Flexible polyprene 238

Polyprene 238 belong to a new Cold Cure MDI fully water blown system generation with a final moulded density of 45-60 kg/m³. The product is designed for shot demoulding time, very wide foam load bearing latitude, very high and long components (Iso and Polyol) stability: no recycling or mixing is needed. It is suitable for multi pouring technology and dual hardness technology (varying the Iso/Polyol ratio). It is recommended for the production of large and small mouldings, especially for automotive cushion and back rest applications.

Typical Component Properties

	Units	A-238 Polyol	B-238 Isocyanate
OH number	mg KOH/g	43.2	-
NCO content	%	-	29.0
Viscosity, 25°C	cps	1075	65
Specific Gravity, 25°C	g/cm³	1.02	1.21

Recommended Process Conditions

	Units	Values
A-238 Polyol	pbw	100
B-238 Isocyanate	pbw	53 – 68
Components temperature	°C	20 – 24
Typical moulds temperature	°C	45 – 55
Demoulding time	min	4 – 6*

*Depends on Polyol/Iso mixing ratio.

Typical Reaction Characteristics

	Units	Hand-mix*
Ratio	Polyol/Iso	100:61
Cream time	s	14 - 20
Gel time	s	70 – 85
Free rise density	kg/m³	33 - 38

*Data referred to laboratory tests made with Isocyanate component at 20°C and Polyol component at 20°C, hand-mixed with mechanical stirrer at 3000 rpm. Reported values vary depending on processing conditions.

Handling and Storage

The Iso component must be stored in liquid state. In case of crystallization it has to be melted heating the drum at 60-70°C for no more than 24 hours.

	Units	A-238 Polyol	B-238 Isocyanate
Storage temperature	°C	15 - 25	15 – 25
Shelf life	months	6	6

Typical Polymer Properties

These items are provided as general information only.

	Units
Core density	kg/m³	50
Compressive strength (40%)	kPa	7.0
Tensile strength	kPa	130
Elongation	%	100
Tear	N/m	210
Compression set (50%, 70°C, 22 h)	%	4.3
Resilience (Ball rebound)	%	62

pass to the list of systems of flexible polyurethane