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RTV-2 is a two-component room tempearture vulcanizing silicone. Depending on its curing mechanism, two type of RTV-2 are available-a condensation cure type and an addition cure type.
the condensation cure type is strongly dependent on the catalyst and produces by-products like alclhol, while the addition cure type is dependent on temperature and produces no by-products.
RTV-2 is capable of deep section cure and its cure rate can be controlled. Also, it provides excellent electrical insulation, heat resistancen cold resistance, weatheratility, and impact absorption, as the unique features of silicones. These properties result in superior ease of use for various applications and improvement of the quality and productuvity of finished produts. RTV-2 is used primarily as electrical insuiating and potting materials for electrical and electronics, vacuum casting mold and various forming molds. |
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| Application Geometry and Cure Chemistry Options |
HOW TO USE
Mixing - 1:1/Part A:Part B
YanTai E.S.T tech silicone 1:1 encapsulants are supplied in two parts that do not require lot matching. The 1:1 mix ratio, by weight or volume, simplifies the proportioning process. To ensure uniform distribution of filler, Parts A and B must each be thoroughly mixed prior to their combination in a
1:1 ratio. When thoroughly blended, the Part A and B liquid mixture should have a uniform appearance. The presence of light-colored streaks or marbling indicates inadequate mixing and will result in incomplete cure.
Due to the fast-curing characteristics of some encapsulants included in this datasheet, automated mix and dispense equipment should be utilized. In applications sensitive to air entrapment, deairing with 28 to 30 inches Hg vacuum is required.
Mixing -10:1/Base:Curing Agent
YanTai E.S.T tech silicone 10:1 encapsulants are supplied in two parts as lot-matched base and curing agent that are mixed in a ratio of 10 parts base to one part curing agent, by weight. After thoroughly mixing base and curing agent, agitate gently to reduce the amount of air introduced. Allowing the mixture to set for 30 minutes before pouring may be adequate for removal of the air introduced during mixing. If air bubbles are still present, vacuum deairing may be required. Deair in a container with at least four times the liquid volume to allow for expansion of material. Air entrapped in the mixture can be removed by using a vacuum of 28 to 30 inches Hg. Continue the vacuum until the liquid expands and settles to its original volume and bubbling subsides. This may take 15 minutes to 2 hours depending on the amount of air introduced during stirring. For best curing results, glassware and glass or metal stirring implements should be used. Mix with a smooth action that does not introduce excess air.
Pot Life/Working Time
Cure reaction begins with the mixing process. Initially, cure is evidenced by a gradual increase in viscosity, followed by gelation and conversion to a solid elastomer. Pot life is defined as the time required for viscosity to double after Parts A and B (base and curing agent) are mixed. Please refer to individual pot life for each silicone encapsulant.
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Processing and Curing |
Thoroughly mixed YanTai E.S.T tech silicone encapsulant may be poured/dispensed directly into the container in which it is to be cured. Care should be taken to minimize air entrapment. When practical, pouring/dispensing should be done under vacuum, particularly if the component being potted or encapsulated has many small voids. If this technique cannot be used, the unit should be evacuated
after the silicone encapsulant has been poured/dispensed.
YanTai E.S.T tech silicone encapsulants may be either room temperature (25oC/77oF) or heat cured. Room temperature cure encapsulants may also be heat accelerated for faster cure. Ideal cure conditions for each product are given in the Product Selection Table. |
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PREPARING SURFACES
In applications requiring adhesion, priming will be required for the silicone encapsulants. Contact
the Yantai E.S.T tech silicone for the correct primer to use with a given product. For best results, the primer should be applied in a very thin, uniform coating and then wiped off after application. After application, it should be thoroughly air dried prior to application of the silicone elastomer. Additional instructions for primer usage can be found in the YanTai E.S.T tech laboratory.
USEFUL TEMPERATURE RANGES
For most uses, silicone elastomers should be operational over a temperature range of -45 to 200oC (-49 to 392oF) for long periods of time. However, at both the low and high temperature ends of the spectrum, behavior of the materials and performance in particular applications can become more complex and require additional considerations.
For low-temperature performance, thermal cycling to conditions such as -55oC (-67oF) may be possible, but performance should be verified for your parts or assemblies. Factors that may influence performance are configuration and stress sensitivity of components, cooling rates and hold times, and prior temperature history.
At the high-temperture end, the durability of the cured silicone elastomer is time and temperature dependent. As expected, the higher the temperature, the shorter the time the material will remain useable.
COMPATIBILITY
Certain materials, chemicals, curing agents and plasticizers can inhibit the cure of YanTai E.S.T tech silicone encapsulants. Most notable of these include:
. Organotin and other organometallic compounds
.Silicone rubber containing organotin catalyst
.Sulfur, polysulfides, polysulfones or other sulfurcontaining materials
.Amines, urethanes or amine-containing materials
.Unsaturated hydrocarbon plasticizers
.Some solder flux residues
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