Bio-based microparticles for textile treatment

Abstract

1. A method for producing an emulsion or dispersion of bio-based microparticles for fabric treatment and for forming on at least some areas on the fabric a porous coating carrying an active substance, in particular for antibacterial and / or antiviral and / or antiallergic fabric treatment, comprising the following steps in the given order: a) mixing a chitosan solution consisting essentially of chitosan in aqueous lactic acid with an emulsion, suspension, dispersion or solution of an active substance in a hydrophobic solvent to form an emulsion; b) optionally adding further lactic acid to the emulsion to reduce the pH to a value in the range of 3 to 4.2 to initiate coacervation of the emulsion; c) adding a crosslinking agent to crosslink the droplets and / or particles in the emulsion or dispersion.

Description

[Technical field]

[0001] The present invention relates to a method for producing microparticles for treating fabrics, comprising active substances, in particular antiallergic, antiviral or antibacterial substances. The present invention further relates to corresponding fabric articles treated with such microparticles and to the use of such microparticles. [Background technology]

[0002] Bacteria, viruses and even allergy threats are becoming more and more serious problems for human and animal health. One of the ways to avoid these problems is the treatment of fabrics with corresponding fabric treatment formulations.

[0003] Finding an optimal fabric treatment formulation remains challenging, since the corresponding treatment formulation must be storage stable not only as a treatment formulation but also as a corresponding layer on the fabric, on the one hand, the active substances contained in the corresponding fabric treatment formulation must be released under suitable conditions, on the other hand, the active substances must not be washed off too quickly in repeated washing cycles.

[0004] US Patent No. 5,999,333 relates to microcapsules for delivering liquids to surfaces such as hard surfaces and fabrics such as mattress ticking. The microcapsules comprise a shell having an outer surface and an inner surface, the inner surface encapsulating a liquid, the liquid containing microorganisms, such as beneficial microorganisms, in a dormant state. The outer surface of the microcapsules can include reactive functional groups, which allow the outer surface to chemically bond, for example covalently bond, with the surface. The microcapsules provide beneficial microflora to the surface by rupturing the capsules deposited on the surface and releasing the microorganisms onto the surface. This can reduce or eliminate the need for chemical antimicrobial agents to clean the surface. If the surface is a fabric or textile, the rupture and release can occur during use of the fabric or textile.

[0005] Sharkawy et al. (Non-Patent Document 1) reported a method for imparting fragrance and antibacterial properties to cotton fabrics by microencapsulation using environmentally friendly materials. Limonene and vanillin microcapsules were produced by complex coacervation using chitosan / gum arabic as shell material and tannic acid as hardener. The effect of two emulsifiers, namely Span 85 and polyglycerol polyricinoleate (PGPR), on the encapsulation efficiency (EE%), size and morphology of microcapsules, and cumulative release profile was studied. The average diameter of the produced microcapsules was found to be in the range of 10.4-39.0 μm, while the EE% was found to be 90.4%-100%. Regardless of the core material (vanillin or limonene), the use of Span 85 resulted in mononuclear structures, whereas the use of PGPR resulted in polynuclear structures. The obtained microcapsules showed a sustained release pattern, i.e., the cumulative release of the active ingredient after 7 days at 37±1°C was 75% for polynuclear limonene microcapsules, 52% for mononuclear limonene microcapsules, and 19.4% for polynuclear vanillin microcapsules. Grafting of the produced microcapsules onto cotton fabric via esterification reaction using citric acid as a non-toxic crosslinker, followed by heat fixing and curing, was confirmed by SEM and FTIR spectroscopy. Standard antibacterial assays performed on both the microcapsules alone and after fabric impregnation showed sustained antibacterial activity.

[0006] Valle et al. (Non-Patent Document 2) report that the biopolymer chitosan is considered as a promising encapsulation agent for textile applications due to its biocompatibility, non-toxicity, antimicrobial activity, high availability and low cost. After cellulose, chitosan is the most important organic compound in nature. Chitosan also has unique chemical properties due to its cationic charge in solution. Microencapsulation technology plays an important role in protecting the encapsulated substances, prolonging their effectiveness and controlling the release rate. The application of chitosan microcapsules to textiles is in line with the current industry interest in functionalization techniques to impart various properties to products, such as aroma finish, insect repellency, antimicrobial activity and thermal comfort. In this sense, coacervation, ionic gelation and LBL methods are presented for the production of chitosan-based microcapsules, incorporating bath exhaustion, filling, dry curing, spraying, immersion and grafting chemicals as textile finishing methods. Finally, current trends in the textile market are identified and guidelines for future developments are provided. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2010142401 [Non-patent literature]

[0008] [Non-Patent Document 1] Ind. Eng. Chem. Res. 2017, 56, 5516-5526 [Non-Patent Document 2] Chitosan microcapsules: Methods of the production and use in the textile finishing, J Appl Polym Sci.2021;138:e50482 Summary of the Invention

[0009] It is an object of the present invention to provide new and improved fabric treatment formulations having, inter alia, antibacterial, antiviral and / or antiallergic effects, as well as methods for producing such formulations and fabrics treated with such formulations.

