GB2234253A

GB2234253A - Polyester smoke suppressant

Info

Publication number: GB2234253A
Application number: GB9015599A
Authority: GB
Inventors: James Gainer
Original assignee: Ciba Geigy AG
Current assignee: Novartis AG
Priority date: 1989-07-22
Filing date: 1990-07-16
Publication date: 1991-01-30
Anticipated expiration: 2010-07-16
Also published as: CA2021687A1; DE4022999A1; IT9021003A0; IT9021003A1; FR2649984B1; IT1247421B; GB8916824D0; JPH0366726A; GB9015599D0; FR2649984A1; GB2234253B

Abstract

A polyester having an acid value below 3 mg KOH/g is derived from: I(A) an aromatic component which contains 4 carboxyl groups or an anhydride thereof and, optionally, (B) one or more components which contain 2 to 12 carboxyl groups or 1 to 6, carboxylic anhydride groups, selected from: (B1) an aliphatic carboxylic acid component containing 2-16 carbon atoms; (B2) a cyclic non-aromatic carboxylic acid containing 7-16 carbon atoms; and (B3) an aromatic carboxylic acid containing 8-16 carbon atoms; II optionally (C) at least one aliphatic, cycloaliphatic or aromatic polyhydroxyl component containing 2 to 8 hydroxyl groups; and III (D) an alkylene oxide. The polyesters are useful as smoke and toxic gas suppressants for polyurethanes.

Description

- f.

Polvester The present invention relates to the suppression of the formation of smoke and toxic gases in the combustion of natural and synthetic polymeric materials, especially those containing isocyanate moieties, such as flexible and rigid polyurethane foams which are used in furnishings, transport, decoration, insulation and building structures.

Carboxylic acids are well known char-forming systems and are claimed to be useful as smoke suppressant additives in this context. However, acidic compounds react with components which are used in polyurethane manufacture and are very difficult to incorporate into a polyurethane foam, in particular flexible polyurethane foams, and so are unattractive to the foam manufacturer.

Esters of polycarboxylic acid systems are disclosed in EP 75424 as smoke suppressant additives for polyurethanle I foams, but only when used in conjunction with other components. Furthermore, esters of polycarboxylic acids derived from simple monohydric alcohols do not reduce the smoke levels on combustion of the foam.

Surprisingly, we have found that certain polyesters significantly reduce both the rate of formation and the levels of smoke and toxic gases on combustion of the polyurethane foam. Furthermore, these polyesters act alone and do not need the addition of other components, although other components may be used if desired. In addition, the polyesters of the present invention can be readily incorporated into the polyurethane foam under normal manufacturing conditions.

Accordingly, the present invention provides a polyester which has an acid value below 3 mg KOH/g and which is derived from:

I (A) an aromatic component which contains 4 carboxyl groups or an anhydride thereof and optionally, (B) one or more components which contain 2 to 12, preferably 2 to 4, carboxyl groups or 1 to 6, preferably 1 or 2, carboxylic anhydride groups, selected from:

(Bl) an aliphatic carboxylic acid component containing 2-16 carbon atoms; (B2) a cyclic non-aromatic carboxylic acid containing 7-16 carbon atoms; and (B3) an aromatic carboxylic acid containing 8-16 carbon atoms; II optionally (C) at least one aliphatic, cycloaliphatic or aromatic, preferably aliphatic, polyhydroxyl component containing 2 to 8, preferably 2 to 4, hydroxyl groups; and III (D) an alkylene oxide Examples of suitable acid components [A] include pyromellitic, naphthalene tetracarboxylic, 3,31,4,41-benzophenonetetracarboxylic, 3,3f, 4,41-diphenyltetracarboxylic, 3,314,4fdiphenyl ether tetracarboxylic and, 3,314,41-diphenyl sulphone tetracarboxylic acids, related anhydrides and halogenated derivatives thereof. Preferably component [A] is pyromellitic acid or pyromellitic dianhydride.

