| HS Code | 703755 |
| Chemical Name | Polyvinyl alcohol |
| Cas Number | 9002-89-5 |
| Appearance | White to cream granular powder |
| Odor | Practically odorless |
| Degree Of Hydrolysis | 98.0-98.8 mol% |
| Viscosity 4 Percent Solution At 20c | 10-14 cP (mPa·s) |
| Ph 4 Percent Solution | 5.0-7.0 |
| Ash Content | ≤ 1.0% |
| Volatiles Content | ≤ 5.0% |
| Water Solubility | Soluble in hot water (above 80°C); disperses in cold water |
| Specific Gravity | 1.25-1.30 |
| Melting Point | 220-230°C |
| Glass Transition Temperature | 75-85°C |
| Refractive Index | 1.49-1.53 |
As an accredited SELVOL Polyvinyl Alcohol 443 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | SELVOL Polyvinyl Alcohol 443 is packaged as free-flowing granules in 25 kg multi-wall paper bags with inner liner, palletized shrink-wrapped. |
| Container Loading (20′ FCL) | 20′ FCL container loaded with SELVOL Polyvinyl Alcohol 443, palletized and secured for safe, efficient transport. |
| Shipping | SELVOL Polyvinyl Alcohol 443 ships as a non-hazardous, water-soluble resin powder. Pack in sealed, moisture-resistant bags or containers, protected from humidity and direct sunlight. Avoid generating dust; keep dry during transit. Standard dry freight transport is suitable, with proper labeling and handling per SDS guidelines. |
| Storage | Store SELVOL Polyvinyl Alcohol 443 in a cool, dry, well-ventilated area away from heat, open flames, and strong oxidizers. Keep containers tightly closed to prevent moisture absorption and dust accumulation. Avoid direct sunlight and extreme temperatures. Ensure proper labeling and segregation from incompatible materials. |
| Shelf Life | Shelf life is typically 2 years when stored in original, unopened packaging in a cool, dry area. |
In vinyl acetate-ethylene (VAE) dispersion synthesis, SELVOL Polyvinyl Alcohol 443 functions as a protective colloid during micellar nucleation and particle growth. A 4% aqueous solution at 20°C exhibits a Brookfield viscosity of 5.2–6.2 cP when measured by ISO 2555, and the 87–89 mol% hydrolysis level leaves a controlled acetate content that moderates grafting during free-radical polymerization. A jacketed stainless steel reactor fitted with an anchor or pitched-blade turbine is typically charged with a 10–15 wt% PVOH premix that has been fully dissolved at 80–90°C for 60–90 minutes. Continuous or delayed feed of 2.5–5.0 wt% PVOH based on total monomer is common in batch and semi-batch operation, with additional surfactant kept below 1.0 wt% where required. At reaction temperatures of 60–85°C under persulphate or redox initiation, the molecular weight distribution of 443 supplies colloidal stability without generating the exceptionally high reactor viscosity associated with higher-molecular-weight PVOH grades. The main incompatibility arises from borate salts and polyvalent cations: if Ca²⁺ exceeds 100 mg/L in the premix water, gelation can occur before the reaction starts. Demineralised water with conductivity below 10 µS/cm is therefore specified for solution preparation. Foam generation during stripping and monomer addition is controlled by maintaining agitator tip speed at or below 1.2 m/s, and antifoam input above 0.05 wt% should be avoided because residual antifoam migrates into the finished dispersion as surface defects.
In paper and board surface sizing, 443 is combined with oxidized or cationic starch at the size press to reduce oil absorption and improve IGT pick resistance. The 5.2–6.2 cP viscosity of a 4% aqueous solution permits transfer from a rod-metered size press at 80–150 m/min without misting or blade scratches. A typical size press formulation contains 0.3–2.0 dry parts PVOH per 100 dry parts starch plus 0.05–0.15 parts defoamer. The grade is first dispersed in cold water at 25–40°C and then heated to 90–95°C for 60 minutes to complete hydration. Because the hydrolysis level is 87–89 mol%, the dried size film has limited water resistance compared with fully hydrolysed 98–99 mol% PVOH grades; this property is intentionally used in paper broke recovery, because the partially hydrolysed film swells rapidly during repulping. Cobb60 water absorption is measured by ISO 535, and actual values are controlled primarily by the starch ratio rather than by PVOH alone. The size press liquor should be held between pH 6.0 and 8.5, since alkaline pH above 9.0 in the presence of borate ions or persulphate residues can produce viscosity creep and uneven film formation. If higher water resistance is required, the grade is partially substituted with a fully hydrolysed PVOH or a styrene acrylic copolymer; however, 100% substitution is not recommended where low-effluent repulping is an operational requirement.
