| HS Code | 796355 |
| Product Name | Mowital B 45 M |
| Chemical Type | Polyvinyl Butyral (PVB) |
| Appearance | White powder |
| Viscosity 5 Solution In Ethanol 20 C | 45 mPa·s |
| Hydroxyl Content | ~22% by weight |
| Butyral Content | ~75% by weight |
| Acetyl Content | ~2% by weight |
| Density | 1.1 g/cm³ |
| Glass Transition Temperature | ~70°C |
| Tensile Strength | ~50 MPa |
| Elongation At Break | ~80% |
| Solubility | Soluble in alcohols, ketones, esters; insoluble in water and aliphatic hydrocarbons |
As an accredited Mowital B 45 M factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Mowital B 45 M is supplied in 25 kg multi-layer paper bags with an inner polyethylene liner, ensuring product protection. |
| Container Loading (20′ FCL) | 20′ FCL container loading of Mowital B 45 M: 25 kg bags on pallets, shrink-wrapped, secured for safe transport. |
| Shipping | Mowital B 45 M is a polyvinyl butyral resin supplied as a free-flowing powder. Ship in sealed, moisture-proof bags or drums, dry and ventilated containers. Avoid exposure to humidity, heat, and direct sunlight. Non-hazardous under normal transport conditions; protect from mechanical damage and keep away from ignition sources. |
| Storage | Store Mowital B 45 M in a cool, dry, well-ventilated area away from heat, ignition sources, and direct sunlight. Keep the original container tightly closed to prevent moisture absorption and contamination. Avoid dust accumulation. Under proper storage conditions, shelf life is typically two years. |
| Shelf Life | Shelf life of Mowital B 45 M is typically 2 years when stored unopened in original containers under cool, dry conditions. |
Solvent-based flexographic and rotogravure lamination inks for reverse-printed snack packaging are formulated with Mowital B 45 M as the primary binder because its alcohol-soluble structure provides adhesive interaction with corona-treated low-density polyethylene, cast polypropylene, and polyester films. The resin is dissolved at 10–13 wt% solids in an 85/15 w/w blend of denatured ethanol and n-propyl acetate; the resulting solution viscosity measured per DIN 53015 at 23 °C is in the range 35–55 mPa·s, which permits gravure cup viscosity to be adjusted without excessive solvent addition. Pigment-to-binder ratios are maintained between 1.5:1 and 2.2:1 for organic pigments and between 2.5:1 and 3.0:1 for titanium dioxide, while wetting agent demand is kept below 1.5 wt% of total ink to avoid interlayer surface tension depression in lamination. Grinding is carried out on a high-speed disperser with a Cowles blade tip speed of 15–20 m/s until the Hegman grind gauge reading is below 12 µm; for extended-shade flexo inks, the premix is transferred to a horizontal bead mill charged with 0.8–1.2 mm yttria-stabilized zirconia beads and milled at 1,800–2,400 rpm with outlet temperature limited to 45 °C. During eight-colour flexo printing the ink film is dried at 55–70 °C in a forced-air tunnel with residence time of 1.5–2.5 s before the next deck. The terminal structure is an adhesive laminate for snack packaging; residual solvent after lamination is controlled below 5 mg/m² by gas chromatographic headspace analysis when the converter targets low-odor food-packaging grades. Adhesion is dependent on film surface energy measured by dyne pens per ASTM D2578; corona treatment is set at 40–44 mN/m on LDPE and 50–54 mN/m on BOPP, and adhesion fails when the surface energy falls below 36 mN/m. Batch-to-batch variation in residual polyvinyl alcohol content of ±1 wt% shifts final ink flow time by 8–12% and moves cross-cut adhesion from class 0 to class 1 on low-surface-energy films. Mowital B 45 M is not suitable for untreated polyester or polyethylene surfaces containing more than 2% slip additive because print adhesion becomes too weak and residual tack increases.
