WO2003071871A1

WO2003071871A1 - Substrate, especially textile substrate, and method for producing the same

Info

Publication number: WO2003071871A1
Application number: PCT/EP2003/001927
Authority: WO
Inventors: Heinz Rembold; Christoph Geisler-Kroll
Original assignee: Terra Nostra Produkte Mit Naturextrakten Gmbh
Priority date: 2002-02-26
Filing date: 2003-02-25
Publication date: 2003-09-04
Also published as: DE10208199A1; AU2003210353A1; EP1478230A1

Abstract

The invention relates to a textile substrate and to a method for producing the same. Into said textile substrate (12) microcapsules (4) are introduced which contain a vaporizable active substance. Said active substance diffuses the membrane of the microcapsule (4) and produces a constant active substance concentration on the textile substrate (12). Most preferably, the microcapsules contain a pest-repellent extract from components of the Neem tree.

Description

Carrier, in particular textile carrier, and method for the same

manufacturing

The invention relates to a carrier and a method for its production. Microcapsules, which contain a biologically active, in particular a volatile, substance are fixed on or in the carrier.

Volatile substances, in particular essential oils, such as those used as fragrances, or pest-repellant substances, are usually applied to a carrier by spraying or soaking. The volatile substance evaporates slowly and can develop its effect over a certain period of time. For example, paper strips are soaked with insecticides or at least insect repellant substances and dried. These paper strips can then be placed between items of laundry, for example to protect them from moth damage. However, such paper strips are only suitable for a duration of action of up to a few weeks, since the active substance evaporates comparatively quickly and the insect repellent effect of the paper strip is lost. However, a long-lasting effect is often desired. For example, dust mites and other parasites settle in mattresses, which differ from skin flakes and other organic materials fall off from a person lying on the mattress. This causes large amounts of mite faeces to accumulate in mattresses, which can lead to allergies to house dust. House dust allergy sufferers can therefore show violent reactions after just a short use of a mattress, such as sneezing, swelling of the nasal and ocular mucous membranes or, in extreme cases, asthma attacks.

WO 97/25867 describes an extract from components of the neem tree, which has a very high repellant effect against house dust mites. This extract can be used to equip mattresses, which are then no longer colonized by dust mites. The mattress must be sprayed with the neem extract again at regular intervals in order to maintain the repellant effect and to prevent dust mites from colonizing the mattress. However, the surface-sprayed active ingredient contains oily constituents that spread to the fibers of the outer mattress cover and are also transferred, for example, to a sheet stretched over the mattress. The superficially applied repelling active ingredient is therefore removed from the mattress in the comparatively short time of several months, mainly as a result of the frequently changed bed linen. However, it would be desirable to be able to maintain the excellent activity against a parasite attack over a longer period of time, for example several years.

There is also a need in other areas for a carrier which, for example, releases fragrances over a long period of time. Such a carrier can be used, for example, to furnish furniture or wallpaper in order to produce a pleasant smell in a closed room. It would also be advantageous to permanently protect expensive woolen clothing, such as coats, costumes or suits, from being destroyed by moths. At the same time, antimicrobial treatment would be an advantage.

The object of the invention is therefore to provide a carrier which is as long as possible over a longer period of time evenly releases a certain biologically active, in particular volatile, active ingredient.

The object is achieved with a carrier which is characterized in that microcapsules are provided on the carrier which contain a biologically active ingredient.

The microcapsules form a thin membrane around a tiny drop of a desired active ingredient and completely enclose it. Because of the small layer thickness of the membrane surrounding the microcapsules, the active substances enclosed in the microcapsule can diffuse through the membrane and then evaporate, so that the active substance is evenly released in small amounts over a longer period of time from the microcapsules. The diffusion rate can be controlled via the layer thickness of the membrane and the material of the membrane.

