Thermoformed Food-Contact Sheet and Migration Control Under EU 10/2011

When PP 1005 is extruded into food-contact sheet for plug-assisted thermoforming, the first control point is not the melt temperature set point but the melt-pressure variation across the die lip, because it determines residual orientation, wall-thickness distribution, and subsequent curl after the tray leaves the female cavity. On production-scale lines, the resin is metered at 92 wt% to 97 wt% of the formulation, with in-house edge trim up to 20 wt% only when the downstream article is not governed by a virgin-material clause or when the reclaim stream has been validated under Commission Regulation (EU) 2022/1616 for recycled plastics intended for food contact. A nucleating agent at 0.05 wt% to 0.20 wt% shortens cycle time by raising crystallization onset temperature, while a phenolic/phosphite antioxidant package at 0.10 wt% to 0.30 wt% and a food-contact-approved colour concentrate at 1 wt% to 3 wt% complete the blend. Compliance is governed by Commission Regulation (EU) No 10/2011, Annex I, with an overall migration limit of 10 mg/dm², and by FDA 21 CFR 177.1520(c) for olefin polymers when export markets require US clearance; migration testing is performed under EN 1186-1:2002 with simulant selection derived from the intended food type. The sheet is produced on a single-screw extruder with a barrier screw of 90 mm to 120 mm diameter and L/D from 30:1 to 34:1, melt temperature 210 °C to 240 °C, screen pack 60/80/100 mesh, and a three-roll polishing stack set at 70 °C to 85 °C for gauges between 0.3 mm and 1.8 mm. The film take-off speed is set to hold the roll gap pressure within a narrow band, and operators record pressure upstream of the screen pack; an increase of more than 2.0 MPa over the start-up value indicates gel accumulation or plate-out, requiring a screen change before film clarity or die lip build-up becomes visible. The sheet is reheated to 155 °C to 170 °C and formed in plug-assisted tools at mould temperatures of 20 °C to 60 °C. Terminal finished articles include single-use dairy portion cups, microwave-ready meal trays, bakery clamshells, and clear or opaque produce punnets. Published data for the specific interaction between PP 1005 and high-fat simulants is limited, so converters must validate overall migration and organoleptic behaviour on the final formed article rather than on pellet feed alone.

The injection moulding of PP 1005 into thick-walled crates and totes is controlled less by part geometry than by the packing-phase pressure window required to avoid sink marks and warpage after demoulding. A typical compound formulation includes 78 wt% to 90 wt% PP 1005, 5 wt% to 12 wt% of an ethylene-octene or EPDM impact modifier, 5 wt% to 15 wt% fine talc for flexural modulus, and 0.2 wt% to 0.5 wt% of a primary/secondary antioxidant system. Material characterisation follows ISO 19069-2:2016 for PP moulding and extrusion materials; test plaques are prepared under ISO 294-1:2017, and tensile, flexural, and Charpy impact values are measured by ISO 527-2:2012, ISO 178:2019, and ISO 179-1:2010 respectively. The machine is selected on clamp force in the range 3500 kN to 7000 kN, with a melt temperature of 220 °C to 250 °C, injection pressure 80 MPa to 120 MPa, holding pressure 50 MPa to 75 MPa, and mould temperature 30 °C to 60 °C. The screw L/D is typically 20:1 to 24:1 with a non-return valve to prevent backflow during the hold phase; backpressure above 1.5 MPa can intensify shear heating and viscosity loss in the barrel. Feed-throat temperature is held at 40 °C to 60 °C to prevent talc bridging, and the shot volume is limited to 40% to 65% of barrel capacity to maintain residence time below 5 min. Terminal products are reusable distribution crates, industrial pallets, tote boxes, and stackable storage containers. Insufficient gate thickness below 2.0 mm to 2.5 mm is a documented cause of jetting and cold slug formation in this processing class.

When Is PP 1005 Suitable for Extrusion Blow Moulding of Small Chemical Containers?

In extrusion blow moulding of PP 1005, the boundary between a sellable chemical container and a rejected parison is set by melt strength and wall-thickness programming, not simply by barrel temperature. When the parison is programmed with 20 to 40 die-gap points to compensate for the low intrinsic melt strength of homopolymer polypropylene relative to HDPE, the process can hold a radial wall-thickness distribution suitable for drop and stack testing. The formulation for non-food chemical bottles is typically 92 wt% to 98 wt% PP 1005, with 1 wt% to 4 wt% UV-stabilised colour masterbatch and 0.1 wt% to 0.3 wt% antioxidant package; high-melt-strength modifiers are avoided unless a specific drop-impact specification must be met, because they can reduce chemical resistance. Regulatory compliance for dangerous-goods packaging is evaluated under the UN Recommendations on the Transport of Dangerous Goods, Chapter 6.1, with the finished container marked with the appropriate UN code such as 3H1 for a plastics jerrican; mechanical performance is verified by stack load and drop testing under the applicable ADR/RID transport regulations. Blow moulding lines use shuttle or accumulator machines with screw diameters between 60 mm and 120 mm, L/D 24:1 to 28:1, melt temperature 190 °C to 220 °C, die swell 20% to 35%, blow air pressure 0.4 MPa to 0.8 MPa, and mould temperature 20 °C to 40 °C. The process window is narrow because parison sag becomes unacceptable when the melt temperature exceeds 220 °C, while brittle pinch-off welds appear when the temperature drops below 190 °C. Containers are often conditioned at −18 °C for 24 h before drop testing to separate brittle failure modes from ductile deformation. Finished product types include 500 mL to 5 L detergent dosing bottles, hydraulic oil containers, agricultural chemical bottles, and industrial solvent reservoirs. PP 1005 is not recommended for containers exceeding 5 L unless a radial wall-thickness uniformity of at least ±0.4 mm can be demonstrated on the specific accumulator head.

