EP0378616A1

EP0378616A1 - Animal hair solvent treatment process

Info

Publication number: EP0378616A1
Application number: EP19890906665
Authority: EP
Inventors: Peter Stewart Hopkins
Original assignee: WOOLTECH Ltd
Current assignee: WOOLTECH Ltd
Priority date: 1988-06-09
Filing date: 1989-06-08
Publication date: 1990-07-25
Also published as: EP0378616A4; KR960015653B1; AU615559B2; KR900702089A; WO1989012121A1; CN1031074C; NZ229475A; AU3830189A; CN1040229A

Abstract

Le procédé décrit sert à traiter de la laine avec un solvant organique de manière à obtenir un temps de contact optimal pour améliorer la résistance des fibres, la résistance des fibres décroissant après ce temps de contact au fur et à mesure que le temps s'écoule. Le temps de contact a de préférence une limite supérieure de 15 minutes et une limite inférieure de 2 à 3 minutes en fonction du type d'agitation employé dans le procédé de traitement. Le solvant est de préférence choisi parmi des hydrocarbures halogénés ou des éthers halogénés et le procédé de traitement se combine également avec un procédé séparé qui sert à réduire au minimum l'embrouillement des fibres et dans lequel plusieurs masses séparées de fibres de laine animale, qui peuvent se trouver dans leur alignement et dans leur forme d'origine, sont dessuintés séparément les unes des autres dans un milieu de dessuintage pendant un temps de contact minimum avant d'être combinées en un aggrégat avant le cardage.The method described is used to treat wool with an organic solvent so as to obtain an optimal contact time to improve the resistance of the fibers, the resistance of the fibers decreasing after this contact time as time elapses. . The contact time preferably has an upper limit of 15 minutes and a lower limit of 2 to 3 minutes depending on the type of agitation used in the treatment process. The solvent is preferably selected from halogenated hydrocarbons or halogenated ethers and the treatment process also combines with a separate process which serves to minimize tangling of the fibers and in which several separate masses of animal wool fibers, which may be in their alignment and in their original form, are desuinted separately from each other in a desuinting medium for a minimum contact time before being combined into an aggregate before carding.

Description

ANIMAL HAIR SOLVENT TREATMENT PROCESS This invention relates to a process for treating wool and in particular relates to a new solvent treatment process. In general, the most common methods of removing dirt, suint and grease from raw wool have been aqueous processes relying on the use of surface active agents in hot or cold neutral or alkaline water, combined with raking type agitation of the wool. It has been recognized that these traditional methods of aqueous scouring result in fibre entanglement resulting from "slumping" of the wool. This fibre entanglement results in fibre breakage during subsequent carding and combing processing steps. Typically the average fibre length in processed wool tops is 70% to 80% of that of raw or greasy wool. This in turn results in reduced quantity and quality^' of wool reporting as valuable wool top products.

Recent advances in aqueous scouring systems have mainly been directed to reducing the consumption of scour chemicals such as in Soviet Patent No. 1183575.

Other advances, such as that disclosed in U.S. Patent 3708262 to Kanegafuchi Spinning Co. Ltd., Japan, disclose the use of preliminary scouring of the raw fleece in order to reduce the trauma to the fibres. In the above specification scour liquid is drawn down gently through the fleece by suction to remove at least part of the grease and dirt from the wool.

Soviet Patent No. 996532 discloses the use of ultrasonic agitation of the liquid scour medium in an attempt to reduce the physical damage to the wool fibres. This disclosure recommends ultrasonic oscillation of the aqueous medium at between lOOKHz and 250KHz, stating that at lower frequencies complete removal of contaminants is not obtained whilst at frequencies higher than 250KHz, the wool fibres roll up, which has a negative affect on spinning.

Although the above represent significant improvements over traditional hot aqueous scouring processes, all of the above processes realize some loss of fibre length in the wool tops over that of the raw wool. This loss of fibre length is generally believed to be caused by the use of aqueous systems with resultant "slumping" of the wool fibres.

