WO2005110589A1

WO2005110589A1 - A process for coating dried granulated powders a detergent product and a softener

Info

Publication number: WO2005110589A1
Application number: PCT/BR2004/000188
Authority: WO
Inventors: Henry Charles Favre
Original assignee: Bentonit União Nordeste Sa
Priority date: 2004-05-17
Filing date: 2004-10-01
Publication date: 2005-11-24
Also published as: AR045852A1; BRPI0401766A

Abstract

The present invention relates to a process for coating dried granulated powders, which comprises applying a coating composition onto them. This process imparts improved visual effect and physical properties to the powder. The dried granulated powder is especially suitable for manufacturing detergents, soaps toilet, soaps and softeners.

Description

Title. "A PROCESS FOR COATING DRIED GRANULATED POWDERS, A DETERGENT PRODUCT AND A SOFTENER" The present invention relates to a process of coating dried granulated powders (DGP), which comprises applying a coating composition onto them. The thus obtained granules are especially suitable for producing detergents, soaps, toilet soaps and softeners. The invention further relates to a detergent product and a softener that comprise granules obtained according to said process. Description of the Prior Art By DGP it is understood the pure bentonites and its combinations any other clayey minerals, inorganic fillers, inorganic and organic salts, which may be in combination with each other on the order of from 0 to 95% by weight, as long as the result of these compositions is self-granulating or granu- lable by means of agglomerating aids. Bentonites are clayey minerals containing 75% or more of a mineral known as montmorilonite. More specifically, bentonites are hydrated hexagonal phylosilicates of aluminum and magnesium. Their generic chemical composition is Si₈.AI( _-x).O₂o-(OH) .nH₂O (Na, Mg, Ca)_x. Bentonites are especially known for exhibiting a high absorbing power and a high swelling index, swelling up to 25 times its initial volume when in the presence of water. Bentonites are widely employed in the manufacture of cleaning products such as detergents, soaps and toilet soaps, cosmetics, paints and varnishes, sanitary granulates, ceramics, among others. Especially for the case of the cleaning products mentioned before, bentonite imparts an attractive visual aspect, such as coloration and/or brightness effect to the detergent composition, softening the textile fiber onto which they are applied, and also acts as a detergent-tablet disintegrating a- gent. It is known that the brightness effect on granulated powders can be obtained by means of a coating process that comprises applying a coating composition containing a pearlizing agent onto said granulated powders. This process is commonly known as pearlizing process. The pearlization takes advantage of absorptive capacity of the granulated powder in absorbing the vehicle of the coating composition, keeping on its surface only the pigmented pearlizer and optionally other ingredients, such as a paint fixer. Therefore, what is called anchorage of the coating composition on the substrate surface occurs. Additionally, the pearlization enables the inclusion of liquids and/or solids in the granulated powder. Various types of substrate are usually subjected to pearlizing processes, such as metallic surfaces, plastic surfaces, particulate material (powders, granules, grains, flakes), seeds, dragees, bul- lets, among others. The coating composition virtually forms a "cover" on the substrate. In the case of a particulated material, pearlization is advantageously applied for rendering difficult to the formation of agglomerates, contributing to the reduction of losses of fines during subsequent processing of the substra- te, imparting greater fluidity and rendering difficult to the volatilization of thermosensitive ingredients. It is further interesting for the substrate to be in the tone close to the desired pearlizing effect for reduction of cost and better revelation. BR 9816110 is directed to a process for preparing a granular de- tergent composition, which comprises coating detergent granules with an inorganic aqueous solution. The inorganic aqueous solution containing, optionally, brighteners, perfume, enzymes, among others, is applied by vaporization onto the surface of the granules at a temperature preferably in the range of from about 30°C to about 70°C. The subsequent incorporation of perfume into the detergent granule is made by additional vaporization onto the coated granule. It may become necessary to add a peel coating in order to prevent agglomeration of granules. BR 0011797 describes a process for coating detergent granules, which comprises coating the granule with a water-soluble coating material in a fluidized bed. The coating material may be selected from anionic surfactants, silicates, hydrophobic material, and non-hydrating inorganic materials. The material for coating may also include auxiliary ingredients such as brigh- tening agents. The detergent granules are coated by a fluid paste of detergent materials, which is sprayed in downward direction in a stream of gas flowing downwards to dry said granules. In this process, a free-flowing dried material is produced. BR 8700243 describes a process for coating a powdered detergent by pearlization, which comprises an active detergent agent, a sequestering agent, a particle-forming agent and optional components such as perfume. These components are mixed in a mixer together with a carbohydrate pearlizing agent and an active agent, at a temperature of about 70 - 80°C, causing the carbohydrate to swell. Subsequent drying of this material is carried out by aspersion. The thus obtained pearlizing coating is due to the occurrence of gelatinization of the carbohydrate that impregnates and involves the detergent particles. Additionally, the surface-treating processes (BUN process) and processes used for coating dragees, bullets and seeds are known, which, besides requiring simultaneous or subsequent drying, do not impart a satisfactory brightening effect or reproductibility of tones and specific mixtures. These coating processes, however, have drawbacks with regard to operational conditions and steps, equipment necessary to carry them out and final properties of the coated substrate. There is a need for high temperature ranges, flow of substrate to be coated and carrier fluid of a coating composition in countercurrent, steps of drying the granules during and/or after the coating, additional step for incorporating perfume. Therefore, there remains the need for a process of coating gra- nulated powder that operates under milder conditions, with simpler processing and, consequently, a reduced manufacture cost, and further to impart good physical properties. In this regard, the applicant has developed a process for coating dried granulated powders (DGP), wherein the coating composition comprises components that impart improved physical properties to the coated granulated powder. In addition, the process is carried out under conditions of ambient temperature and pressure and with a reduced number of process steps. No existing technique provides all the advantages and benefits of the present invention.

