NL7907579A - FLAME RETARDANT ON THE BASIS OF A POLYPHENYLENE ETHER RESIN. - Google Patents

Description

m ·. i VO 8339

American Cyanamid Company,

Wayne, Hew Jersey, United States of America.

Flame retardant based on a polyphenylene ether resin.

The invention relates to a "flame retardant based on a polyphenylene ether resin," containing an effective flame retardant amount of a phosphine oxide containing at least two 2-cyanoethyl groups (-CHgCS (Cl)). More specifically, "the invention relates to" flame retardant thermoplastic resin, "containing a compound of the formula T of the formula sheet, wherein S is an alkyl group having about 1-12 carbon atoms, a hydroxyalkyi group, wherein the alkyl portion is about 1 -8 carbon atoms, a benzyl group, alkylbenzyl group, in which the benzyl ring contains at least two 10 alkyl groups with about 1-1 carbon atoms, and a w-alkyl group, in which the alkyl group contains about 1-1 carbon atoms, proposes.

Particularly advantageous compounds of the foregoing are 1) tris (2-cyanoethyl) phosphine oxide, 2) benzyl bis (2-cyanoethyl phosphine oxide and 3) 2,1,6,6-trimethyl benzyl bis (2 cyanoethyl) phosphine. oxide with resp. formulas 2, 3 and U of the formula sheet.

Tris (2-cyanoethyl) phosphine oxide is a known compound and is described by Rauhut et al, J.Am.Chem.Soc., Vol. 8, p.

1106 (1959). The compound has been used as a flame retardant for thermoplastic vinyl polymers including polypropylene, as described in U.S. Pat. No. 3,3-1,625. The benzyl bis (2-cyanoethyl) phosphine oxide and the 2,1 ', 6-trimethylhenzyl-his (2-cyanoethyl) phosphine oxide can be prepared by reacting benzyl chloride or 2,1', 6-trimethylbenzyl chloride with bis (2-cyanoethyl 1-25 phosphine oxide. Compounds wherein R represents alkyl group or hydroxyalkyl group are prepared in a corresponding manner.

Flame retardant, rubber-modified polyphenylaenether resin blends are prepared by incorporating an effective flame-retardant amount of a compound of the above formula.

The polyphenylene ether resin blends, suitable for use with the 790 75 79 ¢. -....... _: _. 2.

The present methods are described in U.S. Patent No. 1, 02, .093, the contents of which are incorporated by reference herein. In principle, these resin blends contain about 10-90 parts by weight. polyphenylene ether and about 90-10 parts by weight. of a styrene polymer. Preferably, the polymer contains about 50-80 parts by weight. polyphenylene ether resin and about 20-50 parts by weight. styrene polymer »The styrene polymer can be a rubber-modified polystyrene with high impact strength. The resins are mixtures of the two polymers, which are mutually soluble and form a homogeneous polymer mixture.

The flame retardant compounds are used in an amount sufficient to obtain a self-extinguishing material as defined below. Generally, however, the amount is at least about 1% by weight based on the weight of the resin mixture, preferably at least about 6%, and more particularly about 8-10%.

It is also within the scope of the invention to include such additives such as plasticizers, dyes, pigments, heat and light stabilizers, antioxidants, antistatic agents, photochronic materials, and the like.

Example I

The preparation of benzyl bis (2-cyanoethyilphosphine oxide) was carried out as follows:

O

78 g (0.5 mol) of bis (cyano-)

Ethyl) phosphine oxide. A solution of 33 g (0.5 mol

3 .......

potassium hydroxide x 200 ml of methanol was then added. 63 g (0.5 mol), benzyl chloride, were added dropwise to this solution. The mixture was refluxed for 2 hours, then the methanol was distilled off. Reflux was continued for 30 minutes and then cooled. The potassium chloride was filtered off and the dimethylformamide was removed by distillation using a film evaporator. , o ''

The resx was extracted three times with 300 cm of boiling toluene.

The combined toluene extracts were cooled to give a yield of 50 g of a white crystal all-solid with a melting point of 7907579 ψ -1 * '' 3 van 1-18-120 ° C.

Example II

In accordance with Example 1, however, using 2, h, 6-trimethylbenzyl chloride instead of benzyl chloride, the corresponding compound was obtained.

Example III

Preparation of 1,1-dimethylhydroxymethylhis (2-cyanoethyl) -phosphine oxide (Jr. Chem. 25, H62Q-2632 (19.61).

0.1 g of triethylamine or pentamethylguanidine was added to a mixture of 0.1 mol bis (2-cyanoethyl) phosphine oxide and 0.1 mol acetone.

added. The mixture was refluxed for 2 hours on a. steam bath temperature boiled. The solid obtained was filtered off and recrystallized from acetone to give the product in a yield of 88/5 with a melting point of 12l + -125 ° C. Example IV

To a mixture of 50 parts of polyphenylene ether / 50 parts of high impact rubber-modified polystyrene, a sufficient amount of the tris (2-cyanoethyl) phosphine oxide (TCEP0) omi> i was added. make 10 g samples as shown in Table A.

