| HS Code | 954202 |
| Molecular Weight Mw | 50000-70000 g/mol |
| Hydroxyl Content | 30-34% |
| Butyral Content | 66-70% |
| Vinyl Acetate Content | 0.5-2.5% |
| Viscosity 20 C 5 Ethanol Solution | 20-40 mPa·s |
| Glass Transition Temperature | 90-100°C |
| Specific Gravity | 1.07-1.09 |
| Refractive Index | 1.49 |
| Moisture Content | <0.5% |
| Particle Size | 95% min through 35 mesh |
| Apha Color | <80 |
| Solubility | Soluble in ethanol, methanol, DMF, and other organic solvents |
As an accredited B20HX Chang Chun PVB Resin factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | B20HX Chang Chun PVB Resin is packaged in sealed multi-layer bags, net weight 25 kg each, ensuring moisture protection. |
| Container Loading (20′ FCL) | 20′ FCL container loaded with B20HX Chang Chun PVB Resin, securely packed in drums on pallets, ready for transport. |
| Shipping | B20HX Chang Chun PVB Resin ships as non-hazardous solid resin in sealed, moisture-proof bags or drums. Keep dry, avoid heat/open flames, and store in ventilated areas. Use covered containers to prevent contamination. Standard truck, rail, or ocean freight is suitable with proper labeling and handling. |
| Storage | Store B20HX Chang Chun PVB Resin in a cool, dry, well-ventilated area away from heat, open flames, and direct sunlight. Keep containers tightly sealed to prevent moisture absorption and contamination. Maintain stable temperatures, ideally below 25°C, and avoid high humidity. Separate from oxidizing agents and incompatible materials. Follow local regulations for safe handling. |
| Shelf Life | Store in a cool, dry place; typical shelf life is 12–24 months from production under proper sealed conditions. |
Chang Chun B20HX resin is compounded with triethylene glycol bis(2-ethylhexanoate) (3GO) at addition levels between 20 phr and 38 phr before interlayer sheet extrusion for laminated safety glass. The hydroxyl content reported on the B20HX certificate of analysis controls plasticizer compatibility because higher hydroxyl retention increases hydrogen bonding capacity, raises tensile modulus, and reduces plasticizer migration toward the glass interface. For architectural interlayers, the target residual moisture in the compounded melt is maintained below 0.2 wt% by a desiccant dryer with a −40 °C dew point and an outlet air temperature between 60 °C and 70 °C. Sheet extrusion on a co-rotating twin-screw extruder with an L/D ratio of 30:1 to 40:1 is held at melt temperatures between 170 °C and 190 °C; higher melt temperature or extended residence time accelerates acetic acid evolution from residual acetate groups and causes yellowing. The calendered sheet is wound with interleaving and conditioned to 0.4–0.5 wt% moisture before glass lay-up. Moisture content above 0.5 wt% produces steam bubbles at the glass–interlayer interface during autoclave processing, while excessively dry sheet below 0.2 wt% can shift pummel adhesion values and increase impact brittleness. On production-scale calender lines with slot die widths above 2000 mm, edge bead thickness variation is monitored because edge beads must be trimmed and if excessive can alter winding density and downstream conditioning uniformity. Laminated assemblies are deaired by nip rollers or vacuum bags, then processed in an autoclave at 1.1–1.3 MPa and 135–150 °C for 60–120 min. The pressure vessel must maintain uniform edge pressure because PVB flows under autoclave conditions and seals the laminate edge. For automotive glass, the interlayer must pass ECE R43 and ANSI Z97.1 requirements; architectural projects are specified under EN ISO 12543-2 and ASTM C1172. Tensile properties of the free film are determined according to ISO 527-3 or ASTM D638-14. Adhesion control salts, typically magnesium or potassium salts, are added at trace levels to maintain pummel adhesion in the 3–7 range for architectural glazing; automotive side-lite configurations generally target 5–8 on the same scale. Operational boundaries include ambient humidity above 60% RH, which requires sealed storage and short conditioning windows, and incompatibility with amine-functional silanes in edge seals, which can cause localized haze at the laminate periphery.
