Dow HDPE DMDA-6200 NT7
- Product Name: Dow HDPE DMDA-6200 NT7
- Factroy Site: Yinchuan, Ningxia, China
- Price Inquiry: sales8@ascent-chem.com
- Manufacturer: Ascent Petrochem Holdings Co., Limited
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- Dow HDPE DMDA-6200 NT7 is typically used in formulations when melt flow rate, density, and molecular weight distribution and melt temperature, extrusion pressure, and mold temperature must be controlled within specific ranges.
| HS Code | 665179 |
| Density | 0.953 g/cm³ |
| Melt Index 190 C 2 16 Kg | 0.35 g/10 min |
| High Load Melt Index 190 C 21 6 Kg | 25 g/10 min |
| Tensile Strength At Yield | 24 MPa |
| Tensile Strength At Break | 30 MPa |
| Elongation At Break | 600% |
| Flexural Modulus | 1100 MPa |
| Vicat Softening Point | 127°C |
| Heat Deflection Temperature At 0 45 Mpa | 73°C |
| Brittleness Temperature | -70°C |
| Shore D Hardness | 66 |
| Environmental Stress Crack Resistance 10 Igepal F50 | >1000 h |
| Melting Point | 132°C |
| Molecular Weight Distribution | Narrow |
| Mold Shrinkage | 1.5-2.0% |
| Water Absorption | <0.01% |
As an accredited Dow HDPE DMDA-6200 NT7 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Dow HDPE DMDA-6200 NT7 is supplied in 25 kg polyethylene bags, palletized and shrink-wrapped for industrial shipment. |
| Container Loading (20′ FCL) | Container Loading (20′ FCL): Dow HDPE DMDA-6200 NT7 in 25 kg bags, palletized, shrink-wrapped, and securely loaded for ocean shipment. |
| Shipping | Dow HDPE DMDA-6200 NT7 is shipped as non-hazardous polyethylene resin pellets. Typical packaging includes 25 kg bags, bulk bags, or bulk trucks/railcars. Transport in clean, dry vehicles, avoiding moisture, heat, direct sunlight, and contamination. Follow Dow’s SDS and applicable transport regulations; no dangerous-goods placards are normally required. |
| Storage | Store Dow HDPE DMDA-6200 NT7 in a cool, dry, well-ventilated area away from direct sunlight, heat, sparks, flames, and strong oxidizers. Keep original containers or bags tightly closed to prevent moisture, dust, and contamination. Avoid prolonged UV exposure and excessive stacking. Maintain good housekeeping; use appropriate grounding if handling bulk powder/pellets to control static. |
| Shelf Life | Dow HDPE DMDA-6200 NT7 typically has a 24-month shelf life when stored dry, unopened, and protected from heat and direct sunlight. |
DMDA-6200 NT7 is a high-density polyethylene grade characterized by a nominal melt index of 0.15 g/10 min at 190°C under 2.16 kg load when tested in accordance with ASTM D1238, and a nominal density of 0.953 g/cm³ when tested in accordance with ASTM D792. The grade is not a high-flow injection molding resin, and the downstream tracks below are limited to extrusion blow molding and coextrusion blow molding operations where high melt strength, stiffness, and environmental stress crack resistance control article performance. Hopper drying at 70–80°C for 2 h is used only when ambient relative humidity exceeds 60%; HDPE is not hygroscopic, but surface condensation on pellets can produce splay in pinch-off welds and shot-weight variation.
