Note: Descriptions are shown in the official language in which they were submitted.
8C~-2422
i7~ -
The present invention relates to flame retardant,
flexibili~ed thermoplastic polyphenylene ether composition.
The compositions of this invention comprise the poly-
phenylene ether, an aromatic phosphate and a thermoplastic
elastomer such as A-s-A block copolymer, e.g., poly-
styrene-polybutadiene-polystyrene, and optionally, a
halogenated hydrocarbon resin, alumina trihydrate and/or ;~
elemental red phosphorus.
The polyphenylene ether resins are well known in
the art as a class of thermoplastics which possess a
number of outstanding physical properties. They can be
prepared, in general, by oxidative and non-oxidative -~ ;
methods, such as are disclosed, for example, in Hay,
U.S. patent No. 3,306,874 dated February 28, 1967 and U.S.
3,306,875 dated February 28, 1967 and Stamatoff, U.S.
Patent No. 3,257,357 and 3,257,358 both dated June 21, 1966.
It is known that the polyphenylene ether resins alone
are somewhat difficult to fabricate because of their high
,.~
~3L~15r4~9
8CH-2422
temperature thermoplastic moldiny characteristics and this has
limited their use in applications where flexibility, such as
the need to calendar into relatively thin sheets, wlthout
cracking or crazing, is desirable.
In recent years, there has also been increasing concern
about the performance and safety of thermoplastic materials,
including the afore~mentioned polyphenylene ether com-
positions during real-life fire situation.
Of particular interest would be a polyphenylene ether
10 composition which is both flexibilized and flame retardant ;~ -
without loss of desirable properties.
It is known that flexible polyphenylene ether blends have ~-
been made with fairly high loadings of plasticizers. It has
now been found that the capabilities and alternatives in
making such blends can be greatly expanded by incorporating
rubber in the form of a block copolymer into such blends, and
further that if the flexlbilizer is predominately an aromatic
~ 2 ~
!¦ 8CH-2422
~ 5 7 ~
l phosphate, good self-extinguishing properties are obtained.
3 ~ased on the foregoing discovery, it has also
4 been found possible to further modifiy the blends to make them
somewhat less cos~ly, without loss of other beneficial proper-
6 tiPs, by replacing some of the aromatic phosphate with a
7 halogenated hydrocarbon resin, e.g., chlorinated paraffin.
8 Complete replacement of the aromatic phosphate is not possible,
9 however, without loss of flame resistance.
ll Furthermore, based on the foregoing discovery,
12 it has also been found possible to decrease the cost of the
13 formulation, without introducing a halogen source, and at the
14 same time, improve the self-extinguishing properties. This
lS discovery comprises including alurnina trihydrate in the composi-
16 tion.
17 . .
18 Finally, based on the foregoing discovery, it has
19 also been found possible to use higher levels of thermoplas~ic
elastomer without disruptin~ flame retardant properties and still
21 keeping a halogen-free system by the addition to the composition
22 of elemental red phosphorus~
23
24 In addition to being useful by themselves, the new
compositions are useful in blends with other resins and elasto-
26 mers to improve 1ame retardancy. Of course, conventional
27 additives such as pi~nents, fillers, stabilizers, and the like,
29 can be used with the new compositions of this invention.
.
3_
~ ~ , ~
. , .~s ~ ?, ; . - ~ ~
GE-45( 3L~lO~LS~3i ~CH-2422
1 Description of the Invention.- Accordingly, ~he
2 pre~ent ~n~en~ r~1 des Ln ~ts ~ro~de~ a~pe~t~, a flame
3 retardant flexibilized thermoplastic composition which comprises,
4 in admixture:
(a) a normally flammable polyphenylene ether
6 resin;
7 (b) a flame retardant aromatic phosphate plasticizer
8 in an amount at least sufficient to provide a flexibilized
composition after molding; and
(c) a thermoplastic elastomer comprising an A-B-A ;
11 block copolymer wherein terminal blocks A and Al are polymeric
12 units of a vinyl aromatic compound and center block B is a
13 polymer of a conjugated diene.
