AU7181800A - Shrink proofing method of animal fiber - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): Kurabo Industries Ltd.

ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street, Melbourne, 3000.

INVENTION TITLE: Shrink proofing method of animal fiber The following statement is a full description of this invention, including the best method of performing it known to me/us:- (d

IA

BACKGROUND OF THE INVENTION i. Field of the Invention The present invention relates to a treating method which imparts shrink proofing and pilling resistance to animal fiber.

2. Description of the Prior Art Animal fiber is peculiar natural fiber having specific hand-feeling texture depending on sheep breeds, revealing bio-degradability, having various excellent properties such as hygroscopicity, moisture-releasing property, heat retaining property, flame retardancy and dyeing property, and further, water-repellency. It is special fiber which 15 has appropriate fiber strength and elongation permissible for wear and higher abrasion resistance, also from the standpoint of fiber mechanical properties, and has been esteemed for long time. However, felting property in aqueous washing and pilling property in wear derived from a 20 cuticle tissue structure of animal fiber are undesirable natures as apparel wear. Therefore, studies for improving the surface have been long effected mainly on shrink •proofing, and pilling resistant work has also been conducted along with the studies. However, any of them is 25 an improving method sacrificing water repellency which is an inherent nature of animal fiber. A water repellent membrane of animal fiber is an organization for exerting an influence on hygroscopicity and moisture releasing property and for controlling heat transfer accompanied by adsorption and desorption of water, and exerts an influence on heat retaining property and comfortability. In other words, the conventional shrink proofing product can prevent shrink by aqueous washing, but lacks in heat retaining property and comfortability. As a typical shrink proofing work, there is a shrink proofing method using a chlorine agent, and specifically, what is called chlorine-Hercosett shrink proofing method in which a cuticle tissue of animal fiber is hydrophilizated, the tissue is made soft or removed to impart shrink proofing property, and further, the cuticle tissue is coated with a polyamide epichlorohydrin resin (Hercosett resin, manufactured by Dick Herculess) for enhancing the resistance to aqueous washing. Currently, 15 this method is spread around the world, and recognized provisionally as a complete method as a shrink proofing method of wool.

However, from the stand point of environmental conservation spread currently around the world, a shrink proofing work using a chlorine agent and chlorinecontaining resin has caused a problem of the discharging amount of an Adsorbable Organic Halides (AOX), and a novel •shrink proofing method of animal fiber using no chlorine agent is being studied presently. However, a satisfactory 25 method replacing the chlorine-Hercosett shrink proofing method has not been developed yet.

Japanese Patent Kokai No. 126997/1975 discloses a method in which dyeing property and shrink proofing of wool and pilling resistance of a wool-synthetic fiber blended product are improved without deteriorating hand-feeling and fiber strength of wool according to a procedure in which wool sliver is impregnated with an aqueous solution of acids or acidic salts and drained by squeezing rolls, and is placed in a sealed chamber previously filled with an ozone-containing gas having an ozone concentration of 35.5 mL/L, and further, treated at 50 0 C for 10 minutes while feeding a new ozone-containing gas. However, this method carries out only oxidation into a cystine crosslinked bond which performs main role of wool shrink proofing, and no reduction treatment is conducted. In the case of wool, a -S-S-bond is not cleaved until this reduction treatment and this cleavage gives satisfactory shrink 15 proofing to wool, therefore, sufficient shrink proofing and pilling resistance can not be obtained by the disclosed method. Further, the above-mentioned methods is conducted in a sealed system since the treatment should be conducted in an ozone gas atmosphere, and exposure is effected with the aid of molecular movement of an ozone gas, therefore, when the amount of wool treating is increased, unevenness of an ozone gas exposure can not be avoided, and this S* directly produces a unevenness treatment and uniform wool shrink proofing and dyeing are not obtained. At the same 25 time, in the above-mentioned method, the productivity is low due to the sealed system treatment, and when an ozone gas leaks directly out of the treating apparatus, deterioration in working environment and environmental charge are large, and industrialization is difficult.

Japanese Patent Kokai No. 142759/1980 discloses a method and an apparatus in which fiber is treated with an ozone-steam mixed material. In this method, worsted knitted fabric made of keratinous animal fiber is suspended on a belt conveyor circulating in a special treatment apparatus equipped with an exhaust apparatus, steam is introduced in this apparatus to increase the temperature to 79 0 C, a fan is started to introduce an ozone-air mixed gas (ozone introduction amount: 3.4 g/minute) and this mixed gas retained in the apparatus for 8.25 minutes to impart shrink proofing. Also in this method, only ozone oxidation is conducted, and no reduction treatment is effected.

Therefore, the imparted shrink proofing is not satisfactory, 15 and further, an ozone gas tends to leak due to the defective construction of apparatus, inviting deterioration in working environment.

Japanese Patent Kokai No. 19961/1991 discloses a method of shrink proofing of animal fiber using ozone as an oxidizer. It describes that an ozone gas is passed through a glass filter to give fine bubbles, in a water bath, and this bubbles are allowed to contact animal fiber. But bubbles generated through a glass filter or the like are too large to render ozone gas bubbles to reach fine 25 portions in a fiber assembly, and treat only the surface of the fiber assembly. It is well known from experience that when a wool product containing about 90% of shrink-proofed wool fiber and about 10% of non-shrink-proofed wool fiber in mixture is washed in water, it is shrunk in the same extent as a non-shrink-proofed wool product, whereas, in the above-mentioned method, an unevenness exposure on wool by an ozone gas makes a unevenness treatment, and sufficient shrink proofing is not obtained due to this unevenness.

Japanese Patent Kokai No. 72762/1998 discloses a method in which fiber is immersed in the form of tow, thread, fabric, knit fabric and the like into a waterdissolved ozone prepared by dispersing in water an ozonecontaining gas composed of ozone and oxygen or air in the form of bubbles having a diameter of 0.08 mm or less. It describes a method in which an ozone-containing gas is introduced in water to form bubbles, this bubbles are is broken by allowing it to collide against small walls in a line mixer when it passes through the line mixer, to give fine bubbles having a diameter of 0.08 mm or less showing enhanced solubility in water, for obtaining ozone dissolved in water having high concentration. This is merely a method for treating rayon and other fiber using ozone dissolved in water.

