Fireproofing Cementitious Coating Composition

Abstract

The invention provides a composition having a bulk density of 0.8 g/cm.sup.3 or less comprising (a) 25-65 weight % of an inorganic binder comprising (i) 83 to 100 weight % of calcium aluminate cement, (ii) 0 to 14 weight % of calcium sulphate, (iii) 0 to 9 weight % of portland cement wherein the weight % of (i), (ii), (iii) is based on the sum of (i)+(ii)+(iii), (b) 0.5-15 weight % of one or more organic polymers, (c) 30-75 weight % of one or more inorganic fillers wherein the bulk density of the fillers is less than 0.5 g/cm.sup.3, wherein weight % is calculated on the total weight of all the non-volatile components in the composition.

Claims

1. A composition having a bulk density of 0.8 g/cm.sup.3 or less comprising: (a) 25-65 weight % of an inorganic binder comprising (i) 83 to 100 weight % of calcium aluminate cement, (ii) 0 to 14 weight % of calcium sulphate, (iii) 0 to 9 weight % of portland cement wherein the weight % of (i), (ii), (iii) is based on the sum of (i)+(ii)+(iii), (b) 0.5-15 weight % of one or more organic polymers, (c) 30-75 weight % of one or more inorganic fillers wherein the bulk density of the fillers is less than 0.5 g/cm.sup.3, wherein weight % is calculated on the total weight of all the non-volatile components in the composition.

2. The composition of claim 1 wherein the one or more organic polymers are polymers prepared from ethylenically unsaturated monomers or/and polyorganosiloxanes.

3. The composition of claim 2, wherein the one or more organic polymers are polymers prepared from ethylenically unsaturated monomers selected from one or more of the following: (meth)acrylate monomer(s), vinyl acetate monomer(s), vinyl aromatic monomer(s), vinyl halide monomer(s), vinyl alcohol monomer(s), vinyl ester monomer(s), acrylonitrile monomer(s), alkene monomer(s) containing one alkene bond, and polyene monomer(s) containing two or more alkene bonds.

4. The composition of claim 1, comprising 2 to 13 weight % of one or more polymers prepared from ethylenically unsaturated monomers of one or more polymers.

5. The composition of claim 1, wherein the one or more polymers are one or more polyorganosiloxanes, and wherein the composition comprises 0.5 to 10 weight % of the one or more polyorganosiloxanes.

6. The composition of claim 1, wherein the inorganic fillers are selected from mica, pumice, foamed glass, aerated concrete, perlites and vermiculites.

7. The composition of claim 1 comprising 30 to 50 percent by weight of the one or more inorganic fillers.

8. The composition of claim 1, wherein the percentage weight (weight %) of calcium aluminate cement in the inorganic binder ranges from 90 to 100 wt %, the percentage weight of calcium sulphate in the inorganic binder ranges from 0 to 9 wt %, and the percentage weight of Portland cement in the inorganic binder ranges from 0 to 4 weight %.

9. A coating composition comprising the composition of claim 1 and water.

10. A coated substrate coated with the coating composition of claim 9.

11. The coated substrate of claim 10, wherein the substrate is metal

12. The coated substrate of claim 11, wherein the substrate is steel.

13. The coated substrate of claim 10 wherein the coated substrate does not comprise a supportive mesh and/or pins.

14. A method of protecting a substrate from fire by coating the substrate with the coating composition of claim 9, and allowing the coating composition to form a coating.

15. The method of claim 14 which does not use a supporting mesh and/or pins.

16. The composition of claim 1, comprising 2 to 9 weight % of one or more polymers prepared from ethylenically unsaturated monomers of one or more polymers.

17. The composition of claim 1, wherein the one or more polymers are one or more polyorganosiloxanes, and wherein the composition comprises 0.5 to 4 weight % of the one or more polyorganosiloxanes.

18. The composition of claim 1, wherein the inorganic fillers are mica and vermiculite.

Description

EXAMPLES

[0076] The invention will be elucidated with reference to the following examples. These are intended to illustrate the invention but are not to be construed as limiting in any manner the scope thereof.

Preparation of Cement CompositionsExamples 1-9

[0077] To prepare compositions 1-9, the components listed in Table 1 were mixed together on a low speed with a flat bladed stirrer for 5 minutes to produce homogeneous dry-mix mixtures. The dry mix mixtures were then gradually mixed into water, at a weight ratio of 95 g (Water): 100 g (dry mix) to produce paste-like mortar coating compositions. Immediately after preparation of the coating compositions, the coatings were applied to steel panels or in molds as described in the tests below.

TABLE-US-00001 TABLE 1 Component Composition No # (weight %) 1 2 3 4 5* 6* 7* 8* 9* Mica (bulk density 11 11 11 11 11 11 11 11 11 of 200-350 g/L) Vermiculite (bulk 25 25 25 25 25 25 25 25 25 density of 93-135 g/L) Bermocoll M30 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 (AkzoNobel) Styrene acrylate 4 4 4 4 4 4 4 4 4 copolymer powder (FX7000 (Elotex)) Inorganic cement Calcium aluminate 59.8 56.8 53.8 50.8 47.8 47.8 50.8 0.0 41.8 cement.sup.1 Calcium sulphate.sup.2 0.0 3.0 3.0 6.0 9.0 6.0 9.0 0.0 9.0 Portland Cement.sup.3 0.0 0.0 3.0 3.0 3.0 6.0 0.0 59.8 9.0 Weight % is based on the total weight of all the non-volatile components in the composition .sup.1Ciment Fondue from Kerneos .sup.2Prestia 2500 from L'afarge .sup.3Mastercrete original (CEMII/A-LL 32.5R) from Blue Circle

[0078] Examples 1-4 are within the scope of the present invention. Examples 5-9 are not within the scope of the present invention and are provided for comparative information only.

