| HS Code | 883402 |
| Density | 0.90 g/cm³ |
| Melt Flow Rate | 4 g/10min at 230°C/2.16kg |
| Tensile Strength At Yield | 35 MPa |
| Elongation At Yield | 12% |
| Flexural Modulus | 1600 MPa |
| Izod Impact Strength Notched 23 C | 3.5 kJ/m² |
| Heat Deflection Temperature 0 45 Mpa | 110°C |
| Vicat Softening Temperature | 155°C |
| Melting Point | 165°C |
| Rockwell Hardness | R95 |
As an accredited MTEGRITY PP Homopolymer PP400 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | MTEGRITY PP Homopolymer PP400 is supplied in 25 kg sealed polyethylene-lined bags, palletized and shrink-wrapped for safe transport. |
| Container Loading (20′ FCL) | 20′ FCL loaded with MTEGRITY PP Homopolymer PP400, packed in 25kg bags on pallets, shrink-wrapped, secured for safe transport. |
| Shipping | MTEGRITY PP Homopolymer PP400 is a thermoplastic resin supplied as free-flowing pellets. Ship in clean, dry containers or lined railcars/trucks to prevent contamination and moisture pickup. Store away from heat, ignition sources, and direct sunlight. Not classified as hazardous; ensure adequate ventilation and safe handling during transport. |
| Storage | Store MTEGRITY PP Homopolymer PP400 in a cool, dry, well-ventilated area away from direct sunlight, heat, and ignition sources. Keep containers tightly sealed to prevent moisture and contamination. Avoid exposure to strong oxidizers. Protect bags from damage and stacking hazards. Handle with care to minimize dust generation. No special temperature control required, but maintain stable conditions. |
| Shelf Life | Shelf life for MTEGRITY PP Homopolymer PP400 is typically 12 months from manufacture when stored unopened in cool, dry conditions. |
In thin-wall injection moulding of dairy cups and lids from PP400 homopolymer, the processing boundary is defined less by melt temperature setpoint than by the interaction between melt flow length, gate diameter, and hold-pressure decay. In a cold-runner mould with nominal wall thickness of 0.45 mm to 0.70 mm, the flow-length-to-wall-thickness ratio frequently exceeds 200:1; fill analysis therefore relies on grade-specific melt flow rate measured according to ISO 1133-1:2022 at 230 °C and 2.16 kg rather than a generic polypropylene viscosity curve. Injection velocities of 200 mm/s to 450 mm/s are common on hydraulic and all-electric machines, but limiting pressure decay is controlled by gate freeze time rather than screw recovery. If the gate diameter is below 0.8 mm, hold pressure must transfer before gate solidification; otherwise sink marks and post-mould warpage appear. Clamp force on production machines typically ranges from 150 t to 350 t for multicavity dairy cup moulds, although the required force is calculated from projected area and cavity pressure in the range of 35 MPa to 60 MPa. The melt temperature at the nozzle is generally set at 230 °C to 250 °C, with the upper boundary governed by the onset of thermo-oxidative degradation above 260 °C and the lower boundary by short-shot risk below 210 °C. Mould temperature is maintained at 15 °C to 35 °C for rapid skin formation, although higher mould temperatures up to 50 °C are applied where gloss replication is required. Drying is not a bulk requirement because PP homopolymer absorbs less than 0.01 % moisture at 23 °C and 50 % RH, but surface condensation from cold storage should be removed by a hopper dryer at 70 °C to 80 °C for 1 h to 2 h when relative humidity exceeds 60 %. Copper-containing masterbatches and copper-based heat stabilizers are to be avoided unless the full stabilizer package is validated, because copper ions accelerate chain scission in polypropylene at elevated processing temperatures. Food-contact compliance for thin-wall dairy packaging is governed by FDA 21 CFR 177.1520(c) 1.1a in the United States and by Commission Regulation (EU) No 10/2011 in the European Union, with the overall migration limit set at 10 mg/dm² under migration test methods in the EN 1186 series. Pigment and antistatic masterbatches are incorporated at 2 wt% to 4 wt%, provided each additive conforms to the applicable positive list or end-test condition for the intended food type. End products include thin-wall drinking cups, dairy yogurt pots, and snap-on lids, where PP400 homopolymer forms a dense oriented skin at the mould surface while melt continues to flow through the frozen-layer core.
