CA1109176A

CA1109176A - Flame-retardant polyolefin polymeric compositions containing 3,9-halophenoxy-2,4,8,10-tetraoxa-3,9- diphosphaspiro(5.5)undecane-3,9-dichalcogen

Info

Publication number: CA1109176A
Application number: CA275,988A
Authority: CA
Inventors: James A. Albright; Chester J. Kmiec
Original assignee: Velsicol Chemical LLC
Current assignee: Velsicol Chemical LLC
Priority date: 1976-05-13
Filing date: 1977-04-12
Publication date: 1981-09-15
Also published as: FR2351148B1; BE854449A; IT1082057B; FR2351148A1; DE2719737A1; JPS5550497B2; JPS534061A; GB1570654A; NL7704714A

Abstract

ABSTRACT OF THE DISCLOSURE
Polymeric compositions comprising a polyolefin polymer and a flame retarding amount of a compound of the formula:

Description

1~91~

\
This invention relates to polymeric compositions, more particularly to synthetic resins comprising a polyolefin polymer and a flame retarding amount of a 3,9-bromophenoxy-

2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane-3,9-dichalcogen compound.
U~S. Patent 3,090,799 (hereinafter referred to as Wahl et al), discloses plasticizers comprising phosphoric acid esters of the generic formula:

O O

R10--P~ X / --OR2 in which Rl and R2 represent aliphatic, cycloaliphatic, heterocyclic or aromatic radicals, the hydrogen atoms of which can be substituted, for example, by halogen, ester, keto, nitrile, or amino groups. Rl and R2 can be identical or different. Because of the relatively high phosphoric acid content of the above compounds of Wahl et al, said compounds are stated by Wahl et al to impart a greater reduction in the combustibility for the same addition of plasticizer, in other words, smaller additions of Wahl et al's compounds are sufficient for producing the same effect.
The plasticizers of Wahl et al are stated as being useful in the production of shaped plastic compositions, such as foils, fiber and lacquer materials, as well as mold-ing materials, from organic compounds of high molecular weight, such as cellulose esters, cellulose ethers, polyvinyl com-pounds, for example, polyvinyl chloride, polyvinyl acetate, polystyrene, chlorinated rubber, alkyl resins, polyesters, polymers of acrylic acid and derivatives thereof, polyethylene polypropylene and other polymers and copolymers. Wahl et al further state that their phosphoric acid ester compounds may be used in any suitable thermoplastic resin.
The above discussion by Wahl et al is very generic and merely restates a general principle which is well known in the art of ~lame retardants, i.e., that phosphorus is capable when present in particular compounds of imparting flame `
retardant efficacy to materials treated therewith. However, it is also well known in the flame retardant art that there presently does not exist a universal flame retardant capable of imparting effective flame retardancy to all polymeric materials. Practitioners in the flame retardant art well recognize that although a compound may be an effective flame retardant for one polymer system, the same material may be ineffective for another. A flame retardant art practitiOner also knows that it takes inventive skill to determine what particular compound is capable of imparting flame retardant efficacy to a particular polymer system.
It has been discovered that a limited class of 3,9-halophenoxy-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane-

3,9-dichalcogen compounds impart an unusual high level of flame retardant efficacy to polyolefin polymers.
According to the present invention there is provided a polymeric composition comprising a polyole~in polymer and a flame retarding amount of a compound of the formula (I):

Brm X X

~ 0 ~ ~ I (I) wherein each X is identical and either oxygen or sulfur, pre-ferably oxygen, each m is an integer from 1 to 5, preferably from 1 to 4, and more preferably 3, n is an integer from 1 to 5, preferably from 1 to 4, and more preferably 3, I~ is also preferred that n equals m' it is thus especially preferred li~91~ , that m and n are both 3, whereby m plus n is 6. Further, it is preferred that both bromophenoxy groups be the same. Prefer-ably the compound contains at least ~5% by weight of bromine.
In another aspect of the invention there is provided a method of rendering a polyolefin polymer flame retardant which comprises incorporating a flame retarding amount of a compound of formula (I~ therein.
For purposes of illustration only, Table I, which follows is designated to further help describe the flame retardants of this invention and is neither meant nor should it be taken to be a complete listing of all the compounds within the scope of formula (I).
The numerical designations used in naming the compounds of this invention can be ascertained by reference to the following formula where the mem~ers of the hetero-cyclic and phenoxy rings are numbered.

