| HS Code | 848835 |
| Chemical Name | Polyvinyl alcohol |
| Cas Number | 9002-89-5 |
| Appearance | White granular powder |
| Degree Of Saponification Mol Percent | 80.0 ± 1.0 |
| Viscosity 4 Percent Solution At 20c Mpa S | 5.0 ± 0.5 |
| Ph Of 4 Percent Solution | 5.0 - 7.0 |
| Volatile Content Percent | ≤ 5.0 |
| Ash Content Percent | ≤ 0.5 |
| Density G Cm3 | 1.27 |
| Bulk Density G Cm3 | 0.4 - 0.5 |
| Solubility | Soluble in water; practically insoluble in organic solvents |
As an accredited GOHSENOL C-500 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | GOHSENOL C-500 is packed in 25 kg multi-wall paper bags with an inner plastic liner for secure handling and storage. |
| Container Loading (20′ FCL) | GOHSENOL C-500 is loaded as a 20′ FCL in 25 kg bags on pallets, securely shrink-wrapped for safe, dry transport. |
| Shipping | GOHSENOL C-500 is a polyvinyl alcohol powder shipped in paper or woven bags with a PE liner. Protect from moisture, rain, and mechanical damage during transport. Keep away from ignition sources and incompatible materials. Store in a cool, dry area and handle with care to avoid dust generation. |
| Storage | Store GOHSENOL C-500 in a cool, dry, well-ventilated area, keeping the container tightly sealed to prevent moisture absorption and contamination. Protect from direct sunlight, heat, and open flames. Avoid generating dust and keep away from incompatible materials. Under proper conditions, the product remains stable for an extended period. |
| Shelf Life | Shelf life: 2 years from manufacture if stored sealed, cool, and dry. Avoid moisture and extreme heat. |
GOHSENOL C-500 is a fully hydrolyzed polyvinyl alcohol resin with a degree of hydrolysis between 98.0 and 99.0 mol% and a 4 % aqueous solution viscosity of 4.8–5.8 mPa·s at 20 °C. The grade is supplied as a white granular powder with ash content no greater than 0.5 % and volatile content no greater than 5.0 %. These parameters place C-500 in the medium-viscosity, fully hydrolyzed segment of the GOHSENOL range, where high film tensile strength, oil resistance, low-foam dissolution, and shear stability are required. The following application routes are limited to established industrial conversions in which C-500 functions as a protective colloid, binder, surface size, or temporary barrier film former.
In continuous and semi-continuous vinyl acetate-ethylene emulsion polymerization, GOHSENOL C-500 is introduced as a pre-dissolved 8–10 % aqueous solution into the pre-emulsion feed line. Dosage is calculated against total vinyl acetate monomer mass. At 2.0–6.0 wt%, the fully hydrolyzed PVOH forms a grafted protective layer around the vinyl acetate-ethylene copolymer particles during nucleation and growth. Production-scale observations on a 20 m³ stirred tank reactor equipped with a radial flow impeller, internal cooling coil, and external plate heat exchanger indicate that C-500 concentration governs median particle size, final dispersion viscosity, and coagulum formation. When the dosage falls below 2.0 wt%, wet-screen coagulum typically exceeds 0.15 % because surface coverage at the particle-water interface becomes insufficient. At dosages above 6.0 wt%, the final dispersion viscosity may rise beyond 15 000 mPa·s at 25 °C, limiting heat removal through the external loop and extending the post-polymerization hold period. The preferred production window for a 50–55 % solids VAE dispersion is 3.5–4.5 wt% C-500 based on vinyl acetate monomer.
The dissolution protocol for reactor feed requires C-500 to be hydrated at 85–90 °C for 45–60 min under low-shear agitation. Air entrainment during dissolution is controlled by maintaining the agitator below 120 rpm in a baffled tank. The solution is cooled to 40–50 °C before being metered into the pre-emulsion vessel. The reaction mass is held at 80–90 °C under an ethylene partial pressure of 20–45 bar, with ethylene distributed through a sparge ring into the liquid monomer phase. A separate redox initiator feed, normally persulfate/bisulfite, is used because direct premixing with the PVOH solution can generate radical transfer sites and premature color development.
