In polyolefin conversion environments where heat and ultraviolet radiation act simultaneously on load-bearing and appearance parts, the grade designated Polycomp CD 10 HS UV3 PP Copolymer is classified as a heat-stabilized polypropylene impact copolymer carrying a UV stabilization package. The model code separates into a CD 10 flow-class marker, an HS heat-stabilization marker, and a UV3 weatherability-stabilization marker. The CD 10 suffix is interpreted as a nominal melt mass-flow rate of 10 g/10 min at 230 °C under 2.16 kg when tested according to ISO 1133-1:2022; the supplier certificate of analysis remains the controlling specification because melt-flow results can vary between laboratories by more than 5 % relative. For impact copolymer polypropylene grades in the 8 g/10 min to 12 g/10 min melt-flow interval, published material datasheets typically report density from 900 kg/m³ to 910 kg/m³ under ISO 1183-1, tensile modulus from 1300 MPa to 1600 MPa under ISO 527-2, notched Charpy impact at 23 °C from 6 kJ/m² to 12 kJ/m² under ISO 179-1/1eA, and heat deflection temperature between 70 °C and 95 °C under ISO 75-2/B. Polycomp CD 10 HS UV3 PP Copolymer is specified for injection molded and extruded components that require a balance of flow, toughness, and surface protection against photodegradation; it is differentiated from non-heat-stabilized impact copolymers by extended oxidative induction time under ISO 11357-6, and from non-UV-stabilized grades by higher retention of gloss and mechanical properties under ISO 4892-2. Published data for this exact grade configuration are limited, so the value ranges above should be treated as property envelopes for the material class rather than batch-specific guarantees.

The 10 g/10 min class sits between the low-flow and high-flow impact copolymer grades, providing lower viscosity than 2 g/10 min material for thin-wall filling while retaining more impact than 25 g/10 min material in moderate-thickness parts. These values are comparative literature envelopes for injection molding material selection; the UV3 and HS packages are superimposed on the flow-class base and do not alter the melt-flow-class position.

Why should the HS and UV3 packages be validated through separate oxidative-induction and xenon-arc protocols?

The heat-stabilization component is commonly assessed by differential scanning calorimetry under ISO 11357-6, where oxidative induction time at 200 °C in oxygen indicates the capacity of hindered phenolic primary antioxidants and organophosphite secondary antioxidants to suppress autocatalytic oxidation. Impact copolymer polypropylene with a conventional HS package often shows oxidative induction time above 20 min at 200 °C, while unstabilized PP copolymer may fall below 5 min under the same test; the exact value for Polycomp CD 10 HS UV3 PP Copolymer is batch-dependent and must be read from the certificate of analysis. The UV3 package is not validated by OIT alone; its function is to absorb ultraviolet radiation and terminate free radicals produced by carbonyl-specific photolysis. Accelerated weathering under ISO 4892-2, cycle 1, using 0.50 W/m² at 340 nm, black standard temperature 65 °C, and 50 % relative humidity, is the standard laboratory method for comparing weatherability. In published data for PP impact copolymer with hindered amine light stabilizer and benzotriazole UV absorber systems, tensile elongation at break retention above 70 % after 1500 h to 2000 h xenon-arc exposure is reported, while unstabilized impact copolymer can lose more than 40 % of elongation before 800 h. Laboratory data are not service-life predictions for every outdoor geometry, because part mass, heat buildup, washing frequency, and oriented skin layers alter real-world weathering. The combined package is process-sensitive: phosphite secondary antioxidants can interact with hindered amine light stabilizers under acidic catalyst residues, and repeated processing above 250 °C may consume the UV3 package before service. Surface yellowing in gas-fired processing environments is often quantified as a change in yellowness index under ASTM E313-20 because phenolic antioxidant by-products can react with trace nitrogen oxides in the melt. On a corotating twin-screw extruder with 40:1 L/D ratio, the stabilizer masterbatch is typically metered through a side feeder after the feed-throat talc addition to shorten high-temperature residence time and preserve the UV3 active fraction.

