HANWHA EVA 2815

HANWHA EVA 2815 is an ethylene-vinyl acetate copolymer supplied as uniform pellets for hot melt adhesive compounding, injection molding of flexible technical components, and crosslinked foam production. The nominal vinyl acetate comonomer content is 28 wt%, and the melt flow rate is 15 g/10 min when measured at 190°C under a 2.16 kg load in accordance with ASTM D1238. The published density is 0.95 g/cm³ per ASTM D1505, and the peak melting endotherm by differential scanning calorimetry is reported near 73°C. These values place the grade between rigid low-vinyl-acetate extrusion resins and soft high-vinyl-acetate elastomers: the 28 wt% acetate content suppresses crystallinity enough to reduce hardness and promote polar adhesion, while the 15 g/10 min melt flow rate avoids the excess softness and pellet blocking that complicate handling of higher-vinyl-acetate copolymers.

Why Is the 28 wt% Vinyl Acetate Level a Process Control Marker?

At 28 wt% vinyl acetate, the acetate side groups interrupt the crystallizable ethylene sequences and lower the crystalline melting point from the 106–110°C range common for low-vinyl-acetate grades to approximately 73°C. The Vicat softening point is approximately 47°C under ASTM D1525. Crystallinity controls the mechanical boundary: the Shore A hardness of 84 per ASTM D2240 is lower than that of an 18 wt% vinyl acetate injection grade and higher than that of a 33 wt% vinyl acetate grade. Tensile strength at break is approximately 12 MPa per ASTM D638, while elongation at break is typically 800% on compression-molded sheet. These properties reflect the residual crystalline network and the high ductility of the amorphous phase.

Comonomer content is also a thermal stability boundary. Acetate groups are thermally labile, and acetic acid evolution accelerates above 200°C. The 28 wt% vinyl acetate level therefore demands melt temperature control rather than allowing arbitrary overheating; small hot spots in a die or hot runner can generate acetic acid that corrodes unplated steel and forms splay defects. The typical property envelope for HANWHA EVA 2815 is summarized in Table 1.

Table 1: Typical property envelope for HANWHA EVA 2815

Pre-drying at 60°C for 4 h is recommended when pellet surface moisture from exposure above 60% relative humidity is observed, because moisture can increase void formation in extruded profiles and molded parts. In single-screw extrusion with a screw L/D of 24:1 to 30:1, a decreasing barrel temperature profile from 120°C at the feed throat to 170°C at the metering section is used; the die temperature is held below 180°C to limit acetic acid release. Screw compression ratio is commonly 2.5:1 to 3.5:1, with shear heating controlled because the melt temperature can exceed the barrel set point by 10–20°C at high screw speeds. In injection molding, melt temperature of 170°C to 190°C and mold temperature of 20°C to 40°C are representative; the 15 g/10 min melt flow fills thin wall sections readily, but gates must be positioned to avoid jetting. Back pressure of 0.5–1.5 MPa improves shot consistency. The operational upper melt limit is 220°C; above this limit, ester pyrolysis releases acetic acid at rates that are measurable by pH drop in cooling water and can corrode unplated tool steels. Published data for this specific configuration is limited; thermal scans and pressure drop measurements on the target line are required to establish final conditions.

Melt flow rate is a single-point indicator, not a full viscosity curve. For high-vinyl-acetate EVA with 15 g/10 min, apparent melt viscosity at 190°C and 100 s⁻¹ is typically in the 100–300 Pa·s range. Capillary rheometry per ISO 11443 is required to establish shear-thinning behavior for hot runner and die design; cone-and-plate measurements per ISO 3219 provide low-shear data for adhesive sag resistance. The resin’s relatively low melt elasticity reduces extrudate swell and melt fracture in thin profiles, but it also restricts blow molding and deep-draw forming. Stringing in hot melt dispensing is controlled more by formulation than by resin alone.

When Hot Melt Viscosity Is Balanced Against Substrate Wetting

Hot melt adhesive compounding with HANWHA EVA 2815 uses heated sigma-blade or vertical mixers at 150–180°C. The resin is combined with hydrocarbon tackifier, microcrystalline wax, and antioxidant packages; mixing continues until the resin forms a clear melt, after which entrained air is removed under vacuum to reduce viscosity scatter. The 28 wt% vinyl acetate content promotes wetting of paperboard, coated carton stock, PVC edge banding, and aluminum foil. The 15 g/10 min melt flow rate permits viscosity in the 800–3000 mPa·s range at 180°C in compounded formulations, although actual values depend on tackifier softening point and wax type. Apparent viscosity is monitored per ASTM D3236 with a Brookfield thermosel; T-peel adhesion on aluminum/polyethylene laminates is commonly measured per ASTM D1876. Open time and set time are formulation-dependent and should not be inferred from resin data alone.

