InnoPlus LLDPE LL7420D is a linear low-density polyethylene film resin produced by PTT Global Chemical Public Company Limited. The material is a butene-copolymer LLDPE with a nominal density of 0.918 g/cm³ when tested under ASTM D1505 and a melt flow rate of 2.0 g/10 min at 190 °C/2.16 kg according to ASTM D1238. The resin is supplied as free-flowing pellets and is intended for blown film and cast film structures in which a controlled balance of impact strength, tear resistance, and optical clarity is required. Typical downstream uses include general-purpose packaging, lamination film, agricultural film, overwrap, and sealant layers. Published datasheet values are lot-representative targets, and actual certificate-of-analysis results may vary within the supplier’s specification band.

What Specification Set Should Guide Film Design Calculations?

The following table reproduces representative values from supplier technical literature for film-grade LL7420D. The mechanical and optical data are direction-dependent and are influenced by film gauge, blow-up ratio, die gap, frost line height, and cooling configuration. Values obtained on a 50 μm blown film may not transfer directly to thinner cast film or lamination layers without recalculation.

On a molecular level, InnoPlus LLDPE LL7420D is a linear copolymer with short-chain branches introduced by the butene comonomer. Unlike high-pressure low-density polyethylene, which contains long-chain branches and a broader molecular weight distribution from autoclave or tubular polymerization, this linear architecture reduces melt strength while increasing drawdown and dart impact at equivalent density. The difference is most evident in blown film bubble stability: LL7420D requires more controlled internal bubble pressure than LDPE because its extensional viscosity does not strain-harden to the same extent. Compared with hexene or octene LLDPE copolymers, the butene architecture generally produces lower dart impact and puncture resistance at equal density and melt flow rate, but the material offers a cost-effective balance for applications that do not require maximum toughness.

The D suffix within the LL7420 series is associated with a formulated additive package intended for slip and antiblock performance. The exact additive composition is proprietary to the supplier. The effect of the surface package becomes measurable as a reduction in film-to-film blocking force and a controlled coefficient of friction after migration has reached equilibrium. This migration kinetics are film-gauge dependent and are accelerated by storage temperature. Converters should not infer a single coefficient-of-friction value from the resin data sheet alone, because the final value depends on film thickness, maturation time, corona treatment, and lamination or printing conditions.

Blown Film Die Gap and Bubble Cooling Parameters

Processing of InnoPlus LLDPE LL7420D on blown film lines is constrained by the relationship among die gap, melt temperature, and frost line height. Published processing guidance for 2.0 g/10 min C4-LLDPE film grades indicates that die gaps below 1.5 mm can initiate sharkskin melt fracture at high shear rates. Increasing the die temperature toward the upper end of the 190 °C to 210 °C range may reduce the defect, but the adjustment must not exceed the stabilizer’s thermal boundary. Die gaps above 2.5 mm reduce shear and molecular orientation, yielding films with lower machine-direction tear and higher transverse-direction tear. A single-lip air ring with a frost line height of 8 to 12 times the die diameter is commonly used for LLDPE film grades, but the bubble must be stabilized by internal bubble cooling when throughput exceeds approximately 200 kg/h on large production lines. Published data for LL7420D on specific extrusion lines is limited; therefore, the operating window must be established from screw design, die diameter, and haul-off speed.

Compared with LDPE, LL7420D exhibits lower melt strength and higher shear viscosity at equivalent melt index. This combination increases extruder torque and die pressure in conventional smooth-bore single-screw extruders. A barrier screw with an L/D of 30:1 or a grooved-feed extruder designed for LLDPE is typically required to maintain melt quality at high output. Melt temperature should be controlled between 180 °C and 220 °C. Temperatures above 230 °C can accelerate antioxidant depletion and contribute to gel formation, while temperatures below 170 °C can produce unmelts at high screw speed. On cast film lines, the linear architecture permits higher line speeds but can produce draw resonance if the air gap is too long or if melt temperature is insufficient.

