Note: Descriptions are shown in the official language in which they were submitted.
Z [)~3S3L34
THERMAL AND LIGHT STABLE FLAME RETARDANT THERMOPLASTIC
POLYOLEFIN AND POLYSTYRENE COMPOSITIONS
BACKGROUND OF THE INVENTION
Field of the Invention. This invention relates to
thermal and light stable ~lame retardant thermoplastic
polyolein and polystyrene compositions. More
particularly, this invention relates to thermoplastic
compositions which are flame retardant and which resist
thermal degradation or photochemically-induced
degradation. These compositions comprise bicyclic
phosphate compound(s); halogen-containing flame
retardant(s); and polystyrene or polyolefin resin.
The compositions produced in accordance with this
invention have a reduced tendency to develop color, to
change melt viscosity, or to lose mechanical strength
under conditions that are present during polymer
processing or end-use.
De~cri~tion of the Prior Art.
It ~s known in the art that polystyrene and
polyolefins, such as homopolymers and copolymers o
polypropylene, polyethylene, and polybutylene, may be
flame retarded with halogen-containing flame retardants.
Although efficient in suppressing the rate of
combustion in a resin ~ystem, mo~t flame retardants tend
to affect adversely one or more key properties of the
resin. For example, many flame retardant additives are
susceptible to thermal and photochemically-indu~ed
- ",- ,: . :
- . .
'. . : ~, , ';
3~
degradation during processing of the thermoplastic resin,
or during polymer u~e conditions.
Evidence of degradation may be seen in several Ways.
For example, the therm~plastic composition may develop ~
darkened appearance during processing, indicat~ng polymer
or flame retardant chemical decomposition; or ~he
thermoplastic composition may suffer an increase or
decrease in melt viscosity, limiting, for example, the
recycle of industrial scrap ("regrind") or environmental
plastic waste; or the thermoplastic composition may lose
mechanical strength, thus reducing the overall ~ervice
life of the polymeric material.
Many prior art references describe the use of
stabilizers, such as antioxidants, hindered phenols,
hindered amines, phosphites, and the like, in polystyrene
and polyolefins. A general treatise covering thi~ broad
: topic includes PolYmer Stabilization and Dearadation, ACS
SYmPOSiUm Series. No. 280, P.P. Klemchuk, ed., American
Chemical Society, Washington, D.C. (lg853.
However, the ~election of a suitable stabilizer for
polystyrene and polyolefin r~sins is not predictable.
Stabilizer selection is particularly diff~cult when flame
retardants are employedJ exacerbated by the complex
interaction between the polymer and the halogen-
containing compound.
Briti6h Patent No. 889,338 describes the production
of bicyclic phosphites, phosphonates, thiophosphates, and
selenophosphates. These compositions are ~aid to be
34
--3--
stabilizers for vinyl halide resins. They are alleged to
be useful as heat stabilizers for vinyl chloride resin,
and as antioxidants for fats and oils. The British '338
Patent does not ~how any examples of bicylic phosphate~,
5 nor does it specify the use of bicyclic phosphates, ~uch
as pentaerythritol-based bicyclic phosphates of the
present invention, which can be employed as a stabilizer
for polystyrene or polyolefin resin. Eurthermore, the
British '338 Patent does not disclose that cyclic
phosphates of the present invention could be used with
halogen-containing flame retardants to produce flame
retardant thermoplastic compositions which resis~ thermal
or photochemically-induced degradation.
British Patent No. 999,793 describes a process to
produce organic phosphates by subjecting organic
phosphites to reaction with peracetic acid. This patent
shows a method for producing the most preferred bicyclic
phosphate of the present invention, 2,6,7-trioxa-1-
phosphobicyclo[2.2.2]-octane-4-methanol-1-oxide (vide
infra), and teaches the use of acetal ring-containing
phosphates as plastisizer~ or functional fluid~. The
British '793 Patent, however, does not disclose the
composition6 of the present invention. It does not
mention bicylic pho~phates as being useful for flame
retardant thermoplastic resins, nor that the most preferred
bicyclic phosphate of the pre ent invention can be used
with halogen-containing flame retardant additives to yield
improved thermoplastic composition
~3~8Ç~3~
U.S. Patent No. 3,873 J 496 describes a flame retardant
polyester composition which contains 5 to 25 percent of a
hydroxymethyl bicyclic phosphate compound as a flame
retardant additive. The patentee did not observe the
ability of bicyclic phosphates to act as heat or melt
~tabilizers for thermoplastic resin compo ition~ ~hich
employ halogenated compounds as the primary flame
retardant additive.
