| HS Code | 118915 |
| Product Name | Mowital B 45 H |
| Chemical Type | Polyvinyl butyral (PVB) |
| Cas Number | 63148-65-2 |
| Appearance | White to off-white powder or granular solid |
| Viscosity 10 Percent Ethanol Solution At 20c | 45 mPa·s |
| Molecular Weight Mw | Approximately 100,000 g/mol |
| Glass Transition Temperature | Approximately 68 °C |
| Density At 20c | 1.1 g/cm³ |
| Refractive Index | 1.488 |
| Hydroxyl Content | 19-22% |
| Butyral Content | 74-78% |
| Acetyl Content | 1-3% |
| Solubility | Soluble in ethanol, methanol, isopropanol, and methylene chloride; insoluble in water |
As an accredited Mowital B 45 H factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Mowital B 45 H is supplied as a free-flowing powder in 20 kg multi-wall paper bags with an inner polyethylene liner. |
| Container Loading (20′ FCL) | Mowital B 45 H loaded in 20′ FCL: dry container, palletized, secured, protected from moisture and heat. |
| Shipping | Mowital B 45 H (polyvinyl butyral resin) ships as a free-flowing powder in sealed multi-layer bags or fiber drums. Protect from moisture, direct sunlight, and high heat. Store away from oxidizing agents. Not classified as dangerous goods under normal transport conditions, but handle with care to minimize dust. |
| Storage | Store Mowital B 45 H in its original, tightly sealed container in a cool, dry, well-ventilated area away from direct sunlight, heat, and ignition sources. Protect from moisture and humidity, as the resin is hygroscopic. Keep containers upright and avoid damage. Under proper conditions, shelf life is typically several years. |
| Shelf Life | Mowital B 45 H shelf life is at least 2 years if stored unopened in cool, dry conditions. |
In solvent-based flexographic surface inks for corona-treated biaxially oriented polypropylene (BOPP) and polyethylene terephthalate (PET) packaging films, Mowital B 45 H is incorporated as a secondary film-forming binder to raise polar adhesion, improve pigment redispersion, and reduce nitrocellulose brittleness. A typical letdown contains 5–8 wt% Mowital B 45 H based on total liquid ink, alongside 3–6 wt% nitrocellulose, 1–3 wt% polyurethane or ketone resin, and 35–45 wt% ethanol/ethyl acetate solvent. The resin is pre-dissolved at 25–30 °C in a 70:30 ethanol/ethyl acetate mixture using a low-shear propeller at 200–400 r/min for 60–90 min. Dry resin added directly to a high-speed Cowles disperser can form hard agglomerates and generate excessive shear heat, producing viscosity drift and batch-to-batch press-side variation. Batch viscosity of a 10 wt% ethanol solution is normally read in the 40–60 mPa·s range at 20 °C from the certificate of analysis. Ink fineness of grind after letdown is checked by ISO 1524:2013, with a typical grind gauge reading below 15 μm for surface printing. Film adhesion depends on corona treatment above 38 dyn/cm as tested by ASTM D2578-17. Below 36 dyn/cm, tape-release failures are commonly observed on polypropylene. The addition level is adjusted to maintain press viscosity at 18–25 s by ISO 2431:2019 cup 3 at 25 °C and to avoid foaming on a central impression press running at 200–350 m/min with chambered doctor blades. Amine-based surfactant packages should be avoided because alkaline conditions accelerate acetal hydrolysis and cause viscosity drift over 72 h storage. End products are typically printed snack wrappers, confectionery films, and outer webs of duplex or triplex laminations where the ink does not directly contact food.
