Hydroxyl-containing poly(alkylene phosphates)

Abstract

Flame retardant compositions for polyurethanes may include hydroxyl-containing poly(alkylene phosphates) that have 5 mol % or less of phosphorus from phosphorus-containing compounds having a .sup.31P NMR resonance signal at a chemical shift in the range from 13 ppm to 18 ppm relative to 85 wt % phosphoric acid.

Claims

1. A hydroxyl-containing poly(alkylene phosphate) composition having a reduced residual content of undesired phosphorous-containing byproducts, the composition comprising at least one hydroxyl-containing poly(alkylene phosphate) of formula (I) ##STR00011## where n is an integer from 1 to 100, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 independently of one another represent a C.sub.1- to C.sub.8-alkyl radical, or a radical of formula (CHR.sup.5CHR.sup.6O).sub.mH, where m is an integer from 1 to 5, and R.sup.5 and R.sup.6, independently of one another, represent hydrogen or methyl, with the proviso that one or more of the radicals R.sup.1, R.sup.2, R.sup.3 and R.sup.4, but not simultaneously all of the radicals R.sup.1, R.sup.2, R.sup.3 and R.sup.4, represent a radical of formula (CHR.sup.5CHR.sup.6O).sub.mH, and A represents a straight-chain or branched C.sub.4- to C.sub.20-alkylene radical, or a C.sub.3- to C.sub.6-cycloalkylene radical, or a radical of formula CH.sub.2CHCHCH.sub.2, a radical of formula CH.sub.2CCCH.sub.2, a radical of formula CHR.sup.5CHR.sup.6(OCHR.sup.7CHR.sup.8).sub.a, a radical of formula CHR.sup.5CHR.sup.6S(O).sub.bCHR.sup.7CHR.sup.8, or a radical of formula (CHR.sup.5CHR.sup.6O).sub.cR.sup.9(OCHR.sup.7CHR.sup.8).sub.d, where a is an integer from 0 to 5, b is an integer from 0 to 2, c and d are independently of one another an integer of 1 to 5, R.sup.5, R.sup.6, R.sup.7 and R.sup.8, independently of one another, represent hydrogen or methyl, R.sup.9 represents the radical CH.sub.2CHCHCH.sub.2, the radical CH.sub.2CCCH.sub.2, a 1,2-phenylene radical, a 1,3-phenylene radical, a 1,4-phenylene radical, or a radical of formula (II) ##STR00012## or a radical of formula (III) ##STR00013## or a radical of formula (IV) ##STR00014## or a radical of formula
C(O)R.sup.12C(O), wherein R.sup.10 and R.sup.11 each, independently of one another, represent hydrogen or C.sub.1- to C.sub.4-alkyl, or R.sup.10 and R.sup.11 together with the carbon atom to which they are bonded represent an optionally alkyl-substituted carbocyclic ring having 4 to 8 carbon atoms, and R.sup.12 represents a straight-chain or branched C.sub.2- to C.sub.8-alkylene radical, a C.sub.3- to C.sub.6-cycloalkylene radical, a 1,2-phenylene radical, a 1,3-phenylene radical, or a 1,4-phenylene radical, wherein, in a .sup.31P NMR spectrum of the composition in CDCl.sub.3 as solvent, with 85 wt % phosphoric acid as external standard, undesired phosphorous-containing byproducts produce resonance signals from 13 to 18 ppm, and, for the composition, an area under all resonance signals from 13 to 18 ppm is about 5 percent or less of the total area of all resonance signals from 30 to 200 ppm.

2. The composition according to claim 1, wherein, in the at least one hydroxyl-containing poly(alkylene phosphate) of formula (I), n is an integer from 1 to 10, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 independently of one another represent ethyl, n-propyl, isopropyl, n-butyl or isobutyl or a radical of formula (CHR.sup.5CHR.sup.6O).sub.mH, where m is an integer from 1 to 2, and R.sup.5 and R.sup.6, independently of one another, represent hydrogen or methyl, with the proviso that one or more of the radicals R.sup.1, R.sup.2, R.sup.3 and R.sup.4, but not simultaneously all of the radicals R.sup.1, R.sup.2, R.sup.3 and R.sup.4, represent a radical of formula (CHR.sup.5CHR.sup.6O).sub.mH, and A represents a straight-chain C.sub.4- to C.sub.6-alkylene radical or a radical of formula
CHR.sup.5CHR.sup.6(OCHR.sup.7CHR.sup.8).sub.a, where a is an integer from 0 to 2, and R.sup.5, R.sup.6, R.sup.7 and R.sup.8, independently of one another, represent hydrogen or methyl.

