GOHSENOL EG-05C

In suspension polymerisation of vinyl chloride, GOHSENOL EG-05C operates as the primary droplet stabiliser for the aqueous monomer suspension loop. The grade is a low-viscosity partially alcoholyzed polyvinyl alcohol with a 4% aqueous solution viscosity of 4.8–5.8 mPa·s at 20°C and a degree of hydrolysis of 86.5–89.0 mol%. In production-scale reactors of 50–120 m³ working volume fitted with jacket cooling, reflux condenser and Pfaudler retreat-curve impellers, the dispersant solution is prepared at 1.0–3.0 wt% in deionized water at 60–80°C, cooled to 35–45°C, and metered into the aqueous phase before vinyl chloride monomer charging. Typical aqueous-phase concentrations for primary polyvinyl alcohol stabilisers in this viscosity band fall between 0.03 wt% and 0.10 wt% relative to water; the exact operating point is adjusted against impeller tip speed and condenser load rather than held fixed. Below this range, monomer droplet size distribution shifts above 150 µm and reactor wall fouling increases; above this range, PVC plasticizer absorption falls and residual monomer stripping becomes slower. The polymerisation is controlled at 52–62°C under autogenous pressure, with conversion terminated at 80–90% to limit porosity and thermal instability. The resultant PVC resin is characterised by K-value 55–68 according to ISO 1628-2, bulk density 0.48–0.62 g/mL, and plasticizer absorption 18–30 g DOP per 100 g resin according to ISO 4608. Terminal products include rigid pipe and profile compounds, vinyl flooring, and cable insulation compounds where grain morphology and dry-up rate control downstream extrusion output. Published data for EG-05C-specific droplet size distribution at a given impeller Reynolds number is limited; plant trials should be used to set the final dispersant concentration.

How Does Protective Colloid Selection Affect Coagulum Limits in Vinyl Acetate-Ethylene Reactors?

In vinyl acetate-ethylene (VAE) emulsion polymerisation, GOHSENOL EG-05C acts as protective colloid and continuous-phase viscosity regulator. The reaction is run in high-pressure stirred reactors rated for ethylene partial pressures of 20–80 bar and temperatures of 60–120°C, with initiator systems based on sodium persulfate and a reducing agent such as sodium metabisulfite. The PVA fraction is dissolved at 4–10 wt% in the aqueous feed at 70–90°C and introduced as a continuous or semi-continuous stream with vinyl acetate monomer over 3–6 hours. Protective colloid loadings from 2 wt% to 6 wt% based on vinyl acetate monomer are typical; below 2 wt% the emulsion becomes shear-unstable and coagulum retained on a 100-mesh filter can exceed 0.10 wt%, while above 6 wt% final Brookfield viscosity can rise above 8,000 mPa·s at 25°C and reduce transfer-pump efficiency. The low solution viscosity of this grade permits final solids contents of 55–65 wt% without exceeding 5,000 mPa·s at 25°C, a processing window that high-DP partially hydrolysed PVA grades do not reliably maintain. Final emulsions are buffered to pH 4.0–5.5 with acetic acid or sodium acetate, tested for viscosity according to ISO 2555, and filtered through 45 µm and 100 µm bag filters. Alkaline amine additives should not be used for pH adjustment because a drift above pH 6.0 can hydrolyse residual acetate groups and increase coagulum. Terminal products include structural wood adhesives formulated to EN 204/205 D3/D4, paper-to-paper laminating adhesives for food packaging under FDA 21 CFR 175.105, and nonwoven binders for air-laid disposable textiles. Published data for EG-05C-specific coagulum response to ethylene pressure is limited; the loadings above are operating ranges reported for low-DP partially hydrolysed protective colloids in VAE processes.

Paper Surface Sizing and the IGT Pick Resistance Window

When GOHSENOL EG-05C is combined with oxidised starch in an inclined-jet or rod-metering size press, the PVA is pre-dispersed at 5–10 wt% in water at 80–90°C and then dosed into the starch solution to give a size press working concentration of 1.0–3.0 wt% PVA and 5–12 wt% starch dry solids. The size press is operated at sheet speeds of 100–300 m/min, wet film pick-up of 100–250 g/m², and after-dryer temperatures of 90–120°C. The dried PVA-starch layer increases IGT pick resistance and reduces dusting during high-speed printing; surface strength is assessed according to ISO 3783:2014 and wax pick can be cross-checked with TAPPI T 459 om-20. Board and liner produced with EG-05C-containing size remain within food-contact margins when the final dry PVA weight is below 3 g/m², because polyvinyl alcohol is covered by FDA 21 CFR 176.170 as a sizing and co-binder component. Terminal papers include recycled white-top liner, folding carton board and release base paper where linting must be controlled at press speeds above 12,000 sheets/hour. Over-dosing of PVA above 3 wt% in the working solution should be avoided when the furnish contains high calcium carbonate filler, because the stiffened surface can crack during folding; published data for EG-05C-specific crack resistance in this configuration is limited.

