Pro-fax 6331: specs and equivalent grades
LyondellBasell general purpose polypropylene homopolymer for injection molding, sold in North America. Published data, grades from other producers to ask about, and how to request a quote from one gaylord.
Request a QuoteThe short answer
Pro-fax 6331 is LyondellBasell's general purpose polypropylene homopolymer, sold in pellet form mainly for injection molding (LyondellBasell also lists cast film and compounding) and available in North America. Published melt flow is 12 g/10 min, measured at 230°C / 446°F, 2.16 kg, ASTM D1238, and density is 0.90 g/cm³ (ASTM D792). Grades from other producers to ask about include ExxonMobil PP1024E4, Formolene 4100N and TotalEnergies Polypropylene 3620WZ. They are not identical, so compare the data sheets and run a trial before switching.
Buying Pro-fax 6331: 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.
Pro-fax 6331 specs from the data sheet
Typical values from LyondellBasell's published data sheet. 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) | LyondellBasell | Data sheet |
| Polymer | Polypropylene homopolymer, general purpose | |
| Process | Injection molding; LyondellBasell also lists cast film and compounding | |
| Availability | North America (status: commercial, active) | Data sheet |
| Melt flow | 12 g/10 min | 230°C / 446°F, 2.16 kg, ASTM D1238 |
| Density | 0.90 g/cm³ (ASTM D792) | |
| Flexural modulus, 1% secant | 1,450 MPa (210,000 psi) | ASTM D790, Procedure A, 1.3 mm/min (0.05 in/min) |
| Tensile strength at yield | 34 MPa (4,900 psi) | ASTM D638, 50 mm/min (2 in/min) |
| Tensile elongation at yield | 11 % | ASTM D638 |
| Notched Izod impact, 23°C / 73°F | 32 J/m (0.6 ft-lb/in) | ASTM D256, Method A |
| HDT 0.45 MPa (66 psi), unannealed | 93°C / 200°F | ASTM D648 |
| Additives | None stated (listed as general purpose) | |
| Food contact | The data sheet makes no food-contact statement; it refers to LyondellBasell's Product Stewardship Bulletin (PSB), a separate document from LyondellBasell. LyondellBasell lists food packaging film among its applications. Ask for the PSB or a regulatory letter for your use. | |
| Melt temperature range | Not published on the data sheet | LyondellBasell TDS (publication date 10/31/2026): 'Specific recommendations for resin type and processing conditions can only be made when the end use, required properties and fabrication equipment are known.' |
| Mold temperature range | Not published on the data sheet | LyondellBasell TDS |
| Drying | No drying step on the data sheet. LyondellBasell's polyolefin film extrusion guide (linked from the product page) says polyolefins are non-hygroscopic and do not need drying before extrusion | LyondellBasell 'A Guide to Polyolefin Film Extrusion' |
| Form and packaging | Pellets. Package sizes not published | LyondellBasell TDS product description ('available in pellet form') |
Source data sheets are listed at the bottom of this page. Confirm against the current sheet for your exact grade code and color.
LyondellBasell's polyolefin film extrusion guide, linked from this grade's product page, says polyolefins are non-hygroscopic and do not need drying before extrusion; the grade's own data sheet gives no drying or temperature settings.
Grades to ask about instead of Pro-fax 6331
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 Pro-fax 6331, any change needs your approval and usually a trial.
