HANWHA EVA 1826 (em inglês)

Introduced within the HANWHA EVA copolymer portfolio of Hanwha TotalEnergies Petrochemical Co., Ltd., HANWHA EVA 1826 is an ethylene-vinyl acetate thermoplastic resin with a nominal vinyl acetate comonomer incorporation of 18 wt% and a melt mass-flow rate of 2.6 g/10 min when determined at 190°C under a 2.16 kg dead weight in accordance with ASTM D1238. The grade is manufactured as a pelletized copolymer under CAS number 24937-78-8 and is supplied with a typical density of 0.941 g/cm³ per ASTM D1505. The 18 wt% vinyl acetate content places the material in the intermediate polarity range of the producer’s EVA series: it offers a measurable reduction in crystalline melting point relative to 13 wt% and 15 wt% vinyl acetate grades, while retaining greater melt strength than 28 wt% vinyl acetate grades used in hot-melt compounding. The melt rheology at 190°C corresponds to a relatively low-viscosity thermofusible material suitable for injection molding, extrusion foaming, and compounding; the same comonomer content introduces polar acetate side groups that modify adhesion to polar substrates and increase compatibility with fillers such as calcium carbonate, zinc oxide, and magnesium hydroxide compared with nonpolar LDPE homopolymer. Published producer data for HANWHA EVA 1826 indicate a Shore A hardness of 88, a Vicat softening point of 64°C, and a melting peak near 82°C. These values should be read as typical lot averages, not as substitute specifications; each commercial shipment is governed by the certificate of analysis.

What Melt Rheology and Comonomer Content Define HANWHA EVA 1826?

Lot-to-lot control of the copolymer is anchored to a small set of standardized methods. Melt mass-flow rate testing per ASTM D1238-20 or ISO 1133-1:2022 at 190°C and 2.16 kg yields a nominal 2.6 g/10 min, with producer-typical control limits around ±0.3 g/10 min. Vinyl acetate content is determined by infrared spectroscopy per ASTM D5594; the 18 wt% target alters the sequence distribution along the polyethylene backbone and reduces crystallinity to the range associated with a 82°C melting peak and a 64°C Vicat softening point. Density at 23°C is 0.941 g/cm³ per ASTM D1505, which is useful for gravimetric feed calibration on loss-in-weight dosing units. The Shore A hardness of 88 per ASTM D2240 positions the material in the soft-flexible range, and the tensile property envelope is commonly reported around 21 MPa stress at break and 800% elongation at break per ASTM D638. The table below consolidates the principal published values.

On single-screw extruders with L/D ratios between 24:1 and 30:1, HANWHA EVA 1826 is normally processed with a barrel temperature profile beginning at 150°C in the feed zone, rising to 180°C in the compression zone, and holding at 190°C to 200°C at the metering zone and die. Screw designs with a compression ratio of 2.5:1 to 3.5:1 and a Maddock or pineapple mixing section are recommended for homogenizing fillers and blowing agents; excessive screw speeds above 120 rpm can generate shear heating above 210°C and initiate acetic acid release from the vinyl acetate comonomer. The liberated acetic acid is detectable as a sharp odor and can corrode downstream metal surfaces and cause bubble collapse in foam. In injection molding, cylinder temperatures from 170°C to 200°C and mold temperatures from 20°C to 40°C are typical; clamp force requirements follow the flow length and wall thickness but are generally lower than those for semicrystalline polypropylene at the same MFR because of the copolymer’s lower melt viscosity. Injection molders have observed that a holding pressure of 50–80 MPa and a back pressure of 0.5–1.0 MPa are adequate for many small-to-medium parts; high cushion settings above 4 mm can increase residence time and promote thermal degradation. Pre-drying is not required when pellets are stored in sealed silos below 60% relative humidity; if surface moisture exceeds 0.05 wt%, a 60–70°C desiccant or hot-air drying step for 2–4 hours prevents steam-related surface defects and dimensional instability. Production-scale foam lines have reported that melt pressure variation exceeding ±5 bar at a fixed screw speed can indicate non-uniform blowing-agent dispersion; when such variation appears, the recommendation is to reduce masterbatch feed rate or increase barrel residence time before adjusting the base temperature profile.