| Jurisdiction | Reference | Test method | Numerical criterion |
|---|---|---|---|
| United States | FDA 21 CFR 177.1520(c) 1.1a | End-test extraction per FDA 21 CFR 177.1520(d) | Specified maxima for n-hexane and xylene extractives |
| European Union | Commission Regulation (EU) No 10/2011 | EN 1186-1 to EN 1186-15 | Overall migration <10 mg/dm² |
| China | GB 9685-2016 | GB 31604.1 | Additive positive list and specific migration limits |
Because biaxially oriented polypropylene film lines using PP400 homopolymer require a cast or tubular quench step before orientation, the first process variable is not the orienter speed but the chill-roll temperature. Cast sheet is quenched on a chill roll at 15 °C to 30 °C to suppress spherulite growth; a cast sheet density above 0.89 g/cm³ under ISO 1183-1:2019 indicates excessive crystallinity and produces film with insufficient transverse stretch. The sheet is then conditioned at 130 °C to 150 °C before machine-direction stretching. Machine-direction orientation ratios are commonly set between 4.5:1 and 6.0:1, while transverse-direction ratios on the tenter frame range from 8.0:1 to 10.0:1. Total area orientation ratios above 60:1 may cause web breaks in homopolymer PP if incoming cast-sheet thickness defects or gauge bands are present. MD draw temperature and TD preheat temperature are selected from melting onset measured by ISO 11357-3:2018 differential scanning calorimetry, not from the nominal PP melting point. Film gauge uniformity across the die is controlled by melt temperature profile and die geometry, with melt temperature at the die exit generally held from 240 °C to 260 °C. A die gap of 2 mm to 3 mm is common for subsequent orientation; wider die gaps reduce orientation precision and can thicken edge beads. Slip and antiblock masterbatches are dosed at 0.05 wt% to 0.25 wt% of each active component, depending on film gauge and converting speed. Corona treatment is applied at 38 mN/m to 42 mN/m surface energy for lamination or metallization; high-energy corona above this range can embrittle the film surface and reduce seal strength. Oriented film properties are tested under ASTM D882-18 for tensile modulus and elongation at break in MD and TD, under ASTM D2457-21 for gloss, and under ASTM D1709-16a for dart impact. Food-contact BOPP produced from PP400 must comply with FDA 21 CFR 177.1520 and Commission Regulation (EU) No 10/2011 at the finished film level. End uses include snack-food overwrap, confectionery bundling, tape backing, and metallized barrier film where the base layer is PP400 homopolymer. One limitation in BOPP converting is that PP400 is a homopolymer with a relatively sharp melting range; seal initiation temperature is therefore set above 145 °C and confirmed by ASTM F88/F88M-21 heat-seal strength measurement on the finished laminate.
Initially, raffia tape production from PP400 homopolymer is carried out on a single-screw extruder operating at a melt temperature of 220 °C to 250 °C and a die gap of 0.8 mm to 1.2 mm. The flat tape is quenched in a water bath at 25 °C to 40 °C; water temperature above 45 °C delays skin solidification and produces draw resonance or tape width variation. The quenched sheet is slit and then stretched in a hot-air oven at 120 °C to 150 °C using a draw ratio between 6:1 and 9:1. Drawing below 5:1 leaves excessive elongation at break, while drawing above 9:1 can produce fibrillation or uncontrolled splitting in tape weaving. Pigment masterbatch is metered at 1 wt% to 3 wt% for woven-sack colour fastness, and UV stabilizer masterbatch at 1 wt% to 2 wt% is required for sacks exposed to sunlight; stabilizer loading is validated by accelerated weathering per ISO 4892-2:2013 and retained tensile strength after exposure. Tape tensile properties are checked on the drawn tape using ISO 527-3:2018 or ASTM D882-18; a drawn tape from PP400 homopolymer exhibits a distinct yield point and a draw-ratio-dependent modulus increase. The woven fabric is produced on circular looms where tape stiffness affects shed formation; excessive tape elongation above 14 % at 5 N tension can cause loom stops and fabric defects. End products are woven sacks, bulk bags, and geotextile tapes, most of which are non-food industrial packaging unless an inner liner supplies the food-contact surface. For food-contact bulk packaging, the woven structure itself is usually outside the food-contact layer; any inner liner must meet FDA 21 CFR 177.1520 or Commission Regulation (EU) No 10/2011.
