On high-cavitation closure lines running 48- to 72-cavity stack moulds, the injection-compression sequence for 28 mm PCO 1881 carbonated soft drink closures in HIVOREX CL9210 uses a barrel profile of 170–220 °C and a hot-runner manifold held at 210–230 °C; fill time is constrained to 0.18–0.32 s so that the melt front does not freeze before the tamper-evident band slit fills. Holding pressure is set at 45–70 MPa hydraulic equivalent, with gate-vestige control requiring decompression of 2–4 mm after plastication. Mould temperature is held at 8–16 °C to pull cycle time to 3.8–6.5 s across 32- to 72-cavity tools. The formulation for this route is 97.5–99.0 wt% CL9210, 0.8–1.5 wt% white TiO₂ masterbatch, 0.03–0.08 wt% calcium stearate acid scavenger, 0.04–0.08 wt% primary antioxidant, and 0.04–0.10 wt% secondary antioxidant. Erucamide slip is limited to 0.05–0.10 wt% only when closure torque control is required; omission is preferred for oxygen-sensitive beverages because erucamide migration can alter organoleptic panel scores. Food-contact status rests on FDA 21 CFR 177.1520(c), EU Regulation (EU) No 10/2011 with an overall migration limit of 10 mg/dm² under the assigned food simulant, and GB 4806.7-2016. Terminal products include 28 mm PCO 1881 CSD closures, 30/25 mm bottled water closures, and 38 mm aseptic beverage caps with tamper-evident bands. Barrel residence time above 8 min at 230 °C degrades the slip additive and increases acetaldehyde generation, so purge intervals are fixed at 20–30 cycles after any line interruption. The grade is not suitable for continuous hot-fill above 60 °C because cap dome deflection under top load exceeds seal loss thresholds; stress-crack resistance in aggressive surfactant-containing beverages should be validated per ASTM D1693, condition B, before commercialisation.

What governs wall-thickness consistency in 0.45 mm injection-moulded dairy tubs?

In a 0.45 mm sidewall, wall-thickness consistency in CL9210 dairy tubs is governed by gate melt pressure rather than by barrel temperature alone; at a flow-length-to-wall-thickness ratio above 350:1, injection speed below 300 mm/s produces freeze-off at the sidewall-to-base radius and visible flow lines. The process window is 200–230 °C barrel temperature, 12–20 °C mould temperature, 350–600 mm/s injection speed, and transfer to holding at 95–98% volumetric fill. Holding pressure is 35–60 MPa, applied for 0.6–1.2 s for a 0.30–0.70 mm nominal wall. A 24:1 to 26:1 L/D screw with a compression ratio of 2.5:1 and a check ring free-flow gap of 0.10–0.15 mm prevents shot-to-shot variation above 0.8%. Formulation is 96.0–98.5 wt% CL9210, 1.0–3.0 wt% white masterbatch, 0.05–0.15 wt% synthetic silica antiblock, 0.05–0.12 wt% erucamide slip, and 0.02–0.04 wt% fluoroelastomer processing aid only when filling 0.30–0.40 mm sidewalls yields short-shot rates above 0.5%. Linear mould shrinkage is 1.5–2.0% tested per ISO 294-4, requiring lid diameters to be compensated by 0.4–0.8 mm at the seal perimeter. Compliance for dairy and deli contact follows EU Regulation (EU) No 10/2011, FDA 21 CFR 177.1520, and GB 4806.7-2016; migration testing should be performed in 3% acetic acid and 10% ethanol simulants under 40 °C/10 days for refrigerated distribution. Terminal products are 250–1000 mL dairy tubs, 105–125 mm over lids, and deli containers with peelable film land areas. At wall thickness below 0.30 mm, the required melt pressure can exceed 140 MPa on standard thin-wall machines; a higher-flow grade is required.

The following matrix consolidates the mandatory compliance designations referenced across the downstream injection moulding routes.

Application route	Standard/regulation	Test condition or threshold
Carbonated soft drink and water closures	FDA 21 CFR 177.1520(c); EU Regulation (EU) No 10/2011; GB 4806.7-2016	Overall migration 10 mg/dm²; organoleptic panel score per ASTM E1870
Thin-wall dairy and deli containers	FDA 21 CFR 177.1520; EU Regulation (EU) No 10/2011; GB 4806.7-2016	Migration in 3% acetic acid and 10% ethanol at 40 °C/10 days
UN-certified industrial pails and lids	UN Model Regulations Chapter 6.1; ADR/RID/IMDG; FDA 21 CFR 177.1520	Drop height 1.2 m PG II / 0.8 m PG III at -18 °C
Aerosol overcaps and cosmetic/pharma closures	REACH Regulation (EC) No 1907/2006; USP <661.1>; EU Regulation (EC) No 1223/2009	SVHC declaration under Article 33; pharmacopeial plastic component testing
Dispensing hinge closures	FDA 21 CFR 177.1520; EU Regulation (EU) No 10/2011; REACH Regulation (EC) No 1907/2006	Hinge flexural fatigue 1,000 cycles at 23 °C and 5 °C
Edible oil and sauce closures	FDA 21 CFR 177.1520(c); EU Regulation (EU) No 10/2011; GB 4806.7-2016	ESCR ASTM D1693 condition B; organoleptics per ASTM E1870

