Note: Descriptions are shown in the official language in which they were submitted.
535
~C~-225
The present invention relates to
flame retardant thermoplastic cornpositions
comprising a normally ~lammab]e thermoplastic
resin or resins and a phosphorus/nitrogen
(P-N) bond-containing flame retardant agent.
The compositions possess good flame resistance
with superior retention of other physical
properties, especially heat distortion tem~
perature, in comparison with similar com-
positions wherein a non-nitrogen bond-containing
phosphorus material is used to impart flame
; retardancy.
The use of thermop]astic xesins in
the Eormation of shaped articles by the use
of molding techniques e.g., compression molding,
extrusion, blow molding, and the like, is well
known to those skilled in the art. Depending
on the choice of thermoplastic resins, shaped
articles having high impact strength, stiffness,
good surface appearance, heat resistance and
other desirable properties during or after
molding are providedO
By way of illustration, thermoplastic
LS35
~3CI~-22
mo]ding resins include polypheny]ene ethers,
along or wi-th styrene resins, as we7] as others
well kno-~n to those skillecl in the art.
A major shortcoming in the use of
such thermoplastic resins is their normal]y
flammable nature. Thus, for applications where
flame retardancy is desirable, such as in the
fields of home construction, automobile and
aircraft manufacture, packaging, electrical
equipment, furniture, upholstery and the like,
flame retardant and/or drip retardant agents are
commonly incorporated into the resin or composi-
tions containing the resin before molcling.
The flammability of normally flammable
thermoplastic polymers has been reduced in the
prior art by using antimony-, halogen-, phosphorus-
or nitrocJen containing additives, commonly
referred to as flame retardant agents, and such
compositions are described in various patents
and publications. For example, aroma-tic phos-
phates, e.g., triphenyl phosphate, either
unmodified or synergistically combined
with other compounds such as halo-
-- 2 --
11;~1535
~C II- 2 2 5 5
1 genated aromatics~ have been added as flame retardant agents
- 2 to polyphenylene ether compositions. See, e.g., Haaf, U.S.
3 3,639,506 and Canadian Application Serial No.291.790 , filed
4 November 25, 1977, and assigned to the same assignee as herein.
These phosphate compounds impart good flame resistance properties
6 to the thermoplastic blend without detracting from physical
7 properties, except for a tendency to reduce heat distortion
8 temperature. Hexaalkylphosphoric triamides are known to stabilize
9 thermoplastics against degradation by heat and oxygen, See Holoch,
U.S. 3,414,536 and Holoc~, Raynor and Haaf, U.S. 3,483,271.
11
12 It has now been surprisingly discovered tha~ com-
13 pounds having aromatic or heterocyclic or alicyclic substituents
14 and a phorphorus-nitrogen bond system provide excellent flame
retardant properties when added to normally flammable thermo-
16 plastic resins or blends of such resins.
17 .
18 In comparison with the phosphate compounds used as
19 flame retardant addltives in~the prior art, the materials of
this invention, on a weight for weight basis, have been found
21 to exhibit comparable performance as flame retardant agents.
22 But, unexpected improvements in other properties are obtained,
23 such as a reduced tendency to undergo heat distortion and the
24 capacity for decreased smoke production during burning. For
example in a polyphenylene ether/polystyrene composition, tri-
26 phenyl phosphate effects a 4.3F./pbw reduction in heat distor-
27 tion temperature as compared with only 2.3F./pbw of phosphoryl
2~ trimorpholide.
l~lS~S 8CH-2255
In addition to being useful by themselves, the new compositions are
useful in compositions with other resins and elastomers to improve flame
retardancy.
