Idemitsu HDPE CALP H100 is a high-density polyethylene resin supplied by Idemitsu Kosan Co., Ltd. and positioned within the company’s HDPE portfolio for calendered sheet, technical sheet, and thick-gauge polyolefin conversion where a low melt flow rate and high melt strength are required. The designation “CALP H100” is a grade identifier; it does not by itself specify density, comonomer type, or molecular weight distribution. Classification under ISO 1183-1 places the material in the high-density polyethylene range because the base resin density is not lower than 0.940 g/cm³. Exact release values, additive composition, and lot-specific molecular architecture are recorded on the supplier’s certificate of analysis rather than in this informational overview.

Published data for this specific configuration is limited in some end-use areas. The content below therefore separates standardised characterisation methods, product-class behaviour, and information that must be obtained from the current Idemitsu technical data sheet before production validation.

Physical property framework and specification references

Table 1 lists the standard test methods commonly used to characterise high-molecular-weight HDPE calendering grades and the expected engineering envelope for a product of this class. The numerical ranges are not contractual release limits for Idemitsu HDPE CALP H100; they are included to support feasibility assessment and should be replaced with the supplier’s current lot-specific values before tooling or process parameters are fixed.

Test specimens for the mechanical values in Table 1 are typically prepared and conditioned according to ISO 1872-2 and ISO 291. A single melt-flow point at 2.16 kg does not fully capture shear sensitivity or the high-molecular-weight tail. If extruder or melt-pump sizing is required, the flow rate ratio using the 21.6 kg load should be requested from Idemitsu as a complement to the standard 2.16 kg melt flow rate.

Calendering-grade HDPE of this type is usually fed to a four-roll inverted-L calender from a planetary roller extruder or a two-stage kneader. The melt bank in the nip must remain homogeneous; if the stock temperature is too low, high-molecular-weight particles fail to fuse and produce pitting or microgrit on the sheet surface. If the stock temperature is too high, shear-induced heat at the roll surface can initiate local thermal oxidation and yellowing. The practical working window is therefore narrower than the data-sheet melting range alone suggests.

How does the melt rheology of CALP H100 constrain calender throughput?

The melt flow rate of CALP H100 is the principal control variable. At 190°C and 2.16 kg, a product of this class typically tests below 0.10 g/10 min, which corresponds to a high average molecular weight and a long stress relaxation time. In a single-screw extruder, this translates into high head pressure and torque-limited operation. Stable output normally requires a grooved-feed section, a barrier-flight screw, and an L/D ratio of at least 28:1. Production lines with L/D below 24:1 may experience surging and excessive pressure fluctuation when processing this material.

Rotational rheometry under ISO 6721-10 can provide complex viscosity data for quality comparison, but capillary rheometry under ISO 11443 is more directly relevant for die and calender-nip design. Without capillary data for the specific grade, flow simulation should not be attempted, because the molecular weight distribution of HDPE strongly affects shear thinning and entrance pressure loss. A narrower molecular weight distribution may reduce melt fracture at high throughput but can also reduce melt strength; the actual distribution for CALP H100 should be confirmed with the supplier.

High melt strength is beneficial for roll-bank stability and gauge uniformity, but it also increases the power demand in the roll nip. On a four-roll calender, the separating force can be higher than that observed with flexible PVC or low-density polyethylene at equivalent sheet thickness. Roll bending and crown compensation must be adjusted to maintain a flat gauge profile; otherwise edge thickening or centre buckling occurs. Draw resonance on the take-off section generally appears as sinusoidal gauge bands when haul-off speed is too high relative to melt extrusion rate. Reducing draw ratio or increasing the die gap is normally required before reducing line speed is considered.

Adding 0.5–1.5 wt% of an external lubricant or processing aid may reduce melt fracture and roll-sticking tendency, but it can also lower surface energy and impair printing or corona-treatment adhesion. Such modifications should be qualified against the full final specification before production is authorised.

If CALP H100 replaces a conventional blown-film or injection HDPE grade

Substitution review should begin with melt flow rate and density. Injection-moulding HDPE grades commonly test in the 4–20 g/10 min range under ISO 1133-1, whereas blown-film HDPE grades often test at 0.2–1.2 g/10 min. Idemitsu HDPE CALP H100 belongs to a lower-MFR class; it is not appropriate for thin-wall injection moulding because high melt viscosity can produce short shots, high packing pressure, and excessive clamp force. In thick-wall or compression-like filling paths, some sheet and block applications may be physically possible, but mould shrinkage and cooling time must be recalculated from new process data.