U.S. Patent No. 4,341,694 discloses a composition
comprising 2,6,7-trioxa-1-phosphobicyclo[~.2.2]octane-
4-methanol-1-oxide and a nitrogen-containing co-additiveJ
which are intumescent and are adaptable to flame retard
polyolefins, polyvinylaromatic resins, polycaxbonates,
P~rC and blends thereof. The patentee did not observe any
stabilization of the present invention.
Accordingly, a primary objec~ of this invention i~
to provide thermal and light stable flame retardant
thermoplastic polyolefin and polystyrene compositions.
A related object is to provide compositions of the
character de~cribed which re8i8t thermal degradation or
photochemically induced degradation.
A further object i 8 to provide polyRtyrene or
polyolefin resin compositions incorporating bicyclic
phosphate compounds and halogenated flame retarda~t~.
SUMMARY OF 1~ INVENTION
The foregoing and other objects, advantages and
features o~ the present invention may be achievable wi~h
thermal and light stable thermoplastic polyolefin or
.
2~:36~3~
polystyrene resin compositions incorporating an additive
mixture comprising a halogen-containing flame retardant;
and a bicyclic phosphate compound of ~he the following
Formula (I):
s
O R
O=P ''' ~ CH
( ) X
where X is OH, OR', or OC(O)R'; R is H or a satur2ted or
unsaturated ~traight-chain or branched-chain Cl-C17
alkyl; and R' is a saturated or unsaturated
straight-chain or branched chain Cl-C17 alkyl.
DESCRIPTION OF THE PREEERRED EMBODIMENTS
This invention relates to thermal and light stable
flame retardant theremoplastic polyolefin and poly~tyrene
compositions. In particular, the invention xelate~ to
thermopla~tic polyolefin and polystyrene resin
composition5 which are flame retardant and which re~i3t
thermal degradation or photochemically induced
degradation and which incorporate an additiYe mi~ture
comprising one or more bicyclic pho~phate compound~ and
one or moxe halogen-containing 1ame retardant~.
Compositions produced in accordance with this invention
3~
have a reduced tendency to develop color, to chanye melt
viscosity, or to lose mechanical ~trength under conditions
present during polymer processing or in use.
Preferred bicyclic phosphates in accordance with ~his
invention are compounds of Formula (I) where X is ~H or
OC(O)R'. The most preferred bicyclic compounds are
2,6,7-trioxa-phosphobicyclo[2.2.2]-octane-4-methanol-1-
oxide (Compound BCP, that is, Formula lI] when R is H and
X is OH), and 2,6,7-trioxa-1-phosphobicyclo[2.2.2]-
octane-4-methanol, acetate, 1-oxide (Compound BCP-A, that
is, when R i~ H and X is OC(O)CH3).
The halogen-containing flame retardant compound may
be any brominated or chlorinated aliphatic or aromatic
oryanic compound that can be used in thermoplastic
compositions. Preferred halogen-containing compounds are
hexabromocyclododecane, tetrabromobisphenol A,
- tetrabromobisphenol A bis-(dibromopropylether),
dibromo(dibromoethyl)cyclohexane, tetrabromocyclooctane J
bi 8- ~ dibromonorbornane dicarboximido)ethane,
bis-(tetrabromophthalimido)ethane, Diels-Alder adduct of
chlorinated cyclopentadiene and unsaturated
cycloaliphatic compound, bis-(tribromophenoxy-
ethyl)tetrabromobisphenol A ether, pentabromodiphenyl
ether, o~tabromodiphenyl ethar, decabromodiphenyl ether,
bis-(tribromophenoxy)ethane, bis-(pentabromo-
phenoxy) thane, chloropentabromocyclohexane,
~tribromophenoxy)-(dibromononylphenoxy)ethane J
pentabromoethylbenzene, pentabromododecylbenzene,
3~
carbonate oligomers of tetrabromobisphenol A,
poly(brominated styrene), and brominated polystyrene,
poly(brominated phenylene) ether, and mixtures thereof.
