Fire retardant blends

The instant invention provides a substantially flame retardant composition comprising: (a) a thermoplastic polyester and copolyester material, a halogenated organic fire retardant, antimony oxide, organo clay, and a fluorocarbon polymer. Also provided are compositions comprising glass fibers and stabilizers. The combination of the organo clay and the fluorocarbon polymer exhibits a synergistic effect on the fire retardant properties of the instantly claimed composition. This synergistic effect helps reduce the amount of the halogenated organic fire retardant in the instantly claimed flame retardant composition.

FIELD OF INVENTION 
This invention relates to novel flame retardant compositions comprising 
reduced amounts of halogenated fire retardant. 
BACKGROUND 
Different compositions have been studied and used as flame retardant 
materials, especially compositions comprising polymeric material. A 
typical composition generally comprises substantial amount of halogenated 
organic components having fire retarding properties. U.S Pat. No. 
4,582,866 discloses a fire retardant composition comprising flame 
retardant multi-block copolyester composition containing a bromine 
containing flame retardant. The brominated flame retardant constitutes 
from about 20 to about 30 percent of the flame retardant composition. 
U.S. Pat. No. 3,671,487 describes the use of halogenated flame retardants 
and phosphorus compounds to render the polyester non-burning or 
self-extinguishing, together with a polytetrafluoroethylene resin to 
render a non-dripping polyester resin. U.S. Pat. No. 4,344,878 describes 
the utilization of halogen containing polycarbonate mixed with antimony 
oxide together with polytetrafluoro ethylene. U.S. Pat. No. 5,554,674 
discloses a halogenated flame retardant absent an antimony containing 
synergist wherein the flame retardant enhancing additive is a metal acid 
pyrophosphate. 
Another publication that deals with flame retardant materials is EP 0 132 
228. This European Patent Application discloses a flame retardant 
reinforced polyester composition which contains a thermoplastic polyester, 
a reinforcing filler, an organic flame retardant material comprising a 
chlorine or bromine compound, alone or in combination with antimony oxide, 
a organically modified layered silicate, and a metal salt of a 6-22 carbon 
aliphatic acid. 
Halogenated flame retardants, especially bromine containing flame 
retardants are well known in the art and have been particularly successful 
as flame retardant additives. Most of these flame retardant compositions 
comprise either organo clays or fluorocarbon polymers, such as 
polytetrafluoroethylene (Teflon.RTM.), as an anti-dripping agent. However, 
because of the concern of the impact that bromine and other halogens might 
have on the environment, there is a definite need for flame retardant 
blends with reduced halogen content. It is thus the object of the instant 
invention to provide a flame retardant blend comprising a lesser amount of 
the halogenated component, preferably not more than 20% by weight of the 
total blend. 
SUMMARY OF THE INVENTION 
It has been surprisingly found that combination of organo clays and 
fluorocarbon polymers, as components of fire retardant blends that 
comprise thermoplastic polyester and copolyester materials, halogenated 
organic compound, and antimony oxide, exhibits a synergy that enables 
substantially lowering the amount of the halogen containing compound and 
also the amount of antimony oxide used in the fire retardant blend. 
The instant invention thus provides a substantially flame retardant 
composition comprising: (a) a thermoplastic polyester material comprising 
structural units of Formula I 
##STR1## 
wherein R represents a divalent hydrocarbon radical containing from about 
2 to about 20 carbon atoms, and Ar represents a C.sub.6 -C.sub.15 
substituted or unsubstituted divalent aromatic radical; (b) from about 5% 
to about 20% by weight of the thermoplastic polyester and copolyester 
composition of a halogenated organic fire retardant; (c) from about 1% to 
about 5% by weight of the thermoplastic polyester and copolyester 
composition of an antimony oxide; (d) from about 0.25% to about 5% by 
weight of the thermoplastic polyester and copolyester of an organo clay; 
and (e) from about 0.02% to about 2% of the thermoplastic polyester 
material of a fluorocarbon polymer. 
