NEW THIOPHOSPHATE ESTER; ALSO POLYURETHANE FOAM OR PREPOLYMER, CONTAINING TRIS- AND BIS- (2,4,6-TRIBROMOPHENOXY) (THIO) PHOSPHATE

Abstract: A polyurethane foam including prepolymer forms containing a fire wetardant mixture of formulae (XI) and (XII), wherein X1 et X2 are oxygen or sulphur and RO is 2,4,6-tribromophenoxy; and a new compound of formula (II), where RO is as previously defined.

Description: NEW THIOPHOSPHATE ESTER; ALSO POLYURETHANE FOAM OR PREPOLYMER, CONTAINING TRIS- AND BIS- (2,4,6-TRIBROMOPHENOXY) (THIO) Tit1.PHOSPHATE This invention relates to compounds, processes and products. In a particular aspect this invention relates to broninated phenol esters and to their use in mixtures with prepolymers in order to improve certain characteristics of materials to be synthesized from such prepolymers. An additive of this invention is one compound or a mixture of compounds chosen from a group of bro inated phenol esters which ha ve exhibited f ire retardent , surf actant and plasticising properties. In a particular aspect of the present invention there is provided a method of producing fire retardent polyurβthanβ foam wherein the additive is mixed into either an isocyanate prepolymer or a polyol prepoly er of the pαlyurβthane system, and the modified prepolymer thus formed is in turn mixed with polyol prepolymer or isocyanate prepolymer respectively to produce polyurethane foam. The present invention provides a polyurethane foam containing a fire retarding amount of a mixture of a compound of formula XI set out in the accompanying drawings and a compound of formula XII set out in the accompanying drawings wherein X and S 2 are oxygen or sulphur and RO- is 2 , ,6-tribromophβπoxy . The present invention also provides a polyurethane foam prepolymer containing a fire retarding amount, with respect to a foam which can be produced, of a mixture of a compound of formula XI set out in the accompanying drawings and a compound of fornula XII set out in the accompanying drawings wherein X 1 and X 2 * r * oxygen or sulphur and RO- is 2,4,6- tribromophenoxy . Preferably 1 βn d X 2 are both oxygen or both sulphur. The foam or prepolymer may additionally include a compound of formula V set out in the accompanying drawings. The prepolymer may be a polyol or isocyanate. The latter is preferred. The prepolymer preferably comprises an organic base. That base is preferably selected from t r i e thy 1 ami n e , 1 ethyleπe diamine, and triethano 1 amine. 2 Preferably said compound of fornula XI is present in 3 said mixture as from 70 to 80$. 4 Preferably said compound of formula XII is present in 5 said mixture as from 20 to 30J. by weight. 6 Preferably said compound of formula XIII is present in 7 said mixture as from 3 to 8J. by weight. 8 Preferably said mixture is present in said prepolymer 9 as from 2 to 20 preferably 8 to Q% by weight. 10 Preferably said organic base is present in said mixture 11 as from 6 to Q% by weight. 12 The present invention also provides the compound of 13 formula II set out in the accompanying drawings wherein R0- 14 is 2,4,6 -tr ibromophenoxy and mixtures containing same. 15 Various particularly preferred aspects of this 16 invention will now be described. 17 The present invention provides in a preferred aspect 18 for use of five brαminated phenol esters with compound of 19 formulae I-V set out in the accompanying drawings. 20 Compound II, which is the preferred component of the 21 additive does not seem to have been previously described. 22 The use of Compound IV as a fire retardent does not seem to 23 have been described. One previous publication [Benbow & 24 Cullis (1975), Combustion and Flame, v.24, p.217-230] 25 describes the use of Compound III for fire retardation of 26 flexible polyurethane foam. Its use was considered by those 27 authors to be unsa isfactory, primarily because of poor 28 solubility. Use of Compounds I, III, and V for fire 29 retardation of various f lammable materials has been 30 described, but always in applications and combinations 31 distinctly different from those described herein. 32 The widespread sale of urethane prepolymers rather 33 than the finished polymer requires the manufacture of 34 prepolymers with high stability during protracted storage. 