| HS Code | 850914 |
| Product | Celanese Vinyl Acetate HQ 25-30 |
| Chemicalname | Vinyl acetate monomer |
| Chemicalformula | C4H6O2 |
| Casnumber | 108-05-4 |
| Appearance | Clear colorless liquid |
| Purity | 99.9% minimum |
| Inhibitorcontent | Hydroquinone 25-30 ppm |
| Molecularweight | 86.09 g/mol |
| Boilingpoint | 72.7 °C |
| Meltingpoint | -93 °C |
| Flashpoint | -8 °C (closed cup) |
| Specificgravity | 0.932 at 20/20 °C |
| Vapordensity | 3.0 (air=1) |
| Vaporpressure | 89 mmHg at 20 °C |
| Solubilityinwater | 2% by weight at 20 °C |
| Autoignitiontemperature | 427 °C |
| Refractiveindex | 1.3953 at 20 °C |
As an accredited Celanese Vinyl Acetate HQ 25-30 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Celanese Vinyl Acetate HQ 25-30 is packaged in 190 kg steel drums, bulk ISO tanks, or tank trucks for large deliveries. |
| Container Loading (20′ FCL) | 20' FCL loading of Celanese Vinyl Acetate HQ 25-30: drums/pails secured, ventilated, segregated, labeled, with proper hazardous material handling. |
| Shipping | Ship Celanese Vinyl Acetate HQ 25-30 as a flammable, stabilized liquid in approved drums or isotanks. Keep away from heat, sparks, and polymerization triggers. Use dedicated, grounded equipment, and follow UN 1301 regulations for vinyl acetate. Ensure proper labeling, ventilation, and secondary containment during transport. |
| Storage | Store Celanese Vinyl Acetate HQ 25-30 in a cool, dry, well-ventilated area away from heat, sparks, open flames, and direct sunlight. Keep containers tightly closed and upright, with adequate air space to preserve inhibitor effectiveness and prevent polymerization. Avoid contamination by water or reactive materials. Follow manufacturer’s temperature guidelines and ensure proper grounding during dispensing. |
| Shelf Life | Shelf life is typically 6 months when stored below 25°C, kept dry, and protected from light and air. |
Celanese Vinyl Acetate HQ 25-30 is a hydroquinone-stabilized vinyl acetate monomer with an inhibitor concentration specified at 25–30 ppm. The product aligns with ASTM D2190-07(2021) for vinyl acetate monomer, and the hydroquinone concentration is determined by ASTM D2193-97(2014). Typical assay is 99.8 % minimum by gas chromatography, acidity as acetic acid is 0.01 % maximum, water is 0.05 % maximum, and colour is 5 Pt-Co maximum. Hydroquinone functions as an aerobic inhibitor, so storage tanks are maintained at 10–30 °C with an oxygen-containing vapour space rather than a nitrogen blanket; dissolved oxygen below 5 ppm can extend the induction period unpredictably. Stainless steel or aluminium equipment is specified, while copper, brass, and Monel contact surfaces are incompatible because they accelerate colour body formation and risk localised bulk polymerisation. The monomer is normally delivered with inhibitor in place; downstream polymerisation recipes compensate by initiator adjustment rather than removal, except in optical-grade polyvinyl alcohol and low-colour ethylene-vinyl alcohol routes where distillation or inhibitor extraction is required before use.
