WO2000026447A1

WO2000026447A1 - Incorporation of organic anti-microbials into fibres during a fibre spinning process

Info

Publication number: WO2000026447A1
Application number: PCT/EP1999/007875
Authority: WO
Inventors: Jianwen Mao; Clement Gui Min Zhang; Frank Chao Ma; Marcel Schnyder
Original assignee: Ciba Specialty Chemicals Holding Inc.
Priority date: 1998-10-29
Filing date: 1999-10-18
Publication date: 2000-05-11
Also published as: EP1141453A1; CN1325462A; TR200101052T2; KR20010087382A; AU6473499A

Abstract

A process for finishing regenerated cellulose fibres with an anti-microbial and/or antifungal agent or a mixture thereof wherein in the first step, a formulation comprising an anti-microbial agent and one or more surface active agents are added to the soluble form of the fibres prior to regeneration and in a second step this mixture is extruded from a spinneret to form the regenerated fibre. The fibres treated according to the process of the present invention show good anti-microbial and antifungal activity.

Description

Incorporation of organic anti-microbiais into fibres during a fibre spinning process

The present invention relates to a process for the incorporation of antimicrobial agents, antifungal agents or mixtures thereof into fibres and the fibres resulting from this process.

There is an increasing demand for regenerated cellulose fibres, such as Rayon, and textile products made by such fibres including blends, that exhibit antimicrobial and/or antifungal properties, in order to inhibit the growth of bacteria and fungi which would cause health concern to the consumers as well as malodor to the textiles.

Antimicrobial textile finishing in the form of a surface treatment of the textiles is already known, however the antimicrobials can be easily washed off in the subsequent use of such textiles.

To achieve durability of such activity against multiple washings a preferable incorporation method would be to add antimicrobial active ingredients into the fibres. Technically the only feasible means of such an incorporation involves adding antimicrobials into the soluble form of the cellulose followed by extrusion from the spinneret to form soft filaments which are then regenerated into cellulose. Rayon's are wet spun which means that the filaments emerging from the spinneret pass directly into chemical baths for solidifying or regeneration.

However, in practice the incorporation of antimicrobials, especially organic antimicrobials, is found to be difficult because of the highly aggressive processing conditions involved in the production of Rayon fibres.

Incorporation of solid particles of the antimicrobial should not be included in the soluble form of cellulose as this may cause blockage of the spinneret. To overcome such a problem, a milling process would be required to sufficiently bring down the particle size of the antimicrobial. But such milling processes are often expensive and for some organic antimicrobials, very difficult because of their relatively low melting point.

Another rational approach would be to dissolve the antimicrobial in a solvent which is compatible with the soluble form of the cellulose. But the difficulty is that when the soluble form of cellulose is extruded from the spinneret, it passes directly into chemical baths in which the chemical reactions take place for regeneration of cellulose. If the antimicrobial is dissolved in an organic solvent, the antimicrobial would remain in the organic phase after regeneration. If the antimicrobial is dissolved in an aqueous solvent, the antimicrobial would remain in solution and leach out of the fibre during regeneration. Therefore unsatisfactory incorporation of the antimicrobial into the fibre usually occurs.

Surprisingly it was found that fibres with improved antimicrobial and/or antifungal activity are provided by a process in which antimicrobials, antifungals or a mixture thereof and one or more surface active agents are added into the soluble form of the cellulose, then the fibres are formed by extrusion from a spinneret and finally the fibres are regenerated into cellulose.

This invention relates to a process for finishing regenerated cellulose fibres with antimicrobial agents, antifungal agents, or a mixture thereof wherein in the first step, a formulation comprising an anti-microbial agent, an anti-fungal agent or a mixture thereof and one or more surface active agents are added to the soluble form of the fibres prior to regeneration and in a second step this mixture is extruded from a spinneret to form the regenerated fibre.

The antimicrobial agents are selected from the group consisting of

(a) halogeno-o-hydroxydiphenyl compounds;

(b) phenol derivatives;

(c) benzyl alcohols;

(d) chlorohexidine and derivatives thereof;

(e) Ci 2-C14alkylbetaines and Cs-Ci sfetty acid amidoalkylbetaines;

(f) amphoteric surfactants;

(g) trihalocarbanilides;

(h) quaternary and polyquaternary compounds; and (i) thiazole compounds;

Preferably, the antimicrobial agent (a) is selected from compounds of the formula

whe rein

X is oxygen, sulfur or -CH2-,

Y is chloro or bromo, z is SO2H, NO2 or Cι-C4-Alkyl, r is 0 to 3, o is 0 to 3,

P is 0 or 1 , m is 0 or 1 and n is 0 or 1 ; and at least one of r or o is ≠ 0.