A second aspect of the instant invention provides another substantially 
fire retardant composition comprising: (a) a thermoplastic polyester 
material comprising structural units of Formula I 
##STR2## 
wherein R and Ar are as defined before; (b) from about 10% to about 30% by 
weight of the thermoplastic polyester material of fiber reinforcing 
material; (c) from about 0.1% to about 5% by weight of the thermoplastic 
material of stabilizers; (d) from about 5% to about 20% by weight of the 
thermoplastic polyester material of a halogenated organic fire retardant; 
(e) from about 0.1% to about 5% by weight of the thermoplastic polyester 
material of a antimony oxide; (f) from about 0.25% to about 5% by weight 
of the thermoplastic polyester material of an organo clay; and (g) from 
about 0.02% to about 2% by weight of the thermoplastic polyester material 
of a fluorocarbon polymer.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention is further defined through its preferred embodiments, 
wherein R represents a divalent hydrocarbon radical containing from 2 to 8 
carbon atoms. The preferred R groups are 1,2-ethylene; 1,3-propylene; and 
1,4-butylene. Another preferred embodiment provides a composition wherein 
Ar represents 
##STR3## 
The most preferred divalent aromatic radical is 
##STR4## 
Another preferred embodiment provides a composition wherein the 
thermoplastic polyester is poly(ethylene terephthalate), poly(propylene 
terephthalate), poly(butylene terephthalate), or poly(ethylene 
naphthalene-dicarboxylate), the most preferred polyester being 
poly(butylene terephthalate). Yet another preferred embodiment provides a 
composition wherein the organo clay comprises a organo cation exchanged 
layered silicate. A further preferred embodiment provides a composition 
wherein the antimony oxide is selected from antimony (mono)oxide, antimony 
trioxide, antimony tetraoxide, and antimony pentaoxide, with antimony 
trioxide being most preferred. 
The instant invention also provides another substantially fire retardant 
composition comprising: (a) a thermoplastic polyester material comprising 
structural units of Formula I 
##STR5## 
wherein R and Ar are as defined earlier; (b) from about 10% to about 30% 
by weight of the thermoplastic polyester material of fiber reinforcing 
material; (c) from about 0.1% to about 5% by weight of the thermoplastic 
material of stabilizers; (d) from about 5% to about 20% by weight of the 
thermoplastic polyester material of a halogenated organic fire retardant; 
(e) from about 0.1% to about 5% by weight of the thermoplastic polyester 
material of a antimony oxide; (f) from about 0.25% to about 5% by weight 
of the thermoplastic polyester material of an organo clay; and (g) from 
about 0.02% to about 2% by weight of the thermoplastic polyester material 
of a fluorocarbon polymer. 
The preferred divalent aromatic radical, Ar, is 
##STR6## 
The most preferred aromatic radicals are 
##STR7## 
Also provided is a preferred composition wherein R represents a hydrocarbon 
radical containing from about 2 to about 8 carbon atoms, the most 
preferred hydrocarbons being 1,2-ethylene; 1,3-propylene; and 
1,4-butylene. Preferred thermoplastic polyesters are poly(ethylene 
terephthalate), poly(propylene terephthalate), poly(butylene 
terephthalate), and poly(ethylene naphthalenedicarboxylate), with 
poly(butylene terephthalate) being the most preferred. Another preferred 
embodiment provides a composition wherein the organo clay is derived from 
layered silicates. Yet another preferred embodiment provides a composition 
wherein the antimony oxide is selected from antimony (mono) oxide, 
antimony trioxide, and antimony tetraoxide, with antimony trioxide being 
the most preferred antimony oxide. 
A preferred embodiment of the instant invention provides a composition 
wherein reinforcing materials include glass and carbon. The preferred 
composition comprises glass fibres from about 15% to about 30% by weight 
of the thermoplastic polyester and copolyester material. 
The preferred amount of the halogenated organic fire retardant additive 
comprises from about 8% to about 12% by weight of the thermoplastic 
polyester and copolyester material. Another preferred composition is one 
wherein the fluorocarbon polymer comprises from about 0.25% to about 1% by 
weight of the thermoplastic polyester and copolyester material. The 
specifically preferred fluorocarbon polymer is polytetrafluoro ethylene 
and its copolymers. A further preferred embodiment provides a composition 
wherein the polytetrafluoroethylene and its copolymer comprises from about 
0.04% to about 1% by weight of the thermoplastic polyester and copolyester 
material. 
One skilled in the art recognizes that different materials can be used as 
the components of the instant invention. The following discussion of the 
various components used will provide a description of some of the 
materials that make up the different components. The poly(butylene 
terephthalate) (PBT) used in the instant invention as a thermoplastic 
polyester has a high crystalline melting point, about 230.degree. C., 
along with a high degree and high rate of crystallization. Due to these 
characteristics, PBT is resistant to various solvents and chemicals while 
at the same time PBT can be injection molded at fast molding cycles 
thereby rendering superior properties to the molded parts and enhancing 
manufacturing productivity. 
