| HS Code | 135028 |
| Polymer Type | Ethylene-Vinyl Acetate (EVA) Copolymer |
| Aldehyde Content | Low (≤5 ppm) |
| Vam Content | 28% by weight |
| Clarity | Ultra-clear / High light transmittance |
| Tensile Strength | ≥20 MPa |
| Elongation At Break | ≥750% |
| Melt Flow Index | 15 g/10 min (190°C/2.16 kg) |
| Hardness | Shore A 85 |
| Softening Point | ≥80°C |
| Uv Resistance | Excellent / High stability |
| Odor | Nearly odorless |
| Optical Haze | ≤1% |
As an accredited Low-Aldehyde Special Polymer VAM (Ultra-Clear Top-Tier EVA) factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Supplied in 25 kg multi-layer moisture-proof bags with inner liners, preserving ultra-clear, low-aldehyde EVA quality during storage and transport. |
| Container Loading (20′ FCL) | Loaded in 20′ FCL, 25 kg bags on shrink-wrapped pallets, secured for transit. Safe, dry, upright handling ensures product integrity. |
| Shipping | Shipped in sealed, moisture-resistant multi-layer bags or drums to preserve ultra-clear properties. Store in a cool, dry, well-ventilated area away from heat, sparks, and strong oxidizers. Protect packaging from damage during loading and unloading. Use appropriate PPE and avoid inhalation of dust. |
| Storage | Store in a cool, dry, well-ventilated area away from direct sunlight, heat sources, and ignition. Keep container tightly sealed to prevent moisture absorption and contamination. Avoid contact with strong oxidizers, acids, and bases. Maintain stable temperatures between 5–30°C. Use appropriate PPE when handling, and follow local regulations for safe disposal. |
| Shelf Life | Shelf life is 12 months from manufacture when stored sealed, cool, and dry, away from sunlight and contamination. |
In photovoltaic encapsulant film manufacturing, low-aldehyde special polymer VAM, supplied as an ultra-clear top-tier EVA, is charged at 100 phr with a peroxide initiator window of 0.6–1.2 phr, vinyltrimethoxysilane adhesion promoter at 0.3–0.5 phr, hindered phenol/phosphite stabilizer at 0.15–0.4 phr, and UV absorber at 0.1–0.3 phr. The compound is extruded on a single-screw cast film line with barrel set points 85–105°C, adapter 105°C, and flat die 100–120°C; film thickness is maintained at 0.45–0.80 mm with a gauge tolerance of ±5% using gravimetric feeding. The terminal product is the encapsulation layer for single-glass and glass-glass modules using PERC, TOPCon, or heterojunction cells, where the film must exhibit post-lamination light transmittance above 91% by IEC 62788-1-4:2016, yellowness index below 1.5 by ASTM E313-20, and gel content of 72–89% by ASTM D2765-16 after laminator cure at 145°C for 18 min. Module-level qualification requires passing IEC 61215-2:2021 MQT 12 thermal cycling of 200 cycles from -40°C to +85°C and MQT 13 damp heat at 85°C/85% RH for 1000 h.
| Formulation variable | Operating range | Measured response after lamination | Test method / equipment |
|---|---|---|---|
| EVA base resin, 28 wt% vinyl acetate | 100 phr | Melt flow rate 15–30 g/10 min at 190°C/2.16 kg | ISO 1133-1:2022 |
| tert-butyl peroxy-2-ethylhexyl carbonate | 0.6–1.2 phr | Gel content 72–89% after 145°C, 18 min | ASTM D2765-16 |
| Vinyltrimethoxysilane | 0.3–0.5 phr | Glass adhesion retained after 1000 h damp heat | IEC 61215-2:2021 MQT 13 |
| Hindered phenol/phosphite package | 0.15–0.4 phr | Yellowness index increase <1.0 after 15 kWh/m² UV | IEC 62788-1-4:2016; ASTM E313-20 |
The critical processing boundary occurs at the flat die lip. Above 205°C, the peroxide initiator undergoes premature decomposition; gel specks larger than 0.1 mm² form in the cast film and appear as optical defects after lamination. Below 185°C, edge melt stiffness increases, causing gauge variation beyond ±7% at a 2.2 m die width. Production-scale lines therefore hold the die lips at 190–200°C, a control window of approximately ±5°C after line stabilization. Low-aldehyde control reduces acetaldehyde and propionaldehyde in the module headspace; the resin specification typically requires residual aldehyde below 15 mg/kg by HPLC following 2,4-dinitrophenylhydrazine derivatization. Published comparative data for aldehyde outgassing from this exact ultra-clear grade during long-term UV exposure is limited; incoming resin is qualified against the above formulation window rather than referenced from generic EVA data.