Compared with blown-film HDPE, CALP H100 may provide higher melt strength and more stable sheet or film formation, but the converter should expect higher extruder backpressure, lower screw output at equivalent rpm, and higher energy input per kilogram. Those differences are measurable on production equipment as an increase in motor load and melt temperature. A die temperature increase of 10–20°C may be necessary to reduce surface melt fracture when moving from a medium-MFR film grade to CALP H100.

Compared with low-density polyethylene or linear low-density polyethylene, HDPE CALP H100 offers higher stiffness and modulus, but lower optical clarity and reduced low-temperature impact resistance. HDPE is also more crystalline, with a melting plateau above 125°C rather than the 100–115°C range typical for LDPE. This difference must be considered when the material is introduced into a sheet line previously used for LDPE, because heater settings, chill-roll temperatures, and trim baler behaviour will not transfer directly.

Regulatory documentation is incomplete without the resin supplier’s additive disclosure

For food-contact articles, olefin base polymers can be cleared under FDA 21 CFR 177.1520 and, in the European Union, under Commission Regulation (EU) No 10/2011. These clearances apply only when the final article meets overall migration and, where applicable, specific migration limits. Additives such as slip agents, antistatic agents, nucleators, or processing stabilisers must have their own authorisations. A converter cannot infer food-contact compliance from the base resin alone, and finished-article testing remains the responsibility of the company placing the packaging on the market.

REACH compliance for the polymer in the EU depends on the registration status of the monomer and any intentionally added substances. Although polymers are generally exempt from direct registration, their constituent monomers require registration under REACH Article 6. RoHS compliance is usually met by unmodified polyolefin resins unless conductive fillers, heavy-metal-based pigments, or brominated flame retardants are introduced downstream. Electrical or electronic applications should be supported by a documented RoHS assessment from the final compounder.

Storage and handling are relatively simple because HDPE is not hydrolytically sensitive. However, surface condensation can introduce water into the feed throat and create splay or surface irregularities in the sheet. If bags have been stored below 10°C and then transferred to a warm production hall, hopper drying at 80°C for 2 h is prudent. The dryer dew point should be below -20°C for best results. Extended storage beyond the supplier’s recommended shelf life should be validated by melt-flow testing and oxidative induction time under ISO 11357-6.

End-use failure modes are governed by orientation, thickness, and contact media

Impact strength of HDPE CALP H100 is dependent on test temperature and sheet thickness. Charpy values from Table 1 are not sufficient to predict puncture performance of a thermoformed part; instrumented puncture testing under ISO 6603-2 at the intended service temperature is required. Stress-cracking resistance under detergent or solvent exposure should be assessed with ASTM D1693 or full container testing if the material is placed in contact with surfactants, oils, alcohols, or aggressive cleaning agents. High-molecular-weight HDPE generally offers improved environmental stress-cracking resistance relative to low-molecular-weight grades, but the exact value for CALP H100 must be confirmed for the specific chemical environment.

Sheet orientation introduced during calendering and thermoforming changes mechanical properties directionally. A tensile specimen cut parallel to the calendering direction may show a higher yield stress than one cut transverse to the sheet. This anisotropy should be measured with ISO 527-3 or ISO 527-2 on production sheet before assigning material specifications to a formed part.

Outdoor use without UV stabilisation leads to oxidative embrittlement. If the application requires long-term exterior exposure, carbon black or a HALS-based UV package must be specified at the compounding step. Accelerated weatherability can be screened under ISO 4892-2, but correlation to real weathering must be established for the geographic exposure site and the specific end-use thickness.

Regrind of CALP H100 sheet can be dry-blended with virgin pellets up to 10–20 wt% in many calender operations, but the exact proportion must be determined by gel count, plate-out behaviour, and melt-flow stability. If the regrind contains print, label stock, or adhesive residue, it can generate surface defects and should be kept out of the primary melt stream. Reprocessing shifts the melt flow rate upward and reduces melt strength, so periodic verification of the regrind fraction is necessary to maintain the same sheet gauge profile.