14
As employed herein, the term "flexibilized" is
~ 16 used in its art-recognized sense to clefine compositions which
; 17 are calenderable into relatively thin sheets, e.g., 1/4 inch ;~
18 or less in thickness, which can be bent without causing cracking
19 or crazing. Such thermoplastic compositions are suitable,
2p in appropriately thin forms, for products such as shower curtains
21 wall coverlngs, automotive upholstery, and the like.
22
23 The term "normally flammable" as used herein, des-
24 cribes compositions which do not meet the V-O and V-l require-
ments of the Underwriters' Laboratories Bulletin No. 94 tes~.
26
27 In a preferred feature, the new compositions will
2~ also include: ~ -
29 (d) a minor propOrtiOn of flame retardant
halogenated plasticizer based on the amount of aromatic phosphate
- 4 -
V~ ' ''''~
!¦ 8CH-2422
j~-45~
~ p~ne~t (b). Especially preferred halogenated hydroc~rb~ns
2 are chlorinated paraffins. The amount can vary, but up to
3 equal parts by weight, 50: 50, based on the aromatic phosphate
4 are preferred, and 50:50 is most economical. A useul chlori-
nated parafin is available from ICI A~erica, Inc., under the
6 designation Creclor S-45.
8 Another preferred feature is the new composition
9 which also includes:
(ej a minor proportion of alumina trihydrate,
11 sufficient to enhance the flame re~ardant capability of
12 aromatic phospha~e component (b). The amount can vary widely
13 within these limits but preferably, the amount of alumina tri-
14 hydrate (which is a standard item of commerce), comprises
from about 5 to about 40 parts by weight per 100 parts by weight
; 16 of components (a) and (b) combined.
17
18 Still another preferred feature is the new composi-
l9 tion which also includes:
(f) a minor proportion of elemental red phosphorus,
21 sufficient to enhance the f'ame retardant capability of aromatic
22 phosphate component (b). Elemental red phosphorus can be used
23 in fairly broad ranges in amount but preferably, it will com-
24 prise from about 1 to abou~ 10 parts by weight per 100 parts by
weight of components (a), (b) and (c) combined.
26
27 The normally flammable polyphenylene ether resin (a)
28 is preferably of the type having the structural formula:
29
~ .. _ ._ __ .. _.__ _._.. ,.. ,. .. ~. _ . .. . ___~_
!, . , ~
~,E-45 ~ liO15798CH-:Z422
~ - r n
6 . Q
' 8 . ~ ~:
9 , :-,
wherein the oxygen ether atom of one unit is connected to the
11 benzene nucleus of the next adjoining unit, n is a positive
12 integer and is at least 50, and each ~ is a monovalent sub- ~ :~
13 stituent selected from the group consisting of hydrogen, halogen,
: 14 hydrocarbon radicals free of a tertiary alpha-carbon atom,
lS halohydrocarbon radicals having at least two carbon atoms be~ween
16 the halogen atom and the phenyl nueleus, hydrocarbonoxy radicals
17 and halohydrocarbonoxy radicals having at least two carbon atoms
i8 between the halogen atom and the phenyl nucleus.
19 . ','
A more preferred class of polyphenyLene ether resins : ;
21 for the compositions of this invention includes those o~ the
2~ above formula wherein each Q is alkyl, most preferablyj having
23 irom l to 4 carbon atoms. Illustrati~ely, members of this
24 class include poly(2,6-dimethyl-1,4-phenylene~ether; poly-
(2,6-diethyl-1,4-phenylene)ether; poly(2-methyl-6-ethyl-1,4-
26 phenylene)ether; poly(2-methyl-6-propyl-1,4-phenylene)ether; . .
27 poly(2,6-dipropyl-1,4-phenylene)ether; poly(2-ethyl-6-propyl-1,4- ~ :
28 phenyLene)ether; and the like.
29 .
.
- 6 - -
. . .
GE-459 ~ 8CH-2422
l Especially preferred is poly(2,6-dimethyl-1,4-
2 phenylene~ether, preferably, having an intrinsic viscosity
3 o about 0.45 deciliters per gr~m (dl./g.) as measured in
4 chloroform at 30C.
