NL8004920A - Flame retardant resin compsn. - comprising polyphenylene ether, polystyrene and synergistic mixt. of a phosphine oxide and phosphonate - Google Patents

Abstract

Resin compsn. comprises a homogeneous blend of 10-90 pts.wt. polyphenylene ether and 90-10 pts.wt. polystyrene; and a flame retardant amt. of a mixt. of (A) (R1)2POR2 (where R1 and R2 are 4-12C alkyl, 5-8C cycloalkyl, halo(1-3)phenyl, 1-4C omega-cyano-alkyl or benzyl); or (R3)2POXPO(R3)2, (where R3 is 5-8C cycloalkyl or 1-4C omega-cyano-alkyl and X is (CH2)n (n is 1-6), (I) (where R4 is 1-4C alkyl and y is 0-4), and (B) (II) or (III) (where R5 is phenyl, benzyl or 1-4C alkyl(1-3)-benzyl and Y is (IV) (where R6 is 1-4C alkyl and x is 0-4)). (A) and (B) are in the wt.ratio 1:3-3:1. Mixt. of (A) and (B) provides a flame retardant effect at a lower concn. than obtainable using (A) or (B) alone.

Description

* '4 VO 913

Flame-retardant, rubber-modified polyphanylene ether resin compositions.

The invention relates to flame-retardant polyphenyl boron ether resin compositions containing an effective flame retardant amount of a compound selected from CR] 3P = 0 Cl] 5 wherein R alkyl having about 1 to 6 carbon atoms, halosalkyl having about 1 - S carbon atoms, halophenyl having about 1 to 3 halogen atoms, benzyl, alkyl benzyl having 1-3 alkyl substituents each having about 1-4 carbon atoms or cycloalkyl having about 5 * 8 carbon atoms; 10 0 1 "2 CR] -PR C21 1 ά where R is selected from alkyl of 1 τ 4 carbon atoms, cycloalkyl of 5-8 carbon atoms, phenyl, halophenyl of 1-3 halogen atoms, alkoxyphenyl in which each alkoxy group contains 1-4 carbon - 15 atoms, carboxyalkyl in which alkyl has 1? 4 carbon atoms, 2 R is selected from hydrogen, alkyl of 1-12 carbon atoms,

O 1 -cyanoalkyl wherein alkyl has 1 to 4 carbon atoms, benzyl, alkyl benzyl with 1 to 5 alkyl substituents, each having 1 to 4 carbon atoms, and hydroxyalkyl with 1 to 4 carbon atoms, with 1 2 20 provided that in the case R is carboxyalkyl , R does not represent hydrogen or benzyl; CNC-CH 2 CH 2 -5Y-P-Y-P-5-CH 2 -CN 3 C 3 wherein the group Y is selected from 25 C 1 alkylene of 1-4 carbon atoms; C27 substituted xylylene of formula 5, wherein each X represents a halogen atom or an alkyl group of 1-4 carbon atoms and m is an integer from 1 to 4, provided that when none of X represents halogen, the methylene groups are 8004920 - 2 - meta-toothed to each other, · C3J is the group of the formula 6, wherein p represents an integer of at-3 at least 1, R alkyl of 1-4 carbon atoms, and q represents 0 or 4-p; 5 (41 the group of formula 7j or C5) the group of formula 8j CR4) P-Q-PCR4) C4) 4 where R. is selected from cycloalkyl of 5-8 carbon atoms, phenyl, carbamoylethyl, and carboalkoxyethyl, wherein the alkoxy group contains 1-4 carbon atoms and wherein Q is selected from alkylene of 1-6 carbon atoms, the group of formula 9 wherein R5 is alkyl with 1-4 carbon atoms and n an integer of 1 - 4 isj or the group of formula 10, provided that when R is 15 carboalkoxyethyl and 0 represents the group of formula 9, n is 4j and as a fifth possibility, a combination of C 1) a phosphine oxide 1 of either formula 2, wherein R and R are each selected from alkyl of 4-12 carbon atoms, cycloalkyl of 5-8 carbon atoms, phenyl, halophenyl of 1-3 halogen atoms, in especially chlorine or bromine, & - - cyanoalkyl of 1-4 carbon atoms, and benzyl, or formula 4, wherein R is selected from cycloalkyl of 5-8 carbon atoms and cyί-cyanoalkyl of 1-4 carbon atoms, and Y the above mentioned has meanings, and Ciil has chosen a phosphonate, 6 25 n from a compound of formula 11 wherein R represents phenyl, benzyl or alkylbenzyl with 1-3 alkyl groups each containing 1-4 carbon atoms and a compound of formula 12 wherein Z is xylylene or alkyl-substituted xylylene with 1-4 alkyl groups which each contains 1-4 carbon atoms, when the phosphine oxide of formula 1 is used, trisCn-butyl) phosphine oxide and tris (2,4,6-trimethylbenzyl) phosphine oxide are preferred.