Objectives of the Invention An objective of the present invention is to provide dried granula- ted powders having improved resistance to wear and visual effect, high power of incorporating active ingredients, and easy dispersion in the final product. These easy-to-disperse granulated powders are especially intended for the manufacture of detergent compositions. It has been found that this objective is achieved by means of a coating process that comprises applying a coating composition, optionally comprising a pearlizing agent and/or a volatile and/or thermosensitive component onto granulated powders that have been dried until a 0.0% to 15.0% moisture content has been reached. The present process additionally enables excellent dyeing revelation with a low concentration of coating agent, and can be carried out with a reduced number of process steps, under conditions of ambient temperature and pressure. Another object of the present invention is to provide detergent and softening products that comprise granules obtained according to said process. Brief Description of the Invention The above objectives are achieved by means of a process for coating DGP that comprises the steps of drying granulated powder until a moisture content of 0.0% to 15.0% ; preparing a coating composition; weighing a predetermined amount of the coating composition; leading the coa- ting composition in the amount predetermined by the weighing to a mixer by means of a carrier; and applying the coating composition onto the dried granulated powders. The present invention also describes granulated powders coated by the above-described process, especially for use in softeners and deter- gent products, including powdered and liquid detergents, toilet soaps and other soaps either in bar or liquid. Detailed Description of the Invention The present invention describes a process for coating granulated powders comprising the following steps:

(i) drying powder granules until a moisture content of about 15%; (ii) preparing a coating composition;

(iii) weighing a predetermined amount of a coating composition;

