| HS Code | 640559 |
| Va Content | 18% |
| Melt Flow Rate | 3 g/10min |
| Density | 0.94 g/cm³ |
| Tensile Strength | 20 MPa |
| Elongation At Break | 700% |
| Hardness Shore A | 94 |
| Vicat Softening Point | 64 °C |
| Melting Point | 85 °C |
| Brittleness Temperature | -70 °C |
| Crystallinity | Low |
As an accredited SINOPEC EVA 18J3 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | SINOPEC EVA 18J3 supplied in 25 kg polyethylene-lined bags, palletized and wrapped for safe handling and storage. |
| Container Loading (20′ FCL) | SINOPEC EVA 18J3 packed in 25kg bags, loaded in 20ft FCL container, about 20 metric tons per container. |
| Shipping | SINOPEC EVA 18J3 is shipped as polymer resin pellets in moisture-resistant woven or kraft bags, palletized and containerized. Keep dry, away from heat and direct sunlight during transit. This material is non-hazardous, but should be handled with care to prevent bag damage and contamination. |
| Storage | Store SINOPEC EVA 18J3 in a cool, dry, well-ventilated area, away from direct sunlight, heat sources, and open flames. Keep original containers tightly sealed to prevent moisture absorption and contamination. Avoid contact with strong oxidizers. Maintain moderate humidity and stable temperatures. Proper storage preserves resin quality and ensures safe handling. |
| Shelf Life | Shelf life is typically 12 months from delivery when stored in a cool, dry, well-ventilated area away from direct sunlight. |
In crosslinked EVA foam midsoles, SINOPEC EVA 18J3 is added at 30–50 wt% of the total EVA resin phase when the remaining resin phase is a higher-VA EVA grade, typically 26–28 wt% VA, with the objective of raising compound viscosity before the blowing reaction begins. The formulation set for compression-moulded or injection-moulded midsoles commonly includes azodicarbonamide at 2.0–5.0 phr, dicumyl peroxide at 0.6–1.0 phr, zinc oxide at 1.0–2.0 phr, stearic acid at 0.5–1.0 phr, and calcium carbonate at 10–30 phr depending on target density and hardness. Mixing is carried out in an intermeshing Banbury mixer only to 110–120 °C, then discharged to a two-roll mill with a nip set below 2.5 mm to avoid premature dicumyl peroxide breakdown; the pelletized compound is subsequently expanded in a closed mould at 170–185 °C and 8–12 MPa, where the blowing decomposition and peroxide crosslinking overlap within a narrow thermal band. Industry compliance for exported footwear components is anchored to REACH Annex XVII of (EC) No 1907/2006, with finished foam tests reported as apparent density under ISO 845:2006, compression set under ASTM D395-16e1, and indentation hardness under ASTM D2240-15 type A. Terminal finished products include injection-moulded midsoles, footbed inserts, flip-flop unitary soles, and anti-fatigue shock pads. The operational boundary is a hard formulation limit: when EVA 18J3 exceeds 50 wt% of the EVA resin phase, the lower MFI of 3.0 g/10 min combined with 18 wt% VA reduces melt elongation at the expanding cell wall, producing density increases beyond 0.20 g/cm³ and compression set drift under ASTM D395 Method B for some moulded geometries.
Halogen-free sheathing compounds built on ATH/EVA matrices impose a narrow processing window between silane grafting and dehydration of the mineral filler, and EVA 18J3 is introduced at 20–40 phr of the polymer phase to provide char support without excessive melt viscosity. In a typical low-smoke flame-retardant cable compound, the total formulation runs at 50–70 wt% aluminium trihydrate, 10–30 wt% LDPE/LLDPE, and 20–40 wt% EVA 18J3, with silane grafting or peroxide crosslinking selected by the cable maker’s actual line. Production is executed on a co-rotating twin-screw extruder with L/D 40:1 or higher, with forced feeding of ATH in side stuffers and barrel temperatures capped at 140–170 °C; the strand pelletizer must use air cooling rather than water immersion to limit moisture uptake before silane grafting. Compliance is verified against IEC 60754-1:2011 for pH of combustion gases, IEC 60754-2:2011 for conductivity, IEC 61034-2:2019 for smoke density, and EN 50575:2014+A1:2016 for reaction to fire classification when the final cable is placed on the EU market. Terminal finished products include low-voltage building wire sheathing, control cable jackets, and fibre-optic riser cable sheaths. Processing boundaries are severe: ATH dehydration accelerates above 190 °C, so the batch must be held below that threshold even during start-up shear spikes; EVA 18J3 with 3.0 g/10 min MFI raises motor torque relative to MI 6 grades, and pre-drying at 60 °C for 2 h is required when moisture exceeds 500 ppm.