TrisC-butylphosphine oxide is a known compound prepared according to the method described by Davies et al., 35 J. Chem. Soc. 1929, p. 33, tri-n-butylphosphine is reacted with 8004920 *% - 3 - reacting with nitric acid. Other alkylphosphine oxides of formula 1 are prepared in a similar manner.

Tris (2,4,6-trimethylbenzyl) phosphine oxide is prepared according to methods described in U.S. Patent 5 4,053,518,

Methods for preparing compounds of formula 1 are described in Berlin et al., J. Org. Chem. 32, 129 (1967) Carson et al., J. Org. Chem. 26, 1467 (1961); Buckler, J. Am. Chem.

Soc. 84, 3093 (1962).

When the phosphine oxide of formula 2 is selected, the following compounds are preferred: 1) methyl-bis- (2-carboxyethyl} phosphine-oxide (2) hydroxymethyl-bis- (cyclohexyl) -phosphine oxide (3) benzyl-bis- (cyclohexyl) phosphine oxide.

The phosphine oxide compounds of formula 2 are described in one or more of the following references: German Gffenlegungsschrift 2,540,283; U.S. Patents 4,061,681 and 3,341,625; and J. Org. Chem. 24, 2013 - 2015 (1959).

The compound "i-hydroxymethyl-bis-20 (cyclohexyl) phosphine oxide" illustrated in Example 6 is a new compound.

The phosphine oxide compounds of formula 3 are described in U.S. Pat. Nos. 3,284,543 and 3,835,119,

Compounds of formula 3 wherein Y is alkylene with 1? 4 carbon atoms can be prepared by oxidation of the corresponding bisphosphine compound (see Chatt et al., J. Chem.

Soc, 1960, p. 1378, and Hewertson et al., J. Chem. Soc. 1960, p.

1490) with hydrogen peroxide or oxygen; see U.S. Patent 3,032,589 or Berichte 92, 3175 (1954). The other compounds can be readily prepared by reacting the corresponding halomethyl intermediate with bis (2-cyanoethyl) phosphine oxide according to the formula sheet reaction scheme A, in which AR represents an aromatic ring system, * '**

The compounds of formula 4 are described in U.S. Pat. Nos. 3,284,543; 3,976,685; 4,009,207; and 8004920-4-4,017,455.

Compounds of formula 4 wherein Q represents alkylene can be prepared by oxidation of the corresponding bisphosphine compound (see Chatt et al., J. Chem. Soc. 1960, p. 1378, 5 and Hewertson et al., J, Chem. Soc 1960, p. 1490) with hydrogen peroxide or oxygen, see U.S. Patent 3,032.5B9 4 and Berichte 92, 3175 C19543. On the other hand, in the case where R represents carbamoylethyl, the corresponding bis- (2-cyanoethylphosphine oxide) is successfully hydrolyzed to the carboxylic acid, esterified with a low aliphatic alcohol and then amidated with ammonium hydroxide.

Preferred compounds for the combination of the fifth possibility include!

