CA1062387A - Flame retardant polycarbonate composition - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A flame retardant polycarbonate composition comprising in admixture an aromatic carbonate polymer and an additive which may be the metal salts of either monomeric or polymeric aromatic sulfonesulfonic acids, or mixtures thereof. The compositions are additionally non-opaque when both the aromatic carbonate polymer and additive have a refractive index in the range of 1.54 to 1.65.

Description

~o6z3s7 This invention is directed to a flame retardant polycarbonate composition and in particular an aromatic polycarbonate containing in admixture therewith a particular flame retardant additive which may be the metal salts of either monomeric or polymeric aromatic sulfonesulfonates, or mixtures of these.
; Background of the Invention With the increasing concern for safety, there is a positive move towards providing safe materials for public and household use. One particular area of need is that of providing flame resistant or flame retardant products for use by the ultimate consumer. As a result of this demand, many products are being required to meet certain flame retardant - criteria both by local and federal government and the ~ 15 manufacturers of such products. One particular set of ; conditions employed as a measuring standard for flame retardancy is set forth in Underwriters' Laboratories, Inc.
. , Bulletin 94. This Bulletin sets forth certain conditions by which materials are rated for self-extinguishing characteristics.
In the art, there are many known flame retardant additives which are employed by mixing with products to render such materials self-extinguishing or flame retardant.
q Such flame retardant additives have been known to be i~ .
employed in amounts of 5 to 20 weight percent in order to be ` effective in extinguishing burning of those products which are combustible. It has also been found that such amounts can have a degrading effect upon the base product to be rendered flame retardant, resulting in the losses of ~, 30 valuable physical properties of the base product. This is .

,, - .
., particularly so when employing known flame retardant additives with the base product polycarbonate resins. Many of these known additives have a degrading effect upon the polymer.
Description of the Invention It has now been surprisingly discovered that an ~--aromatic polycarbonate can be made flame retardant by incorporating with the aromatic polycarbonate minor amounts of certain additives, which additives are inert and do not degrade the aromatic polycarbonate. The particular additive - employed herein is unique in that even very minor amounts render the aromatic polycarbonate flame retardant. The amount of the additive employed herein can vary, preferably, from 0.01 to about 10 weight percent based on the weight of the aromatic polycarbonate.
` More specifically, the particular additive of this invention is the metal salt of either the monomeric or :~ .
- polymeric aromatic sulfonesulfonates or mixtures of these.
The metal salt employed in the practice of this invention is --either the alkali metal or alkali earth metal salt or mixtures of metal salts. The metals of these groups are sodium, lithium, potassium, rubidium, cesium, beryllium, ~ magnesium, calcium, strontium and barium.
A The aromatic sulfonesulfonates employed in the i 25 practice of this invention is a substituted or unsubstituted ;
-~ aromatic sulfonesulfonate wherein the substituent consists of an electron withdrawing radical. As employed herein and ~ within the scope of this invention, any of the -! electron withdrawing radicals can be employed in the .

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~, , , , ~ . ' .
', ,' - :"~ ~ -' ' -, ... ~. , practice of this invention. However, preferably, the electron withdrawing radical or substituent employed in the practice of this invention is the halo-, nitro-, trihalomethyl and cyano electron withdrawing radicals or mixtures of these electron withdrawing radicals.
The electron withdrawing phenomenon, or as it is also referred to as electronegativity, is defined in Basic Principles of Organic Chemistry by Roberts and Caserio, 1964 (pages 185-186), and Physical Organic Chemistry by Jack Hine, McGraw-Hill Book Company, Inc. 1962 (pages 5, - 32 and 85-93). Briefly, the electron withdrawing phenomenon is where the radical has a strong affinity for a negative charge, namely electrons, but still remains covalent and does not form an ion. This is an extremely brief description of this phenomenon and is merely set forth here to describe the electron withdrawing effect. Reference should be made to the texts set forth above.
In the practice of this invention, the types of aromatic sulfonesulfonates employed herein may be either the monomeric form or the polymeric form or mixtures of these.
When first considering the monomeric form, the metal salt of the monomeric aromatic sulfonesulfonate can best be represented by the following formula:
R'(SO2)1_2R (SO3M)l_6xo-ll I.

wherein X is an electron withdrawing radical, M is a metal which may be selected from the periodic table of either an --alkali metal or an alkali earth metal, and R' and R'' may ~' be either an aryl radical of 1-2 aromatic rings or an aliphatic radical of 1-6 carbon atoms and they may be the ,, ~

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: ' .
, ' . ' . , ~: ~ :
.

same or different.
. .
It is to be understood, however, that R and R together must contain at least one aromatic ring.
When the polymeric form of the aromatic sulfonesulfonate is employed in the practice of this invention, the polymer consists of at least 2 repeating units in the following formula:

! ~ ~AB~m[CB]n ~ II.
:' P . ' .