As an alternative to aqueous scouring, and in an attempt to overcome the inherent problems associated with it, there have been proposed several solvent and solvent related processes for scouring wool. For example, both British

Patent No. 1233901 and U.S. Patent No. 3,619,116 propose the use of trichloroethylene or perchlorethylene as the scour liquid, with the usual vigorous agitation. The used solvent is then extracted with water/alcohol and distilled to recover solvent and purified lanolin.

Other advances using solvent scouring technology include that disclosed in Australian Patent Application No. 40379/85 to Extraction de Smet which involves a washing using an aqueous/alcoholic solution. This is then followed by rinsing the wool in a hydrocarbon solvent.

U.S. Patent No. 3,600,124 discloses a process using a hydrophiliσ solvent or mixture of solvents (such as acetone) as a post-scour to a conventional aqueous scour. Similarly, U.S. Patent No. 4,343,619 proposes the use of a solvent post scour to reduce the residual grease content of the wool. Japanese Patent Application No. 138032/76 conversely discloses the use of an initial solvent scour using high flash point petroleum solvent prior to an aqueous scour. The stated object of this process is to reduce the waste water quantity whilst increasing wool grease recovery, and as such it is thought that the resultant scoured wool will have the same properties as conventionally scoured wools.

South African Patent Application No. 5106/73 proposes the use of an emulsion scour comprising an aqueous medium, a non-ionic surfactant and a non volatile solvent selected from animal and vegetable oils. Again, this method has the inherent properties of aqueous scours.

Reference is also made to a wool scouring process described in U.S. Patent 4,343,619 and Australian Patent 533,117. This process included the following steps:«-

(i) treating greasy wool with 'organic solvents including 1,1,1, trichloroethane and methylene chloride; and

(ii) subjecting the wool treated after step (i) to an aqueous washing or scouring procedure as described above. The above process only used the organic solvent as a preliminary scour followed by the normal and conventional aqueous scour. Thus it is considered that the disadvantages as described above with aqueous scours were applicable to this process.

However, it also must be borne in mind that the above process only disclosed use of 1,1,1, trichloroethane as a preliminary cleaning step prior to use of an aqueous cleaning or scouring step. The above process could not be utilized in many applications because of the problems and cost in conversion of existing plant or equipment using an aqueous scouring step to incorporate preliminary treatment by immersion of the greasy wool in the organic solvent. Further, this procedure still involves the use of a final aqueous cleaning or scouring step. Such a step will still result in "slumping" of the wool fibres leading to subsequent entanglement and resultant fibre breakage during combing and/or carding. ^' Also the disclosure of U.S. Patent No. 4,343,619 and Australian Patent 533,117 states that it is essential that in the abovementioned initial step of cleaning the greasy wool with the organic solvent it is also essential that the organic solvent include 0.1 to 10% of a raw animal hair grease which has been extracted from the same type of greasy animal hair undergoing processing. The inclusion of the raw animal hair grease is not required in regard to the present invention and thus the process and apparatus of the present invention is simplified. Also U.S. Patent No. 4,343,619 and Australian

Patent No. 533,117 refer to the production of a scoured animal hair material retaining 1 to 3% by weight of residual soapy substance and 0.3 to 5.0% by weight of residual fatty substance. Again the deliberate inclusion of these substances is not required in the present invention. Also U.S. Patent 4,343,619 and Australian Patent 533,117 refer to the inclusion of an additional step of moving either one or both of the animal hair material and the scouring liquid in relation to each other at a relative speed of 3 to 60 m/min. This additional step is not essential in the present invention particularly in batch processing. However for continuous processing on belt conveyors this counter-current flow of scouring fluid and wool fleece is preferred but the relative flow rates are not critical to scouring performance.

It is an object of this invention to provide a process of scouring wool which alleviates at least some of the problems associated with the prior art and also significantly improves fibre strength. This in turn may lead to an increase in fibre length and value of the subsequent wool top products for yarn and fabric manufacture. The increase in fibre strength may also increase wool top to noil (short fibre) ratios by lower fibre breakages.. It is a further object of the invention to provide apparatus suitable for use in the above process.

