EP0000160B1 - Process for the production of pellets from farinaceous fodder - Google Patents

Description

The invention relates to a method for producing feed pellets, d.s. Extrusions, by homogeneously mixing the feed with 0.1 to 2 percent by weight of a powdered urea-formaldehyde resin and then pressing.

The production of pellets, d.s. cylindrical strands or strands with differently shaped cross sections, e.g. 1 to 20 mm and e.g. 2 to 50 mm in length and briquettes made from floury feed, in particular compound feed, is a common method of imparting advantageous properties to the feed, such as preventing the components from segregating, lower storage and transport costs due to higher density, better dosing due to the good pourability and therefore particularly suitable in the case of non-manual feeding, lower feed losses, less sensitivity to changes due to air and light due to the lower specific surface area and better utilization of the feed by the animal due to chemical changes (digestion) of the feed during pressing.

• - Hohe Temperatur, die Nährstoffe und Vitamine schädigt. Hohe Temperatur entsteht jedoch durch die notwendige Dampfzugabe zum Mischfutter vor dem Pressen und durch die Reibungswärme beim Pressen durch die Matrizen;
• - Zu hoher Energieaufwand beim Pressen, da zu harte Preßlinge nicht gefressen werden. Außerdem tritt hoher Matrizenverschleiß, ein;
• - Staubbildung (Umweltbelästigung, technischer Aufwand zum Entfernen des Staubes aus den Arbeitsräumen);
• - Futtermittelverluste
• -zu leichter Abrieb des Preßlings, bewirkt durch zu niedrigen Energieaufwand und durch zu geringe Verdichtung beim Pressen;
• - Zu schlechte Bindung der Partikel, besonders bei groben Rohstoffen und bei hohem Fettgehalt, daher Brökeln des Preßlings.

However, the production of the pellets or compacts is a complicated technical process and the problems that arise have not yet been satisfactorily solved. The following parameters must be avoided when pressing:

• - High temperature that damages nutrients and vitamins. However, high temperature arises from the necessary addition of steam to the compound feed before pressing and from the frictional heat when pressing through the dies;
• - Excessive energy expenditure when pressing, as too hard compacts are not eaten. In addition, high die wear occurs;
• - Dust formation (environmental nuisance, technical effort to remove the dust from the work rooms);
• - feed losses
• too light abrasion of the compact, caused by too little energy consumption and too little compression during pressing;
• - Too bad binding of the particles, especially with coarse raw materials and with high fat content, therefore crumbling of the compact.

These disadvantages and problems, which occur in very different degrees, are very difficult to solve. Success depends on a number of known and unknown quantities that are not always recognizable. You try to influence these problems in different ways. This happens partly in terms of equipment, i.e. by varying the physical or technical parameters, partly through the personal skill of the workers and the press operator and partly through pressing aids.

• a) Schmierende oder gleitendmachende Wirkung, so daß sich das mehlige Futter leichter und mit weniger Energie pressen läßt.
• b) Bindewirkung, so daß die kleinen Teilchen besser zusammenbacken. Dabei soll der Preßling zwar abriebfest werden, aber nicht spröde. Wird er spröde und unelastisch, so bricht er beim Transport und bei der Lagerung.
• c) Der Geschmack soll nicht beeinträchtigt werden, da die Tiere das Futter sonst nicht annehmen.
• d) Das Preßhilfsmittel muß für Tier (und Mensch) physiologisch unbedenklich sein.
• e) Das Preßhilfsmittel soll mit allen Futterkomponenten verträglich sein.
• f) Es soll schon in geringer Konzentration wirksam sein.
• g) Es soll nicht mikrobiell angegriffen werden oder selbst mikrobielle Verunreinigungen in das Futter hineinbringen.
• h) Es soll thermisch stabil sein, um die beim Preßvorgang entstehende Wärme zu überstehen.

Pressing aids have a variety of effects and accordingly a number of different requirements are placed on them:

• a) Lubricating or lubricating effect, so that the floury forage can be pressed more easily and with less energy.
• b) binding effect, so that the small particles cake better. The compact should be abrasion-resistant, but not brittle. If it becomes brittle and inelastic, it breaks during transport and storage.
• c) The taste should not be affected, otherwise the animals will not accept the feed.
• d) The pressing aid must be physiologically harmless for animals (and humans).
• e) The pressing aid should be compatible with all feed components.
• f) It should be effective even in low concentrations.
• g) It should not be attacked microbially or even bring microbial contamination into the feed.
• h) It should be thermally stable in order to survive the heat generated during the pressing process.

