EP0993509A1

EP0993509A1 - Coated cleaning product components

Info

Publication number: EP0993509A1
Application number: EP98934968A
Authority: EP
Inventors: Thomas Gassenmeier; Jürgen MILLHOFF; Jürgen Härer; Thomas Möller; Christian Nitsch
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 1997-06-25
Filing date: 1998-06-17
Publication date: 2000-04-19
Also published as: JP2002506476A; WO1999000476A1; DE19727073A1

Abstract

A process is disclosed for producing coated solid particles, as well as coated solid particles. A material with a plastic solidification range and a melting range between 45 °C and 75 °C is used as coating material. The solid particles to be coated should not be less than 0.05 mm large, in particular not less than 0.1 mm large. Also disclosed is the use of the coated solid particles in cleaning products.

Description

Coated detergent component

The invention relates to a method for producing a coated detergent component, the cover consisting of a non-water-soluble substance which has a plastic solidification area. The invention further relates to such coated detergent components and their use in detergents, in particular in detergents, detergents for hard surfaces, automatic dishwashing detergents or hand dishwashing detergents.

Modern cleaning agents contain a large number of components, each of which has specific effects that either support the cleaning process or perform other tasks (for example odor improvement). In addition to the anionic, nonionic and / or cationic surfactants usually present in cleaning agents, enzymes, bleaching agents, bleach activators, fragrances and / or other additives can be contained, for example.

Detergents are generally used diluted, i.e. the actual cleaning process is carried out with the aid of a dilute aqueous solution of the detergent (cleaning liquor). As a rule, the cleaning liquor has an elevated temperature; depending on the area of use of the cleaning agent, the temperature range is usually in a range from 40 ° C. to approximately 95 ° C. Cleaning liquors with low temperatures are usually found where the user comes into manual contact with the cleaning liquor (hand dishwashing liquid, detergent). Higher temperatures can be found, for example, wherever the cleaning process is carried out by machine (machine dishwashing detergent, detergent).

While the large number of components present in the cleaning agent generally has good cleaning power at different temperatures and guarantees a wide variety of soiling, but there are often compatibility problems between individual components. For example, the activity of enzymes, which are contained in the cleaning agent to remove protein-containing soiling, for example, is reduced by bleaching agent activated at the same time. Therefore, more enzymes must either be added to the cleaning agent in order to obtain a high cleaning power, or the cleaning agent has a poorer cleaning effect than would have been expected based on the amount of the enzyme used.

Under certain circumstances, the sensitivity of individual components to external influences, for example to air humidity, can be problematic. For example, bleaching agents such as percarbonates can be broken down by moisture, thermal influences and interactions with other components of the substance mixture present in the cleaning agent, which leads to a loss in bleaching action.

If the cleaning agent contains a bleaching agent (which is generally the case for at least some detergents and in particular for machine dishwashing agents), there is usually also a so-called bleach activator, which causes the bleaching agent (the active oxygen) to be released even at low temperatures. If the bleaching agent and activator are present side by side in the cleaning agent, decomposition of the bleaching agent can already occur during storage under the influence of moisture, which in turn leads to a loss of bleaching activity for the cleaning agent.

A particularly critical situation for the interplay of different substances contained in the cleaning agent exists when the cleaning agent is a liquid-formulated cleaning agent which generally contains at least small amounts of water. This is where the effects of the water content of the liquid, which can be observed with powdered cleaning agents or with granulated cleaning agents, essentially caused by atmospheric moisture, occur formulated detergent to an increased extent. Such interactions are usually not desirable.

It is the rule with conventional cleaning agents, in particular those which are used at high temperature (machine cleaning agents such as machine dishwashing detergents or detergents) that some cleaning agent components develop their effectiveness mainly in lower temperature ranges (for example enzymes) or through certain aggressive ingredients, for example Bleaching agents or washing alkalis can be impaired in their effectiveness. In addition to the enzymes already mentioned, fragrances also belong to this group, for example. In this case, too, it proves to be a disadvantage that certain detergent components are combined with others

Detergent components develop their activity at the same time, which can lead to a mutual reduction in effectiveness and, in the worst case, to a complete blockage of the mechanism of action of individual components

In order to rule out the disadvantages mentioned or at least to mitigate their effects, a preparation form for a cleaning agent is ideal, which retains certain substances (e.g. aggressive substances or sensitive substances) for a certain time in a form that is indifferent to the detergent components that have already been dissolved and which only releases the substances at a later point in time, for example when the cleaning function of the components already dissolved has ended. Ideally, however, the release should then proceed quickly and quantitatively in order to use the highest possible proportion of the active ingredient, preferably the entire active ingredient. A suitable parameter for triggering this release is, for example, the temperature of the cleaning liquor.

There has been no shortage of attempts in the past to isolate individual detergent components from external influences by means of various processes. DE-A 41 29 242 describes a storage-stable encapsulated sodium percarbonate and a process for its production. The aim is to coat anhydrous, solid sodium percarbonate with a hydrophobic protective coating of a coating material that is solid at room temperature. The coating itself takes place in that the finely divided sodium percarbonate is thrown through a spray zone of the molten coating agent. Following contact with the molten coating material, the freshly coated material is taken up by a stream of cooling gas, which leads to an immediate solidification of the casing.

EP-A 0 131 269 relates to granules containing metal chelate complexes and processes for their preparation. A process for the coating of metal chelate complexes of ethylenediaminetetraacetic acid (H ₄ EDTA) is described, in which the pulverized metal chelate complexes are mixed with the melt of the coating and homogenized. The liquid dispersion is then further processed in a pastilling plant or in a scaling plant to form relatively large pastilles or flakes. Processing of the molten mixture of binder and metal chelate complex in extrusion and hole presses or in extruders is also mentioned. The products available in this way are described in that they dissolve more slowly in water than the pure metal chelate complexes. There is talk of a delay effect, the influence of the ambient temperature is not mentioned in the document.

US Pat. No. 5,258,132 describes particles which are provided with a single-layer coating of paraffin wax with a melting point of about 40 to 50 ° C. The coated particles are produced by spray coating, in which a fluidized bed with solid particles is treated with the melted paraffin wax either from above or from below.

