SPECFLEXTM NF 857 DA Polyol (LD821)

SPECFLEX NE 447 Isocyanate

Description

SPECFLEX NF 857 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. It is 

suitable for the production of automotive dual-hardness backrest as the 

hard side.

Typical Component Properties

Units SPECFLEX NF 

857 Polyol

SPECFLEX 

NE 447 

Isocyanate

Test Method

Viscosity, 25°C Mpa.s 2300-2400 (Lab 

Data)

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 857 Polyol pbw 100

SPECFLEX NE 447 

Isocyanate

pbw 39-50

Component Temperature 

(Pol/ISO)

°C 24-26

Typical Molds Temperature °C 60-65

Demolding Time Min 5-6

Typical Reaction Characteristics

Units

High 

Pressure 

Machine

Cream Time s 10-12

Rise Time s 70

Free Rise Density 

(Core)

kg/m3

31 

(Lab Data)

Handling and Storage

The Isocyanate component must be stored in liquid state. In case of 

crystallization, it has to be melted by heating the drum at 60-70 °C for 

no more than 24 hours.

Handling and Storage

Units SPECFLEX 

NF 857

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 

that recommended temperature protected from direct 

sunlight

Typical Polymer Properties

These items are provided as general information only.

Units Values Test 

Method 

Index 95 100 100 100 105 

Core density kg/m339.2 36.8 38.5 40.8 39.1 JIS K 6400 

Tensile 

strength kg/cm2 1.65 1.66 1.74 1.81 1.77 JIS K 6400 

Elongation % 110 110 105 105 103 JIS K 6400 

Tear Strength kgf/cm 0.57 0.6 0.59 0.6 0.58 JIS K 6400 

Ball 

Resilience % 68 68 68 68 68 JIS K 6400 

Dry set % 3.1 3.0 2.6 2.7 2.6 JIS K 6400 

Wet set % 10.5 11.2 10.2 10.1 10.1 JIS K 6400 

25% ILD kg/cm2 18.0 18.3 21.94 25.6 24.65 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)

MVSS 302 Pass

UNI CT 225 Pass

1. Numerical flame spread or fire classifications are only 

indicative; they are not sales specifications. These 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.

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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

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