| HS Code | 571370 |
| Water Solubility | Insoluble in water |
| Tensile Strength | Moderate to high mechanical strength |
| Elongation At Break | Flexible with controlled stretchability |
| Tear Strength | Resistant to tearing and puncture |
| Optical Transparency | Clear or translucent appearance |
| Chemical Resistance | Resistant to oils, fats, and many organic solvents |
| Biodegradability | Biodegradable under specific environmental conditions |
| Oxygen Barrier | Good barrier to oxygen and gases |
| Thermal Stability | Stable across a broad temperature range |
| Moisture Sensitivity | Low water absorption due to water-insoluble formulation |
As an accredited Non Water Soluble PVA Film factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Available in 25 kg quantities, packaged in moisture-resistant sealed bags inside durable cartons, labeled for safe chemical handling. |
| Container Loading (20′ FCL) | Non-water-soluble PVA film is packed in cartons, palletized, and loaded into a 20′ FCL container, secured to prevent shifting and moisture exposure. |
| Shipping | Non Water Soluble PVA Film is shipped in sealed, moisture-resistant packaging to maintain product integrity. It is non-hazardous under standard transport conditions, requiring no special temperature controls. Use dry, covered containers or trucks to prevent humidity exposure. Ensure proper labeling and documentation in compliance with local and international shipping regulations. |
| Storage | Store Non Water Soluble PVA Film in a cool, dry, well-ventilated area away from direct sunlight and heat sources. Keep in its original sealed packaging or airtight container to prevent moisture absorption and contamination. Avoid contact with oils, solvents, and sharp objects. Maintain moderate humidity and temperature to preserve film integrity and performance. |
| Shelf Life | Store in a cool, dry place away from moisture. Shelf life is typically 12 months from manufacture. |
In autoclave and oven-cure processing of epoxy- and phenolic-based fiber-reinforced composites, non-water soluble PVA film serves as a dry peel ply that eliminates solvent-based mold release agents. The film is laid directly onto the prepreg stack prior to vacuum bagging. Film thicknesses between 25 µm and 75 µm are selected according to laminate surface profile requirements; thinner grades replicate tool face smoothness, while thicker films provide a matrix-rupture peel that creates a bondable surface for subsequent adhesive joining or painting. The PVA grade used typically incorporates a controlled degree of crosslinking to withstand cure temperatures up to 190°C without softening or adhering to the laminate. Test data per DIN 55660-2 place the critical surface tension of the non-water soluble film below 30 mN/m, responsible for the inherent release character against common resin systems. Peak exotherm during thick-section cures must be monitored with embedded thermocouples; bulk resin temperature excursions above the film’s onset-of-stick temperature—documented for some commercial grades at 200°C—produce local adhesion patches that require abrasive removal and compromise bond strength. Post-cure, the film strips cleanly, leaving a textured surface free of silicone or wax residues attributable to mold release chemistries. Aerospace repair facilities validate peel-ply performance through lap shear testing on representative coupons in accordance with ASTM D3165; values exceeding 25 MPa are routinely obtained after peel removal without additional sanding. Off-spec scenarios observed on production autoclaves include pre-release due to inadequate vacuum integrity and bag-side bridging over female corners. To mitigate, the film is intentionally perforated in staggered patterns with hole diameters between 0.5 mm and 1.2 mm at densities not exceeding 2% open area to balance resin bleed with clean release. End-part configurations include aircraft interior panels, radomes, and automotive CFRP body components where direct painting or bonding is specified without intermediate abrasion steps.
