- The crimp of wool, or the frequency of waves in a wool staple, has been a vital part of the selection of Merino rams and ewes from the early days. Dr Ian Purvis, manager of Program 1 has been studying crimp as part of the Fine Wool Project and reflects on its changing importance in modern wool science. This article is based on a report that he presented in the CSIRO Fine Wool Newsletter.
- We all know that wool keeps you warm, but what is it exactly about the properties of wool that differentiate it from cotton or any other common natural fiber? To help explain what makes wool so different from almost every other material on the planet, we’ve assembled a list of seven interesting properties of wool that you may not know.
- This study reports the latest research into alpaca and wool fibres. In particular, those properties that have received little attention in research literature have been examined. They include single fibre abrasion and bending fatigue, single fibre tensile properties, as well as resistance to compression behaviour. These properties are important because they affect the softness and pilling propensity of these fibres and the resultant fabrics. Clean wool and alpaca fibres were used in this study. Fibre abrasion/bending fatigue measurements were carried out using a Textechno FIBRESTRESS instrument. The resistance to compression (RtC) tests were carried out according to Australian Standard AS3535-1988. The results indicate that wool and alpaca fibres behave quite differently, even though both fibre types are of animal origin. Wool fibre resistance to compression decreases as fibre diameter increases while the opposite appears to occur for alpaca fibres. For both wool and alpaca the number of abrasion/bending cycles at fibre break increases with an increase in fibre diameter, it takes longer to break the alpaca fibres. Reasons for these differences have been postulated based on differences in fibre surface and structure between alpaca and wool.
- The commercial value of unprocessed wool is determined by its intrinsic quality; an indication of capacity to meet both processor and consumer demands. Wool quality is evaluated through routine assessment of characteristics that include mean fibre diameter, coefficient of variation, staple characteristics, comfort factor, spinning fineness, fibre curvature and clean fleece yield. The association between these characteristics with wool quality stems from their correlation with raw wool processing performance in terms of speed, durability, ultimate use as apparel or carpet wool, and consumer satisfaction with the end-product. An evaluation of these characteristics allows wool quality to be objectively quantified prior to purchase and processing. The primary objective of this review was to define and explore these aforementioned key wool characteristics, focusing on their impact on quality, desirable parameters and methodology behind their quantification. An in-depth review of relevant published literature on these wool characteristics in sheep is presented.
- Information on the relationships between micron, curvature, crimp frequency and character.
- Alpaca is flame resistant, meeting the standards of the US Consumer Product Safety Commission's rigid testing specifications as a Class 1 fiber for use in clothing and furnishings. Alpaca is resistant to external water penetration like wool, but can slowly wick away perspiration because of its unique ability to act like cotton in moisture regain. These factors are what makes alpaca feel lighter than wool, but warmer than cotton in cool, damp conditions. Alpaca is water resistant, making spills easy to clean up before water saturates the fiber allowing stains to develop. It is also adsorbent to oils, meaning that the oils do not penetrate the fibers, but merely cling to the fiber for easy cleaning without harsh chemicals. Alpaca is free of lanolin, and thus can be processed without the need for high temperatures or harsh chemicals in washing. Alpaca is a natural renewable fiber with a wide range of applications.
- Luxurious to the touch, yet warm, cozy and lightweight, garments made from alpaca fiber are quickly catching on as one of the world's best kept secrets in the clothing and fashion industry. Once you've experienced alpaca, you can never go back wool for winter wear. Alpaca fiber has a long and colorful history. The ancient tribes of the Andean highlands of Peru, Argentina, Chile and Bolivia were the first to domesticate the wild vicuna which was, and still is indigenous to the area. By selectively breeding this animal, the alpaca breed was developed, becoming a crucial component for the survival of these tribes by providing meat, fiber, hide, fuel and basis for monetary exchange.
- Long ago, alpaca fiber was reserved for royalty. Today, it is sold several ways. Hand-spinners and fiber artists buy raw fleece. Knitters often purchase alpaca yarn. Fiber cooperatives mills collect alpaca fiber and process it on behalf of the producer.
