Phosphorous containing flame retardants

Abstract

The present invention relates to a phosphorus containing polyol, obtainable or obtained by a process comprising the reaction of at least one polyol with a phosphorus containing compound of the general formula (I) as defined herein, as well as the process for preparing a phosphorus containing polyol, comprising the reaction of at least one polyol with a phosphorus containing compound of the general formula (I). Furthermore, the present invention relates to the use of a phosphorus containing polyol as disclosed herein as a flame retardant, to a process for the preparation of a polyurethane and the polyurethane as such. ##STR00001##

Claims

1. A phosphorus-comprising polyol, obtained by a process comprising reacting at least one polyol with a phosphorus-comprising compound of formula (I): ##STR00008## wherein X represents Cl, Br, I, alkoxy, or hydrogen, Y represents O or S, t is 0 or 1, R1 and R2 independently represent C1-C16-alkyl, C2-C16-alkenyl, C2-C16-alkynyl, C1-C16-alkoxy, C2-C16-alkenoxy, C2-C16-alkynoxy, C3-C10-cycloalkyl, C3-C10-cycloalkoxy, aryl, aryloxy, C6-C10-aryl-C1-C16-alkyl, C6-C10-aryl-C1-C16-alkoxy, C1-C16-alkyl-C6-C10-aryl, or C1-C16-alkyl-C6-C10-aryloxy, wherein the phosphorus-comprising polyol comprises at least one phosphorus-comprising group of formula (II): ##STR00009## wherein Y represents O or S, t is 0 or 1, R1 and R2 independently represent C1-C16-alkyl, C2-C16-alkenyl, C2-C16-alkynyl, C1-C16-alkoxy, C2-C16-alkenoxy, C2-C16-alkynoxy, C3-C10-cycloalkyl, C3-C10-cycloalkoxy, aryl, aryloxy, C6-C10-aryl-C1-C16-alkyl, C6-C10-aryl-C1-C16-alkoxy, C1-C16-alkyl-C6-C10-aryl, or C1-C16-alkyl-C6-C10-aryloxy, wherein at least one of R1 and R2 represents C1-C16-alkyl, C2-C16-alkenyl, C2-C16-alkynyl, C2-C16-alkenoxy, C2-C16-alkynoxy, C3-C10-cycloalkyl, aryl, C6-C10-aryl-C1-C16-alkyl, or C1-C16-alkyl-C6-C10-aryl; wherein the polyol is a polyether polyol produced from an epoxide, wherein a phosphorus content of the phosphorus-comprising polyol is at least 7% to 12% by weight, wherein the phosphorus-comprising polyol is halogen-free, wherein the phosphorus-comprising polyol has an OH-functionality of from 2 to 4 and a molecular weight of from 100 to 700 g/mol; wherein the phosphorus-comprising polyol is flame retardant.

2. The phosphorus-comprising polyol according to claim 1, wherein the phosphorus is present in a form of phosphate or a phosphinate group.

3. A process for preparing a phosphorus-comprising polyol, the process comprising reacting at least one polyol with a phosphorus-comprising compound of formula (I): ##STR00010## wherein X represents Cl, Br, I, alkoxy, or hydrogen, Y represents O or S, t is 0 or 1, R1 and R2 independently represent C1-C16-alkyl, C2-C16-alkenyl, C2-C16-alkynyl, C1-C16-alkoxy, C2-C16-alkenoxy, C2-C16-alkynoxy, C3-C10-cycloalkyl, C3-C10-cycloalkoxy, aryl, aryloxy, C6-C10-aryl-C1-C16-alkyl, C6-C10-aryl-C1-C16-alkoxy, C1-C16-alkyl-C6-C10-aryl, or C1-C16-alkyl-C6-C10-aryloxy, wherein the phosphorus-comprising polyol comprises at least one phosphorus-comprising group of formula (II): ##STR00011## wherein Y represents O or S, t is 0 or 1, R1 and R2 independently represent C1-C16-alkyl, C2-C16-alkenyl, C2-C16-alkynyl, C1-C16-alkoxy, C2-C16-alkenoxy, C2-C16-alkynoxy, C3-C10-cycloalkyl, C3-C10-cycloalkoxy, aryl, aryloxy, C6-C10-aryl-C1-C16-alkyl, C6-C10-aryl-C1-C16-alkoxy, C1-C16-alkyl-C6-C10-aryl, or C1-C16-alkyl-C6-C10-aryloxy, wherein at least one of R1 and R2 represents C1-C16-alkyl, C2-C16-alkenyl, C2-C16 alkynyl, C2-C16-alkenoxy, C2-C16-alkynoxy, C3-C10-cycloalkyl, aryl, C6-C10-aryl-C1-C16-alkyl, or C1-C16-alkyl-C6-C10-aryl; wherein the polyol is a polyether polyol produced from an epoxide, wherein a phosphorus content of the phosphorus-comprising polyol is at least 7% to 12% by weight, and wherein the phosphorus containing polyol is halogen-free wherein the phosphorus-comprising polyol has an OH-functionality of from 2 to 4 and a molecular weight of from 100 to 700 g/mol; wherein the phosphorus-comprising polyol is flame retardant.

