When using RTV-2 silicone material for mold making, some clients may consider adding silicone oil to dilute the liquid silicone, making it easier to flow and penetrate into small intricate areas. In addition, it can improve the defoaming effect. Now, let's analyze the impact of adding silicone oil on the performance of silicone materials.
Firstly, let's delve into the knowledge of silicone diluents. When diluting liquid silicone, silicone fluid is commonly used, specifically dimethyl silicone fluid. This type of silicone oil is non-reactive and serves to lower the mixed viscosity of tin-cured silicone or platinum-cured silicone. Moreover, silicone fluid can also function as a mold release agent during silicone mold making, enhancing the demolding effect and extending the lifespan of silicone molds.
liquid silicone and silicone oil
| Performance Item | Compared | Degree of Influence |
|---|---|---|
| Viscosity | Reduce | Larger |
| Operating Time | Prolonged | Smaller |
| Curing Time | Prolonged | Smaller |
| Hardness | Reduce | Larger |
| Tear Strength | Reduce | Larger |
| Tensile Strength | Reduce | Larger |
| Elongation Break | Reduce | Smaller |
Projected Performance Alterations
When 5% of silicone fluid is added, it reduces the mixed viscosity by 24%, Shore hardness by 13%, tensile strength by 13%, and tear strength by 12%.
When 10% of silicone fluid is added, it reduces the mixed viscosity by 45%, Shore hardness by 23%, tensile strength by 18%, and tear strength by 16%.
The estimated performance changes provided above are for reference only and may not be completely accurate. It is highly influenced by the type of silicone you are using and the viscosity of the added silicone oil. Since no two applications are exactly the same, it is recommended to conduct small-scale test applications to determine suitability for your project.
From the data provided above, it is evident that excessive addition of silicone oil can have adverse effects on the physical properties of the silicone material itself. Tear strength and tensile strength of the silicone decrease, significantly shortening the lifespan of silicone molds. Therefore, if your intention is to incorporate silicone oil for the purpose of diminishing the viscosity of liquid silicone, it is advisable to employ the silicone oil with the most minimal viscosity (50cps) as a diluting agent. Additionally, it is recommended to ensure that the quantity of silicone oil does not exceed 5% of the combined weight of the mixed silicone components (A+B). Typically, adding 1% to 3% is sufficient.
Dilution Precautions
The amount of silicone oil added should be a percentage of the total weight of Parts A and B of the RTV-2 silicone material. To begin, add the silicone oil diluent (up to 5%) to Part A of the RTV-2 silicone material. Once the desired viscosity is achieved, weigh the appropriate amount of Part B (catalyst) and mix it according to the instructions for the organic silicone mixing ratio you are using. It is important to note that the catalyst dosage will be calculated based on the total weight of the rtv-2 silicone base with the added diluent, rather than the weight of the base material before the diluent is added.
Summarize
The addition of a silicone oil diluent can extend the working time of liquid silicone and slow down the curing process. However, it is important to note that the tear strength, tensile strength, and Shore hardness will decrease proportionally with the amount of silicone oil added. To ensure the longevity of silicone, it is advised to refrain from adding silicone oil unless absolutely necessary. If viscosity reduction is indeed needed, opting for a low-viscosity silicone oil is recommended, and the addition should be minimal to preserve the material's properties.
