| HS Code | 891647 |
| Product Name | PVB WW-A-40 |
| Chemical Type | Poly(vinyl butyral) |
| Cas Number | 63148-65-2 |
| Appearance | White to off-white powder |
| Molecular Weight Mw | 40,000 g/mol |
| Viscosity 5 Ethanol Solution 20 C | 40 mPa·s |
| Butyral Content | 70-80% |
| Hydroxyl Content | 18-23% |
| Acetate Content | 0.5-2.0% |
| Water Content | ≤0.5% |
| Density 20 C | 1.08 g/cm³ |
| Refractive Index | 1.488 |
| Glass Transition Temperature | 68°C |
| Softening Point | 90-110°C |
| Solubility | Soluble in ethanol, methanol, isopropanol, and glycol ethers; insoluble in water |
As an accredited PVB WW-A-40 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | PVB WW-A-40 resin is packaged as 25 kg net in multi-wall paper bags with polyethylene inner liner, ensuring moisture protection. |
| Container Loading (20′ FCL) | PVB WW-A-40 is loaded as palletized 25kg bags into a 20′ FCL, securely stowed to prevent shifting. |
| Shipping | PVB WW-A-40 is shipped as polyvinyl butyral resin in solid form, typically powder or granules. It is non-hazardous under normal transport conditions and not regulated as dangerous goods. Pack in sealed moisture-resistant bags, drums, or bulk containers, protected from humidity and heat. Keep away from ignition sources and incompatibles. |
| Storage | Store PVB WW-A-40 in its original, unopened packaging in a cool, dry, well-ventilated area. Keep away from direct sunlight, heat sources, and moisture, as water absorption can degrade quality. Maintain stable temperatures below 30°C (86°F) and moderate humidity. Use within the manufacturer’s recommended shelf life, resealing bags tightly after partial use. |
| Shelf Life | Store in a cool, dry place, protected from moisture and heat. Shelf life: 12 months from date of manufacture. |
In solvent-based rotogravure and flexographic surface printing of corona-treated polypropylene and polyethylene terephthalate films, PVB WW-A-40 is compounded as a co-binder with medium-viscosity nitrocellulose at a PVB:NC dry-weight ratio between 1:3 and 1:5, corresponding to 3–8 wt% of the total liquid ink. The binder is first dissolved in a solvent blend of ethyl acetate, isopropanol, and 1-methoxy-2-propanol at 15–18% solids in a closed high-speed dissolver equipped with a wall scraper, then milled in a horizontal bead mill charged with 0.8–1.2 mm yttria-stabilised zirconia beads to a grind gauge fineness below 15 µm per ISO 1524:2020. The alcohol content must remain above 20 wt% of the solvent phase to keep the resin in solution; replacing isopropanol with n-propyl acetate above 30 wt% of the solvent phase can induce resin precipitation and plate-out on the doctor blade. Press-ready viscosity is adjusted to 16–24 s through a 4 mm DIN EN ISO 2431 cup, and the ink is printed at 120–250 m/min with forced-air drying at 45–60°C. Regulatory compliance for food-contact print is assessed under EU Regulation 10/2011, particularly overall migration limits of 10 mg/dm² for plastic packaging and simulated food contact, and under 21 CFR 175.300 for resinous and polymeric coatings intended for dry, aqueous, and fatty food categories; residual solvent limits are validated by gas chromatographic headspace analysis following ISO 11890-2:2020. Terminal products include surface-printed retort pouches, confectionery twist films, metallised snack wrappers, and lidding films where the ink must withstand pasteurisation at 85–95°C for 30 min without delamination or blocking on the reverse side.
The base component of a two-component wash primer is prepared with PVB WW-A-40 at 4–6 wt% resin solids, 6–9 wt% zinc tetroxychromate, 25–35 wt% isopropanol, 10–15 wt% methyl isobutyl ketone, and the acid diluent contains 2–3.5 wt% orthophosphoric acid 85% in isopropanol. The base and acid diluent are mixed at 4:1 by volume and allowed an induction period of 20–30 min before application; beyond 8 h, viscosity may double and adhesion to aluminium alloy 6061-T6 falls below the ASTM D3359-17 4B acceptance threshold. The mixed primer is spray-applied at 8–12 µm dry film thickness on blast-cleaned steel profiled to Ry 25–40 µm or on chromate-conversion-coated aluminium. Wet film thickness must not exceed 25 µm because the phosphoric acid reaction cannot consume the resin uniformly in a single pass; a second cross-coat without intermediate sanding produces intercoat weakness. The primed surface is topcoated within 4–8 h to prevent atmospheric contamination and to avoid embrittlement of the thin PVB film. Compliance is anchored to MIL-P-15328C for pretreatment wash primer performance and to ISO 12944-5:2019 for atmospheric-corrosivity category selection; hexavalent chromium pigment content makes the formula subject to REACH Annex XIV authorisation and is not recommended for European consumer products, where zinc phosphate or barium metaborate alternatives are used but published data for this specific substitution is limited. Terminal products include pre-treatment coats on bridge girders, galvanized ducting, architectural aluminium extrusions, and aircraft skin repair patches.