Preferably, in the present process, antimicrobial agents (a) of formula (1) are used, wherein

X is oxygen, sulfur or -CH2-, and

Y is chloro or bromo, m is O, n is O or l ,

0 is 1 or 2, r is 1 or 2 and p is O.

Of particular interest as antimicrobial agent (a) is a compound of formula

wherein

X is -O- or -CH2-; m is 1 to 3; and n is 1 or 2, and most preferably a compound of formula Most preferably the antimicrobial agent is a compound of formula

Formula (3) shows the antimicrobial 2,4,4'-trichloro-2-hydroxydiphenyl ether, otherwise known as Triclosan. Formula (4) shows the antimicrobial 4,4'-trichloro-2-hydroxydiphenyl ether, otherwise known as Diclosan.

Preferred phenol derivatives (b) correspond to formula

wherein

Rl is hydrogen, hydroxy, C-|-C4alkyl, chloro, nitro, phenyl or benzyl,

R2 is hydrogen, hydroxy, C-|-C6alkyl or halogen,

R3 is hydrogen, C-|-C6alkyl, hydroxy, chloro, nitro or a sulfo group in the form of the alkali metal salts or ammonium salts thereof, R4 is hydrogen or methyl, and R5 is hydrogen or nitro.

Such compounds are typically chlorophenols (o-, m-, p-chlorophenols), 2,4-dichlorophenol, p-nitrophenol, picric acid, xylenol, p-chloro-m-xylenol, cresols (o-, m-, p-cresols), p-chloro-m- cresol, pyrocatechin, resorcinol, orcinol, 4-n-hexylresorcinol, pyrogallol, phloroglucine, carvacrol, thymol, p-chlorothymol, o-phenylphenol, o-benzylphenoi, p-chloro-o-benzylphenol and 4-phenolsulfonic acid.

Typical antimicrobial agents (c) correspond to the formula

wherein l , R2. R3. R4 and R5 ^{are eacn} independently of one another hydrogen or chloro.

Illustrative examples of compounds of formula (6) are benzyl alcohol, 2,4-, 3,5- or 2,6- dichlorobenzyl alcohol and trichlorobenzyl alcohol.

Antimicrobial agent (d) is chlorohexidine and salts thereof, for example 1 ,1'-hexamethylene- bis-(5-(p-chlorophenyl)-biguanide), together with organic and inorganic acids and chlorhexidine derivatives such as their diacetate, digluconate or dihydrochloride compounds.

Antimicrobial agent (e) is typically Cs-C-iβcocamidopropylbetaine.

Amphoteric surfactants as antimicrobial agents (f) are suitably C-|2alkylaminocarboxylic and Ci -C3alkanecarboxylic acids such as alkylaminoacetates or alkylaminopropionates.

Typical trihalocarbanilides which are usefull as antimicrobial agent (g) are compounds of the formula

wherein

Hal is chloro or bromo, n and m are 1 or 2, and the sum of n plus m equals 3.

The quaternary and polyquaternary compounds which correspond to antimicrobial agent (h) include those of the formula

wherein

Rθ. R7. Rδ and Rg are each independently of one another C-|-C-|8alkyl, Cι-C-|salkoxy or phenyl-lower alkyl, and

Hal is chloro or bromo.

Among these salts, the compound of formula

wherein n is an integer from 7 to 17, is very particularly preferred.

A further exemplified compound is cetyl trimethylethyl ammonium bromide.

Other important positively charged antimicrobial agents such as those known as quaternary ammonium compounds can also be included in such a process, in addition to provide the treated fibres with such agents, an additional advantage is that such agents would have good affinity to the cellulose substrates. Examples of such agents include compounds of the formula:

which is also known as Aegis DC5700, or a phosphate derivative of quaternary compounds of the formula: OC₄H₉

OC₄H₉- -P=0 l _ o

an epoxide derivative of the formula:

or an epichloride derivative known as Degussa Quab 342 of the formula:

Of particular interest as antimicrobial agent (i) is methylchloroisotahazoline.

A combination of antimicrobial agents that provide antibacterial and antifungal activities, are advantageous in that they provide the treated fibres with further functions such as antibacterial, antifungal, anti-dustmite and deodorising properties.

Compounds that exhibit antifungal properties and are suitable for such a process include;

- compounds containing a naphtyl ether group, preferably 2-naphthyl-N-methyl-N-(3- tolyl)thionocarbamate:

benzylimidazol derivatives, for example those known as Protectol BCM, of the formula:

benzoate derivatives, preferably benzyl benzoate:

It is noted that many other compounds that exhibit antifungal properties could also be suitable for such a process, as known to those skilled in the art. The examples provided above are not intended to limit the scope of the invention.

