| HS Code | 273353 |
| Product Name | GOHSENX K-434 |
| Material Type | Ethylene-Vinyl Alcohol Copolymer (EVOH) |
| Physical Form | Pellets |
| Ethylene Content | 34 mol% |
| Density | 1.18 g/cm³ |
| Melt Flow Rate 210 C 2 16 Kg | 5.0 g/10 min |
| Melting Point | 183°C |
| Glass Transition Temperature | 61°C |
| Tensile Strength At Break | 82 MPa |
| Elongation At Break | 250% |
| Tensile Modulus | 2.7 GPa |
| Oxygen Permeability 20 C 65 Rh | 0.3 cm³·mm/m²·day·atm |
| Water Absorption 24h | 8.0% |
| Optical Property | Transparent |
As an accredited GOHSENX K-434 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | GOHSENX K-434 is supplied in 25 kg multi-layer paper bags with a polyethylene liner for safe handling. |
| Container Loading (20′ FCL) | GOHSENX K-434 shipped in 20′ FCL: drums on heat-treated pallets, unitized with stretch wrap, secured, and within gross weight limits. |
| Shipping | GOHSENX K-434 (polyvinyl alcohol powder) is shipped as a dry, free-flowing solid in multi-layer paper bags or lined drums. It is not classified as dangerous goods for road, sea, or air transport. Keep containers sealed and protected from moisture, and avoid dust generation during handling. Standard dry container conditions are suitable. |
| Storage | Store GOHSENX K-434 in its original, tightly sealed container in a cool, dry, well-ventilated area away from direct sunlight, heat, and ignition sources. Protect from moisture and humidity, as the material can absorb water. Keep separate from strong oxidizing agents and incompatible chemicals. Follow manufacturer’s shelf-life recommendations and handle with appropriate PPE. |
| Shelf Life | The shelf life of GOHSENX K-434 is typically 2 years from manufacture when stored in a cool, dry place. |
GOHSENX K-434 is supplied as a fully hydrolysed polyvinyl alcohol with a 4% aqueous solution viscosity of 22.0–26.0 mPa·s at 20°C, degree of hydrolysis 98.0–99.0 mol%, ash content ≤0.5%, and volatile content ≤5.0%. Complete dissolution requires process water at 85–95°C under moderate shear; the grade is not cold-water soluble. The downstream scenarios below are restricted to industrial uses for which the viscosity–hydrolysis combination is specified.
In continuous and batch emulsion polymerisation of vinyl acetate and vinyl acetate-ethylene monomers, GOHSENX K-434 functions as a steric protective colloid rather than a primary emulsifier. The grade is pre-dissolved in demineralised water at 10–12 wt% by heating to 90°C and holding for 60 min; the solution is filtered through a 180–250 µm sieve before charging. In a 30 m³ stainless-steel jacketed reactor equipped with dual pitched-blade turbines and a wall-scraping anchor, the aqueous charge is adjusted to pH 4.0–5.0 before monomer feed. The addition ratio is controlled at 1.0–4.0 wt% on total vinyl acetate monomer; for high-solids vinyl acetate-ethylene dispersions targeting 55–60% solids and final dispersion viscosity of 2,000–4,000 mPa·s at 25°C, the narrower control window of 1.5–2.5 wt% is applied to avoid shear-thickening during downstream coating. Production process includes staged ethylene addition at 20–50 bar, redox initiation with tert-butyl hydroperoxide and sodium metabisulfite at 60–75°C, post-polymerisation residual monomer stripping, neutralisation with sodium hydroxide, and final filtration through 100–150 µm bag filters. Compliance is demonstrated by ISO 3251:2019 for non-volatile content, ISO 2555:2018 for Brookfield viscosity, and FDA 21 CFR 175.105 where the resulting dispersion is used as an indirect food-contact adhesive. Finished products include D3 and D4 woodworking adhesives classified under EN 204, paperboard lamination adhesives, and removable aqueous peelable coatings. On a production line converting from protein-stabilised polyvinyl acetate to K-434, batch-to-batch final viscosity variation remains below 5% when the PVOH solution is held above 70°C prior to metering, preventing retrogradation and gel-layer accumulation in the feed manifold.