In a two-component phosphoric acid-activated wash primer, component A is prepared by dissolving B20HX at 7–9 wt% in a solvent blend of isopropanol, n-butanol, and a minor aromatic fraction. The balance of component A typically includes zinc tetroxychromate at 5–10 wt%, talc or extenders at 2–5 wt%, and additional alcohols to maintain spray viscosity. Component B is a 10–20% dilution of 85% phosphoric acid in isopropanol or water. The two components are mixed at a 4:1 volume ratio immediately before spray application; pot life at 23 °C is generally limited to 8–24 h because phosphoric acid reacts with the PVB hydroxyl groups and slowly insolubilizes the binder. The acid activator etches zinc-coated steel and aluminium, generating a phosphate conversion layer that improves adhesion of the subsequent epoxy or polyurethane primer. Applied dry film thickness is held between 5 μm and 12 μm; heavier films create a weak boundary layer because the phosphoric acid remains partially unreacted and can attack the topcoat interface. Chromate-bearing wash primers assigned to MIL-C-8514-class formulations provide salt-spray resistance, but REACH Annex XIV authorization requirements restrict the use of zinc tetroxychromate and strontium chromate in EU production. Reformulated systems replace hexavalent chromium with zinc phosphate, aluminium triphosphate, calcium molybdate, or organic corrosion inhibitors. B20HX is selected in such systems for acid resistance and rapid solvent release; hydroxyl content determines the crosslink density after acid-induced dehydration. Adhesion is evaluated by ASTM D3359-17 method B cross-hatch tape pull, and corrosion performance is screened by ASTM B117-19 or ISO 9227:2022 neutral salt spray exposure. A limitation of B20HX-containing wash primers is their sensitivity to high humidity during solvent evaporation; application at relative humidity above 80% RH can cause moisture blush and loss of intercoat adhesion on steel substrates. If the topcoat is a moisture-curing polyurethane, residual phosphoric acid can inhibit tin-catalyzed cure at the interface, so the wash primer must be overcoated within the window specified by the topcoat supplier, typically between 30 min and 24 h.
When B20HX is dissolved in oxygenated solvents, the solution viscosity and drying gradient on non-absorbent polyolefin film are governed by the resin’s hydroxyl and acetate content. A flexographic or gravure ink vehicle based on B20HX at 8–15 wt% solids in an ethanol, n-propanol, and ethyl acetate mixture displays shear-thinning behaviour suitable for chambered doctor-blade metering. Pigment concentrates are milled with the resin solution on a three-roll mill or bead mill until a Hegman gauge reading of 5–7 is reached. The final ink is adjusted to a B4 cup viscosity of 18–25 s at 25 °C for narrow-web flexo presses; gravure units may require lower viscosity in the same solvent system. B20HX contributes adhesion to corona-treated BOPP, PET, and aluminium foil through polar hydroxyl and acetal groups. In lamination inks, the PVB binder must be compatible with the subsequent solventless or solvent-based polyurethane adhesive; excessive residual hydroxyl can consume isocyanate crosslinker and reduce interlayer adhesion. The printed substrate is dried at surface web temperatures between 50 °C and 65 °C, with residual solvent below 5 mg/m² as measured by gas chromatography before lamination. For retort-grade flexible packaging, the printed structure is tested after lamination by ASTM F88/F88M-21 peel strength and by visual inspection after retort at 121 °C for 30 min. The oxygenated solvent system is incompatible with high-molecular-weight chlorinated polyolefin adhesion promoters that require aromatic or aliphatic hydrocarbon diluents; therefore, B20HX-based inks are not recommended for untreated polypropylene film without a primer. Published data for high-speed closed-chamber flexo presses with anilox volumes above 8 cm³/m² are limited; pilot trials are required to balance pigment loading, solvent release, and ink transfer on high-surface-energy films.
