CA1136307A - Polymer compositions - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Flame retardant polymer compositions comprise a polymer of styrene or another vinyl aromatic monomer, or a copolymer of styrene with another monomer or a polymer blend of a styrene polymer with another polymer, such as a polyphenylene oxide, and a triaryl phosphate of the formula:

Description

~3~3~7 The present invention relates to flame retardant compositions containing significant amounts of a thermoplastic polymer from a vinyl aromatic monomer, such as styrene, and co-polymers and polyblends containing a polymer from a vinyl aromatic monomer.
A polymer composition containing polystyrene and an aromatic polyether, for example polystyrene and poly phenylene oxids is flammable and where resistance to burning is required the polymers are traditionally made flame retardant by adding flame retardants containing phosphorus, halogen, antimony or any combination of these. The triaryl phosphate, tri-phenyl phosphate has been described as a flame retardant for these polymer compositions, However, when this compound is present in amounts necessary for flame retardance a substantial decrease in heat distortion temperature occurs, Also, triphen~ phosphate is too volatile and evaporates from the composition during processing of the polymer, when high processing temperatures are used, i.e. above 200C. Thus, an initial excess of triphenyl phosphate has to be incorporated into tha polymer composition in order to allow for this loss on processing.- Tri-mesityl phosphate has also been described as a flame retardant for polystyrene/poly phenylene oxide compositions in United Sta-tes Patent Speci~ication No. 388361'.
This phosphate does not cause a marked reduction in the heat distortion temperature, but its flame retardant ~3~ 7 properties are insufficient.
There is, thexefore, a need for an additive which gives good flame retardance, but has less effect on the heat distortion temperature of the polymer than does tri-phenyl phosphate.
Surprisingly, we have ound that certain triaryl phos-phates combine the properties of acceptable heat distor-tion temperature with suficient flame retardance and have lower volatility than triphenyl phosphate.
Accordingly, the present invention provides composi-tions comprising:
(i) a polymer of styrene or other vinyl aromatic mono-mer, or a copolymer selected from the group consisting of styrene/a-methyl styrene, styrene/acrylonitrile, styrene acrylates, acrylonitrile/butadiene/styrene, styrene/buta-diene (high impact polystyrene), styrene/ethylene , styre-ne/propylene and styrene/butylene, or a polymer blend selected from the group consisting of polystyrene/poly-vinyl chloride, styrene/nitrile rubber, styrene/isopropene ~ubber, polystyrene/polyphenylene oxide and styrene-buta-diene co-polymers/polyphenyleneoxide, and (ii) from 1 to 100 parts by weight per 100 parts of polymer of a triaryl phosphate of the formula ~ CH3 )3-x ~ ~ 2 x where x is 0, 1 or 2 and Rl, R2 and R3 are the same or different and represent hydrogen or an a:Lkyl group having 1 to 9 carbon atoms.

:
.

,.
.

31~30r~

Rl, R2 and R3 can occupy any positions on the ring, but the 21 4 and 6 positions are preferred.

Non-limiting examples of the triaryl phosphakes are tris (2,6-dimethyl phenyl) phosphate bis ~2,6-dimethyl phenyl) phenyl phosphate mono (2,6-dimethyl phenyl) dlphenyl phosphate bis (2,6~dimethyl phenyl) 4-t-butyl phenyl phosphate bi 3 (2,6-dimethyl phenyl) 4-methyl phenyl phosphate bis (2,6-dimethyl phenyl) 3-methyl phenyl phosphate bis (2,6-dimethyl phenyl) 4-isopropyl phenyl phosphate bis (2,6-dimethyl phenyl) 2-isopropyl phenyl phosphate In ~ormula I Rl, R2, R3 are preferably hydrogen or ; Cl - C4 alkyl, more preferably hydrogen or methyl and most preerably hydrogen.

Non-limiting examples of the vinyl aromatic polymers ara polystyrene, poly a-methyl styrene, polyvinyl toluene polychlorostyrene.

Preferred are polymer blends of polyphenylene oxide and polystyrene or a co-polymer of styrene and butadiene, the polyphenylene oxide being described by the general ~ormula:

: ~ :

::

,. . .
! ' . ' , ' ~:, . I

~3~;3~?~

~ 4\~_./ 5 \o\-~ ~

n wherein R4, R5, R6 and R7 may be the same or different, : and ea~h is a hydrogen or haloyen atom, or a hydro-aarbon, sub~tituted hydrocarbon, cyano, alkoxy, phenoxy, : amino, .qulpho or n~tro group and n is a whole number o at least 50. For example, R4, R5, R6 and R7 may be hydrog~n, chlorlne, bromine or a methyl, ethyl, propyl, ~ allyl, phenyl, benzyl, methyl benzyl, cyanoethyl, - cyano, methoxy, ethoxy, phenoxy or nitro group.

