The Effects of Various Additive Components on the Sound Absorption Performances of Polyurethane Foams

Table 3

Main components and properties of the foam.

Main component	Group 1	Group 2	Group 3	Group 4
	(parts by weight)	(parts by weight)	(parts by weight)	(parts by weight)
3630	28	28	28	28
330N	52	52	52	52
MDI	28.8	28.8	28.8	28.8
Catalyst A33	0.9	0.9	0.9	0.9
Catalyst A1	0.04	0.04	0.04	0.04
Silicone	0.9	0.9	0.9	0.9
TEA	1.0	1.0	1.0	1.0
Water	3.8	4.1	4.4	4.7
Density (kg/m^3)	80.2	71.8	69.9	64.0
Airflow resistivity	18,600	15,400	14,600	11,300
Porosity	74	77	83	89