FLAME-RETARDANT POLYURETHANE RIGID FOAMS

Abstract

A process for producing rigid PUR/PIR foams via the reaction of a reaction mixture comprising A1 an isocyanate-reactive component, A2 a flame retardant, A3 a blowing agent, A4 a catalyst, and A5 optionally auxiliaries and additives with B an organic polyisocyanate component. Component A1 comprises a diurethane diol A1.1 and a compound A1.2 selected from the group consisting of polyether polyol, polyester polyol, polyether carbonate polyol, and polyether ester polyol. Also disclosed is a rigid PUR/PIR foam, an insulating material, a composite element, and a mixture.

Claims

1. A process for producing rigid PUR/PIR foams via the reaction of a reaction mixture comprising A1 an isocyanate-reactive component A2 a flame retardant A3 a blowing agent A4 a catalyst, and A5 optionally auxiliaries and additives with B an organic polyisocyanate component wherein component A1 comprises a diurethane diol A1.1 and a compound A1.2 selected from the group consisting of polyether polyol, polyester polyol, polyether carbonate polyol and polyether ester polyol.

2. The process as claimed in claim 1, wherein the isocyanate-reactive component A1 comprises the compound A1.2 and the compound A1.2 has a hydroxyl number of 100 to 550 mg KOH/g.

3. The process as claimed in claim 1, wherein the isocyanate-reactive component A1 a comprises the compound A1.2 and the compound A1.2 has an OH functionality of 1.5 to 4.0.

4. The process as claimed in claim 1, wherein the compound A1.2 is a polyester polyol or a polyether polyol.

5. The process as claimed in claim 1, wherein the compound A1.2 is a polyester polyol obtainable from the reaction of aliphatic and/or aromatic dicarboxylic acid with at least one aliphatic diol.

6. The process as claimed in claim 1, wherein the diurethane diol A1.1 has a structure of formula (II) ##STR00004## wherein R.sup.1 is linear or branched C.sub.2-- to C.sub.24-alkylene which may optionally be interrupted by heteroatoms and may optionally be substituted, R.sup.2 is linear or branched C.sub.2- to C.sub.24-alkylene, C.sub.3- to C.sub.24-cycloalkylene, C.sub.4- to C.sub.24-arylene, C.sub.5- to C.sub.24-aralkylene, C.sub.2- to C.sub.24-alkenylene, or C.sub.2- to C.sub.24-alkynylene, each of which may optionally be interrupted by heteroatoms and/or each of which may optionally be substituted by alkyl, aryl and/or hydroxyl, R.sup.3 is H, linear or branched C.sub.1- to C.sub.24-alkyl, C.sub.3- to C.sub.24-cycloalkyl, C.sub.4- to C.sub.24-aryl, C.sub.5- to C.sub.24-aralkyl, C.sub.2- to C.sub.24-alkenyl, or C.sub.2- to C.sub.24-alkynyl, each of which may optionally be interrupted by heteroatoms and/or each of which may optionally be substituted by alkyl, aryl and/or hydroxyl, R.sup.4 is H, linear or branched C.sub.1- to C.sub.24-alkyl, C.sub.3- to C.sub.24-cycloalkyl, C.sub.4- to C.sub.24-aryl, C.sub.5- to C.sub.24-aralkyl, C.sub.2- to C.sub.24-alkenyl, or C.sub.2- to C.sub.24-alkynyl, each of which may optionally be interrupted by heteroatoms and/or each of which may optionally be substituted by alkyl, aryl and/or hydroxyl, R.sup.5 is linear or branched C.sub.2- to C.sub.24-alkylene which may optionally be interrupted by heteroatoms and may optionally be substituted, and wherein R.sup.1 to R.sup.5 may be identical or different from one another.

7. The process as claimed in claim 1, wherein the diurethane diol A1.1 is obtained from the reaction between cyclic ethylene carbonate and/or cyclic propylene carbonate with at least one compound selected from the group consisting of propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine, hexane-1,6-diamine, isophoronediamine, 2-methylpentane-1,5-diamine, all isomers of methylenedicyclohexyl-4,4-diamine, all isomers of 1-methyl-2,4-diaminocyclohexane and of 1-methyl-2,6-diaminocyclohexane and mixtures thereof.

