WO2006042617A2

WO2006042617A2 - Process for producing a bedding material which absorbs animal waste, in particular liquid animal waste, for domestic animals

Info

Publication number: WO2006042617A2
Application number: PCT/EP2005/010359
Authority: WO
Inventors: Dietrich Koch; Franz Josef Gassmann; Annette Krause
Original assignee: S & B Industrial Minerals Gmbh
Priority date: 2004-10-14
Filing date: 2005-09-24
Publication date: 2006-04-27
Also published as: DE102004050058A1; WO2006042617A3

Abstract

A process is disclosed for producing a bedding material which absorbs animal waste, in particular liquid animal waste. According to this process, grains of a porous granulate with an apparent density of less than 900 g/l are mixed with an absorbent material, if required with admixture of liquid, then dried, so that the resulting two-layered grains have a core made of the porous granulate and a sheath made of the absorbent material, the thickness of the coating made of absorbent material ranging from about 0.1 to 3 mm.

Description

Process for the preparation of a particular liquid animal waste absorbing scattering agent for pets

Description:

The invention relates to a process for the preparation of a particular liquid animal waste absorbing gritting agent for pets.

Such a method has become known, for example, from US Pat. No. 4,591,581. Here, the procedure is that individual mineral grains are dried with a grain size below 2 mm substantially and then mixed with water. Subsequently, this mixture is compacted and crushed into individual particles of desired size. As mineral starting materials, clay minerals are used.

In addition, it is generally known to use water-swellable sodium bentonite clay in conjunction with an animal-waste absorbing composition, as described in EP 0 378 421 B1. In doing so, liquid animal waste can be selectively removed from a garbage can because it produces an agglomerated mass that includes the absorbent composition and liquid animal waste. This agglomerated mass is of sufficient size and coherence force to be removed from the waste box.

In the context of DE 43 28 285 C2 an animal litter, in particular cat litter, is described, in which a moisture-absorbing organic material is equipped as a particle core with a particle shell which has a mineral material. The proportion of mineral material in the Particles is between 5 and 25 wt .-%. The moisture-absorbing organic material as the particle core is mostly cellulose.

Detergent granules have become known from DE 690 10 535 T2, in which the granule surface is covered with a layer surrounding an organofilm clay material. The organofile clay material includes organofile smectite clay and organofile kaolin clay.

In the context of DE 198 43 887 A1, a hygiene granulate is presented, which is produced on the basis of calcium silicate hydrate and bentonite. In this case, pelletized granules are used with a two-layer structure, wherein the core predominantly calcium silicate hydrate and the shell has a mixture of finely divided swellable clay mineral and finely divided calcium silicate hydrate.

The known procedures have basically proven, as far as the liquid absorption capacity of the clay mineral used and its agglomeration is concerned in order to be able to remove individual lumps from an associated waste box. However, the marketable products are relatively heavy because their bulk density is in the range of about 1 kg / l. Insofar as improvements have already been tried here in the context of DE 198 43 887 A1, the absorption capacity can not be completely convincing, because the jacket in the two-layered grain is produced from the calcium silicate hydrate dust and a certain proportion of bentonite, as described. About 50% by weight of bentonite and 50% by weight of the dust are used. There is no information about the moisture absorption capacity.

A similar two-layer structure describes the DE 43 12 279 C2. Here, there is provided a fluid adsorption and absorption agent equipped with a granular porous carrier material whose surface is covered by a clay mineral component. As a result, overall bulk weights of less than 600 g / l can be achieved. However, information on the layer thickness of the surface coating is missing. This also applies to the light, clumping small animal litter known from EP 1 092 346 A1. This refers back to a share A with shredded waste paper, water and waste bentonite and a proportion B of a swellable bentonite for wrapping back.

The invention is based on the technical problem of specifying a method for the production of a scattering agent for pets, with the aid of which the scattering agent can be produced inexpensively and has the same positive properties as previous scattering agents. In addition, the handling of the spreading agent should be improved by reducing the weight as much as possible.

