| HS Code | 125944 |
| Product Name | PVB for Biomedical Applications |
| Chemical Name | Poly(vinyl butyral) |
| Cas Number | 63148-65-2 |
| Chemical Formula | (C8H14O2)n |
| Molecular Weight | 100,000–250,000 g/mol |
| Glass Transition Temperature | 60–80 °C |
| Density | 1.08–1.15 g/cm3 |
| Water Absorption | 0.1–0.5% (low) |
| Solubility | Soluble in alcohols, esters, and ketones; insoluble in water |
| Biocompatibility | Generally biocompatible for controlled release and tissue engineering applications |
| Tensile Strength | 10–30 MPa depending on formulation |
| Elongation At Break | 50–200% |
| Optical Transparency | High transparency (>90%) in the visible range |
| Adhesion Property | Excellent adhesion to glass, metals, and polymers |
| Sterilization Resistance | Resistant to ethylene oxide; sensitive to heat and high-dose radiation |
As an accredited PVB for Biomedical Applications factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | PVB for Biomedical Applications is supplied in 25 g, 100 g, and 500 g sealed glass bottles under inert gas. |
| Container Loading (20′ FCL) | 20′ FCL: PVB biomedical grade packed in sealed drums, palletized, secured with dunnage, ventilated container, avoiding moisture and contamination. |
| Shipping | PVB for biomedical applications is shipped in sealed, moisture-resistant containers to preserve purity and stability. Transport occurs at controlled ambient temperature, protected from direct sunlight and physical damage. Each shipment includes documentation, safety data sheets, and traceability labels, ensuring regulatory compliance and safe handling throughout delivery. |
| Storage | Store PVB (polyvinyl butyral) in a cool, dry, well-ventilated area at room temperature, ideally 15–25°C. Keep the container tightly sealed to protect against moisture and dust. Avoid exposure to direct sunlight, heat sources, and incompatible chemicals. Handle in a clean environment to maintain biomedical-grade purity. |
| Shelf Life | Shelf life: typically 2 years when stored sealed, dry, at room temperature, protected from light and moisture. |
In transdermal therapeutic systems (TTS) using drug-in-adhesive matrix construction, PVB is incorporated as a release-rate modifier and crystallization inhibitor rather than as the primary pressure-sensitive adhesive. The polymer is pre-dissolved at 12–18 wt% solids in a 70:30 ethanol/ethyl acetate solvent system under high-shear mixing at 1,500–2,500 rpm, then filtered through a 5 µm stainless steel mesh before gravimetric metering into the adhesive mix. Production-scale slot-die coating on siliconized release liner uses multi-zone drying tunnels with zoned air temperatures from 45 °C to 80 °C and air velocities of 2–5 m/s; residual solvent content after drying is verified by headspace gas chromatography against USP 467 and ICH Q3C Option 2. In the dry matrix, PVB loading is evaluated between 5 wt% and 25 wt% relative to total dry adhesive mass; above 30 wt%, published data for this specific configuration is limited, and cold flow under 40 °C storage becomes difficult to control. Polymeric plasticizer content is held at 15–25 phr because lower plasticizer levels produce excessive peel-adhesion loss and higher levels increase plasticizer migration into the release liner. Compliance for skin-contact layers requires USP 661.1, ISO 10993-5:2009 and ISO 10993-10:2010. Peel adhesion is measured according to ASTM D3330/D3330M-04, probe tack according to ASTM D2979-16, and cast film tensile properties according to ASTM D882-18. The downstream process includes lamination to occlusive backing, die-cutting, and foil pouch sealing. Finished product types include analgesic, hormone replacement, and nicotine transdermal patches in which PVB contributes to drug crystal inhibition and modified release kinetics.