Conventional wood and paper converting adhesives built around polyvinyl acetate homopolymer consume Vinyl Acetate HQ 25-30 as the primary monomer. The formulation addition ratio for a D3 wood adhesive is 100 parts VAM per 100 parts total monomer when no comonomer is used, and 85–95 parts VAM per 100 parts total monomer when butyl acrylate or 2-ethylhexyl acrylate is included for plastic-film adhesion; total VAM concentration in the batch is 45–55 wt%. In a 10,000 L jacketed glass-lined reactor with a pitched-blade impeller at 80–120 rpm, the aqueous phase is prepared with 3–6 wt% partially hydrolysed polyvinyl alcohol (86.5–89.0 mol%) and 0.1–0.3 wt% hydroxyethyl cellulose on total monomer, then heated to 65–70 °C. A seed precharge of 5–8 wt% of the total VAM charge is added under agitation, followed by a delayed monomer feed over 3.5–4.5 h at 70–75 °C. The initiator system is ammonium persulfate at 0.35–0.50 wt% on total monomer, fed as a 5 wt% aqueous solution; the hydroquinone inhibitor from the monomer consumes a measurable radical inventory and produces a 15–30 min inhibition interval, so the initial initiator shot is increased by 0.05 wt% relative to uninhibited monomer. Residual vinyl acetate monomer is reduced to below 0.2 % by a post-catalysis redox pair of tert-butyl hydroperoxide and sodium metabisulfite at 0.05–0.10 wt% each. The finished dispersion is adjusted to pH 4.0–5.5, solids 50–55 %, and viscosity 2,000–5,000 mPa·s at 23 °C. Compliance for North American food packaging adhesive applications is covered by FDA 21 CFR 175.105; for European woodworking adhesives, the dispersion is tested against EN 204:2016 classes D3 and D4, with tensile shear strength measured under ASTM D905-08(2021) after conditioning at 23 °C and 50 % RH. Terminal product types include white wood glues, paper tube winding adhesives, bookbinding adhesives, envelope closure adhesives, and laminating adhesives for printed paperboard.
In pressurised vinyl acetate-ethylene dispersion lines, Vinyl Acetate HQ 25-30 is metered as the principal monomer at a formulation addition ratio of 70–85 wt% of total organic monomer, with ethylene fed at 15–30 wt% and a vinyl silane, acrylamide, or sodium vinyl sulfonate functional stabiliser at 0.5–1.5 wt%. The reactor is a stainless steel autoclave rated to 50 bar, with dual axial turbine agitation at 90–150 rpm and an ethylene mass-flow controller maintaining a partial pressure plateau of 20–50 bar. Aqueous phase composition contains 3–6 wt% partially hydrolysed PVOH and 0.5–1.2 wt% nonylphenol-free anionic surfactant on total VAM. The polymerisation temperature is maintained at 55–65 °C using redox initiation with sodium persulfate and sodium formaldehyde sulfoxylate at 0.25–0.40 wt% total on monomer mass. The 25–30 ppm hydroquinone load in the monomer creates an induction period of 10–25 min that varies with iron content and pH drift; production lines compensate by precharging 5–10 wt% of the VAM feed before ethylene pressure reaches the set point and by splitting the reducing agent feed so that the redox couple is not exhausted before the inhibitor is consumed. The dispersion is stripped after polymerisation at 50–60 °C under 100–200 mbar vacuum until residual vinyl acetate monomer is below 0.1 % as measured by gas chromatography. Final properties are set at solids 55–60 %, pH 4.0–5.5, viscosity 500–2,000 mPa·s at 23 °C, and minimum film formation temperature 0–10 °C. The VAE dispersion qualifies for construction adhesive formulations under EN 12004:2017 class C2TE, where it is added to cement at 2.5–4.0 wt% dry polymer; for decorative interior coatings, VOC emissions are evaluated by GB 18582-2020, and for European indoor installation materials the dispersion is assessed under EMICODE EC1 Plus. Terminal product types include low-odour interior wall paints, cementitious tile adhesives, self-leveling floor screeds, waterproofing slurries, and external thermal insulation composite system base coats.