Cyl phosphine oxides selected from 15 tris- (2-cyanoethyl-3-phosphine oxide, tris-C-benzyl 3-phosphine oxide, trl-phenyl-phosphine oxide, tris- (p-chlorophenyl-3-phosphine oxide, tris- (n-octyl 3-phosphine oxide, 20-benzyl-bis- (2-cyano-bis- (2-cyanobis)) (cyclohexy13 phosphine oxide, bis-Z * Cdicyclohexylphosphinyl3methyl-7-terephthalate, ethylene-bis-ZT bisC2-cyanoethyl-phosphine-oxide-2,3,5,6-tetramethyl-1,4-xylylene-bis-bis (2-cyanoethyl-25-phosphine) iiphosphonates selected from benzyl neopentylene phosphonate / phenyl neopentylene phosphonate, 2,4,6-trimethylbenzyl neopentylene phosphonate,

Cp-phenylenedimethylene3-bis- ^ 2, 2-dimethyltrirethylethylene phosphonate J, (2,5-dimethyl-1,4-phenylenedimethylene-1-bis-2U-2-dimethyl-trimethylene-phosphonate).

Flame retardant rubber modified polyphenylene ether 8004920 resin compositions are prepared by incorporating therein an effective flame retardant amount of a compound of said formulas,

The polyphenylene-5 ether resin compositions suitable for use in the invention are described in U.S. Patent 4,024,093, the contents of which are to be considered incorporated herein. Essentially, these resins comprise about 10 - 90 parts by weight of polyphenylene ether and about 90 - 10 parts by weight of a styrene polymer. Preferably, the polymer contains about 50-30 parts by weight of polyphenylene ether and about 50-20 parts by weight of styrene polymer.

The styrene polymer is a rubber-modified, highly impact-resistant polystyrene. The resins are blends of the two polymers, which are mutually soluble and form a homogeneous polymer composition.

The flame retardant compounds are used in an amount sufficient to obtain a self-extinguishing composition, as will be described below. be defined, applied. Generally, however, the amount used is at least about 4% by weight based on the weight of the resin, preferably at least about 6%. For possibility five, the weight ratio of phosphine oxide to phosphonate is preferably about 3/1 to 1/3, most preferably about 1/1,

The flame-retardant compounds can be incorporated into the polymer by any method known per se; however, it is preferred that the compounds be incorporated by grinding them in the polymer on a known two-roll mill or by mixing them dry with the polymer, followed by extrusion.

The invention includes the possibility of incorporating additional ingredients such as plasticizers, dyes, pigments, heat and light stabilizers, antioxidants, anti-static agents, photochromic materials and the like,

The invention is further illustrated by the examples. All parts and percentages are by weight, unless stated otherwise.

8004920 «- 8 *

Example I

. A total amount of 10 g of a mixture of 50 parts of palyphenylene ether / 50 parts of rubber-modified impact-resistant polystyrene, containing 6% by weight of the compounds of Formula 1 shown below, was extruded at 290-300 ° C by melt index. equipment [described in ASTM D-1238). The cylindrical extrudate about 7.6-12.7 cm in length and about 0.6 cm in diameter was subjected to the following flame power test described in Underwriters Laboratories Test UL-94, Vertical Test, Method 3.10-3, [September 1973], The polymer sample clamped in a vertical position was ignited with a 3/4 'blue flame [methane or natural gas) for 10 seconds, and the flame removed. When the flame extinguished within 25 seconds, the sample was again ignited for 10 seconds and the flame removed again. The time to extinguish the flame was again recorded. When the time to extinguish the flame was no more than 5 seconds for both times the flame was applied, the sample was rated V ”0j when the time to extinguish the flame for either the first or the second the time the flame 20 was applied was between 5 and 25 seconds, the sample was rated V "1. When a sample exhibits quench times" of more than 25 seconds for both times the flame was lit, "it was qualification free-burning CFBC in this case, the sample was considered to have failed according to the test.