On hot-dip galvanized steel and aluminium extrusions, Mowital B 45 M is used as the resin component of a two-part wash primer in which phosphoric acid activates the metal surface and the PVB film provides a temporary corrosion-inhibiting barrier. Part A contains 10–14 wt% Mowital B 45 M dissolved in an 85/15 w/w ethanol/2-butanol mixture, 30–40 wt% zinc tetroxychromate or zinc phosphate, 5–10 wt% talc, and 0.5–1.0 wt% bentonite anti-settling agent. Part B is 85% phosphoric acid diluted 1:4 by volume with isopropanol; the two components are mixed at a volume ratio of 4:1 immediately before application. The pot life at 25 °C is 8 h; at 35 °C pot life falls below 4 h because the acid cleaves the PVB acetal ring, lowering solution viscosity and destroying cohesive film strength, which is a critical boundary condition for summer production lines. Application is performed by HVLP spray at 1.8–2.2 bar and 15–20 cm distance; the dry film thickness is 5–12 µm. Adhesion on galvanized steel after methyl ethyl ketone solvent wipe and nonwoven abrasive scuffing is evaluated by ISO 2409 cross-cut test, with class 0 to 1 required before topcoating. Pull-off adhesion measured per ISO 4624 on zinc-phosphate pretreated substrate is specified at ≥2.0 MPa. Corrosion creep from a scribe after 500 h neutral salt spray under ISO 9227 is less than 3 mm when the wash primer is overcoated with a two-pack alkyd or epoxy topcoat and tested per ASTM D1654. Chromium (VI)-bearing zinc tetroxychromate variants are subject to REACH Annex XIV authorisation, so production lines increasingly use zinc phosphate variants that avoid chromate authorisation but show slower film formation and lower wet adhesion on bright galvanizing. The terminal product is prefabricated galvanized ventilation duct, agricultural equipment brackets, and zinc-coated trailer frames that require a thin conversion primer before final coating.
| Performance criterion | Test standard | Control limit |
|---|---|---|
| Cross-cut adhesion on hot-dip galvanized steel after solvent wipe | ISO 2409 | Class 0–1 |
| Pull-off adhesion on zinc phosphate pretreated substrate | ISO 4624 | ≥2.0 MPa |
| Scribe corrosion creep after 500 h neutral salt spray | ISO 9227 | ≤3 mm |
| Surface cleanliness before primer application | ISO 8501 | Sa 2.5 / St 2 |
| Spray viscosity | DIN 53211 | 18–25 s |
Non-aqueous tape casting of barium titanate for multilayer ceramic capacitor dielectric sheets uses Mowital B 45 M as a sacrificial binder because its ash content after burnout is below 0.1 wt% and the resin dissolves in a 60/40 w/w ethanol/toluene azeotrope. A typical slip contains 100 parts by weight BaTiO₃ powder, 7–12 parts Mowital B 45 M, 1.0–2.5 parts fish oil or phosphate ester dispersant, 1.5–3.0 parts dioctyl phthalate or benzyl butyl phthalate plasticizer, and 80–120 parts mixed solvent. Milling proceeds in two stages: ceramic powder is first milled with solvent and dispersant for 12 h using 3 mm yttria-stabilized zirconia balls at 45–55% critical speed in a polyamide-lined jar, then the PVB binder and plasticizer are added and the slip is milled for an additional 12–18 h at 20–25 °C. The deaired slurry viscosity is adjusted to 1,500–5,000 mPa·s at 10 s⁻¹; this allows a double-ceramic-gap doctor blade to cast green tape at 0.35–1.5 m/min with wet thickness 100–350 µm. Drying is conducted in a laminar-flow oven at 25–35 °C for 15–30 min to avoid binder skin-over that traps solvent and causes pinholes; residual solvent at cutting is specified below 1.5 wt%. The green tape is cut, screen-printed with nickel internal electrodes, laminated at 60–70 °C under 10–20 MPa, and binder burnout is performed in air with a ramp of 0.5–2.0 °C/min to 600 °C and a 2 h hold. Exothermic decomposition of the PVB below 300 °C limits thick laminate sections to the lower ramp range because thermal runaway opens internal delamination. Firing at 1,150–1,250 °C produces the sintered MLCC dielectric; restriction of hazardous substances in the final capacitor is verified by IEC 62321-5 for lead and chromium, while residual ash from the binder must not shift dielectric K and dissipation factor. Published data for Mowital B 45 M in a specific capacitor maker’s proprietary tape formulation is limited, but the general binder content window is set by green tensile strength above 1.0 MPa and elongation above 3%.
