ISO 13636 Non-oriented PET Films sheeting test requirement (APET)

Information on the most widely used ASTM standards within the materials testing industry

Descriptions of the most prominent lSO standards within the materials testing industry

Standards including EN, DIN, JlS, and more

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ISO 13636 Plastics – Film and sheeting – Non-oriented poly(ethylene terephthalate) (PET) sheets

ISO 13636 outlines complete specifications and standardized test methods for non-oriented PET (APET) plastic sheets with a thickness below 2.0 mm. These APET sheets can be manufactured using virgin PET resin, recycled PET material, or a blend of both raw material types.

This international standard clearly excludes foamed PET sheets and heat-shrinkable PET films, as those products fall under separate testing regulations — biaxially oriented BOPET film quality control, for instance, is governed by ISO 15988 instead.

ISO 13636 enforces a series of mandatory performance testing benchmarks for APET sheet quality verification. Required core test metrics cover tensile stress at yield, thermal heat shrinkage, oxygen transmission rate (OTR), haze value, and intrinsic viscosity (IV).

Core regulatory functions:

Raw material classification (virgin / food-grade recycled / non-food recycled PET)

Sheet structural classification (single / two / three-layer coextruded)

Intrinsic viscosity (IV) grading matching thermoforming applications

Mandatory visual, mechanical, thermal, optical, barrier and hygiene test requirements

Uniform sampling, conditioning, test procedures, dimension tolerances, packaging and marking rules

Target Industry Application Fields of ISO 13636

ISO 13636 governs APET sheet used globally in these core sectors:

Food thermoforming packaging (largest application)

Disposable food trays, salad containers, bakery clamshells, cold deli packaging, blister packs for ready meals. Multi-layer APET structures with food-safe virgin outer layers and recycled PET core layers are widely adopted here.

General consumer blister packaging

Clear blisters for electronics, stationery, toys, cosmetic cases (non-food grades using non-food recycled PET).

Deep-drawn thick-wall packaging

High-IV grade APET for deep thermoformed containers requiring rigidity and impact resistance.

ISO 13636 Non-oriented PET Films sheeting test requirement (APET)

Heat-resistant CPET containers

Highest IV class (≥0.80 dl/g) for microwaveable dual-ovenable food packaging.

Transparent rigid display films

Retail shelf display sheets, window inserts requiring low haze and uniform tensile strength.

Properties tested under ISO 13636

#	Property	Unit	Requirement	Standard
1	Tensile stress at yield (MD / TD)	MPa	≥ 45	ISO 527-1, ISO 527-3
2	Heat shrinkage (MD)	%	≤ 3	ISO 11501
3	Oxygen transmission rate (OTR)	10⁻¹⁶ mol·m/(m²·s·Pa)	≤ 1	ISO 15105-1 / 15105-2
4	Haze (transparent sheet)	%	≤ 10	ISO 14782
5	Intrinsic viscosity (IV)	dl/g	per standard	ISO 1628-5

