Dow HDPE DMDC-6143 NT 7
- Product Name: Dow HDPE DMDC-6143 NT 7
- Factroy Site: Yinchuan, Ningxia, China
- Price Inquiry: sales8@ascent-chem.com
- Manufacturer: Ascent Petrochem Holdings Co., Limited
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- Dow HDPE DMDC-6143 NT 7 is typically used in formulations when melt flow index and density and processing temperature and pressure must be controlled within specific ranges.
| HS Code | 245382 |
| Density | 0.943 g/cm³ |
| Melt Index 190 C 2 16 Kg | 0.25 g/10 min |
| Melting Point | 131 °C |
| Vicat Softening Point | 124 °C |
| Tensile Strength At Yield | 24 MPa |
| Tensile Strength At Break | 30 MPa |
| Elongation At Break | 600% |
| Flexural Modulus | 1100 MPa |
| Environmental Stress Crack Resistance 10 Igepal | >1000 h |
| Hardness Shore D | 65 |
As an accredited Dow HDPE DMDC-6143 NT 7 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Dow HDPE DMDC-6143 NT 7 is packaged in 25 kg moisture-resistant polyethylene bags; bulk quantities available in 1,000 kg bags. |
| Container Loading (20′ FCL) | Dow HDPE DMDC-6143 NT 7 loaded in a 20′ FCL container, palletized bags, securely stowed and sealed for ocean transport. |
| Shipping | Dow HDPE DMDC-6143 NT 7 is a non-hazardous, solid high-density polyethylene resin. It is typically shipped in 25 kg bags, octabins, or bulk trucks/railcars. Not regulated for transport. Keep dry, avoid ignition sources, and store in a cool, ventilated area. Follow SDS/local rules and use appropriate PPE. |
| Storage | Store Dow HDPE DMDC-6143 NT 7 indoors in a cool, dry, well-ventilated area, away from direct sunlight, heat, sparks, flames, and strong oxidizers. Keep original containers or bags tightly closed on pallets, off the floor, to prevent moisture, dust, and contamination. Avoid prolonged UV exposure; use first-in, first-out rotation and follow the SDS. |
| Shelf Life | No defined shelf life; store in original packaging under cool, dry conditions, away from direct sunlight and heat. |
Dow HDPE DMDC-6143 NT 7 enters conversion operations as a natural-pellet high-density polyethylene. Under ISO 1133-1:2022 at 190 °C/2.16 kg, the melt flow rate is specified by the lot certificate; typical values for this low-sag blow-moulding and sheet grade fall in the 0.6–1.0 g/10 min range. Density measured under ISO 1183-1:2019 is in the 0.942–0.946 g/cm³ range. The resin does not require routine drying; if ambient humidity exceeds 60 %, surface condensation is removed in a dehumidifying hopper at 80 °C for 2 h. The resulting melt is used in applications where melt extensibility, environmental stress crack resistance, pinch-off weld integrity, and sheet sag behaviour are primary end-use constraints. Lot-to-lot melt flow variation of ±0.1 g/10 min should be expected across production campaigns without changing the material designation.
When Extrusion Blow Moulding Industrial Chemical Containers Demands Predictable Pinch-Off Weld Integrity
On shuttle blow moulders with 22:1 to 30:1 L/D extruders, the grade processes in barrel zones between 170 °C and 195 °C, with die head temperature held at 195–205 °C and melt temperature not exceeding 215 °C. The setpoint table below is a starting reference for a 25 kg container with 2.0–2.5 mm minimum wall. On a 65 mm extruder with a 24:1 L/D barrier screw, die pressure is normally 20–35 MPa; pressure variation greater than ±1.5 MPa over 30 min indicates feed bridging or worn screw clearances. Screw speed is set between 30–50 rpm for a 25 kg container cycle. The pinch-off weld is a folded, heat-compressed region; failure at this location is governed by mould closing speed, melt temperature, and flash trim geometry. Closing the mould too slowly at the pinch edge—below 0.3 m/s linear edge speed—allows crystallization before sufficient reentanglement, producing a low-strength seam. The seam is tested by ISO 6603-2 dart impact at -20 °C; penetration energy below 20 J at 2 mm thickness indicates brittle pinch-off behaviour. The finished drum or jerrican is subjected to ASTM D1693 environmental stress crack resistance testing in 10 % Igepal CO-630 at 50 °C. The F50 value is taken from the lot certificate; if the F50 value is lower than the plant’s internal limit for the intended chemical class, wall thickness should be increased by 0.5 mm rather than raising die head temperature above 210 °C. Processing above 220 °C produces carbonyl thermo-oxidation species that suppress ESCR and generate yellowing measurable as a b* shift above 3 units under ASTM E313. Regrind from flash and rejected parts is incorporated at 20–30 wt%; higher regrind fractions reduce weld strength and widen lot-to-lot variability. The terminal article is an industrial drum or jerrican for non-food chemicals, labelled according to ADR/RID and IMDG Code where applicable.