To solve this technical problem, the invention provides a process for the preparation of a particular liquid animal waste absorbie¬-generating gritting agent for pets, after which grains of pore granules are mixed with a bulk density below 900 g / l with an absorbent optionally with the addition of liquid and then dried so that the thus produced two-layered grains having a core of the pore granules and a jacket of the absorbent have a sorbent coating with a layer thickness of about 0.1 mm to about 3 mm.

With granules of pores, the invention granular materials which are present in a grain size of usually about 0.1 to 10 mm, in particular about 0.5 to 5 mm and preferably about 0.5 to 2 mm and find Ver¬ use as starting material , In addition, the pore granules are characterized by the required bulk density of below 900 g / l. In addition, the granular pore is characterized by an open-pored surface. In other words, the surface which is decisive for the absorption of liquid is a multiple of a spherical surface of the mostly spherical grains, for example may be 10 or 100 times larger. Bulk weights of the pore granules in the range between 400 g / l and 700 g / l, in particular between 500 g / l and 600 g / l have proven particularly useful. Very particularly preferred is a range of bulk density for the pore granules between 540 g / l and 580 g / l. By these design rules, the generic scattering agent is predestined for use for receiving particular liquid animal waste. Of course, a use as an ad / absorption agent for the intake of environmentally relevant liquids, spielsweise in accidents conceivable and is covered.

In any case, it has been found that grain sizes of about 2 to 3 mm with a bulk density of between 500 g / l and 700 g / l are particularly favorable for use as a bedding product for pets. Because this avoids that the pet in question, usually a cat, unnecessarily develops dust in a litter box or carries the litter out of the litter box.

As pore granules, for example, foam glass granules can be used, which is made of waste glass, synthetic or mineral glass, as described for example in DE 39 41 732 C2 or WO 00/61512 A1. However, because of the low bulk density of such foam glass granules, this is usually not the case, but advantageously uses pore silicates, in particular calcium silicates or calcium hydrosilicates. Examples are Foshagit, Hillebrandit, Nekoit, Okerit and Riversideit and Tobermorit. Calcium (hydro) silicates are of particular importance in cement and building material mineralogy, are therefore inexpensive and present in large quantities, so that the costs for the pore granules or the core of the two-layered grain according to the invention are less than those of the costs For example, this site would resort to a bentonite core of the same size. That is, such pore granules or pore silicates are preferably available. It may be resorted to synthetic pore silicates, such as synthetic calcium silicate zurück¬. But it can also be natural quartz sand with the addition of Lime and a pore-forming agent processed to an open-pore dough, then broken and filtered.

Overall, the pore granulate or pore silicate may have a residual water content of less than 35% by weight. That depends on the final drying process. In order to improve the abrasion resistance of the grains of the pore granules during and / or after drying, it is possible to spray them with the aid of a binder, for example a bentonite suspension. However, if the abrasion resistance of the absorbent coating is sufficient, it may of course be dispensed with such a spraying process. This also applies to a final Siebvor¬ gang, with the aid of which the coated grains of pore granules can be sieved after drying and possibly spraying. Because even this classification process is to be regarded as an option.

In the context of the invention, therefore, no (more) clay mineral is used as the main constituent of the scattering agent, but instead, granules of the pore granulate or pore silicate are used, which are then coated with the actual absorption medium. The absorbent coating is present in a layer thickness of about 0.1 to about 3 mm, so that the use of material for the absorbent is kept to a minimum. Indeed, clay mineral-based absorbents, especially three-layer clay minerals, have been found to be particularly beneficial. For such clay minerals have an extremely pronounced swelling capacity, which is able to absorb the liquid animal waste (or other, for example, environmentally harmful liquid substances). At the same time, the grains according to the invention agglomerate into lumps which are easy to handle and which can be removed from an associated litter box without problems and are predestined for disposal in the toilet, for example. The properties are thus comparable to those provided by conventional spreading materials. In the clay mineral usually montmorillonite is used, which is the main component of commercially available bentonites. In particular, the invention recommends the use of a calcium bentonite, a natural sodium bentonite or a technically activated sodium bentonite. The absorbent or the clay mineral or bentonite may additionally be accompanied by an optical brightener. This optical brightener is preferably titanium dioxide, which is also used brighter in papermaking. The binder for increasing the abrasion resistance of the absorbent coating is usually methyl cellulose or water glass.

