| HS Code | 580618 |
| Product Name | GOHSENOL EG-05PW |
| Chemical Family | Polyvinyl alcohol (PVOH) |
| Appearance | White powder |
| Degree Of Hydrolysis | 87.0 - 89.0 mol% |
| Viscosity | 4.6 - 6.0 mPa·s (4% aqueous solution at 20°C) |
| Ph | 5.5 - 7.5 (aqueous solution) |
| Ash Content | ≤ 0.5% |
| Volatile Content | ≤ 5.0% |
| Average Polymerization Degree | Approximately 500 |
| Solubility | Soluble in hot water |
As an accredited GOHSENOL EG-05PW factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | GOHSENOL EG-05PW is supplied as a white powder in 25 kg paper bags with a polyethylene liner. |
| Container Loading (20′ FCL) | 20' FCL: GOHSENOL EG-05PW (PVA powder) loaded in palletized, shrink-wrapped bags, ensuring dry, ventilated container to prevent moisture absorption. |
| Shipping | GOHSENOL EG-05PW is a polyvinyl alcohol grade typically shipped as a dry powder. It is non-hazardous under most transport regulations. Ship in sealed, moisture-proof packaging to prevent clumping. Keep away from humidity and direct sunlight during transit. Avoid generating dust; use clean, dry containers with proper labeling. |
| Storage | Store GOHSENOL EG-05PW (polyvinyl alcohol) in a cool, dry, well-ventilated area. Keep the container tightly sealed to prevent moisture absorption and contamination. Avoid exposure to high heat, direct sunlight, or ignition sources. Maintain storage temperatures typically below 40°C, and keep away from incompatible materials such as strong oxidizers. Follow all safety data sheet guidelines for optimal shelf life. |
| Shelf Life | Shelf life is typically 2 years when stored sealed, cool, and dry in original packaging. |
In vinyl acetate–ethylene and vinyl acetate–acrylic emulsion polymerisation, GOHSENOL EG-05PW is dissolved in demineralised water to a working solution of 10–12 wt% solids and introduced as a protective colloid at an addition level of 2.0–6.0 wt% on total monomer. The grade is a low-viscosity, partially saponified polyvinyl alcohol powder with a degree of hydrolysis of 86.5–89.0 mol% and a 4% aqueous solution viscosity of 4.8–5.8 mPa·s at 20°C per JIS K6726. That hydrolysis window provides sufficient interfacial activity for particle nucleation while retaining cold-water solubility after the latex is dried. In high-solids vinyl acetate–ethylene systems the low solution viscosity allows the pre-emulsion to be pumped through annular dosing lines without phase inversion at monomer feed times up to 4 h total addition. The terminal discharges are architectural coatings, nonwoven binders, and single-component assembly adhesives where residual hydrophilic colloid contributes to wet tensile development and redispersibility.
| Parameter | Reference method | Typical certificate of analysis range |
|---|---|---|
| 4% aqueous solution viscosity | JIS K6726 / ISO 2555 | 4.8–5.8 mPa·s at 20°C |
| Degree of hydrolysis | JIS K6726 | 86.5–89.0 mol% |
| pH | JIS K6726 | 5.0–7.0 |
| Loss on drying | JIS K6726 | ≤5.0% |
| Residue on ignition | JIS K6726 | ≤0.5% |
The polymerisation is commonly run in a jacketed stainless-steel reactor of 15–25 m³ working volume with an anchor impeller set to 30–50 rpm and a separately driven high-shear pre-emulsion tank. The initial reactor charge contains 60–70% of the total water, 1–2 wt% of the PVOH charge, and a buffering agent such as sodium bicarbonate to hold pH at 4.0–5.5. The residual monomer is fed over 3–4 h while ammonium persulfate at 0.2–0.5 wt% and sodium metabisulfite at 0.1–0.3 wt% are added as a redox couple. Jacket temperature is held at 72–80°C; excursions above 85°C can reduce protective-colloid solubility and generate coagulum on the vessel wall. After monomer addition, free monomer is steam-stripped to below 0.1 wt% and the batch is cooled through a plate heat exchanger before addition of post-stabilisers and biocides. Final latex solids are typically adjusted to 50–58 wt%, with Brookfield viscosity measured at 25°C per ISO 2555 and pH per ISO 976. Particle-size distribution is controlled by off-line dynamic light scattering per ISO 22412; typical vinyl acetate–ethylene grades show D50 values in the 0.15–0.35 µm range when protective colloid and low-surfactant emulsifiers are balanced.