The following compounds were rated V-0 or \ M according to the above test when incorporated into the resin in an amount of 6% by weight: triphenylphosphine oxide, 30 tris- [p ”chlorobenzyl) phosphine oxide, tris” (n-butyl) ) phosphine oxide) tris "C 1 propyl) phosphine oxide tris- (2,4S-trimethylbenzyl) phosphine oxide (tri * triS" Ccyclohexyl) phosphheoxide (tris-chloromethyl) phosphine oxide.

8004920 • * - 7 -

Example II

* ........ '»

The procedure of Example I was repeated, except that the mixture contained 70 parts of polyphenylene ether resin and 30 parts of polystyrene. In a study with a concentration of 4% by weight, the compounds of the test received a qualification V-0 or V-1.

Example III

According to the method of example I, a determination was made of the flame power care of a highly impact-resistant polystyrene containing 20% by weight of the compounds mentioned in example I.

Determined according to the UL-94 procedure, the samples were free-burning CFB).

Examples Γ-III show that Cl] for a 50/50 mixture of polyphenylene ether resin, the compounds of formula 1 must be used in a concentration of at least 6% by weight 15 to be effective flame retardants (2] for a 70/50 The mixture requires at least 4% by weight of the compounds and C3] the compounds are not effective flame retardants for polystyrene, even at a concentration of 20% by weight.

Example IV

Methy1-bis-C 2 -carboxyethyl] phosphine oxide:

Methyl bis-C2-cyanoethyl] phosphine oxide was hydrolyzed in concentrated hydrochloric acid to give a white solid product, mp 174-176 ° C. The neutralization equivalent C theory 104] was 106.6, 105.4, on average 106.

Example V

2.4,6-trimethylbenzyl-bis-C cyclohexy1] phosphine oxide:

Prepared by the method of U.S. Pat. No. 4,061,681], 3

4G, 9 g of dicyclohexylphosphine in 50 cm of isopropanol 30 was reacted at 40 ° C with 15.8 g of a 38% formaldehyde solution.

When the reaction was completed [absence of P-H band in the infrared spectrum], 16.9 g of 2,4,6-trimethylbenzyx chloride was added and the reaction mixture was added at 5 ° C for 22 hours. heated.

A viscous oil was separated from the reaction mixture, which crystallized on standing to form a white solid 8004920-βε with a melting point of 139-143 ° C. Recrystallization from hexane gave a product with a melting point of 142-145 ° C.

Example VI

-hydroxymethyl-bis-C cyclohexy13phosphine oxide: Dicyclohexylhydroxymethylphosphine was oxidized with 30% hydrogen peroxide in acetic acid and the product isolated as an oil. This crystallized on standing off. During the recrystallization from benzene, a white solid with a melting point of 154 DEG-157 DEG C. was obtained,

Example VII

Benzyl bis- (cyclohexyl] phosphine oxide:

A mixture of 6.85 g of dicyclohexylmethylphosphorus and 4.0 g of benzyl chloride was heated at 160 ° C under nitrogen for 2 hours. The crystalline product was recrystallized from heptane to obtain 5.4 g of a white solid, mp 147-149 ° C.

Example VIII

2-cyanoethy1-bis-C n-propy13phosphine oxide: 3

To 6.88 g, 0.04 mol, dipropyl cyanoethyl phosphine in 25 cm glacial acetic acid, 5.67 g, 0.05 mol, 30% hydrogen peroxide was added at 60 ° C. The reaction mixture was heated at 75 ° C for 30 minutes to yield 7.5 g of product.

Example IX. Diphenylphosphine oxide: Diphenylphosphoric chloride was prepared according to the method of J. Org.

Chem. 24, 2013 (19593 hydrolyzed to provide the title compound.

Example X.

According to the procedure of Example 1, the following compounds of formula 2 were qualified as V-0 or V-1 according to the test described when they were incorporated into the resin in an amount of 6% by weight: Ffc2. .....