~pecific non-limiting examples o such polyphenylene ~xides include poly 2,6-dimethyl-1,4-phenylene oxide, '~ poly-~,6-diethyl-1,4-phenylene oxlde, poly-2,6-dipropyl-`~ 1,4-phenylene oxide, poly-2,6-dimethoxy-1,4~phenylene oXide, poly-2,6-dimethoxy-1,4-phenylene oxide, poly 2,6-dichloro-l,4-phenylene oXide.

'~

:

: .~

..
~-.

- ~3~3~

The preferred polyphenylene oxide is poly-2,6-di-methyl-1,4-phenylene oxide. The preferred poly-blend is high impact polystyrene and poly 2,6-di-methyl-1,4-phenylene oxide, e.g. those sold und~r the 'rrademark ~ oryl.

The amounts of triaryl phosphate per hundred parts o polymer preferably employed are ~rom 2 to 35 parts and most preerably ~rom 5 ko 25 parts by weight. ~he amounts o~ phosphate used will vary depending on the type of polymer, the properties required and the amount and type of other ingredients which may be present.

The composikions of the invention may also contain an oligomer of the general formula II
, a ( H2 )b[ CH2(0CH2)moCH2-]C(-CH2X)d II
';~
. wherein A is at least one aromatic hydrocarbon or heterocyclic residuel X is a leaving group, a is 2 to 20 but equals b ~ c + 1, b ls 0 to 19, c is 0 to 19, ~: d is 0 to 2a and m is 0 to 10, preferably 0 to 5, most ~: preferably 0, there being at least two (-CH2X) groups per molecule, the group (-CH20CH2-) counting as t-CH2X) ~: for this purpose when m = 0, and the group (-CH20) : counting as a (-CH2X) group when m ~ 1.

:

~`

~ ~-3 ~ :'7 ~. ' ' ' . : '' :" ' ' ' '`' ' ' ' ~ ' '. ' , .

1~3~i3~7 It should be noted that the~ ~alues of a, b, c, d and n are average values for the average molecule of formula II.

Leaving group X i~ formula II is halogen, -OH, -SH, -NH2, -C02H, -P03H2, OB~OH)2 and their derivati~es, for example -ORl, -SRl, _NHRl NRlR2 OB( 1)( 2 Non-limiting examples o~ such deri~atives and other X group~ may be represented by the general ~ormulae W L y2R2 M
.. . . .
w~ere Y~ ~ and ~ are, independently, O-~ -NH-, -N-, -S~, or R
are absent, but preferably are -O- or -S-1 Rl SRi NH NHR~ R2 or a direct bond.link~n~ C back to R or to a CH2 attac~ed to R

but prafar~bly i.s H or R ;
W is O~ S~ ~ or NRl9 but pre~erably is O or S;
L is O~ S or is absent~ but preferably is O;
M is O or is abso~t, but prc~orably is O;

.~.. ,., .. ,~__, . ;_ _ ____ ,.. _ _.... ___. .... ___ _ .. ~ .__.. .... _., .. _......... . . .

.

1J~3~i3~

~nd whcr~in Rl represents a straicht or branched chain al~yl ha~ing 1 to 12 carbon atoms, preferably 1 to 4, ~ut most preferably 1, alkenyl or allc~nyl having 2 to 12 carbon ~to~s, preferably 2 to 4, cycloalkyl or cycloalkenyl havin~
5 to 12, preferably 6 carbon at;oms, aralkyl, aralkenyl or aIkaryl i-aving 7 to 12 carbon atoms, preferably benzyl or .. ... . ..
naphthyl methyl or aryl having 6 to 15, preferably 6 to 12 carbon atoms~ most preferably be~zyl or napht~yl methyl.
R may be optionally substituted by one or more halo~en, hydroxy, epoxy, nitrile, amine, amidey ether, carboxyl or ester ~roups or combin~tions thereof~ but is pre~erably unsubstituted. R2 has the same significance as Rl and may be the same or di~ferent. The lea~in~ group may also be a salt o~ an acidic or basic X ~roup.
Howe~er, o~ the non-limitin~ examp~es, compounds of ~ormula I where X 3 OX or a derivative of this group are preferred.

Examples of aromatic residues A are benzene 7 naphthalene, furan9 anthracsne, biphenyl and diphenyl ether. The aromatic residue A may be unsubstituted or substituted by one or two substituents. It is preferably unsubstituted, but if it is substituted it preferably carries only one substituent. Suitable substituents include halogen, alkyl groups with 1 to 4 carbon atoms, haloalXyl groups with 2 to 4 carbon atoms, ' .