~ O- Pg~ O _ ~ O~ 3- 0 ~ 4 r~

1~()917~i ~mmmmmmm ~ h ~llmmmmm h ~ h S~ h m ~mmmmmmm I I I I s~
~Illlmmm - ~ h S~ ~
H ~ mmmmmmm - ~ S l h h h ~mmmmmmm mmmmm . . - S~ h ~ h 5~ h S~
~mmmmmmm :~
i I t I I ~ ~
~Illllmm -~mmmmmmm X I O U~ O U~ O O U~
o C)

- 4 -11~91~6 The preferred compound within the scope o~ formula (I) is 3,9-bis(2',4',6'-tribromophenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane-3,9-dioxide.
In addition to the 3,9-bis-substituted compounds, an even larger number of 3,9-substituted compounds were the 3,9-substituents are different from each other are also included within the scope of this invention, The compounds of the present invention can be pre-pared by reacting a 3,9-dihalo-2,4,8,10-tetraoxa-3,9-diphos-phaspiro(5.5)-undecane-3,9-dioxide or disulfide with sub-stituted halophenols to yield the appropriate diphosphate ~-ester. The general reaction scheme is illustrated as follows:

Hal- P\ X /~ - Hal + ~ OU

~O-P~O~/\P-O-~ ~

wherein X has the meaning set forth above and wherein Hal indicates a halogen atom and Y is 1 to 5 bromo atoms. As an alternative reactant for the halophenol, the metal salts of the halophenol can be used. If it is desired that the two halophenol groups be different from each other, two different halophenol reactants should be employed. The reaction can be carried out by simply mixing the halophosphate and the halo-phenol or halophenol metal salt reactants together and heating the mixture gently at a temperature of 30 to 160C. for a period of time of from 1 to 12 hours. The above reaction can be conducted in the presence or absence of inert solvents.
Suitable inert solvents include aromatic solvents, e.g., benzene toluene, etc., and dipolar aprotic solvents, e.g., dimethyl~

formamide, dimethylsulfoxide, acetonitrile, and the iike.
Catalytic quantities of a metal salt or oxide such as magnesium oxide, magnesium chloride, calcium oxide, calcium chloride, titanium chloride, or vanadium acetate, or stochiometric quantities of a weak organic base such as pyridine or triethylamine, can be used to accelerate the completion of the reaction. The halophosphate starting reactant can be prepared by reacting pentaerythritol with a phosphorus oxyhalide.
The compounds within the scope of this invention can also be prepared according to the following reaction scheme:

~ OH + PXCl~ ~ OPC12 Reaction A Il 2 II + C(CHzH)4--~ ~ \ o X O

-Reaction B

wherein Y and X are as defined above. As an alternative reactant for the halophenol, the metal salts of the halo-phenol can be used. If it is desired that the two halophenol groups be different from each other, two different halophenol reactants should be employed. Reaction A can be carried out by refluxing the halophenol or halophenol metal salt with an e~cess amount of either phosphorous oxychloride or phosphorous thiochloride for a period of 1 to 48 hours, Catalytic quantities of a metal salt such as potassium chloride, sodium chloride, etc., or stochiometric quantities of a weak organic base such as pyridine or triethylamine, can be used to accelerate the completion of the reaction.

