Polyamide foams which inhibit the spread of fires for filling cavities in mining

Abstract

Polyamide foams which do not propagate fire are obtained by mixing (i) a liquid isocyanate component which comprises at least one polyisocyanate and in which the molar ratio of aromatic isocyanate groups to the sum of aromatic and aliphatic isocyanate groups is at least 60 mol %, with (ii) at least one liquid isocyanatereactive component which comprises a reactive diluent, and the reactive diluent 10 comprises (a) a chain-extending and/or crosslinking reactive diluent selected from among aliphatic branched C.sub.24-66-polycarboxylic acids, alicyclic C.sub.24-66-polycarboxylic acids and partial esters of polycarboxylic acids having at least two unesterified carboxyl groups and/or (b) a chain-terminating reactive diluent selected from among aliphatic branched C.sub.24-66-monocarboxylic acids, alicyclic C.sub.24-66-monocarboxylic acids and partial esters of polycarboxylic acids having one unesterified carboxyl group, wherein the liquid isocyanate-reactive component comprises an aromatic C.sub.8-18-polycarboxylic acid and/or an anhydride thereof.

Claims

1. A process for producing polyamide foams which do not propagate fire by mixing (i) a liquid isocyanate component which comprises at least one polyisocyanate and in which the molar ratio of aromatic isocyanate groups to the sum of aromatic and aliphatic isocyanate groups is at least 60 mol % with (ii) at least one liquid isocyanate-reactive component which comprises a reactive diluent, where the reactive diluent comprises (a) a chain-extending and/or crosslinking reactive diluent selected from the group consisting of aliphatic branched C.sub.24-66-polycarboxylic acids, alicyclic C.sub.24-66-polycarboxylic acids, partial esters of polycarboxylic acids having at least two unesterified carboxyl groups, and mixtures thereof and/or (b) a chain-terminating reactive diluent selected from the group consisting of aliphatic branched C.sub.24-66-monocarboxylic acids, alicyclic C.sub.24-66-monocarboxylic acids, partial esters of polycarboxylic acids having one unesterified carboxyl group, and mixtures thereof, and (iii) optionally a solid isocyanate-reactive component, where the liquid isocyanate-reactive component and/or the solid isocyanate-reactive component comprises an aromatic C.sub.8-18-polycarboxylic acid and/or an anhydride thereof; wherein the molar ratio of aromatic carboxyl groups to the sum of aromatic and aliphatic carboxyl groups in (ii) and (iii) is at least 10 mol %.

2. The process according to claim 1, wherein the liquid isocyanate component comprises diphenylmethane diisocyanate, a mixture of monomeric diphenylmethane diisocyanate and homologs of diphenylmethane diisocyanate having more than two rings or prepolymers of diphenylmethane diisocyanate or mixtures thereof.

3. The process according to claim 1, wherein the aliphatic, branched C.sub.24-66-polycarboxylic acid and/or alicyclic C.sub.24-66-polycarboxylic acid is selected from the group consisting of dimeric fatty acids, trimeric fatty acids and mixtures thereof, which are optionally hydrogenated.

4. The process according to claim 1, wherein the liquid isocyanate component, the liquid isocyanate-reactive component and/or the solid isocyanate-reactive component comprises a polyaddition catalyst.

5. The process according to claim 4, wherein the polyaddition catalyst is selected from the group consisting of tin-organic compounds, tertiary amines, alkaline earth metal salts, and mixtures thereof.

6. The process according to claim 1, wherein the liquid isocyanate component and/or the liquid isocyanate-reactive component comprises a foam stabilizer.

7. The process according to claim 1, wherein the liquid isocyanate component, the liquid isocyanate-reactive component and/or the solid isocyanate-reactive component comprises a flame retardant.

8. A process for filling cavities in mining, tunnel construction, civil engineering or in oil and gas recovery using a polyamide foam which does not propagate fire, wherein the process comprises mixing the liquid isocyanate component, the liquid isocyanate-reactive component and optionally the solid isocyanate-reactive component as defined in claim 1 and introducing the mixture into the cavity.

9. The process according to claim 8 further comprising delimiting the cavity by means of formwork and introducing the mixture into the delimited cavity.

10. A polyamide foam obtained by the process according to claim 1.

Description

(1) The invention is illustrated by the following examples and figures.

(2) FIG. 1 shows the temperature-time curve of the punking test in accordance with BS 5946:1980 for the foam as per example 9.

(3) FIG. 2 schematically shows the positioning of the Bunsen burner and the temperature sensors in the punking test.