In the above formula, B is an aromatic sulfone having the following formula . O

and A and C are dioxy radicals having 1-2 aromatic rings and may be independently selected from ' (S03M)y o -~ o-:, -~ lS or -O--~ O

.~ ' .
:
. 4 ., . ,, .. , . . .

-, . .
. ~ ~ ,' -~06Z387 8CH-1947 or (S03M)y O ~J~ R ~0 x0-4 In the above formulae, M is a metal which may be either an alkali metal or an alkali earth metal, R is an alkylene or alkylidene radical of 1-10 carbon atoms and y is an integer of from 0-4 providing that the sum of y when employed in Formula II is at least 1. In the above formulae, X is a halo electron withdrawing radical~ As shown, the polymeric form of the `~ additive may or may not have an electron withdrawing radical and if it is employed, the electron withdrawing radical is only a halo radical. Also, in Formula II, m is l and n is an integer of from 0-20 and p is an integer from 2-200.
Also, in the practice of this invention, the above units of LAB~ and ~CB~ can be randomly selected while the polymer structure can be either a copolymer, a random copolymer, a block copolymer or a random-block copolymer or mixtures of ~ these polymeric forms. In addition, the ratio of sulfonated ;~ aromatic rings to unsulfonated aromatic rings can vary from . greater ~han l to 1 to as low as that which is necessary to render the polyca~bonate flame retardant and this may be 1:100.
In the practice of this invention, there are many polymers that meet the requirements of Formula II above and which offer excellent flame retardant characteristics to an aromatic polycarbonate. The preferred polymeric additive employed in the practice of this invention has the following formula:
;~
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~ _ 5 _ .'~

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o=u~=o ..
.~ o o~n~_o .

o ~ .
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. o~q=o ~:'..

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Another preferred polymeric additive employed in the practice of this invention is one containing an electron withdrawing radical and has the following formula:

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,, :, ., .. , ., - ' . ' Preferred Embodiment of the Invention In order to more fully and clearly illustrate the present invention, the following specific examples are presented. It is intended that the examples be considered as illustrative rather than limiting the invention disclosed and claimed herei~. In the examples, all parts and percentages are on a weight basis unless otherwise specified.
- Example I
Ninety-nine (99) parts of an aromatic polycarbonate, prepared by reacting 2,2-bis(4-hydroxyphenyl)propane and phosgene in the presence of an acid acceptor and a molecular weight regulator and having an intrinsic viscosity of 0.57 is mixed with 1 part of a finely ground dehydrated additive listed in Table I by tumbling the ingredients together in a -15 laboratory tumbler. The resulting mixture is then fed to an -:
extruder, which extruder is operated at about 265C., and the extrudate is comminuted into pellets.
The pellets are then injection molded at about 315C. into test bars of about 5 in. by 1/2 in. by about 1/16-1/8 in. thick. The test bars (5 for each additive listed in the Table) are subject to the test procedure set forth in Underwriters' Laboratories, Inc. Bulletin UL-94, Burning Test for Classifying Materials. In accordance with this test procedure, materials so investigated are rated either SE-0, SE-I or SE-II based on the results of i 5 specimens. The criteria for each SE rating per UL-94 ,' . .
.

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. . .

is briefly as follows:
"SE-O": Average flaming and/or glowing after removal of the igniting flame shall not exceed 5 seconds and none of the specimens shall drip flaming particles which ignite absorbent cotton.
"SE-I": Average flaming and/or glowing after removal of the igniting flame shall not exceed 25 seconds and the glowing does not travel vertically for more than 1/8" of the specimen after flaming ceases and glowing is incapable ; of igniting absorbent cotton.
- "SE-II": Average flaming and/or glowing after removal of the igniting flame shall not exceed 25 seconds and the specimens drip flaming particles which ignite absorbent cotton.
In addition, a test bar which continues to burn for more than 25 seconds after removal of the igniting flame is classified, not by UL-94, but by the standards of the instant invention, as "burns". Further, UL-94 requires that all test bars in each test group must meet the SE type rating to achieve the particular classification. Otherwise, the 5 - bars receive the rating of the worst single bar. For example, if one bar is classified as SE-II and the other four (4) are classified as SE-0, then the rating for all 5 bars is SE-II.
The results of the different additives within the .
.
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scope of the instant invention are as follows with a control being the aromatic polycarbonate as prepared above without the additive of the type set forth herein.

