What are the applications of Pellet binder in fish and shrimp feed
Compared with livestock and poultry feed, fish and shrimp feed has special requirements for processing and pelleting. It is generally required that fish feed pellets have a water resistance of ≥0.5 hours in water, and shrimp feed pellets have a water resistance of ≥2 hours in order to reduce loss and improve feed utilization.
To solve the problem of water resistance of aquatic pellet feed, two methods are generally adopted:
one is to increase raw materials with more starch content, such as secondary flour and wheat flour, to produce a certain cohesive force after gelatinization to improve the water resistance of pellets; the other is to increase the water resistance of pellets
. Add a special Pellet binder(or granulation aid) to the feed to make the granules have a certain degree of water resistance through the unique cohesive force.
The first method takes a long time, and it will cause greater damage to certain heat-sensitive substances in feed materials, such as vitamins, enzyme preparations, bacterial preparations, active factors, etc.; the second method will cause less damage to vitamins, enzyme preparations, etc. , and with less added amount, low cost and good effect, it has occupied the mainstream and is accepted by most feed manufacturers.
In the production of aquatic feed, polyurea formaldehyde binder is mainly used at present. This kind of binder is generally white homogeneous fine powder, easy to absorb moisture, and has a certain cohesive force at room temperature with a little water, but its real strong cohesive effect is after tempering and granulation.
The moisture brought by the steam during tempering makes the rubber powder fully infiltrate between the feed fine powder, and the polymer undergoes a chemical reaction under the high temperature of tempering and granulation. The cellulose, chitin, and lignin that are not easy to digest and absorb in the raw materials are covalently cross-linked with ether bonds, and form a highly branched lattice structure after cooling and solidification, thereby obtaining highly water-resistant pellet feed.
Whether you can get better granules is not only related to the quality of the binder, but also closely related to the conditioning time, moisture, temperature, granulation temperature, etc.
Here is a simple method to distinguish good or bad rubber powder:
First, take 1 part of rubber powder and 0.5 part of water (weight ratio) and mix it with a glass rod. If it is a high-quality rubber powder, the rubber powder is easy to dissolve and adjust, and it is transparent. It is easy to pull out the glue thread with a glass rod. .
Second, high-quality rubber powder can be dissolved in any proportion with water, while low-quality rubber powder is prone to precipitation or turbulence.
In order to produce qualified pellet feed with rubber powder, it is necessary to master the correct method of use:
(1) There must be enough time, temperature and water. Generally, the higher the tempering and pelleting temperature, the shorter the time to complete the bonding reaction; The lower the quality and granulation temperature, the longer the time to complete the binding reaction. Generally, it takes about 1 minute for rubber powder to complete cross-linking and curing at 100°C. For 1 minute, the rubber powder can be fully cross-linked and cured. In addition, sufficient water infiltration is also necessary for curing. The shorter the time required for complete curing of the rubber powder, the finer the material and the better the infiltration effect. If it is too thick, the effect will be poor. If the above three conditions are mastered well, only need to add 0.3% to 0.5% to achieve the desired effect.
(2) Do not store a large amount of rubber powder. Some feed factories store a large amount of raw materials at a time in winter for use in spring. In this way, since the storage time of the rubber powder is too long, self-crosslinking is prone to occur, denaturation and loss of viscosity. Since the rubber powder will slowly self-crosslink at room temperature. The higher the temperature, the faster the reaction. Generally, rubber powder stored for 6 months in the southern region is not suitable for reuse. Best out of the box.
(3) It should be stored in a dry and cool place. Rubber powder is easy to absorb moisture. After absorbing moisture, it will quickly solidify into blocks and lose its effectiveness and fluidity. Generally, moisture-proof packaging should be used, and the mouth of the packaging bag should be re-tightened when it cannot be used up at one time.