Residual coagulum is typically quantified by passing the diluted latex through a 180 µm stainless-steel filter; incomplete PVOH dissolution caused by cold feed zones or rapid viscosity build appears as grit and increases filter residue. Batch-to-batch variance in this grade is controlled by checking the 4% solution viscosity of each incoming lot before charging, and by pre-dispensing the powder into a high-shear eductor to avoid fisheye formation. The dried latex film is evaluated for tensile strength and elongation per ISO 527-3 or ASTM D882. Where the latex is formulated for food-contact adhesive applications, supplier statements and finished formulation testing should be reviewed against 21 CFR 175.105 or 21 CFR 176.170 for the intended contact condition.
Remoistenable envelope flap adhesives are formulated with GOHSENOL EG-05PW at 10–18 wt% PVOH solids in water. The solution is prepared in a jacketed double-motion mixer at 85–90°C with a 30 min hold to complete hydration, then cooled to 40°C before borax addition. Borax at 0.5–2.0 wt% on PVOH solids forms a reversible di-diol complex that increases the effective molecular weight of the solution and raises Brookfield viscosity from 50–200 mPa·s to 500–3000 mPa·s at 25°C per ISO 2555. Humectant is added at 2–8 wt% and defoamer at 0.05–0.2 wt% to suppress foam entrainment during high-speed application. The adhesive is applied by wheel or nozzle applicator at 30–50°C to paper stock running at 50–200 m/min; final bond strength is measured by T-peel per ASTM D1876 after conditioning at 23°C and 50% RH.
The critical process conflict in borax-crosslinked systems is pH drift. Below pH 6.5 the crosslink density is insufficient and the compound can strike into porous paper; above pH 8.5 the borate complex can overbuild and cause irreversible gel grains that block applicator nozzles. A citrate or phosphate buffer at 0.1–0.3 wt% is used to hold pH at 6.8–8.0, but buffering capacity must be confirmed after borax addition because the pH of this PVOH grade varies with lot within the 5.0–7.0 certificate range. Storage above 40°C for more than 48 h can shift the borate equilibrium and must be validated by measuring viscosity recovery after cooling. Preservatives are added at 0.1–0.3 wt%; the chosen biocide must be compatible with the anionic charge of partially saponified PVOH. The terminal remoistenable adhesive complies with 21 CFR 175.105 for indirect food-contact adhesives when formulated with permitted humectants and biocides; paper-tube laminating grades are reviewed under 21 CFR 176.170 where the tube contacts dry food.
A blade coater running at 1200–1500 m/min requires a coating colour with high-shear viscosity low enough to prevent blade bleed, yet sufficient water retention to avoid binder migration. GOHSENOL EG-05PW is pre-dissolved at 12–15% solids and added at 0.3–1.5 parts per 100 parts of pigment. A representative formulation contains 100 parts ground calcium carbonate and kaolin, 8–12 parts styrene-butadiene latex, 0.5 part PVOH solids, 0.1–0.2 part sodium polyacrylate dispersant, and sodium hydroxide to pH 8.5–9.5. The colour is mixed under a high-speed disperser at 18–22 m/s tip speed and cooled to 25°C before viscosity measurement. The low degree of hydrolysis of the grade contributes moderate water retention without the disproportionate viscosity increase associated with fully hydrolysed PVOH, enabling final solids of 64–68% at application shear rates.
At the blade, shear rates exceed 105 s-1; capillary viscometry per ISO 2884 is used to model runnability, and low-shear Brookfield viscosity per ISO 2555 is recorded for batch control. Dry pick velocity measured by an IGT printability tester per ISO 3783 is recorded for the complete coating colour; the result is formulation-dependent and a meaningful comparison requires a latex-only reference under the same calendering conditions. Offset gloss measured per TAPPI T 480 and Parker Print-Surf roughness per ISO 8791-4 are monitored to ensure that the PVOH addition does not reduce calendering response. If the addition exceeds 1.5 parts, the wet colour can develop blade scratches and downstream doctor blade wear. The coated paper and board are intended for woodfree printing paper, label facestock, and folding carton grades; food-contact conformance is referenced to 21 CFR 176.180 and 21 CFR 176.170 for the dried coating in contact with aqueous and fatty foods.