Lidding foils for cosmetic and pharmaceutical sachet packs are coated with Mowital B 45 M lacquers at 8–12 wt% solids in 70/30 w/w methyl ethyl ketone/ethanol. Plasticizer content is 20–35 phr; dioctyl phthalate or triethylene glycol bis(2-ethylhexanoate) lowers the seal initiation temperature to 90–110 °C, while the unplasticized resin has a glass transition of 62–68 °C as measured by DSC per ISO 11357-2. The lacquer is applied by direct gravure at 2–4 g/m² dry coating weight and dried at 80–120 °C with 3–5 s residence, with online film weight controlled by near-infrared backscatter. Sealing is performed on a tray sealer with PTFE-coated platens at 160–190 °C, 0.3–0.5 MPa and dwell of 1–2 s. Seal strength is measured on 25 mm strips per ASTM F88/F88M-21 and reaches 4–8 N/15 mm on unprimed 20 µm aluminium foil when the foil surface is free of rolling oil; above 200 °C the coating yellows and peel performance drops because the PVB undergoes thermal degradation and crosslinking. The terminal product is a lap-seal lid for cosmetic and pharmaceutical sachet packs, but direct food-contact status must be verified for the specific formulation under national legislation because plasticizer and residual ketone migration can exceed defined overall migration limits if coating weight and drying are not controlled.
Screen-printable glass enamel pastes for architectural and automotive glazing use Mowital B 45 M as the organic vehicle binder because it decomposes cleanly before the glass frit fuses. A typical screen-printing paste contains 60–80 wt% low-melting glass frit, 10–20 wt% ceramic pigment, 8–15 wt% PVB binder solution, and 3–8 wt% high-boiling solvent such as butyl carbitol or terpineol. The binder solution itself is made at 25–30 wt% Mowital B 45 M dissolved in 50/50 w/w butyl carbitol/ethanol; the final paste is passed once through a three-roll mill with roll gaps of 10–20 µm and paste viscosity of 20–40 Pa·s at 0.1 s⁻¹. Screen printing uses a 200–325 mesh stainless steel screen with 10–15 µm emulsion thickness, a 70 Shore A squeegee, and snap-off of 2–4 mm; the wet print is dried at 120–160 °C for 8–12 min to remove solvent without blistering. Firing in a continuous tempering furnace follows a 580–650 °C peak for automotive side-lite black enamel; the binder decomposition region is 200–400 °C and requires oxygen-containing atmosphere with extraction to prevent carbon residue. The performance criteria after firing are scratch adhesion and acid resistance per ASTM C724-91, glass fracture strength reduction below 20% compared with unprinted glass, and residual carbon below 0.05% to avoid pinholes from binder outgassing. This application does not require binder permanence, so moisture resistance and solution viscosity stability are less critical than clean depolymerization; however, use of lead-bearing glass frit is prohibited in electrical and electronic automotive parts under RoHS 2011/65/EU.
For mahogany and oak furniture undercoats, Mowital B 45 M is dissolved at 12–15 wt% in denatured ethanol with 3–5 wt% butyl acetate to slow flash-off. A 0.8–1.2 mm fluid nozzle HVLP spray gun at 1.2–1.8 bar applies a wet film of 80–120 µm; the first coat is sanded after 30–40 min with P240–P320 paper. Each subsequent coat raises the grain; the schedule consists of two build coats and one final sealer coat before nitrocellulose lacquer topcoat. Solids content and viscosity are monitored by ISO 3251 and DIN 53211 flow cups; adhesion to residual sanding dust is poor if the surface is not wiped with an ethanol-dampened cloth. The PVB sealer forms a flexible film with good intercoat adhesion, but it is not suitable for exterior wood because permanent water immersion causes blushing and hardness loss above 85% relative humidity. The terminal product is interior furniture cabinetry with a closed-pore substrate for nitrocellulose lacquer; the sanding sealer layer must not exceed 100 µm total dry thickness to avoid plasticizer-free PVB brittleness under impact in cold weather below 10 °C.
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Polyvinyl butyral resin Mowital B 45 M is a thermoplastic acetal obtained by acid-catalysed condensation of polyvinyl alcohol with n-butyraldehyde; the polymer chain retains cyclic butyral rings, residual hydroxyl groups and a low concentration of residual acetyl groups. The CAS registry number is 63148-65-2. The degree of acetalisation is controlled because residual hydroxyl groups regulate adhesion to metal oxides, silicates and cellulosic surfaces, while butyral rings depress water uptake and increase solubility in lower alcohols and glycol ethers. The grade designation B 45 M corresponds to a nominal solution viscosity of 45 mPa·s, measured on a 10% by mass ethanolic solution at 20°C under DIN 53015. This value places the resin in the medium-viscosity segment of the Mowital B series, between the lower-viscosity B 30 H and the higher-viscosity B 60 H. Manufacturer data list a residual polyvinyl alcohol content of 20–24 wt%, residual vinyl acetate content not exceeding 2.0 wt%, and a glass transition temperature of approximately 68°C determined by ISO 11357-2. The product is supplied as a white free-flowing powder with a non-volatile content of at least 97% under ISO 3251. These structural parameters govern the balance among solvent solubility, adhesion to polar substrates, film cohesion, and thermal binder removal.