1~9~'76 To conduct Reaction B, two moles of the crude halo-phenyl dichlorophosphate or dichlorothiophosphate, II, are suspended or dissolved in an inert solvent. Suitable inert solvents include aromatic solvents, e.g., benzene, toluene, etc., and dipolar aprotic solvents, e.g., dimethylformamide, dimethylsulfoxide, acetonitrile, etc. One mole o~ penta-erythritol is added and the reactants are heated at 80 to 140C. for a period of 1 to 10 hours. The final product is separated by filtration, purified by standard techniques well known to those skilled in the art, e.g., washing, recrystallization, etc., and dried.
The flame retardants within the scope of this invention as well as mixtures thereof display an unobvious level of flame retardant efficacy in polyolefin polymeric compositions. Exemplary polyolefin polymers with which the flame retardants of this invention may be combined include homopolymers of ethylene, propylene, butene, and hexene and copolymers of two or more monomers, e.g., ethylene/propylene copolymers, ethylene/butene copolymers, and ethylene/hexene copolymers. A preferred class of polyolefin polymers which can be used with the flame retardants of this invention are propylene homo- and co-polymers thereof. A further des-cription of polyolefin polymers capable of being used in this invention can be found in Modern Plastics Encyclopedia, Vol, 52, No. 10A, McGraw-Hill, Inc., New York, ~ew York (1975), and the Encyclopedia of Polymer Science and Technology, Interscience Publishers, John Wiley & Sons, New York, N.Y.
(Vol, 2, Butylene Polymers- 1965, Vol. 6, Ethylene Polymers -1967 and Vol, 11, Propylene Polymers - lg69).
The flame retardants of this invention can be incorporated into or applied onto flammable polyolefin poly-meric material by techniques which are standard or known to g2 .
~ - 7 -`:
those skilled in the art. See for example, J. M. Lyons, "The Chemistry and Uses of Fire Retardants", Wiley-Inter-science, New York, 1970, and Z. E, Jolles, 'Bromine and Its Compounds", Academic Press, ~ew York, 1966. Depending on the substrate and the amount of flame re'ardancy desired, from about 1 to about 40 weight percent of the flame retardant compound of formula (I) can be incorporated therewith. How-ever, in most applications it is preferred to use from 1 to about 25 weight percent of said compounds within the scope of this invention. It should be noted that the optimum level of additive of the flame retardant within the scope of this invention depends upon the particular substrate being treated as well as the level of flame retardancy desired. For example, in polypropylene a flame retardant load level of from about 5 to about 25 percent by weight of the total polymeric com~
position is satisfactory.
In addition to the flame retardant compounds within the scope of this invention, the flame retardancy of a polymer can be further modified through the use of so-called synergists" or enhancing agents, although preferably no synergist or enhancing agent is used with the flame retardant phosphates of this invention. These "enhancing agents" com-prise the oxides and halides of groups IVA and VA of the Periodic Table, and are further described in Modern Plastics Encyclopedia, ibid., as well as U.S. Patents 2,993,924;
2,996,528, 3,205,196 and 3,878,165. Without limitation, preferred enhancing agents include Sb203, SbC13, SbBr3, SbI3, 2 3' 2 5~ ZnB04, BaB204.H20, 2.ZnO.3B203,3.5H O
and stannous oxide hydrate. The more preferred enhancing agent is antimony trioxide.
It is also within the scope of the present invention to employ other materials in the present invention compositions ~9:17~i where one so desired to achieve a particular end result.
Such materials include, without limitation, adhesion pro-motors; antioxidants; antistatic agents; antimicrobials colorants; heat stabilizers, light stabilizers and fillers.
The above mentioned materials, including filler, are more fully described in Modern Plastics Encyclopedia, ibid, The amount of the above described materials employed in the present invention compositions can be any quantity ~ which will not substantially adversely affect the desired results derived from the present invention compositions.
Thus, the amount used can be zero (0) percent, based on the total weight of the composition, up to that percent at which the composition can still be classified as a plastic. In general, such amount will be from about ~/O to about 75% and more specifically from about 1% to about 5~/O, The following examples are provided for the purpose of further illustration only and are not intended to be limitations on the disclosed invention. Unless otherwise specified, all temperatures are expressed in degrees centi-grade, all weights are expressed in grams; and all volumes are expressed in milliliters.
Example Synthesis of 3,9-bis(2',4',6'-tribromophenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane-3,9-dioxide (compound 1 of Table I): !
The sodium salt of tribromophenol(282 grams) was partially dissolved and suspended in one liter of acetonitrile.
To this mixture 119 grams of 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane-3,9-dioxide was added over a one-half hour period. ~ slight exotherm was noted. Upon complete addition, the mixture was stirred and heated to 70C. for three hours. The resulting solid white mass was filtered and the l~U~