- Cross-section of wool fibre showing paracortical and orthocortical cells – the arrangement of the cells creates the crimp in wool.
- Everyone who comes on the farm these days is concerned about two items - micron count and crimp. I, myself, have written much about the virtues of skinny fleece and bold crimp, so I began to ponder whether this narrow focus was all that healthy for our industry.
- The bending evaluation of the softness of single fiber is important information for both the basic investigation of fiber bending properties and the textile softness. A single fiber axial compression bending measurement is presented. The resistance to bending behavior of wool and alpaca fibers has been compared by a column buckling method. It shows that alpaca fibers have a much higher resistance to bending namely higher bending stiffness than wool and the softer feeling of alpaca fibers mainly due to the lower surface frictional resistance namely easy to slip between fibers.
- This study sought to define the ranges of quality attributes of domestically-produced huacaya alpaca fiber using internationally accepted methods to objectively measure most of the important fiber characteristics.
- With the increased interest in the measurement of fleece samples from alpacas, a number of questions have been raised concerning the meaning of mean fibre curvature on these samples. Whilst some information has been published, there appear to be some divergent views expressed on the importance of this measurement. This bulletin is intended to impart some factual information which may be useful to growers trying to understand the measurement.
- Fibrous fur or fleece coats have an important role in insulating animals and aiding in the maintenance of homeothermy. Alpacas, raised for fibre production, are selected towards the finest fibre to improve the wearability of their fibre in garment form. The thermal consequences of reducing the fibre diameter on the external insulation are unknown, and may have a negative effect for the alpaca's thermal balance. We hypothesised that for a given fibre density, finer fibres would trap more air and provide lower thermal conductivity when exposed to low wind speed, but would be less robust, and so provide less insulation, when exposed to higher wind speed, than thicker fibres. We measured the thermal conductance of eight pelts of similar fibre density but with varying fibre diameter at 0, 1, 2, 4 and 6 m/s wind speeds. Thermal conductivity was similar between pelts of different fibre diameters (P = 0.58) at low wind speed. Conductance increased more in pelts with finer fibres at the high wind speed than in pelts with thicker fibres (P = 0.02). Thus at the same fibre density, finer fibres result in increased heat loss at high wind speed. Increased heat loss at higher wind speed would result in the animal requiring more energy to maintain heat balance below the lower critical temperature, which will reduce fibre production efficiency.
- On completion of this topic you should be able to: • demonstrate an understanding of fibre diameter and the economic importance of fibre diameter • explain and calculate the difference between the standard deviation of diameter and the coefficient of variation of diameter • define the relationship between mean diameter, diameter variation and “coarse edge” or “prickle” • measure staple strength and describe its economic importance • explain the sources of variation in staple strength within a mob of sheep • describe localised vs generalised fibre weakness as determinants of staple strength • define and quantify the relationship between staple strength and each of minimum diameter, along-staple diameter variation, rate of change in diameter, fibre length variation and intrinsic fibre strength • relate raw wool style including the main component traits to economic importance • explain the influence of fibre diameter and fibre crimp on wool handle • describe fibre curvature and the value of curvature
- Crimp is related to the fibers as they appear in an intact lock. Its measured in waviness per unit of length. The prevailing theory is the greater the crimp, the finer the fleece. Cameron pointed out this isn't always the case, however. Many Peruvian alpacas have recently been examined that have little or no crimp, but very fine fleeces.
- Alpaca fibers have some distinct properties such as softness and warmth, which have not been fully understood in combination with the fiber internal structures. In the present investigation, the internal structures of alpaca fibers have been closely examined under the scanning electron microscope (SEM), especially in the longitudinal direction. The results showed that numerous pigment granules reside loosely inside pockets in brown and dark-brown alpaca fibers. These pigment granules were mainly distributed inside the cortical cells, the medullation regions as well as underneath the cuticles. Their size in the brown alpaca fibers was smaller and more uniformly round than in the dark-brown fibers. These granules in colored alpaca fibers loosen the bundle of cortical cells, providing many crannies in the fibers which may contribute to the superior flexibility, warmth and softness of the fibers. Moreover, there are no heavy metal elements found in the granules. The mordant hydrogen peroxide bleaching employed could eliminate the pigment granules and create many nano-volumes for further dyeing of fibers into more attractive colors.