8. The process as claimed in claim 1, wherein the proportion of diurethane diol A1.1 is 0.1% to 35.0% by weight based on the sum total of the masses of components A1.1 and A1.2.

9. The process as claimed in claim 1, wherein the isocyanate index is 100 to 500.

10. The process as claimed in claim 1, wherein the flame retardant A2 is in a proportion of 2.0% by weight to 30.0% by weight, based on the weight of components A1 to A5.

11. The process as claimed in claim 1, wherein the polyisocyanate component B used is at least one compound selected from the group consisting of tolylene 2,4- and 2,6-diisocyanate, diphenylmethane 4,4- and 2,4- and 2,2-diisocyanate and polyphenylpolymethylene polyisocyanate (polycyclic MDI).

12. A rigid PUR/PIR foam obtainable by a process as claimed in claim 1.

13. The rigid PUR/PIR foam as claimed in claim 12, wherein an apparent density of the rigid PUR/PIR foam is 25.0 to 300.0 kg/m.sup.3.

14. An insulating material or composite element with flexible or non-flexible outer layers comprising the rigid PUR/PIR foam as claimed in claim 12.

15. A mixture comprising a diurethane diol A1.1 and a compound A1.2, wherein the compound A1.2 is selected from the group consisting of polyether polyol, polyester polyol, polyether carbonate polyol and polyether ester polyol.

Description

EXAMPLES

Test Methods

[0123] Hydroxyl number: The OH number was determined according to the method of DIN 53240-1 (method without catalyst, June 2013 version).

[0124] Amine number: Total base number according to DIN 51639-1, in the November 2014 version.

[0125] Acid number: The acid number was determined according to DIN EN ISO 2114 (June 2002).

[0126] Fiber time: The fiber time (gel point tG) is determined by dipping a wooden rod into the reacting polymer melt and withdrawing it again. It characterizes the time from which the polymer melt hardens. The time stated as tG is the time at which threads can for the first time be drawn between the wooden rod and the polymer melt.

[0127] Cream time: The period of time that elapses from the start of mixing the main components up to the visible commencement of foaming of the mixture.

[0128] Viscosity: The dynamic viscosity was measured using the MCR 51 rheometer from Anton Paar in accordance with DIN 53019-1 (September 2008 version) with a CP 50-1 measuring cone (50 mm diameter, 1 angle) at shear rates of 25 s.sup.1, 100 s.sup.1, 200 s.sup.1 and 500 s.sup.1. The polyols according to the invention and not according to the invention display viscosity values that are independent of the shear rate.

[0129] Apparent density: The apparent density was ascertained according to DIN EN ISO 845 (October 2009 version).

[0130] Fire properties: The fire properties were determined according to DIN 4102-1 (May 1998 version).

[0131] Compressive strength:The compressive strength of the rigid PUR/PIR foams was determined according to DIN EN ISO 844 (November 2014 version).

[0132] Open-cell content: The open-cell content of the rigid PUR/PIR foams was ascertained according to DIN EN ISO 4590 (June 2014 version).

Raw Materials Used:

[0133] cPC: cyclic propylene carbonate (Acros)

[0134] cEC: cyclic ethylene carbonate (Acros)

[0135] TMD: propane-1,3-diamine (Abcr GmbH)

[0136] PDA: pentane-1,5-diamine (Sigma-Aldrich)

[0137] A1.2-1: aliphatic polyester polyol obtainable from the reaction of technical grade glutaric acid (mixture of glutaric acid, succinic acid and adipic acid, Lanxess AG) with ethylene glycol, hydroxyl number: 144 mg KOH/g, acid number: 1.7 mg KOH/g, viscosity: 3100 mPas at 25 C.

[0138] A1.2-2: aliphatic polyester polyol obtainable from the reaction of technical grade glutaric acid (mixture of glutaric acid, succinic acid and adipic acid, Lanxess AG) with ethylene glycol, hydroxyl number: 247 mg KOH/g, acid number: 0.9 mg KOH/g, viscosity: 1080 mPas at 25 C.