For thermoforming of PP400 homopolymer sheet, flat-die extrusion is run at 220 °C to 240 °C, followed by polished roll-stack cooling. The formed sheet is heated to a surface temperature of 150 °C to 170 °C before forming; below 150 °C, the sheet develops excessive corner thinning, and above 170 °C, sag limits draw depth. Vacuum forming is used for shallow trays and pressure forming for deep-draw cups with draw ratios up to 3:1. Because PP400 is a homopolymer, melt strength is lower than block copolymers, so plug assist is generally required for draw ratios above 1.5:1 to avoid non-uniform wall thickness. Sheet stock is tested for sag resistance under ISO 75-2:2013 heat deflection temperature and for tensile yield under ISO 527-2:2012. Food-contact trays and cups produced from PP400 homopolymer fall under FDA 21 CFR 177.1520 and Commission Regulation (EU) No 10/2011.
Compounding PP400 homopolymer with talc and elastomer is performed on a corotating twin-screw extruder with L/D ratio of 40:1 to 52:1, where PP400 is fed in the main hopper and talc is side-stuffed downstream after the PP has melted to limit screw wear and preserve talc platelet morphology. Talc loading is commonly set at 10 wt% to 25 wt%; loadings above 30 wt% reduce weld-line strength and require elastomer modification to restore impact. Ethylene-propylene rubber or polyolefin elastomer is added at 5 wt% to 15 wt% for interior impact requirements; the actual ratio is tuned to meet notched impact values measured by ISO 179-1:2010 at 23 °C and -20 °C. Typical compound targets for an automotive interior substrate include flexural modulus of 1,800 MPa to 2,800 MPa under ISO 178:2019, tensile yield stress above 20 MPa under ISO 527-2:2012, and heat deflection temperature above 65 °C under ISO 75-2:2013 Method A at 1.80 MPa. These values are indicative of talc-filled homopolymer PP compounds, not a specification for PP400 alone; published data for PP400-specific talc compounds is limited, so the converter must generate a compound-specific data set because PP400 molecular weight and stabilizer package determine the final impact drop after filler addition. Twin-screw screw speed is typically set from 300 min⁻¹ to 600 min⁻¹, with specific mechanical energy input of 0.18 kWh/kg to 0.28 kWh/kg. The melt temperature discharged from the extruder is held below 230 °C to limit oxidative degradation, and a vacuum vent at -0.08 MPa removes volatiles. Antioxidant masterbatch is dosed at 0.3 wt% to 0.6 wt% and is selected for long-term heat aging performance under ISO 188:2023 at 150 °C or per OEM specification. For automotive interior applications, the finished compound must pass volatile organic compound limits using VDA 278:2018 and fogging limits using DIN 75201:2011; PP400 homopolymer must therefore be selected with a low oligomer content and the converter should request a certificate of analysis covering extractables. Shrinkage is evaluated under ISO 294-4:2018; talc reduces machine-direction and transverse-direction shrinkage anisotropy compared with unfilled PP. REACH compliance applies to the finished compound placed on the EU market, and RoHS Directive 2011/65/EU applies if the part carries electrical or electronic content. End products include injection-moulded door panel carriers, A/B-pillar lower trim, and seat side shields, where the PP400 compound is moulded at 220 °C to 240 °C and mould temperature of 30 °C to 50 °C.
Across spunbond nonwoven lines, PP400 homopolymer processing is sensitive to melt-temperature uniformity across the spin beam because filament velocity and quench-air temperature define fibre diameter and fabric tensile strength. The extruder is a single-screw machine with L/D ratio of 30:1 to 36:1, and melt temperature at the spin beam is maintained at 230 °C to 250 °C. Melt filtration is mandatory; a screen changer with filtration size of 40 μm to 80 μm removes gel particles and unmelts that otherwise block spin holes. Spin-hole throughput is typically 0.4 g/hole/min to 0.8 g/hole/min, depending on target denier; the filaments are drawn pneumatically at velocities that may exceed 3,000 m/min. Quench air at 8 °C to 16 °C with high uniformity is used to prevent roping and to stabilise filament diameter; quench-air velocities above 1.5 m/s can cause fibre vibration and denier variation. The resulting webs are bonded by calendering at roll temperatures of 140 °C to 160 °C and line pressure of 60 N/mm to 100 N/mm. Fabric tensile strength and elongation are tested by ISO 9073-3:2023, and hydrostatic head requirements for hygiene or medical fabrics are tested by ISO 811:2018. PP400 homopolymer can be used at 100 wt% without masterbatch for general technical nonwovens; for coloured or UV-stabilized fabrics, masterbatch is dosed at 1 wt% to 3 wt% and must be selected for melt-filtration compatibility. Because PP400 is a homopolymer, spunbond fabrics produced from it exhibit lower transverse tear resistance than fabrics made from impact or random copolymer PP; fabric grammage and bonding pattern must therefore be developed on the specific spunbond line rather than transferred from a copolymer formulation. End products include hygiene top-sheet support layers, filtration support layers, geotextiles, and furniture backing. For hygiene and medical nonwovens, skin-contact safety requirements are governed by ISO 10993-1 where medical device claims are made and by REACH for chemical safety.
