| HS Code | 162033 |
| Chemical Formula | C4H6O2 |
| Cas Number | 108-05-4 |
| Molecular Weight | 86.09 g/mol |
| Appearance | Clear colorless liquid |
| Purity | ≥99.9 wt% |
| Density | 0.932 g/cm³ at 20°C |
| Boiling Point | 72.7°C |
| Melting Point | -93.0°C |
| Flash Point | -8°C (closed cup) |
| Autoignition Temperature | 402°C |
| Vapor Pressure | 152 mmHg at 25°C |
| Solubility In Water | 20 g/L at 20°C |
| Viscosity | 0.43 mPa·s at 20°C |
| Refractive Index | 1.394 at 20°C |
As an accredited Sinopec VAM Standard Premium Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Sinopec VAM Standard Premium Grade is packaged in 200 kg steel drums or bulk ISO tanks for safe transport and storage. |
| Container Loading (20′ FCL) | 20′ FCL loading of Sinopec VAM Standard Premium Grade in secured drums, properly labeled, ventilated, and braced for safe transport. |
| Shipping | Sinopec VAM Standard Premium Grade ships in dedicated ISO tank containers or drums, ensuring purity and safe handling. Proper labeling, ventilation, and temperature control are essential. Strict adherence to hazardous material protocols, including secure stowage and spill prevention, guarantees compliant, reliable delivery to global destinations. |
| Storage | Store in a cool, dry, well-ventilated area away from heat, sparks, and open flames. Keep containers tightly sealed, protected from moisture and sunlight. Maintain inhibitor levels to prevent polymerization; use nitrogen blanketing if applicable. Follow local regulations and use compatible materials, ensuring spill containment and proper labeling. |
| Shelf Life | Shelf life is 12 months when stored in sealed original containers, away from heat, moisture, and ignition sources. |
In furniture-grade polyvinyl acetate emulsion polymerization, the induction period of the first charge is governed less by initiator concentration than by the acetaldehyde and water content of the vinyl acetate monomer stream. Sinopec VAM Standard Premium Grade with ≥99.8% purity, <0.02 wt% water, and <0.005 wt% acetaldehyde reduces the inhibition period in a 65–75°C isothermal semi-batch profile and limits the incidence of high-viscosity microgel specks in the finished wood adhesive. Compliance for furniture-grade products is tested against EN 204:2016 durability classes D1 through D4, with tensile shear measured according to EN 205:2016 and ASTM D905-08. In a representative homopolymer formulation, VAM constitutes 100 parts per 100 parts total monomer; for water-resistant D3 grades, the polymer backbone is adjusted to 80–90 parts VAM with 10–20 parts ethylene or butyl acrylate by weight. The production process involves charging deionized water, a polyvinyl alcohol protective colloid such as 4-88 or 17-88, and a potassium persulfate initiator into a 20,000 L glass-lined reactor fitted with a reflux condenser and half-moon impeller at 35–50 rpm, then feeding VAM over 4–6 h under nitrogen at 70°C; residual monomer is steam-stripped at 80–90°C under reduced pressure to below 0.1 wt% before cooling and pH adjustment to 4.0–5.5. Terminal product types include D2 interior furniture assembly adhesives, D3 edge-banding and veneer-lamination adhesives, and D4 high wet-strength window fillet and door wrap glues, each with Brookfield RVT viscosity typically in the 3,000–18,000 mPa·s range at 25°C using spindle 3 at 20 rpm.
Under production-scale conditions, batch-to-batch viscosity variation arises from residual acetaldehyde in the monomer rather than from the protective colloid level; acetaldehyde values below 0.005 wt% avoid irregular exotherms and permit a 4–6 h feeding window without accumulation of seed particle coagulum. If the pH is allowed to fall below 3.5 during the post-strike phase, coagulum deposits on baffles and thermocouples reduce heat transfer and force early shutdown; therefore no polyvalent salt coagulants or strong acid should be combined with the dispersion before final stabilisation. The reactor is held at 70°C, cooled to 35–40°C after stripping, and filtered through 250 µm mesh to remove microgrit before filling.
