Elastomeric compositions and their applications

Patent metadata

Field	Value
Publication number	US-10844177-B2
Application number	US-201716322639-A
Country	US
Kind code	B2
Filing date	Aug 3, 2017
Priority date	Aug 3, 2016
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

The present disclosure relates to self-sealing silicone sealant and/or gel compositions cured via a condensation cure chemistry and to their use subsequent to cure as puncture-resistant layers in any type of “inflatable” article, i.e. articles which take their functional shape after inflation with a suitable gas such as air. The present disclosure also relates to silicone materials, e.g. elastomers and/or gels obtained subsequent to curing said compositions designed to function as self-sealing tire puncture material, i.e. to seal puncture holes in the tread region of tires if/when punctured by a foreign body.

First claim

The invention claimed is:

1. A multi-part self-sealing moisture curing silicone sealant composition comprising:
(i) at least one condensation curable silyl terminated polymer having at least one, optionally at least 2 hydroxyl functional groups per molecule;
(ii) a cross-linker selected from the group consisting of;
silanes having at least 2 hydrolysable groups, optionally at least 3 hydrolysable groups per molecule, and/or
silyl functional molecules having at least 2 silyl groups, each silyl group containing at least one hydrolysable group;
(iii) a condensation catalyst selected from the group consisting of titanates and/or zirconates; and
(iv) a filler;
wherein polymer (i), cross-linker (ii) and condensation catalyst (iii) are not stored together in a single part; and
wherein the molar ratio of total silicon-bonded hydroxyl groups to total hydrolysable groups is between 0.5:1 and 2:1 using a silane containing cross-linker (ii) or 0.5:1 to 10:1 using a silyl functional molecule containing cross-linker (ii) and the molar ratio of condensation catalyst (iii) M-OR functions to the sum of moisture present in the composition, as determined in accordance with ISO 787-2:1981, and total silicon-bonded hydroxyl groups is between 0.01:1 and 0.6:1, where M is titanium or zirconium and R is an aliphatic hydrocarbon group.

2. The multi-part self-sealing moisture curing silicone sealant composition in accordance with claim 1 , wherein the viscosity of the polymer (i) and the cross-linker (ii) when mixed at 23° C. is at least 40,000 mPa·s.

3. The multi-part self-sealing moisture curing silicone sealant composition in accordance with claim 1 , wherein the filler (iv) is selected from the group consisting of fumed and precipitated silicas, calcium carbonate, carbon black, hollow glass beads and/or carbon nanotubes.

4. The multi-part self-sealing moisture curing silicone sealant composition in accordance with claim 3 , wherein the filler (iv) is multiwall carbon nanotubes and/or is carbon black.

5. The multi-part self-sealing moisture curing silicone sealant composition in accordance with claim 1 , wherein the molar ratio of total silicon-bonded hydroxyl groups to total hydrolysable groups is between 1:1 and 2:1.

6. The multi-part self-sealing moisture curing silicone sealant composition in accordance with claim 1 , wherein the composition is stored in two parts, a base part comprising polymer (i) and filler (iv), and a curing part comprising cross-linker (ii) and condensation catalyst (iii).

7. The multi-part self-sealing moisture curing silicone sealant composition in accordance with claim 1 , wherein polymer (i) has at least 2 hydroxyl functional groups per molecule.

8. The multi-part self-sealing moisture curing silicone sealant composition in accordance with claim 1 , wherein cross-linker (ii) is selected from the group consisting of silanes having at least 3 hydrolysable groups per molecule.

9. The multi-part self-sealing moisture curing silicone sealant composition in accordance with claim 1 , wherein the filler (iv) contains moisture.

10. The multi-part self-sealing moisture curing silicone sealant composition in accordance with claim 1 , wherein the condensation catalyst (iii) comprises a titanate.

11. The multi-part self-sealing moisture curing silicone sealant composition in accordance with claim 10 , wherein the titanate is of the general formula Ti[OR] 4 where R is an aliphatic hydrocarbon group.

12. A moisture cured self-sealing silicone sealant for an inflatable article comprising the condensation reaction product of the multi-part self-sealing moisture curing silicone sealant composition in accordance with claim 1 .

13. A self-sealing inflatable article comprising the moisture cured self-sealing silicone sealant in accordance with claim 12 .

14. The self-sealing inflatable article in accordance with claim 13 which is in the form of a tire.

15. The self-sealing inflatable article in accordance with claim 14 comprising:
a) a tire body that is made of flexible and airtight material and is adapted to be assembled with a rim; and
b) the moisture cured self-sealing silicone sealant adapted to seal a puncture in the tire body.

16. The self-sealing inflatable article in accordance with claim 13 having a puncture-resistant layer, wherein the puncture-resistant layer is a layer of the moisture cured self-sealing silicone sealant.

17. The self-sealing inflatable article according to claim 16 , wherein the puncture-resistant layer has a thickness of greater than 0.3 mm.

18. The self-sealing inflatable article according to claim 17 , wherein the puncture-resistant layer has a thickness of between 0.5 mm and 10 mm.

19. The self-sealing inflatable article according to claim 16 , wherein the puncture-resistant layer is positioned on an internal wall of the inflatable article.

20. A self-sealing tire comprising the condensation reaction product of the multi-part self-sealing moisture curing silicone sealant composition in accordance with claim 1 .

Assignees

• Dow Silicones Corp

Inventors

• Baily Victor
• Chambard Gregory
• Gubbels Frederic

Classifications

• C09K3/1018

  Macromolecular compounds having one or more carbon-to-silicon linkages · CPC title

• C08G77/08

  characterised by the catalysts used · CPC title

• C08G77/16

  to hydroxy groups · CPC title

• C08K3/36

  Silica · CPC title

• C08L83/04 Primary

  Polysiloxanes · CPC title