Incoming resin surveillance and finished-part qualification for the downstream tracks below reference the following test designations:
| Property or test condition | Standard method | Relevance in blow molded articles |
|---|---|---|
| Melt index at 190°C/2.16 kg | ASTM D1238 | Controls extruder back pressure, parison hang strength, and shot-weight stability |
| Density | ASTM D792 | Sets crystallinity, top-load stiffness, and permeation resistance |
| Environmental stress crack resistance | ASTM D1693 Condition B, 10% Igepal, 50°C | Predicts service life with detergent, wetting agent, and metalworking fluid contact |
| Tensile yield strength | ASTM D638 | Input for hydrostatic pressure and stacking calculations |
| Flexural modulus | ASTM D790 | Influences sidewall stiffness and handle deflection under load |
On long-stroke shuttle blow molding lines fitted with 30:1 L/D grooved-barrel extruders and first-in first-out accumulator heads, DMDA-6200 NT7 is processed with rear-to-die set points from 180°C to 220°C. The die head is held within ±3°C to limit viscosity drift that would otherwise shift parison wall thickness distribution. The low melt index of 0.15 g/10 min generates high back pressure at the breaker plate, so accumulator heads with positive melt displacement are preferred over continuous-extrusion heads for drums above 20 L. Clean post-industrial regrind from flash and top/tail trims is ground through a 6 mm screen and metered into the hopper at 20–35 wt%; color masterbatch is added at 1–2 wt%, and UV stabilizer masterbatch at 2–3 wt% for outdoor storage. Blow air is supplied at 0.6–0.8 MPa through dual-orifice needles to achieve sidewall contact before freeze-off. Mold coolant is maintained at 10–20°C; demolding is delayed until the part surface reaches 45–55°C to reduce post-mold shrinkage variability. The melt temperature must not exceed 230°C; local shear heating can create gel-like degradation particles that concentrate in the pinch-off weld and reduce low-temperature drop resistance. The limiting failure mode in this segment is not hydrostatic burst but pinch-off weld tearing: flash thickness greater than 0.5 mm at the lower seam indicates insufficient pinch compression, while an excessively thin seam fails the UN drop test at low temperature. For UN 1H1 closed-head or 1H2 open-head drums, compliance is established by drop testing under 49 CFR 178.603, hydrostatic pressure testing under 178.605, and stack testing under 178.606. Tensile yield, flexural modulus, and environmental stress crack resistance are tracked under ASTM D638, ASTM D790, and ASTM D1693 Condition B. The terminal articles are 20–30 L open-head and closed-head drums for industrial detergent concentrates, metalworking fluid additives, and water treatment chemicals. Field-scale failure roots in this application include shot-weight drift caused by barrel temperature cycling, die lines from contaminated accumulator mandrels, and lid ovality when cooling fixtures are not aligned with the part population.
What ESCR Variables Govern Agrochemical Container Performance?
In agrochemical service, the bottle or jug is exposed to surfactants, aromatic hydrocarbon cosolvents, and ester solvents that act as stress-cracking agents at molded-in stresses in the handle and pinch-off weld. For 0.5 L, 5 L, and 20 L F-style containers, the converter should specify ESCR testing on the actual molded article rather than on a compression-molded plaque because the handle-to-wall transition can fail at loads well below bulk tensile yield. DMDA-6200 NT7 requires a sidewall minimum of 0.8 mm in the handle bridge; thinner sections show a nonlinear loss of ESCR performance. Process settings are shifted to slightly lower melt temperatures of 190–210°C to prevent oxidative chain scission, while mold temperature is held at 15–25°C to balance cycle time with residual stress. Regrind level is held to 15–25 wt%, and UV stabilizer masterbatch is added at 2–4 wt% for exterior storage. For liquid products classified under UN Packing Group II, drop height is 1.2 m for specific gravity ≤1.2; for Packing Group III it is 0.8 m. Closure torque retention is also measured at end-of-line because HDPE thread relaxation after filling can loosen caps; neck finishes should be calibrated to the closure manufacturer’s dimensional standard. The terminal products are herbicide, fungicide, and adjuvant jugs from 0.5 L to 20 L; high-volatile aromatic fractions above 30 wt% require fluorination or a barrier insert because monolayer HDPE permeation becomes the dominant weight-loss mechanism.
Passenger car windshield washer reservoirs are produced on continuous shuttle blow molders with multi-clamp tools; the technical risk in this downstream sector is cold-impact embrittlement at the pump socket, not long-term environmental stress cracking. DMDA-6200 NT7 is run at 200–230°C with a 24:1–25:1 L/D general-purpose screw; because the low melt index creates shear heating, screw speed is constrained so the melt exit does not exceed 230°C. The part receives carbon black masterbatch at 1.5–2.5 wt% for UV screening, and clean regrind is held below 25 wt% because fines from over-ground scrap destabilize feed throat conveying. Blow air at 0.7–0.9 MPa is required to push the thick parison into side-core and insert retention regions. Mold temperature is set to 10–20°C; lower mold temperature improves gloss but can create differential cooling around the pump boss, producing post-demolding warpage. Validation uses tensile modulus under ISO 527-2, Charpy notched impact under ISO 179-1, and heat aging at 90–100°C to simulate under-hood service. Continuous operating pressure remains atmospheric; the material is not qualified for pressurized coolant expansion tanks above 1.2 bar because long-term creep at 110°C can distort the neck seal surface. The terminal products are floor-mounted and firewall-mounted washer bottles of 2–5 L with integrated pump sockets.
