| HS Code | 698886 |
| Chemical Name | Poly(vinyl butyral) Resin |
| Cas Number | 63148-65-2 |
| Chemical Formula | (C8H14O2)n |
| Appearance | White fine powder or granules |
| Density | 1.08 - 1.12 g/cm³ |
| Glass Transition Temperature | 55 - 70 °C |
| Softening Point | 100 - 120 °C |
| Refractive Index | 1.48 - 1.49 |
| Water Absorption | ≤1% (24 h immersion) |
| Tensile Strength | 40 - 60 MPa |
| Elongation At Break | 50 - 100% |
| Solubility | Soluble in alcohols, ketones and esters; insoluble in aliphatic hydrocarbons and water |
| Molecular Weight Range | 20,000 - 200,000 |
| Hydroxyl Content | 18 - 23% |
| Butyral Content | 75 - 82% |
| Uv Resistance | Good |
| Light Transmittance | >90% (in film form) |
As an accredited Polyvinyl Butyral Resin PVB factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Polyvinyl Butyral Resin PVB is packaged in 25 kg moisture-proof laminated kraft paper bags with inner polyethylene lining, palletized and shrink-wrapped. |
| Container Loading (20′ FCL) | 20′ FCL shipment of Polyvinyl Butyral Resin PVB, loaded as palletized bags, ensuring secure, dry, and stable transport. |
| Shipping | Polyvinyl Butyral Resin (PVB) typically ships as non-hazardous powder or pellets in sealed multi-layer bags, FIBCs, or drums. Protect from moisture, heat, and direct sunlight during transit. Keep packaging intact to prevent dust generation. No dangerous goods classification generally applies, but standard industrial hygiene and local transport regulations must be followed. |
| Storage | Store Polyvinyl Butyral (PVB) resin in a cool, dry, well-ventilated area, away from direct sunlight and heat sources. Keep containers tightly sealed to prevent moisture absorption, which degrades quality. Maintain moderate temperatures, avoid open flames, and follow manufacturer’s shelf-life guidelines. Handle with clean, dry equipment to preserve powder properties. |
| Shelf Life | Store in a cool, dry, sealed container. Shelf life is typically two years from manufacture if kept dry and protected from heat. |
In automotive and architectural safety glass production, PVB interlayer sheet is compounded from polyvinyl butyral resin grades with residual hydroxyl content between 18.5 mol% and 20.5 mol%. Interlayer that is to meet HUD wedge-angle tolerances is extruded within a melt temperature band of 185 °C ± 5 °C because excursions above 195 °C accelerate decomposition of the incorporated UV absorber and raise yellowness index measured per ASTM E313 beyond OEM acceptance limits. The compounding formulation uses 100 parts PVB resin, 28 phr to 36 phr triethylene glycol bis(2-ethylhexanoate) plasticizer, 0.2 phr to 0.6 phr UV stabiliser, 0.1 phr to 0.3 phr hindered phenolic antioxidant, and 0.01 phr to 0.05 phr potassium or magnesium acetate as adhesion control. The glass-to-PVB pummel adhesion target is typically 5 to 8 on the ten-point pummel scale used by interlayer suppliers, but this is not an ISO method and must be fixed between interlayer supplier and glazing fabricator. Pre-drying at 60 °C for 4 h lowers moisture to 0.10 wt%; lamination plants in climates above 60% RH must condition film in sealed storage at 22 °C ± 3 °C and 25% RH before lay-up. Twin-screw extrusion on a 36:1 L/D machine with vacuum devolatilisation at -80 kPa discharges through a flat die onto a chill roll; sheet thickness pins are set at 0.38 mm, 0.76 mm, 1.14 mm, or 1.52 mm. Glass lay-up is tack-rolled at 110 °C, then autoclaved at 140 °C under 1.2 MPa for 45 min to 90 min. Residual moisture above 0.15 wt% creates autoclave bubbles, and melt temperatures above 195 °C lower pummel adhesion into a rejected band. Compliance anchoring includes ECE R43 Annex 3, ANSI Z26.1, ISO 12543-2:2021, ISO 12543-3, EN 12600, and EN 15152 for railway glazing. Terminal products include laminated windshields with HUD wedge angles below 0.4 mrad, acoustic interlayers for electric vehicle side glazing, architectural safety glazing, and railway front windows.