product washed thoroughly with two liters of warm water. The solid was subsequently washed twice with boiling acetone to yield 322 grams (81 percent) of a white solid, m.p, 282~ to 286qC. Percent bromine calculated: 54.0, percent bromine found: 52.06.
Example 2 Synthesis of 3,9-bis(2',3',4',5',6'-pentabromo-phenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane-3,9-dioxide (compound 6, Table I):
The sodium salt of pentabromophenol (460 grams) was suspended in about 3 liters of acetonitrile in a 5-liter flask.
To the above suspension was slowly added 133.7 grams (0.45 mole) of 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5.5)undecane-3,9-dioxide. The reactants were stirred for half an hour and then heated gently. An additional liter of acetonitrile was added to the reaction system and then said system was heated up to 70C. and held at that temperature for 2.5 hours. The system was cooled, filtered, reslurried with water, refiltered with a centrifuge, and then air dried. The dried residue was given a boiling acetone wash, filtered through a centrifuge, and then dried at 95C. A yield of 69.7 percent (377 grams) was obtained. Melting point: 324 to 326¢.
Comparative Example 3 Synthesis of 3,9-bis(2',3',4',5',6'-pentachloro-phenoxy)-2,4j8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane-3,9-dioxide.
Pentachlorophenol (97 grams, 0.364 mole), potassium chloride (3.6 grams), and phosphorus oxychloride (447 grams) were heated to the solutions refluxing temperature in a l-liter ~lask equipped with a magnetic stirrer. The reaction was re-fluxed for 16 hours, cooled to room temperature, and then lS~9176 filtered. Excess phosphorus oxychloride was removed under vacuum. The pentachlorophenyl dichlorophosphate residue (125 grams, 0.326 moles) was dissolved in toluene. Into this solution was added 22.2 grams (0.163 mole) of penta-erythritol. This reaction system was heated to reflux, held at the reflux temperature 2.75 hours, cooled to room tempera-ture, and then filtered. The residue was air dried and then dried for 2 hours at 110C. Yield: 117 5 grams (95.3%), Percent chlorine: theory: 46.9~/o' found: 46.44% melting point: greater than 380C.
Comparative Example 4 3,9-bis-~2 14',6'-trichlorophenoxy)-2, 4 ~ 8,10-tetraoxa-3,9-di-phosp~aspiro(5.5)undecane-3,9-dioxide.
The sodium salt of trichlorophenol (253 grams) was partially dissolved and suspended in 1 liter of acetonitrile.
To this mixture 171 grams of 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane-3,9-dioxide was added over a one-half hour period. A slight exotherm was noted. Upon con~
plete addition, the mixture was stirred and heated to 70C.
for three hours. The resulting solid white mass was filtered and the product washed thoroughly with warm water. The solid was subsequently washed twice with cold acetone to yield 181 grams (51 percent) of a white solid, m.p. 283 to 28~C, Percent chlorine calculated: 34.5 percent chlorine found:
30.9.
Comparative Example 5 3,9-bis(4'-chlorophenoxy~-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane-3,9-dioxide Phosphorus oxychloride (3 kgm), potassium chloride ~40 grams), and p-chlorophenol (309 grams, 2.4 moles) were magnetically stirred in a 3 liter flask and heated to reflux.