| Parameter | Setpoint or range | Checkpoint |
|---|---|---|
| Feed throat | 40–60 °C | No pellet melting in throat |
| Barrel zone 1 | 170–180 °C | Melt pressure stability |
| Barrel zone 2 | 180–190 °C | Screw load fluctuation |
| Barrel zone 3 | 190–195 °C | Melt temperature gradient |
| Die head/adapter | 195–205 °C | No die-lip plate-out |
| Melt temperature | 195–210 °C | Insertion probe reading |
| Mould water | 12–18 °C | Part surface freeze rate |
| Blow air pressure | 0.7–0.9 MPa | Pinch-off flash thickness |
| Regrind addition | 20–30 wt% | Weld impact retention |
Because crop-protection formulations vary from hydrocarbon solvents to aqueous emulsions, the same blow-moulded jerrican is required to pass UN Model Regulations Chapter 6.1 for packaging group II. In this application, the wall-thickness programme must place additional material in the handle and lower pinch-off zones; a handle wall below 1.8 mm combined with a label panel of 1.2 mm creates a flexural hinge that reduces service life under ASTM D1693. The resin is run with 0.15–0.30 wt% hindered phenolic antioxidant masterbatch, 0.05–0.10 wt% phosphite stabilizer, and 2–4 wt% color concentrate. Carrying-agent loadings above 0.50 wt% cause die-lip plate-out on 8 h runs. Mould water at 12–18 °C is held to minimize coarse spherulite growth at the pinch-off. The terminal article is a 10–20 L UN-marked jerrican; the marking is moulded into the sidewall and includes the UN symbol, rigid plastics code, packaging group, and test pressure. The hydraulic pressure test is run at 100 kPa for 30 min for ordinary liquids; a wall-thickness variation coefficient above 5 % causes localized yield at the handle root.
What Limits Drop Test Throughput for UN-Rated Agricultural Chemical Jerricans?
After the drop-test protocol has been fixed at -18 °C for liquids with a flash point below 60 °C, throughput is limited not by the extruder but by the gelation time at the pinch-off weld. Cooling water at 12 °C produces demouldable weld strength in 22–28 s for a 10 L jerrican with a 2.3 mm nominal wall; water at 25 °C extends this to 35–45 s. Cycles below 20 s produce a coarse spherulitic seam and cold drop failure instead of stress-whitening. The relevant sequence is conditioning for 24 h at 23 °C/50 % RH, cooling for 4 h at -18 °C, and a 1.2 m drop onto a concrete puncture plate. A leak after 5 min constitutes a UN failure; non-leaking cracks are internal rejects. Table 2 provides the compliance checklist used on this container class. Accumulator-head parison droop must remain below 10 % of total parison length; droop above this value shifts the lower wall above 3.5 mm and lengthens cycle time without improving weld impact. The terminal article is a stackable 10 L crop-protection jerrican tested for stacking at 45 °C for 28 days under ISO 2234; permanent deflection above 3 mm is grounds for rejection.
