PHOSPHINATE FLAME RETARDANT AND PROCESS FOR MANUFACTURE THEREOF

Abstract

A phosphinate or a composition of phosphinates obtainable or obtained by reacting at least a phosphinic acid of formula (I) with an oxirane of formula (II):

##STR00001## wherein R1 and R2 are the same or different and independently represent H or a hydrocarbyl radical, with the exception that R1 and R2 may not each be H at the same time and with the hydrocarbyl radical selected from C.sub.1-C.sub.10 alkyl groups, and wherein R3 is an alkylenyl group which is optionally substituted with a heteroatom selected from O, N and S.

The phosphinate or phosphinate composition thus obtained can be used as reactive or additive flame retardant, to manufacture flame-retardant polymers or flame-retardant polymer compositions.

Claims

1-16. (canceled)

17. A phosphinate of the general formula (III-A), (III-B), (IV-A), (IV-B), (V-A), (V-B), (VI-A), (VI-B), (VI-C), or (VI-D): ##STR00016## wherein the phosphinate is obtained by the reaction of at least one phosphinic acid of formula (I) with an oxirane of formula (II): ##STR00017## wherein R1 and R2 are each, independently, H or a hydrocarbyl radical, provided that R1 and R2 may not both be H and the hydrocarbyl radical is selected from C.sub.1-C.sub.10 alkyl; and R3 is an alkylenyl group which is optionally substituted with a heteroatom selected from O, N, and S.

18. The phosphinate of claim 17, wherein each of R1 and R2 is a C.sub.1-C.sub.6 alkyl.

19. The phosphinate of claim 17, wherein one of R1 and R2 is H and the other is a C.sub.1-C.sub.3 alkyl.

20. The phosphinate of claim 17, wherein R3 is a C.sub.1-C.sub.3 alkylenyl.

21. The phosphinate of claim 17, wherein R3 is CH.sub.2.

22. The phosphinate of claim 17, wherein the phosphinate contains a phosphorous content of higher than 12% by weight, based on the total weight of the phosphinate.

23. The phosphinate of claim 17, wherein the phosphinate of the general formula (III-A) or (III-B): ##STR00018##

24. A flame-retardant polymer obtained by reacting monomers and at least one phosphinate of claim 17.

25. A flame-retardant polyurethane obtained by reacting a polyol, an isocyanate, and at least one phosphinate of claim 17.

26. A flame-retardant polyurethane foam obtained by reacting a polyol, an isocyanate, and the phosphinate of claim 17, optionally in the presence of one or more blowing agents, one or more polymerization catalysts, one or more foam stabilizers, and/or other additives.

27. A flame-retardant polymer composition, comprising at least one phosphinate of claim 17, and a polymer, wherein the polymer is a thermoplastic polymer or a duroplastic polymer.

28. A process for the preparation of a phosphinate, comprising the step of reacting at least one phosphinic acid of formula (I) with an oxirane of formula (II): ##STR00019## wherein R1 and R2 are each, independently, H or a hydrocarbyl radical, provided that R1 and R2 may not both be H and the hydrocarbyl radical is selected from C.sub.1-C.sub.10 alkyl; and R3 is an alkylenyl group which is optionally substituted with a heteroatom selected from O, N, and S.

29. The process of claim 28, wherein the phosphinic acid of formula (I) and the oxirane of formula (II) are present in the reaction in a molar ratio of from 2:1 to 1:2.

30. A composition comprising at least one phosphinate of the general formula (III-A), (III-B), (IV-A), (IV-B), (V-A), (V-B), (VI-A), (VI-B), (VI-C), or (VI-D): ##STR00020## wherein the at least one phosphinate is obtained by the reaction of at least one phosphinic acid of formula (I) with an oxirane of formula (II): ##STR00021## wherein R1 and R2 are each, independently, H or a hydrocarbyl radical, provided that R1 and R2 may not both be H and the hydrocarbyl radical is selected from C.sub.1-C.sub.10 alkyl; and R3 is an alkylenyl group which is optionally substituted with a heteroatom selected from O, N, and S.