Pelletized additive concentrates containing 40–70 wt% carrier resin rely on EVA 18J3 when the downstream resin is LDPE or EVA film, and the final letdown ratio is maintained between 1–5 wt% of the compound being coloured or modified. The masterbatch process uses a co-rotating twin-screw extruder with L/D 36–44, screw speeds in the 300–600 rpm range, and a barrel profile of 150–180 °C; pigment or flame-retardant filler is introduced after the carrier melt seal, and vacuum venting at -0.08 MPa strips residual moisture from hygroscopic additives before the die plate. Compliance for packaging-related concentrates references FDA 21 CFR 177.1520 for olefin polymer resins when the finished article may contact food, and EU Regulation 10/2011 for plastic materials and articles in contact with food; colourimetric control for the concentrate incoming quality is reported against ISO 18314-2:2022. Terminal finished products include white masterbatches for blown film, flame-retardant concentrates for EVA/LDPE compounds, and slip/antiblock concentrates. EVA 18J3 is not a universal carrier: its 18 wt% vinyl acetate content lowers Vicat softening point relative to pure LDPE, so high-temperature film extrusion at barrel settings above 220 °C can increase backpressure and lead to plate-out on the die lip; when the concentrate is to be let down into thin-gauge cast film at 8–15 µm, published data for this specific configuration is limited and a pilot-scale trial is required before production commitment.
Greenhouse film production with EVA 18J3 in the middle co-extruded layer targets improved long-wave IR retention without shifting the skin-layer slip package; the EVA 18J3 content is held at 15–40 wt% of the middle layer, while the outer skins remain LLDPE/LDPE-rich. Processing on a three-layer blown film line uses a die gap of 1.8–2.4 mm, a blow-up ratio of 2.5–3.0, and a melt temperature of 180–200 °C; the air ring is set to 8–15 °C and the frost line is maintained 250–450 mm above the die to control crystallinity in the EVA-rich layer. Compliance for the agricultural film is verified under EN 13206:2017 for covering films used in horticulture, with tensile strength and elongation measured by ISO 527-3:2018 and ASTM D882-18, and the cultivation period specified by the film class selected by the buyer. Terminal finished products include multi-season greenhouse covers, low tunnel films, and propagation house sheeting. The formulation boundary is chemical rather than mechanical: EVA 18J3 begins deacetylation at sustained extruder temperatures above 230 °C, releasing acetic acid that corrodes downstream metal equipment and causes soot or gel specks; therefore a hydrotalcite acid scavenger is added at 0.05–0.20 phr and the line must be purged with LDPE before shutdown.
High-viscosity packaging and bookbinding hot melts incorporate EVA 18J3 at 28–38 wt% of the total formula, where the 3.0 g/10 min MFI limits excessive penetration into corrugated board while retaining the vinyl acetate comonomer needed for tackifier compatibility. The production process uses a heated sigma-blade mixer at 150–170 °C under a nitrogen blanket, with EVA 18J3 added after the tackifier melt has reached 130 °C and the hydrocarbon wax is dosed at 15–25 wt%; the finished blend is discharged through a heated gear pump to reduce thermal degradation during hold time. Compliance for food packaging adhesives is anchored to FDA 21 CFR 175.105, with apparent viscosity measured by ASTM D3236-15 at 180 °C and ring-and-ball softening point by ISO 4625-1:2020. Terminal finished products include case sealing adhesives, carton closing compounds, and bookbinding spine glues. Operational boundaries are specific: EVA 18J3 is unsuitable for low-temperature freezer-tape adhesives expecting flexibility below 5 °C, and adhesion to metalized or polar substrates is lower than with 28 wt% VA grades; amines should not be used as odour-mask additives because they can accelerate deacetylation and raise the melt colour index above 100 on the Gardner scale.
