描述
Santoprene 121-80B265 is a black thermoplastic vulcanizate (TPV) from Celanese specifically developed for automotive glass run channel (GRC) corner molding, weatherseal corner joints and end-cap molding.
The grade combines a built-in low coefficient of friction with good bonding to both Santoprene-type TPV and vulcanized EPDM rubber. This makes it especially useful where an injection-molded corner or end cap must join an existing extruded TPV or EPDM weatherseal profile.
Celanese positions Santoprene 121-80B265 as a low-friction injection molding material designed to replace thermoset EPDM rubber in suitable automotive glass-run-channel corner molding applications.
A major advantage is process efficiency. Thermoset EPDM corner molding normally requires a curing step. A TPV such as Santoprene 121-80B265 can be injection molded using thermoplastic processing, which can enable shorter cycle times and easier process automation.
The material is formulated for good adhesion to vulcanized EPDM and TPV. This is important because automotive weatherseal corners and end caps often rely on a relatively small contact interface between the molded material and the extruded profile.
The grade also offers good flowability and strong shear-thinning behavior. The apparent melt viscosity decreases as shear rate increases, helping the material fill complex corner geometries, narrow flow paths and detailed mold features.
Another key feature is surface quality. Celanese highlights excellent surface aesthetics, along with low-friction retention after heat aging and no surface bleeding.
For glass run channels, this matters because visible corner moldings need to match adjacent extruded profiles in appearance while the sliding surface must continue to provide controlled friction against moving window glass.
Current Celanese Materials Database information lists Santoprene 121-80B265 at approximately Shore A 79, with 32 kN/m tear strength, 46% compression set at 70°C for 24 hours, a low-temperature brittleness value of approximately -64°C, and density of approximately 0.919 g/cm³.
The grade is also identified as UV stabilized or stable to weather, supporting exterior automotive sealing applications.
Current processing data lists injection molding and multi-injection molding as the principal processing methods.
For more TPV products, visit our TPV Thermoplastic Vulcanizates Product Category →.
For the broader Celanese TPV portfolio, see the Official Celanese Santoprene & Geolast Product Finder →.
Key Features of Santoprene 121-80B265
| Feature | Engineering Benefit |
|---|---|
| Built-In Low Coefficient of Friction | Supports glass-run-channel and sliding-window applications |
| Low Friction Retention After Heat Aging | Helps preserve sliding performance during long-term service |
| No Surface Bleeding | Helps maintain surface appearance and friction behavior |
| Adhesion to Vulcanized EPDM | Supports molded corners and end caps on EPDM profiles |
| Adhesion to TPV | Supports TPV-to-TPV corner molding and multi-material sealing designs |
| Shore A 79 | Provides a firm elastomeric response for automotive sealing components |
| 32 kN/m Tear Strength | Supports durability in molded corner and edge geometries |
| -64°C Low-Temperature Brittleness | Supports cold-climate automotive service |
| Good Flowability | Helps fill complex injection-molded geometries |
| High Shear-Thinning Behavior | Improves flow under high-shear injection conditions |
| Excellent Surface Aesthetics | Supports visible weatherseal corner applications |
| UV / Weather Stabilized | Suitable for exterior automotive sealing environments |
| Thermoplastic Processing | Can shorten processing cycles versus thermoset EPDM in suitable applications |
| 20% Maximum Regrind Level | Supports controlled manufacturing-stream recycling |
The core value of Santoprene 121-80B265 is not simply its hardness. It is the combined package of low friction, EPDM/TPV bonding, flowability, weather resistance and corner-molding processability.
Typical Applications for Santoprene 121-80B265
Santoprene 121-80B265 is primarily an automotive sealing material.
| Application Area | Typical Use |
|---|---|
| Glass Run Channel Corner Molding | Injection-molded corners joining extruded automotive GRC profiles |
| Weatherseal Corner Joints | Molded connections between TPV or EPDM weatherseal sections |
| Weatherseal End Caps | Injection-molded end closures for automotive sealing profiles |
| Window Sealing Systems | Low-friction components contacting moving automotive glass |
| EPDM Profile Overmolding | Molded TPV sections bonded to vulcanized EPDM profiles |
| TPV Profile Overmolding | Molded corners and terminations bonded to TPV extrusions |
| Complex Automotive Seal Geometries | High-flow injection molded parts with detailed mold features |
| Exterior Automotive Seals | UV- and weather-exposed sealing components |
The strongest application fit is where the component requires low friction against glass plus reliable bonding to an extruded TPV or EPDM profile.
