ExxonMobil Exceed XP mLLDPE XP 8656RK
- Product Name: ExxonMobil Exceed XP mLLDPE XP 8656RK
- Factroy Site: Yudu County, Ganzhou, Jiangxi, China
- Price Inquiry: sales8@ascent-chem.com
- Manufacturer: Ascent Petrochem Holdings Co., Limited
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- ExxonMobil Exceed XP mLLDPE XP 8656RK is typically used in formulations when melt index, density, and molecular weight distribution and extruder melt temperature, die pressure, and output rate must be controlled within specific ranges.
| HS Code | 818480 |
| Polymer Type | Metallocene linear low density polyethylene (mLLDPE) |
| Density | 0.916 g/cm³ |
| Melt Index 190 C 2 16 Kg | 0.50 g/10 min |
| Peak Melting Temperature | 119 °C |
| Vicat Softening Temperature | 93 °C |
| Tensile Strength At Yield | 9.7 MPa |
| Tensile Strength At Break | 31 MPa |
| Elongation At Break | 600 % |
| 1 Secant Modulus | 190 MPa |
| Dart Drop Impact | 300 g |
| Elmendorf Tear Strength Md | 250 g |
| Elmendorf Tear Strength Td | 400 g |
| Haze | 10 % |
| Gloss At 45 | 60 |
| Coefficient Of Friction | 0.20 |
As an accredited ExxonMobil Exceed XP mLLDPE XP 8656RK factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Supplied in 25 kg polyethylene bags, palletized in 1,000 kg loads for industrial handling and storage. |
| Container Loading (20′ FCL) | 20′ FCL container loading for ExxonMobil Exceed XP mLLDPE XP 8656RK, using standard export packaging, palletized and securely stowed for ocean transport. |
| Shipping | ExxonMobil Exceed XP mLLDPE XP 8656RK is shipped as non-hazardous solid polymer pellets in sealed 25 kg bags or bulk octabins. Keep dry, cool, and protected from contamination and direct sunlight. No UN hazard class; handle and store according to the SDS and local regulations. |
| Storage | Store ExxonMobil Exceed XP mLLDPE XP 8656RK in a dry, cool, well-ventilated warehouse, away from direct sunlight, heat, moisture, and ignition sources. Keep original bags sealed, palletized, off the floor, and protected from contamination. Avoid excessive stacking, inspect packaging regularly, and follow first-in-first-out stock rotation. |
| Shelf Life | Shelf life is typically two years from date of manufacture when stored in original packaging below 50°C, protected from sunlight and moisture. |
Because frozen food packaging demands seal integrity after prolonged vibration at -18 °C, ExxonMobil Exceed XP mLLDPE XP 8656RK is frequently split between the core and sealant skin on three-layer coextrusion blown film lines. The base resin exhibits a melt index of 0.5 g/10 min under ASTM D1238 at 190 °C/2.16 kg and a density of 0.916 g/cm³ under ASTM D792. A representative layer distribution is 20/60/20 percent by mass: the outer layer is a fractional-melt LDPE or HDPE/LDPE blend for back-side heat resistance, the core is 100 wt% 8656RK, and the seal layer is a 70/30 wt% dry blend of 8656RK with a lower-density mLLDPE. Die temperature is held at 204–216 °C with a 2.0 mm die gap and blow-up ratio 2.5–3.0; frost line height is maintained at 6–8 die diameters. On a 250 mm die with internal bubble cooling, output stability typically fails when melt temperature swings outside a ±5 °C band because the narrow molecular weight distribution of the ethylene-hexene mLLDPE reduces shear thinning and elevates die pressure. The terminal articles—frozen vegetable pillow packs, poultry bags, and seafood IQF liners—require dart impact testing per ASTM D1709 Method A and Elmendorf tear testing per ASTM D1922 before gauge reduction below 50 µm is approved, since machine-direction orientation at higher haul-off speeds can reduce tear energy in the frost line. Food-contact status is evaluated under FDA 21 CFR 177.1520(c) for olefin polymers and EU Regulation (EU) No 10/2011, with overall migration testing per EN 1186-1:2002 and specific migration testing under the intended simulant. No pre-drying is needed at ambient humidity below 65% RH; however, condensation from chilled warehouse returns must be avoided because surface moisture on pellets can generate micro-voids in the seal layer. Reclaimed material above 20 wt% in the seal skin is not recommended when seal strength at 95 °C is a specification, because contaminant-rich reclaim widens the seal temperature range and increases seal failure variability.