The saponification rate of the intermediate polyvinyl acetate is controlled by the methanol ratio, sodium hydroxide catalyst molar feed, and residual water content of the vinyl acetate monomer. Sinopec VAM Standard Premium Grade with water below 0.02 wt% and acetaldehyde below 0.005 wt% reduces chromophore formation during 40–60°C belt or kneader alcoholysis. Compliance for PVOH textile sizing and paper surface-sizing grades is specified by ISO 15023-1:2001, while water-soluble films for unit-dose detergent packaging are qualified against FDA 21 CFR 177.1670 and migration requirements referenced in EU Regulation 10/2011. In terms of formulation addition ratio, VAM is polymerized as 100 parts per 100 parts total monomer in methanol at 20–35 wt% monomer concentration; after ≥99.5% conversion, sodium hydroxide is introduced at 0.2–0.5 mol per mol acetyl group and methanol-to-PVAc mass ratio is maintained at 1.5:1–2.5:1. The downstream process begins with a solution polymerisation in methanol at 60–70°C, followed by continuous saponification in a belt reactor, kneader, or tower with residence time 20–90 min; methyl acetate by-product is removed by distillation, and the wet PVOH is ground and dried to 0.1–0.5 wt% residual moisture in a fluid-bed dryer. Terminal product types include 87–89 mol% hydrolyzed PVOH for textile warp sizing, 92–96 mol% material for paper surface sizing, 98–99 mol% PVOH for water-soluble detergent films and polyvinyl butyral resin precursor, and 80–88 mol% grades used as suspension stabilizers in PVC production.
Operational boundary: residual sodium acetate and methyl acetate in the final PVOH create haze in film grades and must be reduced by multiple methanol washes to <0.5 wt%; saponification above 60°C in high-viscosity kneader processes increases gel particle formation, especially when water content in methanol exceeds 1.5 wt%. A continuous tower process using a 1.5:1 methanol-to-PVAc ratio achieves high-throughput hydrolysis but is not suitable for high-viscosity 98–99 mol% film grades because of limited mass transfer at late-stage saponification.
At the high-pressure autoclave, ethylene and vinyl acetate are co-fed into a continuous stirred tank reactor where the vinyl acetate content in the copolymer determines the crystallinity, polarity, and melt viscosity of the pelletized resin. Sinopec VAM Standard Premium Grade is metered into the feed at 28–33 wt% of the total monomer mass for photovoltaic encapsulant grades, 18–28 wt% for packaging film and extrusion lamination, and 33–40 wt% for hot-melt adhesive and footwear foam grades; polymerization occurs at 1,200–1,800 bar and 180–250°C using an organic peroxide initiator in a high-pressure autoclave process with molecular weight control via propylene or selected chain-transfer agents. Compliance for photovoltaic encapsulant films is tested under IEC 61215-2:2021 damp heat conditions of 85°C and 85% RH for 1,000 h, with melt flow rate determined by ASTM D1238-20 at 190°C under 2.16 kg, density by ASTM D1505-18, and acetyl group degradation monitored after accelerated UV exposure per ASTM G154-16. The downstream process involves underwater pelletizing of the reactor melt, pre-drying to <0.05 wt% moisture before compounding with silane coupling agents and peroxide crosslinkers in a L/D 30:1 co-rotating twin-screw extruder at 180–210°C, then cast film extrusion at 400–600 µm thickness; terminal products include photovoltaic module encapsulant films, low-temperature heat-seal packaging films, hot-melt adhesives, injection-molded footwear foams, and cable compounds.