These halogenated compounds are added to thermoplastic
resins at levels such that the resultant resin composi-
tion may be rendered flame retardant.
Resin~ which may be treated in accordance with the
invention include thermoplastics such as polystyrene and
copolymers sf styrene with butadiene and acrylonitrile
("ABS copolymers") and homopolymers and copolymers of
polyolefins such as polypropylene, polyethylene, and
polybutylene. Polystyrene and polypropylene are
preferred thermoplastics in accordance with this
invention.
The polystyrene may be any thermoplastic
polystyrene, especially impact modified grades, as
described in Modern Plastics EncYclopedia, Vol. 63, No.
lOA, 74 (1986), or grades suitable for making ~oamed
products. Preferably, the additives of the invention are
used With impact grades classiied by notched impact
values between 0.6 and 3.0 ft-lb/in, and most preferably
between 1.0 and 2.5 ft-lb/in.
The polypropylene may be any thermoplastic
polypropylene, especially homopolymer type, ~s de~cribed
in Modern Plastics EncycloPedia, Vol. 63, No. lOA, 72
(1986)J or grades suitable for making foamed products.
Preferably, the additives of thiC i~vention are u~ed with
grades cla~sified by melt flows between 2 and 30 g/10
3~
min., and most preferably between 4 and 10 g/}0 mln.
The compo itions of this invention al60 desirably
incorporate one or more enhancing agents. Enhancing
asent~ useful in accordance with this invention comprise
the oxides and halides of groups IV-A and V-A of the
periodic table; organic or inorganic compounds of
phosphorus, nitrogen, boron sr sul~ur; and oxides and
halides of, for example, zinc, magnesium and titanium,
all as disclosed in U.S. Patent No. 4,016,139.
Preferred enhancing agents in accordance with thi~
invention are the oxides of antimony, ar~enic and bismuth,
with the oxides of antimony being especially preferred.
Antimony trioxide i~ the most preferred enchancing agent
used in the compositions of ~his invention.
~he compositions of this invention may additionally
incorporate one or more antioxidant~, hindered amine light
stabilizers, or acid scavengers. Especially preferred
antioxidant is 2,2-bi 8 [ 13-[3,5-bi~(l,l-dimethylethyl)-
4-hydroxyphenyl]-1- oxopropoxy]methyll1,3-propanediyl
3,5,-bis~l,1-dimethylethyl~-4-hydroxybenzenepropanoate;
e~pecially preferred hindered amine light stabilizer i~
bi~(2,2,6,6-tetramethyl-4-piperidinyl)-sebecate; and
especially preferrsd acid ~cavenger i~ magne~it~m aluminum
hydroxy carbonate Mg4 5A12(0H~13C03-
The ~cope of ~he present invention includes ~he
incorporation of other additives in the composition B0 far
as to produce a particular end re~ult. Such additives
include, without limitation, blowing agents, heat
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stabilizers, light stabilizer6, plasticizer~, pigments,
preservatives, ultraviolet light 6tabilizer6, filler~,
antioxidants, antistatic agents and other materials well
known to those 6killed in the art, for example, a~
5 de~cribed in Modern Plastics EncYcloPedia. Vol. 63, No.
lOA, Mc~raw-Hill, Inc. (1986).
The bicyclic phosphates of the present invention may
be u~ed alone or as mixtures of any such compounds. When
mixtures of bicyclic phosphates are employed,
substantially any combinations of amounts and proportions
of the individual compounds may be used. The u~e of
Compound BCP and Compound BCP-A is especially preferred
in accordance with this inventionO
The halogen-containing flame retardants of the
present invention may be used alone or as mixtures of any
such compounds. When mixtures of halogen-containing
: phosphates are employed, substantially any combinations
of amounts and proportions of the individual compound~
may be u~ed. The use of hexabromocyclododecane,
tetrabromobisphenol A, chloropentabromocyclohexane,
tetrabromobi~phenol A bis-~dibromopropylether),
dibromo(dibromoethyl)cyclohexane, tetrabromocyclooctane,
bi~-(dibromonorbornane dicarboximido~ethane, and
Diel~-Alder adduct of hexachlorocyclopentadiene Gnd
cyclooctadiene i~ especially preferred in accordance with
thi~ invention.