PVB resin in two-component acid-catalysed wash primers is encountered on structural steel lines where ambient-cure pretreatment must be overcoated within 30 min to 4 h. The primer is compounded at 4.0 wt% to 7.5 wt% PVB, 3.0 wt% to 5.0 wt% phosphoric acid, 8.0 wt% to 12.0 wt% zinc phosphate, and 75 wt% to 85 wt% isopropanol or denatured ethanol. SSPC-Paint 27 describes this class of vinyl butyral wash primer; where military qualification remains relevant, MIL-P-15328 historical limits on zinc chromate govern replacement testing under local VOC restrictions. The pot life after acid addition is 8 h at 25 °C, after which viscosity rises above 25 s on a Ford #4 cup. Application is by air atomising spray at 0.12 MPa to 0.20 MPa nozzle pressure with wet film thickness 8 µm to 15 µm, producing dry film 4 µm to 8 µm. Dry adhesion is measured by ASTM D3359 cross-cut to minimum class 4B; adhesion after water immersion follows ASTM D870 for 24 h. The wash primer is not a stand-alone coating, and topcoat application beyond 24 h can produce intercoat delamination because the acid surface converts to a water-soluble phosphate that requires reactivation by abrasion. Terminal uses include bridge steel, galvanised air-handling duct, marine container frames, and machined aluminium aerospace parts requiring temporary corrosion protection before structural adhesive bonding.
In snack packaging gravure printing, PVB resin is introduced as the film-forming binder in surface-print ink and overprint lacquer formulations at 6.0 wt% to 12.0 wt% of the liquid ink. The solvent blend of ethanol and ethyl acetate accounts for 65 wt% to 75 wt%, plasticizer 2.0 wt% to 4.0 wt%, and inorganic pigment 25 wt% to 35 wt% for white or metallic grades. Dispersion occurs in a bead mill at tip speed 1,800 rpm to 2,500 rpm to a grind gauge value below 5 µm for process inks and below 3 µm for clear overprint lacquers. The press may run at 80 m/min to 150 m/min with a gravure cylinder cell depth of 60 l/cm to 80 l/cm and drying tunnel air temperature 55 °C to 75 °C. Bond strength after dry lamination to metallised BOPP or PET is measured per ASTM F904 and must remain above 2.0 N/15 mm when PVB replaces nitrocellulose in an identical white ink. For food-contact end use, the finished printed substrate must comply with FDA 21 CFR 175.300 resinous polymeric coating extractive limitations, and when sold in the EU the laminate must not exceed the overall migration limit of 10 mg/dm² under Regulation (EU) No 10/2011. Terminal products include dry snack pouches, chocolate bar wrappers, sugar confectionery packs, and cold-fill beverage bottle labels. The operational boundary is re-solubilisation: PVB inks are attacked by ethyl acetate-based polyurethane lamination adhesives, so a non-PVB overprint lacquer or a solventless lamination process must be specified for retort pouches and high-acid barrier laminates.
Barium titanate slurries for multilayer ceramic capacitors are often prepared with PVB as the sole high-molecular-weight binder because its clean burnout profile leaves residual carbon below 0.02 wt% by 500 °C under a 1 °C/min ramp. The slurry is formulated with 100 parts ceramic powder, 4.0 parts to 8.0 parts PVB, 2.0 parts to 4.0 parts butyl benzyl phthalate, 0.5 parts to 1.0 parts fish oil dispersant, and 60 parts to 90 parts of a 60:40 toluene/ethanol solvent blend. The suspension is processed by two-stage ball milling at 60 rpm for 24 h per stage, deaerated under 5 kPa vacuum, and cast onto silicon-coated PET at 0.4 m/min to 1.2 m/min with a doctor blade gap of 200 µm to 400 µm. Drying at 70 °C produces a green tape with thickness tolerance ± 3 µm and tensile strength measured by ASTM D882 above 6 MPa. The tape is screen-printed with nickel or silver-palladium electrode paste, stacked, and laminated at 70 °C and 20 MPa before a binder burn-out step at 450 °C to 550 °C and sintering at 1,150 °C to 1,300 °C depending on dielectric formulation. Compliance for the finished component follows RoHS 2011/65/EU for lead-free terminations and AEC-Q200 for automotive-grade qualification. Terminal products include X7R and X5R multilayer ceramic capacitors, LTCC substrates for RF modules, and piezoelectric actuators. Operational boundaries include slurry gelation above 60% RH and orange-peel surface defects when free water exceeds 0.10 wt% of solvent mass.