Tape casting suspensions for multilayer ceramic substrates incorporate B20HX as the primary green-body binder in a two-solvent system based on methyl ethyl ketone and ethanol. The binder content is calculated on the dry ceramic powder mass; typical bench-scale ranges are 5–12 wt% B20HX, 1–4 wt% plasticizer such as butyl benzyl phthalate or a phthalate-free polyethylene glycol alternative, 0.5–2.0 wt% dispersant, and 25–35 wt% total solvent. The slurry is milled for 16–24 h in a ball mill with 3–5 mm zirconia media, then degassed under vacuum to remove trapped air before tape casting. A doctor blade gap of 100–500 μm yields green tape thicknesses from 20 μm to 250 μm after solvent evaporation. Viscosity of the deaired slurry is checked at 25 °C with a Brookfield viscometer according to ASTM D2196-20; standard low-shear viscosity windows depend on the caster geometry but frequently range from 800 mPa·s to 2500 mPa·s at 12 rpm. Binder removal is the critical thermal process. Thermogravimetric analysis of PVB-based tape in flowing air generally shows oxidative decomposition onset near 220 °C, with complete removal by 450–600 °C. For alumina and BaTiO₃ systems, the temperature ramp between 250 °C and 400 °C is held below 1 °C/min to prevent blistering, carbon residue, and camber in sintered substrates. Incomplete binder burnout leaves residual carbon that shifts dielectric loss in co-fired ceramic capacitors; therefore, forced-air batch furnaces or continuous tunnel furnaces are programmed with controlled exhaust during the burnout zone. B20HX is suitable only when the declared ash content and residual metal profile meet the capacitor or substrate manufacturer’s contamination limits; this must be confirmed against the certificate of analysis because published data on B20HX-specific burnout residue is limited. In multilayer ceramic capacitor tape casting, the green tape is blanked, screen printed with nickel or silver-palladium internal electrodes, stacked, and laminated at 50–80 °C under 10–20 MPa before binder burnout. Green strength is screened by tensile testing of punched strips according to ISO 527-3 using 25 mm gauge length specimens. Storage of cast tape at 45–50 %RH for more than one week can cause moisture pick-up that changes lamination tack and springback. If the tape becomes too dry, plasticizer migration from the binder phase to the ceramic particle surface produces embrittlement and edge chipping during blanking. These batch-to-batch variances are evaluated by monitoring binder glass transition via differential scanning calorimetry at 10 K/min.
Blends containing B20HX and a heat-reactive phenolic resole are milled on a two-roll mill at 70–90 °C to produce adhesive films for aluminium-to-wood and steel-to-wood structural lamination. The PVB component acts as a film former and toughness modifier; loading levels between 10 phr and 25 phr relative to the resole solids are screened. Lower PVB content improves heat resistance but reduces peel strength; higher PVB content increases flexibility and moisture sensitivity. The supported adhesive film is cured between platens at 150–180 °C under 0.5–1.0 MPa for 20–40 min. Joint performance is assessed by ASTM D1002-10 lap shear in aluminium-to-aluminium bonded coupons. B20HX should not be combined with amine-based hardeners because residual phenolic methylol groups and PVB acetate hydrolysis products form amine salts that weaken interfacial adhesion. Published data for B20HX in this specific configuration is limited; screening under the end user’s cure profile is required.
The vacuum lamination cycle for B20HX-based encapsulant sheet is constrained by the resin’s moisture uptake, melt flow, and adhesion to photovoltaic glass and backsheet. The sheet is pre-dried at 45–55 °C for 12–24 h in a desiccant dryer before module lay-up. Lamination in a single-chamber vacuum laminator is conducted at platen temperatures of 140–160 °C, with an evacuation phase of 5–8 min and a pressing phase of 10–15 min. The encapsulant must fill cell gaps and cell string spacing without excessive edge squeeze-out; edge squeeze exceeding 2 mm beyond the glass edge is generally unacceptable because it creates a path for moisture ingress and contamination. Adhesion to tempered low-iron glass is influenced by the glass surface cleanliness and the concentration of adhesion-promoting silane in the sheet formulation. Modules are tested under IEC 61215-2:2021 for thermal cycling, damp heat, and humidity freeze; insulation resistance and wet leakage current are evaluated under IEC 61730:2023. Lamination is terminated after the backsheet bonding stage; no post-cure is required because PVB is a thermoplastic material and does not require the peroxide-driven crosslinking step used with EVA encapsulants. Storage of unlaminated B20HX sheet at ambient humidity above 60% RH causes moisture absorption that produces steam defects during lamination. The material is also incompatible with carboxylic acid anhydride-based adhesion promoters at melt temperatures because rapid acetal ring-opening reactions reduce optical clarity. Damp-heat aging at 85 °C and 85% RH for 1000 h under IEC 61215-2:2021 is used to detect interfacial adhesion loss and backsheet delamination. B20HX-based encapsulant sheets typically show higher water absorption than polyolefin encapsulants, so edge seal design and backsheet moisture vapour transmission rate are critical variables. Optical qualification requires transmittance above 88% in the 380–1100 nm range on low-iron glass laminates; haze is measured according to ASTM D1003-21. Process excursions above 165 °C can cause bubble formation if residual moisture exceeds 0.1 wt% in the encapsulant sheet, a threshold that is lower than for architectural interlayers because photovoltaic laminates do not use thick interlayer mass to absorb the same amount of steam. The use of a single-chamber vacuum laminator with membrane pressure below 0.98 bar cannot fully wet the cell surface; full contact is required before the pressing phase begins.