Desirably, the bicyclic phosphate compound and
3~
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halogen-containing flame retardant are provided as a
mixture useful as an additive which may be added to
polystyrene or polyolein resin compositions. The
additive mixture utilize~ bicyclic phosphate in
halogen-containing flame retardant in a weight ratio
lying in the ran~e of about 0.001 to 0.200, most
preferably, about 0.005 to 0.050.
~ he additive mixture is in~orporated into the
polymer composition at a level such that the resulting
resin composition i8 rendered flame retardant. In
general, the additive mixture i~ provided in the flame
retardant at a level of about 0.1 - 20.0 percent by weight
of the resin composition, preferably about Q.5 - 20.0
percent by weight.
Practice of the present invention is illustrated by
the following example~.
EXAMPLES
The following examples are given to illustrate the
invention and ~hould not be construed a6 limiting its
scope. All percentages are by weight. The t~rm
polystyrene refers to polystyrene ava~lable from Hunt~man
Chem~cal Corporation as PS 3037; the term polypropylene
refers to polypropylene available from ~imont Chemical
Company a~ Profax 6301; and the term acrylonitrile-
butadiene-styrene refer~ to acrylonitrile-butadiene-
styrene available from Borg Warner Corporation a~ Cycolac
GSM 1000. All flame retardant compo~itions received a
V-2 or V-0 ratin~ as mea~-ured by ~he UL-94 te~t.
.
,, ~
13~
TABLE I contain~ examples which illustrate the
effectiveness of bicyclic phosphate compound and
halogen-containing flame retardant in polypropylene re~in
to minimi~e a change in polymer melt viscosity during
processing.
05 The thermoplastic compo~itions were compounded in a
3/4" single screw extruder (L/D 25:1) at 43Q F. The
extrudate was pelletized and re-extruded ten time~. The
melt viscosity of the final extrudate was measur~d by a
melt flow technique.
EXAMPLES 1-2 and COMPARATIVE EXAMPLES 1-2
Examples 1-2 are flame retardant polypropylene
compositions containing 4.0% hexabromocyclododecane (Flame
Retardant HBCD), available under the trademark CD-75P
from Great Lakes Chemical Corporation, and, respectively,
0.1% and 0.2% 2,6,7-trioxa-1-phosphobicyclol2.2.2
octane-4-methanol-1-oxide (Compound BCP).
Comparative Example 1 shows the inherent melt
vi~cosity of a non-flame retardant polypropylene
composition which has be~n aub~ected to multiple
extrusions. Comparative Example 2 shows ~hat Elame
Retardant HBCD has a detrimental effect on polymer melt
vi~cosity, as evidenced by an increase in melt flow from
29.3 g~10 min (Comparative Example 1) to 77.1 g~10 min
(Comparative Example 2~.
Surprisingly, when Compound BCP i~ added to the
composition, the damaging effect~ of Flame Retardant ~BCD
on the melt viscosity of polypropylene re~in are reduced.
`
13~ ,
-12-
Example 1 and Example 2 show less change in melt flow than
Comparative Example 2.
EXAMPLES 3-4 and COMPARATIVE EXAMæLES 3-4
Examples 3-4 are flame retardant polypropylene
composition~ containing 0.1% hindered p~enolic
antioxidant (Compound A0), which i8 available from
Ciba-Geigy Corporation as Irganox 1010, and 0.1% acid
scavenger (Compound AS), which is available from Kyowa
Chemical Industry as DHT-4A, respectively.
Examples 3-4 and Comparative Examples 3-4 in TABLE I
illustrate also the utility of Compound BCP to inhibit
changes in polymer melt viscosity when other additives
are present in the thermoplastic resin. Example 3 ~hows
the effectiveness of Compound BCP in the presence of a
hindered phenolic antioxidant, and Example 4 6hows the
effectiveness of Compound BCP in the presence o~ an acid
6cavenger.
