CCP PVA BP-26

What determines the minimum effective dosage of partially hydrolyzed poly(vinyl alcohol) in vinyl acetate semi-continuous emulsion polymerization?

A recurring point of process failure in 500–2,000 L stainless-steel semi-batch reactors producing poly(vinyl acetate) homopolymer emulsions is the abrupt onset of coagulum accumulation on baffle surfaces and impeller hubs when the protective colloid dosage falls below the critical surface coverage threshold. CCP PVA BP-26, with its intermediate block character imparted by 87–89 mol% alcoholysis, provides sufficient interfacial activity to stabilize growing polymer particles without generating foam defects, while the residual acetate sequences permit controlled grafting of PVAc chains during the initial seed stage. Typical polymerization uses a freshwater initial charge containing the entire PVA portion at 3.0–5.5 % based on total vinyl acetate monomer, dissolved under agitation at 85–90 °C for 45 min. After cooling to 68 °C, a small monomer fraction (5–8 %) is introduced together with a potassium persulfate initiator solution (0.15–0.25 % on monomer) to generate the seed latex; the remaining monomer is metered over 3.5–4.5 h with the jacket controlled to maintain the batch at 78–80 °C. The ratio of grafted PVA to free PVA in the final latex, determined by selective solubilization in isopropanol/water mixtures, falls in the range of 22–32 %, correlating strongly with the Brookfield viscosity plateau. Routine compliance for emulsion-based adhesives intended for indirect food-contact packaging requires the dried film to meet extractives limits under FDA 21 CFR §175.105 and the total volatile organic compound emission profile to satisfy the German AgBB scheme, where the sum of TVOC after 28 days must remain below 1.0 mg/m³. Post-polymerization, residual monomer is stripped by steam or vacuum distillation at 65 °C until free VAc content falls below 0.3 %; the emulsion is then cooled, neutralized with sodium bicarbonate to pH 4.5–5.5, and passed through a 100-µm bag filter. Finished products span D3 woodworking adhesives (EN 204), paper-to-paper laminating adhesives for sack and envelope manufacture, and water-based school glues meeting heavy-metal release limits per EN 71-3. When the protective colloid concentration dips below 1.8 %, coagulum levels exceed 0.3 % on wet emulsion and must be separated by basket centrifugation, causing unacceptable yield losses.

PVA BP-26 dosage (wt% on VAc)	Mean particle size (nm, ISO 22412)	Brookfield viscosity (mPa·s, LVF #3, 12 rpm)	Wet coagulum retained on 45 µm sieve (%)	Mechanical stability (ASTM D1417-16, 15 min at 14 000 rpm)
2.0	420±45	2400	0.48	Slight sediment, no phase separation
3.5	285±30	6200	0.07	No visible sediment
5.0	195±20	11 500	0.02	No change, viscosity drift ±3 %

PVA BP-26 dosage (wt% on VAc)

Mean particle size (nm, ISO 22412)

Brookfield viscosity (mPa·s, LVF #3, 12 rpm)

Wet coagulum retained on 45 µm sieve (%)

Mechanical stability (ASTM D1417-16, 15 min at 14 000 rpm)