(iv) leading the coating composition in the amount predetermined by weighing to a mixer through a carrier fluid; and (v) applying the coating composition onto the dried powder. The drying of the DGP has the objective of imparting such moisture contents that agglomeration of the granules will be prevented, and so as to favor the incorporation of actives into the granulated powders during the process of coating them. It is desirable for the moisture to be in the range from about 0.00% to 15% by weight. The coating composition preferably applied to the DGP comprises: about 3% to about 25% of a coating agent; about 0.1 % to about 1 % of a dyeing component; about 50% to about 90% of an active ingredient; - about 0.1 % to about 2% of a fixing agent; about 10% to about 20% of a solvent. Optionally, additives may be added to the composition to impart additional properties. The coating composition has the function, in the context of the present invention, of incorporating active ingredients, especially thermosensi- tive and volatile ones, imparting an improved visual effect, preferably by means of a pearlizing coating, and improving resistance to wear in DGP. The coating agent accounts for increasing resistance to wear and/or for imparting an improved visual effect to the final product. By prefe- rence, the coating agent is an insoluble white filler that may be selected from talc, titanium oxide, magnesium oxide and others. When a pearlized effect is desired, mica supported on titanium oxide may be added. Preferably, the present invention employs mica supported on titanium oxide. The dying component may be pigments, dyes or a combination thereof, and they are basically intended to impart dyeing to the DGP's. The pigments may be organic or inorganic, synthetic or natural pigments. Examples thereof are: iron oxides, titanium oxide, zinc sulfide, zirconium oxide, chromium oxide. The dyes may be selected from acidic and alkaline ones. The active ingredient may be a liquid or solid substance. It has the function of improving the physical properties of the coated DGP. In the present invention, the following actives are preferably employed: optical bri- ghteners, buffers, aloe vera, perfumes, glycerin, silicone, plasticizer, enzymes, surfactants, chelants, co-builders, germicides, fungicides, antioxidants, stabilizers, emollients, fragrances, foam inhibitors, anticorrosives, emulsifiers, opacifiers, pH adjuster, or a combination thereof. Particularly, the perfumes may be either synthetic or natural. The preferred examples are: aldehydes, ketones, esters, essences and natural extracts such as extract of rose, lavender, lemon or orange oil and the like. The fixing agent has the function of preventing migration of the colored component in the granule, which might eventually lead to undesirable effects of fading or formation of stains, and further of imparting greater resistance to wear of the granule. Preferred fixing agents are those that are extremely soluble and may be selected from carboxymethyl cellulose, xanthan gum, PVA emulsions and resins, or combinations thereof, more preferably carboxy methyl cellulose. Water is preferably used as a solvent. However, any other solvents that has affinity to the fillers, pigments and dyes employed can be used The coating composition may be in the form of a suspension, solution, emulsion or dispersion. Preferably, the coating of the DGP is carried out from an aqueous suspension of the above-defined composition. A process for preparing an aqueous suspension of the coating composition basically comprises adding its components, either simultaneously or successively, to a mixing tank provided with a mechanical stirrer, which are maintained under stirring until homogenization is reached. The coating process of the present invention is carried out after granulation, drying and sorting of the DGP, thus representing a finishing step in the production of DGP. The DGP are preferably fed in a mixer or any vessel maintained in movement, which promotes renewal of the surface without causing shearing, but sufficient to enable incorporation of the coating composition into the DGP. By preference, a dragee-making device or a rotary homogenizer is u- sed. Alternatively, a rotary drum may be sued. The coating composition is transferred from the stirred tank in which is has been prepared to a weighing device, such as a regulator balance, for weighing a predetermined amount. Subsequently, the composition is led to a mixer with the help of a flow of air or carrier gas, preferably compressed air. The coating composition is preferably atomized by means of a compressed-air sprayer onto the DGP. The atomization is made onto the granules under constant homogenization. Alternatively, the incorporation may be carried out by means of a pumping system that pumps it to a nozzle t- hrough which the coating composition is finally atomized. As an additional alternative, the DGP may be dipped into a coating composition, optionally under homogenization, or else coated in a fluidized-bed system. The period of time of atomization of the coating composition onto the DGP depends upon the amount of pearlizing layer to be anchored on the PGD, the concentration of pearlizing agent and the coating composition. All the steps of the coating process of the present invention are advantageously carried out at ambient temperature and pressure. The thus obtained DGP have a moisture content suitable for their final use and, therefore, they dispense with the additional drying step. The coating process described herein may also be applied to other minerals and mixtures of clayey minerals with inorganic fillers or organic and inorganic salts, as long as they are self-granulating or granulated with the help of agglomerating agents and also tolerate the minimum of 4% of moisture without dissolving. Therefore, the coating process of the present invention has a number of advantages with regard to the operational conditions and the improvements in the final product as in comparison with the known processes. The process of the present invention further brings about excellent dyeing revelation with low concentration of coating agent, and dispenses with the use of organic compounds by using only water as a solvent. It further permits addition of volatile and thermosensitive actives without degrading them or impair their action power, prevents agglomeration of the DGP, redu- ces hygroscopicity of the DGP, and enables reproductibility of colors. These advantages bring about considerable reduction of costs and energy, inputs and equipments. The coated DGP of the present invention is especially suitable for manufacturing softeners and detergent products such as soaps and toilet soaps. It is evident that a person skilled in the art, based on the teachings of this specification, will know how to obtain DGP for other applications. A preferred embodiment having been described, one should understand that the scope of the present invention embraces other possible variations, being limited only by the contents of the accompanying claims, which include the possible equivalents.