WO 95/30735 also relates to solid particles coated with a coating which is solid at room temperature, the coating of which consists of a polyvinyl ether / paraffin wax mixture. The coating is applied by spraying in the fluid bed. However, the methods known from the prior art for coating solid, generally water-soluble or at least water-dispersible particles with coating agents solid at room temperature have various disadvantages on closer inspection.

The widespread spray coating method results in extremely finely divided coated particles, but as a rule the coating is not completely tight, so that active substance is released as soon as it is introduced into water. As a rule, corners and edges of the usually irregularly shaped, solid substrate are only incompletely covered by the covering during spray coating. When entering water, this usually leads to the fact that relatively much of the coated active substance can quickly escape into the surrounding water and the desired effect does not occur at all, or only occurs in a weakened form.

It was therefore an object of the invention to find a process by which detergent components can be coated with a non-water-soluble coating, so that the coated, generally water-soluble or at least water-dispersible component is very slow or only up to a certain temperature in an aqueous environment a certain percentage is released. Ideally, there is no release at all below a certain temperature. Furthermore, it was an object of the invention to provide a process for producing a coated detergent component in which the coated detergent component releases the contents as quickly and as completely as possible in an aqueous environment when the water temperature is raised to a value above the lower limit of the melting range of the casing .

It has now been found that the process of melt embedding with a subsequent granulation step in a temperature range in which the coating is in the plastic solidification range leads to coated solid particles which do not have the above-mentioned disadvantages of the prior art. Surprisingly, it was found that the coated solid particles only then if the lower limit of the melting range of the coating is exceeded, they are released particularly quickly and completely if they meet certain criteria with regard to their particle size, in particular also with regard to their crystallinity.

The invention therefore relates to a process for the production of coated solid particles, in which the solid particles are dispersed in the melt of a largely water-insoluble substance (coating) which is solid at room temperature and has a plastic solidification range, the dispersion is cooled, and at a temperature which is in the plastic solidification area of the casing, is granulated, the solid particles having a particle diameter of at least 0.05 mm.

Various requirements are imposed on the coating of the solid particles, which on the one hand relate to the melting or solidification behavior, but on the other hand also relate to the material properties of the coating in the solidified area at ambient temperature. Since the casing is intended to permanently protect the solid particles enclosed therein against environmental influences during transport or storage, it must have a high stability against, for example, shock loads occurring during transport or transfer operations, in particular collisions with other particles or vessel walls. The covering should therefore either have at least partially elastic or at least plastic properties, in order to react to an occurring shock load due to elastic or plastic deformation and not to break. The coating should have a melting range (solidification range) in such a temperature range in which the solid particles to be coated are not exposed to excessive thermal stress. On the other hand, however, the melting range must be sufficiently high to still provide effective protection for the enclosed particles at at least a slightly elevated temperature.

It has proven to be advantageous if the sheathing does not show a sharply defined melting point, as is usually the case with pure, crystalline substances, but rather a melting range that may include several degrees Celsius having.

The covering preferably has a melting range which is between approximately 45 ° C. and approximately 75 ° C., particularly preferably between approximately 50 ° C. and approximately 60 ° C. In the present case, this means that the melting range occurs within the specified temperature interval and does not indicate the width of the melting range.

The width of the melting range is preferably at least 1 ° C., preferably about 2 to about 3 ° C.

The properties mentioned above are usually fulfilled by so-called waxes. "Waxing" is understood to mean a number of natural or artificially obtained substances which generally melt above 40 ° C. without decomposition and which are relatively low-viscosity and not stringy even a little above the melting point. They have a strongly temperature-dependent consistency and solubility.

The waxes are divided into three groups according to their origin, natural waxes, chemically modified waxes and synthetic waxes.

Natural waxes include, for example, vegetable waxes such as candelilla wax, carnauba wax, japan wax, esparto grass wax, cork wax, guaruma wax, rice germ oil wax, sugar cane wax, ouricury wax, or montan wax, animal waxes such as beeswax, shellac wax, walnut, lanolin (wool wax), or furs, mineral wax such as ceresin or ozokerite (earth wax), or petrochemical waxes such as petrolatum, paraffin waxes or micro waxes.

The chemically modified waxes include hard waxes such as montan ester waxes, Sassol waxes or hydrogenated jojoba waxes.

Synthetic waxes are generally understood to mean polyalkylene waxes or polyalkylene glycol waxes. Can also be used as wrapping materials Compounds from other classes of substances that meet the stated softening point requirements. Higher esters of phthalic acid, in particular dicyclohexyl phthalate, which is commercially available under the name Unimolf 66 (Bayer AG), have proven to be suitable synthetic compounds, for example. Also suitable are synthetically produced waxes from lower carboxylic acids and fatty alcohols, for example dimyristyl tartrate, which is available under the name Cosmacof ETLP (Condea). Conversely, synthetic or partially synthetic esters from lower alcohols with fatty acids from native sources can also be used. Tegin ⁹ 90 (Goldschmidt), a glycerol monostearate palmitate, falls into this class of substances. Shellac, for example Shellac-KPS-Dreiring-SP (Kalkhoff GmbH), can also be used according to the invention as a coating material.

The so-called wax alcohols are also included in the waxes in the context of the present invention, for example. Wax alcohols are higher molecular weight, water-insoluble fatty alcohols with usually about 22 to 40 carbon atoms. The wax alcohols occur, for example, in the form of wax esters of higher molecular fatty acids (wax acids) as the main component of many natural waxes. Examples of wax alcohols are lignoceryl alcohol (1-tetracosanol), cetyl alcohol, myristyl alcohol or melissyl alcohol. The coating of the present invention the solid particles coated can optionally also contain wool wax alcohols which are understood to be triterpenoid and steroid alcohols, for example lanolin understands that bbeispielsweiseunter the trade designation Argowax ^® (Pamentier & Co) is available. Fatty acid glycerol esters or fatty acid alkanolamides, but optionally also water-insoluble or only slightly water-soluble polyalkylene glycol compounds, can likewise be used at least in part as a component of the casing.