| Test discipline | Standard/regulation | Condition | Pass criterion |
|---|---|---|---|
| Drop | UN 6.1.5.3 | -18 °C, 1.2 m | No leak after 5 min |
| Hydraulic pressure | UN 6.1.5.5 | 100 kPa, 30 min | No leakage |
| Stacking | ISO 2234 | 45 °C, 28 days | Deflection < 3 mm |
| ESCR | ASTM D1693 | 10 % Igepal CO-630, 50 °C | Lot certificate F50 > plant limit |
| Impact | ISO 6603-2 | -20 °C, 2 mm coupon | Penetration energy > 20 J |
Automotive fluid reservoir trials place DMDC-6143 NT 7 as the structural HDPE layer in a 3-layer or 6-layer coextruded parison. The weight composition is normally 85–90 wt% HDPE substrate, 5–8 wt% ethylene-maleic anhydride tie resin, and 3–5 wt% polyamide or EVOH barrier. The HDPE layer is maintained below 215 °C, while the tie layer requires 210–230 °C; a die-temperature offset above 2 °C between adjacent layers produces interface waviness measured as a gloss variation greater than 10 % under ISO 2813. The finished part is a washer fluid bottle, coolant expansion tank, or SCR feed reservoir. Automotive validation includes temperature cycling under ISO 16750-4 from -40 °C to 105 °C and vacuum leak testing under ASTM D3078 at 2 kPa for 60 s. Because published O₂ permeation data for this specific coextruded configuration is limited, the finished reservoir must be tested under ASTM D3985 at 40 °C; the barrier layer cannot be assumed continuous from layer ratios alone. The resin’s ESCR is relevant for coolant containing 50 % ethylene glycol at 90 °C, but unfilled HDPE is not qualified for methanol-containing electrolytes without long-term immersion data under ASTM D543. Regrind is limited to 20 wt% in the barrier structure; higher regrind raises the likelihood of barrier-layer pinholes and reduces SAE J1684 cycle-life performance.
Sheet Thermoforming: Sag Rate and Cooling Rate in High-Modulus Industrial Dunnage
In sheet thermoforming, sag rate and cooling rate control cycle time more than parison wall distribution. The grade is extruded on a 120 mm single-screw line with a 30:1 L/D barrel and a flat die lip gap of 3–4 mm. Forward barrel temperatures from 180 °C to 200 °C produce a sheet melt surface temperature near 205 °C at the roll stack; polished rolls are held at 80–95 °C. Above 100 °C, the sheet surface remains tacky and wraps the lower roll. For forming, sheet is heated to 135–150 °C using 300–350 °C ceramic heaters; the sag rate across a 120 mm free span should remain below 12 mm/s. Matched aluminium tooling at 60–80 °C forms the part, and cooling time dominates because HDPE crystallizes over a broad interval around 118–120 °C. The terminal article is a thermoformed dunnage tray, pallet separator, or nesting tote. Static load capacity is evaluated under ASTM D642 at 23 °C and 45 °C; a 4 mm, 1 m² tray can typically carry 500 kg for 24 h with less than 10 % deflection at 23 °C, though production designs must be prototyped. Regrind at 20–30 wt% is standard; above 30 wt%, ESCR under ASTM D1693 declines and gloss uniformity decreases after repeated heat histories. The die gap and roll differential must be set so that machine-direction and transverse-direction shrinkage measured under ISO 11501 at 120 °C differ by less than 0.5 %; asymmetry above this level causes formed parts to bow after trimming.
When the converter shifts from UN-rated jerricans to household detergent bottles, the limiting variable is not parison sag but additive migration to the neck surface. The terminal article is a 1–5 L bottle with 1.0–1.6 mm wall and a 38 mm or 45 mm bore closure. The material is processed with 0.10–0.20 wt% erucamide slip masterbatch; addition above 0.30 wt% lowers screw-cap removal torque to below 1.5 N·m and promotes stress cracking at the shoulder under 7-day exposure to linear alkylbenzene sulfonate at 40 °C. Free amine-bearing additives are avoided because they deactivate the acidic stabilizer package and aggravate die-lip deposit. The die gap is 1.2–2.0 mm and blow pressure is 0.6–0.8 MPa. Shoulder coupons are tested under ASTM D256 at -20 °C; values below 8 kJ/m² indicate cold melt or insufficient reentanglement. The finished bottle is compliant with REACH and, for incidental food-contact evaluations, EU 10/2011; it is not a UN-rated container unless additional wall-thickness and closure certification are applied.