Description oE the Invention - Accordingly, the present invention,
in its broadest aspects, provides a flame retardant thermoplastic composition
which comprises, in admixture:
ta) a normally flammable thermoplastic resin or resins; and
tb) from greater than 10 to about 30 parts per hundred resin of
a phosphorus/nitrogen flame retardant agent seleeted from the formulae
t i) [X~
wherein each X is independently seleeted from:
ta) a nitrogen or a nitrogen-oxygen interrupted heterocycloaliphatie
ring; and, R2
tb) \ N - , wherein R is an aryl radieal of from 6 to 12
R3~
carbon atoms and R is selected from hydrogen, monovalent lower alkyl radicals,
cyeloalkylene diamine, arylene diamine or carbonyl thiocarbonyl; and,
O O
tii) [X ~ P ~ Y ~ P ~ [X]2
wherein X is as defined above and Y is seleeted from a divalent dioxyarylene
of from 6 to 18 earbon atoms and a eompound of the formula-N\__/N -; and,
tiii) including r 7eatlng unlts having the formula
~ P - T -
~ O
where Z is selected from
~ and 0
and T is selected from
N N - and - NHR NH -
4 ~
wherein R is arylene, a earbonyl radical or a thioearbonyl radical.
~ - 4 -
~ . 11;~1535
8(:H-2255
1 The term "normally flammable" as used herein,
describes c~mpositions which do not meet the V-l requirements
3 of the Unde~riters' Laboratories Bulletin No. 94 test.
. In a preferred embodiment, the P-N flame retardant
6 agent ~r is selected from compounds of the formulae:
'7
8 ~ O
~ ~
2 (ii)
13 ~ ~ ~
14 ~ ~ P - X -- P --t )
1~;
17 wherein ~ is
18.
19 ~ l~3 ~
~ ~ 0
21 CH3
22
23 or
24
~5 ~
26 N N
28
. .- 5 - ` .
8CM--225'~
1~ 1535
1~iii) a compound comprising repeating units ~;L
2the formulae:
3 [~3
6 ~ ~ P -- N N
8 or
12 ~ ~N~
14 ¦ ~ r -- . N N
8 ..
19 (iv)
2 3 ( ~ NR7~ P
24 where R7 is H or a (lower) alkyl, e . g . Cl-C6 alkyl; and
2~ . .
29
~ -6-
5 3S 8C~1-2255
l (v) a compound comprising repeating units of
2 th formul~
6 ~ 3
8 wherein R5 is arylene, - C = O or - C = S.
9 .
Preferably, flame retardant agent 4~ will be comprised
ll of the formula:
14 ( O ~ ~ 1l
18 The P-N compounds can be prepared by techniques which
19 are well known in the art and described in the literatu.e.
In general, such materials can be prepared by reacting a P-N
21` ,iprecursor with a mono- or diamine, or a urea or thiourea
22 and, if desired, with a dihydric phenol, e.g., bisphenol A, etc.
23
24 By way of illustration, the phosphory] trimorpholide
can be produced by reacting a phosphous compound, e.g., phos-
26 phorus oxychloride with morpholine at an elevated temperature,
27 e.g., from about-100 to about 200C. An acid binding agent
28 can be-employed, too.
2~
Typical pathways to obtain the other compounds of
31 interest a-e as follows: ;
53S
I Ç~Cri--~! 2 '~
o=~_z~o
.~,
o=~ o ~ z~
(o~ ~z~ 7 o r~
/ \ ~ O~Z_ _ o ~
~ 1 I o ~ û P~ E
~ Z
l ¦ ~ E ~ D
C + ~ + ~ c .,
o ,C,~ + a C,~ O
~ __
~ 535 ~CH-2255
The amount of P~N compound used as flame retardant
component is not critical, so long as it is present in a minor,
effective amount based on the weight of the resinous components --
major proportions may detract from physical properties. In
general, amounts of from greater than 10 to about 30 parts by
weight, preferably from greater than 10 to 15 parts of the flame
retardant per hundred parts resin are employed~
The present invention contemplates compositions
wherein the P-N flame retardant agent is used in combination
with any normally flammable thermoplastic resins having
at least the elements carbon, hydrogen and oxygen in its
structure. By way of illustration, with particular
reference to preferred thermoplastic materials, these include,
but are limited to, polyphenylene ether resins and styrene resins,
including mixtures of the foregoing.
The polyphenylene ether resin is preferably of the
type having the structural formula:
0 ~ (IV)
wherein the oxygen ether atom of one unit is connected to the
ben~ene nuc~eus of the next adjoining unit, q is a positive
integer and is at least 50, and each Q i~ a monovalent sub-
stituent selected from the group consisting of hydrogen,
~ 1535
~cl-2~5
1 halogen, hydrocarbon radicals free of a tertiary alpha-carbon
2 atom, halohydrocarbon radicals h~ving at least two carbon atoms
3 between the halogen atom and the phenyl nucleus, hydrocarbonoxy
radicals and halohydrocarbonoxy radicals having at least two
5 carbon atoms between the halogen atom and the phenyl nucleus.
