Pad printing silica gel is a two-component compound. The vulcanization reaction is carried out at room temperature. The base material is composed of double-hydroxyl-terminated polysiloxane, reinforcing agent, etc.;
The two groups of compounds cross-link in the presence of catalysts to form flexible elastomers. The vulcanized pad printing adhesive has the following characteristics:
1. Room temperature vulcanization, no heat, good dimensional stability and bright gloss.
2. It has good changing properties and mold release properties, and at the same time, it has good fluidity.
3. It has good elasticity and high tear resistance. It is suitable for various applications without deformation, and it is easy to demould.
4. Easy to operate, easy to use, and the curing cycle can be adjusted within a certain range.
Second, the production process
1. First clean the tools such as plastic head molds, mixing buckets, and mixing sticks with detergents (detergent, rubbing copper water, etc.) (different types of molds use different detergents, Do not use highly corrosive solvents, such as Tianna water, net washing water, etc.). Then wipe it thoroughly, without any foreign objects and stains. Then apply a layer of release agent on the mold: such as Vaseline, detergent, etc. (Some molds do not need to be coated with release agent).
2. Calculate the pad printing silicone/pad printing paste and silicone oil according to the volume of the mold (adding silicone oil can properly adjust the hardness of the rubber head. If the amount is too much, the wear resistance of the rubber head will be poor.), mix and stir evenly. Then let stand for 10 minutes or vacuum.
3. Add a certain weight of curing agent according to the total weight of the mortar and silicone oil after stirring, and stir again quickly and evenly for 3-5 minutes. Afterwards, if there are conditions, vacuum debubbling can be performed immediately, which is called forced debubbling method; if vacuum debubbling is not performed, it is called waiting for natural defoaming method.
4. The mixture after vacuum debubbling or standing for debubbling. Slowly pour into the mold from the edge of the mold. Do not pour a large amount into the center of the mold, which will increase the amount of air bubbles and reduce the service life of the rubber head. 5. After the vacuumed mixture is poured into the mold, it can be covered with wood chips; the mixture with natural foaming is poured into the mold and left for about 30 minutes, and then covered with wood chips. 6. The plastic head after demoulding is placed for 3 days, and the use effect is better; if conditions permit, put it in the refrigerator for storage, and its use effect is better.