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

~.

' ` 1~3~3~
g and the group oR3 where R3 i9 hydrogen, alkyl with 1 to 4 carbon atoms or acyl with 1 to 4 carbon atoms.
The compounds represented by ~ormula II are mixtures of oligomers with a range o~ molecular weights. The residues A are linked by (-CH~-) or ~-CH2(0CH2)mOCH2-]
groups, these two linking groups being connected only to a residue A and not to each other. The groups (-CH2X) are connected to a residue A.
Pre~erably greater than 50 mol ~0 of residue,s A are deri~ed from naphthalene; most pre~erably more than '~
75 mol ~ of residues A are derived from naphthalene.
Oligomers which are preferred are those having a number average weight of 300 to 3500, more preferably thoqe having a number average molecula~ weight of 350 - 1500, most preferably 400 to lOOQ. It is preferred that the naphthalene residues are linked by (-CH20CH2-) and that these links should be attached to t~e positions 1,4;
1,5; 1,6; 1,7; 2,5; 2,6 or 2,7 on the naphthalene residue.
It is most preferred that the links should be attached to the 1,4 or 1,5 positions on the naphthalene residue.
No,n-limiting examples o~ particular oligomers of structure II are those linked by the group -C~20CH2-and having two or more -CH2X groups per molecule.
Preferred structures which can be pr~sent as a component of the oligomer mixture are shown below. The group -CH20~H2- being counted as a -CE2X group.

.

113~

r~ o c~ e~
~J
, u2, o c ~c~ c~ c~ c~

(~CH~)~ ~7 I ca~x Where m = O or 1~ and X = OH
O
Il -O~H2 ~ or -O ~

Specific Examples of oligomers of formula II abo~e are listed in Table A.

.. , .. ~

" ~3~3~7 _ ~ o ~ ~ ~ X
"
a e o o o o ~ o . , ~
o ~
~1 00 ~~ 00 0 . . .. . .
~I o oo o o ~U O ~
~ ~ o ~ U~ ~
O
_ ~ ~ ~ ~, o U~ O ;t ~O CU ~ ~
~ ~ O O O O ~i 0 ~ ~
~, ~ _ ~ ~ ~
~1 u~ C~ ~ N ~ 1 ~ o I t3 1~ ~ ~ CO ~oo t~ c~l c~ t ~ h h . . _ ,~ ,6D
~:: ~ h o o ~1 ~ ~ ~, o ~ ~ ~ o o O h o ~ ~ l ~ ~
rl O ~-rl ~ ~) ~
O ~ O ~ ~ ~ ~ ~ ~
13 h h P:; ~ o O ~ h p~ P ~ ~ ;3 h ~ O O
h . ~ ,~
_ . , __ o a~ a~
h o o ~ ,q o ~ o o o ~o~u~ ~I C`l ~ ~ ~ oo rl~ri ~ ~ U~
o a~
X ~

The addition o~ ~uch aD. oligom~r is e3pecially usef`ul in thinner section s~eets, e.g. 1,5 mm. pro~idi.ng polymer sheets which do not drip when burnt in the manner described in the following Examples.
The compositions of the~ in~ention may also contain a novolak in addition to or instead of the oligomer.
No~olaks used in accordance with the pr~sent i~vantion may be any no~olak prepared by known methods from an aldehyde and a phenolO Usually the molar ratio of phenol:aldehyde i~ lsO.9 or less and the reaction may be ef~ected under acid or alkaline conditions. Suitable phenols incluae phenol itself, resorcinol, alXyl-substituted phenols, such as cresols, xylenols and tertiary butyl phenols, aryl substituted phenols, especially p-phenylphenol, and halophenols.
The aldehyde which i5 condensed with the phenol i5 preferably formaldehyde, but other aldehydes such as acetaldehyde and furfuraldehyde may also be used.
Pre~erably, the novolaks haYe the general formula oR' oRI ~R~

~l ~ C

(~)~ (R)h,, . ( R)~, and may be the same or different, where m represents ~ero, l, 2, or 3.
the groups R, which may be the same or different, each represen1;s an alkyl group especially of 1 to 4 carbon atom , ~ aryl ~roup, e~pecially a phenyl group, a halogen . : i i . ... . . .