Full Breakdown of Tests Stipulated in ISO 13636 for APET films sheets

1, Tensile Stress at Yield	Quantify sheet rigidity and forming resistance; yield strength determines minimum force required to deform APET during thermoforming, critical for mold design and processing parameter setup. ISO 13636 mandates a minimum yield stress of 245 MPa for both MD and TD to guarantee consistent forming performance.
Practical Mechanical Significance	APET is slightly anisotropic from extrusion flow; balanced MD/TD yield strength ensures uniform stretching during thermoforming, eliminating thin spots, or uneven wall thickness in finished containers. Recycled PET with degraded molecular weight often fails this test, so tensile yield stress acts as a quick quality screen for contaminated recycled feedstock.
Specimen Information	Specimen geometry: ISO 527-3 Type 2 rectangular strip (standard film sheet specimen) Quantity: Minimum 5 replicates for machine direction (MD), minimum 5 replicates for transverse direction (TD) Cutting rule: Specimens cut from sheet central transverse zone, uniform length/width; all edges smooth, no nicks or micro-cracks (discard defective samples per ISO 2818 machining rules) Conditioning: 48 h standard atmosphere hold prior to testing
Test Equipment	Universal tensile testing machine (load cell precision ≤ ±1% full scale) Pneumatic non-slip rubber-coated grips (to prevent sheet slippage without edge crushing) Specimen cutting die for ISO 527-3 Type 2 rectangular strip specimens Thickness gauge for cross-sectional area calculation.
Test Procedure	Measure width and thickness of each specimen at three positions, calculate average cross-sectional area Mount specimen vertically in tensile grips with zero pre-tension Set constant test speed: 50 ±5 mm/min (fixed by ISO 13636 reference to ISO 527-1) Run tensile extension until yield point is clearly observed on force-displacement curve Record yield force for each replicate; compute average tensile stress at yield for MD and TD separately Report average MD and TD yield stress values (unit: MPa)
Mandatory Stipulations	Minimum tensile stress at yield: 245 MPa in both machine and transverse directions.
2, Heat Shrinkage Test (Thermal Stability Test)	Evaluate dimensional stability under thermal processing (thermoforming oven heating, post-forming hot filling); excessive shrinkage causes tray warping, dimensional deviation of finished packaging.
Industrial Mechanical Relevance	APET thermoforming processes use 80–120 °C heating zones; the 60 °C / 30 min accelerated test simulates low-temperature thermal exposure to predict in-process shrinkage. High IV grades (IV3, IV4) exhibit lower shrinkage due to longer molecular chains, which is why deep-draw and heat-resistant containers specify higher IV classes.
Specimen Information	3 replicate specimens cut from sheet central transverse area; square/rectangular blanks sized to mark clear MD gauge lines; only machine direction shrinkage is tested per ISO 13636 stipulation
Test Equipment	Film Thermal Shrinkage Tester, Size Change Measuring Tester; Circulating air laboratory oven (temperature control ±1 °C, minimum 6 air exchanges per hour) Flat kaolin-filled metal tray (20 mm kaolin bed depth to support specimens flat without tension) Precision linear scale (0.5 mm resolution), stopwatch
Test Procedure	Mark two clear gauge marks along machine direction on each specimen, measure initial gauge length accurately Place specimens flat on kaolin bed inside preheated oven at 60 °C (fixed test temperature specified by ISO 13636) Hold constant heating time: exactly 30 minutes Remove specimens, cool fully to standard test atmosphere temperature Re-measure gauge length along MD, calculate shrinkage percentage for each replicate Report average heat shrinkage rate of three samples
Mandatory Stipulations	Heat shrinkage percentage (MD) ≤ 3 %.
3, Oxygen Transmission Rate (OTR) Test (Barrier Functional Test)	Measure oxygen permeability of transparent APET packaging; critical for shelf life of oxygen-sensitive food (meat, fruit, baked goods). ISO 15105-1 (differential pressure gas transmission method), ISO 15105-2 (equal pressure coulometric method)
Specimen Information	Minimum 3 specimens cut from sheet central transverse region; specimen size matches instrument test cell aperture
Test Equipment	Oxygen permeability tester , OTR test instrument (either differential pressure or equal pressure coulometric analyzer) Temperature/humidity controlled test cell matching ISO 291 atmosphere
Test Procedure	Condition specimens 48 h per ISO 291 Mount specimen to fully seal test cell, separate high-oxygen and low-oxygen chambers Run test until stable transmission rate reading is achieved Record OTR for each replicate, average three results to three significant figures Test report must include instrument model, test method (ISO 15105-1 / 15105-2), and reference to ISO 13636
Mandatory Stipulations	OTR ≤ 1 ×10⁻¹⁶ mol·m/(m²·s·Pa)
4, Haze Test (Optical Clarity Test for Transparent Packaging)	Quantify light scattering (cloudiness) of APET sheet; consumer food packaging requires high transparency for product visibility, with haze capped at ≤10 %.
Specimen Information	Minimum 3 specimens from sheet central transverse area, free of surface scratches or contamination
Test Equipment	Hazemeter (calibrated per ISO 14782).
Test Procedure	Condition specimens for 48 h standard atmosphere Measure haze value on each replicate specimen at multiple positions Report average haze percentage of three samples
Mandatory Stipulations	Haze ≤ 10 % (only applies to transparent APET grades)