On a multi-cylinder slasher processing spun polyester/cotton warps at 60–90 m/min, the size mix is built with 6–10 parts GOHSENOL EG-05PW, 0–4 parts oxidised starch, 0.3–0.8 part acrylic lubricant, and water to 100 parts. The mixture is jet-cooked at 85–90°C for 20–30 min, then held in a storage chest at 75–80°C. The partially saponified structure and low solution viscosity improve penetration into high-twist polyester yarns at size-box temperatures of 70–80°C. Squeeze rolls are set at 2–4 bar linear pressure to leave a size add-on of 8–12% on dry yarn. Drying cylinder temperatures are staged from 120°C to 100°C to avoid skinning on the yarn surface; skinning creates brittle shed dust in the weave room.
The sized warp is woven on air-jet looms at 500–700 rpm; warp yarn tensile strength is measured per ASTM D2256, and hairiness index is recorded by a Zweigle or Uster instrument before and after sizing. Abrasion resistance of the size film is evaluated in the weaving trial rather than on a coupon because reed impact and shed geometry cannot be fully reproduced off-line. The desizing step uses hot water at 80–90°C with 0.5–1.0 g/L nonionic wetting agent; the PVOH portion is removed without enzymatic action, while starch portions require alpha-amylase if blended. Effluent load is influenced by the PVOH chemical oxygen demand, and mill permits should be checked before converting from a starch-only formulation. The grade is supplied as a powder with a residual ash specification that is relevant for subsequent dyeing operations where calcium and ash can affect dye uptake; certificate of analysis limits should be confirmed for critical shades.
For mills with cold desizing capacity, the cold-water dissolution behaviour of the grade is an operational boundary. In winter intake water below 15°C the size film may require longer wash-box residence time or higher wetting-agent concentration. Published data for this specific grade in a high-speed mill setting is limited; a slasher trial should establish the minimum desizing temperature and wash-box capacity for the loom density.
Dry-pressing of technical ceramic bodies uses GOHSENOL EG-05PW at 1–2 wt% on dry powder mass as a temporary binder. It is dissolved at 10% solids in water and introduced into a ball-milled slurry containing alumina or zirconia powders, ammonium polyacrylate dispersant at 0.1–0.3 wt%, and deionised water to a solids loading of 50–65 wt%. The slurry is milled to the particle-size specification of the ceramic powder producer, then spray-dried through a rotary or nozzle atomiser at inlet 180–220°C and outlet 90–100°C. The resulting granulate must flow through shoe and die fill systems; granule size distribution is tracked by sieve mesh fraction retained at 45 µm and 150 µm. Pressing is conducted at 80–120 MPa on a hydraulic or mechanical press, and green density is calculated from geometric dimensions and dry mass.
Green strength is measured by three-point flexure per ASTM C1161 on pressed bars before sintering. Binder burnout is performed in air from 450–600°C at a heating rate of 0.5–2°C/min; the low residue-on-ignition specification of this PVOH grade supports controlled ash behaviour, but residual sodium from saponification must be checked lot-to-lot for low-alkali ceramics. If burnout is too rapid, carbon residues remain in closed porosity and can reduce fired density; if the binder addition is raised above 3 wt%, pressed parts may laminate at ejection because the polymer film reduces intergranular friction. The terminal applications are technical ceramic tiles, wear components, and electronic ceramic substrates where sintered properties are governed by the ceramic powder rather than the organic binder system. Published data for this specific configuration is limited; furnace profiling and green-strength testing on production tooling are required before replacing an incumbent binder.
When GOHSENOL EG-05PW is co-formulated with higher-DP partially hydrolysed PVOH at 10–30 wt%, the melt viscosity of the blend decreases and the heat-seal initiation temperature can be shifted downward by 5–15°C depending on plasticiser type and moisture content. The powder is pre-blended with plasticiser in a high-speed mixer, then fed to a single-screw extruder with an L/D ratio of 30:1 and a compression ratio of 2.5:1. Barrel temperatures are set from 160°C to 200°C, the melt is filtered through a screen pack, and cast film is produced through a slot die with a die gap of 0.5–0.8 mm. The resulting water-soluble film is oriented via machine-direction stretching and wound with interleaving paper to prevent blocking. Tensile strength and elongation are measured per ISO 527-3 at 23°C and 50% RH; seal strength is measured on a heat-seal tester per ASTM F88 after sealing at 180°C and 0.5 s dwell.