In the present invention, sliver composed of animal •fiber is, first, primary-oxidized with an oxidizer having an ability to oxidize a cystine -S-S-bond of the animal 25 fiber, and then, an ozone-oxygen mixed gas is made into ultrafine bubbles of 5 p or less in water by using a line mixer and the gas in this condition is allowed to collide against the previously primary-oxidized animal fiber for a 6 given time to cause a gas-phase oxidation reaction in the liquid, resulting in oxidation of the cystine bond of wool into higher order oxidized state without using a chlorine agent. Then, a reduction treatment is performed on the higher order-oxidized animal fiber to cleave the cystine crosslinkage and resultantly, combined effect of shrink proofing and pilling resistance can be continuously imparted to the sliver of animal fiber. The present invention has been made based on this detection.

SUMMARY OF THE INVENTION The present invention provide a method which imparts higher shrink proofing and pilling resistance simultaneously, without using a chlorine agent or a resin containing chlorine and without losing hand-feeling and 15is water repellency to animal fibers.

The present invention relates to a method for treating animal fiber comprising; a) a first step in which a bond (cystine bond) in the cuticle cell of an animal fiber is treated by 20 primary oxidation into lower order oxidized state, b) a second step in which the primary-oxidized -S-Sbond is treated by oxidation into any one or more higher order oxidized states of di, tri or tetra-oxidized state, and 25 c) a third step in which said bond in di, tri or tetra-oxidized state is treated by reduction fission.

Particularly, the present invention relates to a method for treating animal fiber comprising; a) a first step in which a bond in the cuticle cell of an animal fiber is treated by primary oxidation with an oxidizer having an ability to oxidize a cystine -S- S-bond in animal fiber, b) a second step in which the primary-oxidized -S-Sbond is treated by oxidation with ozone into any one or more higher order oxidized states of di, tri or tetraoxidized state, and c) a third step in which said bond in higher oxidized state is treated by reduction fission.

More specifically, the present invention relates to the above-mentioned method for treating animal fiber in which the first step is conducted according to a pad steam method.

15 Further specifically, the present invention relates to the above-mentioned method for treating animal fiber in which the oxidation treatment with ozone is conducted by blowing aqueous milky-like ozone treating liquid containing ozone in the form of ultrafine bubbles of 5 p or less to 20 animal fiber in this ozone treating liquid.

In the present invention, the primary-oxidized state of a cystine bond namely, lower order oxidized state means mono-oxidized state di-oxidized state (-S0 2 or mixed state thereof. Particularly, it means 25 the state rich in mono-oxidized state. While, the higher order oxidized state means di-oxidized state, tri-oxidized state (-S0 2 tetra-oxidized state (-S0 2 or mixed state thereof.

It is known that though fission of a bond by a reducing agent is not easy and requires a longer time in the case of mono-oxidized state, while in di, tri or tetraoxidized state, fission is effected relatively easily.

The present invention is characteristic in that it effects two-stage oxidation comprising a first step in which animal fiber is subjected to primary oxidation treatment by pad steaming with an oxidizer having an ability to oxidize a cystine bond of the animal fiber and a second step in which higher order oxidation is conducted by blowing aqueous treatment liquid containing ozone in the form of ultrafine bubbles of 5 p or less in the aqueous treatment liquid, for cleaving a cystine bond only in cuticle portions of animal fiber effectively, namely, in a short period of time without unevenness treatment.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view of a processing apparatus used in a method of the present invention.

20 Fig. 2 is a view illustrating an ozone treatment method.

Fig. 3 is a high evacuated state scanning electron micrograph of the surface of non-treated wool (dry condition).

25 Fig. 4 is a low evacuated state scanning electron

*S

micrograph of the surface of non-treated wool (wet condition).

Fig. 5 is a low evacuated state scanning electron micrograph of the surface of wool (wet condition) treated in Example i.

DETAILED DESCRIPTION OF THE INVENTION Various oxidation methods on animal fiber are compared and considered as follows.

A) In the case of oxidation only by ozone treatment: 1) Ozone has extremely low solubility in water, and it is 39.4 mg/L at OOC, 13.9 mg/L at 25 0 C and 0 mg/L at 60 0

C,

and from the standpoint of continuous treatment of animal fiber sliver, the treatment time becomes too long, being not suitable for the continuous treatment. 2) A large amount of an aqueous solution containing dissolved ozone is required. 3) An apparatus generating ozone of high concentration is necessary, increasing equipment investment.

4) when an ozone gas of high concentration is used, a careful caution is required on an exhaust gas and working environment at the spot.

B) In the case of comparison of an immersion method with a pad steam method, regarding oxidation of potassium hydrogen S 20 persulfate and the like: 1) An ionic bond (-NH 3 -OOC-) is one of bonds stabilizing molecular chains in animal fiber, and as the ooooo result that chemicals such as potassium hydrogen persulfate is reacted at higher temperature for a longer period of time in an immersion batch method, they permeate and are diffused into inner portions of fiber as acidic dyes do, and whole fiber is oxidized, a bond is cleaved, strength, elongation and the like decrease, resultantly, no shrink proofing effect is obtained.

2) On the other hand, in the method in which animal fiber is oxidized only by pad steaming using potassium hydrogen persulfate, immersion in padding operation is conducted under condition wherein animal fiber and potassium hydrogen persulfate do not react. Therefore, the temperature of an aqueous solution of potassium hydrogen persulfate (stabilization temperature of the aqueous solution, 20'C or lower) is lowered, immersion in this aqueous solution is effected for a short period of time (2 to 3 seconds) using wetting agent at lower temperature, and immediately, the animal fiber is impregnated with a certain amount of potassium hydrogen persulfate by squeezing with a mangle, and then, this is heated by steaming, resultantly, a reaction can be conducted only in portions wherein the animal fiber contains the reagent. In this method, since the cuticle tissue of animal fiber has larger content and is harder tissue than the inner tissue, the reagent :eoeoe does not invade into inner portions of the fiber but results only in surface layer oxidation and the inner tissue is protected, contributing to shrink proofing and pilling resistance indicating modification in the surface 0: tissue corresponding to the object of the present invention.

