POLYURETHANES

Abstract

A process for making a flame retardant polyurethane foam, the process comprising reacting a PO based polyol with foam-forming reactants to provide said polyurethane foam, wherein said polyol is prepared by ring-opening polymerization of alkylene oxide in the presence of a composite metal cyanide complex catalyst, and wherein said polyol is either free from EO moieties or comprises EO moieties in an amount of at most 1% w/w.

Claims

1. A process for making a flame retardant polyurethane foam, the process comprising reacting a PO based polyol with foam-forming reactants to provide said polyurethane foam, wherein said polyol is prepared by ring-opening polymerization of alkylene oxide in the presence of a composite metal cyanide complex catalyst, and wherein said polyol is either free from EO moieties or comprises EO moieties in an amount of at most 1% w/w.

2. The process of claim 1 wherein said polyol contains EO moieties, if any, in an amount of at most 0.8% w/w.

3. The process of claim 1, wherein the polyol comprises only PO moieties.

4. The process of claim 1, wherein said polyol has a number average molecular weight in the range of from 2750 to 4000 Dalton and a nominal functionality (F.sub.n) in the range of from 2 to 3.5.

5. The process of claim 1, wherein said polyol is obtained by reacting an initiator having a plurality of active hydrogen atoms with PO and optionally EO, the initiator being introduced continuously to a reactor together with the alkylene oxide and the catalyst, to carry out the polymerization of the alkylene oxide.

6. The process of claim 1, wherein said polyol has a polydispersity index (Mw/Mn) in the range of from 1.18 to 1.5.

7. The process of claim 1, wherein the foam includes a flame retardant effective amount of flame retardant such that the foam passes flame resistance standard BS 5852, Part 2, Crib 5.

8. The process of claim 1, wherein said foam-forming reactants include melamine in an amount of between about 10 and about 15 php, a halogenated phosphate supplemental flame retardant in an amount of between 4 and about 10 php, and water in an amount of between about 3 and about 6 php.

9. A polyurethane foam obtainable by the process of claim 1.

10. A shaped article comprising a polyurethane foam as claimed in claim 9.

11. (canceled)

Description

EXAMPLE 1

[0054] The flammability of foams produced from a first set of polyols was tested.

[0055] Polyol 1 (Comparative) had a number average molecular weight of about 3000 Dalton, a nominal functionality of 3.0 and was entirely PO based. It was produced by ring-opening polymerization of propylene oxide in the presence of an alkali metal catalyst (KOH).

[0056] Polyol 2 had a number average molecular weight of about 3000 Dalton, a nominal functionality of about 2.8 and was entirely PO based (0% w/w EO). It was produced by continuous ring-opening polymerization of propylene oxide in the presence of a composite metal cyanide complex catalyst.

[0057] Polyol 3 had a number average molecular weight of about 3000 Dalton, a nominal functionality of about 2.8 and included a mixture of PO and EO moieties, with EO moieties making up about 1% w/w. It was produced by continuous ring-opening polymerization of propylene oxide in the presence of a composite metal cyanide complex catalyst.

[0058] Polyol 4 (Comparative) had a number average molecular weight of about 3000 Dalton, a nominal functionality of about 2.8 and included a mixture of PO and EO moieties, with EO moieties making up about 3% w/w. It was produced by continuous ring-opening polymerization of propylene oxide in the presence of a composite metal cyanide complex catalyst.

[0059] Each of polyols 1 to 4 was in turn processed into a polyurethane foam under identical conditions, using the reaction mixture shown in Table 1:

TABLE-US-00001 TABLE 1 Component Amount Polyol (as above) pbw 100 Water (blowing agent) php 3.5 33LV (tertiary amine catalyst) php 0.18 L620 (surfactant) php 0.8 Mealmine (flame retardant) php 12 TMCP (flame retardant) php 7 DeOA (dienthanolamine crosslinker) php 0.2 T-9 (stannous octoate catalyst) php 0.26 TDI index (using TDI 80) 110

[0060] Each foam was subjected to the BS5852, Part 2, Crib 5 test and the weight loss results are shown in Table 2 (average of five tests):

TABLE-US-00002 TABLE 2 Originating Initial foam Final foam Wt polyol weight (g) weight (g) loss (g) Polyol 1 794.7 749.5 45.2 Polyol 2 789.4 766.3 23.1 Polyol 3 698.6 662.0 36.6 Polyol 4 734.6 651.0 83.6

[0061] It is noted that Polyols 2 and 3 prepared in accordance with the invention showed enhanced fire resistance compared to Polyols 1 and 4.

EXAMPLE 2

[0062] Polyol 3 from Example 1 was compared with a further polyol, Polyol 5.

[0063] Polyol 5 is a BAYER polyol sold under the trade mark ARCOL 1105S. It had a number average molecular weight of about 3000 and included a mixture of PO and EO moieties, with EO moieties making up about 1% w/w. Polyol 5 is believed to have been produced by batch-based ring-opening polymerization of propylene oxide in the presence of a composite metal cyanide complex catalyst.

[0064] The polydispersity index (Mw/Mn) of Polyol 3 and Polyol 5, was determined to be about 1.25 and 1.15 respectively.

[0065] Each of Polyol 3 and 5 was in turn processed into a polyurethane foam under identical conditions, using the reaction mixture shown in Table 3:

TABLE-US-00003 TABLE 3 Component Amount Polyol (as above) pbw 100 Water (blowing agent) php 3.5 33LV (tertiary amine catalyst) php 0.18 L620 (organosilicone surfactant) php 0.8 Mealmine (flame retardant) php 20 TMCP (flame retardant) php 10 DeOA (dienthanolamine crosslinker) php 0.5 T-9 (stannous octoate catalyst) php 0.22 Polyol (as above) pbw 100 TDI index (using TDI 80) 114

[0066] Each foam was subjected to the BS5852, Part 2, Crib 5 test and the results are shown in Table 4 (average of five tests):

TABLE-US-00004 TABLE 4 Originating Initial foam Final foam Wt loss polyol weight (g) weight (g) (g) Polyol 3 759 727 32 Polyol 5 757 719 38

[0067] It is noted that Polyol 3, prepared with a continuous process and having a higher polydispersity index, showed enhanced fire resistance compared to Polyol 5.