Water Treatment Vessel Liners and Constant-Hydrostatic-Pressure Service
Point-of-use reverse osmosis storage tank liners are extrusion blow molded as seamless shells that later receive epoxy/glass filament winding. In this track, DMDA-6200 NT7 is processed on accumulator equipment with a programmed wall thickness of 2.0–3.5 mm in the dome and bottom chime. Processing aids are excluded to avoid extraction risk, and clean regrind is limited to 10–20 wt%; calcium carbonate filler above 5 wt% is not recommended because it lowers environmental stress crack resistance and raises ash content in formulation review. Blow air is filtered to 0.01 µm to prevent oil contamination of the inner surface. Compliance for potable water contact requires extraction testing under NSF/ANSI 61, compliance with the food-contact olefin polymer provisions of FDA 21 CFR 177.1520, and migration testing under Regulation (EU) No 10/2011 where applicable. The terminal product is a 3.2-gallon reverse osmosis storage tank liner that is then filament-wound under controlled tension; the liner must not exhibit inner-surface pitting because pitting acts as an initiation site for cyclic fatigue cracks. Published data for this specific liner configuration is limited, and converters must qualify the exact blow molding cycle on the tank manufacturer’s final pressure-cycling rig.
When a 3-Layer Coextrusion Head Requires a High-Stiffness Structural HDPE Skin
For household and institutional cleaning concentrates that contain hypochlorite or solvent blends, monolayer HDPE often fails through environmental stress cracking or odor permeation; a three-layer structure places DMDA-6200 NT7 as the inner and outer structural skins around an EVOH barrier core. The die arrangement typically uses two HDPE extruders and one barrier/tie system; the HDPE layer is set to 200–220°C, tie resin to 190–210°C, and EVOH to 185–195°C. Keeping the HDPE skin at least 0.5 mm thick prevents the barrier layer from migrating toward the surface during parison inflation. Regrind is not placed in the visible outer skin; it is metered into the core or inner skin at 20–30 wt% after density separation. Interfacial adhesion is checked by peel test on cut bottle sidewalls or by drop testing from 1.2 m at -18°C. Top-load retention after filling is measured under ASTM D2659, with acceptance set by the packer’s palletizing requirements and closure torque specification. The terminal articles are 0.75–1.5 L bottles for ready-to-use and dilute-at-use disinfectant formulations, pool chemicals, and floor strippers. The operational boundary is that the HDPE skins are not solvent-resistant; if the concentrate contains more than 10 wt% polar solvent, the inner layer should be replaced by a more resistant polyolefin or fluorinated surface treatment.
Marine non-potable fluid tanks for greywater and sanitation service are blow molded in short runs with manual mold changes; the part geometry includes flat sidewalls and welded spigots that create localized stress under wave-induced sloshing. DMDA-6200 NT7 is processed at 190–220°C with an accumulator head and a 50-point parison programmer to maintain wall thickness above 2.0 mm in chime corners. Because the part is installed in a compartment where ambient temperature can exceed 60°C, the fixings must distribute load across molded-in brass inserts, not point-load the HDPE. Formulation for this service includes carbon black or grey pigmentation at 2–3 wt% and clean regrind at 10–20 wt%; no volatile processing aid is used. Compliance for marine sanitation equipment in the US market falls under 33 CFR 159 for sanitary devices and may require odor-permeation testing under the equipment builder’s specification. The terminal product is a holding tank of 10–40 L for greywater or bilge water, excluding fuel or solvent cargo. The operational boundary is immediate: HDPE is not suitable for gasoline, diesel, or solvent-based bilge mixtures at elevated temperature due to permeation and softening; such fluids require alternative barrier constructions.
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- Dow HDPE DMDA-6200 NT7 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: sales8@ascent-chem.com.
Dow HDPE DMDA-6200 NT7 is a high-density polyethylene homopolymer resin developed for extrusion blow molding of rigid containers. Supplier-published typical values list a density of 0.953 g/cm³ when tested in accordance with ASTM D1505 and a melt flow index of 0.20 g/10 min under a 2.16 kg load at 190°C as defined by ASTM D1238. These figures place the grade in the medium-high molecular weight segment for HDPE blow molding resins, where melt strength is sufficient for parison stability on shuttle and continuous extrusion lines without the high extruder backpressure and low output associated with fractional-melt resins. The density is deliberately maintained near the high end of the HDPE blow molding range to increase crystallinity and stiffness, while the molecular weight and molecular weight distribution are controlled to retain environmental stress crack resistance.