Intrinsic Curvature in Wool Fibres is Determined by the Relative Length of Orthocortical and Paracortical CellsHair curvature underpins structural diversity and function in mammalian coats, but what causes curl in keratin hair fibres? To obtain structural datato determine one aspect of this question, we used confocal microscopy to provide in situ measurements of the two cell types that make up the cortex of merino wool fibres, which was chosen as a well-characterised model system representative of narrow diameter hairs, such as underhairs. We measured orthocortical and paracortical cross-sectional areas, and cortical cell lengths, within individual fibre snippets of defined uniplanar curvature. This allowed a direct test of two long-standing theories of the mechanism of curvature in hairs. We found evidence contradicting the theory that curvature results from there being more cells on the side of the fibre closest to the outside, or convex edge, of curvature. In all cases, the orthocortical cells close to the outside of curvature were longer than paracortical cells close to the inside of the curvature, which supports the theory that curvature is underpinned by differences in cell type length. However,the latter theory also implies that, for all fibres, curvature should correlate with the proportions of orthocortical and paracortical cells,and we found no evidence for this. In merino wool, it appears that the absolute length of cells of each type and proportion of cells varies from fibre to fibre, and only the difference between the length of the two cell types is important. Implications for curvature in higher diameter hairs,such as guard hairs and those on the human scalp, are discussed.
Investigation of the Dyeing Characteristics of Alpaca Fibers (Huacaya And Suri) in Comparison With WoolLuxury fibers have great importance in the field of high added value fabric production, but the studies related to these fibers are very limited. One of these luxury proteinous fibers is alpaca wool. In this study, dyeing characteristics (dye-uptake speed, color efficiency and nuance of color, fastness properties, etc.) of alpaca fibers (Huacaya and Suri) were investigated by taking sheep wool as a reference. Furthermore, analysis such as scanning electron microscopy, energy dispersive X-ray and Fourier-transform infrared spectroscopy was also carried out. According to the experimental results it was found that both dye-uptake speed and amount was in the range of sheep > Suri alpaca > Huacaya alpaca for milling acid dye. Furthermore, when their fastness properties were compared with sheep wool, it could be said that there was no difference for washing and perspiration fastness, while rubbing and light fastness of alpaca fibers were lower than sheep wool.
- Much has been written about crimp and the relationship with curvature, frequency and microns, as well as curvature and compression. Many of the comments you hear are fact and fiction. We have heard the crinkle theory, the popcorn theory and various statements like “crinkle provides bulk which is created by the air pockets” (processors have concerns re the lack of bulk in Huacaya fibre – products too heavy) and of course that “crimp frequency is a reliable indicator of fineness”. I will demonstrate quite clearly that well-defined crimp is more consistent in its relationships with crimp frequency, curvature and micron.
- The crimped configuration prevents wool fibers from aligning themselves too closely when being spun into yarn. As a result it is possible to have wool textile materials with air spaces. Occupying about two-third of the volume. The warmth of wool fabric is due more to the air spaces in the material then to fiber.
- Crimp and bulk, important wool fiber properties, are thought to be related to differences in the protein composition of the orthocortex and paracortex. Fiber morphological studies have demonstrated that the paracortex has a higher proportion of matrix and cysteine than the orthocortex. While there is some evidence for the differential expression of genes between these cell types in the follicle, this has not been demonstrated satisfactorily in the mature fiber. Using proteolytic digestion of wool fibers, followed by ultrasonic disruption to obtain relatively pure fractions of both cell types, the KAP3 high sulfur protein family was found to be present in higher concentrations in the paracortex. This significant finding provides an explanation for the higher cysteine content reported in the paracortex. This represents an advance in our understanding of protein expression variation in the orthocortex and paracortex, and how this relates to key physical and mechanical properties of wool fibers.