C) In the case of ozone treatment after pre-treatment with an oxidizer such as potassium hydrogen persulfate and the like: 1) Once an animal fiber is primary-oxidized, it is easily oxidized quickly with ozone, oxidation on animal fiber is completed in a short period of time, and continuous treatment is made possible. 2) Due to previous primary-oxidation, an oxidation reaction is promoted sufficiently with ozone of lower concentration, and consequently, a continuous treatment of animal fiber sliver becomes possible sufficiently by an apparatus generating ozone of lower concentration. 3) Due to the apparatus generating ozone of lower concentration, working environment does not deteriorate. 4) Owing to the apparatus generating ozone of lower concentration, equipment investment may be small.

As described above, the two-stage oxidation method of the present invention enables unexpected effective oxidation which has not been obtained by oxidation treatment either with an oxidizer or ozone.

In the present invention, as described above, a cystine bond is cleaved uniformly by higher order oxidation of animal fiber and the followed reduction treatment, and resultantly, animal fiber endowed uniformly with shrink proofing and pilling resistance is obtained by continuous steps. In the treated animal fiber obtained thus, fatty acids having a lot of carbon atoms revealing water repellency constituting the outermost surface of the fiber, particularly, eicosanoic acid is connected with an epicuticle layer (cystine content: 12%) via a thioester bond, and further, the epicuticle layer and an exocuticle A layer (cystine content: 35%) adjacent to the lower side of the epicuticle layer form an integrated structure, occupying about 20% of the total thickness of the cuticle, and cystine bonds are distributed in this tissue concentrically in an amount of about 70% based on the whole cystine content of the cuticle. The remaining about 30% is said to be composed of an exocuticle B layer (cystine content: 15%) and an endocuticle (cystine content: In oxidation treatment using potassium hydrogen persulfate, the exocuticle B layer is selectively attacked and the integrated structure of epicuticle and exocuticle A layers which is a structurally hard tissue is preserved, and resultantly, eicosanoic acid revealing water repellency is also kept and water repellency of the whole fiber, and fiber strength is also maintained, though it depends on the kind of an oxidizer. On the other hand, when animal fiber is treated with a chlorine agent or hydrogen peroxide, the ;i integrated structure of epicuticle and exocuticle A layers is directly attacked, particularly, an injure of the epicuticle is severe, and this phenomenon is recognized also by observation with an electron microscope.

Animal fiber is constituted of cuticle and cortical tissue, and the present invention provides a method for chemical modification mainly of cuticle tissue. Cuticle is arranged like a roof tile, and a piece of scale is constituted of tissue made of several layers. That is, the outermost surface is composed of epicuticle (cystine content: and the epicuticle further has an outer surface covered by a tissue having a thickness of 0.9 nm formed by a thioester bond between a fatty acid (eicosanoic acid) having water repellency and a -SH residue of an adjacent polypeptide chain, while, the lower side of the epicuticle is constituted of an exocuticle A layer (cystine content: 35%) and an exocuticle B layer (cystine content: and endocuticle having lower cystine content (cystine content: and cement (cystine content: connecting cuticle mutually and connecting cuticle with cortical tissue situated lower than the exocuticle layers.

The present invention is characteristic in two-stage oxidation comprising a first step in which animal fiber is primary-oxidized and a second step in which the primaryoxidized animal fiber is higher order-oxidized.

More specifically, first, an oxidizer having an ability to oxidize mainly a bond of animal fiber is used to effect pre-oxidation by a pad (impregnation)-steam (reaction) method, in some occasions, by pad-store (reaction at room temperature), depending on the kind of an oxidizer. When potassium hydrogen persulfate is used, preoxidation is conducted by the pad-steam method to primaryoxidize a lower side part of epicuticle and adjacent tissue called an exocuticle A layer, namely, an exocuticle B layer (first step). The tissue of the epicuticle part has extremely high cystine crosslinked density, has very high hardness, protects the inner portions of animal fiber, and manifests chemical resistance and abrasion resistance, and this epicuticle part is tissue last decomposed even by hydrolysis with 6N-hydrochloric acid. Therefore, epicuticle is handled as a resistant membrane in histology.

14 Then, a mixed gas of ozone and oxygen produced from an ozone generating apparatus is blown in a liquid circulation pump, further, aqueous ozone treatment liquid containing ozone in the form of ultrafine bubbles of 5 p or less is prepared through a line mixer, this liquid blown in water on animal fiber primary-oxidized, to ozone-oxidize quickly and preferentially an exocuticle B layer in which a cystine bond has been previously oxidized to give higher order oxidized state in the B layer.

Then, a cystine bond is cleaved by reduction treatment with a reducing agent, for example, a sulfite, to lower the cystine crosslinked density of the exocuticle B layer, as a result, swelling, fluidization and solubilization with water are promoted and a part of protein is allowed to flow out of the fiber, The felting phenomenon of animal fiber depends on S. bilateral property of an exocuticle B layer and endocuticle of cuticle tissue. Namely, most of cuticle tissue is composed of an exocuticle A and B layers and endocuticle, 20 and the exocuticle A layer form an integrated tissue structure with epicuticle, and the felting phenomenon depends, substantially, on the exocuticle B layer and endocuticle. The exocuticle B layer has a cystine content of 15% and the endocuticle has a cystine content of 3%.

When animal fiber is immersed in water, the endocuticle having lower cystine crosslinked density is swollen with water for expansion, and resultantly, scale (squama, cuticle) of animal fiber protuberates like being pushed up from the bottom, the tip of the scale uprises, resulting in entangling of fiber with fiber, causing felting.