Table 1 /

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~06;~387 8-C~I-1947 O O O HO O
U~
a a~

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n Q Q QQ n U~
.Y
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:
~ ~ H H HHHH HH HH H O
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:

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~- O E~
S~ ~D ~ X 0~ OCO O
.. o ~ +
., Z ~ ~ ~ _I O O _IO _I O
.:
..

.,, _ ,., O

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s s o-,~
. I Q) O S~
~, ~ a~ o o ~ o

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... a~ E; ~ OO ~
_~ o ~r ~o o ~qs t) u~ ~ ~1 In ~,o ~ O O O
. j; . ~ ~ -~1 0 ~S Lq :~ ~ I ~ --I O t~ _1 S
s a~ t~ S q~I ~ Q
., ~ S ' U ~~ 1~
a n~ ~ ~ S
~ o ~'~ ~ o ~o ~ o ~ q~ o o E~ qr ~ ~O I ~ ~ o ~
~ O' 'OO ~ a ~ u ~ I ~ o ~1 3 ~> ~ o ~ ~q~1 o ~ ~ s ,~ ~ 3 o ~ o ~,1 ~ m ~ o ~a _l ~ O~ a) r .1 ~rl I ~ (d O ~ O ~O q~ O S
O :~ O ~ C o u~ 6q a ~ a bq a ~
i, .
... . .
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:
.............

~ 1~
Z ~ ~C I O

~ O [~) ¦ O O ~ I ~ [ ~}
~ ~ o ~ o o l OE~ o ~ _1 ~ o ~ ':

o_ ~ _o ~ o= ~~ :o '," 0~ ~D ~ ~ ~ [~ ~ ~1 .,. ~o o~ ~ o:ll=o ~q ~ ~ [~ [~ :
~ ~-y~o ~ ~ :~ ~ ~
:; 5 ~ ~ ~ ~
... ~ ~x ~ ~l~
~ . I ~ [~ ~-x o [~ ~o (~1 .~ ..
o ~ I ~ ~ ~ o=u~= o ~ o=~q .o " -~q o = cn: o ~a -l ~o ~
p .~ ~ ~q~n ~ ~/

~ u~ J ~ ~ ~q _ ~ ~o ~I~ ,. ..
. ~ o a~ ~ ~ ~ T
.. , ~ o , .,,~ ~ o . ~ o a ~ ~ ~ ~ ~ .

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Example II

This Example is set forth to demonstrate the effect of the flame retardant additives of this invention at the lower limits of 0.01 weight percent based on the weight of the polymer composition.
In preparing the test bars for this Example, 99.99 parts of the polycarbonate of Example I is mixed with 0.01 weight percent of the additives listed in Table 2 emloying the same procedure. Test bars are then molded using the same procedure employed in Example I. The test ~ 10 bars are subjected to the same test procedure of Example I
; with the following results:

~ TABLE 2 .

/
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,~

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106Z387 8 -CH' 19 4 7 '~
, ~ o=cn ~ ,, ~: H H H (~
'. ~ ~ O
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q ~
'''' O'E~
~D ~ O
~ o -a~ ~ ~ . ~
.. Z ~ ~ r O ~,, .
~ ~ . ~ .

o=~n=o j~ ~
0 0~ ', ', r 1 S

~o ~ O u ~ ~,S (~ Gl- O

-,~
~ O ~ O
1~ ~ Q u~

.~ .
~ ~5 .", ~ ' ,.

i':, ' '-':' : ' ` ' ' . '' ` :. ` : :. -.' ' ~.. ' . . - : ' ` ~ ' . ,. . . -106238'7 Example III

This Example is set forth to show the effect of a known commercially available flame retardant additive.

A.

Example I is repeated except that in place of the additives employed therein, only 1 part 1,2,5,6,9,10-hexabromocyclododecane is used herein. The results obtained upon evaluating five (5) test bars are the same as obtained for the Control shown in Table 1 above.
'' B.
.,~
Part A. above is repeated but using 5 weight percent of the above additive, namely 1,2,5,6,9,10-hexabromocyclodo-decane. The results obtained are the same as obtained in Part A. above.

: C
~ 15 .y ~^ Part A. above is repeated but using 10 weight percent of the above additive, namely 1,2,5,6,9,10-hexabromocyclododecane. At this level of additive, test bars ~ are rated SE-I~. However, the polycarbonate is badly :~ 20 degraded as evidenced by severe dark streaking of the molded test bars, which degradation does not occur with the additives of the instant invention.
3 Example IV
Example III is repeated except that hexabromo-biphenyl is employed herein. The results obtained are ~ .