31. The composition of claim 30, wherein the composition comprises at least one phosphinate where each of R1 and R2 is a C.sub.1-C.sub.6 alkyl.

32. The composition of claim 30, wherein the composition comprises at least one phosphinate where one of R1 and R2 is H and the other is a C.sub.1-C.sub.3 alkyl.

33. The composition of claim 30, wherein the composition comprises at least one phosphinate where R3 is a C.sub.1-C.sub.3 alkylenyl.

34. The composition of claim 30, wherein the composition comprises at least one phosphinate where R3 is CH.sub.2.

35. A flame-retardant polyurethane obtained by reacting a polyol, an isocyanate, and the composition of claim 30.

36. A flame-retardant polyurethane foam obtained by reacting a polyol, an isocyanate, and the composition of claim 30, optionally in the presence of one or more blowing agents, one or more polymerization catalysts, one or more foam stabilizers, and/or other additives.

Description

EXAMPLES

[0085] Hereinafter, the present invention is described in more detail and specifically with reference to the Examples, which however are not intended to limit the present invention.

Methods

[0086] High-performance liquid chromatography coupled with a mass spectrometry (HPLC-MS) was used to determine the molecular composition of the synthesized products in the Synthetic Examples.

[0087] Structural elucidation on identifying regio-isomers was performed via .sup.1H- and .sup.31P-NMR. Separation method for individual phosphinate compounds in the product is preparative column chromatography.

Raw Materials

TABLE-US-00001 Diethylphosphinic acid (DEPS) CAS: 813-76-3 Mw = 122.1 g/mol Ethylphosphinic acid (EPOS) CAS: 4363-06-8 Mw = 94.1 g/mol ()-Glycidol, 96 wt. % CAS: 556-52-5 Mw = 74.1 g/mol

Synthetic Examples

Generic Synthetic Procedure: {Phosphinic Acid+Glycidol}

[0088] 100 g of a phosphinic acid is placed in a 500 mL five-necked flask with a dropping funnel under an argon atmosphere. The phosphinic acid is heated to [90-150] C. while stirring and [60-1000]g glycidol is added via dropping funnel over the course of eight hours. The mixture is then stirred at [100-180] C. for a further [1-10]h. While the Synthetic Examples 1-3 below used DEPS and EPOS as the only two phosphonic acid to react with glycidol, the Applicant has noted that other phosphonic acid and other oxiranes are also applicable in this procedure under similar reaction conditions.

[0089] Main products of the Synthetic Examples 1 & 2 and their structures: [0090] (1) DEPS-Glycidol I: isomeric mixture as identified below:

##STR00008## [0091] (2) DEPS-Glycidol II: isomeric mixture with main isomers identified below:

##STR00009## [0092] (3) DEPS-Glycidol III: isomeric mixture with main isomers identified below:

##STR00010## [0093] (4) DEPS-Glycidol IV: isomeric mixture with main isomers as identified below:

##STR00011##

[0094] Main products of the Synthetic Examples 3 and their structures: [0095] (1) EPOS-Glycidol I: isomeric mixture as identified below:

##STR00012## [0096] (2) EPOS-Glycidol II: isomeric mixture with main isomers identified below:

##STR00013## [0097] (3) EPOS-Glycidol III: isomeric mixture with main isomers identified below:

##STR00014## [0098] (4) EPOS-Glycidol IV: isomeric mixture with main isomers as identified below:

##STR00015##

Synthetic Example 1: FR1 {DEPS-Glycidol}

[0099] 122.1 g of diethylphosphinic acid was placed in a 500 mL five-necked flask with a dropping funnel under an argon atmosphere. The diethylphosphinic acid was heated to 120 C. while stirring and 115.7 g glycidol was added via dropping funnel over the course of eight hours. The mixture was then stirred at 150 C. for a further six hours. The light brown viscous product was analyzed by means of HPLC-MS, which revealed the following product composition of our FR1: [0100] DEPS-Glycidol I: 28% [0101] DEPS-Glycidol II: 18% [0102] DEPS-Glycidol III: 36% [0103] DEPS-Glycidol IV: 16% [0104] Diglycerol: 2%

[0105] The product had an acid value of <1 mg KOH/g, an OH value of 614 mg KOH/g, and a phosphorous content of 13.3 wt %.

