PROCESS FOR PREPARING POLYISOCYANURATE RIGID FOAMS

Abstract

Provided herein is a process for preparing a rigid polyisocyanurate foam including reacting a composition (A) including a polyesterol, a blowing agent including formic acid, a catalyst system including at least one trimerization catalyst and at least one polyisocyanate as component (B), wherein composition (A) further includes at least one polyether alcohol prepared by addition of alkylene oxides to toluenediamine. Further provided herein is a rigid polyisocyanurate foam obtained through the process described herein and the use of said rigid polyisocyanurate foam as insulating material.

Claims

1. A process for preparing a rigid polyisocyanurate foam comprising: reacting: (A) a composition (A) comprising: a polyesterol, a blowing agent comprising formic acid, and a catalyst system comprising at least one trimerization catalyst, and (B) at least one polyisocyanate as component (B), wherein composition (A) further comprises at least one polyether alcohol prepared by addition of alkylene oxides to toluenediamine.

2. The process according to claim 1, wherein the rigid polyisocyanurate foam has a proportion of closed cells in accordance with DIN ISO 4590 of greater than 85%.

3. The process according to claim 1, wherein the rigid polyisocyanurate foam has a compressive strength in accordance with DIN 53 421/DIN EN ISO 604 of greater than or equal to 80 kPa.

4. The process according to claim 1, wherein the polyether alcohol prepared by addition of alkylene oxides to toluenediamine has a hydroxyl number in the range from 100 to 600.

5. The process according to claim 1, wherein the polyesterol is selected from the group consisting of polyesterols prepared from phthalic acid, terephthalic acid, and a derivative thereof.

6. The process according to claim 1, wherein the trimerization catalyst is selected from the group consisting of potassium formate, potassium acetate, potassium octanoate, ammonium formate, ammonium acetate, ammonium octanoate and mixtures thereof.

7. The process according to claim 1, wherein the catalyst system comprises a further catalyst component that is an amine compound that has a maximum of 6 nitrogen atoms.

8. The process according to claim 1, wherein the blowing agent comprises formic acid and physical blowing agents.

9. The process according to claim 1, wherein the composition (A) comprises less than 2.0% by weight of water.

10. The process according to claim 1, wherein composition (A) comprises a further component selected from stabilizers, flame retardants and other additives.

11. The process according to claim 1, wherein the polyisocyanate is an aromatic polyisocyanate.

12. The process according to claim 1, wherein to produce the rigid polyisocyanurate foams, the composition (A) and component (B) are reacted in such amounts that the isocyanate index is from 150 to 500.

13. A rigid polyisocyanurate foam obtained through a process according to claim 1.

14. A method of using a rigid polyisocyanurate foam obtained through a process according to claim 1 or comprising using the rigid polyisocyanurate foam as insulating material.

Description

EXAMPLES

[0145] The invention is illustrated by the following examples. [0146] 1. General procedure [0147] Polyurethane rigid foams 5 to 7, 9 and 11 according to the invention were prepared as well as comparative foams C1 to C4, C8, C10 and C12. [0148] The components reactive towards isocyanates, the foaming agents, catalysts and further components were mixed to give the polyol composition (A-component) which was then foamed with the isocyanate in a ratio of 1502 (mixing ratio for comparative example C12 100:110). [0149] Foaming was carried out in a cup using a mixer with 1400 rpm and a mixing time of 5 seconds. The free foaming density and the reaction time were determined using the cup test. The cup test was repeated after storage of the polyol composition (A-component) for 1 day, 14 days and 28 days at a temperature of 222 C. [0150] The flame height was determined according to EN ISO 11925-2. [0151] 2. Results [0152] The results are summarized in table 1a and 1b. The results show that the compositions according to the invention have an improved storage stability. The increase of the gel time after storage of the A component for 14 and 28 days is only small. In contrast to this, the comparative examples show an increase of the gel time after storage of the A component for 14 days which makes the use of these systems for foam preparation difficult or impossible. [0153] The burning properties of the foams according to the present invention are good and all polyisocyanurate foams according to the invention fulfill class E of the European standards (flame height<15 cm).