[0010] According to a first aspect of the invention, the invention relates to a method for producing a fabric treatment emulsion or dispersion and for forming on said fabric at least a portion of the fabric a porous coating carrying an active substance, in particular an antibacterial, antiviral and / or antiallergic fabric treatment. Typically the droplets and / or particles in the emulsion are microparticles.

[0011] According to a first aspect, the proposed method comprises the following steps: a) mixing a chitosan solution consisting essentially of chitosan in aqueous lactic acid (preferably consisting only of chitosan in aqueous lactic acid) with an emulsion, dispersion, suspension or solution of an active agent in a hydrophobic solvent to form an emulsion; b) optionally (not necessary if the emulsion obtained in step a is already in the pH range of 3 to 4.2) adding further lactic acid to the emulsion to lower the pH to a value in the range of 3 to 4.2 and initiate coacervation of the emulsion; c) adding a cross-linking agent to cross-link the droplets and / or particles in the emulsion or dispersion; in the given order.

[0012] As experimentally demonstrated in the experimental section, the use of chitosan in lactic acid provides unexpected advantages in terms of starting material stability, odor, color and antimicrobial activity, especially when compared to the situation with chitosan in acetic acid, all of which, individually or in combination, contribute to the advancement of the present method over the prior art.

[0013] According to a first preferred embodiment of the first aspect of the present invention, the chitosan in the chitosan solution used in step a) has a molecular weight in the range of 200-500 g / mol, preferably in the range of 200-350 g / mol, most preferably in the range of 250-300 g / mol.

[0014] According to yet another preferred embodiment, the chitosan in the chitosan solution used in step a) has a degree of deacetylation in the range of 90-99%, preferably in the range of 92-97%.

[0015] It is usually advantageous if chitosan is present in the chitosan solution of step a) in a concentration in the range of 4 to 10% by weight, preferably in the range of 5 to 8% by weight, most preferably in the range of 4 to 7% by weight.

[0016] Preferably, lactic acid is present in the chitosan solution used in step a) at a concentration in the range of 1.5-5 wt.%, preferably in the range of 2-4.5 wt.%, most preferably in the range of 3-4 wt.%.

[0017] It is further preferred if the pH of the solution used in step a) is in the range of 3 to 5, preferably in the range of 3.5 to 4.2.

[0018] According to yet another preferred embodiment of the first aspect of the present invention, the chitosan solution used in step a) has a viscosity, measured at 25°C, in the range of 1500-3500 cP, preferably in the range of 2000-3000 cP.

[0019] As mentioned above, the chitosan solution consists essentially of chitosan, water and lactic acid. However, the chitosan solution may contain a small proportion of processing additives and / or stabilizing additives, less than 0.5% by weight. Accordingly, according to a preferred embodiment, the chitosan solution used in step a) further comprises at least one stabilizer, preferably in the form of zinc chloride and / or sodium sulfite, in an amount less than 0.5% by weight, preferably less than 0.3% by weight or less than 0.25% by weight. Preferably, when at least one stabilizer is present, it is present in an amount of at least 0.05% by weight, at least 0.1% by weight or 0.15% by weight.

[0020] Preferably, the chitosan used in preparing the chitosan solution is based on shellfish waste, although chitosan from non-marine sources may alternatively be used.

[0021] Preferably, at least one of steps a) to c), preferably all steps a) to c), is carried out at a temperature in the range of 15 to 30° C., preferably in the range of 18 to 25° C. Indeed, it is one of the outstanding advantages of the present invention that the proposed composition of the emulsion, suspension or solution of chitosan solution and active or selected substance allows the preparation to be carried out essentially at room temperature.

[0022] Preferably, an emulsifier is added to the chitosan solution prior to combining the chitosan solution and the active substance in step a), preferably the emulsifier is a glycerol and / or fatty acid based emulsifier. Preferably, the emulsifier is selected as polyglycerol polyricinoleate (preferably, the polyglycerol portion is composed of at least 75% by weight of di-, tri- and tetraglycerols and at most 10% by weight of heptaglycerol or higher, and / or has a viscosity of 14000 cP, and / or has an acid value of up to 3.5 mg KOH / g, a hydroxyl value in the range of 70 to 110 mg KOH / g, and a saponification value in the range of 170 to 210 mg KOH / g), glycerol monooleate, glyceryl dicaprylate, glyceryl dimyristate, glyceryl dioleate, glyceryl distearate, glyceryl monomyristate, glyceryl monooctanoate, glyceryl monooleate, glyceryl monostearate, glyceryl stearate, lecithin, polyglyceryl oleate, polyglyceryl stearate, tetraglyceryl monooleate, or a combination thereof. Usually, the emulsifier is added to a concentration in the range of 0.4 to 4% by weight, preferably 0.5 to 3% by weight, and more preferably 0.6 to 2.5% by weight, based on the weight of the chitosan solution and emulsifier.