- The cortex of a crimped Merino wool fibre comprises two hemi-cylinders, which differ in both chemical and physical properties. The form of the crimp wave is related to alternations in the positions of the two cortical components within the fibre—the ortho- and the para-cortex1–4. The ortho-cortex tends to lie on the convex aspect of the crimp wave and the para-cortex on the concave aspect.
Relationships Between Skin Follicle Characteristics and Fibre Properties of Suri and Huacaya Alpacas and Peppin Merino SheepWe aimed to quantify the number, type and arrangement of skin follicles in Huacaya and Suri alpaca skin and correlate their follicle characteristics with fibre traits of harvested fibre and compared these relationships with those of Merino sheep. Fibre and skin samples were collected from the mid-side of 12 Huacaya alpacas, 24 Suri alpacas and 10 Merino sheep. The mean fibre diameter (MFD ± s.e.) of the Huacaya and Suri were: 35.5 ± 0.9 and 28.3 ± 1.0 μm, respectively. The follicle groups found for alpacas were very different from the normal trio of primary follicles found in sheep and goats. The follicle group of the alpacas consisted of a single primary follicle surrounded by a variable number of secondary follicles. The mean ± s.e. primary follicle density was 3.1 ± 0.3 and 2.7 ± 0.1 follicles/mm2 for Huacaya and Suri, respectively. The mean ± s.e. secondary follicle density (SFD) was 13.7 ± 1.2 and 17.5 ± 0.6 follicles/mm2 for Huacaya and Suri, respectively. The mean ± s.e. ratio of secondary to primary follicles (S/P ratio) was 5.1 ± 0.5 for the Huacaya and 7.3 ± 0.2 for the Suri alpacas. The sheep had higher S/P ratios and SFD, lower MFD and produced significantly heavier fleeces. The key correlations found between traits in alpacas include a negative correlation between SFD and MFD (r = –0.71, P = 0.001) and a negative correlation between S/P ratio and MFD (r = –0.44, P = 0.003) and a positive correlation between S/P ratio and total follicle density (r = 0.38, P = 0.010). The study revealed that important relationships exist between alpaca skin follicle characteristics and fibre characteristics. It was the number of secondary follicles in a group that imparts density and a corresponding reduced MFD.
- In the article are introduced the fine structural characters of sheep hair, alpaca hair and mohair, and tested and compared their functions of strong stretch, crimp and friction. The result shows that the scale of alpaca hair and mohair is thin and dense. Alpaca hair has interrupted or widely-bodied pith cavity, whose scale is not as clear as the other two. Mohair and alpaca hair own a high initial mold and strength, little crimp and friction factor and worse fulling ability. Although they are hard for spinning, yet their product is of fine elasticity, crease resistance and size stability.
- The alpaca fiber weight-loss was carried using the method of H_2O_2 oxidation pretreating combined with Wolsen acid protease processing. The strength and surface friction property was researched after weight-loss slenderizing, and the relationship between the processing condition of Wolsen acid protease and weight-loss, scale frictional coefficient, and frictional effect were analyzed. At last, the linear fit and regression equation between strength retention and weight-loss of alpaca were educed.
- This study compares the resistance to compression behavior of wool and alpaca fibers. It shows that alpaca fibers have a much lower resistance to compression than wool, and there is little correlation between the resistance to compression and the curvature for alpaca fibers. Yet for wool fibers, the correlation between resistance to compression and curvature is very strong and positive. The differences in fiber curvature and scale profiles of alpaca and wool, together with the test method for resistance to compression, may explain their different resistances to compression.
- Staple strength is an important price factor for many wool types and wool growing regions. However direct staple strength assessments for breeding purposes are very expensive. The indirect assessment for staple strength, Coefficient of Variation for Fibre Diameter (fibre diameter variability along and across the fibre), is proven to be well correlated with staple strength within a flock, but less so for across-flock comparisons. AWI and the Department of Agriculture and Food WA have investigated if Coefficient of Variation across the fibre alone, is a better predictor of staple strength for breeding purposes.
- Measurements are reported of the hygral expansion of yarns extracted from permanently set fabrics made from merino and Lincoln wools. For yarns having similar crimp, the hygral expansion of merino-wool yarn is much greater than that of Lincoln-wool yarn. The values in both cases agree with predictions based on single-fibre behaviour. It seems certain that this difference is caused by the presence of a consistent bilateral structure in merino wool, which is absent from Lincoln wool.
