| HS Code | 976733 |
| Chemicalname | Polyvinyl butyral (PVB) |
| Casnumber | 63148-65-2 |
| Appearance | White free-flowing powder or granules |
| Molecularweight | Approx. 40,000 g/mol |
| Viscosity | Approx. 30 mPa·s (10% in ethanol, 20°C) |
| Hydroxylcontent | Approx. 18 wt% |
| Acetalcontent | Approx. 80 wt% |
| Acetatecontent | Approx. 1 wt% |
| Glasstransitiontemperature | Approx. 65 °C |
| Density | Approx. 1.1 g/cm³ |
| Softeningpoint | Approx. 190 °C |
| Solubility | Soluble in ethanol, methanol, glycol ethers, ketones, and esters |
As an accredited Mowital B 30 T factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Mowital B 30 T is supplied as a free-flowing powder in 25 kg multi-layer paper bags, palletized for safe handling and storage. |
| Container Loading (20′ FCL) | Mowital B 30 T (PVB resin) loaded in 20′ FCL, packed in sealed bags on pallets, shrink-wrapped and securely stowed. |
| Shipping | Mowital B 30 T is a polyvinyl butyral resin supplied as a free-flowing powder. It is non-hazardous for transport, shipped in sealed multi-layer paper bags or drums. Store in a cool, dry area away from moisture, heat, and ignition sources. Protect packaging from damage and keep upright during handling. |
| Storage | Store Mowital B 30 T in its original, tightly sealed container in a cool, dry, well-ventilated area. Protect from moisture, direct sunlight, and heat sources. Keep away from open flames and strong oxidizers. Ideal storage temperature is 15–25°C. Avoid stacking heavy items on bags to prevent caking or damage. |
| Shelf Life | Shelf life is 2 years when stored in original unopened packaging, in a cool, dry place away from moisture. |
In barium titanate multilayer ceramic capacitor tape casting, Mowital B 30 T is introduced at 3.0–7.5 parts per hundred parts ceramic powder by weight. The resin solution is prepared in an 80:20 w/w methyl ethyl ketone/ethanol blend and milled in a high-energy bead mill charged with 0.3–0.5 mm zirconia media at 8–10 m/s tip speed until a Hegman fineness of 5–6 µm is reached. A dibutyl phthalate plasticizer addition of 1–2 parts per hundred parts ceramic powder is made after the mill base is cooled below 35 °C. The resulting suspension is tape-cast with a 200 µm doctor blade gap onto a polyethylene terephthalate carrier moving at 0.8–1.2 m/min, then dried through three forced-air zones set at 50 °C, 60 °C, and 70 °C. Dried green tape thickness of 55–70 µm supports via punching, blanking, and stacking without edge chipping. Green tensile strength tested under ISO 527-3 is 3–6 MPa at 25 °C and 50 % RH. Binder burnout is performed at a ramp rate of 0.5 °C/min to 450 °C with a 2 h dwell under flowing air at 3–5 air changes per minute; the main decomposition interval is 200–400 °C. Residual carbon above 0.1 wt% after burnout is rejected because it raises dielectric loss in sintered layers. Ceramic powder moisture above 0.3 wt% requires pre-drying at 120 °C for 4 h before dissolution, and casting under relative humidity above 60 % typically produces surface tack and slitting defects.
When Component A and Component B are combined, the mixed primer must be sprayed within 4–6 h at 23 °C. Component A is produced by dissolving 8–10 wt% Mowital B 30 T in a 2:1:1 w/w methyl isobutyl ketone/n-butanol/xylene blend; Component B is 85 % aqueous phosphoric acid diluted 1:4 with isopropanol. Mixing at 4:1 by volume gives an acid concentration of 0.4–0.6 wt% in the final primer. At this concentration the residual hydroxyl groups of the PVB contribute to adhesion on zinc-galvanized steel and zinc phosphate conversion layers. The acid also catalyses partial acetal ring hydrolysis, which increases solution viscosity from approximately 25–35 mPa·s to above 80 mPa·s by the end of pot life. Spray application through a 1.0–1.2 mm nozzle at 2.5–3.0 bar produces a dry film of 5–7 µm. Cross-cut adhesion to cold-rolled or galvanized steel per ISO 2409:2013 is class 0 after 24 h at 23 °C and 50 % RH. Salt spray resistance to ISO 9227:2017 NSS for 500 h is specified when the primer is overcoated with two-component epoxy; production failures are usually filiform corrosion when dry film thickness exceeds 10 µm or when substrate temperature falls below 10 °C. Historically zinc tetroxychromate was used as an anticorrosion pigment in this primer class; current REACH restrictions drive chrome-free alternatives. Adding 0.5–1.0 wt% tetraethyl orthosilicate improves wet adhesion but reduces pot life to 2–3 h.