3. The composition according to claim 1, wherein, in the at least one hydroxy-containing poly(alkylene phosphate) of formula (I), n is an integer from 1 to 10, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 independently of one another represent ethyl, n-propy or n-butyl or a radical of formula (CHR.sup.5CHR.sup.6O).sub.mH, where m is 1 or 2, and R.sup.5 and R.sup.6, independently of one another, represent hydrogen or methyl, with the proviso that one or more of the radicals R.sup.1, R.sup.2, R.sup.3 and R.sup.4, but not simultaneously all of the radicals R.sup.1, R.sup.2, R.sup.3 and R.sup.4, represent a radical of formula (CHR.sup.5CHR.sup.6O).sub.mH, and A represents a straight-chain C.sub.4-alkylene radical or a radical of formula
CHR.sup.5CHR.sup.6(OCHR.sup.7CHR.sup.8).sub.a, where a is 0 or 1, R.sup.5 and R.sup.6, independently of one another, represent hydrogen or methyl, and R.sup.7 and R.sup.8 are identical and represent hydrogen.

4. The composition according to claim 1, wherein, in the at least one hydroxy-containing poly(alkylene phosphate) of formula (I), n is an integer from 1 to 10, R.sup.1, R.sup.2, R.sup.3 and R.sup.4, independently of one another, represent ethyl, or the radical CH.sub.2CHCH.sub.3OH, or the radical CHCH.sub.3CH.sub.2OH, wherein one or more of the radicals R.sup.1, R.sup.2, R.sup.3 and R.sup.4, but not simultaneously all of the radicals R.sup.1, R.sup.2, R.sup.3 and R.sup.4, represent CH.sub.2CHCH.sub.3OH or CHCH.sub.3CH.sub.2OH, A represents the radical CH.sub.2CH.sub.2OCH.sub.2CH.sub.2; the total area under all resonance signals from 30 to 200 ppm relates to the sum of all phosphorus atoms present in the composition, wherein the area under all resonance signals from 13 to 18 ppm in relation to the total area under all resonance signals from 30 to 200 ppm, corresponds to mol % of the undesired phosphorous-containing byproducts, and the composition contains about 5 mol percent or less of the undesired phosphorous-containing byproducts; and the undesired phosphorous-containing byproducts that produce the resonance signals from 13 to 18 ppm comprise cyclic five-membered phosphoric esters having at least one structural unit of formula ##STR00015##

5. The composition according to claim 1, having a hydroxyl number of 15 to 300 mg KOH/g.

6. The composition according to claim 1, having a viscosity at 23 C. of 10 mPas to 10,000 mPas.

7. The composition according to claim 1, wherein the composition is a flame retardant for synthetic polymers, modified or unmodified natural polymers, wood-based materials, leather or paper.

8. A flame retardant preparation comprising the composition according to claim 1 and at least one auxiliary/added substance.

9. A process for producing a flame retardant polyurethane comprising the composition according to claim 1, the process comprising reacting at least one organic polyisocyanate with at least one polyol component containing at least two isocyanate-reactive hydrogen atoms with customary blowing agents, stabilizers, activators and/or further customary auxiliary/added substances in the presence of the composition according to claim 1.

10. The composition according to claim 1, wherein the total area under all resonance signals from 30 to 200 ppm relates to the sum of all phosphorus atoms present in the composition, and the area under all resonance signals from 13 to 18 ppm in relation to the total area under all resonance signals from 30 to 200 ppm, corresponds to mol % of undesired phosphorous-containing byproducts and the composition contains about 5 percent or less of the undesired phosphorous-containing byproducts.

11. The composition according to claim 1, wherein the undesired phosphorous-containing byproducts that produce resonance signals from 13 to 18 ppm comprise cyclic five-membered phosphoric esters having at least one structural unit of formula ##STR00016##

12. The composition according to claim 1, wherein: the area under all resonance signals from 13 to 18 ppm is about 3 percent or less of the total area of all resonance signals from 30 to 200 ppm; and the composition contains about 3 mol percent or less of the undesired phosphorous-containing byproducts.

Description

EXAMPLES

(1) The parts referred to in what follows are parts by weight.

