CHAPTER 5
FIBRE PREPARATION FOR SALE OR PROCESSING

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5.1 Objectives

To provide both the buyer and manufacturer with parcels of fibre they can handle confidently, knowing they are uniform and meet the standards required for processing into quality yarns and textiles

To maximise the net returns of the grower.

This can best be achieved by paying careful attention to: producing as few lines as possible from the clip, while maintaining an appropriate degree of uniformity within each line;

eliminating contamination of the clip by removing stained and pigmented fibres and by keeping out all foreign material.

5.2 General Requirements

All textile animal fibres are natural raw materials and as such possess, to some degree, inherent variability. This variability will be present with all the important fibre characteristics that affect processing potential and may, if not properly separated, limit end use and/or grower income. The important variable fibre properties are:

- fineness (fibre diameter)
- hairiness (medullation)
- fibre length
- fibre strength
- colour
- fault(s)

Within a group of animals with a common genetic history and run in the same environment, the fibre harvested from each animal will have similarities, the bell-shaped distribution graph below indicates that the bulk of the fibre within a clip will be similar and the quantity that differs significantly from this and requires separation, will be small.

Figure 5.1 Within clip distribution

The aim of preparing animal fibres for processing is therefore to present lines that have acceptable uniformity of fineness (fibre diameter), colour, length, hairiness and fault.

The degree to which each of the fibre types must be separated depends on:

- the quantity of fibre to be prepared;
- the variability of the lot to be prepared;
- the requirements of the buyer and textile processor.

To ensure the requirements are consistently met, fibre preparation should concentrate on the identification and separation of important fibre characteristics that may, if not adequately separated, limit the textile processing potential, such as:

- mixed fineness
- mixed length
- mixed hair content
- urine stain
- felting
- clumps of vegetable matter (v.m)
- non-scourable acquired stains
- mixed natural colours (pigmentation)
- faeces (dags or dung)
- mineral content (dust/dirt)
- skin pieces
- contamination

The specific preparation requirements for each fibre type will be discussed separately.

Preparation of some fibres such as wool begins well before shearing with dagging, drafting etc.

However, for many of the animal fibres harvested by shearing the preparation begins at the time the animals are shorn. During this operation it is essential that adequate, trained labour is on hand to:

- keep the shearing area clear of second cuts and other short staple fibre;
- the shearing area must be swept clear in between each animal shorn;
- dags and stains kept separate;
- belly fibre kept separate;
- carry each fleece to an area for further preparation. It is usual that each fleece is thrown or laid on a slotted preparation table.

5.3 Preparation of fibres

5.3.1 Preparing Wool

The level of fleece preparation required to remove processing faults will depend on the type of wool and extent of fault. Lambs, hoggets and mature sheep should always be separated before shearing and shorn as separate mobs and likewise with ewes, wethers and rams. Each clip will tend to fall into one of the categories below, depending on the fineness, length, overall colour and/or fault presence in the clip.

The descriptions suggested are for guidance purposes as the names applied to each line made vary considerably from country to country. However, the principle requirements for separation and/or combining of wools remain.

5.3.1.1 On the Shearing Board

It is essential that as each sheep is shorn the woolhandlers follow these steps:

-  after the shearer has shorn the belly wool off and thrown it aside, the woolhandler must pick this up and place it in the receptacle for
   belly wool.

-  sweep the short and/or discoloured crutch wool away, and if present, remove dags and urine stain from the crutch wool;

-  carry the shorn fleece away and throw it onto the skirting table for skirting;

-  sweep the shearing board clear between each sheep. The bulk of this short wool separated on the board will be combined with the
   short second cut wool which falls through the slotted skirting table and forms the wool type known as locks;

5.3.1.2 Skirting Annually Shorn Fleeces

The following guidelines show what should be removed from each fleece, according to the colour of the clip.

These fleeces should be classed for fineness - ie. fine, medium and strong. Secondary lines of off-type fleeces will cater for those of very different length (ie. shorter and/or longer), colour or with significant faults. Remember the bell shaped distribution and place the bulk of the wool in the medium line and keep separate those fleeces which are very different.

         Fine Line                        Separate fleeces 3 microns finer than medium line.

         Medium Line                  Bulk of clip.

         Strong Line                    Separate fleeces 3 microns stronger than medium line.

In addition, the following wools, if present, must be kept separated from the main fineness lines and placed in secondary lines depending on the overall colour of the clip.

Well bred Crossbred farm clips usually do not need to be subdivided into fineness brackets, but this will depend upon the age of the sheep, the fineness range present and price differentials. It is important that off-type fleeces be removed from the main line.

5.3.1.5 Wools Shorn at 3-9 Month Intervals

This caters for coarser wools which have less than one year's growth, often 5-8 months. The fleeces do not hold together and are best handled on the shearing board, then taken to a stack on the wool room floor for blending and checking before pressing. Shorter and/or discoloured wool, urine stains and dags, should be removed from the main body wool as it comes off the sheep and each type placed in a separate line. Lambs and other short wools can generally be divided into two lines:

- The body wool.

- The shorter and discoloured wools from the belly, legs and crutch and is known as the Bellies and Pieces.