2.0

420±45

2400

0.48

Slight sediment, no phase separation

3.5

285±30

6200

0.07

No visible sediment

5.0

195±20

11 500

0.02

No change, viscosity drift ±3 %

Surface strength agent replacement in carbonate-filled woodfree paper grades

Alkali-swellable rheology modifiers and synthetic latexes that dominate modern paper surface treatments lose effectiveness when calcium carbonate filler content exceeds 25 % in the base sheet because they are unable to bridge the pH-driven charge reversal on the filler-matrix interface. In such alkaline making conditions, a film-forming surface size based on CCP PVA BP-26, co-applied with anionic oxidized corn starch through a metered size press, restores IGT dry pick strength without sacrificing bulk or opacity. The surface size liquor is prepared by dissolving BP-26 in demineralized water at 3.0–4.5 wt% solids at 95 °C for 30 min, then blending it with cooked starch to a final total solids of 8–11 % and a PVA-to-starch dry ratio of 15:85 to 25:75. Application proceeds on a film-transfer metering unit (Voith SpeedSizer or equivalent) where the pond depth is controlled by a rotating metering rod, depositing a dry coat weight of 0.6–1.2 g/m² per side. Sheet-fed printing trials on 80 g/m² woodfree copy paper reveal an increase in critical wax pick number from 14A to 18A (TAPPI T459) and a dry IGT pick resistance exceeding 2.8 m/s measured per ISO 3783:2015 using medium-tack ink. The surface-sized paper destined for food-contact applications complies with FDA 21 CFR §176.170 (Table 2, paper and paperboard in contact with aqueous and fatty foods) and the relevant BfR Recommendation XXXVI, where overall migration into simulant D (olive oil) at 40 °C for 10 days must remain under 10 mg/dm². The terminal product range includes multipurpose copy paper run on high-speed xerographic lines, pigmented inkjet media where the PVA film functions as a dye mordant, and base stock for extrusion-coated liquid packaging board where an interlayer adhesion above 150 N/15 mm (ASTM D1876) is required before PE lamination.

When a Steinemann starch adhesive batch is dosed with partially hydrolyzed polyvinyl alcohol to elevate green tack on high-speed single-facers

Single-facer speeds consistently exceeding 300 m/min during production of B-flute corrugated board require green bond strength to develop within 50–80 ms of nip compression, a regime where native wheat starch adhesives exhibit pseudoplastic behavior insufficient to prevent flute-tip springback and micro-delamination at the combiner roll. Incorporation of CCP PVA BP-26 as a functional modifier into the two-component Steinemann adhesive recipe—added directly to the primary carrier paste after full gelatinization or blended as a 10 % pre-cooked solution into the raw starch slurry—supplements the tack profile without extending gel points beyond the critical 71–73 °C range measured by a Carri-Med rheometer. The dosing level is kept between 2.5 % and 4.0 % on dry starch weight, calculated on the total batch solids of 22–26 %. Process setup on a BHS or Mitsubishi corrugator involves maintaining the glue dam temperature at 29–32 °C and setting the rider roll gap to apply 8–12 g/m² (dry basis) of adhesive to the flute tips. Wet pin adhesion values rise from 2.8 N/cm to 4.5 N/cm when tested according to TAPPI T821 immediately after the double-backer, while the edge crush of the finished board (ISO 3037) improves by 12–18 % at identical board grammage. The adhesive layer must comply with sections of FDA 21 CFR §176.170 applicable to components of paper and paperboard in contact with aqueous and dry food; specific migration of vinyl acetate monomer from the finished box must remain below the detection limit of 0.01 mg/kg simulant. End products are heavy-duty single-wall and double-wall shipping containers, recyclable pizza boxes, and fruit tray punnets where cold-chain moisture resistance is a prerequisite.

For water-based flexographic printing on corrugated containers and multi-wall sacks, the binder must simultaneously wet high-surface-area organic pigments, resolubilize within seconds on the anilox roll to prevent dried-in screen plugging, and later disintegrate completely in the alkaline repulping bath. CCP PVA BP-26, dissolved to a 12–16 % stock solution, serves as both the grinding medium resin and the let-down vehicle at a total binder loading of 8–12 % of the finished ink formulation. During the pigment dispersion stage, a horizontal bead mill (Netzsch MiniCer or equivalent) charged with 0.6–0.8 mm yttria-stabilized zirconia beads processes a pre-mix of BP-26 solution, phthalocyanine blue pigment (C.I. PB 15:3), and a polymeric dispersant until a grind fineness of <5 µm is reached on a Hegman gauge (ISO 1524:2020). The millbase is then let down with additional BP-26 solution, a defoamer, and an amine pH adjuster to a final viscosity of 30–45 s (DIN 4 mm cup at 23 °C). The dried ink film (2–4 µm thickness) must comply with the EuPIA Guideline on Printing Inks applied to the non-food-contact surface of food packaging and satisfy the Swiss Ordinance RS 817.023.21 Annex 6 positive list, where poly(vinyl alcohols) appear under CAS 9002-89-5 without specific migration limit. The printed board undergoes a hot alkali soak test in 1 % NaOH at 50 °C where the binder layer dissolves in less than 30 s, enabling complete fibre recovery during recycling. Finished print products range from e-commerce boxes with single-color lettering to four-color process-printed shelf-ready packaging that passes ASTM D5264 Sutherland rub resistance testing at ≥100 cycles without visible ink transfer.