Any biologically active substances can be contained in the microcapsules as long as they can diffuse through the membrane of the microcapsule and have sufficient volatility to subsequently evaporate. A biologically active substance is understood to mean a substance or a mixture of different substances which have an effect of any kind on living beings. This can be a disinfectant effect against microbes, for example. Furthermore, a repellant effect against arthropods such as insects or arachnids can also be achieved. It also includes effects on higher organisms, especially mammals including humans. Such an effect can be, for example, a calming or sleep-promoting effect. It is also particularly advantageous to include oily compounds in the microcapsules that are unsuitable for direct application to the carrier. If the carrier consists of fibers, for example, if it is a textile carrier, the oily compounds can creep along the fiber surface and surround the fiber with an oily film. This can change the appearance of the fiber influence the textile carrier negatively. However, according to the invention, if the oily compound is enclosed in a microcapsule, only very small amounts of the oily compound diffuse through the membrane of the microcapsule. These small amounts of oily compound can then be distributed on the backing by diffusion and produce the desired effect, such as a special fragrance or repellant effect, without large amounts of the oil getting onto the fibers of the textile backing. Furthermore, the inclusion in capsules prevents dust or dirt from being bound by the oily compounds applied to the fibers, which likewise has a disadvantageous effect on the appearance of the wearer. The color of the active substance enclosed in the microcapsules can also be brightened. For example, extracts from plants are often discolored brown, so that they are difficult to apply to light-colored fabrics, especially white fabrics, without causing discoloration of the fabric. Furthermore, the active substance enclosed in the microcapsule is also protected against oxidation by oxygen from the ambient air or against high-energy UV radiation, so that the active substance enclosed in the microcapsule remains longer-lasting and can therefore develop its effect over a longer period of time. To improve the shelf life, the compound enclosed in the microcapsule can also contain an anti-oxidant. Furthermore, volatile compounds can be included in the microcapsules, for example by dissolving them in an oily carrier and enclosing the carrier with the dissolved volatile compound in the microcapsule. The biologically active substances are then released into the environment over a longer period of time. This can, for example, slow down the evaporation of volatile compounds.

The microcapsules provided on carriers can be produced by known processes. An overview of methods for microencapsulation can be found, for example, in Benita, S., Microencapsulation, Vol 73, Marcel Decker 1996 and Risch, SJ, Rei- neccius, GA (Eds.) Flavor encapsulation, Am. Chem. Soc. 1988. Microencapsulation is used, for example, to prepare and preserve flavorings for ready meals or to encapsulate colorants for copy paper. In these applications, however, diffusion of the active ingredient through the membrane of the microcapsule should, if possible, be suppressed. Microcapsules can be produced from various materials, for example from metal oxides, waxes, natural polymers such as alginate, chitosan or cyclodextrins, or also synthetic polymers such as polyvinyl acetate or sulfoxymethyl cellulose. The stability and permeability of the membrane can be varied by adding binders. Microcapsules can be produced with diameters from a few micrometers to several millimeters.

As such, the microcapsules can also be designed so that they are under mechanical stress, e.g. by rubbing, bursting and releasing the enclosed active ingredient. This embodiment is particularly suitable for more volatile active substances which are to be released over a comparatively short period of time, for example several weeks, and which evaporate essentially without residue.

In the case of active substances on an oily basis, or if the active substances themselves are in the form of an oil, and in the event that the active substance is to be released over a longer period, for example several months to several years, the membrane of the microcapsules is preferred in the Formed such that the membrane is permeable to the biologically active ingredient. The biologically active substance can then diffuse through the membrane and is released into the environment in small amounts over a comparatively long period of time.

As already explained above, it should be avoided if possible that the fibers of a textile backing are covered with an oil film, for example. The membrane of the microcapsules is therefore preferably designed such that it has sufficiently high mechanical stability so that the microcapsules do not break open under moderate mechanical stress. Nevertheless, a constant release of the active ingredient to the environment should be ensured by the active ingredient diffusing through the membrane and then evaporating. The membrane is preferably made from an alginate. The production of such microcapsules is described for example in DE 41 25 133 C2.

