Integral polyprene 233

Polyprene 233 has been designed for the production of Semirigid Integral Skin foams with molded density of 200-500 kg/m³ and skin hardness of 40-70 Shore A. It is suitable for the production of steering wheels as well as armrests at medium density. A-Polyprene-233-7021 Polyol provides graphite coloured foam (RAL 7021).

Typical Component Properties

	Units	A-233 -7021 Polyol	B-233 Isocyanate
OH number	mg KOH/g	183	-
H₂O content	%	0.12	-
NCO content	%	-	28.5
Viscosity, 25°C	cps	1000	120
Specific Gravity, 25°C	g/cm³	1.03	1.22

Recommended Process Conditions

Polyol ingredient may separate in different layers, therefore each drum must be properly mixed before use.
HCFC-141b used as a blowing agent must be premixed in polyol component before processing in amount of (8-12)% by weight.
Although isocyanate component is a stable liquid at 15°C, it does crystallize below this temperature. The recommended technique for melting crystallized material is drum heating at 60-70°C for no more than 24 hours.
Moulds must be treated with a proper release agent.

	Units	Values
A-233-7021 Polyol (including HCFC-141b)	pbw	100
B-233 Isocyanate	pbw	46 – 50
Components temperature	°C	25 – 28
Typical moulds temperature	°C	45 – 60
Demoulding time	min	~2*

*Depends on the mould’s construction.

Typical Reaction Characteristics

	Units	Hand-mix*
Ratio	Polyol (10% of HCFC-141b)/Iso	100:50
Cream time	s	14 – 20
Gel time	s	27 – 40
Rise time	s	38 – 55
Free rise density	kg/m³	140 – 200

*Data referred to laboratory tests made with Isocyanate component at 24°C and Polyol component at 24°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 according to the procedure described in the Recommended Process Conditions paragraph.

	Units	A-233-7021 Polyol	B-233 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
Overall density range	kg/m³	200 - 500
Tensile strength	kPa	850 (core) 4000 (skin)
Elongation	%	90 (core) 100 (skin)
Tear	N/m	3 (core) 7 (skin)
Compression set (50%, 70°C, 22 h)	%	9
Hardness	Shore A	55 - 65

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