Industrial application equipment includes hot melt tanks with gear pumps, heated hoses, and slot or roller coaters operating at 160–180°C. At temperatures above 200°C, oxidative char forms on tank walls and can clog 100-mesh pump screens, a failure mode observed on production lines that run long hold times without nitrogen blanketing. Dead-end piping should be avoided because stagnant molten adhesive degrades and periodically releases gels that interrupt coating weight control.

Crosslinked foam production with HANWHA EVA 2815 uses compounding on a two-roll mill at 80–100°C to incorporate 2.0–4.0 phr azodicarbonamide, 0.6–1.2 phr dicumyl peroxide, zinc oxide, and stearic acid. The 28 wt% vinyl acetate level lowers the crystalline melting plateau so that gas evolution from the blowing agent and peroxide crosslinking overlap near 170–185°C; this overlap reduces gas loss and improves cell uniformity. Industrial expansion is carried out in compression molding presses or continuous hot-air ovens. The acetate groups improve wetting of mineral fillers and cell stabilizers compared with low-vinyl-acetate grades, but hygroscopic fillers must be pre-dried to prevent pinholes. Foam density, compression set, and tensile properties are evaluated per ASTM D3574 and ASTM D395-18 Method B; published data for this specific configuration is limited, so production trials should map the exotherm profile against part thickness and mold thermal transfer. The resin is not supplied with the blowing agent or peroxide pre-dispersed.

Comparative Property Envelope Against Other Ethylene-Vinyl Acetate Classes

When HANWHA EVA 2815 is compared with lower- and higher-vinyl-acetate classes, the density, melting point, hardness, elongation, and polar adhesion shift in a predictable direction. Table 2 presents representative class values for material selection; the values are not direct lot-to-lot specifications.

Table 2: Representative property comparison across vinyl acetate classes

Compared with lower-VA grades, HANWHA EVA 2815 shows lower hardness and tensile modulus but higher elongation and improved adhesion to polar substrates. Compared with higher-VA grades above 33 wt%, it retains greater melt strength, lower surface tack, and easier pellet handling. In injection-molded parts, the modulus reduction relative to low-VA grades means that load-bearing designs may require thicker sections or mineral reinforcement. In hot melt adhesives, the 15 g/10 min melt flow permits application at 10–20°C lower melt temperature than a 6 g/10 min grade of equivalent vinyl acetate content, which is advantageous on heat-sensitive substrates.

Regulatory compliance depends on extraction limits and additive selection, not resin type alone

Ethylene-vinyl acetate copolymers are referenced for food-contact use in 21 CFR 177.1350, but compliance is determined by the finished article, not the base resin. In the European Union, plastic food-contact materials fall under Regulation EU 10/2011; the overall migration limit for general food contact is 10 mg/dm² or 60 mg/kg. HANWHA EVA 2815 may be screened under RoHS Directive 2011/65/EU for restricted heavy metals and flame retardant residues, but the base resin does not contain intentionally added cadmium, lead, mercury, or hexavalent chromium. REACH registration obligations apply within the European supply chain. Any additive masterbatch, tackifier, plasticizer, or filler changes the regulatory position and must be assessed separately, because the base resin data cannot cover compounded formulations.

Profile and tubing extrusion lines use HANWHA EVA 2815 where a soft, easily sealed, or flexible surface is required without the permanent tack of high-VA copolymers. A single-screw extruder with barrel temperatures of 120–170°C, die temperature of 170–180°C, and cooling water at 10–25°C is used for thin-walled tubing. Melt pressure at the breaker plate should be monitored; excursions above 20 MPa indicate gel accumulation or screen blockage from degraded particles. The resin’s low melt elasticity reduces die swell and supports controlled outer-diameter sizing, but physical property testing should be performed on finished tubes per ASTM D638 for tensile strength and elongation and per ASTM D2240 for hardness. Continuous service under load above 50°C is not recommended because creep increases near the Vicat softening point.

Storage at temperatures above 40°C softens pellets and increases blocking, particularly in bulk silos and hot warehouses. Pallets should be kept dry and away from direct sunlight. If material is overheated above 220°C, thermal decomposition releases acetic acid, carbon monoxide, and light hydrocarbons; local exhaust ventilation is required on die heads, molds, and oil-heated zones. Overheated resin forms gel particles that clog breaker plates and produce surface defects. HANWHA EVA 2815 is not recommended for direct contact with strong oxidizing acids, chlorinated solvents, or low-molecular-weight ketones because these fluids can swell or extract the vinyl acetate phase. Solvent resistance for the intended chemical environment should be confirmed by immersion testing per ISO 175.