TABLI; I
FLAME RETARDANT OTHER ADDITIVE ~ELT FLOW
BCP gllO min
EXAMPLE ADDITIVE TYPE AMOUNT. TYPE ~MOUNT ASTM
NUMBERweight X weight % wsight X D-1238
_
O.1 HBCD 4.0 ~ 66.6
CONP 1 0.0 -- --~ 29.3
COMP 2 0.0 HBCD 4.0 -- --- 77.1
2 0.2 HBCD 4,0 -- --- 70.7
2~3G~3~
TABLE I (CONT.)
FLAME RETARDANT OTHER ADDITIVE MELT FLOW
~CP - gllO min
EXAMPLE ADDITIVE TYPE AMOUNT TYPE AMOUNT A~TM ,
NUMBERweight X weight % weight X D-1238
3 0.1 HBCD 4.0 AO 0.1 13.3
COMP 3 0.0 HBCD 4.0 AO 0.1 75.2
4 0.1 HBCD 4.0 AS --- 38.2
COMP 4 0.0 HBCD 4.0 AS 0.1 40.6
_
Note: Polypropylen~ resin, 430F.
TABLE II contains examples which illustrate the
effectiveness of the preferred bicyclic phosphate compound
and HBCD in polystyrene resin to minimi~e a change in
polymer melt viscosity during processing.
EXAMPLE 5 and COMPARATIVE EXAMPLES 5-6
Example 5 is a ~lame retardant polystyrene formulation
in accordance with this invention containin~ 0.1% Compound
BCP and 2.0% Flame Retardant HBCD.
Example 5 illustrates an improvement in melt low over
Comparative Example 5 and Comparative ~5~ample ~. l~u8,
Compound BCP is effective in poly~tyrene when no additional
additives are present (Comparative Example 5) or when an
acid scavenger is present (Co~nparative Example 6).
.
2~ 3~
T~BLE I I
FLAME RET~RDANT OT}ER ~DDITIVE MELT ~LOW
BCP 8/10 ~in
EXAMPLE I~DDITIVE TYP~AMOUNT TYPE QMOUNT ASTM
NUNBERwa~ht % wel~ ht X wel~ht X D-1238
0.1 HBCD2.0 -- --- 15.8
10 COMP 5O. O HBCD2. 0 -- --- >~0
CO~P 6O. O H~CD2. 0 AS 0.1 22.1
_ _ _
Nota: Polystyrene resin, 500F.
TABLE III show~ compositions of the present ~nvention
which have less tendency to degrade thermally in various
polymer systems.
Thermal degradation was measured by formulating
compositions in a Brabender Plasticorder mixer (Model
PL-V300) for 21 minutes, 50-70 rpm, and at the temper-
atures as specified in TABLE III, Footnote 1. The polymer
melt was sampled at three minute intervals, and vi~ual
inspections of the appearance of the polymer composition
ware made.
The color and description of the formulated
composition~ are listed ~n Table III, and reflect the
appearance of the composition when either the material
showed total degradation ~that is, developed a black or
dark red color or showed signs of decompo~ition, such a8
off-gassing), or when the 21 minute inter~al of the te~t
was attained.
2~ 3~
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EXAMPLES 6-10 and COMPARATIVE EXAMPLES 7-lZ
Examples 6-~ are flame retardant polystyrene
compositions containing 0.2% Compound BCP and 4.0%,
respectively, Flame Retardant B CD; dibromo(dibromoethyl)
cyclohexane (Elame Retardant TBCH), available from ~thyl
Corporation as BCL-462; Diel~-Alder adduct of
hexachlorocyclopentadiene an~ cyclooctadiene (Elame
Retardant CBCO), available from Occidental Corporation
as Dechlorane Plus; and monochloropentabromocyclohexane
(Flame Retardant CBCH), available from Dow Chemical
Corporation as FR-651.
Example 10 is a flame retardant polystyrene
composition containing 0.8% Compound BCP and 16.0%
tetrabromobisphenol A (Flame Retardant TBBP), a~ailable
from Great Lakes Chemical Corporation as BA-59P.
Examples 6-10, as supported by comparisons to
Comparative Examples 8-12 (specified in Table III)
illustrate polystyrene compositions which resist ~hermal
degradation and h~ve less tendency to develop color under
processing conditions. Comparative Example 7 shows the
inherent color development of non-flame retardant
polystyrene resin which has been ~ub~ected to the te~t
procedures .
