| HS Code | 876405 |
| Product | PVOH 735 |
| Chemical Type | Partially hydrolyzed polyvinyl alcohol |
| Cas Number | 9002-89-5 |
| Chemical Formula | (C2H4O)n |
| Appearance | White to cream granular powder |
| Form | Free-flowing powder or granules |
| Solubility | Soluble in hot water; practically insoluble in organic solvents |
| Viscosity 4 Solution At 20c | 28.0 - 32.0 mPa·s (cP) |
| Degree Of Hydrolysis | 87.0 - 89.0 mol % |
| Ph Of 4 Solution | 5.0 - 7.0 |
| Ash Content | ≤ 0.5 wt % |
| Volatile Content | ≤ 4.0 wt % |
| Specific Gravity | 1.19 - 1.31 |
As an accredited PVOH 735 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | PVOH 735 is supplied in 25 kg multi-wall paper bags with polyethylene liners, palletized and shrink-wrapped for safe transport. |
| Container Loading (20′ FCL) | 20′ FCL: one container, palletized PVOH 735 bags, properly secured and ventilated for safe chemical transport. |
| Shipping | PVOH 735 is shipped as a non-hazardous, water-soluble polymer powder in sealed multi-layer paper bags or drums. Protect from moisture, direct sunlight, and extreme temperatures during transit. Keep dry and well-ventilated, avoid dust accumulation, and handle with standard industrial hygiene practices. |
| Storage | Store PVOH 735 in a cool, dry, well-ventilated area, away from heat, open flames, and incompatible oxidizing agents. Keep containers tightly closed and protected from moisture and humidity, as the powder is hygroscopic. Avoid direct sunlight and extreme temperatures. Use original packaging or clean, labeled containers. Follow good housekeeping practices to prevent dust accumulation and static discharge. |
| Shelf Life | Shelf life is typically 2 years from manufacture when stored sealed, cool, and dry. |
In the commercial production of suspension-grade poly(vinyl chloride) (S-PVC), the primary dispersant system governs the interfacial tension between the vinyl chloride monomer (VCM) phase and the aqueous continuous phase, directly dictating the mean particle diameter, particle size distribution (PSD) span, and internal grain porosity. PVOH 735, characterised by a degree of hydrolysis of 72–75 mol% and a 4 % aqueous solution viscosity in the range of 5.2–6.8 mPa·s at 20 °C (measured per DIN 53015 / JIS K6726 employing a Brookfield LVF spindle), functions as a high-efficiency primary dispersant. In a typical 70 m³ BUSS-type or Goodyear continuous-stirred jacketed autoclave equipped with a three-stage Pfaudler retreat-curve impeller operating at 90–120 rpm, the addition rate of PVOH 735 ranges between 0.08 and 0.15 % by mass of the VCM charge, with the precise value tuned to the target K-value (ISO 1628-2) and the required cold plasticiser absorption (CPA) of the finished resin. A secondary dispersant—often a lower-hydrolysis PVOH (55–62 mol%) or a hydroxypropyl methylcellulose (HPMC) with a methoxyl substitution of 28–30 %—is co-dosed at 0.02–0.06 phr to fine-tune the population balance of primary particle nuclei during the pressure-drop phase of conversion. The charge sequence involves pre-dissolving PVOH 735 in demineralised water at 25–40 °C under moderate agitation for 45–60 minutes, followed by charging into the reactor, adding the organic peroxide initiator (e.g., di(2-ethylhexyl) peroxydicarbonate, EHP, at 0.03–0.08 phr), then nitrogen-purging and leak-testing. Polymerisation initiates at 53–57 °C and is maintained within a ±0.5 °C narrow band by jacket cooling; deviation beyond this threshold shifts the chain-transfer kinetics and broadens the molecular weight distribution, leading to resin grains with inconsistent fusion behaviour during subsequent extrusion. Industry compliance for the residual PVOH in the final dry resin powder for food-contact applications references (EU) Regulation 10/2011 Annex I, FCM substance No. 134, where no specific migration limit applies due to the high-molecular-weight, non-migratory nature of the polymer, and FDA 21 CFR §175.300 for indirect food additives. The downstream process following blow-down of the slurry at –0.05 MPa(g) involves steam stripping of residual VCM to below 1 ppm, centrifugal dewatering through a pusher centrifuge to a moisture content of 18–22 %, and fluidised-bed drying with an inlet air temperature of 120–140 °C to a final moisture of <0.3 %. Finished products are S-PVC resin grades ranging from pipe-grade (K-67) to film-grade (K-64), where the particle morphology imparted by PVOH 735 directly influences the gelation rate on single-screw or counter-rotating twin-screw extruders with a length-to-diameter ratio of L/D 25–30.
