Diffuser for volatile substances through combustion

Abstract

Diffuser for volatile substances by combustion, comprising a body (1) containing the volatile substances, characterized in that the body is formed from microcapsules (2) containing the volatile substances.

Description

[0001] The present invention relates to a diffuser for volatile substances by combustion, in particular a coil-shaped diffuser for repelling insects, for example mosquitoes, or a diffuser used as an air freshener. Background of the invention

[0002] Mosquito coils used as insecticides have been around for many years. Nevertheless, they are still a widely used product, especially for outdoor applications.

[0003] They typically consist of a mixture of wet-extruded wood particles with the volatile active ingredient, as well as an additive to combat flameless combustion. After the extrusion process, the extruded profile undergoes a forming process and is then dried to produce a solid product.

[0004] The drying process is a very sensitive and critical one. A temperature that is too high during drying can cause some of the active ingredient to evaporate, reducing the future efficiency of the coil. This can also result in economic losses, as the active ingredient is usually considerably more expensive than the other components of the mixture.

[0005] In addition, the final content of the active substance is of great importance, since this value is usually indicated in the health register of biocidal products with a certain permissible tolerance, and a deviation from this tolerance may lead to the withdrawal of the product from the market.

[0006] Therefore, drying usually takes place over a considerably long period of time, closer to days than hours, at a very low temperature of 40-80 °C, to prevent the evaporation of the active ingredients of standard insecticides, which usually have low volatility.

[0007] In recent decades, the insecticide drug industry has attempted to obtain new drug molecules with lower toxicity, greater efficacy, and also higher volatility.

[0008] The current manufacturing process for mosquito coils, which involves wet extrusion followed by drying, is completely inadequate for this new generation of insecticides, as they evaporate significantly at the temperature applied during drying.

[0009] Furthermore, microencapsulation is a well-known process, and its use to reduce the evaporation of highly volatile substances is quite common. A typical example is a microencapsulated fragrance that is mechanically ruptured. This capsule is a membrane that surrounds a droplet of fragrance, preventing its release unless the user breaks it by applying pressure.

[0010] It is typically applied in scratch and sniff labels to allow the user to smell the product before purchase, detergents and fabric softeners, for a lasting effect of the fragrance in the fabric, etc. For these applications, the most commonly used type of microcapsules is based on a melamine membrane.

[0011] This type of capsule could meet the need to prevent the loss of active ingredients during drying, but would hardly withstand the mechanical stress generated during an extrusion process.

[0012] Therefore, an object of the present invention is to provide a diffuser for volatile substances by combustion, wherein the evaporation of the volatile substances during drying in the manufacturing process thereof is reduced or completely avoided. Description of the invention

[0013] The above-mentioned disadvantages are addressed by the diffuser of the invention, which has further advantages which are described below.

[0014] The combustion volatile substance diffuser according to the present invention comprises a body containing the volatile substances, the body being formed of microcapsules containing the volatile substances.

[0015] Advantageously, each microcapsule comprises an outer shell containing the volatile substances therein, and wherein the outer shell may be made of a polymeric material and / or selected from the group consisting of gum arabic, xanthan gum, fatty acids, fatty alcohols, natural waxes and polyethylene.

[0016] Additionally, the outer shell is made of a thermally activated material that melts, expands, or collapses above a predetermined temperature, causing the volatile substances to diffuse into the ambient air. For example, the outer shell is thermally activated at a temperature between 80 °C and 150 °C.

[0017] Preferably, the outer shell contains, along with the active substances, sawdust, combustion-supporting products, antioxidants and / or antifungals, although it may also contain conventional components of this type of diffuser for volatile substances by combustion.

[0018] According to a preferred embodiment, the sawdust has a particle size between 0.1 and 1 mm, the combustion-supporting products are selected from the group comprising sodium nitrate, potassium nitrate and sodium benzoate, and the volatile substances are selected from the group comprising pyrethroids, geraniol and / or citronella.

[0019] According to a preferred embodiment, the body has a coil shape.

[0020] Therefore, in the diffuser of the present invention, such as a mosquito coil, the volatile substances are not added like a liquid but are housed in microcapsules, and the microcapsules reduce or completely avoid the evaporation of the active ingredient during drying. Short description of the characters

[0021] In order to better understand the above, drawings are provided in which a practical embodiment is shown schematically and solely as a non-limiting example. Fig. 1 shows a perspective view of the diffuser of volatile substances by combustion according to an embodiment of the present invention, with the microcapsules shown in a portion thereof. Description of a preferred embodiment

[0022] As in Fig. As shown in Figure 1, the diffuser of volatile substances by combustion according to the present invention comprises a body 1, for example coil-shaped according to the embodiment shown, containing the volatile substances to be diffused into the ambient air, which volatile substances may be insecticidal to repel insects or aromatics to perfume the ambient air.