Synthesis Example S1

(2) Synthesis of a Poly(Alkylene Chlorophosphate) of Formula (V), where a Represents the Radical CH.sub.2CH.sub.2OCH.sub.2CH.sub.2 (as Per Example S4 in EP 2 687 534 A1)

(3) In a reactor fitted with a stirrer, thermometer, dropping funnel, reflux cooler and vacuum means, 118.7 parts of diethylene glycol were added dropwise to 306.7 parts of phosphorus oxychloride at 10-20 C. and 500-700 mbar. On completion of the dropwise addition, the pressure was reduced further to a final pressure of 5-15 mbar, and the temperature raised to 20-30 C. A virtually colourless liquid residue comprising 37.4 wt % of chlorine remained.

Synthesis Examples S2 to S4

(4) Synthesis of Inventive Compositions Comprising Hydroxyl-Containing Poly(Alkylene Phosphates) of Formula (I) where the Radicals R.sup.1, R.sup.2, R.sup.3 and R.sup.4 Represent Either Ethyl or the Radical CH.sub.2CHCH.sub.3OH or CHCH.sub.3CH.sub.2OH, Wherein One or More of the Radicals R.sup.1, R.sup.2, R.sup.3 and R.sup.4 Represents CH.sub.2CHCH.sub.3OH or CHCH.sub.3CH.sub.2OH and a in Each Case Represents the Radical CH.sub.2CH.sub.2OCH.sub.2CH.sub.2.

(5) In a reactor fitted with a stirrer, thermometer, dropping funnel, reflux cooler and vacuum means, the amounts of ethanol and water indicated in table 1 were admixed with stirring at 15 C. with the indicated amount of poly(alkylene chlorophosphate) from example S1. The reaction mixture was stirred for a further four hours and then freed of volatile constituents by distillation. The residue that remained was reacted at 70 C. with the indicated amount of propylene oxide. Finally, the volatile constituents were in turn removed completely by distillation. A residue of the product in the form of a colourless liquid remained. The analytical results are likewise summarized in table 1.

(6) TABLE-US-00001 TABLE 1 Raw materials employed (parts by weight) for producing the synthesis examples S2 to S4 and properties of the products. Synthesis example Unit S2 S3 S4 poly(alkylene parts by weight 100.7 203.8 100.1 chlorophosphate) from example S1 ethanol parts by weight 163.8 326.8 163.5 water parts by weight 6.67 28.78 31.15 water/(water + ethanol) mol/mol .Math. 100% 9% 18% 33% propylene oxide parts by weight 39.5 148.6 116.7 acid number mg KOH/g 0.22 0.31 0.05 hydroxyl number mg KOH/g 86 122 166 viscosity mPas at 23 C. 134 273 786 integral of the signals area % 1.7% 2.1% 4.1% between 13 and 18 ppm in the .sup.31P NMR Spektrum

Synthesis Example S5 to S7

(7) Synthesis of Hydroxyl-Containing Poly(Alkylene Phosphates) Based on Phosphorus Pentoxide as Per EP 0 771 810 A1 (Non-Inventive)

(8) A reactor fitted with a stirrer, thermometer, powder funnel, reflux cooler and vacuum means was initially charged with the amount of ethanol indicated in table 2. The indicated amount of phosphorus pentoxide was added portionwise such that the temperature did not exceed 40 C. Once addition was complete the mixture was heated to 80 C. and held at this temperature for six hours. The mixture was then cooled to 60 C. and the powder funnel was exchanged for a dropping funnel from which the indicated amount of propylene oxide was added dropwise. The reaction temperature was gradually increased from 60 C. to 100 C. over the course of this addition. Once the dropwise addition was complete the mixture was held at 100 C. for one hour. Finally, the volatile constituents were removed completely by distillation. A brown, liquid residue remained.

(9) TABLE-US-00002 TABLE 2 Raw materials employed (parts by weight) for producing the noniventive synthesis examples S5 to S7 and properties of the products. Example Unit S5 S6 S7 phosphorus pentoxide parts by weight 283.9 42.58 42.58 ethanol parts by weight 184.3 27.64 23.04 propylene oxide parts by weight 645.0 112.6 132.2 acid number mg KOH/g 0.16 4.75 0.24 hydroxyl number mg KOH/g 165 155 77 integral of the signals area % 16.4% 22.2% 35.1% between 13 and 18 ppm in the .sup.31P NMR Spektrum
Production of Flexible Polyurethane Foams

