Hytrel® 6646 NC010

Alternative and trade names
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Common features of Hytrel® thermoplastic polyester elastomer include mechanical and physical properties such as exceptional toughness and resilience, high resistance to creep, impact and flex fatigue, flexibility at low temperatures and good retention of properties at elevated temperatures. In addition, it resists many industrial chemicals, oils and solvents. Special grades include heat stabilised, flame retardant, food contact compliant, blow molding and extrusion grades. Concentrates offered include black pigments, UV protection additives, heat stabilisers, and flame retardants. Hytrel® thermoplastic polyester elastomer is plasticiser free.The good melt stability of Hytrel® thermoplastic polyester elastomer normally enables the recycling of properly handled production waste. If recycling is not possible, DuPont recommends, as the preferred option, incineration with energy recovery (-24 kJ/g of base polymer) in appropriately equipped installations.For disposal, local regulations have to be observed. Hytrel® thermoplastic polyester elastomer typically is used in demanding applications in the automotive, fluid power, electrical/electronic, consumer goods, appliance and power tool, sporting goods, furniture, industrial and off-road transportation/equipment industry.Hytrel® 6646 is a medium modulus grade with nominal hardness of 66D. It contains non-discoloring stabilizer. It can be processed by many conventional thermoplastic processing techniques like injection molding and extrusion.

This material data has been provided by Matmatch.

All metrics apply to room temperature unless otherwise stated. SI units used unless otherwise stated.
Equivalent standards are similar to one or more standards provided by the supplier. Some equivalent standards may be stricter whereas others may be outside the bounds of the original standard.

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23.0 °C

1.23 g/cm³

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ISO 1183

Water absorption

23.0 °C

0.6 %

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Sim. to ISO 62 | 80mil



Elastic modulus

23.0 °C

0.31 GPa

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ISO 527-1/-2


23.0 °C

380 %

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ISO 527-1/-2

Elongation at yield

23.0 °C

29 %

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ISO 527-1/-2

Hardness, Shore D

23.0 °C

66 [-]

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max., ISO 7619-1

Impact strength, Charpy notched

-6.0 °C

13 kJ/m²

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ISO 179/1eA

23.0 °C

110 kJ/m²

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ISO 179/1eA

Poisson's ratio

23.0 °C

0.48 [-]

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Tensile strength

23.0 °C

35 MPa

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ISO 527-1/-2

Yield strength

23.0 °C

20 MPa

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ISO 527-1/-2

Impact strength, Charpy unnotched

No Break @ 23°C, ISO 179/1eU



Glass transition temperature

0 °C

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ISO 11357-1/-2 | 18°F/min

Heat deflection temperature, 0.45 MPa

87 °C

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ISO 75-1/-2

Heat deflection temperature, 1.80 MPa

45 °C

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ISO 75-1/-2

Melting point

211 °C

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ISO 11357-1/-3 | 18°F/min

Specific heat capacity

23.0 °C

2150 J/(kg·K)

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of melt

Thermal diffusivity

23.0 °C

0 mm²/s

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Vicat softening temperature

100 °C

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ISO 306 | 90°F/h, 11 lbf


Burning Behav. at 60mil nom. thickn.: HB class, Thickness tested: 1.5 mm, Burning Behav. at thickness h: HB class, Thickness tested: 3 mm, Oxygen index: 21 %, FMVSS Class: B -, Burning rate, Thickness 1 mm: <80 mm/min

Rheological Properties


Melt mass-flow rate

13 g/10min

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ISO 1133 | 240°C/2.16kg


23.0 °C

1.4 %

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ISO 294-4, 2577

Shrinkage, transverse

23.0 °C

1.4 %

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ISO 294-4, 2577

Technological properties

Processing methods

Drying Recommended: yes, Drying Temperature: 110°C, Drying Time, Dehumidified Dryer: 2-3h, Processing Moisture Content: ≤0.08%, Melt Temperature Optimum: 245°C, Min. melt temperature: 240°C, Max. melt temperature: 260°C, Mold Temperature Optimum: 45°C, Min. mold temperature: 45°C, Max. mold temperature: 55°C, Hold pressure range: ≤70MPa