Why Is Seal Strength Retention in Liquid Pouches Tied to Metallocene Commoner Distribution?
Producing high-integrity liquid pouch sealant webs from 8656RK requires separating the seal-strength plateau from the hot-tack window. In laminations such as BOPET/adhesive/BOPA/adhesive/sealant film, the sealant web is a blown monolayer or coextruded film at 30–60 µm, with the skin containing 90–100 wt% 8656RK and 0–10 wt% processing LDPE. The narrow commoner distribution typical of metallocene catalysis permits a seal strength plateau when seal bar temperature is raised from 110 °C to 150 °C at 0.3 MPa bar pressure and 1.0 s dwell, measured per ASTM F88. The film does not require melt indices above 0.5 g/10 min to flow over seal contaminants, provided the nip is uniformly closed and the sealing jaws are aligned within 0.05 mm. The process uses a 50 mm barrier screw with L/D 30:1, screen pack 20/40/60/100 mesh, and die melt temperature 210–220 °C. Terminal products include 1–5 L liquid pouch refills and spouted pouches. Compliance for non-food aggressive liquids is governed by the converter-specific extractables protocol, while food-adjacent use requires FDA 21 CFR 177.1520(c) and EU Regulation (EU) No 10/2011 verification on the finished laminate. A known boundary is that continuous peelable seal behavior cannot be obtained with 8656RK alone; peelable constructions should blend with polybutene or a second sealant resin, but such blends can reduce the high-strength weld plateau required for drop resistance. Published data for this specific configuration is limited, but field experience indicates that the resin is best reserved for lock-up seals in non-peelable liquid pouches, while peelable structures should use a separate sealant formulation on a second extrusion line.
Heavy-Duty Sack Extrusion at High Back Pressure and Low Gel Sensitivity
High back pressure on heavy-duty sack and liner lines becomes evident when 8656RK is run at high concentration because the melt index of 0.5 g/10 min produces higher pressure drop across the screen pack and die than a conventional 1.0 g/10 min LLDPE. A representative formulation is 80 wt% 8656RK with 20 wt% LDPE having melt index 0.25–0.5 g/10 min; the blend is melted in a 75 mm grooved-feed extruder with L/D 30:1, Maddock mixing section, and die diameter 300 mm. Melt temperature is controlled at 210–225 °C, die gap 2.2 mm, and BUR 2.0–2.5. Internal bubble cooling with chilled air at 10–15 °C is required; without IBC, output rates above 180 kg/h on this die can produce unstable frost lines and low dart impact. Puncture resistance is evaluated by ASTM D5748, and creep resistance of filled sacks is assessed by ISO 2247 after filling with 25 kg bulk product. The terminal products—FIBC liners, chemical drum liners, and bulk frozen vegetable sacks—require weld strength testing per ASTM F88 and tear testing per ASTM D1922; for UN transport, the entire sack/liner composite must be certified under the applicable UN packaging code, not the polymer alone. High back pressure is the main processing bottleneck: older shallow-flight screws may reach barrel pressure above 420 bar before the desired output, and processing above 230 °C should be avoided because it increases gel formation and reduces impact. Reclaim from printed film should not exceed 15 wt% in the core layer without a melt filtration system capable of removing particles above 100 µm, because screen pack blinding becomes more frequent with the lower viscosity LDPE carrier phase.
