| HS Code | 540564 |
| Chemical Name | Vinyl Acetate Monomer |
| Cas Number | 108-05-4 |
| Molecular Formula | C4H6O2 |
| Molecular Weight | 86.09 g/mol |
| Appearance | Clear colorless liquid |
| Purity | ≥99.9% |
| Boiling Point | 72.7°C at 101.3 kPa |
| Melting Point | -93°C |
| Flash Point | -8°C (closed cup) |
| Density | 0.932 g/cm³ at 20°C |
| Viscosity | 0.43 mPa·s at 20°C |
| Water Content | ≤0.05% |
| Acidity As Acetic Acid | ≤0.005% |
| Acetaldehyde Content | ≤0.01% |
| Hydroquinone Inhibitor | 3-7 ppm |
| Solubility In Water | ~20 g/L at 20°C |
| Refractive Index | 1.395 at 20°C |
| Vapor Pressure | 11.5 kPa at 20°C |
| Autoignition Temperature | 427°C |
| Food Contact Compliance | Suitable for food contact applications per FDA 21 CFR and EU 10/2011 |
As an accredited Wanwei VAM FC Food Contact Compliant Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Packaged in 200 kg steel drums or 1,000 kg IBC totes, ensuring food-safe integrity and easy handling. |
| Container Loading (20′ FCL) | One 20′ FCL of Wanwei VAM FC Food Contact Compliant Grade, securely drummed and palletized for safe transport. |
| Shipping | Ship as UN 1301, Vinyl acetate, inhibited (Class 3, PG II). Use dedicated, thoroughly cleaned ISO tanks or drums to preserve Wanwei VAM FC food-contact compliance. Maintain nitrogen blanket, avoid moisture/contamination and ignition sources. Follow IMDG/ADR regulations; placard, document, secure cargo, and protect from heat during transit. |
| Storage | Store in a cool, dry, well-ventilated area away from direct sunlight, heat, flames, and incompatible oxidizers. Keep containers tightly sealed to prevent moisture ingress and evaporation. Maintain recommended storage temperature, avoid prolonged exposure to air to prevent polymerization, and ensure proper bonding/grounding. Use approved materials for containers and inspect regularly for leaks or degradation. |
| Shelf Life | Shelf life: 12 months from manufacture when stored sealed, cool, and dry per specifications. |
Ethylene-vinyl acetate copolymers synthesized from vinyl acetate monomer with a food contact compliance envelope are used as sealant layers in coextruded flexible packaging. In high-pressure autoclave and tubular low-density polyethylene lines, the vinyl acetate monomer feed ratio is controlled to produce vinyl acetate incorporation levels between 4 wt% and 12 wt% for sealant grades and up to 28 wt% for high-cling films; this incorporation suppresses polyethylene crystallinity and shifts heat-seal initiation temperature downward by roughly 2–4 K per wt% VA, as measured by differential scanning calorimetry according to ASTM D3418-21. The regulatory route for the United States is 21 CFR 177.1350, while European compliance requires that any residual vinyl acetate migrating from the final film does not exceed the specific migration limit set out in EU 10/2011 Annex I at 12 mg/kg in food simulants. Production-scale coextrusion on multi-layer blown film lines with die gaps between 1.4 mm and 2.2 mm has shown a recurring failure mode: at vinyl acetate contents above 18 wt%, the film surface becomes tacky on the collapsing frame, causing chatter and blocking in the winder unless the film enters the nip with a chill-roll temperature below 28 °C and anti-fog/antiblock masterbatch is dosed at 0.5–1.2 wt%. End products include lidding films for ready-meal trays, frozen food pouches, and vertical form-fill-seal package interiors, where the VAM-derived ethylene-vinyl acetate layer is not exposed directly to the food in many structures but is covered by an additional food-contact tie or sealant layer.