(10) TABLE-US-00003 TABLE 3 Raw materials employed for producing inventive flexible polyurethane foams (examples B1 to B3) and noninventive flexible polyurethane foams (comparative examples V1 to V4) Component Function Description A polyol Arcol 1105 (Bayer MaterialScience), polyether polyol with OHN 56 mg KOH/g B blowing water agent C catalyst Addocat 108 (Rhein Chemie), 70% solution of bis(2-dimethylaminoethyl) ether in dipropylene glycol D catalyst Addocat SO (Rhein Chemie), tin(II) 2-ethylhexanoate E stabilizer Tegostab B 8232 (Degussa), silicone stabilizer F1 flame tris(2,3-dichloroisopropyl) phosphate, retardant TDCP F2 flame Disflamoll DPK (LANXESS Deutschland retardant GmbH), diphenyl cresyl phosphate F3 flame product from synthesis example S5 retardant (noninventive) F4 flame product from synthesis example S2 retardant (inventive) F5 flame product from synthesis example S3 retardant (inventive) F6 flame product from synthesis example S4 retardant (inventive) G diisocyanate Desmodur T 80 (Bayer MaterialScience), tolylene diisocyanate, isomer mixture
Production of Flexible Polyurethane Foams

(11) The raw materials for producing flexible polyurethane foams are specified in table 3. The components specified in table 4 in terms of type and amount with the exception of the diisocyanate (component G) were stirred to afford a homogeneous mixture. The diisocyanate (component G) was then added and briefly stirred in vigorously. This increased the amount of diisocyanate as a function of the hydroxyl number of the flame retardant such that an equal index (ratio of amount of isocyanate to hydroxyl groups) of 108 was maintained in all formulations. After a cream time of 15-20 s and a full-rise time of 140-180 s a flexible polyurethane foam having an envelope density of 33 kg/m.sup.3 was obtained. All experiments afforded uniformly fine-celled foams.

(12) Determination of Flame Retardancy

(13) The flexible polyurethane foams were tested in accordance with the specifications of Federal Motor Vehicle Safety Standards FMVSS-302 and classified according to the flammability ratings SE (self-extinguishing), SE/NBR (self-extinguishing/no burn rate), SE/BR (self-extinguishing/with burn rate), BR (burn rate) and RB (rapid burn). The flammability tests were carried out five times for each example. The poorest result for each series of five is shown in table 4.

(14) Fogging Determination

(15) The fogging behaviour of the flexible polyurethane foams was analyzed as per DIN 75201 B. The measured condensate amounts after storage for 16 hours at 100 C. are shown in table 4.

(16) TABLE-US-00004 TABLE 4 Flexible polyurethane foam composition (parts by weight) and test results for inventive examples B1 to B3 and noninventive comparative examples V1 to V4 Example V1 V2 C3 C4 B1 B2 B3 A 100 100 100 100 100 100 100 B 3.0 3.0 3.0 3.0 3.0 3.0 3.0 C 0.08 0.08 0.08 0.08 0.08 0.08 0.08 D 0.16 0.16 0.16 0.16 0.16 0.16 0.16 E 0.80 0.80 0.80 0.80 0.80 0.80 0.80 F1 6 F2 6 F3 6 F4 6 F5 6 F6 6 G 40.9 40.9 40.9 42.6 41.8 42.1 42.6 MVSS rating RB SE BR SE SE SE SE fogging condensate 0.12 0.79 0.72 1.74 0.36 0.27 0.25 [mg] as per DIN 75201 B
Evaluation of Flexible Polyurethane Foam Test Results

(17) In the absence of a flame retardant (comparative example V1) the flexible polyurethane foam burns rapidly (MVSS flammability rating RB) but exhibits a very low fogging value. A foam comprising tris(dichloroisopropyl) phosphate (comparative example V2) exhibits a substantial flame retardant additive fogging contribution and achieves the best MVSS flammability rating SE (self-extinguishing) in all repetitions of the flammability test. However, tris(dichloroisopropyl) phosphate brings with it the abovedescribed disadvantages of a halogen-containing flame retardant. While the use of the halogen-free flame retardant diphenyl cresyl phosphate (comparative example V3) circumvents this problem and also achieves a low fogging value, the flame retardancy, of MVSS flammability rating BR, is insufficient. The flame retardant employed in comparative example V4 has a very good flame retardancy (MVSS flammability rating SE, i. e. self-extinguishing) but exhibits relatively high fogging values attributable to cyclic phosphates.

(18) The examples B1 to B3 show that the flexible polyurethane foams according to the invention achieve the best flammability rating SE (self-extinguishing) in all repetitions of the flammability test and also have the lowest fogging values.