Detailed Analysis of RTV Silicone

What is RTV Silicone?

RTV Silicone, room temperature vulcanized silicone rubber, is a type of silicone rubber made from a two-component system,which is in a liquid state, and it begins to solidify after contact with air, and the entire curing process can be carried out at room temperature without additional high temperature and without the use of a mold. RTV Silicone can achieve a hardness range of very soft to medium-- from 15 to 40 Shore A, and which can be cured with a catalyst consisting of either platinum or a tin compound such as dibutyltin dilaurateused is used for low-temperature over-molding, making molds for reproducing, and lens applications for some optically clear grades.

Room Temperature Vulcanizing (RTV) silicone is a rubber polymer used to create molds, prototypes, and sealant. It is extremely flexible and quite tear resistant. RTV silicone can be poured, sprayed, brushed, or pumped onto a surface.

In addition, some perfusion molded silicone rubber products also use RTV Silicone, such as some adult products. In general, in addition to a small number of seal waterproof applications, HTV silicone rubber and RTV silicone rubber can not be interchangeable in application.

HTV, high temperature vulcanized silicone rubber. The raw material is an amorphous gel, similar to plasticine. If the silicone rubber raw material is shaped, it must be supplied with a high temperature of about 160 °C. In order to achieve precise structure and size, the raw material must be put into the mold to complete shaping. Therefore, HTV is also called molded silicone. Typical products include: silicone buttons, silicone rubber seals, silicone sleeves and other products.

How RTV Silicone is Made?

RTV silicone is mixed with the curing agent or vulcanizing agent and through vulcanization process to be a good chemical resistance and high-temperature resistance and widely used for prototypes, furniture, sculpture, and architectural elements. This  vulcanization process involves mixing rubber polymers with additives such as sulfur in order to make the silicone harder or more flexible. Humidity in the air cures RTV-1, a single compound RTV silicone type, which is available in both fluid and paste forms. A dual compound RTV silicone type known as RTV-2 is mixed together, cures at room temperature, and is available in solid, gel, and foam forms.

RTV Silicone's Vulcanization method

The condensation reaction of the condensed one-component room temperature vulcanization should be initiated by the moisture in the air. The vulcanization reaction of the condensed two-component room temperature vulcanized silicone rubber is not caused by the moisture in the air but by the catalyst. Typically, the raw silicone rubber, the filler, and the cross-linking agent are packaged as one package, the catalyst is packaged separately as another component, or use other combinations way, but the catalyst and the cross-linking agent must be packaged separately . Regardless of what’s the packaging method, curing begins only when the two components are completely mixed together. The vulcanization reaction of the addition-molded two-component greenhouse vulcanized silicone rubber is carried out by an addition reaction of a silicon hydrogen bond and a silicon vinyl group in the presence of a platinum metal catalyst.

RTV Silicone's Advantages

RTV silicone has good resistance to heat and chemicals. RTV silicone is also very flexible, even when dried. It has no release agents, so do not need to clean up residue. RTV silicone is also non-toxic and can cure immediately when it comes in contact with moisture in the air. RTV silicone is available in both dual and single-component products.

RTV Silicone's Disadvantages

RTV silicone is expensive and is easy to be dirty and other residues will sticking to it easily. Since air moisture cures RTV, it can be difficult to apply as a paste and must be applied to a surface quickly. RTV silicone is also very thick and porous and the user must degas it with a vacuum in order to remove any air bubbles that may interfere with its application.