Bio-based microparticles for textile treatment

Abstract

The invention relates to a method for producing a bio-based particulate emulsion or dispersion for textile treatment and for forming a porous membrane carrying an active substance on said textile at least in some regions, in particular for antibacterial and / or antiviral and / or antiallergic textile treatment, wherein the method comprises the following steps in a given sequence: a) during the formation of an emulsion, mixing a chitosan solution consisting essentially of chitosan in an aqueous lactic acid solution with an emulsion, suspension, dispersion or solution of an active substance in a hydrophobic solvent, b) if desired, separating the active substance from the emulsion, suspension, dispersion or solution, adding additional lactic acid to the emulsion for lowering the pH to a value in the range of 3 to 4.2 and for initiating coagulation of the emulsion, c) adding a cross-linking agent for cross-linking droplets and / or particles in the emulsion or dispersion.

Description

Technical Field

[0001] The invention relates to microparticles for producing active substances for textile treatment, in particular as antiallergic or antiviral or antibacterial active substances. In addition, the invention also relates to corresponding textile articles treated with such microparticles and the use of such microparticles. Background Art

[0002] Bacteria, viruses and allergic threats have become an increasingly serious problem for human and animal health. One way to avoid these problems is to treat the textiles with appropriate textile treatment preparations.

[0003] Finding the optimal textile treatment formulation remains a challenge, since, on the one hand, the corresponding treatment formulation needs to be storage-stable both as a treatment formulation and as a corresponding layer on the textile, while, on the other hand, the active substances contained in the corresponding textile treatment formulation need to be released under appropriate circumstances. On the other hand, the active substances should not be washed off too quickly in repeated washing cycles.

[0004] WO2010142401A1 relates to microcapsules for delivering liquids to surfaces such as hard surfaces or textiles such as mattress fabrics. The microcapsules have a shell comprising an outer surface and an inner surface, the inner surface encapsulating a liquid, and the liquid contains dormant microorganisms such as beneficial microorganisms. The outer surface of the microcapsule may comprise reactive functional groups, whereby the outer surface and the surface may be chemically bonded, for example covalently bonded. By rupturing the capsules deposited on the surface to release the microorganisms onto the surface, the microcapsules provide a beneficial microbial community on the surface. This may reduce or avoid the need for chemical antimicrobial agents to clean the surface. For surfaces that are fabrics or textiles, rupture and release may occur during use of the fabric or textile.

[0005] Sharkawy et al. (Ind. Eng. Chem. Res. 2017, 56, 5516-5526) reported how to give cotton fabrics aromatic and antibacterial properties after microencapsulation using green materials. Limonene and vanillin microcapsules were produced by complex coagulation using chitosan / gum arabic as shell materials and tannic acid as a hardener. The effects of two emulsifiers (Span 85 and polyglycerol polyricinoleate (PGPR)) on encapsulation efficiency (EE%), size and morphology of microcapsules, and cumulative release profiles were studied. The average diameter of the produced microcapsules ranged from 10.4 μm to 39.0 μm, but the EE% was found to be 90.4% to 100%. Regardless of the core material (vanillin or limonene), a single-core morphology was produced using Span 85, while a multi-core structure was produced using PGPR. The obtained microcapsules showed a sustained release pattern; i.e. the total cumulative release of the active agent after 7 days at 37±1°C was 75%, 52% and 19.4% for the multi-core limonene microcapsules, mono-core limonene microcapsules and multi-core vanillin microcapsules, respectively. The grafting of the microcapsules produced on cotton fabric by esterification using citric acid as a non-toxic cross-linking agent followed by thermal fixation and curing was confirmed by SEM and FTIR spectroscopy. Standard antibacterial tests performed on both the individual microcapsules and the microcapsules impregnated on the fabric showed sustained antibacterial activity.

[0006] Valle et al. (Chitosan microcapsules: Methods of the production and use in the textile finishing, J Appl Polym Sci. 2021; 138: e50482) reported that the biopolymer chitosan is considered a promising encapsulant for textile applications due to its biocompatibility, non-toxicity, antimicrobial activity, high availability and low cost. It is the most important organic compound in nature after cellulose. In addition, chitosan has unique chemical properties due to its cationic charge in solution. Microencapsulation technology plays an important role in protecting captured substances and in the persistence of action and controlling the release rate. The application of chitosan microcapsules in textiles follows the current industrial interest in functionalization technologies that give products different properties, such as aromatic finishing, insect repellency, antimicrobial activity and thermal comfort. In this sense, methods for coagulation, ion gelation and LBL for the production of chitosan-based microcapsules are provided, and methods for textile finishing combining them, bath impregnation, filling, dry drying curing, spraying, soaking and grafting chemistry are provided. Finally, current trends in the textile market are identified and guidance for future development is provided. Summary of the invention

[0007] The object of the present invention is to provide new and improved textile treatment preparations which have a particular antibacterial, antiviral and / or antiallergic effect, as well as to provide a process for producing such preparations, and to provide textiles treated with such preparations.