The process uses a formulation which is compatible with the aqueous solution of cellulose and which also facilitates incorporation into the fibres.

The antimicrobial agents or antifungal agents which are used in the present process are water-soluble or only sparingly soluble in water. These compounds are therefore applied in dispersed form. To this end, they are milled with an appropriate surfactant, conveniently using quartz balls and an impeller, to a particle size of about 1 -2mm or less. Antimicrobial agents so prepared could then be made into stable formulations by the addition of suitable dispersing or emulsifying agents.

As an important feature of this invention, it was found that the antimicrobials, antifungals or mixtures thereof can be dissolved in a surfactant at a concentration ranging from 1 to 60%. By selection of suitable surfactant or surfactants system with or without additional dispersing agents, a homogeneous mixture can be formed when the formulation is added to the soluble form of the cellulose.

The incorporation can be achieved by diluting the antimicrobial and/or antifungal surfactant solution to form a dispersion which is pumped into the cellulose solution just before extrusion. The concentration of antimicrobials and/or antifungals ranges from 10g to 100g per litre of solution, preferably 40g to 60 g per litre of solution.

Alternatively, concentrated antimicrobial and/or antifungal surfactant solution is directly pumped into the cellulose solution just before extrusion. This process requires precise metering and also very good mixing as the amount of antimicrobial and/or antifungal being incorporated into the fibres is very small.

Suitable surfactants for use in the present process are:

acid esters or their salts of alkylene oxide adducts, typically acid esters or their salts of a polyadduct of 4 to 40mol of ethylene oxide with 1mol of a phenol, or phosphated polyadducts of 6 to 30mol of ethylene oxide with 1 mol of 4-nonylphenol, 1mol of dinonylphenol or, preferably, with 1 mol of compounds which are prepared by addition of 1 to 3mol of unsubstituted or substituted styrenes to 1 mol of phenol, polystyrene sulfonates, fatty acid tau rides, alkylated diphenyl oxide mono- or disulfonates, sulfonates of polycarboxylates, the polyadducts of 1 to 60 mol of ethylene oxide and/or propylene oxide with fatty amines, fatty acids or fatty alcohols, each containing 8 to 22 carbon atoms in the alkyl chain, with alkylphenols containing 4 to 16 carbon atoms in the alkyl chain, or with trihydric to hexahydric alkanols containing 3 to 6 carbon atoms, which polyadducts are converted into an acid ester with an organic dicarboxylic acid or with an inorganic polybasic acid, ligninsulfonates, and, most preferably, formaldehyde condensates such as condensates of ligninsulfonates and/or phenol and formaldehyde, condensates of formaldehyde with aromatic sulfonic acids, typically condensates of ditolyl ether sulfonates and formaldehyde, condensates of naphthalenesulfonic acid and/or naphthol- or naphthylaminesulfonic acids with formaldehyde, condensates of phenolsulfonic acids and/or sulfonated dihydroxydi- phenylsulfone and phenols or cresols with formaldehyde and/or urea, as well as condensates of diphenyl oxide-disulfonic acid derivatives with formaldehyde.

A preferred surfactant is a nonyl phenyl ether of the formula

It is found that it is advantageous if a combination of two or more surfactants such as those listed above are included in the formulation.

During the second step the mixture is passed through the spinneret into the chemical baths, such as the coagulation bath which normally contain concentrated solutions of 5% to 15% sulfuric acid, preferably 7% to 12% sulfuric acid, where the regeneration of cellulose occurs. When the fibre comes into contact with the coagulation bath, the antimicrobials and/or antifungals quickly precipitate and form particles of very small size within the cellulose fibres. These particles are difficult to remove from the fibres and are small enough to avoid spinneret blockage.

The formulation may be used in the incorporation of antimicrobials and/or antifungals into synthetic fibres, and blends thereof, which are produced by wet spinning processes. Such fibres include rayon, cellulose acetate, cellulose triacetate, poly(vinyl chloride) and poly(acrylonitrile), or blends thereof.

The expected concentration of antimicrobial and/or antifungal in the fibres ranges from 0.1% to 3%, preferably 0.5% to 1%.