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- Dow HDPE DMDC-6143 NT 7 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 DMDC-6143 NT 7 is supplied as a natural-color, high-density polyethylene injection molding resin. The grade is a linear polyethylene homopolymer with a narrow molecular weight distribution, and the NT 7 designation identifies the natural pellet form with the standard stabilizer package. Nominal physical properties are as follows: density 0.958 g/cm³ by ASTM D792 or ISO 1183-1; melt flow rate 0.85 g/10 min at 190 °C and 2.16 kg by ASTM D1238 or ISO 1133-1; tensile yield strength 28 MPa by ASTM D638; flexural modulus 1.20 GPa by ISO 178; notched Izod impact strength 5 kJ/m² at 23 °C by ISO 180/A; and Vicat softening temperature 126 °C by ASTM D1525. These values are nominal and are not specification limits; lot-level release data on the manufacturer’s certificate of analysis governs acceptance. The resin is intended for rigid injection molded articles in which stiffness, dimensional consistency, and moderate impact resistance are the primary design requirements.
How Does Narrow Molecular Weight Distribution Influence Filling and Solidification?
The narrow molecular weight distribution of DMDC-6143 NT 7 reduces the breadth of the shear-thinning response during cavity filling. At equivalent melt flow rate, a narrow-distribution polyethylene exhibits a more Newtonian viscosity profile than a broad-distribution blow molding grade, meaning that viscosity remains less sensitive to increasing shear rate. This behavior produces predictable filling patterns in relatively thick sections, but it can raise the pressure required to fill long flow paths or thin ribs. Molders should expect the effective flow-length-to-wall-thickness ratio to be more pressure-limited than with a broad-molecular-weight resin of identical nominal melt flow. Solidification behavior is governed by the 0.958 g/cm³ density and the linear homopolymer backbone. Shrinkage is anisotropic, with mold shrinkage typically measured in the range of 1.5% to 2.5% by ASTM D955 depending on wall thickness, gate geometry, packing pressure, and mold temperature. Differential shrinkage between flow and transverse directions is a primary cause of warpage in flat industrial parts such as dunnage trays and container lids.
On a typical hydraulic injection molding machine, the screw should be a general-purpose HDPE configuration with L/D of 20:1 to 24:1 and a compression ratio between 2.5:1 and 3.0:1. Non-return valve clearance should be maintained below 0.05 mm; excessive clearance produces cushion loss, short shots, and inconsistent packing pressure. The following table lists typical starting conditions for injection molding this grade. These values are general HDPE processing ranges and must be optimized against part geometry, gate size, runner balance, and machine capacity.
| Processing parameter | Typical range | Unit |
|---|---|---|
| Melt temperature | 210–260 | °C |
| Mold temperature | 15–30 | °C |
| Injection pressure | 60–100 | MPa |
| Holding pressure | 50–70 | MPa |
| Back pressure | 0.5–1.5 | MPa |
| Screw surface speed | 80–120 | rpm |
| Maximum residence time at melt temperature | below 5 | min |
Melt temperature above 260 °C or residence time beyond 5 min increases the risk of molecular weight breakdown, yellowing, and loss of impact resistance. Although HDPE is not hygroscopic, surface condensation from cold pellet storage can introduce moisture that appears as silver streaks; if pellets have been stored below 10 °C and then exposed to ambient air with relative humidity above 60%, pre-drying in a hot-air dryer at 60 °C to 80 °C for 2 h to 4 h is sufficient. A desiccant dryer is not required because moisture uptake is limited to surface adsorption.
Comparative Property Boundaries Against Blow Molding and High-Flow Injection Grades
DMDC-6143 NT 7 differs from blow molding grades in molecular weight distribution, melt strength, and die swell. A representative blow molding grade such as Dow HDPE DMDA-8007 NT 7 carries a nominal density near 0.965 g/cm³ and a nominal melt flow rate near 0.8 g/10 min, but its broader molecular weight distribution and higher molecular weight fractions are specifically designed for parison stability, sag resistance, and die swell. DMDC-6143 NT 7 is not optimized for those requirements. In blow molding, the parison must support its own weight during extrusion and inflation; in injection molding, the melt must fill a closed cavity under pressure and freeze rapidly after packing. Replacing a blow molding grade with DMDC-6143 NT 7 in a continuous extrusion blow molding line would produce insufficient die swell, narrow parison diameter control, and reduced melt strength. Conversely, using a blow molding grade in a high-pressure injection mold can create excessive shear heating, variable cushion behavior, and longer cycle times because of the broader melting and crystallization range.
