High Hardness Platinum Cured Liquid Silicone Rubber

hard odor free non toxic 40-50 A platinum based low shrinkage

Lead Time

Quantity(kilograms)	1-1000	1000-5000	≥5000
Est. Time(days)	2-3	4-7	To Be Negotiated

Contact for Detailed Quotation
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+86-158 9975 3674

+86-158 9975 3674
+86-158 9975 3674
TDS File

1. Description

This series of addition-cured (platinum-catalyzed) silicone is a flexible material with a higher hardness. Both Part A and Part B are semi-transparent viscous liquids, and they can be colored using organic silicone pigments to achieve a wide range of colors. When the two parts are mixed in a 1A:1B ratio by weight or volume, they can cure at room temperature within a few hours or can be accelerated by heating.

After curing, this series of silicone rubber materials are heat-resistant, non-toxic, and odorless. They have been tested and comply with FDA regulations for CFR 177.2600 extractable testing, making them safe for use in contact with food.

2. Feature

1A:1B ratio, easy to use.
Higher hardness for greater mold stability.
Very low shrinkage (below 0.1%) and good dimensional stability.
Heat resistant up to 250°C (482°F).
It reproduces fine details accurately.
Room temperature curing or heat accelerated curing.

3. Application

High-hardness addition-cure silicones are commonly utilized in applications that demand extremely precise dimensional replication of the original part, such as rapid prototyping. This series of silicones has minimal to zero shrinkage, making it an ideal choice when casting accuracy is required even after weeks or months have passed.

RTV-4140 is suitable for resin (polyurethane, polyester, epoxy), polyurethane rubber and foam, cement, concrete, etc. RTV-4150 is stiffer but less tear resistant, suitable for applications requiring dimensional stability and non-deformation, and is recommended for prototyping mold-making applications in composite/fiberglass part production, electronics and automotive industries.

Rapid Prototyping

Polyurethane Casting Mold

Thin Shell Model Casting

Cultural Brick Mold

4. Attention

Please use parts A and B of the same model and lot number. If different batches are used, suitability should be determined by testing.
For optimal results, mix and cure the material at 20-30°C (68-86°F) and 50% relative humidity. Addition-cured liquid silicone should not be used in humid conditions, as this may cause defective curing.
Lower temperatures and humidity will increase the working time of the material. Do not use platinum-cured silicone at temperatures below 15°C (60℉), as it may not cure properly or may be difficult to cure at all.
Platinum-cured liquid silicone needs to be used with care to avoid inhibition. Inhibition occurs when the platinum cure silicone doesn't fully cure due to contamination on the surface of the object being molded. Although it may appear to be fully cured on the surface, a tacky surface will be present after separation - this is called inhibition. Amines, tin compounds, sulfur-based clay, newly cast polyester, natural rubber such as latex and rubber gloves, PVC stabilizers, epoxy resin catalysts, UV curable resin, or urethane rubber may cause inhibition. If compatibility between the addition cure silicone and the surface is a concern, it is recommended to perform a small-scale test. Do not smoke during operation.

5. Safety

Under normal storage and handling conditions, these products are stable in airtight containers at room temperature and will not undergo any hazardous reactions.
Please keep out of reach of children.
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

When stored at room temperature (15 to 25°C / 60 to 77°F), the material has a shelf life of 24 months from the date of manufacture. Storing the material at higher temperatures may shorten the usable shelf life of unused materials. However, storing the product beyond the specified date on the certificate of analysis does not necessarily mean that the product is no longer usable.

