Chapter 5
Chlorinated Flame Retardant Used in Combination with Other Flame Retardants R. L. Markezich and D. G. Aschbacher Technology Center, Occidental Chemical Corporation, Grand Island, NY 14072
Polyolefins and ABS can be flame retarded using a mixture of a chlorinated and brominated flame retardants. There is a synergistic effect that allows flame retardant levels to be lowered, resulting in improved physical properties and lower cost formulations. The chlorinated flame retardant used is CFR, the Diels-Alder diadduct of hexachlorocyclopentadiene and 1,5cyclooctadiene. Several different brominated flame retardants have been used which all show the same synergistic effect. Polyolefins wire and cable formulations can also be flame retarded using a mixture of the same chlorinated flame retardant and inorganic salts, such as magnesium hydroxide. The mixture of these two flame retardants show a synergist effect in the oxygen index test. These formulations give less smoke when tested in the NBS smoke chamber. Using alumina trihydrate instead of magnesium hydroxide does not show a synergistic effect. The synergistic action between antimony oxide and halogenated flame retardants is well known . Not as well known is the synergistic action between chlorinated and brominated flame retardants to impart flame retardants properties to plastics. In 1970, R. F. Cleave reported a synergistic effect between an aliphatic chlorine compound and an aromatic bromine compound in the presence of antimony oxide. Mixtures of pentabromotoluene, chlorinated paraffins, and antimony oxide appear to be more efficient than mixtures of any two alone. It 1
2
0097-6156/95/0599-0065$12.00/0 © 1995 American Chemical Society
FIRE AND POLYMERS II
does indicate that some degree of synergism exists between the two halogens when in combination with antimony oxide. In 1976, Gordon, Duffy, and Dachs reported on the use of mixtures of the chlorinated flame retardant (CFR) and decabromodiphenyl oxide (DBDPO) to flame retard ABS. A more recent patent to Ilardo and Scharf* covers the use of mixtures of chlorinated and brominated flame retardants in polyolefins. The use of poly(tribromophenylene oxide) (BR-PPO) with the chlorinated flame retardant, CFR, gives a maximum oxygen index at 1:1 mixture of the chloro and brominated flame retardant. Figure 1 is a plot of some of the data from the patent; a FR-low density polyethylene formulation using a mixture of halogens with antimony oxide shows a maximum oxygen index at 15% of CFR and 15% BRPPO. We have extended the work on ABS and investigated several different brominated flame retardants with the chlorinated flame retardant CFR. 3
Materials and Procedures The additives used are listed in Table I. The ABS (acrylonitrilebutadiene-styrene) resins used in these evaluations were from commercial sources. The resins were dry blended with the additives, extruded using a twin-screw extruder, pelletized, dried, and then molded into test bars. The E V A (ethylene vinyl acetate copolymer, 9% vinyl acetate) resins were also from commercial sources. The experimental samples were mixed on a two-roll mill to obtain a homogeneous sample. Compounded polymer samples were sheeted and granulated prior to molding. Testing Oxygen Index (OX) The test employed is the ASTM D2863. UL 94. The Underwriters Laboratories vertical flame test. Notched Izod. Izod impact resistance (ASTM D256). HDT. Heat Deflection Temperature (ASTM D648). Smoke Generation. Testing was performed in a NBS Smoke Chamber according to ASTM E-662. The samples, 3 by 3 inch by 0.085 inch thick were exposed to radiant heat plus propane microburners (flaming combustion). Smoke evolution was continually recorded during the test period. Results are reported as specific optimal density, Ds.
MARKEZICH & ASCHBACHER
A Chlorinated Flame Retardant
Table I. Materials and Sources Abbrev.
Chemical Structure
Trade Name
Source
CFR
Diels-Alder adduct of hexachlorocyclopentadiene and 1,5 cyclooctadiene
Dechlorane Plus®
Occidental Chemical Corporation
CFR-2
Same chlorinated flame retardant but with a mean particle size of less than 2 microns
Dechlorane Plus®
Occidental Chemical Corporation
BFR-1
Brominated epoxy resin with 51% Br
YDB-406
Tohto Kasei
BFR-2
Bis(tribromophenoxy) ethane (70% Br)
FF680
Great Lakes
Antimony Oxide MgOH
Thermo-guard®S AtoChem Magnesium hydroxide
Talc
Zerogen®35
Solem Division of JMHuber Corp.