Spray drying of a VAM-rich VAE dispersion into redispersible polymer powder uses a base dispersion formulated at 75–80 wt% VAM on total monomer, with ethylene at 20–25 wt% and PVOH protective colloid at 5–15 wt% on polymer solids. The liquid feed is preheated to 25–35 °C and atomised in a rotary atomizer at 10,000–12,000 rpm, producing a droplet D50 of 40–60 μm. Dryer inlet temperature is controlled at 140–160 °C, outlet temperature at 55–70 °C, because the polymer minimum film formation temperature is below 10 °C and particle sintering will otherwise create insoluble grit. The powder is post-blended with 5–15 wt% kaolin or calcium carbonate anti-blocking agent and 0.1–0.5 wt% hydrophobic silica to maintain free flow at powder bulk density 400–600 g/L. The spray-dried powder is redispersible in water and is used in dry-mix mortars at a dosage of 2.0–4.0 wt% of total dry mortar mass. Film formation after cement hydration improves adhesion, flexural strength, and open time; the powder-modified adhesive is classified under EN 12004:2017 C1 or C2, with characteristic requirements of ISO 13007-2:2013. For factory-made renders and repair mortars, the powder is used in formulations under EN 998-1:2016 and EN 13813. Terminal product types include cement-based tile adhesives, self-leveling floor screeds, patching mortars, external wall render, and gypsum joint fillers. The residual hydroquinone-related chromophores in the dried polymer are minimised by maintaining an iron-free latex loop and using ethylenediaminetetraacetic acid at 0.02–0.05 wt% in the base dispersion.
An indirect-monomer conversion route to polyvinyl alcohol consumes Vinyl Acetate HQ 25-30 as the sole vinyl monomer. The formulation addition ratio is defined by a methanol-to-VAM mass feed ratio of 2.0:1 to 2.8:1 in a continuously stirred jacketed polymerisation train operating at 50–65 °C. Azo initiator is dosed at 0.01–0.05 wt% on VAM. Because the monomer carries 25–30 ppm hydroquinone, the induction threshold fluctuates when the initiator pre-mix age exceeds 8 h, so fresh initiator feed and dissolved oxygen monitoring at 5–10 ppm in the monomer stream are used to avoid high-molecular-weight drift. The polymerisation is intentionally stopped at 60–70 % conversion in a vacuum distillation column where unreacted vinyl acetate is recovered as distillate at 72.7 °C and recycled. The PVAc solution is then saponified at 30–45 °C with sodium hydroxide in methanol at 0.02–0.05 mol NaOH per mol acetyl group; belt saponification or open-kneader units gelatinise the PVOH before a methanol wash reduces sodium acetate to 1.0–2.0 wt%. Drying at 90–110 °C lowers moisture below 5 %, and grinding yields a powder with particle size D50 200–500 μm. Partially hydrolysed grades at 86.5–89.0 mol% serve textile warp sizing and paper surface sizing; fully hydrolysed grades at 98.0–99.9 mol% are used for water-soluble films and pharmaceutical tablet coating binders. The product is controlled under the USP Polyvinyl Alcohol monograph, Ph. Eur. 2102, FDA 21 CFR 177.1670 for polyvinyl alcohol film in food contact, and EU 10/2011 for plastics intended for food contact. Terminal product types include textile sizing agents, paper coating binders, detergent pod films, pharmaceutical tablet coatings, and polarising film raw stock where low sodium acetate and low yellowness are critical.
For ethylene-vinyl acetate copolymer production, Vinyl Acetate HQ 25-30 is co-fed with ethylene into a high-pressure autoclave or tubular reactor with operating pressure 1,500–2,200 bar and temperature 160–220 °C. The downstream EVA formulation addition ratio for photovoltaic encapsulant is 28–33 wt% vinyl acetate content in the final resin; hot-melt adhesive grades use 18–28 wt%. Because VAM monomer conversion is incomplete in high-pressure free radical polymerisation, the VAM mass fraction in the fresh feed is trimmed to 20–25 wt% depending on reactor length-to-diameter ratio, agitator shear, and polymer grade. Propionaldehyde telogen at 0.02–0.10 wt% on monomer controls melt flow rate to 5–35 g/10 min at 190 °C and 2.16 kg load according to ASTM D1238. After high-pressure separation and underwater strand pelletising, pellets are dry-blended with 0.5–1.5 wt% tert-butyl peroxy-2-ethylhexanoate or tert-butyl peroxybenzoate, 0.05–0.30 wt% vinyl silane adhesion promoter, and UV stabiliser masterbatch. The encapsulant sheet is cast-calendered at 70–90 °C to a thickness of 400–600 μm. On production-scale sheet lines, hydroquinone-derived colour bodies and EVA gel particles above 2 % defect threshold are observed as filter pressure rise and reduced optical transmission; gel fraction is measured by xylene dissolution followed by 65 μm screen retention, and yellowness index is kept below 1.5 on the film. Compliance for photovoltaic module encapsulation includes IEC 61215-1:2021, IEC 61730, and UL 746C; food-contact EVA is evaluated under FDA 21 CFR 177.1350. Terminal product types include photovoltaic cell encapsulant sheets, wire and cable jacketing compounds, hot-melt adhesive sticks, and compounding base resins.