For thin-wall injection molding where flow-path ratios exceed 200:1, the CD 10 melt-flow class is selected over lower-flow impact copolymers because the melt can be injected at lower holding pressure without exceeding the 250 °C melt-temperature ceiling. On a reciprocating-screw machine with a 25 mm to 40 mm diameter general-purpose screw and 20:1 to 22:1 L/D ratio, starting melt-temperature settings of 200 °C to 240 °C, mold temperatures of 20 °C to 50 °C, and injection pressures between 60 MPa and 100 MPa are representative for impact copolymer polypropylene. Clamp-force requirements on an 80 t to 120 t hydraulic press depend on projected area: as a conservative rule, 4 kN/cm² to 6 kN/cm² of projected area is used for semi-crystalline PP copolymer with wall stock above 1.5 mm. If hot runners are used, manifold and tip temperatures should not exceed 250 °C, and residence time above 230 °C should be kept below 5 min to prevent additive depletion and visible yellowing. Drying is normally not required for unopened material stored below 60 % relative humidity; if surface moisture exceeds 0.05 % under ISO 15512:2019, desiccant drying at 80 °C for 2 h to 3 h is applied. Mold shrinkage for the impact copolymer class is commonly 1.2 % to 1.6 % in the flow direction and 1.0 % to 1.4 % transverse, as measured on 60 mm × 60 mm × 2 mm plaques under ISO 294-4. Because shrinkage is anisotropic, gate location changes can shift warpage by more than 1 mm on a 300 mm span, particularly when the UV3 package modifies crystallization kinetics at the surface.

Incoming inspection and batch-to-batch additive-dose confirmation

Because the UV3 and HS packages are functional chemical systems, melt-flow rate alone is insufficient for incoming inspection. A quality-control protocol typically verifies melt mass-flow rate by ISO 1133-1:2022 at 230 °C/2.16 kg, oxidative induction time by ISO 11357-6 at 200 °C, ash content by ISO 3451-1 if a filler or nucleating package is present, and tensile modulus on standardized specimens by ISO 527-2. For UV-stabilized grades, a weatherability spot check under ISO 4892-2 is lengthier but may be required for first article approval. During long production campaigns, melt-flow drift from 9.5 g/10 min to 11.5 g/10 min can change fill time, part mass, and gate freeze-off; on a 120 t injection machine, a 0.5 g/10 min increase in MFR may shorten fill time by 0.2 s to 0.4 s, which is enough to alter cushion position if the machine does not compensate. Additive dose confirmation is performed by extraction or chromatographic methods on the granulate, not on molded parts, because molding thermal history destroys part of the antioxidant system. A single-screw recycle stream increases stabilizer depletion; repeated regrind use above 30 wt% can reduce oxidative induction time by more than 20 % compared with virgin pellets. Published data for this specific configuration is limited, so internal trials are required before approving regrind at production scale.

In sheet extrusion of the CD 10 HS UV3 grade, a 45 mm single-screw extruder with 30:1 L/D and barrier screw geometry is usually operated with a barrel temperature profile from 180 °C at the feed throat to 220 °C at the die, while melt temperature measured by an immersible thermocouple is held at 230 °C to 240 °C. Chill-roll temperatures are set between 20 °C and 30 °C, and the air gap is minimized to prevent sheet sag and excessive orientation. Because the 10 g/10 min flow class has lower melt strength than 2 g/10 min impact copolymer, deep-draw thermoforming at draw ratios above 2:1 can produce sidewall thinning beyond 15 % when plug-assist speed is too high or sheet temperature is too low. Pre-drying the sheet to 0.05 % moisture or less under ISO 15512:2019 is required when any visible condensation occurs; hydrolysis of phosphite stabilizers can reduce the oxidative induction time and produce surface splay. Grade substitution from a homopolymer PP to the CD 10 impact copolymer requires purging with a low-MFR transition material and resetting the die gap because the die swell and melt extension differ. In extrusion processes, the UV3 package should not be combined with additional amine-based antistatic additives without compatibility testing; amine species can deactivate hindered amine light stabilizers and reduce weatherability. Equipment cleaning with chlorinated solvents is not recommended at melt-contact surfaces because residual solvent can thermally decompose into acidic species that attack the additive package.