The interaction between fully hydrolysed PVOH and cellulose fines determines short-term rheology at the size press. For coated fine paper and bleached board, GOHSENX K-434 is cooked in a stainless-steel jet cooker at 90–95°C and diluted to a surface sizing solution of 3–6% solids; the addition ratio in pigmented coating colour is 0.5–1.5 parts per 100 parts dry pigment, while separate surface sizing formulations use 2–5 wt% of total size solution. Process equipment includes a film press or puddle size press with metering rod pressure at 0.5–1.5 bar. On a high-speed fine paper machine running at 1,200 m/min, size press pick-up is maintained at 2.5–3.5 g/m² dry film. Compliance for food-contact paper and board is evaluated under FDA 21 CFR 176.170 and BfR Recommendation XXXVI; water absorption is tested by ISO 535 Cobb60. Finished product types include release liner base papers, inkjet receiving layers, single-coated folding boxboard, and grease-resistant food-service board. The grade is not suitable for cold-set short-dwell coating colour when the 4% solution viscosity exceeds 26 mPa·s because blade runnability decreases; borate-containing wet-end additives must be excluded from the furnish, as borate addition causes immediate gellation of fully hydrolysed PVOH.
In dry-pressed technical ceramic bodies, the binder phase must deliver green strength without leaving metallic residues after burnout. GOHSENX K-434 is added at 0.3–1.0 wt% based on dry ceramic body weight, typically as a 5–8 wt% aqueous solution into the ball mill charging tank. The production process for spray-dried granules includes wet milling in an alumina-lined ball mill at 45–55% solids, spray drying through a rotary atomizer with inlet air at 220–250°C and outlet temperature 90–110°C, sieving to a 63–200 µm granule fraction, dry pressing at 35–45 MPa, and binder burnout in air at 350–450°C before sintering. The grade leaves sodium ash below 0.5%, which is critical for alumina and zirconia bodies where residual alkali modifies sintering kinetics. Compliance is anchored to ISO 12677:2011 for ceramic and refractory raw material chemical analysis, REACH (EC) 1907/2006 for European market registration, and RoHS Directive 2011/65/EU where the finished ceramic component enters electrical and electronic equipment. Finished product types include porcelain tile bodies, alumina electronic substrates, silicon nitride green machined parts, and cordierite honeycomb catalyst carriers. On a production press line using 45 MPa specific compaction pressure, granule crush strength and green density increase linearly up to 1.0 wt% binder addition; above this threshold, green body density decreases because organic volume displaces ceramic packing and delamination in ejection increases. The operational boundary is therefore stated as 0.3–1.0 wt%; no borate, chromate, or amine crosslinker is required, and excess moisture above 1.5% in dried granules causes punch sticking on multi-cavity tools.
On single-size-box slashers processing 40–80 Ne polyester/cotton warps at 60–90 m/min, GOHSENX K-434 is used as the high-viscosity component of a size formulation that replaces polyacrylic acid esters in woven fabric production. The addition ratio is 25–45% of total dry size solids, with the balance supplied by oxidized starch and lubricant; total size box solids are maintained at 7–12%, and the K-434 portion is pre-dissolved at 10–12 wt% and then blended with starch at 85–95°C. High-pressure squeeze rolls are set at 10–15 kN/m nip load to achieve 8–12% size add-on on warp yarns. Compliance for restricted substances is evaluated against ZDHC MRSL v3.1; finished fabric chemical residues are tested according to OEKO-TEX Standard 100 where the end-use requires skin-contact class II. Desizing uses hot-water washing at 85–95°C, followed by amylase treatment for starch and oxidative desizing for PVOH recovery; the grade is not cold-water desizable and is not appropriate for low-temperature energy-saving desizing lines. Finished products include woven shirting, lining fabrics, workwear, and automotive interior fabrics. On high-speed air-jet looms, weaving efficiency is maintained only when the size film modulus and hairiness coverage are stable; batch-to-batch variation in K-434 solution viscosity is controlled by dissolving at 90°C for 45–60 min until clear and filtering through 100 µm screens to prevent undissolved gel slubs in the size box.
Paper-faced gypsum board manufacture uses high-molecular-weight PVOH to modify filtration loss at the liner paper interface and to strengthen the rehydrated gypsum matrix. GOHSENX K-434 is dry-blended with stucco at 0.1–0.5 wt% based on dry gypsum, or injected as a 5% aqueous solution into the mixer after foam generation. Process route includes a continuous pin mixer with a residence time of 3–8 s, forming between two paper liners, setting on a belt at 30–40% relative humidity, and board drying at 180–250°C core temperature. Compliance is demonstrated under ASTM C1396/C1396M for gypsum board and EN 520 for European market boards; face-paper adhesion is measured by ASTM C473. Finished product types include standard and moisture-resistant paper-faced gypsum board, glass mat faced gypsum panels, and ready-mixed joint compounds. The operational limitation is that PVOH addition above 0.5 wt% increases slurry viscosity and foam collapse, while addition below 0.1 wt% does not reproducibly increase paper bond; published data for the specific K-434 grade in fire-rated type X board is limited, so plant trials with cone penetration and water demand measurement are required before continuous production.