| Standard designation | Test parameter | Applied to |
|---|---|---|
| USP 661.1 | Plastic packaging component extractables | PVB skin-contact layer after lamination |
| USP 467 | Residual solvents | Dried matrix before pouch sealing |
| ICH Q3C Option 2 | Class 3 solvent limits | Ethanol, ethyl acetate |
| ISO 10993-5:2009 | Cytotoxicity | L929 cell culture extract |
| ISO 10993-10:2010 | Irritation and sensitization | Skin-contact adhesive surface |
| ASTM D3330/D3330M-04 | 180° peel adhesion | Pressure-sensitive laminate |
| ASTM D2979-16 | Probe tack | Skin-contact adhesive surface |
The mucoadhesive performance of cast PVB buccal films depends on the fraction of free hydroxyl groups available for hydrogen bonding with sialic acid residues in the oral mucosa, not solely on total polymer weight. Commercial PVB grades selected for oromucosal films have residual hydroxyl content between 18 mol% and 22 mol%; below 18 mol% wet adhesion is insufficient, and above 22 mol% water uptake causes swelling and dimensional instability in sustained-release matrices. Formulation is based on dry film mass with PVB at 20–45 wt%, plasticizer such as glycerin or triethyl citrate at 10–25 wt% relative to polymer mass, active pharmaceutical ingredient at 1–10 wt%, and the balance composed of fillers, buffers, or taste-masking agents. Manufacturing is performed on pilot-scale doctor-blade casters with wet film thickness of 200–600 µm on polyester release liner, followed by multi-zone drying at 40–60 °C; residual water is controlled below 3 wt% to prevent blocking during die-cut stacking. Compliance testing includes USP 62, USP 1111, ISO 10993-5:2009, ISO 10993-10:2010, and the European Pharmacopoeia general monograph on Oromucosal Preparations. The dried film is die-cut into individual strips of 10×20 mm with thickness from 50–150 µm. Finished dosage forms include buccal and sublingual films for local and systemic drug delivery.
In spray-on liquid bandage manufacturing, PVB is dissolved at 4–10 wt% in a solvent system of ethanol, ethyl acetate, and n-butyl acetate, with plasticizer content maintained at 20–35 phr using acetyl tributyl citrate or triethyl citrate to prevent film cracking during skin flexion. The solution is filtered through 0.45 µm membrane filters and filled into pump spray containers at 0.4 mL per actuation. On skin, the film must set within 60 s at 25 °C and 40–50% RH; above 70% RH solvent evaporation slows and the film can develop white haze from moisture entrapment. Direct wound-contact compliance requires ISO 10993-5:2009 and ISO 10993-10:2010, and nonsterile topical product limits are verified according to USP 61 and USP 62. Production vessels are explosion-proof stainless steel jackets with nitrogen blanketing; batch-to-batch solution viscosity is held within a narrow range to prevent dip-tube clogging and inconsistent spray patterns. The finished product types include transparent liquid bandages, post-surgical incision sealants, and lightweight barrier films over minor abrasions. PVB is not recommended for heavily exuding wounds because the film’s moisture vapor transmission rate measured by ASTM E96/E96M-16 is lower than hydrocolloid dressings, which can lead to maceration under occlusion.
For pharmaceutical tablet coating, PVB is applied as a 5–12 wt% solution in ethanol or ethanol/water using a side-vented perforated pan coater at a spray rate of 2–6 g/min per kg tablet bed with inlet air at 50–70 °C and outlet air at 35–45 °C to achieve 2–4% tablet weight gain; residual solvent compliance follows ICH Q3C and USP 467, dissolution of the finished coated tablets is verified according to USP 711, and the terminal finished products are immediate-release coated tablets and polymer-coated granules.