[0023] According to a preferred embodiment, the active substance is dissolved or suspended in at least one natural oil, which is preferably selected from the group consisting of oat oil, castor oil, coconut oil, almond oil, cod liver oil, fish oil, cottonseed oil, rapeseed oil, soybean oil, linseed oil, palm oil, wheat germ oil, rice bran oil, olive oil, avocado oil, argan oil, blueberry seed oil, carrot seed oil, hazelnut oil, jojoba oil, quinoa oil, sesame oil, walnut oil, algae oil, acai oil, shea butter, mango butter, cocoa butter or hydrogenated oils thereof or combinations thereof.

[0024] Preferably, the active substance is present in the natural oil in the system added to the chitosan solution in a proportion ranging from 5 to 60% by weight, preferably 10 to 50% by weight.

[0025] Typically, in step a), the chitosan solution is added to the emulsion, suspension or solution of the active substance in the hydrophobic solvent so that in the combined emulsion, the emulsion, suspension, dispersion or solution of the active substance in the hydrophobic solvent is present in a proportion ranging from 1 to 12% by weight, preferably from 2 to 9% by weight.

[0026] According to a preferred embodiment, the active substance is selected from the group consisting of microorganisms, essential oils, fragrances, vitamins, prebiotics or combinations thereof.

[0027] Most preferred as active substances is the selection of active substances as microorganisms. Usually these microorganisms are supported on at least one of carriers and nutrients, preferably calcium carbonate (as carriers) and carbohydrates, preferably prebiotics. Calcium carbonate and / or nutrients (preferably carbohydrates), especially prebiotics, preferably make up at least 90% by weight, and microorganisms up to 10% by weight (basically this is the composition of the active substances when added to the corresponding natural oil to prepare the system to be added to the chitosan solution). The mass proportion of nutrients (preferably in the form of prebiotics) is preferably in the range of 5% to 20% by weight of the microorganisms, most preferably in the range of 10% by weight ±2% by weight.

[0028] Prebiotics in this context are defined as compounds that survive digestion in the human gastrointestinal tract, survive degradation by gastric acid and enzymes, are fermented by microorganisms on or in the body, and promote the growth and activity of beneficial bacteria. Possible nutrients / prebiotics are fructans and galactans, resistant starches, pectins, beta-glucans, xylooligosaccharides, inulin, soybean oligosaccharides, pectin-derived oligosaccharides, cocoa-derived flavanols, fructooligosaccharides, or combinations thereof.

[0029] Preferably, the active agent is a dormant and / or non-pathogenic microorganism, preferably a mixture of various such microorganisms, preferably selected from the group consisting of: Subtilis, Pumilus, Megaterium, Licheniformis, Amyloliquefaciens, Cereus, Anthracis, Licheniformis, Larbe, Lentimolbus, Popilia, Sphaericus, Thuringiensis, Alvei, Brevis, Circulans, Coagulans, Macerans or combinations thereof. Prebiotics may also be added to the formulation, selected from the group of inulin, beta-glucan, soybean oligosaccharides, pectin and pectin-derived oligosaccharides, cocoa-derived flavanols, fructooligosaccharides.

[0030] The essential oils, fragrances and / or vitamins may be selected from the group of bergamot oil, lavender oil, peppermint oil, cedarwood oil, citronella oil, cardamom oil, cinnamon bark oil, clove oil, eucalyptus oil, geranium oil, ginger oil, lemon myrtle oil, lemongrass oil, rosemary oil, sandalwood oil, spearmint oil, tea tree oil, thyme oil, rose oil, orange oil, grapefruit oil, chamomile oil, wintergreen oil, vitamin A, vitamin B3, vitamin B5, vitamin C, vitamin D, vitamin E, vitamin K, or combinations thereof.

[0031] According to yet another preferred embodiment, the droplets and / or particles in the emulsion or dispersion obtained in step c) have a diameter in the range of 0.2 to 3 micrometers, preferably in the range of 0.7 to 2.5 micrometers.

[0032] The droplets and / or particles in the emulsion or dispersion obtained in step c) preferably consist of porous microparticles of active substances embedded in a porous film or shell of crosslinked chitosan. When the corresponding system is applied to a fabric, this particle / droplet structure is transformed into a porous film of crosslinked chitosan, which adheres to the fabric surface without the need for chemical binding sites, and in which porous microparticles of active substances, usually microorganisms supported on calcium carbonate, are embedded.