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GOHSENX K-434 is a partially hydrolysed polyvinyl alcohol resin supplied by Mitsubishi Chemical Corporation under CAS 9002-89-5. The grade is specified for applications requiring a degree of polymerisation near 2400 and a controlled residual acetate content of 11.0–13.0 mol%. Its manufacturer-published specification includes a 4% aqueous viscosity at 20 °C of 48.0–58.0 mPa·s, saponification degree of 87.0–89.0 mol%, volatile matter not exceeding 5.0%, ash content not exceeding 0.5%, and pH in 4% solution of 5.0–7.0. It is supplied as free-flowing granules and is typically introduced at 2–6 wt% on monomer in emulsion polymerisation or at 5–10 wt% solids in paper-coating formulations. These values are determined according to JIS K 6726; viscosity is commonly read on a Brookfield rotational viscometer at 20 °C.
Incoming inspection should focus on viscosity, hydrolysis, ash, and moisture because these parameters control dissolution behaviour, adhesion, and final film properties. Ash content above 0.5% can accumulate on blade-coater edges and raise the coefficient of friction in dried PVOH films. Volatile matter above 5.0% in moist storage conditions indicates water uptake, which can reduce the accuracy of formulated solids and make hopper feeding unreliable. A pH below 5.0 in the 4% aqueous stock may accelerate ester hydrolysis during extended holding, while a pH above 7.0 can indicate residual alkaline salts that influence crosslinker reactivity.
| Parameter | Specification | Test basis |
|---|---|---|
| 4% aqueous viscosity | 48.0–58.0 mPa·s | JIS K 6726, Brookfield rotational viscometer, 20 °C |
| Saponification degree | 87.0–89.0 mol% | JIS K 6726, titration |
| Degree of polymerisation | approx. 2400 | viscosity-average process control |
| Volatile matter | ≤ 5.0% | drying at 105 °C |
| Ash content | ≤ 0.5% | ignition residue |
| pH | 5.0–7.0 | 4% aqueous solution, 20 °C |
These limits are not merely descriptive. In emulsion polymerisation, a shift in saponification distribution from 87.0 to 89.0 mol% can alter grafting behaviour and colloidal stability. In paper coating, an increase in ash content of 0.1% may not affect laboratory hand-sheets but can produce visible streak defects on commercial blade coaters running above 800 m/min. Plants that run continuous dissolution systems therefore quarantine incoming lots until viscosity and moisture are confirmed against the purchase specification.
Solution preparation on production scale begins by dispersing granules into demineralized water at 25–30 °C under agitation in a jacketed vessel equipped with a propeller or anchor impeller. The slurry is then raised to 85–95 °C over 40–60 min and held until the solution clears. High-shear rotor-stator mixers are not recommended because they pull air into the solution and generate gel specks; impeller tip speed should remain below 2.5 m/s during the heat-up phase. At a make-up concentration of 4%, the final solution exhibits a Brookfield viscosity of 48–58 mPa·s at 20 °C, but this value falls sharply as temperature increases to 60 °C. The solution should not be held above 95 °C for more than 60 min; prolonged heating can hydrolyse residual acetate groups and cause yellowing or free acetic acid odour. Granule moisture uptake in unsealed silos above 60% relative humidity can raise volatile matter above 5.0%; production sites in humid climates use dry-air purging at a −40 °C dew point or install hopper heaters with moisture controls.
In suspension and emulsion polymerisation, GOHSENX K-434 functions as a high-DP protective colloid rather than a conventional low-molecular-weight surfactant. It is charged as an aqueous stock at 5–10% concentration into a glass-lined stirred reactor of 10,000–20,000 L working volume, with PVOH addition fixed at 2–6 wt% relative to vinyl acetate monomer. The residual acetate content of 11.0–13.0 mol% participates in chain-transfer and grafting reactions with the growing acetate radical, anchoring the steric stabilisation layer around polymer particles. Unlike sodium lauryl sulfate or nonylphenol ethoxylate surfactants, the grafted PVOH remains in the dried film and contributes cohesive strength rather than migrating to the adhesive interface.