• 1. Ligninsulfonat bis zu 30 g je kg Futter
• 2. Weißer Ton bis zu 30 g je kg Futter
• 3. Zelluloseäther
  • (= Carboxymethylcellulose) bis 3 g je kg
  • Futter.

Several pressing aids are now known which meet these requirements. The following are permitted under the Feed Act:

• 1. Lignin sulfonate up to 30 g per kg of feed
• 2. White clay up to 30 g per kg of feed
• 3. Cellulose ether
  • (= Carboxymethyl cellulose) up to 3 g per kg
  • Lining.

Lignin sulfonate is mainly used as a pressing aid in compound feed. It has the disadvantage that between 1.5 and 10% is required, depending on the recipe, and this is usually in connection with molasses. However, high molasses levels prohibit high temperatures because molasses caramelizes. Lignin sulfonate dilutes the feed due to the necessary relatively high concentration, thereby reducing the nutrient content. This can only be compensated for by using high-energy feed, which is more expensive. In addition, absorption by fiber such as lignin sulfonate is slowed down. Finally, lignin sulfonate always contains sulfur dioxide, which has a laxative effect.

White clay also has the disadvantage that it dilutes the animal feed and reduces the nutrient concentration. It also has a low baking effect. The result is a little abrasion-resistant compact. In terms of binding effect, white clay is still behind lignin sulfonate.

Cellulose ether, for example in the form of carboxymethyl cellulose, is only used in special foods because of the relatively high price. However, this substance also has the technical disadvantage of insufficiently binding high levels of fat in the feed.

From several patents e.g. US Pat. Nos. 3,989,846, 2,687,354, 3,873,733 and Czech Pat. No. 132,313 already knew the addition of urea formaldehyde resins to animal feed. In all of these patents, however, the task and the solution were different from the problem at hand, namely that pelleting of flour-shaped feedstuffs was achieved with small amounts of additives.

Therefore, the task remained to propose an advantageous process for the production of feed pellets, the aforementioned literature could not offer any solutions.

The object was achieved according to the invention by homogeneously mixing a powdered urea-formaldehyde resin which was prepared by spray drying a glue solution and which had a molar ratio of urea to formaldehyde of 1: 1.6 to 1: 2 and a free formaldehyde content of 1 to 4 percent by weight has, in amounts of 0.1 to 2 percent by weight, based on the feed, with flour-shaped feed and subsequent pressing into strands. The feed mixture is preferably heated beforehand, in particular with steam.

The pelleting process according to the invention is suitable for all floury individual feed and in particular compound feed.

Compound feeds are mixtures of vegetable, animal and synthetic organic and inorganic substances, e.g. Flour, soybean meal, fish meal, minerals such as monocalcium phosphate, dicalcium phosphate, trace elements in the form of magnesium oxide and copper sulfate and vitamins such as vitamin A acetate and vitamin E acetate.

Suitable powdered urea-formaldehyde resins are resins which are prepared in a manner known for glue production as an approximately 50 percent aqueous solution (viscosity: 80 to 120 mPa.sec at 20 ° C., molar ratio of urea to formaldehyde = 1: 1.95 to 1: 2.05), which is dried at 100 to 170 ° C to a product containing at most 2% by weight of water by spraying. A ratio of urea to formaldehyde of 1: 1.6 to 1: 2 is used. In contrast to the requirements for wood glue, this powder has a relatively high free formaldehyde content of 1 to 4 percent by weight, in particular 1.4 to 3 percent by weight and preferably 1.6 to 2.4 percent by weight. It has been shown that the higher the free formaldehyde content in the resin, the higher the abrasion resistance of the compacts. (The free formaldehyde content is determined by known methods, e.g. slurrying the powder in ethylene glycol and determining the free formaldehyde according to de Jong - De Jong et al, Rec. Trav. Chim. Pays-bas 71, 643 (1952).)

The free formaldehyde also has the further advantage that it is bound by the proteins, which are thus protected against premature breakdown in the rumen and reach the abomasum and / or small intestine without degradation. Formaldehyde also preserves the feed. The taste is not affected and the feed retains a pleasant smell.

With regard to the production of the resins, reference is made in detail to Ullmann Technical Encyclopedia Vol. 7, pages 406, 412-415 (4th edition 1976).

The urea-formaldehyde resins are mixed with the floury animal feed in amounts of 0.1 to 2 percent by weight. This has a clear effect at quantities above 0.1 percent by weight, which initially increases and only slightly increases at quantities above 2 percent by weight. The upper limit of the additional quantity is therefore limited primarily by economic reasons. Therefore, amounts of 0.15 to 1.5%, preferably amounts of 0.2 to 0.5% by weight are generally used.

