Chang Chun CCP B-20TX

Chang Chun CCP B-20TX is supplied as a partially hydrolysed polyvinyl alcohol with a 4 % aqueous solution viscosity at 20 °C in the 24–30 mPa·s band and an alcoholysis degree of 86–89 mol% when determined by JIS K6726. In shuttleless weaving operations with loom speeds above 650 picks/min, the grade is used as the primary film former in warp size mixes for ring-spun cotton, polyester/cotton staple yarn, and filament polyester, where it reduces warp hairiness at the reed and heald frames. A representative 1 000 L size-mix batch for 20 tex ring-spun cotton combines 70 kg CCP B-20TX, 30 kg oxidized tapioca starch, and 4 kg saponified wax, adjusted to 12.0 % size solids by mass. The powder is suspended in cold water at 25–30 °C under 200–300 rpm propeller agitation for 10–15 min, heated to 90–95 °C, and held for 30–45 min until the solution becomes clear. The size-box temperature is maintained between 60 °C and 70 °C in a double-dip, double-nip slasher fitted with 8–14 kN squeeze rolls; the target size add-on is 8.0–9.0 % for 20 tex cotton and 5.5–7.0 % for 14.8 tex polyester/cotton, measured by loss on ignition after the size box.

The 86–89 mol% hydrolysis window supplies lower crystallinity than fully hydrolysed PVA, which allows the size film to absorb reed impact without brittle fracture while maintaining dry film tensile strength above 30 MPa when cast and conditioned per ASTM D882-18. At 60 °C size-box hold, solution viscosity remains stable for at least 8 h, but extended residence beyond 12 h can develop shear-induced gel bodies; installation of a 100 µm inline strainer before the size box prevents structured gel from reaching the nip. Desizing of the woven fabric is performed with 0.2–0.5 g/L amylase enzyme at 70–80 °C for 10–20 min, followed by 2.0–3.0 g/L sodium hydroxide scour at 90 °C for starch and wax removal. The process is limited by the grade’s moderate molecular weight, which requires cooking above 90 °C to achieve full dissolution; cold-water slurrying below 20 °C without agitation will form lumps that are difficult to disperse later. Terminal substrates cut and sewn from these warps include denim, poplin shirting, sateen bedding, and technical workwear.

Why Is the 86–89 mol% Hydrolysis Fraction Preferred as a Protective Colloid in VAE Reactors?

In vinyl acetate–ethylene emulsion polymerization, CCP B-20TX is charged as the primary protective colloid at 3.0–5.5 parts per 100 parts vinyl acetate monomer by mass before pre-emulsification. The residual acetate groups provide greater affinity for the growing poly(vinyl acetate) surface than fully hydrolysed PVA, while the 24–30 mPa·s viscosity contributes sufficient hydrodynamic volume to suppress particle coalescence during the exotherm. The polymerisation is run in a 10–30 m³ pressure vessel with 120–160 rpm agitation, using a hydrogen peroxide–ferrous sulfate redox cycle at 55–75 °C and 0.4–0.8 MPa ethylene pressure. The colloid is dissolved separately at 10 % solids in demineralized water at 90–95 °C, cooled to 40 °C, and fed ahead of the initial monomer charge to avoid thermal shock. During polymerization, vinyl acetate grafts onto the PVA backbone; the grafted fraction reduces colloid interfacial mobility and anchors the stabilizer to the particle surface, narrowing the laser-diffraction size distribution to a D₉₀ below 1.2 µm under ISO 13320:2020. The resulting VAE emulsion is shear-thinning and remains stable against viscosity drift for 6 months at 20–25 °C, but freeze-thaw stability is not intrinsic and requires 2.0–5.0 wt% propylene glycol or urea in export formulations that transit sub-zero conditions.