[0139] A1.2-3: aromatic polyester polyol, hydroxyl number: 230 to 250 mg KOH/g, acid number: 0.6 to 1.0 mg KOH/g (StepanpolPS-2352, Stepan)

[0140] A1.2-4: linear polyester polyol, hydroxyl number: 240 mg KOH/g (Desmophen2382, Covestro Deutschland AG)

[0141] A1.2-5: containing the reaction product of phthalic anhydride and diethylene glycol, acid number: 97 mg KOH/g (Additive 1132, Covestro Deutschland AG)

[0142] A1.2-6: amine-based polyether polyol, hydroxyl number: 395 to 435 mg KOH/g, viscosity: 6450 -9550 mPas at 25 C. (DesmophenT 460, Covestro Deutschland AG)

[0143] A2-1: trischloroisopropyl phosphate (LevagardPP, Lanxess AG)

[0144] A2-2: triethyl phosphate (LevagardTEP-Z, Lanxess AG)

[0145] A3-1: n-pentane (Kraemer&Martin GmbH)

[0146] A3-2: water

[0147] A4-1: N,N-dimethylcyclohexylamine (Desmorapid726 B, Covestro Deutschland AG)

[0148] A4-2: activator for the production of rigid polyurethane foams (DesmorapidDB, Covestro Deutschland AG)

[0149] A4-3: potassium acetate in diethylene glycol (DesmorapidPU 1792, Covestro Deutschland AG)

[0150] A5-1: polyether-modified polysiloxane (TegostabB 8421, Evonik)

[0151] A5-2: modified polyethersiloxane (TegostabB 8443, Evonik)

[0152] B-1: polyisocyanate having an NCO content of 30.5% to 32.5% by weight (Desmodur44V20 L, Covestro Deutschland AG)

Preparation of Diurethane Diols A1.1:

[0153] A four-neck flask with reflux condenser, mechanical stirrer, dropping funnel and thermometer was initially charged with cyclic carbonate at a temperature of 60 C. and under inert gas (N.sub.2). Then, a compound containing at least two amino groups was slowly added dropwise, so that the reaction temperature did not exceed 70 C. The reaction was subsequently stirred at 60 C. for a further 24 h in total. After cooling down to 25 C., the diurethane diol was obtained. The precise formulations and the analytical data with respect to the diurethane diols are compiled in table 1:

TABLE-US-00001 TABLE 1 Formulations and analytical data for the diurethane diols A.1.1-1 to A1.1-4 Diurethane diol A1.1 A1.1-1 A1.1-2 A1.1-3 A1.1-4 cPC [g] 2348.1 449.2 449.2 cEC [g] 387.6 387.6 1549.9 TMD [g] 296.5 PDA [g] 1175.1 408.8 817.4 Analyses Amine [mg KOH/ 8.0 2.7 2.44 2.2 number g] Viscosity [mPas/ >100,000 30,300 21,300 Solid 25 C.] [mPas/ 4850 1930 1580 1370 50 C.] [mPas/ 590 291 260 267 75 C.] Hydroxyl [mg KOH/ 366 425 384 403 number g]

Preparation of Mixtures Containing Diurethane Diol A1.1 and a Compound A1.2:

[0154] The mixtures were prepared by mixing the mixture constituents listed in table 2 at 50 C. by stirring for 30 minutes.

TABLE-US-00002 TABLE 2 Composition of the mixtures containing A1.2-1 and A1.2-2 and also the diurethane diols A1.1-1 to A1.1-4 Example 1 2 3 4 5 6 A1.1-1 [parts by 100 100 weight] A1.1-2 [parts by 100 weight] A1.1-3 [parts by 100 weight] A1.1-4 [parts by 100 200 weight] A1.2-1 [parts by 95.6 187.9 125.6 90.7 109.1 237.6 weight] A1.2-2 [parts by 804.4 712.1 774.4 809.3 790.9 562.4 weight] DUD [% by wt.] 10 10 10 10 10 20 content based on the total weight of the mixture Hydroxyl [mg KOH/g] 250 240 250 250 250 250 number of the mixture

Production of the Rigid PUR/PIR Foams:

[0155] To produce the rigid PUR/PIR foams, the isocyanate-reactive components, flame retardants, catalysts, blowing agents and foam stabilizer are mixed, polyisocyanate is added to the mixture obtained and the mixture is poured into a paper mold (303010 cm.sup.3) and reacted to completion therein. The formulations and results of the physical measurements on the samples obtained are shown in tables 3 to 5.