The pot life of a two-pack acid-catalyzed wash primer is determined primarily by the ratio of phosphoric acid to Mowital B 45 H binder and by the water content of the acid component. A starting base component contains 7–9 wt% Mowital B 45 H, 4–6 wt% zinc phosphate inhibitor pigment, 1–2 wt% talc, 60–65 wt% isopropanol, and 15–20 wt% n-butanol. The matching acid component contains 10–15 wt% phosphoric acid 85%, 3–5 wt% deionized water, and 80–85 wt% isopropanol. The two components are mixed at 4:1 by volume immediately before application, giving a pot life of 8–24 h at 23 °C. Application is performed by pressure-pot air spray with a 1.4–1.8 mm nozzle, atomization pressure 0.3–0.5 MPa, and fan air pressure 0.2–0.3 MPa, applied over steel prepared to Sa 2½ under ISO 8501-1. Dry film thickness is held between 8 µm and 15 µm. Above 15 µm, the phosphoric acid content per unit area rises and intercoat delamination becomes more frequent under humidity cycling. Adhesion after a 24-h cure is checked by cross-cut to ISO 2409:2020, with class 0 expected on grit-blasted steel. Salt spray resistance is evaluated under ISO 9227:2022, but the primer alone is not intended for long-term exposure without an approved intermediate and topcoat. Chromium(VI)-containing pigments are restricted under REACH Annex XIV; zinc phosphate versions are used where Cr(VI) is prohibited. Published data for Mowital B 45 H specifically in SSPC-Paint 27 wash primers is limited, so formulation adjustments should be validated on the actual blast-cleaned surface. Typical terminal components include ballast tank linings, coastal structural steel, and aircraft structural primers where a thin pretreatment layer improves topcoat adhesion.
Slurry preparation for alumina tape casting uses Mowital B 45 H in an ethanol/toluene solvent pair with a phthalate plasticizer and a phosphate ester or fish-oil dispersant. For 100 parts by weight of calcined alumina powder, a workable starting formulation is 9–12 parts Mowital B 45 H, 3–5 parts dibutyl phthalate or benzyl butyl phthalate, 0.5–1.2 parts dispersant, and 45–60 parts of an ethanol/toluene 68:32 solvent blend. The resin is dissolved before ceramic powder addition to avoid binder-rich regions that produce lamination defects in the green tape. Milling is carried out in a ceramic-lined ball mill with 5 mm yttria-stabilized zirconia media for 18–24 h at 40–60% of critical speed, followed by de-airing under 0.08–0.095 MPa vacuum to remove trapped air. The slurry is cast onto a stainless steel or PET carrier with a doctor blade gap of 0.3–1.2 mm and a carrier speed of 0.2–1.0 m/min. Drying in a two-zone tunnel at 60–80 °C reduces residual solvent to below 0.5 wt% before green sheet cutting. Storage relative humidity above 60% RH can be absorbed by the tape and shift lamination moisture, so controlled humidity is required. Binder burnout in air is programmed at 1–2 °C/min to 500 °C with a 1-h hold. PVB decomposition occurs broadly between 200 °C and 450 °C, and the burnout schedule must be matched to tape thickness to avoid cracking or carbon residue. Residual carbon contents below 0.05 wt% are commonly targeted for multilayer ceramic capacitors. Process solvent consumption is evaluated under the EU Solvent Emissions Directive 2010/75/EU. Terminal products include alumina substrates for power electronics and low-temperature co-fired ceramic tapes for RF modules.
Heat-seal coatings for aluminum lidding foil represent a lower-viscosity route in which Mowital B 45 H is blended with vinyl acetate copolymers or acrylic resins to achieve peelable or permanent seals on polystyrene, polypropylene, and PVC cups. The PVB addition level is commonly 15–30 wt% of coating solids, with total dry film weight on hard-tempered foil between 3 g/m² and 6 g/m². The lacquer is applied by a gravure cylinder with 45–60 lines/cm and a cell volume of 12–16 cm³/m² at 150–200 m/min, then dried through a 60–100 °C tunnel with solvent recovery. Heat sealing is performed at 110–140 °C under 0.4–0.6 MPa for 0.5–1.0 s, depending on cup material and coating weight. Seal strength is measured by ASTM F2029-16. Dairy lidding commonly specifies a minimum seal strength of 4 N/15 mm at the chosen seal condition. The PVB resin improves bond to polar cup surfaces and lowers the seal initiation temperature relative to a pure vinyl acetate copolymer. High-temperature retort processes above 121 °C are outside the reliable operating window because PVB softens and seal strength decays under steam pressure. Indirect food-contact status is supported when the aluminum foil acts as a functional barrier under FDA 21 CFR 175.300 or 175.105, or EU Regulation 10/2011, provided migration testing confirms the barrier properties. Terminal products include yogurt cup lids, cream cheese tub lids, and coffee capsule lidding films.