(4) The following commercial chemicals were used for the following examples: Lupranat M10R (BASF) Polymeric methlyenedi(phenyl isocyanate) (NCO content 31.7%, nominal NCO functionality 2.2) Lupranat M20R (BASF) Polymeric methylenedi(phenyl isocyanate) (NCO content 31.4%, nominal NCO functionality 2.7) Lupranat M200R (BASF) Polymeric methylenedi(phenyl isocyanate) (NCO content 31%, nominal NCO functionality 3) Jeffcat ZR 50 (Huntsman) N,N-Bis(3-dimethylaminopropyl)-N-isopropanolamine Jeffcat ZR 70 (Huntsman) 2-(2-Dimethylaminoethoxy)ethanol Lupragen N106 (BASF) 4,4-(Oxydi-2,1-ethanediyl)bismorpholine Lupragen N201 (BASF) Diazabicyclooctane Lupragen N600 (BASF) 1,3,5-Tris(dimethylaminopropyl)-sym-hexahydrotriazine Lupragen TCPP (BASF) Trichloropropyl phosphate Empol 1062 (BASF) Fatty acid dimer based on tall oil (distilled, partially hydrogenated) Empol 1043 (BASF) Fatty acid trimer based on tall oil Pripol 1017 (Croda) Fatty acid dimer (acid number 190-197 mg KOH/g) Pripol 1040 (Croda) Fatty acid trimer (acid number 184-194 mg KOH/g) Tegostab B 8407 (Evonik) Polyoxyalkylene-polysiloxane

(5) The liquid components 1 and 2 described below and optionally the solid component 2.1 are mixed at ambient temperature using a mechanical stirrer or wooden spatula. The mixtures foam spontaneously and after curing form a solid polyamide foam.

EXAMPLE 1

(6) Component 1: 6 g of Lupranat M20R.

(7) Component 2: 5 g of Empol 1062 and 0.5 g of Jeffcat ZR 70.

(8) Component 2.1: 1.2 g of isophthalic acid.

EXAMPLE 2

(9) Component 1: 6 g of Lupranat M20R.

(10) Component 2: 5 g of Empol 1062 and 0.5 g of Jeffcat ZR 70 and 1.2 g of isophthalic acid (predissolved in 4 g of triethyl phosphate).

EXAMPLE 3

(11) Component 1: 6 g of Lupranat M20R.

(12) Component 2: 5 g of Empol 1062 and 0.5 g of Jeffcat ZR 70 and 0.2 g of Tegostab B 8407 and 1.2 g of isophthalic acid (dispersed therein).

EXAMPLE 4

(13) Component 1: 6 g of Lupranat M20R.

(14) Component 2: 4.5 g of Empol 1043 and 0.5 g of Jeffcat ZR 70.

(15) Component 2.1: 1.2 g of terephthalic acid.

EXAMPLE 5

(16) Component 1: 6 g of Lupranat M10R.

(17) Component 2: 4.5 g of Empol 1043 and 0.5 g of Jeffcat ZR 70 and 0.2 g of Tegostab B 8407.

(18) Component 2.1: 1.2 g of isophthalic acid

EXAMPLE 6

(19) A foam piece having a density of 70 kg/m.sup.3 was produced as per example 5. A prism resulting from this foam piece was subjected to mechanical compressive testing.

(20) An average compressive strength of 0.2 N/mm.sup.2 at a compression of 10% was obtained.

EXAMPLE 7

(21) A foam piece having a density of 75 kg/m.sup.3 was produced as per example 5. A plate having the dimensions 20×20×4 cm resulting from this foam piece was examined to determine its thermal conductivity. This had a thermal conductivity of 51 mW/(m*K).

EXAMPLE 8

(22) A foam piece produced as per example 5 was examined by thermogravimetry. The decomposition of the foam commenced at a temperature of 420° C.

EXAMPLE 9

(23) Based on example 5, a batch having four times the amount of catalyst (relative to the total amount of the other components) and an increased batch size was used for producing 200 g of curable mixture in order to examine the heat of reaction. The components which had been preheated to 30° C. were mixed and the reaction temperature was measured during foaming. The maximum reaction temperature was 50° C.

(24) A 12×12×12 cm cube having a density of 45 kg/m.sup.3 obtained from the resulting foam block was subjected to a punking test in accordance with BS 5946:1980 to examine the fire propagation behavior. Here, 2 temperature sensors were introduced into the foam piece and a nonluminous Bunsen burner flame was subsequently applied to the foam for 50 minutes (see FIG. 2). After the end of the flame application time, the temperature at the temperature sensor T2 was measured until it had dropped to <40° C.; the temperature curve is shown in FIG. 1. In the experiment, the recorded temperatures decreased immediately after the flame was taken away. Burning thus neither continued nor spread. The cut-open foam cube was undamaged in the upper third after the test. In the damaged region of the test specimen, the foam remained in the form of a carbonized substance having a residual strength. Since burning did not continue and no complete carbonization of the material occurred during the test, the foam body passed the test.