The divalent radical R is a saturated divalent aliphatic or alicyclic 
hydrocarbon radical containing from about 2 to about 20 and usually about 
2-8 carbon atoms. The preferred alkyl portion for the terephthalates is 
1,2-ethylene; 1,3-propylene; or a 1,4-butylene. The most preferred 
polyesters are poly(ethylene terephthalate) ("PET"), poly(1,4-butylene 
terephthalate)("PBT"), poly(ethylene naphthalenedicarboxylate) ("PEN"), 
poly(propylene terephthalate) ("PPT"), poly(butylene 
naphthalene-dicarboxylate), ("PBN"), and mixtures thereof. It is however 
known that hydrocarbon groups represented by R may be substituted or 
unsubstituted with C.sub.1-6 alkyl groups or C.sub.4-10 cyclo alkyl 
groups. 
As defined herein, Ar represents a C.sub.6-15 divalent aromatic moiety, 
which is generally un-substituted, however substituted phenylene or 
naphthylene groups can be used. It is well known in the art that aromatic 
groups substituted with alkyl, cycloalkyl, aryl, araalkyl, halogen(s), 
phosphorous containing groups and, nitro and amino groups can be used as 
part of the thermoplastic polyester or copolyster structural backbone. The 
halogenated organic fire retardant falls in the broad category of 
halogenated hydrocarbons and halogenated polycarbonates, polyesters, and 
polyolefins. A detailed description can be found in Flammability Handbook 
for Plastics, Third Edition, by C. J. Hilado, which is incorporated herein 
by reference. The preferred fire retardants are selected from halogenated 
polycarbonates and their oligomers. 
The term antimony oxide as used herein includes antimony (mono)oxide, 
antimony trioxide, and antimony tetra oxide. The instant invention in one 
of its embodiment uses a phosphate containing component which comprises 
suitable inorganic phosphates. Typical inorganic phosphates are the alkali 
metal phosphates including ammonium phosphates, alkali metal hydrogen 
phosphates, and alkali metal pyrophosphates. 
As used herein, organoclay is a layered silicate clay, derived from layered 
minerals, in which organic structures have been chemically incorporated. 
Illustrative examples of organic structures are trimethyldodecylammonium 
ion and N,N'-didodecylimidazolium ion. Since the surfaces of clay layers, 
which have a lattice-like arrangement, are electrically charged, they are 
capable of binding organic ions. There is no limitation with respect to 
the layered minerals employed in this invention other than that they are 
capable of undergoing an ion exchange with the organic ions. The preferred 
organo clays are layered minerals that have undergone cation exchange with 
organo cations and/or onium compounds. Illustrative of such layered 
minerals are the kaolinite group and the montmorillonite group. It is also 
within the scope of this invention to employ minerals of the illite group 
which can include hydromicas, phengite, brammallite, glaucomite, 
celadonite and the like. Often, however, the preferred layered minerals 
include those often referred to as 2:1 layered silicate minerals like 
muscovite, vermiculite, saponite, hectorite and montmorillonite, wherein 
montmorillonite is often preferred. The layered minerals described above 
may be synthetically produced. However, most often they are naturally 
occurring and commercially available. A detailed description of the 
layered minerals can be found in U.S. Pat. No. 5,530,052 which is 
incorporated herein by reference. 
One embodiment of the instant invention uses glass fibers for reinforcing 
and other purposes. These glass fillers increase the strength and rigidity 
of molded parts. The glass fiber or filamentous glass is desirable, when 
employed as reinforcement in the present compositions. For compositions 
ultimately to be employed for electrical uses, it is preferred to use 
fibrous glass filaments comprised of lime-aluminum borosilicate glass that 
is relatively soda-free. This is known as "E" glass. However, other glass 
material are useful where electrical properties are not so important, 
e.g., the low soda glass known as "C" glass. The filaments are made by 
standard processes known to one skilled in the art, e.g., by steam or air 
blowing, flame blowing, and mechanical pulling. The preferred filaments 
for plastic reinforcement are made by mechanical pulling. 
The length of the glass filaments and whether or not they are bundled into 
fibers and the fibers bundled in turn to yarns, ropes or rovings, or woven 
into mats and the like are also not critical to the invention. However, in 
preparing the molding compositions it is convenient to use the filamentous 
glass in the form of chopped strands of from about 1/8" to about 2" long. 