The manufacture of ethylene-vinyl alcohol begins with a high-vinyl-acetate EVA intermediate in which vinyl acetate repeat units derived from Vinyl Acetate HQ 25-30 account for 75–85 wt% of the precursor polymer. The vinyl acetate content is deliberately high because the final EVOH ethylene mole fraction must fall between 24 mol% and 48 mol%, with barrier film extrusion grades most commonly at 27–44 mol% ethylene. Precursor polymerisation is carried out in a solution loop reactor at 30–60 bar and 50–80 °C with methanol as solvent; the advantage of this route is that the 25–30 ppm hydroquinone inhibitor in the VAM feed is diluted by methanol and partially partitioned into the recovered monomer stream, reducing its interference with the azo initiator. Transesterification is then performed in a twin-screw or kneader reactor at 40–60 °C with sodium methoxide catalyst at 0.01–0.03 mol per mol acetyl group; methyl acetate and methanol are recovered by azeotropic distillation and returned to the process. Residual acetate below 0.5 wt% is required to maintain haze-free barrier film and low water sensitivity. The EVOH resin is coextruded with polyolefins at melt temperatures 210–230 °C; oxygen transmission rate is measured by ASTM D3985-17 at 23 °C and 0 % RH, with barrier grades requiring OTR below 0.5 cm³·m⁻²·day⁻¹·atm⁻¹ at 15 μm layer thickness. Compliance for food contact is governed by EU 10/2011 and by the designation and specification framework of ISO 14663-1:2006 for EVOH extrusion and moulding materials. Terminal product types include coextruded food packaging films, medical blister lamination, automotive fuel tank liner multilayer sheets, and agrochemical barrier bottles.
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Celanese Vinyl Acetate HQ 25-30 is a vinyl acetate monomer grade inhibited with hydroquinone at a nominal loading of 25–30 mg/kg. The substance, registered under CAS 108-05-4, has the formula C4H6O2, a molecular weight of 86.09 g/mol, a normal boiling point of 72.7 °C at 101.3 kPa, and a closed-cup flash point of −8 °C determined by ASTM D56. The hydroquinone inhibitor concentration is the grade-defining variable, because vinyl acetate is susceptible to radical self-polymerisation when exposed to heat, light, or peroxide impurities. The 25–30 mg/kg inhibitor band is intended for extended bulk storage and multi-modal transport where a lower-inhibitor grade would risk viscosity rise or exothermic polymerisation in tank farms. Downstream use covers free-radical polymerisation to polyvinyl acetate homopolymers, vinyl acetate-ethylene copolymers, vinyl acetate-acrylic dispersions, and subsequent alcoholysis to polyvinyl alcohol.