Protective colloid matrix for ethylene-vinyl acetate copolymer spray-dried powders

Spray-drying of vinyl acetate–ethylene copolymer dispersions stabilized exclusively with low-molecular-weight surfactants inevitably leads to partial coagulation at the atomizer tip and poor redispersion of the resultant powder in alkaline cementitious media. Adding CCP PVA BP-26 as a secondary protective colloid to the dispersion prior to atomization—typically at 6–10 % based on polymer solids—confers thermal protection to the latex particles during droplet drying and prevents irreversible hydrophobic agglomeration during storage. The process begins with a VAE base latex (50–55 % solids, Tg near –5 °C) which is cooled to 20–25 °C and blended with a separately dissolved BP-26 solution (10 % concentration, preserved with 0.2 % benzisothiazolinone biocide). The mixture is pumped to a co-current pressure-nozzle spray dryer (GEA Niro FSD or equivalent) with an inlet air temperature of 150–175 °C and outlet temperature maintained at 70–80 °C; the nozzle pressure is adjusted to 60–80 bar to yield a particle size distribution centered at 80–120 µm. An anticaking agent, typically kaolin or precipitated silica at 2–5 %, is metered into the collection cyclone to ensure free-flow characteristics. The resulting redispersible polymer powder must satisfy the requirements of EN 12004-1:2017 for cementitious tile adhesives when formulated at 3.0 wt% addition; the resistance of the final blend of powder with Type I Portland cement is governed by EN 1348 tensile adhesion tests after water immersion and heat ageing. Compliance with GEV Emicode EC1 Plus (emission class for very low-emitting building products) is confirmed by chamber testing per ISO 16000-9, where TVOC values after 3 days must fall below 750 µg/m³. End products include flexible C2 S1 tile adhesives, exterior insulating render base coats, and self-smoothing floor screeds where early shrinkage and edge curl are mitigated by the polymer’s film-forming capability.

Protective colloid type (spray dryer feed)	28d dry tensile adhesion (EN 1348, MPa)	Water immersion adhesion retention (%)	Powder angle of repose (°)	Blocking resistance (50 °C, 24 h, rating 1-5)
BP-26 (8 % add-on)	1.40 ±0.08	82	29	4 (no caking)
BP-17 (fully hydrolyzed, 8 % add-on)	0.95 ±0.12	63	34	3 (minor lumps break under finger pressure)
Surfactant-only control (0 % PVA added)	0.70 ±0.18	49	42	1 (fused mass)

Protective colloid type (spray dryer feed)

28d dry tensile adhesion (EN 1348, MPa)

Water immersion adhesion retention (%)

Powder angle of repose (°)

Blocking resistance (50 °C, 24 h, rating 1-5)

BP-26 (8 % add-on)

1.40 ±0.08

4 (no caking)

BP-17 (fully hydrolyzed, 8 % add-on)

0.95 ±0.12

3 (minor lumps break under finger pressure)

Surfactant-only control (0 % PVA added)

0.70 ±0.18

1 (fused mass)

Polyvinyl alcohol grade BP-26, designated under the CCP (Chemically Crosslinkable Polymer) portfolio, is a 26 µmol/g residual acetate, partially hydrolyzed (87–89 mol%) granular resin with a weight-average molecular weight (M_w) of 85,000–97,000 g/mol as determined by size-exclusion chromatography calibrated against narrow-dispersion PVA standards. Aqueous Brookfield viscosity of a 4 wt% solution at 20 °C spans 24–30 mPa·s, positioning it in the intermediate molecular weight band between fully hydrolyzed film grades and low-viscosity specialty grades used for emulsion stabilization. Unlike fully hydrolyzed PVA (>98 mol%), which requires dissolution temperatures exceeding 90 °C under high-shear mixing, BP-26 achieves complete solubilization in deionized water at 70–80 °C with moderate turbine agitation, reducing thermal history on heat-sensitive co-formulants. The acetate block distribution, characterized via ¹³C NMR triad analysis, exhibits a statistically random pattern, which distinguishes it from blocky partially hydrolyzed grades—a structural feature that directly influences cold-water solubility, interfacial tension at the air–water boundary, and hydrogen-bonding density in cast films.