1.-CH2CH2C02H -CH3 35 2. cyclohexyl 2,4,6-trimethylbenzyl 8004920 * * - 9 -

3. cyclohexyl -CH 2 OH

4. cyclohexyl benzyl

5. n-C3H7- -CH2CH2CN

6. phenyl -H

Cyclohexyl -H

8. p-chlorophenyl -H

9. p * methoxyphenyl -H

10. n * C3H7 n'CaH17 11. -CH2CH2CO2H n "C7H15

Example XI

The procedure of Example X was repeated, except that the mixture contained 70 parts of polyphenylene ether resin and 30 parts of polystyrene.

In a test at a concentration of 4% by weight, the compounds had the qualification V-0 or V-1 according to the conducted experiment.

Example XII

Following the procedure of Example X, a determination was made of the flame power score of a highly impact resistant polystyrene containing 20% by weight of the indicated compounds. Determined according to the UL-94 procedure, the samples were free-burning CFB], 20

Examples X-XII show that for a 50/50 mixture of polyphenylene ether resin, Cl], the compounds of formula II must be used at a concentration of at least 6% by weight to be effective flame retardants C23 for a 70/30 mixture 25 requires at least 4% by weight of the compounds; and C3] the far

bonds are not effective flame retardants for polystyrene, even at a concentration of 20% by weight, nExample XIII

1,3-bis-, his His- (2 ë * cyanoethyl] phosphonylmethylene J7-2.4.5,6-tetra-30-chlorobenzene of formula 13.

15.4 g, 0.049 mol, 1,3-bis-Chloromethyl-2,4,5,6-tetrachlorobenzene was reacted with 50 ° C for 50 minutes. 3 15.7 g, 0.1 mole, bis- (2-cyanoethyl] phosphine oxide in 2 .0.-cm methanol. During the reaction, a solution of 6.4 g of potassium hydroxide in 80 cm methanol was added. The reaction mixture was refluxed for 45 minutes for 10 minutes and cooled. The product was isolated as a solid, m.p. 320-332 ° C.

Example XIV

According to the procedure of Example I, the compounds

of the formulas 14-19, falling under the compounds of the formula 3, qualified as V-0 or V-1 according to the test when they were incorporated in the resin in an amount of B% by weight. Example XV

The procedure of Example XIV was repeated, except that the mixture contained 70 parts of polyphenylene ether resin and 30 parts of polystyrene. In a test measured a concentration of 4% by weight, the compounds of the test had the qualifications V-0 or V-1.

Example XVI

According to the method of Example XIV, a determination of the flame power score of a highly impact-resistant polystyrene containing 20% by weight of the said compounds was carried out. Samples determined according to the UL-94 procedure were free-burning (FB).

Examples XIV-XVI show that (13 for a 50/50 blend of polyphenylene ether resin, the compounds of formula 3 must be used at a concentration of at least B% by weight to be effective flame retardants; (2II for a 70 / The mixture requires at least 4% by weight of the compounds, and (3) the compounds are not effective polystyrene flame retardants, even at a concentration of 20% by weight,

Example XVII

Ethylene bis-Cdicyclohexylphosphine oxide].

40 g, 0.2 mole, dicyclohexylphosphine was reacted for 2 hours at 90-100 ° C with 1B g, 0.1 mole, ethylene dibromide to form ethylene bis-Cdicyclohexylphosphine). The phosphine compound was then oxidized with 25 g of 30% hydrogen peroxide to form the phosphine oxide. The crude product was crystallized from isopropanol / water to give 20 g of the title compound 35, mp 199 DEG-201 DEG.

8004920 3 * f - 11 -

Example XVIII

Bis -, "Cicyclohexylphosphinyl] methyl 7-terephthalate:

6.1 g, 0.03 mole, terephthaloyl chloride in 30 ml of benzene were added dropwise at a temperature of not more than 50 ° C to a mixture of dicyolohexyl hydroxymethylphosphine oxide and triethylamine. The reaction mixture was refluxed for 30 minutes and the product filtered, washed with water and dried; the melting point was 225-228.5 ° C.

