The trade designation LDPE 2102TX00 and 2100TN00: Heavy-Duty Film Grades in Trade identifies two high-pressure low-density polyethylene homopolymers supplied as pelletized film-extrusion resins. The nominal density for both grades is 0.921 g/cm³ when tested under ISO 1183-1:2019. The melt flow rates differ significantly: 2100TN00 is typically 1.0 g/10 min and 2102TX00 is typically 1.9 g/10 min at 190 °C/2.16 kg under ISO 1133-1:2022. This difference is the dominant variable for processing machinery setup, film toughness, and end-use selection. Both grades belong to the high-pressure tubular or autoclave LDPE family and exhibit broad molecular weight distribution with high molecular weight tails that support bubble stability. The 2100TN00 grade is the lower-melt-flow member and is used where thicker film and higher puncture resistance control the application; the 2102TX00 grade is used where lower extrusion pressure and higher throughput are required.

How Do Melt Flow Rate and Molecular Architecture Separate the Two Blown-Film Grades?

The melt flow rate of 1.0 g/10 min for 2100TN00 corresponds to higher average molecular weight and longer stress relaxation times relative to the 1.9 g/10 min of 2102TX00. In blown-film extrusion, this changes melt viscosity, die pressure, and bubble configuration. On a 60 mm single-screw extruder with a 28:1 L/D barrier screw, melt pressure measured before the screen changer typically increases by 15–25% when 2100TN00 replaces 2102TX00 at identical screw speed and barrel settings. The higher melt strength permits 2100TN00 to sustain a stable bubble at blow-up ratios of 2.0:1 to 3.5:1 and frost line heights from 800 mm to 1200 mm. The 2102TX00 grade is more shear-thinning at process shear rates and can be run at melt temperatures of 165–180 °C, whereas 2100TN00 generally requires 175–190 °C to avoid melt fracture and excessive back pressure. The broad molecular weight distribution of high-pressure LDPE, typically Mw/Mn 6–12, provides the shear thinning required for both grades; however, 2100TN00 retains more extensional viscosity, which is the key parameter for bubble stability in thick-film production.

On production-scale blown-film lines, 2100TN00 is commonly processed with die gaps from 1.2 mm to 2.2 mm for films from 80 µm to 150 µm. Automatic air-ring control and internal bubble cooling are used to keep gauge variation at ±5%; manual air-ring lines may show ±8% variation. If the die gap is reduced below 1.0 mm, the high viscosity of 2100TN00 can produce shark-skin melt fracture at the die lip, visible as surface roughness. Melt temperatures above 200 °C should be avoided for both grades because prolonged residence time at elevated temperature accelerates oxidative gel formation and black-spec contamination. Purging after shutdown should be carried out with a lower-viscosity LDPE or purge compound at 160–180 °C. LDPE is non-hygroscopic, but when pellets are transferred from a cold warehouse to a production floor with relative humidity above 60%, surface condensation may form; a hopper dryer at 60 °C for 0.5–1 h is recommended before extrusion.

When 2100TN00 Is Preferred over 2102TX00 in Heavy-Duty Sack Lines

Heavy-duty open-mouth sacks, form-fill-seal packaging, construction films, and agricultural silage films above 70 µm thickness are the principal application fields for 2100TN00. The lower melt flow produces higher dart drop impact and greater slow puncture resistance at equal film thickness. In FFS lines filling 25 kg or 50 kg loads, the outer ply is frequently produced from 2100TN00 to improve drop impact and tear propagation resistance, while 2102TX00 may be used as the inner sealing ply because it initiates heat seal at lower temperature. Seal initiation for 2102TX00 is typically 95–105 °C at 0.5 N/mm² jaw pressure, while 2100TN00 may require 105–115 °C under the same conditions. The difference is caused by slower chain diffusion in the higher-molecular-weight grade. For monolayer FFS films, converters adjust jaw temperature and dwell time to reach a minimum seal strength of 3 N/25 mm before the filled sack enters the drop-test station. For agricultural silage wrap and cover films in the 100–150 µm range, 2100TN00 is specified for puncture resistance after field flexing. For thin liners below 40 µm, 2102TX00 usually permits higher line speed and lower melt pressure.