[0008] According to a first aspect of the invention, it relates to a method for producing an emulsion or dispersion for textile treatment and for forming a porous film carrying active substances at least in some areas on the textile, in particular for antibacterial, antiviral and / or antiallergic textile treatment. Typically the droplets and / or particles in the emulsion are microparticles.

[0009] According to a first aspect, the proposed method comprises the following steps in the given order:

[0010] a) mixing a chitosan solution consisting essentially of chitosan in aqueous lactic acid (preferably consisting entirely of chitosan in aqueous lactic acid) with an emulsion, dispersion, suspension or solution of the active substance in a hydrophobic solvent during the formation of the emulsion;

[0011] b) if necessary (not necessary if the emulsion obtained in step a is already at a pH in the range of 3 to 4.2), adding further lactic acid to the emulsion for lowering the pH to a value in the range of 3 to 4.2 and for starting coagulation of the emulsion.

[0012] c) Addition of crosslinking agents for crosslinking the droplets and / or particles in the emulsion or dispersion.

[0013] As will be experimentally demonstrated in the experimental section, the use of chitosan in lactic acid provides unexpected advantages in terms of starting material stability, in terms of odor, color, and antimicrobial activity, especially when compared to the case of chitosan in acetic acid. All of these effects contribute individually or in combination to the inventiveness of the present method relative to the prior art.

[0014] According to a first preferred embodiment of the first aspect of the present invention, the molecular weight of the chitosan in the chitosan solution used in step a) is in the range of 200 g / mol to 500 g / mol, preferably in the range of 200 g / mol to 350 g / mol, most preferably in the range of 250 g / mol to 300 g / mol.

[0015] According to yet another preferred embodiment, the degree of deacetylation of the chitosan in the chitosan solution used in step a) is in the range of 90% to 99%, preferably in the range of 92% to 97%.

[0016] It is generally advantageous if chitosan is present in the chitosan solution in step a) in a concentration in the range 4 to 10% w / w, preferably in the range 5 to 8% w / w, most preferably in the range 4 to 7% w / w.

[0017] Preferably, lactic acid is present in the chitosan solution used in step a) in a concentration ranging from 1.5% to 5% w / w, preferably ranging from 2% to 4.5% w / w, most preferably ranging from 3% to 4% w / w.

[0018] It is further preferred if the pH of the solution used in step a) is in the range from 3 to 5, preferably in the range from 3.5 to 4.2.

[0019] According to another preferred embodiment of the first aspect of the present invention, the viscosity of the chitosan solution used in step a) measured at 25°C is in the range of 1500 cP to 3500 cP, preferably in the range of 2000 cP to 3000 cP.

[0020] As indicated above, the chitosan solution consists essentially of chitosan, water and lactic acid. However, the chitosan solution may contain treatment additives and / or stabilizing additives in a small proportion of less than 0.5% w / w. In line with this, according to a preferred embodiment, the chitosan solution used in step a) also contains at least one stabilizer, preferably in the form of zinc chloride and sodium sulfite or both, in an amount of less than 0.5% w / w, preferably less than 0.3% w / w or less than 0.25% w / w. Preferably, the amount of at least one stabilizer (if present) is at least 0.05% w / w, at least 0.1% w / w or 0.15% w / w.

[0021] Preferably, the chitosan used to prepare the chitosan solution is based on crustacean waste material, however, chitosan derived from non-marine sources may be used as an alternative.

[0022] 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° C. to 30° C., preferably in the range of 18° C. to 25° C. In fact, one of the outstanding advantages of the present invention is that the composition of the chitosan solution and the composition of the emulsion, suspension or solution of the active substance proposed or selected allows the production to be carried out essentially at room temperature.