Injection moulded flexible parts based on EVA 18J3 are produced with the resin phase at 60–100 wt% of the polymer matrix, with calcium carbonate at 10–20 phr, paraffinic mineral oil at 5–15 phr when hardness must fall below 70 Shore A, and antioxidant at 0.2–0.5 phr. The moulding process uses a reciprocating screw with a 20:1 L/D barrel, temperature zones set to 150–180 °C, injection pressure of 65–90 MPa, and mould temperature held at 20–40 °C; clamp force is selected based on projected area and is typically 3.0–4.5 kN/cm² of the moulding surface. Compliance for exported components is validated against RoHS Directive 2011/65/EU and REACH Annex XVII, with tensile properties reported under ASTM D638-14 and hardness under ISO 868:2003 Shore A. Terminal finished products include vial seals, cable joint boots, vibration isolation pads, and appliance grommets. The processing limit is overheating: a melt soak above 180 °C for more than 5 min can initiate acetic acid release and raise the melt flow index above 4.0 g/10 min, causing flash and dimensional drift; mould shrinkage for EVA 18J3 compounds typically runs 1.5–2.5%, so gate and runner sizing must be determined from a shrinkage trial rather than generic LDPE guidelines.
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SINOPEC EVA 18J3 is an ethylene-vinyl acetate copolymer produced by China Petroleum & Chemical Corporation for injection moulding and chemically foamed product applications. The grade designation is interpreted from producer technical literature as a nominal vinyl acetate content of 18% by weight and a nominal melt flow rate of 3.0 g/10 min determined at 190°C under 2.16 kg load in accordance with ISO 1133-1:2022. Representative density is 0.940–0.945 g/cm³ at 23°C when measured according to ISO 1183-1:2019. The grade sits between low-VA general-purpose extrusion grades and high-VA high-softness grades, providing a balance of melt viscosity, flexibility, and gas-retention capacity during expansion. Principal usage areas reported by downstream processors include injection-moulded footwear components, industrial cushioning, shock-absorbing pads, gaskets, and foamed sheet fabricated by compression moulding or secondary expansion.
The product is not recommended for continuous high-speed extrusion of thin films on cast-film lines with haul-off speeds exceeding 100 m/min, because the molecular architecture is selected for melt strength and foam stability rather than draw-down and optical clarity. For those applications, higher-flow or film-grade EVA copolymers with lower molecular weight are generally specified.
The following representative data are derived from producer technical data and routine laboratory testing. Lot-to-lot variation is typically controlled within ±0.5 wt% for vinyl acetate content and ±0.3 g/10 min for melt flow rate. These tolerances are relevant for process-capability calculations; the certificate of analysis for a specific delivery lot remains the controlling specification.
| Property | Unit | Nominal value | Test method |
|---|---|---|---|
| Vinyl acetate content | % by weight | 18 | ISO 8985:1998 |
| Melt flow rate | g/10 min | 3.0 | ISO 1133-1:2022 |
| Density | g/cm³ | 0.940–0.945 | ISO 1183-1:2019 |
| Tensile strength at break | MPa | ≥14 | ISO 527-2:2012 |
| Elongation at break | % | ≥750 | ISO 527-2:2012 |
| Shore D hardness | Shore D | 40±2 | ISO 868:2003 |
| Vicat softening temperature A50 | °C | 60–65 | ISO 306:2022 |
| Melting peak temperature | °C | 82–86 | ISO 11357-3:2018 |
The injection moulding window for EVA 18J3 is governed by the competing requirements of complete cavity filling and avoidance of deacetylation. On production-scale injection moulding machines with a general-purpose polyolefin screw of 20:1 to 24:1 L/D and compression ratio 2.0–2.5:1, a starting melt temperature of 180–210°C is used. Barrel zones are commonly set with a rising profile from 130–150°C in the feed section to 180–200°C near the nozzle. A nozzle temperature below 210°C reduces premature decomposition of chemical blowing agents when a foam masterbatch is fed at the hopper. Mould surface temperatures of 20–40°C are typical for fast skin formation; higher mould temperatures above 45°C can extend cooling time and increase post-mould shrinkage.
Because EVA 18J3 contains 18 wt% vinyl acetate, thermal degradation at melt temperatures above 230°C releases acetic acid. This creates detectable odour, possible surface splay, and increased corrosion risk on unprotected carbon steel tool surfaces. The practical residence-time limit at 210°C is approximately 8–10 min during production interruptions; prolonged hold above 220°C should be avoided. Screw rotation and back pressure should be selected to avoid excessive shear heating. Back pressures of 0.5–1.5 MPa are usually sufficient for homogenisation; higher back pressures may raise melt temperature enough to shift the material toward deacetylation.