:.

:~ . . . . . ......... . . . . . . . . .

` 1062387 8-CH-1947 essentially the same as those of Example III.
Example V
Example III is repeated except that the additive employed herein is a combination of antimony oxide and a material which is a mixture of polychlorinated biphenyl (Aroclor by Monsanto Company). The proportion of the ingredients of the additive employed in this example is based on 3 parts of chlorine per 1 part of antimony. The results obtained at 1 weight percent and 5 weight percent amounts are the same as in Example III.
However, at the higher amount, namely 10 weight percent, flame retardancy effect is noted, but with, again, severe degradation of the polycarbonate, as evidenced by the substantial reduction in the intrinsic viscosity of the molded test bars. As molded, the intrinsic viscosity of the test bars with 1 weight percent of the above additive is about O.S0. The intrinsic viscosity of the molded test bars containing 10 weight percent of the flame retardant additive of this Example is 0.253. This shows the severe degradation of the polycarbonate when employing this type of well known ; flame retardant.
In the practice of this invention, aromatic : `
- carbonate polymers are rendered flame retardant by the addition of certain particular additives which are the metal salts of substituted and unsubstituted monomeric or polymeric aromatic sulfonesulfonates and include mixtures of these.
The amount of the additives employed in the practice of this ~ invention may vary from 0.01 to up to that amount which .~ .
~ ~' ''';~

... . . . . . .
,. . . . .. , . ~ , . . ... .
... . . . . . . .

after further increasing of such an amount does not materially increase the flame retardant properties of the carbonate polymer. This is generally up to about 10 weight percent based on the weight of the aromatic carbonate polymer but may be higher. The amount of the additive to be employed can also be a function of the degree of flame retardancy desired.
It is not exactly understood how the additive of this invention functions or how such minor amounts can act as an effective flame retardant for the aromatic carbonate polymer. Analysis of the composition of this invention after being subjected to a fire temperature of about 600C. showed an unusually high percentage of remaining char. This leads one to hvpothesize that the additive may act as a cross-~ -15 linking agent when the aromatic carbonate polymer is ; subjected to fire temperatures. However, it is emphasized that this is only theory and should not be construed as actually occurring.
As indicated previously, the additive of the instant invention comprises the alkali or alkali earth metal ` salts of the monomeric or polymeric aromatic sulfonesulfonates - and mixtures of these. While a great number of such salts are set forth in the tables of the Examples of the instant invention, these are only a representative sample of the ; 25 additives of this invention. The sodium, calcium, magnesium, potassium, strontium, lithium, barium, rubidium and cesium salts of other aromatic sulfonesulfonic acids can be employed in place of those of the Examples with the same effectiye flame retardancy being achieved. These other ~et41 8alts of aro~atic sulfonesulfonic aoids are ;

- :- . - :

diphenylsulfone-4,4'-disulfonic acid, disodium salt methylphenylsulfone-4-sulfonic acid, calcium salt 2,3,4,5,6-pentachlorodiphenylsulfone-4-sulfonic acid, sodium salt 2,7-dichlorodibenzothiophene-S-dioxide-4,5-disulfonic acid, dipotassium salt 1,8-dibromodibenzothioxin-S-dioxide-2,7-disulfonic acid, disodium salt In the practice of this invention, the additive is generally prepared by well known methods in the art. For example, one such well known method involves taking an aromatic sulfone such as diphenylsulfone and subjecting it to sulfonation using either sulfuric acid, chlorosulfonic acid, fuming sulfonic acid or sulfur trioxide. These reactions can be carried out at room temperature or at elevated temperatures such as about 50C. The salt is then prepared by adding the proper alkaline reagent in sufficient amount to make the neutral salt. The salt is then recovered by precipitation ` or by distillation of the solvent.
In the case of a halo-electron withdrawing substituent, such as trifluoromethyl electron withdrawing substituent, it is best to start with the prepared ; 20 trifluorometh~l ~xomatic sulfone and then sulfonate as above, as well as preparing the salt thereof.
In the practice of this invention, any of the aromatic polycarbonates can be employed herein. However, particularly useful axe the aromatic polycarbonates prepared by xeacting a dihydric phenol, such as bisphenol-A
(2,2'bis(4 hydroxyphenyl)propane) with a carbonate precursor.
Typical of some of the dihydric phenols that may be employed '9 '~
. t ,' ' ' : -- 19 --' . ' '. ~ -.
- , . ~ .,, :
' , ' :.
' ' ' ' ' ' ~ ' ' ' : - '' in the practice of this invention are bis(4-hydroxyphenyl) methane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 4,4-bis(4-hydroxyphenyl) heptane, 2~2-(3~5~3~5~-tetrachloro-4~4~-dihydroxydiphenyl) propane, 2,2-(3,5,3',5'-tetrabromo-4,4'-dihydroxydiphenyl) propane, (3,3'-dichloro-4,4'-dihydroxydiphenyl)methane.
Other dihydric phenols of the bisphenol type are also available and are disclosed in U.S. patents 2,999,835, 3,028,365 and 3,334,154.
In addition, the reaction is carried out with the carbonate precursor in the presence of a molecular weight regulator, an acid acceptor and a catalyst. The preferred carbonate precursor generally employed in preparing carbonate polymers is carbonyl chloride. However, other carbonate precursors may be employed and this includes other carbonyl halides, carbonate esters or haloformates.
The acid acceptors, molecular weight regulators and catalysts employed in the process of preparing polycarbonates are well known in the art and may be any of those commonly used to prepare polycarbonates.
As stated previously, mixtures can be employed in the practice of this invention and are included within the scope herein. Mixtures consist of mixtures of the various metal salts of monomeric and polymeric aromatic sulfonesulfonates. The mixtures offer certain advantages such as SE-0 rating for 5 test bars and essentially no drips per test bar.