In vinyl-butyral-phenolic film adhesives for aluminum alloy sheet joining, Mowital B 45 H acts as a high-hydroxyl film-forming modifier that plasticizes the cured phenolic network and raises room-temperature peel strength. Typical formulation mass ratios are 20–40 parts PVB to 100 parts resole phenolic solids, with 5–15 parts aluminum powder filler or calcium silicate filler depending on thermal conductivity and film density. The film is coated from an ethanol/MEK solution, dried to a solvent-free tacky film, and cured under 0.35–0.7 MPa pressure at 150–170 °C for 30–60 min in an autoclave or heated platen press. Single-lap shear strength of the bonded assembly is evaluated by ASTM D1002 and floating-roller peel resistance by ASTM D3167. The cured adhesive performs best below 120 °C continuous service. Above this temperature, PVB softens and lap shear values decrease. Amine-based epoxy adhesive systems are generally incompatible with PVB at elevated temperature because primary amines can react with acetal groups and produce embrittled interfaces. Published data for Mowital B 45 H in this specific structural film configuration is limited. Existing PVB-phenolic historical systems suggest the formulation space, but component qualification must be repeated on the actual aluminum alloy and surface treatment. Terminal applications include secondary aircraft structures and interior sandwich panel bonding where peel performance and vibration damping are more critical than maximum hot-wet shear strength.
When flat glass processing lines require temporary protection during sandblasting, grinding, or drilling, Mowital B 45 H is applied from an alcohol-based solution as a tough, water-resistant masking film that can be removed by solvent wiping. A typical composition contains 10–15 wt% Mowital B 45 H in ethanol or isopropanol, 5–10 wt% phthalate plasticizer based on resin solids, and 1–2 wt% release agent or silicone surface modifier. The solution is applied by spray or flood coating to form a dry film thickness of 15–25 µm after air drying at 20–25 °C for 15–20 min. The film withstands airborne alumina grit at 0.2–0.4 MPa blasting pressure and resists water-based cutting fluids but remains removable with ethanol or ethyl acetate. Solvent recovery and workplace exposure limits are evaluated under the EU Solvent Emissions Directive 2010/75/EU and national occupational exposure limits. The coating must not be applied to acrylic or polycarbonate sheets because the alcohol solvent attacks the substrate surface and causes stress cracking. End products include architectural glass panels, automotive windshield components before PVB interlayer lamination, and decorative sandblasted glass where uncut areas require temporary protection.
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Mowital B 45 H is a plasticizer-free polyvinyl butyral resin supplied as a white, free-flowing powder for solvent-borne binder applications requiring controlled solution viscosity, polar adhesion, and high film toughness. The grade is positioned between lower-viscosity Mowital B 30 H and higher-viscosity Mowital B 60 H in the polyvinyl butyral product range. Typical release data from the manufacturer list a dynamic viscosity of 45–55 mPa·s for a 10 wt% solution in anhydrous ethanol at 20 °C determined in accordance with DIN 53015. Polyvinyl alcohol content is specified within 20.0–24.0 wt%, while polyvinyl acetate content is limited to ≤2.0 wt%. Unplasticized glass transition temperature measured by differential scanning calorimetry to ISO 11357-2 is approximately 70 °C. Because the resin contains no external plasticizer, film softness and elastic recovery derive from the butyral side groups and residual hydroxyl moieties rather than from a migrating additive.
