High Strength Clear Liquid Silicone for Mold Making

high transparency rtv-2 platinum catalyst 30-40 A heat resistance

Minimum order quantity: A:1kg+B:100g(Note: The price of Part B is the same as Part A.)

Lead Time
Quantity(kilograms)1-10001000-5000≥5000
Est. Time(days)2-3 4-7To Be Negotiated

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1. Description

This series of addition-cure clear liquid silicone is a high-hardness and high-strength elastomeric material. It is a platinum-catalyzed RTV-2 silicone rubber, consisting of Part A, which is a viscous base, and Part B, which is a water-like platinum curing agent. When mixed in a weight ratio of 10A:1B, this compound can cure faster at room temperature or at slightly elevated temperatures.

The transparent property of the cured silicone rubber makes it an excellent choice for molds that require cutting after curing. Since the model is visible, it is easier to determine the parting line. This is also very useful when casting complex parts, as it ensures that the entire mold cavity is filled with casting material.

rtv clear liquid silicone

2. Feature

  1. High hardness, high strength, high transparency.
  2. Clear appearance allows split lines to be cut accurately in block molds.
  3. Very low shrinkage for extremely accurate molds.
  4. Can be used for high-temperature (250°C/482°F) casting applications.
  5. Outstanding release properties.
  6. Produces extremely fine detail from original.
clear liquid silicone

3. Application

This series of high-hardness clear silicone rubber materials exhibit excellent tear and tensile strength while maintaining a low shrinkage rate. They are suitable for applications that require very precise replication of the original part size, making them ideal for mold-making in jewelry and other similar products. Additionally, these materials have excellent release properties and exhibit outstanding molding durability when used with epoxy and polyurethane resins.

This series of silicone rubber is also recommended for rapid prototyping applications, such as TV sets, household appliances, mobile phones, photocopiers, console boxes, radiator grilles, and lampshades.

rapid prototyping

Rapid Prototyping

lost wax process

Lost Wax Process

epoxy resin silicone mold

Epoxy Resin Mold

diamond clear silicone mold

Diamond Clear 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-5230 A/B RTV-5240 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 80,000 90,000
Part B Viscosity, mPa.s ASTM D 4287 200 200
Part A Specific Gravity, g/cm3 ASTM D 792 1.06-1.08 1.06-1.08
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 - 16 18
Typical Properties of Cured Rubber @ 24 Hrs 25°C/77°F
Hardness, Shore A Durometer ASTM D 2240 30 40
Tear Strength, N/mm ASTM D 624 C 13.0 14.0
Tensile Strength, Mpa ASTM D 412 3.0 3.5
Elongation, % ASTM D 412 350 300
Shrinkage, % - ≤0.10 ≤0.10
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.

  • What are the advantages of using clear silicone rubber as a mold?
    When you need to cut the parting line between two molds, clear silicone rubber will help you see inside the mold so that you can accurately separate the two molds without damaging the internal rubber or main component.
  • Can I use heat to speed up the cure of clear liquid silicone?
    Heat accelerating the cure is possible, but this will produce some apparent shrinkage of the mold due to differences in volume contraction on cooling between the silicone rubber and the original. The higher the curing temperature, the greater the likely differences in dimensions. Certainly, if your project is not greatly affected by the shrinkage rate, this approach can help improve efficiency.
  • How about the shrinkage of the finished mold?
    Silicone is an elastomer material, shrinkage is unavoidable. If you need molds with minimal shrinkage, choose a high-hardness silicone.
  • Is this liquid silicone material suitable for application to textile cloth to make it non-slip? How well does it adhere to the fabric?
    There is indeed a liquid silicone that is applied to the fabric to make it non-slip, but not our clear silicone, which is not adhesive. Of course, you can contact us to provide you with consulting assistance.
  • I'm considering using epoxy resin with this mold, but I'm not sure what kind of finish I'll end up with. Will the finished product be glossy or matte? This information will help me decide whether to use this mold or look for another option.
    Silicone material does not inherently have a glossy or matte finish. When liquid silicone replicates a product, it mimics the surface characteristics of the original master. If the master has a glossy finish, the resulting silicone mold will also be shiny. When you remove epoxy resin from the mold, the finish of the resin will depend on the surface of the mold. Essentially, the surface finish of the resin will match the surface finish of the mold.
  • Can epoxy resin be poured into molds made with this product?
    Certainly! These molds are designed to work perfectly with epoxy resin, ensuring that your finished product turns out just as you imagined it. Whether you're creating jewelry or any other small objects, these silicone molds will help you achieve the results you're looking for. So go ahead and pour with confidence, knowing that your molds are up to the task!
  • Can leftovers be used later? If so, how long can an opened bottle be stored?
    If you haven't mixed them yet, you can store them without any problems, just make sure to close the bottle tightly.
  • I have noticed that when using a UV resin model, the silicone fails to cure properly. Is there a way to coat the UV resin model with something that will allow the silicone to cure?
    Yes, you can try clear acrylic lacquer.
  • Is it possible to create wedding bands using this product?
    When it comes to making small items such as rings and other types of jewelry, we recommend using 40 Shore A silicone for the mold to ensure optimal results. Note: Do not make the clear silicone mold too thin as it will tear easily.
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