On high-speed central impression presses running at 250–450 m/min, Mowital B 30 T is post-added as a letdown resin at 4–6 wt% solids in solvent-based flexographic lamination inks for corona-treated biaxially oriented polypropylene and polyester. The resin is first dissolved at 25 % solids in ethyl acetate at 35–40 °C; the solution is then added to the finished pigment dispersion after the high-shear mixing step. Pigment wetting improves because the polyvinyl butyral segments adsorb on organic pigment surfaces while the residual polyvinyl alcohol groups maintain solubility in alcohol/ester solvent blends. Ink viscosity is monitored with a DIN 53211 4 mm flow cup at 20 °C; a working range of 18–22 s is maintained by solvent replenishment, not by additional resin, to avoid altering the pigment-to-binder ratio. Mist generation at the nip is reduced by the higher extensional viscosity of the PVB solution. Lamination bond strength to metallised polyester and low-density polyethylene is evaluated after 24 h per ISO 11339:2010; failure mode observed in production trials is ink pick-off when press-side viscosity exceeds 24 s and residual ethyl acetate remains above 5 mg/m² after drying. Mowital B 30 T is not suitable for water-based flexographic inks because the resin is incompatible with high-pH aqueous ammonia systems.
| Application segment | Compliance or test standard | Control parameter | Typical specification |
|---|---|---|---|
| Ceramic green tape binder | ISO 527-3 | Green tensile strength | 3–6 MPa at 25 °C, 50 % RH |
| Etch primer for galvanized steel | ISO 2409:2013 | Cross-cut adhesion | Class 0 after 24 h |
| Flexographic lamination ink | DIN 53211 | Flow cup viscosity, 4 mm | 18–22 s at 20 °C |
| Thick-film silver paste | ISO 1524:2013 | Fineness of grind | Below 10 µm |
| Phenolic resole structural adhesive | ISO 4587:2003 | Single-lap shear strength | Acceptance determined per adherend and surface preparation |
| Decorative transfer foil on MDF | ISO 2409:2013 | Cross-cut adhesion | Class 1 or better |
A 40 % solids structural adhesive lacquer is prepared by dissolving 70 parts phenolic resole and 30 parts Mowital B 30 T in methyl ethyl ketone. The lacquer is coated onto aluminum foil or polyester release film at 150–200 µm dry film thickness and used for aluminium honeycomb core bonding in aircraft interior panels. Curing is carried out at 150 °C under 0.5 MPa for 30 min; the PVB hydroxyl groups react with methylol groups on the resole, shifting the differential scanning calorimetry exotherm from 130–170 °C. Single-lap shear strength is evaluated per ISO 4587:2003; published data for this specific resin combination is limited, so development batches require full shear and wedge test programs on the actual adherend. When the B 30 T content exceeds 35 parts, the cured film shows excessive thermoplastic flow at 80 °C; below 25 parts, the dried adhesive film cracks during trimming and handling. Food-contact status for packaging adhesives must be verified against FDA 21 CFR 175.105 for the complete formulation, including residual solvent and co-curing agents.
Replacement of ethyl cellulose with Mowital B 30 T in silver conductor pastes for screen-printing onto alumina or low-temperature co-fired ceramic changes the organic burnout profile. The paste consists of 82–88 wt% silver powder, 2–5 wt% glass frit, 2–5 wt% Mowital B 30 T, and 5–10 wt% solvent containing terpineol and diethylene glycol monobutyl ether. The mixture is dispersed on a triple-roll mill with a gap of 5–15 µm in three passes until fineness of grind is below 10 µm per ISO 1524:2013. Screen printing is performed with a 325-mesh stainless steel screen and a shore 75 A squeegee. The printed conductors are dried at 120 °C for 10 min, then fired at 10 °C/min to 350 °C with a 30 min dwell, followed by a second ramp at 10 °C/min to 850 °C with a 10 min peak. The PVB decomposition onset near 200 °C and low ash content below 0.05 % support clean burnout in air-fired pastes; residual carbon defects are observed if the dwell at 350 °C is shortened below 20 min or if the paste is fired in a nitrogen atmosphere.
