SES22330-50 A/B vs RTV-4105 Silicone Comparison

1. Technical Assessment

SES22330-50 A/B and RTV-4105 are both very soft addition-cure silicone systems intended for flexible molds, detailed parts and applications where easy demolding is important. SES22330-50 A/B is specified at 50 Shore 00, while RTV-4105 is specified at 5±1 Shore A. Because Shore 00 and Shore A are different hardness scales, the numerical values should not be treated as directly equivalent. The more useful comparison is how the two materials behave during mold making and demolding.

SES22330-50 A/B is positioned by Shin-Etsu as a low-durometer, low-viscosity molding material with high elongation and easy demolding. It uses a 1:1 mixing ratio and provides a published 95-minute working time. This extended window can be valuable when preparing detailed masters, performing careful deaeration or filling a mold slowly. RTV-4105 also uses a simple 1:1 system, but its published working time is approximately 30–40 minutes.

Viscosity is another practical difference. Shin-Etsu lists approximately 10,500 cP for the mixed SES22330-50 A/B material, while MinghuiLink publishes approximately 4,000±200 mPa·s for RTV-4105 Part A and 2,800±200 mPa·s for Part B. Because the manufacturers report different material states and measurement points, these figures should not be treated as a strict like-for-like viscosity ratio. The published values nevertheless indicate that RTV-4105 is the lower-viscosity option on the stated component basis.

The mechanical profile shows a clearer trade-off. SES22330-50 A/B publishes 1.60 MPa tensile strength, 4.0 N/mm tear strength and 660% elongation. RTV-4105 publishes 2.0±0.5 MPa tensile strength, 11±0.5 N/mm tear strength and 540±50% elongation. RTV-4105 therefore reports higher published tensile and tear strength, while SES22330-50 A/B reports higher elongation. For difficult demolding, higher elongation can provide greater stretch capability, while higher tear strength can be more relevant to resistance against cuts and crack propagation.

Very soft silicone is particularly useful for deep undercuts, delicate masters and shapes that require the mold to flex or peel away during demolding. The trade-off is reduced self-support and dimensional stability compared with firmer mold grades. Large or thin-section molds may therefore require a support shell, mother mold or other external structure. The appropriate choice depends on whether maximum flexibility or greater resistance to tearing is the more important requirement.

Cure time also differentiates the two products. MinghuiLink publishes an approximately 4-hour cure time for RTV-4105, while the current Shin-Etsu documentation provided for SES22330-50 A/B does not publish a numerical cure time. Following the comparison methodology, the SES22330 cure time should therefore be treated as Not publicly listed rather than estimated. RTV-4105 is consequently easier to evaluate when a defined production turnaround is required.

Both materials can be considered for intricate masters and undercut molds, but addition-cure silicone can be inhibited by certain contaminants such as some 3D-printing resin residues, sulfur-containing materials and amines. Compatibility testing with the actual master and surface treatment is recommended before production.

Overall, SES22330-50 A/B is better aligned with users who want an ultra-soft silicone with higher published elongation and a much longer working window. RTV-4105 is better suited to users who prioritize lower published component viscosity, higher published tensile and tear strength, and a clearly defined 4-hour cure cycle.

2. Technical Comparison

Technical Parameter	Shin-Etsu SES22330-50 A/B	MinghuiLink RTV-4105
Silicone Type	Addition-cure silicone	Platinum-cure silicone
Color	Translucent	Translucent
Specific Gravity	Not publicly listed	1.03–1.05 g/cm³
Mix Ratio	1A:1B by weight or volume	1A:1B by weight or volume
Shore Hardness	50 Shore 00	5±1 Shore A
Viscosity	10,500 cP (Mixed)	4,000±200 mPa·s* (Part A)
Working / Pot Life	95 min	30–40 min
Cure Time	Not publicly listed	4 hours
Tensile Strength	1.60 MPa	2.0±0.5 MPa
Tear Strength	4.0 N/mm	11±0.5 N/mm
Elongation	660%	540±50%
Shrinkage	Not publicly listed	≤0.1%
Temperature Resistance	Not publicly listed	Up to 250°C / 482°F
Technical Data Sources	SES22330-50 A/B	RTV-4105

Data Methodology: All competitor figures are taken from publicly available technical data and are labelled with their source. Missing values are marked "Not publicly listed" and are not estimated. Shore 00 and Shore A are different hardness scales and should not be treated as directly interchangeable. Viscosity values are reported according to the manufacturers' stated measurement points and should not be treated as a strict like-for-like comparison where test bases differ. SES22330-50 A/B values are typical properties and are not intended as specification guarantees. Specifications may change, so always check the latest manufacturer documentation and conduct application-specific testing before production use.