For remoistenable adhesive coating on machine-finished kraft and envelope stock, GOHSENOL EG-05C is dissolved at 15–30 wt% in deionized water at 60–80°C and applied by slot-die or reverse-roll coater at 15–35 g/m² dry coat weight. The coating line is run at 50–150 m/min with three-zone drying at 60–110°C and final web moisture held at 3–5% to prevent blocking in mill rolls. Because the grade has a 4% solution viscosity of 4.8–5.8 mPa·s at 20°C, a 25 wt% solution remains below 10,000 mPa·s at 60°C, permitting high-solids application without slot-die streak defects. Glycerol or sorbitol plasticiser is introduced at 3–10 wt% of PVA to reduce film brittleness after drying. The remoistening bond of the finished tape is evaluated by 180° peel adhesion under ISO 29862:2018 if the tape construction is within scope; blocking resistance is checked by a constant-load method after storage at 40°C/90% RH for 24 hours. Terminal products include gummed paper tape, envelope flaps, label stock and tamper-evident seals. Compliance with food-contact adhesive requirements is maintained under FDA 21 CFR 175.105; any finished package used for direct food contact must be revalidated at the converter level because the adhesive is only one component of the final laminate. Published data for EG-05C-specific peel strength on kraft substrates is limited.

When Ceramic Tape Casting Slurries Require Binder Burnout Below 500°C

Low-viscosity partially hydrolysed PVA is used in water-based ceramic tape casting because the polymer can be dissolved at 5–10 wt% in deionized water and incorporated into alumina, zirconia or barium titanate slurries at 1–3 wt% based on ceramic solids. The slurry is prepared by dispersing ceramic powder with an ammonium polyacrylate dispersant at 0.3–0.8 wt% on solids, adding the GOHSENOL EG-05C solution, and plasticising with glycerol or PEG 400 at 10–30 wt% of PVA. The slurry is de-aired under vacuum at 50–100 mbar and cast through a doctor blade with a gap setting of 100–500 µm onto a polyester carrier at 500–2,000 mm/min. Drying at 25–60°C leaves a flexible green tape with residual moisture below 1.5 wt%. Binder burnout is conducted in air at 350–550°C with a heating ramp of 0.5–1.5°C/min to prevent carbon residue; decomposition is monitored by thermogravimetric analysis according to ASTM E1131-20. Terminal components include LTCC substrate tapes, multilayer ceramic capacitors and piezoceramic elements where the green tape must maintain thickness tolerance of ±2–5 µm before lamination and sintering. If the binder system is exposed to amine-containing dispersants at pH above 9, premature hydrolysis can reduce green tape elongation; published data for EG-05C-specific green tape elongation in this configuration is limited.

On high-speed slasher frames configured with 12-cylinder drying hoods and dual squeeze roll size boxes, GOHSENOL EG-05C is applied to polyester-cotton warps as part of an 8–12 wt% size solution at 70–90°C. Dry add-on is controlled at 8–14 wt% on yarn mass, with squeeze pressure set between 20 N/mm and 40 N/mm and drying cylinder temperatures staged from 90–130°C. The partially hydrolysed PVA film remains abrasion-resistant at loom speeds above 1,500 m/min, reducing warp yarn hairiness as measured on an Uster Tester 5 at 400 m/min and lowering shedding in the weaving shed. Desizing is carried out without enzymes in hot water at 80–95°C for 20–30 minutes, which removes the PVA film from greige fabric and permits size recovery by ultrafiltration; this is an operational boundary when the weaver requires zero formaldehyde and APEO-free processing. Terminal products include woven apparel fabric, furnishing fabric and automotive airbag base cloth where a clean, insoluble-residue-free warp size is required. Compliance with ZDHC MRSL and REACH Annex XVII is demonstrated through the absence of intentionally added alkylphenol ethoxylates; however, final fabric certification must be revalidated at the finishing mill. Published data for EG-05C-specific weaving efficiency on air-jet looms is limited.