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Chang Chun Petrochemical Co., Ltd. supplies B20HX as a polyvinyl butyral resin grade specified for interlayer extrusion, primer and adhesive formulation, and ceramic green-tape binder systems. The grade is sold as a free-flowing powder or granulate; the lot certificate of analysis reports residual polyvinyl alcohol and acetyl content, volatile level, ash, and melt-viscosity data because the supplier does not publish a complete ISO-style datasheet for every grade. Polyvinyl butyral resins in the B20HX class are condensation products of polyvinyl alcohol and butyraldehyde, retaining hydroxyl groups that control glass adhesion and plasticizer compatibility. The typical glass transition temperature range is 68–78°C when measured by differential scanning calorimetry at 10°C/min under ISO 11357-2. Processing and storage boundaries are governed by moisture pickup and thermal decomposition; the resin should be stored at ≤ 25°C and ≤ 50% RH, and pre-dried to ≤ 0.3 wt% moisture before melt processing. In formulation, B20HX differs from low-hydroxyl PVB grades by its higher hydroxyl content and greater hydrogen-bonding potential to silicate glass, which increases adhesion but also raises equilibrium moisture sensitivity unless plasticizer and processing conditions are controlled.
In production-scale compounding, B20HX is typically processed on a counter-rotating twin-screw extruder with an L/D ratio of 40:1 or higher, with barrel temperatures from 160°C in the feed zone to 200–215°C at the die. Melt pressure is maintained between 12 MPa and 20 MPa depending on screw geometry and throughput. The resin exhibits shear-thinning behavior with a power-law index in the range of 0.25–0.45 at 200°C over a shear-rate window of 100–500 s⁻¹; therefore high-shear screw sections can generate excessive viscous heating. If melt temperature exceeds 220°C, acetal ring-opening releases butyraldehyde and produces yellowing in the compound. If the feed zone is operated below 160°C, unmelted powder may compact and cause feed blockage.
Moisture control is the primary processing constraint. At ambient relative humidity above 60%, B20HX absorbs surface moisture quickly, and resin above 0.3 wt% moisture can generate bubbles in calendered sheet and delamination in laminated-glass autoclaves because steam evolves at the glass–interlayer interface. Pre-drying in a desiccant dryer with a dew point of −20°C or lower at 60 ± 5°C for 4–6 h is required for humid production sites. A vented extruder barrel with vacuum below −0.08 MPa is used to strip residual moisture and low-molecular-weight volatile oligomers before the die. Batch-to-batch variation in residual hydroxyl content of ±1.5 mol% can shift equilibrium plasticizer demand by 2–4 parts per hundred resin; incoming quality control for interlayer production therefore includes hydroxyl titration and melt mass-flow rate testing according to ISO 1133-1:2022 at 190°C and 2.16 kg. The melt mass-flow rate for this class of extrusion-grade PVB is typically 5–15 g/10 min, though B20HX lot values may vary.
Table 1 lists the commercial specification envelope for a PVB resin of the same class as B20HX. The values are class-typical rather than guaranteed lot-specific values; Chang Chun lot certificates may report narrower ranges and supplier-specific methods for polyvinyl butyral content and solution viscosity.
| Parameter | Determination method | Class-typical range | Notes |
|---|---|---|---|
| Volatile content | ISO 3251 | ≤ 3.0 wt% | 105°C, 3 h |
| Ash content | ISO 3451-1 | ≤ 0.5 wt% | 600°C |
| Melt mass-flow rate | ISO 1133-1:2022 | 5–15 g/10 min | 190°C, 2.16 kg |
| Bulk density | ISO 60 | 0.30–0.50 g/cm³ | Free-flowing powder or granulate |
| Glass transition temperature | ISO 11357-2 | 68–78°C | DSC, second heating, 10°C/min |
| Hydroxyl content | Supplier titration | 18–23 mol% | Relative to polyvinyl alcohol |
Published data for B20HX specifically is limited; the supplier should be requested to supply the lot certificate before scaling to production. Mechanical properties of the compounded interlayer or primer are product-specific and must be measured on the final formulation rather than inferred from resin powder data.