e , .' , , .
, , -It will thus be seen that the objects set forth above among those made apparent from the preceding description are efficiently attained and since certain changes may be made in carrying out the above process and in the composition set forth without departing from the scope of this invention, it is intended that all matters contained in the above description shall be interpreted as illustrative and not in a limiting sense.

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SUPPLEMENTARY DISCLOSURE
In the principal disclosure of my invention there are described novel flame retardant compositions comprising' aromatic carbonate polymers in admixture with fro~ about 0.01 to about 10 parts by weight per hundred parts of the polymer of an additive comprising given metal salts of a sulfonic acid of a defined class.
It has further been found that such additive may be effective for the above stated purpose when present in a concentration of as little as 0.001 parts per hundred parts of the polymer.
It has still further been found that when the additive as defined earlier has a refractive index in the same range as that of the aromatic carbonate polymer ie.
- lS about 1.54 to 1.65, the aforesaid compositions wherein the additive is present in about 0.001 to about 2 parts per hundred parts of aromatic carbonate polymer are not only flame retardant but are also non-opaque.
By non-opaque is meant that the polycarbonate compositions and shaped articles produced therefrom which may be in the form of sheet, for example, or merely in the form of pellets suitable for extrusion, are able to transmit light. The compositions may vary from translucent to ~,! transparent, depending upon the closeness of the refractive index of the additive to that of the aromatic carbonate polymer.
If the additive at the concentration employed is partially or totally soluble in the carbonate polymer, the transparency of composition and article will naturally be increased.
The refractive indices of the materials herein described are determined by the immersion method as shown in Physical Methods of Organic Chemistry (Weissberger -Interscience Publishers, Vol. II, 1960, p 1433).

.~ .

:- .
.. . .

A preferred additives for the formulation of non-opaque products which confer excellent flame retardency are identical to those previously defined upon pages 6 and 8.
m e non-opaque flame retardent compositions which comprise this additional aspect of my invention may further comprise other additives which are commonly employed in the formulation of non-opaque aromatic carbonate polymer - products, for example pigments, dyes, antioxidants, stabilizers, U. V, light absorbers, mold relea~e agents etc.
In order to illustrate the present invention more fully and clearly, both in its general aspect in providing flame retardent compositions and also in the ; more specific and newly disclosed aspect in providing non- ~ -opaque flame retardent compositions, the following additional examples are presented. All parts and percentages are expressed upon a weight basis unless otherwise specified. The examples are not to be considered as limiting the scope of the invention, this being elsewhere defined.
; Exam~le VI
; One hundred parts of the aromatic polycarbonates as in example 1 is mixed with 0.1 part of a finely ground ~i dehydrated additive as listed in Table 3. Test bar~ prepared as in example 1 are subjected to the UL 94 Burning Test, ~ with the bars oriented in the vertical position. The results -~ are classified into 3 grades, V-0 - V-II, the criteria for the grades being essentially the same as for those earlier given for the corresponding SE grades.
~ 30 The test squares are tested for light transmission in ¦ a Gardner XL 10-CDM instrument. The data shows the amount of ~ - 23 -.'~ .

, ' ',' - ' :
, incident light transmitted by the test sauares using air as 100~ transmission.
The result of an additive within the scope of the instant invention is as follows with a control being t'ne aromatic polycarbonate as prepared above wi~hout the additive of the type set f~rth herein.