For wood adhesive compounding, the PVA-stabilized poly(vinyl acetate) homopolymer is adjusted to 45–55 % solids and blended with 2.0–5.0 wt% plasticizer, 0.2–0.5 wt% preservative, and 0.5–1.5 wt% defoamer. Beech, birch, and pine cold-press assemblies bonded with this emulsion at 0.6–0.8 MPa require 20–40 min press time and develop fibre-tearing bonds after 24 h conditioning at 23 °C and 50 % RH. In paper converting, the same adhesive is roller-coated at 4–8 g/m² wet film and dried at 105–115 °C; peel adhesion to polyethylene-coated board remains above 1.5 N/15 mm in 90° peel mode per ASTM D903-98(2017). Compliance for indirect food-contact adhesive seams relies on FDA 21 CFR 175.105; the grade itself is evaluated as a component only when the formulated adhesive meets extraction limits. The main operational boundary in adhesive conversion is the viscosity increase below 5 °C, which alters roller transfer on high-speed lamination lines.

Paper Surface Sizing and Size-Press Starch Extension

On flooded-nip and metered size presses producing copy paper, kraft liner, and white-top testliner, CCP B-20TX is added at 2.0–8.0 parts per 100 parts oxidized tapioca or corn starch on a dry basis. The PVA stream is cooked separately at 10–12 % solids in a steam-jacketed tank at 90–95 °C for 25–35 min, then metered into the starch slurry after the starch has been cooked at 95–98 °C and cooled to 60–65 °C. The size-press bath is controlled at 6.0–10.0 % total solids and 55–65 °C, with nip viscosity held at 20–60 mPa·s at 60 °C. The addition permits a starch solids reduction of 0.5–1.5 percentage points without sacrificing surface strength, reducing picking on open-draw paper machines running above 1 200 m/min. Cobb absorption per ISO 535:2023 remains below 25 g/m² on unsized base paper after surface sizing, while IGT surface strength per ISO 3783 increases by 15–30 % relative to a starch-only control. The system is incompatible with borax at the size press: borate ions crosslink residual diol units in the PVA and produce a gel that plugs the nip piping and doctor blades.

The terminal paper grades produced through this route include multipurpose office paper, flexographic preprint liner, and white-top testliner for corrugated packaging. Because the grade is partially hydrolysed, it re-dissolves more readily in broke repulping than fully hydrolysed PVA, but mills must control repulper pH between 6.0 and 8.5 to prevent alkaline hydrolysis of residual acetate groups and subsequent foaming. Compliance for packaging food contact is evaluated under EU Regulation (EC) No 10/2011 only after migration testing of the finished board; the PVA component is not an automatic compliance pass. The limiting condition on high-speed machines is the interaction between PVA film and calcium carbonate filler at pH above 8.5, which increases wetting and may reduce internal sizing efficiency.

When B-20TX Is Cast into Cold-Water Soluble Film Without Post-Dehydration

Cast film produced from CCP B-20TX uses an aqueous compound containing 12–18 wt% PVA, 1.0–3.0 wt% glycerol or sorbitol, 0.5–1.5 wt% nonionic surfactant, and 0.05–0.2 wt% antifoam on total wet mass. The solution is degassed at −0.08 MPa for 30–60 min and coated on a chrome-plated belt or PET carrier at 8–14 m/min. Drying is staged from 70 °C entering to 110 °C final zone over 6–10 min, leaving 6–10 wt% residual moisture in the film. Because the grade retains 86–89 mol% hydrolysis, the film dissolves readily in water at 20 °C, with complete dissolution in 30–60 s under 100 rpm agitation when tested in a 2 L beaker using a dissolution procedure adapted from JIS K6726. Tensile strength of the conditioned film is in the 20–35 MPa range with elongation at break of 100–200 % per ASTM D882-18; the exact values depend on plasticizer loading and residual moisture.

