Copolímero de acetato de vinilo de etileno EVAtech EVA 160I/30C

EVAtech EVA 160I/30C Ethylene Vinyl Acetate Copolymer is a high-melt-flow thermoplastic copolymer produced by polymerization of ethylene with vinyl acetate comonomer. The grade designation is interpreted through conventional EVA nomenclature as a nominal vinyl acetate content of 16 wt% and a nominal melt flow index of 30 g/10 min determined under ISO 1133-1:2022 at 190 °C with 2.16 kg load. The suffix 30C is manufacturer-specific and typically signals a coating or clarity-modulated grade, though the suffix is not a standardized designation. Published lot-specific data for this exact configuration is limited; the values provided below are class-typical ranges for EVA copolymers with equivalent comonomer content and melt rheology and should be verified against the certificate of analysis for the production lot in use.

For specification review, class-typical values are tabulated as follows:

In cast film and extrusion coating, the high melt-flow index of EVAtech EVA 160I/30C permits reduced melt pressure and improved wet-out on paper, foil, and oriented polyolefin substrates at lower melt temperatures than EVA grades with melt flow indices below 10 g/10 min. The material is typically processed on single-screw extruders with 24:1 to 30:1 L/D ratios and barrier screws. Melt temperature is normally maintained between 190 °C and 230 °C; exceeding 240 °C accelerates acetic acid elimination from the vinyl acetate groups and increases die-lip deposit formation. Operators should purge with low-melt-index LDPE before shutdown to reduce stagnant resin and gel accumulation.

Which Processing Windows Apply to High-Melt-Flow EVA 160I/30C?

On a 60 mm 28:1 single-screw extruder with a barrier screw, the melt pressure at 150 kg/h throughput is typically lower than that of a 6 g/10 min EVA at the same screw speed, because the higher melt-flow index reduces shear viscosity. Extruder zone settings commonly begin at 120–150 °C in the feed section, rise to 170–200 °C in the compression and metering zones, and hold at 200–220 °C in the adapter and die. Melt temperature measured at the die exit should remain below 230 °C for extended runs. If melt temperature exceeds 240 °C, gel frequency in the coating web increases and acid-neutralizing additives in the formulation may be consumed more rapidly.

The resin is not recommended as the sole blown film resin because bubble stability becomes marginal at blow-up ratios above 2.0. In blown film, EVAtech EVA 160I/30C is generally blended with a lower-MI EVA or LDPE at 20–40 wt% to restore melt strength. Published data for this specific blown film configuration is limited; trials on the target line are required to establish the maximum bubble diameter and frost-line height.

For desiccant drying, the copolymer does not require routine predrying unless surface condensation or prolonged storage in relative humidity above 70% is present. If visible moisture is present, continuous desiccant drying at 70 °C for 2–4 h reduces hydrolytic degradation during extrusion. Avoid combining the resin with amine-based processing aids at high melt temperature, because trace amines can promote deacetylation and acid formation.

Comparative Adhesion, Softening, and Melt-Strength Differences

The product differs from other EVA grades principally in its intermediate vinyl acetate content and high melt-flow index. A 16 wt% vinyl acetate copolymer has higher crystallinity, higher Vicat softening temperature, and lower polar adhesion than a 28 wt% vinyl acetate copolymer. The high melt-flow index reduces melt strength relative to a 2.5 g/10 min EVA with similar vinyl acetate content, which limits blown film use but improves extrusion coating throughput and substrate penetration.

Higher vinyl acetate content in the 28 wt% grade increases polarity, tack, and compatibility with rosin ester and hydrocarbon tackifiers. The 16 wt% vinyl acetate content of EVAtech EVA 160I/30C produces lower surface tack and lower elongation at break but higher thermal resistance. In adhesive formulations, this limits the resin to applications where moderate adhesion and higher softening temperature are preferred. In cast extrusion coating, the high melt-flow index allows wetting of aluminum foil at lower processing temperatures than a 2.5 g/10 min grade, while the moderate vinyl acetate content retains sufficient adhesion to polyolefin substrates.

In polyethylene compound modification, incorporation of EVAtech EVA 160I/30C at 5–20 wt% is used to improve environmental stress crack resistance. Testing under ASTM D1693-15 shows improvement over unmodified high-density polyethylene in many compound systems, although the magnitude of improvement depends on comonomer content, molecular weight distribution of the base polyethylene, and mixing intensity. On a 35 mm co-rotating twin-screw extruder with 40:1 L/D and distributive screw elements, the EVA component disperses readily at melt temperatures below 220 °C.

When EVA 160I/30C Replaces Higher-VA EVA in Coextruded Sealant Webs

Substitution of EVAtech EVA 160I/30C for a higher-vinyl-acetate EVA in a coextruded sealant layer lowers seal tack and may increase the minimum seal temperature unless the sealant layer is blended with a low-density metallocene polyethylene or a plastomer. The reduction in seal initiation temperature relative to pure mLLDPE depends on blend ratio and seal dwell time; heat seal strength should be tested under ASTM F88/F88M-23 and hot tack under ASTM F1921/F1921M-20. Published data for this specific blend configuration is limited, and line-specific trials are required to establish the seal curve.

When replacing a 28 wt% vinyl acetate EVA in a sealant web, operators should expect lower green peel strength and reduced contact clarity. The 16 wt% vinyl acetate resin provides higher Vicat softening temperature and better dimensional stability in warm climates, but the sealant layer may require 5–10 °C higher seal bar setpoint to achieve equivalent peel force. The final seal strength should be determined after conditioned aging at 23 °C and 50% relative humidity for 24 h under ISO 291:2008.

In hot-melt adhesive compounding, EVAtech EVA 160I/30C is not a direct substitute for 28 wt% vinyl acetate EVA in high-tack formulations. The lower vinyl acetate content reduces compatibility with polar tackifiers and may produce phase separation when tackifier loading exceeds 40 wt%. Formulators have used this grade in low-tack, higher-softening-point formulations where melt viscosity reduction is more important than adhesion to polar surfaces. Rheology should be measured using ASTM D3236-15 with a Brookfield viscometer at 180 °C or 190 °C after 4 h of thermal aging to confirm viscosity stability.

For regulatory classification, the unfilled ethylene-vinyl acetate copolymer is generally covered under food-contact regulation 21 CFR 177.1350 for ethylene-vinyl acetate copolymers, provided the vinyl acetate content and extractive limits meet the paragraph specifications for the intended food-contact scenario. Compliance with EU 10/2011 requires migration testing on the final polymer matrix, including any slip, antiblock, or processing aids added downstream. The base unfilled resin is outside the restriction scope of 2011/65/EU RoHS recast for lead, mercury, cadmium, hexavalent chromium, PBB, and PBDE unless intentionally added in pigments or functional additives. Grade-specific REACH SVHC compliance must be certified through the supplier’s SDS and extended SDS when applicable.