~ - 24 -., .

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a~
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~, o J~ U 0 U kEl 0 0 .~ _ ~ J U r~ U ~ e ;~ n~ F ~ rl -1 rl e ,1 !. ~ 0 U 3 U 0 ~ 0 1 ~3 ~ '1 .-~i P ~ O O 111 0 ~1 111 ~
o e ~ 0 ~ 0, o ~ ~ O ~ O
~ ~ ~ Q~ 0 ~ 0 ~ ~
~ ~ ~ O ~ ~ ~-1 0~ 0 .~ ¢ o ~q 0 P. In _ 25-.
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" -- 8CH-1947 EXAMPLE VII
This Example is set forth to demonstrate the effect of the additives of this invention at limits of 0.20 parts per hundred parts of the polycarbonate.
In preparing the test specimens for this Example, 100.00 parts of the polycarbonate of Example I is mixed with 0.20 parts of the additives listed in ~able 4 employing the same procedure. Test specimens are then molded u~ing the same procedure employed in Example I. The test specimens are subjected to the same test procedure of Example VI with the following results:
Table 4 ... ~ .

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on ~ o - a~- I
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R

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P.
a~

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~ ~ æ
P ~ ~ ~ ~ 0~
, o ~ ~ u ~a ~ ~ u ~ o~ ~
o ~ ~ ~ u ~ ~ In ul u ~ o In, ~ O
O ~ ~0 In o ~ ~ ~ E.~ 1 CO , q~ al ~
~ 8 3 ~ i 3'-~1 o ~

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' ' . ,: `: ` '.
'` . ' . . ,~ ': ' :'' ' ' EXAMPLE VIII
This example is set forth to demonstrate the effect of the additives of this invention at limits of 0.30 parts per hundred parts of the polycarbonate.
In preparing the test specimens for this Example, 100.00 parts of the polycarbonate of Example I is mixed with 0.30 parts of the additives listed in Table 5 employing the same procedure. Test specimens are then molded using the same procedure employed in Example I. The test specimens are subjected to the same test procedure of Example VI with the following results:

. ~ ' ' .

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.. . . ;

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' :

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., , ~. . . : .
.

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P~ ~ ~ :~
U~
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o ~U ,o ..

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EXAMPLE IX
Thi~ example is set forth to demonstrate the effect of the additives of this invention at limits of 0.50 part.~ per hundred parts of the polycarbonate.
In preparing the test specimens for this Example, 100.00 parts of the polycarbonate of Example I is mixed with 0.50 parts of the additives listed in Table 6 employing the same procedure. Test specimens are then molded using the same procedure employed in Example I. The test specimens are subjected to the same test procedure of Example VI with the following results:

Table 6 .''' .

