| HS Code | 578230 |
| Product Name | Mowital B 20 H |
| Chemical Family | Polyvinyl butyral (PVB) |
| Chemical Name | Polyvinyl butyral |
| Physical Form | White granules |
| Odor | Mild, characteristic |
| Viscosity 5 In Ethanol 20 C | ~20 mPa·s |
| Butyral Content | ~70-75% |
| Hydroxyl Content | ~25-30% |
| Acetate Content | ~1-3% |
| Molecular Weight Mw | ~150,000 g/mol |
| Density 20 C | ~1.1 g/cm³ |
| Bulk Density | ~500-800 kg/m³ |
| Refractive Index | ~1.49 |
| Glass Transition Temperature | ~70°C |
| Solubility | Soluble in alcohols, ketones, esters; insoluble in water |
| Water Absorption | ~1-2% |
As an accredited Mowital B 20 H factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Mowital B 20 H is supplied as a free-flowing powder in 20 kg moisture-protected bags, palletized for safe transport and storage. |
| Container Loading (20′ FCL) | 20′ FCL: Mowital B 20 H packed on pallets, secured and stowed in a standard 20-foot container for safe transport. |
| Shipping | Mowital B 20 H, a polyvinyl butyral resin, ships as a non-dangerous, free-flowing powder in moisture-protective bags or drums. It is not regulated as hazardous under ADR, IMDG, or IATA. Protect from moisture and dust accumulation; store in a cool, dry, well-ventilated area away from ignition sources. |
| Storage | Store Mowital B 20 H in its original, tightly sealed container in a cool, dry, well-ventilated area. Protect from moisture, direct sunlight, and high temperatures. Keep away from open flames, sparks, and incompatible materials. Ensure good ventilation and maintain moderate humidity to prevent clumping or degradation during storage. |
| Shelf Life | Shelf life of Mowital B 20 H is typically 2 years when stored unopened in a cool, dry place. |
Mowital B 20 H enters multilayer ceramic capacitor tape casting as the primary thermoplastic binder during the second stage of nonaqueous slurry preparation. The ceramic powder is initially milled with a solvent blend of ethanol and toluene and a phosphate ester dispersant until the BaTiO3 particles reach a D50 below 1.2 µm, because the polymer binder cannot break hard agglomerates. After high-shear dispersion, Mowital B 20 H is added as a 20–25 wt% solution in ethanol and mixed under low shear to avoid molecular weight degradation. Binder loadings of 7–10 parts per 100 parts ceramic powder provide sufficient green strength for punching, via filling, and layer stacking while remaining removable under the long debinding schedules used in MLCC production. Slurry viscosity after deaeration is normally held between 2,000 and 5,000 mPa·s at a shear rate of 20 s⁻¹ by adjusting free solvent and binder content; higher viscosity reduces wetting of the polyester carrier, while lower viscosity causes particle settling within 2 h. The slurry is applied through a doctor blade with a gap of 100–250 µm onto a silicone-coated PET carrier at casting speeds of 0.3–2.0 m/min, followed by multizone drying at 40 °C, 60 °C, and 80 °C to avoid skinning. Dry green tape thickness typically falls between 20 µm and 150 µm depending on gap and solids content. The cast tape is inspected for pinholes, thickness variation below ±2 µm across a 300 mm web, and residual solvent below 1 wt% before layer registration. During co-firing, the PVB decomposes in air between 200 °C and 550 °C; a heating ramp of 0.5–1.0 °C/min through the 200–450 °C window minimises carbon residue and prevents blisters or delamination. The low ash content of Mowital B 20 H, combined with complete burn-out, is critical because residual carbon above 0.05 wt% can reduce insulation resistance in fired MLCC bodies. Published formulation data specific to Mowital B 20 H is limited, but the viscosity specification of 20 mPa·s as a 10 wt% ethanol solution per DIN 53015 makes it compatible with high-solids slurry designs where higher-viscosity grades require excessive solvent addition and extend drying time.