Vinyl acetate-ethylene copolymer emulsions destined for D3-grade wood adhesives under EN 204 rely on a poly(vinyl alcohol) protective colloid to provide both colloid-chemical stability during polymerisation and thermoplasticity in the final adhesive film. When PVOH 735 is post-added or employed as the sole protective colloid in a semi-batch oxidative-reductive polymerisation at 75–82 °C, using a 0.8–1.5 % ammonium persulfate / sodium formaldehyde sulfoxylate initiator couple based on total monomer, the degree of PVOH grafting onto the poly(vinyl acetate) backbone reaches 25–40 %, as determined by Soxhlet extraction with acetone per ISO 6427. The addition level of PVOH 735 is maintained at 2.5–4.0 % by weight of the total monomer charge, with the lower bound favouring water resistance and the upper bound increasing high-shear stability under a Cowles disperser at 3 000 rpm, a critical parameter when the emulsion is later compounded with calcium carbonate filler. Reactor configuration in a 12 m³ glass-lined vessel with a two-flight anchor agitator operating at 45–60 rpm impacts batch-to-batch viscosity variance, which is kept within ±1 200 mPa·s at 23 °C (Brookfield RVT, 20 rpm) to satisfy automated metering equipment in high-speed converting lines. Post-polymerisation, the residual monomer level is reduced to <1 000 ppm via a combination of a tert-butyl hydroperoxide redox finishing step and a stripping column operated at 60 °C under reduced pressure. Formulated adhesives containing this emulsion must comply with the indirect food contact provisions of FDA 21 CFR §175.105 when used in paper sack lamination, and with EU Regulation (EC) No 1907/2006 (REACH) for monomer residuals. The terminal articles are furniture edge-banding adhesives, spiral paper tube winding compounds, and water-resistant packaging laminates.
The remoistenable adhesive layer applied to high-speed envelope converting lines demands a cold-water-soluble film former that exhibits zero blocking at 40 °C and 80 % RH in storage yet re-tackifies within 3–5 seconds upon contact with a water-wetted sponge roller. PVOH 735, dissolved in deionised water at 18–22 % solids content and applied via a multi-roll transfer coating system at a coat weight of 5–7 g/m² dry, provides an equilibrium moisture content of 5–7 % under standard atmospheric conditions (23 °C, 50 % RH), which is essential for maintaining flexibility of the adhesive film without migration into the paper substrate. The addition of 2–5 wt% (on dry PVOH) of a polyol plasticiser—such as sorbitol or solidified glycerol—lowers the film’s second-order glass transition to approximately –5 °C, preserving cold-flow characteristics necessary for rapid licking-strip activation. Viscosity of the coating compound is controlled at 1 200–2 500 mPa·s (Brookfield LV, #4, 20 rpm) to prevent ribbing defects on gravure cylinders. Production-scale coaters operating at line speeds of 200–400 m/min utilise infrared drying hoods with an air exhaust temperature of 95–110 °C to reduce moisture to <1.5 % within 2.5 seconds dwell time. Compliance for direct food contact envelopes—used for sugar sachets or instant beverage packets—requires conformity with BfR Recommendation XXI (Germany) or FDA 21 CFR §176.170, specifically the extractive limitations in distilled water and n-heptane. Test methodology for remoistenable tack is conducted according to TAPPI T 548, using a loop tack tester at a separation rate of 300 mm/min. Terminal applications include pre-gummed postal envelopes, revenue stamps, and wallpaper borders.