Electrospinning of PVB with polycaprolactone (PCL) on pilot-scale equipment produces nanofibrous mats for tissue-engineering scaffolds. The stock solution is prepared by dissolving PCL at 10–14 wt% and PVB at 6–10 wt% in an 80:20 chloroform/N,N-dimethylformamide mixture, fed at 0.5–1.5 mL/h through a 21G blunt needle with applied voltage of 18–22 kV and tip-to-collector distance of 15–20 cm. A rotating drum collector at 500–1,500 rpm controls fiber alignment; chamber conditions are maintained at 22–25 °C and 30–40% RH. Biological evaluation follows ISO 10993-1:2018, ISO 10993-5:2009, and ISO 10993-12:2021, while scaffold characterization is performed according to ASTM F2900-11 and tensile properties according to ASTM D882-18. Fiber diameters and pore-size distributions are measured by scanning electron microscopy. Vacuum drying at 40 °C for 24 h is required before residual solvent analysis against USP 467; any batch exceeding solvent limits is rejected because the scaffold is intended for direct tissue contact. Finished product types include wound-contact nanofibrous layers, cell culture substrates, and dermal regeneration scaffolds. Pure PVB scaffolds exhibit limited hydrolytic degradation at physiological pH; published data for this specific configuration is limited regarding long-term in vivo degradation rates, so implantable devices typically require PCL blending or secondary crosslinking to match tissue turnover.
For screen-printed amperometric biosensors, PVB serves as a water-insoluble enzyme immobilization binder that holds glucose oxidase or lactate oxidase at the working electrode surface without severe swelling. The binder solution is prepared at 0.5–3 wt% PVB in ethanol; enzyme is dispersed at 10–20 U/cm² of electrode area, and crosslinking is performed by exposing the dried membrane to glutaraldehyde vapor at 0.5–2% for 5–15 min. Manufacturing is carried out on semi-automatic screen-printing lines with carbon working electrodes on polyethylene terephthalate substrates; the PVB-enzyme layer is applied by drop-casting or fine-tip dispensing, dried at 30 °C, and conditioned at 35–40% RH for 12 h. Quality management follows ISO 13485:2016; analytical performance of glucose sensors is evaluated according to ISO 15197:2013, and stability protocols align with ISO 23640:2011. The operational boundary is defined by pH: the binder should not be exposed to buffers above pH 8.5 during continuous operation because alkaline hydrolysis of residual acetate groups increases water uptake and enzyme leaching. Finished product types include disposable glucose and lactate test strips and enzymatic electrodes for point-of-care diagnostic analyzers.
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PVB-BM-20 is a purified polyvinyl butyral homopolymer supplied for biomedical device conversion. The resin is a terpolymer of vinyl butyral, vinyl alcohol, and vinyl acetate, produced by acid-catalysed condensation of polyvinyl alcohol with butyraldehyde, followed by water washing, neutralisation, and vacuum stripping. Residual hydroxyl content is controlled to 18–22 wt% expressed as polyvinyl alcohol equivalent, with residual acetate held below 3 wt%. The weight-average molar mass range is 150,000–250,000 g/mol by size-exclusion chromatography using polystyrene calibration. Unlike architectural interlayer resin, PVB-BM-20 is not compounded with phthalate or mixed adipate plasticiser packages. The only permitted flexibilisers are characterised citrate esters or polyethylene glycol grades meeting ISO 10993-5 and ISO 10993-10 extract test requirements. The dry resin is supplied as a free-flowing powder or pelletised compound with a tapped bulk density of 0.45–0.65 g/cm³ measured per ASTM D1895-17.