A typical laminated structure for dry-mix applications places a non-water soluble PVA core at 15–25 µm between outer layers of 12 µm polyester and 50 µm LLDPE via polyurethane adhesive applied at 2.5 g/m². Oxygen transmission measured at 23°C, 0% RH per ASTM D3985 drops to <0.2 cm³/m²·day·atm for a 20 µm PVA core. When relative humidity on both film surfaces exceeds 50%, the same structure exhibits OTR values rising above 5 cm³/m²·day·atm within hours. This binary behavior imposes strict control of internal moisture: desiccant sachets are inserted and pouch seal integrity is verified offline using vacuum dye penetration in accordance with ASTM F3039. The PVA film complies with EU Regulation 10/2011 and FDA 21 CFR 177.1670. Processing on a solventless laminator demands precise tension management because the PVA core elongates under web stress; elongation below 3% at 20 N/50 mm is targeted to prevent blocked adhesive channels. Slitting at widths down to 300 mm is performed with rotary shear knives to avoid micro-cracking at film edges that later propagate during retort. End-use pouches are employed for freeze-dried coffee, nutritional powders, and oxygen-sensitive snack inserts. The table below documents the humidity-induced step change in barrier performance for a 20 µm non-water soluble PVA monolayer.
| Relative Humidity | O&sub2; Transmission Rate (cm³/m²·day·atm) | Test Standard |
|---|---|---|
| 0% RH | 0.2 | ASTM D3985 |
| 50% RH | 1.5 | ASTM D3985 |
| 80% RH | 6.8 | ASTM D3985 |
Non-water soluble PVA film substitutes silicone-coated PET in selective heat-transfer applications where the carrier sheet is required to biodegrade after removal or where silicone contamination interferes with subsequent lacquer adhesion. The film is cast at 20–25 µm gauge with a tensile strength not lower than 55 MPa (ISO 527-3) and thermal shrinkage restricted to ≤1.5% at 190°C for 30 seconds. Prior to printing, the surface is corona-treated to 48–52 dyn/cm to anchor the water-based inkjet receiver coating. During the transfer step, the printed film is placed image-side down onto the fabric and pressed at 180–200°C under 0.4–0.6 bar for 12–15 seconds. After the dwell, the assembly is cooled to below 40°C, at which point the PVA carrier peels away with a release force of <0.05 N/25 mm, leaving the ink fully embedded in the polyester or cotton textile. The cold-peel mechanism eliminates color-matching drift caused by post-release warping. Compliance with OEKO-TEX Standard 100 (product class I) is mandatory for skin-contact garments. One processing bottleneck observed on pneumatic double-platen presses is heat dissipation across the platen edges, generating a temperature difference of 8–12°C; this requires platen-edge heater compensation to avoid incomplete transfer at the margins. Finished products range from customized performance-wear labels to full-body prints on promotional T-shirts.
PVA film with a volume resistivity consistently held between 10&sup8; Ω·cm and 10¹¹ Ω·cm at 12% RH (IEC 61340-2-3) eliminates migratory antistatic agents that contaminate sensitive bond pads. Non-water soluble grades prevent hygroscopic swelling on exposure to ambient humidity while retaining rapid charge decay below 0.5 seconds as per IEC 61340-5-1. A 50–80 µm film is heat-seal-coated on one side with a low-sealing-integrity copolyester adhesive that activates at 110–130°C; dwell time on a tray lidding machine is set between 0.8–1.2 seconds to limit static build-up from friction. Finished lidding is applied to thermoformed polystyrene or conductive ABS trays holding MOSFET, IGBT, or MEMS devices. The structure meets outgassing limits of ASTM E595 (TML <1.0%, CVCM <0.1%) for spacecraft electronics. On a packaging line, humidity control at <15% RH during film unwinding is essential; a dew-point sensor in the forming area triggers an alarm when moisture uptake raises surface resistance above 10¹² Ω/sq, a shift that can occur within minutes if cleanroom air handling degrades. The film passes MIL-STD-3010B class 1 puncture resistance testing and is supplied slit to widths matching tray flange dimensions from 60 mm to 220 mm.