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. ~ ~
, - ' ' - ' In the practice of this invention, aromatic carbonate polymers are rendered flame retardant by the addition of certain particular additives which are the metal salts of ~ubstituted and unsubstituted monomeric or polymeric aromatic sulfone-sulfonates and include mixtures of these. m e amount of the additives employed in the practice of this invention will preferably be in the range from 0.001 to up to about 10 parts per hundred parts of aromatic carbonate polymer.
As indicated previously, the additive of the additional aspect of the instant invention comprises the alkali or alkaline earth metal salts of the monomeric or polymeric aromatic sulfonesulfonates and mixtures of the~e having a^refractive index in the range of 1.54 to 1.65. While a great number of such salts are set forth in the tables of the Examples of the ; instant invention, these are only a representative sample of the additives of this invention. The sodium, calcium, magnesium, potassium, strontium, lithium, barium, rubidium and cesium salt~ of other aromatic sulfonesulfonic acidscan be employed in place of those of the Examples with the same effective flame retardancy being achieved. These other metal salts of aromatic sulfonesulfonic acids are diphenylsulfone-4,4'-disulfonic acid, di~odium salt ; methylphenyl~ulfone-4-sulfonic acid, calcium ~alt 2,3,4,5,6-pentachlorodiphenylsulfone-4-sulfonic acid, sodium salt 2,7-dichlorodibenzothiophene-S-dioxide-4,5-disulfonic, acid, dipota~sium salt ; 1,8-dibromodibenzothioxin-S-dioxide-2,7-disulfonic ;~ acid, di~odium salt In the practice of thi~ invention, any of the aromatic polycarbonates can be employed herein these generally having a refractive index in the range of 1.54 to 1.65. These ~;
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are homopolymers and copolymers and mixtures thereof that are prepared by reacting a dihydric phenol with a carbonate precursor.
It is, of course, possible to employ two or more dif-ferent dihydric phenols or a copolymer of a dihydric phenol with a glycol or with hydroxy or acid terminated polyester, or with a dibasic acid in the event a carbonate copolymer or interpolymer rather than a homopolymer is desired for use in the preparation of the aromatic carbonate polymers of this invention. Also, employed in the practice of thi~ invention may be blends of any of the above material~ to provide the aromatic carbonate polymer.
The carbonate precursor may be either a carbonyl halide, a carbonate ester or a haloformate. m e carbonyl halides which can be employed herein are carbonyl bromide, carbonyl chloride and mixtures thereof. Typical of the carbonate esters which may be employed herein are diphenyl carbonate, di-(halophenyl) carbonates such as di-(chlorophenyl) carbonate, di-~bromophenyl) carbonate, di-(trichlorophenyl) carbonate, di-(tribromophenyl) carbonate, etc., di-(alkylphenyl) carbonate such as di(tolyl) carbonate, etc., di-(naphthyl) carbonate, di-(chloronaphthyl) carbonate, phenyl tolyl carbonate, chlorophenyl chloronaphthyl carbonate, etc., or mixtures thereof.
The haloformates suitable for use herein include bis-haloformates of dihydric phenols (bischloroformates of hydroquinone, etc.) or glycols (bishaloformatos of ethylene glycol, neopentyl glycol, polyethylene glycol, etc.). While other carbonate precursors will occur to those skilled in the art, carbonyl chloride also ; known as phosgene is preferred.
Also included are the polymeric derivatives of a dihydric phenol, a dicarboxylic acid and carbonic acid.
Tho aromatic carbonate polymers of this invention may be prepared by employing a molecular weight regulator, an acid .
, acceptor and a catalyst. The molecular weight regulators which can be employed in carrying out the proceqs of this invention include monohydric phenols such as phenol, chroman-I, para-tertiary-butylphenol, papabromophenol, primary and secondary amines, etc. Preferably, phenol is employed as the molecular weight regulator.
A ~uitable acid acceptor may be either an organic or an inorganic acid acceptor. A suitable organic acid acceptor i9 a tertiary amine and includes guch materials as pyridine, triethylamine, dimethylaniline, tributylamine, etc. The inorganic acid acceptor may be one which can be either a hydroxide, a carbonate, a bicarbonate, or a phosphate of an alkali or alkaline earth metal.
m e catalysts which are employed herein can be any of the suitable catalysts that aid the polymerization of bisphenol-A
with phosgene. Suitable catalysts include tertiary amines such as for example, triethylamine, tripropylamine, N,N-dimethyl-aniline, quaternary ammonium compounds such as for example tetraethylammonium bromide, cetyl triethyl ammonium bromide, te-tra-n-heptylammonium iodide, tetra-n-propylammonium bromide, tetramethylammonium chloride, tetramethyl ammonium hydroxide, tetra-n-butylammonium iodide, benzyltrimethylammonium chloride - and quaternary phosphonium compounds such as for example, n-butyltriphenyl phosphonium bromide and methyltriphenyl phosphonium ; bromide.
Also, included herein are branched polycarbonates wherein a polyfunctional aromatic compound i5 reacted with the dihydric phenol and carbonate precursor to provide a thermo-plastic randomly branched polycarbonate~
Theso polyfunctional aromatic compounds contain at least three functional group~ which are carboxyl, carboxylic anhydride, haloformyl or mixtures thereof. Examples of these A

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polyfunctional aromatic compounds which may be employed in the - practice of this invention include: trimellitic anhydride, trimellitic acid, trimellityl trichloride, 4-chloroformyl phthalic anhydride, pyromellitic acid, pyromellitic dianhydride, mellitic acid, mellitic anhydride, trimesic acid, benzophenone-tetracarboxylic acid, benzophenonetetracarboxylic anhydride and the like. The preferred polyfunctional aromatic compounds are trimellitic anhydride or trimellitic acid, or their haloformyl derivative~.
Also, include herein are blends of a linear polycarbo-nate and a branched polycarbonate.
As indicated previously, the additive employed herein can consist of mixtures of the metal salts. These mixtures can be mixtures of the various metal salts of the monomeric substituted aromatic sulfonic acids or mixtures of the variou~
metal salts of the polymeric substituted aromatic ~ulfonic ! acids, or mixtures of the metal salts of the monomeric and polymeric sub~tituted aromatic sulfonic acids. The mixtures have proven certain advantages such a~ V-0 rating of 5 test bars and e~entially zero number of drips per bar.
It will thus be seen that the objects set forth above among those made apparent from the preceding description are efficiently attained and since certain changes may be made in carrying out the above process and in the composition set forth without departing from the scope of this invention, it i~ intended that all matters contained in the above description shall be 1nt-rpr-t d a~ iLlu~trativ- and not in li~iting ~-n~-.

