| HS Code | 327359 |
| Product Name | Kuraray Mowital G 13 |
| Chemical Type | Polyvinyl butyral (PVB) |
| Cas Number | 63148-65-2 |
| Appearance | White to pale yellow free-flowing powder/granule |
| Specific Gravity | 1.08 - 1.10 g/cm³ at 20 °C |
| Viscosity | 13 mPa·s (10 wt% solution in ethanol at 20 °C) |
| Molecular Weight | Approx. 25,000 g/mol (weight average) |
| Glass Transition Temperature | 62 - 66 °C |
| Softening Point | 65 - 70 °C |
| Refractive Index | 1.485 - 1.49 |
| Hydroxyl Content | 18 - 21 wt% |
| Butyral Content | 75 - 80 wt% |
| Acetyl Content | 0.5 - 1.5 wt% |
| Acid Number | ≤ 0.5 mg KOH/g |
| Tensile Strength | 45 - 55 MPa |
| Elongation At Break | 80 - 110% |
| Water Absorption | ≤ 1.0 wt% |
| Solubility | Soluble in alcohols, ketones, esters, glycol ethers, and chlorinated hydrocarbons; insoluble in water, aliphatic hydrocarbons, and mineral oils |
As an accredited Kuraray Mowital G 13 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Kuraray Mowital G 13 is supplied as free-flowing granules in 25 kg multi-layer paper bags with a polyethylene inner liner. |
| Container Loading (20′ FCL) | Kuraray Mowital G 13 loaded in 20′ FCL: 25 kg bags on shrink-wrapped pallets, securely stowed, protected from moisture and damage. |
| Shipping | Kuraray Mowital G 13 is a fine polyvinyl butyral resin powder, non-hazardous for transport under normal conditions. Ship in sealed, moisture-proof bags or containers, protected from heat, humidity, and ignition sources. No special UN classification required; standard dry cargo handling applies. Avoid dust accumulation and store in a cool, ventilated area. |
| Storage | Store Kuraray Mowital G 13 in a cool, dry, well-ventilated area, away from heat, open flames, and direct sunlight. Keep the original container tightly closed to prevent moisture absorption and contamination. Avoid humid conditions, as water can affect product performance. Follow recommended shelf life guidelines and rotate stock accordingly. |
| Shelf Life | Shelf life is typically 2 years when stored in the original container in cool, dry conditions away from heat and moisture. |
In solvent-based flexographic surface printing on corona-treated biaxially oriented polypropylene, Mowital G 13 is incorporated as a polar binder to raise adhesion and pigment wetting in polyurethane/nitrocellulose ink systems. A typical mill base is prepared with 15–20 parts Mowital G 13, 10–15 parts nitrocellulose, and 25–35 parts organic pigment dispersed in 100 parts of a 70:30 ethyl acetate/ethanol blend using a closed-bead mill at 50–55°C. The finished flexo ink is thinned to 20–24 s on a Zahn Cup #3 at 25°C per ASTM D4212. On a central impression flexo press running 300–500 m/min, PVB content above 12 wt% of finished ink increases high-shear viscosity and causes misting at chambered doctor blade stations. Adhesion to BOPP is tested by tape pull according to ASTM D3359 method B; corona-treated film at ≥38 dyn/cm typically holds 5B when the PVB:nitrocellulose ratio is kept between 1:1 and 1.5:1. Rosin-modified phenolic resins with acid numbers above 140 mg KOH/g should be limited below 5 wt% because they destabilize PVB solution clarity and reduce gloss. Indirect food packaging inks are qualified against FDA 21 CFR 175.105 for adhesive components and tested for overall migration under EN 1186-1, with published migration limits applied according to the specific food simulant. Terminal use includes printed snack food wrappers, confectionery pouches, and lidding stock where low retained solvent in the print film is required before lamination.
