CCP PVA TC-07H'nin

The designation CCP PVA TC-07H identifies a fully hydrolyzed polyvinyl alcohol resin powder manufactured by Chang Chun Petrochemical Co., Ltd. The product is defined by a hydrolysis degree of 98.0–99.0 mol% (saponification value, JIS K6726) and a 4 wt% aqueous solution viscosity of 6.0–8.0 mPa·s at 20 °C determined in accordance with ISO 3105 using a Ubbelohde capillary viscometer. The resin appears as a white to off-white free-flowing powder with a bulk density typically in the range of 0.45–0.65 g/cm³ (tap density ISO 3953). The residual polyvinyl acetate content is consistently below 0.5 wt%, ash content (as Na₂O) does not exceed 0.5 wt%, and volatile matter, predominantly water, lies in the interval 4.0–6.0 wt% when determined by Karl Fischer titration at 130 °C. The primary CAS registry number is 9002-89-5.

Produced via a controlled alcoholysis process that minimises chain scission, CCP PVA TC-07H carries a molecular weight distribution that yields a weight-average molecular weight M_w approximating 85,000–100,000 g·mol⁻¹ (GPC calibrated against pullulan standards). The material is supplied with a certificate of analysis that includes lot-level values for viscosity, hydrolysis, pH (typically 5.0–7.0 in a 4 % solution at 20 °C), and screen residue on a 100-mesh sieve (≤ 0.1 %). This consistency enables direct substitution into existing formulations without re-optimising mixer power draw or drying profiles in industrial adhesive, paper, and textile plants.

How the Hydrolysis Level Above 98 mol% Alters Film Mechanics and Solubility

The near-complete removal of acetate groups eliminates the steric hindrance that otherwise disrupts interchain hydrogen bonding. As a result, films cast from CCP PVA TC-07H develop a high yield stress in tension: tensile strength measured per ASTM D882 on conditioned films (23 °C, 50 % RH) routinely exceeds 55 MPa, while elongation at break falls below 40 %. The glass transition temperature T_g sits near 85 °C (DSC, 10 K/min) and the crystalline melting point appears at approximately 228 °C. These thermal benchmarks contrast sharply with the partially hydrolysed grades in the CCP BP and BF series, where residual acetate units depress T_g into the 50–70 °C range and reduce cold-water solubility. CCP PVA TC-07H does not dissolve in water below 50 °C; complete dissolution requires sustained shearing at 85–95 °C for at least 30 minutes. This solubility threshold limits its utility in ambient-temperature potting compounds but provides inherent water resistance in cured adhesive layers, with swelling ratios in deionised water at 25 °C of less than 50 wt% over 24 hours.

When the dissolution vessel is a jacketed high-shear disperser equipped with a rotor-stator head, the powder should first be suspended in cold water (10–20 °C) at a concentration of 4–10 wt% to prevent lump formation, after which the temperature is ramped to 90 °C at 2 °C/min. Viscosity development during the heat-up phase is non-linear: a pronounced incline occurs once the slurry passes 75 °C, and incomplete hydration above that threshold can produce persistent microgel specks that act as stress concentrators in cast films.

Extended exposure of the dry powder to relative humidity exceeding 60 % causes measurable agglomeration; pre-drying at 60–80 °C in a fluid-bed dryer is recommended if the storage atmosphere cannot be controlled below 50 % RH. The dried resin should be processed within 8 hours to avoid re-absorption of atmospheric moisture that shifts the volatile content by 0.5–1.0 wt%.

Viscosity Drift Under Constant Shear — A Processing Constraint

Aqueous solutions of CCP PVA TC-07H display appreciable temporal viscosity decline when held under continuous mechanical shear at elevated temperature. In a laboratory Brookfield RVT measurement (Spindle No. 3, 20 rpm, 90 °C) on a 6 wt% solution, a viscosity drop of 8–12 % can be recorded over 60 minutes. This shear-thinning history is partially recoverable on cooling if the chains have not undergone permanent degradation, but for applications requiring precise rheological control—such as slot-die coating of release films—shear history must be standardised. Comparative data from production-scale dissolvers with 500 L vessel volume show that maintaining a constant specific power input of 0.5–0.8 kW/m³ limits chain scission to less than 3 % reduction in number-average molecular weight, as verified by subsequent SEC analysis.

Because the viscosity specification band of 6.0–8.0 mPa·s is relatively narrow, inter-lot variability is held below ±0.5 mPa·s, which translates into a dry-film thickness variation of less than ±1.5 µm when coating a 8 wt% solution through a 200 µm doctor-blade gap on a polyethylene terephthalate substrate. This is a critical parameter for barrier films used in oxygen-sensitive packaging where the oxygen transmission rate (OTR) through a 15 µm dry PVA layer at 23 °C, 0 % RH is documented near 0.5 cm³/(m²·day·atm) (MOCON OX-TRAN method, ASTM D3985).