In a thermally initiated emulsion polymerisation at 70–85 °C, hydroquinone functions as a radical scavenger that consumes primary radicals and short-propagating-chain radicals before stable latex nucleation occurs. The induction period is not determined solely by the inhibitor concentration; it scales with the radical flux delivered by the initiator system, which for potassium persulfate depends on temperature, pH, buffer capacity, and the presence of transition-metal impurities. A shift from the lower end to the upper end of the 25–30 mg/kg band can require an increase in the initial persulfate shot or a delay in monomer feed until the exotherm associated with nucleation is observed on the reactor trending system. Isothermal reaction calorimetry according to ASTM E2160 or differential scanning calorimetry using sealed cells can be used to compare induction time across batches. In production-scale stirred reactors of 10–20 m³ working volume with turbine agitation, batch-to-batch variance in inhibitor level is most visible in the time from initiator addition to the first 2–3 K exotherm and in the residual monomer profile measured by gas chromatography. Lower-temperature redox systems, such as tert-butyl hydroperoxide with sodium formaldehyde sulfoxylate at 50–60 °C, are more sensitive to this inhibitor band than thermal persulfate systems because the radical flux is smaller; a formulation that is robust at 70 °C may show an extended induction period at 55 °C unless the reducing agent charge is compensated.
The 25–30 mg/kg hydroquinone concentration is not a permanent stabiliser; it is consumed by oxygen-centred radicals, dissolved oxygen, and adventitious peroxides. Storage vessels should be kept below 30 °C and protected from direct sunlight to slow quinone formation and inhibitor consumption. A nitrogen headspace at 5–10 kPa gauge or equivalent inerting is used in dedicated monomer terminals to lower the oxygen partial pressure; air ingress through pressure-vacuum vents can measurably shorten the useful storage interval. Iron and copper alloys are avoided in transfer equipment because soluble metal ions catalyse peroxide decomposition and can initiate polymerisation even when the hydroquinone concentration is within specification. Before use, a retained sample can be re-analysed by ASTM D2193 to confirm that the inhibitor has not fallen below the specified lower limit. If the measured inhibitor concentration falls below 25 mg/kg or if the sample develops a visible yellow-brown colour, the batch should not be used for long-chain polymer production without re-inhibition or immediate processing. The colour change from hydroquinone to quinone degradation products can be tracked by Pt-Co colour measurements per ASTM D1209.
Typical quality parameters reported on a certificate of analysis for this monomer grade are summarised in the following table; actual lot-specific values are determined by the methods listed and should not be considered standalone specification limits without the manufacturer’s lot certificate.
| Parameter | Nominal specification | Test method |
|---|---|---|
| Vinyl acetate purity | 99.9 wt% min | ASTM D3447 |
| Water | 0.05 wt% max | ASTM D1364 |
| Acidity as acetic acid | 0.005 wt% max | ASTM D1613 |
| Colour | 5 Pt-Co max | ASTM D1209 |
| Hydroquinone | 25–30 mg/kg | ASTM D2193 |
| Distillation range | 71.8–73.0 °C at 101.3 kPa | ASTM D1078 |
Replacing a 3–5 mg/kg hydroquinone-inhibited vinyl acetate with the 25–30 mg/kg grade without adjusting radical generation produces a longer induction period and can shift the monomer sequence distribution in the early oligomer fraction. In a pressurised vinyl acetate-acrylic copolymer reactor, the delay before nucleation increases the residence time of monomer in the aqueous phase and can alter the incorporation ratio of water-soluble comonomers such as acrylic acid; that ratio is controlled by fed-batch monomer flows rather than by equilibrium partitioning alone. Operators may compensate by increasing the initial persulfate addition by an amount determined from calorimetric induction time, not by a fixed recipe constant. The hydroquinone residue also contributes phenolic and quinoid species to the latex serum after polymerisation; this can raise the yellowness index of dried films measured under ASTM D1925 or ISO 14782 if the latex is not neutralised or post-stabilised. Adhesive performance after ageing should be verified with peel and shear tests such as ASTM D1876 and ASTM D3654, because residual inhibitor fragments can influence surface adhesion and tack development. For pressure-sensitive adhesive formulations, the influence is greater in low-gel, high-molecular-weight polymers than in highly crosslinked or high-gel latexes.