11~917~

The reactants were refluxed for 12.75 hours and then cooled to room temperature. The reactants were filtered and excess phos-phorus oxychloride was removed under vacuum. The crude product (538 grams; 2.19 moles) was transferred to a 2 liter flask into which was also added 502 ml of toluene and 152 grams (1.09 moles) of pentaerythritol. These reactants were heated to reflux and then held there for 5.25 hours. The reactants were then cooled to room temperature, filtered, and the residue dried under vacuum at 80C. The product was washed with 3 liters of a 5~/O aqueous solution of acetone, filtered, and then air dried. Yield: 348 grams (66.5%), Acid number:
0.86, Percent chlorine: theory: 14.~/o; found: 15.06%.
Exam~le 6 A solution of 600 grams of polystyrene, 2670 grams of methylene chloride, and 60 grams of hexane, and 5 parts per hundred resin (phr) of Example 1 was prepared. To the above solution was added 3 grams of dicumyl peroxide as a flame retardant synergist. This mixture was poured into an aluminum dish and the methylene chloride was allowed to evaporate, Following this, the casting was steamed to produce a crude foam. This foam was then cut into sufficient specimens of appropriate sizes in order to subject said foam to various tests and the data obtained therefrom are reported in Table II.
The same processing conditions as above were used to maXe additional polystyrene foam samples having different flame retardant load levels. These samples were tested in the same manner and the results obtained are also tabulated in Table II, 17~

The flame retardant of Example I (4~O of the total mixture by weight) was dry mixed with high impact polystyrene (HIPS) resin (52% by weight), and ~O by weight antimony oxide (Cosden 825* TV-K brand HIPS Cosden Oil & Chemical Co., Big Springs, Texas). The mixture was melt blended in a compounding machine under the following conditions: temperature: 240C., rpm: 100 to 120, and mixing time: 2 to 3 minutes (Prep-Center*
brand compounding machine, C.W. Braebender Instruments, Inc., S. Hackensack, New Jersey). The discharge mass was cooled, ground, let down to a flame retardant load level of l~/o by weight and 3.6% by weight antimony oxide by dry blending the ground concentrate discharge mass with the HIPS resin, and then injection molded using a 30-ton Newbury 1 ounce injection molding machine under the following parameters: screw speed:
250 rpm, injection pressure: initial: 2000 pounds per square inch (psi), internal barrel temperature: rear zone: 440F., front zone: 470F.; cycle time: 60 seconds (sec.); total injection time: 20 sec., total stroke time: 5 sec. The final HIPS polymeric composition was subjected to various tests' and the data obtained therefrom are reported in Table II.
The same processing conditions as above were used to make additional HIPS Polymeric samples having different flame retardant and antimony oxide load levels. Using the same injection molding conditions as above save that the internal barrel temperature rear and front zones were 420 and 470F.
respectively, HIPS samples were also prepared with neither flame retardant additive nor antimony oxide present. The absence of the prior melt blending step and the difference in the rear and front zone internal barrel temperatures have no impact on the flame retarding efficacy of the HIPS base resin.

* trademark B

11'~176 These samples were tested in the same manner and the results obtained are also tabulated in Table II.
Example 8 The flame retardant o~ Example l (36% of the total mixture by weight) was dry mixed with low density polyethylene (LDPE) resin (64% by weight) (Union Carbide 3900 brand LDPE, Union Carbide Corp., New York, New York). The mixture was melt blended in a Brabender Prep-Center compounding machine under the following conditions: temperature: 220C., rpm: lO0~
and mixing time: 2 to 3 minutes. The discharge mass was cooled, ground, let down to a flame retardant load level of l~/o bv weight flame retardant by dry blending the ground concentrate discharge mass with the LDPE resin, and then injection molded using a 30-ton Newbury l ounce injection molding machine under the following parameters: screw speed: 250 rpm; injection pressure: initial: 2000 psi; internal barrel temperature:
rear zone: 410F., front zone: 440 F.; cycle time. 60 sec,, total injection time: 20 sec., total stroke time: 3 sec. The final LDPE polymeric composition was subjected to various tests and the data obtained therefrom are reported in Tables II and III.
Using the same injection molding conditions as above, additional LDPE samples were prepared without any flame retardant additive present. The absence o~ the prior melt blending step has no impact on the flame retarding efficacy of the LDPE base resin. These samples were tested in the same manner and the results obtained are also reported in Tables II and III.