:

atom, especially a chlorine atom, or a hydro~y group, The Rl group~ each represent hydrogs~, an alkyl group o~ l to 4 carbon atoms or a glycidyl group.
n represents a number o~ a~erage ~alua 1 to 12, and the methylene linkage~ are ortho and/or para to the OR groups.
Particularly preferred are no~olaXs of formula I in ~hich m represents zero, those in which m represents 1 or 2 and R represent~s an alkyl group of 1 to 4 carbon atoms, a phenyl grOllp~ or a chlorine atom and Rl represents hydrogen.
Also preferred are novolaks of formula I in which n has an average ~alue of from 1 to 5.
It i~ ~ell Xnown that unless special purification procedures are adopted, novolaXs Are comple~ mixtures of products of various molecular weights, and some components cannot ~e separated from other components on a preparati~e scale. For this reason n is defined in terms of its average value. In any particular product, howe~er, the average ~alue is made up of a range of ~alu~s. A~ average value o~ n as 4, for example, has been shown to be made up o~ species in ~hich n has the value from 1 to 11.
When an oligomer or ~oYolak is present with the phosphate, the weight ratio of phosphate to oligomer or no~olaX may be from 1:5 to 50:1. Preferably the ratio is from 1:1 to 25:1 and more preferably from 3:1 to 15:1.
Examples of other ingredients which may be present in the composi~ions of the in~ention are:
heat ~tabil:i~er~9 light ~tabilisers, W absorbers, antioxidants, filler~, pigment~, lubricants9 additi~es to improve mold relea~e, fungicides, , ~3ti3~

blowing agents, optical brightening agents, other fire retardant additives or other processing aids. Suitable antioxidants include the sterically hindered phenol compounds for example: 2,2'-thio-bis-(4-methyl-6-tert. butylphenol), 4,4'-thic)-bis-(3-methyl-6-tert.butyl-phenol), 2,2'-methylene-bis(4-methyl-6-tert. butylphenol), 2,2'-bls-~4,4'-phenylol) propane, 2,2'-methylene-bls-(4-ethyl-6-tert.butyl-! phenol), 9,4'-methylene-bis-(2-methyl-6-tert.butyl-phenol), 4,4'-butyl-idene-bis-~3-methyl-6-tert.butylphenol), 2,2'-methylene-bist4-methyl-6-(a-methyl-cyclohexyl)-phenol], 2,6-di(2-hydroxy-3-tert.butyl-5-methylbenæyl) 4-methyl-phenol, 2,6-di-tert.butyl-4-methylphenol, 1,1,3-tris-(2-methyl-4-hydroxy-5-tert.butyl-phenyl)-butane, 1,3,5-trimethyl-2,4,6-tri(3,5-di-tert.butyl-4-hydroxy-benzyl)-benzene, esters of ~-4-hydroxy-3,5-di-tert.bu-tylphsnyl-propionic acid with monohydric or polyhydric alcohols, such as methanol, ethanol, octadecanol, hexanediol, nonanediol, thiodiethylene glycol, trimethyl-olethane or pentaerythritol, 2,4-bis-octylmercapto-6-(4-hydroxy-3,5-di-tert.butylanilino)-s-triaæine, 2,4-bis-(4-hydroxy-3,5-di-tert.butyl-phenoxy)6-octylmercapto-s-triazine, 1,1-bis(4~hydroxy-2-methyl-5-tert.
butyl phenyl)-3-dodecyl-mercapto~butane, 2,6-di-t-butyl-p-cresol,

2,2-methylene-bis(4-methyl-6-t-butylphenol),4-hydroxy-3,5-di-tert.butylbenzyl-phosphonic acid esters, such as the dimethyl, diethyl or dioctadecyl ester, (3-methyl-4-hydroxy-5-tert.butyl benzyl)-malonic acid dioctadecyl ester, s-(3,5-dimethyl-4-hydroxy-phenyl)-thioglycollic acid octadecyl es-ter, and es-ters r~

- : ~: '. ' " ' -~lL13~3~7 oE bis-(3,5-di-tert.butyl-4-hydroxyben~.yl)-malonic acid, such as the didodecyl ester, the dioctadecyl ester and 2-dodecyl-mercaptoethyl ester.

Suitable llght s-tabilisers and uv ab.sorbers include: sterically hindered cyclic amines of the formula '--\C/
I
~ Y

--~C~ q and salts thereof in which q is 1 or 2, X represents an organic grouping which complements the nitrogen-containing ring to give a 5-membered, 6-membered or 7-membered ring, Rl and R2 represent methyl or together represent -~CH2)5-, R3 represents methyl, Rq represents alkyl with 1 - 5 carbon atoms or together with R3 represents the 2 4 ~ (CH2)5 , -c~l2-c(cH3)2-NH-c(cH ) -CH - or -CH2-C(CE13)2-N(o )-C(CH3)2-CH2- and, iE q is 1, Y denotes hydrogen, -0 , hydroxyl, alkyl, substituted alkyl, alkenyl, aIkynyI, araIkyI, substituted arlalkyl or acyl or, if q ", . j, ! ~ ., '~! ~ . .