Photovoltaic encapsulant production is more sensitive to VAM sequence distribution than to average VAM content: insufficient VAM incorporation produces low light transmittance and poor silane adhesion, while excessive VAM raises moisture uptake and reduces volume resistivity. At the lamination line, the EVA sheet is pre-laminated at 140–160°C under 0.1–0.3 MPa vacuum; gel content after curing is measured by solvent extraction per ASTM D2765-16 and is maintained at 70–90%. Melt processing above 230°C should be avoided because deacetylation releases acetic acid, causes yellowing, and reduces gel content of the cured encapsulant.
| VAM content | MFR ASTM D1238-20 | Density ASTM D1505-18 | Primary terminal product |
|---|---|---|---|
| 18–28 wt% | 2–15 g/10 min | 0.930–0.950 g/cm³ | Extrusion coatings, packaging sealants |
| 28–33 wt% | 15–45 g/10 min | 0.950–0.960 g/cm³ | Photovoltaic encapsulant film |
| 33–40 wt% | 150–400 g/10 min | 0.960–0.980 g/cm³ | Hot-melt adhesives, footwear foam |
When ethylene is introduced at 10–50 bar into a vinyl acetate emulsion feed, the resulting vinyl acetate–ethylene copolymer dispersion lowers minimum film-forming temperature and permits architectural coatings with reduced coalescent solvent demand. Sinopec VAM Standard Premium Grade is charged at 70–95 parts by weight with 5–30 parts ethylene in the polymerisation recipe; the emulsion is produced in a medium-pressure stirred reactor at 50–80°C with a redox initiator such as sodium persulfate/sodium metabisulfite and stabilized by polyvinyl alcohol or anionic/nonionic surfactant packages to a final particle size of 80–250 nm, solids of 50–60 wt%, and pH 4.0–5.0. Compliance for architectural paint use includes EU Directive 2004/42/EC Phase II VOC limit of 30 g/L for interior matte wall paint, ASTM D2369-20 for VOC content, ISO 11890-2:2020 for VOC determination, and GB/T 9756-2018 for synthetic resin emulsion interior wall coatings. The downstream formulation for flat interior paint uses 20–35 wt% VAE latex in total wet paint, 0–2 wt% coalescent, cellulosic or associative thickener, and titanium dioxide pigment; for carpet backing and paper coating the dispersion is applied directly at 15–40 wt% latex solids add-on in a blade coater or air knife coater. Terminal product types include low-VOC interior matt and silk paints, exterior masonry primers, carpet backing adhesives, paper coatings, and nonwoven binder applications. Operational boundaries include pH below 3.0 or above 7.0 causing destabilization and filter plugging; because ethylene reduces the glass transition to near 0°C, the frozen-thaw stability of the latex is evaluated by cyclic storage at -5°C to ambient temperature.
On production-scale carpet backing lines, foaming surfactants and calcium carbonate filler alter the shear viscosity; the VAE latex must exhibit Brookfield viscosity of 2,000–8,000 mPa·s at 20 rpm to maintain stable web penetration without excessive splash. For paper coating, the unit is run in a blade coater with a coat weight of 4–12 g/m² dry, and the dispersion rheology is adjusted with alkali-swellable thickeners to a Hercules high-shear viscosity of 30–100 mPa·s to avoid streaking at 1,000 m/min.
Cementitious tile adhesive producers blending redispersible polymer powder into thin-set mortars depend on the VAM-derived ethylene comonomer to provide flexibility and adhesion after water immersion. Sinopec VAM Standard Premium Grade enters the supply chain through vinyl acetate–ethylene or polyvinyl acetate emulsions containing 70–95 wt% VAM, which are spray-dried at inlet 140–180°C and outlet 55–85°C with 8–15 wt% kaolin or fine silica anti-caking agent; the resulting redispersible polymer powder has a D50 particle size of 60–100 µm and redisperses to 50–250 µm particle size emulsion in water. In C2TE and C2FT mortar formulations the RDP dosage is 1.5–6.0 wt% of total dry mix for ceramic tile adhesives, 2.0–8.0 wt% for self-leveling underlayments, and 0.5–3.0 wt% for repair mortars; cellulose ether content is maintained at 0.1–0.4 wt% to adjust open time. Compliance is established under ISO 13007-2:2013 and EN 12004-1:2017 for C1 and C2 classifications, deformability classes S1/S2 per EN 12002-1:2008, and tensile adhesion strength after water immersion and heat ageing per EN 1348:2007. Downstream dry-mix production uses twin-ribbon gravity blenders at 15–30 rpm to avoid polymer powder degradation, blending Portland cement, graded sand, RDP, cellulose ether, and calcium formate for C2FT fast-setting products; the powder is then packaged into moisture-barrier bags to keep residual moisture below 0.5 wt%. Terminal product types include C2TE extended-open-time tile adhesives, C2FT fast-setting tile adhesives, self-leveling floor screeds, external thermal insulation composite system basecoats, and repair mortars. Operational boundary: RDP should never be added to dry-mix after cement because that creates localized high-shear heat and reduces redispersibility; storage at relative humidity above 70% or temperature above 30°C causes caking.