In articles molded from the compositions on the other hand, even shorter 
lengths will be encountered because, during compounding considerable 
fragmentation will occur. 
Stabilizers, as used herein represent agents that deactivate ester 
interchange catalysts which are generally found in polyester resins. 
Illustrative examples include zinc phosphate and phosphoric acid. Other 
stabilizers such as photo stabilizers, antioxidants and the like can also 
be used in the compositions of the present invention. As used in the 
instant invention "fluorocarbon polymer" represents 
polytetrafluoroethylene and its copolymers. The term "thermoplastic 
polyester" includes polyester and copolyester materials. The fiber 
reinforcing material as used herein includes glass, carbon, and other 
reinforcing materials known to one skilled in the art. Other additives 
known to one skilled in the art can be added for cosmetic purposes. Thus 
one may add pigments to impart color to the fire retardant blend. 
The surprising finding that using a combination of an organo clay and a 
fluorocarbon polymer, such as polytetrafluoroethylene enables one to 
reduce the amount of the halogenated organic fire retardant, is 
illustrated by the following examples. The examples indicate that flame 
retardant blends that contain only one of organo clay or the fluorocarbon 
polymer do not possess the desirable flame retardant property. Thus, for 
example, a flame retardant blend (Example 3) that contains about 12% of 
the brominated organic fire retardant, by weight of the thermoplastic 
polyester material, along with the fluorocarbon polymer 
polytetrafluoroethylene (Teflon.RTM.) dispersion, but without the organo 
clay, fails the UL-94 test. Example 5 which contains 12% of the brominated 
organic fire retardant, by weight of the thermoplastic polyester material, 
along with an organo clay but without the Teflon.RTM. dispersion, fails 
the UL-94 test. However, if both the organo clay and the Teflon.RTM. 
dispersion are added to the blend (Example 4), it passes the UL-94 test. 
This indicates that a combination of the Teflon.RTM. dispersion and the 
organo clay is required for better fire retardant properties. The results 
are summarized in the tables that follow. 
EXPERIMENTAL DETAILS 
The instant invention is further illustrated by preparing control specimens 
and comparing their fire retardant properties with the fire retardant 
properties of new fire retardant formulations. The new fire retardant 
formulations were prepared by compounding mixtures of each component using 
a 20 mm counter rotating twin-screw extruder, followed by injection 
molding. Components BC-52 and BC-58 are brominated BPA polycarbonate 
oligomers available from Great Lakes Chemicals and have a bromine content 
of about 52% and 58% respectively. The T-SAN component is a 
polytetrafluoro ethylene (PTFE) dispersion in styrene acrylonitrile 
copolymer having over 50% PTFE content. The various other components of 
the present invention are summarized in Table 1. Most of the specimens 
used were 1/16" in thickness, 1/2" wide and 5" long. 
TABLE 1 
______________________________________ 
Component Component identity 
______________________________________ 
Translink 445 Surface modified wollastonite 
Na Montmorillonite (Na Mont.) 
Natural montmorillonite refined by soda 
ash treatment 
Mont./C.sub.12 H.sub.25 NH.sub.3.sup.+ 
Montmorillonite cation exchanged with 
dodecylammonium ion 
Mont./C.sub.16 H.sub.33 N.sup.+ (CH.sub.3).sub.3 
Montmorillonite cation exchanged with 
trimethyldodecylammonium ion. 
Mont./Im.sup.+ (C.sub.12 H.sub.25).sub.2 
Montmorillonite cation exchanged with 
N,N'-didodecylimidazolium ion. 
Mont./BI.sup.+ (C.sub.14 H.sub.29).sub.2 
Montmorillonite cation exchanged with 
N,N'-ditetradecylbenzimidazolium ion 
Claytone HY Montmorillonite cation exchanged with 
dimethyl di(hydrogenated 
tallow)ammonium ion. 
SCPX-896 Montmorillonite cation exchanged with 
methylbishydroxyethyl-(hydrogenated 
tallow)ammonium ion. 
Valox .RTM. 195 polybutylene terephthalate, (weight av. 
Mol. Wt (Mw) = 45,000) 
Valox .RTM. 315 polybutylene terephthalate, (weight av. 
Mol. Wt (Mw) = 105,000) 
Claytone APA Montmorillonite cation exchanged with 
triethylcetylammonium ion 
Sb.sub.2 O.sub.3 conc. 