Laminated safety glass interlayers are the highest-volume application for B20HX-class PVB resins. The resin is dry-blended with a plasticizer such as triethylene glycol di-2-ethylhexanoate or dibutyl sebacate at 20–45 wt% of the total compound. The hydroxyl groups of the resin form hydrogen bonds with the silicate surface of float glass; higher hydroxyl content increases adhesion but also raises equilibrium moisture uptake. Without adequate pre-drying and autoclave pressure, moisture trapped in the interlayer can form steam pockets and white haze at the interface during autoclave cycles below 135°C or 1.2 MPa. Production lines use two-stage autoclaves operating at 135–150°C and 1.2–1.5 MPa for 30–60 min, after a pre-press calendar step at 50–80°C to remove trapped air. Interlayer thickness is commonly 0.38 mm, 0.76 mm, or 1.52 mm, and the conditioned interlayer should hold moisture below 0.4 wt% before layering.
Mechanical performance of the finished interlayer is tested according to ISO 527-3 at 23°C; class-typical tensile strength is 20–30 MPa with elongation at break above 150%. Optical haze is measured by ISO 14782, and architectural glazing producers commonly reject interlayer with haze above 0.5% when measured with a spectrophotometer. Laminated glass produced with B20HX interlayers must meet the safety glazing requirements of ISO 12543-2 or the regional automotive standard ECE R43; pummel adhesion values are evaluated under ECE R43 Annex 4 or equivalent internal method, with target ranges adjusted for glass type and plasticizer level. In comparison with ethylene-vinyl acetate interlayers, PVB interlayers of equal thickness typically show higher glass adhesion and higher shear modulus at service temperatures, but require autoclave pressure and more rigorous moisture control; published data for B20HX specifically in this comparison is limited.
B20HX can also be dissolved in solvent blends for ceramic green-tape casting. A representative slurry contains 55–65 wt% oxide powder, with the resin solution at 5–10 wt% of the liquid phase. The slurry is cast onto a moving polyester carrier at wet-film thicknesses of 100–300 μm and dried at 60–80°C to a residual solvent level below 0.5 wt%. Thermogravimetric analysis according to ISO 11358-1 shows binder burnout in air between 350°C and 450°C. Ash content above 0.5 wt% is detrimental in dielectric tape, so each B20HX lot should be screened by ISO 3451-1 before use in multilayer ceramic capacitors. The higher solution viscosity of B20HX relative to low-molecular-weight PVB ink grades requires a reduction of 2–3 percentage points in nonvolatile content to maintain the same tape-casting viscosity.
The selection of B20HX instead of an alternative PVB grade, ethylene-vinyl acetate copolymer, or thermoplastic polyurethane is governed by adhesion, moisture resistance, melt viscosity, and solvent-release behavior. Table 2 summarizes class-level comparisons relevant to industrial selection. The B20HX column reflects typical PVB extrusion resin properties; it is not a lot-specific certificate. Published data for the exact B20HX grade is limited, so side-by-side validation on production equipment is required when replacing another polymer.
