Soft Clear Liquid Silicone for Mold Making

high transparency rtv-2 low shrinkage 5-20 A platinum based
Lead Time
Quantity(kilograms)1-10001000-5000≥5000
Est. Time(days)2-3 4-7To Be Negotiated

1. Description

This series of addition-cured clear liquid silicone is an elastomeric material that ranges from low to medium hardness. It is a platinum-catalyzed RTV-2 silicone rubber, where Part A is a viscous base and Part B is a platinum curing agent similar to water.

When mixed in a 10A:1B ratio by weight, the compound can cure at room temperature or faster at slightly elevated temperatures. The high transparency of this series of organic silicones makes it particularly suitable for making molds that allow for viewing of the casting's interior, as well as for manufacturing silicone components.

clear liquid silicone

2. Feature

  1. Excellent dimensional stability (shrinking≤0.1%).
  2. Excellent release properties.
  3. Transparent appearance allows split lines to be cut accurately in block molds.
  4. Platinum catalyst, imparts no taste or odors.
  5. Excellent heat resistance of up to 250°C (482°F).
  6. Produces extremely fine detail from original.
soft transparent silicone

3. Application

This series of addition-cure clear liquid silicone exhibits excellent mold release properties, good chemical resistance, and high dimensional stability. After curing, the transparent silicone rubber is soft and elastic, making it highly suitable for casting complex or intricately shaped products, and the castings can be easily removed from the silicone molds. It is an ideal material for creating transparent silicone molds.

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Resin Clear Mold

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Cosmetic Silicone Mold

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Resin Jewelry Mold

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Resin Crafts Mold

4. Attention

  1. It is important to use Part A and Part B of the same model and lot number. If different lots are used, suitability should be determined by testing.
  2. For optimal results, it is recommended to mix and cure the material at a temperature of 25°C (77°F) and with 50% relative humidity. It is important to avoid using addition cure silicone rubber in humid conditions, as this can lead to faulty curing.
  3. It is not recommended to cure the material at temperatures below 20°C (68°F). Lower temperatures have been found to result in reduced final cure hardness and may affect the overall properties of the material.
  4. Curing the material at room temperature ensures the lowest possible shrinkage. The use of higher temperatures may result in excessive shrinkage occurring.
  5. It is essential to tightly seal the containers of the platinum catalyst after use. If the catalyst is exposed to air for an extended period, it will undergo hydrolysis. One visible sign of hydrolysis is the formation of a film or crust on the surface of the catalyst. It is not advisable to use hydrolyzed catalyst as it may result in incomplete curing.
  6. The clear liquid silicone belongs to the platinum-cured silicone rubber group and may inhibit cross-linking when it comes into contact with certain materials. If there is uncertainty about the compatibility between the silicone and the surface material, it is recommended to conduct small-scale testing. Smoking should be avoided during the operation process.

5. Safety

  1. Under normal storage and handling conditions, these products are stable in airtight containers at room temperature and will not undergo any hazardous reactions.
  2. Please keep out of reach of children.
  3. First Aid Measures:
    • Skin Contact: Wash the affected skin thoroughly with soap and water. Seek medical attention if symptoms persist after washing.
    • Eye Contact: In the event of contact with the eyes, rinse them thoroughly with clean water for at least 15 minutes. Seek medical attention if irritation persists after rinsing.
    • Inhalation: Under normal conditions of intended use, this material is not expected to be an inhalation hazard.
    • Ingestion: Do not induce vomiting unless instructed by a physician. Rinse mouth thoroughly. Seek medical attention if symptoms occur.

Please note that these measures are general guidelines. In case of an emergency, always consult a medical professional or seek immediate medical attention.

6. Storage

The material should be stored at room temperature (15 to 25°C / 60 to 77°F) and has a shelf life of 12 months from the date of production. Storing the material at higher temperatures can shorten the shelf life of unused materials. As storage time increases, the viscosity of the liquid silicone may also increase. However, exceeding the specified date on the analysis certificate does not necessarily mean that the product is no longer usable. In this case, it is necessary to check the properties required for the intended use for quality assurance reasons.

Containers that have been opened must be carefully resealed to prevent leakage. Store in a cool, dry place with adequate ventilation. Keep away from incompatible materials (bases and acids), open flames, and high temperatures.