Comparative film-property ranges are shown in Table 1 for a 50 µm monolayer blown film produced at a blow-up ratio of 2.5:1, melt temperature 180 °C, and die gap 1.8 mm.

These values are representative ranges from commercial film-grade data and laboratory blown-film lines; production results can shift by 10–20% depending on frost line height, die diameter, winder tension, and additive masterbatch loading. Published data for these exact trade designations in some end-use configurations is limited; the ranges shown are representative for high-pressure LDPE film grades with equivalent melt flow and density and should be verified against the supplier certificate of analysis. If 2100TN00 film is quenched too rapidly, the dart drop impact can fall below 120 g because frozen-in orientation reduces energy absorption. Conversely, 2102TX00 film produced with a high blow-up ratio and low frost line may develop MD/TD tensile anisotropy above 1.4:1, which contributes to gusset-tearing in shaped sacks. Filled-bag drop testing for heavy-duty sacks is commonly performed under ISO 7965-1; typical acceptance criteria require no bag failure after a 1.2 m flat drop on the face and 0.8 m on the edge for a 25 kg load. The elongation at break and dart drop impact values should be used together because elongation alone does not predict filled-bag performance.

Melt Pressure, Viscous Dissipation, and Gel Formation Limits

Extrusion of 2100TN00 in 150 µm geomembrane support films and heavy-duty sacks may generate die pressures of 32–40 MPa, while 2102TX00 at equivalent thickness may remain at 25–33 MPa. The higher pressure in 2100TN00 is converted to viscous heat, so the barrel temperature profile is usually set 5–10 °C lower in the compression section to prevent uncontrolled melt-temperature rise. Screen-pack selection follows the same logic: a 60/80/100 mesh pack is common for 2100TN00, whereas 2102TX00 can tolerate a finer 80/100/120 mesh pack without excessive pressure loss. The maximum practical melt temperature for both grades is 200 °C; above this threshold, oxidative degradation accelerates and gel particles appear on the film surface. Residence time at 180 °C should be limited to approximately 20 min during line stoppage because the high-molecular-weight tail in 2100TN00 is especially sensitive to chain scission and crosslinking under oxygen. Processors should monitor die pressure trend; a gradual rise at constant screw speed often indicates gel deposition in the die lip or degraded material in the screen changer. When the screen pack is not changed after the pressure increases by 20–25% from the clean-die baseline, the resulting gel contamination can compromise film tear resistance and printed-surface quality.

The additive package in these grades is not fully defined by the trade suffix alone; the converter should verify slip, antiblock, and antioxidant concentrations from the certificate of analysis. If the film must have a coefficient of friction below 0.25, erucamide slip masterbatch is typically added at 500–1,500 ppm active slip. Excessive slip above 2,000 ppm may bloom to the surface and reduce ink adhesion. Antiblock silica at 1,000–3,000 ppm lowers blocking in high-temperature storage but can reduce dart drop impact by 10–20% because silica particles act as stress concentrators. After corona treatment, film surface tension should reach 38–42 mN/m for solvent-based inks and 44–48 mN/m for water-based lamination, measured by ASTM D2578-09. Treated film loses 2–4 mN/m of surface tension within 30 days, so inline treatment immediately before printing is preferred. Both grades are incompatible with strong oxidizing acids, chlorinated solvents, and long-term direct sunlight unless stabilised with carbon black or hindered amine light stabilizers. Unstabilised LDPE film exposed outdoors in high-UV climates can lose more than 50% of its original elongation at break within 6 months. Pellets should be stored below 40 °C and consumed within 6 months of opening to limit oxidative degradation.

In coextruded heavy-duty sack structures, 2100TN00 is placed in the core or outer layer to provide slow puncture resistance, while 2102TX00 is used in the sealing layer. On FFS lines producing 50–70 µm sacks, this combination permits high sealing speed and reduces edge-weld failures. The 2100TN00 outer layer increases dart drop impact by 15–25% compared with an all-2102TX00 structure, while the 2102TX00 sealing layer maintains hot-tack strength above 3 N/25 mm during the fill-and-seal cycle.