| HS Code | 344036 |
| Product Name | S-LEC BL-1 |
| Chemical Type | Polyvinyl butyral (PVB) resin |
| Appearance | White powder |
| Specific Gravity | 1.08 - 1.10 |
| Refractive Index | 1.49 |
| Glass Transition Temperature | 70 °C (approx.) |
| Butyral Content | 69.5 mol% |
| Hydroxyl Content | 29 mol% |
| Acetyl Content | 1.5 mol% |
| Molecular Weight Mw | 50,000 - 60,000 |
| Viscosity 5 Ethanol Solution | 20 - 40 mPa·s |
As an accredited S-LEC BL-1 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | S-LEC BL-1 polyvinyl butyral resin is packaged in 20 kg polyethylene-lined paper bags, ensuring dry, contamination-free delivery. |
| Container Loading (20′ FCL) | S-LEC BL-1 is loaded as a 20′ FCL in sealed, labeled bags on pallets, ensuring safe, stable transport. |
| Shipping | S-LEC BL-1 (polyvinyl butyral resin) is shipped as a non-hazardous solid in sealed multi-layer paper bags or drums. Store away from moisture, heat, and open flames. Avoid dust generation. No special transport classification required under normal conditions; keep dry and ventilated during transit. |
| Storage | Store S-LEC BL-1 in a cool, dry, well-ventilated area away from direct sunlight, heat, and open flames. Keep the container tightly sealed to prevent moisture absorption and contamination. Avoid storing near oxidizing agents or incompatible materials. Maintain moderate temperature and low humidity to preserve resin quality and ensure safe handling. |
| Shelf Life | S-LEC BL-1 should be stored in a cool, dry place; shelf life is typically 12 months from manufacturing date. |
In flexographic and gravure surface-print applications for corona-treated BOPP and PET, S-LEC BL-1 functions as the primary film-forming resin where low solution viscosity and high pigment wetting are required at press speeds above 150 m/min. The resin is typically dissolved at 8–12 wt% solids in a 70:30 ethanol/ethyl acetate solvent blend by mass. Dissolution is conducted in a closed high-shear dissolver with a tip speed of 12–18 m/s and jacket temperature held at 35–40 °C. Temperatures above 45 °C should be avoided during prolonged dissolution because partial hydrolysis of butyral groups releases butyraldehyde, which reacts with alcohol solvents and shifts the apparent pH of the vehicle. A separate pigment base is milled with 15–20 wt% pigment, 3–5 wt% S-LEC BL-1 on total mill base, and 0.5–1.5 wt% dispersant calculated on pigment mass. Particle fineness after milling is checked on a grindometer per ISO 1524; the reading should be below 5 µm. The letdown ink is adjusted to 20–25 s DIN 53211 4 mm cup at 25 °C for rotogravure and 25–30 s for flexographic chamber doctored presses. Dried film adhesion is checked by ISO 2409 cross-cut on 20 µm corona-treated BOPP; the acceptance limit is no detachment exceeding 5% of the lattice area at 23 ± 2 °C and 50 ± 5% RH. Ambient relative humidity above 60% RH can produce solvent blush because the alcohol-rich vehicle absorbs moisture; gloss is then measured at 60° per ISO 2813 to detect surface haze. In high-speed flexo process inks, S-LEC BL-1 is frequently combined with nitrocellulose at a PVB-to-nitrocellulose ratio of 1:4 to 1:2 by mass; increasing the PVB fraction above 30% of total binder improves rub resistance but narrows alcohol tolerance. The finished product is a printed flexible packaging or label stock. For food-contact printed structures, the dried ink system must be confirmed against FDA 21 CFR 175.300 or EU Regulation 10/2011 migration limits for the intended food simulant.
Binder burnout, not slurry viscosity, is the limiting process constraint when low-molecular-weight PVB is used in BaTiO₃ green tape for nickel-electrode multilayer ceramic capacitor production. A reference suspension combines 100 parts by mass BaTiO₃ powder with a D50 of 0.4–0.6 µm and BET surface area of 3–5 m²/g, 6–12 parts S-LEC BL-1, 2–5 parts benzyl butyl phthalate, 0.5–1.5 parts menhaden fish oil dispersant, and a solvent system of 60:20:20 methyl ethyl ketone/ethanol/toluene by mass. Milling is performed in a zirconia bead mill at 1.5–2.5 m/s tip speed for 4–8 h, followed by deaeration under -90 kPa for 30 min. The slurry viscosity target is 2–5 Pa·s at 10 s-1 shear rate on a cone-plate rheometer; below 2 Pa·s the cast thickness control is lost, while above 5 Pa·s air removal is slow and pinholing persists. The slurry is cast through a doctor blade gap of 150–300 µm onto silicone-coated PET at 0.3–1.0 m/min. The first drying zone is set at 40–50 °C and the last at 70–80 °C; a faster solvent flash creates a surface skin that traps residual MEK and produces orange-peel defects visible under SEM at 2000×. Dried green tape tensile strength is evaluated using a universal testing machine with a 50 N load cell; the tape must survive punching without edge cracking below 3% elongation at break. Batch-to-batch ash content below 0.05 wt% should be verified by combustion at 600 °C because inorganic residues alter the Ni-BaTiO₃ co-firing atmosphere at the electrode-dielectric interface.