The process of the invention includes the steps of treating wool with an organic solvent optionally comprising a halogenated hydrocarbon, halogenated ether or mixtures thereof for an optimum contact time to improve the fibre strength.

In regard to the present invention it has now been discovered that there is an optimum contact time between the organic solvent which preferably is a halogenated hydrocarbon inclusive of trichloroethane and methylene chloride. In other words, there is an upper limit relative to the contact time which is dependant on various factors such as method of agitation, the specific solvent and the specific animal hair being processed. Also animal hair quality may be a factor such as fibre diameter, original fibre strength and fibre type.

It has therefore been discovered that the abovementioned upper limit relative to contact time is suitably of the order of 15 minutes and more suitably 10 minutes for normal agitation methods and in some cases less than 5 minutes for extreme agitation methods (e.g. ultra¬ sonic vibration) . It has been further found in the case of extreme agitation methods (ultra-sonic vibration) that after the aforesaid upper limit has been reached that the fibre strength decreases with the duration of time to eventually reach its original value. As the fibre strength decreases beyond its upper limit the fibre becomes increasingly brittle. This fibre brittleness has been the observed disadvantage of solvent scoured wool in the past. This invention not only increases fibre strength but stops the solvent reaction process at a point where no real damage is done to other fibre properties.

In the case of wool subjected to normal agitation methods (including submersion and jetting of the submersed wool with low pressure high solvent jets) the fibre strength increases progressively during the first 10 minutes. The actual fibre strength values after 10-15 minutes are variable and unpredictable in that they can continue to increase or decrease or can even remain constant. Preferably fresh or unused organic solvent is utilized in this invention which may flow counter-current to the wool in a bath. The contact time between the immersed wool and the organic solvent is preferably 6 to 10 minutes and the residual fatty substance content of the spent solvent from the scouring operation is suitably less than 3% (preferably 1.5% to 2.0%) in order to obtain the desired scouring conditions.

If desired a rinsing step may be employed where fresh organic solvent is applied to the scoured or cleaned wool to remove detergent residues added to the solvent in the bath.

The wool if desired can be initially treated in an initial aqueous or organic solvent based scouring step. However, more preferably the aforementioned minimum contact time with the organic solvent can be used as a scouring step particularly when treating raw wool or greasy wool.

The initial aqueous scouring step may comprise any suitable conventional aqueous scouring step as is known in the art and which have been broadly summarized above. Initial aqueous scouring may also include tip scouring to minimise wool slumping. Initial scouring using an organic solvent is preferred particularly when the organic solvent is capable of enhancing the strength of the fibres. Suitably the initial scouring step is such that it does not cause fibre entanglement and/or breakage.

The preferred solvent in regard to the treatment step of the invention is 1,1,1, trichloroethane (TCE) for its relative cost and ease of recovery. A detergent is used to improve TCE performance in cleaning dirty fibre tops. This detergent may be any that is compatible with organic solvents such as an aliphatic liquid hydrocarbon.

The treatment with the solvent may be undertaken in either a batch or continuous process depending on the scale of operations. It is contemplated that, for some processing, batch processing may be more appropriate in terms of the capital cost of plant. For large industrial scale applications, it is regarded that a continuous process would be chosen. Where a batch process is used, the wool is advantageously contained in baskets that are dipped in a bath containing the solvent.

In fact it is particularly preferred to place the wool as an integral fleece in the dip baskets with the normally outer part of the fleece orientated (tip) downwards.

Where a continuous process is used, the fleece is preferably placed on a conveyor belt such as a perforated plastics or metal mesh belt such that the fleece travels preferably tip down through the solvent bath in a partly submerged and submerged manner. Such a belt may need ribs or cleats to maintain fleece movement relative to the counter-current TCE solvent flow..

If required the wool may be contained in a flexible mesh or perforated container to facilitate access to the wool by the TCE and removal of same from the wool.

