LG Chem HDPE SM5500
- Product Name: LG Chem HDPE SM5500
- Factroy Site: Yudu County, Ganzhou, Jiangxi, China
- Price Inquiry: admin@ascent-chem.com
- Manufacturer: Ascent Petrochem Holdings Co., Limited
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- LG Chem HDPE SM5500 is typically used in formulations when melt flow rate and density and processing temperature and pressure must be controlled within specific ranges.
| HS Code | 140077 |
| Product Name | LG Chem HDPE SM5500 |
| Polymer Type | High Density Polyethylene (HDPE) |
| Density | 0.955 g/cm³ |
| Melt Flow Rate 190 C 2 16 Kg | 0.35 g/10 min |
| Melt Flow Rate 190 C 21 6 Kg | 25 g/10 min |
| Tensile Strength At Yield | 28 MPa |
| Tensile Strength At Break | 30 MPa |
| Elongation At Break | >600% |
| Flexural Modulus | 1200 MPa |
| Notched Izod Impact Strength 23 C | 20 kJ/m² |
| Hardness Shore D | 65 |
| Vicat Softening Temperature | 125°C |
| Melting Point | 133°C |
| Heat Deflection Temperature 0 45 Mpa | 75°C |
| Environmental Stress Cracking Resistance F50 10 Igepal | >1000 h |
As an accredited LG Chem HDPE SM5500 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | LG Chem HDPE SM5500 is supplied in 25 kg bags or 1,000 kg jumbo bags, typically 20 MT per container. |
| Container Loading (20′ FCL) | 20′ FCL: 25 kg bags, loose loaded, approx. 17.5 MT net, around 700 bags per container. |
| Shipping | LG Chem HDPE SM5500 is shipped as non-hazardous thermoplastic resin pellets in 25 kg bags, jumbo bags, or bulk trucks/containers. Store dry, away from direct sunlight, heat, and contamination. Standard land/sea transport applies; no dangerous goods classification required. |
| Storage | Store LG Chem HDPE SM5500 in a cool, dry, well-ventilated warehouse. Keep original bags or containers tightly closed, away from direct sunlight, heat, ignition sources, moisture, and incompatible materials. Protect from contamination and physical damage. Maintain good housekeeping to prevent dust accumulation; use first-in, first-out stock rotation. Avoid excessive temperatures that may cause softening or degradation. Follow local storage regulations. |
| Shelf Life | LG Chem HDPE SM5500 shelf life is typically 24 months from production when stored unopened in a cool, dry, well-ventilated area. |
Thin-wall dairy packaging remains the highest-volume injection moulding segment for LG Chem HDPE SM5500 because the grade’s high melt flow permits cavity filling in stack moulds with wall sections between 0.35 mm and 0.80 mm. The grade is specified with a melt flow rate in the 50–60 g/10 min range under ISO 1133-1:2022 at 190 °C/2.16 kg, and density between 0.960 g/cm³ and 0.964 g/cm³ by ISO 1183-1. On a 200–350 t toggle-clamp injection moulding machine with screw diameter 40–60 mm and L/D 20:1–25:1, barrel-zone setpoints are commonly 190–220 °C, the hot-runner manifold is held at 210–235 °C, and the chilled-water mould is controlled at 8–25 °C. Injection velocity profiles range 120–220 mm/s; peak filling pressure typically falls between 800 bar and 1,200 bar, measured at the nozzle rather than the hydraulic circuit. Hold pressure is set at 50–70 % of peak cavity pressure, with hold time 0.4–1.2 s for thin sidewalls and 1.0–2.0 s for rim-heavy lid geometries. Screw rotation backpressure is kept at 5–10 bar to avoid excessive melt shear heating; screw recovery should complete before the cooling timer expires to prevent idle time on the clamp. For food-contact white dairy tubs, the compound is let down with 2–4 wt% TiO₂ white masterbatch in an HDPE carrier and 0.5–1.0 wt% slip/antiblock masterbatch, keeping total additive loading below 5 wt% to prevent plate-out on core pins and inconsistent colour dispersion. Shrinkage allowance is 1.2–1.8 % in flow and 1.0–1.5 % cross-flow, adjusted after cavity-pressure studies because high hold stress in thin ribs can produce post-mould warpage. Compliance follows FDA 21 CFR §177.1520(c) 2.1, EU 10/2011, and the overall migration limit of 10 mg/dm² for the finished article. Terminal parts include 250 mL dairy cups, 500 g margarine tubs, dessert cups, and snap-on lids for fresh dairy packaging.
How Does SM5500 Respond to High-Cavitation Closure Moulds with Undercut Stripping?