Related Standard

JIS Z 1716	Non-oriented polyethylene terephthalate (PET) sheets and films for packaging
ISO 15270	Plastic waste recycling guidelines (recycled PET process control)
ISO 17555	Plastics - Film and sheeting - Biaxially oriented polypropylene (PP) films
ISO 15987	Plastics - Film and sheeting - Biaxially oriented polyamide (nylon) films
ISO 15988	Plastics - Film and sheeting - Biaxially oriented poly(ethylene terephthalate) (PET) films
TCVN 10104	Plastics. Film and sheeting. Non-oriented poly(ethylene terephthalate) (PET) sheets
GB/T 41791	Plastics—Film and sheeting—Non-oriented poly(ethylene terephthalate) (PET) sheets
Related Test Standard	ISO 527-1: Tensile test general principles (yield stress mechanical test core standard) ISO 527-3: Tensile test conditions for films & sheets (specimen geometry for APET tensile testing) ISO 1628-5: Dilute solution viscosity for thermoplastic polyesters (IV measurement) ISO 2818: Machining plastic test specimens (defect-free tensile sample preparation) ISO 11501: Dimensional change on heating (heat shrinkage test method) ISO 14782: Haze measurement for transparent plastics ISO 15105-1 / 15105-2: Gas transmission rate (oxygen barrier test)

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Thin Plastic Film Tensile Testing Fixture is specially designed for tensile strength testing of flexible and soft plastic film specimens. Fully compliant with the ASTM D882 standard for thin film tensile testing, the fixture features premium rubber-coated jaws.

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Adopts advanced electrochemical coulometric detection method for accurate, time-efficient oxygen transmission rate analysis for medium and high barrier packaging materials. Conform with ISO 15105-2, ASTM D3985. Key testing indicators Oxygen Transmission Rate (OTR), oxygen volume passing through.

Professional film heat shrink tester is precision lab equipment engineered to evaluate thermal shrinkage characteristics and thermal dimensional stability of diverse raw materials, including plastic films. compliant with international testing standards ASTM D2732 and ISO 11501.

Pipe Size Change Measuring Tester/ Longitudinal Reversion Tester suitable to measure various kinds of plastic pipe or plastic materials size change after heating, or used to heat the test sample. It can be used as a heating oven as well.

Q1: What is ISO 13636:2012, and why is it separate from ISO 15988 (oriented PET film)?

A: ISO 13636:2012 is the global standard for non-oriented amorphous PET (APET) sheets (<2 mm thick), covering raw material classification, performance requirements, uniform test protocols, marking and packaging rules.

ISO 15988 only governs biaxially oriented crystalline BOPET. APET has unordered, non-crystalline molecular chains, leading to vastly different tensile, thermal shrinkage and barrier properties. Oriented and non-oriented PET cannot share identical test limits or grading rules, so ISO developed a dedicated standard for APET thermoforming sheets.

Q2: Why is ISO 13636 critical for APET sheet manufacturers, converters and food packagers?

A: 4 core reasons:

Unified global benchmark: Eliminates inconsistent lab test results between suppliers and buyers across cross-border supply chains.

Recycled PET circular economy framework: First international standard allowing controlled food-grade recycled PET (rPET) in multi-layer APET, with clear raw material codes (V, MRP-FD, MRG-FI, MRG-NF) to avoid regulatory violations.

Thermoforming performance grading: Intrinsic viscosity (IV) classification directly matches deep-draw, heat-resistance and mechanical strength needs for different packaging applications.

Food safety alignment: Links sheet layer construction to regional food contact laws (EU 282/2008, US FDA) and defines clear direct/indirect food contact usage limits.

Mechanical failure prevention: Mandatory tensile yield and heat shrinkage tests predict thermoforming defects (tearing, warping) before mass production.

Q3: What materials and products does ISO 13636 exclude from its scope?

A: The standard only applies to solid, non-foamed APET sheets thinner than 2.0 mm. It explicitly excludes:

Foamed PET sheets

Heat-shrink oriented PET films

Sheets thicker than 2.0 mm

Injection-molded PET rigid containers (covered by ISO 7792-1 instead)

Q4: What are the key upgrades of ISO 13636 compared to its base standard JIS Z 1716:2004?

