Ready Plastics

Acetal Copolymer Grades — Celcon, Hostaform & Ultraform Compared

Acetal copolymer (POM-C) is produced by multiple manufacturers under different brand names: Celcon (Celanese), Hostaform (Ticona/Celanese), Ultraform (BASF), and Tenac-C (Asahi Kasei). Each brand offers a grade series covering standard, lubricated, glass-fiber reinforced, heat-stabilized, UV-stabilized, and FDA-compliant formulations. This guide maps the key grades across brands, explains what differentiates them, and provides the selection logic for engineering and procurement.

At a glance:

  • Standard grades: Celcon M90 / Hostaform C 9021 — the workhorse injection molding grades
  • Extrusion (stock shape) grades: Celcon M25 / Hostaform C 52021 (glass-filled) / high-MW grades
  • Lubricated grades: Celcon M90-44 / Hostaform C 9021 XAP2 — lower CoF for bearing/sliding use
  • Glass-fiber reinforced: Hostaform C 52021 (25% GF); Celcon GF25 — 15,000+ psi tensile
  • Heat-stabilized: Hostaform C 9021 HS; Celcon heat-stabilized grades — for hot-water service
  • FDA grades: natural-color standard Celcon M90 and Hostaform C 9021 generally compliant (verify lot)

Brand Overview

Celcon (Celanese)

Celcon is the flagship POM-C brand from Celanese Corporation, the world's largest acetal producer. The grade numbering system uses viscosity (molecular weight) index: M25 is high-viscosity/high-MW (suited for extrusion), M90 is medium-viscosity (standard injection molding), and M270 is low-viscosity (thin-wall, fast-cycle molding). Suffix letters indicate modifications: no suffix = unfilled standard; GF = glass-fiber; SP = special stabilization; ST = antistatic.

For the full Celcon grade matrix, see the dedicated Celcon grades page.

Hostaform (Ticona/Celanese)

Hostaform is the European trade name for Celanese POM-C — the same polymer chemistry, the same production plants, different branding for the European and Asian markets. Hostaform grades use a different numbering system: C 9021 (standard injection molding), C 13021 (general purpose), C 52021 (glass-fiber reinforced), and modifier suffixes (XAP2 = lubricated; HS = heat-stabilized; UV = UV-stabilized).

For the full Hostaform grade matrix, see the dedicated Hostaform grades page.

Ultraform (BASF)

Ultraform is BASF's acetal copolymer brand. Standard grades include Ultraform N 2320 (standard injection molding, equivalent to M90/C 9021) and Ultraform W 2320 (modified). BASF Ultraform material appears in some European-sourced stock shapes and is specified in some German automotive standards by name.

Tenac-C (Asahi Kasei)

Tenac-C is Asahi Kasei's POM-C brand. Key differentiator: low formaldehyde emission, achieved through proprietary end-capping and stabilizer systems. Tenac-C is widely specified in Japanese automotive interior applications subject to JAMA VOC regulations. Available in standard, lubricated, and reinforced grades.

Standard Grade Comparison Across Brands

High-Viscosity / Extrusion Grades

Stock-shape rod, sheet, and tube are produced by extrusion — a process that requires higher polymer melt viscosity than injection molding. The following grades are optimized for extrusion or are the grades most commonly used in extruded stock shapes:

Celcon M25: Higher molecular weight than M90; better suited for extrusion into rod and sheet. Produces a more uniform cross-section in large diameters. Mechanical properties are slightly higher than M90 due to higher MW.

Hostaform C 13021: Celanese's general-purpose extrusion/molding grade in the Hostaform line; equivalent to a mid-point between C 9021 and higher-MW grades.

Generic POM-C stock: Many stock-shape distributors source extruded rod and sheet from undisclosed POM-C grades that meet ASTM D6100 property requirements without specifying a brand grade. This is acceptable for most applications; request a certificate of conformance to ASTM D6100 rather than specifying a brand grade if brand traceability is not required.

Lubricated Grades

Lubricated acetal copolymer grades incorporate internal lubricant additives — typically PTFE, silicone oil, or proprietary lubricant compounds — to reduce surface friction and improve wear life in sliding applications.

Celcon M90-44: Celcon's lubricated injection molding grade. CoF vs. steel reduced to approximately 0.10–0.20 vs. 0.20–0.35 for standard M90.