Under high-cavitation closure production, SM5500 fill behaviour reduces the hydraulic pressure required to fill 28 mm and 38 mm closure shells, but the high melt flow demands nozzle shut-off and post-plastication decompression of 2–4 mm to control drool at the sprue bushing. A 64-cavity cold-runner mould with edge gates of 0.6–1.2 mm diameter per cavity produces fill times of 0.3–0.8 s at melt temperatures 210–235 °C. Mould temperature is held at 10–20 °C, and closure ejection is timed after seal-ring formation but before the part reaches full ambient crystallisation to avoid undercut damage. Screw backpressure is limited to 5–12 bar; barrel profile is 190/210/215/220/220 °C from feed to nozzle. Hold pressure is set to 60–80 % of dynamic filling pressure for 0.8–2.0 s, and total cycle times on 250–350 t machines range 6–12 s for single-piece closure shells. Formulation for non-barrier closures uses 100 parts SM5500 with 1–2 wt% slip masterbatch and 0.2–0.5 wt% processing antioxidant; coloured closures add 2–3 wt% colour masterbatch. The grade is not specified for carbonated soft-drink closures without a barrier liner or PP/PCO neck geometry because steady-state CO₂ permeability through HDPE is too high for long shelf-life carbonation retention. Food-contact closure shells are evaluated under FDA 21 CFR §177.1520 for olefin polymers, EU 10/2011, and taste/odour migration testing methods such as EN 1622. Terminal products include tamper-evident water, dairy, and ready-to-drink beverage closures with breakaway bridge dimensions below 0.35 mm.
When SM5500 is moulded into open-top industrial pails, the primary processing conflict is balancing high flow for fast fill against gate blush and jetting created by small sprue gates. Direct sprue or diaphragm gating with gate diameter 2.5–4.0 mm is standard for wall thickness 1.5–3.0 mm; smaller gates produce splay, rippling, and reduced top-load strength at the injection point. Barrel temperatures are set at 180–210 °C, mould temperature 10–25 °C, fill time 1.5–4.0 s, hold time 8–15 s for 10 L pail geometry, and cooling time 12–25 s depending on wall stock. For outdoor and pigmented pails, the formulation is 100 parts SM5500 with 2–5 wt% UV-stabilized masterbatch and 2–3 wt% colour masterbatch; in-plant regrind from cold-runner sprues is reincorporated at 10–20 wt% after melt-flow verification because repeated heat histories can shift the flow distribution and reduce pail sidewall impact strength. Drop testing at -18 °C after conditioning for 48 h is commonly performed according to ASTM D5276; UN dangerous-goods pails are additionally assessed under ADR 6.1.5 or equivalent national transport packaging certification. The high melt flow of SM5500 reduces environmental stress crack resistance relative to high-molecular-weight bimodal HDPE, so pails for aggressive solvents or continuous chemical contact above 40 °C should be validated by ASTM D1693 on the actual finished part before commercial release. Published ESCR data for this specific grade in aggressive solvent environments is limited, and finished-part testing is required. Terminal products include 5 L, 10 L, and 20 L open-top pails for water-based paints, food powders, mineral fillers, and construction chemicals.
Stacking Creep and Gate-Freeze Rates in Crate and Tote Processing
Multiple-gated crate and tote tools using SM5500 are more sensitive to knit-line impact loss than lower-flow HDPE grades because the melt front temperature drops rapidly across the long flow path. Sequential valve-gate hot runner systems with 4–8 drops are used for parts with wall thickness 1.5–3.5 mm; gate opening is sequenced at 0.2–0.5 s intervals to move the flow fronts together. Melt temperature at the nozzle is maintained at 190–220 °C, with mould temperature 15–35 °C; fill velocity is reduced to 60–150 mm/s for large shot weights to prevent flow hesitation between gates. Total cycle time for 30 L warehouse totes is typically 30–55 s on machines with clamp force 500–800 t. The formulation uses 100 parts SM5500 plus 3–5 wt% colour masterbatch, with up to 20 wt% clean in-house regrind; addition of 0.1–0.3 wt% nucleating agent can shorten demould time, but must be validated against top-load retention and impact after 48 h oven ageing at 60 °C. Stacking load retention for filled crates is evaluated under ISO 12048 compression conditions or ASTM D642; corner postbuckling rather than mid-panel creep usually limits the practical stack height. Terminal products include beverage crates, warehouse totes, folded container sidewalls, and institutional storage bins.