How does BP-26 perform in continuous water-soluble film casting compared to higher molecular weight PVA?

On a pilot-scale cast film line equipped with a 300 mm wide polished chrome belt and multi-zone forced-air drying at 80/100/120 °C, BP-26 at 18 wt% dope concentration yields 35–40 µm dry film with a tensile strength of 42 MPa (ASTM D882, 50 mm/min crosshead speed) and elongation at break of 310%. The critical processing window for belt release occurs at a residual moisture content of 6–8 wt%; deviation below 5% induces edge curling and microcracking due to excessive hydrogen-bond densification. In comparison, a fully hydrolyzed grade with M_w of 125,000 g/mol demands an elevated dope temperature of 90 °C to avoid gel particles and results in a more brittle film (elongation 160%) under identical drying profiles, limiting its utility in deep-draw thermoformed packaging where puncture resistance at seam corners is paramount. BP-26 film dissolves completely in agitated water at 10 °C within 45 seconds (MSTM 205 method), whereas the high-MW grade requires 120 seconds, a difference attributed to reduced crystalline domain interconnectivity from the randomly placed acetate groups disrupting poly(vinyl alcohol) syndiotactic sequences. On a production-scale BOPP film lamination line, delamination events dropped from 7 per 1,000 linear meters to less than 1 when switching from a standard partially hydrolyzed PVA with 12 mPa·s viscosity to BP-26 as an interlayer adhesion promoter in a waterborne barrier coating system, validated by inline optical inspection at 300 m/min line speed.

Hot-melt extrusion of BP-26 with a 10 wt% polyethylene glycol (400 g/mol) plasticizer on a co-rotating twin-screw extruder (L/D = 40, screw speed 250 rpm, barrel profile 170/180/190/200 °C) produces a thermoplastic PVA strand with a melt flow index of 18 g/10 min at 210 °C under 2.16 kg load (ISO 1133-1:2022). Die swell is reduced by 22% relative to a fully hydrolyzed PVA grade processed under the same conditions, attributable to the internal plasticization effect of residual acetate groups disrupting interchain packing. This enables precision profile extrusion for biodegradable plant stakes and tubular mandrels used in lost-core composite molding, with overall dimensional tolerance held to ±0.15 mm on a 5 mm diameter rod. Moisture uptake after 24 hours at 50% RH and 23 °C stabilizes at 3.2 wt% (ASTM D570), above which surface tack develops and processing is not recommended without vented barrel vacuum devolatilization at -0.08 MPa gauge.

Adhesive formulation limits and borate gelation thresholds

When compounded into a high-speed paperboard tube winding adhesive at 12% solids alongside 3 wt% (on PVA dry basis) of a biobased glyoxal crosslinker, BP-26 delivers a Brookfield LVT open time of 28 seconds on uncoated kraft board at 55 °C nip temperature. The immediate tack force, measured via a 180° peel test (TLMI L-IA-2), reaches 4.2 N/25 mm, exceeding the 3.5 N minimum required for high-speed spiral winding at 80 m/min. However, the presence of borate ions—commonly introduced through recycled process water or borated starch extenders—poses a gelation risk. At pH > 8.2, the critical borate concentration for gel formation in a 10 wt% BP-26 solution is 0.04 wt%, as evidenced by an abrupt loss tangent transition from 1.8 to <0.1 on a strain-controlled rheometer (cone-and-plate geometry, 1 Hz, 0.5% strain). Below pH 7.8, gelation does not occur at borate levels up to 0.5 wt%, making pH buffering with 0.1 M sodium acetate a standard countermeasure on lines using recycled wash water. This sensitivity is more pronounced than in fully hydrolyzed PVA grades, where the lower density of free 1,3-diol units reduces crosslink density, and formulators switching from a fully hydrolyzed grade to BP-26 must pre-screen all incoming starch streams for borate content via curcumin spot test or ICP-OES.