[0033] Preferably, tannic acid is added as a cross-linking agent in step c), but other cross-linking agents include humic acid, gallic acid, genipin, sinapic acid, etc.

[0034] According to a preferred embodiment of step c), in step c), a crosslinking agent, preferably tannic acid, is added in a proportion in the range of 0.001 to 0.1% by weight, preferably 0.005 to 0.07% by weight, based on the total amount of the crosslinking agent to be added.

[0035] After step c), the resulting porous microparticles or droplets are typically formulated, preferably after drying, to form a fabric treatment system or a concentrate of such a system, preferably which system is based solely on water apart from the dispersion obtained in step c).

[0036] The fabric treatment system can be applied to fibers, yarns, or woven or nonwoven fabrics, which are preferably further processed into apparel, household fabrics, such as upholstery fabrics.

[0037] Preferably, the fabric treatment system is added at a rate of 3-15% by weight of the fabric, preferably at a rate of 6-10% by weight of the fabric.

[0038] According to a second aspect of the invention, the invention relates to a fabric treatment system, preferably based on an aqueous dispersion, emulsion or solution, obtainable or obtained using the method described above, comprising a porous chitosan matrix, in which porous particles of an active substance are embedded.

[0039] According to yet another aspect of the invention, the invention relates to fibres, yarns or woven or nonwoven fabrics treated with the fabric treatment system as detailed above and preferably obtained using the method as further detailed above, wherein a coating of porous crosslinked chitosan in which porous microparticles of an active substance are embedded is preferably present in at least some areas.

[0040] According to a further aspect of the invention, the invention relates to clothing, household textiles, such as furniture textiles, based on the fibres, yarns or woven or nonwoven textiles produced using the process as detailed above, preferably as further detailed above.

[0041] Finally, according to another further aspect, the present invention relates to the use of porous microparticles or droplets obtained using the method detailed above for the antibacterial and / or antiviral and / or antiallergic treatment of fibres, yarns or woven or nonwoven fabrics, in particular for clothing, household fabrics, such as furniture fabrics.

[0042] Further embodiments of the invention are defined in the dependent claims.

[0043] Preferred embodiments of the present invention will now be described with reference to the drawings, which are intended to illustrate the currently preferred embodiments of the present invention and are not intended to limit the same. [Brief description of the drawings]

[0044] [Figure 1] FIG. 1 shows the volumetric size distribution of porous chitosan solutions with embedded porous particles for two runs. [Diagram 2] FIG. 1 shows an SEM image of porous particles in a porous chitosan film, showing the film obtained after solids analysis (removal of water from the sample by drying the formulation at 105° C.). [Diagram 3] Figure 1 shows SEM images of spores (microorganisms encapsulated in chitosan film) on fabrics and fibers coated with porous chitosan film, a) shows microorganisms as active substances embedded in porous chitosan film on polyester knitted fabric, b) and c) show microorganisms as active substances embedded in porous chitosan film on 100% cotton woven fabric, d) shows porous chitosan film coated on 100% polyester knitted fabric, and e) shows porous chitosan film between fibers of polyester / viscose blend knitted fabric. [Figure 4] FIG. 1 shows a comparison of color stability of chitosan in acetic acid (Ch / AcAc) with that in lactic acid (Ch / LacAc) when prepared and stored at room temperature (a), after 30 days of storage at 40° C. (b), and after 5 days of storage at 60° C. (c). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] As pointed out above, the production of emulsions or dispersions of microparticles for fabric treatment, the formation of a porous coating on at least some areas of said fabric, carrying active substances, in particular for antibacterial, antiviral and / or antiallergic fabric treatment, involves the preparation of a chitosan solution. In the chitosan solutions of this experimental section, the concentration of chitosan is in each case 6% by weight w / w. The chitosan is a high molecular weight chitosan with a degree of deacetylation of about 95%. High molecular weight in this context means that the molecular weight of the chitosan is in the range of 250-300 g / mol. The pH of the chitosan solution is usually in the range of 3.7-4.0 and the viscosity is in the range of 2000-3000 cP at 25° C. in a Brookfield DVE viscometer at spindle 63, 20 rpm (ISO 2555 Plastics-Resins in the Liquid State or in Emulsions or Dispersions - Determination of Apparent Viscosity by the Brookfield Method). The chitosan solution is a mixture of lactic acid, water and chitosan in the following proportions (w / w): 6% chitosan, 3.39% lactic acid, 90.4% water. To stabilize the product, the balance of zinc chloride and sodium sulfite is added, usually in an amount of 0.21% by weight.

[0046] As also pointed out above, the preparation of emulsions or dispersions of microparticles includes the preparation of solutions / emulsions / dispersions of active substances in natural oils. Typically, the active substances are selected to be probiotics supported on calcium carbonate and prebiotics. Typically, the starting materials used to prepare the active system contain 90% or more by weight of calcium carbonate carrier and 10% or less by weight of Bacillus ferment. Preferably, the probiotic component is a mixture of different genera and species, such as a mixture of different genera and species of Bacillus, Subtilis, Pumilus, Megaterium, Licheniformis, and Amyloliquefaciens.

