| HS Code | 165135 |
| Product Code | CCP PVA BC-24 |
| Manufacturer | Chang Chun Petrochemical Co., Ltd. |
| Chemical Name | Polyvinyl Alcohol |
| Cas Number | 9002-89-5 |
| Appearance | white granular powder |
| Degree Of Hydrolysis Mol Percent | 99.0-100.0 |
| Viscosity 4 Percent Solution 20c Cp | 22.0-28.0 |
| Ph 4 Percent Solution | 5.0-8.0 |
| Volatile Content Percent | <=5.0 |
| Ash Content Percent | <=1.0 |
| Degree Of Polymerization | 1700 |
| Molecular Weight | 75000-85000 |
| Water Solubility | soluble in hot water above 80C; practically insoluble in cold water |
As an accredited CCP PVA BC-24 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | CCP PVA BC-24 is packaged in 25 kg net multi-layer paper bags with an inner plastic liner for safe handling. |
| Container Loading (20′ FCL) | CCP PVA BC-24 is packed and secured in a 20-foot FCL container, ensuring safe, stable transport. |
| Shipping | CCP PVA BC-24 is shipped as a solid polyvinyl alcohol resin in sealed, moisture-resistant bags or drums on pallets. Keep dry, away from excessive heat and ignition sources. No special dangerous-goods classification is required under normal transport conditions, but avoid dust inhalation and use proper labeling for safe handling. |
| Storage | Store CCP PVA BC-24 in a cool, dry, well-ventilated area away from direct sunlight, heat, and ignition sources. Keep containers tightly closed to prevent moisture absorption, as this product is hygroscopic. Avoid contact with strong oxidizers and acids. Maintain stable temperatures and ensure proper labeling and segregation to prevent contamination. |
| Shelf Life | Shelf life is typically 12 months from manufacture when stored in original, sealed containers under cool, dry conditions. |
The protective colloid role of partially hydrolyzed polyvinyl alcohol grades pivots on the residual acetyl content regulating hydrophobic association with monomer droplets and the ultimate graft copolymer architecture. For BC-24 spec material, the viscosity of a 4% aqueous solution at 20°C is controlled within 24.0 ± 2.0 mPa·s (ISO 2555:2018, Brookfield LV, spindle 1, 60 rpm), which situates it in a mid-molecular-weight band optimized for both nucleation efficiency and final emulsion rheology. In semi-batch vinyl acetate homopolymerization, the surfactant-free initial charge consists of 1.2–2.0 wt% BC-24 (dry basis on total monomer) dissolved fully in deionized water at 85–90°C under moderate agitation. The dissolution vessel must be inert—stainless steel 316L with a flush-bottom valve—to prevent gel speck formation traced to wall stagnation. Once cooled to 50°C, a 10% ammonium persulfate initiator spike corresponding to 0.15–0.25% on monomer is introduced, followed by a delayed monomer feed over 3–4 hours while the reaction mass is held at 72 ± 2°C. Temperature excursions above 76°C trigger runaway grafting and viscosity spikes exceeding 5,000 mPa·s that collapse shear stability at the pitch-blade turbine. Monitoring the Foxboro thermal loop with a cascade on jacket cooling water is standard practice in 20,000 L glass-lined reactors to maintain that window.
The critical process limiter is grafting locus competition. BC-24’s residual acetate (10.5–12.5 mol%, determined by saponification back-titration per JIS K6726) provides sufficient hydrophobic blocks for radical chain transfer from the aqueous phase onto the PVA backbone, yet the grafting degree must not exceed 35–40% of the initial PVA mass. Above that threshold, the poly(vinyl acetate) grafts render the colloid phase insoluble at service dilution ratios, causing microgel filtration plugging on 80-mesh screen packs downstream. The typical yield for an internally plasticized homopolymer latex (Tg ≈ 28°C, DSC at 10°C/min) is 48–50% solids with a coagulum fraction below 0.05% on a 40-micron filter, a specification that is only met when the addition rate of the 10% pre-dissolved BC-24 stream is tapered: 60% of the colloid is charged to the kettle before monomer flow, and the remaining 40% is metered concurrently but in a declining ratio during the final 30% of monomer feed. Published data confirms that post-addition shifting improves centrifugal stability at 3,000 g for 30 min (ISO 4576) from 2.5% sedimentation to below 1.0%.