Thermal removal of the PVB binder is evaluated by TGA per ISO 11358-1 in air at 10 °C/min. The critical interval is 250–450 °C. If the heating rate exceeds 2 °C/min through this interval in a box furnace, the decomposition front outpaces oxygen diffusion and leaves carbonaceous residue; the resulting dielectric can show insulation resistance below 1 × 10¹¹ Ω and a shift in capacitance-temperature coefficient outside IEC 60384-22 X7R limits. In tunnel kiln operation, a pre-sintering burnout zone is held at 350–450 °C for 2–4 h with airflow of 0.5–1.0 m/s. Residual carbon after burnout is checked by combustion analysis and is required to remain below 0.1 wt%. Published peer-reviewed data for S-LEC BL-1 in this specific BaTiO₃ system are limited; the stated window is derived from PVB binders of comparable molecular weight and hydroxyl functionality under air-fired ceramic processing.
| Thermal interval | Observed event | Process control requirement |
|---|---|---|
| 25–150 °C | Residual solvent and low-mass plasticizer release | Ramp below 5 °C/min; forced air 0.5 m/s |
| 150–250 °C | Plasticizer decomposition and early PVB side-group loss | Avoid surface skin formation; maintain ventilation |
| 250–450 °C | Main-chain scission and exothermic butyral decomposition | Hold zone; ramp ≤ 2 °C/min |
| 450–600 °C | Oxidation of residual carbon | Retain in air until carbon <0.1 wt% |
For aluminium foil lidding stock that must withstand retort at 121 °C for 30 min, S-LEC BL-1 can be formulated as a solvent-based heat-seal lacquer. The lacquer is applied by direct gravure at a dry coating weight of 3–5 g/m² onto 20–25 µm soft-temper foil and dried at 80–120 °C for 10–20 s in a forced-air tunnel. Heat sealing to a 300–500 µm PVC tray is performed at 170–200 °C jaw temperature, 0.3–0.5 MPa pressure, and 1.0–1.5 s dwell. Seal strength is tested on 15 mm strips per ASTM F88/F88M-21; a minimum value of 6 N/15 mm is expected for retortable lidding. The required failure mode is cohesive within the tray polymer or foil tearing; adhesive failure at the foil-lacquer interface indicates insufficient foil anchorage, corrected by raising the wetting tension to 42–46 mN/m measured per ASTM D2578. A slip additive such as erucamide may be added at 0.5–1.0 wt% of dry coating to prevent blocking, but above 1.5 wt% it migrates to the seal interface and can reduce seal strength below the retort minimum. The final component is a peelable or lock-seal lidding membrane used in dairy, fruit, or ready-meal packaging. Food-contact status must be established under EU Regulation 10/2011, with overall migration below 10 mg/dm² in the finished package under the intended hot-fill or retort conditions.
Two-pack wash primers for structural steel and aluminium use S-LEC BL-1 as the film-forming vehicle because low molecular weight permits high solids at spray viscosity without excessive solvent demand. The base component consists of 7.5 wt% S-LEC BL-1, 7.0 wt% zinc tetroxychromate, 1.0 wt% carbon black, and 84.5 wt% 3:1 isopropanol/butanol by volume. The acid component is 10 wt% phosphoric acid in 90 wt% isopropanol with 5 wt% water. The components are mixed 4:1 by volume immediately before spraying. Pot life at 25 °C is 8 h; beyond that point viscosity rises because phosphate esters bridge PVB hydroxyl sites and chromate pigment adsorbs free acid. Application is by conventional air spray at 0.2–0.3 MPa fluid pressure and 10–15 µm wet film thickness, giving 3–5 µm dry film. The primed steel is topcoated within 24 h; unpainted wash primer is not a barrier coat and should not be evaluated as one. After topcoating, the system is exposed to salt spray per ASTM B117-19 for 1,000 h with scribe creep held below 2.0 mm. Amine additives are excluded because amines neutralize the phosphoric acid and can precipitate the PVB-chromate complex. Hexavalent chromium compounds require authorization under REACH Annex XIV; chromium-free zinc phosphate variants are used where a compliant alternative is specified.