Example XIX

According to the procedure of Example I, the following compounds of formula 4 were qualified by test with V-0 or V-1 when incorporated in the resin in an amount of 6% by weight, R 4 _ 1, 15 1. phenyl -CH2CH2-2, phenyl -CH2 -3. Cyclohexyl -CH2CH2-4. H2IMCOCH2CH2- CH2CH2-5, H2NCOCH2CH2 formula 20 20 S. CH3OCOCH2CH2 formula 21 7. cyclohexyl. formula 22

Example XX

The procedure of Example XIX was repeated, except that the mixture contained 70 parts of polyphenylene ether resin and 30 parts of polystyrene 25 '. In a study with a concentration of 4% by weight, the compounds of the test received a qualification of V-G or V-1.

Example XXI

Following the procedure of Example XIX, a determination of the flame power score of a highly impact resistant poly-styrene containing 20% by weight of the stated compounds was made. Determined according to the UL-94 procedure, the samples were free-burning CFB).

Examples XIX-XXI show that for a 50/50 blend of polyphenylene ether resin, the compounds of formula IV in a concentration of at least 6% by weight must be used to be 8004920-12 effective flame retardants; (2) for a 70/30 mixture, at least 4% by weight of the compounds is required. and C33 the compounds are not effective flame retardants for polystyrene, even at a concentration of 20% by weight.

5 Examples XXII - XXV

A total of 10 g of a 50/50 blend of polyphenylene ether / rubber modified impact resistant polystyrene containing the flame retardant was dry blended and extruded through a melt index equipment (described in ASTM D-1238) at 290-10300 ° C. The cylindrical extrudate with a length of about 7.6 - 12.7 cm and a diameter of about 0.6 cm was tested in the following flame power test, described in Underwriter's Laboratories Test UL-94, Vertical Test Method 3.10 - 3.15 (September 1973] The above polymer sample was clamped in a vertical position, ignited with a 1.9 cm blue flame (methane or natural gas) for 10 seconds, and the flame removed.When the flame extinguished within 25 seconds, it was again for 10 seconds ignited and the flame removed again. The time to extinguish the flame was re-recorded. When the time to extinguish the flame was not more than 5 seconds for both times the flame was applied, the sample was rated V-0 When the time to extinguish the flame for either time the flame was applied was between 5 and 25 seconds, it was rated V-1. When a sample has a quench time More than 25 seconds before each time the flame was lit, it was rated free-burning (FB) and considered to have failed according to this test.

Table A shows the data obtained with tris- (2-cyano-30 ethyl] phosphine oxide (A) and benzyl neopentylene phosphonate (B).

* 8004920 * »- 13 -

Table A

Evaluation of Tris-Ccyanoethyl] Phosphine Oxide / Benzyl Nopenylene Phosphonate Combination as Flame Retardant in Polyphenylene Ether.

5 Example Phosphine Oxide Phosphonate Flame Power Score

XXII 4% A - FB

XXIII --- 4% B FB

XXIV 2% A 2% B V-0 XXV 1% A 3% B V-1 10 XXVI 3% A 1¾ B V-1

While 4% by weight of each compound is only free-burning (inactive), combinations of the two compounds in ratios of 1: 3, 2: 2 and 3: 1 at a total concentration of 4% are effective flame retardants,

15 Examples XXVII - LIV

According to the procedure of Examples XXII-XXVI, combinations of phosphine oxides and phosphonates as flame retardants were evaluated. The following compounds were tested: A. tris-C2-cyanoethyl) phosphine oxide 20 B. benzyl neopentylene phosphonate C. phenyl neopentylene phosphonate

□. Cp-phenylenedimethylene} bis- / "2,2-dimethyltrimethylene phosphonate"

