SILICONE MEMBRANES

1 . A silicone roofing membrane comprising:

(i) a substrate; and

(ii) a silicone composition coating at least a portion of the substrate, wherein the substrate is a mesh or fabric, and wherein the silicone composition comprises a cross-linked polysiloxane.

2 . The membrane of claim 1 , wherein the silicone composition further comprises a catalyst, a surfactant, a pH-adjuster, a filler, a pigment, or any combination thereof.

3 . The membrane of claim 2 , wherein the silicone composition is derived from an aqueous emulsion comprising a pre-crosslinked polysiloxane.

4 . The membrane of claim 1 , wherein the silicone composition is derived from an emulsion comprising:

(a) 40 to 60 wt % of a hydroxyl-terminated polysiloxane;

(b) 1 to 3 wt % of a crosslinker;

(c) 0.1 to 1 wt % of a catalyst;

(d) 1 to 3 wt % of a surfactant; and

(e) 40 to 60 wt % water;

wherein wt % is based on total weight of the composition.

5 . The membrane of claim 4 , wherein the hydroxyl-terminated polysiloxane has a viscosity of 20,000 to 300,000 cps.

6 . The membrane of claim 4 , wherein the crosslinker is an alkoxy silane, an oxime silane, or an acetoxy silane.

7 . The membrane of claim 4 , wherein the crosslinker is methyltrimethoxysilane or aminopropyltrimethoxysilane.

8 . The membrane of claim 4 , wherein the catalyst is dimethyltin dineodecanoate, dibutyl tin dilaurate, or stannous octoate.

9 . The membrane of claim 4 , wherein the surfactant is 3-(polyoxyethylene)propylheptamethyltrisiloxane.

10 . The membrane of claim 4 , wherein the emulsion further comprises a pH-adjuster (e.g., 2-amino-2-methyl-1-propanol).

11 . The membrane of claim 4 , wherein the emulsion further comprises a filler.

12 . The membrane of claim 4 , wherein the emulsion further comprises a pigment.

13 . An emulsion for preparing a silicone membrane, comprising:

(i) 40 to 60 wt % of a hydroxyl-terminated polysiloxane;

(ii) 1 to 3 wt % of a crosslinker;

(iii) 0.1 to 1 wt % of a catalyst;

(iv) 1 to 3 wt % of a surfactant; and

(v) 40 to 60 wt % water;

wherein wt % is based on total weight of the composition.

14 . A method of preparing an emulsion useful for the manufacture of silicone membranes, the method comprising:

(i) mixing a hydroxyl-terminated polysiloxane, a crosslinker, and a catalyst, to provide a first mixture;

(ii) mixing a surfactant and water to provide a second mixture; and

(iii) combining and mixing the first and second mixtures to provide an emulsion.

15 . The method of claim 14 , wherein the emulsion is a high solids transparent gel structure.

16 . The method of claim 15 , further comprising of diluting the mixture with water to a solid contents of about 50 wt %.

17 . The method of claim 16 , comprising:

(a) mixing (i) 40 to 60 wt % of the hydroxyl-terminated polysiloxane, (ii) 1 to 3 wt % of the crosslinker, and (iii) 0.1 to 1 wt % of the catalyst, to provide the first mixture; and

(b) mixing (iv) 1 to 3 wt % of the surfactant, and (v) and about equal portion of water, to provide the second mixture.