Material data ALK / POLY

Grades we convert, and what they hold

Four base polymers, each held in more than one grade. The right grade depends on wall section, service temperature, contact medium and the shape you need it to hold.

All values below are indicative placeholders. Issued grade sheets carry the resin supplier's certified data for the specific batch.

Grade catalogue

Base polymers in production

Hover or focus a card for the full property set. Grades are listed by our internal designation; the supplier equivalent is stated on the issued grade sheet.

ALK-HD-BM-6070

HDPE — high-density polyethylene

The workhorse for containers and pressure pipe. Stiff, chemically resistant, and tolerant of rough handling in transit and on site.

Density 0.952–0.960 g/cm³
Melt flow index 0.3 g/10 min @ 190 °C
Tensile strength 26 MPa at yield
Processing temp. 180–220 °C
Service temp. −40 to +60 °C
Converted by Blow moulding, extrusion

Jerry cans Pressure pipe Crates

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ALK-LD-FL-2420

LDPE — low-density polyethylene

Soft, clear and forgiving on the seal. Used where the film has to stretch and stay intact rather than hold a shape.

Density 0.921–0.925 g/cm³
Melt flow index 2.0 g/10 min @ 190 °C
Tensile strength 12 MPa at yield
Processing temp. 160–200 °C
Service temp. −50 to +50 °C
Converted by Film extrusion

Blown film Liners Shrink hoods

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ALK-PP-IM-1100

PP — polypropylene

Higher service temperature than PE and a living hinge that survives repeated flexing. The default for closures and stacking crates.

Density 0.900–0.910 g/cm³
Melt flow index 11 g/10 min @ 230 °C
Tensile strength 33 MPa at yield
Processing temp. 200–250 °C
Service temp. −10 to +100 °C
Converted by Injection moulding

Closures Stacking crates Hot-fill parts

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ALK-PVC-PE-0670

PVC — polyvinyl chloride

Rigid, flame retardant and dimensionally stable. Specified for conduit, drainage and building applications where PE would creep.

Density 1.38–1.42 g/cm³
Melt flow index K-value 67
Tensile strength 48 MPa at yield
Processing temp. 170–190 °C
Service temp. −5 to +60 °C
Converted by Extrusion

Conduit Drainage pipe Profiles

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Tolerances

Extrusion and moulding tolerance bands

Tolerance register — all figures are placeholders pending client confirmation
Controlled property	Product class	Nominal	Tolerance band	Verification method
Wall thickness	Pressure pipe	Per nominal class	+0.40 / −0 mm	Ultrasonic in-line gauge
Outside diameter	Pressure pipe	16–400 mm	±0.3 %	Laser micrometer, continuous
Part weight	Injection mouldings	Per drawing	±2 %	Sample weighing, hourly
Container weight	Blow mouldings	Per drawing	±3 %	Sample weighing, hourly
Film gauge	Blown film	20–200 µm	±5 %	Cross-web thickness gauge
Cut length	Rigid pipe, cut lengths	6.00 m	+20 / −0 mm	Measured per bundle

Where a customer specification or a national standard states a tighter band than the one above, the tighter band applies and is written into the order confirmation.

Additives

Masterbatch and modification

Base resin is rarely the whole specification. State the service environment and we will state the additive package.

ADD / UV

UV stabilisation

For product held or used in open sun. Specify expected outdoor exposure in months and we will set the loading accordingly.

ADD / COL

Colour masterbatch

Matched to a supplied reference or a stated colour standard. Colour is dosed at the line, not pre-compounded, so a repeat order matches the retained sample.

ADD / AST

Antistatic and slip

For film that has to run cleanly on an automatic packing machine rather than cling to itself on the reel.

ADD / FCG

Food-contact grades

Available on nominated products with supporting documentation from the resin supplier. Confirm the intended contact medium at enquiry stage.

Recycled content

Regrind and recycled input

Internal regrind from our own process is reintroduced on nominated products at a controlled ratio, recorded against the lot. Products with a recycled content requirement — or a strict prohibition on it — must state that at order stage, because it changes both the grade sheet and the price.

Need a grade sheet for a specific application?

Tell us the contact medium, service temperature, wall section and expected life. We will nominate the grade and issue the data sheet.

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