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In the homopolymer polypropylene segment, MTEGRITY PP Homopolymer PP400 is a general-purpose injection-molding resin supplied for thin-wall packaging, caps and closures, appliance interiors, and structural houseware components. The grade designation PP400 identifies a polypropylene homopolymer with a controlled melt flow range and stabilizer package; lot-specific values shall be taken from the supplier certificate of analysis before tooling or process qualification. The processing and property ranges cited in this technical overview are representative of unfilled PP-H injection-molding grades and are not a substitute for grade-specific data. Where no PP400-specific published figure is available, the text identifies the limitation explicitly and gives the relevant method under ISO, ASTM, or regulatory reference frameworks.
In comparison with random copolymer grades, a homopolymer such as PP400 contains no ethylene comonomer in the main propylene backbone. This absence produces higher crystalline order, higher stiffness, higher tensile yield strength, and lower impact resistance at subambient temperature. Published data for comparable unfilled grades show tensile yield strength ranges of 30–38 MPa for PP-H under ISO 527-2, while random copolymers often fall between 24 MPa and 32 MPa. Conversely, impact copolymer grades contain a dispersed ethylene–propylene rubber phase and show notched Charpy impact values above 10 kJ/m² at 23 °C, whereas homopolymer PP400-class resins typically register 2–5 kJ/m² under ISO 179-1/1eA. This trade-off is the primary selection boundary for applications requiring low-temperature drop resistance rather than stiffness.
Measured on injection-molded specimens conditioned at 23 °C and 50 % relative humidity, unfilled PP-H of the PP400 class generally exhibits a density of 0.900–0.910 g/cm³ under ISO 1183-1 and a flexural modulus between 1,200 MPa and 1,800 MPa under ISO 178. Heat deflection temperature under ISO 75-2/B at 0.45 MPa commonly lies in the 90–105 °C band, while the melting peak temperature recorded by differential scanning calorimetry under ISO 11357-3 is typically 160–170 °C for polypropylene homopolymer. These values do not establish a specification for PP400; they are provided as the technical envelope against which a certificate of analysis should be compared.
| Property | Test method | PP-H (PP400 class) | PP random copolymer | PP impact copolymer |
|---|---|---|---|---|
| Density | ISO 1183-1 | 0.900–0.910 g/cm³ | 0.890–0.900 g/cm³ | 0.900–0.910 g/cm³ |
| Melt mass-flow rate at 230 °C/2.16 kg | ISO 1133-1 | 12–25 g/10 min | 8–25 g/10 min | 4–25 g/10 min |
| Tensile yield strength | ISO 527-2 | 30–38 MPa | 24–32 MPa | 22–30 MPa |
| Tensile modulus | ISO 527-2 | 1,300–1,800 MPa | 800–1,200 MPa | 900–1,400 MPa |
| Flexural modulus | ISO 178 | 1,200–1,800 MPa | 700–1,100 MPa | 900–1,500 MPa |
| Notched Charpy impact at 23 °C | ISO 179-1/1eA | 2–5 kJ/m² | 5–12 kJ/m² | 10–40 kJ/m² |
| Heat deflection temperature B | ISO 75-2/B | 90–105 °C | 75–95 °C | 85–100 °C |
Differences between PP400 and nucleated high-crystallinity grades should also be considered. Nucleated homopolymer grades may raise heat deflection temperature by up to 10 °C and reduce mold shrinkage by lowering spherulite size, but they can also increase brittleness and require tighter melt temperature control during startup. Published data for this specific comparison is limited; therefore, the comparative data in the table are restricted to general unfilled PP-H, random copolymer, and impact copolymer classes.
On a conventional hydraulic or electric injection molding machine with a general-purpose polyolefin screw of 20:1 to 25:1 L/D and compression ratio of 2.5:1 to 3.5:1, PP400-class material is processed with a melt temperature set point between 220 °C and 260 °C. The mold surface temperature should be held between 20 °C and 60 °C; higher mold temperatures reduce orientation and improve gloss but extend cycle time. If the resin has been exposed to relative humidity above 60 %, pre-drying at 80 °C for 2 h is advisable to prevent surface splay, although polypropylene homopolymer does not ordinarily require desiccant drying.
