| HS Code | 653103 |
| Product Name | S-LEC BM-SZ |
| Chemical Family | Polyvinyl butyral (PVB) resin |
| Appearance | White powder |
| Form | Fine powder |
| Specific Gravity | 1.07–1.12 at 20°C |
| Refractive Index | 1.485–1.490 |
| Glass Transition Temperature | Approx. 72°C |
| Softening Point | Approx. 120°C |
| Hydroxyl Content | 18–23 wt% |
| Butyral Content | 65–70 mol% |
| Acetyl Content | 1–4 mol% |
| Average Molecular Weight | Approx. 30,000–50,000 |
| Viscosity | 10–20 mPa·s in 5% ethanol solution at 25°C |
| Acid Value | ≤0.5 mg KOH/g |
| Volatile Content | ≤2.5% |
| Solubility | Soluble in alcohols, esters, ketones, and glycol ethers; insoluble in water |
As an accredited S-LEC BM-SZ factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | S-LEC BM-SZ is supplied in sealed multi-layer paper bags, net weight 25 kg per bag, ensuring protection from moisture and contamination. |
| Container Loading (20′ FCL) | S-LEC BM-SZ shipped as 20′ FCL on pallets, secured, moisture-protected, and stably loaded for safe transport. |
| Shipping | S-LEC BM-SZ is shipped as a dry, granular PVB resin in sealed moisture-proof bags or drums. Store in a cool, dry area away from heat, moisture, and ignition sources. Non-hazardous for transport under normal conditions; protect from mechanical damage and direct sunlight during handling. |
| Storage | Store S-LEC BM-SZ in a cool, dry, well-ventilated area away from direct sunlight, heat, and ignition sources. Keep the container tightly closed to prevent moisture absorption and contamination. Avoid extreme temperatures and humidity. Ensure compatibility with storage materials and handle in accordance with safety data sheet recommendations. |
| Shelf Life | Store S-LEC BM-SZ in a cool, dry place away from moisture; shelf life is typically 24 months from manufacture date. |
In solvent-borne flexographic and gravure printing on corona-treated biaxially oriented polypropylene, cast polypropylene, and metallized polyester, S-LEC BM-SZ functions as a pigment-wetting and adhesion-promoting binder that maintains transfer on low-energy film at press speeds up to 250–350 m/min. The resin is dissolved at 40–50°C in a solvent blend of ethanol and ethyl acetate at 70:30–80:20, with n-propyl acetate added at 5–10 wt% of total solvent to slow surface film formation and reduce blocking on rewind. Finished flexographic inks typically contain 8–12 wt% resin, 15–22 wt% pigment, 1–2 wt% polyethylene wax, 0.5–1.5 wt% silane adhesion promoter, and ester/alcohol solvents to balance; gravure inks are adjusted to 25–35 s and flexo inks to 18–25 s on a DIN 4 cup at 25°C. Dispersion is carried out in a closed horizontal bead mill charged with 0.8–1.0 mm yttria-stabilized zirconia beads, with a residence time of 30–60 min and a final grind of 5 µm or finer on the Hegman scale. The drying tunnel is profiled across four zones at 40°C, 55°C, 65°C, and 55°C; tunnel temperatures above 70°C cause case-hardening because the PVB skin traps the slower n-propyl acetate tail, producing retained solvent and odor after lamination. At ambient relative humidity above 60%, the powder should be pre-dried at 45–50°C to below 0.5 wt% moisture before dissolving, because free water creates turbidity and reduces adhesion to metallized film. Adhesion is assessed on production film by ASTM D3359 method B tape pull, with a target classification of 4B or 5B on corona-treated polypropylene at 38–42 mN/m surface energy. After solventless adhesive lamination, bond strength is evaluated by ASTM D903; converter specifications commonly require 2.0–3.0 N/15 mm peel on metallized polyester. The printed web is over-laminated with polyethylene or cast polypropylene and converted into pouches, sachets, and lidding films for snack, confectionery, and frozen-food packaging.