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Claims (17)

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. A flame retardant aromatic carbonate polymer composition comprising in admixture an aromatic carbonate polymer and a minor flame retardant amount of an additive selected from the group consisting of the monomeric and polymeric alkali metal and alkaline earth metal aromatic sulfonesulfonates, and mixtures of these.

2. The composition of claim 1 wherein the composition comprises in admixture 0.01 to about 10 weight percent of the additive based on the weight of the aromatic carbonate polymer composition.

3. The composition of claim 1 wherein the monomeric metal aromatic sulfonesulfonates have the following formula:
R'(SO2)1-2R"(SO3M)l-6X0-11 wherein M is a metal selected from the group consisting of alkali metal and alkaline earth metal, R' and R"
are independently selected from the group consisting of aryl radicals of 1-2 aromatic rings and an aliphatic radical of 1-6 carbon atoms, provided, however, that R' and R" together must contain at least one aromatic ring to which the SO3M group is attached and wherein X is an electron withdrawing radical.

4. The composition of claim 3 wherein the electron withdrawing radical is selected from the group consisting of halo-, nitro-, trihalomethyl- and cyano-radicals and mixtures thereof.

5. The composition of claim 3 wherein the electron withdrawing radical is chlorine.

6. The composition of claim 3 wherein the additive is disodium 4,2',4',5'-tetrachlorodiphenylsulfone-3,5-disulfonate.

7. The composition of claim 3 wherein the additive has the formula:
.

8. The composition of claim 3 wherein the additive is disodium diphenylsulfone-3,3'-disulfonate.

9. The composition of claim 1 wherein the polymeric metal aromatic sulfonesulfonates consist of at least 2 repeating units of the following formula wherein B is an aromatic sulfone of the following formula and A and C are dioxy radicals having 1-2 aromatic rings and are independently selected from the group consisting of and wherein M is a metal selected from the group consisting of alkali metal and alkaline earth metal, R is an aliphatic radical selected from the group consisting of alkylene and alkylidene radicals of 1-10 carbon atoms, X is a halo electron withdrawing radical, y is an integer of 1-4, m is 1, n is an integer of 0-20 and p is an integer from 2-200.
10. The composition of claim 1 wherein the additive has the formula:

Claim 10 continued

11. The composition of claim 1 wherein the additive has the formula:
CLAIMS SUPPORTED BY THE SUPPLEMENTARY DISCLOSURE

12. A non-opaque flame retardant aromatic carbonate polymer composition comprising in admixture an aromatic carbonate polymer and from 0.001 to about 2.0 parts per hundred parts of the aromatic carbonate polymer of an additive selected from the group consisting of a monomeric and polymeric alkali metal and alkaline earth metal aromatic sulfonesulfonate, and mixtures of these; said aromatic carbonate polymer and additive having a refractive index in the range of 1.54 to 1.65.

13. The composition of claim 12 wherein the monomeric metal aromatic sulfonesulfonates have the following formula:
R'(SO2)1R''(SO3M)1-6X0-11 wherein M is a metal selected from the group consisting of alkali metal and alkali earth metal, R' and R'' are independently selected from the group consisting of aryl radicals of 1-2 aromatic rings and an aliphatic radical of 1-6 carbon atoms, provided, however, that R' and R" together must contain at least one aromatic ring to which the SO3M group is attached, and wherein X is an electron withdrawing radical.

14. The composition of claim 13 wherein the electron withdrawing radical is selected from the group consisting of halo-, nitro-, trihalomethyl- and cyano- radicals and mixtures thereof.

15. The composition of claim 9 or 13 wherein the electron withdrawing radical is chlorine.

16. The composition of claim 12 wherein the polymeric metal aromatic sulfonesulfonates have at least 2 repeating units of the following formula wherein B is an aromatic sulfone of the following formula and A and C are dioxy radicals having 1-2 aromatic rings and are independently selected from the group consisting of and wherein M is a metal selected from the group consisting of alkali metal and alkaline earth meta, R is SO2, or an aliphatic radical selected from the group consisting of alkylene and alklidene radicals of 1-10 carbon atoms, X is a halo electron withdrawing radical, Y is an integer of 0-4, providing the sum of y is at least 1, m is 1, n is an integer of 0-20 and p is an integer from 2-200.

17. The composition of claim 16 wherein the additive is as defined in either claim 10 or claim 11.