In spun polyester/cotton (P/C) blend warp sizing, the selection of a partially hydrolysed PVOH enables a coherent fiber-laying film with adequate cohesion for shedding-free weaving on air-jet looms, while eliminating the need for amylase-based desizing baths that add time and cost to the finishing range. PVOH 735 is cooked in a high-shear jet cooker at 120–130 °C for 20–25 minutes to a final size liquor concentration of 9–11 wt% solids, with the addition of 0.15–0.25 % (on size weight) of a polyethylene glycol-based antistatic lubricant and 0.05 % of a silicone defoamer to suppress foam in the size box. The size box must maintain a constant level and a temperature of 85–90 °C; viscosity measured with a #3 Zahn cup should remain within 12–16 seconds to ensure constant wet pick-up. In a typical slasher sizing machine with a double dip-squeeze zone, the wet pick-up is controlled at 110–130 % on yarn weight by adjusting squeeze roller pressure to 4–6 kN/m, and the yarn is dried across seven Teflon-coated cylinders at a surface temperature of 110–140 °C with a running speed of 80–110 m/min. The sized warp beam is then installed on a Dornier air-jet loom operating at 800–1 000 rpm; end breaks per 100 000 weft insertions are maintained below 2.0 during eight-hour shifts. The desizing of PVOH 735 from grey fabric is performed in a single open-width wash range with three wash boxes at 30–40 °C without enzymatic agents, achieving a starch-size-equivalent Tegewa scale rating of 4–5 after desizing, based on AATCC Test Method 97. The final textile products passing OEKO-TEX Standard 100 product class II include men’s shirting, bed linen, and uniform workwear. PVOH 735 complies with the discharge limits of the ZDHC Manufacturing Restricted Substances List (MRSL) when process water is sent to municipal treatment.
In hydrographic water transfer printing (WTP) manufacturing, the carrier film is the critical consumable that must exhibit rapid, non-curl dissolution in a water bath at 28 ± 2 °C after an activator solvent has been sprayed onto the printed ink layer. Film cast from a 6.0–8.5 % aqueous solution of PVOH 735 blended with 5–7 phr (relative to dry PVA) of glycerol and 0.2 phr of a non-ionic surfactant (e.g., ethoxylated acetylenic glycol) on a chill-roll casting line at a line speed of 1.5–3.0 m/min yields a film of 25–40 µm dry thickness with a variation below ±2 µm across a 1.2 m web width. The dissolution rate of this film in unstirred deionised water at 30 °C averages 48–55 µm/min as determined by gravimetric analysis of film strip mass loss at 10-second intervals, outperforming fully hydrolysed grades by a factor of 2.2–2.8. This dissolution differential prevents pigment ink smearing during the transfer stage and reduces the settling of PVA residue on the jig basket, a common cause of pinhole defects on high-gloss automotive interior trims. The casting dope must be filtered through a 5 µm absolute-rated cartridge filter before application to the doctor blade to remove gel imperfections that would otherwise burnish the gravure print cylinder. The final carrier film is stored at RH 45–55 % to prevent moisture-induced blocking; tensile strength at break measured per ISO 527-3 type 5 specimens is typically 35–45 MPa. Environmental compliance for the finished decorated parts (e.g., steering wheel inserts, sports helmet shells, mobile phone covers) requires adherence to RoHS Directive 2011/65/EU for the entire assembly, with no heavy-metal content introduced through the carrier film. Process water BOD from post-transfer rinsing is maintained below 450 mg/L by controlled drainage of the bath after 50–70 m² of film processed per 100 L of bath volume, preventing biological slime formation in automated lines.