Example 9 The flame retardant of Example 1 (3~/O of the total mixture by weight) was dry mixed with polypropylene resin (7~/O by wei~ht) (Hercules 6823 brand polypropylene, Hercules, Inc., Wilmington, Delaware). The mixture was melt blended in a Brabender Prep~Center compounding machine under the following conditions: temperature: 220C.; rpm: 100, and mixing time:
1 to 2 minutes. The discharge mass was cooled, ground, let down to a flame retardant load level of 12.5% by weight flame retardant by dry blending the ground concentrate discharge mass with the polypropylene resin and then injection molded using a 30-ton Newbury 1 ounce injection molding machine under the following parameters: screw speed: 250 rpm' injection pressure: initial: 2000 psi, internal barrel temperature:
rear zone: 410F., front zone: 440 F,; cycle time: 45 sec., total injection time: 20 sec.; total stroke time: 4.5 sec.
The final polypropylene polymeric composition was subjected to various tests and the data obtained therefrom are reported in Tables II and III.
The same processing conditions as above, save that in the case of compound of Example 2 the compounding parameters were: temperature: 225C., rpm: 120, and mixing time: 2 to 3 minutes and cycle time was 60 seconds and the stroke time was 4.5 seconds, and in the case of compound of Example 3 the mixing time was 2 to 3 minutes, the cycle time was 60 seconds and the total stroke time was 4 seconds. The different parameters used in preparing these additional polypropylene polymeric samples have no impact on the flame retardant efficacy of the flame retardant additive. Also, using the same-injection molding conditions as above, additional polypropylene poly-meric samples were prepared without any flame retardant additive present, The absence of the prior melt blending step has no impact on the flame retardant efficacy of the flame retardant additive. These samples were tested in the same manner and the results obtained are also reported in Tables II and III.
Table II clearly demonstrates that the flame retardant compounds within the scope of this invention, as exemplified by Example 1, are not universal flame retardants capable of imparting effective flame retardancy to all polymeric mate-rials treated therewith. However, Table II clearly depicts this invention's discovery of the unobvious flame retardant efficacy of the flame retardant compounds within the scope o~ this invention, as exemplified by compounds of Examples 1 and 2 in polyolefins, as exemplified by low density poly-ethylene and polypropylene~ As vividly displayed in Table II, of the various polymeric compositions containing an exemplary flame retardant compound within the scope of this invention, only flame retarded polyolefins exhibit an exceptionally high increment in Oxygen Index. These beneficial results are achieved without the use of an "enhancing" agent.
Other flame retardant compounds within the scope of this invention which also impart an exceptionally high incre-ment in Oxygen Index to flame retarded polyolefins include 3,9-bis(2',4' r 5',6'-tetrabromophenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane-3,9-dioxide, and 3,9-bis(2',4',6'-tribromophenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)-undecane-3,9-disulfide.
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Example 10 The compound of Example 4 (36% of the total mixture by weight) was dry mixed with LDPE resin (64% by weight) (Union Carbide 3900 brand LDPE, Union Carbide Corp., ~ew York, New York). The mixture was melt blended in a Brabender Prep-Center compounding machine under the following conditions:
temperature: 220~C., rpm: 100; and mixing time: 2 to 3 minutes.
The discharge mass was cooled, ground, let down to a flame retardant load level of l8/O by weight flame retardant by dry blending the ground concentrate discharge mass with the LDPE
resin, and then injection molded using a 30-ton Newbury 1 ounce injection molding machine under the following para-meters: screw speed: 250 rpm; injection pressure: initial:
2000 psi; internal barrel temperature: rear zone: 410F., front zone: 440F.; cycle time: 60 sec., total injection time: 20 sec., total stroke time: 3.5 sec. The final LDPE
polymeric composition was subjected to various tests and the data obtained therefrom are reported in Table III.
The difference in parameters used to prepare the various LDPE samples of Examples 8 and,10 has no impact on the flame retarding efficacy of the flame retardant additive.
Example 11 The compound of Example 4 (25% of the total mixture by weight) was dry mixed with polypropylene resin (75% by weight) (Hercules 6823 brand polypropylene, Hercules, Inc , Wilmington, Delaware). The mixture was melt blended in a Brabender Prep-Center compounding machine under the following conditions: temperature: 220C., rmpo 100, and mixing time:
2 to 3 minutes. The discharge mass was cooled, ground, let down to a flame retardant load level of 12.5% by weight flame retardant by dry blending the ground concentrate discharge mass with the polypropylene resin, and then injection molded ~,A