In hot-climate terminal operations where ambient tank temperatures exceed 25 °C for part of the year, vinyl acetate-ethylene emulsions for architectural coatings and adhesives are polymerised at 80–90 °C and 10–40 bar ethylene partial pressure in stirred stainless-steel autoclaves. The inhibitor level of 25–30 mg/kg is consumed during the initial batch stage, and polymer chain growth then proceeds under control of the monomer feed profile and protective colloid such as partially hydrolysed polyvinyl alcohol or hydroxyethyl cellulose. In this process, the main operational distinction of the HQ 25–30 grade is not final film tensile strength but initial reaction latency; specifiers choose it when the same bulk inventory must serve multiple downstream reactor types or when the monomer is stored in hot-climate terminals. Published viscosity growth data for this specific Celanese grade under long-term storage is limited; terminal operators therefore rely on periodic inhibitor titration and boiling-point checks rather than on fixed shelf-life extrapolation.
Vinyl acetate purity and trace carbonyl content are more critical for polyvinyl alcohol and ethylene-vinyl alcohol producers than for many emulsion applications. Acetaldehyde, vinyl acetate dimer, and acetic acid act as chain-transfer or hydrolysis-resistant impurities that lower the degree of polymerisation or introduce colour. The acid specification of 0.005 wt% maximum as acetic acid in ASTM D1613 is therefore monitored in polyvinyl alcohol grade selection, because residual acid carries into the alcoholysis step and can shift the saponification mass balance. The low water specification of 0.05 wt% maximum by ASTM D1364 reduces the probability of premature ester hydrolysis in storage and avoids water inhibition of organometallic catalysts in certain copolymer systems. For polyvinyl alcohol, the resulting 4% aqueous solution viscosity is typically measured using a Brookfield or Höppler viscometer under DIN 53015 or JIS K6726 to confirm that the inhibited monomer grade does not introduce measurable chain-transfer drift. Ethylene-vinyl alcohol copolymer producers impose additional limits on aldehydes and unsaturated impurities, because these species co-polymerise and degrade oxygen barrier performance; the hydroquinone inhibitor itself is removed or consumed before high-pressure polymerisation in those processes.
Transport and regulatory classification of Celanese Vinyl Acetate HQ 25-30 follows the same framework as other vinyl acetate monomer grades; the HQ concentration does not alter the hazard classification but changes storage and polymerisation latency. The material is identified by CAS 108-05-4 and UN 1301, Class 3, Packing Group II. Under REACH, the substance is registered for monomer and intermediate uses, and downstream users are required to operate within the exposure scenarios for polymerisation and bulk handling. The closed-cup flash point of −8 °C places the product in the highly flammable liquid category; vapours are heavier than air and can travel to distant ignition sources. Vapour pressure at 20 °C is approximately 11.8 kPa, which requires fixed-roof tanks with nitrogen blanketing or pressure-vacuum vents that meet local emissions regulations. Skin and inhalation exposure boundaries are defined in the safety data sheet; engineering controls on multi-tonne continuous plants include closed-loop sampling, double mechanical seals on pumps, and continuous lower-explosive-limit monitoring during railcar and tank-truck unloading.
| Designation | Value | Basis |
|---|---|---|
| CAS number | 108-05-4 | Substance identity |
| UN number | 1301 | Class 3, Packing Group II |
| Flash point | −8 °C | ASTM D56 closed cup |
| Vapour pressure | 11.8 kPa at 20 °C | Published physical property |
In comparison with vinyl acetate monomer grades inhibited at 3–5 mg/kg or 14–17 mg/kg, the 25–30 mg/kg grade shifts the risk balance toward extended storage and away from immediate low-temperature processability. A lower-inhibitor grade may be preferred for a continuous latex train with rapid day-tank turnover, whereas the narrower 25–30 mg/kg band is selected for shared tank farms and export logistics where inhibitor depletion is the controlling risk. This distinction is not a final polymer property difference when initiator compensation is correctly sized; it is a difference in start-up behaviour, induction time, and storage safety margin.