For high-purity 96–99.6 % alumina substrates used in direct-bonded copper (DBC) power modules, the organic binder system in the tape casting slurry must provide sufficient green strength for laser cutting yet decompose cleanly below 450 °C without leaving carbonous residues that compromise dielectric strength. PVOH 735, pre-dissolved as a 12 wt% stock solution and added to the alumina slip at 2.5–4.0 wt% on a dry ceramic powder basis, functions as the principal binding agent alongside 1.0–1.5 wt% of a polyethylene glycol (PEG) 400 plasticizer and 0.3–0.6 wt% of an ammonium polyacrylate dispersant (e.g., Darvan C-N). A typical slurry preparation involves ball-milling the alumina powder (D50 0.4–0.7 µm) with deionised water, the dispersant, and the PVOH 735 solution in a polypropylene jar with alumina media for 18–24 hours to achieve a viscosity of 3 500–5 500 mPa·s at a shear rate of 100 s⁻¹ (ISO 3219), followed by vacuum de-airing at –0.09 MPa(g) for 30 minutes. The doctor blade casting onto a silicone-coated PET carrier is performed at a gap setting of 150–300 µm and a speed of 0.2–0.8 m/min, with a two-zone air-flotation dryer set at 60 °C and 90 °C. The critical defect during this stage is skin formation induced by rapid surface drying when the rate of water evaporation exceeds 0.15 kg/m²·min; this is mitigated by maintaining a dew point of 18–22 °C above the drying belt. The binder burnout profile for PVOH 735, established by thermogravimetric analysis (ISO 11358-1) at a ramp rate of 0.5 °C/min, reveals complete oxidative decomposition within a temperature window of 380–430 °C, with a measured residual ash content of <0.35 % (sulfated ash, ASTM D5630). The ultimate fired substrates, sintered at 1 600–1 650 °C in hydrogen/nitrogen atmosphere, must demonstrate a dielectric strength exceeding 15 kV/mm (IEC 60243-1) and a surface roughness (Ra) below 0.3 µm to ensure copper plating uniformity. Regulatory compliance under (EU) Regulation 10/2011 is not directly applicable to technical ceramics, but the final power module assembly, when used in electric vehicle inverters, must pass the biased HAST test (JESD22-A110) which certifies the absence of corrosive binder by-products.
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Model designator PVOH 735 identifies a partially hydrolyzed polyvinyl alcohol resin whose 4 % (w/w) aqueous solution dynamic viscosity spans 5.5–7.5 mPa·s (Brookfield LV, spindle No. 1, 60 rpm, 20 °C, JIS K6726). The residual acetate content, determined by saponification-back titration, ranges from 11–13.5 mol%, placing the hydrolysis degree between 86.5 and 89 mol%. This molecular architecture—substantial acetate blocks interrupting the vinyl alcohol backbone—retards intra- and inter-chain crystallisation, conferring cold-water solubility and a solution gelation temperature below 10 °C even at 15 % solids. Ash residue (as Na₂O) is held below 0.5 % (JIS K6726), while volatiles at 105 °C for 3 h rarely exceed 5 %. In granule form the bulk density approximates 0.4–0.6 g/cm³, and the material is supplied in 25 kg multi-wall paper sacks with an inner polyethylene liner. Because PVOH 735 dissolves readily in unheated water, it serves as a temporary binder, warp-sizing agent, and water-responsive film former across paper, textiles, and single-use packaging.
A continuous film prepared on a laboratory draw-down coater (wet gap 400 µm, drying at 85 °C for 6 min) yields a dry thickness of 48–52 µm. When a 20 mm × 20 mm coupon of this film is immersed in 1 L of deionised water at 20±1 °C stirred at 100 rpm, complete disintegration (no visible fragments retained on a 2 mm sieve) occurs inside 45–60 s. This rapid dissolution, coupled with the absence of toxic monomers, meets the disintegration criterion of ISO 16929:2021 for compostable plastics but is measured here in a simplified immersion test that isolates hydrodynamic shearing from biological action. At water temperatures below 10 °C, dissolution decelerates markedly—residual film fragments persist beyond 120 s—because the polymer-solvent interaction parameter shifts closer to a theta condition as the lower critical solution temperature is approached. In industrial converting, this behaviour governs machine runnability: on a Faustel® pilot coater-laminator running at 150 m/min, an inline remoistenable glue seam based on PVOH 735 dried within 2 s of contact with a cold-water mist, whereas fully hydrolysed PVOH 117 required a 78 °C heated nip roll to achieve comparable tack development.