6 The choice of an aromatic phosphate plasticizer
can vary broadly.
The phosphate plasticizer is preferably a compound
o the formula:
~ 11 .
12 O
14 OR - P - O
16 oR2
17 . -
wherein Rl, R2 and R3 are the same or different and are aryl,
19 alkyl substituted aryl, or hydroxyalkyl. To keep the amount
of halogen low, it is preferred that no halogen be present
21 in component (b).
2~
23 Examples include cresyl diphenyl phosphate, tri-
24 cresyl phosphate, triiosopropylphenyl phosphate, triphenyl
phosphate, cresyl diphenyl phosphate, or mixtures thereof.
26 Especially preferred is triphenyl phosphate.
27
28 Commercially available aromatic phosphates which
29 have been found to be particularly useful are FMC Corporations's
Kronitex 50 and ~ronitex 300, which are isopropylated triphenyl
31 phosphate compounds.
- 7 -
GE-459 ¦¦
~ :,
1 The plasticizer (b) is added in amounts which will
2 be sufficient to provide a flexibilized composition within the ,i
3 meaning of the term described above. In general, the plasticizer
4 i9 present in amounts ran~ing from at least about 10 to 100, pre-
S ~erably from about 15 to about 65 parts by weight of plasticizer,
6 per 100 parts of resin component (a).
7 The present compositions also include thermoplastic :~
8 elastomers ~c), which are A-B-Al block copolymers. In general,
these resins comprise a polymerized center block B which is
derived from a conjugaced diene, e.g., butadiene, isoprene,
11 1,3-pentadiene, and the like, and polymerized terminal blocks
12 A and Al which are derived from vinyl aromatic, e.g., styrene ;
13 compounds, such as styrene, e~~methyl styrene, vinyl toluene,
14 vinyl xylene, vinyl naphthalene, and the like. Preferably,
the A-B-Al block copolymer will have terminal blocks A and Al
16 comprised of polystyrene and a center block comprised of poly-
17 butadiene.
18 -
19 The linear A-B-Al block copolymers are made by an -~
organometallic initiated polymerization process using, for
;~ 21 example, sodium or lithium metal or an organic derivative
22 thereof. The diene menomers can be polymerized with a mono-
23 functional or difunctional initiator, as is described in
24 Kennedy et al, Interscience Publishers, Vol. 23, Part II (1969),
- .!5~-.~9 .
'~ pages ~ Other methods of preparing these block copolymers
26 are described in Zelinski, U.S. 3,251,905 dated May 17,1966
27 and Holden et al, U.S. patent No. 3,231,635 dated
28 January 25, 1966. ~
~ 2g .
;
,, .. , . ,, ., "~, ", . ....... . .. . .
L57~ :
~E-459 1
1 Commercially available A-B-A block copolymers include
2 Kraton~ 411g, poly(styrene-butadiene-styrene) with 20% mineral oil
3 and the Kratons designated as K-1101 (polystyrene-polybutadiene-
1 4 polystyrene), K-1102 (polystyrene-polybutadiene-polystyrene), and
K-1107 (polystyrene-polyiso~rene-polystyrene), all from Shell
6 Chemical Company, Polymers Division. .
; 8 Hydrogenated A~B-A block copolymers can also be used
as thermoplastic elastomers in the present compositions. These
are prepared by techniques which are well known in the art. Seet ;;
11 for instance, the disclosure in Jones, U.S. 3,431,323, dated
12 March 4, 1969. A preferred commercially available copolymer
13 of this type is Shell Chemical's KG-6521 resin.
14 :-
I The thermo~lastic elastomer (c) ean vary broadly in
16 amount, but generally is present in amounts from about 10 to about
17 10~, more preferably from about 15 to about 65 parts by weight of
18 thermoplastic elastomer per 100 parts of polyphenylene ether (a).
19 :
Other ingredients, such as fillers, reinforcements,
21 pigments, stabili.zers, lubricants, and the like, m~y be added
22 for their conventional purposes.
23
24 The manner in which the present compositions are
prepared is not critical and conventional methods can be employed.