The conversion of PP 1005 into automotive interior talc compounds is driven by stiffness and dimensional stability targets rather than by the resin’s initial flexural modulus alone. The compound is built around 60 wt% to 75 wt% PP 1005, 20 wt% to 35 wt% talc, 3 wt% to 8 wt% of an ethylene-octene elastomer, 1 wt% to 3 wt% maleic anhydride-grafted polypropylene as interfacial coupling agent, and a stabiliser package at 0.2 wt% to 0.5 wt%. The talc should have a median particle size D50 of 1.0 µm to 2.0 µm and a top cut below 15 µm to avoid excessive Charpy impact loss. The production line uses a co-rotating twin-screw extruder of 50 mm to 75 mm screw diameter and L/D 40:1, with talc side-fed at L/D 12 to L/D 16 downstream of the main feed to minimise particle attrition, a melt temperature of 180 °C to 220 °C, screw speed 300 min⁻¹ to 500 min⁻¹, and vacuum devolatilisation at a negative pressure of at least 0.08 MPa. Incoming pellet moisture is kept below 0.05 wt% before extrusion to avoid hydrolysis of the coupling agent and surface splay. The pelletised compound is tested for VOC and odour using VDA 278:2016 and VDA 270:2016, and the burning rate of interior components is tested under ISO 3795:1989 at a horizontal burn length of 100 mm or according to the OEM-specific limit. Injection moulding of the compounded pellets follows the same processing discipline, but melt temperature must be capped below 250 °C to prevent odour-generating decomposition of the coupling agent. Terminal finished parts include automotive instrument panel retainers, centre console substrates, door trim lower panels, heater core housings, and appliance base frames.

Raffia Tape Tenacity, Draw Ratio, and Circular Loom Shed Control

Producing raffia tape from PP 1005 on a cast-film line with post-draw slitting places the highest demand on film gauge uniformity, because a thickness variation above ±0.005 mm across the tape width leads to individual tape breaks on circular looms. The formulation for woven sack production is 88 wt% to 95 wt% PP 1005, 2 wt% to 7 wt% ground calcium carbonate, 0.5 wt% to 2 wt% titanium dioxide, 0.2 wt% to 0.6 wt% hindered amine light stabiliser, and 0.1 wt% to 0.3 wt% antioxidant. The cast film is extruded through a flat die with a die gap of 0.6 mm to 1.2 mm at 200 °C to 240 °C, quenched in a water bath of 20 °C to 30 °C and a bath length of 1.5 m to 2.5 m, slit into tapes, stretched in a hot-air oven at 100 °C to 140 °C with a draw ratio of 6:1 to 8:1, and annealed to reduce shrinkage. Mechanical requirements for the slit tape are evaluated according to ASTM D882-18, with elongation at break controlled between 15% and 30%; woven fabric strength is tested under ISO 13934-1:2013 in warp and weft directions. Terminal articles include cement sacks, fertiliser bags, grain sacks, and industrial fibre bundles for flexible intermediate bulk container construction. On modern lines with automatic winders, a draw ratio above 8:1 is usually avoided because it can elevate tape fibrillation and cause flatness inversion during weaving.

For strapping tape converters, the decision to run PP 1005 is determined by crystallisation behaviour in water-bath quenching and the residual orientation achievable in the post-stretching phase. The extrusion formula uses 90 wt% to 96 wt% PP 1005, 1 wt% to 5 wt% calcium carbonate to impart slip and stiffness, 1 wt% to 4 wt% colour masterbatch, and 0.2 wt% to 0.6 wt% UV stabiliser for outdoor storage. The tape is extruded through a flat die at 200 °C to 230 °C, quenched in a water tank at 25 °C to 35 °C, stretched in a hot-air tunnel at 120 °C to 150 °C with a total draw ratio of 6:1 to 8:1, then embossed and wound under controlled tension. Strapping thickness is typically 0.4 mm to 0.8 mm and width 5 mm to 19 mm; embossing depth is held at 30 µm to 60 µm to prevent coil sticking without creating notch sensitivity. Compliance for nonmetallic strapping is assessed under ASTM D3953-15, with breaking strength, retained tension, and loop-joint efficiency reported for the specific strap width; incoming resin melt flow rate is verified by ISO 1133-1:2022 at 230 °C and 2.16 kg. Terminal finished products include nonmetallic strapping for pallet unitisation, light lumber bundling, and carton closure in logistics centres. Published data for the environmental stress-cracking resistance of PP 1005 strapping in long-term outdoor exposure is limited, so UV-stabilised grades are typically validated through accelerated QUV weathering rather than inferred from resin specification alone.