Screen-printed front-side silver metallization for monocrystalline PERC solar cells employs S-LEC BL-1 in the organic vehicle at 0.5–2.0 wt% of total paste mass to control screen release and dried finger edge definition. The silver powder used in the paste is spherical with D50 1.0–2.0 µm and tap density 4.5–6.0 g/cm³; the vehicle is a mixture of terpineol and butyl carbitol acetate containing a small amount of ethyl cellulose and S-LEC BL-1 as a temporary binder. Printing is performed through a 360–430 mesh stainless steel screen with 15–20 µm emulsion thickness. Wet finger width after printing is 35–45 µm, and edge bleed must remain below 5 µm to avoid busbar spacing loss. The wet layer is dried at 150–250 °C for 30–60 s in an IR belt dryer, leaving S-LEC BL-1 as a temporary binder before firing. In the fast-firing furnace, peak temperature is 750–900 °C for 2–5 s. Incomplete binder burnout leaves carbon at the SiNₓ interface and raises contact resistivity; the transfer length method value should remain below 2 mΩ·cm². Published data for S-LEC BL-1 in PERC silver pastes is limited; cell manufacturers evaluate binder burnout by thermogravimetric analysis of the dried paste under firing profiles matched to the actual belt furnace. The finished cell is characterized by current-voltage testing under IEC 60904-1 and electroluminescence imaging for finger continuity.
Competitive S-LEC BL-1 prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615380400285 or mail to sales2@liwei-chem.com.
We will respond to you as soon as possible.
Tel: +8615380400285
Email: sales2@liwei-chem.com
Flexible payment, competitive price, premium service - Inquire now!
The resin designated S-LEC BL-1 is a low-viscosity polyvinyl butyral (PVB) grade supplied by Sekisui Chemical Co., Ltd. under the S-LEC B series. It is produced by acid-catalyzed acetalization of polyvinyl alcohol with n-butyraldehyde, yielding a terpolymer of vinyl butyral, vinyl alcohol, and residual vinyl acetate repeat units. Manufacturer technical data for BL-1 report a degree of polymerization of approximately 300 and a 10 mass% solution viscosity in ethanol/toluene (1:1 v/v) at 20 °C of 10–20 mPa·s. The glass transition temperature is typically near 66 °C, and the as-supplied resin is a free-flowing white powder containing no added plasticizer or inorganic filler. The specified ash residue after ignition at 600 °C is normally ≤ 0.05 mass%, a value that matters in fired-ceramic binder systems and in transparent coatings where mineral residues reduce clarity. Compared with higher-viscosity S-LEC PVB grades, BL-1 trades melt strength and film toughness for lower solution viscosity, higher solids-loading capacity, and faster solvent release. These characteristics position it in printing inks, wash primers, adhesive primers, and ceramic green-sheet binders rather than in laminated safety-glass interlayer film, which typically requires higher-molecular-weight PVB or crosslinked interlayer resins.
| Property | Representative value | Test basis |
|---|---|---|
| Polymer type | Polyvinyl butyral, CAS 63148-65-2 | — |
| Degree of polymerization | ~300 | GPC relative to PVB standard |
| Solution viscosity, 10 mass% in ethanol/toluene (1:1) at 20 °C | 10–20 mPa·s | Rotational viscometer, ISO 2555 |
| Vinyl butyral content | 63–67 mol% | Acetalization titration |
| Vinyl alcohol content | 31 mol% nominal | Hydroxyl titration |
| Residual vinyl acetate content | ≤ 3 mol% | Saponification titration |
| Glass transition temperature | 66 °C | DSC |
| Ash content | ≤ 0.05 mass% | ISO 3451-1, method A |
| Volatile content | ≤ 1.0 mass% | Loss on drying |
| Bulk density | 0.25–0.35 g/cm³ | Packed powder |
In tape-casting operations for alumina, zirconia, or barium titanate substrates, S-LEC BL-1 is typically combined with a solvent blend of ethanol and toluene or methyl ethyl ketone and ethanol, a plasticizer such as dibutyl phthalate or dioctyl phthalate, and a dispersant. A production-scale slurry mixer with high-shear dispersion is charged with ceramic powder to a final solids loading of 68–75 mass%, while the BL-1 binder is commonly added at 5–12 parts by mass per hundred parts of ceramic powder. The low degree of polymerization of BL-1 permits slip viscosities of 1,000–8,000 mPa·s at a shear rate of 10 s⁻¹ at high solids; these values are measured on a Brookfield RVT-type rotational viscometer with spindle 5 at 20 rpm after a controlled deaeration step under 20–30 kPa vacuum. Doctor-blade tape casting is run with a gap of 100–400 µm depending on final dried thickness, and the low-molecular-weight binder reduces shear-induced dilatancy in narrow-gap regions. Drying of the cast tape is carried out in multi-zone air-float dryers with first-zone temperature near 25–40 °C and final-zone temperature not exceeding 70–80 °C to prevent skin-over and residual solvent entrapment. The binder burnout profile for BL-1 is intentionally narrow: in a production air atmosphere with oxygen ≥ 8 vol%, the main degradation mass loss occurs between 250 °C and 400 °C, followed by a hold of 0.5–2 h at peak temperature to reduce residual carbon below 0.1 mass%. The low ash specification of the resin supports that carbon burnout conversion, but sintered parts can still show edge cracking if the binder content is dropped below the point where green tape tensile strength falls below 1 MPa. Published data for this specific configuration is limited; processors empirically adjust binder-to-plasticizer ratio and tape drying profile because BL-1 alone may produce lower green strength than higher-viscosity S-LEC grades such as BM-2 or BH-3.