[0047] Other Bacillus species such as Bacillus cereus, Bacillus anthracis, Bacillus licheniformis, Bacillus anthracis, Bacillus larbei, Bacillus lentimolbus, Bacillus popiliae, Bacillus sphaericus, Bacillus thuringiensis, Bacillus alvei, Bacillus brevis, Bacillus circulans, Bacillus coagulans, Bacillus macerans, etc. may also be added.

[0048] Prebiotics can optionally be added to the formulation from the following group of possible nutrients: inulin, beta glucan, soy oligosaccharides, pectin and pectin-derived oligosaccharides, cocoa-derived flavanols, fructooligosaccharides.

[0049] Experimentally, porous particles encapsulated in a porous chitosan film are obtained, for example, by the coacervation method. First, a carrier oil and an active ingredient are mixed with moderate stirring to prepare a core solution containing the active substance at room temperature. The active ingredient can be an essential oil, a microorganism, a skin care compound, etc. The active ingredient can be present in the carrier oil in a proportion of 11% to 48% by weight. A chitosan solution is provided as a biopolymer in a carrier, i.e., a chitosan phase, which is mixed with polyglycerol polyricinoleate (PGPR). PGPR is obtained from a lipid source of castor oil, and the polyglycerol portion is a minimum of 75% di-, tri-, and tetraglycerol, a maximum of 10% heptaglycerol or higher, and has a viscosity of 14000 cP. In the total mass, the chitosan solution should be 90-96% and the PGPR 0.7-2% (w / w).

[0050] The core solution is added to the biopolymer phase and emulsification is carried out using an IKA high-performance dispersing device T25 digital ULTRA-TURRAX® equipped with a dispersing tool S25N-25G. The motor rated power is 800 W and the speed range is 3000-25000 rpm. The dispersing tool is of the rotor-stator type, with a stator diameter of 25 mm and a rotor diameter of 17 mm, allowing the production of extremely fine emulsions in the range of 1-10 μm. For 1 kg of product, the speed should be 11000-12000 rpm for 5 minutes. The pH of the emulsion is adjusted to 4.0 by adding lactic acid if necessary. The emulsion is maintained under moderate stirring (250-300 rpm) for 3 hours to ensure the networking of the active ingredient into the chitosan film. The crosslinking step is achieved by adding an aqueous solution of tannic acid (usually 0.35% by weight) in small portions. Tannic acid should be in the range of 0.005-0.05% (w / w) of the total mass of the product. After 3 hours of continuous moderate stirring, the product is collected.

[0051] The final product specifications are as follows:

[0052] [Table 1]

[0053] In this formulation, porous particles are embedded in the chitosan matrix. The particles have a diameter of about 1-2 μm and are characterized by volume size distribution using a Beckman Coulter LS230 laser diffraction particle sizer based on laser diffraction techniques (Polarized Intensity Difference Scattering, PIDS method and Mie and Fraunhofer light scattering theory, see Figure 1). The formulation is dispersed in a medium of water (refractive index 1.33) at room temperature of 20°C. The average diameter is 1.5 μm. SEM images are obtained using a Phenom ProX desktop. The piece of chitosan porous film containing the particles obtained after solid content measurement (water removal) was placed on the pin where the carbon tape was previously placed. SEM images were obtained at 10 kV and resolutions of x2500 and x4000. Figure 2 shows the porous microparticles encapsulated in the chitosan porous film. The porosity of the material was measured with a Quantachrome Poremaster, where the penetrometer containing the sample is filled with mercury in a vacuum chamber. The porosity of the sample is achieved by penetrating the pores with mercury at different pressures. The porosity of the raw material (chitosan) is 42%. The porosity of the formulation (chitosan solution with carrier oil and active ingredient) is about 4%. The reduction in porosity proves the reticulation of the active substance and carrier into the chitosan film, which indicates good encapsulation.

[0054] For non-washable articles, an impregnation bath containing only water and the formulation can be prepared for the treatment of the fabric. The dosage of the formulation is variable from 6 to 10% of the fabric weight (wof). Drying is carried out under standard conditions (120-130°C). For washable articles, an impregnation bath containing water, the formulation (5-10% wof) and a bio-based polyurethane binder (0.3-4% wof) is prepared. To maintain good hand and hydrophilicity of the fabric, a hydrophilicity imparting agent (1.5% wof) can be added. Drying is carried out under standard conditions (140°C). The pH of the impregnation bath is maintained at about 4.

