USE OF ALIPHATIC ISOCYANATE AS TOXIC FUME SUPRESSANT IN POLYURETHANE FOAMS

Abstract

The present invention relates to the field of polyurethane foams and the way to reduce the smoke and the toxic compounds created when the foam burns.

Claims

1. A method comprising: suppressing a toxic fume in polyurethane foam with an aliphatic isocyanate, wherein the aliphatic isocyanate component is included in the polyurethane foam by reacting with at least one polyol compound.

2. The method of claim 1, further comprising retarding a flame in polyurethane foam with the aliphatic isocyanate.

3. The method of claim 1, wherein the polyurethane foam has an absence of halogenated flame retardants and inorganic fillers and phosphate-based flame retardants.

4. The method of claim 1, wherein the aliphatic isocyanate component is selected from an isocyanate component that contains one to five isocyanate compounds, these compounds are the same or different.

5. The method of claim 1, wherein the aliphatic polyisocyanate is selected from: hexamethylene diisocyanate (HDI), pentamethylene diisocyanate (PDI), isophorone diisocyanate (IPDI), 4,4′-diisocyanatodicyclohexylmethane (H12MDI) and 2,4,4-trimethylhexamethylene diisocyanate (TMDI).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] For the purpose of aiding the understanding of the characteristics of the invention, according to a preferred practical embodiment thereof and in order to complement this description, the following figures are attached as an integral part thereof, having an illustrative and non-limiting character:

[0021] FIG. 1 shows a comparative chromatographic profile corresponding to the analysed samples.

[0022] FIG. 2 shows a zoomed chromatographic profile between 2-6 min.

[0023] FIG. 3 shows a mass spectrum of peak at RT 1.39 min (N.sub.2O or CO.sub.2) and its comparison with NIST05 library.

[0024] FIG. 4 shows a mass spectrum of peak at RT 2.78 min (cyanogen) and its comparison with NIST05 library.

[0025] FIG. 5 shows a mass spectrum of peak at RT 3.47 min (propene) and its comparison with NIST05 library.

[0026] FIG. 6 shows a mass spectrum of peak at RT 4.20 min (methyl chloride) and its comparison with NIST05 library.

[0027] FIG. 7 shows a mass spectrum of peak at RT 4.35 min (Methylacetylene) and its comparison with NIST05 library

[0028] FIG. 8 shows a mass spectrum of peak at RT 4.73 min (Propadiene) and its comparison with NIST05 library.

[0029] FIG. 9 shows a flame test of the foam from the sample 2 used the Example 1 (left) versus the foam from the sample 3 used in the Example 1 (right).

DETAILED DESCRIPTION OF THE INVENTION

[0030] As mentioned above, the approach of the present invention relates to the use of aliphatic isocyanate as a fume toxic suppressant in polyurethane foam, wherein the aliphatic isocyanate component is included in polyurethane foam by reacting with at least one polyol compound.

[0031] The polyurethane foam has an absence of halogenated flame retardants and inorganic fillers and phosphate-based flame retardants.

[0032] The present invention also relates to the use of aliphatic isocyanate as a toxic fume suppressant and a flame retardant in polyurethane foam, wherein the aliphatic isocyanate component is included in the polyurethane foam by reacting with at least one polyol compound.

[0033] Preferably the isocyanate component is selected from an isocyanate component that contains one to five isocyanate compounds, these compounds are the same or different.

[0034] In a particular embodiment the aliphatic polyisocyanate is selected from: hexamethylene diisocyanate (HDI), pentamethylene diisocyanate (PDI), isophorone diisocyanate (IPDI), 4,4′-diisocyanatodicyclohexylmethane (H12MD1) and 2,4,4-trimethylhexamethylene diisocyanate (TMDI).

EXAMPLE 1

[0035] In the present Example three samples were analysed.

[0036] Sample 1 (aliphatic sample): fumes recollected after burning polyurethane foam obtained by reacting aliphatic polyisocyanate and polyol compounds. The aliphatic polyisocyanate used was pentamethylene diisocyanate (PDI). The polyol compounds were trifunctional polyether polyol based on glycerol (25%), difunctional polyether polyol based on 1,3-propanediol (5%), 1,4-butanediol (5%) and triethylenediamine (1%) as catalys. Also 0.2% of blowing agent (water) was added. The mixing ratio polyol/iso was b 65/35

[0037] Sample 2 (aromatic sample): fumes recollected after burning polyurethane foam obtained by reacting aromatic isocyanate and polyol compounds. The aromatic polyisocyanate used was diphenylmethane diisocyanate. trifunctional polyether polyol based on glycerol (10%), difunctional polyether polyol based on 1,3-propanediol (30%), 1,4-butanediol (10%) and triethylenediamine (0.5%) as catalyst. Also 0.2% of blowing agent (water) was added. The mixing ratio polyol/iso was 50/50.

[0038] Sample 3: (control): lab air room from where the combustion tests were performed.

[0039] Tests performed: Screening by GC/MS

[0040] Analytical methodology Sample preparation: direct introduction Analytical determination: Gas chromatography-mass spectrometry (GC/MS) Equipment used:

[0041] Column: SupelQ-Plot (30 m×0.32 mm)

[0042] Injector temperature: 200° C.

[0043] Mode: Split / Split ratio: 20:1/Injection volume: 0.6 ml

[0044] Temperature programme: 30° C. (6 min)@10° C./min until 120° C. (1 min)

[0045] Interface temperature: 250° C. / Ionization source temperature: 230° C.

[0046] Ionization mode: electron impact, SCAN mode (29-250 amu)

[0047] Instrumentation: Trace Gas chromatograph coupled to a DSQII mass spectrometer (ThermoFisher Scientific)

[0048] Carrier gas: Helium flow 1 ml/min

[0049] FIGS. 2-3 illustrates that the sample 2 (aromatic sample) shows the presence of peaks corresponding to propylene and propadiene, which are olefins (therefore extremely flammable and toxic per se). However, the sample 1 (aliphatic sample) does not show these peaks, clear evidence that the toxicity of smoke is lower as it does not contain such extremely flammable and toxic compounds.

[0050] The results showed by the gas chromatograph were confirmed by the mass spectrum.

[0051] The FIGS. 3-8 show the mas spectrum that confirm:

[0052] the peak at RT 1.39 min is N.sub.2O;

[0053] the peak at RT 2.78 min is cyanogen;

[0054] the peak at RT 3.47 min is propene;

[0055] the peak at RT 4.20 min is methyl chloride;

[0056] the peak at RT 4.35 min is Methylacetylene;

[0057] the peak at RT 4.73 min is propadiene.

[0058] Due to this it is confirmed that including aliphatic polyisocyanate in polyurethane foam implies that the foam is less flammable and with less spread to fire and also with much less toxicity in the absence of olefins (evidenced in GC-MS analysis).

[0059] FIG. 9 shows the foam of sample 2 (left) and the foam of sample 1 (right) burning. The aromatic foam shows high amount of dark smokes, that means toxic smoke and fast ignition. The foam of sample 1 (right) shows very low emission of white (non toxic) smoke and a retarded ignition.