* It was mixed dry and extruded through a melt indexer (described in ASM D-1238) at 290-300 ° C. The cylindrical extrudate, length 7-5-12.5 cm and diameter 0.6 cm, was subjected to the following flame test, described in Underwriters Laboratories Test UL-9, Vertical Test Method 3.10-3.15 (September 1973). The polymer test sample, fixed in a vertical position, was lit with a blue flame (methane or natural gas) of 3A for 10 seconds, after which the flame was removed. When the flame died out within 2b seconds, the sample was again ignited for 10 seconds and the flame removed again. Then the quenching time of the flame 30 was observed again. When the flame extinction time was not greater than 5 seconds for each flame application, the sample was rated at V-0; when the flame extinction time for either the first or second flame application was 5-25 seconds, the sample was rated at V-1. When a sample exhibited a quenching time of more than 25 seconds for each flame application, it was designated as free-burning (FB) and was considered insufficient for the 7907579, fc test.

TABLE · A

% TCEPO Flammability rating a

no. EB; PB

5 6% PB; FB

8I V-1; V-1

• s two determinations Example V

The procedure of Example IV was repeated, except that a mixture of T0 parts of polyphenylene oxide and 30 parts of rubber-modified polystyrene was used. The results of. both the UL-9 ^ test and the oxygen index test are shown in Table B.

TABLE · B, 15 Sample Burn Time Flammability— Oxygen Index Seconds. rating __

control, PB 18, T

2% TCEPO, PB 19.8 b% "9.25. V-1 21.3 2Q 6%" 3.25 V-1 23.2 8% "10.0 V-1 23.9

Example VI

The procedure of Example V was repeated, except that the material was processed at 280 ° C and only the oxygen index of each sample was determined. The results were Sample Oxygen Index Control 18.5 2% TCEPO - 20.1 kfe "20.7 30 6%" 22.3 8% ”22.8 W%” 23.2

Example VII

The method of. Example IV was repeated, except as y. . It was noted that the benzyl bis (2-cyanoethyl) phosphine oxide (BBCEPO) was used instead of the tris (2-cy anoethyl) phosphine oxide. The results of both the UL-91 and most acidic or index tests are shown in Table C.

TABLE C

5 Sample Burn time flammability oxygen index seconds rating_ control, - EB 18.7 k% BBDEPO 25, - PB 22.8 6% f 10, 15 V-1 25.7 10 8% ”, 3 V-0 26, 3

Example VIII

According to the procedure of Example IV, 6 wt.% Of the following components were determined to provide self-extinguishing polymer mixtures, ie, either V-0 or V-1: compound of formula 3 compound of formula n-CgE 2 -PO ( CH ^ CH ^ CEr) ^ compound of formula 5, compound of formula 6, compound of formula k and 20 the compound of formula C (0H) (CK3) PO (Cff2CH2CIT) 2

Comparative example

According to the method of Example IV, the flammability of high impact polystyrene was determined, which was 20%. % TCEPO contained. The samples were 2 ^ free-burning (EB) in a determination according to the UL-9 test.

The above examples illustrate that (1) for a 70/30 blend of polyphenylene oxide, the TCEPO has a critical concentration of about h wt% to provide self-extinguishing properties (2) for a 50/50 blend about 6 wt% required for each flame retardant; (3) TCEPO is not a flame retardant even at a concentration of 20%. %, for high impact polystyrene.

790 7 5 79

Claims (7)

2. Material according to claim 1, characterized in that the mixture is about 50-80 parts. polyphenylene ether resin and. " 5Q-2Q parts' contains polystyrene. 3. Material according to claim 1, characterized in that the flame-retardant compound is tri (2-cyanoethyl Ifphosphine oxide). 1+ Material according to claim 3, characterized in that the mixture about 10 parts of polyphenylene ether and about 30 parts of polystyrene and the phosphine oxide is included in an amount of at least 20% by weight based on the mixture of the polymers. Material according to claim 3, characterized in that the mixture contains about 50 parts of polyphenylene ether and about 50 parts of polystyrene and the phosphine oxide is included in an amount of at least 6% based on the mixture of the polymers. Material according to claim 1, characterized in that the flame-retardant compound is 2,4,6-trimethylbenzylbls (2-cyanoethyl-1-phosphine oxide). Compound according to claim 6, characterized in that the phosphine oxide is included in an amount of at least about 30% by weight based on the mixture of the polymers. 8. The material according to claim 1, characterized in that the phosphine oxide is included in an amount of at least about 6% by weight based on the mixture of the polymers. 9. Material according to claim 1, characterized in that the phosphine oxide is included in an amount of about 8-10. based on the mixture, based on the mixture, ram the polymers. The material according to claim 1, characterized in that the group R is selected from benzyl, pentamethylbenzyl; 2,5-dimethylbenzyl, n-octyl and 1,1-dimethylhydroxymethyl. 790 75 79> 'ί. 1.o r-p4ch2ch2cn) 2 (ncch2ch2) -3p 0-3 ^ ~ ^ ch2-p {ch2ch2cn) 2k CH / J o CH3 \ _CH2-J- (CH2CH2CN) 2 Vx CE3 CH- CH- 5 \ / o ------------- chJH- 11 LHr ~ \ _ / - ch2- P 4 ch2ch2cn) 2 ch3 \ h3 6 ^ o γ ___ ν — ch2 — P 4 ch2ch2cn) 2 ch3 790 75 79