The cleaning step using trichloroethane (TCE), methylene chloride, or mixtures thereof also results in superior drying performance of the wool.

In common with other scouring processes, the wool after scouring by the process of the present invention is advantageously dried prior to deburring, carding and combing. It is essential to use a centrifugal or other type of spin drying step to achieve maximum physical solvent removal from the wool. This should be done preferably with the tops of the wool oriented outwardly or upwardly in the direction of solvent flow to achieve a flushing action for final removal of impurities. The wool is then dried to the optimum level required for either deburring if required or to that required for efficient carding and combing.

Suitably the wool may be rinsed in TCE or other organic solvent in the centrifuge or spin dryer to maximize removal of dirt or other impurities and traces of residual detergent.

In regard to one embodiment of the invention the wool after immersion in the aqueous scour normally leaves the final wash and passes through a wringer or other suitable mechanical dewatering step prior to drying. In relation to this invention the hot wool can preferably be taken straight from the dryer and immersed in TCE. The immersion time may be at least 2 minutes and need be no longer than 15 minutes depending on the method of agitation. The wool can be then taken from the TCE bath and placed in a spin dryer. The relatively high specific gravity of the TCE and the relatively open configuration of the wool fibres allows for quick and efficient removal of solvent from the wool. Residual solvent levels of less than 2% on a dry wool weight basis can be achieved. The size of the spin dryer and the g forces are typically 200 to 400 but can be in the range 50 to 1000.

Alternatively wet aqueous scoured wool can be processed. The water carried from the aqueous scour into the TCE medium can be separated using conventional techniques exploiting the different specific gravities of TCE and water. This thereby enables recycling of the TCE to be carried out with consequential minimisation of losses. This procedure is not however recommended.

In order to minimise costs and to meet environmental constraints, it is desirable to recover solvent from all stages of the present process. It is also desirable to minimize solvent recycle rates throughout the process. The solvent is recovered by distillation leaving the wool wax as a residue for further refining into valuable lanolin products. Solvent scouring maximizes recovery of wool wax- typically 95% recovery.

The unexpected advantage conferred by the present process on the scoured wool is the actual initial increase in the measured tensile strength of the wool compared to traditional aqueous scoured wool. This increase in scoured wool fibre strength is regarded as resulting in increased wool top fibre length after further processing (i.e. a more valuable wool top product) .

The mechanism by which this fibre strength increase occurs is associated with internal changes to the fibre subsequent to solvent penetration. These changes await biochemical elucidation though it is probable that appropriate solvent treatment causes a biochemical reaction with the cell membrane complex (CMC) of keratin. This complex is congruent with both cortical and cuticular cells. It provides a matrix which is normally the weakest component of keratin. The complex consists of lipid and lightly crosslinked protein material and although it represents only a small proportion of keratin (6%) it is nevertheless important as it very largely determines the tensile strength of that keratin. Exposure of this CMC to appropriate solvent has, in our hands, led to an increase in tensile strength and this probably reflects changes which induce lipid (e.g. cholesterol triglycerides and free fatty acids) removal from the fibre in the initial period of contact. Eventually under ultra-sonic vibration extreme agitation conditions and occasionally under normal agitation conditions the sphingolipids and phospho lipids may be extracted and this will lead to reduced fibre strengths after the initial strength increase period. In the present invention the proposed solvents have a higher vapour pressure than water and both a lower specific heat and latent heat of vaporization. Therefore it takes less time and substantially less energy to dry the scoured wool. Even when the solvents of the present invention are used on wet wool after an aqueous pre scour, drying times and energies are considerably reduced by the formation of solven /water hydrotropes when using specific detergents active in a TCE solvent. This enables easy physical removal of the water content in the spin drying section of the solvent recovery process relative to water rxtraction alone. This water content of the hydrotrope is then recovered with the wool wax product in the solvent recovery distillation step.

Another advantage of the present invention is an improvement in the average colour of the scoured wool, from off-white for aqueous scoured wools to off white to very white for wools scoured in accordance with the present invention.