In two-component wash primers for blast-cleaned steel and galvanized substrates, S-LEC BM-SZ is used as the film-forming resin that tolerates phosphoric acid-catalyzed adhesion chemistry without forming a brittle condensed film. The base component is formulated with 7–10 wt% BM-SZ, 8–12 wt% zinc phosphate or zinc tetroxychromate where permitted, 0.3–0.8 wt% iron oxide pigment, 60–70 wt% isopropanol and n-butanol, and 5–10 wt% xylene or toluene. The acid component is 85% phosphoric acid diluted in isopropanol, added at 0.4–1.0 wt% of total liquid. Pot life is limited to 4–6 h at 25°C because the acid gradually reacts with the hydroxyl groups; subsequent addition of amine-based anti-corrosion additives must be avoided because they neutralize phosphoric acid and delay film cure. Spray application with a conventional pressure pot at 0.3–0.5 MPa produces a dry film thickness of 5–10 µm. The primer is overcoated after 15–30 min at 25°C but before 24 h; overcoating after 72 h may require light scuff sanding because acid migration creates a polar surface layer. Adhesion after cure is assessed by ISO 2409 or ASTM D3359, with a required classification of 0–1 for blast-cleaned steel prepared to Sa 2.5 per ISO 8501-1. Salt spray resistance per ISO 9227 is evaluated only after topcoat application; scribe creep should remain below 2 mm after 500 h in a three-coat polyurethane system. The primer is used under epoxy, polyurethane, and alkyd topcoats on structural steel, storage tanks, and shipbuilding components.
| Standard | Test condition | Required result |
|---|---|---|
| ISO 8501-1 | Blast-cleaned steel before spray | Sa 2.5 |
| ISO 2409 | Cross-cut after 24 h cure | Class 0–1 |
| ASTM D3359 | Method B tape pull | 4B minimum |
| ISO 9227 | Salt spray 500 h, three-coat system | < 2 mm scribe creep |
| ISO 4628-2 | Blister rating after salt spray | No blistering > 2 |
| NORSOK M-501 | System 1 pre-qualification | Pass |
Doctor-blade casting of barium titanate-based dielectric slip for multilayer ceramic capacitors imposes a solvent-release window that is narrower than the viscosity tolerance required in ink compounding. A production slurry commonly contains 100 parts barium titanate powder with a median particle size of 0.2–0.5 µm, 8–14 parts S-LEC BM-SZ, 2–4 parts benzyl butyl phthalate or dioctyl phthalate plasticizer, 0.5–1.5 parts phosphate ester dispersant, and 60–85 parts toluene/ethanol at 60:40–50:50. The slurry is mixed in a high-shear disperser at 25–30 m/s tip speed for 30–45 min, then filtered through a 5 µm absolute filter and vacuum-degassed to remove air bubbles. Brookfield viscosity at 20°C is controlled between 1,500 and 3,500 mPa·s at 20 rpm; higher viscosities produce streaks at the doctor blade, while lower viscosities allow particle settling. Casting uses a doctor blade gap of 150–250 µm on a Mylar carrier at 0.5–2.0 m/min. The three-zone dryer is set at 50°C, 70°C, and 90°C, with the final zone not exceeding 95°C, because rapid surface drying traps toluene and causes pinholes. Green tape thickness after drying is typically 60–100 µm. Tensile properties are measured on free films by ISO 527-3; elongation at break should exceed 10–15% to permit punching and stacking. Binder burnout is verified by TGA in air; decomposition should be complete below 450°C, and residue after 600°C should remain below 50 ppm to avoid carbon contamination in the fired dielectric. The tape is screen-printed with nickel internal electrode paste, laminated under 60–70°C and 50–100 bar, and fired in a reducing atmosphere to produce X7R or X5R MLCC chips.
For pharmaceutical blister lidding stock, S-LEC BM-SZ is applied as a heat-seal lacquer on 20–25 µm hard-temper aluminium foil. The lacquer is dissolved at 15–20 wt% solids in ethanol/ethyl acetate 80:20–70:30; BM-SZ accounts for 60–70 wt% of dry solids, with 10–20 wt% acetyl tributyl citrate or dibutyl sebacate plasticizer and 5–10 wt% polyamide or polyethylene wax slip additive. Coating is performed by direct gravure at 2.5–4.5 g/m² dry weight; lower coating weights create channel leaks at blister flanges, while higher weights increase blocking on the reel. Drying is performed in a three-zone hot-air tunnel at 70°C, 95°C, and 85°C to leave residual solvent below 5 mg/m² as specified by EU 10/2011 packaging migration testing. Heat sealing against PVC or PVDC sheet is conducted on blister machines at platen temperatures of 170–200°C, dwell times of 0.6–1.5 s, and sealing pressures of 0.3–0.6 MPa. Peel strength is measured by ASTM F88 on 15 mm wide strips; pharmaceutical lines typically require a minimum of 3–4 N/15 mm for cold-form and thermoformed blister constructions. The terminal packages are push-through and peel-push blisters for solid-dose oral medicines, where seal integrity is verified by ASTM D3078 dye penetration or vacuum leak testing.