The coating used in the method according to the invention preferably contains the majority of paraffin wax. This means that at least 50% by weight of the covering, preferably more, consists of paraffin wax. Paraffin wax contents in the coating of approximately 60% by weight, approximately 70% by weight or approximately 80% by weight are particularly suitable, with even higher proportions of, for example, more than 90% by weight being particularly preferred are preferred. In a special embodiment of the invention, the covering consists exclusively of paraffin wax.

In the context of the present invention, paraffin waxes have the advantage over the other natural waxes mentioned that there is no hydrolysis of the waxes in an alkaline cleaning agent environment (as is to be expected, for example, from the wax esters), since paraffin wax contains no hydrolyzable groups.

Paraffin waxes consist mainly of alkanes and low levels of iso- and cycloalkanes. The paraffin to be used according to the invention preferably has essentially no constituents with a melting point of more than 70 ° C., particularly preferably of more than 60 ° C. Portions of high-melting alkanes in the paraffin can leave undesired wax residues on the surfaces to be cleaned or the goods to be cleaned if the melting temperature in the detergent solution drops below this. Such wax residues usually lead to an unsightly appearance on the cleaned surface and should therefore be avoided.

The coating according to the invention preferably contains at least one paraffin wax with a melting point of about 50 ° C. to about 55 ° C.

Preferably, the paraffin wax content of alkanes, isoalkanes and cycloalkanes which are solid at ambient temperature (generally about 10 to about 30 ° C.) is as high as possible. The more solid wax components present in a wax at room temperature, the more useful it is within the scope of the present invention. With increasing proportion of solid wax components, the resilience of the coating to impacts or friction on other surfaces increases, which leads to a longer-lasting protection of the coated solid particles. High proportions of oils or liquid wax components can weaken the coating, opening pores and exposing the coated solid particles to the environmental influences mentioned at the beginning. At exceptionally low temperatures, for example at temperatures below 0 ° C, the casing can break under impact or friction. In order to improve the stability at such low temperatures, additives can optionally be added to the coating. Suitable additives must be able to be mixed completely with the molten wax, must not significantly change the melting range of the casing, must improve the elasticity of the casing at low temperatures, must not generally increase the permeability of the casing to water or moisture and must not increase the viscosity of the melt of the wrapping material should not be increased to such an extent that processing becomes difficult or even impossible. Suitable additives which reduce the brittleness of a sheath consisting essentially of paraffin at low temperatures are, for example, EVA copolymers, hydrogenated resin acid methyl ester, polyethylene or copolymers of ethyl acrylate and 2-ethylhexyl acrylate.

Another useful additive when using paraffin as a coating is the addition of a small amount of a surfactant, for example a C _{12 lg} fatty alcohol sulfate. This addition results in a better wetting of the material to be embedded through the covering. It is advantageous to add the additive in an amount of about <5% by weight, preferably <about 2% by weight, based on the coating. The addition of an additive can in many cases lead to the fact that solid particles can also be encased which, without the addition of additives, generally form a tough, plastic body made of paraffin and partially dissolved solid particles after the encapsulation material has melted.

In the method according to the invention, it may be advantageous to add further additives to the coating material, for example to prevent the particles to be coated from settling prematurely during cooling. The anti-settling agents that can be used for this purpose, which are also referred to as floating agents, are known from the prior art, for example from the manufacture of lacquers and printing inks. In order to show sedimentation phenomena during the transition from the plastic primary area to the solid and to avoid concentration differences in the substances to be coated, for example, surface-active substances, waxes dispersed in solvents, montmorillonites, organically modified bentonites, (hydrogenated) castor oil derivatives, soy lecithin, ethyl cellulose, low-molecular polyamides, metal stearates, calcium soaps or hydrophobicized silicic acids are suitable. Other substances that bring about the effects mentioned come from the groups of anti-floating agents and thixotropic agents and can be chemically used as silicone oils (dimethylpolysiloxanes, methylphenylpolysiloxanes, polyether-modified methylalkylpolysiloxanes), oligomeric titanates and silanes, polyamines, salts from long-chain polyamines and polycarboxylic acids, amine / Amide-functional polyesters or amine / amide-functional polyacrylates. Additives from the substance classes mentioned are commercially available in a wide variety. Commercial products, which can be added as an additive in the context of advantageous of the method according to the invention are, for example Aerosi 200 (pyrogenic silicic acid, Degussa), Bentone ^® SD-1, SD-2, 34, 52 and 57 (bentonite, Rheox), Bentone ^* SD -3, 27 and 38 (hectorite, Rheox), Tixogef EZ 100 or VP-A (organically modified smectite, Südchemie), Tixogef VG, VP and VZ (montmorillonite loaded with QAV, Südchemie), Disperbyk ^® 161 (block copolymer, Byk- Chemistry), Borchigen ND (sulfo group-free ion exchanger, Borchers), Ser-Ad ^® FA 601 (servo), Solsperse ^® (aromatic ethoxylate, ICI), Surfynof types (Air Products), Tamof and Triton ^β types (Rohm & Haas), Texaphor ^® 963, 3241 and 3250 (polymers, Henkel), Rilanit ^® types (Henkel), Thixcin ^® E and R (castor oil derivatives, Rheox), Thixatrof ST and GST (castor oil derivatives, Rheox), Thixatrof SR, SR 100, TSR and TSR 100 (polyamide polymers, Rheox), Thixatrof 289 (polyetsre polymer, Rheox) and the different MPA ^® -Ty pen X, 60-X, 1078-X, 2000-X and 60-MS (organic compounds, Rheox).

The auxiliaries mentioned can be used in varying amounts in the process according to the invention, depending on the wrapping material and the material to be wrapped. Usual use concentrations for the abovementioned anti-settling, anti-floating, thioxotropic and dispersing agents are in the range from 0.5 to 8.0% by weight, preferably between 1.0 and 5.0% by weight, and particularly preferably between 1.5 and 3.0% by weight, each based on the end product of the process. In addition to paraffin, the coating can also contain one or more of the above-mentioned waxes or wax-like substances as the main constituent. In principle, the mixture forming the cover should be such that the cover is at least largely water-insoluble. The solubility in water should not exceed about 10 mg / 1 at a temperature of about 30 ° C. and should preferably be below 5 mg / 1.

