PHOSPHINATE AS FLAME-PROOFING ADDITIVE FOR PUR/PIR HARD FOAM MATERIAL

Abstract

The invention relates to flame-proofed polyurethane hard foam material or polyurethane/polyisocyanurate hard foam material (designated below individually or jointly also as “PUR/PIR hard foam material”) comprising phosphinates (also hypophosphite), and to a method for producing PUR/PIR hard foam materials through the implementation of a reaction mixture containing A1 an isocyanate-reactive component, A2 propellant, A3 catalyst, A4 optionally additive, A5 flame-proofing agent, B an isocyanate component, characterised in that the flame-proofing agent A5 contains a phosphine according to the formula (I)M[(R).sub.2PO.sub.2].sub.n, where R=in each case stands for H, C1- to C4-(hydroxy-)alkyl group or benzyl group, M=an element of the main groups 1 to 3, wherein hydrogen is excepted, and n=the number of the main group of M, and the proportion of the phosphine according to the formula (I) is 0.1 to 15 wt %, based on the total mass of components A1 to A5.

Claims

1. A process for producing rigid PUR/PIR foams, comprising reacting a reaction mixture comprising: A1 an isocyanate-reactive component; A2 blowing agent; A3 catalyst; A4 optionally additive; A5 flame retardant; and B an isocyanate component, wherein the flame retardant A5 comprises a phosphinate of formula (I)
M[(R).sub.2PO.sub.2].sub.n  (I), wherein each R independently represents H, C1- to C4-(hydroxy)alkyl or benzyl, M is an element from main groups 1 to 3, with the exception of hydrogen, and n is the number of the main group of M, and wherein the phosphinate of formula (I) is present in an amount of 0.1% to 15% by weight, based on the total mass of components A1 to A5.

2. The process as claimed in claim 1, wherein the isocyanate-reactive component A1 comprises a polyester polyol.

3. The process as claimed in claim 1, wherein the isocyanate-reactive component A1 comprises a polyester polyol having an equivalent weight of 50 g/mol to 2000 g/mol.

4. The process as claimed in claim 1, wherein the phosphinate of formula (I) is present in an amount of 1.0% by weight to 50.0% by weight based on the total mass of the flame retardant A5.

5. The process as claimed in claim 1, wherein the phosphinate of formula (I) is present in an amount of 0.5% by weight to 15.0% by weight, based on the total mass of the components A1 to A5.

6. The process as claimed in claim 1, wherein the flame retardant A5 contains no halogen-containing flame retardant.

7. The process as claimed in claim 1, wherein M is an element from main group 1 or 2.

8. The process as claimed in claim 1, wherein M is selected from sodium, potassium, magnesium, calcium and aluminum.

9. The process as claimed in claim 1, wherein the flame retardant A5 further comprises diphenylcresyl phosphate, triethyl phosphate, bisphenol A bis(diphenylphosphate) or a mixture thereof.

10. The process as claimed in claim 1 wherein at least one R is hydrogen or C1-C4-alkyl.

11. The process as claimed in claim 1, wherein the phosphinate of formula (I) has a particle diameter d.sub.50 of less than 50.0 μm.

12. The process as claimed in claim 1, wherein the isocyanate component B comprises MDI, polymeric MDI, TDI, or a mixture thereof.

13. A rigid PUR/PIR foam obtained by the process as claimed in claim 1.

14. An insulation material comprising the rigid PUR/PIR foams as claimed in claim 13.

15. A reaction mixture for producing rigid PUR/PIR foams, comprising: A1 an isocyanate-reactive component A2 blowing agent A3 catalyst A4 optionally additive A5 flame retardant, wherein the flame retardant A5 comprises a phosphinate of formula (I)
M[(R).sub.2PO.sub.2].sub.2  (I), wherein each R independently represents H, C1-to C4-(hydroxy)alkyl or benzyl, M is an element from main groups 1 to 3, with the exception of hydrogen, and n is the number of the main group of M, and wherein the phosphinate of formula (I) is present in an amount of 0.1 to 15% by weight based on the total mass of components A1 to A5.

Description

EXAMPLES

[0152]