In the present invention, the cystine crosslinked density of this exocuticle B layer is reduced by performing pre-oxidation, ozone oxidation and reduction treatment with a sulfite, about the same level water swelling as that of the endocuticle is obtained, bilateral function of the exocuticle B layer and endocuticle is allowed to disappear, the tip of scale does not uprise even when animal fiber is immersed in water, and shrinkage does not occur in aqueous washing. Simultaneously, a method has been found in which higher degree of shrink proofing is given without deteriorating water repellency since a thioester of eicosanoic acid covering an epicuticle layer and the surface thereof is still kept, and further, since scale is kept in the fiber, withdrawing force of pulling out of a fiber in the fiber assembly is higher and fiber movement in the fiber assembly is suppressed, resulting in correspondingly anti-pilling, as compared with a shrink proofing method in which scale is peeled, de-scaled or a shrink proofing method in which the surface of scale is coated with a resin.

While, in a chlorination reaction of animal fiber, a cystine bond is oxidized and hydrolyzed to give sulfonic acid (-SO 3 and since a peptide chain constituting wool fiber is cleaved in addition to cleavage of a cystine bond, the tensile strength and elongation of fiber are lowered. Also thioester bond tissue formed between eicosanoic acid which is the outermost film of wool fiber and a -SH group in a polypeptide chain is broken, to convert a hydrophobic structure into a hydrophilic group.

Therefore, water repellent function inherent to wool disappears.

A reaction mechanism by a chlorination reaction is shown below.

HOCI

2 SO 3

H

CONH CONH -NH 2 I and indicates a polypeptide chain.) The first step in the treatment method of the present invention is a pre-treatment step for oxidation of a cystine bond with ozone, and is a stage in which a cystine bond in cuticle tissue of the fiber is primary-oxidized with an oxidizer having an ability to oxidize a bond of animal fiber to obtain substantially mono-oxidized state.

Usually, when potassium hydrogen persulfate is used, an immersion method is adopted, and in this case, a treating reagent permeates into inner portions of fiber and the :fiber or whole fiber is oxidized and hydrolyzed to cleave a cystine bond, causing reduction in mechanical properties such as strength, elongation and the like. Nevertheless, shrink proofing effect is not obtained. Further, in a method in which potassium hydrogen persulfate is padded (impregnated) and stored (left at room temperature), reaction with the fiber does not occur and cuticle is not oxidized sufficiently unless the reaction temperature is room temperature or more (substantially, 320C) In the present invention, the treatment condition should be set depending on the kind of an oxidizer used and reactivity thereof with the fiber, and in the case of use of potassium hydrogen persulfate, the pad (impregnation)-steam (reaction with heat) method oxidizes a cystine bond only in cuticle portions while preventing oxidation of inner portions of the fiber, thereby, makes easy the subsequent higher order oxidation of cuticle portions with ozone.

Namely, in the first step of the present invention, a wetting agent is put into a bath charged with an oxidizer aqueous solution, the bath temperature is controlled as lower as possible than room temperature, padding (i impregnation) is effected so that liquid contact time with animal fiber will be several seconds (about 2 to 3 seconds), the fiber is removed out of the pad bath at a stage wherein the oxidizer aqueous solution does not reach inner portions of the fiber and sufficiently permeates into cuticle, and immediately, squeezed by a mangle so that add-on amount of the oxidizer aqueous solution becomes constant. The fiber ooooo thus containing a given amount of the oxidizer aqueous solution is subsequently treated at temperatures around 25 95C in steamer, for promoting a primary oxidation reaction while avoiding drying of the fiber.

Herein, the term "padding" does not mean impregnation of liquid into fiber by merely putting the fiber in a bath 18 but means impregnation so as not to cause a reaction in the immersion bath in view of chemical reactivity of the oxidizer used with animal fiber. It means poor reaction conditions, namely, selection of a wetting agent having S high permeability which is not decomposed with an oxidizer in a bath, control of the temperature in a bath as low as possible to suppress a reaction with fiber, and immersion for a short period of time such as several seconds and subsequent immediately squeezing. As the oxidizer used, per-acids such as persulfuric acid, peracetic acid and performic acid, neutral salts or acidic salts of these peracids, or potassium permanganate, hydrogen peroxide and the like are preferable, and these can be used alone or in admixture of two or more.

The second step in the treatment method of the present invention is a stage in which animal fiber primary-oxidized with an oxidizer is higher order-oxidized with ozone.

Usually, in oxidation with ozone, a longer period of time o is required, and formation of oxidation state sufficient for cleaving of a cystine bond is difficult. That is, when animal fiber is oxidized with ozone, it is necessary to treat the animal fiber with an ozone gas or ozone dissolved ooooo in water of high concentration for 10 to 30 minutes, and under such conditions, continuous treatment was impossible.

However, in the present invention, higher order oxidation with ozone in a short period of time with easiness has been made possible by conducting primary oxidation in the first step as a pre-treatment method and rendering ozone into specific state and simultaneously contriving contact method with fiber, and thus continuous treatment step has become possible.

Namely, the present invention is characteristic in that ozone is dispersed in the form of ultrafine bubbles of p or less at high concentration in water, and further, this aqueous treatment liquid containing ozone in such state is blown to animal fiber, to cause a gas-solid reaction with gas phase of ozone.

Development of an ultrafine bubbles scatter-preventing apparatus which collects ultrafine bubbles of 5 a or less discharged from a line mixer on the surface of a perforated suction drum and the increase of the number of collision of the ultrafine bubbles against fiber also contributed to s15 completion of the present invention.

i In oxidation treatment with ozone in the form of bubbles dispersed in water, the presence of bubbles in water, in general, prevents wetting of fiber assembly with liquid and exerts a reverse influence on wettability of liquid. In the present invention, as means for solving this drawback, a means is adopted in which, first, top sliver of animal fiber is sufficiently fiber-opened by a rotary gill to form a thin web like belt, wound on the surface of a perforated suction drum, and an ozone-oxygen mixed gas is made into ultrafine bubbles of 5 p or less by using a line mixer, and the liquid is sucked to increase the number of collision against fiber for allowing this ultrafine bubbles to penetrate between fiber and fiber, thereby promoting ozone oxidation.