26 ¦ Preferably, however, each of the ingredients is added as part of
27 ¦ blend premix, and the latter is passed through an extruder, e.g , :
28 a 28 mm WP twin screw extruder, at a~ extrusion temperature of
29 from about 350 to about 550F., dependent on the needs of the
particular composition The strands emerging from the extruder
. ., ~ ,_
J-459 l
1 ~ may be cooled, chopped into Pellets, and molded or calendered to
2 any deslred shape.
4 Description of the Preferred Embodiments - The
_ .
following examples are illustrative of the compositions of this
invention. They are not intended to limit the invention in any
8 manner. -
9 EXAMPLES 1-10 . : -
1~ . ,, ~
11 The ollowing blends were prepared in a 28 mm Werner
12 Pfleiderer twin screw extruder and tested for physical properties
13 and flame retardancy by the Underwriters' Laboratory U.L. 94 test
14 and the GE Oxygen Index Test, with results set forth in Table 1:
16
7 ~ - ;-~
,~ 19 I . '. ~ :,
20 ~ :~
22 1 ~`~
24
26
28
2g ~ , ' .'
'. '''
'_ -10- ::
.,, .~
. _ . - ~
E-459 S 75~ :,
. ,
.~
O u~ 0 r~
~ ~ ~ `I o 1~ ~
~o
" ~ , .
J rl u~ O r~
u~ cr I lt- ~J I I I C'`l l O l ~ ~ "l
4 h ~ ~--1 ..
. ~
o u~ o r~ ~ ,~
.,J C~ 00 1 u~ ~ I I ~ I I O u~ ~.
6 u~to ,~ ,1
~: h .
o a~ .,
u~ O u~ ~ .,
7 ~ ~ t~ o~o ~
,~ o ,~
U~ o C~l
8 ~ 0 O O o o ll~ .14 .
-. 9 o ~ ~t I o I ~ o ~) h I "
t~ ,~
~0
, ~ ~ ~q O O O O O~ p~
h ~r)l ~ I ~ O ~ I I O u) rl I
11 J_l ¢~ ,-1 ~ ~ : .
12 a~ u~
., a~ I o o o o ,~ ~1 :
~¢ ~1 ~ o~ u~ I
13
14 o ~ o o o ~ c~l
.c ~ ~: .
,~ ta :
o~ o
P~ ~ o o o o r~ r~ ~.
1~ ~a o ~1 ~o I ~ ~ I II ol~ I ' -'~ '
a~ ~ c~ , :
17 N 1:4 .
r~ ~ O O O O O ~
18 ,n ~ ,~ o~o I -
rl r~ I~ ,~
X ~ ~ .,
19 ~ o .,1
o o o~ sl :.
¢ ¢ ~ I ~ I I I I O ~D ~ I . .
~ ,~
. Q) I b~
21 ,~ o ~
,~ ~ (U ~ ~ I a) ~1 ~ i ,. . .
22 ~ ,~, ~ 0 ~ ~ ,~ o ~ . ~
~ ~ ~ ~ o ~ ~ U~ ~ :: , .E-1 ~J h-rl ~ u~ O u rl rl
23 ,~:
bC ~ q 0 1 1 O ~
~1 G ~ OC) a) 1: ~. .