Primary terminal uses are cold-water soluble laundry bags for contaminated hospital linen, release liners for embroidery, and single-dose agricultural chemical sachets. High-humidity storage above 60 % RH causes blocking and should be prevented with sealed PE overwrap. Published data for this specific grade in concentrated detergent unit-dose film is limited; the relatively low hydrolysis degree gives rapid cold-water solubility but lower alkaline resistance than fully hydrolysed film grades, so the material is not interchangeable with 98–99 mol% hydrolysis detergent-grade PVA without reformulation. Compliance for the film in packaging applications requires migration testing under EU Regulation (EC) No 10/2011 or compliance with FDA 21 CFR 177.1670 for the finished article, not the raw resin alone.

A tape-casting binder formulation for alumina substrates and multilayer ceramic capacitor dielectric layers uses CCP B-20TX at 2.0–5.0 wt% of dry ceramic powder, dissolved at 8–14 wt% solids in demineralized water and blended with 0.5–1.0 wt% ammonium polyacrylate dispersant and 2.0–4.0 wt% polyethylene glycol plasticizer on dry ceramic mass. The slurry is ball-milled at 60–70 % of critical speed for 18–24 h until Hegman fineness reaches 4–6 µm, then adjusted to 1 000–3 000 mPa·s at 25 °C with deionized water. After degassing at −0.095 MPa, the slip is cast on a silicone-coated Mylar carrier at 0.5–2.0 m/min using a doctor blade gap of 150–350 µm. Drying at 60–80 °C for 15–30 min produces green tape that can be punched and screen-printed without edge cracking. Burnout is staged with a hold at 350–400 °C for 2–4 h in flowing air to volatilize the PVA decomposition products before sintering at 1 500–1 600 °C; residual ash content of the grade must be considered when dielectric breakdown strength is specified under IEC 60672-2:1999. The partially hydrolysed structure provides acceptable green strength but can interact with high-surface-area nanosized barium titanate; dispersion stability requires the ammonium polyacrylate adsorption layer to be established before PVA addition, otherwise slurry viscosity drifts over 24 h. Terminal ceramic components manufactured through this binder system include alumina electronic substrates, multilayer ceramic capacitor tapes, and porous ceramic filtration elements.

Compounding B-20TX into High-Humidity Paper Tube Laminating Adhesives

For spiral-wound paper tube production running at 30–80 m/min, CCP B-20TX is a compounding resin in starch/PVA adhesive systems that must develop high green tack without extending set time. A mill formulation combines 20–35 kg CCP B-20TX with 65–80 kg oxidized starch per 1 000 L batch, plus 0.5–1.0 kg sodium hydroxide to adjust pH to 8.0–9.5 and 0.1–0.3 kg defoamer. The vessel is heated to 90–95 °C for 30 min, cooled to 60 °C, and applied by grooved roll to the inner or outer ply at 4–10 g/m² dry adhesive. The PVA fraction increases wet tack within 3–5 s of ply contact, which is necessary when laminating high-bulk recycled liner under speed. Bond strength after 24 h conditioning at 23 °C and 50 % RH exceeds 1.2 N/15 mm in 90° peel mode per ASTM D903-98(2017). In high-humidity board stock above 12 % moisture, the wet bond is more sensitive than starch-only adhesives because the PVA contributes thermoplastic flow but does not eliminate water-induced starch plastication; the adhesive gap must be reduced to 2–4 g/m² to avoid ply slippage.

The terminals are textile yarn carriers, film cores, and protective mailing tubes. The formulation must not be combined with amine-based crosslinkers that are reactive with residual acetate groups under alkaline pH; such combinations accelerate gelation in the hold tank and block transfer lines. Compliance for paper tube adhesives used in indirect food contact packaging is evaluated under FDA 21 CFR 175.105, and export documentation for EU destinations requires REACH registration of the formulated adhesive under Regulation (EC) No 1907/2006. The main operational boundary is pot life: once wetted paste starch is present, microbial activity can reduce viscosity after 24–36 h at 30 °C unless a preservative is added.