Precision glass and coated optics that pass through CNC grinding, drilling, and edge-seaming operations require a temporary mask with controlled peel adhesion and no silicone transfer. S-LEC BM-SZ is dissolved at 10–14 wt% in ethanol/isopropanol 85:15 and applied by dip coating or flow coating; a forced-air drying step at 60°C for 3–5 min leaves a transparent film of 10–20 µm. Dibutyl sebacate at 5–8 wt% on resin solids reduces peel strength so that the mask can be removed without tearing after machining. Peel adhesion is measured by ASTM D3330 with a 180° peel angle; the target range is 0.2–0.5 N/25 mm on soda-lime float glass. The film resists aqueous grinding coolant and protects coated surfaces from glass chipping during edge grinding. Residual film after removal is checked by water-break-free inspection or contact-angle measurement; contact angle should return to the original substrate value, typically below 20° on cleaned glass. The mask is used for automotive display glass, architectural glazing, and optical filter elements.
For manufacturers compounding interlayer sheet, BM-SZ is combined with 28–38 phr triethylene glycol di-2-ethylhexanoate or dibutyl sebacate plasticizer, 0.1–0.3 wt% UV stabilizer, and 0.05–0.2 wt% adhesion control agent in a high-intensity mixer. The premix is fed to a co-rotating twin-screw extruder with L/D 40–48 and vacuum degassing ports at barrel temperatures of 150–190°C, then calendered to 0.38–1.52 mm sheet. Moisture in the premix must be held at 0.3–0.5 wt%; below 0.3 wt% the melt viscosity increases and edge tearing occurs, while above 0.6 wt% moisture forms bubbles in the sheet. The sheet is conditioned at 20°C and 30–40% RH before glass assembly. Laminated glass is processed in an autoclave at 130–140°C and 12–14 bar for 30–60 min. The final laminate is tested for light transmission and haze by ISO 12543-2, impact resistance by ECE R43, and adhesion by pummel test at -20°C to 40°C. The terminal product is automotive windshields and architectural laminated glazing.
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Polyvinyl butyral resins are random terpolymers of vinyl butyral, vinyl alcohol, and vinyl acetate. S-LEC BM-SZ is assigned to the medium molecular-mass segment of the S-LEC B series, where residual hydroxyl content governs solubility, hydrogen-bonding density, and glass transition temperature. In powder form the material is a white free-flowing solid; a 10 wt% solution in ethanol/toluene remains the conventional process-control medium for viscosity. Because the acetal segment is hydrophobic while the residual hydroxyl group is hydrophilic, BM-SZ disperses in alcoholic, ketone, ester, and glycol ether solvent systems but remains insoluble in water and aliphatic hydrocarbons. The specification envelope for S-LEC BM-SZ typically includes acetalization degree, residual acetyl content, ash, moisture, and low alkali-metal residue. Published numerical limits for this specific commercial grade are not fully reproduced in independent public literature; procurement, formulation, and quality-control decisions should therefore reference the current Sekisui Chemical technical data sheet and certificate of analysis.
BM-SZ is selected when residual sodium and potassium carry risk of dielectric loss or electrode poisoning in co-fired multilayer ceramic capacitors. Tape-casting binder systems require dissolution in MEK/ethanol or toluene/ethanol, pseudoplastic flow under doctor-blade shear, and clean decomposition before sintering. In grade comparisons, BM-SZ is differentiated from standard BM-S primarily by its reduced ionic-residue profile rather than by a large shift in degree of polymerization. Formulators running barium titanate suspensions at solids loadings of 28–35 wt% typically target binder ash below 0.05 wt% by ISO 3451-1:2019 to reduce grain-boundary impurity concentration during firing at 1100–1300 °C. Published data for this specific configuration is limited; full binder-burnout validation requires TGA-FTIR of the actual tape laminate.
