Sprayable Silicone Polymer Dispersion

Abstract

A sprayable polymer dispersion includes (a) a room temperature vulcanizing (RTV) silicone polymer, (b) a polysiloxane, (c) an insulating agent and (d) an organic carrier in which components (a), (b), and (c) are suspended. Also included in the present invention is a method of producing a corrosion resistant coating on a substrate comprising spraying the polymeric dispersion onto at least a portion of a substrate and moisture curing each of components (a) and (b) to form a monolithic coating on the substrate, as well as a substrate at least partially coated with the sprayable polymer dispersion.

Claims

1. A sprayable polymer dispersion comprising: (a) a room temperature vulcanizing (RTV) silicone polymer; (b) a polysiloxane; (c) an insulating agent; and (d) an organic carrier in which components (a), (b), and (c) are suspended.

2. The dispersion of claim 1, wherein the organic carrier (d) comprises a blend of solvents, wherein the solvents are methyl ethyl ketone, methyl amyl ketone, xylene, toluene, mineral spirits, methyl acetate, cyclohexane, dimethyl carbonate, and/or parachlorobenzotrifluoride.

3. The dispersion of claim 1, wherein the insulating agent comprises microspheres.

4. The dispersion of claim 3, wherein the microspheres comprise a passivation agent.

5. The dispersion of claim 1, further comprising, in addition to components (a)-(d), a passivation agent selected from the following: magnesium oxide, zinc phosphate, metal-modified zinc phosphates, metal-modified phosphosilicate and/or metal-modified borosilicate, wherein the metal comprises calcium, barium, strontium, molybdenum, magnesium and/or aluminum.

6. The dispersion of claim 1, wherein the polysiloxane is substantially free of phenyl groups.

7. The dispersion of claim 1, wherein the polysiloxane is completely free of phenyl groups.

8. A method of producing a coating on a substrate comprising spraying the dispersion of claim 1 onto at least a portion of a substrate and curing of each components (a) and (b) to form a monolithic coating on the substrate.

9. The method of claim 8, wherein the monolithic coating is produced by spraying the dispersion in one pass over the substrate to produce a coating that is at least 100 mils thick.

10. The method of claim 8, wherein the monolithic coating is produced by spraying the dispersion in one pass over the substrate to produce a coating that is at least 500 mils thick.

11. The method of claim 9, wherein the dispersion is sprayed directly onto the substrate with no coating or treatment layer in between the substrate and the dispersion.

12. The method of claim 9, wherein the RTV polymer comprises a single component.

13. The method of claim 9, wherein the RTV polymer is produced from a two-part reaction mixture comprising a binder component and a crosslinking component.

14. A coating formed from the polymer dispersion of claim 1.

15. The coating of claim 14, wherein the coating is at least partially cured.

16. A substrate at least partially coated with the dispersion of claim 1 or a coating formed therefrom.

17. The substrate of claim 16, wherein the dispersion is moisture cured as a monolithic coating.

18. The substrate of claim 16, wherein the substrate is metal.

19. An industrial processing component comprising the substrate of claim 16.

20. The industrial processing component of claim 19, wherein the component comprises a reactor, exhaust stack, reformer, distillation column, piping, valve, heat exchanger, boiler or storage tank.

Description

EXAMPLES

[0026] Sprayable dispersions were prepared using the components of Tables 1-10 by adding the components sequentially as listed to a clean dry container under medium mixing using a cowles blade. Once all items were added to the container, they were mixed for 30-60 minutes or until completely homogenized. In Example 4, the components were added sequentially to a clean dry container under medium mixing using a cowles blade. Once all items were added to the container, they were mixed for 30-60 minutes or until completely homogenized. Item 10 was kept separate and added before application with medium mixing.

Comparative Example 1

[0027] A comparative dispersion was prepared using the components of Table 1.

TABLE-US-00001 TABLE 1 Material Weight (g) methyl ethyl ketone 50.49 mineral spirits 5.39 GENIOSIL XL-10.sup.1 1.96 ELASTOSIL E951.sup.2 15.69 ROCK FORCE MS603.sup.3 4.51 SPHERICEL 34P30.sup.4 13.33 ground cork.sup.5 (filler) 8.63 .sup.1Vinyl alkoxy silane available from Wacker Chemical Corporation (Adrian, MI) .sup.2RTV silicone polymer available from Wacker Chemical Corporation (Adrian, MI) .sup.3Mineral fiber available from Lapinus Fibres BV (Roermond, NL) .sup.4Hollow glass microspheres available from The Cary Company (Addison, IL) .sup.5Ground cork available from Jelinek Cork Group (Savannah, GA)

Comparative Example 2

[0028] A comparative dispersion was prepared using the components of Table 2.