When Living Hinge Geometry Is Applied to SM5500 in Kitchenware
SM5500 is processable in kitchen storage boxes and trays, but its high-flow HDPE molecular structure is not the primary choice for integral living hinges thinner than 0.25 mm because repeated flexural fatigue under standard kitchen-use deflection can produce whitening and cracking before polypropylene homopolymer counterparts. Published flex-fatigue data for this specific high-flow HDPE grade in living-hinge configurations is limited, so hinge life must be tested on the actual moulded hinge rather than extrapolated from general polyolefin data. If a hinge is required, the hinge web should be 0.25–0.40 mm thick with a notch radius no tighter than 0.2 mm, and the tool should be gated away from the hinge to preserve molecular orientation across the line of flex. Gloss-surfaced containers are produced with melt temperatures 200–220 °C, mould temperatures 30–50 °C, and extended cooling time 10–25 s to reduce sink marks around thick rims; thin wall areas are filled at 80–160 mm/s. Formulation for food-adjacent kitchenware uses 100 parts SM5500 with 1–3 wt% slip/anti-scratch masterbatch and 1–2 wt% colour masterbatch; when the articles are intended for repeated food contact, migration testing follows EN 1186 series conditions appropriate to the food simulant. Terminal products include cereal storage boxes, refrigerator organizers, kitchen bowls, lids for dry-food canisters, and trays with snap-fit features.
Laboratory consumables moulded from SM5500 are limited to non-implantable, single-use or reusable diagnostic and general labware where high injection productivity and resistance to aqueous buffers are primary requirements. The chosen melt temperature window is 190–210 °C, with mould temperature 10–25 °C on 120–250 t injection moulding machines equipped with screw diameter 35–60 mm. Tools are run in ISO 14644-1 Class 8 or cleaner cleanrooms when the moulded part is used as a diagnostic consumable. The formulation uses 100 parts SM5500 with 0.5–1.0 wt% internal antistatic masterbatch where powder handling necessitates static dissipation; slip additives are kept below 0.5 wt% because surface bloom can alter contact angle and interfere with reagent deposition or label adhesion. Cytotoxicity and irritation screening are commonly conducted under ISO 10993-5 and ISO 10993-10 for diagnostic disposables, while EU 2017/746 applies to in-vitro diagnostic medical device components. Terminal products include specimen containers, single-use scoops, cuvette trays, reagent reservoirs, and packaging inserts for in-vitro diagnostic kits.
| Downstream segment | Melt temperature (°C) | Mould temperature (°C) | Fill time (s) | Hold pressure (% of peak) |
|---|---|---|---|---|
| Thin-wall dairy packaging | 190–220 | 8–25 | 0.4–1.2 | 50–70 |
| Closures | 210–235 | 10–20 | 0.3–0.8 | 60–80 |
| Industrial pails | 180–210 | 10–25 | 1.5–4.0 | 60–80 |
| Crates and totes | 190–220 | 15–35 | Sequenced valve gate | 60–80 |
| Kitchenware | 200–220 | 30–50 | 80–160 mm/s | 50–70 |
| Laboratory consumables | 190–210 | 10–25 | 0.5–2.0 | 50–70 |
| Segment | Regulation / standard | Typical requirement or method |
|---|---|---|
| Thin-wall dairy packaging | FDA 21 CFR §177.1520(c) 2.1; EU 10/2011 | Overall migration limit 10 mg/dm² |
| Closures | FDA 21 CFR §177.1520; EU 10/2011 | Taste and odour migration under EN 1622 |
| Industrial pails | ADR 6.1.5 | Drop test -18 °C per ASTM D5276; ESCR per ASTM D1693 |
| Crates and totes | ISO 12048; ASTM D642 | Compression and stack load retention |
| Kitchenware | FDA 21 CFR §177.1520; EU 10/2011 | Migration series EN 1186 |
| Laboratory consumables | ISO 10993-5; ISO 10993-10; EU 2017/746 | Cytotoxicity, irritation, IVDR component compliance |
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- LG Chem HDPE SM5500 is manufactured under an ISO 9001 quality system and complies with relevant regulatory requirements.
- COA, SDS/MSDS, and related certificates are available upon request. For certificate requests or inquiries, contact: admin@ascent-chem.com.
LG Chem HDPE SM5500 is a high-density polyethylene injection molding grade characterized by a nominal melt flow index of 5.5 g/10 min measured at 190 °C under a 2.16 kg load in accordance with ISO 1133-1:2022 and a nominal density of 0.955 g/cm³ determined by ISO 1183-1:2019. The product is supplied in pellet form and is intended for thin-wall packaging, caps and closures, crates, pails, housewares, and similar rigid injection molded articles. The melt flow index is higher than that of typical HDPE blow-molding and blown film grades, which generally reside below 1.0 g/10 min; this difference lowers melt viscosity and permits shorter filling times. The density near 0.955 g/cm³ contributes to flexural stiffness and top-load strength in finished parts. SM5500 is not designed for extrusion blow molding of large containers or for blown film, where higher melt strength and higher environmental stress-cracking resistance are required.