Production-scale spray drying of the source emulsion requires atomizer wheel speed of 10,000–15,000 rpm and a feed solids ratio of 35–45 wt%; below 35 wt% solids the dryer throughput drops and residual moisture rises, while above 45 wt% solids the atomizer nozzle clogging risk increases. After spray drying, the powder is cooled to below 35°C before bagging because warm product tends to fuse under warehouse stack pressure.
Vinyl chloride–vinyl acetate copolymer binder synthesis for gravure inks and maintenance coatings uses VAM at 5–20 wt% of the polymer mass to lower solution viscosity and improve adhesion to metalized films and aluminum surfaces. Sinopec VAM Standard Premium Grade is loaded into a batch solution polymerisation reactor in methyl ethyl ketone or methyl ethyl ketone/toluene at 60–75°C with azobisisobutyronitrile initiator at 0.2–1.0 wt% relative to monomer; the resulting resin is steam-precipitated or solvent-stripped below 50°C to avoid dehydrochlorination, then dried to <0.3 wt% residual volatiles. For high-solids gravure ink formulations, the VAM content is maintained at 10–15 wt% to balance ketone solubility and pigment wetting, while vinyl floor tile binders use 5–10 wt% VAM and maintenance coatings use 15–20 wt% VAM with maleic acid or hydroxyalkyl groups for pigment wetting. Compliance for printing ink flow is measured by ASTM D1200-10 Ford viscosity cup, solvent resistance of cured coating film by ASTM D5402-19 methyl ethyl ketone double rubs, and viscosity stability by ISO 2555:2018 Brookfield rotation; can coatings may be qualified under FDA 21 CFR 175.300 for resinous and polymeric coatings. Terminal product types include flexographic and gravure packaging inks, industrial maintenance topcoats, can coatings, vinyl floor tile binders, and acoustical tile binders. Operational boundary: the resin should not be melt-compounded above 150–170°C on a two-roll mill without an organotin or calcium-zinc thermal stabilizer, otherwise hydrogen chloride evolution accelerates viscosity drop and discoloration.
Production-scale dispersion of these solution resins into ink bases uses a Cowles high-shear dissolver at 15–25 m/s tip speed; post-milling is completed in a horizontal bead mill at 40–50°C because higher temperatures increase solvent evaporation and shift the resin solubility parameter.
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Sinopec VAM Standard Premium Grade is polymerisation-grade vinyl acetate monomer, CAS 108-05-4, molecular formula C4H6O2, molar mass 86.09 g/mol, supplied as a clear liquid with a normal boiling point of 72.7 °C at 101.3 kPa and closed-cup flash point -8 °C. The grade designation operates as the commercial model identifier; no separate numerical model code appears in the standard safety data sheet, while batch traceability is maintained through lot number, production site, and certificate of analysis. The product is used where radical polymerisation kinetics require a narrow impurity envelope and a controlled hydroquinone inhibitor concentration.
Batch-quality variation in commodity vinyl acetate monomer is most visible during the induction phase of emulsion polymerisation. In a 25 m³ 316L stainless steel stirred-tank reactor operating between 60 °C and 80 °C, the premium grade reduces induction-period drift relative to uncontrolled monomer deliveries. Formulators using commodity VAM above the premium acetaldehyde limit commonly compensate with additional persulfate initiator or buffer; the observed consequence is increased coagulum deposition on flat-blade turbine and baffle surfaces, with reduced heat-transfer coefficients over multi-batch campaigns.