The present invention will be illustrated in detail according to a process shown in Fig. 1. The animal fiber sliver used is, for example, a top of about 25 g/m, and the nine ends of tops are fiber-opened using a gill to form a belt, and the draft ratio is from about 1.4 to 4-fold, preferably 1.66-fold, though it varies depending on fineness of wool. The feeding speed of a wool top is from 0.2 m/min to 4 m/min, preferably from 0.5 m/min to 2 m/min.

The wool top shaped in the form of a belt is immersed in an aqueous solution containing an oxidizer and wetting agent, and squeezed with a squeezing mangle. Examples of the oxidizer include persulfuric acid, persulfates or acidic persulfates such as potassium hydrogen persulfate, sodium hydrogen persulfate, ammonium persulfate, potassium persulfate and sodium persulfate; potassium permanganate, hydrogen peroxide, performic acid or salts thereof, I peracetic acid or salts thereof, and the like.

Particularly preferable is potassium hydrogen persulfate 20 [trade name: "Oxone" (2KHSO 5 *KHSO* K 2

SO

4 active composition is 42.8% as the proportion of KHSOs); manufactured by E. I. du Pont de Nemours and Company] since it is in the form of a granule, easily dissolved, and an aqueous solution containing the dissolved oxidizer is stable for storage at a temperature of 32 0 C or less. As the wetting agent, "Alcopol 650" (manufactured by Chiba Special Chemicals is preferable since it is stable against an oxidizer. The concentration of the oxidizer is from 10 g/L to 50 g/L, preferably from 20 g/L to 40 g/L when the squeezing ratio is 100% in the case of potassium hydrogen persulfate "Oxone", though it differs depending on the kind of the oxidizer. The concentration of the wetting agent is suitably about 2 g/L in the case of "Alcopol 650".

The temperature of the pad liquid is preferably as low as possible so as not to cause a reaction in the liquid.

Particularly preferably, it is from 15°C to 25°C. It is preferable that pH of the liquid is on acidic side. More preferably, pH is After squeezing by a squeezing mangle, an oxidizer is allowed to react with animal fiber sliver, and the treatment conditions vary depending on the kind of the oxidizer. For example, in the case of potassium permanganate, hydrogen peroxide, performic acid or peracetic acid, a method in which an aqueous solution of these compounds is padded, and then, stored at room temperature is recommendable. The store time may advantageously be about 2 to 10 minutes though it varies 20 depending on the kind and concentration of the oxidizer.

While, in the case of potassium hydrogen persulfate, potassium persulfate, sodium persulfate or ammonium persulfate, a primary oxidation reaction may advantageously be conducted by steaming treatment at normal pressure, after padding of an aqueous solution of these compounds.

Regarding the steaming condition, a temperature of 95°C and a time from 5 to 15 minutes, preferably of about 10 minutes are sufficient to conducting primary oxidation.

One characteristic of animal fiber is that the cystine content varies depending on tissues constituting cuticle and cortex. In the present invention, particularly modification of cuticle tissue is conducted for imparting shrink proofing and pilling resistance Oxidation of a cystine bond progresses sequentially as described below, and the bond is cleaved after hydrolysis and reducing treatment, and finally, sulfonic acid (-SO 3 H) is obtained.

II 11 II iI II iI S- S- S I II I I I O O O O mono-oxidation di-oxidation tri-oxidation tetra-oxidation The present invention has a feature in that a reaction 0 15 is effected by a pad-steam method with an oxidizer, for example, potassium hydrogen persulfate, a bond is stopped at substantially mono-oxidized state, and is further oxidized to higher order using ozone in the subsequent step.

20 By adopting this operation, the ozone oxidation reaction rate increases remarkably as compared with oxidation rate when ozone is solely used or potassium hydrogen persulfate is solely used, and continuous treatment of animal fiber sliver becomes possible for the first time, leading to success in industrialization, if a S-S- bond is primary-oxidized previously, and then, ozoneoxidized, as shown in the following formula: O O

KHSO

5 11 03

S-S--

II

o The present invention is characteristic in that an ozone-oxygen mixed gas is allowed to collide against animal fiber sliver by blowing the gas in the form ultrafine bubbles of 5 p or less in water, to cause a gas phase reaction. Regarding the ozone generating apparatus, an ozonizer apparatus manifesting a generating capacity of about 250 g/hr (for example, one manufactured by Chlorine Engineering can sufficiently effect continuous treatment of animal fiber sliver, and for example, an ozone gas generated by feeding an oxygen gas at a rate of L/min into the ozonizer has a weight concentration of es wt% and a volume concentration of 0.1 g/L in the mixed gas,

S

and in one example, treatment with an ozone oxygen mixed gas of 4 g/min was an optimum condition though it differs depending on the extent of primary oxidation and other conditions. The feeding amount for imparting shrink proofing and pilling resistance to wool fiber is 6%owf or less, preferably from 1.5%owf to 5%owf based on the weight

S

of wool, though it differs depending on the wool fiber quality.

It is one feature of the present invention that, for reacting an ozone gas efficiently with wool, the ozone gas is formed into bubbles which are as fine as possible in water, the bubbles are allowed to collide against wool, and an oxidation is caused at the collision site. Therefore, also since the water solubility of ozone is extremely low, only cuticle tissue of wool is resultantly oxidized, and cortical tissue which is inner tissue is protected, resulting in further enhancement of the effect to modify the surface of wool. As the method for making an ozoneoxygen mixed gas into ultrafine bubbles of 5 p or less, a method is preferable in which the mixed gas is introduced into a water flow pump and the mixed gas is allowed to collided against small walls in a cylinder by raising water pressure to give ultrafine bubbles.

