28% VA EVA: grades by melt index, names, tolerances and substitutes

28% VA EVA grades by melt index

Most producers that make high-VA EVA offer a ladder of 28% VA grades that differ mainly in melt index (MI). At the same VA, MI tracks molecular weight: low MI is tough with more melt strength, and high MI flows easily and gives a low melt viscosity. The table lines up the common steps we found on public producer data sheets. All MI values are at 190°C / 374°F, 2.16 kg. For the end uses, see adhesives and sealants and extrusion coating.

Typical values from public data sheets of several producers. Actual VA on "28%" grades runs from about 26.7% to 28%. Confirm the exact grade on its data sheet and lot COA.

How producers name 28% VA grades

Buyers often search for a grade name like "EVA 28-400". That format is a naming habit, not a standard. Some producers put the VA first and the MI second. One puts the MI first. Others use codes that tell you neither. Read the name as a clue, then check both numbers on the sheet. Trade names below are examples only and belong to their owners. We use them to explain naming, not to offer a brand.

Examples from producers' public grade lists and naming guides. Families, names and availability change; confirm the current data sheet.

How VA and MI are measured on high-flow grades

• VA content. Measured by FTIR (ASTM D5594) or a producer's own method, in weight percent. Two producers' "28%" grades can differ by a point or more, so compare the stated values, not the name.
• MI on low and mid grades. ASTM D1238 at 190°C / 374°F, 2.16 kg, reported in g/10 min. This is the number to compare for grades up to a few hundred.
• MI on very high-flow grades. At several hundred g/10 min and above, the standard test runs very fast. Producers handle this in different ways. One older producer guide reports its MI values as "ASTM D1238, modified". Another marks some of its 150 and 400 values as estimates from tests at other conditions. Some state only melt viscosity.
• Melt viscosity. Some sheets add Brookfield viscosity at 190°C / 374°F by ASTM D3236. One producer lists about 20,600 mPa·s for a 28% VA, 400 MI grade and about 9,000 mPa·s for a 30% VA, 870 MI grade. When two high-flow grades are compared, this number is often more useful than MI.
• Other COA values. Density, DSC melting point (about 62–76°C / 144–169°F for 28% VA class grades, lower at higher MI), and sometimes ring and ball softening point. Ask which values the producer reports on each lot.

VA and MI tolerance: what to expect and what to write

Data sheets show typical values. The producer's sales specification sets the range a lot can fall in, and that range is often not public. Ask for it, and write the range your process actually tolerates on the RFQ. Then compare the two before you approve a grade.

• VA. Write a nominal and a range, for example "28 wt% VA, accept 27–29, ASTM D5594 or producer method". Adhesive formulators with tight cloud point or adhesion targets may need a narrower range.
• MI. Write a nominal, a range and the condition, for example "MI 800 g/10 min at 190°C / 374°F, 2.16 kg, ASTM D1238". High-flow grades often have wider MI ranges than film grades, so ask how the producer measures it.
• Melt viscosity, if you rely on it. For high-flow grades in hot melts, add Brookfield viscosity of the neat resin at your temperature, ASTM D3236, if the producer reports it.
• Additives. Antioxidant type and level, and any pellet anti-block or dusting agent. Film and coating grades may also carry slip and antiblock.
• COA. VA and MI on every lot, with the test method. Every prime lot from our suppliers ships with a COA.
• Documents. FDA or Health Canada letter for the exact grade if needed, SDS, and REACH or Prop 65 statements if your customers ask. See resin compliance documents.

How close a substitute must be: 800 vs 850 MI and other swaps

A common case: the formula calls for a 28% VA grade at 800 g/10 min (190°C / 374°F, 2.16 kg), and the closest offer is 28% VA at about 850. On the resin alone, that is about a 6% step in MI, so the neat resin is a little thinner. In a hot melt that is roughly one-third polymer, the change in the finished adhesive is smaller again, and it may fall inside normal lot-to-lot variation of either grade. Close is not the same as proven, though. Judge it on your line.

