1. What is Uniprep AP 100
UniPrep AP 100 is a water-soluble liquid concentrate designed to promote adhesion of organic coatings on various metallic substrates, including steel, aluminum, and brass. It leaves a clear film that does not stain surfaces after air oven drying. Key features of UniPrep AP 100 include:
- High concentration
- Operation at ambient temperature
- Free of chromates, silicates, nitrites, and phosphates
- Dry-in-place coating, eliminating the need for post-application rinses
- Effective replacement for conventional iron phosphates in pre-paint applications
- Provides corrosion protection for steel surfaces
- Maintains substrate appearance, making it ideal for clear paint applications
The recommended equipment for using UniPrep AP 100 includes:
- Tanks: All steel, stainless steel, PVC, CPVC, polypropylene, Al or Zn components will be suitable.
- Heater / Cooling: Stainless steel, PTFE.
- Exhaust: Recommended (Eduction of steam) if the solution is heated.
- Agitation: In spray applications, no additional agitation is necessary. In immersion operation, air agitation or pump circulation of two tank turnovers/hour is recommended.
- Pump: Standard.
- Filtration: Not required, but recommended. Filter through a 25μm bag filter or equivalent.
- Racks, Jigs & Travelers: Standard.
- Compressed Air Blowoff: Optional - Utilization of a water-free, oil-free compressed air can aid solution draining and optimize pretreatment appearance (though this is rarely necessary with this product) .
The recommended processing sequence when using UniPrep AP 100 is as follows:
- Follow an effective cleaning cycle using UniPrep cleaners. Contact your local Atotech representative for recommendations.
- Rinse parts in cold water.
- Apply UniPrep AP 100 by either immersion or spray.
- Dry parts thoroughly.
- Apply paint or powder coating
The solution control and maintenance for UniPrep AP 100 involve several key steps:
pH Monitoring: The operating solutions are mildly alkaline. If the pH falls below 7.5, small amounts of UniPrep AP 100 concentrate should be added to bring the pH back to the optimal range of 7.5 – 9.0. The use of soda ash, caustic potash, or caustic soda for pH adjustment is not recommended .
Daily Analysis: UniPrep AP 100 should be analyzed daily to check its concentration, and appropriate additions of the concentrate should be made as necessary .
Water Quality: It is highly recommended to use reverse osmosis or deionized water for the make-up and replenishment of the UniPrep AP 100 solution. Using water with high levels of total dissolved solids (greater than 150) can lead to spotting or adhesion problems .
Solution Replacement: The UniPrep AP 100 solution should be replaced on a weekly basis, although the solution life can vary based on multiple factors such as cleaning, rinsing, and part configuration. The typical solution life is established individually at each account .
Drag-in Considerations: The solution maintenance can be affected if there is significant drag-out of the solution. Maintaining cleanliness prior to entering the solution and ensuring the final rinse before applying UniPrep AP 100 is well maintained will help extend the life of the solution .
By following these guidelines, the effectiveness and longevity of the UniPrep AP 100 solution can be maintained.
5.What recommendations are provided for wastewater treatment related to UniPrep AP 100?
The recommendations for wastewater treatment related to UniPrep AP 100 are as follows:
Wastewater from electroplating and painting shops must be treated according to local authority regulations, considering stated limit values and treatment methods.
The product contains complexing agents and cannot be sent to the general circulation of rinse water. Therefore, wastewater generated by this product must be treated separately.
Rinse water and concentrates should be diluted with rinse water in a ratio of at least 1:3 before being sent to the wastewater treatment plant.
Adjust the pH of the diluted solution to 6 – 8 and add sodium sulphide solution (10 – 15%). Add sodium sulphide until a significant potential jump is recognized during a potentiometric measurement or until lead acetate paper shows a brown color.
After a reaction time of 10 minutes, remove any weak sulphide excess with a small amount of iron(III) chloride solution (about 10%). The lead acetate paper should no longer be brown.
Adjust the pH to 9 using caustic soda or calcium hydroxide.
For better flocculation, add a flocculation agent (recommended: polyacrylamide/anionic with a mol mass of 4 – 6 million) and stir. Allow the precipitate to settle for better filtration.
After filtration is complete, the filtrate must not be mixed with metal ion-bearing waste streams.
These recommendations comply with the Regulation on requirements for the discharge of wastewater into water and were issued based on the limits provided in Annex 40 of the AbwV "Metal Handling and Metal Processing"
6. What is the procedure for determining the concentration of UniPrep AP 100 by titration?
The procedure for determining the concentration of UniPrep AP 100 by titration is as follows:
- Place 100.0 ml of the sample into a 250 ml Erlenmeyer flask.
- Add 100 ml of deionized (DI) water to the flask.
- Add 3 – 4 drops of bromothymol blue indicator solution (0.1 % w/w in alcohol).
- Titrate the mixture with 0.1 M hydrochloric acid standard solution until you reach a yellow endpoint.
After the titration, you can calculate the concentration of UniPrep AP 100 using the following formulas:
- The volume in ml of the 0.1 M hydrochloric acid standard solution used, multiplied by 0.53, gives the content of UniPrep AP 100 in ml/l.
- The volume in ml of the 0.1 M hydrochloric acid standard solution used, multiplied by 0.053, gives the content of UniPrep AP 100 in %