3~i ;3~7 is 2, Y denotes alkylene, alkeny].ene, alkynylene, cycloalkylene or aralkylene.

Examples of sterically hinderecl cyclic aMines o~ formula I
are 4-benzoyloxy-, 2,2,6,6-tetramethy].piperldine; 4-capryl-oyloxy-,2,2,6,6-tetramethylp~eridine; 4-stearoyloxy-,2,2,6,6-tetra-methylpiperidine; bis-(2,2,6,6-tetrame-thyl-4-plperidyl)-~ebacate~ bis-(2,2,6,6~tetramethyl-4-piperidyl)-dodecanediote and bis-(1,2,2,6,6-pentamethyl-4-piperidyl)-sebacate.

2-(2'-Hydroxyphenyl)-benætriazoles, such as for example, the 5'-methyl-, 3',5'-di-ter~.butyl-, 5'-tert.butyl-, 5'-~1,1,3,3-tetra-methylbutyl)-, 5-chloro-3',5'-di tert.butyl-, 5-chloro-3'-tert.butyl-5'-methyl-, 3'sec.butyl-5'-tert.butyl-, 3'-~-methylbenzyl-S'-methyl-, 3'-~-methylbenz.yl-5'-methyl-5-chloro-, 4'-hydroxy-, q'-methoxy-,

4'-octoxy-, 3',5'-di-tert.amyl-, 3'-methyl-5'-carbomethoxyethyl- and

5-chloro-3',5'-di-tsrtO-amyl-derivative.

2,4-Bis-(2' hydroxyphenyl)-6-alkyl-s-triazines such as ~or example, the 6-ethyl-, 6-heptadecyl- or 6-undecyl-derivative.

2-Hydroxy-benzophenones, such as for example, the 4-hydroxy-, 4-methoxy-, 4-octoxy-, 4-decyloxy, 4-dodecyloxY-, 4-benzyloxy-, 4,2',4'-trihydroxy- or 2'-hydroxy-4,4'-dimethoxy-derivative.
, ~
l~3-Bis-(2~-hydroxybenzoyl)-benzenes such as,~or example, ;~ I,3-bis-(2'-hydroxy-4'-hexyloxy-benzoyl)-benzene, 1,3-bis-(2'-hydroxy-4'-octyloxy-benzoyll-benzene and 1,3-bis-(2'-hydroxy-4'-dodecyloxy-benzoyl)-benzene.
'X

- . . .. . .

. ::::: . : :
.. :

~3i~

Esters of op-tionally subs-titutecl ben~oic acids, such as, for example, phenyl salicylate, octylphenyl salicylate, diben~oylresorcinol, bis-(4-tert.-butylbenzoyl)-resorcinol, benzoylresorcinol and 3,5-di-tert.~butyl-4-hydroxybenzoic acid 2,4-di-tert.butyl-phenyl ester or octadecyl ester or 2-methyl-4,6 di-tert.butyl-phenyl ester.

Acrylates, such as, for example, ~-cyano-~,p-di-phenylacrylic acid ethyl ester or isooctyl ester, a-carbomethoxycinnamic acid methyl ester, a-cyano-~-methyl-p-methoxy-cinnamic acid methyl ester or butyl ester and N-(~-carbomethoxy-vinyl)-2-methyl-indoline.

Oxalic acid diamides, such as, for example, 4,4'-di-octyloxy-oxanilide, 2,2'-di-octyloxy-5,5'-di-tert.butyl-oxanilide, 2,2'-di-dodecycloxy-5,5'-di-tert.butyl-oxanilide, 2-ethoxy-2'-ethyl-oxanllide, N,N'-bis-(3-dimethylaminopropyl)-oxalamide, 2-ethoxy-5-tert.butyl-2'-ethyl-oxanilide and lts mixture uith 2-ethoxy-2'-ethyl-5,4'-di-tsrt.butyl-oxanilide and mixtures of ortho- and para-methoxy-as well as of o- and p-ethoxy-disubstituted oxanilides.

~ .
Nickelcompounds, such as , for example, nickel complexes of 2,2'-thio-bis-[4-(1,1,3,3-tetramethylbutyl)-phenol], such as the 1:1 or 1:2 complex, optionally with additional ligands such as n-butylamine, triethanolamine or N-cyclo~
hexyl-diethanolamine, nickel complexes of bis-[2-; .. , . ~ ~ . : ,; : -: : .
. ~ ., : - :. . : :; -. . ,; , ....