In continuous solution polymerization for chewing gum base, polyvinyl acetate is produced from VAM by free-radical polymerization in methanol, followed by vacuum stripping to reduce residual monomer below levels dictated by 21 CFR 172.615. The compounded gum base typically incorporates polyvinyl acetate at 10–35 wt% as a hydrophobic masticatory texture modifier, while the weight-average molecular weight is controlled between 12,000 Da and 55,000 Da to tune elasticity, cold flow, and chew release. Mixing is carried out in heated sigma-blade or Banbury-type compounders with jacket oil temperatures between 110 °C and 130 °C, where torque monitoring is used to detect batch-to-batch drift in polymer molecular weight; a variation of more than ±7% in mixer torque against the reference recipe has been associated with unacceptable changes in final chew texture and stickiness. The finished gum base must meet extraction limits under 21 CFR 172.615, and although vinyl acetate monomer is not the primary compliance variable because it is consumed during polymerization, residual monomer content is reduced by stripping to a level consistent with good manufacturing practice. Published data for exact residual vinyl acetate levels in specific commercial gum base recipes is limited; final compliance is determined by extraction testing under the cited regulation rather than by a single published monomer ceiling. Terminal product types include chewing gum sticks, coated gum pellets, and gum bases supplied to confectionery manufacturers for direct food use.
PVOH synthesized from food-contact VAM via catalyzed methanolysis is applied as a waterborne oxygen barrier layer on polyester or polypropylene substrates. The coating formulation typically consists of 8–12 wt% PVOH solids in deionized water, with a viscosity between 200 mPa·s and 1,200 mPa·s at 25 °C, depending on the 4% solution viscosity of the PVOH grade; degree of hydrolysis is held between 88 mol% and 99 mol% to balance water resistance and oxygen barrier. Slot-die or gravure coating at 30–80 m/min line speed requires drying air below 120 °C to avoid film skinning, and the dry coating weight is controlled between 0.3 g/m² and 1.5 g/m². Oxygen transmission rate is measured under ASTM D3985-17 at 23 °C and 0% RH, with values below 0.5 cm³/m²/day reported for high-barrier PVOH-coated PET; at 75% RH, the barrier deteriorates unless a topcoat is applied. Compliance in the U.S. is addressed under 21 CFR 177.1670 for polyvinyl alcohol film and 21 CFR 175.300 for resinous and polymeric coatings; in the EU, the finished film must satisfy overall migration and the vinyl acetate specific migration limit of 12 mg/kg under EU 10/2011. Production-scale failure modes include foaming in the coating pan when PVOH solution is recycled without defoaming and rheology drift from microbial degradation in water-based batches stored beyond 48 h without biocide. End products include pouches for dry cereals, nuts, dehydrated dairy ingredients, and oxygen-sensitive powdered formulations.
For carton side-seam and cup-forming adhesives, vinyl acetate-ethylene emulsions are manufactured by free-radical emulsion polymerization in continuous stirred-tank reactors with vinyl acetate comprising 70–85 wt% of total monomer and ethylene making up the balance under pressures of 30–70 bar. The emulsion solids content is controlled between 55–65 wt% for laminating adhesives, with Brookfield viscosity at 20 rpm typically between 1,500 mPa·s and 4,500 mPa·s at 23 °C; pH is maintained between 4.5 and 6.0 using sodium acetate or sodium bicarbonate. Regulatory status for the adhesive application is established through 21 CFR 175.105 for food-contact adhesives and, when used in paperboard, 21 CFR 176.170 or 21 CFR 176.180 depending on the food type; EU compliance requires residual vinyl acetate below the 12 mg/kg specific migration limit in EU 10/2011. Application on high-speed carton side-seam lines at 300–600 m/min has shown a repeated bottleneck: starved ethylene feed during reactor operation generates coarse particles with grit above 150 µm, blocking the 60 µm nozzle filters and causing adhesive skip in the wheel applicator. End products include beverage carton side seams, spiral-wound containers, frozen food cartons, and paper cup bottoms, where the adhesive is outside the food contact layer but is subject to the same extractives discipline due to set-off through the paperboard.