Aliphatic carboxylic acid component (B 1] may be saturated or unsaturated, preferably saturated and may be unsubstituted or substituted with one or more halogen, amino or, preferably, hydroxyl groups. Examples of suitable aliphatic acids include oxalic, malonic, succinic, glutaric and adipic acids, commercially available mixtures of dicarboxylic acids e.g. AGS 1 3 i (mixtures of adipic, glutaric and succinic acids), pimelic, azelaic, sebacic, malic, tartaric, citric, dibromosuccinic, ethylenediaminetetracarboxylic, maleic, fumaric, itaconic, _methyleneglutaric, dichloromaleic and polymaleic acids and related anhydrides. Preferably (B 1) is a saturated acid, more preferably a dicarboxylic acid, especially adipic acid.

Cyclic non-aromatic acid component [B 2] may be interrupted by an -0- atom or substituted by one or more ketone groups. Examples of suitable acids include cyclopentane or cyclohexane polycarboxylic acids, cyclopentanone or cyclohexanone polycarboxylic acids, tetrahydrofuran polycarboxylic acid and related anhydrides. Tetracarboxylic acids, particularly tetrahydrofuran tetracarboxylic acid, and their anhydrides are preferred.

Aromatic acid component IB 31 may contain 2 to 4 carboxyl groups or one or two anhydride groups and may be unsubstituted or substituted by one or more halogen atoms. Examples of suitable acids include phthalic, isophthalic, terephthalic, naphthalene dicarboxylic, trimellitic, naphthalene tetracarboxylic, 3,31,4,41-benzophenonetetracarboxylic, and 3, 3",4,41-diphenyltetracarboxylic acids, related anhydrides and halogenated derivatives thereof e.g. 3,5,6-tribromotrimellitic acid or anhydride. Dicarboxylic acids are preferred as (B3), particularly phthalic, isophthalic and terephthalic acids.

The polyhydroxyl component [C] may be aliphatic, cycloaliphatic or aromatic, 6ptionally substituted with one or more halogen atoms. It may be a saturated aliphatic polyol containing from 2 to 52 carbon atoms and from 2 to 4 hydroxyl groups or a cyclo aliphatic alcohol containing from 6 to 10 4 - carbon atoms and from 2 to 4 hydroxyl groups.

Examples of suitable aliphatic diol components [C] include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,10-decane diol, diethylene glycol, polyoxyalkylene glycols of various molecular weights such as polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 1000, polypropylene glycol 200, polypropylene glycol 425, polypropy.lene glycol 700, and polypropylene glycol 1000, and halogen-substituted glycols such as dibromoneopentyl glycol. Examples of suitable components containing three of four hydroxyl goups [C] include trimethylolethane, 1,1,1-'trimethylol propane, 1,2,6-hexanetriol, glycerol and pentaerythritol.

Examples of suitable cycloaliphatic polyols are cyclohexane-1,2 or 1,4 dimethanols; and cyclohexanone or cyclohexanol-2,2.',6,61-tetramethanols.

Examples of suitable aromatic polyol component [C] include diols such as catechol, resorcinol, hydroquinone, naphthalene diols, bisphenol A, anthraquinone diols, benzene 1,2-or 1,4-dimethanols; diphenyl-4,41dimethanol and halogenated derivatives thereof.

Component (C) is preferably a component of the polyester and is preferably aliphatic, more preferably a diol, especially diethylene glycol or a polyoxyalkylene glycol.

Examples of suitable alkylene oxides (D) are ethylene oxide, propylene oxide or mixtures thereof.

The polyesters of the invention may be prepared by 1 conventional procedures known to those skilled in the art, such as esterification or transesterification. Thus the preparation may comprise reacting a polycarboxylic acid or anhydride (A) and any other acidic components (B) with the polyhdroxy component (C) at a temperature from 20C to 300C, for example using the polyol (C) as solvent, or in the presence of another suitable solvent such as methyl ethyl ketone, tetrahydrofuran, toluene or xylene, until the acid value is in the range of from 10 mg KOH/g to 100 mg KOH/g, preferably from 20 mg KOH/g to 40 mg KOH/g, and treating the resulting polyester with an aklylene oxide (D), preferably using a suitable catalyst such as sodium bicarbonate, and preferably in a solvent such as toluene or xylene, until the acid value is below 3 mg KOH/g. The reaction between (A), (B) and (C) may be performed in the presence of a catalyst such as tin or titanium alkoxides, N-methylimidazole, triethylene diamine, triphenyl phosphine, p- toluenesulfonic acid or other catalysts known to those skilled in the art.