Compared with high-flow injection grades in the same product family, DMDC-6143 NT 7 has a lower melt flow rate of 0.85 g/10 min. High-flow injection grades with melt flow rates above 10 g/10 min are favored for thin-wall closures, caps, and multi-cavity tools in which filling pressure is the limiting constraint. Those grades sacrifice some stiffness and environmental stress crack resistance to achieve lower melt viscosity. DMDC-6143 NT 7 resides in a different operating window: melt viscosity is higher, filling pressure rises in thin sections, but the molded part typically retains better rigidity and better resistance to long-term load-bearing deformation. The choice between low-flow and high-flow injection grades should be based on wall thickness, flow length, gate count, and clamp force. For a part with a nominal wall thickness above 2 mm and a projected area requiring less than 4 kN/cm² of clamp force, DMDC-6143 NT 7 can be processed effectively. For wall sections below 1 mm, high-flow grades are generally required because the pressure drop across the cavity becomes the controlling variable.
The density of 0.958 g/cm³ also differentiates DMDC-6143 NT 7 from high-molecular-weight film grades and from lower-density polyethylene grades. Film-grade HDPE typically has density above 0.940 g/cm³ but is formulated for blown film bubble stability and tear resistance rather than injection mold filling. LDPE and LLDPE grades with densities below 0.930 g/cm³ provide flexibility and impact toughness but cannot match the flexural modulus of this resin. The flexural modulus of 1.20 GPa is the key property that separates DMDC-6143 NT 7 from flexible polyethylene grades; a part molded from a lower-density material would require thicker walls to achieve equivalent load-bearing stiffness.
Environmental stress crack resistance should not be assumed equivalent to high-molecular-weight blow molding grades. Although DMDC-6143 NT 7 is a high-density homopolymer with moderate ESCR, applications involving continuous contact with surfactants, alcohols, or aggressive chemical environments require a specific evaluation according to ASTM D1693 condition B or an end-use immersion test. Published data for this specific configuration in aggressive environments is limited; manufacturers and converters should qualify the article using representative stress levels and chemical exposure rather than relying on nominal resin data alone.
Regulatory status for food-contact applications falls under FDA 21 CFR 177.1520 for olefin polymers. Compliance is not a resin property alone; the finished article must be tested for extractives, migration, and end-use conditions of use. The resin may also be evaluated against EU food-contact framework regulation 1935/2004 and specific migration limits under EU 10/2011 when used in food-contact articles, provided that the final formulation, colorants, and processing aids do not introduce non-compliant substances. REACH registration obligations apply to the legal entity placing the resin on the EU market. RoHS directive 2011/65/EU restricts lead, cadmium, mercury, hexavalent chromium, and certain brominated flame retardants; the natural grade is not formulated with intentional additions of these substances, but recycled content or external colorant masterbatches may require separate verification.
When Converting from a Higher Melt Flow HDPE Grade in Thin-Walled Closure Molding
When a processor replaces a high-flow HDPE grade having a melt flow rate above 10 g/10 min with DMDC-6143 NT 7 in an existing thin-walled closure tool, the first process variable to rise is injection pressure. The difference in melt viscosity between a 0.85 g/10 min resin and a 12 g/10 min resin is substantial, and the pressure drop across a long runner or narrow gate becomes the limiting constraint. Gates sized for a high-flow grade may require enlargement, and runner diameters may need to be increased by 10% to 15% to maintain equivalent filling time. Short shots, sink marks, and gate blush are the typical failure modes seen on production equipment when gate and runner modifications are not made. The melt temperature should be raised within the allowable range to 240 °C to 260 °C to reduce viscosity, but this reduces cooling efficiency and may extend cycle time.
If the part is a thin-walled container intended for food contact, the reduction in melt flow rate may also affect wall-thickness distribution. The packing phase becomes more critical because the higher melt viscosity limits pressure transmission through the solidifying layer. Holding pressure should be increased in steps of 5 MPa to 10 MPa while monitoring part mass and dimensional stability. Clamp force requirements should be recalculated from the projected area; switching from a high-flow grade to DMDC-6143 NT 7 can raise the injection pressure requirement enough to exceed the clamp force capacity of smaller machines. A machine with less than 3 kN/cm² of clamp force may flash under the higher holding pressure needed to pack thick bosses or rim sections. Published data for this specific conversion scenario is limited, and the safe procedure is to begin with a reduced shot size and fill-only stage to establish the pressure-limited flow front before adding packing pressure.