[0156] Table 3 first shows comparative examples 7 and 8, which were produced on the basis of polyester polyols. Both formulations contain 20 g of flame retardant A2-1 each and achieve the B2 fire classification (table 3: analysis). Examples 9 to 11 according to the invention and comparative example 12 each contain 10% by weight of the diurethane diol A1.1-1, based on the sum total of the masses of components A1.1 and A1.2. The content of flame retardant A2-1 is reduced in this case from 20 g, via 10 g, to 5 g. Examples 9 to 11 according to the invention achieve the B2 fire classification, while comparative example 12, with a flame height of >180 mm, only achieves B3. Furthermore, the rigid PUR/PIR foam of example 9 according to the invention for the same content of flame retardant A2-1 exhibits a lower flame height and hence an improved flame retardancy than the rigid PUR/PIR foams of comparative examples 7 and 8. Halving the content of flame retardant A2-1 for producing the rigid PUR/PIR foam from example 10 according to the invention leads to the same flame retardancy as with the rigid PUR/PIR foam of comparative example 7 (table 3: analysis).

TABLE-US-00003 TABLE 3 Production of rigid PUR/PIR foams using A1.1-1 Example 7 8 12 (comp.) (comp.) 9 10 11 (comp.) A1.2-2 [g] 76.80 A1.2-3 [g] 76.80 Mixture according to [g] 76.49 76.49 76.80 76.80 example 1-1 Proportion of A1. 1-1 [% by weight] .sup.1) 0 0 10 10 10 10 A2-1 [g] 20.00 20.00 20.00 10.00 5.00 0 A3-1 [g] 15.5 15.5 15.5 15.5 15.5 15.5 A3-2 [g] 1.20 1.20 1.20 1.20 1.20 1.20 A4-1 [g] 0.50 0.50 0.50 0.50 0.50 0.50 A4-3 [g] 2.70 2.70 2.70 2.70 2.70 2.70 A5-1 [g] 2.00 2.00 2.00 2.00 2.00 2.00 B-1 [g] 200 200 200 200 200 200 Isocyanate index 289.5 289.5 289.5 289.5 288.7 288.7 Analysis Processing: Cream time [s] 14 9 16 17 19 20 Gel time [s] 53 35 55 52 60 67 Tack-free time [s] 65 44 65 64 70 80 Properties: Apparent density, core [kg/m.sup.3] 31.5 29.7 29.5 29.0 28.4 29.2 Compressive strength, transverse [kPa] 106 84 71 67 84 94 Compressive strength, parallel [kPa] 206 210 194 210 190 209 Open-cell content [%] 9.05 10.68 9.74 9.94 9.58 8.48 Flame height [mm] 120 130 110 120 130-140 >180 Classification B2 B2 B2 B2 B2 B3 .sup.1) Based on the sum total of the masses of components A1.1 and A1.2

TABLE-US-00004 TABLE 4 Production of rigid PUR/PIR foams using A1.1-1 and flame retardant mixtures Example 13 (comp.) 14 15 16 17 A1.2-4 [g] 76.23 Mixture according to [g] 76.23 79.08 80.59 82.15 example 2 A1.2-5 [g] 2.64 2.64 2.74 2.79 2.84 A1.2-6 [g] 5.96 5.96 6.18 6.30 6.42 Proportion of A1. 1-1 [% by 0 9 9 9 9 weight] .sup.1) A2-1 [g] 23.84 23.84 12.37 6.30 0 A2-2 [g] 5.96 5.96 6.18 6.30 6.42 A3-1 [g] 16.16 16.17 16.06 16.01 15.95 A4-2 [g] 1.72 1.72 1.78 1.82 1.85 A4-3 [g] 4.24 4.24 4.40 4.48 4.57 A5-2 [g] 4.01 4.01 4.16 4.24 4.32 B-1 [g] 209.22 209.22 217.04 221.17 225.46 Isocyanate index 325.1 325.1 325.1 325.1 325.1 Processing: Cream time [s] 9 10 10 12 12 Gel time [s] 35 34 36 36 38 Tack-free time [s] 57 44 44 45 45 Properties: Apparent density, core [kg/m.sup.3] 39.26 39.06 38.80 39.03 36.79 Compressive strength, [kPa] 181.67 169.00 175.00 184.00 146.33 transverse Compressive strength, [kPa] 350.33 306.00 324.67 320.33 308.33 parallel Open-cell content [%] 6.33 6.20 5.69 5.23 5.99 Flame height [mm] 120 110-115 115-120 120-125 130 Classification B2 B2 B2 B2 B2 .sup.1) Based on the sum total of the masses of components A1.1 and A1.2

