What properties of phenolic resin anti-rust coatings must be inspected? What are the indicators?

Phenolic resin is insoluble in water and high temperature resistant, and is used in some high temperature fields, such as foundry industry, refractory materials, etc. Today I will introduce what conditions should be met in the performance testing of phenolic resin antirust coatings under the provisions of GB/T 25252-2010.

Item detection

1. State in the container: First, we open the container and stir with a spatula or a stir bar. If the sample is in a uniform state without hard lumps after being stirred and mixed, it is regarded as up to standard.

2. Outflow time: use ISO6 cup, if the outflow time of red lead sample is ≥35s, iron red sample is ≥45s, zinc yellow sample is ≥55s, mica iron oxide sample is ≥40s, other samples are ≥45s , then the standard is met.

3. Fineness: If the fineness of red lead sample is ≤60 μm, that of iron red sample is ≤55 μm, that of zinc yellow sample is ≤50 μm, and that of other samples is ≤55 μm, it is regarded as up to the standard.

4. Hiding power: If the hiding power of the iron red sample needs to be ≤55g/m²; if the hiding power of the zinc yellow sample needs to be ≤180g/m², it is regarded as up to standard. The rest of the samples shall be determined by the testing parties according to actual needs.

5. Workability: If the sample has no obvious resistance, wire drawing, air bubbles, sagging, etc. during the application process, it can be rated as "no barriers to application".

6. Drying time: the sample needs to be ≤24 hours for solid drying and ≤5 hours for surface drying to be considered up to the standard.

7. Appearance of paint film: use visual inspection method to observe whether there are orange peel, wrinkles, stains, particles, shrinkage cavities and other phenomena on the surface of the model under natural sunlight. If not, it can be rated as "normal".

8. Impact resistance: If the test result is that the sample is 50cm, it is considered up to the standard.

9. Hardness: If the red lead sample is ≥0.20, the iron red sample is ≥0.20, the zinc yellow sample is ≥0.20, the micaceous iron oxide sample is ≥0.30, and other samples are ≥0.20, it is regarded as up to the standard.

10. The sample adhesion must be ≤ 2 grades to be considered up to the standard.

11. Skinning property: Place the sample in an environment with a temperature of (23±2)°C and a relative humidity of (50±5)% and let it stand for 48 hours. Rated as "no skinning".

12. Salt water resistance: Prepare three copies of each sample and soak them in 3% NaCI solution. Among them, red lead samples were soaked for 120 hours, iron red samples were soaked for 48 hours, zinc yellow samples were soaked for 168 hours, mica iron oxide samples were soaked for 120 hours, and other samples were soaked for 48 hours. If the test results show that at least 2 of the 3 test panels have no coating film pathological phenomena such as blistering, cracking, peeling, and obvious discoloration, it is rated as "no abnormality".