IT9021003A1 - USEFUL POLYESTERS AS SUBSTANCES THAT ELIMINATE SMOKE AND TOXIC GASES FOR POLYURETHANE - Google Patents

Description

DESCRIPTION OF THE INDUSTRIAL INVENTION

Polyesters Useful as Smoke Eliminating Substances and Toxic Gases for Polyurethanes The present invention relates to elimination

the formation of smoke and toxic gases in the

combustion of natural polymeric substances e

synthetic, especially those containing portions

of isocyanate, for example flexible and rigid polyurethane foam materials, which are used

in the manufacture of furniture, in the sector of

transport, in decorative, insulating structures and in

building structures.

Carboxylic acids are well known carbonizing systems and are claimed to be useful

acting as additives to eliminate smoke in this

context. However, acidic compounds react with

components that are used in the production of

polyurethanes and which are very difficult to introduce

in a polyurethane foam material, in particular

flexible polyurethane foam materials and, thus,

they are of no interest to the material manufacturer

expanded.

Esters of polycarboxylic acid systems are

disclosed in EP 75424 as smoke suppression additives for polyurethane foam materials, but only when used in conjunction with other components. Furthermore, esters of polycarboxylic acids derived from simple monohydric alcohols do not decrease the level of smoke upon combustion of the foamed material.

Surprisingly, the Applicant has found that certain polyesters considerably decrease both the rate of formation and the levels of smoke and toxic gases upon combustion of the polyurethane foam material. Furthermore, these polyesters act alone and do not require the addition of other components, although other components may be used if desired. Furthermore, the polyesters of the present invention can be easily incorporated into the polyurethane foam material under normal manufacturing conditions.

Therefore, the present invention provides a polyester which has an acid number lower than 3 mg KOH / g and which is derived from:

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

(B1) a component of an aliphatic carboxylic acid which contains from 2 to 16 carbon atoms;

(B2) a cyclic non-aromatic carboxylic acid containing 7 to 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, polyhydroxy component containing from 2 to 8, preferably from 2 to 4 hydroxyl groups; And

III (D) an alkylene oxide.

Examples of suitable acidic components [A3 include pyromellitic, naphthalene-tetracarboxylic acids, 3,3 ', 4,4'-benzophenontetracarboxylic, 3,3', 4,4'-diphenyltetracarboxylic, 3,3 ', - 4 , 4 '-diphenylether-tetracarboxylic and, 3, 3', 4,4 '-sulfonetetracarboxylic diphenes, relative anhydrides and their halogenated derivatives. Preferably, component 1A3 is pyromellitic acid or is pyromellitic acid dianhydride.

A component consisting of an aliphatic carboxylic acid [B <1>] can be saturated or unsaturated, preferably saturated, and can be unsubstituted or substituted with one or more halogens, amino groups or, preferably, hydroxyl groups. Examples of suitable aliphatic acids include oxalic, mayionic, succinic, glutaric and adipic acids, commercially available mixtures of dicarboxylic acids for example AGS (mixtures of adipic, glutaric and succinic acids), pimelic, azelaic, sebacic acids, malic, tartaric, citric, dibromosuccinic, ethylenediaminetetracarboxylic, maleic, fumaric, itaconic, methyleneglutaric, dichloromal and polymeric and relative anhydrides. Preferably (Β1) is a saturated acid, more preferably it is a dicarboxylic acid, in particular adipic acid.

The cyclic non-aromatic acid component [B <2>] can be interrupted by an -0- atom or it can be substituted with one or more ketone groups. Examples of suitable acids include cyclopentane- or cyclohexane-polycarboxylic acids, cyclopentanone-polycarboxylic acid or cyclohexanone-polycarboxylic acid, tetrahydrofuran-polycarboxylic acid and related anhydrides. Tetracarboxylic acids are preferred, in particular tetrahydrofuran-tetracarboxylic acid and their anhydrides.

The aromatic acid component [B <3>] can contain from 2 to 4 carboxylic groups or 1 or 2 anhydride groups and can be unsubstituted or can be replaced with one or more halogen atoms. Examples of suitable acids include phthalic, isophthalic, terephthalic, naphthalene dicarboxylic, trimellitic, naphthalene-tetracarboxylic, 3,3 ', 4,4'-benzophenontetracarboxylic acids and 3,3', 4,4'-diphenyltetracarboxylic acid. , relative anhydrides and their halogenated derivatives, for example 3, 5,6-tribromotrimellitic acid or relative anhydride. Dicarboxylic acids are preferred as (B3), in particular phthalic, isophthalic and terephthalic acids.