What Are the Reference Mechanical and Thermal Values for SM5500?
Manufacturer data sheets typically report the following values from compression-molded specimens conditioned at 23 °C and 50 % relative humidity under ISO 291:2008. They are typical values, not minimum or maximum contractual specifications.
| Property | Test method | Typical value |
|---|---|---|
| Melt flow index, 190 °C/2.16 kg | ISO 1133-1:2022 | 5.5 g/10 min |
| Density | ISO 1183-1:2019 | 0.955 g/cm³ |
| Tensile stress at yield | ISO 527-2:2012 | 26 MPa |
| Tensile elongation at break | ISO 527-2:2012 | >600 % |
| Flexural modulus | ISO 178:2019 | 1,050 MPa |
| Vicat softening temperature, A50 | ISO 306:2022 | 124 °C |
| Melting peak temperature | ISO 11357-3:2018 | 132 °C |
| Shore D hardness | ISO 868:2021 | 62 |
The reported flexural modulus of 1,050 MPa is consistent with a density of 0.955 g/cm³. Compared with lower-density HDPE grades in the 0.940–0.950 g/cm³ range, SM5500 generally provides higher rigidity at the expense of impact and stress-cracking resistance. The melt flow index of 5.5 g/10 min is significantly higher than the 0.3–1.0 g/10 min values typical of high-molecular-weight blow-molding and film resins. The higher flow reduces melt pressure in thin sections but also reduces orientation ability and melt strength. Comparative environmental stress-cracking resistance values under ASTM D1693 condition B are not published for this specific grade. Where ESCR is critical, the finished part should be tested in the intended contact fluid at service temperature.
Rheological Behavior, Drying, and Melt-Temperature Limits in Injection Molding
SM5500 exhibits pseudoplastic behavior above the melting peak of approximately 132 °C. Melt viscosity decreases with increasing shear rate, so higher injection speeds improve flow without a proportional increase in hydraulic pressure. The recommended melt temperature window for injection molding is 190–220 °C, with mold temperatures between 15 °C and 40 °C depending on surface finish and part thickness. Processing above 240 °C or at total residence times beyond 15 min should be avoided because the grade is not specifically stabilized for extended high-temperature hold-up. Published oxidative induction time data for SM5500 is limited; therefore, the onset of discoloration and loss of impact at elevated temperatures must be established on the specific molding line.
Because HDPE is essentially non-hygroscopic, predrying is not mandatory for virgin pellets. However, condensation on cold pellets or wet regrind can introduce surface moisture. If pellet surface moisture exceeds 0.05 wt%, splay, weld-line strength loss, or inconsistent feeding may occur. In practice, regrind containing residual water should be dried at 80 °C for 2 h in a desiccant or hot-air hopper dryer. Blend ratios above 30 % regrind can shift the melt flow index upward and reduce notched impact; the actual shift depends on thermal history and grinding fines content. Fines below 500 µm should be limited because they can cause feeding instability and non-uniform melting.
On a 200-ton hydraulic injection molding machine with a 20:1 L/D general-purpose screw, a barrel profile of 180/190/195/200 °C from feed to nozzle is a typical starting point for SM5500. Back pressure of 0.3–0.7 MPa and screw surface speed of 0.2–0.4 m/s help maintain melt homogeneity without excessive shear heating. Multi-cavity closures and thin-wall containers may require injection pressures of 80–110 MPa and hold pressures of 50–80 MPa. The exact values depend on gate diameter, flow-length-to-wall-thickness ratio, and mold steel temperature. Cavities with flow-length ratios above 200:1 may require melt temperatures at the upper end of the range, but the associated loss of thermal stability must be monitored through purge shots and melt-pressure consistency.
Short-shot and flash boundaries are shifted by the grade’s medium flow. When wall thickness drops below 0.6 mm, the flow-length-to-thickness ratio can exceed 250:1 at melt temperatures below 200 °C, and the cavity may freeze before full packing. In high-speed closure tools, packing pressure must be transferred before the gate freezes. For an edge gate of 0.8 mm diameter, gate freeze time for HDPE at a mold temperature of 20 °C is approximately 1–2 s. If hold pressure is not applied within that interval, sink marks, warpage, and dimensional variation increase. The grade’s viscosity is not designed for very thin-wall packaging below 0.5 mm with flow-length ratios above 300:1; higher-flow HDPE grades, typically >10 g/10 min, may be required.