The microcapsules can be applied to the carrier by various methods. For example, simple sprinkling on the carrier is suitable, taking care to ensure that the microcapsules are distributed as evenly as possible in the carrier. Depending on the type of material of the carrier and the intended use, a simple sprinkling of the microcapsules is sufficient, without the need for further fixation. Coating by brushing, dipping or splashing, by quayander coating, direct coating on the extruder, foam application or fusion is also suitable. A detailed description of these methods can be found e.g. with M. Peter, H.K. Rouette, Basics of Textile Finishing: Handbook of Technology, Processes and Machines, 13th Edition, Deutscher Fachverlag, 1989.

Another method with which the microcapsules can be applied to the carrier is electrostatic flocking, in which the microcapsules are applied to the carrier with the aid of a strong electrostatic field.

The carrier can be designed in any way. The carrier should have sufficient strength to allow the microcapsules to be fixed over long periods of time. Suitable carriers are, for example, textile materials such as woven or non-woven fabrics. However, foams or paper strips are also suitable. Cotton-like carriers are also suitable. The carrier is selected according to the intended use. For example, a non-woven material is suitable as Carrier, if the carrier is inserted as a layer in the structure of a mattress or a piece of clothing. For beds, cotton-like carriers made of synthetic materials are suitable, such as those used for filling pillows or sleeping bags.

The microcapsules are preferably fixed on the carrier. For this purpose, for example, an adhesive can first be applied to the carrier, which can optionally be dissolved in a suitable solvent, and then the microcapsules on the pretreated carrier. In the case of a textile carrier, the adhesive can first be applied to fibers of the textile carrier. It is also possible to first apply the microcapsules to the carrier and only then to apply the adhesive. In order to improve the fixation of the microcapsules on the carrier, it can also be pressed and / or heated for a short time after the microcapsules and the adhesive have been applied. Commercially available powdered, liquid or foamable adhesive systems can be used, e.g. Dispersion adhesive, solvent-based adhesive or reactive adhesive. Fibers, e.g. made of polyolefins or polyvinyl chloride, which change their consistency when exposed to heat.

In a particularly advantageous embodiment, the membrane of the microcapsules consists of a material that softens under the influence of heat and has adhesive properties. Likewise, the microcapsule can also be provided with a coating of a, preferably hot-melt adhesive. After the microcapsules have been placed on the textile carrier, they can then be fixed on the textile carrier under the action of pressure and heat.

As an adhesive, natural or synthetic substances may be used as natural latex, synthetic latex, for example, NBR latex, SBR latex, CR latex, polybutadienes, polyacrylates, Polyes ^¬ ter, polyurethanes, and mixtures of these substances. The carrier is preferably a textile carrier. Any woven or non-woven fiber material per se can be used as the textile carrier. Examples of suitable textile supports are knitted fabrics, woven fabrics, felt, nonwovens, knitwear, composite materials. The fibers of the textile carrier can be vegetable or animal fibers, for example wool. However, synthetic fibers or mixed materials can also be used. A combination with metal mesh, paper, cardboard, foils or spray foils produced by lamination is also possible. According to the invention, microcapsules are then provided on fibers of the carrier which contain an evaporable active substance.

A nonwoven material is particularly preferred as the textile carrier. The fibers of a fleece form a loose, partially or fully consolidated bond, in which the microcapsules can be easily distributed evenly when sprinkled on. After a pressure and heat treatment to fix the microcapsules, the fleece also easily returns to its original shape. The fleece can be cut to any shape, has a low basis weight and, depending on the thickness of the fleece, can also have a good insulating effect. It can therefore be easily incorporated into clothing, for example. Depending on the compounds contained in the microcapsules, the clothing can then exude an individual fragrance or, for example, be permanently protected against pest infestation, in particular moths, by including pest repellant compounds, in particular an extract from components of the neem tree, in the microcapsules.

In order to protect the microcapsules from rubbing off the textile carrier, the textile carrier can be surrounded by a textile shell. The shell can be designed in many different ways. One embodiment is, for example, the items of clothing already described above. A particularly preferred embodiment is a mattress cover, in which the textile carrier, preferably a nonwoven, is surrounded by the underside and the top of fabric webs which are connected to one another. which, for example, are sewn to surround the fleece as a covering. If the microcapsules contain a pest repellant compound, in particular a compound that repels house dust mites, the mattress cover can be used to effectively protect mattresses from mite infestation. This is particularly advantageous for those with allergies to house dust or for mattresses in hotels that are used by a large number of different people and therefore often have a high level of dust mite pollution.