The polyhydric component [C] can be aliphatic, cycloaliphatic or aromatic, optionally substituted with one or more halogen atoms. It can be a saturated aliphatic polyol containing from 2 to 52 carbon atoms and from 2 to 4 hydroxyl groups or it can be a cycloaliphatic alcohol containing from 6 to 10 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-decanediol, diethylene glycol, polyoxyalkylene glycols of different molecular weights e.g. polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 1000, polypropylene glycol 200, polypropylene glycol 425, polypropylene glycol 700 and polypropylene glycol 1000 and glycols substituted with halogens such as dibromoneopentyl glycol. Examples of suitable components containing 3 or 4 hydroxy groups [C] include trimethylolethane, 1,1-trimethylolpropane, 1,2,6-hexantriol, glycerol and pentaerythritol.

Examples of suitable cycloaliphatic polyols include cyclohexane-1, 2-or 1,4-dimethanol; and cyclohexanone-or cyclohexanol-2,1,6,6'-tetramethanol.

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

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

Examples of suitable alkylene oxides (D) are ethylene oxide, propylene oxide or their mixtures. The polyesters of the present invention can be prepared by conventional methods known to those skilled in the art such as esterification or transesterification. Thus, the preparation may consist in making a polycarboxylic acid or an anhydride of a polycarboxylic acid (A) and any other acid component (B) react with the polyhydric component (C) at a temperature between 20 ° C and 300 ° C , for example using polyol (C) as a solvent, or in the presence of another suitable solvent such as methylethylketone, tetrahydrofuran, toluene or xylene, until the acid number is between 10 mg KOH / g and 100 mg KOH / g , preferably until the acid number is between 20 mg KOH / g and 40 mg KOH / g and treat the polyester obtained with an alkylene oxide (D), preferably using a suitable catalyst such as sodium bicarbonate and preferably in a solvent such as toluene or xylene, as long as the acid number is less than 3 mg KOH / g. The reaction between (A), (B) and (C) can be carried out in the presence of a catalyst for example tin alkoxides or titanium alkoxides, N-methylimidazole, triethylenediamine, triphenylphosphine, p-toluenesulfonic acid or other known catalysts to those who are experts in the field. ; Alternatively, the polycarboxylic acid or its anhydride (A) and any other acid component (B) can be reacted directly with the alkylene oxide (D) until the acid number is less than 3 mg KOH / g. The smoke suppressing polyesters of the present invention can be used in various plastics, but they are particularly suitable for materials in which isocyanate bonds are incorporated, particularly polyisocyanurates and polyurethanes, mainly flexible or rigid foam materials commonly based on toluene-diisocyanate (TDI) and diphenylmethane-4,4 '-diisocyanate (MDI) and, in particular, the flexible foam materials usually based on TDI, which are used in modern furniture, tools and connecting pipes. These polyurethanes can be based, for example, on polyester polyols or on polyether polyols, trialkanolamines or amino polyols, for example those derived from addition products of alkylene oxides of amines and ammonia. Examples of polyether-polyols are those based on copolymers of ethylene oxide and / or propylene oxides and also on modified polyols for example polymer polyols (for example polyether polyols to which polyvinyl fillers have been grafted), polyether polyols containing dispersed particles of polyurea or polyether polyols containing reaction products of polyhydroxyamine compounds and polyisocyanates. Examples of polyester polyols include poly (oxyethylene adipates), poly (oxyethylene terephthalates) and polycaprolactones. Various swelling agents can be incorporated in them, such as water, carbon dioxide and peralohydrocarbons for example methylene chloride, liquefied gases that have boiling points below 27 ° C and above 15 ° C, or other inert gases such as nitrogen, anhydride added carbon as such, methane, helium and argon. Suitable initially liquefied gases include aliphatic and cycloaliphatic fluorinated hydrocarbons which vaporize at the temperature of the expansion mass or below the temperature of the expansion mass. Such gases are at least partially fluorinated and can also be otherwise halogenated. Illustrative examples of the preferred fluorinated hydrocarbon swelling agents are trichloromonofluoromethane; dichlorodifluoromethane; 1,1-dichloro-1-fluoroethane; hexafluorocyclobutane; and octafluorocyclobutane. Other adjuvant substances (or residues thereof) which may be introduced include catalysts, for example tin compounds such as stannous octoate, dibutyl tin