Hostaform C 9021 XAP2: Hostaform's lubricated grade with a proprietary additive system. Similar CoF improvement; used in automotive fuel-system and window-mechanism applications where external lubrication is not practical.

Key trade-offs of lubricated grades:

  • Tensile strength is modestly reduced (~5–10%) vs. standard grade
  • Adhesive bonding and welding are more difficult due to lubricant migration to the surface
  • Not FDA-compliant in most formulations (lubricant additives may not be CFR-listed)
  • Print marking and painting are more difficult for the same surface-energy reasons

Glass-Fiber Reinforced Grades

Glass-fiber reinforced POM-C is less common in stock shapes than in injection molding compounds; it is available from some stock-shape suppliers in rod and sheet for applications requiring the higher stiffness and creep resistance. Machining considerations are the same as for Delrin 570 (GF): carbide tooling required, accelerated tool wear, PCD inserts for production volume.

Heat-Stabilized Grades

Standard POM-C grades (M90, C 9021) are rated for water contact up to approximately 80°C continuous. Heat-stabilized grades extend this to ~90–95°C by incorporating proprietary thermal stabilizer packages that inhibit oxidative chain scission at elevated temperatures.

Hostaform C 9021 HS: Celanese/Ticona's heat-stabilized grade for extended hot-water service. Used in European dishwasher and heating system components.

Celcon heat-stabilized variants: Available through the Celcon HS grade family; verify current nomenclature with Celanese technical support.

Applications requiring heat-stabilized grades:

  • Dishwasher spray arms and pump housings subject to 160°F (71°C) wash water
  • Hot-water circulation system components in heating and plumbing
  • Automotive cooling system parts adjacent to the engine coolant circuit
  • Coffee machine internals exposed to near-boiling water continuously

UV-Stabilized Grades

Standard POM-C degrades under UV exposure: surface chalking, yellowing, and eventual embrittlement occur with prolonged outdoor exposure. UV-stabilized grades incorporate UV absorbers or hindered amine light stabilizers (HALS).

Hostaform C 9021 UV: Celanese's UV-stabilized POM-C for outdoor applications. Service life extension in direct sunlight is 3–5× vs. standard grade.

Applications: Outdoor irrigation controls, garden tool components, automotive exterior trim clips, and outdoor electrical enclosure latches.

FDA-Compliant Grades

Unlike Delrin, which designates specific "SA" grades for food-contact compliance, many standard natural-color Celcon and Hostaform grades meet FDA 21 CFR 177.2480 because the base polymer and stabilizer package are generally composed of FDA-listed substances. However, this is not universal — some specialty formulations use non-CFR-listed components.

Verification approach:

  • Request FDA compliance letter or CFR 177.2480 compliance statement with each lot
  • Natural (white) color grades are most reliably compliant; black and colored grades may use non-FDA-listed pigments
  • NSF 51 and NSF 61 certified grades are available from Celcon and Hostaform; verify the specific grade and lot

For full details on FDA-compliant grades and food-contact certification, see acetal copolymer FDA food-grade compliance.

Grade Selection Logic

  1. General-purpose machined parts from stock → Standard POM-C (any brand natural grade meeting ASTM D6100)
  2. Injection-molded parts, standard duty → Celcon M90 or Hostaform C 9021
  3. Hot-water service (>80°C) → Celcon HS or Hostaform C 9021 HS (heat-stabilized)
  4. Bearing/sliding parts with low friction requirement → Celcon M90-44 or Hostaform C 9021 XAP2 (lubricated)
  5. Maximum stiffness and creep resistance → Hostaform C 52021 or Celcon GF25 (glass-filled)
  6. Outdoor / UV-exposed applications → Hostaform C 9021 UV or equivalent UV-stabilized grade
  7. FDA food contact required → Natural color grade with CFR 177.2480 compliance letter
  8. Low formaldehyde emission (automotive interior) → Tenac-C or Celanese low-emission variants
  9. Large-diameter stock shapes → Standard POM-C rod (high-MW/extrusion grade if available)

Order acetal copolymer in the grade you need — rod, sheet, tube

Request a Quote →

More related guides

Compare to other materials

Brand grade pages

Frequently asked questions — Acetal Copolymer FAQ