[0055] Conventional formulations have a very limited shelf life of only a few days or weeks, and suffer from precipitation, degradation, and film formation at the air-liquid interface. In particular, phase separation and precipitation of gum arabic have been observed. Also, fungal formation has been observed in the top layer at room temperature one week after preparation.

[0056] The formulation presented here allows the product to be stable for several months without any adverse effects at room temperature or even at elevated temperatures (40° C.).

[0057] Furthermore, the microorganisms encapsulated in the porous film maintained viability even after 3 months of application to the fabric. The microbial counts on polyester knit fabric (5.5% wof) demonstrated the stability of the formulations on the treated fabric as follows:

[0058] [Table 2]

[0059] The porous membrane acts as a protective layer for the active ingredient. An example is a comparison of allergen reduction for samples with coated and uncoated microorganisms. As can be seen in the table below, the lower the porosity of the porous membrane, the higher the retention and protection of the microorganisms over time.

[0060] [Table 3]

[0061] In the proposed formulation, lactic acid is used instead of acetic acid, and therefore the acidic odor is less noticeable. Furthermore, the use of lactic acid instead of acetic acid can extend the shelf life. It has been reported in the literature that lactic acid may have antibacterial and antifungal properties. Lactic acid bacteria have also been used as natural biological preservatives in food and feed to extend the shelf life of the product. In the approach proposed herein, the presence of lactic acid is primarily aimed at dissolving chitosan, but also helps to prevent fungal growth and achieve a stable formulated product over time. Thus, lactic acid helps to stabilize not only the chitosan solution, but also the chitosan porous solution (formulation) in which the porous particles are embedded.

[0062] For SEM analysis of the fabrics, cut out pieces of fabric samples and place them on the pins where the carbon tape was previously placed. Obtain SEM images at an intensity of 10 kV and within the resolution range ×1500–×7000.

[0063] Figure 3 shows the situation after application of the formulation to the textile fibres. A porous chitosan coating embedded with active substances (in this case microorganisms) is clearly visible on the polyester knitted fabric (Figure 3-1) and on the 100% cotton woven fabric (Figures 3-2 and 3-3), without the need for mechanical disruption to release the microorganisms, and surprisingly, with a higher stability and availability of the microorganisms than would be expected given the porosity of the chitosan-based matrix. Figures d) and e) show the porous chitosan coating coated on the 100% polyester knitted fabric and on the polyester / viscose blend knitted fabric, respectively. The coating is applied between the fibres, and its porous appearance is similar to that of Figure 2, where a porous coating is visible.

[0064] In a further set of experiments, a comparison was made between chitosan in acetic acid and chitosan in lactic acid.

[0065] Storage stability and properties: Chitosan in acetic acid or chitosan in lactic acid 6% by weight chitosan solutions in lactic and acetic acid were exposed to different temperatures for different times: After 20 days of storage at room temperature (22°C); After 20 days of storage at 5°C; After 20 days of storage at 40°C; After 5 days of storage at 60°C (extreme conditions).

[0066] viscosity stability Viscosity values ​​obtained at different temperatures for chitosan in acetic acid or chitosan in lactic acid solutions:

[0067] [Table 4]

[0068] After 5 and 20 days at room temperature and at 5° C., the viscosity of chitosan in acetic and lactic acids remains very similar to the initial value. No significant changes were observed.

[0069] After 20 days at a storage temperature of 40°C, a decrease in viscosity is observed regardless of the type of acid, the decrease being somewhat more pronounced for chitosan in lactic acid (33%) than for chitosan in acetic acid (6%).

[0070] Different viscosity behaviors are observed when stored at the extreme temperature of 60°C for 5 days. A decrease in the viscosity of the solutions at 60°C is observed for both chitosan in lactic acid and chitosan in acetic acid. The decrease in viscosity of chitosan in acetic acid is more pronounced compared to that of chitosan in lactic acid, showing a decrease of 55% of the initial value, whereas the decrease in viscosity of chitosan in lactic acid is less pronounced, showing a decrease of 35% of the initial value.

[0071] Differences in smell The odor was evaluated by qualitative assessment.

[0072] The odor of chitosan in acetic acid is strong.

[0073] Chitosan in lactic acid is odorless.

[0074] color stability Chitosan in acetic acid is more yellow in color than chitosan in lactic acid.

[0075] The level of colour intensity increases with increasing storage time: after storage at 40°C (30 days) and 60°C (5 days) the yellow colour intensified to almost brown (see Figure 4).

[0076] Antibacterial effect data A 6% by weight solution of chitosan in acetic acid and a 6% by weight solution of chitosan in lactic acid were applied to a 100% cotton substrate (woven fabric; 118 g / m 2 ) was administered.

[0077] Application was performed using a lab padder (high speed; 2.5 rpm; 3 bar) with adjusted pick-up. Drying was performed on a lab stenter (high speed; 120° C.; 3 min).