A: The original Japanese JIS standard only permitted virgin PET resin. ISO 13636 added three major expansions:

Allows classified recycled PET under controlled treatment processes for food/non-food applications

Standardizes single/two/three-layer coextruded sheet classification and naming rules

Integrates cross-regional food hygiene regulatory alignment for international packaging trade.

Q5: Where must test specimens be cut from the APET sheet, and why avoid edge samples?

A: All specimens for tensile, shrinkage, IV, haze and OTR tests must be taken from the central transverse zone of the sheet roll/panel.

Sheet edges have uneven extrusion flow, inconsistent thickness, residual edge stress and surface defects, which will create biased low/high mechanical performance readings that do not represent the bulk production quality.

Q6: Why does the tensile test fix crosshead speed at 50 ±5 mm/min? Can I use other speeds?

A: 50 mm/min is standardized in ISO 527-3 for thin plastic sheets to simulate the strain rate APET experiences during thermoforming mold stretching. Faster speeds artificially raise yield strength; slower speeds lower results. Deviating from the fixed speed makes test data incomparable between suppliers and fails ISO 13636 compliance requirements.

Q7: Why does ISO 13636 only test heat shrinkage in machine direction, not transverse direction?

A: Extrusion stress primarily accumulates along the machine (length) direction of the sheet; transverse shrinkage is negligible and does not impact thermoforming dimensional stability. Restricting testing to MD optimizes lab workflow while capturing the critical shrinkage failure mode.

Q8: If an APET sheet passes tensile yield test but fails heat shrinkage limit, what does this indicate?

A: Two typical root causes:

Extrusion line cooling was too fast, trapping excessive residual stress in the sheet

Low intrinsic viscosity (IV1/IV2) PET resin with short polymer chains that relax easily under heat

The sheet cannot be used for precise dimensional thermoformed packaging (e.g., tight-lid food containers). Switching to higher IV resin or adjusting extruder cooling will reduce shrinkage.

Q9: What is intrinsic viscosity (IV) test, and how does it link to APET mechanical performance?

A: IV (dl/g) measures PET molecular chain length via dilute solution viscosity (ISO 1628-5). ISO 13636 divides sheets into 4 IV classes directly tied to mechanical/thermal properties:

IV Class	IV range (dl/g)	Typical use
1	< 0.60	Low-strength packaging
2	0.60–0.70	General thermoforming
3	0.70–0.80	Thick-wall / deep-draw
4	≥ 0.80	Heat-resistant CPET (ovenable)

Higher IV = longer polymer chains = higher tensile yield strength, lower heat shrinkage, better deep-draw capability.

Q10: Can I convert MVR (melt volume rate) values to IV instead of running solvent viscosity testing?

A: Yes, ISO 13636 permits IV conversion from MVR data measured via ISO 12418-2 for recycled PET batches, but solvent-based IV testing (8.3) remains the official referee test for compliance certification.

Q11: Why is haze testing capped at ≤10% for transparent APET sheets?

A: Haze measures light scattering from crystallites, surface scratches or resin contamination. Food packaging requires clear visibility of products; haze above 10% creates cloudy, low-aesthetic trays unsuitable for retail food display. The test follows ISO 14782 with minimum 3 replicate specimens.

Q12: What oxygen transmission rate (OTR) limit is required, and why is it paired with mechanical tests for food packaging?

A: OTR ≤1 ×10⁻¹⁶ mol·m/(m²·s·Pa) (ISO 15105-1 / 15105-2).

Low oxygen permeability extends shelf life of oxygen-sensitive foods (meat, baked goods). Even if a sheet meets all mechanical requirements, high OTR renders it useless for fresh food packaging applications.

Q13: If APET fails tensile yield stress test, what are the common root causes?

A: Recycled PET feedstock with low IV (severe molecular degradation from repeated recycling)

Extruder overheating breaking PET polymer chains

Insufficient sheet drying before extrusion (moisture-induced chain hydrolysis)

Contamination with incompatible plastic scrap mixed into resin

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