When EVA 1826 Is Selected for Foam Expansion and Shoe Sole Molding

Foam expansion with chemical blowing agents is among the primary commercial uses of HANWHA EVA 1826. The compound is typically prepared in an internal mixer or open mill at 100–110°C, with azodicarbonamide at 2.0–4.0 phr, dicumyl peroxide at 0.6–1.2 phr as crosslinking initiator, zinc oxide at 0.5–1.5 phr as activator, and stearic acid at 0.5–1.0 phr as processing aid. The mixing cycle is controlled to discharge before the half-life temperature of dicumyl peroxide is reached; otherwise, premature crosslinking creates hard gels that appear as surface bumps in the calendered sheet. The compound is then calendered to sheet, pre-formed into pre-foamed blanks, and expanded in a two-stage press system at 150–170°C. The 18 wt% vinyl acetate content provides sufficient polarity for filler wetting and enough amorphous character to permit expansion ratios between 1.3 and 1.8 while retaining ultimate elongation. HANWHA EVA 1826 is distinguishable from lower-VA grades in shoe sole foaming because lower-VA grades require higher activator loadings to achieve equivalent filler dispersion, while higher-VA grades can generate excessive tack and longer demolding times. In footwear midsoles, the grade is used in formulations targeting 0.20–0.30 g/cm³ finished foam density, with compression set at 50% deflection typically below 35% after 24 hours at room temperature. Published data for this specific configuration is limited; therefore, producers are advised to validate compression-set behavior against ASTM D395 Method B on production-slab samples before locking formulation. The same copolymer can be injection-molded directly as unfoamed flex items, where its Shore A 88 hardness and 800% elongation provide flexural fatigue resistance. For wire and cable sheathing, EVA 1826 may be compounded with aluminum trihydrate and magnesium hydroxide for low-smoke halogen-free formulations, although the producer does not list a specific limiting oxygen index for the base resin.

Extrusion coating and adhesive lamination represent a secondary application window. The 18 wt% vinyl acetate content lowers the sealing initiation temperature relative to pure polyethylene and provides adhesion to aluminum foil and polyester film; however, producers report that web speed is limited by draw resonance at melt temperatures above 200°C. The melt mass-flow rate of 2.6 g/10 min is high enough for thin-coat weight control down to 15 g/m² with chill-roll temperatures near 15°C, but lower than coating-specific EVA grades with MFR above 5 g/10 min. In adhesive compounding, EVA 1826 is dissolved or melt-mixed with tackifier resins and waxes; its vinyl acetate side groups influence solubility parameter matching with rosin ester tackifiers and increase open time compared with LDPE. Published data for specific coating configurations is limited.

Relative to other HANWHA EVA grades, EVA 1826 occupies the intermediate position between high-melt-strength extrusion grades and high-flow injection grades. HANWHA EVA 1810, with a nominal 18 wt% vinyl acetate content and 1.0 g/10 min MFR, delivers greater melt tension and bubble stability in blown-film and heavy-gauge sheet, but requires higher motor amperage and slower screw recovery. HANWHA EVA 1530, with 15 wt% vinyl acetate and a nominal 3.0 g/10 min MFR, flows more readily into thin-wall cavities but sacrifices polar adhesion and low-temperature flexibility. HANWHA EVA 1315, at 13 wt% vinyl acetate and 1.5 g/10 min MFR, is stiffer and less tacky, making it preferable for rigid packaging applications where pliability is secondary. The table below summarizes these distinctions.

Regulatory Status and Food-Contact Limitations

From a compliance standpoint, ethylene-vinyl acetate copolymers are covered under FDA 21 CFR 177.1350 for indirect and direct food-contact uses when the finished article complies with the specified extractables and end-use limitations. The European framework for plastic materials and articles intended to come into contact with food is Regulation (EU) No 10/2011; EVA copolymers are generally subject to overall migration limits of 10 mg/dm² and, where applicable, specific migration limits for vinyl acetate monomer. HANWHA EVA 1826 is supplied under a generic EU declaration confirming that it does not intentionally contain substances of very high concern above 0.1 wt% as defined by REACH, and that it falls outside the scope of RoHS Directive 2011/65/EU when used in electrical and electronic equipment because it is not an electrical component. The grade is not supplied with USP Class VI or ISO 10993 biological certification; therefore, it is not qualified for long-term implantable medical-device contact. For food-contact use, the converter must verify that the final formulation, including blowing agents, antioxidants, and colorants, meets the migration limits under the intended time-temperature conditions. The copolymer decomposes by acetic acid elimination above 220°C; therefore, it is not recommended for processing at melt temperatures above 230°C or for continuous service above 80°C under load. Avoid combination with amine-based additives due to premature ester aminolysis and acid-base reactions that reduce molecular weight stability.

Storage stability is best maintained in closed, moisture-resistant packaging at ambient temperature. Prolonged storage above 40°C can increase pellet blocking, particularly in warm climates; floor storage of opened bags should be rotated within 12 months. If outdoor storage cannot be avoided, the pellets should be kept under opaque covers and away from direct sunlight to minimize surface oxidation and yellowing. Silos handling HANWHA EVA 1826 should be purged with dry air and equipped with aeration to prevent moisture condensation; conveying line velocities above 25 m/s may generate fines and angel hair, which affect downstream gravimetric feeding accuracy. No specific shelf-life limit is stated by the supplier, but end users are advised to verify pellet color and MFR after any storage period exceeding 12 months.