A further aspect of the invention provides the compositions used for the finishing process. The compositions comprise an antimicrobial, or a mixture thereof, selected from the following:

(a) halogeno-o-hydroxydiphenyi compounds;

(b) phenol derivatives;

(c) benzyl alcohols;

(d) chlorohexidine and derivatives thereof;

(e) Ci 2-C-14alkylbetaines and Cβ-Ci βfatty acid amidoalkylbetaines;

(f) amphoteric surfactants; (g) trihalocarbanilides;

(h) quaternary and polyquatemary compounds; and

(i) thiazole compounds;

and one or more surfactants selected from the following:

- acid esters or their salts of alkylene oxide adducts, typically acid esters or their salts of a polyadduct of 4 to 40mol of ethylene oxide with 1 mol of a phenol, or phosphated polyadducts of 6 to 30mol of ethylene oxide with 1 mol of 4-nonylphenol, 1 mol of dinonylphenol or, preferably, with 1mol of compounds which are prepared by addition of 1 to 3mol of unsubstituted or substituted styrenes to 1 mol of phenol,

- polystyrene sulfonates,

- fatty acid taurides,

- alkylated diphenyl oxide mono- or disulfonates,

- sulfonates of polycarboxylates,

- the polyadducts of 1 to 60 mol of ethylene oxide and/or propylene oxide with fatty amines, fatty acids or fatty alcohols, each containing 8 to 22 carbon atoms in the alkyl chain, with alkylphenols containing 4 to 16 carbon atoms in the alkyl chain, or with trihydric to hexahydric alkanols containing 3 to 6 carbon atoms, which polyadducts are converted into an acid ester with an organic dicarboxylic acid or with an inorganic polybasic acid,

- ligninsulfonates, and, most preferably,

- formaldehyde condensates such as condensates of ligninsulfonates and/or phenol and formaldehyde, condensates of formaldehyde with aromatic sulfonic acids, typically condensates of ditolyl ether sulfonates and formaldehyde, condensates of naphthalenesulfonic acid and/or naphthol- or naphthylaminesulfonic acids with formaldehyde, condensates of phenolsulfonic acids and/or sulfonated dihydroxydi- phenylsulfone and phenols or cresols with formaldehyde and/or urea, as well as condensates of diphenyl oxide-disulfonic acid derivatives with formaldehyde.

A preferred composition comprises 40g of a compound of formula (3) dissolved in 60g of a nonyl phenyl ether of the formula C₉H₁₉C₆H₅O(CH₂CH₂O)₁oH.

The composition may also additionally contain an antifungal agent. The concentration of the antimicrobial or antimicrobial/antifungal mixture ranges from 1 to 60%. A further composition comprises an antifungal agent selected from the following:

- a naphtyl ether derivative

- a benzylimidazol derivative

- a benzoate derivative

and a surfactant selected from the following:

- acid esters or their salts of alkylene oxide adducts, typically acid esters or their salts of a polyadduct of 4 to 40mol of ethylene oxide with 1 mol of a phenol, or phosphated polyadducts of 6 to 30mol of ethylene oxide with 1 mol of 4-nonylphenol, 1 moI of dinonylphenol or, preferably, with 1 mol of compounds which are prepared by addition of 1 to 3mol of unsubstituted or substituted styrenes to 1 mol of phenol, polystyrene sulfonates, fatty acid taurides, alkylated diphenyl oxide mono- or disulfonates, sulfonates of polycarboxylates, the polyadducts of 1 to 60 mol of ethylene oxide and/or propylene oxide with fatty amines, fatty acids or fatty alcohols, each containing 8 to 22 carbon atoms in the alkyl chain, with alkylphenols containing 4 to 16 carbon atoms in the alkyl chain, or with trihydric to hexahydric alkanols containing 3 to 6 carbon atoms, which polyadducts are converted into an acid ester with an organic dicarboxylic acid or with an inorganic polybasic acid, ligninsulfonates, and, most preferably, formaldehyde condensates such as condensates of ligninsulfonates and/or phenol and formaldehyde, condensates of formaldehyde with aromatic sulfonic acids, typically condensates of ditolyl ether sulfonates and formaldehyde, condensates of naphthalenesulfonic acid and/or naphthol- or naphthylaminesulfonic acids with formaldehyde, condensates of phenolsulfonic acids and/or sulfonated dihydroxydiphenyl- sulfone and phenols or cresols with formaldehyde and/or urea, as well as condensates of diphenyl oxide-disulfonic acid derivatives with formaldehyde.

These compositions may be diluted in order to form a dispersion, wherein the concentration of antimicrobial and/or antifungal is in the range of 10g to 10Og per litre, preferably in the range of 40g to 60g per litre. ln summary, the formulation and the use of such a formulation in the fibre production process results in fibres with improved antimicrobial and/or antifungal activity, no problems in spinneret blockage and also the antimicrobial activity and/or antifungal activity is difficult to remove as the antimicrobial/antifungal remains homogeneously dispersed in the fibres.

The following examples further illustrate the present invention.