E. C2.5-dimethyl 1-1.4-phenylene dimethylene] bis ^ 2,2-dimethyl trimethylene phosphonate ^ F. 2,4,6-trimethylbenzyl neopentylene phosphonate G. tris- (benzyl] phosphine oxide H. triphenylphosphine oxide I. tris-Cp-chlorophenyl] phosphine oxide 30 J. tris- (n-actyl] phosphine oxide K, benzyl bis- (cyclohexyl] phosphine oxide L. bis - / "(dicyclahexylphosphinyl] methyl. 7-terephthalate II. Ethylene bis-" bis- (2-cyanoethyl) phosphine oxide. ] phosphine oxide, 8004920

- 14 -Table B

Example Phosphine Oxide Phosphonate Flame Power Score

XXVII - 4% C FB

XXVIII 2% A 2% C V-1

5 XXIX --- 6% D FB

XXX 2% A 2% D V-1

XXXI --- 4% E FB

XXXII 2% A 2% E V-1 XXXIII --- 4% F V-1 x

10 XXXIV 2¾ A 2% F V-0 XX

XXXV 4% G - FB

XXXVI 2% G 2% B V-1

XXXVII 4% H --- FB

XXXVIII - 2% H 2% B V-1

15 'XXXIX 4% I - FB

XL 2% I 2% B V-1 XLI 4% J --- FB 'XLII 2% J 2¾ B V-1

XLIII 4% K --- FB

20 XLIV 2% K 2% B V-0

XLV 4% L - FB

XLVI 2% L 2% B V-1

XLVII 4¾ M - FB

XLVIII 2% M 2% B V-2

25 XLIX 4% N - FB

L 2% N 2% B V-1

LI - 4% C FB

Lil 2% G 2% C V-1 LUI 4% 0 - FB / V-1 30 LIV 2% 0 2% C V-1 / V-0 x mean time to extinction - 15 sec XX mean time to extinction - 3 sec ff, * '

The data demonstrate that while individual phosphine oxides 35 or phosphanates of the invention are not active flame retardants 8004920-15 for polyphenylene ether resins at a concentration of about 4%, the combinations of Option 5 at the same concentration are effective flame retardants.

8004920

Claims (9)