| VAM-derived polymer system | U.S. food contact citation | EU harmonized citation | Monomer/residual control criterion |
|---|---|---|---|
| Ethylene-vinyl acetate sealant resin | 21 CFR 177.1350 | EU 10/2011 | Vinyl acetate SML 12 mg/kg |
| Polyvinyl acetate chewing gum base | 21 CFR 172.615 | No harmonized EU chewing gum base list; national provisions apply | Residual vinyl acetate controlled by monomer stripping; no harmonized SML |
| Polyvinyl alcohol barrier coating | 21 CFR 177.1670, 21 CFR 175.300 | EU 10/2011 | Vinyl acetate SML 12 mg/kg |
| Vinyl acetate-ethylene adhesive | 21 CFR 175.105, 21 CFR 176.170 | EU 10/2011 | Vinyl acetate SML 12 mg/kg; emulsion residual monomer limited by process stripping |
| EVOH barrier resin | 21 CFR 177.1360 | EU 10/2011 | Vinyl acetate SML 12 mg/kg |
| Water-soluble PVOH film | 21 CFR 177.1670 | EU 10/2011 | Vinyl acetate SML 12 mg/kg |
When VAM is copolymerized with ethylene at high vinyl acetate molar fractions and the resulting EVA is subjected to base-catalyzed methanolysis, the product is ethylene-vinyl alcohol copolymer used as an oxygen barrier in multilayer coextrusions. The precursor EVA must carry a vinyl acetate molar fraction between roughly 56 mol% and 73 mol% to yield EVOH with ethylene contents from 27 mol% to 44 mol% after saponification; the hydrolysis conversion is driven above 99% using sodium methoxide in methanol, and residual acetate groups below 1 mol% are necessary to avoid gelation during subsequent film extrusion. Compliance is anchored to 21 CFR 177.1360 for ethylene-vinyl acetate-vinyl alcohol copolymers and, in Europe, the finished multilayer film must meet EU 10/2011 overall migration and the vinyl acetate specific migration limit of 12 mg/kg. In production, EVOH barrier layers are coextruded at melt temperatures between 210 °C and 250 °C, with a barrier layer thickness between 3 µm and 8 µm; blow-up ratios above 2.5:1 can introduce interlayer instability when EVOH viscosity deviates by more than ±10% from the adjacent polyolefin tie layers. A documented plant-scale failure mode involves incomplete catalyst neutralization after saponification, which accelerates thermal degradation in the extruder and produces black specks at 250 °C when residence time exceeds 5 min. Terminal products include retort pouches, vacuum skin pack for processed meat and cheese, aseptic brick cartons, and oxygen-sensitive nutritional powder packaging.
Water-soluble PVOH film made from food-contact VAM is used as a sacrificial packaging layer for pre-portioned dry food ingredients that are added directly to hot or cold aqueous processing. The film is cast from an aqueous solution containing 15–22 wt% PVOH solids and plasticizer levels between 10 wt% and 20 wt% of dry polymer, typically glycerol or sorbitol selected for food contact compliance; dissolution at 20 °C is governed by degree of hydrolysis and plasticizer content, with grades at 88 mol% dispersing rapidly and grades at 99 mol% requiring temperatures above 60 °C. The forming process uses a continuous steel belt or chill-roll dryer with circulating air between 80 °C and 120 °C, and film moisture is conditioned to 8–12 wt% before slitting. Compliance for direct food contact is supported by 21 CFR 177.1670 for polyvinyl alcohol film, while EU migration requirements are checked under EU 10/2011 with the vinyl acetate specific migration limit of 12 mg/kg. Production-scale failure modes: below 35% RH the film becomes brittle and cracks at crease; above 65% RH it blocks and delaminates, so slitting rooms require humidity control at 45–55% RH. Terminal product forms include soluble sachets for pre-weighed dry seasonings, instant beverage powders, starch thickeners, and portion-controlled enzyme mixes, where the film dissolves in the food preparation liquid and carries no peel tab or secondary waste.
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The product designated Wanwei VAM FC Food Contact Compliant Grade is vinyl acetate monomer (CAS 108-05-4) supplied with a controlled impurity profile for polymerisation operations in which the resulting polyvinyl acetate, ethylene-vinyl acetate copolymer, or polyvinyl alcohol is intended to become part of a food-contact article. Vinyl acetate monomer is not itself a direct food additive or finished food-contact material; suitability is demonstrated only after polymerisation, compounding, conversion, and extraction testing on the finished article under the relevant national or regional requirements. The FC designation is applied at the monomer stage to reduce the extractable aldehyde, heavy-metal, and stabiliser burden transferred into downstream polymers.
In a split-stream VAM purification train, the principal separation points affecting food-contact suitability are the light-ends column, where acetaldehyde and methyl acetate are removed, and the heavy-ends column, where acetic acid, crotonaldehyde, and higher ketones are rejected. Technical-grade VAM can carry acetaldehyde at concentrations that act as a chain-transfer agent in radical polymerisation; at addition levels above 20–50 mg/kg, depending on initiator concentration and temperature, the molecular weight distribution shifts downward and increases low-molecular-weight extractables in the finished polymer. The FC grade is specified with an aldehyde ceiling below this polymerisation-sensitive window and with a hydroquinone inhibitor content maintained within a narrower band than general-purpose monomer. Conformance to ASTM D2190-07(2021) for assay, water, acidity, color, and inhibitor is retained, but supplementary analysis of aldehydes by headspace gas chromatography is required because ASTM D2190 does not establish a food-contact-specific aldehyde limit. This gap is material in PVAc dispersion production: low-molecular-weight fractions generated by chain transfer can increase the non-volatile extractable matter observed during EU 10/2011 overall migration testing, particularly in fatty-food simulants such as ethanol 95% or isooctane.