Examples 6-10 illustrate al50 that Compound BCP i~
effective in the pre3ence of various halogen-conta~ning
flame retardant additives.
EXAMPLE 11
Example 11 is a flame retardant poly~tyrene com~o-
. .
:
-16-
sition containing 0.2% acetate derivative of Compound BCP
(designated Compound BCP-A) and 4.0% Flame Retardant
HBCD. Example 11 i8 an illustration of a bicyclic pho~-
phate other than Compound BCP which ~ 8 within the scope
of this ~nvention.
EXAMPLE 12 and COMPARATIVE EXAMPLES 13-14
Example 12 iB a ~lame retardant acrylonitrile-butadiene-
~tyrene ("ABS") composition containing 0.5% Compou~d BCP,
4.0% Sb20~, and 16.0% Flame Retardant TBBP.
Example 12, as supported by comparison to Comparative
10 Examples 14 (specified in Table III), i8 an illustration
of utility of the present invention in ~BS resin.
Comparative Example 13 shows the inherent color develop-
ment of non-flame retardant ABS resin which has been
subjected to the test procedure~.
EXAMPLES 13-14 and COMæARATIVE EXAMPLES 15-17
Examples 13-14 are flame retardant polypropylene
composition~ containing 0.5% Compound BCP, 1.0% Sb203,
and, respectively, 3.0% tetrabromobisphenol A bi~(dibromo-
propylether) (Flame Retardant TBPE) and 5.0% Flame
Retardant HBCD.
Example~ 13-14, a~ supported ~y comparison to
Comparative Examples 16-17 (specified in Table III),
illustrate the e~fectivene~ of the present invention to
reduce the tendency ~or di6coloratlon in flame retardant
polypropylene compo~itions. Comparative Example 15 hows
the i~herent color development of non-flame retardant
polypropylene resin which has been ~ubjected to ~he te~t
procedures.
2 ~ 3
-17-
TABLE III
-
FLAME RETARDANT
5 BCP
EXAMPLE ADDITIVE RESI~ TYPE AMOUNT 2
NUMBER weight % TYPE weight X COLOR DESCRIPTION
6 0.2 A HBCD 4.0 0 IRANSPARENT
COMP 7 O.D A ~ O TRANSPARENT
COMP 8 0.0 A HBCD 4.0 10 OPAQUE
7 0.2 A TBCH 4.0 2 TRANSPARENT
COMP 9 0.0 A TBCH 4.0 10 OPAQUE
8 0.2 A CBCO 4.0 0 OPAQOE
COMP 10 0.0 A CBCO 4.0 3 OPAQUE
9 0.2 A CBCH 4.0 4 OPAQUE
COMP 11 0.0 A CBCN 4.0 10 OPAQUE
0.8 A TBBP 16.0 2 OPAQUE
COMP 12 0.0 A TBBP 16.0 8 OPAQUE
11 0.2 A HBCD 4.0 2 TRANSPARENT
12 0.5 B TBBP 16.0 5 OPAQUE
25 COMP 13 0.O B -- --- 1 OPAQUE
COMP 14 0.0 B TBBP 16.0 8 OPAQUE
13 0.5 C TBPE 3.0 6 OPAQUE
COMP 15 0.O C -~ 1 OPAQUE
COMP 16 0.0 C TBPE 3.0 10 OPAQUE
14 0.5 C HBCD 5.0 1 OPAQUE
COMP 17 0.O C HBCD 5.0 10 OPAQUE
NOTE 1: A) Polystyrene resin, 450F; B) Acrylonitrilebut~diene-
styrene resln, 4.0X Sb203, 500F; C) Polypropylene, 1.0% Sb203,
NOT~ 2: O~colorless; l=white; 2=light yellow; 3=yellow; 4=dark
yellow; 5=light tan; 6=tan; 7=dark tan; 8-brown; 9=dark brown;
10=black, red or decomposed.
3 L~
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TABLE IV ~hows polypropylen~ compositions of the
present invention which have less tendency to lose
mechanical strength, when such compositions are exposed
to radi Ati on.