| Reference document | Scope | Typical acceptance criterion |
|---|---|---|
| MIL-P-15328C | Pretreatment wash primer | Cross-cut adhesion 4B–5B per ASTM D3359-17 after 7 days at 23 ± 2°C |
| ISO 12944-5:2019 | Protective paint systems | Corrosivity category C3–C5 with approved topcoat |
| REACH Annex XIV | Authorization for hexavalent chromium | Cr(VI) pigment permitted only under existing authorization; articles not for consumer sale |
Tape-casting of barium titanate for multilayer ceramic capacitors incorporates PVB WW-A-40 at 9–13 wt% of the slurry. The ceramic powder, typically 55–65 wt% with a D50 of 0.5–1.0 µm, is first dispersed in an azeotropic MEK/ethanol blend at 25–35 wt% using a phosphate ester dispersant at 0.5–1.5 wt% of the ceramic weight. The resin is added as a 15–20% solution, followed by 2–4 wt% butyl benzyl phthalate plasticizer and vacuum de-airing at 50–100 mbar until viscosity stabilises between 1.5–3.0 Pa·s at 25°C. Doctor-blade gaps of 0.5–1.2 mm and carrier speeds of 0.5–2.0 m/min produce green tape from 20–100 µm; the ASTM D638-14 tensile strength of unsintered tape is typically 2–6 MPa, sufficient for blanking and screen-printing without edge tearing. During co-firing, the binder burnout segment between 250°C and 600°C is limited to 0.2–1.0°C/min under flowing air at 10–20 chamber air changes per hour. A heating rate above 1.0°C/min or local carbon residue above 0.02 wt% produces blisters, laminate delamination, and reduced insulation resistance in the fired dielectric. Compliance is mapped to IEC 60384-14:2023 for fixed capacitors for electronic equipment and to RoHS Directive 2011/65/EU Annex II for lead and cadmium restrictions; the binder must also meet REACH Article 33 communication obligations when residual phthalate plasticizer exceeds 0.1 wt%. Terminal products include MLCC dielectric layers, LTCC substrates, piezoelectric actuator sheets, and sensor membranes.
Heat-seal lacquers for sterilizable aluminium foil lids are compounded with PVB WW-A-40 dissolved in ethanol/ethyl acetate 4:1 at 15–20% solids. The lacquer formulation contains 15–25 wt% PVB by dry solids, 0.5–1.5 wt% carnauba or polyethylene wax, and a maleic-modified rosin ester at 2–5 wt% to shift seal initiation to 170–190°C. Direct gravure coating at 2.5–6.0 g/m² dry coat weight is performed on a multi-roll coater with 40–70 lpi engraved cylinder; drying air at 60–80°C removes solvent to <0.1 mg/m² residual ethyl acetate before rewinding. Heat-seal conditions of 0.8–1.2 s dwell and 3–5 bar jaw pressure produce peel strengths above 4 N/15 mm when sealed to polystyrene or polypropylene cups. Food-contact status is supported by EU Regulation 1935/2004 and FDA 21 CFR 175.300; overall migration must not exceed 10 mg/dm² under OM 2 conditions in EU Regulation 10/2011. End products include sterilizable dairy cup lids, pharmaceutical blister lidding, portion-pack sauce sachets, and cosmetic sample foils.
Prior to two-component polyurethane topcoating, PVB WW-A-40 is incorporated into a solvent-borne wood sanding sealer at 6–9 wt% of the total formulation. The formula also contains a medium-oil alkyd at 18–24 wt%, butylated urea-formaldehyde resin at 6–10 wt%, micronised silica matting agent at 2–4 wt%, and an acid catalyst blocked with p-toluenesulfonic acid at 0.2–0.5 wt%. Application viscosity is adjusted to 18–25 s through a 4 mm DIN cup, sprayed at 90–120 g/m² wet on oak, meranti, and beech. The sealer is force-dried for 20–30 min at 50–60°C and sanded with 280–320 grit stearated paper before topcoat application. The residual hydroxyl content of PVB WW-A-40 contributes to early sanding hardness and reduced grain raise; adhesion is verified by ASTM D3359-17 cross-cut rating of 5B on aged oak, while pendulum hardness after 24 h is assessed by ASTM D4366-16 and should exceed 90 s on glass. For toy applications, the dried film is tested under EN 71-3:2019 for migration of aluminium, barium, cadmium, chromium, lead, mercury, and zinc. Production limitations include pot life of 8–12 h after acid addition and sensitivity to relative humidity above 70%, which can cause blushing in unventilated spray booths. End products include interior joinery, solid-wood furniture, cabinet frames, and children's wooden furniture where migration compliance is required.