Acetaldehyde in VAM arises not only from incomplete light-ends separation but also from oxidative degradation pathways initiated by trace iron and copper during storage and transfer. The metals catalyse decomposition of hydroperoxide intermediates to low-molecular-weight carbonyl species, so the FC specification adds an elemental screen that is typically absent from general-purpose monomer release. Water and acidity are not independent variables: water ingress combined with free acetic acid accelerates hydrolysis of VAM to acetaldehyde and acetic acid, further increasing the carbonyl load before polymerisation. The FC grade therefore maintains water and acidity limits that are lower than the upper boundaries permitted in ordinary technical specifications, reducing the driving force for acid-catalysed hydrolysis during extended railcar or isotainer residence time. Colour is controlled in platinum-cobalt units because early colour development in VAM frequently indicates advanced oxidation or metal contamination that may not yet be visible in assay loss.
| Property | Control basis | Reference method |
|---|---|---|
| Vinyl acetate assay | ≥ 99.9% by mass | ASTM D2190-07(2021) |
| Water content | ≤ 0.05% by mass | ASTM D1364-02(2012) / Karl Fischer |
| Acidity as acetic acid | ≤ 0.005% by mass | ASTM D1613 |
| Color, Pt-Co | ≤ 5 | ASTM D1209 |
| Hydroquinone inhibitor | 3–10 mg/kg | ASTM D2190-07(2021), batch-certified |
| Acetaldehyde | below polymerisation-sensitive chain-transfer threshold; exact limit on certificate of analysis | in-house headspace GC |
| Non-volatile residue | ≤ 0.005 g/100 mL | ASTM D1353-13 |
Continuous polyvinyl acetate dispersion synthesis with the FC monomer is typically run in a jacketed stirred reactor at solids targets from 55% to 65% by mass, with a redox initiator system operating below 80°C. The controlled aldehyde profile reduces batch-to-batch variation in viscosity development and residual monomer concentration after the finishing stage. On a production line using a wiped-film post-stripping unit, residual vinyl acetate in the finished dispersion is influenced by monomer purity, inhibitor concentration, and stripping vacuum profile; higher acetaldehyde input can produce low-molecular-weight oligomers that survive stripping and contribute to odor and extractables. The FC grade is therefore not a direct guarantee of compliance but an input variable that narrows the variability of downstream migration and organoleptic performance. In a production-scale reactor fitted with a turbine agitator operating at tip speeds between 3 m/s and 5 m/s, the viscosity rise during polymerisation is sensitive to the molecular weight distribution; aldehyde-induced chain transfer lowers K-value and can require compensatory formulation changes to restore adhesive shear resistance. Those formulation changes themselves become part of the food-contact compliance review, so monomer-level control is preferred over post-hoc correction with additional thickeners or crosslinkers.
Across high-pressure EVA copolymerisation lines, reactor pressures above 100 MPa and temperatures from 150°C to 300°C create conditions under which acetic acid derived from VAM hydrolysis can accelerate autoclave wall corrosion and generate metal ions that destabilise the low-density polyethylene backbone. The FC grade applies tighter acidity and water limits, reducing the concentration of acid available for autoclave surface attack and reducing the frequency of emergency reactor shutdowns for wall passivation inspection. In high-pressure configurations with a 40 MPa primary compressor and a high-pressure recycle line, acid levels at the upper end of technical-grade specifications have been associated with surface etching on the intercooler shell after extended campaigns; switching to FC-grade monomer with acidity below the ASTM D1613 endpoint has extended inspection intervals in industrial evaluations. The control of water is similarly relevant because water functions as a polar solvent that shifts the phase equilibrium in the high-pressure reactor and can increase gel content in the finished copolymer. These effects are more pronounced in tubular reactors with limited back-mixing, where local acid accumulation is not rapidly diluted by fresh feed. Downstream, EVA compounds produced from high-acid monomer may show increased gel counts during twin-screw compounding on an L/D 40:1 machine, with melt pressure fluctuation at the screen pack serving as an early indicator of acid-related molecular defects. The FC monomer does not eliminate all high-pressure reactor fouling, but it removes a known acid-catalysed contribution to metal ion release and gel formation.