In textile warp sizing for polyester-cotton blends, BP-26 is applied from a 9 wt% bath at 85 °C on a slasher run at 60 m/min. Weaving efficiency on a rapier loom operating at 550 picks/min improved from 82% to 94% when substituting a native corn starch/PVA blend with a 100% BP-26 size, attributed to a lower coefficient of friction (0.18 vs 0.26 against stainless steel heddle eyes) and reduced shed droppings. Desizing on a continuous open-width washer with 70 °C water achieved 99.2% removal in three wash boxes, confirmed by iodometric staining, compared to five boxes required for starch-based sizes—a direct energy and water consumption reduction of 35% per linear meter of fabric processed.

Comparative low-shear viscosity development with competing partially hydrolyzed grades
Property	CCP PVA BP-26	Standard PH-PVA (12 mPa·s)	High-MW PH-PVA (40 mPa·s)
Hydrolysis (mol%)	87–89	86–89	87–90
Viscosity (4% aq., 20 °C, mPa·s)	24–30	11–14	38–42
Cold-water solubility (10 °C, sec)	48	55	95
Film elongation at break (%)	310	260	380
Adhesive open time (sec, kraft)	28	22	35
Borate gelation threshold at pH 8.5 (wt%)	0.04	0.06	0.03

When PVA BP-26 replaces carboxymethyl cellulose in paper coating applications

In a blade-coating trial on lightweight coated paper (LWC, 48 g/m² base sheet) running at 1,200 m/min, a binder system composed of 6 parts BP-26 and 8 parts styrene-butadiene latex per 100 parts ground calcium carbonate (60% < 2 µm particle size) produced a dry coating weight of 8.5 g/m² per side. The IGT surface strength measured on an AIC2-5 tester with medium-viscosity oil was 1.8 m/s, a 20% gain over a 14-part carboxymethyl cellulose (DS 0.7)/latex reference formulation. Rheologically, high-shear viscosity measured with a capillary viscometer at 100,000 s^-1 was 38 mPa·s for the BP-26 coating color, versus 52 mPa·s for the CMC-containing color, enabling a reduction in wet-on-dry coating splitting defects at the trailing edge of the blade. Delta gloss at 75° (TAPPI T480) improved from 8 units to 4 units, indicating a more uniform surface topography. The critical water retention value measured via the ÅA-GWR gravimetric device dropped from 95 g/m² to 78 g/m², reducing base-sheet wetting and resultant fiber picking on the offset printing blanket during HP Indigo digital-to-conventional hybrid runs. However, calcium ions leached from the ground calcium carbonate in the presence of glucono-delta-lactone sequestrant above 0.2 wt% total formulation solids induce a reversible flocculation of BP-26 by salting out; this operational boundary necessitates daily titration of soluble calcium via EDTA complexometry to maintain levels below 120 ppm in the recirculation tank.

Emulsion polymerization stabilizer across vinyl acetate homopolymer and low-VOC architectural coatings

BP-26 used as a protective colloid in a 45% solids vinyl acetate homopolymer emulsion batch (semi-continuous monomer feed, 85 °C, potassium persulfate initiator) at 2.5% on monomer yielded a final latex with a mean particle size of 1,120 nm (dynamic light scattering, z-average) and a shear viscosity of 1,800 mPa·s at 20 rpm. The grafting efficiency of vinyl acetate onto the PVA backbone, inferred from Soxhlet extraction in acetone over 24 hours, reached 38%; this high level of grafting contributes to shear stability measured as no coagulum after 10 minutes of high-shear mixing at 9,000 rpm on a Silverson L5M rotor-stator head. In contrast, a low-molecular-weight fully hydrolyzed PVA (4 mPa·s) produced latex with broader polydispersity (PDI 0.28 vs 0.14 for BP-26) and a sediment volume of 1.8 mL upon accelerated ageing at 50 °C for 14 days. The resulting architectural paint formulated to 33% pigment volume concentration (PVC) and < 50 g/L VOC with a coalescent-free binder system passed 5,000 cycles scrub resistance (ASTM D2486) against the specification minimum of 3,000 cycles. Storage stability showed a delta Stormer rise of 6 KU after one month at 40 °C, within acceptable limits for shelf-stable formulations. Limitations arise when the pH drifts below 4.0 due to acidic pigment dispersants, causing progressive esterification between PVA hydroxyls and free acetic acid released from the colloid; a dedicated post-add of 0.15 wt% sodium bicarbonate buffer pre-admixed in the letdown stage prevents viscosity drift.