TABLE-US-00002 TABLE 2 Material Weight ELASTOSIL E951 10.73 methyl ethyl ketone 36.06 DOWSIL 2405.sup.6 3.58 TYZOR TnBT.sup.7 .12 ROCK FORCE MS603 2.75 mineral spirits 3.79 GENIOSIL XL-10 2.75 calcium carbonate.sup.8 (filler) 39.89 .sup.6Silicone intermediate, available from Dow Corning Corporation (Midland, MI) .sup.7Titanate catalyst, available from Dorf Ketal Specialty Catalysts (Houston, TX) .sup.8Calcium carbonate, available from Sigma-Aldrich (St. Louis, MO)

Comparative Example 3

[0029] A dispersion with an RTV polymer and insulating agent was prepared using the components of Table 3.

TABLE-US-00003 TABLE 3 Material Weight (g) mineral spirits 4.13 GENIOSIL XL-10 1.97 methyl ethyl ketone 39.13 TYZOR TnBT 0.17 ELASTOSIL E951 20.56 BENTONE SD-2.sup.9 4.12 ROCK FORCE MS603 3.95 Q-CEL 7040S.sup.10 25.48 .sup.9Clay rheology modifier, available from Elementis Specialties (East Windsor NJ) .sup.10Hollow sodium silicate microspheres available from The Cary Company (Addison, IL)

Example 4

[0030] A dispersion with a 2K RTV polymer and alkoxy polysiloxane with insulating agent was prepared using the components of Table 4.

TABLE-US-00004 TABLE 4 Material Weight (g) methyl ethyl ketone 38.67 mineral spirits 4.08 DOWSIL 2405 5.08 GENIOSIL XL-10 1.95 TYZOR TnBT 0.16 BENTONE SD-2 4.07 ROCK FORCE MS603 3.9 ELASTOSIL M4444 US.sup.11 14.92 Q-CEL 7040S 25.18 Catalyst T77.sup.12 1.49 .sup.11RTV silicone polymer available from Wacker Chemical Corporation (Adrian, MI) .sup.12Titanate catalyst, available from Dorf Ketal Specialty Catalysts (Houston, TX)

Example 5

[0031] A dispersion was prepared using the components of Table 5.

TABLE-US-00005 TABLE 5 Material Weight (g) methyl amyl ketone 43.75 GENIOSIL XL-10 1.97 DOWSIL 2405 5.14 TYZOR TnBT 0.17 BENTONE SD-2 4.12 ROCK FORCE MS603 3.95 ELASTOSIL E951 15.42 Q-CEL 7040S 25.48

Example 6

[0032] A dispersion was prepared using the components of Table 6.

TABLE-US-00006 TABLE 6 Material Weight (g) toluene 43.75 GENIOSIL, XL-10 1.97 DOWSIL 2405 5.14 TYZOR TnBT 0.17 BENTONE SD-2 4.12 ROCKFORCE MS603 3.95 ELASTOSIL E951 15.42 Q-CEL 7040S 25.48

Example 7

[0033] A dispersion was prepared using the components of Table 7.

TABLE-US-00007 TABLE 7 Material Weight (g) methyl ethyl ketone 38.62 mineral spirits 4.02 GENIOSIL XL-10 1.92 DOWSIL 2405 5.02 TYZOR TnBT 0.16 BENTONE SD-2 1.86 ROCK FORCE MS603 3.85 HALOX SZP-391.sup.13 7.17 ELASTOSIL E951 15.03 SPHERICEL 34P30.sup.14 22.34 .sup.13Zinc phosphate corrosion inhibitor available from ICL Specialty Products Inc. (Hammond, IN) .sup.14Hollow borosilicate microspheres available from The Cary Company (Addison, IL)

Example 8

[0034] A dispersion was prepared using the components of Table 8.

TABLE-US-00008 TABLE 8 Material Weight (g) methyl ethyl ketone 42.43 mineral spirits 4.42 GENIOSIL XL-10 2.12 DOWSIL 2405 5.51 TYZOR TnBT 0.18 BENTONE SD-2 2.05 ROCK FORCE MS603 4.23 ELASTOSIL E951 16.52 EXTENDOSPHERES KLS-150.sup.15 22.51 .sup.15Aluminum silicate microspheres available from Kish Company Inc. (Mentor, OH)

Example 9

[0035] A dispersion was prepared using the components of Table 9.