Alternatively the polycarboxylic acid or anhydride (A) and any other acidic components (B) may be reacted directly with the alkylene oxide (D) until the acid value is below 3 mg KOH/g.

The smoke suppressant polyesters of the present invention can be utilized in various plastics materials, but they are especially suited to materials incorporating isocyanate linkages, particularly polyisocyanurates and polyurethanes, notably the flexible or rigid foams commonly based on toluene diisocyanate (TDI) and diphenylmethane-4,41- diisocyanate (MDI). and, especially, the flexible foams, usually based on TDI, which are employed in modern furnishings, fixtures and fittings. These polyurethanes, can be based, for example, on polyester or polyether polyols, trialkanolamines, or aminic 6 - polyols, e.g. those derived from alkylene oxide adducts of amines and ammonia. Examples of polyether polyols are those based on copolymers of ethylene and/or propylene oxides as well as modified polyols such as polymer polyols (e.g. polyether polyols to which polyvinyl fillers have been grafted), polyether polyols containing dispersed particles of polyurea or polyether polyols containing reaction products of polyhydroxyamino compounds and polyisocyanates. Examples of polyester polyols include poly(oxidiethylene adipates), poly(oxydiethylene terephthalates) and polycaprolactones. They may incorporate various blowing agents such as wLter, carbon dioxide and perhalohydrocarbons, such as methylene chloride, liquified gases which have boiling points below 27C and above 15C, or other inert gases, such as nitrogen, carbon dioxide added as such, methane, helium, and argon. Suitable initially liquified gases include aliphatic and cycloaliphatic fluorocarbons which vaporize at or below the temperature of the foaming mass. Such gases are at least partially fluorinated and may also be otherwise halogenated. Illustrative of the preferred fluorocarbon blowing agents are trichloromonofluoromethane; dichlorodifluoromethane; 1,1-dichloro-l- fluoroethane; hexafluorocyclobutane; and octafluorocyclobutane. Other adjuvants (or residues thereof) which may be incorporated include catalysts, e.g. tin compounds such as stannous octoate, dibutyl tin acetate, and dibutyl tin laurate, surfactants and emulsifiers such as substituted nonyl phenols, fatty acid/ethylene oxide condensates, alkylene oxide block copolymers or siliconcontaining compounds such as poly(dimethylsiloxanes), poly(phenylmethylsiloxanes) or poly(dimethylsiloxane)polyoxyalkylene graft copolymers, as well as fireretardants, such as hydrated aluminas, magnesium hydroxide, halogenand/or phosphorus-containing compounds including metal salts of phosphonic acids, antimony oxides, boron-containing compounds such as borax, graphite, e.g. exfoliated graphite, ceramics or melamine or its derivatives such as melamine salts. Suitable melamine salts include melamine borate, melamine cyanurate, dimelamine phosphate, melamine phosphonates, melamine sulphonates, and melamine carboxylates such as melamine phthalate, melamine stearate and melamine oxalate. When a fire- retardant is used the ratio of polyester to fire retardant in the combustible material may be from 10:90 to 90:10 by weight. If desired, intumescing ingredients e.g. ammonium polyphosphates may be included in the formulation.

Apart from tin compounds, the catalyst preferably comprises an amine. Suitable amine catalysts include one or more of the following; N,NIdimethylcyclohexylamine; methyl dicyclohexylamine; N-methylmorpholine; Nethylmorpholine; N-octyadecylmorpholine; triethylamine; tributylamine; trioctylamine; N,N,Nt,N"-tetramethylenediamine; N,N,N1,Nt-tetramethyl-1, 3butane-diamine; triethanolamine, N,N-dimethylethanolamine; triisopropanolamine; N-methyl-diethanolamine; bis(2-dimethylaminoethyl)ether; hexadecyldimethylamine; N,N-dimethylbenzylamine; trimethylamine; triethylenediamine (i.e. 1,4-diazabicyclo[2.2.2-octanel); the formate and other salts of triethylene- diamine; oxyalkylene adducts of the amine groups of primary and secondary amines and other such amine catalysts which are well known in the art of polyurethane manufacture.