PVB encapsulant film for building-integrated photovoltaics is produced from resin grades with residual hydroxyl content at the higher end of the commercial range, typically 20.0 mol% to 22.0 mol%, to limit moisture ingress along the edge seal. The film formulation uses 100 parts PVB and 28 phr to 36 phr plasticizer, with UV absorber and antioxidant loadings adjusted so that yellowness index shift after 1,000 h of 85 °C/85% RH damp heat exposure remains below 0.5 units when measured by ASTM E313. The laminate stack is glass, PVB, cell string, PVB, glass, and is processed through nip-roller deaeration at 110 °C followed by autoclave at 145 °C and 1.2 MPa to 1.4 MPa for 40 min to 60 min. Compliance is assessed under IEC 61730-1:2023, UL 61730-1, EN 50583 for building-integrated photovoltaic systems, and EN 12600 for retained safety-glass impact resistance. Terminal products include BIPV curtain-wall units, skylight modules, and solar glass spandrel panels. The operational boundary is edge moisture: once the exposed PVB edge reaches 0.5 wt% water content, adhesion at the glass interface declines below the minimum lap shear value required by the module certification programme, so edge sealants and desiccant-filled spacer tapes are specified for facade applications.
When a transparent heat-sealable PVB lacquer is roller-coated onto 250 µm PET or 300 µm PVC for smart card overlays, the dry adhesive film is formed from 10.0 wt% to 15.0 wt% PVB solids, 2.0 wt% to 4.0 wt% acetyl tributyl citrate plasticizer, and 2.0 wt% to 5.0 wt% rosin ester tackifier in an ethanol/toluene solvent blend. The lacquer is applied at 4 g/m² to 6 g/m² dry coat weight, dried at 70 °C, and heat-sealed at 90 °C to 110 °C under 3 bar to 5 bar nip pressure. The sealed assembly is tested to ASTM F88 with minimum 8 N/15 mm for overlay delamination. Food-contact use in dry packaging falls under FDA 21 CFR 175.105 adhesive provisions; toy contact requires EN 71-3 migration compliance. Terminal products include smart card overlay films, holographic foil lamination, and blister lidding for dry pharmaceutical units. The operational boundary is thermal resistance: continuous service above 60 °C reduces seal strength below the specified 8 N/15 mm, and the adhesive is not resistant to boiling-water delamination tests required for dishwasher-safe or retortable packaging.
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Polyvinyl butyral resin (PVB; CAS 63148-65-2) is a thermoplastic polyvinyl acetal produced by the acid-catalyzed condensation of polyvinyl alcohol with n-butyraldehyde. The resin is supplied as free-flowing granules, powder, or preplasticized sheet; raw resin moisture content is normally held below 0.3 wt% by Karl Fischer titration according to ISO 15512. Density at 23 °C is typically 1.08–1.12 g/cm³, measured under ISO 1183-1. Commercial model designations are manufacturer-specific and generally encode molecular weight class and residual polyvinyl alcohol content, but the suffix codes are not harmonized across suppliers. Raw resin specifications commonly fall within polyvinyl alcohol content 9–24 wt%, butyral content 70–88 wt%, and acetate content 0–5 wt%. The nonplasticized resin has a glass transition temperature of 62–78 °C and a thermal degradation onset above 200 °C, where butyraldehyde evolution is detected. Primary uses include laminated safety glass interlayer, ceramic green-tape binder, structural adhesive, wash primer, and solvent-borne ink binder. The material differs from other interlayer resins because glass adhesion is generated by hydrogen bonding without a silane primer, and because the interlayer remains physically bondable and reversible rather than crosslinked.