Example 1 : Preparation of antimicrobial containing formulation

40 gram of Triclosan, the compound of formula (3), is dissolved in 60 gram of a nonyl phenyl ether of the formula C₉H₁₉C₆H₅O(CH₂CH₂O)₁oH. The resulting formulation (Formulation A) is a clear solution.

Example 2: Preparation of diluted formulation

100 gram of Formulation A is added into an appropriate amount of water (deionised) to produce a 800ml formulation. The resulting formulation (Formulation B) is a stable dispersion in which the concentration of Triclosan is 50g/litre.

Example 3: Preparation of antimicrobial containing rayon fibres

Cellulose in its' soluble form is prepared by a conventional process. Hence, sized cellulose is treated with caustic soda, oxidising and sulfonating agent and solublilised/pulverised to form aqueous solution followed by filtration and degassing. Soluble cellulose prepared as such is ready to be spun to form fibres. Formulation B is injected by a diaphragm pump into the main pipeline in which the soluble rayon is being transported to the spinneret for extrusion. The mixture of Formulation B and soluble rayon is further mixed in the pipe to improve homogeneity before it is extruded from the spinneret to form fibres. The pumping speed is adjusted as such that the resulting expected concentration of Triclosan in the fibres is in the range of 0.5 to 1 %.

The so-formed fibre is allowed to pass into a coagulation bath comprised of 10% sulfuric acid and then a stretching bath comprised of 1 % sulfuric acid in which coagulation and stretching take place followed by desulfonation, washing, oiling and drying.

Example 4: Concentration of Triclosan in the rayon fibres

3.5 g of the rayon fibres prepared by example 4 are extracted with 150 ml of methanol in a soxhlet apparatus under the following conditions: Temperature limit: 300°C

Extraction temperature: 290°C

Boiling time: 4 hours

Solvent reduction A: 5 x 15 ml

Extraction time: 6 hours

Solvent reduction interval: 4 minutes

Solvent reduction phase: 3 seconds

The extract is then used for reversed phase High Performance Liquid Chromatography analysis under the following conditions:

Instrument: HP1100 or other comparable systems

Column: Nucleosil 3C18, 70mm x 4.6mm ID, 40°C

Detector: UV at 280nm

Injection: 2.0μl

Flow rate: 0.20ml/min

Solvent: 50% Solvent A(acetonitrile) : 50% Solvent B(water), 100% solvent A at 20 minutes

Results: (Table 1)

The results show that the use of formulation A and B as claimed in this invention increases the amount of antimicrobial remaining in the fibres significantly. Example 5: Antimicrobial efficacy of rayon fibres treated with Triclosan

Purpose

The agar diffusion test is used to determine the bacteriostatic or fungistatic activity of an antimicrobial agent or a product which contains an antimicrobial or has been treated with an antimicrobial agent.

Principle

The treated material (usually in the form of discs) is applied on inoculated agar plates. During the incubation phase, the active substance can diffuse into the agar and inhibit the bacterial growth. Poorly diffusing products should at least be able to inhibit the bacterial growth under the disc.

The described agar diffusion test is based on the method AATCC 90-1974. Other methods which are based on diffusion / inhibition principle are:

- SNV 195'920; Testing the antibacterial effect of textiles and other materials with the help of agar diffusion tests (1976).

- SNV 195'921 ; Testing the antimicrobial effect of textiles and other materials with the help of agar diffusion tests (1976).

Test Procedures

0.05g of the fibres are applied on the top layer of the solidified agar containing the bacteria. For the preparation of the top agar layer, from over-night cultures, a 1 :100 (Staphylococcus aureus) and 1 :1000 (Escherichia coli and Proteus vulgaris) dilution are made and 3.5ml of the dilutions are added to 500ml agar.

Test bacteria: Staphylococcus aureus ATCC 9144

Escherichia coli NCTC 8196 Proteus vulgaris ATCC 6896 Nutrient medium:

Casein soy meal pepton agar ( two layers of agar: 15 ml bottom layer without germs and 5 ml top layer with bacteria)

Incubation: 18-24 hours at 37°C.

Results (Table 2)

Each test is performed twice and both results are given in the table.