| Application boundary | Regulatory reference | Mechanical test method | Critical process threshold |
|---|---|---|---|
| Frozen food packaging sealant films | FDA 21 CFR 177.1520(c); EU 10/2011 | ASTM D1709 Method A; ASTM D1922 | Die melt temperature 204–216 °C; frost line 6–8 die diameters |
| Liquid pouch sealant webs | FDA 21 CFR 177.1520(c) for food-adjacent structures; converter extractables protocol for non-food | ASTM F88; ASTM F1921 | Seal bar 110–150 °C at 0.3 MPa/1.0 s |
| Heavy-duty sack liners | UN packaging code for transport units; REACH SVHC | ASTM D5748; ISO 2247 | Melt temperature ≤ 230 °C; barrel pressure 420 bar upper limit |
| Agricultural silage films | REACH SVHC; national packaging waste legislation | ASTM D4329; ASTM D1922 | UV masterbatch ≤ 15 wt%; melt temperature 205–215 °C |
| Hot-fill lamination sealant web | FDA 21 CFR 177.1395 only for qualifying retort structures; EU 10/2011 | ASTM F88; ASTM F1921 | Hot-fill ≤ 90 °C for 30 min; retort > 121 °C excluded |
| Collation shrink film | Food-contact multipacks require FDA 21 CFR 177.1520(c) and salt-free additive pack | ASTM D2732; dart impact by ASTM D1709 | 8656RK ≤ 60 wt%; die melt temperature 210–225 °C |
Five-layer agricultural films designed for silage clamp covers and greenhouse cladding use 8656RK in the core and inside skin to resist repeated folding, hail impact, and UV oxidation. The recommended dry blend is 85–90 wt% 8656RK with 10–15 wt% polyethylene carrier-based HALS/UV absorber masterbatch; the exact masterbatch loading is dictated by the additive supplier’s target UV stabilizer concentration, typically requiring 3600–4200 ppm of hindered amine light stabilizer in the final film. The film is run at 120–180 µm on a five-layer line with die gap 2.0 mm, BUR 2.2–2.8, and melt temperature 205–215 °C. In greenhouse service, these structures must retain tensile elongation above 400% after 1500 h QUV-B exposure per ASTM D4329, but field verification under solar irradiance is required because QUV acceleration does not reproduce all thermal and pesticide contact stresses. A process limitation appears when UV masterbatch loading exceeds 15 wt%: die lip deposit and haze increase, and transverse direction tear resistance measured by ASTM D1922 can decline below the specified minimum. The end products include silage clamp sheets, greenhouse cladding, and low tunnels; these are not food-contact applications so FDA 21 CFR 177.1520(c) is not a relevant criterion, but the film must comply with REACH SVHC restrictions and national waste packaging regulations. In tropical greenhouses, pesticide sulfur vapor and chlorine-based cleaners can accelerate surface oxidation even with the stabilizer package; this requires a sacrificial acid-neutralizing layer, not additional mLLDPE content.
When 8656RK Is Placed Opposite BOPA in Hot-Fill Laminations, Seal Integrity Depends on Thermal History
A heat-sealable layer of 8656RK in hot-fill laminations is limited by thermal history: the resin can seal strongly at 110–150 °C but must not be used as the sole sealant in true retort pouches above 121 °C. A representative sealant film is a three-layer coextrusion with 60 wt% 8656RK in the seal skin, 30 wt% low-density polyethylene in the core, and 10 wt% tie resin in the outer layer, with total gauge 40–70 µm. The film is cast at die temperature 210–220 °C, then laminated with a solventless two-part polyurethane adhesive at 40–50 °C nipping temperature and 0.3–0.5 MPa nip pressure, followed by 48 h room-temperature cure. Packages are evaluated under ASTM F88 for seal strength and ASTM F1921 for hot-tack; the hot-tack window of 8656RK is generally narrower than its seal strength window, so dwell time and cooling bar settings determine the maximum packaging speed on vertical form-fill-seal equipment. Compliance is determined on the finished laminate under FDA 21 CFR 177.1395 for retort pouches only when the structure and adhesive meet retort conditions; for hot-fill, FDA 21 CFR 177.1520(c) and EU Regulation (EU) No 10/2011 are applied to the sealant layer. A major boundary is that 8656RK must not be used as the sole sealant in true retort pouches above 121 °C, especially with high-acid tomato products requiring 60-minute cook cycles, because the mLLDPE layer can soften, thin, and delaminate from the barrier. Conversely, hot-fill at 90 °C for 30 min is within the material’s operational boundary provided the laminate is cooled under positive pressure to prevent air entrapment at the seal edge.
