EVATANE 28-03 EVA Copolymer Resin,Soft & Flexible Grade

In hot-melt adhesive compounding for packaging, edgebanding, and bookbinding, EVATANE 28-03 functions as the high-vinyl-acetate base polymer because the 28 wt% vinyl acetate disrupts polyethylene crystallinity, reducing ambient-temperature modulus and improving compatibility with rosin ester and hydrocarbon tackifiers. The grade carries a nominal melt flow rate of 3 g/10 min when tested to ISO 1133-1:2022 at 190 °C under 2.16 kg load, which positions it for formulations requiring controlled open time rather than low-viscosity gun application. Adhesive compounds containing this polymer are typically evaluated under FDA 21 CFR 175.105 for indirect food-contact packaging adhesives and may also be assessed under FDA 21 CFR 177.1350 for ethylene-vinyl acetate copolymers; REACH Regulation (EC) No 1907/2006 and RoHS Directive 2011/65/EU Annex II apply when the finished adhesive enters electrical or electronics packaging streams. Typical addition level for EVATANE 28-03 is 28–38 wt% of the total adhesive formula, with tackifier resin at 35–48 wt%, microcrystalline or Fischer-Tropsch wax at 8–15 wt%, and antioxidant at 0.3–0.8 wt%. Exact ratios are adjusted against Brookfield viscosity measured per ASTM D3236 at 180 °C; published data for this specific formulation is limited. On production-scale batches, the polymer is charged first into a jacketed sigma-blade mixer at 120–130 °C and masticated until the melt no longer shows translucent pellet centers; tackifier resin is added only after the EVA phase clears the blade wall, otherwise resin can block blade clearance and increase motor load. For continuous lines, co-rotating twin-screw extruders with L/D 36:1 to 48:1 are used with screw speed 200–350 rpm, vacuum devolatilization at -0.06 to -0.08 MPa, and water-ring strand cooling at 15–25 °C. Terminal products include carton closure adhesives, bookbinding spine glue, flexible packaging lamination adhesives, and edgebanding tape coatings. Sustained service above 60 °C reduces cohesive strength, and aromatic or ketone solvents swell the compound; solvent-based primer systems require compatibility testing before commercial adhesion trials.

What Restricts Filler Loading in Halogen-Free Cable Jacket Compounds?

The limiting variables are melt pressure, elongation retention, and dispersive mixing capacity of the compounding line. EVATANE 28-03 at 28 wt% vinyl acetate facilitates high loadings of aluminium trihydrate or magnesium hydroxide because the amorphous phase absorbs shear without the crystalline yield points of lower-VA EVA grades. In wire and cable laboratory work, a base compound is typically designed as 100 phr EVATANE 28-03 or a 70:30 to 80:20 EVA/LLDPE blend, with filler addition of 120–200 phr, organosilane coupling agent at 1–2 phr, antioxidant at 0.5–1.5 phr, and processing aid at 0.5–2.0 phr. Halogen-free jacket compounds are tested to IEC 60754-1 and IEC 60754-2 for halogen acid gas content, pH, and conductivity; smoke density is assessed by IEC 61034-2; building cables under CPR Regulation (EU) No 305/2011 also reference EN 50267-2-2 for corrosivity of fire effluent. Automotive cables may be validated to ISO 6722 for abrasion and long-term thermal aging. On a co-rotating twin-screw extruder with L/D 44:1, polymer is fed at the main throat, while filler is introduced through a side feeder after the melt reaches 130–150 °C to avoid wiping the screw root. Screw configuration includes kneading blocks with 30°, 45°, and 90° stagger; melt temperature is held between 145 °C and 170 °C because acetic acid evolution accelerates above 180 °C and reduces insulation resistance after thermal aging. Screen changers with 200–400 μm mesh remove undispersed filler agglomerates, but rising screen pressure during continuous runs signals batch-to-batch variance in magnesium hydroxide particle size distribution and requires feeder recalibration. Terminal products include low-smoke zero-halogen sheathing for building riser wiring, control cable jackets, shipboard electrical insulation, and battery cable jackets in electric vehicle harnesses.

When Blowing Agent Decomposition Kinetics Must Align with Melt Crosslinking

Processing crosslinked EVA foam is controlled by two competing thermal reactions: dicumyl peroxide decomposition for polymer crosslinking and azodicarbonamide decomposition for gas evolution. Dicumyl peroxide exhibits a 10-hour half-life temperature near 117 °C and a 1-hour half-life near 135 °C, while azodicarbonamide begins significant gas release near 140–150 °C depending on particle size and zinc-based activators. If the blowing agent decomposes before the EVA phase develops sufficient melt strength, cells collapse or coalesce into elongated voids; if gas evolution lags behind the crosslinking front, internal pressure exceeds the partially cured melt and causes split sheets. Footwear foam articles are not covered by a single EU harmonised standard; physical testing is commonly carried out to ISO 868 for Shore A hardness and ISO 1798 for tensile properties of flexible cellular materials. REACH Annex XVII and brand restricted-substance lists apply to residual azodicarbonamide and its semicarbazide decomposition product in finished foam articles. Formulation for midsole sheet stock commonly contains 100 phr EVATANE 28-03 or a blend of 70–85 phr EVATANE 28-03 with 15–30 phr lower-VA EVA and polyolefin elastomer, plus 3.0–5.0 phr azodicarbonamide, 0.6–1.0 phr dicumyl peroxide, 1–2 phr zinc oxide, 0.5–1.5 phr zinc stearate, and 5–15 phr calcium carbonate filler. Density and hardness are adjusted by alternating blowing agent level within this range; published data for this specific formulation is limited. Production is typically executed in a Banbury internal mixer with drop temperature 105–115 °C, followed by a two-roll mill set at 80–90 °C to sheet the batch, then compression molding at 155–165 °C for 40–60 s/mm thickness at mold pressure 12–18 MPa. Batch-to-batch variation in blowing agent particle size changes decomposition onset and requires final foam density checks after every campaign. Terminal products include EVA midsoles, sheet stock for die-cut secondary soles, flip-flop soles, soft foam padding, and slip-sheet inserts.