| Application segment | Standard or method | Critical parameter and condition |
|---|---|---|
| PVOH solution viscosity | ISO 2555 | 4% aqueous, 20°C, 5.2–6.2 cP |
| Paper sizing water absorption | ISO 535 | Cobb60 at 23°C |
| Adhesive food-contact clearance | FDA 21 CFR 175.105 | Dried adhesive film, indirect food contact |
| Warp yarn tenacity retention | ISO 2062 | Warp yarn at 8–15 wt% add-on |
| Nonwoven strip tensile | ASTM D5035 | 50 mm jaw gap, 300 mm/min |
In remoistenable and water-borne adhesive systems, a 7–12 wt% aqueous solution of 443 is plasticized with glycerol, sorbitol or polyethylene glycol 200 at 5–15 wt% on dry PVOH. Compounded adhesive viscosity generally falls between 1,500 mPa·s and 4,000 mPa·s at 25°C when measured by ISO 2555, and this range supports roller, extrusion and die coating without stringing. Adhesive film applied at 1.5–3.0 g/m² dry coat weight on envelope flaps or labels can be remoistened within 2–5 seconds at 20–25°C and 50–60% RH. Dried films remain water soluble, so blocking resistance under humid storage is improved by reducing plasticizer content to below 8 wt% and adding 2–5 wt% polyvinyl acetate emulsion. At relative humidity above 75%, the adhesive film absorbs moisture and bond strength declines. If greater moisture resistance is required, glyoxal at 0.05–0.2 wt% can be used as a crosslinker, but viscosity stability must be verified because glyoxal reacts with residual acetate under acidic pH below 4.5. For food packaging applications, the dried adhesive film is subject to FDA 21 CFR 175.105.
For high-speed shuttleless weaving of polyester/cotton ring-spun yarns, 443 is applied as a warp size film at 8–15 wt% add-on on yarn dry weight. A typical size formulation contains 12–18 wt% PVOH 443 as dry solids in the size bath, 3–6 wt% lubricant or wax based on PVOH solids, and 0.2–0.5 wt% wetting agent. The size bath is held at 80–85°C and applied by a multi-cylinder slasher; squeeze pressure is adjusted to 25–35 kN/m to control add-on and film thickness. Drying cylinder surface temperatures are maintained at 120–135°C to avoid excessive crystallization and size dusting. Below 6 wt% add-on, yarn hairiness increases and end breaks rise under high-speed shedding; above 18 wt% add-on, size shed and reed deposits become difficult to control. Weaving performance is assessed by warp stop levels and yarn tenacity retention per ISO 2062. Desizing is performed with hot water at 70–80°C without enzymes because the 87–89 mol% hydrolysis permits swelling and removal within 10–20 minutes in continuous desizing ranges. The main operational boundary is viscosity drift when the size bath is recirculated: above 85°C, evaporation raises concentration and viscosity, so demineralised water must be added to maintain a 5.2–6.2 cP base solution at 4% solids.
In air-laid, wet-laid and lightly carded nonwoven manufacture, 443 is sprayed or foam-applied as a binder for cellulose and synthetic staple webs. A solution concentration of 4–8 wt% is applied at 20–40 g/m² wet add-on and dried at 110–140°C in through-air drum dryers. Dry nonwoven tensile strength is evaluated by ASTM D5035. The use window is narrow when dispersibility is required because overdrying above 140°C reduces cold-water dispersibility of the partially hydrolysed binder.
In aqueous ceramic slurry preparation for tape casting and spray-dried powder pressing, 443 is added at 0.5–2.0 wt% based on dry ceramic mass to provide green strength and controlled burnout. The grade is pre-dissolved at 10–15 wt% solids and blended into alumina or barium titanate slurries at 20–30°C. Excess addition above 3.0 wt% causes binder migration to the tape surface during drying and increases ash residue. Binder burnout is performed at 350–450°C in air. The sodium ash content of the PVOH grade is below 0.5 wt%, which suits dielectric and structural ceramic formulations. Published data for this specific Selvol 443 grade in aqueous tape casting is limited; processing guidelines derive from general PVOH binder systems. Powder stored outside moisture-barrier packaging at RH above 60% requires pre-drying at 70–80°C for 2–4 hours in a desiccant dryer to restore free flow and gravimetric dosing accuracy.