Legend; Zl = zone of inhibition in mm

VR = Vinson rating, for growth under the disc

0 = strong growth (no activity)

2 = moderate growth

4 = no growth (good activity)

The Vinson rating is described by L.J. Vinson et al. J.Pharm. Sci. 50, 827-830, 1961

As demonstrated in the microbiological tests, rayon fibres with antimicrobial Triclosan can inhibit the growth of microorganisms on the surface of the fibres (measured by the vinson rating) as well as provide a zone of inhibition around the fibres where the growth of microorganisms is inhibited due to the presence of small amounts of Triclosan which is diffused from the fibres. Example 6: Preparation of anti-fungal formulations

An antifungal substance of formula (15):

is used to prepare a formulation which contains anionic surfactant, nonionic dispersant, small amount of organic solvent and water in the following proportions:

Formulation C1 :

Compound (17) 10%

Anionic surfactant: 30%

Dispersant: 10%

Solvent: 10%

Water: 40%

Compound (15) is also used to prepare a formulation which contains anionic surfactant, nonionic dispersant, small amount of organic solvent, water and a compound of formula (3) in the following proportions:

Formulation D1 :

Compound (15): 10%

Compound (3): 10%

Anionic surfactant: 30%

Dispersant: 10%

Solvent: 10%

Water: 30% Example 7: Preparation of diluted formulation

100 gram of Formulation C1 is added into an appropriate amount of water (deionised) to produce a 800ml formulation. The resulting formulation (Formulation C2) is a stable dispersion in which the concentration of antifungal substance of formula (15) is 50g/litre.

Example 8: Preparation of antimicrobial containing rayon fibres

Cellulose in its' soluble form is prepared by a conventional process. Hence, sized cellulose is treated with caustic soda, oxidising and sulfonating agent and solublilised/pulverised to form aqueous solution followed by filtration and de-gasing. Soluble cellulose prepared as such is ready to be spun to form fibres. Formulation C2 is injected by a diaphragm pump into the main pipeline in which the soluble rayon is being transported to the spinneret for extrusion. The mixture of Formulation B and soluble rayon is further mixed in the pipe to improve homogeneity before it is extruded from the spinneret to form fibres. The pumping speed is adjusted as such that the resulting expected concentration of substance (15) in the fibres is in the range of 0.5 to 1 %.

The so-formed fibre is allowed to pass into an coagulation bath comprised of 10% H₂SO₄ and then a stretching bath comprised of 1% H₂SO₄ in which coagulation and stretching take place followed by desulfonation, washing, oiling and drying.

Example 9: Antimicrobial efficacy of rayon fibres treated with Substance (15)

Purpose

Principle

The treated material (usually as discs) is applied on inoculated agar plates. During the incubation phase, the active substance can diffuse into the agar and inhibit the bacterial growth. Poorly diffusing products should at least be able to inhibit the bacterial growth under the disc. The described agar diffusion test is based on the method AATCC 90-1974. Other methods which are based on diffusion / inhibition principle are:

- SNV 195'921 ; Testing the antifungal effect of textiles and other materials with the help of agar diffusion tests (1976).

Test Procedures

0.05g of the fibres are applied on the top layer of the solidified agar containing the bacteria. For the preparation of the top agar layer, from over-night cultures, a 1 :100 (Staphylococcus Aureus) dilution are made and 3.5ml of the dilutions are added to 500ml agar. In case of Trichophyton Mentagrophytes and Aspergnis Niger, 4ml of spore suspension of the fungi are mixed with 500ml molten agar at 47°C. Such preparations are aimed to achieve an end concentration of the bacteria in the agar at around 10⁴cfu/ml.

Test bacteria: Staphylococcus aureus ATCC 9144

Trichophyton mentagrophytes ATCC 9553 Aspergnis niger ATCC 6275

Nutrient medium: Casein soy meal pepton agar (two layers of agar: 15 ml bottom layer without bacteria and 5 ml top layer with bacteria)

Incubation: 18-24 hours at 37°C for testing activity against bacteria

4 days at 28°C for testing activity against fungi Results (Table 3)

Sample: Rayon staple incorporated with Formulation C2

Each test is performed twice and both results are given in the table.

Legend: VR = Vinson rating, for growth under the disc

0 = strong growth (no activity) 2 = moderate growth

4 = no growth (good activity)

The Vinson rating is described by L.J. Vinson et al. in J.Pharm. Sci. 50, 827-830, 1961

Results indicate that the rayon fibres treated with antifungal substance C1 show good antimicrobial activity against fungi but no activity against bacteria.

Example 10: Preparation of diluted formulation

100 gram of Formulation D1 is added into an appropriate amount of water (deionised) to produce a 800ml formulation. The resulting formulation (Formulation D2) is a stable dispersion in which the concentration of compound (15) as well as compound (3) is 50g/litre. Example 11 : Preparation of antimicrobial containing ravon fibres

Cellulose in its' soluble form is prepared by a conventional process. Hence, sized cellulose is treated with caustic soda, oxidising and sulfonating agent and solublilised/pulverised to form aqueous solution followed by filtration and degasing. Soluble cellulose prepared as such is ready to be spun to form fibres. Formulation D2 is injected by a diaphragm pump into the main pipeline in which the soluble rayon is being transported to the spinneret for extrusion. The mixture of Formulation D2 and soluble rayon is further mixed in the pipe to improve homogeneity before it is extruded from the spinneret to form fibres. The pumping speed is adjusted as such that the resulting expected concentration of substance D2 and Triclosan in the fibres is in the range of 0.5 to 1 %.