.. : ~ , : , ; .: ,,, , ., .:

1~3Ei3~7 hydroxy-4-(1,1,3,3-tetramethylbutyl)-phenyl]-sulphone, such as the 2:1 complex, optionally with additional ligands such as 2-ethyl-caproic acid, nickel dibutyldithiocarbamate, nickel salts of 4-hydroxy-3,5-dl-tert.butylben~yl-phosphonic acid monoalkyl esters, such as the methyl, ethyl or butyl ester, nickel complexes of ketoximes such as of 2-hydroxy-4-methyl-phenyl-undecylketonoxirne and nickel 3,5-di-tert. butyl-4-hydroxy-ben~oate.

Phosphate estersoE the present invention and other ingredlents, if used, may be incorporated into the polymer by any of the usual procedures. For example, the polymer granules may be dry-blended with the phosphate in a high speed mixer and the dispersion fed to a compounder-extruder for melt-blending and finally granulating.
Altsrnatively, the phosphate may be added to the monomer(s) before or during the polymerisation process. The compositions may be used to form flbres, molded articles and the like in accordance with conventional practice.

The phosphate esters described in the invention may be prepared by known methods. For example, the approprLate phenols may be reacted with a phosphorylating agent. The phosphorylating agent may be, for example,phosphorus oxychloride or phosphorus pentachloride.
The phosphorylation reaction may be performed in the presence of a catalyst, such as aluminium ' .:. ; . . `:
... .
:: : . : . :
::. : . . :

3~;3~7 chloride or magnesium chloride, or in the presence of an organic base, such as pyridine. Phosphates may also be prepared by reacting the sodium salt of the phenol with the phosphorylating agent or by oxidising the corresponding phosphorous acid esters by kno~rn procedures.
The following illustrates more fully how phosphate esters of the present invention may be prepared.

81 parts of 2,6-dimethyl phenol were dissol~ed in 739 parts of chloroform. Phosphorus pentachloride was then added to the stirred solution over 1 hour at room temperature until no more would dissolve Approximately 100 parts of phosphorus pentachloride were added. The solut on was then filtered and evaporated to dryness on a rotary evaporator at 90C.
under water pump vacuum. ~ small amount of ethanol was cautiously added to the solid residue and when the exothermic reaction had ceased the crude product was recrystallised twice from aqueous ethanol. The product was dried in a vacuum o~en at 50C. to give 54 parts of tris (2,6-dimethylphenyl) phosphate, a white solid, melting point 136- 138oc.
The product may also be made by the following route:
384 Parts of 2,6 xylenol and 1.3 parts of aluminium chloride were heated with stirring to 90C. and 153.5 parts of phosphorus oxychloride added o~er 1 hour. During the ~113~3~)r7 addition the reaction temperature was gradually increased rrom 90 to 120C. The reaction ~ixture was then heated to 200C. o~er 4 hours and stirred for 5 hour at 200C.
The temperature wa~ then increa3ed to 250C. o~er 1 hour ~nd the reaction mixture stirred for 8 hour~ at 250C.
The crude product was ~tirred ~or 1 hour at 160C.
under water pump ~acuum and then fractlonally distilled under high va~um. The fraç,tion boiling between 200C.
and 202C. under a vacuum of 0.2 mm. mercury wa~ coll~cted to gi~e ~38 parts of tris (2,6 dimethylphenyl) phosphate, which solidified to a white solid9 melting point 13~ - 136~C.

~ .
488 parts of 2,6-dimethylphenol were added to a stirred mixture o~ 307 parts of phosphorus oxychloride and 4 parts of aluminium chloride over 2 hours at 110C. The reaction mixture was heated for 2 hours at 140C. and then fractionally distilled to give 374 parts of bis (2,6-dimethylphenyl) phosphochloridate, boiling point 180C. at 0.4 mm. Hg. The intermediate solidifies to a white solid, melting poi~t 44 - 45C.
243 parts of the abo~re phosphochloridate, 78 parts of phenol and 1 part of aluminium chloride were heated to 240C. over 5 hours and then for a further 5 hours at 240C. The reaction mixture was fra.ctionally ~"' ' ~ " 'I' ::: , :
~:

1~1 3~30r,~

distilled to give 273 parts of bis (2,6-dimethylphenyl) phenyl phosphate, a colourless liquid, boiling point 210C. at 0. 5 mm. Hg.