The mixing of the urea-formaldehyde resins with the feedstuffs is expediently carried out in the usual mixers, e.g. Centrifugal mixers, screw mixers, twin screw mixers, vortex mixers, horizontal mixers, vertical mixers, batch mixers, continuous mixers until a homogeneous distribution is achieved. Then, after adding liquid and / or water vapor, the mixture obtained is pressed, depending on the pelleting method chosen, into pellets which are of the desired length, e.g. be cut between 2 and 50 mm. For the details of the presses and pelleting, see "Feed Manufacturing Technology" (American Feed manufactures Association, Feed Production Council) 1970, publisher: American feed manufactures Association Inc., 53 West Jackson Boulevard, Chicago Illinois 60604, pages 96 ff and 385 ff referenced.

With the method according to the invention, less energy is required when pressed, less abrasion, high elasticity and smooth surface of the compact and a protective effect against infestation by mold or bacteria.

• Beim Schweinefutter führt die Volumenvergrößerung dazu, daß sich die Schweine nicht mehr überfressen, da das erhöhte Volumen den Magen eher ausfüllt. Das Futter wird auch besser eingespeichelt, da es beim Kauen in kleinere Teile zerfällt. Beides wirkt sich durch längere Verweilzeit im Darm und bessere Ausnutzung, sowie besseren Voraufschluß durch den Speichel in einer besseren Verdauung aus. Die bessere Futterausnutzung bewirkt eine höhere Futterverwertung. Beim Fischfutter ist die Schwimmfähigkeit verbessert. Die Verunreinigung der Teiche wird dadurch erheblich geringer.

Furthermore, the pressings obtainable according to the invention have a certain porosity, so that the density is 20 to 25% less than without the addition of resin. Although this partially eliminates the advantage of lower packaging and transport volume, this property has a very beneficial effect on feeding:

• With pig feed, the increase in volume means that the pigs no longer overeat, as the increased volume fills the stomach. The food is also better stored as it breaks up into smaller parts when chewed. Both have a longer dwell time in the intestine and better utilization, as well as better pre-digestion by the saliva in a better digestion. The better feed utilization results in a higher feed utilization. The buoyancy of fish feed is improved. This significantly reduces the pollution of the ponds.

The advantageous properties of the pelletized feed by the addition of the urea formaldehyde condensate applied to the small amounts of the resins is surprising, although the adhesive effect of urea formaldehyde resins is well known for their use as wood glue. The sum of the properties mentioned in compound feed cannot be explained by experience with wood glue. High rye flour or starch paste additives (i.e. carbohydrates as in feed) have a lasting effect on the quality of the adhesive, the hardening takes place relatively slowly, which is why one should have expected that the compacts stick together; one should also have expected relatively brittle compacts.

According to the disclosure of DE-OS 1927971, urea-formaldehyde resins have also been added to animal feed. In contrast, the present invention differs significantly in the measures, the objective and the results. There is a particulate i.e. Non-floury feed is first treated with an amide, the feed is heated and dried, then a liquid, concentrated urea-formaldehyde condensate is applied and the feed is pelletized. In the only example in this regard, after treatment with urea, orange pulp is reacted with a condensate which has a molar ratio of formaldehyde to urea of 4.6: 1. The amount of condensate is 12.5 percent by weight, which is considerably higher than in the process according to the invention.

example 1 Pig feed alone

5000 kg of complete pork feed are pressed into pellets with the addition of 1% by weight of powdered urea-formaldehyde condensate. The pig feed has the following composition:

The pellets show a hardness of 10.44 kg / cm ² and an abrasion of 1.42%. The pressing performance is undiminished compared to the comparison test without urea-formaldehyde condensate.

The urea-formaldehyde condensate is produced as follows. An aqueous solution of urea and formaldehyde obtained in the usual way by acid condensation, in the present case as a urea-formaldehyde condensation product with a solids content of 50%, is evaporated to a powder at 100 to 170 ° C. in a spray dryer. The molar ratio of urea to formaldehyde is 1 to 1.9. The water content is 3% and decreases to 2% after 1 week. The bulk weight is 0.7 kg / i. The grain size distribution is as follows:

a) Comparison test

5000 kg of pig feed complete feed mixture of the above composition are pressed without the addition of urea-formaldehyde condensate. The pellets have a hardness of only 8.34 kg / cm ² and an abrasion of 3.40% corresponding to 2.4 times the pellets produced according to the invention.

• Die Pellets werden in einem Drehkasten gefüllt, der mit 50 Umdrehungen pro Minute 500 Umdrehungen ausführt. Anschließend werden die Pellets gesiebt. Der Siebdurchgang, das Material mit einem kleineren Durchmesser als der eines ganzen Pellets, wird als Abrieb bezeichnet.