Table 1. Representative nonaqueous tape-casting composition for BaTiO3 dielectric layers.
| Component | Parts by weight | Function |
|---|---|---|
| BaTiO3 powder, D50 0.8–1.0 µm | 100.0 | Dielectric phase |
| Ethanol/toluene 70:30 blend | 40.0–55.0 | Solvent carrier |
| Mowital B 20 H | 7.0–10.0 | Thermoplastic binder |
| Dibutyl sebacate | 2.0–4.0 | Plasticizer |
| Phosphate ester dispersant | 0.5–1.2 | Particle dispersant |
On cold-rolled steel and hot-dip galvanized surfaces, a two-package wash primer built on Mowital B 20 H functions as an acid-etch adhesion promoter rather than as a barrier coat. In the base component, the resin is dissolved at 6–8 wt% in a mixture of isopropanol and n-butanol, with zinc phosphate or zinc chromate as the active pigment and a small amount of talc to control settling. The acid component is typically 85% phosphoric acid diluted with isopropanol and water; the two components are mixed by volume at a base-to-acid ratio of 4:1 just before spray application. Once mixed, the pot life is limited by acid-catalysed degradation of the PVB chain at the acetal linkages and by acid consumption on the metal surface, so a practical pot life of 4–8 h at 20–25 °C is expected; viscosity rise and loss of adhesion are observable beyond that window. Spray application uses conventional air-atomising equipment with a fluid nozzle pressure of 0.15–0.3 MPa and a dry film thickness of 5–8 µm. Film builds above 12 µm should be avoided because the acid-catalysed matrix remains brittle and can cause cohesive failure under a topcoat. The primer should be topcoated after 30–60 min and within 8 h with an epoxy or polyurethane system to prevent underfilm corrosion at the interface. In EU applications, zinc chromate is restricted under REACH Annex XVII entry 16 for certain uses, which has shifted many lines to zinc phosphate or organically modified zinc orthophosphate; the replacement alters both the acid demand and the required PVB content. Salt-spray resistance is commonly assessed according to ISO 9227 with scribe creep values dependent on topcoat chemistry; published data specific to a Mowital B 20 H wet primer without topcoat is limited.
A solvent-borne rotogravure ink vehicle based on Mowital B 20 H typically operates in an alcohol–ester solvent blend where nitrocellulose or cellulosic resins alone fail to provide adequate pigment wetting and substrate adhesion. A starting vehicle contains 8–12 wt% Mowital B 20 H, 35–50 wt% mixed solvent, and 15–25 wt% pigment, with plasticizer at 2–5 wt% of resin solids to adjust film flexibility. The solvent fraction is balanced among ethanol, ethyl acetate, and methoxypropanol or butyl acetate; ethyl acetate reduces viscosity at press, methoxypropanol retards surface drying and improves levelling on non-porous films, and residual ethanol content must remain below the limit specified for the print line’s VOC abatement system. Finished ink viscosity is controlled at 16–24 s Zahn cup #3 at 25 °C for gravure engraving depths of 30–60 µm. Drying tunnels operate at 60–90 °C with impingement air velocities above 15 m/s, and residual solvent in the dried ink film should be below 1 mg/m² in food packaging structures before lamination. In retort applications at 121 °C for 30–60 min, the PVB binder contributes heat resistance but must be combined with a crosslinker such as a blocked isocyanate or melamine resin at 3–6 wt% of total solids to avoid film softening and delamination. Adhesion and lamination bond strengths are checked by peel testing under ASTM D1876 or ISO 11339; acceptable values depend on substrate and laminate construction, and field quality control often rejects bond strengths below 2.5 N/15 mm. For food-contact printed laminates, compliance is established through migration testing under Regulation (EU) No 10/2011 if the ink is behind a functional barrier, or through 21 CFR 175.105 for the adhesive/coating layer; residual butyraldehyde from incomplete acetal formation must be below its specific migration limit. The operational boundary of Mowital B 20 H in solvent ink is water tolerance. Adding more than 3–5 wt% water to the solvent blend can cause resin precipitation or rapid viscosity rise, especially in low-ester blends.