In coextruded flexible packaging, low-aldehyde EVA is introduced into the food-contact sealant skin at 10–25 wt% relative to the skin layer, blended with metallocene LLDPE of density 0.918–0.922 g/cm³ and melt flow rate 0.5–1.5 g/10 min; a core layer of LLDPE or LDPE supports the structure, and a tie layer may contain 3–7 wt% maleic anhydride–grafted EVA. The structure is produced on a three-layer blown film line with die diameter 250–400 mm, die gap 1.5–2.2 mm, blow-up ratio 2.0–3.0, frost line height 6–8 die diameters, and melt temperature 180–210°C. The sealant layer complies with FDA 21 CFR 177.1350, and the finished film must pass overall migration and specific migration of vinyl acetate and aldehydes under Commission Regulation (EU) No 10/2011 as amended, evaluated in simulant A 10% ethanol, simulant B 3% acetic acid, and simulant D2 for fatty foods. Terminal products include fresh-cut produce bags, bakery films, liquid-pouch sealant webs, and frozen food lidding films. Increasing EVA from 10 wt% to 25 wt% lowers seal initiation temperature by approximately 2–4°C per 5 wt% increment, but at levels above 25 wt% the aldehyde and acetate carryover rises after 7 days at 40°C, creating sensory failure risk in high-fat products. The low-aldehyde grade is specified to keep residual acetaldehyde below 15 mg/kg after film production, measured by HPLC with DNPH derivatization; die lip accumulations and headspace taint become measurable at melt temperatures above 220°C.
Hot-melt adhesive compounding uses low-aldehyde EVA as the base polymer at 18–40 wt%, with 30–50 wt% hydrogenated rosin ester or C5/C9 tackifier, 10–30 wt% paraffin or Fischer-Tropsch wax, and 0.3–1.0 wt% phosphite antioxidant. The addition ratio is bounded on the lower end by insufficient cohesive strength at 18 wt% and on the upper end by Brookfield viscosity exceeding 2500 mPa·s at 180°C, which limits slot-die pumping. Compounding is performed in a sigma-blade mixer at 150–170°C under vacuum below -0.09 MPa for 1.5–2.5 h, discharged through a single-screw extruder with L/D 12:1–20:1 into a water-cooled pelletizer. The adhesive is applied by roll coaters or slot dies at 150–180°C, with open time 5–15 s, set time 3–10 s, and viscosity controlled at 400–2500 mPa·s by ASTM D3236-17; ring-and-ball softening point is maintained at 85–110°C by ASTM E28-18. Terminal products include carton closing, bookbinding, furniture edge-banding, and filter frame assembly adhesives. When used in packaging with indirect food contact, the adhesive is qualified under FDA 21 CFR 175.105; low-aldehyde content reduces the potential for odor pickup in dry foods and lowers worker exposure during high-temperature open mixing. Published data for specific aldehyde emission reductions in this configuration remain limited, so incoming resin is profiled by HPLC after melt hold at 170°C for 2 h.