| Grade | Producer | Melt flow | Density | Key property | How it compares |
|---|---|---|---|---|---|
| ExxonMobil PP1024E4 | ExxonMobil | 13 g/10 min (230°C / 446°F, 2.16 kg, ASTM D1238) | 0.900 g/cm³ (ASTM D1505) | Flexural modulus, 1% secant 1,370 MPa (198,000 psi) (ASTM D790A); notched Izod 27 J/m (ASTM D256A) | Close match. General purpose injection molding homopolymer for North America. MFR about 8% higher than 6331 and slightly lower stiffness. ExxonMobil does not allow medical use or testing without its written acknowledgement and asks buyers to contact it for food-contact compliance. See our ExxonMobil PP1024E4 page. Quote this alternative › |
| Formolene 4100N | Formosa Plastics USA | 12 g/10 min (230°C / 446°F, ASTM D1238) | 0.9 g/cm³ (ASTM D1505) | Flexural modulus, 1% secant 1,371 MPa (200,000 psi) (ASTM D790); notched Izod 27 J/m (0.5 ft-lb/in) (ASTM D256A) | Close match. Medium viscosity homopolymer for general purpose injection molding (closures, small appliances, housewares, toys). Same MFR as 6331. Formosa states it meets FDA 21 CFR 177.1520. HDT at 66 psi is listed as 100°C / 212°F. Quote this alternative › |
| TotalEnergies Polypropylene 3620WZ | TotalEnergies (produced in the United States) | 12 g/10 min (ASTM D1238, Condition L: 230°C, 2.16 kg) | 0.905 g/cm³ (ASTM D1505) | Flexural modulus 1,585 MPa (230,000 psi) (ASTM D790); notched Izod 27 J/m (0.5 ft-lb/in) (ASTM D256A) | Partial match. Same MFR, but 3620WZ is nucleated and contains antistat, for fast cycles and contact clarity in thin wall multi-cavity molds (caps, closures, medical syringes, thin wall containers). Stiffer than 6331, with HDT at 66 psi of 127°C / 260°F. TotalEnergies states it has passed USP Class VI testing and complies with applicable FDA food contact regulations. Quote this alternative › |
From each producer's published data. Brand owners and grade names change; confirm on the current data sheet.
Typical uses for Pro-fax 6331
Applications, markets and processing methods listed on LyondellBasell's data sheet:
- Caps and closures
- Containers
- Food packaging film
- Consumer products
- Flexible and rigid packaging
- Compounding
What to check before you switch
- 6331 is listed as general purpose with no nucleator or antistat. TotalEnergies 3620WZ is nucleated and antistatic, so it shrinks and sets up differently; check part dimensions and cycle time.
- HDT at 66 psi differs across these grades: 93°C / 200°F (6331), 90.6°C / 195°F (PP1024E4), 100°C / 212°F (Formolene 4100N) and 127°C / 260°F (3620WZ). Check parts that see heat under load.
- LyondellBasell keeps regulatory details in its Product Stewardship Bulletin, a separate document from the data sheet. Ask for the PSB or a letter if your part contacts food.
- ExxonMobil PP1024E4 may not be used or tested in medical applications without ExxonMobil's written acknowledgement. Check this before you move a medical part.
- Compare melt flow, density and impact only at the same test condition and method (ASTM vs. ISO results differ).
- 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 Pro-fax 6331: 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 Pro-fax 6331 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 Pro-fax 6331 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
- LyondellBasell Pro-fax 6331 product page
- LyondellBasell Pro-fax 6331 technical data sheet (PDF)
- ExxonMobil PP1024E4 data sheet (PDF)
- Formosa Formolene 4100N data sheet (PDF)
- TotalEnergies Polypropylene 3620WZ data sheet (PDF)
- LyondellBasell: A Guide to Polyolefin Film Extrusion (PDF)
Common questions
What is Pro-fax 6331?
Pro-fax 6331 is LyondellBasell's general purpose polypropylene homopolymer, sold in pellet form mainly for injection molding (LyondellBasell also lists cast film and compounding) and available in North America.
What is the melt flow of Pro-fax 6331?
12 g/10 min, measured at 230°C / 446°F, 2.16 kg, ASTM D1238, per the published data sheet.
What is equivalent to Pro-fax 6331?
Grades from other producers to ask about include ExxonMobil PP1024E4, Formolene 4100N and TotalEnergies Polypropylene 3620WZ. None is identical; compare data sheets and run a trial, and get approval if your part names Pro-fax 6331.
Is Pro-fax 6331 food-contact compliant?
The data sheet makes no food-contact statement; it refers to LyondellBasell's Product Stewardship Bulletin (PSB), a separate document from LyondellBasell. LyondellBasell lists food packaging film among its applications. Ask for the PSB or a regulatory letter for your use.
Can ResinBridge quote Pro-fax 6331?
Yes. Send the grade name and volume. A polymer chemist checks it and we quote the grade where we can source it, or a matched alternative, and say which one. Orders start at one gaylord; U.S. and Canada only.
If your grade is not listed, tell us what you run. We source commodity, engineering and specialty resins.
Need Pro-fax 6331 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 Pro-fax 6331 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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