Celanese Hostaform® C 9021 GV1/10 POM
Hostaform® C 9021 GV1/10 Acetal (POM) Copolymer
Abstract
This report provides an exhaustive technical analysis of Celanese Hostaform® C 9021 GV1/10, a 10% glass fiber-reinforced polyoxymethylene (POM) acetal copolymer. It synthesizes data from multiple sources to detail its mechanical, thermal, electrical, and physical properties. Key analyses include a direct comparison against the unfilled C 9021 base grade to quantify the effects of reinforcement, positioning within the broader glass-filled POM portfolio, and a thorough review of processing guidelines, application suitability, regulatory status, and safety considerations. The document is intended to serve as a primary technical resource for engineers and designers evaluating this material for demanding applications requiring high strength, stiffness, and dimensional stability.
Introduction and Material Profile
Grade Overview and Designation
Hostaform® C 9021 GV1/10 is a specialized, high-performance engineering thermoplastic supplied by Celanese Corporation. It is an injection molding grade based on a polyoxymethylene (POM) copolymer matrix, which is distinguished by the inclusion of approximately 10% short glass fibers by weight as reinforcement. This composite structure is engineered to deliver a specific balance of properties tailored for demanding applications.
ISO Classifications
- Chemical Abbreviation (ISO 1043-1):
POM - Molding Compound (ISO 29988):
POM-K, M-GNR, 02-003, GF10
The core value proposition of Hostaform® C 9021 GV1/10 is its ability to produce molded parts with significantly enhanced mechanical properties, specifically high strength and rigidity. The glass fiber reinforcement also imparts improved dimensional stability by reducing thermal expansion and molding shrinkage compared to its unfilled counterpart. To facilitate manufacturing, the formulation includes a mold release agent.
Positioning within the Hostaform® Portfolio
Hostaform® C 9021 GV1/10 serves as a foundational reinforced grade, representing a significant step-up in mechanical performance from the widely used unfilled base grade, C 9021. It is the entry point into the glass-reinforced series, which extends to more heavily filled grades such as C 9021 GV1/20 (20% glass fiber) and C 9021 GV1/30 (approximately 26% glass fiber).
This positioning is critical from an engineering perspective. It occupies a "sweet spot" for applications that require stiffness and strength beyond the capabilities of unfilled POM but do not warrant the extreme rigidity, higher cost, and potential processing challenges associated with the more heavily reinforced grades.
Comprehensive Material Properties
Mechanical Performance
The inclusion of glass fibers fundamentally alters the material's response to applied stress, resulting in a stiffer, stronger, but less ductile material.
Key Mechanical Strengths
Impact Strength (Charpy, Unnotched)
| Property | Value | Unit | Test Standard |
|---|---|---|---|
| Tensile Modulus | 4800 | MPa | ISO 527-1/-2 |
| Stress at Break | 90 | MPa | ISO 527-1/-2 |
| Strain at Break | 4 | % | ISO 527-1/-2 |
| Flexural Modulus | 4500 | MPa | ISO 178 |
| Flexural Strength | 130 | MPa | ISO 178 |
| Tensile Creep Modulus (1000h) | 2500 | MPa | ISO 899-1 |
| Charpy Notched Impact Strength (23°C) | 6.5 | kJ/m² | ISO 179/1eA |
| Ball Indentation Hardness | 170 | MPa | ISO 2039-1 |
Thermal Characteristics
Thermal Performance
| Property | Value | Unit | Test Standard |
|---|---|---|---|
| Melting Temperature (10°C/min) | 166 | °C | ISO 11357-1/-3 |
| Temp. of Deflection Under Load (DTUL) @ 1.8 MPa | 154 | °C | ISO 75-1/-2 |
| Temp. of Deflection Under Load (DTUL) @ 8.0 MPa | 64 | °C | ISO 75-1/-2 |
| Coeff. of Linear Thermal Expansion, parallel | 80 | 10-6/K | ISO 11359-1/-2 |
Electrical Insulation Properties
Hostaform® C 9021 GV1/10 retains the excellent electrical insulating properties characteristic of the POM family, making it suitable for electromechanical components. Its Comparative Tracking Index (CTI) of 600 V (PLC 0) is a key feature for safety in electrical applications.
