The short answer
Clarified PP random copolymer is polypropylene with a few percent ethylene in the chain plus a clarifying agent. It gives the clearest PP, a lower melting point (about 140–150°C / 284–302°F, against 160–165°C / 320–329°F for homopolymer) and less stiffness. Grades run about 1–4 g/10 min MFR at 230°C / 2.16 kg for extrusion, thermoforming and blow molding, about 10–35 for injection, and higher for thin-wall cups and lids. Order it as clarified, with the MFR and haze at a stated thickness.
This page covers clarified random copolymer. To compare the three PP types, see PP homopolymer and impact copolymer. For other clear resins, see best plastic for clear parts.
Typical spec window
| Property | Typical range | Test method |
|---|---|---|
| Melt flow rate | About 1–4 g/10 min for extrusion, thermoforming and blow molding; about 10–35 for injection; about 35–100+ for thin wall | ASTM D1238 or ISO 1133, 230°C / 2.16 kg |
| Ethylene content | A few percent; seldom given as a spec | Stated by the producer |
| Density | About 0.90 g/cm³ | ASTM D792 or ISO 1183 |
| Melting point | About 140–150°C / 284–302°F | DSC, ASTM D3418 or ISO 11357-3 |
| Haze | Grade- and thickness-specific; compare at the same plaque thickness | ASTM D1003 |
| Flexural modulus | Lower than homopolymer; compare on the data sheet | ASTM D790 or ISO 178 |
Typical ranges from published data sheets for grades in this window. Your grade’s own data sheet and the lot COA are what count.
What it’s used for
- Clear storage boxes and bins
- Deli and food containers, cups and lids
- See-through housewares
- Extrusion blow-molded bottles and thermoformed packaging (low-MFR grades)
- Medical and pharmaceutical uses depend on documents the producer issues for that exact grade. See FDA and medical grades.
How to tell grades apart
- Clarified or plain. The clarifier makes the big difference in haze. A plain random copolymer is translucent, so the two are not interchangeable.
- MFR. Set by the process: low for extrusion and thermoforming, mid for injection, high for thin-wall cups and lids.
- Ethylene content. More ethylene gives a clearer, softer part with a lower melting point.
- Wall thickness. Haze rises as walls get thicker. A cooler mold and thinner walls usually give a clearer part.
- Antistatic. Keeps clear boxes from showing dust on the shelf.
- Odor and taste. Overheating a clarified grade can raise odor and taste. Ask about both if you package food or water.
What to put on your RFQ or PO
- The type, in words. Random copolymer, clarified.
- MFR with the condition. At 230°C / 446°F and 2.16 kg, nominal value and spec range.
- Clarity. Haze by ASTM D1003 at a stated thickness, or approval on your own parts.
- Stiffness. A flexural modulus range, so lids and walls stay rigid.
- Additives. Clarifier, antistatic, UV or slip, as the part needs.
- Color. Clear natural, or a tint and its masterbatch.
- Food contact. The producer’s FDA letter for the exact grade; PP letters usually cite 21 CFR 177.1520.
- COA values to check. MFR on every lot.
- Packaging, quantity and release size. Gaylords, 25 kg (55 lb) bags, bulk truck or railcar; the total, the amount per release and how often.
A polymer chemist reviews every request and checks the grade against your process before we quote. Every prime lot from our suppliers ships with a COA, and orders start at one gaylord.
Get an email when resin prices move
A short note when PP, PE, nylon or other prices shift. No spam; unsubscribe anytime.
By signing up you agree to receive emails from ResinBridge. Unsubscribe anytime by replying or using the link in any email. PrivacyEquivalents and substitutes
- Another clarified random copolymer at the same MFR. The closest swap. Compare haze on molded parts, not only on the sheet.
- Clarified homopolymer. Stiffer and more heat resistant, but less clear.
- Metallocene random PP. Can give lower haze and extractables. See metallocene PE and PP.
- PET, polystyrene, SAN or polycarbonate. For glass-like clarity, with different processing and chemical resistance.
- Impact copolymer. Not a clear option; the rubber phase makes it opaque.
Common processing problems
- Visible flow marks in clear parts: flow lines
- Bow and twist: warped parts
- Yellow or off-color parts: heat discoloration
- Parts that hang up on the core: parts sticking in the mold
- Food-contact paperwork: need FDA food contact
Common questions
What is clarified polypropylene?
It is PP, usually a random copolymer, with a clarifying agent that makes the crystals small enough to scatter less light. The result is near-transparent in thin walls.
How clear is PP random copolymer?
Clarified grades are near-transparent in thin walls, and haze rises as walls get thicker. They do not match PET, polystyrene or polycarbonate for glass-like clarity. Compare grades by haze at the same thickness (ASTM D1003).
What MFR random copolymer should I use?
About 1–4 g/10 min at 230°C / 2.16 kg for extrusion, thermoforming and blow molding, about 10–35 for general injection molding, and higher for thin-wall cups and lids. Match the grade you run now, then check clarity on real parts.
Is random copolymer PP food safe?
Many grades are made for food contact, but compliance belongs to the grade, not the family. Ask for the producer’s FDA letter for the exact grade, and check that any tint or additive you add is covered too.
Tell us the clear PP grade you run now
A polymer chemist reviews every request, then matches your grade or finds a qualified equivalent 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