Differences from lower-viscosity fully hydrolysed grades such as CCP PVA TC-05 (viscosity 4.5–5.8 mPa·s) become most evident in suspension polymerisation protective-colloid roles, where TC-07H’s higher molecular weight yields a lower critical dosage to achieve a given particle-size distribution in vinyl acetate emulsion systems. In a standard batch emulsion polymerisation of 100 parts vinyl acetate monomer with 60 parts water and 0.2 parts potassium persulfate, replacing 2.5 parts of TC-05 with the same loading of CCP PVA TC-07H reduces the mean particle diameter (D₅₀, dynamic light scattering ISO 22412) from approximately 1.8 µm to 1.1 µm and raises the emulsion’s high-shear viscosity (cone-and-plate at 10,000 s⁻¹) by 20–35 %. However, this smaller particle size also increases the specific pigment-binding surface area of the dried film, which must be factored into the binder demand when formulating water-based inks.

When the Protective Colloid Function Demands a Surface Tension Balance

Because CCP PVA TC-07H exhibits a surface tension of aqueous solutions in the range of 46–49 mN/m at 25 °C for a 1 wt% concentration (Du Noüy ring, ASTM D1331), it serves as a moderate surfactant in emulsion polymerisation. The surface activity, however, is less than that of partially hydrolysed grades such as CCP PVA BP-17 (43–46 mN/m), meaning that additional non-ionic surfactants may be needed when targeting sub-micron latexes. The difference in acetate content also shifts the cloud point of aqueous solutions: for TC-07H no cloud point is observed below boiling, whereas BP-17 solutions turn turbid above 35 °C. This thermal behaviour directly affects the handling of residual PVA in wastewater, as the high-hydrolysis polymer is less prone to phase separation during cooling but produces a more persistent gel layer in ultrafiltration modules if the concentration exceeds 0.5 wt%.

A well-documented operational boundary involves borate-ion interactions: contact with borax or compounds releasing borate ions causes instantaneous gelation through didiol borate crosslinking. For this reason, the product cannot be used in combination with borate-substituted starch or boric acid-activated thickeners unless the two components are kept separate until the application moment—a constraint that has led some corrugating-board manufacturers to prefer polyvinyl acetate homopolymer emulsions instead.

Upstream, the powder’s handling characteristics on a pneumatic conveying line with a loading ratio of 3–5 kg/kg and a conveying velocity of 20 m/s demand attention to the minimum ignition energy (MIE), reported to be 10–30 mJ for PVA dust clouds (St 1 dust explosion class). Consequently, all transfer equipment must conform to ATEX 114 (Directive 2014/34/EU) zone 21/22 requirements, with antistatic hoses and grounding resistance below 10⁶ Ω.

One Reaction Vessel, Two Hydrolysis Grades — How Product Selection Shifts Process Economics

In plants that alternate between producing fully hydrolysed and partially hydrolysed PVA-based formulations, the switchover cost is dictated by tank cleaning and solubility characteristics. CCP PVA TC-07H leaves a significantly thicker dried film on vessel walls compared to partially hydrolysed grades because its high crystallinity promotes skin formation at the liquid-air interface during cooling. Cleaning-in-place cycles must therefore include a prolonged hot-water wash (90 °C for 40–60 minutes) followed by a dilute caustic flush (0.1% NaOH, 30 minutes) to fully remove residue. This step adds approximately 1.5 hours to the turnaround time when compared with a BP-series product, a non-trivial penalty when multi-campaign scheduling is tight.

Conversely, the high hydrolysis level of TC-07H improves the solvent resistance of the final coating against methylene chloride, acetone, and ethyl acetate, broadening its use in solvent-based primer tie-coats for polyolefin adhesion. Peel strengths measured on corona-treated polypropylene substrates after a 0.2 mm dry film application and 180° peel test (ASTM D903) can exceed 4.0 N/cm, whereas analogous coatings prepared with partially hydrolysed PVA seldom exceed 2.0 N/cm because the acetate groups plasticise the film under solvent attack.

Applications that exploit these property differences include warp sizing for high-twist cotton yarns, where the CCP PVA TC-07H film imparts abrasion resistance during high-speed weaving (loom speeds above 800 rpm). In contrast, TC-07H is rarely chosen for hot-melt extrusion without a plasticiser because its melting point of 228 °C sits dangerously close to the onset of thermal degradation around 200–210 °C. Twin-screw compounding with at least 15–25 wt% of a high-boiling plasticiser such as pentaerythritol or trimethylolpropane brings the processable temperature window down to 170–190 °C, but care must be taken to limit residence time at the die to <180 seconds to prevent crosslinking that generates black specks. When these processing constraints are observed, the compound complies with FDA 21 CFR 175.105 for indirect food contact adhesives if the plasticiser also carries the requisite clearance.

Film recyclability and environmental disintegration follow ISO 14851 for aerobic biodegradation in an aqueous medium: the high hydrolysis form achieves 60–70 % mineralisation within 60 days when inoculated with activated sludge, a rate comparable to the partially hydrolysed grades, although the initial lag phase is longer by 5–10 days due to the slower dissolution of crystalline domains. Published data for this specific configuration in the presence of common sizing auxiliaries (waxes, starches) is limited; field-scale composting trials are recommended before making biodegradability claims on finished goods.

Storage specifications require a dry, ventilated warehouse at <30 °C and a maximum relative humidity of 60 %. Under these conditions, the material remains within specification for 12 months from the date of production marked on the bag. Moisture regain after the bag is opened proceeds at approximately 0.3 wt% per hour at 70 % RH, so partial bags must be heat-sealed immediately after use.