3. Key Differences

Key Factor	Shin-Etsu SES22330-50 A/B	MinghuiLink RTV-4105	What It Means
Hardness Scale	50 Shore 00	5±1 Shore A	Both are very soft silicone systems, but they use different Shore hardness scales and should not be treated as numerically equivalent.
Working Window	95 min	30–40 min	SES22330 provides substantially more processing time for detailed masters, careful deaeration and slower pouring.
Mixing System	1:1	1:1	Both use a simple equal-parts system, so mixing ratio is not a meaningful differentiator.
Published Viscosity	10,500 cP mixed	4,000±200 mPa·s Part A	RTV-4105 publishes lower component viscosity values, although the measurement points are not directly like-for-like.
Tensile Strength	1.60 MPa	2.0±0.5 MPa	RTV-4105 reports the higher published tensile-strength value, subject to differences in test conditions.
Tear Strength	4.0 N/mm	11±0.5 N/mm	RTV-4105 reports substantially higher published resistance to tear propagation.
Elongation	660%	540±50%	SES22330 publishes higher elongation, providing greater reported stretch capability during demanding demolding.
Cure Time	Not publicly listed	4 h	RTV-4105 has a clearly published cure time, making production scheduling easier to define.
Primary Positioning	Ultra-soft, high-elongation mold material with extended working time	Very soft, lower-viscosity silicone with higher tear strength and faster published cure	The main choice is between maximum stretch and processing latitude versus tear resistance, handling and defined turnaround.

4. Application Comparison

Application	SES22330-50 A/B	RTV-4105	Key Consideration
Deep Undercut Molds	Strong candidate	Strong candidate	Both are very soft materials suited to flexible demolding; SES22330 publishes higher elongation, while RTV-4105 publishes higher tear strength.
Delicate / Intricate Masters	Strong candidate	Strong candidate	Both can flex around delicate features and detailed geometry; material selection should also consider required mold support and casting conditions.
Slow or Detailed Mold Preparation	Strong candidate	Suitable	The 95-minute SES22330 working window gives substantially more time for careful mixing, deaeration, positioning and controlled pouring.
Thin Mold Sections	Suitable with testing	Strong candidate	RTV-4105 publishes much higher tear strength, which may be advantageous where thin sections are exposed to repeated cutting, stretching or handling.
Repeated Demolding	Strong candidate	Strong candidate	SES22330 offers higher published elongation, while RTV-4105 offers substantially higher published tear strength; the dominant failure mode should guide selection.
Small-Batch Manual Mixing	Strong candidate	Strong candidate	Both use a simple 1:1 mixing system, making either suitable for manual small-batch preparation.
Rapid Mold Turnaround	Not clearly established	Strong candidate	RTV-4105 has a published 4-hour cure, while SES22330's numerical cure time is not publicly listed.
3D-Printed Masters	Suitable with compatibility testing	Suitable with compatibility testing	Some printing resins, sulfur-containing materials, amines and coatings can inhibit addition-cure silicone. Testing the actual master is recommended before production.

Source basis: Application suitability is based on the manufacturers' published application information and general material characteristics. Actual compatibility should be validated with the intended master, casting material, mold design and production process. Very soft silicone molds may require external support to maintain dimensional stability.

5. FAQ

1. Is RTV-4105 a direct replacement for SES22330-50 A/B?

RTV-4105 can be evaluated as an alternative for many very soft flexible-mold applications, but it should not be treated as a direct one-for-one replacement. SES22330-50 A/B uses a 50 Shore 00 specification and provides 660% elongation with a 95-minute working time, while RTV-4105 uses 5±1 Shore A and provides higher published tensile and tear strength, lower component viscosity and a 4-hour cure. The actual mold geometry, flexibility requirement and production process should be checked before switching.

2. Which is better for deep undercuts and easy demolding?

Both materials are intended for very flexible molds and can be considered for deep undercuts. SES22330-50 A/B publishes higher elongation at 660%, while RTV-4105 publishes higher tear strength at 11±0.5 N/mm. SES22330 may therefore offer more stretch during difficult demolding, while RTV-4105 may provide greater resistance to tearing or damage. Actual performance depends on mold thickness, geometry and demolding technique.

3. Which silicone is better when the mold takes a long time to prepare?

SES22330-50 A/B is better suited to slower mold preparation because its published working time is approximately 95 minutes, compared with 30–40 minutes for RTV-4105. The longer window can be useful for detailed masters, careful deaeration, positioning and controlled pouring. RTV-4105 is more appropriate when a shorter working stage is acceptable and faster curing is preferred.

4. Which has better tear resistance, SES22330-50 A/B or RTV-4105?

RTV-4105 reports the higher published tear-strength value at 11±0.5 N/mm, compared with 4.0 N/mm for SES22330-50 A/B. SES22330-50 A/B, however, publishes higher elongation at 660% versus 540±50% for RTV-4105. These properties address different failure mechanisms, so the better choice depends on whether maximum stretch or resistance to tearing is more important.

5. Which one is easier and faster to process?

RTV-4105 is generally more convenient when routine processing speed is important. Both products use a simple 1:1 mixing system, but RTV-4105 publishes lower component viscosities, a 30–40 minute working time and a 4-hour cure. SES22330-50 A/B provides a much longer 95-minute working window, but its numerical cure time is not publicly listed.

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Disclaimer

Competitor specifications are based on publicly available manufacturer documentation, with links to the original sources where available. Missing values are shown as “Not publicly listed” and are not estimated or inferred. Specifications may change, so always check the latest manufacturer documentation and conduct application-specific testing before production use. Product names and trademarks belong to their respective owners. This comparison is provided for technical and informational purposes only and is not endorsed by the brands mentioned.