Method for producing an animal bedding

The present invention refers to a mixture containing different ingredients consisting of at least starch and plant fibres, intended to be placed on a support e.g. in the form of a litter tray for collecting urine and evacuation from domestic animals. The starch consists at least to some portion of special treated potato starch. It has been treated with water, heated to near 100 ⁰ C, mechanically treated, laid out in a thin layer, which has been dried during a temperature exceeding 100 ⁰ C for constituting a film, which has been milled down to a coarse powder or granulate.

Present mixtures of this type now on the market today are using different types of ingredients such as e.g. plant fibres, wood fibres, paper fibres and betonite in order to laid out on a litter tray for domestic animals for collecting urine and evacuation from these. Problems arise with many of these mixtures, such as that they are lacking a sufficiently good glue function, lump forming, lump strength and suction effect, which means that they do not absorb especially much moisture and too slowly and that they do not have enough capacity thereafter to enclose and encase the urine and the evacuation, which give rise to that strong smell that is emitted from these mixtures, which then will be disgusting and gluey, especially during removing of an used mixture. Gluey mixtures also get stuck to the paws and fur of the animals. The mixtures, when they are not used and are dry, give an inherent static electricity, which causes disagreeable for the domestic animal when parts of the mixture easily get stuck on the animal. Used mixture furthermore can easily get mouldy. Mixtures with bentonite are environment dangerous for kittens and not destructive in the nature and have a high volume weight, which make transports expensive and cannot be composted, which from a point of view of environment is not advantageous. Betonite can be burned but does not give an energy increase.

One object of the present invention is to decrease those drawbacks existing with today used mixtures, by that at least some part of the mixture contains starch and plant fibres, whereby the starch consists of potato starch, which

has been special treated with water, heated to near 100 ⁰ C, treated mechanically, laid out in a thin layer, which has been dried at a temperature exceeding 100 ⁰ C in constituting of a film, which has been milled down to a coarse powder or granulate.

Thanks to the invention a mixture has now been obtained containing different ingredients consisting of at least starch and plant fibres, which is intended to be used for domestic animals, preferably as "cat litter" for cats, to be laid out on a litter tray for collecting of urine and evacuation. The starch is according to the invention a special potato starch, here called special potato starch, produced by potato starch, which has been mixed up with water and heated up to near 100 ⁰ C and been treated mechanically and dried in a first drying process by heating to near about 100 ⁰ C, when it has been laid out in a thin layer on a support, which consists of a roller, when the special potato starch is in a porridge-like structure and then during a second drying process has been pressed out between two rollers in constituting of a film during a temperature of about 15O ⁰ C, which has been milled down to a coarse powder or granulate. The plant fibres has as a task that by capillary suction to suck up the liquid from the urine and the evacuation. The special potato starch has a much better capacity than other starch to glue together the plant fibres and suck up liquid also in a cold condition and therefore has the capacity to create sticky lumps of glued together plant fibres, which do not stick and which create a enclosing skin around the lumps, which decreases the stickiness and the smell. In a preferred embodiment example of the invention the potato fibre 25-35 weight percent of the plant fibres. The potato fibre is worked out by removal of the main part its fruit juice and the main part of the starch from potato. About 10- 16 weight percent of the mixture consists of the special potato starch. The potato fibre has in a dried condition an extreme good capacity to absorb the liquid with its empty cellular spaces, which sucks up near 6 times its own weight, which is much better than other plant fibres, which makes the lumps be dryer and less sticky. The mixture contains also about 35 -45 weight percent barley, which corresponds to 3 ,8 litres potato fibres per litre of barley. The barleys are crushed or milled to grains or granulates and are treated with water and are then dried. The starches also

contain a part of the plant fibres, which are smell neutral and are helping to take away the smell from the urine and the evacuation and to decrease the adherence of the mixture against paws and fur. The mixture also contains 7- 12 weight percent sodium chloride solution (NaCl) and 6- 10 weight percent sodium hydrogen carbonate (NaHCO3). The additive of the salt solution decreases the liquid activity to 0,6, which makes that the mixture does not raise a dust at the same time as the static electricity is lowered by that the conductivity of the mixture is increased, which in turn makes that the mixture does not get stuck on paws and fur. Furthermore a somewhat moistened mixture makes that moisture such as urine will be collected faster. Should only water be used the mixture should get mouldy. The sodium hydrogen carbonate is a salt, which stabilizes the acidity and which binds up ammonium ions, so that the mixture will not be evaporated and therefore decreases ammonium smell, which is strongly nasty smelling and irritating.

In the case the mixture does not have the correct percentage distribution of the included ingredients problems arise. Too little potato fibres causes decreased liquid absorption and that the volume weight will be too large. Too large amount causes bad lump forming and a bigger risk for the mixture to get stuck at paws and fur. A too great amount of milled barley decreases the solidity of the lumps and because of that the absorption capacity of the mixture of the liquid decreases and that the volume weight increases. Too little milled barley causes that the mixture is getting stuck in paws and fur. Too little special potato starch causes that the lumps easily get broken. Too much special potato starch can cause a raise of dust and that the excess is getting stuck in the paws and fur and that the lumps become gluey. The sodium hydrogen carbonate, which stabilizes the evacuation and the urine so that smell is minimized, also makes the strength of the lumps stronger. Too little is minimizing this effect. Too much does not give any further effect and can also cause the raise of dust and can also cause that the mixture creates a certain irritation.