~ ~ r' '1 ~
24 3~ 1 a) o u~ D o a~~ ~J u ~ 0 .:
X O ~ :
~ ~ h 0 0 1--I aJ ~ ~ O ~ ]J ~O ~C r
.~ ,s:: a) ~ ~ 0 1~ JJJ-) ~1 ~ ,CL, I u~ ,c:~ O O ~I
~ Q p ~ a~ tn O O 1~
0 ~ ~ e~ elJ 51 ~ ~ ~ E~ - r-l r-l ~D
~: u ~ o o ~ a~ u~r~ X X r-l r l r~ C~
v S-I rl ~ ~ U U~:) r-lal~1 al I r~ O X S~ a, al ea
e~ ~ aJ ~ U~ ~ 0 .~~. 0 _ U C) U ^ U~ ~ ~ U U U C 1 ~
P I 1 0 ~-- (U Q~ U C)~ 0 0 ~ rl a ~ ~ ~-,1 rl r~ 0
~ 7 ~_~ ~ o u r~ O 1 0 ~ ~ a) ~ O E3 ^ ~; X ~ C E¦ U U U
t:~r-l rl rl C~l aJ tJ ~ J 0 0 h ~ ~rl e~ tq rl ~1 0 0 aJ e~ e~
OC~J ~,U J~ O O S~ ~ S~ O U ,1, a S~ S~ ,~ S~ SJ
2 8 rl ~ ~ td e~ O U ~ ~ e~ ~
u P 0 Z El s-l 0 U u U u u S-l u~ rl rl W rl ~1 O
aJ rl r~l (~ 0 0 0 U U) 0 la 0 U~ ~ ~ U u~ a u ~1 s~ u, u~ r-l r-l r-l r~
29 ~ cq o c s~ s~ ~ ~ h ~ O ~1 ~ U - - ~ r l r-l r-l
P~ O P~ d U D ~ .~: aJ a~ r-l X ~ ) C) al C~ C~
~ ~ ~ E~ O o~::X~
~ O ~ ~ ~ O ~) h 1~
~ r~ ~ 0 D U ~ a~ e~ b4
~ '
.
.
, ~ v'
_ .. ... . , .... ... _ _, _ . . _, . . _ , _ _ _ . ., . , . _ . _ _ . . . . _
~E-459 li
1 It is o~ particular interest to note that in the
2 above flexible blends which contain an aromatic phosphate as the
3 plas~icizer, good self-extinguishing properties are obtained.
4 Thus, the present compositions, particularly those containing
between 20 and 80 parts by weight of A-B-Al block copolymer
6 per 100 parts by weight of polyphenylene ether and aromatic
7 phosphate, are flame retardant without the chance to produce l~
8 toxic and corrosive halogen-derived products on incineration.
EXAMPLES 11 and 12 . ~ .
:
11 Following the procedure of Examples 1-10, the
12 listed compositions are prepared, having the properties set
'6 forth i able 2: ;
221 . ' .
22 . . :' .
24 .
~8 ~
29 .
. ~ ' ~ ,
__. __ ~ _ ..
q~
J~-459
1~
2 ~ c
4 ~ ~ . ~ ~
~ .~ .,
6 c~ ~ ~ ~
8 ~0 ~ `
¢ ~a h O ~ : -
~ u a) o~') o oo ~ ~ .1 p, ,
n u~ Op::l ~ I ~ ~ O ~ ~1 h ,1 .:
7 ~ ~1 0 .~
rC ~ C~ ~ ,
11 C) aJ u7
C ~ ,~ h
,. .~ ~ ~
L .~: ~ ~ ~ O .: :
~ b~C`J 00~') O O ~ C~
a~ o ~ ~ I O U~ O
13 ~ ~ c~ ~ co ~ ~ o ~
P~ ~d ~ ~
?~:~ , ~ C
14 'o' ~ ~
~:4 C ~ ~d o
C S~ ~ ~
1 6 tn E~ ~d I ~ ~ td
: ~ h ,~~1 0 o ~ o o ~ t~ .,~
~'17 ~ ~1 ~ ~ or~ ~t~
O O ,~ 1 td ,~
1~3 ~ ~) ~ o ~,1 .
~n .~: ~d u~ ~
19 ~o o ~ X ~ .
V :q ~
2 0 tn,l , ~n~;
O ¢ ~ a)o ~ ~
21 ~ ,~ t~ ~ tn~ O
O I ~ ~ 1 0
~ ¢ ~1 ~ n .