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

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Parameter Item	Test Method	RTV-4140 A/B	RTV-4150 A/B
Unvulcanized Physical Properties @ 24 Hrs 25°C/77°F
Physical State	-	Liquid	Liquid
Form	-	Viscous	Viscous
Odor	-	Odorless	Odorless
Part A Color	ASTM E 1767	Translucent	Translucent
Part B Color	ASTM E 1767	Translucent	Translucent
Part A Viscosity, mPa.s	ASTM D 4287	22,000	35,000
Part B Viscosity, mPa.s	ASTM D 4287	20,000	32,000
Specific Gravity, g/cm³	ASTM D 792	1.08-1.10	1.08-1.10
Part A and Part B mixed @ 25°C/77°F
Mix Ratio by Weight or Volume (A:B)	-	1:1	1:1
Working Time, Minutes	-	40	40
Curing Time, Hours	-	8	10
Typical Properties of Cured Rubber @ 24 Hrs 25°C/77°F
Hardness, Shore A Durometer	ASTM D 2240	40	50
Tear Strength, N/mm	ASTM D 624 C	17.0	6.0
Tensile Strength, Mpa	ASTM D 412	4.6	5.0
Elongation, %	ASTM D 412	330	250
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 silicones is highly regarded for its exceptional demolding performance, making the use of a demolding agent unnecessary for most materials. However, in cases where the master pattern exhibits high porosity, a rough texture, numerous cracks and undercuts, or is difficult to demold, it is advisable to apply a thin layer of demolding agent. This not only facilitates the demolding process by reducing friction and adhesion but also helps to extend the lifespan of the mold.

Commonly used demolding agents include acrylic spray, Vaseline, silicone oil, and soapy water, among others. These agents provide effective release properties, allowing for easier removal of the molded object from the mold.

Step 3: Measuring & Mixing

Mix the desired amount of Parts A and B in a 1:1 (by volume or weight) ratio and thoroughly mix them together. Accurate measurement is essential to achieve the best physical properties of the cured rubber. If you wish to add color to the silicone material, incorporate the desired colorant into the mixture. Mix the colorant thoroughly to achieve a uniform color throughout the material.

Step 4: Vacuum Degassing

You can assess the need for vacuum degassing based on the specific requirements of each project, but it is still recommended for achieving a flawless finish. If using vacuum degassing, place the mixed silicone in a container that is 3-4 times larger than the volume of the liquid silicone and vacuum degas until the silicone rises and then collapses. Continue vacuum degassing for an additional 1 to 2 minutes.

Techniques to Reduce Air Bubbles:

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.
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

Pour the liquid silicone as soon as possible after mixing or vacuuming to achieve the best flow and air bubble release. The liquid silicone material should be poured at a depth of at least 0.5 cm above the highest point of the model surface. If the layer is too thin, the mold can tear easily.

Step 6: Demolding the Mold

Under normal circumstances, platinum-cure silicone rubber 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.

Is it heat-resistant after being made into a mold with this food-grade liquid silicone? As in can I bake it at a low temp?
Our silicone is a heat-resistant material, so it can be baked at low temperatures. In fact, silicone is often used in baking molds because it is non-stick and easy to clean.

Helpful (10) Not Helpful (9) Reply
Could I add solid fine mesh powders to this product for coloring purposes?
For optimal performance and successful curing of silicone, we highly recommend using specialized silicone pigments for coloring instead of adding any powders to the mixture. The addition of powders may weaken the overall performance of the silicone and affect its curing process. Furthermore, it's important to note that platinum-cured silicone can be sensitive to certain chemical elements, which may result in curing inhibition.

Helpful (9) Not Helpful (10) Reply
I've been trying to make molds out of 3D-printed UV resin masters lately, but the platinum-cure liquid silicone has been failing to cure. I've tried curing it at different temperatures and it still doesn't work.
What material are your 3D-printed molds made of? Is the liquid silicone you're using cured in other situations, such as in disposable plastic cups? I recommend either baking the 3D-printed UV resin master at 60°C to evaporate potential solvents, or spraying the 3D-printed part with clear acrylic paint as a protective coating.

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Is it petrol resistant? To create a gasket for a carburetor?
In my opinion it is not fit for purpose.

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Is it compatible with 3D-printed objects with uv photopolymer resin?
To use a 3D-printed object made of UV-sensitive resin as a master, it should be fully hardened before use by exposing it to sunlight or an artificial UV light source. Alternatively, you can spray a layer of primer on the UV-photosensitive resin master model. Otherwise, the silicone on the contact surface may be a little sticky.

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