.56 ktex give 24.36 ÷ 37.48 = 65.0% polyester.
Sources
- W. Klein, The Rieter Manual of Spinning, Volume 2: Blowroom and Carding (Rieter Machine Works, 2016), ISBN 978-3-9523173-2-7, §1.2.1.4, §1.2.2.4, §1.4.2 and §1.4.4; publisher’s page: The Rieter Manual of Spinning.
- H. Schwippl, The Influence of Tuft and Draw Frame Blending on the Intermediate and End Product (Rieter, June 2022), cited as Rieter (2022).
- Rieter, Unique Solutions for Processing Man-Made Fibers, brochure 3440 (December 2021), cited as Rieter (2021); Rieter patent US5155989 (1992), blended yarn from cotton and man-made fibres.
- Trützschler product pages: bale openers, mixers, T-BLEND tuft blending.
- J. Hossen and S. K. Saha, “Influence of blending method and blending ratio on ring-spun yarn quality: a MANOVA approach”, Tekstilec 66(3) (2023), 227–239.
- W. Mamuye and M. Gedefaw, “Study on impact of polyester–cotton blending methodologies on yarn quality and cost in the case of Buluko Textile Share Company”, Journal of Engineering (2025), article 2411148 (abstract).
- H. Helali, A. Babay, B. Jaouachi and M. Chikhrouhou, “Developing a rheological model for predicting stress relaxation behavior of cotton-covered elastane core-spun yarns”, Indian Journal of Fibre and Textile Research 48(4) (2023), 409–418 (abstract).
- Cotton Incorporated, Technical Bulletin TRI 1002, Barré (1992).
- Patents: US5693103 (DyStar, 1997), dyeing polyester/cotton blends; US4897990 (1990), heat-shrinkable acrylic for high-bulk yarns.
- Standards, by ISO’s published scope and the site’s register: ISO 1833-1, ISO 1833-2, ISO 1833-4, ISO 1833-6, ISO 1833-11, ISO 1833-20, ISO/TR 11827, ASTM D1425.
- Regulation: Regulation (EU) No 1007/2011 on textile fibre names and labelling, Articles 19 and 20 and Annex IX; 16 CFR 303.43, fiber content tolerances (United States).
How this page is kept
Last verified 11 October 2026. Process descriptions and machine figures come from the machine makers Rieter and Trützschler and from Rieter’s spinning manual; trial results from the peer-reviewed papers cited; test methods from ISO’s published scopes; tolerances and moisture allowances from the EU regulation and the US Code of Federal Regulations. The worked example is arithmetic on Rieter’s spinning plan, with an assumed 85% efficiency, and each calculator link opens with the figures quoted here, checked on this date.
Change log. 11 October 2026: rewritten in full as a page on blending in spinning. The earlier version described no blending machine by name, no ratio arithmetic and no test method. It carried unnamed company case studies, including one that called a 65% cotton, 35% polyester blend the best performer, and unsourced claims about nanocoatings, enzyme treatments and digital controls that adjust fibre ratios. It also put carding before the blending of the components and named spinning mules among blending equipment; in a modern short-staple line different fibres are blended by metering in the blowroom or at the draw frame. Images taken from other websites, one of them watermarked, have been removed.
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