[0023] Preferably, in step a), before combining the chitosan solution and the active substance, an emulsifier is added, preferably to the chitosan solution, wherein preferably the emulsifier is an emulsifier based on glycerol and / or fatty acids. Preferably, the emulsifier is selected as polyglycerol polyricinoleate (preferably wherein the polyglycerol portion consists of at least 75% weight / weight of diglycerol, triglycerol and tetraglycerol and up to 10% of heptaglycerol or higher glycerol, and / or has a viscosity of 14000 cP and / or has an acid value of a maximum of 3.5 mg KOH / g and a hydroxyl value in the range of 70 mg KOH / g to 110 mg KOH / g, a saponification value in the range of 170 mg KOH / g to 210 mg KOH / g), glyceryl monooleate, glyceryl dicaprylate, glyceryl dimyristate, glyceryl dioleate, glyceryl distearate, glyceryl monomyristate, glyceryl monocaprylate, glyceryl monooleate, glyceryl monostearate, glyceryl stearate, lecithin, polyglyceryl oleate, polyglyceryl stearate, tetraglyceryl monooleate or a combination thereof. The emulsifier is generally added to a concentration in the range of 0.4 to 4% w / w, preferably 0.5 to 3% w / w, further preferably 0.6 to 2.5% w / w, based on the weight of the chitosan solution and the emulsifier.

[0024] According to a preferred embodiment, the active substance is dissolved or suspended in at least one natural oil, preferably selected from 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 made therefrom, or mixtures thereof.

[0025] Preferably, the active substance is present in the natural oil in the system to be added to the chitosan solution in a proportion ranging from 5% to 60% w / w, preferably in a proportion ranging from 10% to 50% w / w.

[0026] Typically, in step a), the chitosan solution is added to the emulsion, suspension or solution of the active substance in the hydrophobic solvent such 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% w / w, preferably in the range of 2% to 9% w / w.

[0027] According to a preferred embodiment, the active substance is selected from microorganisms, essential oils, fragrances, vitamins, prebiotics or combinations thereof.

[0028] The most preferred choice for active substances is to choose them as microorganisms. Usually, these microorganisms are carried in at least one of a carrier and a nutrient, preferably in at least one of calcium carbonate (as a carrier) and a carbohydrate, preferably a prebiotic. Calcium carbonate and / or nutrients (preferably carbohydrates), especially prebiotics, preferably account for at least 90% weight / weight and microorganisms account for up to 10% weight / weight (basically this is the composition of the active substance when added to the corresponding natural oil for preparing 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% of the mass of the microorganisms, most preferably in the range of 10% ± 2% weight / weight.

[0029] Prebiotics are defined in this context as compounds that are non-digestible and resistant to breakdown by gastric acid and enzymes in the human gastrointestinal tract, are fermented by microorganisms on or in the body, and stimulate the growth and activity of beneficial bacteria. Possible nutrients / prebiotics are fructans and galactans, resistant starch, pectin, beta-glucans, and xylo-oligosaccharides, inulin, soy oligosaccharides, pectin-derived oligosaccharides, cocoa-derived flavanols, fructo-oligosaccharides or combinations thereof.

[0030] Preferably, the active substance is a dormant and / or non-pathogenic microorganism, preferably a mixture of different such microorganisms, preferably selected from Bacillus subtilis, Bacillus brevis, Bacillus megaterium, Bacillus licheniformis, Bacillus amyloliquefaciens, Bacillus cereus, Bacillus anthracis, Bacillus licheniformis, Bacillus larvae, Bacillus lentus, Bacillus japonicus, Bacillus sphaericus, Bacillus thuringiensis, Bacillus alvei, Bacillus brevis, Bacillus circulans, Bacillus coagulans, Bacillus macerans or a combination thereof. In addition, prebiotics may be selected from inulin, β-glucan, soy oligosaccharides, pectin and pectin-derived oligosaccharides, cocoa-derived flavanols, oligofructose and added to the formulation.

[0031] The essential oils, fragrances and / or vitamins may be selected from 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 a combination thereof.

[0032] According to yet another preferred embodiment, the diameter of the droplets and / or particles in the emulsion or dispersion obtained in step c) is in the range of 0.2 to 3 microns, preferably in the range of 0.7 to 2.5 microns.

[0033] 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 membrane or shell of cross-linked chitosan. When the corresponding system is applied to a textile, this particle / droplet structure is transformed into a porous membrane of cross-linked chitosan, which adheres to the textile surface without the need for chemical attachment parts and in which porous microparticles of active substances (usually microorganisms) carried in calcium carbonate are embedded.

[0034] Preferably, tannic acid is added as a cross-linking agent in step c), however other cross-linking agents may include humic acid, gallic acid, genipin, sinapinic acid.

[0035] According to a preferred embodiment related to step c), in step c), the cross-linking agent, preferably tannic acid, is added in a proportion ranging from 0.001% to 0.1% weight / weight, preferably ranging from 0.005% to 0.07% weight / weight, relative to the total amount to which the cross-linking agent is added.

[0036] After step c), the porous microparticles or droplets which can be obtained and are usually obtained are formulated, preferably after drying, into a textile treatment system or a concentrate of such a system, wherein preferably, apart from the dispersion obtained in step c), the system is based only on water.