After drying the flake to <0.4% moisture, the resin is compounded into plasticised PVB compound for laminated safety glass interlayer with PVB WW-A-40 as the resin constituent at 68–72 wt%, a plasticizer such as triethylene glycol di-(2-ethylhexanoate) at 28–32 wt%, a hindered amine light stabilizer at 0.1–0.3 wt%, and an adhesion control agent at 0.01–0.05 wt% to tune glass adhesion. A desiccant bed or vacuum dryer operating at 60–70°C for 4–6 h is sufficient under RH > 60% ambient conditions. Compounding is carried out on a co-rotating twin-screw extruder with L/D 48:1, residence time below 90 s, and melt temperature controlled between 180°C and 210°C to limit thermal decomposition of residual acetate groups. A slot die feeds a polished chrome chill roll at 30–50°C, producing film of 0.38 mm, 0.76 mm, or 1.52 mm thickness with wavelength-based thickness mapping to ±5% tolerance. Lamination uses pre-press nip air removal followed by autoclave curing at 12–14 bar and 135–140°C for 90–120 min; cooling below 40°C before unloading prevents edge cloud and air bubble re-absorption. Compliance references include ISO 12543-2:2021 for PVB interlayer mechanical and optical properties, EN 12600:2002 for pendulum impact classification, ANSI Z97.1 for safety glazing, and UNECE Regulation No. 43 for automotive glazing. The Pummel adhesion test is conducted at −18°C to verify adhesion index between 3 and 7 depending on application; below 3 indicates excessive adhesion loss after boil-soak, while above 7 indicates high adhesion that can reduce impact energy absorption. Terminal products include automotive windscreens, architectural laminated glazing, hurricane-resistant window systems, and ballistic glass interlayers.
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PVB WW-A-40 is a polyvinyl butyral resin grade supplied as a free-flowing powder or granular solid for solventborne coating, printing ink, ceramic binder, and plasticized interlayer applications. The model designation is used in industrial procurement documents as a medium-viscosity PVB product; the suffix 40 is conventionally read as a supplier-specific viscosity band, and exact batch values should be taken from the certificate of analysis rather than the commercial nomenclature. Polyvinyl butyral resins in this class are statistical terpolymers of vinyl butyral, vinyl alcohol, and vinyl acetate. Class-level data for medium-viscosity PVB grades indicate butyral content of 76–83% by weight, residual polyvinyl alcohol of 14–20% by weight, and vinyl acetate below 2% by weight. The unplasticized glass transition temperature is typically 70–78 °C at a heating rate of 10 °C/min, specific gravity is 1.08–1.12 at 25 °C, and ash residue after combustion is normally below 0.05 wt%. Published product-specific data for PVB WW-A-40 is limited in some public databases; the values above are representative class-level descriptors rather than batch-specific certified limits.
Compared with high-hydroxyl PVB grades, PVB WW-A-40 reduces solvent retention and water sensitivity while retaining enough hydroxyl functionality for adhesion to glass, steel, and aluminum. Compared with low-hydroxyl grades, it provides a greater number of reactive sites for phenolic, melamine, and isocyanate co-reactants. The practical consequence is that PVB WW-A-40 is positioned for industrial coatings where adhesion and film toughness must be balanced against drying speed and storage stability.
Adhesion to glass, aluminum, and ferrous substrates arises from hydroxyl-mediated hydrogen bonding and dipole interactions. In PVB WW-A-40, the residual polyvinyl alcohol content is the primary driver of wetting on high-energy oxide surfaces. At hydroxyl values near the upper end of the typical range, solvent retention increases in polar oxygenated solvents and water sensitivity of the dried film increases. Cross-cut adhesion testing under ISO 2409:2013 on degreased glass frequently gives classifications of 0–1 for formulations containing an epoxysilane or titanate adhesion promoter; without adhesion promoter, performance is more variable. On aluminum, a conversion coating applied at 500–1500 mg/m² chromate or zirconium-titanium passivation is used to stabilize interfacial adhesion under 85 °C/85% relative humidity exposure. The solubility window is narrow in pure ethanol but widens with addition of 10–30 wt% aromatic hydrocarbon or ester co-solvent. Published data for this specific configuration is limited; therefore, adhesion validation should be conducted on the production line with the actual substrate and pretreatment.