Compliance documentation for emulsions stabilized with C-500 references EU REACH EC 1907/2006, GB 18583-2008 for volatile organic compound limits in Chinese adhesive markets, and US FDA 21 CFR 175.105 when the resulting dispersion is used in food-contact laminating adhesives. Finished emulsions are screened through a 250 µm stainless steel filter basket before drumming. The final pH is typically buffered to 4.0–5.5 with sodium acetate. The table below summarizes representative production-scale ranges for a VAE dispersion stabilized with C-500.
| Protective colloid dosage on vinyl acetate monomer | Median particle size | Dispersion viscosity at 25 °C | Wet-screen coagulum |
|---|---|---|---|
| 2.0 wt% | 1.5–2.5 µm | 1 000–3 000 mPa·s | 0.08–0.20 % |
| 4.0 wt% | 0.8–1.8 µm | 4 000–8 000 mPa·s | 0.02–0.08 % |
| 6.0 wt% | 0.5–1.2 µm | 9 000–14 000 mPa·s | <0.02 % |
The terminal emulsions are converted into water-based wood assembly adhesives, single-component construction adhesives, paper and board laminating adhesives, and nonwoven binder systems. A formulation boundary exists at low plasticizer content: the fully hydrolyzed PVOH shell raises minimum film formation temperature relative to partially hydrolyzed alternatives, which can reduce cold-temperature film coalescence in exterior wood adhesives.
Surface sizing of uncoated woodfree paper with GOHSENOL C-500 is specified when the mill requires oil holdout, surface strength, and lint resistance beyond the performance of oxidized starch alone. The size press preparation follows a two-kitchen sequence. C-500 is first dissolved in a jacketed dissolver at 8–12 % solids and 85–90 °C for 45 min. The solution is transferred to the starch holding tank and combined with enzymatically or thermally degraded cationic starch at a dry ratio of 0.5–2.0 parts PVOH per 100 parts starch. The final size press bath is held at 50–65 °C and 30–120 mPa·s, with 0.05–0.20 % of a polydimethylsiloxane defoamer where air entrainment is detected downstream of the screen. On a metering size press running at 800–1 200 m/min, the PVOH-modified formulation deposits 1.0–3.5 g/m² per side dry pickup. At higher pickup, sheet curl increases because the felt and wire sides dry unevenly across the after-drying cylinders; infrared profiling dryers are therefore positioned before the first heated can.
Quality verification uses ISO 535 Cobb60 for water absorption and ISO 3783 for IGT pick resistance. On an 80 g/m² bleached kraft base, a C-500-containing size press formulation typically yields a Cobb60 value of 20–30 g/m², compared with 30–45 g/m² for a starch-only control. IGT pick resistance shifts from <1.0 m/s to 1.8–2.5 m/s. Brightness retention is measured by ISO 2470; at a 2.0 part C-500 dosage, the brightness loss is less than 0.5 points because the resin ash content is low. Sized bases are converted into offset printing grades, high-speed inkjet papers, release liner base stock, and food-contact paperboard where the final coated sheet is assessed under EU 10/2011 for plastic materials in food contact.
On high-density weaving lines processing ring-spun cotton and polyester/cotton blends, GOHSENOL C-500 is introduced as a film-forming warp size to suppress yarn hairiness and improve abrasion resistance through the shedding zone. The size formulation is built around a C-500-to-modified starch ratio of 50:50 to 70:30 dry solids. C-500 constitutes 6–12 wt% of the total size liquor, and dry add-on is controlled at 10–15 % of warp yarn weight for plain-weave constructions above 70 ends/cm. The cooking sequence requires C-500 to be predispersed in a jet cooker at 90–95 °C for 30 min before starch addition. Adding dry C-500 directly to the size box causes lump retention on the slasher filter screens and uneven film thickness at the squeeze nip.
The slasher line is typically a multi-cylinder single-end sizing machine with a pre-wet box and a main size box. Size bath temperature is maintained at 85–95 °C, and circulation viscosity is held below 120 mPa·s. Squeeze nip pressure is set to 30–80 kN/m depending on yarn count and fiber blend. Cylinder drying temperatures must remain below 135 °C; higher surface temperatures discolour C-500 and reduce the flexibility of the deposited film. The dried warp leaves the front section at 6–8 % moisture and is separated into sheet sections ahead of the lease rods. On high-speed air-jet and rapier looms, the C-500 film reduces warp breakage per 100 000 picks from 2.5–4.0 to <1.0 on polyester/cotton shirting under identical loom speed and shed geometry.