acetate and dibutyl tin laurate, surfactants and emulsifiers such as substituted nonyl phenols, acid condensation products fat / ethylene oxide, alkylene oxide block copolymers or compounds containing silicon, for example. polyhydimethyl siloxanes), poly (phenylmethylsiloxanes) or graft copolymers poly (dimethylsiloxane) - polyoxyalkylene and also substances which retard the spread of flame, such as hydrated aluminas, magnesium hydroxide, compounds containing halogen and / or containing phosphorus including metal salts of phosphonic acids, antimony oxides, compounds containing boron such as borax, graphite, for example a defoliated graphite, ceramic materials or melamine or its derivatives such as melamine salts. Suitable melamine salts include melamine borate, melamine cyanurate, dimelamine phosphate, melamine phosphonates, melamine sulfonates, and melamine carboxylates, such as melamine phthalate, melamine stearate and melamine oxalate. When using a flame retardant agent, the ratio of polyester to flame retardant in the combustible material can be from 10:90 to 90:10 by weight. If desired, intumescent ingredients, for example ammonium polyphosphates, may be introduced into the formulation. In addition to tin compounds, the catalyst preferably contains an amine. Suitable amine catalysts include one or more of the following: Ν, Ν'-dimethylcyclohexylamine; methyl-dicyclohexyl-amine; N-methylmorpholine; N-ethylmorpholine; N-octadecylmorpholine; triethylamine; tributylamine, triotylamine, Ν, Ν, Ν ', N1-tetramethylenediamine; Ν, Ν, -Ν ', Ν'-tetramethyl-1,3-butan-diamine; triethanolamine; Ν, Ν-dimethylethanolamine; triisopropanolamine; N-methyl-diethanolamine; bis (2-di-methylaminoethyl) -ether; hexadecyldimethylamine; Ν, Ν-dimethylbenzylamine; trimethylamine; triethylenediamine (i.e. 1,4-diazabicyclo (2.2.2-octaneJ); formate and other triethylene diamine salts; oxyalkylene addition products of the amino groups of primary and secondary amines and other e.g. amine-based catalysts which are well known in the field of polyurethane production.; Therefore, the present invention further provides a composition which comprises a combustible substance, preferably a polyurethane foam material, containing urethane linkages and, as a substance which eliminates smoke and toxic gases, a polyester of the present invention. The polyester can be incorporated by mixing with the polyol formulation used to prepare the polyurethane before mixing it with the isocyanate component. The polyester, which is itself a polyol, can be used in an amount which is between 5% and 100% preferably between 10% and 30% by weight of the polyol. Therefore, the polyester can constitute all the polyol used. or to prepare the polyurethane. Thus, the present invention also provides a polyurethane, in particular a polyurethane foam material formed by a diisocyanate or a polyisocyanate and a polyester as defined above. The compositions of the present invention can be used in a wide variety of products such as chairs, sofas, booster seats and various other forms of seats, mattresses, upholstery, cushions, foam backs for carpets, curtains and textile composites and also materials foams for thermal and acoustic insulation. In such applications, the compositions of the present invention will often be used in composites or in assemblies with a wide range of other materials including natural and synthetic textile materials, e.g. leather, cotton, wool, polyester, polyamide, acrylic compounds. , polyvinyl chloride, polypropylene, viscous velvets; additional padding, interlinings, textures, barriers and other different construction materials such as wood, metals, plastics, plaster materials, glass fibers, etc. In addition, other means can also be introduced to reduce flammability and the development of smoke and toxic gases, for example interlayers, barrier foam materials and flame retardant textiles.

The following examples illustrate the present invention.

Example 1; 30.5 g (0.12 moles) of pyrometolytic acid, 17.5 g (0.12 moles) of adipic acid and 127.2 g (1.20 moles) of diethylene glycol are placed in a reaction vessel equipped with an effective stirrer and are slowly heated to 200 ° C under a stream of nitrogen gas. The mixture is heated to this temperature and the condensation water is distilled from the reaction mass with a head temperature of 100 ° C (. ±. 5 ° C). The reaction is controlled by making acid number determinations. At an acid number of 20 mg KOH / g, the reaction mixture is cooled and the apparatus is adapted, for reflux. 232 g (4 moles) of propylene oxide, 200 ml of toluene and a catalytic quantity of sodium bicarbonate are introduced into the mixture. The mixture is checked again by determining the acid number until an acid number lower than 2 mg KOH / g is reached.

