GOHSENOL EG-40C

GOHSENOL EG-40C is a partially saponified poly(vinyl alcohol) resin with a nominal 4% aqueous solution viscosity of 40 mPa·s at 20°C and a degree of hydrolysis of 86.5–89.0 mol% when tested according to JIS K6726. The following application scenarios are restricted to manufacturing segments where partial hydrolysis and medium-viscosity solution rheology provide measurable process function: emulsion polymerization, paper surface sizing, textile warp sizing, ceramic tape casting, remoistenable adhesives, and solution-cast water-soluble film.

What Changes in Emulsion Viscosity and Coagulum Occur When the Protective Colloid Feed Is Held Above 90°C During VAE Polymerization?

GOHSENOL EG-40C is dissolved in demineralized water at 85–95°C under low-shear agitation until a clear solution with gel specks below 0.1 wt% is obtained, then cooled to 30–40°C before transfer to the reactor feed system. In continuous vinyl acetate-ethylene emulsion polymerization, the protective colloid solution is metered into the pre-emulsion and monomer feed at a combined rate of 3.5–7.0 wt% of total monomer feed. The reactor train comprises a high-pressure stirred CSTR with an external recirculation loop, pitched-blade or anchor impeller, and jacket cooling sized for exotherm removal at 40–60 bar ethylene partial pressure and 80–85°C polymerization temperature. At colloid dosing below 3.5 wt%, particle coalescence produces coil and heat-exchanger coagulum within 12–18 h of continuous operation. Above 7.0 wt%, final dispersion viscosity rises to 8,000–12,000 mPa·s at 25°C under ISO 2555 spindle 5 at 20 min⁻¹, causing pressure fluctuation across 80-mesh discharge filtration and unstable stripping-column feed.

The 86.5–89.0 mol% hydrolysis window of EG-40C provides a controlled concentration of acetate groups for graft reaction with vinyl acetate radicals during polymerization. The resulting graft copolymers orient at the droplet interface and suppress irreversible coalescence without requiring anionic surfactants. Particle size distribution in finished dispersions remains between 1.0 μm and 3.5 μm when the colloid solution is cooled below 40°C prior to addition. If the solution is introduced above 40°C, localized thermal destabilization of seed particles broadens the particle size distribution and increases 400-mesh residue by a factor of 2–3 over the same reactor residence time. pH is maintained between 3.8 and 5.5; amine-based coalescent additives or ammonia neutralizers above 0.1 wt% raise pH and promote deacetylation of the colloid at reactor temperature, which reduces steric stabilization and increases wall fouling. Residual vinyl acetate is stripped in a vacuum column to below 1,000 mg/kg before final viscosity adjustment.

Compliance for emulsion products depends on the finished adhesive or binder market. Food-contact adhesives are assessed under FDA 21 CFR 175.105; paper and paperboard components under FDA 21 CFR 176.170 and FDA 21 CFR 176.180. EU/EEA supply requires registration under REACH (EC) 1907/2006 and SVHC content below 0.1 wt%. Emulsion solids are controlled per ISO 3251, Brookfield viscosity per ISO 2555, and particle size distribution by laser diffraction per ISO 13320. Terminal dispersion products include wood assembly PVAc adhesives, paper-laminating adhesives, bookbinding adhesives, carpet-backing compounds, and construction emulsions.

In surface sizing of uncoated fine paper and board, GOHSENOL EG-40C is introduced as an auxiliary binder in oxidized starch solutions at 5–15 dry parts per 100 parts total size solids. The metered size press or film press is operated at 6–10 wt% size solids, 60–70°C bath temperature, and 20–80 mPa·s application viscosity at 60°C. Dry pick-up is controlled at 0.3–0.8 g/m² per side. After size application, after-dryer sections run at 120–130°C surface temperature to remove water without skinning the starch-PVA film. Inline filtration through 100-μm screens is required to remove gel particles arising from humectant or salt contamination. The sizing operation improves surface strength, reduces picking during offset lithography, and narrows ink bleed variability on commercial inkjet papers.

Terminal paper and board products include offset printing papers, inkjet commercial papers, folding boxboard, and release base papers. The operational boundary for high-speed converting is the solution gel point at low shear: once size viscosity exceeds 80 mPa·s at 60°C, film splitting and misting at the size press increase, and the bath must be diluted or the EG-40C portion reduced.