Supply-chain compliance is documented under ZDHC MRSL v3.1 for the size formulation and OEKO-TEX Standard 100 for residual substances after desizing and bleaching. Desizing efficiency is checked by AATCC 79 absorbency; fully desized fabric should reach a wetting time below 5 s. The terminal fabric range includes high-density shirting, workwear poplin, denim warp beams, airbag base cloth, and industrial conveyor belt fabrics. The operational boundary for C-500 is cold-water removability. Because the grade is fully hydrolyzed, enzymatic or oxidative desizing at 60–85 °C is required instead of ambient wash-off, which would leave hard size residues and reduce downstream dye penetration.
Tape casting of borosilicate glass-ceramic and alumina powders for low-temperature co-fired ceramic substrates uses GOHSENOL C-500 when green-sheet tensile strength and lamination uniformity must be retained after doctor-blade forming. The binder is pre-dissolved in deionized water at 80 °C to a 10 % stock solution and introduced only after the ceramic powder has been dispersed in a water/isopropanol vehicle at 60:40 to 70:30 by volume. C-500 concentration is 1.5–3.5 wt% of dry ceramic powder. Plasticizer is added at 2.0–4.5 wt% on binder dry solids, commonly glycerol or polyethylene glycol 400, to prevent edge cracking after solvent evaporation. The slurry is milled in two stages using 3 mm yttria-stabilized zirconia media. In the first stage, ceramic powder and solvent are milled for 12–16 h with a dispersant. In the second stage, the C-500 stock solution is added at low tip speed and mixed for an additional 4–6 h. High-shear addition above 500 rpm causes air entrainment and localized binder precipitation at the slurry surface, which later appears as crater defects in the green tape.
The slurry is deaired under 50 kPa absolute pressure for 20–40 min and cast onto silicone-coated polyethylene terephthalate carrier film through a doctor blade gap of 100–300 µm. Drying is performed in a three-zone conveyor oven at 60–80 °C with laminar airflow to prevent skinning. Dry tape thickness is controlled from 50–200 µm. Binder burnout is validated by thermogravimetric analysis according to ASTM E1131-08, with plateaus at 350 °C and 550 °C. Because C-500 ash content is no greater than 0.5 %, the calculated inorganic residue from a 2.5 wt% binder dosage is below 0.01 wt% of the ceramic body. Green strength is evaluated by a 3-point bend test adapted from ISO 14704, with unfired tapes typically requiring failure stress above 1.2 MPa before lamination onto via-punched layers.
The cast green sheets are used for multilayer ceramic capacitor dielectric builds, LTCC radio-frequency substrates, ceramic filter blanks, and piezoelectric actuator layers. A production limitation is the low cold-water solubility of C-500. Cleaning of doctor blades, casting heads, and downstream tooling requires hot water above 70 °C; dried binder deposits released as hard particles during subsequent casting runs will produce surface defects in the sintered part.
For closed-mold composite tooling where silicone contamination must be excluded, GOHSENOL C-500 is applied as a temporary release film on gel-coated molds. The release solution is prepared at 5.0–8.0 wt% PVOH, with 5–15 wt% polyethylene glycol 400 on PVOH solids as flexibilizer and 0.05–0.20 wt% of a silicone-free defoamer. Application is performed by low-pressure spray or short-nap roller onto a mold surface that has been pretreated with a sealing release wax. The wet film is deposited in two passes to reach 100–200 µm wet thickness, yielding a dry film of 20–50 µm. Drying takes place at 50–70 °C for 30–90 min depending on ambient relative humidity. The dried film is inspected for pinholes before laminate layup because defects in the PVOH barrier permit epoxy or unsaturated polyester resin contact with the tool surface, causing localized bonding and part release failure.