[0106] .sup.31P-NMR (DMSO-d6) analysis of the product showed multiple signals in the range of 62.4-61.4 ppm>98 mol %.

Synthetic Example 2: {DEPS-Glycidol}

[0107] 122.1 g of diethylphosphinic acid was placed in a 500 mL five-necked flask with a dropping funnel under an argon atmosphere. The diethylphosphinic acid was heated to 65 C. while stirring and 123.5 g glycidol was added via dropping funnel over the course of three hours. The mixture was then stirred at 120 C. for a further 20 hours. The light brown viscous product was analyzed analytically by means of HPLC-MS, which revealed the following product composition: [0108] DEPS-Glycidol I: 15% [0109] DEPS-Glycidol II: 34% [0110] DEPS-Glycidol III: 25% [0111] DEPS-Glycidol IV: 22% [0112] Diglycerol: 4%

[0113] The product had an acid value of 2.4 mg KOH/g, an OH value of 631 mg KOH/g, and a phosphorous content of 12.9 wt %.

[0114] .sup.31P-NMR (DMSO-d6) analysis of the product showed multiple signals in the range of 62.4-61.4 ppm>98 mol %.

Synthetic Example 3: FR2 {EPOS-Glycidol}

[0115] 119.6 g of ethylphosphinic acid was placed in a 500 mL five-necked flask with a dropping funnel under an argon atmosphere. The ethylphosphinic acid was heated to 100 C. while stirring and 161 g glycidol was added via dropping funnel over the course of 2 hours. The mixture was then stirred at 150 C. for a further 8 hours. The colorless liquid-clear product was analyzed analytically by means of HPLC-MS, which revealed the following product composition: [0116] EPOS-Glycidol I: 16% [0117] EPOS-Glycidol II: 30% [0118] EPOS-Glycidol III: 28% [0119] EPOS-Glycidol IV: 23% [0120] Diglycerol: 3%

[0121] It was found that the EPOS-Glycidol product in this synthetic example has similar regioisomerism as the DEPS-Glycidol products of synthetic examples 1 and 2. The product had an acid value of <1 mg KOH/g and an OH value of 700 mg KOH/g, and a phosphorus content of 14.1 wt %.

[0122] .sup.31P-NMR (DMSO-d6) analysis of the product showed multiple signals in the range of 46.0-42.0 ppm>95 mol %.

Application Examples

1. Components Used:

Flame Retardant:

[0123] FR-1: product of Synthetic Example 1 [0124] FR-2: product of Synthetic Example 3 [0125] Ref-1: Fyrol PCF from ICL Industrial Products, TCPP (tris (1-chloro-2-propyl) phosphate), a halogenated phosphate ester [0126] Ref-2: Exolit OP 550 from Clariant International Ltd, a non-halogenated, polymeric phosphorus polyol specifically designed for flexible polyurethane foams, which is a phosphate ester with hydroxyalkyl groups. [0127] Ref-3: Exolit OP 560 from Clariant International Ltd., a non-halogenated polymeric phosphorous polyol specifically designed for flexible polyurethane foams, which is a phosphonate ester with hydroxyalkyl groups.