[0078] The application percentage of each solution relative to fabric weight was adjusted so that the application mass concentrations of lactic acid and acetic acid were the same.

[0079] [Table 5]

[0080] Antibacterial testing was performed using Staphylococcus aureus (ATCC 6538P) in accordance with ASTM E2149 ("Determination of antibacterial activity of immobilized antibacterial agents under dynamic contact conditions").

[0081] The antibacterial results of the test are summarized below.

[0082] [Table 6]

[0083] Sample 4 shows a strong antibacterial effect, while Sample 2 shows almost no antibacterial effect.

[0084] Lactic acid shows clear advantages in achieving antimicrobial activity in fabrics compared to the use of acetic acid.

[0085] Conclusions regarding further experiments The relative properties of chitosan solutions prepared with either acetic or lactic acid are compared below.

[0086] [Table 7]

[0087] stability The stability of the lactic and acetic acid preparations is constant during storage at room temperature and at 40° C. Under the extreme conditions of 60° C., the decrease in viscosity during storage is much more pronounced for the preparation with acetic acid, the decrease in viscosity always exceeding 50%.

[0088] odor : Lactic acid forms an odorless solution, but acetic acid has a strong odor.

[0089] color The lactic acid preparation is significantly less colored than the acetic acid preparation.

[0090] Antibacterial activity : Lactic acid has a strong antibacterial effect, while acetic acid has a lower level of effectiveness.

[0091] Thus, the preparation of chitosan solutions using lactic acid shows clear advantages over the use of acetic acid.

Claims

1. A method for producing an emulsion or dispersion of microparticles for fabric treatment, and for forming a porous film on at least a portion of the fabric surface that carries an active substance for fabric treatment, particularly antibacterial, antiviral and / or anti-allergic, the method comprising the following steps: a) A step of forming an emulsion by mixing a chitosan solution consisting substantially of chitosan in aqueous lactic acid with an emulsion, dispersion, suspension, or solution of the active substance in a hydrophobic solvent. b) If necessary, add lactic acid to the emulsion to lower the pH to a value in the range of 3 to 4.2 and initiate coacervation of the emulsion. c) A step of adding a crosslinking agent to crosslink droplets and / or particles in the emulsion or dispersion. A method that includes in a given order.

2. The chitosan in the chitosan solution used in step a) has a molecular weight in the range of 200 to 500 g / mol, preferably in the range of 200 to 350 g / mol, most preferably in the range of 250 to 300 g / mol. and / or, the chitosan in the chitosan solution used in step a) has a degree of deacetylation in the range of 90 to 99%, preferably in the range of 92 to 97%, and / or, the chitosan is present in the chitosan solution of step a) at a concentration in the range of 4 to 10% by weight, preferably in the range of 5 to 8% by weight, most preferably in the range of 4 to 7% by weight. and / or, lactic acid is present in the chitosan solution used in step a) at a concentration in the range of 1.5 to 5% by weight, preferably in the range of 2 to 4.5% by weight, most preferably in the range of 3 to 4% by weight. and / or, the pH of the solution used in step a) is in the range of 3 to 5, preferably in the range of 3.5 to 4.

2. and / or, the chitosan solution used in step a) has a viscosity in the range of 1500 to 3500 cP, preferably in the range of 2000 to 3000 cP, as measured at 25°C. and / or, the chitosan solution used in step a) further contains a stabilizer, preferably in the form of at least one of zinc chloride and sodium sulfite, in an amount of less than 0.5% by weight, preferably less than 0.3% by weight or less than 0.25% by weight, and / or, the chitosan is based on crustacean waste materials, The method according to claim 1.

3. The method according to claim 1, wherein at least one of steps a) to c), preferably all of steps a) to c), is carried out at a temperature in the range of 15 to 30°C, preferably in the range of 18 to 25°C.

4. The method according to claim 1, wherein in step a), an emulsifier is preferably added to the chitosan solution before combining the chitosan solution and the active substance, and preferably the emulsifier is a glycerol and fatty acid-based emulsifier, preferably selected from polyglycerol polyricinoleate, glycerol monooleate, glyceryl dicaprylate, glyceryl dimyristate, glyceryl dioleate, glyceryl distearate, glyceryl monomyristate, glyceryl monooctanoate, glyceryl monooleate, glyceryl monostearate, glyceryl stearate, lecithin, polyglyceryl oleate, polyglyceryl stearate, tetraglyceryl monooleate, or a combination thereof, and the emulsifier is added at a concentration preferably in the range of 0.4 to 4% by weight, preferably in the range of 0.5 to 3% by weight, and more preferably in the range of 0.6 to 2.5% by weight, relative to the weight of the chitosan solution and the emulsifier.