It is also a characteristic of the present invention that a special apparatus shown in Fig. 2 was contrived for collecting ultrafine bubbles produced in a line mixer and 15 blowing the bubbles on wool sliver in the form of a belt.

ego.oi Wool sliver in the form of a belt which has been primary-oxidized is sandwiched between stainless mesh belts and and transferred to an ozone treatment bowl (9) equipped with a suction drum where the ultrafine 20 bubbles are blown on wool sliver in the form of a belt through a nozzle from a line mixer And for collecting this ultrafine bubbles at the wool sliver in the oo o.o form of a belt, an ultrafine bubble-collecting apparatus 0(4) is mounted on the periphery of a suction drum, and ee 25 further, liquid containing the ultrafine bubbles is sucked from the center portion of the suction drum to allow the ultrafine bubbles to collide against the wool sliver in the form of a belt. An ozone-oxygen mixed gas produced from an ozonizer (11) is introduced in a water suction pump (12) to cause gas-liquid mixing, and the mixture is fed to the line mixer (13) by raising water pressure to produce ultrafine bubbles which are blown on wool sliver in the form of a belt sandwiched between stainless mesh belts.

Further, surface oxidation of wool fiber is completed by using an apparatus sucking through a suction port (7) Though it is said that ozone is a strong oxidizer second to fluorine, the nature is different at the acidic side and alkaline side. Namely, at the acidic side; 03 2H+ 2e 02 H20 E 2.07 V while, at the alkaline side; 03 H20 2e 02 20H- E. 1.24 V and, standard oxidation potential is higher, and further, solubility of ozone in water is higher and the half life is by far longer, at the acidic side.

(half life is 1 second when pH is 10.5 and 105 seconds when pH is The present invention is conducted at the acidic side 20 of pH 1.5 to pH 2.5, preferably, of pH 1.7 to pH Ozone has higher solubility, however, lower reactivity, in cold water. The treatment temperature has to be increased ooooo for enhancing the reactivity, and the treatment temperature may advantageously be 30 0 C to 50 0 C, and when it is too high, an ozone-oxygen mixed gas shows higher molecular movement, and is scattered out of a treatment bowl. Particularly preferable temperature is 40 0 C. The reaction time can control the reaction by the feeding speed of wool sliver, namely, the liquid contact time in the ozone treatment bowl.

When the feeding speed of sliver is 0.5 m/min, the contact time is 2 minutes, and when 2 m/min, the contact time is 33 seconds, and control of shrink proofing and control of pilling resistance are possible by controlling the reaction time.

The wool sliver ozone-oxidized in the ozone treatment bowl is treated with a reducing agent, and therein, a -S-Sbond is cleaved for the first time as shown in the following formula.

0 I NaHS03

-SO

2 H -SSO 3 Na

O

*In this method, particularly an exocuticle B layer among cuticle tissues, is attacked, and consequently, the cystine crosslinked density decreases and swelling property with water increases to the same water swelling level as that of endocuticle, and_consequently, bilateral property of scale of animal fiber disappears, preventing arising of scale in water (Figs. 4 to Therefore, water repellent function which is a characteristic of wool is not lost, and higher degree of shrink proofing and pilling resistance can be imparted while keeping water repellency.

The reducing agent is not particularly restricted, and sulfites are suitable. Among sulfites, sodium sulfite Na 2

SO

3 (pH 9.7) is more preferable than acidic sodium sulfite NaHSO 3 (pH Since primary oxidation and ozone 27 oxidation are conducted at the acidic side, reduction treatment at the alkaline side is preferable also from the standpoint of neutralization treatment. The concentration of sodium sulfite is preferably from 10 g/L to 40 g/L, and particularly preferably around 20 g/L. The temperature is preferably from 35 0 C to 45 0 C, and particularly preferably around It is preferable to conduct water rinsing in two steps while effecting over flow, both for removing the remaining sulfite and for removing protein dissolved from the treated wool. The temperature may advantageously be about 40 0

C.

After water rinsing, a softener and spinning oil agents may be added to the final bowl in view of handfeeling and spinning property of wool sliver. For example, S 15 treatment can also be conducted at 40 0 C by adding ooooo 1 g/L of Alcamine CA New (manufactured by Chiba Specialty Chemicals and 1 g/L of Croslube GCL (manufactured by CTC Textiles Ltd./Miki K.K.) S- 20 Drying is conducted preferably at relatively lower temperatures around 80 0 C in a suction type drier for a..

avoiding heat yellowing.

The following examples and comparative examples further illustrate the present invention more specifically, but the examples do not limit the scope of the present invention essentially, and any of suitable modifications in the range applicable to the above-mentioned aspects is contained in the technical range of the invention.

Example 1 Wool sliver was treated continuously according to a process diagram described in Fig. 1. The running speed of the sliver through processes, namely, a pad treatment mangle, ozone treatment bowl, reducing treatment bowl, water rinsing treatment bowl and drying processes was 2 m/min [Pad treatment process] 9 ends of sliver (25 g/m) made of Merino wool of 20.7 p from Australia were transferred to a rotary gill, and the wool sliver was fiber-opened into a belt by drafting at a ratio of 1.66. The belt sliver was padded in an aqueous solution having the following composition and squeezed by a mangle.

Pad aqueous solution composition Potassium hydrogen persulfate KHSOs concentration is g/L I ("Oxone", manufactured by E. I. du Pont de Nemours and Company) Wetting agent "Alcopol 650" concentration is 2 g/L (manufactured by Chiba Special Chemicals K.K.) Treatment Condition Contact time: 2 seconds Temperature: ordinary temperature pH: Squeezing rate: 100% It was squeezed by a mangle, and then, transferred to a steam treatment process.

[Steam treatment process] Wool sliver wetted in the form of a belt was subjected to steam treatment on a conveyor net under the following conditions.

95 0 C, 10 min After the steam treatment, the sliver was transferred to an ozone treatment bowl.

[Ozone treatment process] The steam-treated sliver was transferred to a suction type ozone treatment bowl, and ozone-oxidized under the following conditions.

Ozonizer ("OZAT CFS-3", manufactured by Chlorine Engineering was used at 250 g/hr, and an oxygen bomb was used as an oxygen source.