7 A more preferred class of polyphenylene ether resins
8 for the compositions of this invention includes those of the
9 above formula wherein each Q is alkyl, most preferably, having
from 1 to 4 carbon atoms. Illustratively, members of this class
11 include poly~2,6-dimethyl-1,4-phenylene)ether; poly(2,6-diethyl-
12 1,4-phenylene)ether; poly(2 methyl-6-ethyl 1,4-phenylene~ether;
13 poly(2-methyl-6-propyl-1,4-phenylene)ether; poly(2,6-dipropyl-
14 1,4-phenylene)ether; poly(2-ethyl-6-propyl-1,4-phenylene)eth~r;
and the like.
16
17 Especially preferred is poly(2,6-dimethyl-1,4-phenyl-
18 ene)ether, preferably, having an intrinsic viscosity of about
19 0.45 deciliters per gram (dl./g.) as measured in chloroform at
3QC.
21
22 The preparation of the polyphenylene ether resins is
23 described in Hay, U.S. 3,306,874 and 3,306,375 and in Stamatoff,
24 U.S. 3 9 257,357 and 3,257,358, dated February 28, 1967 and
June 21, 1966, respectively.
26
27 The preferred styrene resins will be those h~ving at
28 least 25~/~ by weight of ~epeating units derived from a vinyl
29 aromatic ccmpound of the formula:
: 30
~_ .
~ 535 8CH-2255
R6C = CH2
~ (Z)p (V)
wherein R6 is hydrogen, (lower) alkyl or halogen; Z is vinyl,
hydrogen, halogen or (lower) alkyl; and p is O or an integer
of from 1 to 5. Herein, the term "(lower) alkyl" means alkyl
from 1 to 6 carbon atoms.
The term "styrene resins" is used broadly to define
components fully described in Cizek, U.S. 3,383,435.
Merely by way of illustration, such resins include
homopolymers, such as polystyrene, polychlorostyrene
and polyvinyl toluene, the modified polystyrenes such as rubber
modified polystyrene blended or grafted high impact products,
e.g., the rubber being a polybutadiene or an elastomeric copoly-
mer of styrene and a diene monomer. Also included are styrene
containing copolymers, such as styrene-acrylonitrile copolymers
(SAN), styrene-butadiene copolymers, styrene-acrylonitrile-
butadiene terpolymers (ABS), styrene-maleic anhydride copolymers,
polyalpha-methylstyrene, copolymers of ethyl vinyl benzene and
divinylbenzene, and the like.
Special mention is made of a preferred class of styrene
~0 containing resins. These are known as "~IPS" resins, for high
impact polystyrenes, in which the impact modifier comprises one
or more of an ethylene/propylene/diene terpolymer, or a hydro-
` I ~ 1535
8CEI-2255
l genated derivative, a vinylaFomatic/diene block copolymer resin,
or a hydrogenated derivative, a hydrogen saturated vinylaromatic/
3 diene random copolymer, a radial teleblock copolymer of a vinyl
4 aromatic compo~ld and a diene, a vinyl aromatic/methacrylic or
acrylic acid or ester/diene terpolymer, and the like. These
6 specialty HIPS resins are commercially available or can be pre-
7 pared by those skilled in this art.
The compositions of the invention can also further
include reinforcing agents, preferably fibrous glass reinforce-
11 men~s, alone or in combination with non-glass reinforcing
12 ¦ fillers. The fibrous glass is especially preferably fibrous
13 ¦ glass filaments comprised of lime-aluminum borosilicate glass
14 ¦ which is relatively soda free, known as "E" glass. However,
15 ¦ other glasses are useful where electrical properties are not
16 ¦ so important, e.g., the low soda glass know~ as "C" glass.
17 The filaments are made by standard processes, e.g., by steam
18 or air blowing, f:Lame blowing and mechanical pulling. The
19 preferred filaments for plastics reinforcement are made by
mechanical pulling. The filament diameters range from about
21 0.000112 to 0.00075 inch, but this is not critical to the
22 present invention.