| Property | Typical value for Mowital B 45 M | Measurement basis |
|---|---|---|
| Appearance | White free-flowing powder | Visual |
| Dynamic viscosity of 10% solution in ethanol | 45 mPa·s | DIN 53015, 20°C |
| Residual polyvinyl alcohol content | 20–24 wt% | Manufacturer hydrolysis method |
| Residual vinyl acetate content | ≤2.0 wt% | Manufacturer method |
| Glass transition temperature | 68°C | ISO 11357-2 |
| Non-volatile content | ≥97% | ISO 3251 |
Storage is specified in sealed original packaging at 15–25°C and below 50% relative humidity. The acetal linkage is hydrolytically labile under strongly acidic or strongly alkaline aqueous conditions; exposure to pH below 2.0 or above 10.0 at elevated temperature reduces molecular weight and solution viscosity. Pre-drying is required when the powder has equilibrated above 60% RH, because moisture uptake above 2 wt% interferes with dissolution kinetics and may introduce visible turbidity in ketone-rich solvent blends.
For wash primers and etch primers, Mowital B 45 M is dispersed in ethanol or an ethanol/toluene blend using a high-shear disperser with tip speed of 5–15 m/s; powder wetting is typically complete within 20–60 min at 20–25°C. The dissolution sequence is order-dependent: resin is added to the solvent vortex, not the reverse, and water is introduced last. A sawtooth dissolver with blade diameter equal to 0.3–0.4 of vessel diameter is operated at 500–1,000 rpm until the powder is wetted, then raised to 1,000–2,000 rpm for 30–60 min to eliminate microgels. The resulting solution is filtered through a 20–50 µm bag filter before spray application.
The 10% solution at 20°C exhibits a dynamic viscosity of 45 mPa·s; at 15% solids the system becomes pseudoplastic and is sprayable through conventional air-mix nozzles with orifices between 0.8 mm and 1.4 mm. Toluene is tolerated as a co-solvent, but aliphatic hydrocarbon content above 40% of the solvent blend causes phase separation. Water addition above 10% by volume in ethanol produces turbidity and increases apparent viscosity. In high-humidity application environments, evaporative cooling can lower the film surface temperature below the dew point; blushing becomes probable when relative humidity exceeds 65% unless a slower glycol ether co-solvent is incorporated.
In two-pack wash primers, phosphoric acid is added at 2–5 wt% of the base component to condition steel and aluminium. The acid also catalyses hydrolysis of residual acetyl groups and cyclic acetal linkages. Formulations with pH below 2.0 are therefore mixed shortly before application; after acid addition, pot life is typically restricted to 8–24 h at 20°C. Dried films of 8–12 µm over degreased steel are evaluated for cross-cut adhesion under ISO 2409 and for salt spray resistance under ISO 9227; the latter value is strongly influenced by topcoat type and film thickness, and published data for this specific configuration is limited.
In solvent-borne flexographic and gravure printing inks, B 45 M functions as a film-forming binder for corona-treated polyolefin and polyester substrates. Finished ink formulations typically contain 6–12 wt% B 45 M and are adjusted to a Brookfield viscosity of 15–45 mPa·s at 25°C under ISO 2555. The medium viscosity of this grade provides higher cohesive strength than B 30 H and is selected when lamination bonds are measured under ASTM F88 or DIN 53357; at equal solids, however, its viscosity is lower than that of B 60 H, enabling faster solvent release in high-speed gravure presses. Corona-treated polyethylene terephthalate with wetting tension of 38–42 mN/m is required for stable ink anchorage.