Adhesion Testingan Accelerated Adhesion Test

[0079] The coating compositions of Examples 1 to 9 and three commercial Portland cement-based coating compositions were applied by trowel to grit-blasted steel panels. No mesh and pins were used to support the coatings. The coatings were allowed to cure for 28 days at 25 C. The coatings had a dry film thickness of 25 mm. The coated steel panels were then immersed in water at 25 C. and visually checked for adhesion to the substrate after 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks and 6 weeks

[0080] After a number of weeks, the coatings were found to completely delaminate from the steel panels. The time it took for the coating to completely delaminate from the steel panel is recorded in Table 2.

TABLE-US-00002 TABLE 2 Time until coating delaminated from the Example # Composition steel panel 1 6 weeks 2 6 weeks 3 5 weeks 4 6 weeks 5* 2 weeks 6* 1 weeks 7* 1 weeks 8* 2 weeks 9* 2 weeks Commercial Portland 3 weeks cement-based product 1* Commercial Portland 0 weeks - Coating had delaminated before it cement-based product 2* was immersed in water Commercial Portland 0 weeks - Coating had delaminated before it cement-based product 3* was immersed in water *Comparative Examples

[0081] As can be seen from Table 2, compositions 1-4 of the present invention had better adhesion to the steel panel compared to comparative examples 5-9 and substantially better adhesion compared to the commercially available Portland cement based products.

Furnace TestingHydrocarbon Fire Curve

[0082] Coating compositions 1, 2, 7 8 and a commercial Portland cement based product were applied by trowel to grit blasted steel panels primed with epoxy amine primer and allowed to cure for 28 days. The coatings had a dry film thickness of 35 mm. The fire performance of the coatings was tested by exposure to a time-temperature curve in accordance with standard method UL 1709hydrocarbon fire curve. The time the coated substrate took to heat up to 538 degrees C. (1000 F) was regarded as the Time-to-Failure of that coating.

[0083] The Time-to-Failure test results are provided in Table 3.

TABLE-US-00003 TABLE 3 Example Time to Failure (minutes) 1 129 2 128 7* 124 8* 116 Commercial Portland cement-based product 120 *Comparative Examples

[0084] Table 3 shows that coatings 1 and 2 have a better fire performance compared to comparative examples 7 and 8 and the commercial Portland cement based product.

Compressive Strength Testing Following 28 Days Prohesion Spray

[0085] Each of coating compositions 1 to 9 were poured into 1604040 mm triple gang prism molds (available from Impact Test Equipment Ltd) in order to prepare each coating composition, three prisms having dimensions 40 mm40 mm160 mm for testing. The prisms were left to cure overnight at 25 C./50% RH and removed from the molds the following morning. The prisms were left to fully cure for 28 days at 25 C./50% RH.

[0086] The prisms were then subjected to 28 days prohesion salt-spray testing in accordance with ASTM G85, in which the prisms, during the 28 day period, were subjected to repeating 1-hour salt-spray cycles and 1-hour drying cycles. In the dry cycle, the prisms were dried at 35 C. In the salt-spray cycle, the prisms were sprayed with 0.35% ammonium sulphate, 0.05% sodium chloride solution at 23 C.

[0087] After the 28-day prohesion salt-spray, the prisms were tested for compressive strength, whereby each block was placed between 2 plates and subjected to an applied force until fracture. The force at which the blocks fractured describes the compressive strength of the block. For each coating composition, there were three prisms which were tested to give 3 compressive strength values for each coating composition. The mean average of the compressive strength values for each coating composition is provided in Table 4 below.

TABLE-US-00004 TABLE 4 Example Mean Average Compressive Strength (MPa) 1 4.02 2 5.11 3 4.27 4 4.21 5* 3.67 6* 3.47 7* 3.85 8* 3.80 9* 3.46 *Comparative Examples

[0088] Table 4 shows that the coating compositions 1-4 of the present invention have superior compressive strength when compared to comparative examples 5-9.

Comparative ExampleExample A from FR 2 900 653

[0089] The formulation of Example A from FR 2 900 653 was prepared by mixing 46.00% calcium aluminate cement, 25.60% wollastonite, 17.60% ceramic microsperes and 10.8% perlite by high speed disperser. Water (approximately 50-60% of the weight of the powder) was added to this formulation until the mixture was the required thickness to apply. The material was cast onto 150*300*5 mm steel panels at a dry film thickness of 25 mm which had already been pre-coated with epoxy-amine primer. The material was allowed to cure a room temperature (about 20 C.). A frame was used to hold the material in place until it dried. After 24 hours it was observed that the cement had fully delaminated from the substrate. Due to delamination of the cured material from the substrate no fire testing, compressive strength testing or adhesion testing could be carried out.