In any case, however, the coating should have the lowest possible solubility in water, even in water at an elevated temperature, in order to avoid the temperature-independent release of the coated solid particles as far as possible.

The term "solid particles", as used in the context of the present text, basically refers to any form of solid materials which can be embedded in an envelope, as described in the context of the present invention, to protect against external influences. The solid particles have a particle diameter of at least 0.05 mm, but the particle diameter is preferably above, for example between about 0.1 and about 0.3 mm and particularly preferably between about 0.15 and about 0.25 mm (determined by Sieve analysis). In the case of certain substances to be coated, however, this particle size range can advantageously also be shifted towards higher values, so that the particle sizes are between 0.5 and 2 mm, preferably between 1.0 and 1.5 mm. Substances that are preferably used coarser, ie within the latter particle size range, are, for example, bleaching agents.

It is particularly preferred in the context of the present invention in some cases if the individual particles, i.e. the solid particles to be coated, are present in crystalline form.

However, the term “solid particles” preferably refers to those solids that are usually used in the context of an application as part of a cleaning agent. In particular, the term "solid particles" refers to such Detergent components which are unstable to external influences, for example moisture, also in the form of atmospheric moisture, or which are incompatible with at least one further component present in the detergent. Such solid particles include, but are not limited to, enzymes, bleaching agents, bleach activators, surfactants and / or fragrances.

The solid particles themselves form about 10 to about 90% by weight of the total mass of the coated solid particles. The coating is usually the 100% by weight missing portion. It is conceivable that the entire covering does not consist of only one layer, but that several layers of different substances may also be applied as the covering. This can be done, for example, in order to influence not only a temperature-dependent dissolution process but also further parameters (for example low initial water solubility or the hardness of the outer casing) of the casing. In the context of the present text, the term “wrapping” also encompasses wrapping composed of two or more layers, unless expressly stated otherwise.

The proportion of the solid particles in the total mass of the coated solid particles is preferably approximately 30% by weight to approximately 75% by weight, particularly preferably approximately 35% by weight to approximately 60% by weight.

The substances listed below are particularly suitable as solid particles. The coated solid particles according to the invention can be used in any type of cleaning agent in which a component has to be protected against external influences or other substances present in the mixture of the component.

Bleaching agents, for example, are suitable as solid particles. For example, chlorine or bromine-releasing substances or peroxides, preferably organic peroxides or inorganic peroxides, the latter preferably in the form of their alkali metal salts, can be used as bleaching agents. Suitable chlorine or bromine-releasing materials include, for example, heterocyclic N-bromo- and N-chloramides, for example trichloroisocyanuric acid, tribromoisocyanuric acid, dibromoisocyanuric acid and / or dichloroisocyanuric acid (DICA) and / or their salts with cations such as potassium and sodium. Hydantoin compounds such as 1,3-dichloro-5,5-dimethylhydanthoin are also suitable.

Anhydrous, water-soluble inorganic salts are also suitable as bleaching agents, e.g. Lithium, sodium or calcium hypochlorite and hypobromite. Chlorinated trisodium phosphate is another material suitable as a bleaching agent.

Organic peracids and diacyl peroxides can also be used as bleaching agents. The peracids which can be used in the context of the present invention are solids and are stable in a temperature range which corresponds to the melting range of the coating or is still somewhat above this melting range (approximately up to 10 ° C. above the melting range). Typical monoperoxy acids are, for example, alkyl and aryl peroxy acids such as peroxybenzoic acid and their analogs substituted on the benzene ring, aliphatic and substituted aliphatic monoperoxy acids, for example peroxylauric acid or peroxy stearic acid, alkyldiperoxyacids and aryldiperoxyacids such as 1,12-diperoxydodicacidoxyperoxy acid, 1,9-diperoxydylacidoxyperoxy acid, 1,9-doxydoxyacid oxyacid, . For example, phthalimidoperoxyhexanoic acid (PAP) has also proven to be particularly suitable. The aryldiperoxy acids that can be used in the context of the invention include, for example, dibenzoyl peroxide.

The inorganic peroxy compounds which can be used in the context of the present invention include, for example, monopersulfates, perborates and percarbonates. The inorganic peroxy compounds are generally used as alkali salts, preferably as lithium, sodium or potassium salts.

As already mentioned above, it can have process engineering advantages if the bleaching agents are relatively coarse, ie within the particle size range from 0.5 to 2.0 mm, preferably from 1.0 to 1.5 mm.

As enzymes that can be used in the context of the present invention, for example proteases, amylases, lipases and oxidases come into question.

Bleach catalysts are also suitable as solid particles in the context of the present invention. These include, for example, manganese salt compounds or complexes, azirdirine compounds or sulfonimine compounds. For use in the context of the present compound, the catalysts are preferably adsorbed on a substrate as a carrier component or at least mixed with the latter in order to achieve the particle size prescribed in the context of the present invention.

Bleach activators in particular are suitable as solid particles in the context of the present invention. Bleach activators are added to detergents containing bleach, since the bleaches containing active oxygen generally only release the active oxygen at elevated temperatures. The bleach activators thus enable accelerated release of the active oxygen from the salt containing active oxygen, as is required, for example, in machine-based cleaning agents, for example in machine dishwashing detergents or detergents, even at a relatively low temperature (compared to the temperature required without activators). As a rule, this temperature is approximately above 50 ° C., preferably approximately 60 ° C. In the context of the invention, bleach activators which can be used are, for example, pentaacetylglucose (PAG), l, 5-diacetyl-2,2-dioxohexahydro-l, 3,5-triazine (DAEHT) and isatoic acid amide (ISA). However, N, N, N'N'-tetraacetylethylene diamine (TAED) is particularly preferred for use in the process according to the invention.