Resin selection is typically based on solution viscosity and residual hydroxyl content. Table 1 summarizes representative class ranges for low-, medium-, and high-viscosity PVB resins used in the same application families. The table is not a certificate of analysis for PVB WW-A-40; it is supplied as a decision aid for raw material substitution.
| Grade class | Nominal solution viscosity at 10 wt% in 95:5 ethanol/toluene | Residual PVOH range | Typical application family | Property trade-off |
|---|---|---|---|---|
| Low viscosity | 10–100 mPa·s | 11–14% by weight | Flexographic inks, heat-seal coatings, overprint varnishes | Lower solution viscosity and faster solvent release; reduced toughness and adhesion |
| Medium viscosity | 200–400 mPa·s | 14–18% by weight | Industrial coatings, wash primers, ceramic binders, plasticized interlayers | Balanced adhesion, film toughness, and solubility |
| High viscosity | 500–1500 mPa·s | 18–22% by weight | Laminated glass interlayer film, structural adhesives | Higher melt strength and toughness; slower solvent release and higher water sensitivity |
In high-shear dispersion operations using a vertical cowles disperser with a blade-to-tank diameter ratio of 0.35–0.45, PVB WW-A-40 is typically charged slowly into the solvent phase under low tip speed of 2–3 m/s to avoid lump formation, then dispersed at 8–12 m/s for 30–60 min. Batch temperature should be maintained at 25–35 °C; exceeding 40 °C accelerates solvent loss and causes viscosity drift that complicates downstream coating weight control. Filtration through a 50 µm bag filter after manufacture removes undispersed resin particles. In high-solids formulations above 20 wt%, the solution exhibits pseudoplastic behavior with a yield stress that can exceed 10 Pa at 25 °C; positive-displacement pumps should be selected instead of centrifugal pumps to avoid cavitation. Batch-to-batch viscosity variation in medium-viscosity PVB grades can be controlled by drying resin at 50–60 °C for 4–6 h when storage relative humidity exceeds 60%. Residual moisture above 0.5 wt% damps the hydrogen-bonding network and reduces final coating hardness.
PVB WW-A-40 can be formulated with plasticizer to produce laminated glass interlayer film. Plasticizer loading typically ranges from 15–35 parts per hundred resin depending on glass transition suppression and edge stability. On a co-rotating twin-screw extruder with L/D 44:1, temperature settings from 120 °C at the feed throat to 190–220 °C at the die are used for plasticized PVB compounds. A melt pump upstream of the film die is required to damp pressure fluctuations below ±1.5 bar; film thickness variation is commonly held at ±5% across the web. Moisture in the resin must be below 0.2 wt% before extrusion to prevent bubble defects and hydrolysis-induced molecular weight loss. The extrudate can be quenched on a chilled roll at 10–18 °C; higher roll temperatures produce blocking and uneven release. Edge trim is recycled at 10–20 wt% into the main feed, but higher recycle ratios reduce interlayer clarity because of thermal history effects. Haze measurements according to ISO 14782 on 0.76 mm film typically fall below 1.0% for films processed within these conditions.
Compared with low-viscosity PVB grades, PVB WW-A-40 produces higher melt strength and lower neck-in on flat-die extrusion. In production-scale equipment, melt pressure at the die can exceed 120 bar when plasticizer loading is below 20 phr; increasing plasticizer to 30 phr lowers pressure to 60–80 bar and improves flow, but raises blocking tendency in wound film stored above 25 °C. High-hydroxyl PVB grades generally require higher processing temperatures and can exhibit edge discoloration above 210 °C, whereas medium-viscosity grades with moderate hydroxyl content tolerate brief residence at 220 °C before detectable yellowing. Published data for PVB WW-A-40 in this specific extrusion configuration is limited; the stated ranges reflect industrial practice for medium-viscosity PVB resins and require line-specific optimization.
