SPECFLEXTM NF 749 Polyol

SPECFLEXTM NE 447 Isocyanate

Description

SPECFLEX NF 749 Polyol and SPECFLEX NE 447 Isocyanate is 

a TDI/MDI based polyurethane flexible system with a final molded 

density of 40-50 kg/m3. The product is designed for short

demolding time and for both open and closed pour processing. It 

is suitable for a multiplicity of molded part sizes. The product 

is designed as the hard foam used in dual hardness backrest 

applications for the automotive market.

Typical Component Properties

Units SPECFLEX 

NF 749

Polyol

SPECFLEX 

NE 447 

Isocyanate

Test 

Method

Viscosity, 25°C Mpa.s 2700-4100 15 ASTM D 

445

Specific Gravity, 

25/25°C

- 1.04 1.22 ASTM D 

891

Recommended Process Conditions

Polyol needs to be properly mixed before use. Molds must be 

treated with a proper release agent.

Recommended Process Conditions

Units Limits

SPECFLEX NF 749 Polyol pbw 100

SPECFLEX NE 447 

Isocyanate

pbw 42-52

Component Temperature 

(Pol/Iso)

°C 20-25/20-25

Typical Molds Temperature °C 60-65

Demolding Time Min 4-6

Typical Reaction Characteristics1

Units

High 

Pressure 

Machine

Cream Time s 10-12

rise Time s 90

Free Rise Density 

(Core)

kg/m3

28.5

Handling and Storage

Units (1) SPECFLEX 

NF 749

Polyol

SPECFLEX 

NE 447 

Isocyanate

Storage Temperature °C 15-25 15-25

Storage Stablility / Shelf 

Life (1)

Months 6 6

1. Stored in the original sealed container in a dry place

at the recommended temperature protected from 

direct sunlight

Typical Polymer Properties

These items are provided as general information only.

Units Values Test 

Method 

Index 95 95 105 105 110 110

Core 

density kg/m3

35.7 41.5 35.8 40.6 34.1 41.7 JIS K 

6400 

Tensile 

strength kg/cm2 1.9 2.38 1.85 2.2 1.85 2.45 JIS K 6400 

Elongation % 90 88 80 80 78 78 JIS K 

6400 

Tear 

Strength kgf/cm 0.66 0.8 0.7 0.74 0.66 0.78 JIS K 6400 

Ball 

Resilience % 59 59 58 58 55 55 JIS K 6400 

Dry set % 5.8 5.8 5.7 5.2 6.0 5.2 JIS K 

6400 

Wet set % 22.2 20.2 22.2 17.9 21.7 19.0 JIS K 

6400 

25% ILD kgf/314cm2 20.49 28.93 25.61 31.04 25.41 38.67 JIS K 

6400 

Typical Polymer Fire Behavior

Numerical flame spread or fire classifications are not intended to reflect 

hazards presented by this or any other material under actual fire conditions.

Typical Polymer Fire Behavior

Standard Typical Values (1)

FMVSS 302 Pass

UNI CT 225 Pass

1. Numerical flame spread or fire classifications are only 

indicative; they are not sales specification. These results 

are obtained from tests in Dow laboratories on polymer lab 

specimens.
Safety Considerations: Material Safety Data (MSD) 

sheets are available from The Dow Chemical Company. MSD 

sheets are provided to help customers satisfy their own 

handling, safety, and disposal needs and those that may be

required by locally applicable health and safety regulations. 

MSD sheets are updated regularly, therefore, please request 

and review the most current MSD sheet before handling or 

using any product. These are available from the nearest Dow 

sales office.

Customer Notice: Dow encourages its customers to 

review their application of Dow products from the standpoint of 

human health and environmental quality. To help ensure that 

Dow products are not used in ways for which they were not 

intended or tested, Dow personnel will assist customers in 

dealing with ecological and products safety. Your Dow Sales 

representative can arrange the proper contacts.

NOTICE: The information and data contained herein do not constitute sales specifications. The product 

properties may be changed without notice No liability, warranty or guarantee of product performance is created by 

this document. It is the Buyer’s responsibility to determine whether Dow products are appropriate for Buyer’s use 

and to ensure that Buyer’s workplace and disposal practices are in compliance with applicable laws and 

regulations. No freedom from any patent owned by Seller or others is to be inferred.

C o n t a c t I n f o r m a t i o n : F o r m o r e i n f o r m a t i o n a b o u t P U S y s t e m s p r o d u c t s , 

c a l l T h e D o w C h e m i c a l C o m p a n y : h t t p : / / w w w . d o w . c o m / p u s y s t e m s / i n d e x . h t m

www.dow automo ti ve .com

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SPECFLEX NF 749 Polyol / Thermoset Systems