The cured composite is demolded by immersion or water-jet spraying at 60–80 °C under 0.2–0.5 MPa. The C-500 film dissolves in 5–15 min on closed contours and leaves no silicone residue on the composite or the tool. This is significant for subsequent adhesive bonding or painting, where silicone transfer reduces lap-shear strength. Compliance documentation for the release film references EU RoHS Directive 2011/65/EU where the final composite component enters regulated electrical and electronic equipment. The release film is a process consumable, not a finished article, and no food-contact status is claimed for this route. Terminal products include carbon fiber tubes, wind turbine blade spar caps, glass-reinforced polyester hulls, and compression-molded automotive components.
A processing boundary exists at low demolding temperatures. C-500 releases slowly below 50 °C, and ambient-water demolding is not recommended. For molds with significant undercuts, the film is built in three layers to prevent tearing during resin flow. Crosslinking should be avoided because borate or aldehyde treatment extends dissolution time beyond 30 min and can leave insoluble PVOH residues in sharp tooling radii.
Remoistenable adhesive converting for envelope flaps, labels, and stamps uses GOHSENOL C-500 as a high-strength replacement for dextrin when low dusting and rapid water activation are required after drying. The resin is dissolved at 20–35 % solids in a high-torque dissolver at 85–90 °C. In the finished adhesive, C-500 constitutes 40–70 wt% of dry adhesive solids. Plasticizer, normally glycerol or sorbitol, is added at 5–15 wt% on PVOH solids to reduce film embrittlement after drying. A wax or calcium stearate dispersion at 2–8 wt% on dry solids is incorporated to control blocking under high-humidity storage. The coating is applied by direct gravure or reverse roll to the envelope flap or label face at 20–35 g/m² wet film weight. Drying is conducted in a high-velocity air oven at 60–90 °C for 5–15 s, leaving a non-tacky dry adhesive that activates after 1–5 s of water contact.
Blocking resistance is evaluated at 40 °C and 80 % relative humidity for 24 h, with a pass criterion of no fiber tear when stacked coated blanks are separated. Remoistening adhesion is tested by a 180° peel method adapted from ASTM D3330 on coated paper under 20 s dwell after water application. Coated stock is considered acceptable when fiber tear exceeds 90 % of the bonded area. Where the finished adhesive may contact food-packaging board, the formulation is documented under US FDA 21 CFR 175.105. For European paper and board converters, the adhesive is supplied with a REACH compliance declaration under EC 1907/2006. Terminal products include lick-and-stick envelopes, stamp face paper, label facing stock, and pre-pasted wallcoverings.
The operational boundary for C-500 is storage humidity. Uncoated powder must be kept below 60 % RH and predried at 60 °C for 2 h if exposed to moisture, because free moisture changes dissolution time and may form lumps in the high-solids dissolver. Cold-water activation of the fully hydrolyzed grade is slower than that of partially hydrolyzed PVOH. Sorbitol can be used at 5–10 wt% on PVOH solids to improve activation, but sorbitol concentrations above 15 wt% reduce dried-film antiblocking performance and increase calender pickup on the converting line.
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GOHSENOL C-500 is a fully hydrolysed polyvinyl alcohol grade in the GOHSENOL product family, supplied by Mitsubishi Chemical Corporation. Product documentation identifies C-500 as a medium-viscosity, low-ash material with a hydrolysis specification of 98.0–99.0 mol%, determined according to JIS K6726. The delivered material is white to pale yellow in powder or granular form, with volatile matter controlled at ≤ 5.0% and ash as Na2O controlled at ≤ 0.5%. The 4% aqueous solution viscosity at 20 °C is specified as 25.0–30.0 mPa·s, and the pH of that solution is typically 5.0–7.0. These boundaries place C-500 in the fully saponified, medium-molecular-weight segment; the product is not equivalent to cold-water-soluble partially hydrolysed grades. The principal difference between C-500 and lower-hydrolysis GOHSENOL grades is the temperature at which a clear solution can be obtained. Partially hydrolysed grades dissolve in cold water, but C-500 does not. Therefore C-500 should be selected when the final article must withstand wet handling or when the process already has heated mix tanks; it should not be specified for ambient-temperature dissolution operations.