About 85% Antimony oxide concentrate 
PETS pentaerythritol tetrastearate 
Irganox .RTM. 1076 
Octadecyl 3(3,5 di-t-butyl-4- 
hydroxyphenyl)propionate 
Zinc Phosphate (Zn Phos.) 
Zinc phosphate, ester-interchange 
inhibitor 
______________________________________ 
TABLE 2 
______________________________________ 
1 2 3 4 5 
Example No. 
wt % wt % wt % wt % wt % 
______________________________________ 
Valox .RTM. 315 
69.12 76.74 81.32 81.32 81.4 
BC-58 20 15 12 12 12 
Sb.sub.2 O.sub.3 Conc. 
10.5 7.88 6.3 6.3 6.3 
T-SAN 0.08 0.08 0.08 0.08 -- 
Zn phos. 0.3 0.3 0.3 0.3 0.3 
Organo clay 
none none none Claytone HY 
Claytone HY 
(% of PBT) 2 2 
UL-94 test 
V-0 V-0 F V-0 F 
Total flame out 
8.80 10.6 10.2 
time (sec) 
______________________________________ 
The examples in Table 2 above illustrate that using both the 
polytetrafluoroethylene (Teflon.RTM.) dispersion (T-SAN) and organo clay 
helps reduce the amount of the brominated compound (BC-58) necessary to 
achieve a V-0 rating in the UL-94 test. Thus in Example 2, 15% by weight 
of BC-58 is required to achieve a V-0 rating, and the composition of 
Example 3 which contains 12% by weight of BC-58, T-SAN, but does not 
contain any organo clay fails the UL-94 test. Similarly Example 5 shows 
that in the presence of organo clay and without T-SAN the formulation 
fails the UL-94 test. In contrast the composition of Example 4, which is 
the same as Example 3 and 5, except that it contains the organo clay 
achieves a V-0 rating. 
TABLE 3 
__________________________________________________________________________ 
6 7 8 9 10 11 12 13 14 15 
Example No. 
wt % 
wt % wt % wt % 
wt % 
wt % wt % wt % wt % wt % 
__________________________________________________________________________ 
Valox .RTM. 315 
84.45 
84.37 84.45 84.29 
84.21 
84.45 84.45 84.37 84.37 84.37 
BC-58 10 10 10 10 10 10 10 10 10 10 
Sb.sub.2 O.sub.3 conc. 
5.25 
5.25 5.25 5.25 
5.25 
5.25 5.25 5.25 5.25 5.25 
T-SAN 0.08 
0.08 -- 0.16 
0.24 
-- -- 0.08 0.08 0.08 
Zn phos. 
0.3 
0.3 0.3 0.3 
0.3 
0.3 0.3 0.3 0.3 0.3 
Organo Clay 
none 
Claytone HY 
Claytone HY 
none 
none 
Claytone HY 
Claytone HY 
Claytone HY 
Claytone HY 
Claytone HY 
(% of PBT) 
1 1 2 3 0.75 0.5 0.25 
UL-94 test 
F V-0 F F F F F V-0 V-0 V-0 
Flame out 15.9 15.9 
time (sec.) 
__________________________________________________________________________ 
The above examples, 6-12, indicate the synergistic effect of using both 
T-SAN and the organo clay. Thus Example 7, which comprises 10%, by weight, 
of the brominated fire retardant and, both T-SAN and the organo clay, has 
a V-0 rating, while Example 6 which comprises the same amount of BC-58 and 
T-SAN, as Example 7, but lacks the organo clay fail the UL-94 test. 
Further Examples 9 and 10 also fail the UL-94 test even if they contain 
twice and three times respectively of the amount of T-SAN compared to 
Example 7, but do not contain any organo clay. This is indicative of the 
synergistic effect observed by having both T-SAN and the organo clay in 
the fire retardant composition. Similarly Examples 11 and 12 also fail the 
UL-94 test even if they contain twice and three times the amount of the 
organo clay compared to Example 7, but do not contain any T-SAN. 
The synergistic effect is further evident from the UL-94 rating for the 
above Examples 13, 14, and 15 wherein their composition is the same as 
Example 7, but they respectively contain 0.75, 0.5, and 0.25% of the 
organo clay. This demonstrates the benefits of the synergistic effect of 
having both the T-SAN and the organo clay, even at reduced levels of the 
organo clay. 
