FLAME-RETARDED RIGID POLYURETHANE FOAMS

Abstract

A process for producing rigid PUR/PIR foams comprising A1 an isocyanate-reactive component, A2 a flame retardant, A3 a blowing agent, A4 a catalyst, A5 optionally auxiliaries and additives, and B an organic polyisocyanate component. Component A1 comprises a triurethane triol 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 comprising A1 an isocyanate-reactive component, A2 a flame retardant, A3 a blowing agent, A4 a catalyst, A5 optionally auxiliaries and additives, and B an organic polyisocyanate component, wherein component A1 comprises a triurethane triol 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 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 triurethane triol 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 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.4 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.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, R.sup.6 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.7 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, and wherein R.sup.1 to R.sup.7 may be identical or different from one another.

7. The process as claimed in claim 1, wherein the triurethane triol A1.1 is obtained from the reaction between cyclic ethylene carbonate and/or cyclic propylene carbonate with a compound containing at least three amino groups, wherein at least two of the amino groups are primary amino groups.

8. The process as claimed in claim 1, wherein the proportion of triurethane triol 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 triurethane triol 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

[0132] Test methods: [0133] Hydroxyl number: The OH number was determined according to the method of DIN 53240-1 (method without catalyst, June 2013 version). [0134] Amine number: Total base number according to DIN 51639-1, in the November 2014 version. [0135] Acid number: The acid number was determined according to DIN EN ISO 2114 (June 2002). [0136] Fiber time: The fiber time (gel point t.sub.G) 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 to is the time at which threads can for the first time be drawn between the wooden rod and the polymer melt. [0137] 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. [0138] 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. [0139] Apparent density: The apparent density was ascertained according to DIN EN ISO 845 (October 2009 version). [0140] Fire properties: The fire properties were determined according to DIN 4102-1 (May 1998 version). [0141] Compressive strength: The compressive strength of the rigid PUR/PIR foams was determined according to DIN EN ISO 844 (November 2014 version). [0142] Open-cell content: The open-cell content of the rigid PUR/PIR foams was ascertained according to DIN EN ISO 4590 (June 2014 version).

[0143] Raw Materials Used: [0144] cPC: cyclic propylene carbonate (Acros) [0145] DBU: 1,8-diazabicyclo(5.4.0)undec-7-ene [0146] DETA: diethylenetriamine [0147] A1.2-1: aliphatic polyester polyol formed from technical grade glutaric acid (mixture of glutaric acid, succinic acid and adipic acid, Lanxess AG) and ethylene glycol, hydroxyl number: 237 mg KOH/g, acid number: 1.9 mg KOH/g, viscosity: 1160 mPas at 25 C. [0148] A1.2-2: linear polyester polyol, hydroxyl number: 240 mg KOH/g (Desmophen2382, Covestro Deutschland GmbH) [0149] A1.2-3: containing the reaction product of phthalic anhydride and diethylene glycol, acid number: 97 mg KOH/g (Additive 1132, Covestro Deutschland AG) [0150] A1.2-4: amine-based polyether polyol, hydroxyl number: 395 to 435 mg KOH/g, viscosity: 6450-9550 mPas at 25 C. (DesmophenT 460, Covestro Deutschland GmbH) [0151] A2-1: trischloroisopropyl phosphate (LevagardPP, Lanxess AG) [0152] A2-2: triethyl phosphate (LevagardTEP-Z, Lanxess AG) A3-1: n-pentane (Kraemer&Martin GmbH) [0153] A4-1: activator for the production of rigid polyurethane foams (DesmorapidDB, Covestro Deutschland AG) [0154] A4-2: potassium acetate in diethylene glycol (DesmorapidPU 1792, Covestro Deutschland AG) [0155] A5-1: modified polyethersiloxane (TegostabB 8443, Evonik) [0156] B-1: polyisocyanate having an NCO content of 30.5% to 32.5% by weight (Desmodur44V20 L, Covestro Deutschland AG)

[0157] Preparation of Triurethane Triol A1.1-1:

[0158] A 500 ml flange reactor with heatable jacket and electric stirrer is initially charged with 348.7 g (3.42 mol) of cPC and 2.22 g (14.6 mmol) of DBU under inert gas (N.sub.2). Thereafter, 50.3 g (0.49 mol) of DETA is added dropwise over the course of one hour while stirring and at 100 C. Subsequently, the reaction was stirred further for a total of 6 h at 100 C.