Specification data and corresponding control methods are summarized in Table 1. The limits represent manufacturer release values and are not end-use performance specifications. Viscosity is measured after complete dissolution in anhydrous ethanol; residual water in the solvent raises apparent viscosity through hydrogen bonding and can shift results above the upper limit.
| Property | Method | Typical limit |
|---|---|---|
| Non-volatile content | ISO 3251 | ≥97.5 wt% |
| Dynamic viscosity, 10 wt% in anhydrous ethanol | DIN 53015 | 45–55 mPa·s |
| Polyvinyl alcohol content | DIN 53240 | 20.0–24.0 wt% |
| Polyvinyl acetate content | Internal hydrolysis titration | ≤2.0 wt% |
| Ash content | ISO 3451-1 | ≤0.1 wt% |
| Bulk density | DIN EN ISO 60 | 0.25–0.35 g/cm³ |
| Glass transition temperature, unplasticized | ISO 11357-2 | approximately 70 °C |
Mowital B 45 H dissolves readily in methanol, ethanol, 96% ethanol, isopropanol, methyl ethyl ketone, cyclohexanone, glycol ethers, and selected ester/alcohol blends. It is insoluble in aliphatic hydrocarbons, water, and most plasticizer oils at room temperature. Industrial solvent mixtures include ethanol/toluene blends at 70:30 to 80:20 mass ratios, methyl ethyl ketone/toluene blends at 60:40, and ethanol/ethyl acetate blends at 70:30. Water concentrations above 3–5 wt% of the solvent mixture produce cloud points and viscosity increases; anhydrous or 96% ethanol is therefore preferred for viscosity control.
Powder dissolution should be performed with a high-shear disperser rather than a simple paddle stirrer. The resin is added gradually to the vortex at 20–30 °C; after a wetting phase of 10–15 min, the batch is heated to 40–50 °C under shear until all particles disappear. Extended exposure above 60 °C can induce acetal hydrolysis and discoloration, particularly when acidic adhesion promoters are already present. Final filtration through 25–50 µm bag filters removes undispersed gel particles. Solution viscosity is shear-thinning above 100 s⁻¹; at gravure and flexographic coating shear rates between 10⁴ s⁻¹ and 10⁵ s⁻¹, apparent viscosity drops sufficiently for chambered doctor blade delivery.
| Grade | Nominal viscosity at 10 wt% in ethanol, 20 °C | Viscosity class | Processing consequence |
|---|---|---|---|
| Mowital B 30 H | 30–40 mPa·s | lower | higher solids at equal coating viscosity; thinner film build |
| Mowital B 45 H | 45–55 mPa·s | medium-high | balanced film strength and application viscosity |
| Mowital B 60 H | 60–70 mPa·s | high | maximum cohesive strength; increased solvent demand |
At equal binder solids, B 45 H produces higher solution viscosity than B 30 H and lower solution viscosity than B 60 H. In solvent-borne laminating adhesives for polyester and aluminum foil structures, this positions B 45 H for dry coat weights between 2 µm and 6 µm on high-speed coating heads without excessive solvent addition. The higher chain length relative to B 30 H improves room-temperature T-peel strength when tested according to ASTM D1876; the lower chain length relative to B 60 H reduces viscosity growth during batch ageing. Glass transition temperature differences among the three grades are small; all lie between 68 °C and 72 °C when measured unplasticized by DSC to ISO 11357-2. The controlling difference is therefore chain length and solution viscosity, not glass transition temperature.
In metal pretreatment primers based on phosphoric acid and zinc tetroxychromate, Mowital B 45 H functions as the film-forming binder that binds the phosphate reaction layer to steel and aluminum surfaces. A typical working formulation contains 7–12 wt% B 45 H solids, 2–4 wt% phosphoric acid, and 8–12 wt% zinc tetroxychromate in a mixed alcohol/toluene solvent system. After dry film application at 8–12 µm, cross-cut adhesion to cold-rolled steel is assessed according to ISO 2409; published comparable systems typically achieve classification 0–1 on 25 mm grid test panels. The acid-catalyzed cleavage of the butyral ring limits pot life; pre-acidified single-pack wash primers are therefore consumed within 4–8 h at 25 °C, and automated lines inject phosphoric acid immediately before the spray header to avoid viscosity drift. Published data for the long-term acidified storage stability of B 45 H specifically is limited.