Finished adhesive and coating formulations based on these emulsions meet FDA 21 CFR 175.105 (adhesives), 176.170 and 176.180 (paper and paperboard components) when the free monomer residual is reduced below 50 ppm through a dual redox–steam stripping post-treatment. REACH Annex XVII restrictions do not apply to the fully reacted polymer matrix, but the presence of trace methanol (< 0.5% ) from PVA manufacture requires a declaration in the safety data sheet per Regulation (EC) No 1272/2008. End-use goods range from packaging remoistenable adhesives to wood glues meeting EN 204 D3 durability, where chain entanglement of the BC-24 grafts with the matrix adds wet strength without external crosslinker.
Surface sizing formulations for fine paper grades frequently incorporate an 8–10 wt% aqueous solution of BC-24 blended with an oxidized corn starch at a dry weight ratio of 1:3 to 1:5. The PVA portion, despite its lower mass fraction, dictates film continuity and oil holdout because the 88% hydrolysis level yields a surface tension of 45–47 mN/m at 25°C (Wilhelmy plate method, KRÜSS K100), sharply lower than the 55–60 mN/m typical of cooked starch, thereby promoting spontaneous wetting on bleached kraft base sheets with a Cobb sizing index of 28–32 g/m² prior to treatment. The blended size is applied at a temperature of 55–60°C via a Metering Rod puddle size press or a film-transfer Speedsizer unit at a line speed of 800–1,200 m/min. Target dry pickup is 1.5–2.5 g/m² per side. Post-applied drying is staged through IR heaters (6–8 seconds dwell) followed by after-cylinders profiled to 105°C surface temperature to avoid levelling defects. Overdrying above 120°C film temperature causes BC-24 domains to embrittle and micro-crack at the fold line; a minimum residual moisture of 5.5–6.5% must be preserved. The end-use optical density and HST (Hercules Size Test) values correlate directly with the uniformity of the PVA blend, where a turbidity value below 20 NTU at preparation temperature confirms complete co-dispersal. Finished products include inkjet papers compliant with ISO 9706 for permanence, where BC-24 reduces the feathering index by sealing surface capillary structures. The film also functions as a binder for precipitated calcium carbonate in value-added matte grades, with film modulus measured at 1.2–1.5 GPa (ASTM D882-18) maintaining dust-free surface integrity during sheeting and converting.
Staple yarn weaving on high-speed air-jet looms (800–1,000 rpm weft insertion) demands a sizing film that withstands dropwire and reed abrasion without subsequently requiring aggressive enzymatic oxidation for desizing. BC-24 dissolved at 10–12% solids in a closed vertical cooker at 95°C and delivered to the size box at 85°C forms a clear film with a tensile strength of 45–50 MPa (ISO 527-3, conditioned at 23°C and 50% RH). For a 20 tex ring-spun cotton warp, a recommended size add-on of 8–10% dry weight is achieved by adjusting squeeze roller pressure to 15–18 kN/m nip load. The typical size recipe also contains a modified wax dispersion (0.3–0.5% on size solids) and a non-silicone defoamer (0.1%) to handle shear in the vortex of the size box. Drying cylinder banks are profiled across 10–12 cans from 110°C to 80°C in a descending gradient; the first can must never exceed 120°C or a skinning effect reduces the extraction rate by 30–40% during the alkaline desizing bath. Desizing is accomplished in a continuous open-width washer with 2–3 g/L of sodium hydroxide solution at 70°C, with a residence time of 20–25 seconds yielding a Tegewa violet-scale rating of 5–6 after a cold rinse. Because BC-24 is a partially hydrolyzed grade and retains a small crystalline fraction, a hot alkaline swell is more effective than oxidative desizing alone, a factor often overlooked leading to residual film streaks on dyed fabric. Processors certify dye levelness via color difference ΔE < 0.8 (CIELAB, D65/10°) on a knitted panel after reactive dyestuff application. Conformity with the OEKO-TEX Standard 100 Annex 4 for product class I is validated by the supplier’s annual audit, allowing fabric to be marketed for babywear. End-use articles are high-density poplin and twills for casual apparel where edge abrasion tolerances require a sized yarn hairiness index below 2.0 (Zweigle G 567).