23 .
24 In general, bes~ properties will be obtained if the
sized filamentous glass rei.nEorcements comprise from about 1
26 to about 80~/o by weight based on the combined weight of glass
27 and pol~mers and prefer2bly, from about 10 to about 50% by weight.
28 Especially preferably, the glass will comprise from about 10
29 to abou~ 40% by weight based on the combine~ weigh~ of giass
3C and resin. Generally, for direct molding ~se, up to about 50%
.
-12- 1
, . . - - ~
.,
` 8C~-2255
1 of glass can be present without causing flow problems. However,
2 it is useful also to prepare the compositions containing sub-
3 s'antially greater quantities, e.g~ up to 70 to 80% by weight
4 of glass. These concentrates can then be custom blended with
blends of resins that are not glass reinforced to provide any
6 desired glass content of a lower value.
8 Other ingredients, such as stabilizers, pigments,
9 plasticizers, antioxidants, and the like, can be added for
their conventionally employed purposes.
11
12 The manner in which the present compositions are
13 prepared is not critical and conventional methods can be employed.
14 Preferably, however, each of the ingredients is added as part of
a blend premix, and the latter is passed through an extruder, e.g.
16 e.g., a 28 mm. Werner Pfleiderer twin screw extruder, at an
17 extrusion temperature of from about 500 to about 600~F., depen-
18 dent on the needs of the particular composition. The strands
19 emerging from the extruder may be cooled, chopped into pellets
and molded to any desired shape.
21
22 Description of the Preferred Embodiments. - The
23 following examples are illustrative of the compositions of
24 this invention. They are not intended to limit the invention
in any manner. In the Examples, the compositions are made by
26 extrusion in a 28 mm. Werner Pfleiderer twin screw extruder, set
27 at the temperature and vacuum venting conditions specified. Mold-
28 ing is done on a 3 oz. NewburyTM machine set at the cylinder and
29 mold temperatures specified. The heat deflection temperature
(~F) is determined under 264 psi fiber stress on a 1/8" x 1/2i' x
31 2-1/2" specimen. The notched Izod impact strength ~ft.-lbs./in.
- 13 -
,
, ~ ~
: llZ1535
8C11-2255
1 notch) is determined on a 1/8" x 1/2" x 2-1/2" specimen. The
2 percent elongation, tensile strength at yield (psi) and tensile
3 strength at bxeak ~psi) are determined in 1/8" x 2-1/2" L-type
4 specimens. The self-extinguishing -- i.e., burning -- times for
specimens (dimensions indicated in Tables~ are determined-in
fi accordance with Underwriters Laborabories' Bulletin 94 procedures.
7 Gardner (i.e., drop-dart~ impact resistance (in.-lbs.) is deter-
8 mined on specimens of the size indicated. The poly (2,6-dimethyl-
1,4-phenylene)ether has an intrinsic viscosity of 0.48 dl./g. as
measured in chloroform at 30C.
1~ .
12 EXAMPLE 1
13 The following compositions are prepared in the extruder
14 at 575F with 25 in.-Hg vacuum venti~g. Molding is done at
530F (cylinder) and 190F. (mold). The molded pieces are tested
16 for physical properties and flame retardancy with results s~t
17 forth in Table 1:
29
21 .
22
~3
225 . ' . '
26
227
29
535 ~3CII- 2 2 5 5
I
U~ o
U~ U~ . . .. I , , I
U~ o O
.
-
o ~ o)
S~ C)
o ~ ~ ~o
~3~
a~ u u) O ~ ~ ' '~
~:: t~ Lr~ "-, . . . . , I ~ _ U
o a~ ¢ u~ 1~1 o o I I ~v ~
:~ ~ ~ . ~
P~
. ~ ~ o ~ ~ ~
G ,~: ~ h t~
0 0
` P~
U~ ~ o
. u~ O
-~ ~ 1 u~ ~~i ~ o o
cJ
~a O ~~d n
E~ c) ~ :~
~ ~ ô ~
` u E
I .~ a
:~ ~ ~ ~ a~ I o
. ~ c~ ~ ~ x&. ~ r~
U~ ~ ~4 U ~ ~1 ;-'
.~ u~
h u o
1--~ tll ,1~ 1 F. ~ p.~ O F-~
e~ & ~ U3 _ r~ a.)