TABLE 4 
__________________________________________________________________________ 
16 17 18 19 20 21 
Example No. 
wt % wt % wt % wt % wt % wt % 
__________________________________________________________________________ 
Valox .RTM. 315 
84.37 84.45 
84.37 
84.45 
84.37 
84.45 
BC-58 10 10 10 10 10 10 
Sb.sub.2 O.sub.3 Conc. 
5.25 5.25 5.25 5.25 5.25 5.25 
T-SAN 0.08 -- 0.08 -- 0.08 -- 
Zn phos. 
0.3 0.3 0.3 0.3 0.3 0.3 
Organo clay 
Claytone 
Claytone 
SCPX-896 
SCPX-896 
Mont./ 
Mont./ 
APA APA C.sub.12 NH.sub.3.sup.+ 
C.sub.12 NH.sub.3.sup.+ 
(% of PBT) 
2 2 2 2 2 2 
UL-94 test 
V-0 F V-0 F V-0 F 
Total flame out 
15.8 20.8 35.5 
time (sec.) 
__________________________________________________________________________ 
The above examples also illustrate the synergistic effect obtained by 
including T-SAN and the organo clay in the fire retardant blend whereby 
the blend exhibits enhanced fire retardant properties. As indicated by the 
above examples, fire retardant blends that include both T-SAN and the 
organo clay pass the UL-94 test (Examples 16, 18 and 20) while the others 
(Examples 17, 19 and 21) which do not include both T-SAN and the organo 
clay do not pass the UL-94 test. 
TABLE 5 
______________________________________ 
Example No. 22 23 24 25 26 27 
Component wt % wt % wt % wt % wt % wt % 
______________________________________ 
Valox .RTM. 315 
8 4.37 84.37 84.37 
84.37 84.37 
84.37 
Powder 
BC-58 1 10 10 10 10 10 10 
Sb.sub.2 O.sub.3 conc. 
5 5.25 5.25 5.25 5.25 5.25 5.25 
T-SAN 0.08 0.08 0.08 0.08 0.08 0.08 
Zinc Phos. 0.3 0.3 0.3 0.3 0.3 0.3 
Na Mont. 1.0 0.5 0.25 
(% of PBT) 
Translink 445 1.0 0.5 0.25 
(% of PBT) 
UL-94 F F F F F F 
Test 
______________________________________ 
Table 5 lists Examples that contain a natural clay, one of which (Na Mont.) 
is a precursor of the organo clay used in the present invention, while 
Translink 445 is a surface treated mineral filler. These examples 
illustrate that an organo clay is necessary to obtain the synergistic 
effect. Precursors of organo clays or surface treated naturally occurring 
clays do not afford the same effect, as indicated by the result that 
Examples 22-27 fail the UL-94 test. 
TABLE 6 
______________________________________ 
28 29 30 
Example No. wt. % wt. % wt. % 
______________________________________ 
Valox .RTM. 195 
35 35 35 
Valox .RTM. 315 
29.3 32.05 30.65 
10.mu. Glass Fiber 
17 17 17 
T-SAN 0.6 0.6 0.6 
Sb.sub.2 O.sub.3 conc. 
4.75 4.75 4.75 
BC-52 12.75 10 10 
Claytone HY -- -- 1.4 
PETS 0.2 0.2 0.2 
Zinc phos. 0.2 0.2 0.2 
Irganox .RTM. 1076 
0.2 0.2 0.2 
UL-94 Test V-0 V-1 V-0 
______________________________________ 
The examples in Table 6 above, contain glass fibers. Comparing Examples 29 
and 30, it can be seen that Example 30(which contains both the organo clay 
and the Teflon.RTM. dispersion) has a V-0 rating in the UL-94 test while 
Example 29 which does not contain the organo clay has a lower (V-1) UL-94 
rating. 
The UL-94 test is used to determine the fire retardant properties of 
materials. The test was used to determine the fire retardant properties of 
the various blends and the results were measured using a "V" value. Thus a 
V-0 value indicates superior fire retardant properties. A higher "V" value 
indicates inferior fire retardant properties. Thus materials classified as 
V-0 shall not have, among other things, any specimens which burn with 
flaming combustion for more than 10 seconds after application of the test 
flame, and not have a total flaming combustion time exceeding 50 seconds 
for the 10 flame applications for each set of five specimens. The Standard 
UL-94 test characteristics are determined according to the vertical 
burning test of the Underwriters Laboratories, Inc., 1980.