The specification sheet for a raw PVB resin is organized around three compositional variables: residual polyvinyl alcohol content, which controls hydrogen-bonding capacity; acetate content, which affects solubility and thermal stability; and molecular weight, which governs solution viscosity and melt strength. Downstream grade selection therefore cannot be reduced to a single universal model. Table 1 summarizes neutral grade classes reported in public technical literature for typical conversion applications.
| Grade class | Polyvinyl alcohol content (wt%) | Butyral content (wt%) | Acetate content (wt%) | Viscosity of 10% solution (mPa·s) | Typical downstream use |
|---|---|---|---|---|---|
| Low-hydroxyl, low-viscosity | 9–12 | 82–88 | 0–3 | 5–15 | Flexographic and gravure inks, wash primers |
| Medium-hydroxyl, medium-viscosity | 14–18 | 78–85 | 0–2.5 | 15–40 | Ceramic binders, industrial coatings, structural adhesives |
| High-hydroxyl, high-viscosity | 18–24 | 70–80 | 0–2 | 40–100 | Laminated glass interlayer, high-adhesion laminates |
Values are typical ranges and must be verified against certificate-of-analysis data for the specific lot. The shift from 9 wt% to 24 wt% polyvinyl alcohol increases dry resin tensile strength and glass adhesion but also increases moisture absorption. In solvent systems, high-hydroxyl grades require lower solids loading and release solvent more slowly. Low-hydroxyl grades dissolve faster in alcohol/ester blends and exhibit lower solution viscosity, but their films have reduced glass adhesion and greater sensitivity to polar solvents. Solution viscosity is commonly determined by a Brookfield viscometer under ASTM D2196; melt mass-flow rate of raw PVB is measured under ISO 1133-1 at 190 °C/2.16 kg. Batch-to-batch variation in PVOH content of ±1 wt% is significant in ink dissolution speed and interlayer adhesion control.
Interlayer-grade PVB sheet is melt-compounded with plasticizer, typically triethylene glycol bis(2-ethylhexanoate) or tetraethylene glycol di-n-heptanoate, at 20–40 phr. Compounding on a co-rotating twin-screw extruder with L/D 44:1 and segmented screws keeps melt temperature below 210 °C to limit butyraldehyde regeneration and gel formation. The molten sheet is cast through a slot die onto polished rolls, with standard roll thicknesses of 0.38 mm, 0.76 mm, and 1.52 mm. Thickness tolerance for a 0.76 mm architectural grade is typically ±0.025 mm. Extruded sheet is interleaved with polyethylene release film to prevent blocking. Regrind levels above 10 wt% are associated with increased gel counts and optical defects; edge trim is therefore segregated and blended only into noncritical applications.
Moisture control is the principal processing constraint. The sheet is conditioned at 20–40% RH and 5–25 °C, producing sheet moisture content of 0.4–0.6 wt%. Absolute moisture above 0.8 wt% can generate steam bubbles and visible delamination at the glass interface during autoclave heating. When roll stock has been exposed to ambient conditions above 60% RH, forced-air pre-drying at 45 °C for 4–12 h is required before layup. Moisture content is confirmed by Karl Fischer titration because gravimetric moisture balance is insufficient for interlayer sheet thickness.
Lamination proceeds by layup, de-airing, and autoclave bonding. Nip-roller de-airing is operated at 60–90 °C with line speeds limited to 2–6 m/min; vacuum-bag lines apply 5–10 min of vacuum before edge sealing. Autoclave bonding is performed at 120–150 °C and 1.0–1.5 MPa for 30–90 min. The process is not a chemical cure: hydrogen bonding between PVB hydroxyl groups and silanol groups on glass establishes adhesion. Process deviation above 155 °C produces edge squeeze-out and optical distortion; below 110 °C incomplete de-airing leaves visible bubbles. Optical haze of laminated glass is evaluated under ISO 14782 or ASTM D1003, with automotive windscreen targets commonly below 1.0%. Mechanical fragmentation resistance is validated against ECE R43 or ANSI Z26.1; interlayer tensile properties are measured according to ISO 527-3.