5. The active substance is dissolved or suspended in at least one natural oil, the natural oil being preferably selected from the group consisting of oat oil, castor oil, coconut oil, almond oil, cod liver oil, fish oil, cottonseed oil, rapeseed oil, soybean oil, linseed oil, palm oil, wheat germ oil, rice bran oil, olive oil, avocado oil, argan oil, blueberry seed oil, carrot seed oil, hazelnut oil, jojoba oil, quinoa oil, sesame oil, walnut oil, algae oil, acai oil, shea butter, mango butter, cocoa butter or hydrogenated oils thereof, or combinations thereof. Preferably, the active substance is present in the natural oil in a proportion of 5 to 60% by weight, preferably 10 to 50% by weight, according to claim 1.

6. The method according to claim 1, wherein in step a), the chitosan solution is added to the emulsion, suspension, dispersion, or solution of the active substance in a hydrophobic solvent so that in the combined emulsion, the emulsion, suspension, dispersion, or solution of the active substance in the hydrophobic solvent is present in a proportion of 1 to 12% by weight, preferably 2 to 9% by weight.

7. The active substance is selected from the group consisting of microorganisms, essential oils, fragrances, vitamins, prebiotics, or combinations thereof, and in the case of microorganisms, the microorganism is supported on at least one of a carrier and nutrients, preferably at least one of calcium carbonate and carbohydrates, particularly prebiotics, wherein the calcium carbonate and / or carbohydrates, particularly prebiotics, account for at least 90% by weight, and the microorganism accounts for up to 10% by weight. Preferably, the active substance is a dormant and / or non-pathogenic microorganism, preferably a mixture of such various microorganisms, the microorganisms are preferably selected from the group consisting of Subtilis, Pumyrus, Megatherium, Likeniformis, Amyloricephaciens, Cereus, Anthracis, Likeniformis, Larbe, Lentimorphus, Popilie, Sphericus, Thuringensis, Albei, Brevis, Circulans, Coagulans, Macerans, or combinations thereof, and prebiotics may optionally be added to the formulation, selected from the group consisting of fructan and galactan, inulin, β-glucan, soy oligosaccharides, pectin and pectin-derived oligosaccharides, cocoa-derived flavanols, and fructooligosaccharides. And / or, the essential oils and / or vitamins are selected from the group consisting of bergamot oil, lavender oil, peppermint oil, cedarwood oil, citronella oil, cardamom oil, cinnamon bark oil, clove oil, eucalyptus oil, geranium oil, ginger oil, lemon myrtle oil, lemongrass oil, rosemary oil, sandalwood oil, spearmint oil, tea tree oil, thyme oil, rose oil, orange oil, grapefruit oil, chamomile oil, wintergreen oil, vitamin A, vitamin B3, vitamin B5, vitamin C, vitamin D, vitamin E, vitamin K, or combinations thereof. The method according to claim 1.

8. The droplets and / or particles in the emulsion or dispersion obtained in step c) have a diameter in the range of 0.2 to 3 micrometers, preferably in the range of 0.7 to 2.5 micrometers. and / or, the droplets and / or particles in the emulsion or dispersion obtained in step c) consist of porous microparticles of the active substance embedded in a porous film of crosslinked chitosan. The method according to claim 1.

9. In step c), a crosslinking agent selected from the group consisting of tannic acid, humic acid, gallic acid, genipin, sinapic acid, or a combination thereof is added. and / or, in step c), a crosslinking agent, preferably tannic acid, is added in a proportion of 0.001 to 0.1% by weight, preferably 0.005 to 0.07% by weight, relative to the entire area to which the crosslinking agent is added. The method according to claim 1.

10. The method according to claim 1, wherein, after step c), the obtained porous microparticles are preferably blended after drying to produce a fabric treatment system or a concentrate of such system, and preferably the system is based only on water in addition to the dispersion obtained in step c).

11. The method according to claim 10, wherein the fabric treatment system is applied to fibers, yarns, or woven or nonwoven fabrics, the fibers, yarns, or woven or nonwoven fabrics are further processed into household fabrics, preferably including fabrics for clothing and furniture, and the fabric treatment system is added in a proportion of 3 to 15% of the fabric weight, preferably 6 to 10% of the fabric weight.

12. A fabric treatment system that can be obtained or obtained using the method described in claim 11, preferably based on an aqueous dispersion, aqueous emulsion, or aqueous solution.

13. A fiber, yarn, or woven or nonwoven fabric treated with the fabric treatment system described in claim 12, wherein a porous chitosan coating in which porous microparticles of the active substance are embedded is preferably present in at least a portion of the area.

14. Household fabrics, including clothing and furniture fabrics, based on the fibers, yarns, or woven or nonwoven fabrics described in claim 13.

15. Use of porous microparticles obtained by the method described in claim 1 for antibacterial and / or antiviral and / or anti-allergic treatment of fibers, yarns, or woven or nonwoven fabrics, particularly for household fabrics including clothing and furniture fabrics.

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