Polyol:

[0128] Polyether polyol (P1): Arcol 1104 or 1108 from Covestro AG, a medium molecular weight polyoxypropylene triol with an OH number of 56 mg KOH/g [0129] Polyester polyol (P2): Desmophen 60WB01 from Covestro AG, a partly branched polyester polyol based on adipic acid, diethylene glycol and trimethylol propane, with an OH number of 60 mg KOH/g

Polymerization Catalyst:

[0130] Cat 1: Kosmos EF from Evonik Industries, a stannous catalyst [0131] Cat 2: Kosmos 29 from Evonik Industries, a stannous octoate catalyst [0132] Cat 3: Niax A1 from Momentive Performance Materials Inc., an amine catalyst based on bis(2-dimethylaminoethyl)ether [0133] Cat 4: Tegoamin 33 from Evonik Industries, an amine catalyst based on triethylenediamine [0134] Cat 5: JEFFCAT ZF-10 from Huntsman, an amine catalyst based on N,N,N-trimethyl-N-hydroxyethylbisaminoethylether [0135] Cat 6: Tegoamin E10 from Evonik Industries, an amine catalyst based on 1,4-dimethylpiperazine [0136] Cat 7: Niax A30 from Momentive Performance Materials Inc., an amine catalyst based on bis(2-dimethylaminoethyl) ether

Foam Stabilizer:

[0137] S1: Tegostab B 8232 from Evonik Industries, a silicone surfactant [0138] S2: Tegostab B 8244 from Evonik Industries, a silicone surfactant [0139] S3: Tegostab B 8235 from Evonik Industries, a silicone surfactant

TDI (Tolyl Diisocyanate):

[0140] T80: Desmodur T80 from Covestro AG, 2,4- and 2,6-toluene diisocyanate, 80/20 mixture of isomers [0141] T65: Desmodur T65 from Covestro AG, 2,4- and 2,6-toluene diisocyanate, 65/35 mixture of isomers

2. Hydrolytic Stability Test

[0142] Hydrolytic stability of different flame retardants was determined by measuring the acid value of blends made of polyol, flame retardant and water over time and during storage at an elevated temperature. For this purpose, 90 g of polyol, 9 g of flame retardant (10 wt.-%) and 4.5 g of water (5 wt.-%) were homogenized by stirring at 1500 rpm for 2 minutes. The acid value was then determined using a 3:1 (v/v) isopropanol/water mixture as solvent and 0.1 N NaOH (aq.) solution as titration agent. The samples were then stored at 40 C. and the acid values determined after 11, 17 and 28 days. Samples were homogenized before analysis by stirring at 1500 rpm for 2 minutes. The acid value development of polyol-water blends without flame retardant addition was also determined after 11 and 28 days, respectively, as shown in the table below.

TABLE-US-00002 TABLE 1 Hydrolytic stability test: Evolution of the acid value of mixtures of polyols with 10%(m/m) of flame retardant and 5%(m/m) of water during storage at 40 C. Acid value (mg KOH/g) Polyol Flame retardant 11 d 17 d 28 d Polyether P1 0 0.1 blend P1 FR-1 0.1 0.1 0.1 P1 Ref-2 42.8 45.7 47.2 P1 Ref-3 16.4 16.5 16.6 Polyester P2 1.3 1.9 blend P2 FR-1 1.3 1.4 1.9 P2 Ref-2 89.8 93.0 94.7 P2 Ref-3 71.9 81.1 84.1

[0143] Regardless of the polyol type and compared to the flame-retardant-free reference, the inventive example FR-1 did not cause a notable increase of acid value in their polyol blends, during and after the entire 28 days of storage under 40 C. This indicates a high hydrolytic stability of FR-1 during storage in the polyol blend, namely zero to negligible hydrolysis of the FR-1. In comparison, for both polyol types, the acid value of polyol blends containing a phosphate Ref-2 or a phosphonate Ref-3 significantly increased after merely 11 days under the same storage condition, which can only be explained by hydrolysis of Ref-2 or Ref-3, respectively.