q ~ ~ I a) ~ ~1 ~ ~
., . ~ ~ ~ td ~ :~ d O aJ
. ~ O v ~ ~ ~ a) ,s~ v
" t~ a) ,~ td J~ ~ V p~ td
.) ~ I a) tn ~ 4J'~ td ~n ,~1
O ~ d I 4~~) ~ ,s; o ~4 tn J
~-1 ~ ~ q) td ,~ tU ~ X ~ C ~
24 D r~ S ~: S tD P h tn tD tD tD tn ~ tn tU
cd V U p. t~ cd ~, I tn ~ O - O ~
E~ tn (D tU tn o h C~ 4~ ~~ ~ S~ tU ,~ p ~rl
~ ~ O r~ ~ ^ ~ ~ r~ trJ ~ r~.~
~ ~r~ tU S~ U UL~ ~ ~ ~ tU t~ ~ tD V C) (D
I td ~ C P. tn tn ~ tu ,_1 cn tU X ~ o cd rl ~d P-
26 ¦ * ~ o " ,~ td ~ p (U ~ ~ V o tD~ W
I P ~ p~ ti ~ ~ O E3 ^ 'P cd 1~ S~ h
O ~ p V o o ,~ tn ,~ 0 tn ~1 ~ ta ~ tU ,~
2 7 ,~ --~ tu td El ~L ~ h tU (D ~ H tU O O E3 O
~ ~,s:: Ei h o IJ o rl ~1 td '~ ~E3 P ~ h tn ,~ ¢ rl
~U ,1 ~J ~ tU ~ tn ._ ~ ." ~ ~rl tu J- td
Q ,~tn O ~ S S ~ tn ~, ~ J bO ~ t~ cU H 5
C!~ O ~1, td ~ ~J tU C O ,~ ~ O ~ .C C 7 0
. ~ ~ Q ~ tU ,~ , t~ ~ t~ H ~
'ir~A tdE~ , ~ O E~ ~Ll ~ O
X O td ,L~ o ~ S I
W C) ~ td ,Q t~ ~ tD
.
~ .. .,---- . . ., ... , -- . .---- ~-- .
,E-459 ~ 5~ ~
l I~ is noteworthy that in these compositions, comple~e~
2 replacement of the aromatic phosphate by chlorinated paraffin
3 is catastrophic to the flame resistance, whereas up to 50% ,'
replacement is only slightly detrimental.
6 EXAMPLES 13 - 15
7 Follo~ing the procedure of Examples 1-10, the ,,
listed compositions are prepared, having the properties set . ,'
forth in Table 3: ,~
2 ,
, .''. '~
' 17 . . ' ~' ' .
1~ . ' ~'':' '
. . :'' '
21
~24 . ~ :
"
26 ~ :
28
29 .
/E - 4 5 9
~ ~ :
l :
3 .
4 tJ ~, N
S ~ n I o c~ ~7 o o ~ ,,5 '
E~ ~ OLn --~ p, ,. '
~ ~ 6 3 ~ .~ o
7 ~:
8 ~ ~ oo ~o or- ~o ~ .:
g ~ ~ ~1 ~ ~ ~ c~ o ~n ~ ~ ~ . .
~ ~ ,1 ~ ~ .
1~ ~ ~ rl ~ ,~
:,
12 ~ ~l oo ~o o~ ~ 'd o
--1 0 ~ I `D ~ ~ ~ O r l ~
3 h~ C~ o ::
14 ~ h ~ . .
t~ ~ : ',
ta
16 u~ ~1 ~ ' o; '~
17 u7 ¢ ~ ~ -
18 a) J ~ ~ ;~
'' 19 ~ a) ~ X
" . ~ o ~
t~ P~ ~ ~ .
td bO a~ o~
2 2 ~ ~ ,h ~ ~ . .
~ ~ ~ t~ o
~ O a
~d a~ ~1 ~ V ~ ~ r~
~ E-~ ~ I O U) ~ al ~rl 07 1
,~ ~1 ~ V ~ V V V Jl 0
;; . ~ p~ X ~ ~ ~
24 ~ ~ 5 ~ a) '~ o ~
.~ 0 JJ ~ .~ :~
v e _~ O rl o ,_ ,~ ~
~ ~ ~ v o~ - ~ v c) ,-
., ~ ~ ~ n O ~ 0 ~) X ~ ~d ~rl
P- ~ v ~ ~ ~ a) ~ e ~
~, ~D ~,.,, p,,~ ~, ~ ?~ o e ~ h .C ; : :
O c~ u o t) ~ ~ ~n ~ rl ~
27 . rl ~ O ?~ ~ v ,1 ~n O
v ~ e s~ ~ ~ e ~rl ,J ~ 5 h u~ r~
~ rl ~ O aJ,~ U~ U ~ v- ~1
28 ~ u~ o s~ u~ c . ,,
v ~ ~ ~ ~ ~ x~ c~
~ ~ ~i ~ ~ f~ O E~ ~3 3 0
~ ~ X o n~
~1 c~ ~ . rd~ U
- 15 -
- ... ,. - , . . ~ - .