[0037] The textile treatment system may be applied to fibers, yarns, or woven or nonwoven textiles which are preferably further converted into garments, household textiles including furniture textiles.

[0038] The textile treatment system is preferably added in a proportion of 3 to 15 wt % of the fabric, preferably in a proportion of 6 to 10 wt % of the fabric weight.

[0039] According to a second aspect of the invention it relates to a textile treatment system having a porous chitosan matrix with porous particles having active substances embedded therein obtainable or obtained using the method as given above, said textile treatment system preferably being based on an aqueous dispersion, emulsion or solution.

[0040] According to a further aspect of the present invention, it relates to fibers, yarns, or woven or non-woven textiles treated with a textile treatment system as detailed above and preferably obtained using a method as further detailed above, wherein preferably at least in some areas there is a film of porous cross-linked chitosan with porous microparticles of active substances embedded therein.

[0041] According to another aspect of the present invention, it relates to clothing, household textiles including furniture textiles based on fibers, yarns, or woven or non-woven textiles as detailed above, preferably produced using the method as further detailed above.

[0042] Last but not least, and according to yet another aspect of the invention, it 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 fibers, yarns, or woven or non-woven textiles, in particular for the antibacterial and / or antiviral and / or antiallergic treatment of clothing, household textiles including furniture textiles.

[0043] Further embodiments of the invention are set forth in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, which are for the purpose of illustrating the present preferred embodiments of the present invention and not for the purpose of limiting the same. In the accompanying drawings,

[0045] Figure 1 Volume size distributions of two runs of porous chitosan solutions embedded with porous particles are shown;

[0046] Figure 2 SEM images of porous particles in porous chitosan films are shown, showing the films obtained after solid content analysis (the formulation was dried at 105° C. to remove water from the sample);

[0047] Figure 3 SEM images of spores on textiles (microorganisms entrained in chitosan films) and fibers coated via porous chitosan films are shown, wherein a) shows microorganisms embedded in porous chitosan films in polyester knitted fabrics as active substances, b) and c) microorganisms embedded in porous chitosan films in 100% cotton woven fabrics as active substances, d) porous chitosan films coated on 100% polyester knitted fabrics, e) porous chitosan films between fibers on polyester / viscose blended knitted fabrics;

[0048] Figure 4 Comparison of the color stability of chitosan in acetic acid (Ch / AcAc) compared to chitosan in lactic acid (Ch / LacAc) when produced and maintained at room temperature (a)), after storage at 40°C for 30 days (b)), and after 5 days at 60°C (c)). DETAILED DESCRIPTION

[0049] As indicated above, the manufacture of microparticle emulsions or dispersions for textile treatment and for forming a porous film carrying active substances at least in some areas on the textile, in particular for antibacterial, antiviral and / or antiallergic textile treatment, involves the preparation of a chitosan solution. In this chitosan solution in the present experimental part, the concentration of chitosan (in each case weight to weight, weight / weight) is concentration: 6%. The chitosan is a high molecular weight chitosan with a degree of deacetylation of about 95%. In this context, high molecular weight means that the molecular weight of the chitosan is in the range of 250 g / mol to 300 g / mol. The pH of the chitosan solution is usually in the range of 3.7 to 4.0, and the viscosity is in the range of 2000 cP to 3000 cP (measured by the Brookfield method according to ISO 2555 Plastics-Resins in the liquid state or in emulsions or dispersions Determination of apparent viscosity), at a temperature of 25° C., by spindle 63, 20 rpm, Brookfield DVE viscometer. The chitosan solution is a mixture of lactic acid, water and chitosan in the following proportions (weight / weight): chitosan 6%, lactic acid 3.39%, water 90.4%. The remaining amount of zinc chloride and sodium sulfite is added to stabilize the product, usually in an amount of 0.21% weight / weight.

[0050] As also noted above, making a microemulsion or dispersion involves preparing a solution / emulsion / dispersion of the active substance in a natural oil. Typically, the active substance is selected to be a probiotic carried in calcium carbonate and a prebiotic. Typically, in the starting materials used to prepare the active substance system, there is ≥90% weight / weight calcium carbonate carrier and ≤10% Bacillus ferment. Preferably, the probiotic component is a mixture of different species, such as different Bacillus species: Bacillus subtilis, Bacillus pumilus, Bacillus megaterium, Bacillus licheniformis, Bacillus amyloliquefaciens.

[0051] Other Bacillus species may be added, such as Bacillus cereus, Bacillus anthracis, Bacillus licheniformis, Bacillus anthracis, Bacillus larvae, Bacillus lentus, Bacillus japonicus, Bacillus sphaericus, Bacillus thuringiensis, Bacillus alvei, Bacillus brevis, Bacillus circulans, Bacillus coagulans, Bacillus macerans, and the like.