The so-formed fibre is allowed to pass into an coagulation bath comprised of 10% H₂SO and then a stretching bath comprised of 1% H₂SO₄ in which coagulation and stretching take place followed by desulfonation, washing, oiling and drying.

Example 12: Antimicrobial efficacy of ravon fibres treated with Compound (15) and Compound (3)

Purpose

Principle

The treated material (usually as discs) is applied on inoculated agar plates. During the incubation phase, the active substance can diffuse into the agar and inhibit the bacterial growth. Poorly diffusing products should at least be able to inhibit the bacterial growth under the disc.

The described agar diffusion test is based on the method AATCC 90-1974. Other methods which are based on diffusion / inhibition principle are: - SNV 195'920; Testing the antibacterial effect of textiles and other materials with the help of agar diffusion tests (1976).

Test Procedures

Test bacteria: Staphylococcus aureus ATCC 9144 Trichophyton mentagrophytes ATCC 9553 Aspergnis niger ATCC 6275

Nutrient medium: Casein soy meal pepton agar ( two layers of agar: 15 ml bottom layer without bacteria and 5 ml top layer with bacteria)

Incubation: 18-24 hours at 37°C for testing activity against bacteria 4 days for testing activity against fungi

Results (Table 4)

Sample: Rayon staple incorporated with Formulation D2

Each test is performed twice and both results are given in the table.

Legend: VR = Vinson rating, for growth under the disc 0 = strong growth (no activity) 2 = moderate growth 4 = no growth (good activity)

The Vinson rating is described by L.J. Vinson et al. J.Pharm. Sci. 50, 827-830, 196

Results indicate that the rayon fibres treated with compound (15) and compound (3) show good antimicrobial activity against both fungi and bacteria.

Claims

1 ) A process for finishing regenerated cellulose fibres with anti-microbial agents, anti-fungal agents or a mixture thereof wherein in the first step, a formulation comprising an antimicrobial agent selected from;

(a) halogeno-o-hydroxydiphenyl compounds;

(b) phenol derivatives;

(c) benzyl alcohols;

(d) chlorohexidine and derivatives thereof;

(e) Ci 2-Cι 4alkylbetaines and Cs-Cι sfatty acid amidoalkylbetaines;

(f) amphoteric surfactants;

(g) trihalocarbanilides;

(h) quaternary and polyquatemary compounds; and (i) thiazole compounds;

and/or an antifungal agent selected from;

- a naphtyl ether derivative

- a benzylimidazol derivative

- a benzoate derivative

and one or more surface active agents is added to the soluble form of the fibres prior to regeneration and in a second step this mixture is extruded from a spinneret into chemical baths to form a regenerated fibre.

2) A process according to claim 1 wherein the antimicrobial agent is a compound of formula

wherein X is oxygen, sulfur or -CH₂-,

Y is chloro or bromo, z is SO₂H, NO₂ or d-C₄-Alkyl, r is 0 to 3,

0 is 0 to 3,

P is O or 1 , m is 0 or 1 and n is O or 1 ; and at least one of r or o is ≠ 0.

3) A process according to claim 1 wherein the antimicrobial agent is a compound of formula

4) A process according to claim 1 wherein the antimicrobial agent is a compound of formula

5) A process according to claim 1 wherein the antifungal agent is a compound of formula

6) A process according to any of claims 1 to 5 wherein the surface active agent is selected from:

acid esters or their salts of alkylene oxide adducts, typically acid esters or their salts of a polyadduct of 4 to 40mol of ethylene oxide with 1 mol of a phenol, or phosphated polyadducts of 6 to 30mol of ethylene oxide with 1mol of 4-nonylphenol, 1 mol of dinonylphenol or, preferably, with 1 mo! of compounds which are prepared by addition of 1 to 3mol of unsubstituted or substituted styrenes to 1 mol of phenol, polystyrene sulfonates, fatty acid taurides, alkylated diphenyl oxide mono- or disulfonates, sulfonates of polycarboxylates, the polyadducts of 1 to 60 mol of ethylene oxide and/or propylene oxide with fatty amines, fatty acids or fatty alcohols, each containing 8 to 22 carbon atoms in the alkyl chain, with alkylphenols containing 4 to 16 carbon atoms in the alkyl chain, or with trihydric to hexahydric alkanols containing 3 to 6 carbon atoms, which polyadducts are converted into an acid ester with an organic dicarboxylic acid or with an inorganic polybasic acid, ligninsulfonates, and, most preferably, formaldehyde condensates such as condensates of ligninsulfonates and/or phenol and formaldehyde, condensates of formaldehyde with aromatic sulfonic acids, typically condensates of ditolyl ether sulfonates and formaldehyde, condensates of naphthalenesulfonic acid and/or naphthol- or naphthylaminesulfonic acids with formaldehyde, condensates of phenolsulfonic acids and/or sulfonated dihydroxydi- phenylsulfone and phenols or cresols with formaldehyde and/or urea, as well as condensates of diphenyl oxide-disulfonic acid derivatives with formaldehyde.