Cast film lines impose a narrower melt temperature envelope

On cast film equipment, the melt temperature window for LL7420D is often narrower than on blown film lines because the polymer curtain must remain stable from the flat die to the chill roll. A melt temperature of 190 °C to 215 °C is commonly used for C4-LLDPE cast film when the die gap is set between 0.8 mm and 1.2 mm. The air gap is typically kept below 10 cm to prevent neck-in and edge instability. Chill roll temperatures in the range of 20 °C to 40 °C are used to control crystallization and reduce blocking. If the resin contains the D-variant slip/antiblock package, the chill roll surface must be maintained clean because additive migration can produce a visible film at high roll temperatures over extended running periods. Vacuum box or electrostatic pinning is required above a critical line speed, which depends on the die width and film gauge.

Food-contact film structures use InnoPlus LLDPE LL7420D in sealant or core layers. Compliance statements for food contact in the United States are typically based on FDA 21 CFR 177.1520, and EU food contact is assessed under Regulation (EU) No 10/2011 with overall migration limits specified in the regulation. The resin is not formulated for medical implant or parenteral use. Converters must verify organoleptic and migration performance on the finished structure because printing inks, tie layers, and barrier polymers contribute to the final compliance profile. For agricultural greenhouse film, the grade is compounded with a UV stabilizer masterbatch, typically based on hindered amine light stabilizer chemistry and a broad-band UV absorber. The addition level is determined by accelerated weathering under ISO 4892-2 or ASTM G154 rather than by resin specification alone.

The resin is not hygroscopic, and pre-drying is not normally required. However, condensation on cold pellets introduced into a hot extruder can create surface splay and reduce film quality. Storing the resin below 60% relative humidity and allowing cold pellets to reach ambient temperature before opening silo or bag discharge is recommended in high-humidity production environments. The melt is incompatible with unneutralized high-acid polymers such as acrylic acid copolymers and ionomers; incorporation of these materials into reclaim streams can create gels and optical defects. Reclaim containing EVOH barrier layers should be used only with a functional tie layer in the film structure, since direct dispersion of EVOH in LLDPE can cause visible gel formation and loss of dart impact.

When InnoPlus LL7420D Replaces a C6-LLDPE or LDPE Grade in Lamination Layers

Substitution of LL7420D for a hexene-copolymer LLDPE in cast stretch film or lamination layers changes the balance of dart impact, puncture resistance, and stretch force. Butene-copolymer LLDPE generally exhibits lower dart impact and tear resistance than hexene or octene copolymers at equal density and melt flow rate. Published data for direct property comparisons between LL7420D and specific C6 grades is limited; the substitution therefore requires a pilot trial to establish whether the required on-pallet load retention and puncture tolerance are maintained. In lamination films, the lower melt strength of LL7420D relative to LDPE may require adjustment of the air gap or addition of 10% to 20% LDPE to stabilize the melt curtain. The addition of LDPE also raises haze and reduces dart impact, so the blend ratio must be optimized against the end-use optical specification.

In blown film, the butene architecture of LL7420D yields lower clarity than mLLDPE but provides better processability, lower melt pressure, and less draw resonance tendency than metallocene grades. Selection of LL7420D over a metallocene LLDPE is therefore driven by cost-to-performance ratio, extruder compatibility, and bubble stability rather than by optical ceiling. In applications where seal initiation temperature is the controlling variable, mLLDPE or a C6-LLDPE with lower seal initiation may be preferred. In high-clarity overwrap, LL7420D is usually blended with LDPE or mLLDPE to reduce haze while retaining the processability of the butene copolymer.

InnoPlus LLDPE LL7420D is not designed for rotational molding or injection molding; those processes require different melt flow and density ranges. The grade is also not recommended for direct exposure to strong oxidizing agents, chlorinated solvents, or aromatic hydrocarbons at elevated temperatures without chemical compatibility testing. The operational boundary for continuous use in food packaging is set by the migration limits of the finished structure under Regulation (EU) No 10/2011 and FDA 21 CFR 177.1520, not by the resin’s thermal resistance alone. Converters running high-speed form-fill-seal equipment should verify that the slip/antiblock package reaches equilibrium film-to-film friction values before setting film tension, because friction changes during the first 72 h of maturation can affect reel formation and downstream tracking.