Amphoteric Filler for Low pH Applications
GREIBOTAN AF7
GREIBOTAN AF-7 is an amphoteric filling agent based on an acrylic copolymer sodium salt water solution, specifically developed for application at low pH values. Its amphoteric character gives it pH-responsive charge behaviour, allowing it to act cationically in the acidic conditions of pickling and chrome tanning, where it develops a strong affinity for the collagen fibre structure and achieves deep and even penetration throughout the full hide cross-section.
GREIBOTAN AF-7 is developed for loosely structured and empty hides and skins, where it improves grain tightness and effectively levels out fullness differences between the dense and loose areas of the hide, such as back, belly, and flank zones, resulting in a more uniform and commercially consistent leather.
A particularly significant benefit of GREIBOTAN AF-7 is its ability to considerably improve chrome exhaustion and chrome fixation during tanning. The interaction of the amphoteric polymer with chrome centres in the collagen network promotes more uniform distribution and higher uptake of chromium, enabling a chrome saving up to 20%, with associated cost and environmental benefits.
Key Benefits
Characteristics
| Base | Acrylic copolymer based on a sodium-salt water solution |
| Appearance | White liquid |
| Active substances | Approx. 28 % |
| pH of a 10 % solution | 4.5 – 6.5 |
| Charge | Anionic |
| Resistance to electrolyte | Very good to acid, salt and alkali |
Properties
Application Examples
GREIBOTAN AF-7 is used at two distinct dosage levels depending on the application stage and the specific requirements of the process.
For retanning and filling of loosely structured hides, 2 to 3% on shaved weight is recommended, ensuring thorough and even filling of the interfibrillar spaces throughout the hide structure and effective levelling of fullness differences between dense and loosely fibred areas.
In chrome tannage, where the primary objective is to improve chrome exhaustion and fixation, 0.5 to 1.0% on pelt weight is applied. At this dosage, GREIBOTAN AF-7 promotes the uniform distribution of chromium throughout the collagen matrix, increases the rate of chrome uptake, and enables a reduction in chrome consumption up to 20% without compromising the tanning result.
Legal Information
GREIBOTAN AF-7 has a shelf life of approximately one year and is resistant to frost. Should the product freeze, it can be fully restored by warming to approximately 20°C and stirring to homogenise.
The information contained in this publication is based on our current knowledge and practical experience. It does not relieve the user of the responsibility to conduct their own tests and assessments, particularly with regard to any influences that may arise during the processing and application of our products. No legally binding guarantee of specific properties or suitability for a particular purpose can be inferred from the information provided herein. It is the sole responsibility of the recipient to observe any applicable intellectual property rights as well as all relevant laws and regulations.