Typical Properties of Santoprene 121-80B265
Physical Properties
| Property | Typical Value | Test Method |
|---|---|---|
| Density | 919 kg/m³ / 0.919 g/cm³ | ISO 1183 |
| Shore A Hardness, 15 s | 79 | ISO 48-4 / ISO 868 |
| Resin Identification | TPV | ISO 1043 |
| Part Marking Code | >TPV< | ISO 11469 |
| Color | Black | Manufacturer information |
| Delivery Form | Pellets | Manufacturer information |
| Special Characteristic | UV stabilized / weather stable | Manufacturer information |
Mechanical Properties
| Property | Typical Value | Test Method |
|---|---|---|
| Low-Temperature Brittleness | -64°C | ISO 812 |
| Shore A Hardness, 15 s | 79 | ISO 48-4 / ISO 868 |
| Compression Set, 70°C / 24 h | 46% | ISO 815 |
| Tear Strength, Normal | 32 kN/m | ISO 34-1 |
The current Celanese grade sheet does not publish tensile stress or elongation values for this specific grade. Those values should not be copied from nearby 121-80B-series products because the formulations and functional packages differ.
Flammability
| Property | Typical Value | Test Method |
|---|---|---|
| FMVSS Class | B | ISO 3795 / FMVSS 302 |
Functional Performance
Celanese identifies several important functional characteristics for Santoprene 121-80B265:
- Built-in low coefficient of friction
- Low-friction retention after heat aging
- No surface bleeding
- Good bonding to TPV
- Good bonding to vulcanized EPDM rubber
- Good flowability
- Excellent surface aesthetics
- Improved heat-aging performance
- UV/weather stabilization
These application-specific features are the main reasons the grade is used in automotive weatherseal corner molding.
Why Choose Santoprene 121-80B265?
The main reason to select Santoprene 121-80B265 is that it addresses multiple problems encountered in automotive glass-run-channel corner molding at the same time.
A GRC corner needs to join smoothly with an extruded weatherseal profile. The molded material must bond to that profile, reproduce a complex geometry, maintain a good visible surface and avoid creating excessive friction against moving window glass.
If a material flows poorly, the corner may show incomplete filling, weld lines or surface defects. If adhesion is poor, the molded corner may separate from the EPDM or TPV profile. If the coefficient of friction is too high, window movement can become noisy or inconsistent.
If low-friction additives migrate or bleed to the surface, appearance and long-term friction behavior can deteriorate.
Santoprene 121-80B265 is designed around these combined requirements.
Celanese specifically highlights the material’s low-friction behavior without surface bleeding, along with its retention of low friction after heat aging.
The grade’s strong shear-thinning behavior helps injection molding of complex shapes. Higher shear reduces apparent viscosity, making it easier to fill detailed corner geometries.
Its Shore A 79 hardness provides a relatively firm sealing response, while the published -64°C brittleness value supports cold-weather performance.
The 32 kN/m tear strength is also relevant for corners, lips and edges that may experience installation loads.
Another advantage is compatibility with the manufacturing process. Santoprene 121-80B265 is intended to reduce processing time compared with thermoset EPDM corner molding because it is processed as a thermoplastic rather than requiring a conventional vulcanization cycle.
For automotive suppliers producing GRCs, window weatherseals and exterior sealing profiles, this combination makes the grade significantly more specialized than a standard 80 Shore A TPV.
Processing Guidelines for Santoprene 121-80B265
Santoprene 121-80B265 is intended primarily for:
- Injection molding
- Multi-injection molding
- Overmolding onto TPV profiles
- Overmolding onto vulcanized EPDM profiles
Grade-Specific Injection Conditions
| Processing Parameter | Celanese Guidance |
|---|---|
| Drying Recommended | Yes |
| Drying Temperature | 65°C |
| Drying Time, Dehumidified Dryer | ≥3 hours |
| Processing Moisture Content | ≤0.08% |
| Maximum Regrind Level | 20% |
| Optimum Melt Temperature | 220°C |
| Minimum Melt Temperature | 210°C |
| Maximum Melt Temperature | 230°C |
| Optimum Mold Temperature | 50°C |
| Minimum Mold Temperature | 40°C |
| Maximum Mold Temperature | 60°C |
| Recommended Screw Speed | 100–200 rpm |
| Optional Back Pressure | 0.3–0.7 MPa |
| Holding Pressure | Approx. 50–75% of actual injection pressure |
Celanese also gives a broader Santoprene TPV family processing window of approximately 175–230°C.
Bonding to EPDM Sponge Profiles
For good bonding onto an EPDM sponge profile, Celanese recommends:
- Fast injection speed, approximately 60–100 mm/s
- High melt temperature
- Warm mold
- Moderate injection pressure
- Relatively low holding pressure to avoid profile deformation
- Accurate positioning of the extruded profile in the mold
- Sufficient cooling time to initiate recrystallization at the contact interface
These recommendations are especially important for weatherseal corner molding, where the molded material must create strong surface interaction with the existing profile.
Shear-Dependent Flow
Santoprene TPV has relatively high viscosity at low shear rates. As the shear rate increases, viscosity decreases.
For Santoprene 121-80B265, this means smaller gates and higher shear rates can improve melt flow. Celanese also notes that increasing temperature alone has relatively little influence on TPV melt viscosity compared with changing shear conditions.
Material Compatibility
Celanese states that Santoprene TPV is incompatible with acetal (POM) and PVC.
Processors should purge the barrel, screw, hot runner and other melt-contact surfaces carefully when changing between these materials.