Claims

1. A process for coating dried granulated powders, characterized by comprising the following steps: (i) drying granulated powders until a moisture content of 0,0% to 15,0%; (ii) preparing a coating composition; (iii) weighing a predetermined amount of a coating composition; (iv) leading the coating composition in the amount predetermined by weighing to a mixer through a carrier fluid; and (v) applying the coating composition onto the dried granulated powder.

2. A process according to claim 1 , characterized in that the granulated powder is pure bentonite or its combination with one of more clayey minerals, inorganic fillers, inorganic salts and organic salts.

3. A process according to claim 1 , characterized in that the coating composition is applied by atomization.

4. A process according to claim 1 , characterized in that the application of the coating composition is carried out under movement of the granulated powder.

5. A process according to claim 1 , characterized in that the carrier fluid of the coating composition is compressed air.

6. A process according to claim 1 , characterized in that the coating composition is an aqueous suspension comprising a pearlizing agent, a volatile component, a thermosensitive component or a combination thereof.

7. A process according to claim 1 , characterized by being carried out in conditions of ambient temperature and pressure.

8. A process according to claim 4, characterized by being carried out in a dragee-making device or a rotary homogenizer.

9. A process according to claim 6, characterized in that the coa- ting composition comprises 3% to 25% of a coating agent, 0.1% to 1 % of a coloring component, 50% to 90% of one or more active ingredients, 0.1% to 2% of a fixing agent and 10% to 20% of a solvent.

10. A process according to claim 9, characterized in that the coating agent is a white and /or dyeable base.

11. A process according to claim 9 or 10, characterized in that the coating agent is a mica or a mica supported on titanium dioxide.

12. A process according to claim 9, characterized in that the coloring component is a pigment, a dye or combinations thereof.

13. A process according to claim 9, characterized in that the active ingredient is selected from optical bleachers, perfumes, essences, buffers, fragrances, aloe vera, chelants, surfactants, co-builders or combinations the- reof.

14. A process according to claim 9, characterized in that the fixing agent is selected from carboxy methyl cellulose, xanthan gum, emulsi- onns of polyvinyl chloride, resins or combinations thereof.

15. A process according to claim 9, characterized in that the sol- vent is water.

16. A powdered granulate, characterized by being coated in accordance with the process as defined in any one of claims 1 to 15.

17. A detergent product, characterized by comprising granulated powder obtained in accordance with the process defined in any one of claims 1 to 15.

18. A softener, characterized by comprising granulated powder obtained in accordance with the process defined in any one of claims 1 to 15.