Thermoplastic compositions were compounded and
injection molded into test specimens, m~asuring 5.0~
x 0.5" x 0.062n. The ends of the test specimens were
clamped together, placed in an Xenon Arc Weatherometer
(Atlas Model Ci-35), and irradiated according to ASTM
D-4459 procedures for 3000 hours. The te~t ~pecimens
were observed periodically for signs of cracks or
crazing. The time at which failure occured was noted.
EXAMPLES 15-16 and COMPARATIVE EXAMPLES 18-19
Examples 15-16 are flame retardant polypropylene
compositions containing 0.5% Compound BCP, 10.0% Flame
Retardant TBPE, 3.3% Sb203, and~ respectively, 0.5%
hindered amine light stabilizer (Compound HALS), available
from Ciba-Geigy Corporation as TIN W IN 770, and O.5%
20 Compound AS.
Examples 15-16, as supported by comparison to
Comparative Examples 18-19 (specified ~n Table IV) J
illu~trate the effectiveness of the present invention
to reduce the tendency for photochemically-induced
mechanical failure in flame retardant polypropylene
composition~.
.
2~
--19--
TABLE IV
FLA~ RETARD~NT OTHEP~ ~DDITIVE
TIME TO
~CP STRESS
EX~MPLE ~DDITIV~; TYPl; ~MOI)NT TYPE ~MOI~NT FAILURE
Nl)MBER wei~ht % wei~ht X weight X hours
-
0 . 5 TBPE 10 . O }~LS O . 5 2900
10 CONP 18 0 . O TBPE 10 . O }~LS 0. 5 2500
16 0 . 5 TBPE 10 . O AS O . 5 ~3000
COMP 19 0 . O TBPE 10 . 0 AS O . 5 - 150
Polypropylene resln and 3. 3% Sb203.
TABLE V shows polypropylene composition~ of ~he
present invention which have less tendency to discolor,
when such compositions are exposed to radiation.
ThermoplasticR compositions were compounded,
injection molded into 3.0" x 1.0" x 0.125'~ test specimen~,
and irradiated in a Xenon Arc Weatherometer ~Atlas Model
- Ci-35), according to ASTM D-44~9 procedure~ for 2000 hours.
Changes in color were measured as Delta E values, accord-
ing to ASTM-2244 procedures.
EXAMPLES 17-20 and COMPARATIVE EXAMPLES 20-22
Example~ 17-18 ar~ 1nme retardant polypropylene
compositions containing 3.3% Sb2O3, 10.0~ Flame Retardant
TBPE, andJ respectively, 1.0% BCP Compou~d and 0.5%
Compound BCP.
Examples 19-20 are ~lame retardant polypropylene
compositions containin~ 0.~% Compound BCP, 10.0% Flame
' ' ,- . ` - -': .. .
-
:, - .
. ~ :
... . ., . ,,
2~)~6~3~
-20-
Retardant TBPE, and, respectively, 0.5% hinder2d amine
light ~tabilizer Compound HALS and 0.5% alkytin-containing
stabilizer (Compound TLS), available from Witco Chemical
Company as Mark 1413.
Example~ 17-20, as supported by comparison ts
Comparative Example~ 20-22 (~pecified in Table V~ J
lllustrate the effectivenes~ of ~he present invention to
reduce the tendency for photochemically-induced
discoloration in flame retardant polypropylene composi-
tions.
TABLE V
_
FLAME RETARDANT OTH~R ~DDITIVE
COLOR
BCP LIGHT
EXAMPLE ADDITIVE TYPE AMOUNT TYPE AMOUNT STABILITY
N~MBER weight % weight X weight X Delta E
17 1.0 TBPE 10.0 -.- --- 4.90
18 0.5 TBPE 10.0 --^ --- 4.08
COMP 20 0.0 TBPE 10.0 --- --- 7.90
19 0.5 TBPE lO.O HALS O.5 2.03
COMP 21 0.0 TBPE 10.0 HALS 0.5 4.05
0.5 TBPE 10.0 TLS 0.5 3.02
CO~P 22 0.O TBRE 10.0 TIS O.5 5.27
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Polypropylene resin and 3.3X Sb203.