To a reaction vessel fitted with stirrer, thermometer and reflux condenser was charged 540 parts of naphthalene, 382 parts of paraformaldehyde, and 900 parts of 42. 5% w/w aqueous sulphuric acid. The reaction mixture was heated and stirred at 105C. for three hours and allowed to cool to 60C. 600 parts of water and 1480 parts of chloroform were added, the mixture stirred for 15 minutes at room temperature, and then transferred to a separating funnel. The upper aqueous acid layer was discarded. The lower organio layer was washed five times with 750 parts o~ cold water. Chloroform was removed from the crude product by heating it to 100C. at 20 mm. mercury pressure.
500 parts of water was added and unreacted naphthalene removed by steam distillation. ~inally, the product was dried by heating it at 120C. under nitrogen for 2 hours at 20 mm. mercury pressure.
The product was obtained as 509 parts of a brown plastic solid, softening temperature 50 - 65~C., molecular weight = 500.
The Iollowing Examples further illustrate the invention.

' .. . . ..

36~C

Examples 1 to 11 The compositions shown in Table I were prepared by mi,~ing 100 parts of the poly-2,6-dimethyl-1,4-phenylene oxide/high impact polystyrene poly blend sold B under the Trade ~ ~ Noryl :L10-780 with 10 parts of phosphate for 10 - 15 minutes at 240C. followed by pressing for 10 minutes at 245C. to give a 3 mm.
sheet of test sample. Examination of Table I shows that compositions of the invention have lower burn times than the comparative Example A.
The burn time was measured usi~g the "Test for Flammability for Plastic ~aterials - UL-94" Sept. 17, 1973.
The test i9 carried out on test specimens 6 x ~ x 1/8 inch.
When other sample thicknesses are used the stated thickness is given.
The test specimen is supported from the upper end, with longest dimension vertical, by a clamp on a ring stand 50 that the lower end of the specimen is three-eighths inch above the top of the burner tube. The burner is then placed remote from sample, ignited, and adjusted to produce a blue flame~ three-fourths inch in height.
The test flame is placed centrally under the lower end of the te~t ~pecimen and allowed to remain for 10 seconds. The test flame is then withdrawn, and the duration of flaming combustion of tha specimen noted.

~ , ~ . . . .
- : . : . .

~L~3~

The average of five such burn times is ta~en.
If the specimen drops flaming particles or droplets while burning in this test, this is noted.
In Table II the effect o~ adding phosphates of the invention and a naphthalene oligomer i~ sho~n using a 1.5 mm. polymer sheet. It can be seen that low burn times ara achie~ed coupled with no dripping of the sample.
In Table III the effect of phosphate, oli~omer and calcium carbonate ~iller i9 demonstrated using a 1.5 m~.
polymer sheet. Examples 6, 7 and 8 have low burn times coupled with no dripping.
In Table IV the effect o~ phosphate and oligomer is shown on a 1.5 mm. sheet of a polyphenylene oxide/
high impact polystyrene polyblend sbld under the Trade B ~ Noryl 731-604- Examination of Table IV shows that low burn times and no dripping is achie~ed.

"
.
Phos- Burn ExampleCompound phate time No.~ part 9 A Tri-mesityl phosphate 10 17.8 1 Bis~2,6-dimethyl phenyl) 10 12.0 phenyl phosphate 2 tris(2,6-dimethyl phenyl~ 10 7.4 phos hate I L

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

~3~30 7 Table II. Flame Retardant Noryl 110-780 ~ith ~hosphate and na~h~ ~e ~58~

. - Parts Parts _ __ _ Example Phosphatephos- of time omer 4 Tris (2,6- 18 6 5.8 No dimethyl phenyl).
phosphat~
.~ 15 6 10.8 No ~ None _ _ ~ 3 Yes Table III. Flame Retardant Noryl 110-780 with phosphate.
_' ~

. - - Parts .
Example Phosphate. of Burn No. (parts) ~iller olig- time ----_E~ omer (secs) ~

6 ~ono (2,6- 6 6 6.3 No dimethyl phenyl) diphenyl phosphate (18)

7 tris (~,6- 6 6 4.3 No dimethyl phenyl) phenyl phos-phate (18)

8 Bis (~ t 6- 6 6 6.6 No dimethyl phenyl) .
phosphate ¦18) C None _ ~3 Ye~

:~

:.
' ~3~

and naphthalene oligom0r Example _ . Olig- time No, (parts) , __ _ __ __ __ __ ___ parts ~seos) Drips

9 phenyl) 3 5.5 No phosphate (10) Bis (2,6-dimethyl 3 7.4 No phenyl) phen~l phosphate (10) 11 " (12) 1 6.5 No The compositions shown in Table V were made by mixing 100 parts of the poly-2,6-dimethyl-1,4-phenylene oxide/
high impact polystyrene polyblend sold as Noryl 731-604 with the other ingredients listad and the composition was then formed into sheets 1.5 mm. thick. The burn time was measured using the "Test for Flammability for Plastics Materials -Ul94", September 17, 1973.