Field trials under EN 17033 confirm that a 25 µm non-water soluble PVA mulch film formulated with 15–20% starch-grafted plasticizer and 2% carbon black loses 90% of its initial tensile strength after 120 days of soil burial at 25°C and 60% water-holding capacity. The film is manufactured on a blown-film line with a die gap of 0.8 mm; the temperature profile from 180°C at the feed zone to 210°C at the die is strictly maintained to avoid acetaldehyde formation that would inhibit soil microorganisms. Application rates in horticulture average 600–800 kg of film per hectare. The material complies with ISO 17556 ultimate aerobic biodegradation criteria, reaching >70% mineralization within 365 days. One operational constraint is the film’s sensitivity to early-season heavy rain; mechanical perforation with 40 mm spacing is therefore applied to prevent water pooling and tear propagation. After harvest, the residual film is ploughed into the topsoil, eliminating collection and landfill cost. Crops trialed include processing tomatoes and strawberry runners where soil warming drives early yield.
For ethylene oxide and gamma-sterilized medical device packages, a 30 µm film of non-water soluble PVA is laminated to 60 g/m² uncoated medical-grade paper using a spot-pattern polyurethane adhesive with coverage below 25% to preserve porosity for gas flooding. The pore-free structure of the PVA layer delivers a microbial barrier rating of log reduction value >5.0 against Staphylococcus aureus as tested under ASTM F1608. Compliance is to EN 868‑5 for sealable transparent lidding and to ISO 11607‑1 for terminally sterilized medical devices. Heat-sealing is conducted on rotary platen equipment with jaw temperatures of 135–150°C. A seal strength window of 1.5–2.5 N/15 mm is maintained to facilitate aseptic peel opening. Prior to lamination, the PVA film is conditioned for 48 hours at 23±2°C and 50±5% RH to stabilize moisture content; failure to equilibrate results in micro-wrinkle formation during unwinding that creates leak paths. The finished pouch or header bag accommodates single-use syringes, catheters, and surgical drapes. Periodic bioburden testing per ISO 11737‑1 is required on retained samples from each production batch to verify consistency.
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In packaging sectors where temporary moisture contact must not compromise film integrity, conventional water-soluble polyvinyl alcohol (PVOH) films exhibit a fatal limitation: dissolution upon contact with liquid water or condensation. The non-water-soluble PVOH film family, commercialised under the grade series NS-PVOH-20, NS-PVOH-25, and NS-PVOH-35, eliminates this failure mode through a controlled network of intermolecular acetal cross-links. This molecular architecture restricts chain solubilisation while preserving sufficient hydrophilicity to permit ultimate biodegradation in soil composting environments evaluated per ISO 14855-1:2012. The film is manufactured by blown-film extrusion on a single-screw line equipped with a grooved feed section, a barrier screw of 30:1 L/D ratio, and automatic gauge control. Production-scale data from a 45 mm extruder operating at 50 rpm with die gap 0.8 mm show that the resulting film maintains a gel content—determined by ASTM D2765-16—between 55 % and 85 %. This gel fraction correlates directly with the inability to dissolve in demineralised water at temperatures up to 40 °C. A 6-month field trial on a multi-head weigher bagging line for 25 kg ammonium nitrate prills, conducted during monsoon-season storage under unroofed sheds, recorded zero wet-bag ruptures for the non-water-soluble variety, whereas standard cold-water-soluble PVOH sacks disintegrated within 72 hours of the first heavy rain.
Water insolubility is not an intrinsic property of the vinyl alcohol backbone but is imparted by post-polymerisation acetalisation with a short-chain dialdehyde cross-linker. The process generates interchain bridges that convert the linear, water-soluble PVOH into a three-dimensional gel network. The gel fraction, quantified by extraction in boiling water for 6 hours in accordance with ASTM D2765-16 Method A, serves as the primary grade-differentiation metric. A gel fraction of 55 % in the NS-PVOH-20 grade yields a swelling ratio of 35–40 % by mass after 24-hour immersion in water at 23 °C, while NS-PVOH-35 at 85 % gel fraction swells less than 15 %. Both grades remain as integral, handleable films that can be heat-sealed without leakage, whereas a standard water-soluble PVOH film with gel fraction near zero dissolves completely within 30 seconds under the same conditions. The degree of cross-linking also modulates the water vapour transmission rate: a higher gel fraction reduces the equilibrium moisture sorption, lowering the permeation coefficient but never approaching the hydrophobic barrier of polyolefins. Consequently, the film is best characterised as a swellable, non-dissolving hydrophilic barrier rather than a moisture-proof layer.