TABLE-US-00001 A1-1 Polyester polyol composed of terephthalic acid, adipic acid, ethylene glycol and diethylene glycol having an equivalent weight of 384 g/mol A1-2 Polyester polyol composed of phthalic anhydride, adipic acid, ethylene glycol and diethylene glycol having an equivalent weight of 267 g/mol A1-3 Polyester polyol composed of adipic acid, ethylene glycol and diethylene glycol having an equivalent weight of 1000 g/mol A1-4 Reaction product of trimethylolpropane with 9.3 equivalents of ethylene oxide having an equivalent weight of 225 g/mol A1-5 Polyester polyol composed of phthalic anhydride and diethyleneglycol having an equivalent weight of 240 g/mol A1-6 Sugar ester DUB SE 11S (Oleochem) A1-7 Polyglycerol polyricinoleate (Paalsgard ® PGPR 4150, Oleochem) A2-1 n-Pentane A2-2 Water A3-1 46% by weight solution of a mixture (2.2:1 mol/mol) of potassium acetate and 1,2-bis[2-(2-hydroxyethoxy)ethyl] phthalate in diethylene glycol A3-2 Mixture of 80% by weight of potassium 2-ethylhexanoate, 13% by weight of potassium acetate and 7% by weight of pentamethyldiethylenetriamine A4-1 Polyether-modified silicone (Tegostab ® B8443, Evonik) A5-1 Triethyl phosphate (Levagard ® TEP, Lanxess) A5-2 Bisphenol A bis(diphenyl phosphate) (Fyroflex ® BDP, ICL Industrial Products) A5-3 Diphenyl cresyl phosphate A5-4 Al[(C.sub.2H.sub.5).sub.2PO.sub.2].sub.3 with a particle size d.sup.50 = 20 μm Exolit ® OP 1230, Clariant) A5-5 Al[(C.sub.2H.sub.5).sub.2PO.sub.2].sub.3 with a particle size d.sup.50 = 4 μm (Exolit ® OP 935, Clariant) A5-6 Na[H.sub.2PO.sub.2] (Sigma-Aldrich) A5-7 Aluminum hydroxide (Martinal ® OL-104C, Martinswerk GmbH) A5-8 Magnesium hydroxide (Vertex ® 100, J. M. Huber Corporation) A5-9 Ammonium polyphosphate Exolit ® AP422 (Clariant) A5-10 Sepiolite Adins Clay NC (Tolsa) A5-11 Sepiolite Adins Clay 20 (Tolsa) A5-12 Tris(2-chloroisopropyl) phosphate B-1 Polymeric MDI with a viscosity of 0.7 Pas (at 25° C.) and an NCO content of 31.5% by weight

[0153] Production and Testing of Rigid PUR/PIR Foams

[0154] The flame spread of the rigid PUR/PIR foams was measured by edge flaming with the small burner test according to DIN 4102-1 (May 1998) on a sample having dimensions of 18 cm×9 cm×2 cm.

[0155] The measurement of the MARHE value (Maximum Average Rate of Heat Emission) was measured according to ISO standard 5660-1 (March 2015) with a “cone calorimeter”. The test specimens measuring 1 dm×1 dm×0.3 dm are irradiated for 20 minutes by a heat radiator having an irradiance of 50 kW/m.sup.2. The determined MARHE value indicates the maximum value of the heat emission rate averaged over the test time.

[0156] The compressive strength of the rigid PUR/PIR foams was determined according to DIN EN 826 (May 2013) on test specimens having dimensions of 50 mm×50 mm×50 mm.

[0157] The compressive strength of the test specimens was measured in the foaming direction and perpendicular to the foaming direction.

[0158] Measurement of apparent density was performed according to DIN EN ISO 845 (October 2009).

[0159] Based on the polyol components rigid PUR/PIR foams were produced in the laboratory by mixing 0.3 dm.sup.3 of a reaction mixture in a paper cup. To this end the flame retardant, the foam stabilizer, catalysts and n-pentane as the blowing agent were added to the respective polyol component and the mixture was briefly stirred. The obtained mixture was mixed with the isocyanate and the reaction mixture was poured into a paper mold (3×3×1 dm.sup.3) and reacted therein. The exact formulations of the individual experiments are reported in Tables 1 and 2, as are the results of the physical measurements on the samples obtained.

TABLE-US-00002 TABLE 1 Examples 1* 2 3 4 5 6* 7* A1-1 parts by 64 64 64 64 64 A1-2 parts by 41 41 A1-3 parts by 14.9 14.9 A1-4 parts by 6.4 6.4 A2-1 parts by 15 15 15 15 15 16 16 A2-2 parts by 1 1 A3-1 parts by 7 7 7 7 7 12.4 12.4 A4-1 parts by 4 4 4 4 4 5 5 A5-1 parts by 12.5 10 10 10 10 A5-2 parts by 12.5 10 10 10 10 A5-3 parts by 19.2 19.2 A5-4 parts by 5 30 A5-5 parts by 5 12 A5-6 parts by 12 A5-7 parts by 30 B-1 parts by 126 126 126 126 126 174.9 174.9 Index 320 320 320 320 320 320 320 Properties Apparent density kg/m.sup.3 32 33 33 35 33 34 33 from core of Compressive MPa 0.08 0.10 0.13 0.10 0.11 0.08 0.05 strength in weakest direction Anisotropy 2.9 2.3 1.3 2.0 1.9 1.9 2.4 Cream time s 10 10 8 8 12 22 25 Fiber time s 50 70 80 40 100 130 130 Rise time s 50 55 50 40 100 100 100 Vertical flame cm 12 11 11 9 11 16 17 spread *comparative example

[0160] Table 1 shows the use of phosphinate of formula (I) as a constituent of a flame retardant mixture compared to flame retardant mixtures which are representative of the prior art. The rigid PUR/PIR foams of Examples 2 to 5 exhibit a lower flame spread than the rigid PUR/PIR foam of comparative example 1 and also an improvement in compressive strength and anisotropy, wherein example 3 in particular exhibits a marked improvement in anisotropy. Also compared to a flame retardant mixture containing a solid as the flame retardant (comparative example 7) example 6 containing a phosphinate of formula (I) exhibits a lower flame spread, anisotropy and an improved compressive strength. Examples 2 to 5 in comparison with example 6 further show that the use of an inventive amount of the phosphinate of formula (I) results in an improved flame retardancy and compressive strength.