Oxygen feeding speed to "Ozonizer OZAT CFS-3"; L/min Ozone generation weight concentration; 6.5 wt% o* Ozone generation volume concentration; 0.1- g/L Ozone generation amount; 4 g/min Apparent ozone feeding amount to wool; 1.48%owf g/mX9X1/1.66=135.5 g/m wool 135.5 g/mX2 m/minXcontact time 0.55 min (33 sec)=149.05 g wool 4 g/min (0 3 X0.55 min=2.2 g 03 2.2 g/149.05X100=1.48% owf 03 The generated ozone gas was transferred to four line mixers through 4 pumps having a water lifting amount of L/min. The ozone blowing amount in each line mixer was L/min, and the total amount was 40 L/min. The ultrafine bubbles were allowed to collide against on the wool sliver on the suction drum by blowing the bubbles using an ultrafine bubble-scattering-preventing apparatus as shown in Fig. 2, and further, the treatment liquid was sucked from inside of the drum and was circulated to the outer side of the drum for increasing the times thereof, and ozone treatment was conducted under the following conditions.

Ozone bubbles; ultrafine bubbles of about 5 u Treatment temperature; 40 0

C

pH; 1.7 (adjusted with sulfuric acid) Contact time; 33 seconds After the ozone treatment, the sliver was transported to a reducing bowl.

[Reducing treatment process] The ozone-treated sliver in the form of a belt was *.o treated under the following conditions in a suction type reducing bowl.

20 g/L; sodium sulfite Na 2

SO

3 pH; 9.7 Temperature; 40 C Contact time; 33 seconds After the reduction treatment, the sliver was transported to a water rinsing bowl.

[Water rinsing treatment bowl] The reduction-treated sliver in the form of a belt was treated with hot water of 40 0 C for 33 seconds in a suction type water rinsing bowl. After the water rinsing, the sliver was further transported to another water rinsing treatment bowl.

[Water rinsing treatment bowl] The sliver in the form of a belt was treated with hot water of 40°C for 33 seconds in a suction type water rinsing treatment bowl. After the water rinsing, the sliver was transported to the final bowl for imparting a spinning oil and softener necessary for the subsequent processes.

[Spinning oil and softener treatment process] The water-rinsed sliver in the form of a belt was treated with hot water of 40 0 C for 33 seconds in a suction type treatment bowl charged with the following treating agents.

Treating agent 1 g/L of "Alcamine CA New" (manufactured by Chiba Specialty Chemicals and 1 g/L of "Croslube GCL" (manufactured by CTC Textiles Ltd./Miki K.K.) After the oiling-treatment, the sliver was transported to a drier.

[Drying process] Drying was conducted at 80 0 C using a suction type hot air drier.

The treated sliver in the form of a belt was gilled and spun into hosiery yarn of 2/48Nm by twist of Z500XS300, and strength and elongation of the yarn were measured, and 32 knitted into a density of a cover factor (CF) of 0.41, and washed continuously for 1 hour and 3 hours by a Cubex shrinkage testing apparatus. The fabric which had been knitted into a CF of 0.41 was subjected to a pilling test for 5 hours by an ICI pilling tester. For further investigating the property of the treated wool fiber, the surface of the wool was observed by an electron microscope, S-3500N manufactured by Hitachi. For measuring the water repellency of the treated wool, the sliver was gilled to be fiber-opened, and each 1 g of the treated sliver and nontreated sliver was sampled, 800 mL of distilled water was charged into a l-L beaker and the sample was floated on the water surface and sedimentation condition was observed.

The results thereof are shown in Table 1 and Figs. 4 to 6.

The treated wool sliver was soft and showed white color, and shrink prcofing thereof met the standard of area shrinkage percentage under the Wool Mark washability requirment, and also, satisfied 4-th grade level of pilling resistance in the ICI pilling test. The observation of the sedimentation state of 1 g of the sample showed that both of the non-treated wool and the ozone-treated wool did not precipitate even after left for a day and night and were floating on water surface in the beaker, while, the wool treated by a chlorinated resin method (Chlorine Hercosett method) sank beneath water surface in the beaker only after left for 2 to 3 minutes. Though one of properties of animal fiber is that it has naturally water repellent function, in the present invention, an epoch-making experiment result was obtained that shrink proofing can be imparted without losing water repellent function owned by natural wool. In the conventional shrink proofing method, a method in which chlorine-treated wool surface is coated with a Hercosett resin (polyamide epichlorohydrin) is mainly used. On the wool treated thereby, water repellent function tends to be lost and the wool tends to be wetted and resultantly, body temperature is lowered due to high heat conductivity of water, giving chilled feeling to wearer, though shrink proofing is obtained. The surface of the treated wool was observed by using S-3500N low evacuated electron-microscope manufactured by Hitachi which can observe the object in wet condition showed that scale edge of the wool did not uprise, namely, differential 15 frictional effect was not found, and on the contrary, in the non-treated wool, scale of the wool uprose owing to swollen with water, which is a cause of felting.

Therefore, the present invention is a shrink proofing method which does not uprise scale edge of wool in water.

20 Comparative Example 1 A sliver of 20.7 p (25 g/m, 9 ends, draft ratio: 1.66fold) of Merino wool from Australia was continuously treated according to the method in Example 1 using.

SHowever, the ozone treatment using an ultrafine bubblescatter-preventing apparatus was omitted. The results thereof are shown in Table 1. Though the treated wool was bleached, shrink proofing and pilling resistance were approximately at the same level as those of the non-treated wool, and no treatment effect was appreciated.

From comparison of Example 1 with Comparative Example i, it became apparent that on wool which had been treated previously with potassium hydrogen persulfate as a pretreatment process, oxidation progresses quickly with a small amount of ozone. Namely, the present invention exemplified in Example 1 is an revolutionary method in which wool fiber can be modified to impart shrink proofing and pilling resistance with a small amount of ozone, and as the result, treatment effect is manifested sufficiently with a small capasity of ozonizer, and consequently, equipment investment decreases and exhaust gas treatment is reduced, and deterioration in working environment is prevented.

15 Comparative Example 2 A sliver of 20.7 a (25 g/m, 9 ends, draft ratio: 1.66fold) of Merino wool from Australia was continuously treated according to the method in Example 1 using.