Bleach stabilizers, for example, can also be used as solid particles in the context of the present invention. The bleach stabilizers include, in particular, phosphonates, borates or metaborates and metasilicates, and also magnesium salts, for example magnesium sulfate. It may also be necessary to use surfactants as solid particles. For example, if chlorine-containing bleaches and nonionic surfactants, in particular alkoxylated alcohols, are present at the same time, interactions between bleach and surfactant can occur. In such a case, the surfactants can be encapsulated, for example. With the encapsulation of surfactants, for example, it is also possible to use cationic and anionic surfactants in a single cleaning agent without direct interactions between the two different types of surfactants. Anionic, cationic or nonionic surfactants which can be used are all types of surfactants commonly used in detergents, provided they are solids or have been brought into a solid form (for example by adsorption on a support) and have a particle size of more than 0.05 mm , preferably more than 0.1 mm.

If necessary, it is also possible in the context of the present invention to encase liquid or at least pasty substances. For this purpose, the liquid or, if necessary, the paste-like substances are adsorbed on a suitable carrier material, so that the adsorbate fulfills the conditions according to the invention with regard to state of matter and particle size.

Different methods are conceivable for applying the coating to the solid particles. A so-called "coating" is a widespread and long-known method. In this method, extremely fine-particle solids, for example in a fluidized bed arrangement or in a fluidized bed, are sprayed with a molten coating composition or with a Mist from melted coating mass brought into contact. Here, the solids are encased with the coating layer, essentially in the form of their individual particles. On closer inspection (for example microscopic) of individual coated particles, however, it is found that the coating does not completely coat the individual particles due to their generally irregular shape. As a result, parts of the enclosed solid are still exposed to environmental influences, which is particularly the case when the incompletely coated solids are introduced into an aqueous environment Days occurs. Since the water has at least partially unhindered access to the solid due to the incomplete coating, solid particles coated in this conventional manner generally only show a time-delayed dissolution behavior in an aqueous environment at a temperature below the melting point of the coating, a complete suppression of the release of the coated Material at a temperature below the melting point of the casing or a release that has ended rapidly at least after an initial rise can generally not be achieved in this way.

Therefore, in the context of the present invention, the process of melt embedding was chosen for embedding the solid particles. Here, the solid to be coated is first dispersed in a melt of the covering material. The temperature of the melt must meet two conditions. Firstly, it must be sufficiently high to produce a melt which is as low-viscosity as possible during the dispersion process. On the other hand, however, it must be at a sufficient distance from the temperature which triggers a chemical reaction, for example decomposition, in the solid to be coated. Due to the dispersion of the material to be wrapped in the melt of the wrapping material, the wrapping material is initially essentially completely enclosed by the wrapping material. This is a basic requirement for obtaining essentially completely encased solid particles.

In a next step, the dispersion is cooled to a temperature that is approximately in the plastic solidification range of the melt. A plastic solidification area is understood to mean an area in which the melt on the one hand has a sufficiently high viscosity to keep the solid particles dispersed therein in a stable dispersion, and on the other hand also has enough plasticity and flowability to easily break without breaking or tearing to be deformable and shearable.

The temperature can be varied within the plastic solidification range of the coating material so that, for example, an almost liquid, but in any case still flowable mass is obtained up to masses that are no longer flowable. which only show a certain plastic deformability under the influence of external forces. Between these two forms, the mass of coating and solid particles shows a "pasty" behavior.

After cooling, the mixture of solid particles and coating composition is subjected to granulation. In the context of the present application, the term “granulation” denotes any shaping process that leads to particles of predeterminable size. In addition to the conventional granulation and agglomeration processes, which can be carried out in a wide variety of mixing granulators and mixing agglomerators, press agglomeration processes can also be used.

The process according to the invention can be carried out in a large number of apparatuses customarily used in the detergent and cleaning agent industry. For example, it is possible to use the rounding agents commonly used in pharmacy. In such turntable devices, the residence time of the solid particles to be coated is usually less than 20 seconds.

Conventional mixers and mixing granulators are also suitable for carrying out the process according to the invention. Both high-intensity mixers ("high-shear mixers") and normal mixers with lower circulation speeds can be used as mixers. Suitable mixers are, for example, Eiriclf mixers of the R or RV series (trademark of Maschinenfabrik Gustav Eirich, Hardheim), Schug Flexomix, the Fukae ^® FS-G mixers (trademark of Fukae Powtech, Kogyo Co., Japan), the Lödige ^® FM, KM and CB mixers (trademarks of Lödige Maschinenbau GmbH, Paderborn) or the Drais ^E series T or KT (trademarks of Drais-Werke GmbH, Mannheim). The residence times of the solid particles to be coated in the mixers are in the range of less than 60 seconds, the residence time also being dependent on the speed of circulation of the mixer. The dwell times are reduced accordingly the faster the mixer runs. The residence times of the granules to be coated in the mixer / rounder are preferably less than one minute, preferably less than 15 seconds. In the press agglomeration process, the mixture of encapsulation material and solid particles in the plastic solidification area of the encapsulation is compressed under pressure and under the action of shear forces and homogenized in the process and then discharged from the apparatus in a shaping manner. The technically most important press agglomeration processes are extrusion, roller compaction, pelleting and tableting. In the context of the present invention, preferred press agglomeration processes are extrusion, roller compaction and pelletization.