For decorative transfer foils applied to medium-density fibreboard, a 10 % solution of Mowital B 30 T in a 1:1 w/w n-propanol/ethyl acetate blend is applied by gravure cylinder at 2–4 g/m² dry coat weight. The coated foil is dried at 70–80 °C and hot-press laminated to profiled MDF at 120–140 °C under 0.3–0.5 MPa for 10–15 s. The terminal product is furniture edge banding and profile-wrapped mouldings. Cross-cut adhesion to the MDF surface per ISO 2409:2013 is class 1 or better when the MDF surface temperature is above 15 °C; lower substrate temperatures cause incomplete wetting and intercoat adhesion loss. The dry coat weight must be kept below 5 g/m² because higher primer loads create thermoplastic slip at the hot-press nip and cause foil edge lift after cooling.
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Mowital B 30 T is a thermoplastic polyvinyl butyral resin produced by acetalization of polyvinyl alcohol with n-butyraldehyde. The product is supplied as a white powder or granular solid and carries CAS number 63148-65-2. Chemically, it contains residual polyvinyl alcohol at 18–21 wt% and residual polyvinyl acetate at 1–3 wt%, with the balance as polyvinyl butyral. The grade is specified by the viscosity of a 10 wt% solution in ethanol measured at 20°C according to DIN 53015; the control window is 27–33 mPa·s. The glass transition temperature determined by ISO 11357-2 is approximately 68°C. Acid number is controlled at ≤1.0 mg KOH/g and density at 1.08–1.10 g/cm³ by ISO 1183-1.
Across production-scale printing and coating operations, the material functions as a film-forming binder in flexographic and gravure inks, wash primers, and heat-seal lacquers. The intermediate hydroxyl content provides adhesion to corona-treated polyolefins and metal substrates while still permitting dissolution in low-boiling alcohol/ester solvent blends. The residual hydroxyl groups are available for subsequent reaction with isocyanates, phenolic resins, and melamine-formaldehyde resins when chemical resistance is specified.
| Property | Unit | Typical specification | Test method |
|---|---|---|---|
| Appearance | — | White powder or granular solid | Visual |
| Solution viscosity, 10% in ethanol at 20°C | mPa·s | 27–33 | DIN 53015 |
| Polyvinyl alcohol content | wt% | 18–21 | Manufacturer saponification method |
| Polyvinyl acetate content | wt% | 1–3 | Manufacturer saponification method |
| Acid number | mg KOH/g | ≤1.0 | ISO 2114 |
| Glass transition temperature | °C | approx. 68 | ISO 11357-2 |
| Density at 23°C | g/cm³ | 1.08–1.10 | ISO 1183-1 |
| Moisture content | wt% | ≤2.0 | ISO 3251 |
| Ash content | wt% | ≤0.1 | ISO 3451-1 |
Temperature control at 20°C ± 0.1°C is critical because the viscosity of the ethanolic solution is strongly temperature dependent. Solvent water content is also controlled; moisture ingress into the solvent or resin can raise solution viscosity and blur the grade boundary between B 30 T and adjacent grades. Batch-to-batch variation in residual hydroxyl content within the 18–21 wt% window can shift solubility boundaries in alcohol-rich blends; incoming quality control therefore includes a viscosity check after drying the powder to below 2 wt% moisture. Acid number and ash content are used as indirect controls of residual catalyst and inorganic contamination. Elevated ash above 0.1 wt% can lower clarity in clear overprint varnishes and create haze in unpigmented coatings.
In flexographic ink manufacture, the resin is dissolved in a 90:10 w/w ethanol:ethyl acetate blend at 18–22 wt% solids in a jacketed high-shear disperser with a Cowles blade tip speed of 18–25 m/s. The premix is ground in a horizontal bead mill charged with 0.6–1.0 mm yttria-stabilized zirconia media until the dispersion reaches a Hegman gauge reading of 6–7. At the press, ink viscosity is adjusted to 25–35 s in a 4 mm DIN flow cup at 23°C. This viscosity band supports ink transfer from anilox cells to corona-treated low-density polyethylene at line speeds up to 250 m/min; above 300 m/min, reformulation with a faster solvent or a lower-viscosity grade such as B 20 H is generally required to avoid tailing and splashing. Residual moisture in the resin above 2 wt% is a known production bottleneck: it slows solvent release from the printed film and can increase retained-solvent readings in headspace gas chromatographic analysis.
In publication gravure inks, B 30 T is used at solids of 10–15 wt% in solvent blends based on ethyl acetate, ethanol, and methyl ethyl ketone. The inks are filtered through 5–10 µm bag filters before filling to prevent cylinder cell plugging. Press viscosity is adjusted to 15–20 s in a 3 mm DIN flow cup at 23°C. On supercalendered paper, the binder improves water resistance and reduces ink set-off when stacked at temperatures between 25°C and 40°C. Residual solvent limits for food-contact printing are assessed according to ISO 11890-2 or equivalent national standards when required.