A flame retardant composition comprising a homogeneous mixture of polymers containing about 10 - 90 parts by weight of polyphenylene ether resin, about 90 - 10 parts by weight of polystyrene, and an effective flame retardant amount of a compound selected from 5 CR) 3PO (13 wherein R represents alkyl of 1-6 carbon atoms, haloalkyl of 1-6 carbon atoms, halophenyl of 1-3 halogen atoms, benzyl, alkylbenzyl of 1-3 alkyl substituents each having 1-4 carbon atoms, or cycloalkyl of 5-8 carbon atoms; 10 0 1 "2 CR 3" -PR (23 1 ^ where R is selected from alkyl of 1-4 carbon atoms, cycloalkyl of 5-8 carbon atoms, carboxyalkyl wherein alkyl has 1-4 carbon atoms, phenyl, halophenyl of 1 -3 halogen atoms, alkoxyphenyl wherein alkoxy has 1-4 carbon atoms; R is selected from hydrogen, alkyl of 1-12 carbon atoms, cyanoalkyl wherein alkyl has 1-4 carbon atoms, benzyl, alkylbenzyl of 1-4 carbon atoms 5 alkyl substituents each containing 1 to 4 carbon atoms and hydroxyalkyl of 1-4 carbon atoms, with the proviso that when R is carboxyalkyl, R does not represent hydrogen or benzyl; 0 0 CNCCH2CH232-PYP- (CH2CH2CN} 2 (33 where Y is selected from 25 (13 alkylene of 1-4 carbon atoms; (23 substituted xylylene of formula 5, wherein each X represents a halogen atom or an alkyl group of 1-4 carbon atoms and m is an integer from 1 to 4, with the proviso that when none are X halogen, the methyl groups are meta-toothed relative to each other; 3 (33 is the group of formula 6, wherein R is alkyl of 1-4 carbon atoms p represents an integer of at least 1 8004920-IIIs and q equals O af 4-p; C4Ï the group of formula 7; or C5Ï the group of formula 8; 0 0 5 (R ^ PQ-PCRΊ2 C4) 4 wherein R is selected from cycloalkyl of 5-8 carbon atoms, phenyl, carbamoylethyl and carboalkoxyethyl, wherein the alkoxy group has 1-4 carbon atoms, and wherein 5 is selected from alkylene 5 having 1 - S carbon atoms, the group of formula 9 wherein R is alkyl 10 with 1-4 carbon atoms and n represent an integer of 1-4, or the group m et formula 10 with the proviso that when R is carboalkoxyethyl and Q represents the group of formula 9, n equals 4; and as a fifth possibility a combination of C 1) phosphine oxide of formula 1, wherein R and R are each selected from alkyl of 4-12 carbon atoms, cycloalkyl of 5-8 carbon atoms, phenyl, halophenyl of 1-3 halogen atoms, Ü-cyanoalkyl wherein alkyl has 1-4 carbon atoms, and benzyl; or a phosphine oxide of formula 4 4, wherein R is selected from cycloalkyl of 5-8 carbon atoms or 20 W-cyanoalkyl wherein alkyl contains 1 to 4 carbon atoms, and X is selected from - (CHn 3 -, where n is an integer 1 - 6; formula 9 is 5 n wherein R alkyl has from 1 to 4 carbon atoms and n represents an integer from 0-4; or the group of formula 10; and CiiJ is a phosphonate g compound selected from formula 11, wherein R is selected from phenyl, benzyl or alkylbenzyl, having 1-3 alkyl groups each having 1-4 carbon atoms, and formula 12, wherein Z represents the group of formula 23, wherein R 1 alkyl having 1 to 4 carbon atoms and x is an integer of 0- 4 which mixture contains the components C 1 and C 3 in a weight ratio of about 1: 3 to 3: 1. The composition according to claim 1, characterized in that the mixture contains about 50-80 parts by weight of polyphenylene ether resin and about 20-50 parts by weight of polystyrene. The composition according to claim 1, characterized in that R 35 is selected from the group consisting essentially of n-propyl, 8004920-18-n-butyl, cyclohexyl, chloromethyl, phenyl, p-chlorobenzyl, and 2.4. 6-trimethylbenzy1. A composition according to claim 1, characterized in that R 1 is cyclohexyl and R represents benzyl or hydroxymethyl. Composition according to claim 1, characterized in that R 2 is carboxyethyl and R represents methyl. The composition according to claim 1, characterized in that Y is selected from the group consisting essentially of -CCh ^ ^ and formulas 24-28. Composition according to claim 1, characterized in that X represents 4 and R is selected from phenyl, carbamoylethyl, and cyclohexyl. Composition according to claim 1, characterized in that the combination according to the fifth possibility is a mixture of a phosphine oxide 15, selected from the group consisting essentially of tris- (2-cyanoethyl-13-phosphine oxide, tris- (benzyl) phosphine oxide, triphenylphosphine oxide, tris (p-chlorophenyl) phosphine oxide, tris (n-octyl) phosphine oxide, benzyl bis-cyclohexylphosphine oxide, bis-Z * Cicyclohexyl-bis-methyl-7-terephthalethyl-7-terephthalethyl-7-terephthalethyl, (2-cyano-20-ethyl} -phosphine oxide_7, C2,3.5,6-tetramethyl-1,4-phenylenedimethylene-3-bis-£-bis-C2-cyanoethyl-3-phosphine oxide-7, and benzyl-bis- (2-cyna-ethyl-3-phosphine oxide and a phosphonate selected from the group consisting essentially of benzyl neopentylene phosphonate, phenyl neopentylene phosphonate, Cp-phenylenedimethylene3-bis-T2,2-dimethyltrimethylene-25-phosphonate-7,2,5-dimethyl-1,4-phenylene-dimethylene-3-bis-2,2-dimethyl-trimethylene. 6-trimethylbenzylneopentylene phosphonate. An article of manufacture made using a flame-retardant composition according to any of claims 1 to 8. 8004920