The carrier particularly preferably has a multilayer structure, the microcapsules being sandwiched between two adjacent layers. Such a structure can comprise, for example, two layers of a nonwoven material, the microcapsules being introduced between the two layers. Different materials can also be combined for the individual layers. For example, a fleece made of a synthetic polymer, for example a polyester fleece, can be combined with a wool fleece. It is also possible that only one of the layers consists of a textile material and the other layer, for example of a film, a paper web or a foam. The adjacent layers can be fixed to one another at points or over the entire surface, for example by gluing or sewing. The layers themselves can have any thickness and layers with different or the same thickness can be combined. For example, a spunbonded polyester fleece with a basis weight of 10 g / m ^{2 can be combined} with a 20 cm thick wool fleece.

According to a particularly preferred embodiment, the membrane of the microcapsules consists of a waterproof, heat-resistant material. In this case, the carrier can also be washed, for example in a washing machine. This is particularly advantageous if the carrier is a textile carrier. In general, heat resistance up to about 60 ° C is sufficient, because then the carrier, which is contained in a mattress cover, for example, is washed in the washing machine at regular intervals. machine can be washed with a normal washing program. Such microcapsules have, for example, a membrane made of hardened alginate, for example zinc or calcium alginate, or polyacrylate.

As already described, the microcapsules applied to the carrier are particularly suitable for the inclusion of essential oils, in concentrated form, and also as part of a suitable formulation, for example dissolved in an oil.

According to a particularly preferred embodiment, the microcapsules applied to the carrier, in particular a textile carrier, contain a pest repellent active ingredient, in particular an extract from components of the neem tree. The preparation of a suitable extract is described for example in WO 97/25867. The extract is obtained by extracting the components of the neem tree using supercritical gases, especially supercritical carbon dioxide. The oily extract obtained in this way is almost odorless and has a strong repellant effect, especially against house dust mites.

According to a further preferred embodiment, the biologically active ingredient contained in the microcapsules is a hop extract or a St. John's wort extract. These active substances have a bactericidal effect. As a result, growth of microbes can be suppressed, for example, if the microcapsules are incorporated into a mattress or into bed linen, for example. Another advantage is that such active substances have a calming effect on humans. A deeper and healthier sleep can be achieved, for example, by using a mattress in which microcapsules containing a hop extract are incorporated.

Different active ingredients can also be contained in a microcapsule, as can microcapsules that contain different active ingredients. Contain substances that can be used in combination with each other.

In order to be able to provide a sufficient concentration of active substance in the vicinity of the carrier when the carrier is used for the first time, the carrier preferably has an impregnation which preferably contains the active substance contained in the microcapsules. This impregnation bridges the period of time until a stable concentration of the active ingredient in and around the carrier is established by diffusion of the active ingredient through the membrane of the microcapsules.

The invention also includes a method of making the carrier described above. The carrier according to the invention is produced by first providing a carrier, in particular a textile carrier, onto which microcapsules containing an evaporable active substance are applied, and the microcapsules are fixed on the carrier, for example on fibers of the textile carrier.

In the simplest case, mechanical fixing of the microcapsules in the carrier is sufficient, for example if the carrier has a felt-like structure, and microcapsules are enclosed in cavities formed by the fibers. Such a fixation is sufficient, for example, if the carrier is not later subjected to strong mechanical loads and is processed, for example, into a curtain or a tapestry.

If sufficient fixation is ensured, the microcapsules can be mixed with the carrier by simply sprinkling them on. For example, the carrier can be designed as a pillow or duvet. It is then sufficient to sprinkle the microcapsules into the filling material of the bedding, for example feathers or fibers made of a polymeric material.