35 This imposes strict limitations upon the choice of additives 36 including f ire retardents, primarily because of 37 reci itation and/or neutralization of catalysts during 38 storage. The solubility of purified preparations of Compounds III and V in either type of prepolymer is limited? C ompound I h as much g reater so l ub i l it y , but a t h i gh concentrations it ' stil l tends to precipitate at temperatures below 20°C. However, incompletely esterified preparations of Compound I, that is those which contain some Compound II , are very much more soluble in each prepol ymer. Similarl y, incompletely esterified preparations of Compound III which contain some Compound IV, are very much more soluble in each prepolymer. Either of these preparations alone or when mixed intimately with Conpound V yields easi ly a true solution which seems to be stable indefinitely. The acidity introduced by either Compound II or I V partly neutralizes amine catalysts in the system resulting in a reduced rate of foaming when polyol and isocyanate are mixed. This ef f ect may be at l east in part reduced by addition of an organic base, severa l of which ha ve been tested successful ly. The rema rkab l e ef f ecti v eness of the dies t ers (Compounds I I and I V ) upon th e so l ub i l i ti es o f their corresponding triesters in isocyanate prepolymer is believed to be due to the reversable combination of isocyanate, residues with o n oph o sp h o i c acid residues possib ly as suggested as Reaction 1 in the accompanying drawings wherein R ' represents an organic functional group. The forward reaction is favoured at low tempe a u es, but the balance begins to shift significantly towards the b ack rea ction a t temperatures abo v e 40 ° C. Thus , a t t empera tur es pr oduced b y a n exoth ermic react ion when isocyanate and polyol prepolymers are mixed, isocyanate is released to recσ^ bine immediately with hydroxyl residues to f orm the urethane l inkages. In its esterif ied f orm, the diester (Compound II or I V) is not onl y ful ly solubil ized but also helps to solubilize the triesters, both phosphate (Compound I or III) and phosphite (Compound V), possibly by pi-bonding. An important e f f ect of the p os sib l e chemica l combination of isocyanate with diester and its association with triester, then their re-release during the foaning 1 reaction, is that the uniform dispersion of the esters is 2 thereby promoted. This overcomes one of the main problems 3 with fire retardents in polyurethane prepolymers, namely 4 uneven dispersion and therefore uneven protection against 5 fire. 6 The f ol lowing example provides a process f or 7 manufacture of the additive. The esters were manufactured in 8 acetone solution by esterif icatiαn of bromol (2,4 ,6- 9 tribrαmophenol ) produced in situ from phenol. 10 EXAMPLE 11 In a first procedure, phenol in acetone was mixed 12 with bromine (1:5.2 pheno1/bromine w/w) to form bromol, then 13 this mixture was mixed with phosphorus tribromide (1.05:1 14 pheno 1 /b ro i de w/w) at a temperature betwen 15°C and 30°C, 15 thus forming a solution of tribromol phosphite. The initial 15 phenol concentra ion in acetone was about 80£ w/w, but this 17 value was not critical and was sometimes varied widely 18 according to the mechanics of mixing. This solution was 19 stored under nitrogen until used. 20 In a second procedure, phenol in acetone was mixed 21 with t i oph o spho r y 1 bromide in bromine solution while 22 controlling the temperature to below 30°C. Reactant ratios 23 were 1 :5.2:1.05-1.09 (w/w/w p h en o 1 /b ro ine/b omi de ) , this 24 forming a mixed solution of tribromol thiophosphate (70-8Q!ϊ) 25 with the balance being dibro ol thiophosphate. This solution 25 was then blended with the phosphite solution from the first 27 process (20:1 w/w phospha e/p osphi e) and an amount of 28 organic base (triethy 1amine) sufficient to neutralize 85-95} 29 of residual acidity. This mixture was then poured into water 30 whereupon a white flocculated precipitate separated 31 immediately. This precipitate was then dried to reduce water 32 content bel ow 5 i w/w. The final mixture then became 33 Compounds I/II/V (approx. 15/5/1). 34 I n an a l ternati v e t o th e second p rocedure 35 thiophosphor 1 bromide was replaced by phαsphoryl bromide. 36 Reactant ratios were then 1 :5.2:0.94-0.97. The final mixture 37 then became Compounds II /IV/V (approx. 15/5/1). 38 The preferred additive is Itixture A comprised of 1 Compounds I, II and V (approx. 15/5/1 ). Compound V may be 3- 2 122 of the mixture; about 5 % is considered optimum. 