[0052] Prebiotics from the following group of potential nutrients may optionally be added to the formulation: inulin, beta-glucan, soy oligosaccharides, pectin and pectin-derived oligosaccharides, cocoa-derived flavanols, fructooligosaccharides.

[0053] Experimentally, porous particles entrained in porous chitosan membranes are obtained, for example, by a coagulation method. First, at room temperature, a carrier oil is mixed with an active ingredient under gentle stirring to prepare a core solution with an active substance. The active ingredient can be an essential oil, a microorganism, a skin care compound, etc. The active ingredient can be present in a carrier oil at a ratio of 11% to 48% weight / weight. For the biopolymer, i.e., the chitosan phase, a chitosan solution is provided in a container and mixed with polyglycerol polyricinoleate (PGPR). PGPR is derived from the lipid source of castor oil, and the polyglycerol portion is a minimum of 75% diglycerol, triglycerol and tetraglycerol and a maximum of 10% heptaglycerol or higher glycerol, with a viscosity of 14000 cP. In the total mass, the chitosan solution should be 90% to 96%, and the PGPR should be 0.7% to 2% (weight / weight).

[0054] The core solution was added to the biopolymer phase and dispersed using a high performance dispersion instrument (IKA Digital T25) coupled to a dispersion tool (S25N-25G). ) to achieve emulsification. The motor rated input is 800W, and the speed range is 3000rpm to 25000rpm. The dispersing tool is a rotor-stator type and has a stator diameter of 25mm and a rotor diameter of 17mm, capable of producing an emulsion with a final fineness in the range of 1μm to 10μm. For 1kg of product, the speed should be 11000rpm to 12000rpm for 5 minutes. If necessary, the pH of the emulsion is adjusted to 4.0 by adding lactic acid. The emulsion is kept under gentle stirring (250rpm to 300rpm) for 3 hours to ensure that the active ingredient is reticulated in the chitosan film. The cross-linking step is achieved by dripping an aqueous solution of tannic acid (usually 0.35% weight / weight). In the total mass of the product, tannic acid should be in the range of 0.005% to 0.05% (weight / weight). After 3 hours of continuous gentle stirring, the product is collected.

[0055] The final specifications of the product are:

[0056]

[0057] In this formulation, porous particles are entrained in a chitosan matrix. The particles have a diameter of about 1 μm to 2 μm and are sized using a laser diffraction particle size analyzer LS230 from Beckman Coulter based on laser diffraction technology (polarized intensity differential scattering, PIDS method and light scattering theory of Mie and Fraunhofer, see Figure 1) are characterized by volume size distribution. The preparations were dispersed in an aqueous medium (refractive index of 1.33) at room temperature of 20°C. The average diameter was 1.5 μm. SEM images were obtained using a desktop Phenom ProX. The piece of chitosan porous membrane containing particles obtained after the solid content (where water was removed) measurement was placed on a needle previously placed with a carbon tape. SEM images were obtained at a resolution of ×2500 and ×4000 with an intensity of 10 kV. SEM images. Figure 2 Porous particles entrained in a chitosan porous membrane are shown. The porosity of the material was measured in a vacuum chamber by a mercury intrusion instrument from Quantachrome, in which a penetrometer with a sample was filled with mercury. The sample porosity was obtained by infiltrating mercury into the pores via different pressures. The porosity of the raw material (chitosan) was 42%. The porosity of the preparation (chitosan solution containing carrier oil and active ingredient) was about 4%. The reduction in porosity proves that the active substance and the carrier are reticulated in the chitosan membrane, showing good entrainment.

[0058] For non-washable items, an immersion bath containing only water and the formulation can be prepared for treating textiles. The application of the formulation can vary between 6% and 0% of the fabric weight (wof). Drying is carried out under standard conditions (120°C to 130°C). For washable items, an immersion bath containing water, the formulation (5% to 10% wof) and a bio-based polyurethane binder (0.3% to 4% wof) is prepared. A hydrophilic agent (1.5%) can be added to maintain the good feel and hydrophilicity of the fabric. Dry under standard conditions (140°C). The pH of the immersion bath is maintained at about 4.

[0059] The shelf life of conventional preparations is very limited, only a few days or weeks, there is sedimentation and degradation and film formation at the air-liquid interface. Phase separation and sedimentation of gum arabic are particularly observed. Fungal production in the top layer is also observed at room temperature after one week of production.