EXPERIMENTAL

Greasy wool staples were scoured so that twenty five individual staples forming each group to be tested were tested on AWTA (Australian Wool Testing Authority) certified testing device.

In accordance with Table 1 attached hereto the samples were averaged to provide a mean tensile strength for that treatment group. Table 1 identifies the extent to which trichloroethane (TCE) solvent and various treatment regimes can influence the tensile strength of aqueous scoured wool. The tensile strength units are provided in newtons per kilotex. Paired samples were then tested after various immersion times in TCE and the results are provided as stated in Table 1. In this regard the samples were steeped in an open topped vessel and subsequently dried before having their tensile strength measured as described above.

All wool staples were initially scoured using traditional aqueous scouring technology as described below. These samples were processed as individual staples so that the tensile strength could be measured after scouring (aqueous control Table 1). The Wool School at the Brisbane TAFE College kindly enabled us to use their traditional aqueous scour system utilizing KLEENIT detergent (obtained from Campbell Bros. Ltd.) which is designed for the processing of small test batches.

After aqueous scouring the wool was dried in a forced hot air stream and half the staples conditional to allow regain of moisture. All staples were then immersed in 1,1,1, trichloroethane solvent for various times (Table 1), air dried, conditioned and then tested for tensile strength. Before testing the samples were spun dried in a centrifuge having a g force of approximately 300. The centrifuge utilized was a LIGHTBURN spin dryer serial no. 6504. Hence, there is described in Table 1 traditional aqueous scoured samples (aqueous control) and similar samples which have had an additional treatment by way of immersion in TCE. These samples were all measured for tensile strength and the following points summarize the major findings in relation to the treatment of aqueous scoured wool with solvent to increase tensile strength. 1. TCE treatment increases tensile strength of scoured wool .

2. This effect takes place after a minimum immersion period of 2 minutes.

3. The preferred period of immersion is 2-3 minutes for violent agitation (ultra-sonics) and 6-10 minutes for gentle and normal agitation methods.

4. Immersion in methylene chloride or TCE methylene chloride mixtures also imparted the same result.

5. Immersion of aqueous scoured wool straight from the oven gave a slightly improved tensile strength over that observed using dry, conditioned wool at room temperature.

Alternatively, wet wool taken from the final rinse bowl of an aqueous scour can be squeeze dried and then treated in TCE as above to achieve similar results (Table 2). Increases in tensile strength can therefore be achieved by using a TCE immersion treatment either after this final rinse or after the drying process.

Also attached hereto are FIGS 1A, 2A, 2B, 3 and 4A which illustrate the above described behaviour of wool treated in accordance with the invention. Thus FIG 1A illustrates wool treated with vigorous ultra-sonic agitation, FIGS 2A and 2B illustrate wool treated with normal agitation, FIG 3 illustrates an increase in wool tip quality achieved by the process of the invention, and FIG 4A illustrates a graphical analysis of results of fibre testing.

Reference may also be made to Table 3 which refers to testing of wool samples already illustrated above in FIGS 2A, 2B and 3. _ TABLE 1

The effects of various TCE immersion times on the tensile strength of aqueous scoured dry wool with gentle agitation.

Treatment Strength (N/Ktex)

Greasy 30.6 27.8

Control

Aqueous 41.3 65.3 45.2* 45.2 35.4** 35.4 45.0 32.0

Control

TCE 1 min 46.0 47.2 37.8

TCE 2 min 53.0 56.3 39.9

TCE 3 min 49.6 52.9 55.8 44.6 y-r

UI

TCE 4 min 53.0 54.9

TCE 5 min 50.1 84.0 59.8 61.4 51.7 53.8 54.0 45.0 32.5 ,._'

TCE lOmin 49.1 83.6 61.1 60.3 54.0 55.0 48.6 35.6 35.8

TCE 15min 50.3 53.8 55.4 34.3 37.0

TCE 30min 44.0 35.1 47.4

TCE 60min 45.0 34.9 50.7

* Figures in this column refer to the use of CH₂C1, (methylene chloride) In lieu of TCE Mixtures of

TCE:CH 2CI 2 : 1:1 also provided a similar change in strength.