7) A process according to any of claims 1 to 6 wherein the formulation comprising the antimicrobial agent and one or more surface active substances is a solution or an aqueous dispersion.

8) A process according to any of claims 1 to 6 wherein the formulation comprising the antifungal agent and one or more surface active substances is a solution or an aqueous dispersion.

9) A process according to any of claims 1 to 6 wherein concentrated antimicrobial agent in surfactant solution is directly pumped into the cellulose solution just before extrusion.

10) A process according to any of claims 1 to 6 wherein concentrated antifungal agent in surfactant solution is directly pumped into the cellulose solution just before extrusion. 11) A process according to any of claims 1 to 10 wherein the surface-active agent is a nonyl phenyl ether of the formula C₉Hi9C₆H₅O(CH₂CH₂O)₁₀H.

12) A process according to any of claims 1 to 11 wherein the solution comprises two or more surface active agents.

13) A process according to any of claims 1 to 12 wherein the solution or aqueous dispersion contains the antimicrobial agent at a concentration ranging from 1 to 60% based on the total weight of the formulation.

14) A process according to any of claims 1 to 13 wherein in the second step the mixture is passed through the spinneret into chemical baths containing 5% to 15% of concentrated sulfuric acid.

15) A fibre which is obtained by a process as claimed in any of claims 1 to 14.

16) A composition comprising an anti-microbial agent selected from;

(a) halogeno-o-hydroxydiphenyl compounds;

(b) phenol derivatives;

(c) benzyl alcohols;

(d) chlorohexidine and derivatives thereof;

(e) Ci 2-Cι 4alkylbetaines and Cβ-Ci βfatty acid amidoalkylbetaines;

(f) amphoteric surfactants;

(g) trihalocarbanilides;

(h) quaternary and polyquatemary compounds; and (i) thiazole compounds;

and/or an antifungal agent selected from;

- a naphtyl ether derivative

- a benzylimidazol derivative

- a benzoate derivative

and one or more surface active agents selected from; acid esters or their salts of alkylene oxide adducts, typically acid esters or their salts of a polyadduct of 4 to 40mol of ethylene oxide with 1 mol of a phenol, or phosphated polyadducts of 6 to 30mol of ethylene oxide with 1 mol of 4-nonylphenol, 1 mol of dinonylphenol or, preferably, with 1 mol of compounds which are prepared by addition of 1 to 3mol of unsubstituted or substituted styrenes to 1mol of phenol, polystyrene sulfonates, fatty acid tau rides, alkylated diphenyl oxide mono- or disulfonates, sulfonates of polycarboxylates, the polyadducts of 1 to 60 mol of ethylene oxide and/or propylene oxide with fatty amines, fatty acids or fatty alcohols, each containing 8 to 22 carbon atoms in the alkyl chain, with alkylphenols containing 4 to 16 carbon atoms in the alkyl chain, or with trihydric to hexahydric alkanols containing 3 to 6 carbon atoms, which polyadducts are converted into an acid ester with an organic dicarboxylic acid or with an inorganic polybasic acid, ligninsulfonates, and, most preferably, formaldehyde condensates such as condensates of ligninsulfonates and/or phenol and formaldehyde, condensates of formaldehyde with aromatic sulfonic acids, typically condensates of ditolyl ether sulfonates and formaldehyde, condensates of naphthalenesulfonic acid and/or naphthol- or naphthylaminesulfonic acids with formaldehyde, condensates of phenolsulfonic acids and/or suifonated dihydroxydi- phenylsulfone and phenols or cresols with formaldehyde and/or urea, as well as condensates of diphenyl oxide-disulfonic acid derivatives with formaldehyde.

17) A composition according to claim 16 which comprises two or more surfactants, as defined in claim 16.

18) A composition according to any of claims 16 to 17 which is diluted so that the concentration of antimicrobial and/or antifungal is 10g to 100g per litre of the solution.