G~--459 llV1579
,~
1 It is seen that the properties can be retained m
2 with significant cost advantages by addition of alumina
3 trihydrate. .:
4 EXAMPLES 16 - 17 ~ ;,
6 Following the procedure of Examples 1-10, the
7 listed compositions are prepared, having the properties set
8 forth in Table 4:
: 11 . .,
3 , :~
~, 16
8 .
. .
22
26
29 .
- 16 -
,E - 4 5 9 ~ S~3
~:"
2 I ~ .
3 ~ .
tl .
4 r~ Q~
c)Pl r~ .
~ r~) tn
7 ~ ~d ~ ¦
8 ~ ~ ~ trl ~t t~
9 ":Q' ~rl
~1 ~ . ~ . ~4
' ~ ~ ~a " .
~I h ~1 o o o ~ o ~ ~ ~,~
~3 ~1 '~ '~ ~ o c~ tn ~,
12 ~ o ~
13 o c~ ~u tn
.: :4 ~ .,1
14
~ o a ~
:-~ 15 ~ ta I oo o 0 ~ u~ u,
~IJ, ~ J I O O
.; ~ r~
~ ¢ '~
17 ~ , a)~ ~ ~
a~ ~ . -
18 o tn td u~
19 ,1 td ~ 4 X
o ~ a ,~ o
~ ~n ~ tn
o ,r~ ~d ~0 tl~ o o
21 c~ P~ u ~ tn ~ ~ .
~ .Q 0 ,a ~
2~ ~ ,c ~ ' ~ ~d u
~ ~,~ ^ o ~ ~ ~ d ..
"" ~1 ~ ~ U ~ ~,1 P~
, ~ ~ ~ I tU ~n h tn tn ,,1 ~n~
~a ~ ~ut~ u O ~ ~ ~ o .
. ~ ~ h tU td ~ tn .C X a ~
2l~ ~ ,~ ~ "~ tu tu p~ tn
tn ~ ,~ ~ u ~ tu .~ t~ ~
~ ~i ~ O ~rJ O rJ oo ,~ tn ~ d
h ~ p,tj h a~ ~u~ "~1 tJ
26 td I tu ~d ~ ~ tn ~C e
~_ ~ ,~ t~r~ ~ ta u a tu r,l ~ o ,u
: ~ t ru ~ tn O e
O r,~J ~ u O o ~tn ~,1 ta ,~ td
27 . .,~ ~~ tU ~ E O ~ a) ru r~ u ~ ,. O
~1 ~ E3 ~ 4 Ei~r~~ rd\~l ~U h tn
ru rJ r~ ~:L O ~U ,~ ~ r~ U r~ W E3 u-
28 ,~ o p~ ~a ~u '~ ~ ~ o ,~ u o ~:
n ~tu,~ .
,. ,. ta F: ~ ,~ o E~
7 X O td .J~
~ ~ ~ . td ,~
- 17 -
_ _.,. ... ~ . _
~ S ~ 8CH-242~
It is seen that red phosphorus permits the
incorporation of high amounts of rubber, while maintaining
good flame retardant characteristics. These compositions
also have the desirable feature of being free of halogen.
Obviously, other modifications and variations
of the present invention are possible in the light of the
above description. It is, therefore, to be understood that
changes may be made in the particular embodiments disclosed
herein which are within the full intended scope of the invention
as defined in the appended claims.
The instant application discloses, but does not
claim, subject matter disclosed and claimed in the related,
commonly assigned Canadian Application Serial No. 291,790,
filed November 25, 19770 ~-
- 18 -
.