[0060] In the case of the formulation as proposed here, the product remains stable for several months at room temperature or even at elevated temperature (40° C.) without any adverse effects.

[0061] Furthermore, the microorganisms entrapped in the porous membrane remained viable after 3 months of textile application. Microbial counts on polyester knitted fabric (5.5% wof) showed the following stability of the formulation on the treated textile:

[0062] test CFU / g log After applying 1.66E+06 6.22 After 1 month 4.95E+05 5.69 After 2 months 7.94E+05 5.90 After 3 months 6.32E+05 5.80

[0063] The porous membrane acts as a protective layer for the active ingredient. An example is given by comparing the allergen reduction of samples applied with coated and uncoated microorganisms. The lower porosity of the porous membrane results in high retention and protection of the microorganisms over time, as observed in the table below.

[0064]

[0065] For the proposed formulation, the sour smell is also less noticeable due to the use of lactic acid instead of acetic acid. In addition, the shelf life can be increased by using lactic acid instead of acetic acid. Literature reports that lactic acid has potential antibacterial and antifungal activity. Lactic acid bacteria are also used as natural biopreservatives for food and feed to extend the shelf life of the product. In the method proposed here, the presence of lactic acid mainly dissolves the chitosan, but also helps to achieve a stable formulated product over time, avoiding the growth of fungi. Therefore, lactic acid not only helps in the stability of the chitosan solution, but also helps in the stability of the chitosan porous solution (formulation) embedded with porous particles.

[0066] For SEM analysis of textiles, pieces of textile samples were cut and placed on a needle pre-placed with carbon tape. SEM images were acquired at an intensity of 10 kV in the resolution range of ×1500 to ×7000.

[0067] Figure 3 Figure 1 shows the situation after application of the formulation to the textile fibers. It can be clearly seen that the active substance (in this case, the microorganism) is embedded in the polyester knitted fabric ( Figure 3-1 ) and 100% cotton woven fabrics ( Figure 3-2 and Figure 3-3 ) in the porous chitosan membrane, no mechanical disruption is required to release the microorganisms, and unexpectedly, due to the porosity of the chitosan-based matrix, there is nevertheless a higher stability and availability of the microorganisms. Figures d) and e) show porous chitosan membranes coated on 100% polyester knitted fabric and polyester / viscose blended knitted fabric, respectively. The coating appears between the fibers, and its porous appearance is consistent with the porous membranes observed therein. Figure 2 similar.

[0068] In a further series of experiments, a comparison of a solution of chitosan in acetic acid with a solution of chitosan in lactic acid was performed.

[0069] Storage stability and properties: Chitosan solutions in acetic or lactic acid

[0070] Solutions of 6 wt% chitosan in lactic acid and acetic acid were subjected to different temperatures and different times:

[0071] After 20 days of storage at room temperature (22°C);

[0072] After 20 days of storage at 5°C;

[0073] After 20 days of storage at 40°C;

[0074] After 5 days of storage at 60°C (extreme conditions)

[0075] Viscosity stability

[0076] For chitosan solutions in acetic acid or lactic acid, the viscosity values ​​obtained at different temperatures are:

[0077]

[0078] The viscosity of chitosan in acetic and lactic acid remained very similar to the initial value after 5 and 20 days at room temperature and 5°C. No significant changes were observed.

[0079] For a storage temperature of 40° C., a viscosity reduction was observed after 20 days regardless of the acid type. The viscosity reduction of chitosan solutions in lactic acid (33%) was slightly more pronounced than that of chitosan solutions in acetic acid (6%).

[0080] Different behaviors with respect to viscosity were observed for storage over 5 days at the extreme temperature of 60° C. A decrease in viscosity of the solutions at 60° C. was observed for both chitosan in lactic acid and chitosan in acetic acid. The decrease in viscosity was more pronounced for chitosan in acetic acid, which showed a 55% decrease of the initial value, compared to the viscosity of chitosan in lactic acid, which showed a low 35% decrease of the initial value.

[0081] Smell Difference

[0082] Odor was assessed by qualitative evaluation.

[0083] Chitosan has a strong odor in acetic acid.

[0084] Chitosan has no odor in lactic acid.

[0085] Color stability

[0086] The color of chitosan in acetic acid is more yellow than chitosan in lactic acid.

[0087] The level of color intensity increases with extended storage. After storage at 40°C (30 days) and 60°C (5 days), the yellow color intensifies to nearly brown, see Figure 4 .

[0088] Antibacterial effect data

[0089] A 6% w / w solution of chitosan in acetic acid and a 6% w / w solution of chitosan in lactic acid were applied to a 100% cotton substrate (woven; 118 g / m2).