3. Flexible Polyurethane (PUR) Foam Formulations with Performance Testing

[0144] Stannous catalysts, polyol, flame retardant, water, foam stabilizer and amine catalysts were weighed into a dry beaker in that order and premixed for 60 seconds at 500 rpm (for polyether polyol formulations) or 1000 rpm (for polyester polyol formulations), respectively. After addition of TDI, the mixtures were stirred at 2500 rpm for 7 seconds. The resulting mass was rapidly poured into a paper-lined box mold (25*26*26 cm). Rise time and further observations were noted during the foaming process. The foams were cured at room temperature for approximately 16 hours before cutting and collected in each comparative (C1-C7) or inventive (I1-I3) example for further evaluation.

[0145] The selection of polymerization catalyst, foam stabilizer and TDI in each foam example was made based on existing empirical guidance for optimal foamability in each case, with details listed below in Table 2.

TABLE-US-00003 TABLE 2 Polyol, Flame Retardant, Catalyst, Foam Stabilizer and TDI used in each foam example Components Flame Polymerization Catalyst Foam TDI Example Polyol Ret. Catalyst(s) wt ratio Stabilizer TDI(s) wt ratio C1 P1 Cat 2 Cat 3 Cat 4 (3:2:4) S1 T80 C2 P1 Ref-1 Cat 2 Cat 3 Cat 4 (2:1:2) S1 T80 C3 P1 Ref-1 Cat 2 Cat 3 Cat 4 (1.3:1:2) S1 T80 C4 P1 Ref-2 Cat 2 Cat 3 Cat 4 (3:2:4) S1 T80 C5 P2 Cat 6 Cat 7 (3:2) S3 T80 C6 P2 Ref-1 Cat 6 Cat 7 (1:1) S3 T80 C7 P2 Ref-2 Cat 1 Cat 6 (4:9) S3 T80 T65 (41.4:10.4) I1 P1 FR-1 Cat 1 S2 T80 I2 P1 FR-2 Cat 1 Cat 5 (3:2) S1 T80 I3 P2 FR-1 Cat 1 Cat 6 Cat 7 (2:5:8) S3 T65

[0146] Each of the PUR foam example was then evaluated for flame retardancy and emission performance, as explained below.

Evaluation of Flame Retardancy

[0147] The efficiency of the flame retardants was evaluated by testing the burning behavior of flexible polyurethane foam samples with a target density of 30 kg/m.sup.3, containing the flame retardants in the horizontal burn test, as described in the Federal Motor Vehicle Safety Standard 302 (FMVSS 302). According to this standard, samples are given the highest classification (SE, self-extinguishing) if the flame does not travel beyond a 38 mm mark on the specimen but extinguishes within this distance. Lower classifications include SE/NBR (self-extinguishing/no burn rate), SE/B (self-extinguishing/burn rate) and B (burn rate). Five sample specimens were cut from each foam and submitted to the test. The lowest-rated specimen determined the overall classification for the foam.

Evaluation of Emission Performance

[0148] Low emissions from materials are particularly important in interior automotive applications. They can be classified into two types: semi-volatile condensable emissions (FOG) and volatile organic compounds (VOC). The name FOG emissions stems from the fogging effect they can have on cold surfaces such as car windshields. They can be quantified according to DIN 75201 B: A sample is heated to 100 C. for 16 h in a specialized device, while semi-volatile components of the emissions are condensed on a cooled surface and quantified gravimetrically. VOC emissions can be quantified by thermodesorption analysis according to the automotive standard VDA 278. A sample in a thermodesorption tube is heated to 90 C. for 30 min, and condensates are collected in a cooling trap before being identified and quantified via GC/MS against an external standard like toluene. The emission performance of the new flame retardant described herein was evaluated by determining both FOG and VOC emissions according to these procedures.

[0149] The flame retardancy and emission performance of tested foam examples are compared below, separately listed by the polyol type in the foam.