| Attribute | B20HX-class PVB | Low-hydroxyl PVB | Ethylene-vinyl acetate interlayer |
|---|---|---|---|
| Hydroxyl content | 18–23 mol% | 9–15 mol% | Not applicable |
| Plasticizer requirement | 20–45 wt% | 30–50 wt% | No external plasticizer required for standard interlayer grades |
| Tensile strength of film | 20–30 MPa per ISO 527-3 | 15–25 MPa per ISO 527-3 | 10–20 MPa per ISO 527-3 |
| Typical processing | Twin-screw melt compounding plus autoclave | Twin-screw melt compounding plus autoclave | Vacuum lamination 140–160°C, no high-pressure autoclave |
| Moisture sensitivity | High; pre-dry to ≤ 0.3 wt% | Moderate; pre-dry to ≤ 0.3 wt% | Moderate; requires dry storage |
| Optical haze | ≤ 0.5% per ISO 14782 when controlled | ≤ 0.5% per ISO 14782 when controlled | Often higher than PVB after aging |
B20HX is used as the film-forming polyvinyl butyral component in two-pack wash primers for abrasive-blasted steel, aluminum, and glass. The resin is dissolved at 5–10 wt% in an alcohol-ketone solvent system and combined with a phenolic resin and phosphoric acid catalyst. Dry-film thickness is typically 5–15 μm. The hydroxyl groups on the PVB backbone participate in room-temperature crosslinking with the phenolic methylol groups; full cure may require 7–14 days at 23°C, but forced cure at 80°C for 30 min shortens the cycle. Solvent retentiveness is a known limitation: if the solvent evaporation curve does not match the spray-booth flash time, residual ethanol or methyl ethyl ketone can cause topcoat craters and poor intercoat adhesion. Spray viscosity is controlled to 20–25 s with a Ford #4 cup at 25°C according to ASTM D1200; because B20HX yields a higher solution viscosity than lower-molecular-weight PVB grades, solids may need to be reduced by 2–3 percentage points.
Adhesion is verified by ISO 4624 pull-off and ASTM D3359 cross-cut. On profiled carbon steel, dry-film pull-off strength above 5 MPa is commonly required before the topcoat. Residual phosphoric acid above 0.5 wt% of the wet formulation can cause flash rust and intercoat delamination; acid level is therefore titrated and corrected for each batch. The resin should not be formulated as a one-pack system with amine-based epoxy hardeners unless stabilized, because residual acid and PVB hydroxyls can slowly react and produce storage viscosity rise. B20HX differs from PVB grades used for printing inks by its higher solution viscosity and stronger adhesion to glass and metal, but its chlorine-free composition and lower inorganic residue also make it suitable for electronic-grade priming where ionic contamination must be controlled.
For quality assurance of compounded B20HX compounds, tensile properties are measured according to ISO 527-1:2019 or ASTM D638-14, flexural properties according to ISO 178, and impact strength according to ISO 179-1 or ASTM D256. The raw resin is not typically used as a structural material without plasticizer; plasticized PVB compounds are strain-rate and temperature dependent, so modulus values measured at 23°C and 1 mm/min crosshead speed are not valid for design at −20°C or 50°C. Dynamic mechanical analysis by ISO 6721-1 is used to map the glass transition and plateau modulus of the final interlayer or primer film. B20HX class materials show a pronounced damping peak near 30–40°C after plasticization, but exact peak location depends on plasticizer type and loading.
Incoming resin quality for production-scale users should be tracked against the certificate of analysis, with particular attention to hydroxyl content, volatile level, and melt-viscosity consistency. A shift of ±1.5 mol% in hydroxyl content can alter plasticizer demand and autoclave adhesion; a shift of ±5% in melt mass-flow rate can require barrel-temperature adjustments on a twin-screw line. Producers using B20HX in laminated glass interlayers often condition resin and plasticizer at 20–25°C and 20–30% RH before blending to limit moisture absorption during open handling. Equipment contact surfaces should be stainless steel or aluminum; copper and copper alloys are avoided where color stability is critical because trace metal ions can accelerate thermal degradation. Avoid prolonged storage at high ambient temperature because resin particles can block or sinter when surface temperature exceeds 50°C.
Regulatory compliance for B20HX is end-use dependent. The resin can be accompanied by a supplier declaration confirming that it is not intentionally formulated with substances of very high concern above the 0.1 wt% communication threshold under REACH Regulation (EC) No 1907/2006. RoHS Directive 2011/65/EU, amended by (EU) 2015/863, applies to homogeneous materials in electrical and electronic equipment; the selected plasticizer and stabilizer package must be assessed for lead, cadmium, mercury, hexavalent chromium, PBB, and PBDE limits. Finished laminated glass interlayers are specified under ISO 12543, and visual transmittance and haze are evaluated with ISO 12543-6. Published data for B20HX in direct food-contact applications is limited; any formulation intended for FDA 21 CFR or comparable food-contact use must be confirmed with Chang Chun Petrochemical Co., Ltd. against the final compounded product.