On horizontal form-fill-seal machines running at speeds above 60 cycles per minute, the surface resistivity of non-water-soluble PVOH film can reach 1012 Ω/sq when ambient relative humidity drops below 30 %. This charge accumulation induces static cling that interferes with photocell registration and causes machine stops. Trials on a Bosch SVE 2520 vertical bagger processing NS-PVOH-25 film of 45 µm thickness showed that the misfeed rate rose to 8 % of cycles without antistatic treatment. Application of a fatty acid amide-based antistatic masterbatch at a let-down ratio of 1.2 wt%, co-extruded as a 3 µm surface layer, reduced the incidence to <0.5 % while preserving heat-seal strength. Seal-strength testing per ASTM F88/F88M-21 at a jaw temperature of 150 °C and 0.3 MPa pressure with 1.0 second dwell time gave consistent values of 8.5 N/15 mm. No delamination of the antistatic layer was observed during sealing. The film’s surface chemistry must remain free of amine-based slip additives, as free amines catalyse transacetalisation reactions that progressively reduce gel fraction below 40 %, restoring cold-water solubility over a 3-month warehouse period.
The three commercial grades are differentiated by cross-link density, thickness, and targeted oxygen barrier. The table below summarises key physical properties determined under standard laboratory conditions (23 °C, 50 % RH after conditioning for 48 h). All measurements represent machine-direction values unless specified otherwise.
| Property | Test Method | NS-PVOH-20 | NS-PVOH-25 | NS-PVOH-35 |
|---|---|---|---|---|
| Nominal thickness | ISO 4593:1993 | 35–40 µm | 40–50 µm | 50–75 µm |
| Gel fraction | ASTM D2765-16 | 55 ± 5 % | 70 ± 5 % | 85 ± 3 % |
| Tensile strength at break (MD) | ASTM D882-18 | 48 MPa | 55 MPa | 62 MPa |
| Elongation at break (MD) | ASTM D882-18 | 320 % | 280 % | 210 % |
| WVTR, 38 °C/100 % RH | ASTM F1249-20 | 850 g/(m²·day) | 620 g/(m²·day) | 410 g/(m²·day) |
| OTR, 23 °C/0 % RH | ASTM D3985-17 | 0.8 cm³/(m²·day·atm) | 0.5 cm³/(m²·day·atm) | 0.3 cm³/(m²·day·atm) |
| Heat seal initiation temperature | ASTM F88/F88M-21 | 128 °C | 132 °C | 138 °C |
Oxygen transmission rates measured at 23 °C and 85 % RH are typically 8–15 times higher than the 0 % RH values shown, because moisture plasticises the matrix and increases free volume. The equilibrium moisture content of the film at 85 % RH reaches 12–18 wt%, yet the film does not dissolve; it remains a pliable, non-tacky layer suitable for lamination into multi-material structures.
When the film is used as the interior liner of paper sacks for hygroscopic construction chemicals, dimensional stability under cyclic humidity must be confirmed. Laboratory conditioning between 20 % and 80 % RH in 6-hour cycles over 14 days revealed a reversible hygroexpansion of 0.9–1.3 % in the machine direction, measured by digital image correlation. This expansion reduces Elmendorf tear resistance (ASTM D1922-15) by up to 40 % from the dry-state value, placing the tear force of NS-PVOH-25 at 80-µm thickness at 420 mN after equilibration at 80 % RH, down from 700 mN at 20 % RH. Sack manufacturers compensate by increasing the basis weight of the outer kraft layer rather than altering the film grade. Published data for the long-term mechanical stability of this configuration under combined loading and moisture is limited; ongoing in-field monitoring of cement-bag breakage rates during intermodal transport at 35 °C and 85 % RH is necessary.
