1. Firstly, clean the mold with detergent, and dry it by a piece of cloth or an air gun and then coat the mold with a layer of release agent.
2. Generally, the ratio of pad printing silicone rubber and the silicone oil depends on the size of pattern which customer needs to print. The larger the pattern is, the softer the printing pad should be, and more silicone oil needs to add.
Contrarily, if a silicone pad with high hardness needed, silicone oil should be added less or none. Generally. the hardness of the printing pad is 15A~-25 A. If too much silicone oil added in the silicone rubber, the printing pad will be too soft, and this will limit the printing times. The silicone
oil will destroy the molecular chain of the silicone rubber, no matter how supreme quality the silicone rubber is.
And therefore, the printing pad will be abrasion intolerant and solvent intolerant and easy ageing.
3. General mixing proportion is as follows: add 30g silicone oil into 100g silicone then hardness of 20A printing pad we get, which is suitable for the pad printing for alloy car and other products with small patterns and contact areas. If a big contact surface or a soft silicone pad needed, the
mixing proportion between the silicone and the silicone oil can be 100:30-100:50. But please note that the more silicone oil added, the softer the silicone pad will be, which will also reduce printing times, abrasion resistance and solvent resistance. Therefore, cost increase and material
waste will occur.
4. Relation between the amount of the curing agent added and the chemical reaction of the silicone is as follows:
Mix 100g silicone and 50g silicone oil sufficiently and evenly.
Then add the curing agent which is 2%-3% of the total weight of the silicone and the silicone oil, keep stirring for 2-3 minutes, and then vacuuming to remove the air bubbles. It is better to finish vacuuming within 10 minutes. If it takes too long, it may cause fast curing and affect the quality
of the printing pad