In end-use terms, DMDA-6200 NT7 is specified for extrusion blow molded containers between 500 mL and 30 L, with common wall thicknesses from 0.6 mm to 3.0 mm depending on stack load, fill temperature, and package geometry. Application areas include household and industrial chemical containers, agricultural chemical packaging, detergent and cosmetic bottles, and food-contact articles where the converted package meets applicable migration limits. The resin is also processed in coextruded structures where a high-density polyethylene outer layer supplies rigidity and the contribution of the layer to water vapor permeation is evaluated by film or sheet methods such as ASTM F1249 or ISO 15106-3. Container qualification typically includes drop impact per ASTM D2463 and top-load compression per ASTM D2659 to verify performance after filling and capping.
What separates DMDA-6200 NT7 from lower-density and higher-melt-index HDPE grades?
Compared with a lower-density HDPE blow molding grade at approximately 0.949 g/cm³, DMDA-6200 NT7 shifts the balance toward flexural modulus and top-load strength. The density difference from 0.949 to 0.953 g/cm³ is not merely an incremental shift; it corresponds to greater crystallinity and a measurable increase in elastic modulus as captured by ASTM D790. At the same time, environmental stress crack resistance measured by ASTM D1693 Condition B remains above 600 h, indicating that the grade does not sacrifice long-term chemical resistance for stiffness in the same manner as a simple density increase would suggest. Higher-melt-index HDPE blow molding grades, typically between 0.30 g/10 min and 0.60 g/10 min, allow faster extrusion at lower head pressure but exhibit greater parison sag and reduced hang strength, particularly on tools with long parison lengths or complex pinch-off geometries. Fractional-melt grades near 0.05 g/10 min can provide higher ESCR plateaus but generally require melt temperatures above 204°C to maintain manageable head pressure, which narrows the temperature window on older shuttle machines and can increase polymer degradation at stagnant melt zones.
The product also differs from injection molding HDPE grades with melt flow indices of 4 g/10 min to 20 g/10 min in molecular architecture and processing orientation. Those grades are optimized for spiral flow, rapid cooling, and thin-wall injection, while DMDA-6200 NT7 is optimized for extensional melt deformation during parison formation and blow-up. Using an injection molding grade in extrusion blow molding typically leads to parison instability and lower ESCR; using DMDA-6200 NT7 in injection molding is not recommended because the low melt flow index reduces filling behavior and increases injection pressure.
On production-scale shuttle blow molders with a 50 mm to 75 mm extruder and a length-to-diameter ratio of 24:1, the material is typically processed at a melt temperature between 177°C and 204°C. Die temperatures are held at 193°C to 210°C, while mold temperatures are maintained between 10°C and 30°C unless dimensional control requires chilled water. Blow-up ratios are generally limited to 2.0:1 through 3.0:1; beyond this range, wall thinning at the pinch-off and shoulder regions becomes difficult to control. The resin is not hygroscopic, so pre-drying is not normally required. However, when cold resin is transferred into a warm processing hall with relative humidity above 60%, surface condensation can produce splay and intermittent parison bubble instability. The material should not be blended with acid-functional polymers or unmodified recycled polypropylene in high percentages because weld-line strength may fall below the levels required for ASTM D2463 drop impact qualification. Processing at melt temperatures above 210°C is generally outside the intended window for thin-wall containers because parison sag increases and wall thickness distribution may become unacceptable in containers with walls below 0.8 mm.
Capillary rheometry at 190°C can be used to generate viscosity curves needed for parison programming. Typical linear HDPE melts with 0.20 g/10 min melt flow index show shear-thinning behavior; apparent viscosity decreases by roughly one order of magnitude when shear rate increases from 1 s⁻¹ to 100 s⁻¹. Process engineers use this relationship to adjust die gap and extrusion speed independently: widening the die gap from 0.8 mm to 1.2 mm reduces shear rate at a given output, lowers die swell variation, and improves parison wall uniformity. However, excessive die gap can reduce parison line speed and increase exposure to sag. On continuous wheel machines, die head temperature ramps of ±5°C have been observed to shift parison length by approximately 2%, which is sufficient to affect pinch-off weld thickness when the wall target is below 0.8 mm.
Mechanical and thermal property thresholds after wall-thickness optimization
The following typical values are taken from supplier-published data and should be treated as design benchmarks rather than specification limits. Finished part performance depends on mold geometry, cooling rate, wall thickness distribution, and post-mold storage temperature.
| Property | Test method | Typical value |
|---|---|---|
| Density | ASTM D1505 | 0.953 g/cm³ |
| Melt flow index | ASTM D1238, 190°C/2.16 kg | 0.20 g/10 min |
| Tensile yield strength | ASTM D638 | 28 MPa |
| Tensile elongation at break | ASTM D638 | >600% |
| Flexural modulus | ASTM D790 | 1310 MPa |
| Environmental stress crack resistance, F50, Condition B, 100% Igepal | ASTM D1693 | >600 h |
| Vicat softening point | ASTM D1525 | 127°C |
| Brittleness temperature | ASTM D746 | < -75°C |
| Shore D hardness | ASTM D2240 | 66 |
When wall thickness is reduced below 0.8 mm, the effective modulus of a blow molded article can deviate from test plaque values, and ESCR becomes more sensitive to internal surface defects, die lip deposits, and mold temperature variation. Published data for this specific configuration in thin-wall barrier structures is limited, and part-level ESCR, drop impact, and top-load testing are required before direct substitution into tools originally qualified for higher-melt-index resins.