9~7~

using a 30-ton Newbury 1 ounce injection molding machine under the following parameters: screw speed: 250 rpm' injection pres-sure: initial: 2000 psi, internal barrel temperature: rear zone: 410 F., front zone: 440F., cycle time: 60 sec., total injection time: 20 sec.' total stroke time: 4.5 sec.
The final polypropylene po.lymeric composition was subjected to various tests and the data obtained therefrom are reported in Table III.
The same processing conditions as above, save that the compounding temperature was 210C,, the rpm was 120, and the total stroke time was 4 seconds, were used to prepare additional polypropylene samples containing compound B. The difference in parameters used to prepare the various polypro-pylene samples of Examples 9 and 11 has no impact on the flame retarding efficacy of the polypropylene base resin.

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i7~ii Based on this disclosure, many other modifications and ramifications will naturally suggest themselves to those skilled in the art. These are intended to be comprehended as within the scope of this invention.

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Claims

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

1. A polymeric composition comprising a polyolefin polymer and a flame retarding amount of a compound of the formula:

wherein each X is identical and is oxygen or sulfur, m is an integer from 1 to 5 and n is an integer from 1 to 5.

2. A polymeric composition according to claim 1, wherein said compound contains at least 45%, by weight, bromine.

3. A polymeric composition according to claim 1 or 2, wherein m is an integer from 1 to 4 and wherein n is an integer from 1 to 4.

4. A polymeric composition according to claim 1 or 2, wherein m equals n, and m and n are integers from 1 to 4.

5. A polymeric composition according to claim 1 or 2, wherein each bromophenoxy group is the same and m and n are integers from 1 to 4.

6. A polymeric composition according to claim 1 or 2, wherein m and n are both 3.

7. A polymeric composition according to claim 1 or 2, wherein m plus n is 6.

8. A polymeric composition according to claim 1, wherein said compound is selected from 3,9-bis(2',4',6'-tri-bromophenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)-undecane-3,9-dioxide; 3,9-bis(2',3',4',5',6'-pentabromo-phenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane-3,9-dioxide and 3,9-bis(2',4',5',6'-tetrabromophenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane-3,9-dioxide, and 3,9-bis(2',4',6'-tribromophenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane-3,9-disulfide.

9. A polymeric composition according to claim 8, wherein said polyolefin polymer is selected from polypro-pylene, polyethylene and copolymers thereof.

10. A polymeric composition according to claim 9, wherein said compound is 3,9-bis(2',4',6'-tribromophenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro(5.5)undecane-3,9-dioxide.

11. A polymeric composition according to claim 1 or 2, wherein said compound is present in an amount from about 1 to about 40 weight percent of the total composition.

12. A method of rendering a polyolefin polymer flame retardant which comprises incorporating in said polymer a flame retarding amount of a compound of formula:

wherein each X is identical and is oxygen or sulphur and m and n are integers from 1 to 5.

13. A method according to claim 12, wherein said com-pound contains at least 45%, by weight, of bromine.

14. A method according to claim 12 or 13, wherein m and n are integers from 1 to 4.

15. A method according to claim 12 or 13, wherein m and n are equal, and are integers from 1 to 4.

16. A method according to claim 12 or 13, wherein each bromophenoxy group is the same and m and n are integers from 1 to 4.

17. A method according to claim 12 or 13, wherein m and n are both 3.

18. A method according to claim 12 or 13, wherein m plus n is 6.

19. A method according to claim 12 or 13, wherein from 1 to 40%, by weight, of said compound is incorporated in said polymer.