In the preparation of aqueous paper-laminating adhesives, PVOH 735 is added through a high-speed disperser (DINO C 1520, 7.5 kW, 400-L vessel) to deionised water preheated to 25 °C while the saw-tooth disc operates at 1200 rpm. Powder is sifted through a 500 µm inline sieve to eliminate fish-eye agglomerates. Once the target solids of 12±0.5 % is reached, the batch is stirred at reduced speed (300 rpm) for an additional 30 min under vacuum (−0.8 bar) to deaerate. Viscosity, measured with a Brookfield DV2T LV spindle No. 2 at 30 rpm, typically reads 1800–2200 mPa·s immediately after makeup and drifts less than 7 % over 24 h when stored at 23 °C in a closed container. The low ash content suppresses unwanted ionic interactions with cationic wet-strength resins such as polyamide-epichlorohydrin (PAE), a frequent partner in paperboard laminates. Production-scale experience on a 2000 t/year adhesive line indicates that substituting PVOH 735 for a higher-viscosity grade (4 % viscosity 28–34 mPa·s) reduces coating weight by 12–15 % while maintaining identical T-peel adhesion values on corrugated medium (tested per TAPPI T 838).
In contrast, when PVOH 735 is formulated with filler clay slurries for pigmented paper coatings, the system must be augmented with a high-solids latex binder; the polyvinyl alcohol alone at 2.5 phr raises low-shear viscosity too little to control blade pressure on a flooded-nip coater, whereas PVOH 705 with its 3.0–3.8 mPa·s viscosity allows a coating colour solids of 65 % without exceeding a Brookfield viscosity of 1400 mPa·s. The choice between the two grades therefore hinges on the balance between required film integrity and runnability at high solids.
PVOH 735 can be melt-processed only when plasticised. A typical formulation contains 25 phr glycerol, 10 phr sorbitol, and 0.3 phr processing aid (stearamide). Prior to feeding the co-rotating twin-screw extruder (Coperion ZSK 26 Mc18, 26 mm screw diameter, L/D 44, segmented screw with two kneading blocks at 90° offset), the granular PVOH 735 must be dried in a desiccant-bed dryer at 80 °C for 3–4 h to a residual moisture below 0.15 % (Karl Fischer titration). Feeding moisture-rich granules into the extruder causes drastic melt fracture at the die lip, visible as microscopic shark-skin, because steam generation in the metering zone (180–195 °C) leads to localised expansion and tearing. The stable processing window is narrow: barrel temperatures from the feed throat to the die must profile 140–170–185–190 °C; exceeding 205 °C at any zone induces acetaldehyde and crotonaldehyde release from thermal dehydration of residual acetate and hydroxyl groups, causing yellow-brown discolouration and an objectionable odour. Torque typically runs 55–65 % of maximum drive load (9.2 kW motor). The strand pelletised compound exhibits a MFI of 8–14 g/10 min (190 °C/2.16 kg, ASTM D1238-20) and can be injection-moulded using a clamp force of 800 kN and a cold mould at 15 °C. Publications from polymer processing laboratories caution against the use of boric acid as a crosslinker in this grade because it triggers gel particles in the melt at concentrations above 0.05 %, blocking screen packs of 80 mesh. Amine-bearing additives, including certain secondary antioxidants, are similarly incompatible, accelerating chromophore formation at typical compounding residence times of 45–90 s.