A comparison of SM5500 with high-molecular-weight HDPE blow-molding grades and blown film grades clarifies the application envelope. Blow-molding grades are generally formulated with melt flow indices below 1.0 g/10 min to provide high melt strength and parison stability. SM5500, at 5.5 g/10 min, has lower melt strength and is more prone to parison sag in extrusion blow molding. High-density film grades often have a density similar to SM5500 but are designed for bubble stability and draw-down; their molecular weight distribution and comonomer content are optimized for film impact and tear. SM5500 may have lower dart impact and lower ESCR than HDPE film grades, but it provides better flow for injection molding. When replacing a blow-molding grade in a cap or closure design, the higher flow can reduce cycle time, yet the part may require a tougher design or thicker ribs to compensate for reduced resistance to slow crack growth.
When SM5500 Is Substituted for Lower-Melt-Index HDPE Grades in Thin-Wall Tooling
The melt flow index of 5.5 g/10 min is sufficiently high to fill reduced wall sections. In conventional thin-wall packaging, lowering wall thickness from 1.5 mm to 0.8 mm may require a melt index increase from roughly 1.5 g/10 min to 5 g/10 min. SM5500 falls within this range. The resulting pressure drop across the cavity is lower, which can reduce clamp force requirements on multi-cavity tools. A 200-ton clamp may run a multi-cavity closure tool with SM5500 where a higher-viscosity HDPE would require 250 tons or more; however, this depends on projected area and cavity spacing. Batch-to-batch variation in melt flow index should be controlled because a shift of 0.5 g/10 min or more can change peak injection pressure and part dimensions. Density should remain within 0.954–0.956 g/cm³ to avoid stiffness variation.
Gate freeze time is shorter with higher melt flow grades but is dominated by part thickness and mold temperature. The higher flow may permit a slight reduction in melt temperature, but reducing melt temperature below 190 °C can cause surface flow marks, incomplete weld-line healing, and increased gate stress. When weld lines occur in closure knurls or living hinge areas, the melt should be kept at the upper end of the range and the mold should be maintained above 20 °C. However, higher mold temperatures reduce cooling rate and can increase cycle time if cooling channels are not designed for turbulent flow. Cooling circuits should maintain Reynolds numbers above 10,000 to prevent the transition to laminar flow and the associated loss of heat removal.
Substitution into designs originally qualified for a lower-melt-index HDPE requires revalidation of top-load strength, drop impact, and stress-cracking resistance. The higher melt index can lower tensile impact and notched Izod, particularly at weld lines and around molded-in inserts. Environmental stress-cracking resistance should be measured under ASTM D1693 condition B or ISO 22088-2 with the actual service fluid. Published data for SM5500 under these protocols is limited; qualifying in the end-use chemical is necessary. The grade is not intended for pressure-pipe extrusion or geomembrane applications, where hydrostatic strength requirements under ISO 9080 and slow crack growth resistance under ISO 16770 are controlling.
Chemical Resistance and Regulatory Boundaries Must Be Verified Per Application
As a high-density polyethylene with density 0.955 g/cm³, SM5500 resists many dilute inorganic acids, alkalis, and polar solvents at temperatures up to 40 °C. It is not recommended for strong oxidizing acids, chlorinated solvents, or aromatic and aliphatic hydrocarbons above 60 °C because swelling and extractive loss can alter dimensions and mechanical properties. For food-contact use, HDPE grades are often represented as compliant with 21 CFR 177.1520 for olefin polymers. The FDA status applies to the base resin; the finished article must meet migration limits in 21 CFR 177.1520(b), and colorants or additives must have their own food-contact authorizations. EU food-contact compliance requires evaluation under Regulation (EU) No 10/2011, including overall migration and specific migration limits for any additives used. REACH and RoHS declarations are not automatic; the supplier should be asked for product-specific documentation.
In pharmaceutical and personal-care packaging, the grade may be used for closures, but interactions with active ingredients, flavor compounds, or essential oils require extraction testing under USP <661.1> or equivalent. High-shear molding at elevated temperatures can generate trace volatiles; ventilation and melt-temperature control should be included in mold area design. If pellets are stored at relative humidity above 60 %, condensation on cold pellet surfaces may occur when transferred to a warm hopper; surface moisture should be removed before molding. The material is not intended for outdoor UV exposure without an approved UV stabilizer package, and even then long-term weatherability should be tested under ISO 4892-2 or ASTM D2565.