| Property | Method or standard | Typical specification |
|---|---|---|
| Residual hydroxyl content | Acetylation titration | 18–22 wt% as polyvinyl alcohol equivalent |
| Residual acetate | Saponification titration | ≤3 wt% |
| Weight-average molar mass | Size-exclusion chromatography | 150,000–250,000 g/mol |
| Glass-transition temperature | ISO 11357-2:2020 | 68–75°C unplasticised |
| Ash content | ISO 3451-1:2019 | ≤0.1 wt% |
| Tapped bulk density | ASTM D1895-17 | 0.45–0.65 g/cm³ |
| Water absorption, 24 h | ISO 62:2024 | 0.8–1.5 wt% |
| Tensile strength, solution-cast film | ISO 527-2 | 25–35 MPa |
| Elongation at break, solution-cast film | ISO 527-2 | 150–250% |
| Biological reactivity | USP Class VI | Pass criteria for systemic toxicity, intracutaneous reactivity, and implantation |
| Cytotoxicity | ISO 10993-5 | Pass criteria of standard |
| Bacterial endotoxin | Limulus amoebocyte lysate assay | <0.25 EU/mL for sterile-grade lots |
Three process controls separate biomedical PVB from architecture-grade interlayer resin: residual ionic catalyst concentration, particulate burden, and plasticiser chemistry. Architectural PVB typically contains 3–5 wt% alkaline earth or alkali metal salts for glass adhesion; in PVB-BM-20 total ash is reduced to ≤0.1 wt%. The resin is filtered through 10 µm polypropylene depth media during solution finishing, and the resulting particulate burden is below 200 particles/cm³ at ≥0.5 µm when sampled in an ISO 14644-1 cleanroom environment at ISO Class 7. Residual aldehydes are held below the release threshold for amine-sensitive biomedical applications, because free butyraldehyde can form Schiff-base adducts with amine-bearing biomolecules. Plasticiser, if required for soft wound-contact films, is limited to 15–30 phr acetyl tributyl citrate or PEG 400; these are the only flexibiliser platforms for which migration and cytotoxicity data have been generated under ISO 10993-12 extraction protocols. Heavy metal burden is controlled to the limits of ICH Q3D, and the grade is supplied with lot-specific extractables data measured in polar and non-polar solvents.
Solution casting of PVB-BM-20 is performed on a slot-die coater having a 1.2 m web width, a 3-zone drying tunnel, and a line speed of 3–8 m/min. The solution is prepared at 18–25 wt% solids in anhydrous ethanol or an 85:15 ethanol:methyl ethyl ketone mixture, with a viscosity of 3,000–12,000 mPa·s at 25°C measured per ISO 3219-2:2021. Drying zone temperatures are set at 60°C, 80°C, and 100°C to prevent solvent boiling defects while reducing residual solvent below 500 ppm by headspace gas chromatography. Film thickness from 50 µm to 300 µm is controlled by slot-die gap and pump speed, with cross-web thickness variation held to ±5 µm. This route is suitable for roll-to-roll conversion of wound-contact films and transdermal backing layers. It is not indicated for load-bearing implantable components, because PVB-BM-20 does not undergo hydrolytic backbone degradation and remains dimensionally stable in vivo.
A second conversion route is heat-assisted lamination of borosilicate microfluidic chips. The film, at 25–75 µm thickness, is interposed between glass wafers and pressed at 120–140°C and 0.5–1.0 MPa for 10–20 min. Under these conditions PVB softens without flowing into the channel lumen. The advantage over polyvinyl alcohol bonding is that PVB remains water-insoluble after lamination, so channels do not delaminate during wet storage. The limitation is the aldehyde background; chips intended for amine-derivatised biomolecules require surface passivation before use.
PVB-BM-20 is an amorphous thermoplastic with no crystalline melting endotherm. The glass-transition temperature measured by differential scanning calorimetry at 20 K/min per ISO 11357-2:2020 is 68–75°C for the unplasticised powder, falling to 35–50°C when plasticised with 25 phr acetyl tributyl citrate. In melt extrusion, a 25:1 L/D twin-screw extruder with segmented screws and vacuum venting is operated with a barrel profile from 150°C at the feed throat to 190°C at the die. The melt temperature must not exceed 210°C, because residual hydroxyl groups promote chain scission and yellowing above this boundary. Melt is passed through a 20 µm screen pack before a slit die, and the extrudate is quenched on a chilled roll at 15°C. Melt viscosity at 190°C and 100 s⁻¹ ranges from 800 Pa·s to 2,500 Pa·s depending on plasticiser content, as measured by capillary rheometry per ISO 11443:2021.
For solution spinning or electrospinning, the same resin is dissolved at 8–12 wt% in an 80:20 ethanol:dimethylformamide mixture. The jet is stable at a positive pressure of 0.3–0.8 bar and a tip-to-collector distance of 15–18 cm under 18–25 kV applied potential. Fibre diameters from 250 nm to 700 nm are collected on a grounded drum rotating at 200–500 rpm. The nonwoven is used only as a cell-support matrix or diagnostic membrane, not as a load-bearing scaffold; its tensile strength of 1–3 MPa measured per ASTM D638-14 is below the structural threshold for vascular grafts or osteochondral repair.