EXAMPLE 10 (COMPARATIVE EXAMPLE)

(25) Component 1: 6 g of Lupranat M10R.

(26) Component 2: 4 g of Pripol 1017, 2 g of Pripol 1040 and 0.6 g of water and 1 g of 4,4-(oxydi-2,1-ethanediyl)bismorpholine (Lupragen N106) and 0.5 g of Tegostab B 8407.

(27) 14 seconds after mixing of the first component with the second component, the mixture begins to foam. Foaming ends after 2 minutes with a 14-fold increase in volume. A tack-free, solid foam which in contrast to the foams from examples 1-5 has a very fine foam structure is formed.

EXAMPLE 11

(28) Component 1: 6 g of Lupranat M10R.

(29) Component 2: 4 g of Pripol 1017, 2 g of Pripol 1040 and 0.6 g of water and 1 g of 4,4-(oxydi-2,1-ethanediyl)bismorpholine (Lupragen N106) and 0.5 g of Tegostab B 8407.

(30) Component 2.1: 1.2 g of isophthalic acid.

(31) In contrast to the foams of examples 1-5, this foam has a very fine foam structure.

EXAMPLE 12

(32) Component 1: 6 g of Lupranat M20R.

(33) Component 2: 2 g of Pripol 1017, 4 g of Pripol 1040, 0.6 g of water, 0.15 g of 4,4-(oxydi-2,1-ethanediyl)bismorpholine (Lupragen N106), 1.0 g of Jeffcat ZR50, 0.5 g of Tegostab B 8407 and 3 g of isophthalic acid (homogeneously dispersed therein).

(34) The resulting foam has a finer foam structure than examples 1-5. A foam piece produced according to this formulation was subjected to a punking test in accordance with BS 5946:1980 in a manner analogous to example 9. The foam body passed the test. Compared to the foams of examples 10 and 11, this foam displays a better burning behavior, i.e. it is less readily flammable, self-extinguishing, carbonizes and melts to a lesser extent.

EXAMPLE 13

(35) Component 1: 6 g of Lupranat M20R.

(36) Component 2: 2 g of Pripol 1017, 4 g of Pripol 1040, 0.6 g of water, 0.15 g of 4,4-(oxydi-2,1-ethanediyl)bismorpholine (Lupragen N106), 1.0 g of Jeffcat ZR50, 0.5 g of Tegostab B 8407, 2 g of isophthalic acid and 1 g of trimellitic acid (homogeneously dispersed therein).

(37) The resulting foam has a finer foam structure than examples 1-5, but a better burning behavior than examples 10 and 11 (less readily flammable, self-extinguishing, carbonizes and melts to a lesser extent).

EXAMPLE 14

(38) Polyamide foams were produced as follows from the components and amounts (in g) summarized in the following table: all components with the exception of Lupranat M200R were mixed; the Lupranat M200R was then mixed in. The mixtures foamed and after curing formed a solid polyamide foam. A 12×12×12 cm.sup.3 cube was cut from the foam pieces after 24 hours. The burning behavior of the cubes was examined in the punking test described in example 9. The temperatures T1 (bottom) and T2 (middle) attained after 10 and 20 minutes are likewise reported in the table.

(39) TABLE-US-00001 A B C-1 C-2 C-3 Lupranat M200R 72.0 72.0 63.5 55.8 51.3 Isophthalic acid 40.0 31.3 24.4 17.6 Adipic acid 35.0 Pripol 1040 102.0  102.0  120.0 133.4 146.3 Water  0.6  0.6 0.6 0.6 0.6 Lupragen N201  8.0  8.0 8.0 8.0 8.0 Lupragen N600  4.0  4.0 4.0 4.0 4.0 Lupragen TCPP 25.0 25.0 25.0 25.0 25.0 Triethyl phosphate 15.0 15.0 15.0 15.0 15.0 T1(after 10/20* min) 364*   359*   140 158 239 T2(after 10/20* min) 75*  172*   46 120 90

(40) Comparison of experiments A and B shows that after 20 minutes and at a comparable temperature T1, the temperature T2 is increased only moderately in experiment A, while T2 is increased significantly more greatly in experiment B. This demonstrates that foam A has a lower fire-propagating behavior.

(41) The series C-1, C-2 and C-3 shows that with decreasing ratio of isophthalic acid/Pripol 1040, the combustibility of the foam increases, which can be seen from the greater increase in the temperature T1 after 10 minutes.