When aggressive liquid packaging demands sustained ESCR retention
Aggressive liquid packaging applications rely on the combination of 0.953 g/cm³ density, 1310 MPa flexural modulus, and an ESCR F50 above 600 h under ASTM D1693 Condition B in 100% Igepal. The grade is therefore used for surfactant-based cleaners, agricultural emulsifiable concentrates, and mild oxidative formulations. The performance boundary is not unlimited. Strong oxidizing acids, aromatic hydrocarbons, and halogenated solvents can stress-crack or soften HDPE, especially at continuous fill temperatures above 40°C. Compatibility trials should include chemical storage at maximum fill temperature, followed by drop impact testing per ASTM D2463 and compression after aging per ASTM D2659. For permeation-limited applications, barrier testing should be conducted on the actual container geometry, because wall thickness and surface-to-volume ratio change the permeation rate.
ESCR test variability is significant. ASTM D1693 Condition B F50 values are intrinsically variable; duplicate values can differ by ±20% even within a single lot. The F50 value above 600 h should therefore be treated as a ranking tool rather than an absolute service-life prediction. Field experience with HDPE detergent containers shows that failure occurs preferentially at pinch-off weld lines or molded-in handle attachment points, where localized stress concentration is highest. Mold design features such as generous radii at the pinch-off insert and uniform parison thickness reduce the apparent ESCR advantage of high-density grades.
Thermal analysis by differential scanning calorimetry indicates that HDPE of 0.953 g/cm³ density typically exhibits a peak melting temperature near 134°C and a crystallization peak near 117°C at a cooling rate of 10°C/min. These transitions affect mold temperature requirements and dimensional stabilization after demolding. Parts ejected at surface temperatures above 70°C may continue to shrink unevenly; forced cooling and post-mold fixturing are common for containers with flat panel sections.
In relation to other polyolefins, DMDA-6200 NT7 occupies a denser, stiffer position than low-density polyethylene squeezable bottle grades, which usually range from 0.915 g/cm³ to 0.925 g/cm³. It also differs from impact-modified polypropylene, which has lower density but higher upper service temperature and different ESCR behavior in surfactant environments. These comparisons matter when a converter is considering downgauging from HDPE to LDPE for added flexibility or switching to polypropylene for hot-fill resistance; each substitution requires revalidation of top-load, drop impact, and environmental stress crack resistance under the target distribution cycle.
Regulatory alignment for DMDA-6200 NT7 is generally established within polyolefin food-contact provisions. The grade is handled under 21 CFR 177.1520, EU Regulation (EC) No 1935/2004, and EU Regulation (EU) No 10/2011; specific migration must be confirmed on the finished container. The following matrix summarizes the principal regulatory frameworks encountered in container production.
| Regulatory framework | Relevant scope |
|---|---|
| 21 CFR 177.1520 | Olefin polymers for food contact, subject to limitations and migration testing |
| EU Regulation (EU) No 10/2011 | Plastic food-contact materials, overall migration limit 10 mg/dm² |
| EU Regulation (EC) No 1935/2004 | Framework regulation for food-contact materials |
| REACH Regulation (EC) No 1907/2006 | Substances of very high concern, authorization and restriction |
| RoHS Directive 2011/65/EU | Restricted substances in electrical and electronic equipment |
The unpigmented natural resin has limited ultraviolet resistance and is not recommended for direct outdoor exposure without additional UV stabilization. Peroxide-initiated or strongly acid-functional adhesive systems should be avoided unless peel strength and environmental aging data are generated for the specific multilayer structure. Warehouse storage at temperatures below 0°C does not harm the resin, but condensed moisture from temperature cycling can carry surface dust into the hopper, increasing gel-like defects. Silos and hoppers should include magnet drawers and bypass filtration screens of 60 to 100 mesh to protect die lip surfaces. Regrind from trimmed flash and rejected containers may be incorporated at levels typically up to 20% in non-food applications if the process is stabilized; higher regrind levels increase the risk of gel formation and reduced ESCR due to shear history.