The commercial distinction centres on three independent variables: hydroquinone inhibitor loading, aldehyde and acid speciation, and water content. The standard premium specification keeps hydroquinone between 5 and 15 mg/kg, whereas common commodity polymerisation grades may be released between 3 and 20 mg/kg and low-inhibitor grades are controlled below 5 mg/kg. A low-inhibitor package is not automatically superior; it is selected for radiation-cured or initiator-free systems where residual quinone species are unacceptable, but it increases storage sensitivity and peroxide formation risk if oxygen transfer is interrupted. The premium package is therefore positioned for applications where the polymerisation line needs a predictable radical-scavenging load and the storage interval is longer than 30 days.
For producers that switch from commodity VAM to the standard premium grade, the main recipe adjustment is removal of the safety initiator and buffer allowances previously required for wide impurity variation. This change is not universal; end-product qualification under ASTM D638-14 tensile testing or ISO 1133-1:2022 melt flow testing remains necessary because the optimum initiator level depends on reactor geometry, agitation power per unit volume, and heat removal capacity.
| Attribute | Standard Premium Grade | Commodity polymerisation grade | Low-inhibitor grade |
|---|---|---|---|
| Hydroquinone inhibitor | 5–15 mg/kg | 3–20 mg/kg | ≤ 5 mg/kg |
| Acidity as acetic acid | ≤ 50 mg/kg | ≤ 100 mg/kg | ≤ 50 mg/kg |
| Water | ≤ 300 mg/kg | ≤ 500 mg/kg | ≤ 200 mg/kg |
| Acetaldehyde | ≤ 30 mg/kg | ≤ 100 mg/kg | ≤ 20 mg/kg |
| Primary use | High-consistency PVA and VAE emulsions | General-purpose PVAc adhesives | Long-storage or high-radiation cure systems |
The following representative release limits are typical for polymerisation-grade material and are confirmed on each certificate of analysis. Test methods listed are used in routine release testing; other methods may be acceptable under supply agreements.
| Property | Test method | Limit |
|---|---|---|
| Vinyl acetate purity | GC-FID, internal method | ≥ 99.9 % by mass |
| Water | ASTM E203 | ≤ 300 mg/kg |
| Acidity as acetic acid | ASTM D1613 | ≤ 50 mg/kg |
| Hydroquinone inhibitor | UV-visible spectrophotometric method | 5–15 mg/kg |
| Acetaldehyde | GC-FID headspace | ≤ 30 mg/kg |
| Colour, Pt-Co | ASTM D1209 | ≤ 5 |
| Distillation range | ASTM D1078 | 71.8–73.0 °C |
The limits in the table should be read as interlocking control points rather than independent properties. Acetic acid and water interact in storage through slow esterification and hydrolysis equilibria, and acetaldehyde can form from oxidation of the vinyl group if oxygen and trace metals are present. Premium-grade release testing therefore monitors the entire impurity envelope via a single GC-FID method with multiple calibrated detectors, and the certificate of analysis reports the actual batch values, not merely pass/fail results.
The distillation range is not only a purity indicator but also a process-control variable in continuous feed systems. A wide-boiling fraction above 73.0 °C can contain dimeric species such as vinyl acetate dimer or heavier acetates; when concentrated in recycle loops, these species contribute to fouling in feed preheaters. The premium specification narrows the upper distillation endpoint relative to commodity grades, which reduces the rate of preheater fouling in continuous PVA plants.
Acetaldehyde acts as a chain-transfer agent in free-radical vinyl acetate polymerisation. Even small increases in aldehyde concentration, from 30 mg/kg to 100 mg/kg, can depress number-average molecular weight and shift the molecular weight distribution toward shorter chains. In high-solids vinyl acetate-ethylene emulsions, this chain-transfer effect lowers tensile modulus and increases surface tack unless the aldehyde burden is controlled below the premium specification.