3 Triethy 1 amine is the preferred neutralizing base despite its 4 high f 1 a mma b i 1 i t y ; in practice, it evaporates out αf foam 5 within 1-2 days. 6 Idhen added to isocyanate prepolymer as provided 7 herein mixture A confers the maximum benefits yet found 8 from use of any of the Compounds I-V. This is illustrated 9 in the following table which lists a consensus of opinions 10 of those persons who have studied the burning of 11 polyurethane foams subject of this invention. Although these 12 assessments are subjective, the inventor regards them as the 13 best current indicators of performance because of a lack of 14 objective measures for some cha acteris ics important for 15 performance . 16 A similar mixture, flixture B, was formed containing 17 compounds III, IV and V in similar proportions. 18 The three types αf foam subject of the following 19 table have no remarkable physical differences. The choice of 20 composition of additive for type K foam depends on the 21 relative importance of cost, fire retardency, smoke 22 suppression, and some other physical characteristics 23 conferred upon the foam by the additive. Those other 24 characteristics include (1 ) enhanced surfactaπcy of 5 isocyanate prepolymer which tends to improve cell structure 6 and to reduce or remove the need for silicone, (2) improved 7 adhesion to substrate expected from lowering of silicone 8 addition, (3) reduced need for polymerization catalysts, and 9 (4) anticipated marked suppression of embrittle ent and 0 catastrophic failure caused by normal or premature aging. 1 Compounds I and II are superior to Compounds III and IV with 2 respect to smoke production, catalysis and solubility, but 3 are inferior with respect to f 1 a mma b i 1 i t , stability to 4 aerial oxidation and cost. Compound V is a fire and smoke 5 suppressant in its oun right but in this application it is 6 provided mainly as an antioxidant for mixing with either of 7 the other compounds to confer long term stability. The 8 effects of each αf these compounds seemed to be proportional SUBSTITUTE SHEET T/AU87/00212 to their content. Table. Relative performance of three compositions of polyurethane foam. characteristic type S type G type K 1 ) fire retardency -initial flare 10) 3) 5) )20 )4 )8 -sustained burning 10) 1 ) 3) 2) smoke from burn -carbonaceous 10) 2) 3) )20 )3 )6 -irritating 10) 1 ) 3) 3) integrity after burn -cell structure 10) 7) 2) -collapse, cracks )20 )20 )a and delaminating 10) 13) 6) : 3 =s a Total 60 27 22 Type S, Bayer Desmodur 44V20 + Bayertherm 4150 (1:1 v/v) Type 6, Lackfa Lamoltan Type K: Bayer Desmodur 44 20,nixture A (100:15 w/w) + Bayertherm 4150 (1,1 v v ) f Subject to the above, fixture B performed similarly. SUBSTITUTE SHEET 1 The table summarizes observations made after use and 2 combustion of polyurethane foams of various manufacture, all 3 of which contain additives designed to reduce flammability 4 and smoke evo lution. Such f oams are most dif f icult with 5 respect to minimizing the eff ects of combustion. Their 6 g r e a t e s t a t t r i b u t e , n a m e l y h e a t i n s u l a t i α n , i s 7 simul taneo sly responsib l e for their greatest drawback , 8 namel y f la mabilit , primari ly because their superlati ve 9 insulating capacity ensures very high point temperatures 10 when subjected to heat. Type S foam is a standard, commonly 11 sol d type of pouring f oam. It contains t i s ( c h 1 o o e t h 1 ) 12 p ho spha t e , a t yp e of f i re ret a rdent common l y used in 13 po l yurethane f oam. Typ e 6 i s a p r emium qua l ity f oam 14 containing a dif f erent type of fire retardent with much 15 greater efficacy than that of type S, namely po 1 y br omopheny 1 16 ether. Type K is the standard type S a l tered on l y by 17 addition of the additive of this invention. Thus, the table 18 represents the direct comparison of commercial ly available 19 standard and premium grade foams with the those provided 20 herein . 21 Values for type S have been arbitrarily set at 10; 22 optimum performance would be zero. Thus, low values are 23 preferred. Both type G and type K behave markedly better 24 than type S. Wi h respect to fire and smoke type K is 25 inferior to type G, but type K is so far superior to type G 26 with respect to structural integrity that its overal l 27 performance is significantly better than type G. Type K 28 catches fire and burns at a substantiall lower temperature 29 than the other two t y p a 3. This is by design for good 30 reasons : the l ow burning temperature (1 ) renders 31 extinguishing αf burning foam relatively easy, (2) minimizes 32 the rate of spread of fire and the risk of creation of an 33 explosive firebal l , and (3) minimizes the production of 34 carbon monoxide which is