In flexographic ink applications, PVB WW-A-40 is typically dissolved in a solvent blend of ethanol, ethyl acetate, and n-propanol at 10–15 wt% resin solids. The ink vehicle is milled with a horizontal bead mill charged with 0.6–0.8 mm zirconia beads; mill residence time is set to 20–40 min to achieve a Hegman grind of 6–7. The vehicle’s Newtonian viscosity at 25 °C is commonly 80–150 mPa·s; viscosity is adjusted with additional solvent to 18–25 s in a Zahn cup #2. The dried ink exhibits surface energy in the range 36–40 mN/m, which supports lamination bonding to corona-treated polyethylene and oriented polypropylene at 38–42 mN/m. In side-by-side trials, PVB WW-A-40 shows lower solvent retention than high-hydroxyl PVB grades because the residual hydroxyl content reduces the number of strong ethanol-binding sites; this behavior shortens the required drying tunnel residence time at 60–80 °C by approximately 10–15%. Published data for this specific product in this configuration is limited; trials on production equipment are required to confirm dryer capacity gains.
In two-component wash primers for steel and hot-dip galvanized surfaces, PVB WW-A-40 is milled with zinc tetroxychromate or zinc phosphate at 20–35 wt% pigment volume concentration. The base component is thinned with isopropanol and ethyl alcohol at 10:90 to 20:80 ratios; pH is adjusted with phosphoric acid to 2.5–3.5. Pot life after addition of a phenolic resin hardener is 8–12 h at 25 °C. Salt spray performance per ISO 9227:2017 on cold-rolled steel pretreated with 3–5 g/m² zinc phosphate often reaches 500–1000 h before scribe creep exceeds 2 mm, depending on topcoat chemistry. The resin contributes adhesion through secondary bonding to the phosphate layer; excessive hydroxyl content above 20% can create water sensitivity and adhesion loss, which is why medium-hydroxyl grades are preferred for this application.
Crosslinking of PVB with phenolic resoles or blocked isocyanates produces thermosetting films. In a two-component system using hexamethylene diisocyanate trimer at an NCO:OH molar ratio of 0.8–1.2, pot life is influenced by residual water and solvent polarity. Formulations containing 0.05–0.1 wt% dibutyltin dilaurate catalyst and butyl acetate as the primary solvent show pot lives of 4–8 h at 25 °C. In phenolic-PVB systems, an acid catalyst such as p-toluenesulfonic acid at 0.5–1.0 wt% on resin solids lowers the cure onset temperature from 160 °C to 120–140 °C as determined by differential scanning calorimetry. Film tensile strength per ASTM D638-14 can exceed 30 MPa for crosslinked films, but elongation at break decreases with increasing crosslink density. Avoid addition of amine-functional silanes in isocyanate systems before reaction of the isocyanate because rapid urea formation increases viscosity and reduces pot life.
Storage at 15–30 °C in sealed containers is recommended. The powder will absorb atmospheric moisture when left open at relative humidity above 60%; humid clumps can be broken only by re-drying at 50–60 °C for 4–6 h, and repeated humidification/drying cycles can increase insoluble gel content. Combustible dust handling should follow NFPA 652; generation of airborne PVB dust requires grounding and bonding of transfer equipment, with electrostatic control practices according to IEC 61340-5-1. The resin should not be exposed to strong alkali solutions above pH 12, which hydrolyze residual acetate groups and diminish intercoat adhesion.
Regulatory status depends on the final formulation and national clearance conditions. Table 2 provides a compliance checklist for unmodified PVB WW-A-40 when used in solventborne industrial coatings and adhesives. Confirmation against the latest regulatory text is required before commercial release.
| Standard or regulation | Parameter or method | Representative requirement |
|---|---|---|
| EU RoHS Directive 2011/65/EU Annex II | Lead, mercury, hexavalent chromium, PBB/PBDE | Each 1000 mg/kg maximum; cadmium 100 mg/kg maximum |
| REACH Regulation (EC) No 1907/2006 | Substances of very high concern | No SVHC above 0.1% w/w per article for typical unmodified resin |
| FDA 21 CFR 175.105 | Adhesives component | Subject to functional barrier and migration limitations; finished adhesive must be evaluated |
| ASTM D1396 | Chemical analysis of polyvinyl butyral | Hydroxyl content and acetate content reported on certificate of analysis |
| ISO 9001:2015 | Batch traceability | Lot number linked to incoming resin certificate and production record |
For ceramic binder use, the resin is dissolved in a 70:30 ethanol:toluene mixture at 8–12 wt% solids and blended with alumina or zirconia powders. Suspensions are cast at 25–35 °C; binder burnout is conducted at 500–600 °C in air, leaving ash below 0.1 wt% on ceramic solids. The binder imparts green strength measured by three-point bending; green density is monitored by mercury intrusion porosimetry. Published data for PVB WW-A-40 in specific ceramic tape-cast systems is limited, so binder demand should be established by rheological evaluation using a controlled-stress rheometer at a shear rate of 10–100 s⁻¹.