In flexographic and gravure surface-printing inks for corona-treated polyolefin and polyester films, B 45 H is introduced as a co-binder at 3–10 wt% of total ink. The grade increases alcohol solubility and pigment wetting in ethanol/ethyl acetate formulations and raises the softening point of the dried ink film compared with low-viscosity grades. Tape-adhesion testing on low-density polyethylene film follows ASTM F2252; corona discharge pre-treatment to 38–42 mN/m surface energy is required. At a constant pigment-to-binder ratio, substituting B 45 H for a 30–40 mPa·s grade typically permits a reduction in resin content of 1–2 wt% without loss of lamination bond strength, because the higher molecular weight contributes cohesive film strength at dry film thicknesses below 1.5 µm. Drying tunnels for PVB-based inks are zoned at 40–60 °C and 60–80 °C; maximum web temperature is held below 80 °C to prevent blocking.
B 45 H is used as a thermoplastic binder in non-aqueous tape-casting slurries for alumina substrates and barium titanate multilayer devices. Representative slurry compositions contain 55–65 wt% ceramic powder, 8–13 wt% B 45 H, 2–5 wt% plasticizer, and the balance methyl ethyl ketone/ethanol azeotrope. Ball milling in porcelain-lined vessels at 30–50 rpm for 18–24 h disperses the ceramic and dissolves the binder; vacuum de-airing at 50–100 mbar removes entrapped air. Tape is cast through a doctor blade gap of 0.5–1.5 mm, dried, and wound into rolls. Green tensile strength and elongation are influenced by the 20.0–24.0 wt% polyvinyl alcohol content; higher hydroxyl content increases green density and lamination strength but also increases moisture uptake. Published data for the exact green-strength retention of B 45 H under high-humidity tape-casting atmospheres is limited; controlled rooms at 20–25 °C and 40–50% RH are commonly specified.
Lamination of stacked green sheets is performed at 70–90 °C and 15–25 MPa. Defects such as binder squeeze-out or layer delamination result when binder molecular weight is too low. B 45 H resists squeeze-out at the upper pressure range because its higher chain entanglement raises zero-shear viscosity in the plasticized state. Binder burnout is performed in air at 0.5–1.0 K/min with a soak at 450–550 °C, leaving ash below 0.1 wt%.
For plasticized PVB sheet used in laminated safety glass interlayers, B 45 H is compounded with 20–30 phr of triethylene glycol bis(2-ethylhexanoate) plasticizer in a co-rotating twin-screw extruder with an L/D ratio of 44–52; barrel temperatures are maintained from 150 °C to 190 °C and melt temperature is kept below 220 °C. Extruded sheet is evaluated for impact performance and laminate adhesion under ISO 12543-2. The higher molecular weight of B 45 H relative to B 30 H improves energy transfer and tear resistance after autoclave lamination at 135–145 °C and 1.1–1.3 MPa, but increases extruder drive load. Lower-viscosity grades are selected when film thickness below 0.38 mm is required or when extrusion backpressure exceeds the die limit.
Regulatory classification is not a performance property, but in the EU the resin is assessed under REACH Regulation (EC) No 1907/2006. The polymer is exempt from registration, while constituent monomers must be registered. Users evaluating indirect food contact adhesives or printing inks must confirm compliance with 21 CFR 175.105, 21 CFR 175.300, or applicable national legislation.
B 45 H powder is hygroscopic because of the residual polyvinyl alcohol content. Storage in sealed original containers below 30 °C and below 60% RH minimizes caking. If moisture content exceeds 1.5 wt%, drying in a fluidized-bed dryer at 40–50 °C for 2–4 h is recommended before dissolution. The powder forms combustible dust-air mixtures; electrical equipment and grounding arrangements are specified under IEC 60079-10-2 zone classification and EN 1127-1. Open flames and hot surfaces above 180 °C must be avoided in dust-laden areas. The resin is incompatible with concentrated oxidizing agents, strong mineral acids at elevated temperature, and amine-based epoxy hardeners that can react with hydroxyl groups and advance crosslinking before film formation.