Mowital G 13 serves as the film-forming binder in two-pack wash primers and etch primers for galvanized steel, aluminium, and stainless steel. The base component contains 5–8 wt% PVB solids dissolved in a 1:1 isopropanol/toluene blend, 6–10 wt% zinc phosphate, 2–4 wt% talc, and 0.5–1.0 wt% carbon black; the acid component is 85% phosphoric acid diluted to 10–20% in isopropanol. Base and acid are mixed at 4:1 by volume and allowed an induction time of 30 min at 20°C before spray application. Pot life is limited to 8–12 h by PVB acetal hydrolysis in the acidic medium and by progressive zinc phosphate dissolution, which raises viscosity and reduces adhesion. Applied dry film thickness is 7–12 µm; thicker films cause undercutting at scribe lines because the cured wash primer is porous and requires an overcoat within 24 h. Salt spray performance per ISO 9227 on cold-rolled steel with a two-coat alkyd topcoat shows scribe creep below 2 mm after 240 h; adhesion is measured at class 0 by ISO 2409. Substrates must be degreased and lightly blasted to Sa 2.5 per ISO 8501-1. The terminal product is an anti-corrosion pretreatment for structural steel, railway wagon bodies, and aluminium architectural profiles.
During non-aqueous tape casting of alumina substrates and barium titanate multilayer ceramic capacitors, Mowital G 13 is dissolved at 10–15 wt% in an azeotropic 60:40 toluene/ethanol mixture, then mixed with plasticizer at 5–10 parts per 100 parts resin and ceramic powder at 60–65 vol% solids. Ball milling with 3 mm yttria-stabilized zirconia media for 16–24 h produces a shear-thinning slurry with typical viscosity of 1000–2500 mPa·s at 10 s⁻¹ on a cone-and-plate rheometer. The slurry is de-aired under 50–100 mbar vacuum for 10–15 min and cast onto silicone-coated polyester carrier film using a doctor blade with gap settings from 200–800 µm; casting speed is 0.2–0.8 m/min. After drying at 25–40°C for 24 h, green tape retains 1–2 wt% residual solvent, which must be held below 1.5 wt% to prevent lamination defects. Binder burnout follows a ramp of 0.5–2°C/min to 500°C; rates above 5°C/min generate internal pressure from PVB decomposition and cause edge cracking or delamination. The PVB/plasticizer ratio is adjusted so that green tapes show tensile strength of 3–6 MPa and elongation of 20–40% per ISO 527-3. Fired ceramic density and water absorption are checked by ASTM C373. Published data for Mowital G 13 in MLCC dielectric tape is limited; the binder window is therefore adjusted empirically against green tape lamination performance and sintered layer flatness. Terminal components include alumina substrates, LTCC modules, and MLCC dielectric layers.
For pharmaceutical blister lidding and single-portion sachet foil, Mowital G 13 is plasticized with 15–30 phr of a polymeric or monomeric plasticizer and coated from methyl ethyl ketone/toluene by reverse gravure. Dry coat weight is controlled at 2–5 g/m²; coating viscosity at the gravure station is 18–25 s on a Zahn Cup #3 at 25°C. The lacquer is dried in a three-zone oven with peak web temperature 120–140°C, and residual solvent is held below 50 mg/m² by gas chromatography for FDA 21 CFR 175.300 extractives testing. Heat-seal bonds are formed at 160–200°C, 0.3–1.0 s dwell, and 2–4 bar jaw pressure against PVC, PVdC, or polystyrene blister sheet. Peel strength measured on a 25 mm wide strip at 200 mm/min per ASTM F88 ranges from 4–8 N/15 mm; cohesive failure within the lacquer is acceptable, whereas lack of fibre tear on paper-backed foil indicates insufficient lacquer anchorage. Storage under 40°C/75% RH for 6 months must not reduce peel strength by more than 30%. The terminal products are pharmaceutical lidding foil, diagnostic strip foil, and food sachet stock.
Adhesion to untreated aluminium and glass-fibre-reinforced polyester in thermoformed automotive interior panels is achieved with a solvent-borne laminating adhesive containing Mowital G 13, epoxy resin, and an aminosilane coupling agent. The adhesive is applied at 8–12 g/m² dry film by air-knife coating; the PVB content is 30–45 wt% of total solids with epoxy resin at 20–30 wt% and silane at 1–2 wt%. Open time is controlled to 10–15 min before lamination at 90–110°C and 0.5–1.0 bar to avoid premature crosslinking. Amine-based hardeners must be avoided because they react with residual acetate and acetal groups in PVB, generating gel particles that clog spray equipment and reduce peel strength. T-peel strength per ASTM D1876 at 200 mm/min is maintained between 3 and 6 N/mm after 7-day room-temperature conditioning. The terminal product is a laminated interior trim panel with low fogging requirements verified by ISO 6452.