In medical packaging coextrusion, low-aldehyde EVA is dosed into the sealant layer at 15–30 wt%, coextruded with ULDPE or LDPE outer layers on a cast line with 3-layer or 5-layer feedblock, die width 1.2–1.8 m, total film thickness 60–120 µm, and chill roll temperature 15–25°C. The EVA-containing web is heat-sealed at 115–140°C, dwell 0.5–1.5 s, and jaw pressure 0.4–0.7 MPa, producing peelable seals against uncoated Tyvek or medical paper. The finished sterile barrier system is validated under ISO 11607-1:2019; biocompatibility is established by ISO 10993-5:2009 cytotoxicity testing and USP Class VI extraction, and leachables profiling is performed according to ISO 10993-18:2020. Terminal products are preformed pouches, header bags, and lidding films for syringes, catheters, and surgical kits, sterilized by ethylene oxide or gamma irradiation at 25–50 kGy. The low-aldehyde VAM-sourced EVA is specified for reduced extractable aldehydes in water and aqueous alcohol leachates; above 50 kGy gamma dose, EVA containing more than 28 wt% vinyl acetate may undergo chain scission that increases acetic acid and unsaturated aldehyde species, raising the risk of seal embrittlement and pH shift in contact solutions.
Extrusion coating lamination lines running high-speed barrier sealant webs blend low-aldehyde EVA into the sealant layer at 10–35 wt% with LDPE of melt flow rate 7–15 g/10 min, applied to aluminum foil, metallized BOPET, or BOPP at a coating weight of 12–25 g/m². The line is operated with a single-screw extruder L/D 30:1, barrel profile 180–260°C, adapter 260°C, slot die 260°C, air gap 150–300 mm, line speed 150–400 m/min, and chill roll temperature 15–25°C. The sealant web complies with FDA 21 CFR 177.1350 and Commission Regulation (EU) No 10/2011 as amended for specific migration of vinyl acetate and aldehydes in simulant D2; terminal products include liquid aseptic cartons, snack laminations, and retort pouch sealant layers. The operating window at the die is narrow: at melt temperature above 275°C, acidolysis and deacetylation produce acetic acid, acetaldehyde, and crotonaldehyde, leading to smoke, die lip deposits, and odor complaints; below 235°C, draw resonance and edge neck-in become severe at speeds above 250 m/min. The recommended melt temperature of 250–260°C represents a ±5°C control window when EVA exceeds 30 wt% in the sealant layer. Published data for this exact low-aldehyde grade in retortable structures at 121°C overpressure processing remain limited.
In architectural laminated glass interlayer manufacturing, low-aldehyde special polymer VAM is processed as an ultra-clear EVA film with a base formulation of 100 phr EVA, 0.3–0.6 phr vinyltrimethoxysilane adhesion promoter, 0.1–0.3 phr hindered phenol/phosphite antioxidant, and 0.05–0.15 phr UV absorber; no plasticizer is required. The film is cast or calendered at barrel temperatures 90–140°C, die 130–150°C, and thickness 0.25–1.0 mm, then bonded between glass lites in a vacuum bag or autoclave at 120–160°C and 0.8–1.2 MPa for 30–90 min. Laminated glass made with this interlayer is specified under EN ISO 12543-2:2021 and ANSI Z97.1-2015, with yellowness index measured by ASTM E313-20 and haze by ASTM D1003-21. Terminal products include decorative laminated safety glass, shower enclosures, glass floor treads, and sound-control glazing systems. The low-aldehyde characteristic reduces bubble nucleation and haze formation during long autoclave dwells; residual aldehyde content above 20 mg/kg in the film correlates with visible edge bubbles of 0.2–0.5 mm when the laminate is heated above 140°C. Pre-drying at 60°C for 4 h to a dew point below -40°C is required when storage relative humidity exceeds 60%.
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Low-Aldehyde Special Polymer VAM (Ultra-Clear Top-Tier EVA) is a pelletized ethylene-vinyl acetate copolymer resin with a vinyl acetate comonomer content controlled to 28.0 wt% as measured by ASTM D5594-18. The VAM designation refers to the vinyl acetate monomer-derived comonomer segment, not to a separate vinyl acetate monomer product. The grade is supplied for cast film, extrusion coating, and laminating processes in which residual aldehydes, optical haze, and color shift are controlled parameters. Published data for this specific configuration is limited; the values reported here are representative lot data and are not a universal specification.