4. A flame retardant, comprising the phosphorous-comprising polyol according to claim 1.

5. A process for preparing a polyurethane, the process comprising introducing the phosphorus-comprising polyol according to claim 1 into the process.

6. A process for preparing a polyurethane, the process comprising reacting at least one isocyanate (a), at least one polyol (b) and at least one phosphorus-comprising polyol according to claim 1.

7. The process according to claim 6, wherein the at least one phosphorus-comprising polyol is used in an amount of 1 to 30% of a total of all polyols.

8. A polyurethane, obtained by the process according to claim 6.

9. The polyurethane according to claim 8, wherein the polyurethane is a polyurethane foam.

10. A flame retardant, comprising a phosphorus-comprising polyol obtained from the process according to claim 3.

11. A process for preparing a polyurethane, the process comprising introducing a phosphorus-comprising polyol into the process, wherein the phosphorus-comprising polyol is obtained from the process according to claim 3.

Description

EXAMPLES

1. Synthesis of a Phosphorous Containing Polyol

(1) In a 6 L Miniplant-reactor the polyol (Glycerol, ethoxylated (>1<6,5 mol EO); 787 g, 2.5 mol) was dissolved in methylenchloride (3 L) and triethylamine (323 g, 3.2 mol) under an inert atmosphere (N.sub.2-inertisation). Chloro diphenylphosphate (839 g, 3.1 mol) was added during 45 min (dosage rate: 1119 g/h). The reaction temperature did not exceed 33° C. during dosage of chloro diphenylphosphate. After completion of the dosage the reaction mixture was stirred at reflux conditions (inner temperature: 42° C.), then at ambient temperature for additional 12 h.

(2) After that, the reaction mixture was subsequently extracted with water (1×1.5 L), NaOH (1×1.0 L, 5% w/w), and water (2×1.0 L), respectively. The aqueous phases were discarded. The resulting organic phase was dried over MgSO.sub.4 (1.5 kg) over night and filtered utilizing a glass filter frit (D3). The filter cake was washed with additional methylene chloride (0.5 L). The aqueous phases were combined and methylene chloride was quantitatively removed in vacuo via distillation (final conditions: 7 mbar, 80° C.).

(3) The product was isolated as a clear colorless oil (1087 g).

(4) OH-number: 100 mg KOH/g, according to DIN 53240;

(5) acid number: <0.5 mg KOH/g according to DIN EN ISO 2114.

(6) Phosphorus content: 7.4% (elemental analysis).

2. Synthesis of Polyurethanes

(7) 2.1 Synthesis of a Polyurethane Flexible Foam

(8) Polyurethane foams were produced as indicated in table 1 and table 2 by first mixing all of the components except for metal catalysts and isocyanate. Metal catalysts were then added if appropriate and likewise incorporated by stirring. The isocyanate was weighed out separately and then added to the polyol component. The mixture was mixed until the reaction began, and was then poured into a metal box lined with plastic film. The total size of the batch was in each case 1800 g. The foam completed its reaction overnight and was separated by sawing to give test specimens.

(9) TABLE-US-00001 TABLE 1 V1 E1 E2 E3 A-Component: Polyol 1 66.70 80 66.70 66.70 Polyol 2 33.30 20 33.30 33.30 Tegostab B8681 0.50 0.50 0.50 0.50 Dabco 33 LV 0.15 0.15 0.15 0.15 Niax A1 0.05 0.05 0.05 0.05 Diethanolamine (80% in water) 1.49 1.49 1.49 0.75 Ortegol 204 1.50 1.50 1.50 0.75 Kosmos 29 0.30 0.20 0.25 0.18 Water 2.55 2.10 2.10 2.30 TCPP 12.00 P-Polyol 1 12.00 P-Polyol 2 12.00 P-Polyol 3 11.97 B-Component: TDI 100 100 100 100 Index: 107 107 107 107 Mechanics: Density [g/l] 35.5 34.2 36.1 32.6 CLD (40%) [kPa] 3.6 3.5 3.3 4 Ball Rebound [%] 54 52 55 44 CS 22 h/70° C./50% [%] 7 6.4 10.5 11.4 Tensile strength [kPa] 100 86 98 121 Elongation at break [%] 109 109 96 140 Tear resistance [N/mm] 0.58 0.95 0.50 0.67 Air flow [dm.sup.3/s] 0.838 0.786 0.799 0.761 California TB 117 Average char length [mm] 57 71 64 50 Maximum char length [mm] 64 86 66 55 Average afterflame [s] 0 0 0 0 Maximum afterflame [s] 0 0 0 0