However, the pre-treatment using potassium hydrogen persulfate was omitted. The results thereof are shown in Table i. Though the treated wool was somewhat bleached, shrink proofing and pilling resistance were completely at the same level as those of the non-treated wool.

Example 2 Sliver of 20.7 p of Merino wool from Australia was treated according to the method in Example 1. However, the transferring speed of the wool sliver was 0.55 m/min and the contact time of the treatment liquid for the wool sliver in the ozone treatment bowl and other treatment bowl was 2 minutes. The apparent ozone feeding amount to wool was 5.37%owf.

g/mX9X1/1.66=135.5 g/m wool 135.5 g/mXO.55 m/minXcontact time 2 min=149.05 g wool 4 g/min (0 3 )X2 min=8 g (03) 8 g/149.05gX100=5.37% owf 03 The treated wool sliver was gilled and spun into hosiery yarn of 2/48Nm by twist of Z500XS300, and knitted into a density of a cover factor (CF) of 0.41, and continuous washing tests for 1 hour and 3 hours by a Cubex shrinkage testing apparatus, and further, a pilling test for 5 hours using an ICI pilling tester were conducted, and S 15 strength and elongation of the knitted yarn were measured.

*For observing modification state of the surface of the wool, 1 g of the treated sliver was fiber-opened by a gill, 800 mL of distilled water was charged into a 1-L beaker and the sliver was floated on the water surface and sedimentation 20 condition was observed.

The results of the tests are shown in Table 1. The treated wool sliver was soft and also reveals whiteness, and further, by increasing the ozone feeding amount in Example 1 by about 3.6-fold, shrink proofing was by far

S.

lower than the Wool Mark washability requirement, and such high degree of pilling resistance that the result of an ICI pilling test was 5-th grade even after 5 hours was obtained.

Since the reaction amount of ozone was increased, strength and elongation of the knitted yarn somewhat decreased, and regarding water repellent resistance, in the case of chlorine-treated wool, completion precipitation to beneath water surface was observed, and this treated wool revealed slight reduction as compared with natural non-treated wool.

o o 9. 9.

*9* 9** 9* 9 9 9 9 9 9. 9 9 99 9 9 9 9 9 .9 9 .9 9 9* 9 9* 9 [Table 1] Knitted fabric having CF of 0.41 2/48Nm, z500XS300 Plig -Water repellency Hosiery yarn Felt shrinkage test etI) (Sn/laWheesHnd SrntElnain1hu 3hor 5hormethod), feeling StregthElonatin 1hour 3 hurs hors, visual observation M% (area (area grade______ The same as Example 1 266.8 11.9 -0.49 -0.99 4 naua olWhite Soft Examplenatural wool Comparative 31 636.1 7 .012The same as WieSf Example natural Example 2 258.9 9.0 3.71 -1.52 5 Somewhat reduced White Soft Non-treated 296.5 13.2 70.00 75.00 1 Wae eelny Cem Soft Iis recognized color Notice: minus ()in table indicates extention 38 In the present invention, the dimensional instability which has been a defect of animal fiber can be improved without losing water repellency which is a feature of the fiber and further without reducing fiber mechanical properties, and excellent shrink proofing and pilling resistance can be simultaneously imparted to the animal fiber, without using any harmful chemicals such as chlorine-based chemicals and the like. In addition, according to the present invention, continuous treatment is possible, and utility value is extremely high also in respect of industrialization.

The Japanese characters in Figures 3 and 4 mean "untreated wool" Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

e.

i The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion *that that prior art forms part of the common general knowledge in Australia.

0i 0 00 oe

Claims (8)

1. A method for treating animal fiber comprising; a) a first step in which a bond (cystine bond) in an animal fiber cuticle cell is treated by primary oxidation into lower order oxidized state, b) a second step in which the primary-oxidized -S-S- bond is treated by oxidation into any one or more higher order oxidized states of di, tri or tetra-oxidized state, and c) a third step in which said bond in di, tri or tetra-oxidized state is treated by reduction cleavage.

2. A method for treating animal fiber comprising; a) a first step in which a bond in an animal 15 fiber cuticle cell is treated by primary oxidation with an oxidizer having an ability to oxidize a cystine -S-S-bond in animal fiber, b) a second step in which the primary-oxidized -S-S- bond is treated by oxidation with ozone into any one or 20 more higher order oxidized states of di, tri or tetra- oxidized state, and c) a third step in which said bond in higher oxidized state is treated by reduction cleavage.

3. The method for treating animal fiber according to Claim 2 wherein the oxidizer is one or a mixture of two or more selected from the group consisting of persulfuric acid, peracetic acid, performic acid, neutral salts and acidic salts of these per-acids, potassium.permanganate and b hydrogen peroxide.

4. The method for treating animal fiber according to Claim 2 or 3 wherein the first step is conducted by a pad steam method.

5. The method for treating animal fiber according to any one of Claims 2 to 4 wherein the oxidation treatment with ozone is conducted by blowing aqueous ozone treating liquid containing ozone in the form of ultrafine bubbles of i or less to animal fiber in this ozone treating liquid.

6. The method for treating animal fiber according to any one of Claims 1 to 5 wherein the animal fiber is used as cloth or sliver mainly composed animal fibers.

7. The method for treating animal fiber according to any one of Claims 1 to 6 wherein the animal fiber is 15 selected from the group consisting of wool, mohair, alpaca, cashmere, llama, vicuna, camel and angora. :4.00, 0 .4 41

8. A method for treating animal fiber substantially as hereinbefore described with reference to the Examples and/or drawings. Animal fiber or an animal fiber product wherein the fiber has been treated by a method according to any one of the preceding claims. The steps, features, compositions and compounds disclosed herein or referred to or indicated in the specification and/or claims of this application, individually or collectively, and any and all combinations of any two or more of said steps or features. 00 5DATED this TWENTY FOURTH day of NOVEMBER 2000 S* *oo* DATED tby DAVIES COLLISON CAVE Patent Attorneys for the applicant(s) o