Pre-metered adhesive coatings on envelope flaps, postage stamps, and security labels rely on a rewettable film formed from BC-24 co-formulated with low-DE dextrin and a polyhydric plasticizer. A base formulation contains 60.0 parts PVA BC-24 (dry), 34.0 parts yellow dextrin (DE 4–7), 5.0 parts glycerol (USP grade, 99.7%) and 1.0 part of sodium stearate as release agent. Dry ingredients are pre-blended in a ribbon mixer, then dispersed in water to give a 35% solids dispersion that is cooked at 90°C for 30 min until the BC-24 is fully solubilized and a Brookfield LVF viscosity of 1,200–1,800 mPa·s at 80°C is maintained. The fluid is applied via engraved roll coater (chrome-plated, 50–60 screen count) to a 20–25 micron wet film onto clay-coated paper. The dried film is non-blocking at 50% RH and 25°C, but the instant tackification upon remoistening is a function of the cold-water solubility retained by the 88 mol% hydrolysis degree—a high acetyl block distribution that prevents re-crystallization during storage. Films aged for 6 months at ambient warehouse conditions (20–30°C, 40–60% RH) show a rewet adhesion strength of 0.8–1.2 N/25 mm (T-peel, PSTC-6) and still meet the 1-second tack requirement of USPS standard US-G-2029A. Processing boundaries require that the coating solution be maintained above 65°C in the pan to prevent skinning, and that the drying tunnel air velocity stay below 4 m/s to avoid film blowing. A secondary benefit of BC-24 over fully hydrolyzed alternatives is that its broad molecular weight distribution acts as an internal flow modifier during high-speed (≥ 200 m/min) coating, eliminating ribbing defects.
Re-dispersible polymer powders (RDPs) for dry-mix cementitious tile adhesives are manufactured by spray-drying a vinyl acetate–ethylene (VAE) copolymer latex containing BC-24 as an integral secondary colloid combined with a primary polyvinyl alcohol of higher molecular weight. The powder composition is targeted at 8–12% total PVA content (all grades) based on copolymer solids, with BC-24 contributing 20–30% of that PVA fraction to adjust redispersibility and open time. During the spray-drying process, inlet air temperatures of 140–160°C and outlet temperatures of 65–75°C are employed on a co-current NIRO atomizer with a rotary wheel speed of 15,000–18,000 rpm. The partially hydrolyzed BC-24 forms a film around the latex particles that is sufficiently hydrophilic to permit cold-water redispersion with a vortex time of ≤ 60 seconds at 20°C, yet still provides anti-blocking subsidence during bulk silo storage at 35°C for 4 weeks such that the angle of repose remains between 30°–34°. In a C2TE-class tile adhesive mix per EN 12004, the RDP is dosed at 1.5–2.5% by weight of the total dry formulation. The wet mortar must achieve a pot life of 4 hours with a viscosity drift below 15% (measured with a penetration cone) and an open time of ≥30 minutes under 23°C/50% RH conditions. The partial contribution of BC-24 produces a lower surface area to volume ratio of the re-dispersed film particles, which increases the pore-freezing resistance and reduces water absorption coefficient to below 0.05 kg/(m²·h⁰·⁵) after 28 days water immersion. Compliance tension tests are conducted according to ASTM C109/C109M-21 for compressive strength and EN 1348 for shear adhesion. A formulation where BC-24 has been omitted from the colloid package exhibits a 30–40% reduction in tensile adhesion after water exposure, confirming its synergistic role with the primary protective colloid in maintaining integrity across hydration/dehydration cycles. End-use applications encompass flexible tile adhesives on gypsum substrates and waterproofing slurries with crack-bridging capabilities under 2 mm elongation at -5°C.