Excess propylene oxide, toluene and diethylene glycol are removed under reduced pressure thus obtaining an oil having an acid number of 1.9 mg KOH / g, a hydroxyl number of 309 mg KOH / g and a viscosity of 9.875 Pa s.

Example 2: 30.5 g (0.12 moles) of pyromellitic acid, 17.5 g (0.12 moles) of adipic acid and 127.2 g (1.20 moles) of diethylene glycol are introduced into a reactor equipped with an effective stirrer and are slowly heated to 200 ° C under a stream of nitrogen gas. The mixture is heated to this temperature and the condensation water is distilled from the reaction mass at a head temperature of 100 ° C (+ 5 ° C). The reaction is controlled by acid number determinations. At an acid number of 30 mg KOH / g, the reaction mixture is cooled and the equipment is adapted for reflux. 116 g (2 moles) of propylene oxide, 200 ml of toluene and a catalytic quantity of sodium bicarbonate are introduced into the mixture. In this case too, the reaction is controlled by determining the acid number until an acid number lower than 2 mg KOH / g is reached. Excess propylene oxide, toluene and diethylene glycol are removed under reduced pressure thus obtaining an oil having an acid number of 2.8 mg KOH / g, a hydroxyl number of 326 mg KOH / g and a viscosity of 8,900 Pa s.

Example 3: 65.4 g (0.3 moles) of pyromellic dianhydride 1200 g (1.2 moles) of propylene glycol 1000 are introduced into a reactor and slowly heated to 200 ° C under a nitrogen gas flow. The mixture is heated to this temperature and the condensation water is distilled from the reaction mass at a head temperature of 100 ° C (+ _ 5 ° C). The reaction is controlled by acid number determinations. At an acid number of 23.7 mg KOH / g, the reaction mixture is cooled and the equipment is adapted for reflux. 174 g (3.0 moles) of propylene oxide and a catalytic quantity of sodium bicarbonate are introduced into the mixture.

The reaction, also in this case, is controlled by determining the acid number until an acid number lower than 2 mg KOH / g is reached. The excess propylene oxide is removed at reduced pressure thus obtaining an oil having an acid number of 1.9 mg KOH / g, a hydroxyl number of 112 mg KOH / g and a viscosity of 0.7724 Pa s.

Example 4: 50.8 g (0.2 mol) of pyromellitic acid, 116.0 g (2.0 mol) of propylene oxide and 100 ml of tetrahydrofuran are introduced into a reactor equipped with an efficient stirrer and are heated slowly up to the reflux temperature. The reaction is controlled by determining the acid number. At an acid number of 59 mg KOH / g, a catalytic quantity of sodium bicarbonate is added and the acid number is controlled until a value of 42 mg KOH / g is obtained. The reaction mixture is evaporated to dryness and the oil obtained is introduced into a reactor together with 58.0 g (1.0 moles) of propylene oxide and 100 ml of toluene and slowly heated up to the reflux temperature. At an acid number of 9 mg KOH / g, a further catalytic quantity of sodium bicarbonate is added and the reaction is controlled until an acid number lower than 2 mg KOH / g is obtained. Excess propylene oxide and toluene are removed under reduced pressure thus obtaining an oil having an acid number of 1.0 mg KOH / g and a hydroxyl number of 321 mg KOH / g.

The use of the novel dipolyester compositions of the present invention as additives which effectively reduce the amount of smoke and toxic gases developed by the combustion of a flexible polyurethane foam is illustrated by the following Examples 4-6.

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

Polyol, water, Ν-dlmethylethanolamine and silicone surfactant are mixed together using a 4-blade agitator at 2000 rpm.

The dibutyl tin dilaurate is added and stirred for 5 seconds. Finally, the pre-weighed TDI is quickly added. The mixture is stirred for 5 seconds, then poured into a mold. The foam is allowed to expand and then it is kept for 24 hours at 23 ° C and 50% relative humidity.

The foam is cut into cubes having a weight of 5 g (_ + 0.2 g) and the amount of smoke produced upon combustion 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 inside the smoke chamber and burned with a match. Each sample of foam material is examined by carrying out 3 tests.

The average specific optical density is calculated at 1 minute (D1), 2 minutes (D2) and 3 minutes (D) starting from the moment of combustion. The average maximum specific optical density corrected for the soot deposit on the lenses is also recorded tDmax (corr) l. The results are shown in Table 1.