**Figureε in this column represent the result of εlamples immersed in TCE immediately after remova .1 from

TABLE 2 The effects of various TCE immersion times on the tensile strength of aqueous scoured squeeze dried wool, Treatment Strength (N/Ktex)

Aqueous Control 45.2 65.3 36.2 5 min TCE 20^*C 74.8 45.8 5 min TCE 40'C 59.0 5 min TCE 60^*C 55.4 75.2 46.1 5 min TCE 75^*C 56.0

Temperature measurements refer to temperature of final aqueous wash bowl.

TABLE 3

Wool samples used in TCE solvent scouring fibre strength tests as per Figures 2A, 2B and 3 (AWTA Test Certificate results on lots used)

Sample No. Wool Type

1 - as per Table 1 Sample 7

F i b r e Schlumberger F i b r θ F i b r e Vegetable D i a m e t e r Yield S t r e n g th Length (mm) Matter (%) (mucron) (N/Ktex)

22.9 70.9 21 87 0.3

21.8 70.3 22 87 0.2

22.0 73.2 25 98 0.3

26.0 67.9 35 114 2.1

24.7 71.4 26 94 0.9

85B 21.9 71.4 34 69 1.3

64 23.0 76.8 38 99 0.3

85B 21.9 71.4 34 69 1.3

In the case of scouring the greasy wool with the solvent, it was further found that with ultrasonic vibration at 25kHz that the wool samples having an initial tensile strength of 35 N/Ktex increased to a peak of 56 N/Ktex after 2-3 minutes and then decreased to 40 N/Ktex after 20 minutes.

It is also pointed out that in addition to the chlorinated hydrocarbons preferably used in the present invention that other halogenated hydrocarbons may be used such as brominated or iodated derivatives. Also halogenated ethers may be utilized.

Also in regard to agitation techniques that could be employed in both the aqueous scouring step or the organic solvent scouring step as stated previously directional air/water jets or solvent* jets (from the sides and underneath) may be used for example in a bath arrangement or preferably large volume, low pressure solvent jets from above the submerged wool fibres. These jets may be used to replace the conventional agitation raking mechanism used in aqueous scouring processes thereby simplifying the apparatus or equipment recommended.

In another possible* embodiment the wool scouring process could be carried out in large automatic washing machines using gentle agitation, soak, wash, rinse and spin dry cycles with water or solvents (plus detergents) for the first cycle to remove dirt etc. and then solvent for the soak, wash, rinse and spin dry cycles or any combination thereof.

The special washing machine designed with gentle agitation to minimize fibre entanglement would suitably have automatic valves to direct the solvent scour liquors and residues to a standard scour liquor treatment process for residue removal by filtration or centrifugation and then later to direct the solvent liquors to the solvent distilla¬ tion and lanolin recovery processing steps.

The process of the invention may be applied not only to greasy wool requiring scouring but also used to treat dried or wet aqueous scoured wool as may be considered appropriate. The treatment with halogenated hydrocarbon may occur after aqueous scouring or can preferably be the actual scouring process.

It will also be appreciated from the foregoing that the term "wool" refers to animal hair generally and that the process of the invention can be applied to animal hair fibres inclusive of civet cat hair fibres, weasel hair fibres, raccoon hair fibres, astrakhan hair fibres, fox hair fibres, mink hair fibres, chinchilla hair fibres, sable hair fibres, angora and cashmere goat hair fibres, camel hair fibres and alpaca hair fibres.

Reference may now be made to a preferred embodiment of the present invention wherein:

FIG 1 is a flow sheet of the process of the invention; FIG 2 is a schematic drawing of the process of the invention utilizing a batch procedure;

FIGS 3A, 3B and 3C are schematic drawings of the process of the invetion utilizing a continuous procedure; FIG 4 is a schematic drawing illustrating the process of the invention utilizing an alternative continuous procedure to that shown in FIGS 3A, 3B and 3C; and

FIG 5 illustrates a schematic drawing of a recycling procedure for cleaning of solvent used in the process of the invention.