TABLE-US-00001 TABLE 1a Example C1 C2 C3 C4 5 6 7 Polyester 1 56.5 Polyester 2 56.5 41.5 41.5 41.5 46.5 51.5 Polyether 1 15 10 5 Polyether 2 15 Polyether 3 15 Polyether 4 10 10 10 10 10 10 10 stabilizer 2 2 2 2 2 2 2 TCPP 25 25 25 25 25 25 25 Formic acid 99% 5 5 5 5 5 5 5 Dabco TMR2 1 1 1 1 1 1 1 Toyocat TRX Potassiumformiate Amine catalyst 1 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Amine catalyst 2 Amine catalyst 3 NCO Index 238 221 204 198 205 210 215 Small burner test according to EN ISO 11925-2 Average flame 9 8 10 10 10 10 9 height (cm) classification E E E E E E E Reactivity after 24 hours Start time (s) 12 9 10 12 7 6 7 gel time (s) 90 86 95 96 86 95 95 cup density (kg/m.sup.3) 43 43 43 43 43 42 42 Reactivity after 14 days Start time (s) 14 12 12 12 7 7 8 gel time (s) 115 108 115 112 87 95 98 gel time (s) +25 +22 +20 +16 +1 0 +3 cup density (kg/m.sup.3) 46 47 45 45 45 45 44 Reactivity after 28 days Start time (s) 14 12 12 12 7 8 9 gel time (s) 120 115 122 123 87 103 108 gel time (s) +30 +29 +27 +27 +1 +8 +13 cup density (kg/m.sup.3) 49 50 49 48 48 47 48

TABLE-US-00002 TABLE 1b Example C8 9 C10 11 C12 Polyester 1 56.9 41.9 56.8 41.8 40 Polyester 2 Polyether 1 15 15 Polyether 2 Polyether 3 42 Polyether 4 10 10 10 10 stabilizer 2 2 2 2 2 TCPP 25 25 25 25 10 Formic acid 99% 5 5 5 5 5 Dabco TMR2 Toyocat TRX 0.7 0.7 Potassium 0.6 0.6 formiate Amine catalyst 1 0.5 0.5 0.1 Amine catalyst 2 0.5 0.5 Amine catalyst 3 0.9 NCO Index 234 212 235 213 117 Small burner test according to EN ISO 11925-2 Average flame 5 7 9 10 >>15 height (cm) classification E E E E F Reactivity after 24 hours Start time (s) 12 8 12 7 10 gel time (s) 88 85 87 82 145 cup density 41 41 40 42 42 (kg/m.sup.3) Reactivity after 14 days Start time (s) 13 8 14 7 11 gel time (s) 112 92 105 86 145 gel time (s) +24 +7 +18 +4 0 cup density 44 43 43 45 42 (kg/m.sup.3) Reactivity after 28 days Start time (s) 13 9 16 7 12 gel time (s) 123 94 115 88 148 gel time (s) +35 +9 +28 +6 +3 cup density 49 46 44 46 47 (kg/m.sup.3) [0154] 3. Raw Materials Used [0155] Polyester 1: polyesterol prepared from phthalic anhydride, diethylene glycol, and oleic acid, functionality=2, OHN=210 mg KOH/g [0156] Polyester 2: polyesterol prepared from terephthalic acid, diethylene glycol, and oleic acid, functionality=2.5, OHN=245 mg KOH/g [0157] Polyether 1: polyether prepared from TDA, ethylene oxide and propylene oxide; functionality=3.8, OHN=390 mg KOH/g [0158] Polyether 2: polyetherol prepared from ethylene diamine, and propylene oxide; functionality=3.9, OHN=470 mg KOH/g [0159] Polyether 3: polyetherol prepared from saccharose, pentaerythrite, diethylene glycol, and propylene oxide; functionality=3.9, OHN=403 mg KOH/g [0160] Polyether 4: polyetherol prepared from propylene glycol and propylene oxide, functionality=2, OHN=104 mg KOH/g [0161] Stabilizer Niax silicon L 6900 from company Momentive [0162] Flame retardant TCPP (trischloroisopropyl phosphate) [0163] Dabco TMR2: PIR catalyst from company Air Products [0164] Toyocat TRX: PIR catalyst from company Tosoh [0165] Potassium formiate: 40% in monoethylene glycol [0166] Amine catalyst 1: bis-2-dimethylether 70% in dipropylene glycol [0167] Amine catalyst 2: 2-2-dimethylaminoethylmethyl-amino-ethanol [0168] Amine catalyst 3: N,N-dimethylcyclohexylamine [0169] Isocyanate: Lupranat M2OS from BASF SE, PMDI with an NCO-content of 31% and an average functionality of 2.7