Thermal Stability Governs Collation Shrink Film Output With 8656RK
Collation shrink film made from 8656RK is typically blended with LDPE and a C6 or C8 LLDPE to balance free shrink, puncture resistance, and melt strength. A representative formulation is 50–60 wt% 8656RK, 25–35 wt% LDPE with melt index 0.2–0.4 g/10 min, and 10–15 wt% C6-LLDPE; the film is run at 60–90 µm on a high-stalk blown line with BUR 2.5–3.5, die gap 1.8–2.0 mm, and melt temperature 210–225 °C. High-molecular-weight resin maintains bubble stability during orientation at low frost line heights, but rapid quenching below 10 °C air temperature can increase blocking and reduce shrink force. The end products are distribution collation wrap, bottle multipack overwrap, and printed shrink film. Free shrink in oil at 150 °C is measured by ASTM D2732, and shrink force is recorded using a shrinkage force tester; 8656RK-rich films generally exhibit lower maximum shrink force than LDPE-rich films but higher puncture energy retention at -20 °C. Die pressure increases as 8656RK exceeds 60 wt%, so extrusion at high output above 150 kg/h on a 250 mm die may require a die gap increase to 2.2 mm to avoid melt fracture at the outer die lip. Additives for slip and antiblock should not exceed 5000 ppm total in the shrink film if clarity is specified; for food-containing multipacks, the additive pack must be salt-free and the film must be evaluated under FDA 21 CFR 177.1520(c) and EU Regulation (EU) No 10/2011.
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- ExxonMobil Exceed XP mLLDPE XP 8656RK 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.
ExxonMobil Exceed XP mLLDPE XP 8656RK is an ethylene-hexene copolymer produced with a metallocene catalyst system and supplied in pellet form for blown film extrusion. The nominal melt index is 0.5 g/10 min measured under ASTM D1238 at 190 °C with a 2.16 kg piston load; the nominal density is 0.916 g/cm³ measured under ASTM D1505. The grade is designed for film thicknesses from 25 µm to 150 µm where impact strength, tear resistance, and bubble stability are more critical than ultra-high clarity. The RK suffix identifies a defined antioxidant and processing-stabiliser package rather than a change in base-resin architecture; exact additive composition is lot-specific and should be confirmed against the certificate of analysis because slip, antiblock, and heat-seal behaviour are additive-dependent. Published data for this specific configuration is limited when non-neutral additive packages are substituted.
Compared with C4-butene Ziegler-Natta LLDPE of equivalent density and melt index, the hexene comonomer and metallocene architecture produce a narrower molecular weight distribution and a more uniform short-chain branching distribution across the molecular weight range. This changes the failure envelope in blown film: low-molecular-weight chains with high comonomer content are reduced, decreasing extractable oligomers and improving organoleptic characteristics while simultaneously raising dart impact and puncture resistance. The property shift is measurable only when film is produced and tested under controlled conditions; dart impact is evaluated under ASTM D1709A, Elmendorf tear under ASTM D1922, tensile properties under ASTM D638 or ISO 527-3:2018, and secant modulus under ASTM D882. Film properties are not resin constants; they vary with die gap, blow-up ratio, frost line height, output, and cooling rate.
Why is low melt index the primary differentiator from general-purpose mLLDPE?