TABLE-US-00004 TABLE 3 Performance data of flexible polyurethane polyether (P1) foam formulations Example Component* C1 C2 C3 C4 I1 I2 P1 100 100 100 100 100 100 Ref-1 0 12 8 0 0 0 Ref-2 0 0 0 4 0 0 FR-1 0 0 0 0 4 0 FR-2 0 0 0 0 0 4 Catalyst 0.45 0.50 0.43 0.45 0.17 0.5 Water 3.5 4.0 3.2 3.5 3.3 3.3 Foam Stabilizer 1.3 1.3 1.3 1.3 1.3 0.7 TDI 43.7 48.4 40.3 44.5 46.45 46.87 Density 32.1 29.8 32.5 29.8 28.9 29.6 [kg/m.sup.3] FMVSS 302 B SE SE/ SE SE SE rating NBR Fogging [mg/g] n.d..sup. 26.2 n.d. 2.0 0.3 0.3 VDA 278 n.d. 5787 n.d. 547 52 103 [ppm] *Amounts of all components are given in parts per 100 parts of polyol (php). .sup.not determined

[0150] As shown in the performance data listed in Table 3, comparative example C1 (polyether polyurethane foam without flame retardant additive) does not meet the required flame retardancy standard. With 12 php of halogenated reference flame retardant TCPP (Ref-1), the comparative example C2 provides a polyether polyurethane foam which meets required flame retardancy standards but shows very bad emission properties, as reflected in the associated fogging and VDA 278 parameters. In an attempt to reduce undesired emission in TCPP-incorporated PUR foam samples, comparative example C3 has reduced the TCPP content to 8 php but failed to achieve the required flame retardancy rating.

[0151] Comparative example C4 is a polyether polyurethane foam with 4 php of reactive non-halogenated reference flame retardant Exolit OP 550 (Ref-2), which meets required flame retardancy standards, gives lower semi-volatile condensable emissions (i.e. fogging) compared to C2 but still higher VOC (i.e. VDA 278) than desired.

[0152] The inventive example I1, a polyether polyurethane foam with 4 php of reactive non-halogenated inventive flame retardant (FR-1), not only meets required flame retardancy standards but also features least emission in both semi-volatile condensable emissions and VOC measurements.

[0153] The inventive example I2, a polyether polyurethane foam with 4 php of reactive non-halogenated inventive flame retardant (FR-2), is equally excellent as I1, in flame retardancy rating and emission properties.

TABLE-US-00005 TABLE 4 Performance data of flexible polyurethane polyester (P2) foam formulations Example Component C5 C6 I3 P2 100 100 100 Ref-1 0 8 0 FR-1 0 0 6.5 Catalyst 1.0 0.8 0.75 Water 4.0 4.0 4.1 Stab 1.2 1.2 1.2 TDI 55.4 49.9 52.7 Density [kg/m.sup.3] 30.0 32.0 29.5 FMVSS 302 rating B SE SE Fogging [mg/g] n.d. 4.52 0.25 VDA 278 [ppm] n.d. 3049 180

[0154] As shown in the performance data listed in Table 3, comparative example C5 (polyurethane polyester foam) without flame retardant does not meet the required flame retardancy standard.

[0155] With 8 php of halogenated reference flame retardant TCPP (Ref-1), the comparative example C6 provides a polyurethane polyester foam which meets required flame retardancy standards but shows very bad emission properties, as reflected in the associated fogging data and especially the VDA 278 measurement.

[0156] Advantageously, the inventive example I3, a polyurethane polyester foam with 6.5 php of reactive non-halogenated inventive flame retardant (FR-1), not only meets required flame retardancy standards but also gives the minimal quantity in both semi-volatile condensable emissions and VOC measurements.

[0157] Summarizing from these experimental data, the technical benefits of the inventive phosphinate flame retardants are not limited to the hydrolytic stability, compatibility with polyol system for polymer processing, but also extended to providing flame-retardant PUR foams with excellent flame retardancy and minimal emission upon use. It was further noted that, the inventive flame retardants FR-1 and FR-2 showed excellent compatibility with each polyol tested and stayed in solution in liquid form on the shelf over 28 days.