In the drawings there is shown a flow sheet in FIG 1 which is self explanatory. The wool fleeces which are rolled up separately from each other are unrolled before being placed tip down on a mesh conveyor and subjected to a tip pre treatment procedure before being scoured in an organic solvent. This causes separate fleeces to be broken up into clumps of wool before drying of the scoured wool. Used solvent is then passed to a centrifuge to recover spent solvent which is subsequently filtered to remove dirt and oxidized lanolins. The spent solvent is then distilled and the subsequently obtained recovered solvent is passed to the tip pre treatment medium. Wool wax may be recovered from the distillation procedure for subsequent transportation to the refinery for utilization as lanolin products.

IN FIG 2 there is shown a stak of separate fleeces 10 (i.e. aqueous scoured wool or greasy wool) which are placed tip down in baskets 11 carried by conveyor 12 having head rollers 13, tail rollers 14, and intermediate idler rollers 15 approaching tip pre treatment zone 16 in scouring tank 9, which is defined by downward ramp 17, level portion 18 and upward ramp 19. The tips of the fleece may be subjected to gentle cleansins action as described previously. The remainder of each fleece does not contact the scouring medium 20 which may also be applied to the fleeces by agitation sprays 21 in the tip pre treatment zone 16. After passing through the tip pre treatment zone the fleeces in ^'5 baskets 11 pass through level zone 22 wherein they are removed from the scouring medium before being passed into the scouring zone 23. There is also shown downward ramp 24 which passes baskets 11 into zone 23 wherein the fleeces are fully immersed in scouring medium 20 containing halogenated 0 hydrocarbon which is retained in bath 9. The contact time is as described previously and is preferably 6-10 minutes. There are also provided drains 26 and 27 wherein spent scouring medium may be passed for filtration and further purification. Also shown is manifold 23A for application of 5 detergent to scouring bath 20. After passing through scouring zone 23 the baskets 11 are conveyed up upward ramp 28 which includes manifold 28A for applying fresh solvent as a rinse before fleeces 10 are passed to unloading zone 29 wherein the fleeces 10 are unloaded into centrifuge 30 for 0 drying purposes. The fleeces may then be passed to a secondary conveyor 31 wherein the fleeces 10 are passed separately through a dryer 32 before being passed into a cryogenic bath 33 before being subjected to crushing rolls 34. The fleeces 10 may then be loaded onto table 35 in 5 stacked relationship for subsequent treating operations which include carding for example.

Conveyor 31 is controlled by head roller 31A, tail roller 3IB and intermediate idler rollers 31C as shown. In FIGS 3A, 3B and 3C there is shown a plurality of fleeces 10 (aqueous scoured wool or greasy wool) in stacked relationship loading and layout table 36 adjoining scouring tank 9. The fleeces 10 are loaded onto perforated or mesh conveyor 37 separately and subsequently passed into tip pre treatment zone 38. The fleeces are conveniently separated by ribs 37A (only a small number of ribs are shown for the purposes of clarity, but it will be appreciated that ribs 37A are attached to conveyor 37 along the entire length thereof) . The zone 38 includes skimmer box 39, pump 40 and agitation sprays 41, as well as drains 26 and 27 wherein spent scouring fluid 43 may be passed for purification treatment which includes filtering. The skimmer box 39 and pump 40 are useful in clearing top surface debris from scouring fluid 43. There is also included idler roller 44.

The fleeces 10 may then be passed into scouring zone 45 wherein the fleeces are fully immersed in scouring fluid 43 which comprises halogenated hydrocarbons or halogenated ethers as described previously and wherein the contact time is 6-10 minutes. Scouring zone 45 also includes skimmer box 39 and pump 40. Agitation sprays 41 are also utilized in scouring zone 45 which also includes idler roller 44 as well as manifold 45A for application of detergent.