Physical and Rheological Data
A critical aspect revealed by this data is the material's anisotropy due to fiber alignment during molding. This affects shrinkage and thermal expansion, which must be considered in part design.
Performance in Context: A Comparative Analysis
The Impact of 10% Glass Fiber: C 9021 GV1/10 vs. C 9021 (Unfilled)
The addition of 10% glass fiber transforms the material's character from a tough, ductile polymer to a stiff, structural composite.
Performance Boost: Reinforced vs. Unfilled
| Property | C 9021 GV1/10 (10% GF) | C 9021 (Unfilled) | % Change |
|---|---|---|---|
| Tensile Modulus (MPa) | 4800 | 2850 | +68% |
| Stress at Yield/Break (MPa) | 90 (Break) | 64 (Yield) | +41% |
| Nominal Strain at Break (%) | 4 | 30 | -87% |
| DTUL @ 1.8 MPa (°C) | 154 | 104 | +48% |
| Molding Shrinkage, parallel (%) | 1.4 | 2.0 | -30% |
The analysis is stark: stiffness and high-temperature load-bearing capacity are dramatically increased, at the cost of a drastic reduction in ductility. This makes C 9021 GV1/10 superior for static, load-bearing applications.
Positioning within the Glass-Reinforced Portfolio
Tensile Modulus vs. Glass Fiber Content
As glass fiber content increases across the portfolio (GV1/10, GV1/20, GV1/30), stiffness and strength rise predictably. C 9021 GV1/10 is the logical first step for designers needing a performance boost over unfilled grades without the cost and processing challenges of highly-filled materials.
Application and Environmental Performance
Target Applications and Use Cases
Industrial & Automotive
Load-bearing housings, support brackets, levers, pump components, electrical connectors.
Precision Engineering
Gears and meter components requiring tight tolerances and dimensional stability.
Metal Replacement
Viable candidate for replacing die-cast metals like zinc and aluminum for weight reduction.
Chemical Resistance Profile
Hostaform® POM copolymers are known for their broad chemical resistance to substances like dilute acids, strong alkalis, fuels, oils, and solvents. However, long-term exposure to liquids can affect the fiber-polymer interface, a key consideration for parts in long-term fluid contact.
UV and Weathering Resistance
Important: Standard POM grades, including Hostaform® C 9021 GV1/10, are not inherently resistant to ultraviolet (UV) radiation and are not recommended for unprotected outdoor applications.
Manufacturing and Processing Guidelines
Injection Molding Protocol
The combination of a "slow" injection speed and a high mold temperature (80-120 °C) is critical for achieving optimal properties, maximizing crystallinity, and minimizing internal stress.
| Parameter | Recommended Value | Unit |
|---|---|---|
| Drying Temperature | 100 - 120 | °C |
| Drying Time (Dehumidified Dryer) | 3 - 4 | h |
| Melt Temperature | 190 - 210 | °C |
| Mold Temperature | 80 - 120 | °C |
| Injection Speed | Slow | - |
Regulatory and Compliance Status
- Flammability: UL 94 HB rating.
- Automotive: Meets FMVSS 302 and is compliant with BOSCH N28 BN22-X006.
- Food Contact (FDA/EU): Compliance is not declared for this specific grade. Direct verification from Celanese is mandatory for food/potable water applications.
Health and Safety Synopsis
Processing requires adherence to standard industrial safety practices. Key hazards include thermal burns from molten polymer and inhalation of decomposition fumes (formaldehyde) if overheated.
Primary Hazards
- Thermal Hazard: Molten polymer (190-210 °C) causes severe burns.
- Inhalation Hazard: Overheating above 238 °C generates hazardous formaldehyde vapors.
- Material Incompatibility: Do not mix with PVC or halogen-containing polymers.