For polyvinyl alcohol synthesis via alcoholysis of polyvinyl acetate, the aldehyde content of the upstream PVAc controls solution color and ash residue in the final PVOH. In a continuous belt alcoholysis process with sodium hydroxide catalyst, residual acetaldehyde in PVAc can form aldol condensation species that increase yellowness index. The FC monomer contributes a lower precursor aldehyde concentration, but the effect is process-dependent; no direct linear correlation between monomer aldehyde and final PVOH color is expected because reactor temperature, catalyst concentration, and post-hydrolysis washing dominate. Field records from PVAc lines that switched mid-campaign to FC monomer show reduced variability in K-value and lower residual aldehyde in the PVAc intermediate, but published data for this specific configuration is limited. When the PVOH is intended for food-contact film, ash content, color, and residual sodium acetate levels are typically more critical than the original VAM assay; however, low-metal and low-aldehyde monomer quality reduces the number of washing cycles required to reach film-grade limits.
Bulk VAM FC is received in dedicated stainless steel or aluminum storage vessels with nitrogen padded headspace. The hydroquinone inhibitor is deliberately not adjusted to the same high end as some technical grades because excess stabiliser can later appear as an extractable component in non-intentionally added substances screening. Maintaining inhibitor concentration above 3 mg/kg and dissolved oxygen at 6–12 mg/L in the monomer headspace is required to prevent autopolymerisation during long-term storage at ambient temperatures below 30°C. Transfer systems constructed from carbon steel are not specified because trace iron can promote acetaldehyde formation; 316L stainless steel or aluminum transfer piping with a surface finish below Ra 0.8 µm is applied in installations where iron contamination must be avoided. At relative humidity above 60%, monomer transfer lines should be blanketed to avoid water ingress, because water partitions into VAM and raises hydrolytic acidity during storage. Copper alloys are excluded from transfer components because copper ions accelerate aldehyde formation and color development in downstream polymerisation. The inhibitor concentration is verified at receipt and again before reactor feed because hydroquinone consumption is not linear with time; consumption can accelerate if the monomer is held in partially filled tanks with repeated nitrogen cycling. A fixed feed-forward inhibitor correction cannot compensate for variable consumption, so the FC grade is handled under closed-loop storage conditions to maintain stabiliser concentration within the certified band.
| Regulatory reference | Scope | Required demonstration stage |
|---|---|---|
| FDA 21 CFR 175.105 | Adhesives | Finished adhesive after polymerisation and compounding |
| FDA 21 CFR 176.170 | Paper and paperboard coatings in aqueous and fatty food contact | Finished coated substrate |
| FDA 21 CFR 176.180 | Paper and paperboard in dry food contact | Finished coated or uncoated paper/board |
| EU 10/2011 | Plastic materials and articles intended for food contact | Finished monolayer or multilayer plastic article |
| GB 9685-2016 | Permitted additives in food contact materials and articles | Formulated compound or finished article |
At the certification level, differences from standard Wanwei VAM grades are concentrated in impurity control and documentation rather than in fundamental monomer chemistry. The FC designation adds raw-material traceability to monomer produced on dedicated purification campaigns, plus batch-specific certificates showing compliance with residual aldehyde, benzene, and heavy-metal criteria that are not always reported for general-purpose grade. Compared with a finished food-contact polymer such as a PVOH film grade, VAM FC does not carry a direct migration limit, and it cannot be used as a substitute for polymer compliance testing. The monomer-level controls reduce the likelihood of migration test failure, but the final article must still meet the overall migration limit of 10 mg/dm² under EU 10/2011 for plastic materials or the specific migration limits assigned to any residual vinyl acetate monomer, where applicable. The same principle applies to FDA compliance: the monomer is evaluated indirectly through the formulated adhesive, coating, or polymer under the applicable food additive regulation, not as a standalone substance. In installations where the VAM FC grade is polymerised into PVAc for chewing-gum base or direct-contact film, the final polymer must additionally satisfy organoleptic and residual monomer limits because monomer purity alone does not establish finished-article acceptability. The operational boundary is therefore clear: the FC monomer is a controlled precursor that reduces extractable-contributing impurities before synthesis, but it is not a finished food-contact compliance certificate.