Outdoor weathering limits not captured by melt-flow or density data

The UV3 designation indicates that the grade is stabilized for ultraviolet exposure, but the stabilization level should be verified by the expected outdoor stress and not by any single physical property. Under ISO 4892-2, a change in yellowness index of less than 4 units after 1000 h has been used for automotive interior components, while exterior unpainted applications may require a longer test or outdoor exposure under ASTM G7-22 at 45° south-facing direct exposure. The grade-specific weatherability data for Polycomp CD 10 HS UV3 PP Copolymer are not published here; they must be obtained from the supplier. The distinction between UV3 and commodity heat-only grades is most evident at the surface: PP copolymer without a light-stabilization package can form surface microcracks and lose gloss after 500 h to 800 h of xenon-arc exposure, while a hindered amine-stabilized UV3 package is formulated to delay this by radical scavenging in the near-surface layer. However, the UV3 package is not a substitute for carbon black in applications where opacity and ultraviolet screening are required; if the compound does not contain 2.0 wt% to 2.5 wt% carbon black, long-term outdoor color retention is limited by pigment fading rather than polymer cleavage. Conversely, the presence of carbon black can reduce weld-line tensile strength by 10 % to 20 % compared with natural material in the same flow class. Part design should therefore separate weathering specifications from mechanical specifications at knit lines.

If the CD 10 Melt-Flow Class Is Substituted for Low-Flow or High-Flow Impact Copolymers in an Existing Mold

The product occupies a midpoint in the impact copolymer polypropylene flow spectrum. When it replaces a 2 g/10 min impact copolymer, the lower viscosity at 230 °C allows shorter filling time and lower injection pressure, but the trade-off is reduced melt strength and a measurable loss in Charpy or Izod impact. Published comparative data for impact copolymer PP show that the notched Charpy at 23 °C can decrease by 15 % to 25 % when moving from the 2 g/10 min class to the 10 g/10 min class, while the same step improves spiral flow length by more than 20 % under identical injection pressure. When the CD 10 grade replaces a 25 g/10 min impact copolymer, the direction reverses: notched impact improves but mold filling may become marginal for wall sections thinner than 0.8 mm or for flow-path ratios above 300:1. The CD 10 grade is distinguished from polypropylene homopolymer by the presence of an ethylene-propylene rubber phase; this lowers flexural modulus by roughly 200 MPa to 500 MPa compared with a homopolymer of similar melt-flow class, but improves notched impact at 0 °C by a factor often exceeding 3. It is distinguished from random copolymer polypropylene by lower transparency and haze, but higher low-temperature toughness and higher elongation at break. Within the same flow class, a heat-stabilized grade can have oxidative induction time at 200 °C that is 3 to 5 times longer than that of a non-heat-stabilized grade under ISO 11357-6. The UV3 package adds a separate light-stabilization function that is absent from standard heat-stabilized impact copolymers; consequently, product interchange should not be based on melt-flow rate alone.

Regulatory classification of Polycomp CD 10 HS UV3 PP Copolymer depends on the exact additive package and cannot be inferred from the generic material name. The base polypropylene copolymer may be assessed under Commission Regulation (EU) No 10/2011 for plastic food-contact materials and under 21 CFR 177.1520 for olefin polymers when the supplier has issued a written migration compliance statement; the UV3 package may contain low-molecular-weight stabilizers that are subject to specific migration limits and may not be cleared for direct food-contact or medical applications. Electrical and electronic applications require verification against Directive 2011/65/EU as amended, particularly for lead, cadmium, and phthalate restrictions, and REACH SVHC screening under Regulation (EC) No 1907/2006. Chemical resistance should be tested under ISO 175:2010 before the material is used with strong oxidizing acids, chlorinated solvents, or high-temperature hydrocarbon oils; polypropylene copolymers are susceptible to swelling by aromatic and halogenated hydrocarbons above 60 °C. Continuous outdoor service at high ultraviolet dose in hot climates may require additional carbon black or a thicker wall because PP copolymer surfaces can develop localized oxidation even with UV3 stabilization if the accumulated absorbed radiation dose exceeds the stabilizer capacity. The material should be stored away from direct sunlight and at temperatures below 40 °C to prevent premature additive consumption.