On production tape casters, BM-SZ-based slurries are milled in bead mills with yttria-stabilized zirconia media and adjusted to 1500–2500 mPa·s at 10 s⁻¹ before vacuum deaeration. A doctor blade gap of 0.25–0.60 mm is typical for green tape thicknesses from 25 µm to 150 µm after drying. Drying schedules of 60/80/110 °C are used in three-zone tunnels, but solvent release rate depends on the MEK/ethanol ratio, airflow velocity, and web speed. Binder selection influences green density and lamination tack; BM-SZ’s medium molecular mass supports green strength without requiring a higher-viscosity BH-series resin that can reduce slurry solids loading. For large-area tapes, lamination tack is checked by peel adhesion after controlled solvent retention, because excess residual solvent can fuse layers prematurely and create closed porosity during sintering.
Thermogravimetric analysis per ISO 11358-1:2022 at 10 K/min in air shows PVB decomposition in two primary mass-loss regions: side-chain elimination and main-chain oxidation between 200 °C and 450 °C, with carbonaceous residue oxidation continuing above 500 °C. BM-SZ’s low-alkali specification is relevant because sodium and potassium catalyze char formation and can shift the oxidation tail to higher temperatures. In a tape laminate, incomplete burnout produces pyrolytic carbon that can reduce dielectric breakdown strength or create a reducing local atmosphere during firing. TGA-FTIR analysis of binder decomposition off-gasses identifies butyraldehyde, water, carbon monoxide, and carbon dioxide; the ratio depends on oxygen partial pressure. Manufacturers of multilayer ceramic components run binder burnout profiles with dwell at 350–450 °C under flowing air at 5–10 K/min to avoid delamination. Ramp rates above 15 K/min can cause blistering when large-format tapes are stacked, because decomposition gas generation exceeds open porosity permeability.
Compared with S-LEC BM-S, BM-SZ is not selected for significantly higher tensile strength or melt strength. The S-LEC B series uses the first letter to denote molecular mass or solution viscosity class: BL for low, BM for medium, and BH for high. BM-SZ resides in the medium class but adds a reduced ionic-residue attribute. For laminated glass interlayer applications, plasticized PVB film grades are formulated from controlled hydroxyl grades; BM-SZ powder is not a direct interlayer film but may be evaluated as a raw binder where low alkali content is required. Standard PVB film interlayers are tested for tensile elongation by ISO 527-3:2018; raw resin powder is instead tested for hydroxyl content, solution viscosity, moisture, and ash.
BM-SZ is soluble in alcoholic, ester, ketone, and glycol ether solvents. Typical dissolution uses high-shear mixing at 20–25 wt% resin solids and 40 °C. Viscosity stability over 24 h is influenced by moisture and solvent grade; ester solvents can hydrolyze under acidic residues, so neutralized solvent grades are preferred. Filtration through 20–25 µm cartridge filters removes gel particles. The solution is stable when stored under nitrogen and protected from UV; prolonged storage above 40 °C can accelerate acetal hydrolysis and liberate butyraldehyde. In gravure ink formulations, BM-SZ acts as a binder for ceramic pastes and conductive inks; its low residual ionic content may reduce corrosion of silver electrodes when compared with standard PVB grades.
Solution viscosity, not melt flow, is the critical processing parameter for BM-SZ in printing and tape-casting applications. The ethanol/toluene azeotrope is used because it balances hydrogen-bonding capacity and evaporation rate. Viscosity is measured by DIN 53015:2019 or equivalent falling-ball method at 23 °C; target values depend on resin concentration, hydroxyl content, and solvent ratio. For a 10 wt% solution, the medium-viscosity BM class is conventionally controlled in a narrower band than BH grades, but the exact limit must be taken from the manufacturer’s specification. Shear stability is assessed by comparing viscosity before and after high-shear mixing; in practice, a drop greater than 10% after 30 min at 10 000 s⁻¹ indicates chain scission or solvent uptake. This is not a BM-SZ-specific defect; it is a general control for PVB resin solutions.
Moisture pickup above 0.5 wt% causes powder bridging in gravimetric feeders and reduces resin solubility.