[0023] According to the present invention, the body 1 is formed from microcapsules 2 containing the volatile substances therein, in particular by means of an outer shell made of polymer.

[0024] For use, the body 1 is burned, which causes the outer shell of the microcapsules 1 to rupture due to the temperature and the volatile substances to diffuse into the ambient air.

[0025] Therefore, the type of microcapsules of interest for the present invention are temperature-activated microcapsules, meaning they rupture when a predetermined temperature is exceeded, rather than those that are mechanically activated or torn by friction, as is the case with conventional microcapsules.

[0026] Activation can be achieved through two different mechanisms: temperature-sensitive release, where the shell materials expand or collapse at a certain critical temperature, and melt-activated release, where the shell material melts due to the increase in temperature.

[0027] The casing materials with such properties may include (but are not limited to) gum arabic, xanthan gum, fatty acids, fatty alcohols, natural waxes, polyethylene, etc.

[0028] Therefore, the polymer shell protects the volatile substances and prevents their evaporation during drying, and cracks or melts when exposed to combustion heat, releasing the volatile substances into the ambient air.

[0029] Although the mechanisms for activating microcapsules are very fast, the temperature increase as the combustion front approaches the microcapsules can be just as fast.

[0030] Consequently, it is critical that the volatile substance is released sufficiently quickly to prevent its chemical integrity from being compromised by temperature.

[0031] Therefore, it is preferred that the thermal activation of the microcapsules falls within the temperature range of 80 °C to 150 °C.

[0032] As for the composition of the contents of the microcapsules, these include: - sawdust with a particle size of 0.1 to 1 mm, - volatile substances in the range of 0.05 to 5% w / w (0.05% when considering highly efficient next-generation pyrethroids), 5% when considering low-performance insecticides such as geraniol or citronella, - combustion-supporting products between 0.2 and 1% by weight (the combustion-supporting products may be sodium nitrate, potassium nitrate, sodium benzoate or any other material commonly used to support combustion), - Antioxidants and - Antifungals.

[0033] Advantageously, the microcapsules are added as a suspension prior to extrusion. The suspension is an aqueous suspension of microcapsules, typically with a maximum microcapsule concentration of approximately 50%.

[0034] As previously explained, for the extrusion of the diffuser body, water is added to the mixture of water and additives. Therefore, when using a suspension, the percentage of microcapsules is approximately equal to the equivalent percentage without the microcapsules, but we eliminate the equivalent of water in the suspension from the amount added.

[0035] Although reference has been made to a specific embodiment of the invention, it is obvious to a person skilled in the art that the diffuser described may be subject to numerous variations and modifications and that all the above details may be replaced by other technically equivalent ones without departing from the scope of protection defined by the appended claims.

Claims

[1] Diffuser for volatile substances by combustion, comprising a body (1) containing the volatile substances, characterized by that the body is formed from microcapsules (2) containing the volatile substances. [2] A combustion volatile substance diffuser according to claim 1, wherein each microcapsule (2) comprises an outer shell containing the volatile substances therein. [3] A combustion volatile diffuser according to claim 2, wherein the outer shell is made of a polymer material. [4] A combustion volatile diffuser according to claim 2, wherein the material of the outer shell is selected from the group consisting of gum arabic, xanthan gum, fatty acids, fatty alcohols, natural waxes and polyethylene. [5] A combustion volatile diffuser according to claim 2, wherein the outer shell is made of a material that melts, expands or collapses above a predetermined temperature. [6] A combustion volatile substance diffuser according to claim 5, wherein the predetermined temperature is between 80°C and 150°C. [7] A combustion volatiles diffuser according to claim 2, wherein the outer shell contains, together with the active substances, sawdust, combustion-supporting products, antioxidants and / or antifungals therein. [8] A combustion volatiles diffuser according to claim 7, wherein the sawdust has a particle size between 0.1 and 1 mm. [9] A combustion volatiles diffuser according to claim 7, wherein the combustion assisting products are selected from the group comprising sodium nitrate, potassium nitrate and sodium benzoate. [10] A combustion volatile substance diffuser according to claim 1, wherein the volatile substances are selected from the group comprising pyrethroids, geraniol and / or citronella. [11] A combustion volatile substance diffuser according to claim 1, wherein the body (1) has a coil shape.

Images