Melt flow rate is controlled to 25.0 g/10 min at 190°C under 2.16 kg load per ISO 1133-1:2022. Density is 0.950 g/cm³ per ISO 1183-1:2019. The low-aldehyde profile is achieved through high-temperature degassing and a non-amine stabilization package, with total aldehyde release kept below 5 µg/g in an extraction at 60°C for 3 h. Conventional EVA film grades of equivalent vinyl acetate content typically fall between 15 µg/g and 60 µg/g under the same extraction conditions.
Formaldehyde emission in automotive interior trim is measured according to VDA 275, and total volatile organic compound release is determined by headspace gas chromatography-mass spectrometry per VDA 277. The grade is accepted when total aldehydes do not exceed 5 µg/g in extraction at 60°C for 3 h. Acetaldehyde is the dominant carbonyl species; formaldehyde remains below 1 µg/g in typical lots. Conventional EVA of equivalent 28 wt% vinyl acetate content often shows acetaldehyde values from 15 µg/g to 60 µg/g, depending on degassing history and antioxidant load. This difference is the primary reason for selecting the low-aldehyde grade in vacuum-formed automotive skins where aldehyde fogging can condense on glazing.
Optical performance is measured on 0.50 mm compression-molded plaques. Luminous transmittance per ASTM D1003-21 is not less than 91.5%, haze is not greater than 1.8%, and yellowness index per ASTM E313-20 remains below 1.2. Amine-based additives are excluded from the formulation because amine-carbonyl condensation can increase haze after storage at 60°C for 14 days.
| Property | Test method | Unit | Low-Aldehyde VAM | Conventional EVA |
|---|---|---|---|---|
| Vinyl acetate content | ASTM D5594-18 | wt% | 28.0 | 28.0 |
| Melt flow rate | ISO 1133-1:2022 | g/10 min | 25.0 | 25.0 |
| Density | ISO 1183-1:2019 | g/cm³ | 0.950 | 0.950 |
| Tensile strength at break | ISO 527-2:2012 | MPa | 15.0 | 14.0 |
| Elongation at break | ISO 527-2:2012 | % | 750 | 700 |
| Luminous transmittance | ASTM D1003-21 | % | 91.5 | 90.0 |
| Haze | ASTM D1003-21 | % | 1.8 | 3.5 |
| Yellowness index | ASTM E313-20 | — | 1.2 | 2.8 |
| Total aldehyde release | VDA 275, 60°C extraction | µg/g | ≤5 | 15–60 |
Differentiation from other products is therefore not based on vinyl acetate content or melt flow rate, but on residual aldehyde load, stabilizer chemistry, and optical haze control. The grade is interchangeable with conventional EVA in downstream equipment but requires revalidation of odor-sensitive and optical applications.
In film optical inspection, gel counts above 100 µm are controlled to fewer than 2 counts per 1000 m² using a CCD camera system. Gel origins include microgels from high-temperature initiator residues and partially hydrolyzed vinyl acetate domains. The low-aldehyde grade is filtered through a 20 µm screen pack during manufacture to reduce gel seeds. In conventional EVA, gel-induced haze can increase when the resin is stored above 30°C for prolonged periods; this grade is shipped in sealed, moisture-barrier packaging to limit the same effect.
On a 65 mm single-screw extruder with a 30:1 L/D ratio and a 1200 mm coat-hanger die, barrel zones are set from feed to metering at 140°C, 160°C, 175°C, and 180°C. Adapter and die zones are held at 185°C and 190°C, and melt temperature measured by an immersion probe is maintained below 200°C. The processing window is narrow: increasing die temperature above 210°C accelerates vinyl acetate deacetylation, releasing acetic acid and regenerating carbonyl species, while decreasing barrel temperature below 150°C increases melt viscosity and can overload the extruder drive at screw speeds above 40 min⁻¹. Edge gel accumulation on the die lip is observed after 6 h of continuous operation when die lip heaters oscillate beyond ±3°C; this failure mode is specific to cast film lines with long residence time at die edges.