The high hydrolysis specification leaves only 1.0–2.0 mol% residual acetyl groups on the polymer chain. This increases intermolecular hydrogen bonding and crystallite density, so C-500 does not dissolve at ambient temperature. Aqueous dissolution proceeds only after the polymer is heated sufficiently to disrupt crystalline regions; the practical dissolution window in agitated water is 85–95 °C. Below 85 °C the polymer can swell into gelatinous aggregates but remains incompletely dissolved, while above 95 °C evaporation and viscosity drift become more pronounced. The same crystallite structure gives dried C-500 films higher moisture resistance and greater tensile stiffness than partially hydrolysed grades in the 86.0–89.0 mol% range. This is why the product is selected for surface sizing and warp sizing rather than for cold-water-soluble packaging film. The hydrolysis value is measured by saponification titrimetry under JIS K6726; it is a release property, not a derived value from viscosity.
In production-scale dissolution, the preferred practice is to pre-slurry C-500 powder in ambient water at 20–30 °C before transferring the slurry to a jacketed vessel equipped with a low-shear anchor or pitched-blade turbine and baffles. The vessel is then heated to 85–95 °C and held at that temperature until the solution is clear and free of visible gel particles. Direct addition of powder to hot water is a known failure mode: the surface of the granule hydrates rapidly and forms a gel skin that seals dry polymer inside, producing lumps that are difficult to disperse in standard side-entry mixers. Batch concentration for paper applications is commonly 8–12 wt%; for adhesive compounding, 15–20 wt% solutions are practicable, but viscosity climbs steeply above 20 wt% and pump cavitation may occur in unpressurized transfer lines. Because C-500 is a polyol, borate ions and certain polyvalent metal salts can form reversible or irreversible complexes. Borax must be added only in controlled amounts if structured viscosity is intended; uncontrolled borate addition can crosslink the polymer and produce a gel that cannot be pumped.
The solution viscosity specification is the primary batch-release proxy for degree of polymerisation. A 4% aqueous solution is prepared and conditioned at 20 °C, then measured on a rotational viscometer according to JIS K6726. The accepted range of 25.0–30.0 mPa·s is relatively narrow; this matters when C-500 is blended with starch because starch/PVOH size viscosity is sensitive to both polymer ratio and temperature. The ash limit of ≤ 0.5% is equally important for applications where sodium residues create deposits in sizing equipment or interfere with paper surface properties. Table 1 summarises the manufacturer's standard specification profile; users should request the certificate of analysis for each lot because distribution conditions and packaging can affect moisture content.
| Parameter | Test method | Specification |
|---|---|---|
| Appearance | JIS K6726 | White to pale yellow powder or granule |
| Volatile matter | JIS K6726 loss on drying | ≤ 5.0% |
| Ash as Na2O | JIS K6726 | ≤ 0.5% |
| Hydrolysis degree | JIS K6726 saponification | 98.0–99.0 mol% |
| Viscosity, 4% aqueous at 20 °C | JIS K6726 rotational viscometer | 25.0–30.0 mPa·s |
| pH, 4% solution | JIS K6726 | 5.0–7.0 |
Paper surface sizing with C-500 is typically carried out on puddle or film size presses, with the size liquor held at 60–80 °C to avoid gelation in the return line. The product is dissolved separately at 85–95 °C and then blended with oxidised starch or other binders. Water absorption of the sized sheet is measured as Cobb value, commonly at 60 s or 120 s contact time under ISO 535. Mill operating records indicate that replacement of 10–20 wt% of the starch solids with C-500 can increase sizing efficiency, but published data for specific base stock configurations is limited; because Cobb response depends on furnish, press solids, and calendering, a pilot coater trial is required to establish the exact add-on. The high hydrolysis range of C-500 also reduces re-wetting of the dried size film, a property that cannot be inferred from solution viscosity alone.