Figure 5.4

In many wool producing countries, particularly in Asia and the Middle East, sheep are owned in relatively small numbers and flocks over 50 sheep are rare. In these circumstances, the sheep are shorn, often in the field and each fleece is rolled up into a bundle, packed in sacks and sold to local merchants. The merchant combines small lots into larger, more marketable parcels of wool.

It is desirable that these merchants sort the wool prior to on-selling to processors. This sorting should follow this sequence.

- Unroll each fleece on a slotted table to allow dirt and dust to fall free.
- Remove the dags.
- Remove unscourable brands.
- Separate the pigmented wool which may be sorted to colour, fineness, length etc.
- Separate felted fleeces or portions of fleeces.
- Separate clumps of vegetable matter.
- Remove contamination.

Once the fleeces have been sorted as above, it may be necessary to grade the remaining fleece wool into broad fineness categories such as:
                  < 25 microns
                  < 30 microns
                  < 40 microns
                  > 40 microns

However, if sorting to fineness is to be carried out, specific customer requirements/specifications may determine the level of sub-division.

The fleeces may also be graded for length, such as:

                  > 100 mm
                  < 100 mm.

The length brackets made may, as with fineness, be determined by customer requirements/specifications. When sorting is completed the lines made must be pack in sound new packs to prevent contamination and clearly identified with sellers worked, bale number and description of contents.

5.3.2.1 Preparing Mohair

Shearing: The shearing board should be kept free of locks and must be swept after each animal is shorn. Bellies should be picked up from the shearing board, and after removing stained fibre (if applicable) placed in a suitable line.

Skirting the fleece: The following procedure should be consistently adopted:

Remove if present

1. All stained pieces - keep separate.
2. Fleece portions with kemp and keep separate.
3. Heavy grass seeds or burr.
4. Any areas significantly different to the bulk, eg. coarse hairy britches or stronger neck hair.

In most cases, mohair produced on clean pastures will require only careful light skirting.

Classing guidelines: Because of the range of Mohair produced, the following should be regarded as a guideline only.

Classing is the grading of mohair according to fineness, length and type. Uniformity of all the mohair within one line has an important bearing upon its value and processing performance. The classer's aim should always be to accumulate large even lines, but pigmented, kempy, stained or short mohair must always be kept separate from the main lines.

The classer should consider making the following distinctions:

Superfine kid              > 90 mm          < 26 micron            < 2% kemp
Fine kid                      > 90 mm         < 30 micron            < 2% kemp
Fine kid                      > 90 mm         < 30 micron            2-4% kemp
Young goat                 > 90 mm         < 34 micron            < 2% kemp
Young goat                 < 90 mm          > 34 micron           < 2% kemp
Young goat                 > 90 mm          < 34 micron           2-4% kemp
Young goat                 < 90 mm          < 34 micron           2-4% kemp
Crossbred                                          < 34 micron           4-7% kemp
Adult                          > 90 mm          > 34 micron            < 2% kemp
Adult                          > 90 mm          > 34 micron            > 2% kemp

Length: Evenness of length is extremely important when marketing mohair, the ideal length being between 90mm and 150mm. In large lots of mohair it may be possible to grade the hair into separate lengths, ie. 150mm, 125mm, 90mm. However, if the quantity of mohair does not allow for 3 lengths, the 90mm to 150mm hair may need to be blended. It is suggested therefore that provided the quantity allows three lengths brackets be made:

A:         125 mm - 150 mm
B:          90 mm - 125 mm
C:         Under 90 mm

Style and Character: Evaluations of sale lots over ten years in South Africa have shown that whilst style and character does not affect price to the same extent that fineness does, it nevertheless is significant. Therefore, fleeces lacking style and character should not be included in the top fleece lines.

Procedure: After the fleece has been skirted and the stained and kempy portions removed, the fleece should be carefully appraised as outlined for fineness, length, style and character.

The fleece may have to be subdivided into two or more lines. Usually the longest and coarsest mohair occurs on the neck and the britch may often be shorter and contain more kemp whilst the shoulders and flank form the average. Well bred goats should have even fibre throughout the fleece.

Classing from the table into containers and then checking the contents into bins is a useful practice that is often adopted.

Packaging: Most angora flocks are relatively small, so that most classed lines will not be sufficient to make individual bale lots. Therefore, mixed or part bales are pressed. Note: Do not press wet mohair - stains must be dried before pressing.

A Specification sheet detailing the clip should be completed and forwarded to the selling agent.

It is interesting to note that in South Africa the classing of mohair is governed by Government Notice which requires that certain parts of the fleece such as "breech hair, wasty backs, urine stained hair, locks, shall be packed separately".

5.3.2.2 Preparing Cashmere

Cashmere fibre quality is defined by:

- colour (higher price for white);
- average fibre diameter (finer is preferred in the range);
- range of fibre diameters (narrow range preferred);
- length of down fibre (longer preferred up to a limit);
- impurities (the lower the better);
- grease content.

White is quoted at about twice the price of brown, with light grey midway between.

