Crastin SK605: specs and equivalent grades
Celanese 30% glass-reinforced, lubricated PBT for injection molding, sold as SK605 NC010 (natural). Published data, grades from other producers to ask about, and how to request a quote from one gaylord.
Request a QuoteThe short answer
Crastin SK605 is a 30% glass fiber reinforced, lubricated polybutylene terephthalate (PBT GF30) for injection molding. Celanese has sold Crastin since it bought most of DuPont’s Mobility & Materials business in November 2022, so older paperwork may still say DuPont. The Celanese data sheet for SK605 NC010 lists density 1.53 g/cm³ (ISO 1183), MFR 10 g/10 min at 250°C / 482°F, 2.16 kg (ISO 1133) and HDT 205°C / 401°F at 1.8 MPa (ISO 75). Grades from other producers to ask about include Valox 420, Ultradur B4300 G6 and Pocan B3235. They are not identical, so compare the data sheets and run a trial before switching.
Also written as: Crastin SK605 NC010 (natural), Crastin SK605 BK851 (black). Quote the full code from your drawing or bag label; color and additive suffixes change the grade.
Buying Crastin SK605: one gaylord to a railcar · supplier COA on every prime lot · ships from 22+ partner warehouse locations · a polymer chemist checks the grade code before we quote · we aim to quote within one to three business days
Have a part number or drawing callout?
Paste it as written. A polymer chemist will tell you which grade it calls for, suggest equivalents and quote it by email.
Crastin SK605 specs from the data sheet
Typical values checked against Celanese’s Chemille database on October 31, 2026, from the Celanese data sheet for Crastin SK605 NC010 (source: Celanese Materials Database, revised July 13, 2024). Typical values are not specifications; the lot COA shows what you actually receive. Values only compare at the same test method and condition.
| Property | Value | Test method or note |
|---|---|---|
| Producer (brand owner) | Celanese (a DuPont brand until November 2022) | Celanese data sheet |
| Polymer | PBT, 30% glass fiber, lubricated (release agent) | ISO 1043: PBT-GF30 |
| Process | Injection molding | |
| Density | 1.53 g/cm³ | ISO 1183 |
| Melt flow | MFR 10 g/10 min; MVR 7 cm³/10 min | 250°C / 482°F, 2.16 kg, ISO 1133 |
| Tensile modulus | 10,000 MPa (1,450,000 psi) | ISO 527-1/-2 |
| Tensile stress at break | 140 MPa (20,300 psi) | ISO 527-1/-2, 5 mm/min |
| Tensile strain at break | 2.7% | ISO 527-1/-2, 5 mm/min |
| Flexural modulus | 9,000 MPa (1,310,000 psi) | ISO 178 |
| Flexural strength | 200 MPa (29,000 psi) | ISO 178 |
| Charpy notched impact | 10 kJ/m² at 23°C; 11 kJ/m² at -30°C; 10 kJ/m² at -40°C | ISO 179/1eA |
| Izod notched impact | 11 kJ/m² at 23°C | ISO 180/1A |
| Melting temperature | 225°C / 437°F | ISO 11357-1/-3, 10°C/min |
| HDT at 1.8 MPa | 205°C / 401°F | ISO 75-1/-2 |
| HDT at 0.45 MPa | 220°C / 428°F | ISO 75-1/-2 |
| Molding shrinkage | 0.3% parallel; 1.1% normal | ISO 294-4 |
| Water absorption | 0.35% in water; 0.15% humidity (2 mm) | Similar to ISO 62 |
| Relative thermal index | 130°C / 266°F electrical, impact and strength, 0.75–6 mm | UL 746B |
| Flame rating | HB at 0.75 mm and 1.5 mm, UL recognized | IEC 60695-11-10; UL 94 |
| Comparative tracking index | 400 | IEC 60112 |
| Drying | 120°C / 248°F for 2–4 h in a dehumidified dryer; 0.04% maximum moisture | Celanese data sheet |
| Melt temperature | 240–260°C / 464–500°F; 250°C / 482°F optimum | Celanese data sheet |
| Mold temperature | 30–130°C / 86–266°F; 80°C / 176°F optimum | Celanese data sheet |
| Food contact | No food-contact statement on the data sheet | Ask for the producer’s regulatory letter |
Source data sheets are listed at the bottom of this page. Confirm against the current sheet for your exact grade code and color.
Celanese’s processing moisture limit (0.04%) is looser than the 0.02% on SABIC’s Valox 420 sheet. If you qualify one against the other, dry to the stricter number.
Grades to ask about instead of Crastin SK605
These grades from other producers have similar published specs. None is a drop-in replacement: additive packages, flow at molding shear rates, color and approvals differ. If your part, drawing or customer approval names Crastin SK605, any change needs your approval and usually a trial.