The additi~es used were tris(2,6-dimeth~lphenyl) phosphate and the novolak was one o~ the a~erage formula OH O t~

~C H,, '`' `'"':' '~ ' , ~3~3~d~
- 26 _ TABLE V
. _ ~ ~ _ _ Parts ~ Burn He~t Example Phos- Parts Time Oxygen Distortion No-__ ~ Novolak ~ ecs. ~ Index D None None HEI 22.0 127 12 lZ None 12.0 29.8 97 -13 12 1 VE 30.2 98.1 It can be seen that the burning performance of the polymer i~ improved by the addition of the phosphate~ and that the performance is further improved by the addition of the novolal~.

The composition~ shown in Table VI were made by mixing 100 parts of Noryl 731-604 with the other ingredients and the composition was then formed into sheets 4 mm. thick.
The Xeat Distortion Temperature was then measured.
TABLE VI

Example Phosphate (parts) Distortion No. Tem~. C.
. ._ ; E tripheny phosphate 82 tris (2,6 dimethyl phenyl) phosphate (12) 97 ~; ~ ,,,, . _ ~
It can be seen that the Heat Distortion Temperature of Example 15 is improved considerably over comparative Example E containing triphenyl phosphate.

, ,, . A ~ ~
`J ' p `
- ' - '` . ' '; .
,,

Claims (12)

What we claim is.

1. A composition comprising (i) a polymer of styrene or other vinyl aromatic monomer, or a copolymer selected from the group consisting of styrene/a- methyl styrene, styrene/acrylonitrile, styrene/acrylates, acrylo-nitrile/butadiene/styrene, styrene/butadiene (high impact polystyrene), styrene/ethylene, styrene/propylene and styrene/butylene, or a polymer blend selected from the group consisting of polystyrene/polyvinyl chloride, styrene/nitrile rubber, styrene/isopropene rubber, polystyrene/polyphenylene oxide and styrene-butadiene co-polymers/polyphenyleneoxide, and (ii) from 1 to 100 parts by weight per 100 parts of polymer of a triaryl phosphate of the formula where x is 0, 1 or 2 and R1, R2 and R3 are the same or different and represent hydrogen or an alkyl group having 1 to 9 carbon atoms.

2. A composition as claimed in claim 1, in which R1, R2 and R3 are in the 2, 4 and 6 positions.

3. A composition as claimed in claim 1 or 2, in which R1, R2 and R3 are hydrogen or methyl.

4. A composition as claimed in claim 1, in which the polymer is a polyblend of high impact polystyrene and poly-2,6-dimethyl-1,4-phenylene oxide.

5. A composition as claimed in claim 1, in which the phos-phate is tris (2,6-dimethyl phenyl) phosphate.

6. A composition as claimed in claim 1, in which the phos-phate is bis (2,6-dimethyl phenyl) phenyl phosphate.

7. A composition as claimed in claim 1 which also contains an oligomer of the general formula (A)a (-CH2-)b [-CH2(OCH2)mOCH2-]c (-CH2X)d wherein A is at least one aromatic hydrocarbon or hetero-cyclic residue, X is a leaving group, a is 2 to 20, but equals b + c + 1, b is 0 to 19, c is 0 to 19, d is 0 to 2a and m is 0 to 10, there being at least two (-CH2X) groups per molecule, the group (-CH2-0-CH2) counting as (-CH2X) for this purpose when m = 0 and the group (-CH20) counting as a (-CH2X) group when m>1.

8. A composition as claimed in claim 7, wherein greater than 50 mol. % of residues A are derived from naphthalene.

9. A composition as claimed in claim 7, in which X is halogen, -OH, -SH, -NH2, -CO2M, -PO3H2, -OB(OH)2 or a derivative thereof.

10. A composition as claimed in claim 1 which also contains a novolak.

11. A composition as claimed in claim 10, in which the novolak has the general formula , where m represents zero, 1, 2 or 3, the groups R which may be the same or different, each represents an alkyl group, an aryl group, a halogen atom or a hydroxy group. R1 represents hydrogen, an alkyl group of 1 to 4 carbon atoms and n represents zero or a number of average value 1 to 12, and the methylene linkages are ortho and/or para to OR 1 groups.

12. A composition as claimed in claim 11, in which m represents zero, R1 is hydrogen and n has an average value of from 1 to 5.