Wash primer formulations typically combine the grade with a thermosetting phenolic resin and phosphoric acid at total solids of 7–10 wt% in methyl ethyl ketone/ethanol blends. The acid is added after the PVB is fully dissolved because localized phosphoric acid concentrations above 1 mol/L can catalyze acetal hydrolysis and cause a measurable drop in solution viscosity within 24 h. Adhesion to degreased cold-rolled steel is assessed by cross-cut according to ISO 2409 after 24 h at 23°C and 50% RH; typical systems remain within classification 0–1. For exterior specifications, primers are formulated with corrosion-inhibiting pigments and evaluated under neutral salt spray according to ISO 9227 when the end-use standard requires exposure data.
Within the Mowital B series, the grade is separated from B 14 S and B 16 H by its higher 10% solution viscosity of 27–33 mPa·s under DIN 53015. B 14 S and B 16 H are specified below 15 mPa·s, which gives them faster solvent release but lower mechanical strength and pigment wetting at equal binder content. Relative to B 45 M and B 60 T, B 30 T permits higher solids before application viscosity is exceeded, but it produces films with lower tensile modulus and reduced heat-seal strength. The residual polyvinyl alcohol content of 18–21 wt% places the product in an intermediate adhesion band: higher-hydroxyl Mowital variants show stronger covalent crosslinking with isocyanates and phenolic resins, while lower-hydroxyl grades exhibit lower hygroscopicity and better alcohol tolerance. The choice between B 30 T and B 30 HH is made by solubility screens in the target solvent blend and by measuring viscosity stability over 48 h at 23°C; published data for direct substitution in every solvent system is limited.
Relative to nitrocellulose-based ink binders, B 30 T does not require the same plasticizer loading to achieve flexible films. Nitrocellulose formulations often contain 20–30 wt% plasticizer on binder, whereas PVB films are typically plasticized at 5–10 wt% on binder. Compared with cellulose acetate butyrate, B 30 T has higher adhesion to metal and better compatibility with alcohol-rich solvent blends, but slower solvent release from gravure cells. Comparative laboratory evaluations are performed by casting films from 10 wt% solids solutions and measuring drying curves and solvent retention by headspace gas chromatography.
Because the polyvinyl acetal linkage is acid-sensitive, processing with strongly acidic additives must be controlled. In two-component primers, the PVB component should not be pre-mixed with amine-neutralizing additives that raise pH above 8 for extended periods, because alkaline conditions accelerate ester side-group hydrolysis and can increase the acid number above 1.0 mg KOH/g. Storage in original sealed containers at temperatures below 30°C and relative humidity below 60% is recommended. At 70% RH, polyvinyl butyral powder can absorb sufficient water within 72 h to exceed 2 wt% moisture; the resulting powder shows reduced solubility and may require pre-drying in a vacuum oven at 40°C for 4–6 h before use. In solvent-based inks, water contamination above 0.5 wt% in the solvent blend is known to raise final ink viscosity and cause pinholing in overprint varnishes.
Crosslinked coating systems based on B 30 T use the residual hydroxyl functionality. An aliphatic polyisocyanate is added at an NCO:OH ratio of 1.05:1–1.2:1 when chemical resistance is specified; films are cured at 23°C for 7 days before solvent-rub testing according to ASTM D5402. At NCO:OH ratios below 1.0:1, residual unreacted hydroxyl sites increase water sensitivity; above 1.3:1, excess isocyanate can create surface tack and yellowing. Phenolic resin crosslinking requires acid catalysis at 0.5–1.0 wt% of total binder solids and curing at 120–150°C for 15–30 min; this route is typical for metal coatings and heat-seal primers. The processing window is narrow because film cure at temperatures below 120°C leaves unreacted phenolic oligomers that plasticize the film, whereas temperatures above 160°C induce oxidation and yellowing in unpigmented clearcoats.
Heat-seal lacquers for aluminum foil are prepared by dissolving B 30 T at 8–12 wt% solids in ethyl acetate/ethanol mixtures with a plasticizer content of 5–10 phr. Sealing is performed at jaw temperatures of 120–140°C and contact pressures of 0.4–0.6 MPa for 1–2 s. Sealed specimens are evaluated according to ASTM F88/F88M-15; peel strength values are reported only when substrate thickness and jaw geometry are fixed, because published data for this specific resin-foil configuration is otherwise limited. Higher-viscosity Mowital grades increase seal strength but require lower coating weight to avoid blocking; lower-viscosity grades reduce seal strength and are used for easy-open applications.