When a non-tacky transfer adhesive is required for bonding aluminium foil to PET or for attaching films to glass in a secondary lamination step, Mowital B 20 H can be solvent-cast into a heat-seal layer at 15–20 wt% solids in a ketone/alcohol blend. The casting solution is applied to a release-treated PET liner by comma doctor or slot die at wet film thicknesses of 80–150 µm and dried through a three-zone oven at 50 °C, 70 °C, and 90 °C to avoid plasticizer exudation. The dried adhesive film, typically 20–60 µm thick, is then transferred to the primary web or supplied as a supported interlayer. Plasticizer loading between 10 phr and 25 phr based on resin is commonly used to shift the heat-seal initiation temperature downward; ester plasticizers such as dioctyl adipate reduce the effective glass transition temperature while increasing low-temperature flexibility. Sealing is performed at 120–180 °C, 0.2–0.5 MPa, and 1–5 s dwell in a flatbed or rotary press. Because Mowital B 20 H retains hydroxyl functionality, it bonds to oxidised metal surfaces and glass, but it also absorbs atmospheric moisture; film conditioned at 23 °C and 50% relative humidity may take up 2–4 wt% water, and pre-drying at 40–50 °C for 2–4 h is recommended before sealing when bubble-free bonds are required. Peel strength after sealing is measured according to ASTM D1876 or ISO 10283 depending on the substrate; typical quality limits are controlled by the converter rather than derived from the resin specification. The main incompatibility is with amine-catalysed two-component adhesives in adjacent layers: free amines can accelerate ester plasticizer hydrolysis and should be separated by a barrier film if co-laminated.
Glass-fabric prepregs for phenolic laminates incorporate Mowital B 20 H at 5–12 wt% of total solids to reduce prepreg brittleness and improve fiber wet-out. The resin mix is prepared by dissolving B 20 H in ethanol or methoxypropanol before addition to the aqueous resole to prevent precipitation; a solvent blend containing at least 20–30 wt% alcohol is typical. Glass fabric is impregnated to a resin pick-up of 40–55 wt% and passed through a vertical or horizontal treater with drying zones set at 100–130 °C. The target volatile content before lay-up is 2–5 wt%, because excess solvent or water causes steam porosity during press cure. Laminates are pressed at 145–160 °C and 0.8–1.5 MPa for 20–40 min depending on panel thickness. In the cured matrix, PVB is not fully inert: the residual hydroxyl groups can react with methylol groups of the resole at press temperature, so the modifier contributes to the network rather than existing only as a discrete phase. This behaviour reduces the risk of phase-separation-induced opacity compared with non-reactive thermoplastics. The use temperature and dielectric performance depend on cure state and PVB content; quantitative dielectric and flexural data specific to Mowital B 20 H in phenolic prepregs is limited, so comparative testing under ASTM D790 and IEC 60243 is required for electrical applications. The main processing constraint is the upper cure temperature of the resole: above 160 °C, the PVB molecular weight is sufficient to resist flow, but prolonged exposure can cause yellowish discolouration, making the material unsuitable for naturally coloured decorative laminates.
For laminated safety glass production, the film-forming function of Mowital B 20 H is realised after plasticization, casting or extrusion, and controlled moisture conditioning. The resin is combined with 20–32 phr of a plasticizer such as triethylene glycol bis(2-ethylhexanoate) or dibutyl sebacate, a UV absorber, an antioxidant, and an adhesion control salt to produce a film with a glass transition temperature between 25 °C and 30 °C after plasticization. Film production requires careful moisture control because PVB equilibrates with ambient humidity; interlayer film is normally conditioned to a moisture content of 0.4–0.6 wt% before lamination to match the target adhesion level. Glass sandwich panels are assembled in a clean room at 18–22 °C and 20–30% relative humidity, then deaired by vacuum bag or nip roller. The autoclave step is conducted at 120–150 °C and 0.8–1.5 MPa for 30–90 min depending on glass thickness and load size. Adhesion is verified according to EN ISO 12543-4 or equivalent national standards, with pummel adhesion and peel values controlled by the specific glass surface treatment and adhesion promoter concentration. Mowital B 20 H with a nominal solution viscosity of 20 mPa·s in 10 wt% ethanol gives lower melt viscosity during processing than higher-viscosity grades, which can reduce lamination pressure requirements but may require a higher molecular weight plasticizer to maintain creep resistance at elevated service temperatures. Use in automotive windshield applications requires full compliance with ECE R43 or FMVSS 205; use in architectural laminated glass requires compliance with EN ISO 12543 and applicable national building codes. The main limitation is long-term plasticizer migration into adjacent edge sealants; only validated low-uptake sealants should be specified.