;~ ~_ a) J U C~ O ~--/ ,.
~, ~ U ~1 ~ iJ V ~ h -J `1-
~C ~ ~ O ~ ~ r~) O
~ ~-.; I S~ U ~ I _ U
'D ~ ~ O C~
-~ ~ X O F. S~ C~ L~ X
~n c~J ~ JJ u U u~ o
o ~ C~
~ ~ CJ
a .~ O ,,
O O ~ O 0 1~ 1 .~ O h
C~ L ~ N `~ u I :~ ~ u
~:' .. ~
. - 15 -
I .
.
I 1~1535 8CH~2255
C~
J o o
h s~ o
. ~
, a' C~
o . o
-r_ ^o
a~
o~ `~
I ~D ~ ~ r~ ~ t~ O O
O O o
_ ......... c~J C~ GO ~ 00
o ~1
~ ~,~,
o ~ . C~l
~, , .
. ~ ~ .~
.
_
J~ CS~.
.` ~:
~_ ~ ' -~13
U~
~ I
O
.: ~ ,~ ~ o s~ o
C~ ' O O' I~
.. . ~ ~ r~
`_ ,1 `
G
C'~l~ , C~l~ ,
.
,~
' .C
U~
.,~
.1 ~ tq .
bO tO L~ -
,~ ' _ ~ o ~ .. _
V
X .~
~ ~ I n.CO
~
.
tO a~ - ~ JJ ~
tl~t.q : C~ O ~ ~
a~c) _ ~ .,
.,1~ . ~. ~ -
~ ~ ~ O t~
~~ ~n X ~ p,, ~ ~n o
o~ ~ tn ~ "~
~ a~
P~ ~ C~
:
d ~ ~
~ u
6-
~ 1535 8c~1-225s
1 EXAMPLE 2
2 The foliowing compositions are prepared in the extruder
3 at 570F. with 25 in.-Hg vacuum venting. Molding is done at
500F. (cylinder) and 190F. ~mold). The molded pieces are
tested for physic~l properties and flame retardancy, with
10 result set forth in Table 2:
18
2:1
.
26 ~ .
28 .
301 , '"
~ - 17 - I
~1~1535 :~3"T~1- 2 2 ~,
C~ ~ .~1 1 0
V~ ¢ U~ U~ .. . . ~ .
~ C~ ~ o o o
C~
~ . . .
.~
~ ~ o I
O
~ c~ O O O r~
. ~
.
.
.
~ ~ '
:. . C .~
O ~C ~
.b~
~ ra ~
E~ ~ ~ O O ~:
~d ,r - ~, ~ P.
. ~ _ ~
_l ~ ~ ~ ~ ~ .n
Q t~
~: r~ I ~ ~ ~ E~
.~ ^ ?~ X O 1: J~
tq ~ J ~ ~ o~ O ~ ~ 0 ~3
o ~ c~ u~
C~
~ ~ ~ ~ ~ ~ ~ o ~
O O O O
U ~ P.- ~ ~ N N 1::~, ~ t~l
- 1 8
~ 8CII--2255
11~1535
~ '
. ,
U~o
r~
. ~
o o
o C:~
~ 3 u~
¢ ~ ~1 0
c~ ~ ~ ~ ~ ~ r~
. I~
^r~ o o
.a~ o o
~1 C~ ~D O ~ 1--
' c~J ~ . U"~ ^ ^ ~D
~ C`~
CJ
. .
. . "
C~l ~ .
a)
,~
C ~
,~ ~ p ,~ ta
X
a)
I C~ E~ P
~ c~
,~
' G~
0 4~ JJ bO I
~ ~ X r~
a) E3
~1
P ~ ~ ~ O
E~ O ~ H U~ O
~ ~ U~
X
pl ~
O ~ c~ ~d O ~ ~ O
S I ~ a~ N t~
p ~
. I
l - 19 - I
11~15 35 8CH- 2 2 5 5
.'