In a preferred embodiment of the invention, the mixture of coating material and solid particles in the plastic solidification area of the coating is preferably fed continuously to a planetary roller extruder or a 2-shaft extruder or 2-screw extruder with co-rotating or counter-rotating screw guide, its housing and its extruder. Granulating head can be heated to the predetermined extrusion temperature. Under the shear action of the extruder screws, the premix is compressed, plasticized, extruded in the form of fine strands through the perforated die plate in the extruder head and under pressure, which is preferably at least 25 bar, but can also be lower at extremely high throughputs depending on the apparatus used finally, the extrudate is preferably reduced to approximately spherical to cylindrical granules by means of a rotating knives. The hole diameter of the perforated nozzle plate and the strand cut length are matched to the selected granulate dimension. In this embodiment, the production of granules of an essentially uniformly predeterminable particle size succeeds, and in particular the absolute particle sizes can be adapted to the intended use. In general, particle diameters up to at most 0.8 cm are preferred. Important embodiments provide for the production of uniform granules in the millimeter range, for example in the range from 0.5 to 5 mm and in particular in the range from approximately 0.8 to 3 mm. In an important embodiment, the length / diameter ratio of the chopped-off primary granules is in the range from about 1: 1 to about 3: 1. It is further preferred that the still plastic primary granules are combined to supply further shaping processing step; edges present on the crude extrudate are rounded off so that ultimately spherical to approximately spherical extrudate grains can be obtained. Instead of knocking off the extruded strands to form granules, it is also possible to meter an extrusion strand into predetermined shapes. This design of the method is recommended, for example, when filling molded articles which have prefabricated troughs. In the context of the present invention, it is preferred to produce detergent tablets according to known processes which have a fillable region (“trough”) which is subsequently filled in the manner described above with an enveloped detergent component, by the mixture of wrapping material and solid particles in the plastic solidification area of the casing are pressed into the trough, that is to say extruded.

Alternatively, extrusions / pressings can also be carried out in low-pressure extruders, in the Kahl press or in the extruder.

In a further preferred embodiment of the present invention, the method according to the invention is carried out by means of roller compaction. Here, the mixture of coating material and solid particles in the plastic solidification area of the coating is metered in between two smooth rollers or with recesses of a defined shape and rolled under pressure between the two rollers to form a sheet-like compact, the so-called Schülpe. The rollers exert a high line pressure on the premix and can be additionally heated or cooled as required. When using smooth rollers, smooth, unstructured sliver belts are obtained, while by using structured rollers, correspondingly structured slugs or individual pellets can be produced, in which, for example, certain shapes of the later granules or shaped bodies can be specified. The sliver belt is subsequently broken up into smaller pieces by a knocking-off and comminution process and can in this way be processed into granules which are further tempered by further known surface treatment methods, in particular in approximately spherical can be shaped.

In a further preferred embodiment of the present invention, the method according to the invention is carried out by means of pelleting. The mixture of coating material and solid particles in the plastic solidification area of the coating is applied to a perforated surface and pressed through the holes by means of a pressure-generating body. In conventional embodiments of pellet presses, the mixture of coating material and solid particles in the plastic solidification area of the coating is compressed under pressure, plasticized, pressed by means of a rotating roller in the form of fine strands through a perforated surface and finally comminuted into granules using a knock-off device. The most varied configurations of the pressure roller and perforated die are conceivable here. For example, flat perforated plates are used as well as concave or convex ring matrices through which the material is pressed using one or more pressure rollers. The press rolls can also be conical in the plate devices, in the ring-shaped devices dies and press roll (s) can have the same or opposite direction of rotation. An apparatus suitable for carrying out the method according to the invention is described, for example, in German laid-open specification DE 38 16 842 (Schlüter GmbH). The ring die press disclosed in this document consists of a rotating ring die penetrated by press channels and at least one press roller which is operatively connected to the inner surface thereof and presses the material supplied to the die space through the press channels into a material discharge. Here, the ring die and the press roller can be driven in the same direction, which means that a reduced shear stress and thus a lower temperature increase in the premix can be achieved. Of course, it is also possible to work with heatable or coolable rollers in the pelletizing in order to set a desired temperature of the premix.

Another press agglomeration process that can be used according to the invention is tableting. In this method, the mixture of coating material and solid particles in the plastic solidification area of the coating in one The die is pressed in a form-giving manner, with solid particles in a wide variety of shapes being able to be produced via the design of the upper and lower punches of the tablet press.

The granulation process is advantageously chosen so that the granules allow the planned use of the coated solid particles without any further processing step. For the preferred use of the coated solid particles in cleaning agents in the context of the present invention, the granules are granulated to a particle size of at most up to about 2 mm, preferably to an underlying value, for example 1.5 mm or 1 mm. For certain applications, even smaller particle diameters can be sought for the granules, the lower limit of the particle size being determined by the minimum size of the coated solid particles plus the thickness of the coating. Preferred particle diameters for the granules are therefore in the range of approximately one millimeter or slightly less, for example in a range of approximately 0.5 mm to 1 mm.

For certain applications it can be advantageous if the particle sizes of the coated solid particles including the coating are above the values mentioned above. As described above, for bleaching agents, for example, larger particle sizes of the particles to be coated - and thus also of the coated particles - are of particular advantage for some areas of application. The process of controlled release of certain detergent and cleaning agent ingredients can be supported by the particle sizes of the coated solid particles. For example, in the case of cleaning agents for automatic dishwashing, it is advantageous if the particle sizes of the coated solid particles, including the coating, are significantly larger than the mesh size of the sieve insert of the dishwashers. This prevents the coated solids that have not yet been released from being pumped out after the pre-rinse cycle, and the coated solid particles can develop their effect in the main rinse cycle. Preferred particle sizes of the coated solid particles including the coating for the stated purpose are therefore in the range from 0.5 to 10 mm, preferably between 0.8 and 8 mm and in particular between 1 and 5 mm.

In a particularly preferred embodiment, the plastically solidified mass of solid particles and coating material is subjected to a screen granulation process. Preferred sieves have a mesh size within the maximum particle diameter for the granules of up to about 2 mm.

As a rule, a granulate obtained from coated solid particles by the process according to the invention contains more than one solid particle. In contrast to the methods described at the outset, in which the particles are usually individually provided with a coating, the method according to the invention has a decisive advantage. While in the case of conventionally coated solid particles, an incomplete coating renders the entire particle unusable, an irregularity, for example a crack in the coating of the granules according to the invention, only leads to the unusability of the respective solid particles lying in the area of influence of the irregularity in the affected area of the granules. Solid particles that lie further inside the granulate or on an opposite side of the crack, for example, are generally not affected by this action. The method according to the invention thus leads to a larger number of completely coated particles in comparison with conventional coating methods and thus to an improved shielding of the solid particles from external influences.