- The effect of micron and density on fleece weight yields is discussed and illustrated with graphs.
- The Suri should grow a very lustrous silky dense fibre, which hangs in individual locks, vertical to the body (similar to that of a mohair goat). These locks come in various types, with the ringlet formation and the wave with twist being the most popular.
- The principal component of hair is a protein molecule called keratin. All protein molecules consist of long chains of small molecular units, the amino acids, of which there are 20 different kinds. Each keratin molecule in hair consists of many hundreds of amino acid units, arranged in an irregular order, although not a random one by analogy, the letters in this sentence are in an irregular order, but the sentence has meaning. The order in keratin determines how the molecules fit together, giving the hair strength and flexibility.
- Two experiments were conducted to examine the variation in fibre diameter profile (FDP) characteristics between staples. The mean values of all the FDP characteristics were not significantly (P > 0.05) different between staples prepared using the same and different staple preparation techniques. The residual correlation coefficient’s between staples prepared using the same staple preparation technique for all FDP characteristics ranged from r = 0.60 to 0.96. The correlation coefficients between staples prepared using different staple preparation techniques ranged from r = 0.37 to 0.97. These results indicate that it may not be sufficient to segment a single staple for estimation of certain FDP characteristics to examine differences between individual animals. One staple is sufficient to estimate the average FDP of a group of animals. FDPs generated using different staple preparation techniques can be accurately compared for most FDP characteristics.
Variation in the Softness and Fibre Curvature of Cashmere, Alpaca, Mohair and Other Rare Animal FibresSoftness of apparel textiles is a major attribute sought by consumers. There is surprisingly little objective information on the softness properties of rare animal fibres, particularly cashmere, alpaca and mohair. Samples of these and other rare animal fibres from different origins of production and processors were objectively measured for fibre diameter, fibre curvature (FC, crimp) and resistance to compression (softness). While there were curvilinear responses of resistance to compression to FC and to mean fibre diameter, FC accounted for much more of the variance in resistance to compression. Fibre type was an important determinant of resistance to compression. The softest fibres were alpaca, mohair and cashgora and all of the fibres measured were softer than most Merino wool. Quivet, llama, camel, guanaco, vicuña, yak wool, bison wool, dehaired cow down and Angora rabbit were also differentiated from alpaca, mohair and cashmere. There were important differences in the softness and FC of cashmere from different origins with cashmere from newer origins of production (Australia, New Zealand and USA) having lower resistance to compression than cashmere from traditional sources of China and Iran. Cashmere from different origins was differentiated on the basis of resistance to compression, FC and fibre diameter. Cashgora was differentiated from cashmere by having a lower FC and lower resistance to compression. There were minority effects of colour and fibre diameter variation on resistance to compression of cashmere. The implications of these findings for the identification and use of softer raw materials are discussed.