Examples 6 and 7: Samples of flexible polyurethane foam material containing the polyester compositions of the present invention are prepared by adopting the method of Example 5 by mixing the appropriate amount of the polyester composition in the mixture before adding the dibutyl tin dilaurate and TDI. The quantities used are indicated in Table 1 as parts per hundred parts of polyol (php).

Although polyester compositions can be used without the need for any substantial change for this formulation, those skilled in the art will understand that small changes can be made, for example in the amounts of catalyst, in order to control the properties. of the foam material produced.

Samples of the foam material thus obtained are prepared and examined following the procedure described in Example 5 and the values of the optical density thus obtained are indicated in Table 1.

The results indicated in table 1 indicate that the introduction of the polyesters of the present invention into the flexible polyurethane foam material decreases the total amount of smoke formed during combustion, compared to the untreated foam material (example 5) measured by Dmax (corr) . Furthermore, polyesters have the effect of significantly decreasing the rate at which smoke is produced,

measured with the optical density values after 1 minute, 2 minutes and 3 minutes (D 1, D, and D).

The following example illustrates the use of the new polyesters of the present invention as a polyol component of a flexible polyurethane foam material.

Example 8: A flexible foam material is prepared by the method of Example 5, but using the following formulation.

The foam material obtained is examined as regards the development of smoke by adopting the method of Example 5. The results obtained are the following and indicate that the foam material emits a lower quantity of smoke than that of the control foam material ( example 5).

Optical density

Claims (20)

CLAIMS 1) Polyester which has an acid number lower than 3 mg KOH / g and which is derived from: I (A) an aromatic component containing 4 carboxylic groups or one of its anhydrides and, optionally, (B) one or more components containing from 2 to 12 carboxylic groups or from 1 to 6 carboxylic anhydride groups, selected from: (B1) a component consisting of an aliphatic carboxylic acid containing 2-16 carbon atoms; (B2) a non-aromatic, cyclic 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 polyhydric component, containing from 2 to 8 hydroxyl groups; And III (D) an alkylene oxide. 2) Polyester as claimed in claim 1, in which component (A) is pyromellitic acid or is pyromellitic dianhydride. 3) Polyester according to claim 1, in which the component (B) is a component consisting of a saturated aliphatic carboxylic acid (B1). 4) Polyester according to claim 3, in which the component (B1) is a dicarboxylic acid. 5) Polyester according to claim 4, in which the component (B1) is adipic acid. 6) Polyester according to claim 1, wherein the component (B) is a cyclic non-aromatic component (B2) which is a tetracarboxylic acid or an anhydride thereof. 7) Polyester according to claim 1, wherein the component (B) is an aromatic component (B3) which contains 2 carboxyl groups. 8) Polyester according to claim 1, wherein the component (C) is a component of the polyester and is aliphatic. 9) Polyester according to claim 8, wherein the component (C) is a diol. 10. Polyester according to claim 9, wherein the component (C) is diethylene glycol or is a polyoxyalkylene glycol. 11) Polyester according to claim 1, in which the component (D) is ethylene oxide, propylene oxide or a mixture thereof. 12) Process for the preparation of a polyester according to claim 1, which consists in making (A), or (A) and (B) react with the polyhydric component (C) at a temperature between 20 ° C and 300 ° C until the acid number is between 10 mg KOH / g and 100 mg KOH / g and, then treat the polyester obtained with an alkylene-oxide (D) until the acid number is less than 3 mg KOH / g . 13) Process for the preparation of a polyester according to claim 1 which consists in making (A), or (A) and (B) react with an alkylene-oxide (D) until the acid number is less than 3 mg KOH / g. 14. Composition containing a combustible material containing urethane bonds and, as a substance which eliminates smoke and toxic gases, a polyester according to claim 1. 15. Composition according to claim 14, in which the combustible material is a polyurethane foam material. 16. Composition according to claim 15, in which the amount of polyester is comprised between 5% by weight and 100% by weight of the polyol used to prepare the polyurethane foam material. 17. Composition according to claim 16, in which the amount of polyester is between 10% and 30%. 18. Composition according to claim 14, which further contains a flame retardant substance. 19) A composition according to claim 18, in which the flame retardant agent is selected from hydrated aluminas, magnesium hydroxide, halogen-containing and / or phosphorus-containing compounds, antimony oxides, compounds containing boron, graphite, ceramic materials or melamine or a derivative thereof. 20) Polyurethane foam material formed by a diisocyanate or a polyisocyanate and a polyester according to claim 1.