Better cashmere fibre is produced from a dense-fleeced animal, which also produces more cashmere weight.

As a rule, the finer the fibre the lower the production, and the stronger the fibre the greater the weight. The coarser the fibre the lower the price, and the finer the fibre the higher the price (but generally only down to fibre diameter of 15.5 microns).

Colour: White cashmere fetches a premium. It can be found on animals with black or brown guard hair and skin pigment but is usually from white animals. Other colours are cream, grey and brown. Unfortunately, it is difficult to determine cashmere colour, especially when it is mixed with guard hair.

Usual colour grades are:

- white: pure white;
- grey: although there is some true light grey, most is basically white, with "grey" resulting from small numbers of dark pigmented fibres;
- brown: all pigmented fibres. (Even silver-grey down mixed with black guard hair turns out brownish once dehaired).

Fleece should be classed for colour as:

- white: white down with white guard hair only;
- white and coloured guard hair: no pigmented down fibres;
- light grey:
   (a) white down with small number of pigmented down fibres;
   (b) intermediate down colours of tan, fawn, blond;
- brown: all pigmented down fibres.

The differentiation between light grey (a) and light grey (b) is made because some processors have been paying more for light grey (b) than brown.

Fleece from feral animals should be sorted into two grades of high and low yield of down weight to total fibre, then into colour groups, and packaged separately.

Fibre length: Minimum average cashmere length of 40 mm is desired. Maximum length is not really determined, but a range of 20-65 mm is suggested, and 50-55 mm is ideal.

Fibre diameter: Cashmere fibre diameter is difficult to assess accurately with the naked eye, and objective testing must be used. Fibre yield is affected by nutrition, season and animal health, but in general the greater stress on the animal does not usually affect fibre diameter.

In China, the raw cashmere is sorted by hand in factories. Sorting is carried out by girls who, with a trained eye, are able to sort the fibre roughly into grades and colours. In the more up to date factories, rows of girls sit at tables fitted with grills through which the dirt, grit and sand falls out. In less well equipped factories, the workers sit on the floor. The sorting is done at great speed and requires a high degree of expertise.

Sorting reduces the guard hair in the underdown and the raw material is sorted into three natural colours - white, grey and brown. The different piles of graded fibre are then "willowed". This process entails putting the fibre through a simple revolving machine which shakes out much of the dust and grit. After sorting the material is scoured before being dehaired.

5.3.2.3 Preparing Camel Hair

Camel hair is obtained by a number of methods: by combing, by shearing and simply by collecting the clumps of hair shed naturally during the moulting season.

The fibre is collected from the herdsmen's cooperatives and transported to local collecting stations. In China it is sold principally through the same channels as cashmere, chiefly the China National Native Produce & Animal By-Products Import & Export Corporation.

The colour varies from reddish to light brown and the camel hair is sorted according to shade and age of the animal. Baby camelhair, which has an average diameter of about 19 microns and a length of 2.5-12.5 cm, is the finest and softest. Baby camel holds greater appeal but it is not currently available in commercial quantities.

5.3.2.4 Preparing Alpaca

Shorn fleeces are classed into ten colour categories: white, grey, fawn, light brown, dark brown, black, roan, brown and white, black and white and spotted (or mixed colours).

Fleeces are separated into those less than 1 year-old cria (baby), tui (1-2 year old) and adult, and sorted into (a) premier fleece (back, side, part of shoulder and rump), (b) neck, (c) oddments (apron, belly, legs) or (d) pieces (head, shankings, tail and other extreme hairy pieces) within each colour and age category. Premier fleeces are graded according to fineness into baby (<22 micron), extra fine (22.0-24.9 micron), medium fine (25.0-29.9 micron) and coarse (>30.0 micron) categories. Extremely coarse guard hair and kempy fleeces are also separated from the main lots. Fleeces from tuis unshorn as cria were long, while late born crias had shorter fleeces when shorn with the older crias. Fleeces were therefore also sorted for length into short (<60 mm), medium (60-120 mm) and long (>120 mm) grades.

5.3.2.5 Preparing Angora

Angora is a delicate fibre and great care must be taken when handling and preparing it for sale. Fleeces or part fleeces with lower quality fibre must be kept separate and not allowed to contaminate good quality lines. The common grades the fibre should be sorted into are:

              Grade 1: clean, free of felting, over 60 mm long.
              Grade 2: clean, free of felting, under 60 mm but over 30 mm long.
              Grade 3: clean, felted, second cut.
              Grade 4: all dirty, discoloured fibre.

5.3.2.6 Preparing Yak Hair

There appears to be no sorting of yak fibre carried out at the time of harvesting the fibre from the yaks. After combing the fibre from the yaks it is packed into large sacks and sent off to warehouses/sorting factories. Here the fibre is hand sorted to separate, or more correctly, reduce the quantity of guard hair present in the underdown, also to separate the natural colours. This is a slow process and the sorters handle only about 10kgs per day.

- white, about 10%
- fawn, 20%
- dark grey (blue), 10%
- dark brown, 60%

As the quantities of sorted yak fibre build up it is pressed in bales and sent off for yarn making either for hand spinnng or machine spinning.

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