In two-pack wash primers for steel and aluminium, S-LEC BL-1 is selected because its hydroxyl functionality provides controlled acid-catalyzed bonding to metal oxides without the high solution viscosity that would restrict spray application. A typical production primer contains 5–10 mass% BL-1, 0.5–2 mass% phosphoric acid (85% aqueous), and a corrosion-inhibiting pigment such as zinc phosphate; the solvent blend is often n-butanol, isopropanol, and toluene or xylene in ratios adjusted to maintain a dry-film thickness of 5–8 µm. The acid component etches the substrate and reacts with the hydroxyl groups in the PVB at ambient temperature, but the same reaction limits pot life. Viscosity rise and gelation have been observed within 8–24 h in closed containers when the acid level exceeds the recommended upper limit or when the primer is stored above 30 °C. Spray application through air-assisted airless equipment with nozzle orifice 0.28–0.38 mm is preferred because lower-molecular-weight BL-1 allows lower atomization pressure and reduces cobwebbing versus higher-molecular-weight PVB. Adhesion of the cured wash primer to degreased cold-rolled steel is evaluated by cross-cut tape pull according to ISO 2409:2013 or ASTM D3359-17; a rating of 0–1 is generally required for subsequent epoxy or alkyd topcoats. Where chromate-free requirements apply under REACH Annex XVII, zinc phosphate or organosilane inhibitors are substituted for zinc chromate, but the substitution reduces early wet adhesion; BL-1 is often blended with a low-level phenolic hardener to partially recover it. Processors should avoid amine-based neutralizing additives in this system because they deactivate the phosphoric acid and can precipitate PVB from solution.
BL-1 dissolves readily in lower alcohols, esters, ketones, glycol ethers, and chlorinated solvents; solubility in water and aliphatic hydrocarbons is limited. The standard dissolution procedure for printing-ink vehicles uses a high-speed disperser at a jacket temperature below 40 °C, adding powder slowly to an ethanol/toluene or ethanol/MEK blend under agitation. Because BL-1 has a low molecular weight, solution viscosity is more sensitive to resin solids than to temperature; raising solids from 10 mass% to 25 mass% can increase Brookfield viscosity by more than an order of magnitude, while heating from 20 °C to 40 °C reduces viscosity by only 15–30%. Formulators use this steep solids–viscosity response to maintain print viscosity while limiting total solvent demand. In gravure and flexographic ink applications, the resin is typically accompanied by nitrocellulose or polyamide modifiers and a plasticizer such as dibutyl sebacate at 10–30 parts per hundred resin; the resulting vehicle has viscosity in the range 20–150 mPa·s at 25 °C. Alcohol-rich diluents are preferred where high toluene retention is restricted; however, increasing alcohol content above 70 mass% can produce hazy solutions at low temperature, because the higher hydroxyl fraction of BL-1 is less compatible with aliphatic hydrocarbons than lower-hydroxyl PVB grades. The solution should be filtered through 10–20 µm bag filters after dissolution to remove gel particles and undispersed powder.
Where BL-1 is used as a ceramic binder and dispersant, the same solubility behavior controls slurry stability. Solvent blends of MEK/ethanol at 60:40 to 80:20 by mass are typical. Slurry viscosity should be checked after 24 h aging because PVB solutions can undergo slight hydrolysis in acid-doped ceramic slurries; pH is normally maintained above 4.5 to minimize that drift.
Storage and handling constraints follow from the polar structure of PVB and the low glass transition of the resin. Bags should be kept sealed at ≤ 30 °C and relative humidity ≤ 60%; prolonged exposure to moisture can promote powder agglomeration and increase volatile content to above 0.5 mass%. Once opened, the resin should be consumed in full-batch quantities or resealed under dry nitrogen. Dust from the powder is combustible as an organic dust; local exhaust ventilation and grounding are required in production areas where powder is transferred. The material is not a food-contact article as supplied, and any food-contact status must be established through the finished article under the applicable regulations, such as 21 CFR 175.105 for adhesive components or EU 10/2011 for plastics in contact with food. Compatibility with plasticized vinyl films is generally good, but direct contact with certain polycarbonate or acrylic grades under stress can cause environmental stress crazing; solvent screening on the final substrate is therefore required.