TABLE-US-00009 TABLE 9 Material Weight (g) methyl ethyl ketone 39.74 mineral spirits 4.14 GENIOSIL XL-10 1.98 DOWSIL 2405 5.16 TYZOR TnBT 0.17 BENTONE SD-2 1.92 ROCK FORCE MS603 3.96 HALOX SZP-391 7.37 ELASTOSIL E951 15.46 EXTENDOSPHERES KLS-150 20.11

Example 10

[0036] A dispersion was prepared using the components of Table 10.

TABLE-US-00010 TABLE 10 Material Weight (g) methyl ethyl ketone 39.62 mineral spirits 4.13 DOWSIL 2405 5.14 GENIOSIL XL-10 1.97 TYZOR TnBT 0.17 BENTONE SD-2 4.12 ROCK FORCE MS603 3.95 ELASTOSIL E951 15.42 Q-CEL 7040S 25.48

Test Methods

[0037] High Film Build Determination

[0038] Samples were applied to 3.175 mm thick steel panels (blasted, 1-2 mil profile, degreased) at a dry film thickness of 2.5 mm (100 mils) via drawdown. After allowing to dry for 24 hours, the films were assessed for any signs of cracking or other visible signs of coating degradation as reported in Table 11. After coating, the panels were exposed to 260° C. using a hot plate. The panels were placed on a room temperature hot plate, then brought to temperature over a period of 30 minutes. Once at the target temperature, the panels were exposed continuously for 100 hours, after which they were allowed to cool naturally to ambient temperature and checked for cracking and blistering.

[0039] Corrosion Testing

[0040] Samples were applied to 100 mm×150 mm×3.175 mm thick steel panels (blasted, 1-2 mil profile, degreased) at a dry film thickness (DFT) of 2.5 mm via drawdown. Where formulations (Comparative Example 2, Example 5, and Example 6) did not allow for single coats of 2.5 mm DFT, multiple coats were applied to reach the target DFT, with 16-24 hours in between successive coats. One set of panels was allowed to dry at ambient conditions for 7 days, after which they were exposed to 260° C. temperatures on a hot plate for 100 hours. Observations were made of cracking, delamination, or blistering on heating. Another set of panels was allowed to dry at ambient conditions until test, at least 2 weeks.

[0041] The coatings were artificially damaged with a 10 mm long scribe to underlying substrate, and subsequently exposed to a corrosive environment for 1500 hours in accordance with ASTM B117. At the completion of the exposure period, the panels were allowed to dry at ambient conditions for 24 hours, then tested for adhesion strength according to ASTM D4541. Following this, the panels were stripped of coating and corrosion at scribe was measured in accordance with ASTM D1654 as reported in Table 12.

TABLE-US-00011 TABLE 11 High Build and Heat Stability Results Cracking at 100 mils Blistering Example DFT After Heating CE 1 No No CE 2 Yes No CE 3 No Yes Ex. 4 No No Ex. 5 Yes No Ex. 6 Yes No Ex. 7 No No Ex. 8 No No Ex. 9 No No Ex. 10 No No

TABLE-US-00012 TABLE 12 Average Scribe Creep readings, 1500 Hours B117 Example Ambient Only 500 F. Exposure CE 1 21.9 9.6 CE 2 30.9 15.4 CE 3 6.2 4.3 Ex. 4 3.1 3.9 Ex. 5 4.5 2.1 Ex. 6 5.5 8.1 Ex. 7 1.4 2.5 Ex. 8 11.1 2 Ex. 9 4.1 1.1 Ex. 10 4.1 2.8

[0042] It is to be appreciated that a combination of acceptable properties (film build and corrosion resistance) were found for the dispersions of Examples 4-10. Comparative Examples 1 and 2 lacked an insulating agent and exhibited poor corrosion resistance. Comparative Example 3 (no polysiloxane) failed heat stability testing. Example 8 exhibited slightly less resistance to corrosion (compared to Examples 4-7, 9, and 10) likely due to the lack of a corrosion inhibitor.

[0043] The dispersion of the present invention showed improved insulation properties in a single coating 500 mils thick as compared to other corrosion resistant coatings as summarized in Table 13.

TABLE-US-00013 TABLE 13 Coating No. of coating thickness passes to achieve Coating material (mils) thickness Example 10 500 1 Epoxy binder.sup.16 30 5 Acrylic aerogel.sup.17 20 75 Acrylic.sup.18 20 75 .sup.16CARBOLINE 551, available from Carboline Company (Euclid, OH) .sup.17TENEMEC 971, available from Tenemel Inc. (Kansas City, MO) .sup.18INDUSTRIAL-DTI, available from Mascoat Ltd. (Houston, TX)