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A polyvinyl butyral resin of the medium-viscosity segment, Kuraray Mowital B 20 H is supplied as a white free-flowing powder and is used predominantly in ethanol-borne coatings, wash primers, flexographic inks, ceramic green-sheet binders, and heat-seal lacquers. The grade belongs to the Mowital B series, in which the numeric designation places Mowital B 20 H between lower-viscosity grades such as Mowital B 16 H and higher-viscosity grades such as Mowital B 30 H. That intermediate position provides a practical compromise between solution solids at spray viscosity and the cohesive strength of the dried film. Batch-release data for this grade include residual polyvinyl acetate at 2.5% maximum and ash at 0.05% maximum. The 10% solution in ethanol at 20°C is normally specified by falling-ball viscometer according to DIN 53015; exact upper and lower limits should be taken from the current certificate of analysis.
Solubility is highest in polar oxygenated solvents: ethanol, n-propanol, isopropanol, methyl ethyl ketone, and glycol ether acetates. Aliphatic hydrocarbons and water are non-solvents. In industrial dissolution practice, a high-torque dissolver with a peripheral tip speed of 10–15 m/s is used; pre-drying is recommended when warehouse relative humidity exceeds 60% because absorbed moisture retards dissolution and can increase haze. The resin is not a plasticized grade; blending with external plasticizers such as dibutyl sebacate or triethylene glycol bis(2-ethylhexanoate) shifts peel adhesion and low-temperature flexibility. Published data for plasticizer limits in Mowital B 20 H wash-primer configurations is limited; qualification trials are required to set upper plasticizer dosage above 15 wt% on resin solids.
Within the Mowital B series, the B 20 H designation indicates a medium position with respect to solution viscosity and molecular weight. At equal solids content in ethanol, B 20 H produces higher viscosity than B 16 H and lower viscosity than B 30 H. The corresponding film properties follow the same order: B 16 H yields softer film with faster solvent release; B 30 H yields greater tensile strength and blocking resistance; B 20 H provides a balance where the coating must wet metal surfaces and still withstand handling after drying. The dry resin has a glass transition temperature of approximately 66°C when measured by differential scanning calorimetry according to ISO 11357-2:2020.
In two-component wash primers, Mowital B 20 H is dissolved in ethanol or an alcohol-ketone blend at 10–15 wt% solids and combined with zinc tetroxychromate or zinc phosphate pigment pastes. Phosphoric acid at 0.5–1.5 wt% on total formula is added as an adhesion promoter and metal-surface conditioner. The acid etches the oxide layer on steel and aluminium, but its presence accelerates hydrolysis of the polyvinyl butyral backbone if the pre-mix is stored above 25°C or for more than 24 h. Production-scale experience on airless spray lines with 30:1 pumps and tip orifices of 0.28–0.38 mm shows that viscosity loss precedes visible flocculation; therefore the acid is added only as the final component, with continuous low-shear agitation rather than high-shear dispersing.
Dry film performance is assessed using ASTM B117-19 salt spray exposure on zinc-phosphated steel. Coatings based on Mowital B 20 H are typically evaluated at dry film thicknesses of 8–15 µm; cross-hatch adhesion before and after humidity exposure is measured according to ISO 2409:2013. Because PVB has good adhesion to bare metal but limited barrier resistance at thicknesses below 8 µm, the formulation window is narrow: an increase in phosphoric acid to above 1.5% on total formula improves initial wetting but increases moisture uptake and can cause blistering under salt spray. A decrease below 0.5% reduces acid etching and lowers adhesion on untreated aluminium. The operational boundary is therefore tighter than for many epoxy or polyurethane primers.