When PVB-BM-20 is evaluated against PLGA, polycaprolactone, polyvinyl alcohol, and medical silicone, the selection logic is dominated by degradation profile, water interaction, and thermal processing window.
| Material | Degradation behaviour | Water interaction | Key thermal values | Processing implication |
|---|---|---|---|---|
| PVB-BM-20 | Non-hydrolytic vinyl backbone; drug release is diffusion- or swelling-controlled | Water-insoluble; absorbs 0.8–1.5 wt% | Tg 68–75°C; no Tm | Solution-cast or melt-extruded below 210°C; steam autoclave unsuitable |
| PLGA 50:50 | Bulk hydrolysis; mass loss typically within 4–8 weeks | Absorbs water and swells during degradation | Tg 45–55°C | Electrospinning or solvent casting; hydrolytic degradation restricts shelf stability |
| Polycaprolactone | Hydrolytic degradation exceeding 12 months | Water-insoluble; low equilibrium uptake | Tm 55–60°C; Tg approximately −60°C | Melt extrusion at 70–100°C; slow degradation limits drug release |
| Polyvinyl alcohol | Water-soluble unless crosslinked | Dissolves in aqueous media | Tg approximately 85°C; Tm 180–230°C depending on hydrolysis | Solution casting from water; chemical crosslinking required for implant stability |
| Medical silicone | Non-degradable, crosslinked elastomer | Extremely low water uptake | Service temperature up to 200°C | Moulding or two-part addition cure; no solvent reflow or reprocessing |
A further application route is the coating of screen-printed electrochemical biosensor electrodes. PVB has been used as an enzyme-entrapment membrane for glucose oxidase on carbon electrodes; the film is deposited from a 5 wt% solution in ethanol, yielding a dry thickness of 2–5 µm. The coating introduces a diffusion limitation for small analytes, and electrochemical calibration against the specific electrode geometry is required. Published data for clinical biosensor stability of PVB-coated electrodes remain limited; the available laboratory reports indicate that plasticiser content is the dominant factor controlling analyte flux through the dried membrane.
When a dispersed active pharmaceutical ingredient is incorporated into the PVB matrix, the release mechanism is controlled by drug diffusivity, plasticiser phase partitioning, and particle-size-driven wetting. Unmilled PVB-BM-20 with a D90 of 180–250 µm produces monolithic devices that remain intact and follow Fickian release. When the resin is cryogenically milled under liquid nitrogen to a D90 of 25–50 µm, the same formulation can disintegrate into microparticles, and the release profile may become non-Fickian with a faster initial phase. Milling below 50 µm increases surface area per unit mass by approximately 8–10-fold relative to a 200 µm D90 powder, which accelerates matrix wetting and may introduce disintegration-assisted transport. Published data for sustained-release profiles of PVB in specific drug-loaded biomedical devices are limited; therefore, no universal release rate is assigned, and dissolution testing should follow USP Apparatus 2 or Apparatus 5 depending on film geometry.
Post-processing of PVB-BM-20 requires moisture control at every stage. The resin absorbs 0.8–1.5 wt% water at 50% RH per ISO 62:2024; if powder is held at relative humidity above 60% before melt extrusion, pre-drying in a desiccant dryer with a dew point of −40°C at 60°C for 4 h is required to avoid steam bubbles and die-lip deposits. The product is incompatible with primary amine-containing additives because residual aldehyde groups generate Schiff-base chromophores and increase extractable matter. Strong acidic buffers below pH 3 and strong bases above pH 10 accelerate acetal hydrolysis and are avoided in any contacting medium. Sterilisation by steam autoclave at 121°C is unsuitable for dimensionally constrained PVB parts because the material softens above its glass-transition temperature. Gamma irradiation in the range 25–40 kGy per ISO 11137-2:2013 or ethylene oxide exposure per ISO 11135:2014 is the validated route, provided residual ethylene oxide is desorbed to below 0.5 ppm for blood-contact devices.