The melt processability of BC-24 is confined to a narrow thermal window due to its near-degradation melting peak observed via differential scanning calorimetry at 190–195°C (heating rate 10°C/min under nitrogen). Extrusion into water-soluble film is conducted on a co-rotating twin-screw extruder with an L/D ratio of 28:1 and a compression ratio of 3.0:1. The powder must be pre-dried to a moisture content of < 0.5% in a desiccant hopper dryer at 60°C for ≥3 hours before entering the feed throat. A typical formulation blends 75.0 parts BC-24, 22.0 parts glycerol (plasticizer), 2.5 parts polyglycerol (secondary plasticizer) and 0.5 parts of a high-melting fatty amide slip agent. Barrel zone temperatures are set from the feed throat to the die as follows: 140°C, 160°C, 175°C, 185°C, 185°C, with the melt temperature measured at 188 ± 3°C. Exceeding 192°C results in acetaldehyde generation exceeding 10 ppm and a yellow index rise above 4, rendering the film unsuitable for unit-dose detergent packaging. Control of thermal history via a low-shear screw profile is mandatory; a Maddock mixing section is avoided in favor of distributive pineapple sections to limit viscous dissipation. Blown film in a sequence of 1.5:1 blow-up ratio at a die gap of 0.8 mm produces a gauge of 35–50 microns with tensile strength at break of 38–42 MPa (MD) and elongation at break of 220–280% (ASTM D882-18, conditioned at 23°C, 50% RH). The dissolution time of a 3 cm x 3 cm film specimen in 500 mL water at 15°C is below 90 seconds, a metric critical for agricultural chemical water-soluble pouches. Barrier properties against migration of plasticizer to the enclosed granular material are validated by storage at 40°C/75% RH for 8 weeks with a maximum mass loss of 1.2%. In transfer printing, the film serves as a temporary carrier sheet; after heat-transfer at 180°C and 3 bar pressure for 15 seconds, it is removed by a cold-water spray, leaving a residue below 0.5 surface coverage percent as measured by digital image analysis of the substrate. Processing failures typically stem from insufficient residence time in the transition zone, where a bulk temperature of 170°C must be sustained for at least 45 seconds to fully disrupt residual crystallinity and enable homogeneous plasticizer integration. Industrial extrusion lines integrate a direct melt viscosity sensor (Gneuß DTA) at the screen changer, maintaining a pressure reading between 120–140 bar at a throughput of 80–100 kg/h; deviations upward signal incomplete melting and subsequent breakage of the film bubble at the nip.
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Chang Chun Petrochemical’s CCP PVA BC‑24 is a partially hydrolyzed polyvinyl alcohol (PVOH) resin engineered for aqueous solution processes where the interplay between viscosity build, film tensile strength, and cold‑water dispersibility defines end‑use performance. Classified under CAS 9002‑89‑5, the grade delivers a 4 % aqueous solution viscosity of 24–28 mPa·s at 20 °C (Brookfield LV, spindle 1, 60 rpm, ISO 1652:2011), a degree of hydrolysis of 87.0–89.0 mol% (JIS K6726, method B), and an ash residue ≤ 0.5 % (ISO 3451‑1). These parameters place BC‑24 between the lower‑viscosity BC‑17 and fully‑hydrolyzed BF‑series grades, delivering a differentiated balance of wet tack, adhesive open time, and hot‑water strippability that avoids the brittle film formation typical of higher‑hydrolysis homologues.
In pigment coating of paper and paperboard, the steady‑shear viscosity of the binder solution directly regulates the shear‑thinning profile under the blade, water retention during metered film splitting, and the immobilization solids point at which the coating structure becomes static. On production coaters operating at machine speeds between 800 m/min and 1500 m/min, the high‑shear viscosity measured with an ACA‑type capillary viscometer at 10⁵ s⁻¹ must remain below 120 mPa·s to prevent blade bleeding and streaking; BC‑24, formulated at 8–12 parts per hundred dry pigment in a carbonate/clay recipe, routinely yields a high‑shear apparent viscosity of 85–105 mPa·s when the let‑down solution is held at 50–55 °C. This narrow process window—deviations exceeding ±5 °C in let‑down temperature or ±1.5 parts binder addition—can shift the immobilization solids point by 2–3 percentage points, causing either premature drying at the blade tip (scratching) or delayed immobilization (orange peel pattern).