The processing window for non-water-soluble PVOH films is narrow and carries a high penalty for deviation. The recommended melt temperature during blown-film extrusion is 195–205 °C, measured at the adaptor with a flush-mounted thermocouple. Pre-drying of the compound is mandatory: residual moisture must be reduced to <0.08 % using a desiccant dryer operating at 80 °C for a minimum of 4 hours, with a dew point of -40 °C or lower. Failure to achieve this moisture level results in bubble instability and a hazy film with entrapped microvoids. At melt temperatures between 210 °C and 215 °C, the gel content begins to increase during the residence time inside the barrel, as residual acetal groups react further. Production logs from a 45 mm single-screw extruder (L/D 30) running NS-PVOH-25 recorded a rise in melt pressure from 210 bar to 310 bar within 20 minutes when the barrel temperature setpoint was accidentally shifted 10 °C high, accompanied by surging and a 15 % reduction in output. Above 215 °C, localized gel particles form and appear as transparent “fisheyes” in the film, and the film colour shifts to a pale amber. To mitigate this sensitivity, processors install melt filtration packs of 60/80/60 mesh and limit screw residence time by operating at moderate speeds (40–60 rpm). The addition of acidic processing aids must be avoided: acidic residues catalyse hydrolysis of the acetal cross-links at elevated temperatures, effectively reversing the insolubility and producing a film that will partially dissolve during subsequent moisture contact.
The value proposition of non-water-soluble PVOH film becomes clear when it is positioned against chemically similar materials used for barrier packaging. The following table benchmarks a representative grade, NS-PVOH-25, against a standard cold-water-soluble PVOH film (fully hydrolysed, 98 mol%) and a commercial ethylene vinyl alcohol copolymer containing 32 mol% ethylene.
| Property | Test Standard | Standard Water-Soluble PVOH | Non-Water-Soluble PVOH (NS-PVOH-25) | EVOH (32 mol% Ethylene) |
|---|---|---|---|---|
| Solubility in water at 23 °C | Visual, 1 h immersion | Complete dissolution in <30 s | Insoluble; swells 15–20 % | Insoluble; no swelling |
| OTR at 0 % RH, 23 °C | ASTM D3985-17 | 0.4 cm³/(m²·day·atm) | 0.5 cm³/(m²·day·atm) | 0.5 cm³/(m²·day·atm) |
| OTR at 85 % RH, 23 °C | ASTM D3985-17 | Film dissolves | 6.5 cm³/(m²·day·atm) | 4.2 cm³/(m²·day·atm) |
| WVTR at 38 °C/90 % RH | ASTM F1249-20 | Not measurable post-dissolution | 620 g/(m²·day) | 25 g/(m²·day) |
| Heat seal initiation | ASTM F88/F88M-21 | 120 °C | 132 °C | 145 °C |
| Biodegradation, aerobic composting (58 °C) | ISO 14855-1:2012 | 92 % in 90 days | 88 % in 180 days | 0 % (non-biodegradable) |
The data highlight that the non-water-soluble PVOH film retains the excellent dry-condition oxygen barrier of standard PVOH while surviving humidity regimes that would dissolve a water-soluble analogue. However, its water vapour barrier is inferior to that of EVOH, meaning the film is not suitable as a stand-alone high-moisture-barrier layer. Its primary advantage lies in providing a combination of moderate oxygen barrier, moisture-triggered fragmentation behaviour, and industrial compostability without requiring a tie-layer adhesive when laminated to paper or board.
Regulatory certification applicable to the NS-PVOH series includes compliance with EC No. 1935/2004 for food contact materials when the film is used as a functional barrier behind a layer of paper or aluminium foil. The specific migration limit for vinyl acetate monomer must not exceed 12 mg/kg food simulant under testing conditions of EN 1186-1:2002, a requirement routinely satisfied by the elevated cross-link density that restricts low-molar-mass fragment migration. Direct monolayer contact with high-acid foodstuffs having pH less than 3.5 at temperatures above 60 °C is contraindicated: acid-catalysed hydrolysis of the acetal bridges reduces gel content below the threshold of integrity, eventually resulting in partial dissolution and loss of package tightness.