The invention thus also relates to coated solid particles, obtainable by dispersing solid particles in the melt of a non-water-soluble substance (coating) which is solid at room temperature and has a plastic solidification range, the dispersion is cooled, and at a temperature in the plastic solidification range of the coating is granulated, the solid particles having a particle diameter of at least 0.05 mm, in particular at least 0.1 mm. The solid particles according to the invention are distinguished in that they release less than 30% by weight of the solid particles in water at a temperature of up to 6 ° C. with the onset of the melting range of the coating after 10 minutes. The term "release" refers to all processes that lead to the detection of the solid in the water, in particular to the dissolution of the solid particles in the water.

in cases in which a particularly sensitive material is to be embedded, for example a particularly water-sensitive material, one or more further coating steps can follow after the coating of the material by melt embedding. These can be, for example, further melt embedding steps, the embedding temperature being below the melting range of the casing applied first. However, the further coating steps can equally well be coating processes, in which the coated solid particles present after melt embedding and granulation are individually provided with one or more further coatings.

For example, it can be advantageous if the coated solid particles are coated after the granulation with at least one second coating made of a cellulose derivative or a mixture of two or more cellulose derivatives. This is particularly suitable Methylhydroxy ethyl cellulose (Tylose ^® MH 50, Henkel, Dusseldorf). If necessary, at least one further, for example a third, covering can also be applied to the at least one second covering. Advantageous results can be achieved if, for example, a further paraffin layer is applied as the third covering, the melting range of which is below the melting range of the first covering, for example at approximately 28 to approximately 30 ° C.

The granules according to the invention can be used in any detergents, for example in detergents, in detergents for hard surfaces, in dishwashing machines or in hand dishwashing detergents. The cleaning agents can be present as solids, for example as powders or as granules, but the coated solid particles according to the invention can also be in liquid cleaning agents are used, which can be both water-containing and water-free.

The end products of the process according to the invention can be added in the form of the granules to customary washing and cleaning agents. However, it is also possible to remelt the granules obtained according to the invention and to pour them into cavities in the form of this melt. This procedure is particularly recommended for detergent tablets in which a prefabricated cavity, for example a depression, is poured out.

The invention thus also relates to the use of the coated solid particles according to the invention, in detergents, in particular in detergents, detergents for hard surfaces, automatic dishwashing detergents or hand dishwashing detergents. The present invention also relates to the use of the coated solid particles as a compact phase, for example in the form of a poured depression, in detergent tablets.

The cleaning agents in which the coated solid particles are used can generally (insofar as the coated solid particles do not themselves represent an element from this group) contain compounds from the group of anionic surfactants. Typical examples of anionic surfactants are alkylbenzene sulfonates, alkane sulfonates, olefin sulfonates, alkyl ether sulfonates, glycerol ether sulfonates, sulfo fatty acids, alkyl sulfates, fatty alcohol ether sulfates, glycerol ether sulfates,

Hydroxy ether sulfates, monoglyceride (ether) sulfates, fatty acid amide (ether) sulfates,

Dialkylsulfosuccinates, mono- and dialkylsulfosuccinates, sulfotriglycerin, amide soaps, ether carboxylic acids and their salts, fatty acid isothionates, fatty acid sarcosinates, fatty acid aurides, acyl lactamates, acyl oligoglycoside sulfates, protein fatty acid condensates (from vegetable phosphates in particular) or from two (especially vegetable-based phosphates) or mixtures thereof (from vegetable phosphates or more).

Can also be used together with the coated solid particles according to the invention are non-ionic surfactants. Typical examples of nonionic surfactants are fatty alcohol polyalkylene ethers, preferably with ethylene or propylene oxide units, alkylphenol polyalkylene ethers, preferably with ethylene oxide or propylene oxide units, fatty acid polyalkylene esters, preferably with ethylene oxide or propylene oxide units, fatty acid amide polyalkylene ethers, preferably with ethylene oxide or

Propylene oxide units, fatty amine polyalkylene ethers, preferably with ethylene oxide or propylene oxide units, alkoxylated triglycerol, preferably alkoxylated with ethylene oxide or propylene oxide, alk (en) yl oligoglucosides, fatty acid N-alkyl glucamides, protein fatty acid condensates, polyol fatty acid esters, sugar esters, sorbitan esters and polysorbates. If the nonionic surfactants contain polyalkylene ether chains, they can have a conventional, but preferably a narrow, homolog distribution.

The solid particles coated according to the invention can, for example, also be used together with so-called washing alkali. Washing alkali is understood to mean, for example, amorphous alkali silicate, in particular sodium metasilicate of the composition Na ₂ O: SiO ₂ of about 1: 0.8 to 1: 1.3, preferably about 1: 1, which is generally used in anhydrous form. In addition to the metasilicate or instead of the metasilicate, anhydrous akali carbonate, preferably sodium carbonate or potassium carbonate, is also suitable.

Sequestering agents can also be used together with the coated solid particles according to the invention. Typical sequestering agents are those from the class of aminopolycarboxylic acids and polyphosphoric acids. Aminopolycarboxylic acids include, for example, nitrilotritic acetic acid, ethylenediaminetetraacetic acid,

Diethylenetriamine tetraacetic acid and its higher homologues. Suitable polyphophonic acids are 1-hydroxy ethane-1, 1-diphosphonic acid,

Aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid) and their higher homologues, such as diethylenetetraminetetra (methylenephosphonic acid). The acids mentioned above are usually used in the form of their alkali metal salts, in particular the sodium or potassium salts. Suitable sequestrants also include monomeric polycarboxylic acids or hydroxypolycarboxylic acids, in particular in the form of the alkali salts, for example sodium citrate and / or sodium gluconate.