Adhesion level is controlled by residual polyvinyl alcohol content and plasticizer loading, not by an added coupling agent. Excessive adhesion produces localized glass breakage with low energy absorption; insufficient adhesion permits glass spall and reduced post-breakage retention. Glass surface contaminants, particularly amine-based cleaning agents, can interfere with hydrogen bonding and must be removed before lamination. Plasticizer migration toward the edge at elevated storage temperatures may create a white ring defect. This failure mode is observed when finished laminates are stored above 40 °C for extended periods with exposed edges.
For gravure and flexographic ink formulations, low-hydroxyl PVB resins with polyvinyl alcohol content 9–12 wt% are dissolved at 8–15 wt% solids in blends of ethanol, n-propyl acetate, and methyl ethyl ketone. A low-viscosity grade with 10% solution viscosity of 5–15 mPa·s permits high pigment loading while maintaining press-side viscosity below 250 mPa·s at 25 °C. The binder contributes pigment wetting and film toughness, but PVB alone is not appropriate for prolonged water-immersion coatings because the vinyl alcohol segment retains moisture. Crosslinking with blocked isocyanate or phenoplast at 5–12 wt% of binder solids is used for solvent-resistant industrial inks; coating performance is then verified by solvent double rubs and cross-cut adhesion per ISO 2409.
In ceramic tape casting, PVB is dissolved at 6–12 wt% in an ethanol/toluene mixture with a plasticizer-to-binder ratio of 0.25–0.50. The slurry is milled in a high-shear disperser for 6–12 h to achieve a viscosity of 2,500–5,000 mPa·s at 10 s⁻¹, then doctor-blade cast to dry thickness of 100–250 µm. Binder burnout in a belt furnace uses a ramp of 1 °C/min to 350 °C, followed by hold and a secondary ramp to 550 °C. Residual carbon is quantified by loss-on-ignition or thermogravimetric analysis, with total residual organics typically below 0.5 wt%. A medium-viscosity grade is preferred because low-viscosity PVB reduces green-tape tensile strength below acceptable slitting limits.
A direct substitution of PVB for EVA or ionoplast cannot be governed by a single property but by differential moisture response, modulus, and adhesion mechanism. Table 2 compares the three materials under typical safety-glass or encapsulation conditions.
| Property | PVB | EVA | Ionoplast |
|---|---|---|---|
| Adhesion mechanism | Hydrogen bonding via PVOH 9–24 wt%; no silane primer | Silane adhesion promoter plus peroxide crosslinking | Ionic cluster adhesion; silane primer optional |
| Lamination process | Autoclave 120–150 °C, 1.0–1.5 MPa | Vacuum laminator 140–160 °C, 0.08–0.12 MPa, cure required | Autoclave 135–145 °C, 0.8–1.2 MPa |
| Storage humidity | High sensitivity; 20–40% RH | Low sensitivity; vacuum-sealed | Low sensitivity |
| Elastic modulus at 25 °C | 5–20 MPa | 2–10 MPa | 100–300 MPa |
| Moisture-related failure | Edge clouding and plasticizer migration | Hydrolysis and acetic acid formation over time | Low moisture uptake |
| Post-breakage retention | High glass adhesion, moderate modulus | Moderate | High residual load due to high stiffness |
For architectural balustrades and overhead glazing where post-glass-breakage residual strength is the controlling requirement, ionoplast sheets are preferred over PVB because the modulus at 25 °C is 100–300 MPa, compared with 5–20 MPa for plasticized PVB. PVB remains widely used in automotive windscreen production because its processing, fragmentation behavior, and optical performance are established under ECE R43 and ANSI Z26.1. However, PVB is not suitable for continuous service in damp-heat environments above 85 °C/85% RH without specific validation, because hydrolytic degradation and adhesion loss may occur after extended exposure. PVB is also not a drop-in replacement for EVA in photovoltaic encapsulation because higher moisture uptake and plasticizer migration can reduce module insulation resistance over life; EVA remains the standard encapsulation material under IEC 61215 damp-heat testing. Avoid PVB in direct contact with aliphatic hydrocarbon-based sealants that can extract plasticizer. Compared with polyvinyl formal, the longer butyral side chain reduces resin glass transition temperature and increases solubility in lower alcohols; compared with polyvinyl alcohol, the butyral modification eliminates water solubility and large dimensional change. These differences define PVB as a flexible, glass-adhering interlayer and binder rather than a water-soluble film former.