• Melt viscosity at application temperature. Make the adhesive with the candidate grade and measure Brookfield viscosity (ASTM D3236) at your pot temperature, side by side with the current grade.
• Open time and set time. Run both formulas on the same substrate and bead size. Small viscosity changes move bead shape and cooling rate.
• Bond and heat resistance. Fiber tear on board, peel on fabric, and a heat or cold test matched to the end use.
• VA as well as MI. A 27.6% VA grade and a 28% VA grade at the same MI can differ in cloud point with wax and in adhesion. Compare both numbers.
• Pot stability. Color, char and skinning after hours at temperature. These depend on the antioxidant package as well as the polymer.
• Blending. One producer's guide notes that high- and low-MI grades in the same VA series can be blended to reach an intermediate viscosity. Formulators sometimes use this to hit an old target exactly.
• Low-MI swaps. For film, coating and foam, check melt strength and line behavior, not just MI. Grades at 3 and 6 g/10 min (190°C / 374°F, 2.16 kg) do not neck in, draw down or foam the same way. See finding an equivalent grade, EVA film grades and EVA foam resin.

Packaging, anti-block dusting and storage

• Packaging. 28% VA grades most often ship in 55 lb (25 kg) bags, about 40–55 bags per pallet, or in lined gaylords of about 1,000–1,600 lb. Bulk truck and railcar are mainly for low-MI grades at large users. High-MI pellets are soft and can pack under their own weight.
• Pellet handling additives. High-VA, high-MI pellets block easily. Many grades carry an amide or a mineral dusting to keep pellets free-flowing. One family marks these grades with a W suffix. Others describe a "pellet handling additive" on the sheet.
• When dusting matters. It can haze clear films and coatings, affect adhesion in some formulas, or show up as residue in feed systems. Say on the RFQ if you need an undusted grade.
• Storage. Keep bags cool, dry and out of direct sun, avoid tall stacks in a hot warehouse, and use first in, first out. Blocked pellets can often be broken up, but they slow feeding. See resin shelf life.
• Moisture. EVA picks up little water and is often run as received. Warm high-VA pellets only gently if they are damp, because they soften and stick.

Food-contact letters and other documents

FDA covers EVA copolymers for food contact under 21 CFR 177.1350. That section sets no VA ceiling for plain EVA copolymers. It limits net chloroform-soluble extractives to 0.5 mg per square inch, tested with the food types and conditions of use in 21 CFR 176.170(c), and caps VA at 11% only for maleic anhydride-grafted EVA. Compliance depends on the exact grade and its additives, so ask for the producer's letter for that grade. For adhesives in food packaging, 21 CFR 175.105 applies, the 177.1350 extractives limit does not apply to EVA used in a complying adhesive, and the finished adhesive is the formulator's responsibility. See hot melt EVA for that case.

Personal care and cosmetic converters often ask for the same FDA letters as a baseline even when the package does not hold food. In Canada, ask whether the grade has a Health Canada letter of no objection. See FDA food-contact resin.

What moves 28% VA EVA prices

We do not post prices. These are the forces that move a quote for 28% VA EVA. For EVA as a whole, see EVA price per pound.

• Feedstocks. Ethylene and vinyl acetate monomer. VAM is made from ethylene and acetic acid, so swings in acetic acid and natural gas feed through.
• Fewer lines for high VA. 28% VA and high-MI grades come from fewer reactors than low-VA film EVA. One outage or turnaround can tighten supply of a whole MI step.
• Competing demand. Solar encapsulant film draws on the same high-VA capacity, and footwear foam competes for reactor time, mostly in Asia. Both pull on import availability.
• Imports, freight and duties. Imported 28% VA grades are often offered against domestic supply. Ocean freight, port timing and duties change the landed cost.
• Grade and package. Very high-MI grades, special additive packages and undusted grades can cost more. Bags cost more per pound to handle than bulk.
• Order size and timing. Price per pound steps down from one gaylord to pallets of bags to truckload. A spot buy during a tight month costs more than scheduled releases. See how resin is priced.

Comparing 28% VA EVA quotes: a checklist

• Same VA and MI basis. Nominal VA and MI from the data sheet, with the test method and condition, not just a name like 28-800.
• Sales specification. The VA and MI range a lot can fall in, and what happens if a lot falls outside it.
• Prime or not. Prime, wide-spec or off-grade, stated in writing. See wide-spec and off-grade for how the tiers work.
• Additives and dusting. Antioxidant, pellet anti-block or dusting, and slip or antiblock for film grades.
• Documents. COA with every lot, FDA letter for the exact grade, SDS.
• Package and weight. Bags, gaylords or bulk; net weight per package and per pallet; pallet count per truck.
• Freight terms. Delivered or FOB, ship-from location and transit time.
• Lead time and lot. Ship date, and whether the whole order is one lot.
• Sample. Whether a sample from the same lot is available to qualify before the full order.

Common questions

If your grade is not listed, tell us what you run. We source commodity, engineering and specialty resins.