[0090] Application was done using a laboratory padder (fast; 2.5 rpm; 3 bar) with adjusted pick up. Drying was done in a laboratory tenter (fast; 120°C; 3 minutes).

[0091] The weight percentage of fabric applied with each solution was adjusted to obtain the same applied mass concentration of lactic acid and acetic acid.

[0092] Sample ID illustrate % Fabric Weight Sample 2 Chitosan in acetic acid 7.64 Sample 4 Chitosan in lactic acid 10.70

[0093] Antimicrobial testing was performed using Staphylococcus aureus (ATCC 6538P) according to ASTM E2149 (“Determining the Antimicrobial Activity of Immobilized Antimicrobial Agents Under Dynamic Contact Conditions”).

[0094] The antimicrobial results of the tests are summarized below.

[0095]

[0096] Sample 4 exhibited a strong antibacterial effect, whereas Sample 2 had almost no antibacterial effect.

[0097] Lactic acid clearly showed advantages over the use of acetic acid in achieving antimicrobial activity on fabrics.

[0098] Conclusions for further experiments

[0099] The relative properties of chitosan solutions prepared with acetic or lactic acid are compared as follows:

[0100]

[0101] Explanation of symbols: + = poor...++++ = very good

[0102] stability : The stability of the lactic acid formulation and the acetic acid formulation during storage at room temperature and 40° C. was consistent. Under the extreme condition of 60° C., the viscosity reduction during storage was more pronounced for the formulation using acetic acid (where the viscosity reduction was always more than 50%).

[0103] odor : Lactic acid makes the solution odorless, while acetic acid produces a strong odor.

[0104] color : Lactic acid preparations showed significantly less color than acetic acid.

[0105] Antimicrobial activity: Lactic acid exhibited a strong antibacterial effect, while acetic acid had a low level of effect.

[0106] Therefore, the use of lactic acid to prepare chitosan solutions clearly shows advantages over the use of acetic acid.

Claims

1. A method for producing a microemulsion or dispersion of microparticles for textile treatment and for forming a porous film carrying active substances at least in some areas on the textile, in particular for antibacterial, antiviral and / or antiallergic textile treatment, wherein the method comprises the following steps in a given order: a) mixing a chitosan solution consisting essentially of chitosan in aqueous lactic acid solution with an emulsion, suspension, dispersion or solution of the active substance in a hydrophobic solvent during the formation of the emulsion, b) if necessary, adding further lactic acid to the emulsion for lowering the pH to a value in the range of 3 to 4.2 and for initiating coagulation of the emulsion, c) adding a crosslinking agent for crosslinking the droplets and / or particles in the emulsion or dispersion.

2. The method according to claim 1, wherein the molecular weight of the chitosan in the chitosan solution used in step a) is in the range of 200 g / mol to 500 g / mol, preferably in the range of 200 g / mol to 350 g / mol, most preferably in the range of 250 g / mol to 300 g / mol, and / or wherein the degree of deacetylation of the chitosan in the chitosan solution used in step a) is in the range of 90% to 99%, preferably in the range of 92% to 97%, and / or wherein said chitosan is present in said chitosan solution in step a) at a concentration in the range of 4% to 10% w / w, preferably in the range of 5% to 8% w / w, most preferably in the range of 4% to 7% w / w, and / or wherein lactic acid is present in said chitosan solution used in step a) in a concentration in the range of 1.5% to 5% w / w, preferably in the range of 2% to 4.5% w / w, most preferably in the range of 3% to 4% w / w, and / or wherein 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 wherein the chitosan solution used in step a) has a viscosity measured at 25° C. in the range of 1500 cP to 3500 cP, preferably in the range of 2000 cP to 3000 cP, and / or wherein the chitosan solution used in step a) further comprises a stabilizer, preferably in the form of at least one of zinc chloride and sodium sulfite, in an amount of less than 0.5% w / w, preferably less than 0.3% w / w or less than 0.25% w / w, And / or wherein the chitosan is based on crustacean waste material.

3. The method according to any one of the preceding claims, wherein at least one of steps a) to c), preferably all steps a) to c) are carried out at a temperature in the range of 15°C to 30°C, preferably in the range of 18°C ​​to 25°C.

4. The method according to any one of the preceding claims, wherein in step a), before combining the chitosan solution and the active substance, an emulsifier is added, preferably to the chitosan solution, wherein preferably the emulsifier is an emulsifier based on glycerol and fatty acids, preferably selected from polyglycerol polyricinoleate, glycerol monooleate, glycerol dicaprylate, glycerol dimyristate, glycerol dioleate, glycerol distearate, glycerol monomyristate, glycerol monocaprylate, glycerol monooleate, glycerol monostearate, glycerol stearate, lecithin, polyglycerol oleate, polyglycerol stearate, tetraglycerol monooleate or a combination thereof, preferably in a concentration ranging from 0.4% to 4% w / w, preferably from 0.5% to 3% w / w, further preferably from 0.6% to 2.5% w / w, based on the weight of the chitosan solution and the emulsifier.