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SELVOL Polyvinyl Alcohol 443 is a low-viscosity, partially hydrolyzed polyvinyl alcohol resin supplied as a white to off-white granular powder. The grade is produced by alcoholysis of polyvinyl acetate, leaving residual acetate groups that place it in the 87.0–89.0 mol% hydrolysis range. A 4% aqueous solution at 20 °C exhibits a nominal rotational viscometer viscosity of 3.5–4.5 mPa·s when measured in accordance with ISO 15023-2. Because the product is not plasticized or surfactant-modified, solution rheology and film formation are governed by polymer molecular weight, acetate content, and solids concentration. In the SELVOL portfolio, this combination of partial hydrolysis and low solution viscosity selects for applications requiring cold-water dispersibility, higher solids at manageable mixer torque, and moderate film cohesion, while limiting suitability for applications requiring high wet strength or hot-water resistance.
The certificate of analysis for SELVOL 443 typically reports the properties shown in the following table. Viscosity is determined on a 4% solution prepared by dissolving dry resin in deionized water at 90 °C for 30 min and equilibrating to 20 °C. Hydrolysis degree is determined by saponification back-titration of residual acetate groups. The values are manufacturer-published ranges, not batch-specific results.
| Property | Method | Specification |
|---|---|---|
| Hydrolysis degree | ISO 15023-2 | 87.0–89.0 mol% |
| Viscosity, 4% aqueous solution at 20 °C | ISO 15023-2 | 3.5–4.5 mPa·s |
| Volatile matter | ISO 15023-2 | ≤ 5.0% |
| Ash | ISO 15023-2 | ≤ 0.5% |
| pH, 4% solution | ISO 15023-2 | 4.5–6.5 |
In jacketed stainless-steel mix tanks equipped with an axial-flow impeller and a powder eductor, the dry resin is metered into ambient water at 15–25 °C before heat is applied. Heating is then increased to 85–90 °C and held for 30–45 min until a clear solution is obtained. Powder addition directly into water above 70 °C causes particle surface gelation and lump formation; the resulting lumps have a dry core and require shear above 3 m/s to disperse. For 10–15% solids batches, a low-pressure steam jacket and a slow-speed anchor or pitched-blade turbine are generally sufficient, but air entrainment can produce stable foam that interferes with coating weight control and leveling. A defoamer may be added at 0.01–0.05 wt% on total batch. The solution is pseudoplastic at polymer concentrations above approximately 6–8%, so viscosity comparisons require a controlled spindle speed, equilibration time, and temperature.
Adhesive formulations use SELVOL 443 where low solution viscosity permits 25–40% solids with acceptable transfer pump pressure. In remoistenable coatings, the dry film must remain continuous and non-blocking while rewetting speed is controlled by the residual acetate content. Blocking resistance is formulation-specific and is typically evaluated with a heated plate or humidity chamber rather than a single standardized method. Dry film tensile properties can be measured by ASTM D882-18, and water resistance of the bond line must be validated under the intended end-use humidity because partially hydrolyzed films redisperse more readily than fully hydrolyzed films. In vinyl acetate and vinyl acetate-ethylene emulsion polymerization, SELVOL 443 functions as a protective colloid. Addition levels of 2–6 wt% based on total monomer produce latexes with a broad particle size distribution and shear-thinning flow. Latex viscosity can be measured with ASTM D2196-20, and coagulum content is determined by filtration through a 106 µm sieve. The low molecular weight of the grade reduces aqueous-phase thickening relative to higher-viscosity PVOH, which can allow higher reactor solids before reaching a viscosity limit imposed by cooling jacket and stirrer capacity.
Paper surface sizing at a puddle or metered size press uses SELVOL 443 at 2–6% total solids, often in combination with oxidized corn starch. The PVOH-to-starch dry ratio typically ranges from 1:10 to 1:3. In this application, water absorption of the sized sheet can be measured by Cobb60 according to ISO 535:2014, and surface strength can be measured with an IGT pick test according to ISO 3783:2014. Because the grade is partially hydrolyzed, it provides less water resistance after drying than fully hydrolyzed grades; therefore, replacement of a fully hydrolyzed grade in a given furnish should be tested at the same solids and size press pickup. In pigment coating, SELVOL 443 may be used as a co-binder with styrene-butadiene latex at 0.2–0.8 parts per hundred pigment. Low solution viscosity reduces blade pressure on the coater and can improve dry pick resistance, but wet pick and water sensitivity must be checked when latex content is reduced.