Finished emulsion viscosity at 55% solids and 25 °C commonly falls in the range 8,000–16,000 mPa·s when measured with a Brookfield RVT viscometer, spindle 5 at 20 rpm. Particle-size analysis by laser diffraction on a Malvern Mastersizer 3000 typically shows D50 between 1.0 µm and 2.5 µm for this mode of stabilisation, but the exact distribution depends on the monomer addition profile and the stirring energy input. A production-scale bottleneck is the blind filtration of coagulum: if latex is discharged through 100 µm stainless-steel mesh at 40 °C, fouling accelerates when the system pH drifts below 3.0 or when the jacketed reactor hot-spot exceeds 80 °C. Operators therefore trim buffer addition to maintain pH 4.0–5.5 and limit the initiator shot to avoid a temperature overshoot of more than 5 °C. Published data for this specific reactor configuration is limited; most plant programmes rely on wet-set redispersibility and accelerated storage tests at 50 °C rather than datasheet values alone.
The grade is not a universal emulsifier for non-polar monomers such as styrene. In styrene-butyl acrylate systems, a secondary anionic surfactant is generally required because PVOH surface activity is insufficient to stabilise the more hydrophobic monomer droplets. For vinyl acetate homopolymer and vinyl acetate-ethylene latexes, GOHSENX K-434 can replace part or all of the conventional post-added thickener, reducing the total number of wet ingredients and improving water resistance after coalescence relative to formulations thickened with cellulosic derivatives.
Compared with fully hydrolysed grades having saponification above 98 mol%, GOHSENX K-434 dissolves at 70–80 °C rather than 90–95 °C because the residual acetate groups disrupt interchain hydrogen bonding. The lower crystallinity reduces equilibrium moisture sensitivity and increases oxygen permeability in dry film: oxygen transmission values for partially hydrolysed PVOH films generally exceed those of fully hydrolysed films by one order of magnitude at 0 % RH when tested by ASTM D3985. Tensile behaviour is also shifted; films cast from 10% aqueous solution and conditioned at 23 °C/50 % RH typically show elongation at break of 150–250% by ASTM D882, with tensile strength in the range 40–70 MPa. The high DP near 2400 increases solution viscosity and film toughness relative to DP 500–700 grades, which commonly show viscosity below 10 mPa·s and lower tensile strength at equivalent thickness.
| Grade class | 4% aqueous viscosity at 20 °C | Saponification degree | Solution preparation temperature | Primary processing difference |
|---|---|---|---|---|
| GOHSENX K-434 | 48.0–58.0 mPa·s | 87.0–89.0 mol% | 70–80 °C | high cohesive strength, high-shear viscosity control |
| Low-DP partially hydrolysed PVOH | 5–10 mPa·s | 86.0–89.0 mol% | 60–70 °C | lower viscosity, reduced film toughness |
| Fully hydrolysed high-DP PVOH | 40–70 mPa·s | ≥ 98.0 mol% | 90–95 °C | higher oxygen barrier, higher dissolution temperature |
The residual acetate content also changes water resistance. Fully hydrolysed PVOH films dissolve only near boiling water or under intense agitation, whereas partially hydrolysed grades are soluble in cold-to-warm water. For temporary release films, water-soluble packaging, and repulpable paper coatings, this sensitivity is an operational advantage. For permanent water-resistant adhesives, however, K-434 should be crosslinked with glyoxal, ammonium zirconium carbonate, or a similar reactive modifier to limit wet strength loss. Borate-containing additives must be avoided because borate ions form di-diol complexes with PVOH and can gel the stock before application.
In blade-coated paper and paperboard lines running at 800–1500 m/min, GOHSENX K-434 is combined with clay or calcium carbonate pigments and a co-binder such as styrene-butadiene latex. The high-shear rheology of the PVOH stock influences blade pressure and coat weight uniformity; Brookfield data at 20 °C do not fully predict behaviour at blade shear rates above 10,000 s⁻¹. Capillary rheometry or slit-die measurements are used to adjust coating solids to 55–62%. Operating limits include: do not cool the colour below 25 °C because viscosity rises and blade bleeding becomes irregular; do not exceed 60 °C because gel specks can appear. Glyoxal or ammonium zirconium carbonate may be evaluated for water-resistant barrier papers, but their reaction rate with hydroxyl groups should be controlled to avoid viscosity climb in the run tank. Compliance for food-contact use must be verified against the supplier’s latest EU 10/2011 declaration, and residual methanol or acetic acid should be monitored to satisfy migration limits under the relevant end-use standard.