When PVOH 735 is cast directly from aqueous solution onto a release liner and dried at 110 °C, the resulting film exhibits a tensile strength of 44–55 MPa and elongation at break 180–250 % at 23 °C and 50 % RH ( ASTM D882-18, 50 mm/min crosshead speed). Comparable data for fully hydrolysed PVOH 117 film reaches 70–85 MPa but with an elongation below 80 %, underlining the flexibility advantage conferred by the acetate residues.
| Property | PVOH 735 | PVOH 705 | PVOH 117 | Test method |
|---|---|---|---|---|
| 4 % aq. viscosity | 5.5–7.5 mPa·s | 3.0–3.8 mPa·s | 28–34 mPa·s | JIS K6726 |
| Hydrolysis | 86.5–89 mol% | 87–89 mol% | 98–99 mol% | JIS K6726 |
| Film tensile strength (50 % RH) | 44–55 MPa | 34–42 MPa | 70–85 MPa | ASTM D882 |
| Cold-water solubility (20 °C) 50 µm film | Full dissolution <60 s | Full dissolution <45 s | Incomplete; film swells | Visual / sieve test |
| Typical application | Remoistenable adhesives, warp sizing | High-solids paper coating binder | Barrier film, polarising sheet temporary support | — |
In nanoclay-based oxygen-barrier coatings applied to polyester film, a binder that dissolves completely at room temperature and provides sufficient film strength without raising coating colour viscosity above 300 mPa·s at 100 s⁻¹ is critical. PVOH 735 meets both conditions: a 10 % solution has a low-shear viscosity of 160–200 mPa·s, which allows montmorillonite platelet dispersion to remain aligned during slot-die coating. Substitution of fully hydrolysed grades demands heating the entire feed tank to 88–92 °C, while low-viscosity counterparts like PVOH 705 produce films that craze upon flexing. The oxygen transmission rate of a 2 µm dry coating containing 20 wt% PVOH 735 and 80 wt% surface-modified montmorillonite drops from 12 to 0.8 cm³/(m²·day·atm) at 23 °C, 0 % RH (ASTM D3985-17), confirming that the polymer’s molecular weight provides adequate binding without occluding the tortuous path. However, at 50 % RH the oxygen barrier degrades by a factor of 6–8; published data for this specific configuration under tropical conditions are limited, and end-users are advised to conduct shelf-life testing under their intended storage environment before commercial release.
Articles manufactured with PVOH 735 intended for single-use food-contact paper coatings fall under FDA 21 CFR 175.300 (resinous and polymeric coatings) and FDA 21 CFR 175.105 (adhesives), provided the finished coating weight does not exceed the good manufacturing practice limit. The grade also complies with the EU No 10/2011 plastic materials and articles regulation and has been assessed under REACH (EC 1907/2006) with a registration number for the substance Poly(vinyl alcohol) (CAS 9002-89-5). The following table summarises key regulatory touchpoints relevant to converters and compounders.
| Regulation / Standard | Application Domain | Status |
|---|---|---|
| FDA 21 CFR 175.300 | Resinous and polymeric coatings for metal, paper, and film food contact | Conforms as a component of a cured coating |
| FDA 21 CFR 175.105 | Adhesives for food-contact laminates | Conforms; may be used up to 1.5 mg/in² adhesive layer |
| EU No 10/2011 | Plastic articles intended to come into contact with food | Approved as monomer/additive with an overall migration limit of 10 mg/dm² |
| REACH (EC 1907/2006) | Chemical substance registration, evaluation | Registered; no SVHC classification |
| EN 13432:2000 | Compostable packaging | Passes disintegration test; ultimate biodegradability must be verified in the final article |
Storage of PVOH 735 in conditions where relative humidity exceeds 60 % without resealing the sack leads to moisture absorption above 6 %, causing caking in the hopper and erratic gravimetric feeding on loss-in-weight feeders. The powder is mildly irritating to the respiratory tract; occupational exposure limits are set at 5 mg/m³ (respirable fraction, ACGIH TLV). Dust extraction equipment is required during bag emptying at a rate of 2000 m³/h per station to maintain dust below 1 mg/m³.