[0161] Table 2 shows the use of phosphinates of formula (I) as the sole flame retardant in the production of rigid PUR/PIR foams compared to a flame retardant employed in the form of a solid. The rigid PUR/PIR foam of Example 8 exhibits better flame retardancy than comparative example 9 on account of a lower MARHE value.

TABLE-US-00003 TABLE 2 8 9* Examples A1-5 parts by 100 100 A2-1 parts by 20.3 20.3 A3-2 parts by 6.8 6.8 A4-1 parts by 2.5 2.5 A5-4 parts by 10 A5-8 parts by 10 B-1 parts by 126.7 126.7 Index 250 250 Properties Apparent density from core of Kg/m.sup.3 29.0 30.8 molding MARHE kW/m.sup.2 173 216 Heat emission (peak) .sup.1) kW/m.sup.2 204 260 *comparative example .sup.1) highest measured value of heat emission when measuring heat emission over 600 seconds according to ISO standard 5660-1 (March 2015).

[0162] Table 2 shows the comparison of a rigid PUR/PIR foam comprising a phosphinate of formula (I) as the sole flame retardant (example 8) with a rigid PUR/PIR foam containing a noninventive flame retardant in the form of a solid (example 9). Both the MARHE value and the peak of the heat emission are significantly lower when the inventive flame retardant is used (example 8) than when the noninventive flame retardant is used (example 9).

TABLE-US-00004 TABLE 3 10 11 12 Examples A1-2 parts by wt. 32.1 32.1 32.1 A1-3 parts by wt. 11.7 11.7 11.7 A1-6 parts by wt. 5.0 5.0 A1-7 parts by wt. 5.0 A2-1 parts by wt. 11.2 11.2 12.2 A3-1 parts by wt. 7.2 7.2 7.2 A5-3 parts by wt. 15.0 15.0 15.0 A5-5 parts by wt. 5.0 5.0 5.0 A5-9 parts by wt. 25.0 25.0 25.0 A5-10 parts by wt. 2.0 2.0 A5-11 parts by wt. 2.0 B-1 parts by wt. 122.0 122.0 147.1 Index 320 320 320 Properties Cream time s 30 30 30 Fiber time s 240 180 180 Rise time s 120 120 110 Apparent density from core kg/m.sup.3 42 42 42 of molding Open-cell content % 9 8 10 Compressive strength in MPa 0.10 0.11 0.11 weakest direction Vertical flame spread cm 13 13 12 MARHE kW/m.sup.2 75 69 62 Heat emission (peak) .sup.1) kW/m.sup.2 118 113 100 .sup.1) highest measured value of heat emission when measuring heat emission over 600 seconds according to ISO standard 5660-1 (March 2015).

[0163] Table 3 shows that rigid PUR/PIR foams containing isocyanate-reactive components produced with bio-based starting materials likewise have good flame retardancy properties with the inventive flame retardant.

TABLE-US-00005 TABLE 4 13* 14 Examples A1-1 parts by wt. 64 64 A1-4 parts by wt. 5 5 A2-1 parts by wt. 15 15 A3-1 parts by wt. 7 7 A4-1 parts by wt. 4 4 A5-1 parts by wt. 5 5 A5-2 parts by wt. 15 A5-5 parts by wt. 5 A5-12 parts by wt. 20 B-1 parts by wt. 173 173 Index 320 320 Properties Chlorine content from flame % by 2.2 retardants in A + B weight Cream time s 18 20 Rise time s 40 45 Apparent density from core of kg/m.sup.3 40 38 molding Open-cell content % 18 8 Parallel to direction of rise MPa 0.15 0.33 Perpendicular to direction of rise MPa 0.10 0.11 Vertical flame spread cm 8 9 MARHE kW/m.sup.2 26 29 Heat emission (peak) .sup.1) kW/m.sup.2 132 138 *comparative example .sup.1) highest measured value of heat emission when measuring heat emission over 600 seconds according to ISO standard 5660-1 (March 2015).

[0164] The comparison between example 13, a formulation with a halogenated flame retardant, and example 14 shows that the compressive strength of the rigid PUR/PIR foam comprising the inventive flame retardant is improved compared to the rigid PUR/PIR foam comprising a halogenated flame retardant while simultaneously obtaining good flame retardancy properties.