For photovoltaic module encapsulation, EVATANE 28-03 is converted into a crosslinked encapsulant sheet through cast-film extrusion and subsequent vacuum lamination. The 28 wt% vinyl acetate content reduces crystallinity enough to lower crystal haze relative to lower-VA EVA grades; transmittance and yellowness index for encapsulant sheets are evaluated by ISO 13468-1 and ASTM E313, though long-life module qualification data for this specific grade remain limited compared with solar-specific EVA grades. Module encapsulant films are validated under IEC 61215-1:2021 for design qualification, IEC 61730-2:2016 for safety qualification, and UL 1703 for North American listed modules; damp-heat aging at 85 °C/85% RH for 1,000 h is the primary threshold for evaluating adhesion retention, yellowness index, and backsheet delamination. In encapsulant sheet formulation, 100 phr EVA is combined with 0.3–1.0 phr silane coupling agent, 0.6–1.5 phr peroxide, 0.1–0.5 phr UV stabilizer, and 0.1–0.3 phr antioxidant. Sheet extrusion is performed on a single-screw extruder with L/D 30:1 to 36:1, melt temperature 85–100 °C, chill-roll temperature 10–18 °C, and thickness tolerance ± 0.02 mm. The sheet is laminated in a vacuum laminator at 145–160 °C for 8–15 min; gel content is checked by solvent extraction and typically must exceed 75% to avoid creep in service. Terminal applications are glass/backsheet solar modules, glass-glass bifacial modules, and building-integrated photovoltaic laminates.

Carrier Resin Selection Criteria for Polyolefin Masterbatch on Twin-Screw Lines

Selection of EVATANE 28-03 as a masterbatch carrier is governed by the need to wet high-specific-surface-area pigments and functional additives at lower melt pressure while maintaining pellet strand integrity. The EVA phase lowers viscosity enough for pigment encapsulation but retains a melt-flow rate of 3 g/10 min (ISO 1133-1:2022), which reduces dusting and strand breakage compared with low-viscosity wax carriers. Masterbatch pellets for food-contact packaging must comply with Regulation (EU) No 10/2011 migration limits and FDA 21 CFR 177.1350 when the EVA carrier remains in the final polymer article; electrical masterbatches are checked for RoHS Directive 2011/65/EU Annex II restricted substances and REACH Article 33 information duties. Typical carrier addition is 15–40 wt% of the masterbatch, with the remaining 60–85 wt% consisting of pigment, mineral filler, antistat, or flame-retardant additive. Carrier dosage is reduced when using high-oil-absorption organic pigments and increased with dense inorganic pigments to prevent resin-rich striping. Production uses a co-rotating twin-screw extruder with L/D 40:1, EVA fed in the main throat at 120–140 °C, additives side-fed after the melt passes the first kneading block, vacuum devolatilization at -0.08 MPa, and strand cooling at 20–35 °C. Pelletizer throughput is matched to strand diameter 3–5 mm; strand embrittlement caused by high pigment loading or residual moisture is corrected by lowering screw speed and increasing die temperature to 160–170 °C. Terminal masterbatch grades are used for tinting polyethylene films, injection-molded caps, wire and cable sheathing, footwear soles, and adhesive films.

As a modifier in impact-resistant polyolefin compounds, EVATANE 28-03 is incorporated into polypropylene and high-density polyethylene systems at 5–25 wt% to shift ductile-to-brittle transition behavior downward and improve notched impact performance. Below 5 wt%, the effect is masked by crystallinity; above 25 wt%, the EVA phase may reduce flexural modulus and create phase inversion in some polypropylene grades. Resulting compounds are tested to ISO 179-1 or ISO 180 for Charpy/Izod notched impact, ISO 527-2 for tensile properties, and ISO 178 for flexural modulus. When intended for food-contact articles, the EVA constituent is assessed under FDA 21 CFR 177.1350 and the olefin matrix under FDA 21 CFR 177.1520; the final blend must also conform to Regulation (EU) No 10/2011. Compounding is carried out in co-rotating twin-screw extruders at barrel set temperatures 180–200 °C, with EVA pellets either dry-blended with PP/PE granules or side-fed after the polymer melt reaches stable torque. Injection molding of the finished compound uses barrel profile 190–210 °C, mold temperature 30–50 °C, and clamp force selected for projected area; a 1,500 kN toggle clamp machine is common for automotive interior trim tools. High shear rates should be avoided above 220 °C due to EVA thermal degradation. Terminal products include automotive interior trim, appliance housings, industrial crates, and sports equipment requiring low-temperature impact resistance.