The short answer
EVA is specified by two numbers: vinyl acetate (VA) content and melt index at 190°C / 374°F, 2.16 kg. As a rough guide, about 2–9% VA covers most film, about 9–20% covers heat-seal and cling layers, and foam grades start near 4%; about 18–22% is the most common window for crosslinked footwear foam, with some shoe foam grades up to about 28%; and about 28% is the most common hot-melt adhesive base. Higher VA is softer, clearer, more adhesive and lower melting. Match both numbers to the grade you run now.
This page lines EVA up by VA content. For processing, grade families and when to use something else, see the EVA page.
Typical spec window
| Property | Typical range | Test method |
|---|---|---|
| Vinyl acetate content | About 2–40% across most commercial grades; tolerance set per grade | FTIR, ASTM D5594; ISO 8985 |
| Melt index | From under 1 to several hundred g/10 min, by end use | ASTM D1238 or ISO 1133, 190°C / 374°F, 2.16 kg |
| Density | Rises with VA; about 0.93–0.95 g/cm³ for most grades | ASTM D1505 or D792; ISO 1183 |
| Melting point | Falls as VA rises | DSC, ASTM D3418 or ISO 11357-3 |
| Hardness | Falls as VA rises | Shore durometer, ASTM D2240 or ISO 868 |
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
| VA content | Typical uses | Melt index notes |
|---|---|---|
| About 2–9% | Blown and cast film, sealant layers, stretch and cling film | Film grades, in the same low range as LDPE film |
| About 9–20% | Softer, tougher film, heat-seal, stretch and cling layers, flexible molding, some foam | Low to moderate MI |
| About 18–22% | Crosslinked foam for footwear midsoles and padding; tubing and soft parts | Foam formulas are tuned to the exact MI |
| About 25–33% | Hot-melt adhesives (often 28%), encapsulant film, wire and cable compounds | Hot-melt grades from tens to several hundred g/10 min |
Bands overlap and are typical, not limits. Foam grades run from about 4% VA up, and some shoe foam grades are about 28%.
How to tell grades apart
- VA content. A point or two of VA changes softness, clarity, adhesion and seal temperature. Order the VA you run, with a tolerance.
- Melt index. At the same VA, lower MI is tougher with more melt strength; higher MI flows and wets better. In hot melts, MI drives viscosity, open time and set speed.
- Additives. Film grades carry slip, antiblock and antioxidant; many adhesive and compounding grades carry none.
- Pellet handling. High-VA grades are often dusted to stop pellets sticking together.
- Heat stability. Higher-VA grades break down at lower temperatures and release acetic acid. Most EVA runs at about 160–220°C / 320–428°F, with the ceiling set on each grade sheet.
What to put on your RFQ or PO
- VA content. In percent, with the tolerance you accept.
- Melt index with the condition. At 190°C / 374°F and 2.16 kg (ASTM D1238), nominal value and spec range.
- Additives. Slip, antiblock and antioxidant for film; none for some adhesive and compounding uses. Antistat or UV only if the end use needs it.
- Dusting. Say if a pellet dusting agent would contaminate your process.
- Color. Natural, or the concentrate you add and its carrier.
- Food contact. The producer’s FDA letter for the exact grade. EVA letters often cite 21 CFR 177.1350, which sets no VA ceiling for plain EVA and limits extractives, so compliance depends on the exact grade and its additives.
- COA values to check. VA content and melt index on every lot, and gel count for film if the grade lists it.
- Packaging. 25 kg (55 lb) bags or gaylords. High-VA pellets can block in a hot warehouse, so plan cool storage and first-in, first-out use.
- Quantity and release size. Total quantity, how much 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 VA and MI from another producer. The closest swap. For foam and hot melt, run a trial: small differences shift foam density, open time and set speed.
- A nearby VA at the same MI. Changes softness and seal temperature. Test before you switch.
- Metallocene PE or plastomers. Low seal temperature and toughness without VA odor. See metallocene PE and PP.
- Ethylene acrylate copolymers. Similar softness, generally with better heat stability in processing.
- LDPE or LLDPE. For low-VA film where only general toughness matters. See LDPE blown film resin.
- TPE or TPV. For molded soft parts that need better heat and compression set. See TPE and TPV.
Common processing problems
- Gels, specks and vinegar smell: gels in film and black specks
- Film that sticks to itself: film blocking
- Weak seals: heat seal failures
- Soft parts that hang up: parts sticking in the mold
- Yellowing from heat: heat discoloration
Common questions
What does VA content mean in EVA?
VA content is the percentage of vinyl acetate in the copolymer. As it rises, EVA becomes softer, clearer, more flexible and more adhesive, and its melting point drops. Low-VA grades behave like tough polyethylene; high-VA grades behave more like rubber.
What VA content is used for EVA foam?
Crosslinked footwear and padding foam most often uses EVA of about 18–22% VA, with some shoe foam grades up to about 28%. Packaging foam can start near 4–6% VA. The crosslinker, blowing agent and filler are tuned to the base grade, so match VA and melt index when you change suppliers.
What EVA is used for hot-melt adhesives?
Most hot melts use high-VA EVA, often about 28%, in melt indexes from tens to several hundred g/10 min. Higher MI lowers melt viscosity, and VA content changes adhesion and flexibility. Small changes in either shift open time and set speed.
Why does EVA smell like vinegar at the press?
That is acetic acid from vinyl acetate breaking down under too much heat or residence time. It corrodes steel and causes gels and specks. Lower the melt temperature, shorten residence and purge with LDPE before shutdown. Higher-VA grades break down at lower temperatures.
Tell us the EVA 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