Overall, it has been found that the absorbed liquid is stored primarily in the absorbent coating, which is able to do so because of their high absorption capacity. At the same time, however, there is also the possibility that the core of the pore granules is available as a result of its open-pore structure for effective fluid absorption. That is, the liquid may initially be taken up by the jacket and then passed on to the core. Of course, only a liquid absorption in the jacket is possible.

As a result, a novel bedding agent for pets is provided, which is capable of absorbing liquid animal waste in particular. In this context, the scattering agent described convinces by improved handling in comparison to known scattering agents, wherein by resorting to pore granules as main component with a weight fraction of usually more than 50 wt .-%, in particular more than 60 wt .-%, preferably more than 70 wt .-% of the finished scattering agent or the End¬ product a special cost reduction compared to conventional scattering agents based on pure clay minerals is achieved. In comparison with these clay mineral-based spreading materials, the bulk density is reduced by about 50%, so that, moreover, transport to the customer and handling by the customer - in addition to the described cost advantages - are improved. All this is finally supported by the fact that advantageous the scattering agent according to the invention is optically virtually indistinguishable from previous embodiments. On the one hand, the absorber coating on the basis of a clay mineral and, on the other hand, the optional addition of a brightener contribute to the absorbent.

Overall, water uptake rates well above 100% by weight are achieved which even exceed the values given in US Pat. No. 4,591,581 for conventional dispersants. Because the water absorption (according to Westinghouse) is in the scattering agent according to the invention over 300 wt .-%, in particular even over 400 wt .-%.

The teaching of the invention thus makes it clear that the previous clay mineral or bentonite-based spreading agents have used almost exclusively the outer layers of the respective grain for liquid absorption, whereas the inner core has mostly taken up no more liquid. In fact, it has been found within the scope of the invention that the absorbed liquid has penetrated into the individual grains up to a maximum of 3 mm from the surface, at the same time the desired lump formation has taken place. As a result, it is sufficient according to the invention to design the two-layer grain structure in such a way that work is carried out with an absorbent coating whose layer thickness is at most 3 mm.

In most cases, even an absorbent coating with a layer thickness of 2 mm has proven sufficient. Because the fact that the liquid penetrates into this absorbent coating, the outer layer increasingly swells and favors the described agglomeration with neighboring grains. At the same time access to the kernel is made increasingly difficult by the swollen outer layer.

The core of the two-layered grain thus hardly contributes to fluid intake, although this is of course still possible. Because the pore granules used there can provide a specific surface area of up to 1 m ² / g, whereas the specific surface area of the absorbent granules coating mostly above 200 m ² / g, in particular more than 300 m ² / g is settled. As usual, the surface related to a unit of weight can be determined, for example, by a complete coverage of all surfaces with polar organic molecules and, in the case of clay components with intracrystalline swelling capability, comprises both external and internal surfaces.

In any case, the present innovation uses the knowledge that when using the described grains as liquid animal waste absorbing litter virtually only a smaller outer layer is used for fluid intake. As a result, the inner core may consist of a lightweight material, namely the pore granules, which at best supports the liquid absorption, but primarily does not record this responsibility. By contrast, the actual liquid absorption takes place in the absorbent coating with the specified layer thickness of about 0.1 to 3 mm. The pore granules in the core - as well as the absorbent coating - does not tend to react with the animal waste and incidentally is harmless to health, so that nothing is against the use as a scattering agent ent¬. All this is achieved with a substantially halved bulk density in comparison to conventional Klumpstreus and with the same ability to clumping or agglomeration. - As a material for the core, the invention preferably recommends pore silicate, especially calcium silicate, although of course other open-pore materials such. B. Schluffen use can be found.

Example:

First, pore granules are provided with a grain size of 0.1 to about 3 mm grain diameter. The bulk density is between 500 g / l and 600 g / l. For the production, the aforementioned applies.