[0157] Table 4 first shows the rigid PUR/PIR foam of comparative example 13, which was produced on the basis of A1.2-4 using a flame retardant mixture composed of A2-1 and A2-2. This formulation achieves the B2 fire classification, as do all rigid PUR/PIR foams of the examples according to the invention (examples 14 to 17). The rigid PUR/PIR foams of the examples according to the invention are distinguished by the fact that proportions of the diurethane diol A1.1-1 are present and the B2 fire classification is achieved. It is surprising that the rigid PUR/PIR foams of examples 15 to 17 according to the invention achieve the B2 fire protection classification even with a reduction of the halogen-containing flame retardant A2-1 or of the total content of the flame retardant. In particular, the rigid PUR/PIR foam of example 17 according to the invention achieves the B2 fire protection classification without any content of halogen-containing flame retardants.

TABLE-US-00005 TABLE 5 Production of rigid PUR/PIR foams using the diurethane diols A1.1-2 to A1.1-4 Example: 18 (comp.) 19 20 21 22 A1.2-3 [g] 76.80 Mixture according to example 3 [g] 76.49 Mixture according to example 4 [g] 76.49 Mixture according to example 5 [g] 76.49 Mixture according to example 6 [g] 76.49 Diurethane diol A1.1-2 A1.1-3 A1.1-4 A1.1-4 Proportion of the respective diurethane diol [% by weight] .sup.1) 0 10 10 10 20 A2-1 [g] 20.00 20.00 20.00 20.00 20.00 A3-1 [g] 15.50 15.50 15.50 15.50 15.50 A3-2 [g] 1.20 1.20 1.20 1.20 1.20 A4-1 [g] 0.50 0.50 0.50 0.50 0.50 A4-3 [g] 2.70 2.70 2.70 2.70 2.70 A5-1 [g] 2.00 2.00 2.00 2.00 2.00 Desmodur 44V20 L [g] 200 200 200 200 200 Index 289.5 289.5 289.5 289.5 289.5 Analysis Processing: Cream time [s] 9 16 17 15 18 Gel time [s] 40 52 52 50 64 Tack-free time [s] 45 61 61 60 75 Properties: Apparent density, core [kg/m.sup.3] 30.3 28.5 29.4 30.9 30.9 Compressive strength, transverse [kPa] 0.090 0.064 0.075 0.069 0.072 Compressive strength, parallel [kPa] 0.228 0.171 0.192 0.232 0.217 Open-cell content [%] 10.03 8.60 8.71 7.54 7.72 Flame height [mm] 130 110-120 110-120 120 130 Classification B2 B2 B2 B2 B2 .sup.1) Based on the sum total of the masses of components A1.1 and A1.2

[0158] Table 5 first shows the rigid PUR/PIR foam of comparative example 18, which was produced on the basis of A1.2-3 using the flame retardant A2-1. This rigid PUR/PIR foam achieves the B2 fire classification, as do all rigid PUR/PIR foams of the examples according to the invention (examples 19 to 22), which, however, are distinguished by the fact that the rigid PUR/PIR foams according to the invention contain proportions of diurethane diols (A1.1-2 to A1.1-4) of 10% or 20% by weight based on the sum total of the masses of components A1.1 and A1.2. The rigid PUR/PIR foams of examples 19 to 21 according to the invention exhibit a better flame retardancy than the rigid PUR/PIR foam of comparative example 18. The use of a proportion of 20% by weight of a diurethane diol, based on the sum total of the masses of components A1.1 and A1.2, in the production of the rigid PUR/PIR foam in example 22 according to the invention results in the same flame retardancy as for the rigid PUR/PIR foam of comparative example 18 with almost unchanged apparent density and compressive strength of the rigid PUR/PIR foam. Advantageously, a high proportion of cyclic carbonates from the production of polyether carbonate polyols was used in example 22 according to the invention.