Accordingly, the present invention also provides a composition comprising a combustible material, preferably a polyurethane foam, containing urethane linkages and, as smoke and toxic gas suppressant, a polyester of the invention. The polyester may be incorporated by mixing with the polyol formulation used to make the polyurethane before it is mixed with the isocyanate component. The polyester, which is itself a polyol, may be used in an amount which constitutes 5 to 100%, preferably 10 to 30%, by weight of the polyol. The polyester may therefore comprise all of the polyol used to make the polyurethane.

Thus the invention also provides a polyurethane, particularly a polyurethane foam, formed from a di- or poly-isocyanate and a polyester as defined above.

The compositions of the present invention may be used in a wide variety of products such as chairs, settees, stools and various other forms of seating, matresses, cushions, pillows, foam backing for carpets, curtains and textile composites as well as foams for thermal and sound insulations. In such applications they will often be used in composites or assemblies with a wide range of other materials including natural and synthetic textiles for example leather, cotton, wool, polyester, polyamide, acrylic, polyvinylchloride, polypropylene, viscose velor; supplementary padding, interlinings, webbing, barriers and other various materials of construction such as wood, metals, plastics, plasterboard, glass fibres etc. In addition other means of reducing flammability, and smoke and toxic gas evolution may also be included, such as interliners, barrier foams and flame retarded textiles.

The following Examples illustrate the invention.

Exam-ple 1: 30.5 g (0.12 mole) pyromellitic acid, 17.5 g (0.12 mole) adipic acid and 127.2 g (1.20 mole) diethylene glycol are charged to a reaction vessel fitted with an efficient stirrer and heated slowly to 200C under a stream of nitrogen 1 1 gas. The mixture is heated at this temperature, and water of condensation is distilled from the reaction mass at a head temperature of 100C ( 5C). The reaction is monitored by acid value determinations. At an acid value of 20 mg KOH/g, the reaction mixture is cooled and the apparatus adapted for reflux. 232 g (4 mole) propylene oxide, 200 mls toluene and a catalytic amount of sodium hydrogen carbonate are charged to the mixture. The reaction is again monitored by acid value determinations until an acid value of < 2 mg KOH/g is reached. Excess propylene oxide, toluene and diethylene glycol are removed under reduced pressure to give an oil with acid value 1.9 mg KOH/g, hydroxyl value 309 mg KOH/g and viscosity 9. 875 Pa s.

Exam.ple- 2: 30.5 g (0.12 mole) pyromellitic acid, 17.5 g (0.12 mole) adipic acid and 127.2 g (1.20 mole) diethylene glycol are charged to a reaction vessel fitted with an efficient stirrer and heated slowly to 200C under a stream of nitrogen gas. The mixture is heated at this temperature, and water of condensation is distilled from the reaction mass at a head temperature of 100C ( 5'C). The reaction is monitored by acid value determinations. At an acid value of 30 mg KOH/g, the reaction mixture is cooled and the apparatus adapted for reflux. 116 g (2 mole) propylene oxide, 200 mls toluene and catalytic amount of sodium hydrogen carbonate are charged to the mixture. The reaction is again monitored by acid value determinations until an acid value of < 2 mg KOH/g is reached. Excess propylene oxide, toluene and diethylene glycol are removed under reduced pressure to give an oil with acid value 2.8 mg KOH/g, hydroxyl value 326 mg KOH/g and viscosity 8.900 Pa s.

a Example 3: 65.4 g (0.3 mole) pyromellitic dianhydride, 1200 g (1.2 mole) polypropylene glycol 1000 are charged to a reaction vessel and heated slowly to 200C under a stream of nitrogen gas. The mixture is heated at this temperature, and water of condensation is distilled from the reaction mass at a head temperature of 100C ( 5C). The reaction is monitored by acid value determinations. At an acid value of 23.7 mg KOH/g, the reaction mixture is cooled and the apparatus adapted for reflux. 174 g (3.0 moles) propylene oxide and a catalytic amount of sodium hydrogen carbonate are charged to the mixture.

The reaction is again monitored by acid value determinations until an acid value of < 2 mg KOH/g is reached. Excess propylene oxide is removed under reduced pressure to give an oil with acid value 1.9 mg KOH/g, hydroxyl value 112 mg KOH/g and viscosity 0.7 724 Pa s.