(10) The following compounds were used Polyol 1: polyoxypropylene polyoxyethylene polyol based on glycerin; OH number: 35 mg KOH/g; functionality: 2.7 Polyol 2: Graft polyol based on styrene-acrylonitrile; solids content: 45%; polyoxypropyleneoxyethylene polyol based on glycerin; OH number: 20 mg KOH/g; functionality: 2.7 Catalyst system 1: standard catalyst system made of metal catalyst and amine catalyst Catalyst system 2: amine catalysts partially capped by formic acid Isocyanate 1: mixture of toluene 2,4- and 2,6-diisocyanate P-Polyol 1: product of condensation of diphenylchlorophosphate and Polyol 3; OH number: 8 mg KOH/g; P-content 7.9% P-Polyol 2: product of condensation of diphenylchlorophinate and Polyol 4; OH number: 137 mg KOH/g; P-content 7.3% P-Polyol 3: product of condensation of diphenylchlorophosphate and Polyol 4; OH number: 112 mg KOH/g; P-content 7.3% TCPP: Tris(chlorisopropyl)phosphate, commercially available halogen containing flame retardant, P-content 9.46% Polyol 3: propoxylated glycerin; OH number: 400 mg KOH/g. Polyol 4: ethoxylated glycerin; OH number: 535 mg KOH/g.

(11) The following methods were used to determine properties:

(12) Density in kg/m.sup.3: DIN EN ISO 845

(13) Compressive strength in kPa: DIN EN ISO 3386

(14) Rebound resilience in %: DIN EN ISO 8307

(15) Permeability to air in dm.sup.3/s: DIN EN ISO 7231

(16) Flame retardancy: California TB 117 A

(17) The California TB 117 A is a vertical small scale burner test for flexible PU foam. The specimen geometries are 30.5×7.5×1.3 cm. The foam is ignited by a 3.8 cm flame for 12 s.

(18) The test is passed if:

(19) (a) Maximum average burned length of all specimen is smaller than 15 cm

(20) (b) Maximum burned length of each respective specimen is smaller than 20 cm

(21) (c) The average after burning time is not higher than 5 s.

(22) (d) The individual after burning time of each specimen is not higher than 10 s.

(23) (e) The average after glowing time is not higher than 15 s.

(24) (f) The test is performed before and after conditioning for 24 h at 104° C.

(25) The test is passed if for all specimen, the specifications are fulfilled or if 1 specimen does not pass and further 5 specimen pass. Table 1 shows that the halogen-free flexible polyurethane foams of the invention exhibit very good flame retardancy, similar to or better than that of the comparative foams which were prepared using commercially available TCPP with similar or even higher phosphorus content.

(26) It is also found that the mechanical properties of the foams are improved rather than impaired, despite the presence of the flame retardants according to the present invention.

(27) 2.2 Synthesis of a Polyurethane Rigid Foam

(28) A polyurethane rigid foam was prepared as summarized in table 2.

(29) The following formulation was used: 46.5 parts polyester polyol based on terephthalic acid and DEG, OH number: 243 mg KOH/g 25 parts propoxylated sorbitol, OH number: 495 mg KOH/g 6 parts polyethylenglycol, OH number: 190 20 parts flame retardant 2.5 parts stabilizer Niax L-6635 available from company Momentive 0.7 parts potassium acetate 0.4-0.7 parts Niax A1, available from company Momentive 1.3-1.6 parts water 7 parts n-pentane Lupranat M 50, polymeric MDI of company BASF with a NCO-content of 31.5% in an amount to give a NCO-Index of 190.

(30) Polyols, stabilizers, flame retardants, catalysts and blow agents are mixed and stirred. The isocyanate is added subsequently with stirring, and the whole mixture is foamed to a polyurethane hard foam. By adjusting the amount of catalyst the curing time is 45 seconds in each case. The density is adjusted to a constant 45 g/l through the quantity of blowing agent.