Humidity exposure testing according to ISO 6270-2:2018 is used to detect residual phosphate crystals at the primer-substrate interface. In one failure mode observed on an automatic reciprocating spray line, droplet size variation caused localised acid concentration in the wet film, producing soft spots after 72 h condensation exposure. The corrective action was to increase atomising air pressure to maintain a wet-film thickness standard deviation below 1.5 µm across a 600 mm panel. Such field data define the practical process window for Mowital B 20 H wash primers more reliably than dip-coat trials alone.
| Qualification method | Standard/test | Representative production control target |
|---|---|---|
| Cross-cut adhesion on cold-rolled steel | ISO 2409:2013 | ≤ class 1 at 10 µm dry film |
| Salt spray scribe creep | ASTM B117-19 | ≤ 3.0 mm after 500 h |
| Humidity resistance | ISO 6270-2:2018 | No blistering at 240 h |
| Flexibility on tinplate | ISO 1519:2011 | No cracks on 3 mm mandrel |
Mowital B 20 H is often used as a modifying resin in coatings where it provides rapid physical drying and metal adhesion. It is not a reactive crosslinker and does not enter the epoxy-amine curing network. When combined with amine-based hardeners, the acidic acetal hydrolysis products generated at elevated temperatures can accelerate corrosion of aluminium packaging and can interfere with epoxy conversion. Users should avoid prolonged staging of PVB-modified epoxy primers with amine hardeners above 40°C because batch gel time can shift unpredictably. The incompatibility is not visual immediately; a two-component clearcoat can appear homogeneous at mixing and then exude droplets after 48 h at 23°C. This exudate is mainly unreacted epoxy and plasticiser, identifiable by Fourier-transform infrared spectroscopy using ASTM E1252-98(2021) as the sampling guide.
In polyisocyanate systems, the residual hydroxyl groups in Mowital B 20 H can react with the isocyanate crosslinker at room temperature. This is beneficial for chemical resistance but can shorten pot life. When the PVB content exceeds 10 wt% on binder solids in a two-component acrylic polyol clearcoat, the concentration of available hydroxyl from PVB plus acrylic resin changes the NCO:OH ratio and may require recalculation. Production-scale mixing equipment with variable-speed propellers at 500–1,000 rpm is sufficient for dispersion, but degassing under vacuum at 50 mbar is recommended to avoid micro-foam that raises film haze above 1%.
In ethanol-based flexographic inks for corona-treated polyethylene and untreated polypropylene, Mowital B 20 H is normally pre-dissolved at 25–30% solids in ethanol with a small addition of ethyl acetate, then let down into nitrocellulose or maleic-modified rosin vehicles. A chamber-doctor blade system with an anilox roll of 180–300 lines/cm and cell volume of 10–18 cm³/m² operates within a press viscosity of 18–25 s on a ISO 2431:2019 flow cup with 4 mm orifice. Mowital B 20 H is selected over B 16 H when higher cohesive strength and reduced blocking on reverse-printed film are required; it is selected over B 30 H when the press must retain higher pigment load without solvent additions that lower viscosity.
Adhesion to treated film is checked according to ISO 2409:2013 and tape-off using a pressure-sensitive tape specified by ASTM D3359-17. The resin itself does not contain slip additives, and printed film coefficient of friction is modified by the ink’s wax dispersion. Solvent retention is controlled by the drying hood profile: a three-zone dryer at 50°C, 60°C, and 70°C reduces residual ethanol below 0.5 mg/m² after 1.5 s residence time on a central-impression press running at 120 m/min. That profile is equipment-specific; alternative press speeds require recalculation of the ratio of solvent release to film formation.
In multilayer ceramic capacitor tape casting, Mowital B 20 H is used as a temporary binder for barium titanate and other dielectric powders. The tape formulation uses a solvent mixture of ethanol and toluene or methyl ethyl ketone; the powder-to-binder ratio is usually 100:15–25. A doctor blade gap of 0.2–0.5 mm and casting speed of 0.5–2.0 m/min are typical on continuous lines. The critical process conflict is oxidative burnout: the polymer must leave no conductive carbon residue in the ceramic matrix. Thermogravimetric analysis at 10 K/min under air according to ISO 11358-1:2014 is used to profile decomposition through 250–450°C. If the ramp rate through this window exceeds 3 K/min, residual carbon can rise above 0.1% in dense tapes. Lower-viscosity PVB grades may allow higher solids but reduce green strength; higher-viscosity grades improve green strength but demand slower debinding and can leave more residue if kiln residence time is not adjusted. Mowital B 20 H is selected where green tape with a tensile strength above 1.5 MPa is required at a binder level that still permits clean burnout at 450°C.