When a converting site moves from a partially hydrolysed polyvinyl alcohol to C-500, the first formulation variable is dissolution energy. The partially hydrolysed grade may enter solution at 10–30 °C; C-500 requires 85–95 °C and therefore cannot be dumped into a cold mix. The second variable is film performance: because C-500 has fewer residual acetyl groups, dried films are more resistant to water and less tacky in humid air, but they are also stiffer. In adhesive compounding, C-500 is used where high bond strength after drying is more important than cold tack. In textile size, C-500 replaces partially hydrolysed PVOH when loom humidity is high or when the cloth requires greater resistance to size shed. The comparative envelope in Table 2 is based on hydrolysis range; it is not a substitute for grade-specific data because viscosity and ash properties differ within each category.
| Parameter | GOHSENOL C-500 | Partially hydrolysed PVOH | Intermediate-hydrolysis PVOH |
|---|---|---|---|
| Hydrolysis degree | 98.0–99.0 mol% | 86.0–89.0 mol% | 91.0–94.0 mol% |
| Aqueous solubility | Hot water only, > 85 °C | Cold-water soluble at 10–30 °C | Warm-water soluble at 40–60 °C |
| Film water resistance | High | Low | Moderate |
| Film tensile strength | High | Moderate | Medium-high |
| Ash content | ≤ 0.5% | Grade-dependent | Grade-dependent |
On cotton and cotton/polyester warp-sizing lines, C-500 size liquor is held at 80–90 °C in the size box. The size film is typically combined with starch or acrylic binders; C-500 contributes cohesion and reduces fibre hairiness during high-speed weaving. Sized yarn tensile properties are evaluated on a constant-rate-of-extension tensile tester; laboratories frequently base conditioning on ISO 291 at 23 ± 2 °C and 50 ± 5 % RH before testing. Process staff monitor size pick-up after squeeze rolls and control add-on by adjusting solids and nip pressure rather than by relying on viscosity alone. Wax or oil-based softeners, when used, should be screened for compatibility because excessive plasticisation reduces the strength benefit of the fully hydrolysed polymer. Published loom-shedding data for C-500 in a specific warp configuration is limited; mill trials are therefore required for end-use validation.
Regulatory classification for C-500 follows the polyvinyl alcohol inventory entries in the relevant markets. Polyvinyl alcohol is a permitted component in certain paper and paperboard food-contact applications under 21 CFR 176.170, and in adhesives under 21 CFR 175.105; users must verify that C-500 is covered by the manufacturer's food-contact statement for the specific end use, packaging construction, and extraction conditions. The low ash specification of ≤ 0.5% is relevant in high-purity paper grades where extractable sodium must be minimised. In EU REACH, polymers are generally exempt from registration, but the monomer and any unreacted VAM are regulated separately; a certificate of composition from the supplier should be retained. C-500 is not a cold-water-soluble packaging grade; therefore food-contact film applications that require ambient dissolution are outside the product's practical envelope.
Solution-cast film based on C-500 is produced from a dope containing 10–20 wt% PVOH solids and 2–5 wt% plasticiser, typically glycerol or triethylene glycol, dried in a forced-air tunnel at 60–80 °C. The resulting film is not cold-water soluble; immersion in warm water causes swelling but not immediate dissolution. Tensile testing of such films is commonly carried out according to ISO 527-3 on strips conditioned at 23 ± 2 °C and 50 ± 5 % RH; the exact tensile values are formulation-dependent. This behaviour distinguishes C-500 from packaging films based on partially hydrolysed grades, which dissolve at ambient temperature but provide lower moisture resistance after drying.
Powder transfer systems for C-500 should be closed, and silos or intermediate bulk containers should be maintained below 60% RH to reduce compaction. The organic powder should be handled as a combustible dust; dust collection equipment is typically specified under NFPA 654 or local equivalent. Pre-drying before dissolution is not routinely required unless moisture ingress has caused caking; caked material should be broken before slurry preparation because wet agglomerates hydrate more slowly and extend the dissolution cycle. These handling limits are operational rather than cosmetic, since both moisture uptake and dust dispersion change the consistency of downstream dosing.
For dry-press ceramic tile and technical ceramic granulate, C-500 is used as a temporary organic binder. Binder addition of 1.0–3.0 wt% solids on dry body is a common starting point, but the exact level is set by granulate flow, press pressure, and green strength. Because the ash content is controlled to ≤ 0.5%, residual inorganic material after burnout is low enough for many oxide and silicate bodies. The pressed parts are dried at moderate temperature to prevent re-dissolving the binder with condensed moisture; storage of the dried granulate is best maintained below 60% RH because atmospheric moisture can plasticise the PVOH film and reduce flow. Published green-strength data specific to C-500 in ceramic systems is limited; therefore press settings are determined by green-packing density and fracture testing on the production line rather than by a universal standard.