Likewise usable as sequestering agents (often also referred to as co-builders) are homopolymeric and / or copolymeric carboxylic acids or their alkali metal salts, with the sodium or potassium salts being preferred. Polymer carboxylates or polymeric carboxylic acids with a relative molecular weight of at least 350, in the form of their water-soluble salts, in particular in the form of the sodium and / or potassium salts, have proven to be particularly suitable, for example polyacrylates, polyhydroxyacrylates, polymethacrylates, polymaleates and in particular copolymers of Acrylic acid with maleic acid or maleic anhydride, preferably those from 50 to 70% by weight of acrylic acid and 50 to 10% by weight of maleic acid, as are characterized, for example, in EP-A 0 022 551. The relative molar mass of the homopolymers is generally between 1,000 and 100,000, that of the copolymers between about 2,000 and about 200,000, preferably 50,000 to 120,000, based on free acid. Also suitable compounds of this class are copolymers of acrylic acid or methacrylic acid with vinyl ethers, for example vinyl methyl ether, vinyl esters, ethylene, propylene and / or styrene, in which the proportion of the acid is at least 50% by weight. Terpolymers which contain two carboxylic acids and / or their salts as monomers as well as vinyl alcohol and / or a vinyl alcohol derivative or a carbohydrate as monomers can also be used as polymeric carboxylates or carboxylic acids. Also useful are polyacetal carboxylic acids, as described, for example, in US Pat. Nos. 4,144,226 and 4,146,495, which are obtained by polymerizing esters of glycolic acid, introducing stable terminal end groups and saponifying the respective sodium or potassium salts. Also suitable are polymeric acids which are obtained by polymerizing acrolein and disproportionating the polymer according to Canizzaro using strong alkalis. They are essentially made up of acrylic acid units and vinyl alcohol units or acrolein units.

Cationic surfactants or amphoteric surfactants, for example, can also be used together with the coated solid particles according to the invention. The invention is illustrated below by examples, which, however, are not to be understood as a limitation of the invention.

Examples

Example 1: Embedding DICA

Dichloroisocyanuric acid (DICA) was embedded in paraffin according to the following recipe:

DICA: 35% by weight

Tylose MH 50 15% by weight

Paraffin 50% by weight

Example 2: Embedding of sodium carbonate

Sodium carbonate 50 wt. -%

C ₁₂ . ₁₈ -Fatty alcohol sulfate 2.5% by weight paraffin 47.5% by weight

Example 3: Embedding of sodium hydrogen sulfate

Sodium hydrogen sulfate 40% by weight water-soluble cellulose ether 10% by weight

C ₁₂ .ι ₈ fatty alcohol sulfate 2.5 wt .-%

Paraffin 47.5% by weight

Example 4: Embedding and release of TAED

Crystalline TAED with an average crystal diameter of 0.1 mm (determined by sieve analysis) was embedded in paraffin with a melting range of approximately 51 to 53 ° C. (cutable parrafin, Merck, Darmstadt). This was done in each case a part by weight of TAED mixed with a part by weight of paraffin at 55 ° C and after cooling to a temperature of 48 ° C screen granulated (mesh size 1 mm).

The granules thus obtained were introduced into a surfactant solution which (in g / 1)

0.2 sodium C ₁₂ . ₁₈ alkyl carboxylate

0.8 sodium C ₁₄ . ₁₆ alkyl benzene sulfonate

0.16 Nafr_um-Ci ₄ _ ₁₆ -fatty alcohol sulfate

0.03 C ₁₂ . ₁₈ fatty alcohol with 5 ethylene oxide units

0.16 sodium carbonate

1.06 zeolite A

0.29 sodium silicate

0.58 acrylic acid-maleic acid copolymer

0.02 optical brightener

0.08 phosphonate

0.02 NaOH (50%)

0.02 sodium sulfate

Contained 1.02 sodium perborate monohydrate.

The coated TAED granules were used in an amount of 1 g / 1 surfactant solution.

The amount of TAED released was then determined iodometrically at different temperatures using a peracetic acid titration.

The results are shown in Figures 1-3.

Figure 1 shows that at temperatures below the melting range of the coating material used, only a comparatively small proportion of TAED went into solution even after 10 minutes. Figure 2 shows that at a temperature above the melting range of the coating material, the trapped solid (TAED) dissolves to about 80% within one minute.

Figure 3 shows that the particle size of the solid particles used has a decisive influence on the release rate. If a finely ground product is used instead of the crystalline TAED, a tough, plastic body of paraffin and partially dissolved TAED is formed after the coating material has melted (without added additive), which hardly releases the TAED.

Claims

claims

1. A process for the production of coated solid particles, in which the solid particles are dispersed in the melt of a largely water-insoluble substance (coating) which is solid at room temperature and has a plastic solidification range, the dispersion is cooled, and at a temperature which is in the plastic solidification range Coating is granulated, the solid particles having a particle size of at least 0.05 mm, in particular at least 0.1 mm.

2. The method according to claim 1 or 2, characterized in that the covering has a melting range of 45 ° C to 75 ° C.

3. The method according to any one of the preceding claims, characterized in that the covering contains at least one paraffin wax with a melting range of 50 ° C to 55 ° C.

4. The method according to any one of the preceding claims, characterized in that the solid particles are selected from the group of enzymes, bleaching agents, bleach activators, surfactants and / or fragrances.

5. The method according to any one of the preceding claims, characterized in that TAED particles are used as solid particles.

6. The method according to any one of the preceding claims, characterized in that the solid particles are in crystalline form.

7. The method according to any one of the preceding claims, characterized in that the granulation takes place through a sieve with a mesh size of at most 2 mm.

8. Coated solid particles, obtainable by dispersing solid particles in the melt of a non-water-soluble substance (coating) which is solid at room temperature and which has a plastic solidification range, the dispersion is cooled and at a temperature which is in the plastic solidification range of the coating is granulated, the solid particles having a particle diameter of at least 0.05 mm, in particular at least 0.1 mm.

9. Coated solid particles according to claim 8, characterized in that they release less than 30% by weight of the solid particles in water at a temperature of up to 6 ° C below the start of the melting range of the coating after 10 minutes.

10. Use of coated solid particles according to one of claims 8 or 9, in detergents, in particular in detergents, detergents for hard surfaces, automatic dishwashing detergents or hand dishwashing detergents.