At a pail lid outer diameter of 300 mm and nominal wall thickness of 2.8 mm, holding pressure must be maintained until the sprue gate freezes at 8–12 s; premature hold release produces ring-shaped sink marks around the gate and radial warpage above 1.5 mm across the lid. Injection moulding of UN-certified open-head pails and lids in CL9210 runs on clamp force 10000–16000 kN, with melt temperature 190–230 °C, mould temperature 10–25 °C, injection pressure 80–120 MPa, holding time 12–25 s, and total cycle 35–60 s for 5–25 L bodies. The formulation for industrial and food-ingredient pails is 97.5–99.0 wt% CL9210, 1.0–2.5 wt% colour masterbatch, 0.06–0.12 wt% antioxidant package, and 0.10–0.25 wt% hindered amine light stabiliser when outdoor warehouse storage forms part of the supply chain. UN compliance for dangerous goods packaging is established under UN Model Regulations Chapter 6.1, with drop heights of 1.2 m for packaging group II and 0.8 m for packaging group III at -18 °C; food contact pails require FDA 21 CFR 177.1520 and EU Regulation (EU) No 10/2011 where the pail directly contacts dry or aqueous food ingredients. Terminal products include 5 L, 10 L, 20 L, 25 L open-head pails and lids with gasket seats, tamper-evident tear tabs, and pour spouts. CL9210 should not be specified for concentrated oxidising acids or solvents classified under packaging group I above 60 °C; environmental stress crack resistance in wetting-agent solutions must be pre-qualified per ASTM D1693, condition A, for each lid geometry.

Aerosol Overcap Skirt Cracking as a Function of Mould Temperature and Ejection Angle

Skirt cracking at the lower edge of 45 mm, 52 mm, and 65 mm aerosol overcaps in CL9210 is primarily controlled by ejection temperature, undercut release angle, and mould cooling uniformity. The process window is 190–215 °C melt temperature, 15–30 °C mould temperature, 300–500 mm/s injection speed, and holding pressure 40–65 MPa for wall thickness between 0.65 mm and 1.2 mm. Forced ejection without mechanical slides requires a stripper plate travel synchronized to 10–15 mm of core withdrawal and a minimum draft angle of 1.0° on the skirt interior; lower draft angles increase white stress marking and fracture rate above 2% at the lower skirt edge. Formulation is 98.0–99.5 wt% CL9210, 0.5–2.0 wt% colour masterbatch, 0.05–0.20 wt% zinc stearate lubricant, and 0.05–0.10 wt% slip additive for snap-fit assembly. Antistatic additive in the range 0.05–0.15 wt% is used only when dust attraction in warehouse filling lines is a documented defect; higher loadings reduce surface resistivity but can reduce hinge impact resistance. Cosmetic and pharmaceutical secondary packaging compliance is governed by REACH Regulation (EC) No 1907/2006, USP <661.1> for plastic packaging components where the closure is supplied to pharmacopeial customers, and EU Regulation (EC) No 1223/2009 for packaging of cosmetic formulations. The terminal products are 45 mm, 52 mm, and 65 mm aerosol overcaps, lotion pump collars, pharmaceutical snap caps, and fragrance cap bases. Mould temperatures below 10 °C are incompatible with forced ejection of CL9210 overcaps; skirt cracking increases sharply due to reduced elongation at the ejection temperature.

When Dispensing Closure Hinge Life Dictates Melt Temperature

After the hinge central web freezes within 0.15–0.30 s, the processor must transfer from velocity control to holding pressure at 95–100% volumetric fill to preserve chain orientation across the hinge; a delayed transfer produces a frozen layer at the hinge root and reduces flexural endurance by more than 30%. Living-hinge dispensing closures moulded in CL9210 use a barrel temperature of 190–220 °C, mould temperature of 18–30 °C, injection speed of 400–650 mm/s, holding pressure of 30–50 MPa, and holding time of 1.0–2.5 s for hinge thickness of 0.20–0.35 mm across a 2–6 mm hinge width. The formulation is 97.0–99.0 wt% CL9210, 0.4–1.8 wt% colour masterbatch, 0.05–0.12 wt% antioxidant, 0.05–0.15 wt% slip, and 0.02–0.06 wt% nucleating agent only if cycle time reduction below 10 s is required. Hinge endurance is validated by 1,000 open/close cycles at 23 °C and 5 °C; hinge root radius below 0.20 mm initiates stress whitening and eventual cracking. Food-contact dispensing closures must comply with FDA 21 CFR 177.1520 and EU Regulation (EU) No 10/2011; cosmetic closures require REACH Regulation (EC) No 1907/2006. Terminal products include flip-top caps for shampoos, conditioners, condiments, and 28 mm beverage dispensing closures with tamper-evident features. The formulation must not contain amine-based additives if post-mould printing with certain ink systems is planned; amine blooming interferes with ink adhesion.Because unsaturated oil permeation into the amorphous tie-chain regions lowers environmental stress crack resistance, edible oil closures in CL9210 are moulded with a minimum corner radius of 0.25 mm at the thread root and a tamper-evident band slit that avoids sharp internal notches. The process for 29/25 mm edible oil bottle closures uses melt temperature 195–225 °C, mould temperature 10–18 °C, injection speed 250–450 mm/s, and cycle time 5–9 s on 32-cavity unscrewing tools. Formulation is 98.0–99.5 wt% CL9210, 0.5–1.5 wt% colour masterbatch, 0.04–0.10 wt% antioxidant, 0.05–0.12 wt% slip, and 0.02–0.06 wt% acid scavenger. Food-contact compliance is established under FDA 21 CFR 177.1520(c), EU Regulation (EU) No 10/2011 with fatty-food simulant D2 or 95% ethanol, and GB 4806.7-2016. Terminal products include 29/25 mm edible oil bottle closures, 31.5 mm screw caps for sauces, and dispensing fitments for condiments. Stress-crack resistance should be validated per ASTM D1693, condition B, with no failure before 48 h in 10% Igepal at 50 °C; organoleptic neutrality is confirmed by ASTM E1870 sensory panel testing before specification.