Pneumatic conveying of BM-SZ powder should be grounded to control static discharge, and the powder should not be handled near open flames or hot surfaces above 200 °C. The organic powder is combustible; standard organic dust is classified as St2 depending on particle size distribution and moisture, but BM-SZ-specific explosion data are not published in independent literature. Chemical incompatibility exists with oxidizing acids, strong bases, and primary amines. Alkaline conditions hydrolyze the acetal group, while strong acids catalyze depolymerization. Pre-drying at 45–55 °C for 4–8 h in a desiccant dryer is used when moisture-sensitive ceramic formulations require water content below 0.2 wt% by ISO 15512:2019. Glass transition temperature is not commonly used as a lot-release parameter for raw PVB powder, but when measured by ISO 11357-2:2020 it typically falls between 65 °C and 75 °C for medium hydroxyl grades.
| Grade class | Molecular mass/viscosity class | Typical application segment | Residual-ash positioning |
|---|---|---|---|
| BL | Low | Inks, coatings, low-viscosity processing | General |
| BM | Medium | Ceramic tape, printing inks, film raw materials | Standard |
| BM-SZ | Medium | Alkali-sensitive ceramic and electronic binders | Reduced ionic residue |
| BH | High | High-strength films, structural interlayers | General |
The grade comparison above is qualitative and should not replace specification compliance. Where a process conflict arises, such as low-viscosity processing versus high green strength, BM-SZ is evaluated against BM-S and BH-S using a factorial slurry design that varies solids loading, solvent ratio, and dispersant concentration. On a continuous tape caster with a drying tunnel length of 8 m and three-zone temperature control, the practical differences between BM-SZ and standard BM-S appear mainly in residue-sensitive electrical properties rather than in slurry rheology. In contrast, the difference between BM-SZ and BH-S appears in solution viscosity and shear thinning; BH-S typically produces higher green strength but limits solids loading. When the downstream requirement is a low-loss barium titanate tape with silver-palladium inner electrodes, BM-SZ is evaluated because its alkali-metal residue control supports co-firing without severe electrode oxidation.
In printing ink and ceramic paste applications, BM-SZ is typically formulated with plasticizers, wetting agents, and adhesion promoters. The resin content in a ceramic paste is often 5–15 wt% of total formulation, while solvent and dispersant occupy the remaining liquid volume. Paste viscosity is typically controlled between 5 Pa·s and 50 Pa·s at 10 s⁻¹, depending on screen mesh and squeegee speed. BM-SZ contributes pseudoplasticity, and its reduction in ionic impurities is relevant when pastes contact silver terminal electrodes. However, the exact viscosity and residue limits depend on the raw powder batch and should be verified against the certificate of analysis.
For solventborne adhesive and coating formulations, BM-SZ can be combined with epoxy, phenolic, or isocyanate crosslinkers after verifying the residual hydroxyl group availability. Residual hydroxyl values in the medium hydroxyl range provide hydrogen-bonding sites for polar substrates, but the low-alkali specification does not by itself confer greater adhesion. Adhesion performance is tested by ASTM D1876-08(2023) for T-peel adhesion of laminated film systems or by ISO 1827:2022 for rubber-to-fabric adhesion, depending on the substrate. Without a specific bonding interface and cure cycle, no single PVB grade should be selected from viscosity data alone.
Moisture, residual aldehyde, and free acid are batch-release variables that affect storage stability and odor. Free butyraldehyde can generate objectionable odor in printing inks; residual acid accelerates acetal hydrolysis. BM-SZ’s low-alkali profile should be confirmed by ion chromatography or ICP-OES after acid digestion using DIN 51084:2008 or an equivalent multi-element method. The method detection limit for sodium and potassium should be ≤5 ppm when the resin is used in dielectric applications. When data are unavailable for a specific paste or laminate configuration, pilot-scale burnout trials are required before production commitment.
Because BM-SZ is a raw resin rather than a compounded film, mechanical property data for the powder do not translate directly to final film or tape performance. Tensile strength, elongation at break, and tear resistance are generated on compounded specimens after solvent casting or melt pressing. Laboratory film preparation at 180–200 °C under 2–5 bar press pressure permits comparative molecular mass evaluation, but the resulting test pieces are unplasticized and should not be compared with commercial PVB interlayer film. For interlayer-grade performance, plasticized PVB film is tested according to EN ISO 527-3:2018 and adhesion to glass by EN 16613:2019. BM-SZ is not sold as a ready-to-laminate interlayer film.
