Additives for Polymer Dispersions
The Business Line Interface & Performance of Evonik positions itself as the market leader for surface active ingredients and performance additives.
Our product portfolio ranges from standard organic products to high performance products based on siloxane chemistry. These additives are capable to control and to adjust all surface related processes like defoaming, wetting, dispersing and emulsifying. We constantly develop and improve our product range backed by our research department and by having all necessary test facilities available in our development departments.
So we are able to understand and to solve emerging problems and to fulfil all our customer needs.
The dispersion is drawn down on a substrate with 50µm and a speed of 80mm/ s. A photo of the wet film is taken to evaluate the compatibility with the substrate.
A second indication for the wetting behavior of a dispersion on a substrate is given by draw dawn with 50µm and 80mm/s on siliconized substrate. A digital video of the wet film is taken for one minute. A picture out of this video after 10s is taken as result. It shows if a stable film can be build on siliconized substrate and how it looks like.
Adhesive coated stripes with a lenght of 15cm and a width of 2,5cm are prepared. They are stored for 4 hours in a climated room.
After that the stripe is applied on a float glass and stored again for 20min.
Than the stripe is peeled off the glass with a speed of 300mm/ min.
As result the average of the needed force to peel off the stripe is given in Newton and the appearence of glass and stripe is evaluated.
Adhesive coated stripes with a lenght of 17,5cm and a width of 2,5cm are prepared. They are stored for 4 hours in a climated room.
After that the stripe is applied on a small float glass with an area of 2,5x2,5cm and stored again for 20min.
Than the glass is arranged in a special device with an angle of 2°. A weight of 1000g is hooked into a triangular clamp at the end of the stripe.
The time which the stripe needs to slip off the glass disc is stopped.
As result this time is given in hours and the appearence of glass and stripe is evaluated.
Adhesive coated stripes with a lenght of 22,5cm and a width of 2,5cm are prepared. They are stored for 4 hours in a climated room.
After that the stripe is formed to a loop with the adhesive coated layer outwards.
The loop is arranged between two rolls and the coated side of the loop is brought in contact with a small glass disc. The float glass is directly pulled away with a speed of 300mm/ min.
As a result the maximum force needed to release the adhesive coated layer is given in Newton.
50 ml Liquid (including antifoam) are filled into a 100ml shaking-cylinder. The cylinder is shaken 10 seconds vigorously 30 times.
The foam height is noted down immediately and the foam collapse is measured over the time.
For this test one litre of surfactant solution is placed into a 2-litre graduated cylinder. A defined amount of prediluted antifoam is added.
Six litres of air per minute are passed through the sintered glass into the solution. The defined amount of diluted antifoam is added again by reaching the 2 litre mark and the time is noted down. The foam height is regularly noted down after a certain period of time. The test is stopped after 60 minutes and the total amount of antifoam is given as a measure of rating the efficiency.
50 ml Liquid (including antifoam) are filled into cylinder. Six litres of air per minute are passed through the sintered glass into the solution.
The foam height is noted down every 30s. After 5 minutes the test is stopped and the final foam height is noted down.
It is possible to observe the foam knock down for further 5 minutes without passing air through the solution.
100 g of the test dispersion (20 °C) including defoamer is poured into a beaker (6 cm diameter) and stirred with a turbine stirrer of 4 cm diameter at 2500 rpm, which runs at a spherical speed of 5.2 m/sec for 1 minute.
The emulsion is then immediately poured into a 50 ml measuring flask up to the calibration mark and the weight is determined. The weight depends on the amount of air which is included, due to the stirring and consequently it is a measure of the efficiency of the defoamer.