the major cause of death in 35 polyurethane and other polymer fires. Type K fires are far 36 less dramatic than those of type S, but it is anticipated 37 that in widespread use the most significant advance of type 38 K is to be its relatively low potential to produce those gaseous products which are proven potent killers. Use of polyhalogenated diaryl ethers such as those used in ty e G is being voluntarily restricted pending availability of satisfactory alternatives because such compounds are known or suspected precursors of diαxins. Additives αf the type provided herein have no inherent capacity to produce dioxins at the temperatures anticipated in any combustion possibly sustained by type foam. These inventions provided herein have contributed to significant advances in the applicability of polyurethane f oam to situations currently precluded because of flammability. These inventions also provide materials with surfactant and plasticising properties which may be of major, rather than incidental, interest in various applications. The claims form part of the disc l osure of this specifica ion. SUBSTITUTE SHEET

Claims: THE CLAIPIS DEFINING THE INVENTION ARE AS FOLLOMS:- 1. A polyurethane foam containing a fire retarding amount of a mixture of a compound of formula XI and a compound of formula XII HO I RO-P-X, XII f 2 RO wherein X^ and X 2 are oxygen or sulphur and RO-is 2,4,6 - tribromophenoxy . 2. A foam as claimed in claim 1 , wherein X 1 and X 2 are ■ both oxygen or sulphur. 3. A foam as claimed in claim 2, wherein X .. and X 2 are both sulphur . 4. A foam as claimed in claim 2, wherein X. and X 2 are both oxygen. 5. A foam as c laimed in any preceding c l aim and additionally including a compound of formula V. RO f R0-P-0R V wherein RO - is 2 , 4 , 6-tribromophenoxy . 6. A polyurethane foam prepolymer containing a fire retarding amount, with respect to a foam which can be produced, of a mixture of a compound of formula XI RO and a compound of formula XII HO I RO-P-X. XII f RO wherein X^ and X 2 are oxygen or sulphur and R0-is 2,4,6 - tribro ophenoxy. 7. A prepolymer as claimed in claim 6, wherein X .. and X 2 are both oxygen αr sulphur. 8. A prepolymer as claimed in claim 7, wherein X 1 and X 2 are both sulphur. 9. A prepolyner as claimed in claim 7, wherein X 1 and X 2 are both oxygen. 10. A prepolyner as claimed in any one αf claims 6-9 and additionally including a compound of formula V. R0 I R0-P-0R wherein R0 - is 2 , 4 , 6-tribromophenoxy . 11. A prepolymer as claimed in any one of claims 6-10, wherein said prepolymer is an isocyanate. 12. A prepolymer as claimed in any one of claims 6-11 , wherein said prepolymer is a polyol. 13. A prepolymer as claimed in any one of claims 6-12, and including an organic base. 14. A prepolymer as claimed in claim 13, wherein the organic bass is selected from tri e thy 1 ami n e , ethylene diamine, and trlethanola ine . 15. A prepolymer as claimed in any one of claims 6-14, wherein said compound of formula XI is present in said mixture as from 70 to 8QX by weig t. 16. A prepolymer as claimed in any one of claims 6-14, wherein said compound of formula XII is present in said mixture as from 20 to Z 0 f by weight. 17. A prepolymer as claimed in claim 10, wherein said compound of fornula XIII is present in said mixture as from 3 to 3 % by weight. 18. A prepolymer as claimed in any " one of claims 6-17, wherein said mixture is present in said prepolymer as from 2£ to 20 preferably 8 to 10$ by weight. 19. A prepolymer as claimed in claim 13, wherein said organic base is present in said mixture as from 6 to 8% by weight . 20. A compound of formula II HO I R0-P-S R ,.l wherein R0- is 2,4,6- tribromophenoxy. 21. A mixture comprising a compound of formula XI set out in claim 1 and a compound of formula XII set out in claim 1. 22. A mixture as claimed in claim 21 and additional ly containing a compound of formula V set out in claim 5. 23. A f oam , prepol ymer or mixture substantia l l y as hereinbef ore described with ref erence to any one the examples. 24. The articles, things, parts, elements, steps, features, methods, processes, compounds and compositions referred to or indicated in the specification and/or claims of the application individually or collec i ely, and any and all combinations of any two or more of such. SUBSTITUTE SHEET

Inventors: MAERSCHEL RICHARD JOHN, MAERSCHEL, RICHARD, JOHN
Applicants: MAERSCHEL RICHARD JOHN, MAERSCHEL, RICHARD, JOHN
Application year: 1987
Main classification: C07F9
IPC codes: C07F9, C08K5, C08L75