Screen pack pressure differential across the breaker plate is monitored, and a rise exceeding 15 bar indicates gel or contaminant accumulation requiring a screen change. Pre-drying in a desiccant dryer at 60°C for 4 h to a dew point of −40°C is required when ambient relative humidity exceeds 60%. Insufficient drying produces surface bubbles, increased aldehyde content after regranulation, and melt pressure fluctuation exceeding ±8%. Lot-to-lot melt flow rate is controlled within ±1.5 g/10 min to limit thickness variation in cast film. Film thickness across a 1200 mm die is maintained at ±5% by automatic die bolt adjustment.
Differential scanning calorimetry at 10°C/min per ISO 11357-3:2018 shows a melting endotherm peak at 62°C and a crystallization exotherm peak at 48°C. Chill roll temperature below 15°C is necessary to prevent blocking because crystallization is slow. Oxidation induction time at 200°C is specified above 20 min by ISO 11357-6:2018.
Injection molding of the grade for transparent medical connectors requires a mold temperature between 20°C and 40°C. Screw back pressure is set at 5–10 bar, and holding pressure is maintained at 50–70% of injection pressure. The melt cushion is held at 3–5 mm. Processing above 200°C increases aldehyde reformation in the molded part; low-aldehyde performance is maintained only when melt temperature and residence time are controlled. Mold release agents containing stearic acid are acceptable at low loading, but amine-based antistatic additives are not permitted. Residence time above 10 min can shift the aldehyde profile even at 180°C; repeated start-stop operation should be minimized.
Photovoltaic encapsulant film is produced by cast extrusion with downstream peroxide masterbatch dosing at 1.0–1.5 wt%. The low-aldehyde grade reduces volatile carbonyl release during the initial vacuum pull-down, limiting bubble entrapment at the glass–EVA interface. Lamination in a vacuum laminator uses a platen temperature of 150°C, chamber vacuum of 40 kPa, and dwell time of 8 min. Gel content after lamination, measured by extraction in boiling xylene per ASTM D2765-16, reaches 75–85%. Cure below 145°C leaves gel content below 60%, increasing long-term delamination risk; cure above 165°C increases acetic acid split-out and can reduce adhesion to glass. Adhesion to glass after lamination is measured by tensile peel per ASTM D903-98, with values typically between 40 N/cm and 70 N/cm.
The grade is used in glass–backsheet and glass–glass modules. After damp heat exposure at 85°C and 85% relative humidity for 1000 h per IEC 61215-2:2021, yellowness index increase is targeted to remain below 2.0 when the film is laminated with low-iron glass and a non-antimony UV-stabilized encapsulant package. Published data for bifacial glass–glass field performance beyond 10 years is limited.
In medical tubing, irradiation sterilization can regenerate carbonyl species. The grade is evaluated for extractables by ISO 10993-18:2020 chemical characterization and is used where acetaldehyde migration into aqueous simulants must remain below 2 µg/g. Gamma irradiation at 25 kGy increases total aldehydes by less than 2 µg/g, whereas conventional EVA of equivalent vinyl acetate content can increase by 10–20 µg/g under the same dose. Published data for this specific configuration is limited for irradiation doses above 50 kGy.
In food-contact applications, the base polymer falls under FDA 21 CFR 177.1350 for ethylene-vinyl acetate copolymers, provided the final article meets the extractives and end-use restrictions of that section. Compliance with RoHS 2011/65/EU is documented for lead, mercury, cadmium, hexavalent chromium, PBB, and PBDE. Heavy metal migration is below limits in Commission Regulation (EU) No 10/2011 when tested by inductively coupled plasma mass spectrometry under 10% ethanol and 3% acetic acid simulants. Food-contact compliance must be established by the converter under final article conditions; the resin supply certificate alone does not establish food-contact status.
The grade is not recommended for use with amine-based antistatic additives, organotin stabilizers, or acidic purge compounds. Processing with PVC or chlorinated paraffins should be avoided because acetic acid release increases and can corrode downstream metal surfaces. Storage in sealed original packaging at 5°C to 30°C is recommended for up to 12 months. After 30 days of open storage, re-drying is required if ambient relative humidity exceeds 60%.