Mowital G 13 is used in thin coil coating primers for hot-dip galvanized steel where post-forming adhesion and weldability are required. The primer contains 10–15 wt% PVB, 30–40 wt% zinc dust, 10–15 wt% precipitated silica, and 3–5 wt% phenolic resole resin. On a reverse roller-coat line running 80–120 m/min, the film is cured to a peak metal temperature of 199–216°C for 20–40 s. Dry film thickness is held at 5–8 µm to maintain spot-weldability; above 10 µm, zinc dust at the surface can increase electrode wear. T-bend tests per EN 13523-7 on 0.5 mm galvanized substrate show no visible crack at 1T when PVB content is above 12 wt%. Solvent resistance measured by methyl ethyl ketone double rubs per ASTM D5402 exceeds 100 after full cure. Terminal products include appliance outer panels, garage door sections, and ceiling cassette substrates.
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Kuraray Mowital G 13 is a low-viscosity polyvinyl butyral resin supplied as a free-flowing granulate. The polymer backbone consists predominantly of vinyl butyral units, with a controlled residual vinyl alcohol fraction and a minor vinyl acetate fraction. The nominal solution viscosity of 13 mPa·s is determined for a 10 wt% solution in ethanol at 20 °C by the falling-ball method of DIN 53015. This places the grade below Mowital B 16 H and Mowital B 30 H in solution viscosity, allowing formulators to raise non-volatile content while maintaining press-ready viscosity. The dry resin shows a glass transition temperature of approximately 68 °C by differential scanning calorimetry according to ISO 11357-2. Volatile matter is normally below 3.0 wt% by ISO 3251, and sulfated ash is below 0.05 wt% by DIN EN 1245. The granulate form reduces dusting in production-scale dissolvers and gravimetric feeders, with bulk density in the range of 0.4–0.6 g/cm³ by ISO 60.
| Property | Test method | Typical value |
|---|---|---|
| Dynamic viscosity, 10 wt% ethanol solution, 20 °C | DIN 53015 | 13 mPa·s |
| Glass transition temperature, DSC second heating | ISO 11357-2 | 68 °C |
| Volatile matter | ISO 3251 | <3.0 wt% |
| Sulfated ash | DIN EN 1245 | <0.05 wt% |
| Bulk density, granulate | ISO 60 | 0.4–0.6 g/cm³ |
In a multi-station flexographic press with interstage hot-air dryers operating at 60–80 °C and line speed between 200 m/min and 300 m/min, solvent retention is a critical defect source. Mowital G 13, because of its 13 mPa·s solution viscosity, allows formulators to reduce the proportion of slow-evaporating glycol ethers such as dipropylene glycol monomethyl ether while maintaining capillarity on the anilox roller. The binder’s narrower molecular weight distribution reduces the high-molecular-weight tail that raises low-shear viscosity and delays film formation. Residual solvent in dried ink films can be quantified by headspace gas chromatography according to ISO 11890-2; typical target values for flexible packaging are below 10 mg/m² for total retained solvents. Block resistance after rewind can be evaluated by ISO 11502 or a constant-load blocking test at 60 °C for 24 h; formulations using Mowital G 13 generally show lower surface tack than higher-viscosity PVB grades because lower molecular weight increases diffusion-controlled solvent release. Adhesion to corona-treated polyethylene terephthalate film is assessed by tape peel per ASTM D3359-17; the hydroxyl functionality of the resin contributes to hydrogen bonding with surface carboxyl and carbonyl groups generated at treatment levels of 40–50 mN/m surface energy. Published data for specific ink formulations based on Mowital G 13 are limited, but the viscosity position is sufficiently established for use as a direct replacement for low-viscosity PVB or as a co-binder with cellulose nitrate in solvent-based packaging inks.