However, an adhesive is preferably applied to the textile carrier before and / or after the application of the microcapsules. With the adhesive, the microcapsules can be fixed on the carrier. The adhesive can be applied as a powder that melts when exposed to heat. However, it is also possible to apply the adhesive to the textile backing in solution in a suitable solvent, for example by spraying or scraping.

The microcapsules can also have an adhesive shell. They can then be attached to the carrier, in particular to fibers of the carrier, under the action of pressure and / or with heating.

According to a particularly preferred embodiment of the method according to the invention for producing the carrier described above, a first layer of a carrier is provided. The microcapsules are applied to the first layer of the carrier, then a second layer of a carrier is applied to the first layer of the carrier, it being possible for the first and second layers to be the same or different. The first and second layers are then joined together.

In this embodiment, a sandwich-like structure of the carrier according to the invention is obtained, the microcapsules being fixed between two adjacent layers. The first layer of the carrier can be connected to the second layer of the carrier, for example by gluing or sewing. The materials of the two layers can be the same and, for example, consist of a fleece. However, the two layers can also consist of different materials. For example, the first layer can consist of a paper web and the second layer can consist of a textile material, for example a fabric web. The two layers can then be glued to a wallpaper, for example, the microcapsules being fixed between the paper and the fabric. However, it is also possible to design the first layer of the carrier as a foam sheet and the second layer from a textile material. A composite of foam and textile material can then be integrated into the upholstery of the seat of a chair, for example. Finally, the carrier can also be impregnated, for example impregnated from the active ingredient contained in the microcapsules.

The carrier according to the invention, in particular in an embodiment as a textile carrier, is particularly suitable for incorporation into a mattress, in particular when the microcapsules contain an active ingredient which repels pests, in particular an active ingredient which repels dust mites. The invention therefore also relates to a mattress which comprises at least one layer which consists of the carrier described above. The carrier is preferably designed as a textile carrier, which is preferably designed as a layer running around a mattress core, which is arranged between the mattress core and the mattress outer material. However, it is also possible to provide the textile carrier separately from the mattress core, for example as a mattress cover, in which the carrier described above is incorporated.

The invention is explained in more detail using a preferred embodiment with reference to a drawing. It shows:

1: shows a schematic representation of a device for carrying out the method according to the invention;

Fig. 2: a cross section through a mattress cover.

3: a schematic representation of a cross section through a mattress equipped with a textile carrier according to the invention.

1 shows the production of a textile carrier according to the invention. A carrier web 1, which consists, for example, of a fleece, is fed to an application station 3 via a first deflection roller 2. In the application station 3, adhesive and microcapsules 4 are applied to the carrier web 1 in certain quantities. For this purpose, the order station 3 has corresponding directions for the application, for example a scattering device 3a, through which the microcapsules 4 mixed with a powder adhesive can be sprinkled onto the carrier web 1. The carrier web 1 coated with the microcapsules 4 is led out of the application station 3 and guided into the dryer channel 8 in order to fix the microcapsules 4 on the carrier web 1 by the action of heat, under which the adhesive applied in the application station 3 melts, for example.

If only a simple carrier web 1 is to be produced, the carrier web coated with microcapsules 4 can be led out after the deflection roller 9. The carrier web 1 coated on one side can then be processed into further products.

However, the carrier web 1 coated on one side is preferably further processed into a sandwich structure. For this purpose, a cover sheet 5, which also consists, for example, of a nonwoven, is fed via a third deflection roller 6 to the carrier sheet 1 coated on one side. A pressure roller 10 is arranged opposite the third deflection roller 9. The carrier web 1 and cover web 5 coated on one side with microcapsules 4 are passed between the third deflection roller 9 and the pressure roller 10 and bonded to one another under pressure. A sandwich structure 12 is obtained, in which microcapsules 4 are sandwiched between the carrier web 1 and the top web 5. The sandwich structure can also be impregnated with a starter component. For this purpose, the sandwich structure is carried out under a spray head 11, through which the starter component is sprayed onto the sandwich structure 12. The sandwich structure 12 is then fed via a pair of rollers 9 and 10 for further processing. For shipping or storage purposes, the sandwich structure 12 can be wound up on a roll, for example.