The abrasion is determined as follows:

• The pellets are filled in a rotary box which executes 500 revolutions per minute at 50 revolutions per minute. The pellets are then sieved. The sieve passage, the material with a smaller diameter than that of an entire pellet is called abrasion.

Example 2 Carp feed

5000 kg of carp feed are pressed into pellets with the addition of 1% powdered urea-formaldehyde condensate of the same composition as described in Example 1. The carp feed has the following composition:

The pellets have a hardness of 10.1 kg / cm ² and an abrasion of 1.51%. The pellets were still in shape after 12 hours of remaining under water and are not dissolved. This is surprising since urea-formaldehyde glue is water-soluble and a gluing effect at this concentration is unknown.

a) Comparative experiment

5000 kg carp feed of the above composition are pressed without the addition of urea-formaldehyde condensate. The compacts have a hardness of only 8.2 kg / cm ² and have 3.42% abrasion. They dissolve completely in the water after 4 minutes. The components are distributed in the fish basin.

Example 3 Complete carp feed

werden mit 5 kg pulverförmigem Formaldehyd- Kondensat (= 0,5%) (hergestellt gemäß Beispiel 1) gemischt und zu Pellets gepreßt. Die Pellets bleiben 3 Tage im Wasser stabil und zerfallen dann. 10 Karpfen, deren Gewicht zu Versuchsbeginn zwischen 10 und 20 g liegt, werden 61 Tage mit dieser Mischung gefüttert. Als Gefäß dient ein Versuchsaquarium mit den Abmessungen 60 x 30 cm, Höhe 40 cm. Das Aquarium enthält 60 l chlorfreies Leitungswasser. Das Wasser wird im Kreislauf geführt, wobei Kohlefilter eingeschaltet sind. Die Temperatur beträgt 20 bis 22°G. Die 10 Karpfen erhalten pro Tag 3 g des Futters. Die Gewichtszunahme pro Tier und Tag beträgt 0,46 g.1000 kg carp feed of the composition

are mixed with 5 kg of powdered formaldehyde condensate (= 0.5%) (prepared according to Example 1) and pressed into pellets. The pellets remain stable in the water for 3 days and then disintegrate. 10 carp, the weight of which is between 10 and 20 g at the start of the experiment, are fed with this mixture for 61 days. A test aquarium with the dimensions 60 x 30 cm, height 40 cm serves as the vessel. The aquarium contains 60 l of chlorine-free tap water. The water is circulated with carbon filters switched on. The temperature is 20 to 22 ° G. The 10 carps receive 3 g of the feed per day. The weight gain per animal and day is 0.46 g.

A test carried out analogously, but without the addition of formaldehyde-urea condensate, gives pellets which remain stable for only 1 to 2 days. The weight gain per animal and taq is 0.28 g.

A test carried out analogously, but with a 2% addition of formaldehyde-urea condensate, gives pellets which remain stable for 3 to 10 days. The weight gain is 0.31 g per animal and day.

Example 4 Pig feed alone

werden mit 0,25% Formaldehyd-Harnstoff-Kon-densatpulver gemischt und zu Pellets gepreßt. Die Temperatur am Presseneingang beträgt 74°C, am Pressenausgang 80°C, Kühlertemperatur 16°C. Der Wassergehalt der Mischung nach dem Kühlen (infolge Dampfzusatzes) beträgt 14,6%. Der Abrieb wurde zu 4% gefunden.4000 g of pork feed of the composition

are mixed with 0.25% formaldehyde-urea condensate powder and pressed into pellets. The temperature at the press inlet is 74 ° C, at the press outlet 80 ° C, cooler temperature 16 ° C. The water content of the mixture after cooling (due to the addition of steam) is 14.6%. 4% of the abrasion was found.

Comparison test

In an analogous approach, as much lignin sulfonate is added (by trial and error) until the same abrasion value is reached. The lignin sulfonate content is 1.6%, i.e. 6 times the value for the formaldehyde-urea condensate.

Claims (2)

1. A process for the manufacture of pellets of animal feeds and urea-formaldehyde resins by dry mixing and pelletizing, characterized in that a pulverulent urea-formaldehyde resin which has been prepared by spray-drying a glue solution and which has a molar ratio of urea to formaldehyde of from 1:1.6 to 1:2 and a content of free formaldehyde of 1 to 4% by weight, based on the animal feed, is homogeneously mixed with the mealy animal feed and then pelletized.

2. A process as claimed in claim 1, characterized in that 0.15 to 1.5% by weight of the urea-formaldehyde resin is added.