Acetic acid contributes to aqueous-phase pH depression. In a typical semi-continuous emulsion recipe with a total monomer feed of 100 parts by mass, an acidity level of 100 mg/kg adds enough acid to lower the aqueous-phase pH by several tenths of a unit if no buffer adjustment is made. With persulfate thermal initiation, pH values below 4.0 accelerate initiator decomposition and generate excess sulfate radicals early in the feed cycle, leading to rapid nucleation and higher coagulum. Plant data from 316L stainless steel reactors operating at 70 °C indicate that fouling rates increase when the unneutralised monomer acidity exceeds the premium limit of 50 mg/kg.
Water in VAM participates in alcoholysis and transesterification reactions. In polyvinyl alcohol production, water entering the methanolysis unit consumes alkali catalyst and increases sodium acetate formation. A water level above 300 mg/kg may shift the degree of hydrolysis unless catalyst feed is adjusted, which is outside the preferred control window for many textile-grade PVA specifications. Published data for the full range of commercial reactor geometries is limited, but the direction of these effects is consistent with standard emulsion polymerisation literature and with manufacturer guidance on buffer addition.
Hydroquinone inhibition in VAM is oxygen-dependent, so storage must retain air rather than inert nitrogen. The vapour space should remain in contact with atmospheric air, approximately 20.9 % oxygen by volume; inert-gas blanketing must be avoided because it deactivates the inhibitor and allows peroxide formation. Tanks should be of carbon steel or stainless steel; copper, brass, and copper-bearing alloys are incompatible because soluble copper redox-cycles the inhibitor and can initiate low-temperature polymerisation. Heat-exchanger bundles with copper-bearing tubes must not be used in VAM service.
At temperatures above 30 °C, dimer formation and inhibitor consumption accelerate. If the product is held for more than 60 days, the hydroquinone content should be re-measured by the UV-visible method and the material should be re-inhibited if the concentration falls below 5 mg/kg. Transfer lines and metering pumps should be 316L stainless steel or carbon steel with PTFE and EPDM elastomer seals. Ethylene-propylene-diene monomer seals may be used, but butyl rubber and nitrile rubber swell in VAM service and should be excluded. The material is a flammable liquid; closed-cup flash point is -8 °C, and vapours are heavier than air. Bonding and grounding of all transfer equipment is mandatory.
In continuous polyvinyl alcohol manufacture, Sinopec VAM Standard Premium Grade is fed to polymerisation trains followed by methanolysis. The low water burden reduces alkali catalyst consumption and sodium acetate by-product; the controlled aldehyde content narrows the distribution of degree of polymerisation around the target value for sizing and film grades. In pressure-rated stirred autoclaves for vinyl acetate-ethylene emulsions, the monomer is metered at ethylene partial pressures from 20 to 80 bar. The premium inhibitor package allows a stable initiator feed without repeated vacuum-argon purges, while the low acetaldehyde concentration reduces short-chain branching and preserves film clarity in low-odour interior paints.
In polyvinyl acetate wood adhesives, the monomer is typically reacted in a semi-batch process with partially hydrolysed polyvinyl alcohol as protective colloid. The exotherm is controlled by monomer feed rate and jacket cooling at 60–70 °C. With the premium grade, the onset temperature of rapid polymerisation occurs within a narrower time window, allowing automatic feed sequencing to be used without overshoot above 80 °C. Uncontrolled exotherm due to inhibitor variability is a known cause of reactor gelation in 10 m³ and larger reactors; the standard premium inhibitor concentration reduces this risk but does not eliminate the requirement for redundant temperature interlocks.
In low-odour interior paints, the premium grade is used in vinyl acetate-ethylene binders where residual acetaldehyde in commodity monomer is linked to aldehyde off-odour after film formation. Headspace acetaldehyde of the final paint can be measured by gas chromatography after accelerated storage at 40 °C for 14 days; premium-grade monomer reduces that value relative to commodity VAM, but the final result depends on coalescent selection and preservative chemistry. For construction adhesives and redispersible polymer powders, the premium grade is used only after compatibility testing with protective colloids. Polyvinyl alcohol stabilised emulsions can be sensitive to residual acetic acid; neutralisation with sodium acetate or ammonium hydroxide may be required before spray drying. The material is not a food-contact article and must be evaluated in the finished adhesive under 21 CFR 175.105 or the equivalent national provision for indirect food contact.