| Grade | Producer | Melt flow | Density | Key property | How it compares |
|---|---|---|---|---|---|
| Valox 420 | NexPoint Materials (former SABIC) | MFR 17 g/10 min; MVR 13 cm³/10 min (250°C / 482°F, 2.16 kg, ISO 1133) | 1.53 (specific gravity, ASTM D792) | HDT 204°C at 1.8 MPa (ISO 75); tensile strength 125 MPa (ISO 527); RTI 140°C (UL 746) | Close match. Same glass level and density with higher flow (MVR 13 vs 7 at the same condition). Higher RTI (140°C vs 130°C) but lower CTI (300 V vs 400). The Americas sheet we found dates from 2013; ask for the current NexPoint sheet. Quote this alternative › |
| Ultradur B4300 G6 | BASF | MVR 11 cm³/10 min (250°C / 482°F, 2.16 kg, ISO 1133) | 1.53 g/cm³ (ISO 1183) | HDT 205°C at 1.8 MPa (ISO 75); tensile modulus 9,800 MPa; stress at break 140 MPa | Close match. Same HDT and stress at break, slightly higher flow (MVR 11 vs 7). BASF lists a 250–275°C melt and a 60–100°C mold, a little hotter than Crastin’s 240–260°C melt. Quote this alternative › |
| Pocan B3235 | Envalior | MVR 17 cm³/10 min (260°C / 500°F, 2.16 kg, ISO 1133) | 1.53 g/cm³ (ISO 1183) | HDT 210°C at 1.8 MPa (ISO 75); stress at break 145 MPa; Charpy notched 10 kJ/m² | Close match on mechanicals. Flow is measured at 260°C, not 250°C, so it does not compare directly with Crastin’s MVR. Envalior recommends an 80–100°C mold and 4–8 h drying at 120°C. Quote this alternative › |
From each producer’s published data. Brand owners and grade names change; confirm on the current data sheet.
Typical uses for Crastin SK605
Celanese’s data sheet lists no specific parts for SK605. It describes Crastin PBT in general as used in demanding applications in these industries:
- Electronics and electrical
- Automotive
- Mechanical engineering
- Chemical
- Domestic appliances
- Sporting goods
What to check before you switch
- Older approvals, COAs and UL files may say DuPont. Celanese has owned Crastin since November 2022; ask for the current Celanese data sheet and UL file with your quote.
- Crastin SK605 is lubricated with a release agent. If an alternative uses a different package, check ejection, mold deposit and any painting, printing or bonding downstream.
- Crastin SK605 has the lowest flow of the PBT GF30 grades on this page (MVR 7). Higher-flow alternatives can change pack pressure, flash and shrink.
- Compare at the same test standard. Celanese data is ISO; SABIC’s Valox sheet is mostly ASTM.
- For electrical parts, check RTI (130°C on the Crastin sheet) and CTI (400) against your UL requirements.
- Ask for the producer’s food-contact or regulatory letter for the exact grade if the part needs one.
- Run a trial lot and check shrinkage, cycle time and appearance before you switch production.
Buying Crastin SK605: price, lead time and lot size
- Lot size. From one gaylord to a railcar. See gaylord, LTL and truckload for typical weights per box.
- Where it ships from. 22+ partner warehouse locations. Material already in a partner warehouse usually moves sooner than a grade that has to come from the producer; your quote says which applies.
- Price. We do not publish prices because they move with feedstock, freight and order size. What moves your price most: lot size, color, ship-to region, and whether you need Crastin SK605 itself or can accept a matched alternative. See how resin is priced and the monthly market update.
- Paperwork. Supplier COA on every prime lot (what a COA shows). Ask for the producer’s regulatory letter or UL file if your part needs them.
- Trying an alternative? Start with one gaylord as a trial lot, molded and checked before you commit a full release.
- If Crastin SK605 itself is not available. Some branded grades are sold only through the producer’s own channels or go on allocation. If we cannot source it, we tell you, then quote a matched alternative with a side-by-side comparison.
Send the grade code, your annual volume and ship-to location. A polymer chemist checks it before we quote; we have been in the resin business for 30+ years. For several grades at once, use the resin RFQ template.
Trade names belong to their owners. ResinBridge is not affiliated with these producers; grade names are used only to identify the material. Data reflects published sheets as of October 2026.
Sources
- Celanese Chemille database: Crastin SK605 NC010 (producer data, checked Oct 31, 2026)
- Celanese Crastin SK605 NC010 data sheet, revised July 13, 2024 (PDF copy)
- Plastics Technology: Celanese to acquire DuPont engineering plastics (Feb 2022)
- SABIC VALOX 420 Americas technical data sheet, UL Prospector form TDS-4725 (PDF)
- BASF Ultradur B 4300 G6 product information, 09/2026 (PDF)
- Envalior Pocan B3235 data sheet from Material Data Center (PDF)
Common questions
What is Crastin SK605?
Crastin SK605 is a 30% glass fiber reinforced, lubricated PBT for injection molding, sold by Celanese as SK605 NC010 (natural). It was a DuPont brand until Celanese bought most of DuPont’s Mobility & Materials business in November 2022.
What is the melt flow of Crastin SK605?
MFR 10 g/10 min and MVR 7 cm³/10 min, both at 250°C / 482°F, 2.16 kg, ISO 1133, per the Celanese data sheet for SK605 NC010.
What is equivalent to Crastin SK605?
Grades from other producers to ask about include Valox 420, Ultradur B4300 G6 and Pocan B3235. None is identical; compare data sheets and run a trial, and get approval if your part names Crastin SK605.
How do you dry Crastin SK605?
Celanese gives 120°C / 248°F for 2–4 hours in a dehumidified dryer, to 0.04% moisture or less.
Can ResinBridge supply Crastin SK605?
We quote Crastin SK605 when our supply partners can source it. If they cannot, we say so up front and quote a matched alternative, named on the quote with its data sheet, so you can decide whether to trial it.
If your grade is not listed, tell us what you run. We source commodity, engineering and specialty resins.
Need Crastin SK605 or an equivalent?
A polymer chemist reviews every request, then matches your grade or finds a matched alternative and prices it.
What to send for an accurate quote
- The grade name, from any supplier, or a data sheet
- Color (natural, black or a custom match)
- Fill type and percentage, if any
- Melt flow, if you know it
- Quantity for this order and what you use in a year
- Ship-to city and state or province
Quote Crastin SK605 or a matched alternative
A polymer chemist checks the data sheet and tells you exactly what you would get before you order.
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