5. The method according to any one of the preceding claims, wherein the active substance is dissolved or suspended in at least one natural oil, preferably selected from 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 made therefrom, or combinations thereof, Preferably the active substance is present in the natural oil in a proportion ranging from 5% to 60% w / w, preferably from 10% to 50% w / w.

6. A method according to any one of the preceding claims, wherein in step a), the chitosan solution is added to the emulsion, suspension, dispersion or solution of the active substance in a hydrophobic solvent such that in the combined emulsion the emulsion, suspension, dispersion or solution of the active substance in a hydrophobic solvent is present in a proportion ranging from 1% to 12% w / w, preferably in the range of 2% to 9% w / w.

7. The method according to any one of the preceding claims, wherein the active substance is selected from microorganisms, essential oils, fragrances, vitamins, prebiotics or combinations thereof, wherein in the case of microorganisms, these are carried in at least one of a carrier and nutrients, preferably in at least one of calcium carbonate and carbohydrates, in particular prebiotics, wherein the calcium carbonate and / or carbohydrates, in particular prebiotics, represent at least 90% w / w and the microorganisms represent at most 10% w / w, wherein preferably the active substance is a dormant and / or non-pathogenic microorganism, preferably a mixture of different such microorganisms, preferably such microorganisms are selected from Bacillus subtilis, Bacillus brevis, Bacillus megaterium, Bacillus licheniformis, Bacillus amyloliquefaciens, Bacillus cereus, Bacillus anthracis, Bacillus licheniformis, Bacillus larvae, Bacillus lentis, Bacillus japonicus, Bacillus sphaericus, Bacillus thuringiensis, Bacillus alvei, Bacillus brevis, Bacillus circulans, Bacillus coagulans, Bacillus macerans or a combination thereof, and the prebiotics may be optionally selected from fructans and galactans, inulin, β-glucan, soy oligosaccharides, pectin and pectin-derived oligosaccharides, cocoa-derived flavanols, oligofructose and added to the preparation, And / or wherein the essential oils and / or vitamins are selected from 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 a combination thereof.

8. The method according to any one of the preceding claims, wherein the diameter of the droplets and / or particles in the emulsion or dispersion obtained in step c) is in the range of 0.2 to 3 microns, preferably in the range of 0.7 to 2.5 microns, and / or wherein said droplets and / or particles in said emulsion or dispersion obtained in step c) consist of porous microparticles of said active substance embedded in a porous membrane of cross-linked chitosan.

9. The method according to any one of the preceding claims, wherein in step c), as a cross-linking agent is added a cross-linking agent selected from tannic acid, humic acid, gallic acid, genipin, sinapinic acid or a combination thereof, and / or wherein in step c), the cross-linking agent, preferably tannic acid, is added in a proportion ranging from 0.001% to 0.1% w / w, preferably ranging from 0.005% to 0.07% w / w, relative to the total amount to which the cross-linking agent is added.

10. The method according to any one of the preceding claims, wherein after step c), the porous microparticles obtained are formulated, preferably after drying, into a textile treatment system or a concentrate of such a system, wherein preferably, apart from the dispersion obtained in step c), the system is based only on water.

11. A method according to the preceding claims, wherein the textile treatment system is applied to fibers, yarns, or woven or non-woven textiles, which are preferably further converted into clothing, household textiles including furniture textiles, wherein the textile treatment system is preferably added in a proportion of 3% to 15% by weight of the fabric, preferably in a proportion of 6% to 10% by weight of the fabric.

12. A textile treatment system obtainable or obtained using a method according to the preceding claim 11, said textile treatment system preferably being based on an aqueous dispersion, emulsion or solution.

13. A fiber, a yarn, or a woven or nonwoven textile treated with a textile treatment system according to the preceding claim, wherein preferably at least in some areas a porous chitosan membrane is present with porous microparticles of the active substance embedded therein.

14. A garment, household textile including furniture textile based on a fiber, a yarn, or a woven or nonwoven textile according to the preceding claims.

15. Use of porous microparticles obtained according to the method of any one of the preceding claims 1 to 11 for the antibacterial and / or antiviral and / or antiallergic treatment of fibers, yarns, or woven or non-woven textiles, in particular for the antibacterial and / or antiviral and / or antiallergic treatment of clothing, household textiles including furniture textiles.

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