The particle size in containing ingredients of the mixture is adapted for the obtaining of the best function and mixing method. The particle size in the

containing ingredients of the mixture vary between 30 my - 2,4 mm. The particle size of the potato fibre varies between 0,5 - 1 ,5 mm and the particle size of the milled barley is up to 2,4 mm and the sodium chloride (NaCl) has a particle size of up to 50 my. The granulate of the potato fibre has a particle size which is so great as the manufacturing method allows in order to minimize the risk that particles are getting stuck in paws and fur. The milled particle size of the barleys shall be so like each other as possible. The granulate of the special potato starch shall have a particle size, which makes that it will not create lumps when it is contacting water but it shall be so small that a so good distribution as possible is obtained of all particles. The sodium hydrogen carbonate shall be so fine as possible in order to get such a good distribution of all potato fibres and the milled barleys as possible.

The finished mixture is provided by that in different steps mix together the ingredients. In step 1 the potato fibres are mixed together with the milled barleys, whereupon in a step 2 the sodium chloride is mixed with water, which has been added in the form of a 20% salt solution. Finally in a step 3 the special potato starch in the form of the powder or granulate is mixed into the mixture and the sodium hydrogen carbonate (NaHCO3) in providing the finished mixture. Does it occur in another order the special potato starch take up the sodium chloride, so that the special potato starch looses its gluing qualities, when the urine is absorbed by the finished mixture. The milled barleys are also dried and heat treated in order to increase their liquid absorbing quality before they are mixed into the mixture.

The calculation of amount containing ingredients in the mixture can be made as is illustrated below:

Physical data:

Substance Particle diameter in mm Density kg/L

Average

Potato fibre 1 ,2 0, 1 8

Special potato starch 0, 18 0,5

Crushed or milled barley 2,0 0,9

Sodium bicarbonate 1 , 1

NaCl (20% solution) 1 ,2

The amount of milled barley and the amount of potato fibres has been determined by a number of experiments and tests with cat breeders with the purpose to minimize that amount of potato fibres which the cats carried with themselves in paws and fur in the way out from a cat box, while the cats easily should be able to be familiar with the mixture according to the invention. The particle size of the milled barleys corresponds to the size of the particles in earlier used mixtures, which are clay based. The purpose with the experiments were to keep as large amount as possible of the potato fibre with regard to its excellent absorbing quality. Thus, the optimal mixing in the mixture was determined after the experiments to:

3 ,8 L potato fibres by L crushed or milled barley.

Volume density potato fibres = 1/0, 18 = 5,56 L/kg. Share or amount of potato fibres/L = 3,8/5,56=0,684 L (L= litre)

In order to make the strength of the lumps better the special potato starch is added, which in contact with urine and evacuation obtains a gluing function. During contact with this moisture the granulate of the special potato starch is converted to a thin film having a surface, which is unfolded and encloses all potato fibre particles and the amount will be in ml/litre:

Abbreviation: F = potato fibre, S = Special potato starch, C = crushed or milled barley.

(Share F-litre/F-volume density x 10 ³ )/F-barley volume x F-particle area/S- particle area x S-particle volume. (Pi= about 3 , 14)

Thus:

(3,8 / 5,56 x 10 ³ )/ 4PiO,6 ³ /3 x 4 PiO, 6 ² / 4PiO, 09 ² x 4Pi0,09 ³ /3 = 1 04,6 ml/L

(minimum)

Crushed or milled barley: volume per litre = 0,684/3 ,8 = 0, 18. The share sodium bicarbonate has by tests been optimized to 3 volume per cent i.e. = 30 ml/litre. I litre of mixture shall also consist of:

Potato fibre 684 ml = 68,4%

Crushed or milled barley 180 ml = 18,0%

Sodium bicarbonate 30 ml = 3,0 %

Special potato starch =remaining= 106 HiI= 10,6% (Minimum = 104,6 (according to the above)

The mixture shall also consist of:

Crushed or milled barley 180 ml (minimum)

Potato fibre 684 ml

Starch 106 ml (minimum)

Sodium bicarbonate 30 ml

NaCl (20% dissolved in H2O).

Converting from volume per cent to weight per cent of in the mixture existing ingredients will be as follows:

Volume (ml) x density (mg/ml) = weight

Potato fibre: 0,684x0, 18 = 0, 123 mg

Crushed or milled barley: 0, 180x0,9 = 0, 162

Special potato starch: 0, 106x0,5 = 0,053

Sodium bicarbonate: 0,03x1 , 1 = 0,033

Sodium chloride as 20% solution:0, 09x0, 348= 0,04

Total weight= 0,41 1 mg

In percentage by weight:

Potato fibre: 0, 123/0,41 1 = 0,299(= 29,9%)

Crushed of milled barley: 0, 162/0,41 1 = 0,394(= 39,4%)

Special potato starch: 0,053/0,41 1 =0, 129(= 12,9%)

Sodium bicarbonate: 0,033/0,41 1 = 0,08 (= 8,0%)

Sodium chloride: 0,04/0,41 1 =0, 098(= 9,8%)

Thus the greatest advantages of the invention are that the mixture is non- polluting and based on renewable ingredients, and furthermore innocuous for animals and human being, hygienically manageable, has a good smell also after use, lump forming and enclosing, does not raise a dust, has a fast absorbing capacity, get fasten to a minimum on paws and fur, has a low weight, can be composted and burned. The ingredients are within reach in Sweden and because of that no long transports are required in order to have access of them.