(31) TABLE-US-00002 TABLE 2 V2 V3 E4 E5 E6 E7 TCPP 20 DPK 20 P-Polyol 1 20 P-Polyol 4 20 P-Polyol 2 20 P-Polyol 5 20 water 1.4 1.5 1.3 1.6 1.6 1.4 Niax A1 0.60 0.65 0.70 0.50 0.40 0.55 Bolt: hardness after 78 79 — — — 94 3 min (N) Bolt: hardness after 111 107 — — — 128 4 min (N) Bolt: hardness after 132 127 — — — 146 5 min (N) Tack free time (s) 68 73 64 63 63 58 Density (g/L) 45.2 44.3 44.2 44.8 44.8 45.1 Compressive strength 0.21 0.22 — 0.28 0.24 0.23 (N/mm.sup.2) E-module (N/mm.sup.2) 4.9 5.7 — 7.7 7.7 6.3 Flaming test passed yes no yes yes yes yes Flame height (cm) 13.7 17.0 15.0 13.0 14.3 14.8

(32) The following flame retardants were used: P-Polyol 4: product of condensation of diphenylchlorophinate and Polyol 4; OH number: 127 mg KOH/g; P content 6.9% P-Polyol 5: product of condensation of diphenylchlorophinate and Polyol 4; OH number: 75 mg KOH/g; P-content 7.9% DPK: diphenylkresylphosphate

(33) Tack free time: is defined as the period of time between the start of stirring and the time when hardly any tacking effect can be determined when the foam is touched with a rod. Tack free time is an indicator for the effectiveness of the polymerisation.

(34) Bolt: 3, 4, and 5 min after mixing of the components a steel bolt with a spherical cap of 10 mm radius is pressed 10 mm into the formed foam by a tension compression fatigue testing apparatus. The maximum force necessary to achieve this (in N) is an indicator for the degree of curing of the foam. As a measure for the brittleness of the foam the time is determined, when the surface of the foam shows visible fracture zones in the bolt test. The earlier fracture zones appear the higher is the brittleness of the foam.

(35) The flaming test is carried out according to EN ISO 11925-2.

(36) Compressive strength and E-module were determined according to DIN 53421/DIN EN ISO 604.

(37) The examples in Table 2 demonstrate that halogen-free polyurethane rigid foams according to the invention show an excellent flame protection similar or equal to halogen-containing comparative foams. In addition, improved mechanical properties and lower flame height are obtained.

(38) 2.3 Synthesis of a PIR Rigid Foam

(39) A polyisocyanurate rigid foam was prepared as summarized in table 3.

(40) The following formulation was used: 65 parts polyesterpolyol based on phthalic acid anhydride and DEG, OH number 215 mg KOH/g 8 parts polyethylenglykol, OH number 190 mg KOH/g 25 parts flame retardant 2 parts stabilizer Tegostab B 8462 available from company Evonik 0.7 parts potassium formiate 1.4-1.6 parts Niax A1 available from company Momentive 1.5-1.7 parts formic acid, 85% 9 parts n-pentane Lupranat M 50 as polymeric MDI from company BASF with a NCO-content of 31.5% in an amount to give a NCO-Index of 330.

(41) Polyols, stabilizers, flame retardants, catalysts and blow agents are mixed and stirred. The isocyanate is added subsequently with stirring, and the whole mixture is foamed to a polyurethane hard foam. By adjusting the amount of catalyst the curing time is 45 seconds in each case. The density is adjusted to a constant 45 g/l through the quantity of blowing agent.

(42) TABLE-US-00003 TABLE 3 V4 V5 E8 E9 TCPP 20 TEP 20 P-Polyol 2 20 P-Polyol 6 20 Formic acid, 85% 1.5 1.5 1.5 1.7 Niax A1 1.4 1.6 1.6 1.4 Tack free time (s) 67 69 66 67 Density (g/L) 45.4 44.7 44.2 44.8 3-point-bending strength (N/mm.sup.2) 0.24 — 0.37 0.36 Compressive strength (N/mm.sup.2) 0.22 0.23 0.27 0.28 BKZ5 passed yes yes yes yes BKZ5 flaming heigth (cm) 7.0 8.3 7.8 7.3

(43) The following flame retardants were used: P-Polyol 6: product of condensation of diphenylchlorophinate and Polyol 4; OH number: 123 mg KOH/g; P content 7.1%

(44) TEP: Triethylphosphate

(45) BKZ5-Test: In the flaming test according to Swiss norm BKZ/V, the flame height is measured in cm

(46) Bending strength: determined according to DIN 53423. Bending is carried out in the direction of foam development.

(47) The examples in Table 3 demonstrate that halogen-free polyurethane rigid foams according to the invention show an excellent flame protection in combination with improved compressive strength and bending strength.