HANWHA EVA 1159 (em inglês)

Introduced under the designation HANWHA EVA 1159, this ethylene-vinyl acetate copolymer is produced by continuous high-pressure radical copolymerization of ethylene and vinyl acetate. The grade identifier encodes a nominal vinyl acetate content of 11 wt% and a melt mass-flow rate of 5.9 g/10 min when determined at 190 °C under a 2.16 kg load in accordance with ASTM D1238-13 or ISO 1133-1:2022. Solid-state density at 23 °C is approximately 0.930 g/cm³ under ASTM D1505-18 or ISO 1183-1:2019. At 11 wt% vinyl acetate, the copolymer retains a comparatively well-developed ethylene crystallite population relative to flexible film grades, which controls the balance of stiffness, melting range, and solvent resistance. The molecular composition is statistical rather than block-like because high-pressure free-radical kinetics produce short vinyl acetate sequences distributed along the polyethylene backbone. The material is supplied as stabilized pellets and is intended for melt compounding, injection molding, and selected foam or polyolefin modification applications.

Storage follows polyolefin practice. The resin is not inherently hygroscopic, but condensation on cold pellet surfaces can introduce moisture-related splay in molded parts. When pellets are moved from cold storage into a warmer processing hall, a desiccant hopper dryer set at 60 °C for 2 h is acceptable for surface moisture removal; dryer temperatures above 80 °C can approach the softening range and cause pellet agglomeration. Cooled closed-loop pneumatic conveying with dew point below -20 °C is commonly used to limit condensation during long transfer lines.

What Melt-Temperature Limits Govern 1159 During High-Shear Conversion?

The melt mass-flow rate of 5.9 g/10 min places the grade in the medium-high fluidity region of the EVA portfolio. On reciprocating-screw injection molding machines with screw L/D ratios of 20:1 to 24:1 and compression ratios of 2.5:1 to 3.0:1, a barrel profile of 160 °C to 210 °C from feed to nozzle is adequate for most short- to medium-flow-length molds. Mold temperatures between 20 °C and 40 °C are used for thin-wall parts; thicker sections may require lower melt temperature to reduce sink and frozen-in stress. The nozzle melt temperature should not remain above 230 °C for extended residence times, because deacetylation of the vinyl acetate comonomer can release acetic acid, reduce molecular weight, and generate surface defects. Screw and barrel metallurgy in hot sections should be selected for weak organic acid exposure; purging with a low-MI polyethylene before shutdown reduces carbonaceous residue formation on the screw and non-return valve.

In pigment and additive masterbatch production, the 11 wt% vinyl acetate level provides a modest polar shift that aids wetting of organic pigments and carbon black without approaching the soft, blocking-prone character of EVA grades containing 28 wt% VA or higher. Compounding on a co-rotating twin-screw extruder with 40:1 L/D and side feeding is one established route; melt temperatures are typically controlled between 190 °C and 220 °C. Because the grade is temperature-sensitive, screw design should limit specific energy input in high-intensity kneading blocks, and melt pressure before the screen changer should be monitored to detect early deacetylation or pigment wetting failure. Published data for this specific 1159 masterbatch configuration is limited; dispersion quality must be validated by filter pressure rise and optical film draw-down tests on the target line.

Specification Profile and Comparative Position Across Vinyl Acetate Grades

Representative values in the table are drawn from the manufacturer’s published datasheet format and must be verified against the lot-specific certificate before release of finished articles. Short-term tensile behavior of the base resin under ASTM D638-14 with Type IV specimens at 50 mm/min is typically in the range of 10–14 MPa for this vinyl acetate level; lot-to-lot variation and test speed materially affect the recorded value, so end-use design should use measured data rather than nominal values.

The 1159 designation differs from lower-melt-index film grades in the same Hanwha EVA portfolio primarily in its flow-to-acetate ratio. Film and profile grades may carry nominal melt indices near 1.5–2.0 g/10 min and vinyl acetate contents of 13–18 wt%, which favor bubble stability and melt strength over injection fill speed. Photovoltaic encapsulant grades occupy a different segment with vinyl acetate contents near 28–33 wt% and higher optical clarity, crosslinking response, and interfacial adhesion to glass; they are not direct substitutes for 1159 in rigid polyolefin modification or injection molding because of their lower stiffness and higher surface tack. Within the same vinyl acetate band, 1159 is more fluid than low-MI extrusion grades, which shifts selection toward masterbatch carrier, injection molded flexible articles, and foam applications.

In crosslinked foam, the 11 wt% vinyl acetate content lowers the melting peak relative to homopolymer LDPE, allowing Banbury or roll-mill fluxing at lower stock temperatures. A typical formulation direction uses chemical blowing agent loadings of 3–6 wt% azodicarbonamide and peroxide crosslinking at levels determined by the required gel fraction. The 5.9 g/10 min melt flow assists gas dispersion and cell uniformity at nominal expansion ratios, but the exothermic decomposition of the blowing agent requires close temperature control because the copolymer enters accelerated degradation above 230 °C. Published data for torque evolution and gas pressure profiles in this specific grade are limited; processor-scale validation using torque rheometry and differential scanning calorimetry is recommended.

Where end-use certification is required, EVA copolymers of this type may be assessed under 21 CFR 177.1520 for olefin polymers, provided that the final article meets applicable extractive and end-use limitations. REACH and RoHS compliance should be confirmed from the lot-specific product safety certificate and not inferred from the grade designation alone. The resin is incompatible with strong oxidizing agents, aromatic and chlorinated solvents at elevated temperature, and prolonged contact with amine-based additives that can react with acetic acid released during processing; compatibility with such additives should be verified by thermal gravimetric analysis and melt pH measurement.

When an 11 wt% Vinyl Acetate Grade Replaces Higher-VA Copolymers in Polyolefin Modification

Substitution of a 28 wt% VA EVA encapsulant or adhesive grade with 1159 changes the heat-seal response and adhesion profile. Because the vinyl acetate content of 11 wt% is lower, the heat-seal initiation temperature can shift upward relative to higher-VA grades, and peel strength on polar substrates such as PET or glass may decrease. Seal performance should be measured under ASTM F88/F88M-21 across the design sealing temperature, pressure, and dwell-time envelope. In polyolefin modification, addition of 10–20 wt% 1159 to LDPE or LLDPE compounds can raise low-temperature toughness and improve filler acceptance; however, elongation at break and melt strength are influenced by both diluent effects and processing history, so data generated under ASTM D638-14 at fixed speed on conditioned specimens are required for design calculations. Published data for this specific substitution configuration is limited in open literature; direct equivalence to higher-VA copolymers should not be assumed.

Injection molded flexible closures, grips, and mat components use the grade at melt temperatures of 180 °C to 210 °C. Hardness is dependent on vinyl acetate content and filler loading and should be measured under ASTM D2240-15 at 1 s and 5 s readings on conditioned plaques. Mold shrinkage for 11 wt% VA EVA is typically higher than for polypropylene and is influenced by wall thickness, gate geometry, and packing pressure; initial prototype cavities often require 1.5–2.5% linear shrinkage allowance and iteration through mold measurement. The practical upper continuous service temperature is below the Vicat softening point unless the part is crosslinked; sustained load-bearing service above 70 °C can permit creep and dimensional change under stress.