Slasher Sizing of Polyester/Cotton Warp Yarns with Medium-Viscosity Partially Saponified Poly(vinyl alcohol)

EG-40C is combined with thin-boiling starch, acrylic co-binder, and wax lubricant at 35–55 dry parts per 100 parts total size solids. Slasher trough solids are maintained at 8–12 wt%, bath temperature at 80–85°C, and application viscosity at 40–60 mPa·s at 85°C. Squeeze roll pressure is set between 20 kN/m and 40 kN/m depending on yarn count; dry add-on target is 8–11 wt% on dry warp yarn. Drying cylinder temperatures are zoned from 110°C to 135°C to prevent surface skinning and preserve film flexibility. Warp lines run at 60–100 m/min for fine-count ring-spun yarns; coarser yarns require lower speed to complete size film coalescence. Textile chemical residue compliance is assessed under OEKO-TEX Standard 100 Annex 4, and restricted substance controls follow ZDHC MRSL 3.1. The sized warp beam is conditioned at 20–23°C and 65–68% RH before loom placement because film embrittlement occurs below 12% moisture. Terminal fabrics include workwear, shirting, home textiles, and automotive seat back liners.

Ball-milled aqueous slurries for alumina and zirconia multilayer ceramic tape casting require a pyrolytically clean temporary binder that decomposes below 600°C in air without leaving alkaline residues. GOHSENOL EG-40C is introduced at 1.5–3.5 wt% based on dry ceramic powder after the slurry has reached a particle size distribution of D50 ≤ 1.5 μm. The slurry is processed in a planetary mill or recirculating bead mill at 25–35°C for 12–24 h, followed by vacuum deairing at 50–100 Pa to remove entrained voids. Tape casting onto a silicone-coated Mylar carrier uses a doctor blade gap of 0.3–0.8 mm and carrier speed of 0.3–1.0 m/min, yielding green tape thickness between 0.05 mm and 0.15 mm after drying. Debinding follows a staged profile of 2°C/min to 250°C, 2 h hold, then 1°C/min to 500°C, 1 h hold, before sintering. Residual ash from the binder must remain below 0.1 wt% to avoid shifting sintering shrinkage; incoming EG-40C lot ash is verified per JIS K6726. Process controls are maintained under ISO 9001:2015; finished substrates for electronic applications are tested per IPC-TM-650 2.5.5.2 where dielectric properties are relevant. Terminal products include multilayer ceramic capacitors, alumina substrates, oxygen sensors, and solid oxide fuel cell electrolytes.

When Dextrin/EG-40C Gumming Solutions Are Applied by High-Speed Roller Coater for Remoistenable Envelope and Stamp Adhesives

Remoistenable front-sealing gum is formulated with EG-40C at 20–40 dry parts per 100 parts of low-DE dextrin, plus plasticizer and anti-blocking agent, then processed as an aqueous solution at 40–50 wt% solids. The gumming station uses a reverse-gravure or three-roll offset coater running at 150–300 m/min; dry coating weight is maintained at 5–12 g/m². Drying uses high-velocity air at 80–100°C, followed by moisture reconditioning to prevent film curling. Activation on automated mailing lines requires rewetting with water at 15–25°C under compression of 0.2–0.5 N/mm². Food-contact adhesive status is assessed under FDA 21 CFR 175.105; EU food-contact materials are evaluated under EC 1935/2004 with migration testing per EN 1186. Terminal products include envelopes, stamps, labels, and window patch gumming. At EG-40C addition above 40 parts, high-speed inserter tack increases blocking during humid storage above 60% RH; anti-blocking talc or release-coated stacking is required.

Solution-Cast Water-Soluble Film Drying and Release Characteristics in Mold Releasing and Transfer Backing

Solution casting of EG-40C at 15–25 wt% aqueous solids with plasticizer at 5–15 parts per 100 parts poly(vinyl alcohol), using glycerol or sorbitol, produces water-soluble transfer film without the thermoforming step used for rapid-dissolve detergent capsules. The solution is deaerated and fed through a slot die onto a chrome-plated belt or release paper; drying occurs in multi-zone air flotation dryers at 60–85°C. Film thickness is controlled between 20 μm and 60 μm, and residual moisture is conditioned to 8–12 wt% before winding. At 20 wt% solids, solution viscosity exceeds 10,000 mPa·s, requiring vacuum deaeration and positive-displacement feed. Film dissolution in cold water is governed by hydrolysis degree and plasticizer level. Terminal products include embroidery support films, water-soluble splicing tape for paper machine tail threading, temporary release sheets for prepreg layup, and mold release interleaves for composite lamination. Compliance for textile transfer backings follows OEKO-TEX Standard 100 Annex 4; biodegradability screening for water-soluble packaging components may use OECD 301B or ISO 14851. Winding and storage must be conducted below 65% RH because film tackiness increases above this threshold and interleaving or climate-controlled slitting is required.