General-purpose hexene mLLDPE grades for thin-gauge film are often supplied at melt index values of 1.0 g/10 min or higher. XP 8656RK is specified at 0.5 g/10 min, which increases melt viscosity and bubble stability on high-stalk lines but lowers the maximum output on torque-limited extruders. Compared with a 1.0 g/10 min grade of equal density, the low-MI resin supports thicker frost line heights and higher blow-up ratios without bubble collapse, making it suitable for films above 50 µm. The trade-off appears as higher head pressure and higher melt temperature at constant screw speed; on a 60 mm grooved-feed extruder with 24:1 L/D, pressure and torque increases relative to a 1.0-MI grade should be recorded during comparative trials because screw design, barrel temperature profile, and die restriction determine the exact magnitude. Published data for this specific configuration is limited in public literature.
For blown film extrusion of XP 8656RK, a die gap of 1.5–2.0 mm is typically maintained for high-stalk bubble geometry, with a blow-up ratio of 2.0:1 to 2.5:1 and a frost line height of 1.0–2.0 die diameters above the air ring. Barrel temperatures are set in the range 160–180 °C, adaptor and die temperatures at 190–210 °C, and melt temperature at the die is commonly held between 199 °C and 221 °C. The lower melt index raises shear heating; therefore, screw speed rather than barrel temperature is the primary control when melt temperature approaches 230 °C. Die gaps below 1.0 mm or output rates that push die-lip shear rates beyond the onset of sharkskin can produce surface melt fracture; a fluoropolymer processing aid at 200–800 mg/kg is commonly added to reduce die lip build-up and postpone melt fracture. Internal bubble cooling widens the process window but alters bubble stability and gauge distribution; when internal bubble cooling is used, the blow-up ratio may be increased to 2.5:1 or higher provided that film tear balance remains acceptable under ASTM D1922.
On single-screw lines with 24:1 to 30:1 L/D, a conventional three-zone screw with a Maddock mixing section is adequate for homogenisation, but a barrier screw gives better melt-temperature control with this low-MI grade. Grooved-feed extruders are preferred for consistent feeding because the lower melt index reduces screw fill sensitivity. Output, not temperature, is the main lever for film impact and haze; higher output typically reduces haze because of greater molecular orientation but may increase variability in transverse-direction gauge on oscillating haul-off equipment. Lot-to-lot variation in the RK additive package can influence surface roughness and coefficient of friction; film producers should track ASTM D1894 coefficient of friction and ASTM D3354 blocking force when changing lot numbers.
Surface moisture condensation on cold pellets can cause feed throat bridging and surface defects. Drying is not required for bulk moisture absorption because polyethylene is not hygroscopic, but a desiccant hopper set at 60–80 °C for 2 h is used when pellets have been stored in unheated warehouses with relative humidity above 60%. Extended storage should remain below 50 °C and out of direct sunlight to avoid additive depletion and yellowing.
Melt index, density, and lot-specific additive-suffix implications
| Parameter | Method | Value |
|---|---|---|
| Melt index | ASTM D1238, 190 °C/2.16 kg | 0.5 g/10 min |
| Density | ASTM D1505 | 0.916 g/cm³ |
| Comonomer type | ExxonMobil internal method | Hexene-derived short-chain branching |
| Additive package | Certificate of analysis | Lot-specific stabiliser; RK suffix |
The combination of 0.5 g/10 min melt index and 0.916 g/cm³ density positions XP 8656RK between softer, high-puncture mLLDPE grades and stiffer, higher-density mLLDPE grades. A lower-density mLLDPE at 0.912 g/cm³ would provide greater flexibility and puncture resistance but lower modulus; a higher-density grade at 0.918–0.920 g/cm³ would provide higher secant modulus but may sacrifice dart impact and tear propagation resistance. The density difference is not the only variable; hexene comonomer length and catalyst architecture influence tie-molecule concentration and crystalline morphology, which affect Elmendorf tear and slow crack-growth resistance in thick films. Property comparisons should be made on film of identical gauge and processing history, using ASTM D1709A for dart impact, ASTM D1922 for tear, and ASTM D5748 for puncture resistance.
Processors should not interpret the nominal density value as a direct predictor of stiffness in thin films. Secondary crystalline morphology is strongly affected by air-ring cooling rate, die gap, and haul-off speed; therefore, secant modulus measured according to ASTM D882 may differ from values predicted from density alone. Published data for this specific configuration is limited when orientation is varied; pilot-line trials are required to establish the relationship between blow-up ratio, frost line, and secant modulus.