First-stage injection pressure is typically 70–120 MPa on the material, with a hold pressure of 50–80 % of the injection pressure selected to control sink marks. Back pressure between 0.5 MPa and 2.0 MPa and screw surface speed of 30–80 m/min are common starting points; excessive back pressure or residence time above 280 °C can cause chain scission and shift the melt flow rate beyond the lot specification. A shut-off nozzle or valve gate is preferred for low-viscosity PP400-class melts to prevent drooling and to maintain a stable cushion of 3–6 mm.
High-flow PP-H grades of this class are normally specified by melt mass-flow rate under ISO 1133-1 at 230 °C and 2.16 kg load. If the PP400 lot certificate shows a melt flow rate in the 12–25 g/10 min band, the material is suitable for thin-wall molding where flow length-to-wall-thickness ratios of 150:1 to 250:1 are common in spiral-flow evaluations under ASTM D3123. Lower melt flow rate lots should be selected for thick sections or injection blow molding, where too high a melt flow rate may produce excessive flash and poor impact. Published data for PP400-specific spiral flow curves is limited, so gate-freeze time and minimum packing pressure should be determined on the target mold.
Molecular weight distribution is an important variable in PP400 conversion. Controlled-rheology homopolymer grades are obtained by peroxide-induced chain scission during compounding, narrowing the molecular weight distribution and reducing die swell and melt extensional memory. This improves injection speed and reduces warpage, but narrows the processing temperature window. In production-scale single-screw machines with 25 mm to 80 mm screw diameter, melt temperature measured at the nozzle should be checked with an insertion probe against the set point; a deviation greater than 5 °C from barrel to nozzle often indicates shear heating or poor hold pressure control.
Rheologically, unfilled PP-H exhibits shear thinning above 100 s⁻¹; capillary viscosity at 230 °C and 1,000 s⁻¹ is typically in the 50–150 Pa·s range for medium-flow grades. At a hot runner gate shear rate of 10⁴–10⁵ s⁻¹, melt temperature may rise locally by 10–25 °C depending on gate diameter. Processing PP400 therefore requires balancing fill speed against shear heating; if the gate temperature exceeds 260 °C, thermal degradation can produce an acidic odor and yellowing. Published data for PP400-specific shear viscosity is limited; the values are characteristic of PP-H with comparable melt flow.
Unfilled polypropylene homopolymer undergoes volume contraction during crystallization. Mold shrinkage measured according to ISO 294-4 is generally 1.0–2.0 % for PP-H, with lower shrinkage in the flow direction and higher shrinkage in the transverse direction. Because PP400 contains no impact modifier or filler, anisotropic shrinkage is governed mainly by gate location, flow orientation, and mold temperature. To reduce differential shrinkage, the mold should be cooled uniformly within 5 °C across the cavity surface. Holding pressure must be maintained until the gate freezes; otherwise sink marks and internal voids occur at thick bosses and ribs.
Post-mold dimensional changes continue for up to 48 h at ambient temperature. Annealing at 80–100 °C for 1–2 h accelerates relaxation and stabilizes critical dimensions before assembly. This is particularly relevant for appliance panels and pump dispenser assemblies where warpage beyond 0.5 mm on a 200 mm span can cause functional interference.
Addition of a nucleating agent at 0.05–0.25 wt% can increase crystallization temperature and reduce cycle time by 5–15 %, but it may reduce notched impact strength and change shrinkage. Color concentrates should be selected with a carrier resin compatible with PP-H; polyethylene-based masterbatch carriers can reduce tensile yield strength and should be limited to 2–4 wt% unless validated by ISO 527-2 testing.
Polypropylene homopolymer grades typically fall under FDA 21 CFR 177.1520 for olefin polymers in food-contact applications when the final polymer meets the specified density, extraction, and solubility limits. For the European Union, food-contact compliance is assessed under EU Regulation 10/2011, and the overall migration limit for plastic food-contact articles is 10 mg/dm². However, PP400-specific compliance must be confirmed from the supplier’s regulatory certificate; the presence of processing aids, antioxidants, or nucleating agents may require additional specific migration testing. No medical-grade claim is made unless the lot is supported by the appropriate pharmacopoeial or ISO 10993 documentation.