Pre-drying is not mandatory at ambient relative humidity below 50%. When storage conditions exceed 60% relative humidity or when moulded surface quality is critical, desiccant drying at 60–70°C for 4–6 h is recommended. Moisture above 0.05% by weight can produce silver streaks in thick sections. In multicavity tooling with cold-runner systems, cavity-to-cavity imbalance in runner temperature of more than 2°C can produce measurable differences in local foam density and part mass; hot-runner temperatures should be profiled to avoid dead spots and local overheating.
For multicavity injection moulding of foamed shoe soles, clamp force is usually calculated at 6–8 kN/cm² of projected area, depending on the target density and blowing agent dosage. Fill speeds of 50–150 mm/s are representative for medium-thickness sections; thinner sections may require higher speeds above 150 mm/s to prevent short shots, but excessive shear can reduce cell density.
In chemically blown injection foam, the melt-viscosity difference between EVA 18J3 and higher-flow EVA grades controls cell wall stability. At the same nominal vinyl acetate content of 18 wt%, EVA 18J3 has a lower melt flow rate than EVA 18J4; the lower flow produces greater melt strength during gas expansion and narrower cell-size distribution in thick sections. On industrial foam moulding equipment, azodicarbonamide blowing agent loadings of 1.5–3.0 phr are commonly used to achieve moulded foam densities of 0.15–0.30 g/cm³, provided the melt temperature at the nozzle is held near 200–210°C. Cell-size distribution can be verified by optical microscopy according to ASTM D3576-20. Published data for the specific lower limit of foam density in EVA 18J3 is limited; producer trials and compounder evaluations should be used to establish the exact blowing agent balance for each tool geometry.
Blowing agent activation is adjusted with zinc oxide or zinc stearate kickers. Zinc stearate at 0.5–1.5 phr can reduce the effective decomposition temperature of azodicarbonamide by 10–20°C, allowing expansion at a melt temperature below 210°C. This is beneficial for thick sections because premature skin formation and centre porosity are reduced. However, excessive kicker levels can produce over-blowing and surface blistering; therefore, the ratio of blowing agent to kicker should be controlled within 2:1 to 3:1 by weight.
Compared with EVA 14J2, which contains a nominal 14 wt% vinyl acetate and 2.0 g/10 min melt flow rate, EVA 18J3 yields lower Shore D hardness and improved low-temperature flexibility in moulded parts. Compared with EVA 28J6, a higher-softness grade with 28 wt% vinyl acetate and 6.0 g/10 min melt flow rate, EVA 18J3 provides higher tensile strength, higher dimensional stability, and lower blocking tendency, but lower oil resistance and less elastic recovery. These differences make EVA 18J3 a mid-range EVA for applications that require both mechanical integrity and foamability.
| Attribute | EVA 18J3 | EVA 18J4 | EVA 14J2 | EVA 28J6 |
|---|---|---|---|---|
| Nominal vinyl acetate content | 18% | 18% | 14% | 28% |
| Nominal melt flow rate | 3.0 g/10 min | 4.0 g/10 min | 2.0 g/10 min | 6.0 g/10 min |
| Representative Shore D hardness | 40±2 | 38±2 | 42±2 | 30±3 |
| Typical melt temperature range | 180–210°C | 170–200°C | 180–210°C | 160–190°C |
| Primary downstream process | Injection-moulded foam | Foam sheet and profile extrusion | General-purpose extrusion | Compounding, high-flexible moulding, hot-melt adhesives |
Mould shrinkage for EVA 18J3 in solid injection-moulded articles is normally in the range 1.2–1.8% along flow and 1.0–1.6% transverse to flow when measured after 48 h at 23°C according to ISO 294-4:2018. Foamed articles exhibit lower and less anisotropic shrinkage due to internal gas pressure; depending on density reduction, linear shrinkage can be 0.5–1.2%. Warpage is controlled by uniform gate location, balanced runner geometry, and mould temperature differentials below 5°C between fixed and moving halves.
Compared with LDPE homopolymer, the 18 wt% vinyl acetate comonomer reduces crystallinity, lowers Vicat softening point, and increases polarity. This confers better adhesion to polar substrates, greater low-temperature toughness, and broader compatibility with tackifier resins in adhesive formulations. It also reduces chemical resistance to strong acids and organic solvents and narrows the thermal processing window. Solvent resistance may be evaluated by mass change after immersion for 7 days at 23°C in accordance with ISO 175:2010.