Published data for BP-26 in barrier coatings for paper-based food packaging under FDA 21 CFR 176.170 components of paper and paperboard in contact with aqueous and fatty foods remain limited to internal company reports, though the base polymer is listed in the inventory. Migration testing performed according to EU Regulation (EC) No 1935/2004 using Tenax® simulant for 10 days at 40 °C indicated overall migration below 2 mg/dm², well under the 10 mg/dm² limit, with specific detection of vinyl acetate monomer below the 12 µg/kg detection limit by HS-GC-MS. This grade is not recommended for direct polyethylene terephthalate (PET) bottle hot-fill adhesion without a primer layer of ethylene-acrylic acid copolymer; direct laminates exhibited delamination within 72 hours at 60 °C and 95% RH due to mismatched hydroexpansion coefficients, as measured by blister test adhesion energy decreasing from 85 J/m² to < 10 J/m².

Differential thermal, crystalline, and lifecycle indicators against competitive polyols

Thermal transitions, crystallinity, and oxygen transmission rate for BP-26 versus typical fully hydrolyzed and blocky grades
Measured parameter	CCP PVA BP-26	Fully hydrolyzed (98.5 mol%)	Blocky partially hydrolyzed
T_g (DSC, midpoint, dry, °C)	62	78	59
Melting peak T_m (°C)	186	228	172
Enthalpy of fusion (J/g)	47	82	34
XRD crystallinity index (%)	31	58	25
Oxygen transmission rate (25 µm film, 23 °C, 0% RH, cm³/m²·day·atm)	0.8	0.2	1.6
OTR at 50% RH	6.4	2.1	13.8

The lower crystallinity of BP-26 relative to fully hydrolyzed grades explains its superior elongation and cold-water solubility but also results in higher oxygen permeability under humid conditions, limiting its standalone barrier use without a secondary coating of PVdC or metallization. Its random acetate distribution imparts a narrower melting endotherm (half-height width 11 °C) compared to the blocky grade (24 °C), enabling tighter thermal process control during extrusion lamination onto temperature-sensitive substrates. Cradle-to-gate global warming potential calculated per ISO 14040/14044 for vinyl acetate monomer-based PVA production places BP-26 at approximately 2.1 kg CO₂-eq/kg, similar to other partially hydrolyzed grades, though the elimination of an alkaline methanolysis step for full hydrolysis reduces caustic soda consumption by about 0.15 kg/kg compared to fully hydrolyzed material.

HS Code	600843
Product Name	CCP PVA BP-26
Chemical Type	Partially Hydrolyzed Polyvinyl Alcohol
Cas Number	9002-89-5
Appearance	White to off-white granular powder
Hydrolysis Degree	87.0 - 89.0 mol%
Viscosity 4 Aqueous Solution 20 C	24.0 - 28.0 mPa·s
Ph 4 Aqueous Solution	5.0 - 7.0
Volatile Content	≤ 5.0 wt%
Ash Content	≤ 0.5 wt%
Residual Acetyl Group Content	11.0 - 13.0 mol%
Degree Of Polymerization	Approximately 1300
Water Solubility	Soluble in water with heating for complete dissolution

Packing	CCP PVA BP-26 is supplied in 25 kg multi-wall paper bags with polyethylene liner, ensuring safe handling and moisture protection.
Container Loading (20′ FCL)	Container Loading (20′ FCL): CCP PVA BP-26 is packed into a 20-foot full container load, secured and sealed for transport.
Shipping	CCP PVA BP-26 (polyvinyl alcohol) ships as non-hazardous material in multi-layer paper bags, commonly 25 kg net weight. Protect from moisture, humidity, and direct sunlight during transit. Keep well-ventilated to avoid dust accumulation. Secure pallets properly; no special dangerous-goods restrictions apply, but handle with clean, dry equipment to preserve quality.
Storage	Store CCP PVA BP-26 in a cool, dry, well-ventilated area in its original, tightly sealed container. Protect from moisture, direct sunlight, and high temperatures. Keep away from ignition sources and oxidizing agents. Avoid generating dust during handling. Ensure proper labeling and containment to prevent spills.
Shelf Life	Shelf life is typically 24 months from manufacture when stored in original, unopened containers in a cool, dry place.

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