Electrical applications such as coil bobbins or connector housings may require insulation resistance and comparative tracking index data. Unfilled PP-H typically has a comparative tracking index above 600 V under IEC 60112, but the exact value is formulation-dependent. For outdoor electrical use, ultraviolet stabilization is necessary because neat PP-H will embrittle when exposed to UV-A radiation.
| Requirement | Reference | Typical status for unfilled PP-H |
|---|---|---|
| Food-contact use in the United States | FDA 21 CFR 177.1520 | Complies when polymer meets olefin monograph conditions and end-use limitations |
| Plastic food-contact materials in the EU | EU Regulation 10/2011 | Subject to overall migration limit of 10 mg/dm²; specific migration of additives must be verified |
| Restriction of hazardous substances | RoHS Directive 2011/65/EU | Typically not restricted for unfilled PP-H; confirm batch |
| Registration, evaluation, authorisation and restriction of chemicals | REACH Regulation (EC) No 1907/2006 | Polymer is exempt from registration; monomers and additives require registered status |
The substitution of PP400 for filled polypropylene should be evaluated through stiffness, shrinkage, and impact data. Talc-filled PP-H at 20 wt% filler commonly shows a flexural modulus of 2,500–4,000 MPa, while 30 wt% glass-filled PP-H commonly falls between 5,000 MPa and 7,000 MPa under ISO 178. PP400, as an unfilled grade, is at the lower end of the stiffness spectrum and should not be selected for structural brackets originally designed in filled systems without a complete structural analysis. However, the absence of mineral filler gives PP400 lower density, smoother surfaces, lower screw and barrel wear, and better colorability.
Under sustained load, unfilled polypropylene exhibits creep and stress relaxation at room temperature. At 20 MPa tensile stress and 23 °C, PP-H has significantly higher creep strain than talc-filled or glass-filled grades. Published data for PP400-specific creep modulus is limited; the design engineer should instead obtain flexural creep or tensile creep curves under ISO 899-2 or ISO 899-1 before using PP400 in snap-fit or threaded closures where continuous stress is applied.
For PP400, hot runner and gating systems should be designed with the low melt viscosity in mind. Needle valve gating is preferred over open edge gates because it produces positive shut-off and controls drool. Gate diameter should be 30–50 % of the wall thickness for unfilled PP-H, but shear heating must be checked by measuring melt temperature after the hot runner. If the measured hot runner melt temperature exceeds 260 °C, reduce runner temperature or increase gate diameter.
Pressure drop across the hot runner should not exceed 40 MPa; higher values may reduce the effective hold pressure at the gate and create sink marks. In multi-cavity molds, balanced runner lengths are required to maintain cavity-to-cavity weight variation below 0.5 %.
On the molding floor, startup with PP400 should be preceded by purging with a clean polypropylene purge grade, not with PVC or ABS, because residual chlorinated polymer can cause acidic gas and corrosion. If the previous material was an engineering resin with high processing temperature, the barrel should be purged at 240 °C and the screw checked for deposits. Production lots should be monitored for melt flow shift; a variation of more than 20 % from the certificate value may indicate contamination, moisture, or excessive residence time.
The stabilizer system in PP400 is designed for short-term thermal protection during injection molding and for moderate end-use oxidative stability. Reprocessing of regrind is common at 10–30 wt%, but each heat history shifts the melt flow rate upward and reduces tensile elongation at break. Under ISO 1133-1, repeated extrusion through a single-screw machine at 240 °C may increase the melt flow rate by 5–15 % per cycle for lightly stabilized PP-H; PP400-specific data should be requested from the supplier if more than three regrind cycles are planned. Long-term heat aging resistance is evaluated by oven aging at 135 °C or 150 °C with tensile elongation retained after 500–1,000 h under ISO 527-2 observed as a common benchmark. Published data for PP400-specific aging curves is limited and must not be interpolated from other grades.
Quality assurance for MTEGRITY PP Homopolymer PP400 should include a check of melt flow rate, density, ash content, and flexural modulus on each lot according to the supplier’s certificate of analysis. Incoming resin should be stored in sealed bags below 40 °C, away from direct sunlight, and consumed within 12 months of manufacture. Contamination with polyethylene or foreign pellets above 0.5 wt% can reduce properties and should be controlled by silo and hopper cleaning. These operational boundaries allow the grade to be introduced into existing polypropylene injection-molding conversions without extensive retooling, provided the mold, gating, and process parameters are validated against the actual lot data.