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Parameter Item Test Method RTV-5210 A/B RTV-5220 A/B
Unvulcanized Physical Properties @ 24 Hrs 25°C/77°F
Physical State - Liquid / Fluid Liquid / Fluid
Form - Viscous Viscous
Odor - Odorless Odorless
Part A (Base) Color ASTM E 1767 Transparent Transparent
Part B (Catalyst) Color ASTM E 1767 Clear Clear
Part A Viscosity, mPa.s ASTM D 4287 40,000 50,000
Part B Viscosity, mPa.s ASTM D 4287 200 200
Part A Specific Gravity, g/cm3 ASTM D 792 1.05-1.07 1.05-1.07
Part B Specific Gravity, g/cm3 ASTM D 792 0.96 0.96
Part A and Part B mixed @ 25°C/77°F
Mix Ratio by Weight (A:B) - 10:1 10:1
Working Time, Minutes - 60 60
Curing Time, Hours - 12 14
Typical Properties of Cured Rubber @ 24 Hrs 25°C/77°F
Hardness, Shore A Durometer ASTM D 2240 10 15
Tear Strength, N/mm ASTM D 624 C 8.0 10.0
Tensile Strength, Mpa ASTM D 412 2.0 2.5
Elongation, % ASTM D 412 450 400
Shrinkage, % - ≤0.15 ≤0.15
Heat Resistance, °C (°F) - 250 (482) 250 (482)

Step 1: Model Preparation

The master pattern should be thoroughly cleaned and dried. If the master model is fragile, weak, or porous, it may be necessary to apply a consolidant or sealant, and possibly fill in deep holes or crevices.

Step 2: Applying Release Agent

This series of clear silicone material exhibits excellent mold release properties, and in most cases, a mold release agent is not required for most materials. However, if the master pattern is particularly porous or rough, or has many crevasses and undercuts, or not prone to spalling, it is recommended to apply a thin layer of mold release agent to facilitate mold release, which can prolong mold life.

Step 3: Measuring & Mixing

According to the instructions, mix the required quantities of Part A and Part B in the correct weight ratio, and thoroughly blend them together. Accurate weighing and thorough mixing are essential for achieving the optimal physical properties of the cured rubber.

Step 4: Vacuum Degassing

The clear liquid silicone raw material has a high viscosity, and to ensure that there are no air bubbles in the mold, it is necessary to use a vacuum pump to degas. For vacuum degassing, it is recommended to mix Parts A and B in a mixing container that is 3 to 4 times larger than the volume of silicone rubber and deaerate until the mass of rubber rises and then collapses. Continue the process for an additional two minutes. If conditions permit, another round of vacuum degassing will be more effective after pouring the silicone.

Techniques to Reduce Air Bubbles:

  1. Hold the silicone container high above the master pattern and allow it to flow down slowly in a thin stream. This helps to break up any air bubbles as the silicone flows.
  2. Temporarily incline the master pattern at an angle and pour the liquid silicone onto the higher end, allowing it to flow down over the rest of the pattern. Once the silicone reaches the lower end, lay the pattern flat and/or tilt or rotate it as necessary to achieve even coverage.

These techniques can be used alone or in combination with each other. Additionally, reducing the temperature and decreasing the ratio of curing agent can extend the working time and help to reduce air bubbles.

Step 5: Pouring Silicone

After vacuuming, it is important to pour the clear liquid silicone as soon as possible to ensure optimal flow and release of air bubbles. The liquid silicone should be poured to a depth of at least 0.5cm over the highest point of the model surface to prevent tearing of the mold. If the layer of silicone is too thin, it can easily tear the mold.

Step 6: Demolding the Mold

Under normal circumstances, clear liquid silicone cures within the specified demold time at room temperature (25℃/77°F). Higher temperatures will result in shorter curing times, while lower temperatures may require more time for curing to complete.

After the specified curing time has elapsed, the outer surface of the mold should feel hard and dry. If the mold's hardness does not change after a period of time, it is usually safe to remove or demolded. However, if the silicone is still soft or sticky, it may need more time to cure.

  • Is this product based on platinum or tin curing? I am asking in the context of 3D printed masters, which are said to have adverse effects on curing.
    If you are using UV resin as your 3D printing material, the contact surface with platinum-cured silicone may become sticky and unable to cure. In this case, you need to apply a primer on the surface of the master to protect it. Tin-cure silicones are not affected by this issue.
    Helpful (13) Not Helpful (8) Reply
  • What temperature does this clear silicone need to cure?
    Our clear liquid silicone is RTV silicone, which means it can be cured at room temperature. However, the temperature should not be lower than 20°C/68°F, otherwise it may be difficult to cure or the curing hardness may not meet expectations. Alternatively, you can increase the temperature to speed up the cure. This typically takes 1-2 hours at 60-80°C (140-176°F).
    Helpful (7) Not Helpful (10) Reply
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