The operational boundary is ambient humidity. PVOH film equilibrates rapidly with ambient moisture; above 60% RH the film becomes tacky and blocking can occur on the roll, while below 25% RH the film embrittles. Roll stock is therefore packaged in barrier film with a moisture vapour transmission rate below 1.5 g/m²/day at 38°C and 90% RH. Cold-water dissolution time is measured in a stirred vessel at 20°C; the low-viscosity grade can shorten disintegration time compared with high-DP controls, but the result depends on film thickness, plasticiser content, and water hardness. Published data for this specific film configuration is limited; a laboratory blown-film or cast-film trial with the exact higher-DP partner grade is required. The film is intended for unit-dose detergent packets and agrochemical water-soluble bags, not for direct food contact unless the complete structure is evaluated under the relevant national regulation.
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GOHSENOL EG-05PW is a partially saponified polyvinyl alcohol powder supplied by Nippon Gohsei/Mitsubishi Chemical and positioned within the GOHSENOL EG series as a low-viscosity protective colloid for aqueous emulsion polymerization. Manufacturer literature identifies the grade by a 4 mass % aqueous solution viscosity of 4.5–5.5 mPa·s at 20 °C and a degree of hydrolysis of 86.5–89.0 mol% measured according to JIS K6726. The 05 viscosity designation separates it from higher-molecular-weight partially saponified grades such as EG-40 or EG-50, while the partial hydrolysis distinguishes it from fully saponified GOHSENOL N-series grades. The residual acetyl groups in EG-05PW disturb interchain hydrogen bonding, reduce crystallinity, allow cold-water dissolution, and alter interfacial activity during vinyl acetate and acrylic emulsion polymerization. These same structural features lower dry-film water resistance and hot-water resistance relative to fully hydrolyzed polyvinyl alcohol grades, so product selection depends on whether rapid cold-water make-down and low continuous-phase viscosity are more critical than barrier performance.
Analytical characterization of GOHSENOL EG-05PW is performed using JIS K6726 for viscosity, hydrolysis degree, volatile content, ash, and pH. International release documentation may reference ISO 15023-1:2017, although grade-specific specification limits are established by the manufacturer and should be verified against the current technical data sheet. The representative specification set for the powder is summarized in Table 1.
| Parameter | Representative value or limit | Test basis |
|---|---|---|
| 4 mass % aqueous solution viscosity at 20 °C | 4.5–5.5 mPa·s | JIS K6726 |
| Degree of hydrolysis | 86.5–89.0 mol% | JIS K6726 |
| Volatile content | ≤5.0 mass % | JIS K6726 |
| Ash content as Na₂O | ≤0.5 mass % | JIS K6726 |
| pH of 4 mass % aqueous solution | 5.0–7.0 | JIS K6726 |
Volatile content is a processing variable rather than a purity indicator. Powder stored at relative humidity above 60% may absorb sufficient moisture to interfere with precision weighing or melt compounding, and pre-drying in a vented oven at 60–80 °C is sometimes required before use. Ash content as sodium oxide reflects residual sodium acetate from the saponification step. In pH-sensitive redox initiator systems, that residual buffering capacity should be incorporated into the buffer calculation, especially when persulfate-bisulfite initiation is operated at pH values below 5.0.
The 86.5–89.0 mol% hydrolysis level places GOHSENOL EG-05PW in a structural window where cold-water solubility is retained but the polymer remains hydrophilic. In aqueous solution preparation, the powder is added slowly to room-temperature water under high-shear dispersion. A production-scale disperser with a rotor/stator head or a jacketed turbine mixer operating at 300–600 rpm is commonly used. The solution is initially mixed below 30 °C to avoid surface gelling, then heated to 70–80 °C for 30–60 min to complete hydration. Extended exposure to alkaline conditions at temperatures above 90 °C can hydrolyze residual acetate groups over time, causing viscosity drift and altered colloidal stabilization. Borate-based additives represent a known incompatibility because cis-diol sequences in polyvinyl alcohol form reversible but strong borate-diol complexes; the resulting viscosity increase and thermoreversible gelation should be evaluated by solution rheology rather than fixed addition thresholds. In dry storage, the product should be kept in closed containers below 30 °C and below 60% relative humidity to prevent caking and dust-layer microbial growth. The powder is not intended for direct melt processing without plasticizer; thermal discoloration and dehydration become significant above approximately 180 °C when melt residence time exceeds several minutes.