Pigment concentrates are produced on bead mills at 40–50°C using methyl ethyl ketone/ethanol solvent systems; nitrocellulose and thermoplastic polyurethane are common co-binders. In gravure inks, B 45 M is selected where cylinder engraving depths of 30–60 µm and press speeds above 200 m/min demand rapid solvent release without misting. In flexographic inks, the binder is plasticised with 3–7 wt% of resin solids to prevent film cracking on high-elongation polyethylene films. Film tensile extension is evaluated under ISO 527-3 after solvent-cast films are conditioned at 23°C and 50% RH for 48 h. The residual hydroxyl functionality permits crosslinking with polyisocyanate or melamine resins, but amine-based dispersants can accelerate acetal hydrolysis under acidic storage conditions and produce viscosity drift.
The differentiation of B 45 M within the Mowital B series is primarily rheological and thermomechanical. Compared with B 30 H, B 45 M has a higher solution viscosity at the same solids and develops higher tensile strength and elongation in unsupported films; this is used where overcoating stresses in wash primers and ink delamination forces are higher. Compared with B 60 H, B 45 M permits higher solids loading at the same spray viscosity and requires less solvent for viscosity let-down. The intermediate molecular weight also moderates the solvent retention risk seen with high-viscosity PVB grades; residual solvent in 20 µm dry films can be quantified by headspace gas chromatography under ISO 11890-2 and is expected to lie between the values for B 30 H and B 60 H, although published data for this specific configuration is limited.
| Mowital grade | Nominal dynamic viscosity of 10% ethanolic solution at 20°C | Typical formulating response |
|---|---|---|
| B 30 H | 30 mPa·s | Lower solution viscosity, lower cohesive strength, faster solvent release |
| B 45 M | 45 mPa·s | Intermediate viscosity, balance of film toughness and sprayable solids |
| B 60 H | 60 mPa·s | Higher viscosity, higher film cohesion, higher solvent demand |
In good solvents, solution viscosity is not directly proportional to weight-average molecular weight; the Mark–Houwink exponent for polyvinyl butyral in ethanol is close to 0.5–0.8. The moderate increase from B 30 H to B 45 M therefore corresponds to a smaller but significant increase in molecular weight and chain entanglement. The glass transition temperature of the three grades is close to 68°C, so the main differences are not based on dry-film hardness but on solution handling, film formation, and melt-flow behaviour.
Mowital B 45 M is also formulated into solvent-borne temporary masks, laminating films, and plasticised binders when combined with dibutyl sebacate, dioctyl adipate, or triethylene glycol bis(2-ethylhexanoate). Plasticiser demand is governed primarily by residual hydroxyl content and molecular weight; B 45 M requires a lower plasticiser loading than B 60 H to reach a given softening level but more than B 30 H to retain solvent-free film strength. Melt processing on twin-screw extruders with L/D ratios of 25:1 to 40:1 is possible, but the acetal linkage is sensitive to shear heating; melt temperature is kept below 180°C to limit acetic acid evolution and crosslinking. B 45 M exhibits melt-flow behaviour suitable for slot-die coating when plasticised, but published data for this specific configuration is limited.
Mowital B 45 M is used as a non-aqueous tape-casting binder in ceramic green sheet manufacture. In a conventional tape-casting line, ceramic powder, dispersant, B 45 M, plasticiser, and an ethanol/toluene solvent blend are milled in a ball mill or bead mill to a slurry viscosity of 500–3,000 mPa·s at 25°C; the slurry is then cast through a single-slot doctor blade onto a polyester carrier at wet-film thicknesses of 0.1–1.0 mm and carrier speeds of 0.2–1.5 m/min. The residual hydroxyl groups of B 45 M contribute to slip cohesion and green strength, while the acetal backbone decomposes during binder burnout. Thermogravimetric analysis under air at 10°C/min is used to map the decomposition interval; typical PVB oxidative burnout spans 200–400°C, and sintering profiles must allow sufficient oxygen diffusion through porous green tapes to avoid carbon residues.
Operational boundaries are narrow. If the casting solvent contains more than 10% water by volume, slurry viscosity rises and tape surface defects increase. If binder content exceeds 8 wt% of ceramic solids, lamination pressure for multilayer stacks must be raised to maintain interlayer adhesion; if binder content falls below 3 wt%, green tape becomes too brittle for punching and handling. Burnout ramps steeper than 1°C/min through the 250–350°C window can cause blistering in tapes thicker than 300 µm. These thresholds are established on production-scale tape casters with doctor-blade gaps of 0.5 mm and on thermogravimetric analysers calibrated under ISO 11358-1; published data for this specific configuration is limited.