Mistron ZSC
Cyprus Industrial Minerals
Antioxidant
Agerite Resin D R. T. Vanderbilt
Peroxide
Luperox 500R
AtoChem
FIRE AND POLYMERS II
Results FR-ABS Table II gives several FR-ABS formulations using a mixture of chloro and bromo flame retardants. The oxygen indexes from the formulations in this table are plotted in Figure 2. The highest oxygen index is obtained when there is a 1:1 mixture of chlorine and bromine from the flame retardants (Formulation #3). This is also the only formulation that is UL-94 V-0 at both 3.2mm and 1.6mm. Table III shows the results of using different amounts of antimony oxide with a 1:1 mixture of CI and Br, total halogen 11%, in the formulations. Table IV shows the results with 10% total halogen, 1:1 mixture of CI and Br. It appears from a plot of this data, Figure 3, that a maximum oxygen index is reached at about 8% antimony oxide with 11% halogen and 6% antimony oxide with 10% halogen. Results FR-W&C Table V gives some typical talc filled FR wire and cable formulations using CFR as the flame retardant in combination with magnesium hydroxide. The total flame retardant level is constant at 25% with 5% Sb 0 . Figure 4 shows a graph of the % MgOH versus oxygen index. There is a synergistic effect between the chlorinated flame retardant and magnesium hydroxide which gives the highest O.I. with 20% CFR and 5% MgOH. The use of alumina trihydrate, instead of magnesium hydroxide, in these talc filled E V A W&C formulations, which are cross linked, does not show the same synergistic effect as MgOH does (shown in Figure 5). Table VI shows FR-EVA formulations that do not contain talc. The oxygen indexes of these formulations are shown in Figure 6. There is a maximum oxygen index when the mixture contains 5 to 10% MgOH with 5% Sb O . The NBS smoke generation data for some of the F R - E V A formulation is shown in Table VII. As can be seen, the mixed CFR/MgOH (15:10) formulation gives lower smoke values than CFR alone (3# versus #1). The use of 0.1% F e 0 with CFR also gives a reduction in smoke, but not as much as the mixed CFR/MgOH system. 2
3
2
s
2
3
MARKEZICH & ASCHBACHER
A Chlorinated Flame Retardant
34
0
5
10
15
20
25
30
%CFR Figure 1
Oxygen Index of FR-LDPE 30% Total Halogen CFR minus % BR-PPO 32
251
! 100
! 75
! 50
! 25
%CI Figure 2
Oxygen Index of FR-ABS 11% Total Halogen/CFR-2 minus BFR-1
L 0
FIRE AND POLYMERS II
28.9
%MgOH Figure 4
Oxygen Index of FR-EVA 20% Talc/5% Sb 0 /25% CFR Minus % MgOH 2
3
MARKEZICH & ASCHBACHER
A Chlorinated Flame Retardant
Table II. FR-ABS Formulations 1
2
3
4
5
ABS
78.1
76.8
75.55
74.28
73
CFR-2
16.9
12.7
8.45
4.22
5
5
5
5
-
~
5.5
11
16.5
22
Sb 0 2
3
BFR-1
5
Results O.I.
25.75
28.25
31.25
28.25
27.25
UI^94 3.2mm 1.6mm
V-0 NC
V-0 NC
V-0 V-0
V-0 NC
V-0 NC
Notched Izod J/M
64
82
87
107
97
% CI
11
8.2
5.5
2.7
% Br
-
2.8
5.5
8.4
11
11
11
11
11
4
5
Total Halogen %
11
Table III. FR-ABS Formulations 1 2 3
-
ABS
81.7
79.9
77.6
75.7
73.7
CFR-2
8.45
8.45
8.45
8.45
8.45
2
4
6.1
8
10
7.85
7.85
7.85
7.85
7.85
24.25
26.75
30.75
31.25
29.25
UI^94 3.2mm
NC
V-l
V-0
V-0
V-0
Notched Izod J/M
174
160
136
120
105
HDT deg C Annealed 24 hours/80 deg
95
96
94
96
95
% α
5.5
5.5
5.5
5.5
5.5
% Br
5.5
5.5
5.5
5.5
5.5
Total Halogen %
11
11
11
11
11
Sb 0 2
3
BFR-2
Results O.I.