In vinyl acetate homopolymer and vinyl acetate-ethylene copolymer emulsion polymerization, GOHSENOL EG-05PW functions as a protective colloid and participates in graft polymerization through chain-transfer reactions. The reactor charge is typically prepared as a 5–10 mass % aqueous solution of the polyvinyl alcohol, combined with buffer, initial monomer, and initiator in a jacketed, baffled reactor with an anchor impeller. The low 4.5–5.5 mPa·s solution viscosity supports high-solids formulations without excessive continuous-phase viscosity, but the lower molecular weight also reduces steric layer thickness. When replacing a fully saponified grade, the protective colloid concentration may need to be adjusted upward to maintain equivalent particle size and freeze-thaw stability. Fully saponified GOHSENOL grades require solution make-up temperatures above 80 °C, which slows batch turnaround and increases thermal load. EG-05PW dissolves at 20–30 °C, allowing direct make-down in unheated mixing vessels. The partially saponified structure introduces acetyl groups at the particle surface, reducing interfacial free energy with vinyl acetate monomer but depressing water resistance of the dried film. The grade is therefore selected for interior paints, adhesives, and non-structural binders where redispersibility or cold-water re-wetting is advantageous. Final emulsion viscosity and particle size distribution should be determined by rotational viscometry and laser diffraction because published grade-specific data across all reactor configurations is limited.
The principal performance differences are summarized in Table 2. The comparison is directional and is intended for grade-selection screening; final specification decisions require lot-specific release data and end-use testing under the relevant application conditions.
| Attribute | GOHSENOL EG-05PW | Higher-viscosity partially saponified grade | Fully saponified grade |
|---|---|---|---|
| 4 mass % solution viscosity at 20 °C | 4.5–5.5 mPa·s | typically greater than 20 mPa·s | grade-dependent, often 10–60 mPa·s |
| Cold-water dissolution | rapid at 20–30 °C | moderate; may require 30–50 °C | requires 80–95 °C |
| Film water resistance | reduced | moderate | high |
| Continuous-phase viscosity in emulsion polymerization | low | high | moderate to high depending on molecular weight |
| Typical role | low-viscosity protective colloid | viscosity build and high-shear stabilization | water-resistant film formation and crosslinkable binder |
High-solids converting and adhesive compounding uses GOHSENOL EG-05PW when moderate wet tack is required at low application viscosity. In remoistenable adhesive operations, the grade can be incorporated as a colloid stabilizer and binder at dry addition levels of 2–5 parts per hundred of total formulation solids. The dissolution rate at 20–30 °C permits direct make-down in unheated mixing vessels, while the low viscosity contribution supports blade-coating and roll-coating equipment at line speeds common to paper converting. However, the residual acetyl content reduces wet bond retention on fully saturated paperboard. Adhesion testing under ASTM D903-98 or equivalent peel methods and exposure at 85% relative humidity is recommended before substituting the grade into a specification. The product is less suitable for boil-proof or structural wood adhesives, where fully saponified or crosslinked polyvinyl alcohol systems are normally specified.
Regulatory documentation for GOHSENOL EG-05PW is end-use specific and should be obtained from the manufacturer because food-contact clearances depend on the final article and migration limits. Polyvinyl alcohol grades of this chemistry are commonly referenced in 21 CFR 176.170, 21 CFR 176.180, and 21 CFR 175.105 for paper and paperboard or adhesive applications, but use in food packaging must be confirmed against final-article migration testing under EU Regulation 10/2011 or equivalent national legislation. RoHS Directive 2011/65/EU does not regulate bulk polyvinyl alcohol as an electrical/electronic component; however, suppliers may provide absence declarations for restricted heavy metals and phthalates on request. REACH registration under Regulation (EC) No 1907/2006 applies to the substance as manufactured or imported, and the downstream user is responsible for verifying exposure-scenario compatibility.
