Flame retardant performance of various UL94 classified materials exposed to external ignition sources

Abstract

SUMMARYThe flammability of eight halogen-free styrene resins and one halogen-containing styrene resin was characterized by UL 94 VB, LOI and cone calorimeter tests. Their burning behaviour was also measured when exposed to three external ignition sources (methenamine tablet, candle, paper ball). Five resins were used for 19 00 monitor housings and the others for 25 00 TV. The LOI values of UL 94 V-2, V-1 and V-0 rated resins were higher than that of HB. The heat release rate decreased as the UL 94 ratings increased from HB to V-0. When these resins were exposed to three external ignition sources, UL 94 V-1 and V-0 rated resins showed a self-extinguishing property after removal of the fire and did not cause fire growth in either 19 00 monitor or the 25 00 TV housings in all cases. However, UL 94 V-2 and HB rated resins were easily ignited and spread fire by dripping burning trickles. The burning rate of V-2 resin was slower than that of HB.

Correlations between pyrolysis combustion flow calorimetry and conventional flammability tests with halogen‐free flame retardant polyolefin compounds

“…The ground calcium carbonate (CaCO 3 ) was coated with stearic acid, and had an average particle size of 3.5 m (HI-PFLEX 100 from Specialty Minerals Inc.). The magnesium hydroxide (Mg(OH) 2 ) was a precipitated grade with an average particle size of 1.8 m (Vertex 60 from Huber). The nanoclay was a synthetic organo-magadiite prepared as described in Patent Cooperation Treaty Application Serial No.…”

“…In addition, theoretical char yields are included for two cases. In both the cases, the theoretical char yields assume silicone is converted to silica, ATH to Al 2 O 3 , Mg(OH) 2 to MgO, polymer to gaseous products, organomagadiite to inorganic magadiite. The two scenarios used to calculate theoretical char residue values shown in Figure 9 are: scenario (1) assuming that the CaCO 3 did not get hot enough to decompose, and scenario (2) assuming that the CaCO 3 was converted to CaO.…”

Steady heat release rate by the moment–area method

“…While and f ( ) are experimental data, and must be computed using Equations (3) and (4). In the following, we define characteristic values of the dependent variable (density function) from the area and moments of its history (distribution).…”

“…The specimens used for fire calorimetry tests are rarely thick enough to exhibit steady-state burning; hence, the only time-invariant HRR obtained from these typically thin and intermediate thickness specimens is the maximum/peak HRR and the test-average HRR. It is well known that the peak HRR of plastics measured in fire calorimeters under forced combustion correlates poorly with flame/ignition resistance [4,5]. However, steady HRR correlates flame retardancy [5,6] and is linked to combustion properties by a physical model [7,8].…”

Full-scale flammability measures for electronic equipment

“…The flammability of fire retarded (FR) styrene resins was studied in the context of monitor and TV housings [15]. UL94, Cone Calorimeter and limited oxygen index (LOI) benchscale data were compared to the qualitative burning of the housings when exposed to three different ignition n sources.…”