In compounding operations, EVA 18J3 accepts high levels of calcium carbonate and other mineral fillers when sufficient shear is applied. On twin-screw extruders with an L/D of 40:1 or greater and screw speeds of 250–400 rpm, calcium carbonate loadings of 20–40 wt% can be dispersed without severe agglomeration. Barrel temperatures are normally profiled from 120°C to 160°C; operation above 180°C is unnecessary and can accelerate vinyl acetate degradation. The selection of filler particle size and surface treatment, rather than the polymer matrix alone, controls the final Shore D hardness and tear strength. Pre-coated stearic acid modified CaCO3 at median particle sizes of 2–5 µm provides lower die-pressure fluctuation than uncoated grades.
Peroxide crosslinking is applied in foam formulations to broaden the expansion window. The vulcanization kinetics of EVA/peroxide systems are controlled by the half-life decomposition of dicumyl peroxide; at 170°C the half-life is approximately 1 min, while at 150°C it is approximately 10 min. Dicumyl peroxide levels of 0.5–1.0 phr are typical for crosslinking EVA 18J3; the peroxide decomposition time should be matched to the blowing agent decomposition at 200–210°C. Insufficient peroxide leaves cell walls without elastic recovery, causing cell collapse; excessive peroxide raises gel content above 60–70% and produces over-cured regions with reduced elongation and embrittlement under cyclic compression. Gel content may be determined by solvent extraction or swelling in accordance with ASTM D2765-16.
Compatibility with amine-based additives is conditional. Amine-based antistatic or slip packages may interact with acetic acid formed during processing or service, generating carboxylate species and affecting colour and surface resistivity. Validation by thermogravimetric analysis coupled with Fourier transform infrared spectroscopy is recommended when such additives are introduced. Acid scavengers based on zinc stearate are commonly used at 0.05–0.2 phr to neutralise acidic residues without the same risk as basic amine packages. Polymer blending with LDPE or POE should be evaluated for phase morphology; EVA 18J3 is process-compatible with LDPE in typical proportions of 10–20 wt% LDPE for stiffness adjustment, but rapid cooling may induce phase separation above 30 wt%. Dispersed phase size can be verified by scanning electron microscopy after cryogenic fracture.
In food-contact applications, SINOPEC EVA 18J3 may be used as a component of articles intended for repeated contact with aqueous and acidic foods when the finished article complies with the extractives and end-use restrictions of 21 CFR 177.1350 and, where relevant, EU Regulation (EU) No 10/2011 on plastic materials and articles intended to come into contact with food. Compliance must be assessed on the finished article, not on the raw resin alone; migration testing under EN 1186 methods or total migration limits of 10 mg/dm² may apply depending on the food simulant. Higher vinyl acetate content increases polarity and can alter additive migration kinetics; therefore, the 18 wt% VA grade should be tested with the intended simulant rather than assumed equivalent to lower-VA olefins.
Total migration testing is commonly performed with simulant 3% w/v acetic acid or 10% v/v ethanol depending on the intended food type, under repeated-use conditions of 2 h at 70°C for aqueous foods. This test condition is more severe than ambient use and provides a conservative estimate of additive migration.
Electrical and electronic market applications are outside the principal use envelope for this grade. If EVA 18J3 is used in appliance components, the finished component should be evaluated against IEC 60695-11-10 for flammability class, typically HB for unfilled EVA, and against IEC 62321 procedures for RoHS verification under Directive 2011/65/EU. The unfilled resin does not contain intentionally added lead, cadmium, mercury, hexavalent chromium, PBB, or PBDE above the maximum concentration values, but the final compound can change this status due to pigments, fillers, or flame retardants.
For toys and childcare articles, migration of specific elements should be assessed according to EN 71-3:2019, not only total heavy-metal content. The resin does not provide inherent flame retardancy; where a final article is required to meet UL 94 V-0, the addition of intumescent or halogen-free flame retardants can alter mechanical and foaming characteristics and must be validated on production tooling.
Under REACH Regulation (EC) No 1907/2006, SINOPEC EVA 18J3 as a polymer is exempt from registration obligations under Article 2(9), provided its constituent monomers are registered as required. Documentation duties for substances of very high concern in articles under Article 33 remain applicable if the final compound contains SVHC above 0.1% w/w. The grade is not supplied with implant-grade certification; for medical device components, ISO 10993-1:2018 biological evaluation is not automatically satisfied by raw resin compliance, and finished article testing is required.