1 EXAMPLE 3
. ~_
2 The following compositions are prepared in the
3 extruder at 580F. with 15 in.-Hg vacuum venting. Molding is
4 done at 550F. (cylinder) and 200F. (mold). The molded pieces
are tested for physical properties and flame retardancy, with
results se forth in Table ~:
18
21
27
29
. I
~C11-2255
1~1535
~ .
o
E~'
a~ o
U~ U~
o U~ U~
. ~o ~ ~ oc~
P~C~ ~ . o
Q~ ~
~ ~, .aJ
a) o a~ ~
P.~ ~ ~
g; ~ ~: o h
''~:. S Sa, ~ ' a~
~ ,a r~
~ ~1 ~ h O ~ ~
E~ ~ ~ 3S '~
. ~ g ~ O
~ I ~ a ~ ~ ~ ~
t~ ~~D h ~ ~ J-
X ,~~ X O ~:: ~ a
U~ ~ ~ ~ ~J U~ O ~ ~ ~ ,-
. O ~ 0~ C~ V~
~ ,~ ~
t:t,~ O~1
. O O O O Or~
C~ ~ P. ~ ~ N NP~ J-\ t~l ~
. , ~.
.
. '.
21 - .
_--, - . , , ~
C!I- 2 2 5 5
`;~ O O
o~ ~ o o
¢ I ~ ~ oo
I ~ O
C~
C`l~
. ~
~ o o
C~ ~ O O
~1 u
C`'t ` ' oo
~` Lt~
V~
. C~ . I
. . I
, . .
. .,
~1 ~
.~
E~ oo
' J- V ~ d
X
a~
I .
u a~
.
~q ~ g ~ hO
. ~ V ~
~3 ~ ~ : V 0 _ q,~
~d u, ~ ~ Cl. V h
~ a~ 4~ ~ ~v , ~ g
~ t~
~C I
cr~
ai ,~ - v r~ bO
' P~ . L~ ~ V ~
O ,~ I td O ~ . O
O~ N Q) r-l
. ~ -~ X W~
I
llZ:~535
8CT1-2255
1 It is no~eworthy that the composition eontaining
2 the phosphorus/ni~rogen bonded flame retardant agents, ~xamples
3 1 - 3 cause a smaller reduc~ion in heat distortion tempertures,
4 and generally superior retention of important physical proper-
ties, in eomparison with the conventional triphenyl phosphate-
6 containing composition lA 3A.
8 EXAMPLE 4
9 The relative smoke-producing characteristics of
phosphoruslnitrogen bonded flame retardants are compared ~ith
11 a conventional flame retardan~.
12
13 Two to three grams o triphenyl phosphate are placed
14 in an aluminum weighing dish. The dish is then placed under
a radiant panel such that the triphenyl phosphate is exposed
16 to the heat radiation. The temperature at the surface of the
17 triphenyl phosphate is estimated to about 300C. A lit Bunsen
18 burner is placed horizontally above and to ~he side of tne dish,
19 thus serving as an ignition source of whatever flammable vapors
will be évolved by the heating of the triphenyl phosphate.
21
22 After a matter of seconds, the triphenyl phosphate
23 melts, ignites1 and burns vigorously accompanied by ~he
24 evolution of copious quantities of black smoke.
26 The above experiment is repeated with tris (2-
27 carbamoyl ethyl) phosphine oxide and with pllosphoryl trimorpho-
28 lide. In both cases, as compared to that of triphenyl phosphate,
29 ignition requires a measurably greater amount of time, and
practically no smoke is evolved.
, i . . ~ .~ , ~ _ ~
~ llZ1535 RC~1-72SS
1 The results indicate that the non-aromatic natures of
2 the 2-carbomoylethyl and morpholide groups are highly beneficial
3 wlth respect to smoke reduction. 5uch non-aromatic compounds
thus provide a ~eans of formulating PPO/polystyrene/impact-
modifiers with fire-resistant and low-smoke characteristics.
It is to be understood, therefore, that these and
8 other modifications may be made in the particular embodiments
9 disclosed herein without departing from the scope o~ the inven-
13 tio R defined in ~hc appended cl~
7 . . .
19
~0
2~!
23
26
27
29