Variation of Fibre Characteristics Among Sampling Sites for Huacaya Alpaca Fleeces from the High AndesIn the Huancavelica region of Peru alpacas form the main and often only means of deriving an income for 3300 poor families in 60 communities. Ninety percent of alpacas in the region are Huacaya which are grazed at altitudes 4000–4800 m. Little attention has been paid to alpacas grazed in the High Andes. We aimed to: (i) quantify the variation in alpaca mean fibre diameter (MFD), fibre diameter coefficient of variation (CVD), fibre curvature (FC) and staple length (SL) among 24 sampling sites, (ii) quantify the difference between the mid-side sampling site and other fleece components for each fleece attribute, (iii) identify the sampling site with the highest correlation to the fibre attributes of the fleece in general, and (iv) quantify the relationship between FC and MFD for alpaca. Adult female alpacas (n = 31, mean live weight 71 kg) were sampled and had their fleece weighed in 8 components. Total mean fleece weight was 3.35 kg (range 2.13–6.01). Staples were measured for length (mm) and tested on the OFDA2000 to determine MFD, CVD and FC. The effect of the site was determined using ANOVA analysis. Values for FC were log10 transformed. Correlations between sites and regression analysis between MFD and FC were performed. The mean values for the mid-side site were: MFD 26.3 μm; CVD 20.2%; FC 34.9 °/mm; SL 91 mm, which were finer and longer than other fleece components. The variation in MFD between the 24 sampling sites was 20.2–50.6 μm and between 9 sampling sites in the main fleece saddle was 24.8–31.7 μm. Fleece attributes varied significantly between all fleece components and among fleece sites (P
- Greasy fleece weight (GFW) Clean fleece weight (CFW) Fibre Diameter (FD) Staple Strength (SS) CV of fibre diameter (FDCV) Staple length (SL)
- Wool fiber: Like all other protein fibers, wool is also derived from the animal hair. Wool is mainly used as a minor blend (up to 10%) with cotton to introduce special properties to the terry fabric. Raw wool contains a wide variety of impurities, which can account for between 30% and 70% of the total mass. The impurities consist of wool grease, secreted from the sebaceous glands in the skin; suint, produced from the sweat gland; dirt and sand. Wool grease consists chiefly of esters, formed from a combination of sterols and aliphatic alcohols with fatty acids. Suints consist primarily of the potassium salts of organic acids.
Wool Fibre Crimp is Determined by Mitotic Asymmetry and Position of Final Keratinisation and not Ortho- and Para-cortical Cell SegmentationCrimp, a distinguishing feature of sheep fibres, significantly affects wool value, processing and final fabric attributes. Several explanations for fibre bending have been proposed. Most concentrate on relative differences in the physicochemical properties of the cortical cells, which comprise the bulk of the fibre. However, the associations between cortical properties and fibre crimp are not consistent and may not reflect the underlying causation of fibre curvature (FC). We have formulated a mechanistic model in which fibre shape is dictated primarily by the degree of asymmetry in cell supply from the follicle bulb, and the point at which keratinisation is completed within the follicle. If this hypothesis is correct, one would anticipate that most variations in fibre crimp would be accounted for by quantitative differences in both the degree of mitotic asymmetry in follicle bulbs and the distance from the bulb to the point at which keratinisation is completed. To test this hypothesis, we took skin biopsies from Merino sheep from sites producing wool differing widely in fibre crimp frequency and FC. Mitotic asymmetry in follicle bulbs was measured using a DNA-labelling technique and the site of final keratinisation was defined by picric acid staining of the fibre. The proportion of para- to ortho-cortical cell area was determined in the cross-sections of fibres within biopsy samples. Mitotic asymmetry in the follicle bulb accounted for 0.64 (P < 0.0001) of the total variance in objectively measured FC, while the point of final keratinisation of the fibre accounted for an additional 0.05 (P < 0.05) of the variance. There was no association between ortho- to para-cortical cell ratio and FC. FC was positively associated with a subjective follicle curvature score (P < 0.01). We conclude that fibre crimp is caused predominantly by asymmetric cell division in follicles that are highly curved. Differential pressures exerted by the subsequent asymmetric cell supply and cell hardening in the lower follicle cause fibre bending. The extent of bending is then modulated by the point at which keratinisation is completed; later hardening means the fibre remains pliable for longer, thereby reducing the pressure differential and reducing fibre bending. This means that even highly asymmetric follicles may produce a straight fibre if keratinisation is sufficiently delayed, as is the case in deficiencies of zinc and copper, or when keratinisation is perturbed by transgenesis. The model presented here can account for the many variations in fibre shape found in mammals.
- Alpaca fibre has low crimp and smooth fibre surface. This makes the fibre difficult to process, particularly in sliver/fibre transferring and delivering processes. Blending with wool enhances the alpaca fibre processibility, makes the fibre more easily processed on modern wool processing facilities, and allows the development of new products. To evaluate the effect of wool fibre properties, especially wool crimp, on alpaca/wool blends, two alpaca fibre lots were processed to tops then blended with three commercial wool tops via top gillings. Yarns and knitted fabrics were subsequently engineered with identical machine settings. The performance of alpaca/wool blend slivers, yarns and fabrics has been investigated in this paper.