In two-component metal pretreatment primers, Mowital G 13 is dissolved in a blend of methyl ethyl ketone, ethanol, and toluene, and then let down with phosphoric acid at concentrations between 1.5 wt% and 3.0 wt% of total formulation. The PVB film provides a flexible barrier that passivates steel and aluminium surfaces before topcoating. Salt-spray resistance of the primed substrate is tested according to ISO 9227; typical scribe creep after 500 h on degreased cold-rolled steel is below 2 mm when the primer is applied at 5–8 µm dry film thickness. The low solution viscosity allows airless spray equipment with 0.28–0.33 mm spray tips to atomize the primer at lower pump pressure than higher-viscosity grades, reducing overspray and improving edge coverage. The resin is incompatible with amine-based curing agents because the acidic phosphoric acid system neutralizes basic hardeners and can gel the PVB; therefore, the primer is formulated as a single-pack etch primer and not as an amine-cured two-component system.
Heat-sealable coatings for aluminium foil and metallized film are formulated by dispersing Mowital G 13 in ethyl acetate and isopropanol at 20–30% non-volatile content, then applying by gravure or reverse roll coating to a dry coat weight of 1.5–3.0 g/m². When the same formulation is compared with a cellulose acetate propionate binder of similar solution viscosity, the PVB-based primer shows higher ultimate seal strength after a 0.5 s dwell at 180 °C jaw temperature when tested according to ASTM F88/F88M-21. The difference is attributed to thermoplastic flow of PVB and its adhesion to aluminium oxide surfaces; measured seal strengths on 20 µm aluminium foil frequently exceed 8 N/15 mm, whereas cellulose ester primers can remain below 5 N/15 mm under identical heat-seal conditions. Mowital G 13 also contains no resol-type phenolic resin; its extractables profile must be confirmed for the intended food-contact structure under 21 CFR 175.300 or 21 CFR 177.1200, depending on end use. The dry primer is resistant to ester- and alcohol-based solvents in subsequent lamination, but prolonged exposure to ketones above 40 °C can swell and delaminate the film; therefore, solvent-wipe operations with methyl ethyl ketone should be limited to short contact times below 30 s.
For ceramic tape casting of alumina or barium titanate substrates, Mowital G 13 is dissolved in a methyl ethyl ketone/ethanol azeotrope and mixed with ceramic powder, plasticizer, and dispersant. A typical slurry is milled in a ball mill with zirconia media until a Hegman fineness below 10 µm is reached; the slurry is then cast through a slot die onto a polyethylene terephthalate carrier at wet film thicknesses between 100 µm and 400 µm. The low ash content below 0.05 wt% by DIN EN 1245 is critical because alkali and alkaline-earth residues alter sintering densification and grain growth in barium titanate formulations fired above 1,200 °C. Thermogravimetric analysis in air at a heating rate of 10 °C/min shows complete organic burnout below 450 °C; residual carbon after debinding can be quantified by combustion analysis. Binder content is normally 8–12 wt% of ceramic solids, and the lower viscosity of Mowital G 13 allows the slurry to maintain a high solids loading of 55–65% by volume without exceeding the 1,500–2,500 mPa·s Brookfield viscosity window required for defect-free tape casting. If an exact burnout profile for a specific slurry is required, thermogravimetric analysis of the actual formulation is necessary because ceramic powders may catalyze or inhibit binder oxidation.
Compared with high-viscosity PVB grades used in laminated safety-glass interlayers, Mowital G 13 is not processed by plasticizer extrusion into interlayer film because its low molecular weight gives insufficient melt strength. It is instead used as a solution-processed binder where low solution viscosity, solubility in alcohol/ester blends, and low ash are more important than extrudate toughness. Unlike carboxylated acrylic binders, PVB offers higher tensile strength per unit of binder and better pigment wetting in solvent systems, but it requires a polar solvent blend because aromatic hydrocarbon tolerance is limited. The resin is supplied as granules to reduce dusting relative to powder grades; bulk density must be accounted for in gravimetric feeding equipment. Storage stability in sealed containers at 25 °C and below 60% relative humidity is at least 24 months; pre-drying is recommended if the granulate has been exposed to RH above 60% because absorbed water can cause haze in solvent-borne systems.