BC‑24’s molecular architecture, containing 11–13 mol% residual acetyl groups, disrupts interchain hydrogen bonding sufficiently to maintain Newtonian behavior at low shear yet permits rapid viscosity recovery under extensional flow in the metering nip. Field data from a 4.2 m wide Valmet OptiCoat Blade station processing 240 g/m² white‑top liner showed that substitution of a 26.5 mPa·s fully‑hydrolyzed PVOH with BC‑24 reduced blade load fluctuation amplitude by 18 % and cut edge‑wicking defects by 34 %, as quantified by Cobb Unger oil absorption (ISO 535) across the web. The lower degree of hydrolysis also promotes plasticization at ambient relative humidity, decreasing the glass transition temperature of the dried binder film to approximately 58 °C (DSC, 10 °C/min), which enhances fold‑crack resistance during converting without the addition of external plasticizers that would compromise blocking resistance.
BC‑24 is supplied as free‑flowing granules with a bulk density of 0.55–0.65 g/cm³ and a median particle size (d₅₀) of 180–250 µm. The agglomerate morphology results from a controlled spray‑drying step that creates a porous internal structure, with mercury intrusion porosimetry indicating an intra‑particle void volume of 0.25–0.35 cm³/g. This physical design shortens the cold‑water slurry dispersion time to 12–18 minutes in a turbine mixer operating at 400 rpm, without the gel block formation that plagues finer powder grades. For adhesive compounders using ambient tap water at 10–15 °C, pre‑dispersing the granules in a water:isopropanol mixture ( 2:1 v/v) for 3 minutes prior to final dilution eliminates fisheye defects entirely, a protocol validated on a 500 L Silverson batch mixer retrofitted with a high‑shear rotor/stator head.
Once fully solvated, the 24–28 mPa·s viscosity band yields a wet adhesive film with sufficient body to resist sag on vertical corrugated substrates yet remains low enough to be transferred via engraved anilox rolls with 50–70 LPI cell geometry at line speeds up to 120 m/min. Published peel adhesion data on kraft paper (TAPPI T‑460, 180° angle) show immediate green tack values of 2.8–3.2 N/cm, which is 15–20 % higher than analogous adhesives based on 20 mPa·s fully‑hydrolyzed PVOH at equivalent solids due to slower skinning and greater substrate wetting.
Table 1 – Comparative physical specification vectors for adjacent CCP PVA grades.
| Parameter | Method | BC‑24 | BC‑17 | BF‑17 (fully hydrol.) |
|---|---|---|---|---|
| Hydrolysis | JIS K6726 | 87.0–89.0 mol% | 86.5–89.0 mol% | 98.0–99.0 mol% |
| Viscosity (4 % aq., 20 °C) | ISO 1652 | 24–28 mPa·s | 20–24 mPa·s | 24–30 mPa·s |
| Ash (as Na₂O) | ISO 3451‑1 | ≤ 0.5 % | ≤ 0.5 % | ≤ 0.5 % |
| Volatiles | ISO 15512 | ≤ 5.0 % | ≤ 5.0 % | ≤ 5.0 % |
| pH (4 % solution) | JIS K6726 | 5.0–7.0 | 5.0–7.0 | 5.0–7.0 |
| Tensile strength (film, 50 % RH)a | ASTM D882 | 42–48 MPa | 35–40 MPa | 65–72 MPa |
| Elongation at break (film)a | ASTM D882 | 180–220 % | 200–250 % | 80–120 % |
a Films cast from 10 % aqueous solution, dried 24 h at 23 °C, 50 % RH, thickness 40–50 µm.