Batch-to-batch variation in ash content is controlled by the certificate of analysis. A shift from 0.03% to 0.05% ash may be insignificant for coatings but can alter dielectric loss in ceramic capacitors. The powder should be stored sealed and pre-dried at 60°C for 4 h when exposed to humidity above 60% RH. Published data for Mowital B 20 H in tape-cast high-frequency capacitor configurations is limited; users should verify burnout residues on their own kiln profiles and atmosphere-control settings.
Heat-seal lacquers on aluminium foil and paper packaging require a sealing initiation temperature that is high enough to avoid blocking in roll storage but low enough to seal on high-speed form-fill-seal machines. Mowital B 20 H has higher cohesive strength and a higher heat-seal initiation than Mowital B 16 H; it also retains less plasticizer migration under storage at 35°C. When a converter switches from B 16 H to B 20 H at equal plasticiser content, the seal bar temperature must often be increased by 5–10°C to restore the same seal strength. This shift is measured on a laboratory heat-seal tester according to ASTM F88/F88M-21 at a dwell time of 0.5 s and pressure of 0.2 MPa. The same switch can reduce blocking in slit rolls when stored for 72 h under 40 kPa axial pressure, because film creep is lower.
Differences from other Mowital grades in this application are mainly rheological and mechanical. Mowital B 30 H gives higher seal strength and better hot-tack but requires lower application solids or a more aggressive solvent blend to maintain gravure cylinder release. Mowital B 16 H dissolves more quickly and allows higher coating speeds at low oven capacity, but yields a softer film that can build up on cutting knives. Mowital B 20 H occupies the intermediate position; a gravure cylinder with 70–90 lines/cm and a coating speed of 150 m/min is a typical starting point for a lacquer at 20% solids in ethanol/ethyl acetate 4:1. The exact values depend on foil gauge and sealing jaw geometry.
No single viscosity value defines suitability for all heat-seal formulations. Manufacturing condition differences—web tension, nip loading, and residual solvent—are as influential as the PVB grade. Published data for Mowital B 20 H in high-speed aluminium-lid heat-seal configurations is limited; the user should run a full matrix using the specific substrate and machine rather than extrapolate from chipboard or paper to foil. Incompatibility with wax-based release agents is observed above 0.5% residue, which can reduce adhesion and create seal failures at the score line.
| Grade | Relative solution viscosity | Typical consequence in heat-seal and ink formulation |
|---|---|---|
| Mowital B 16 H | Lower | Higher application solids possible; softer dried film; more rapid solvent release |
| Mowital B 20 H | Medium | Balanced spray viscosity, cohesion, and pigment wetting |
| Mowital B 30 H | Higher | Greater toughness and heat-seal strength; more solvent or lower solids required |
Residual solvent analysis in dried Mowital B 20 H coatings is performed by headspace gas chromatography using ISO 11890-2:2020 or equivalent. Ethanol retention above 0.5 mg/m² in printed film can plasticise the binder and increase blocking; acetaldehyde and butyraldehyde are monitored as decomposition markers. When Mowital B 20 H is compared with lower-viscosity PVB, the higher molecular weight fraction requires longer solvent diffusion time. Users should not set oven temperatures above 80°C for thin coatings on temperature-sensitive substrates, because surface skin formation traps residual solvent and can create blisters. The acceptable solvent retention limit is application-specific and should be derived from migration testing under EU 10/2011 when the coated material contacts food.
For powder handling, dust generation should be controlled to avoid combustible dust clouds. Equipment in zones where the powder is charged into dispersers should be assessed under ATEX Directive 2014/34/EU; grounding and inerting are standard controls. These requirements are operational rather than product-specific, but they apply to the fine particle size distribution of the dry resin.