Example 4: 50.8 g (0.2 mole) pyromellitic acid, 116.0 g (2.0 mole) propylene oxide and 100 mls tetrahydrofuran are charged to a reaction vessel fitted with an efficient stirrer and heated slowly to reflux temperature. The reaction is monitored by acid value determinations. At an acid value of 59 mg KOH/g, a catalytic amount of sodium hydrogen carbonate is added, and the acid value monitored until a value of 42 mg KOH/g is obtained. The reaction mixture is evaporated to dryness and the resulting oil charged to a reaction vessel with 58.0 g (1.0 mole) propylene oxide and 100 mls toluene, and heated slowly to reflux temperature. At an acid value of 9 mg KOH/g a further catalytic amount of sodium hydrogen carbonate is added and the reaction monitored until an acid value of < 2 mg KOH/g is obtained. Excess propylene oxide and toluene are removed under reduced pressure to give an oil with acid value 1.0 mg KOH/g and hydroxyl value 321 mg KOH/g.

j The use of the new polyester compositions of the present invention as additives which effectively reduce the amount of smoke and toxic gases evolved from burning flexible polyrethane foam is illustrated by the following Examples 4-6.

Example 5: A flexible polyurethane foam is prepared using the following formulation.

Parts bv weiaht Polyether polyol 1 Water N,N-dimethylethanolamine Dibutyl tin dilaurate silicone surfactant 2 Toluenediisocyanate 80:20 (TDI) 1 Caradol R 48/2 ex Shell Chemicals 2 Polyurax R SC 246 ex BP Chemicals 100.0 4.7 0.4 0.25 1.0 55.5 The polyol, water, N,N-dimethylethanolamine and silicone surfactant are blended together using a four-bladed impeller at 2000 rpm.

The dibutyl tin dilaurate is added and stirred for five seconds. Finally preweighed TDI is added rapidly. The mixture is blended for 5 seconds then poured into a mould. The foam is allowed to rise and then stored for 24 hours at 23C and 50 % relative humidity.

The foam is cut into cubes weighing 5 g ( 0.2 g) and the amount of smoke produced on burning is measured as follows using a standard Aminco NBS Smoke Chamber described in ASTM E662 but using a modified test procedure. The foam sample is placed on a wire gauze supported on a tripod within the smoke chamber and ignited with a match. Each foam sample is tested in triplicate. The mean specific optical density is calculated at times of one minute (D 1), two minutes (D 2) and three minutes (D 3) from the time of ignition. The mean maximum specific optical density corrected for soot deposition on the lenses [Dmax (corr)] is also recorded. The results are given in Table 1.

Examples 6 and 7: Samples of flexible polyurethane foam containing the polyester compositions of the present invention are prepared using the method of Example 5 with the appropriate amount of the polyester composition being blended into the mixture prior to the addition of the dibutyl tin dilaurate and TDI. The amounts used are shown in Table 1 as parts per hundred parts of polyol (php).

Although the said polyester compositions can be used without the need for any substantial changes to this formulation, those skilled in the art will appreciate that small modifications e.g. to catalyst levels, may be made to control the properties of the foam produced.

Samples of the resulting foam are prepared and tested following the procedure described in Example 5 and the values of optical density thus obtained are given in Table 1.

lExamplel Product of jAmount I Optical Densities No. Example php D 1 D 2 D 3 D max (corr)l 1 5 Control - 1 85 85 85 83 1 6 1 1 30 1 6 41 48 48 1 7 2 30 1 8 34 36 37 1 A - 13 The results given in Table 1 show that incorporation of the polyesters of the invention into the flexible polyurethane foam reduces the total amount of smoke formed during combustion compared to the untreated foam (Example 5) as measured by Dmax (corr). Additionally, the polyesters have the effect of significantly reducing the rate at which the smoke is produced as measured by the values of optical density after 1, 2 and 3 minutes (D,. D 2 and D 3)- The following Example illustrates the use of the new polyesters of the present invention as the polyol component of a flexible polyurethane foam.

Example 8: A flexible foam is prepared by the method of Example 5 but using the following formulation. Parts bv weiQht 100.0 5.0 1.5 2.0 0.15 66.0 Product of Example 3 Water N-methylmorpholine Silicone surfactant Stannous octoate Toluenediisocyanate 2 The foam obtained is tested for smoke evolution using the method of Example 5. The results obtained are as follows and show that the foam gives a lower smoke output than the control foam (Example 5).