Santoprene 121-80B265 vs. Santoprene 121-80B260
| Feature | Santoprene 121-80B265 | Santoprene 121-80B260 |
|---|---|---|
| Material Family | TPV | TPV |
| Color | Black | Black |
| Main Positioning | Low-friction weatherseal / GRC corner molding | Low-friction complex hard weatherseal corner molding |
| Bonding to TPV | Yes | Yes |
| Bonding to Vulcanized EPDM | Yes | Yes |
| Low-Friction Function | Built in | Built in |
| Surface Bleeding | Designed to avoid bleeding | Designed to avoid bleeding |
| Shore A Hardness | 79 | 78 |
| Density | 0.919 g/cm³ | 0.910 g/cm³ |
| Compression Set, 70°C / 24 h | 46% | 62% |
| Tear Strength | 32 kN/m | Not listed in the current B260 sheet used for this comparison |
| Low-Temperature Brittleness | -64°C | Not listed in the current B260 sheet used for this comparison |
| 100% Tensile Stress | Not published in current B265 sheet | 3.5 MPa |
| Tensile Stress at Break | Not published in current B265 sheet | 11 MPa |
| Elongation at Break | Not published in current B265 sheet | 640% |
Both grades target low-friction automotive weatherseal corner molding and bonding to TPV or vulcanized EPDM.
Santoprene 121-80B265 should be evaluated when the current B265 functional package, improved heat-aging positioning and published lower compression-set value are important.
Santoprene 121-80B260 remains a closely related alternative for complex hard corner molding of dense extruded weatherseals.
Because Celanese does not publish identical property sets for the two grades, selection should be based on the required weatherseal construction, surface/friction target, bonding trials and the current grade-specific TDS.
Related Products
Santoprene 121-80B260 – Black low-friction TPV for complex hard corner molding and end caps on dense TPV or EPDM automotive weatherseals.
Santoprene 121-80B200 – Black UV-resistant TPV with enhanced bonding to TPV and vulcanized EPDM, useful where a small bonding area or thin weatherseal geometry is important.
Santoprene 121-70B260 – Related automotive weatherseal TPV option for applications requiring a softer hardness range.
View More TPV Thermoplastic Vulcanizates →
Technical Documents for Santoprene 121-80B265
| Document Type | Description |
|---|---|
| TDS | Current Celanese physical, mechanical and processing data |
| SDS | Safety Data Sheet |
| Automotive Specification Information | Current grade sheet references GAC and General Motors specifications |
| Santoprene Product Finder | Celanese TPV portfolio and grade-selection guide |
| Injection Molding Guide | Processing and mold-design guidance |
| COA | Batch-specific quality information where available |
Current Celanese Materials Database information references GAC QJ/GAC 1240.022 and General Motors GMW15825P-TPV(EPDM+PP)-Type-6 for this grade.
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FAQ About Santoprene 121-80B265
Q1: What is Santoprene 121-80B265?
Santoprene 121-80B265 is a black low-friction TPV from Celanese designed for automotive glass-run-channel corner molding, weatherseal corners and end caps.
Q2: What is the hardness of Santoprene 121-80B265?
The current Celanese value is approximately Shore A 79.
Q3: Does Santoprene 121-80B265 bond to EPDM rubber?
Yes. Celanese specifically states that the grade adheres to vulcanized EPDM rubber as well as TPV.
Q4: Is Santoprene 121-80B265 a low-friction grade?
Yes. It contains built-in low-coefficient-of-friction functionality and is designed to retain low friction after heat aging without surface bleeding.
Q5: What is the low-temperature performance?
The current low-temperature brittleness value is approximately -64°C according to ISO 812.
Q6: What is the compression set?
Current Celanese data lists approximately 46% at 70°C for 24 hours.
Q7: What is the tear strength?
Current grade data lists approximately 32 kN/m.
Q8: What melt temperature is recommended?
The current injection range is approximately 210–230°C, with an optimum around 220°C.
Q9: Does Santoprene 121-80B265 require drying?
Yes. Current grade data lists drying as recommended, with 65°C for at least 3 hours and processing moisture at or below 0.08%. Celanese’s broader processing note also references desiccant drying for 3 hours at 80°C.
Q10: What is the difference between Santoprene 121-80B265 and 121-80B260?
Both are black low-friction TPV grades for automotive weatherseal corner molding and both bond to TPV and vulcanized EPDM. Santoprene 121-80B265 is positioned with improved heat-aging performance and currently shows 46% compression set, while B260 is positioned for complex hard corner molding and shows 62% compression set in its current sheet.
Request Santoprene 121-80B265 Price & Technical Support
For pricing, availability, technical documents or application support for Santoprene 121-80B265, please provide:
- Required quantity
- Destination country or port
- Automotive weatherseal application
- Glass run channel, corner joint or end-cap design
- TPV or vulcanized EPDM substrate
- Bonding area and profile geometry
- Required coefficient-of-friction performance
- Heat-aging conditions
- Low-temperature requirement
- Injection-molding machine and gate design
- OEM specification requirement
- TDS, SDS or COA requirement
- Sample requirement, if applicable
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