[0159] Excess cPC was removed by short-path evaporation at a pressure of 0.01 mbar, with the jacket temperature being 140 C. and a metering rate of 200 g/hour being selected.

[0160] Analysis: [0161] Viscosity: 95 500 mPas (50 C.), 3900 mPas (75 C.) [0162] Hydroxyl number: 366 mg KOH/g [0163] Amine number: 43.3 mg KOH/g

[0164] Preparation of a Mixture Containing a Triurethane Triol A1.1 and a Compound A1.2:

[0165] 10 g of the triurethane triol A1.1-2 are preheated to 100 C. in a drying cabinet and added to 90 g of A1.2-1 preheated to 60 C. The mixture is stirred by means of a Pendraulik stirrer until homogeneous and has a hydroxyl number of 250 mg KOH/g.

[0166] Production of the Rigid PUR/PIR Foams:

[0167] 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 table 1.

TABLE-US-00001 TABLE 1 Production of rigid PUR/PIR foams using A1.1-1 Example 1 (comp.) 2 3 4 A1.2-2 [g] 74.9 Mixture containing [g] 76.4 79.2 80.7 TUT A1.1-1 and polyester polyol A1.2-1 A1.2-3 [g] 2.59 2.64 2.74 2.79 A1.2-4 [g] 5.86 5.97 6.19 6.31 A2-1 [g] 23.4 23.9 12.4 6.3 A2-2 [g] 5.86 5.97 6.19 6.31 A3-1 [g] 16.13 15.92 15.82 15.77 A4-1 [g] 1.69 2.87 2.98 3.03 A4-2 [g] 4.17 3.22 3.34 3.4 A5-1 [g] 3.94 4.02 4.17 4.25 B-1 [g] 211.4 209.1 217 221.1 Isocyanate index 325.1 325.1 325.1 325.1 Analysis Processing: Cream time [s] 15 17 17 18 Gel time [s] 43 47 46 46 Tack-free time [s] 63 65 61 66 Properties: Apparent density, core [kg/m.sup.3] 42.3 41.6 41.4 41.2 Compressive strength, [kPa] 225 202 205 209 transverse Compressive strength, [kPa] 375 318 336 342 parallel Open-cell content [%] 5.2 5.7 5.7 5.1 Flame height [mm] 140-145 125-130 135-140 130-140 Classification B2 B2 B2 B2

[0168] Table 1 shows in examples 2 to 4 that the use of the mixture according to the invention leads to rigid PUR/PIR foams having a B2 fire classification. Compared with comparative example 1, the rigid PUR/PIR foams of the process according to the invention (examples 2 to 4 according to the invention) possess improved flame retardancy (see table 1: analysis). Examples 3 and 4 according to the invention show that the proportion of flame retardant in the rigid PUR/PIR foams, in particular of the halogen-containing flame retardant TCPP, can be reduced. Despite a reduced proportion of flame retardant, the flame retardancy of the rigid PUR/PIR foams is at least equivalent to the flame retardancy of the rigid PUR/PIR foams of comparative example 1.

[0169] In addition, table 1 (analysis) proves that all relevant processing-related parameters, such as for example cream time, gel time and tack-free time, remain practically unchanged compared to comparative example 1 if relatively small adjustments of the catalysts and stabilizers are made. Under these prerequisites, all mechanical properties of the rigid PUR/PIR foams of the examples according to the invention also maintain the level given by comparative example 1.