Textile warp sizing uses low-viscosity PVOH to maintain size-box solids between 8% and 12% while controlling add-on on high-speed slashers. The film from SELVOL 443 is cold-water removable, which supports desizing, but its tensile strength on polyester/cotton warp yarns may be lower than higher-viscosity partially hydrolyzed grades. Slasher squeeze roll pressure, dry-can temperature, and size-vat viscosity should be revalidated when switching from a 25–30 mPa·s grade to this 3.5–4.5 mPa·s grade because threadline carry-over and size penetration can change. In water-soluble film casting, SELVOL 443 can be used for solution-cast films, but the low molecular weight reduces puncture resistance relative to fully hydrolyzed or higher-viscosity partially hydrolyzed films. Film tensile properties are measured per ASTM D882-18; in multilayer water-soluble packaging, SELVOL 443 is sometimes used as a thin tie or release layer rather than the structural layer.
The principal selection variables in the SELVOL series are hydrolysis degree and 4% solution viscosity. Residual acetate groups in the 87.0–89.0 mol% range interfere with crystallite packing, lowering the dissolution temperature and reducing hot-water resistance relative to fully hydrolyzed grades. Within the partially hydrolyzed series, viscosity correlates with molecular weight and controls film strength, solution thickening efficiency, and protective-colloid performance. The following comparison summarizes the practical consequence of shifting these variables.
| Grade | Hydrolysis degree | 4% viscosity at 20 °C | Practical consequence |
|---|---|---|---|
| SELVOL 403 | 87.0–89.0 mol% | 2.5–3.5 mPa·s | lowest film strength; highest cold-water dissolvability; high solids possible |
| SELVOL 443 | 87.0–89.0 mol% | 3.5–4.5 mPa·s | low-viscosity balance of film cohesion and solution flow |
| SELVOL 325 | 87.0–89.0 mol% | 28.0–32.0 mPa·s | higher film strength; higher thickening; lower solids at equal pump viscosity |
| SELVOL 502 | 98.0–98.8 mol% | 2.5–3.5 mPa·s | fully hydrolyzed; improved water resistance and film strength; requires hot-water make-down |
Switching from SELVOL 502 to SELVOL 443 changes the water-resistance profile of a dried adhesive film because the residual acetate groups in the partially hydrolyzed grade act as internal plasticizers. This can increase cold-water tack and lower the dissolution temperature, but the dry film will have lower tensile strength and higher equilibrium moisture uptake at 50% RH. Conversely, switching from SELVOL 443 to SELVOL 325 increases dynamic solution viscosity by approximately 8–9 times at the same solids and raises the mechanical load on transfer pumps; processing parameters should not be assumed to remain transferable. Mixing torque, spray nozzle pressure, size press pickup, and latex reactor stirring all respond nonlinearly to this viscosity shift.
Operational boundaries and incompatibilities must be considered before replacing an existing grade. SELVOL 443 is not recommended for immersion service or for films that must retain integrity in water above 40 °C unless crosslinked. In partially hydrolyzed form, dry films are redispersible in cold water, which makes them unsuitable for water-resistant structural adhesives without chemical crosslinking. Common crosslinking agents include glyoxal, zinc nitrate, and melamine-formaldehyde resins, but their addition can reduce pot life and shift pH; pot life must be revalidated by rheological measurement rather than visual appearance. The powder is combustible as a dust; dust control must comply with NFPA 652 and local ATEX requirements. Strong oxidizing agents, concentrated mineral acids, and high levels of borate ions should be avoided or strictly controlled because borate ions produce reversible di-diol crosslinks that can transition to irreversible gelation above a formulation-specific threshold near 1.0 wt% of PVOH solids. Solutions are subject to microbial growth; preservation is required for storage beyond 48 h. Powder storage should be maintained below 30 °C and below 60% RH to prevent caking and lump formation during make-down.
Regulatory status is not a performance property, but it is a constraint for formulated articles. In food-contact adhesives, the relevant U.S. FDA framework is 21 CFR 175.105; in paper and paperboard, 21 CFR 176.170 and 21 CFR 176.180 may apply, and for polyvinyl alcohol film, 21 CFR 177.1670 may apply. EU users should verify that the monomer and additives are registered under REACH and that the grade meets the relevant migration limits for the intended food type under Regulation (EU) No 10/2011, as amended. The product is not supplied with a blanket food-contact certification because migration, coating weight, and end-use conditions are article-specific. When regulatory clearance is claimed, the finished article must be tested under the intended contact time, temperature, food simulant, and surface-to-volume ratio.