The absorbent coating can be applied to the respective grain of the pore granules in basically two ways. In a first variant, the individual grains are mixed with water or another saturated liquid and placed in a mixer (eg Lödige or Eirich mixers). An Eirich mixer is known to have a granulating plate equipped with a high speed stirrer and stirrer blades. The stirrer blades rotate at a slower speed than the granulating disc, in a direction opposite to its direction of rotation.

Following the mixing of the grains with water or the other liquid, the absorbent or a bentonite is added as a powder (or in addition as a binder), wherein optionally the already described optical brightener, for. As titanium dioxide, is contained in the powder. As part of the incipient mixing process, the individual grains of pore granules are equipped with the desired absorbent coating. As soon as the absorbent has completely enveloped the respective grains with a layer thickness of about 0.1 to 2 mm and a free-flowing granulate with a grain size between about 0.3 mm and 7 mm has formed, the mixing process is ended.

Alternatively, the grains of the pore granules can also be added to a mixer in a dry state, to which an aqueous slurry of the absorbent or of the white concreteite, to which an optical brightener has optionally been added, is added to this dry mixture. As already described above, the mixing process is ended when a flowable granulate has formed, taking into account the absorption coating of about 0.1 to 2 mm. The thickness of the absorbent coating is detected continuously by ultrasound or by resorting to other thickness measuring methods on test beads, so that the mixing process can be stopped accurately.

In any case, after the mixing process described above excess water is removed by the still moist granules is dusted using a powdered mixture of the absorbent (white bentonite), an optical brightener and optionally a binder. Thereafter, a new mixing for about 1 to 2 minutes, until the granules have no more agglomerates.

In the next step, the granules are then dried in a hot-air dryer to a residual moisture content of 3 to 10% by weight, with the still-hot granules then being treated with an aqueous solution of a binder (eg methylene chloride) to improve the abrasion resistance of the absorbent coating ¬ cellulose or water glass) is sprayed.

Finally, the dried granules are sieved on a sieve in the desired grain fraction.

The following characteristic values for the novel scattering agent result:

Bulk density: 445 g / l;

Grain distribution: 4.0 - 3.15 mm: 0.9%

3.15 - 2.0 mm: 40.1%

2.0 - 1, 0 mm: 51, 1%

0.5-1.0 mm: 7.9% <0.5 mm: 0%

Water absorption to Westinghouse: 405% by weight;

Club diameter approx. 5 to 10 cm.

Claims

claims:

1. A process for the preparation of a particular liquid animal waste absorbie¬ ing grit, after which grains of pore granules are mixed with a bulk density below 900 g / l with an absorbent optionally with liquid keitsabeabe and then dried, so that the thus produced two-layer Grains with a core of the pore granules and a jacket of the absorbent have an absorbent coating with a layer thickness of about 0.1 to 3 mm.

2. The method according to claim 1, characterized in that the layer thickness of the absorbent coating about 0.1 to 2 mm, in particular about 0.1 to 1 mm.

3. The method according to claim 1 or 2, characterized in that the pore granules in a grain size of about 0.1 to 10 mm, in particular about 0.5 to 5 mm, preferably about 0.5 to 2 mm, as the starting material Use finds.

4. The method according to any one of claims 1 to 3, characterized in that the bulk density of the pore granules in the range between 400 g / l and 700 g / l, in particular between 500 g / l and 600 g / l, preferably in the range between 540 g / l to 580 g / l, is settled.

5. The method according to any one of claims 1 to 4, characterized in that as pore granules poresilicate, in particular calcium silicate, is used.

6. The method according to any one of claims 1 to 5, characterized in that a clay mineral, in particular three-layer clay mineral is used as the absorbent.

7. The method according to claim 6, characterized in that it is the clay mineral to montmorillonite as the main constituent of commercial bentonites.

8. The method according to any one of claims 1 to 7, characterized in that the absorbent is added to an optical brightener.

9. Scattering agent for the absorption of particular liquid animal waste, gekenn¬ characterized by a pore granules having a bulk density below 900 g / l, the individual grains have an absorbent coating with a layer density of about 0.1 mm to 3 mm.

10. Use of the scattering agent according to claim 10 as klumpfähiges animal litter in a litter box.