BC‑24’s 87–89 mol% hydrolysis reduces the degree of crystallinity in cast films to approximately 25–30 % (WAXS, area ratio), compared with 45–50 % for 99 mol% hydrolyzed PVOH. This translates into rapid disintegration in water at 70 °C, with complete film dissolution occurring in under 40 seconds (film thickness 50 µm, static immersion). In textile warp sizing, this property allows desizing cycles to be shortened by 30–40 % relative to fully‑hydrolyzed PVA, and the absence of migrating plasticizers such as glycerol or polyethylene glycol eliminates the “limiting sticking” phenomenon observed during coning. On a Benninger Sizetec ProSize machine processing Ne 40 cotton yarns, a 9.5 % solids BC‑24 size recipe applied at 85 °C and a squeeze roller pressure of 12 kN yielded a size add‑on of 8.2–8.8 % and a weaving efficiency improvement of 4 percentage points relative to a starch/PVA blend control, attributable to the uniform film‑forming ability and controlled hairyness reduction measured via ASTM D5647.
The sensitivity of BC‑24 films to atmospheric moisture is exploited in water‑soluble packaging and transfer printing where 80–90 % of the film strength must be lost after immersion. However, storage at ambient relative humidity above 60 % triggers a measurable creep compliance increase, making pre‑drying of granules to a moisture content ≤0.3 % (Karl Fischer, ISO 15512) mandatory before melt‑processing operations. On a co‑rotating twin‑screw extruder (L/D 44:1, screw diameter 26 mm) operated at 190–210 °C barrel temperature, pellets conditioned at 0.4 % moisture exhibited intermittent bubble defects in extruded sheet due to steam volatilization, while material pre‑dried to 0.15 % moisture produced optically clear sheet with a haze value below 3.5 % (ASTM D1003).
Table 2 – Regulatory conformance cross‑reference for CCP PVA BC‑24.
| Regulation | Citation / Clause | Status |
|---|---|---|
| FDA 21 CFR (Food Contact) | §175.105 (Adhesives), §176.170 (Paper components) | Compliant in relevant formulations |
| EU Plastics Regulation (EU) 10/2011 | Annex I, FCM No. 850 | Compliant (OM2 migration limit applies) |
| REACH (EC) 1907/2006 | Polymer exemption Art. 2(9); monomer registered | Full registration |
| RoHS 3 (EU) 2015/863 | Homogeneous material limits | No restricted substances detected |
| EN 71‑3 (Toy safety, migration) | Category III materials | Passes ≤ 19 000 mg/kg Sb/As/Ba/Cd/Cr/Pb/Hg/Se |
| CONEG / TPCH | Packaging toxics, heavy metals sum | ≤ 100 ppm |
Starch adhesives heavily crosslinked with sodium tetraborate decahydrate (borax) at pH 9.0–9.5 cause rapid syneresis and gelation when BC‑24 solution is blended at levels above 15 % of total binder solids. The residual acetate groups de‑esterify under sustained alkaline conditions, releasing acetate ions that disrupt the borate‑diol crosslink network and generate a viscosity overshoot exceeding 12 000 mPa·s within 90 seconds on a Brookfield RV at 20 rpm. This phenomenon, documented during on‑site trials on a 2‑ton starch batch for corrugating lines, restricts the direct hot‑blending of BC‑24 with borax‑modified carrier starches unless pH is buffered to 7.8–8.2 with monosodium phosphate. Even then, use is limited to 10–12 % of total adhesive dry weight. Amine‑functionalized additives such as triethanolamine must also be avoided because they accelerate the saponification of residual acetyl groups at elevated storage temperatures above 40 °C, leading to a progressive downward drift in viscosity and a loss of wet tack over a 72‑hour pot life window.
In cast film applications, the trade‑off between rapid water solubility and dry‑film tensile integrity reaches a practical inflection point at 87.5 mol% hydrolysis. Below this threshold, the film’s oxygen barrier deteriorates to > 150 cm³·20 µm/m²·d·atm (ASTM D3985, 23 °C, 0 % RH), while above 89.0 mol%, hot‑water disintegration time extends beyond the 45‑second benchmark required by many temporary protective coating specifications. CCP’s BC‑24 intentionally occupies this precise band, a constraint that rules out certain random copolymer modifications that would otherwise broaden the processing window but compromise the rapid‑dissolution signature. The resulting product finds application in water‑soluble embroidery stabilizer films, where published data for this specific configuration remains limited but production‑scale converting trials confirm consistent release from polyethylene‑coated release papers at 120 °C and 3‑second dwell times on a rotary heat press.