The RK suffix should not be interpreted as a universal slip or antiblock designation. Film coefficient of friction and blocking force depend on whether the lot contains amide-based slip agents, synthetic silica antiblock, or neither. If low coefficient of friction is required, processors may add masterbatch-based slip and antiblock, but additions above 1,000 mg/kg of amide-based slip agents can bloom to the surface and reduce heat seal strength measured under ASTM F88. Seal initiation temperature must be verified on the final film because the base resin and additive package influence hot-tack and seal windows; hot-tack testing is performed according to ASTM F1921.
Heavy-duty sacks produced from XP 8656RK are typically extruded at film thicknesses from 75 µm to 150 µm and tested for puncture resistance under ASTM D5748, Elmendorf tear under ASTM D1922, and tensile strength at break under ASTM D638. The resin is often blended with 5–20 wt% LDPE to improve bubble stability and tear balance; blend ratios beyond 20 wt% LDPE may reduce dart impact and puncture resistance and should be qualified on production-scale equipment. Agricultural films such as silage wrap and greenhouse covers require UV stabilisation; the base resin is not inherently UV-stable, and hindered amine light stabiliser masterbatches are added at 0.5–2.0 wt%. Outdoor performance is validated according to ISO 4892-2 or ASTM G154 on the final film formulation, not on unmodified pellets.
Food-contact applications require confirmation that the final plastic article meets FDA 21 CFR 177.1520 for olefin polymers and EU Regulation 10/2011 for plastic materials and articles intended to come into contact with food. Overall migration testing according to EN 1186-1 and specific migration testing for additives in the RK package must be conducted under the actual time and temperature conditions of use. The as-supplied resin does not automatically guarantee compliance for all food types; fatty foods, high-temperature filling, and alcohol-containing products require separate validation because migration kinetics in polymer matrices are dependent on the additive package and film thickness.
When low-melt-index mLLDPE restricts output on 45 mm single-screw blown-film lines
On 45 mm single-screw extruders with 24:1 L/D, XP 8656RK may be difficult to process at high throughput because the low melt index increases melt viscosity and shear heating. Operators typically reduce screw speed, lower rear barrel temperatures to 140–160 °C, and increase die temperature to maintain a melt temperature below 220 °C. If the extruder is torque-limited, blending with 10–20 wt% of a 0.25–0.7 g/10 min LDPE can reduce head pressure and improve bubble stability, but the blend will change dart impact, tear, and stiffness; the final blend must be revalidated under ASTM D1709A, ASTM D1922, and ASTM D5748. Bubble instability in high-stalk operation may occur when the frost line moves above 2.0 die diameters; lowering the air ring, reducing internal bubble cooling airflow, or increasing melt temperature within the recommended range can restore a stable bubble. Extended residence time above 230 °C can initiate oxidative degradation and gel formation, which appears as fisheyes in film and is detected by optical surface inspection systems.
Cast film extrusion is not the primary design target for this grade. The low melt index can produce draw resonance and neck-in on cast lines unless melt temperature is raised above 240 °C, which is not recommended for extended run times because of additive degradation and gel risk. Published data for this specific configuration is limited when the resin is run on high-speed cast film lines with short feedback adaptors.
Storage and handling boundaries are similar to other LLDPE grades. Pellets should be kept in sealed packaging below 50 °C, protected from direct sunlight, and purged with dry air if ambient relative humidity exceeds 60%. Surface condensation on cold pellets can cause feed throat bridging and film surface defects, but polyethylene does not require bulk moisture drying under normal conditions. The grade is not recommended for applications requiring continuous contact with strong oxidising agents, copper-based biocide systems, or certain halogenated flame retardants because these compounds can accelerate thermo-oxidative degradation at processing temperatures or in service. Published data for this specific configuration is limited for such contact environments; alternatives should be qualified against the final article’s performance and regulatory requirements.