O-Ptical Densities D 1 D 2 D 3 48 69 72 D max (corr) 72

Claims

Claims: 1. A polyester which has an acid value below 3 mg KOH/g and which

is derived from: I (A) an aromatic component which contains 4 carboxyl groups or an anhydride thereof and, optionally, (B) one or more components which contain
2 to 12 carboxyl groups or 1 to 6 carboxylic anhydride groups, selected from: (B1) an aliphatic carboxylic acid component containing 2-16 carbon atoms; (B2) a cyclic non-aromatic carboxylic acid containing 7-16 carbon atoms; and (B3) an aromatic carboxylic acid containing 8-16 carbon atoms; H optionally (C) at least one aliphatic, cycloaliphatic or aromatic polyhydroxyl component containing 2 to 8 hydroxyl groups; and M (D) an alkylene oxide. 2. A polyester as claimed in claim 1, in which the component (A) is pyromellitic acid or pyromellitic dianhydride.
3. A polyester according to claim 1 or 2 wherein component (B) is a saturated aliphatic carboxylic acid component (B1).
4. A polyester according to claim 3 wherein component (B1) is a dicarboxylic acid.
5. A polyester according to claim 4, wherein component (B1) is adipic acid.
6. A polyester according to claim 1 or 2, wherein component (B) is a cyclic non-aromatic component (B2) which is a tetracarboxylic acid or an anhydride thereof.
7. A polyester according to claim 1 or 2 wherein component (B) is an aromatic component (B3) containing 2 carboxyl groups.
8. A polyester according to any of the preceding claims, wherein component (C) is a component of the polyester and is aliphatic.
9. A polyester according to claim 8, wherein component (C) is a diol.
10. A polyester according to claim 9, wherein component (C) is diethylene glycol or a polyoxyalkylene glycol.
11. A polyester according to any of the preceding claims, in which component (D) is ethylene oxide, propylene oxide or a mixture thereof.

j i
12. A process from the preparation of a polyester according to any of the preceding claims, which comprises reacting (A), or (A) and (B), with the polyhydroxy component (C) at a temperature of from 201C to 3001C until the acid value is in the range of from 1Orng KOEVg to 100 mg KOH1g, and then treating the resulting polyester with an alkylene oxide (D) until the acid value is below 3 mg KOH/g.
13. A process for the preparation of a polyester according to any of claims 1 to 11, which comprises reacting (A), or (A) and (B), with an alkylene oxide (D) until the acid value is below 3 mg KOH1g.
14. A composition comprising a combustible material containing urethane linkages and, as smoke and toxic gas suppressant, a polyester according to any of claims 1 to 11.
15. A composition according to claim 14, in which the combustible material is a polyurethane foam.
16. A composition according to claim 15, in which the amount of polyester is from 5 to 100% by weight of the polyol used to make the polyurethane foam.
17. A composition according to claim 16, in which the amount of polyester is from 10 to 30%.
18. A composition according to any of claims 14 to 17, which also contains a fire retardant.
19. A composition according to claim 18 in which thefire retardant is selected from hydrated aluminas, magnesium hydroxide, halogen - and/or phosphorus- containing compounds, antimony oxides, boron-containing compounds, graphite, ceramics or melamine or a derivative thereof.
20. A composition according to claim 18 or 19, in which the ratio of polyester to fire retardant is from 10:90 to 90: 10 by weight.
2 1. A polyurethane formed from a di - or poly-isocyanate and a polyester according to claim 1.
22. A polyurethane according to claim 21, which is a polyurethane foam.

0 1
23. A polyester according to claim 1, substantially as described in any of Examples 1 to 4.
24. A composition according to claim 14, substantially as described in any of Examples 5 to 7.
25. A polyurethane according to claim 21, substantially as described in Example 8.

J J published 1991 at 7be Patent Oflicc.StatL House, 66/71 High Holborn, London WC I R47?. Further copies Tn2Y be obtained from NPI 7HZ Printed by Multiplex techniques ltd. St Mary Cray. Kent Sales Branch, Unit 6. Nine Mile Point. Cwmrclinfach. Cross Keys. Newport,