The short answer
Bottle-grade HDPE typically runs about 0.2–1 g/10 min melt index at 190°C / 2.16 kg and about 0.950–0.965 g/cm³ density. Homopolymer grades at the top of the density range make stiff dairy and water jugs. Copolymer grades at slightly lower density give the stress-crack resistance (ESCR) that detergent, bleach and chemical bottles need. Drums, IBCs and tanks use HMW-HDPE, bought by high-load melt index.
This page covers HDPE for bottle and container blow molding. For large blow-molded parts such as drums and IBC bottles, see HMW-HDPE. For the whole family, see polyethylene.
Typical spec window
| Property | Typical range | Test method |
|---|---|---|
| Melt index | About 0.2–1 g/10 min for most bottle grades | ASTM D1238 or ISO 1133, 190°C / 2.16 kg |
| High-load melt index | Reported for low-MI and large-part grades | ASTM D1238, 190°C / 21.6 kg |
| Density | About 0.950–0.965 g/cm³ | ASTM D1505 or D792; ISO 1183 |
| ESCR | Varies widely by grade; compare only at the same condition and reagent strength | ASTM D1693 (bent strip) |
| Melting point | About 130–135°C / 266–275°F | DSC, ASTM D3418 or ISO 11357-3 |
| Die swell | Grade-specific; changes bottle weight and wall at the same settings | No common standard; compare on your machine |
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
- Dairy, juice and water jugs (homopolymer)
- Household chemical, detergent and bleach bottles (copolymer)
- Motor oil and automotive fluid bottles
- Agricultural chemical and industrial containers
- Personal care bottles
- Drums, IBC bottles and tanks: see HMW-HDPE
How to tell grades apart
- Homopolymer or copolymer. Homopolymer has the highest density and stiffness and the lowest ESCR. It suits dairy and water, which do not stress-crack PE. Copolymer adds a little hexene or butene, lowers density and raises ESCR for detergents, surfactants and oils.
- Melt index. Lower MI gives more melt strength to hold a heavier parison without sag, and generally more ESCR. Higher MI flows into detail more easily.
- Density. Each step up adds stiffness and top load, which helps lightweighting, but lowers ESCR. Balance the two for what the bottle holds.
- Structure. Unimodal or bimodal. Bimodal grades often give more ESCR at the same density. Grades also differ in die swell, which shows up as a change in bottle weight.
- Additives. Most bottle grades carry antioxidant only. Some carry antistat to keep shelf dust off. UV only for containers stored outdoors.
What to put on your RFQ or PO
- Melt index with the condition. MI at 190°C / 374°F and 2.16 kg (ASTM D1238), plus HLMI at 21.6 kg for low-MI grades. Compare only values at the same load.
- Density. By ASTM D1505, with a range.
- ESCR. The ASTM D1693 value with its condition and reagent strength.
- Type and structure. Homopolymer or copolymer; unimodal or bimodal.
- Additives. Antioxidant, antistat or UV, as the container needs.
- Color. Natural, or the concentrate you add and its carrier. Approve colors on real bottles.
- Food contact. The producer’s FDA letter for the exact grade; PE letters usually cite 21 CFR 177.1520.
- UN-marked containers. The mark belongs to the tested container design, not the resin. A resin change may mean retesting.
- COA values to check. MI (and HLMI if used) and density on every lot.
- Packaging, quantity and release size. Gaylord, bulk truck or railcar; HDPE pellets run about 33–37 lb/ft³. Give 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.
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- Same type, MI, density and ESCR from another producer. The closest swap. Check die swell and bottle weight on the first runs.
- Copolymer in place of homopolymer. Usually safe for ESCR, at some cost in stiffness and top load.
- Homopolymer in place of copolymer. Risky for anything that holds detergents, surfactants or oils.
- Bimodal grades. More ESCR at the same density, often at a higher price.
- Recycled HDPE blends. Natural HDPE PCR often comes largely from dairy jugs, so check ESCR before using it in chemical bottles. See processing PCR resin.
Common processing problems
- Bottles that crack in use or in testing: environmental stress cracking
- Rough or streaked parisons: melt fracture and die lines
- Weight and wall that drift: extruder surging
- Specks: black specks and contamination
- Tails and flash fed back: using regrind
Common questions
What melt index HDPE is used for blow molding?
Bottle grades typically run about 0.2–1 g/10 min at 190°C / 2.16 kg. Household chemical grades tend toward the low end for ESCR and melt strength. Drums and IBC bottles use HMW-HDPE, bought by high-load melt index.
What is the difference between homopolymer and copolymer HDPE for bottles?
Homopolymer is denser and stiffer, with low stress-crack resistance, and suits dairy and water jugs. Copolymer has a little comonomer, slightly lower density and much better ESCR, so it goes into detergent, bleach and chemical bottles.
What ESCR do I need for a detergent bottle?
There is no single number. Ask for ASTM D1693 values at the same condition and reagent strength, compare them with the grade that already passes, and run your own test on bottles filled with the actual product.
Can I use injection-grade HDPE for blow molding?
Usually not. Injection grades have a much higher melt index and lack the melt strength to hold a parison. Blow molding grades are made for the low-MI window and for stress-crack resistance.
Tell us the blow molding 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