FIRE AND POLYMERS II
Weight %
Table IV: FR-ABS Formulation 1 3 2
4
5
ABS
83.2
81.2
79.2
77.2
75.2
CFR-2
7.7
7.7
7.7
7.7
7.7
2
4
6
8
10
7.1
7.1
7.1
7.1
7.1
Sb 0 2
3
BFR-2
Results 24.25
25.75
28.25
28.25
28.25
UI^94 3.2mm
NC
NC
V-0
V-0
V-0
Notched Izod J/M
200
175
157
136
114
% CI
5.0
5.5
5.5
5.5
5.5
% Br
5.0
5.5
5.5
5.5
5.5
Total Halogen %
10
10
10
10
10
O.I.
Table V: FR-W&C Formulations 1
2
3
4
5
EVA
47.9
47.9
47.9
47.9
47.9
CFR
25
20
15
10
5
5
5
5
5
5
MgOH
0
5
10
15
20
Talc
20
20
20
20
20
Agerite Resin D
1.4
1.4
1.4
1.4
1.4
Luperox 500R
0.7
0.7
0.7
0.7
0.7
Weight %
Sb 0 2
3
Results O.I. (%)
28.1
28.75
28.41
27.42
27.25
% Elongation
350
320
300
190
140
MARKEZICH & ASCHBACHER
A Chlorinated Flame Retardant
29.5
25.51
0
1
1
1
I
2
4
6
8
I
I
10 12
I
I
14
16
I
L
18 20
% MgOH or ΑΤΗ Figure 5
Oxygen Index of FR-EVA 20% Talc/5% Sb 0 /25% CFR Minus % Α Τ Η or MgOH 2
3
26
0
2
4
6
8
10 12
14
16
18 20
%MgOH Figure 6
Oxygen Index of FR-EVA 30% CFR Minus % MgOH
22
24
26 28
FIRE AND POLYMERS II
Table VI: FR-EVA W&C Formulation (No Talc) Weight % 2 1 EVA
67.9
62.9
CFR
30 to 5
30 to 5
0
5
0to25
0to25
Agerite Resin D
1.4
1.4
Luperox 500R
0.7
0.7
Sb 0 2
3
MgOH
Table VII: Smoke Generation of FR-EVA 20% Talc Filled Formations (E-662) (Flaming Mode) 1
2
3
4
25
25
15
15
5
5
5
5
MgOH
-
-
10
10
Fe 0
-
0.1
-
0.1
CFR Sb 0 2
2
3
3
Results Ds 4
11
4
15
4 Min.
247
233
108
128
Max.
416
395
309
277
Time to Max. (Min.)
9.8
9.8
10.2
11.5
1.5 Min.
5.
MARKEZICH & ASCHBACHER
A Chlorinated Flame Retardant
Conclusions ABS resins can be flame retarded using a mixture of chlorinated and brominated flame retardants. There is a synergistic effect between chlorinated and brominated flame retardants, which can result in lower flame retardant levels needed to achieve flame retardancy. Flame retarded wire and cable formulations using a mixture of a chlorinated flame retardant and magnesium hydroxide show a synergistic effect in the oxygen index flammability test and produces less smoke when burned. References 1. 2. 3. 4. RECEIVED
I. Touval, Plastics Compounding, September/October, 1992. R. F. Cleaves, Plast. Polym. 38 (135) 190, 1970. I. Gordon, J. J. Duffy, and N . W. Dachs, US Patent 4,000,114 (1976). C. S. Ilardo and D. J. Scharf, US Patent 4,388,429 (1983). April 28,
1995