The fleeces 10 may then be subsequently passed through a rinsing zone 46 which is defined by upward ramp 47 of conveyor 37. In rinsing zone 46 fresh recycled solvent is applied to fleeces 10 to remove residual traces of impurities through manifold 46A. There is also included separator 48 which breaks fleeces 10 into clumps, head pulley or roller 49 and idler roller 44. The clumps may then be passed through chute 50 into centrifuge 51 powered by motor and dearbox assembly 52. In centrifuge 51 the fleeces 10 are collected into an aggregate.

Subsequently wool and remaining solvent is passed from centrifuge 51 up conveyor 53 to cyclone separator 54 wherein the remaining solvent is discarded up chimney 55. The remaining solvent passed up chimney 55 may constitute about 3% of the initial solvent that is utilized. Subsequently cleaned wool may be inspected for quality at inspection point 56 before being passed up pneumatic conveyor 57 into storage bin 58 containing baffle 59 and dust collector 60. The final cleaned and scoured wool may be passed through discharge location 61 for subsequent transportation and storage. There is also provided electric motor 62, suction fan 63 for pneumatic conveyor 57 and air exhaust 64.

In FIG 4 there is illustrated an alternative continuous process which does not use a tip pre treatment procedure. The fleeces 10 from loading table 65 are passed into conveyor 66 above the level of scouring fluid 43 before being passed into scouring zone 45. Subsequently a continuous process as described above in FIGS 3B and 3C is utilized.

The recycling of solvent is shown in FIG 5 wherein the scouring tank 9 is supplied with clean detergent or solvent through line 67. The tank is provided with drains 26 and 27 wherein spent or dirty solvent is passed through line 68 to pressure filter 69 before reaching distillation vessel 70. The pressure filter 69 may be precoated with diatomite, bentonite, acid activated clay, carbon or montmorrilonite. There is also provided pump 71 as well as condenser 72 for passage of clean solvent through line 67. Stabilizers may also be added as shown if required. There is also provided line 73 for passage of wool wax 74 or other materials collected from the distillation vessel for further refining. Cooling water may be passed through condenser 72 through lines 75 and 76.

Claims

1. A process of treating wool with an organic solvent for an optimum contact time to improve the fibre strength whereafter said contact time said fibre strength decreases with further effluxion of time.

2. A process as claimed in claim 1 wherein said optimum contact time has an upper limit of 15 minutes.

3. A process as claimed in claim 1 wherein the optimum contact time has an upper limit of 10 minutes.

4. A process as claimed in claim 1 wherein the optimum contact time has an upper limit of 5 minutes.

5. A process as claimed in claim 1 wherein the contact time has a lower limit of 2-3 minutes where extreme ultra¬ sonic agitation is employed.

6. A process as claimed in claim 1 wherein said treatment with solvent is preceded by an initial aqueous scouring step.

7. A process as claimed in claim 1 wherein the solvent is halogenated hydrocarbons or halogenated ethers.

8. A process as claimed in claim 7 wherein the solvent is 1,1,1 trichloroethane.

9. A process as claimed in claim 8 wherein the wool is subject to drying during said optimum contact time or shortly thereafter.

10. A process as claimed in claim 1 wherein during said optimum contact time said wool is treated with detergent.

11. A process as claimed in claim 10 wherein said wool is rinsed with fresh or unused organic solvent after contact with said organic solvent.

12. A process as claimed in claim 1 wherein spent organic solvent recycled from said contact with said wool has a residual animal hair grease substance content of less than 3%.

13. A process as claimed in claim 13 wherein said residual animal hair grease substance contact is between 1.5% and 2.0%.

14. A process as claimed in claim 1 including the steps of:-

(i) providing a plurality of discrete masses of animal hair fibres optionally in their original alignment and form; and

(ii) scouring the plurality of masses separately from each other in a scouring medium for said optimum contact time to improve the fibre strength.

15. A process as claimed in claim* 14 wherein the plurality of masses of wool are combined in an aggregate prior to carding.