An application of the textile carrier according to the invention is shown in FIG. 2. FIG. 2 shows a section through the structure, for example of a mattress cover, which contains appropriate textile carrier. The mattress cover is covered on the outer sides in each case by a lower and an upper fabric web 13, 14. The textile carrier 12 according to the invention, which has a sandwich structure, is enclosed between the lower and upper fabric webs 13, 14. The textile carrier comprises a carrier web 1 made of a fleece and a cover web 5, which likewise consists of a fleece. Microcapsules 4, which contain a mite-repellant active ingredient, which was obtained by extraction of components of the neem tree, in particular neem cores, are enclosed between carrier web 1 and cover web 5. The textile backing is fixed by stitching 15 between the upper and lower fabric webs 13, 14. The mattress cover shown in FIG. 2 can either be integrated directly into a mattress or can be designed as a cover that can be stretched over the surface of a mattress, for example, by means of a circumferential elastic band. In both embodiments, an infestation of the mattress by dust mites can be effectively suppressed for a period of up to several years.

The equipment of a mattress with the carrier according to the invention is shown schematically in FIG. 3. The mattress core 18, which is designed, for example, as a spring core or made of foam or latex, is covered by a fleece 17. The textile carrier 12 according to the invention described above is worked over the fleece 17 and, as described above, contains a mite-repelling neem extract enclosed in microcapsules. The textile carrier 12 is in turn covered by a mattress fabric 16 and is fixed by this on the mattress core 18. In this embodiment, the textile carrier according to the invention is therefore permanently incorporated in the mattress. This protects both the mattress core 18 and the mat 17 against the ingress of dust mites. In addition, the microcapsules form a protective wall against dust mites that migrate in from outside.

Claims

claims

1. carrier, characterized in that microcapsules are provided on the carrier, which contain a biologically active ingredient.

2. Carrier according to claim 1, characterized in that the carrier has at least two layers which form a common surface, and the microcapsules are provided on or adjacent to the common surface.

3. A carrier according to claim 1 or 2, wherein the microcapsules are attached to the carrier with an adhesive.

4. Carrier according to one of claims 1 to 3, wherein the carrier is a textile carrier.

5. A carrier according to claim 4, wherein the textile carrier is a nonwoven.

6. The carrier of claim 2, wherein the carrier having at least two layers comprises at least a first layer made of a foam and a second layer made of a textile material arranged on the first layer, and the microcapsules are arranged between the first and second layers.

7. Carrier according to one of claims 1 to 6, wherein a sleeve is provided which surrounds the carrier.

8. A carrier according to claim 7, wherein the shell is designed as a fabric.

9. A carrier according to any one of claims 1 to 8, wherein the microcapsules contain an essential oil.

10. A carrier according to any one of claims 1 to 9, wherein the microcapsules contain an extract from components of the neem tree.

11. A carrier according to any one of claims 1 to 10, wherein the microcapsules comprise a membrane which is permeable to the biologically active active ingredient, so that the active ingredient can diffuse through the membrane.

12. The carrier of claim 11, wherein the membrane is constructed from an alginate.

13. Carrier according to one of claims 1 to 12, wherein the carrier has an impregnation.

14. A method for producing a carrier according to any one of claims 1 to 13, wherein a carrier is provided and microcapsules containing an evaporable active ingredient are applied to the carrier, and the microcapsules are fixed on or in the carrier.

15. The method according to claim 14, wherein an adhesive is applied to the textile carrier before and / or after the application of the microcapsules.

16. The method according to claim 14 or 15, wherein the microcapsules have an adhesive shell, and the microcapsules are attached to the fibers of the textile carrier under the action of pressure and / or under heating.

17. The method according to any one of claims 14 to 16, wherein a first layer of a carrier is provided, the microcapsules are applied to the first layer of the carrier, a second layer of a carrier is applied to the first layer of the carrier, the first and second layers can be the same or different, and the first and second layers are connected.

18. The method according to any one of claims 14 to 17, wherein the carrier is impregnated with a starter component.

19. Mattress which contains at least one layer of a carrier according to one of claims 1 to 13.