Non-black rubber membranes

1. A process for preparing a roofing membrane, the method comprising:

i. mixing ethylene-propylene-diene rubber, silica, and a coupling agent defined by the formula:

where R 8 is a divalent organic group or a bond, R 9 is a halogen atom or an alkoxy group, and each R 10 is independently a halogen, an alkoxy group, or a monovalent organic group, and where R 11 is a blocking group to form a mixture, where the mixture is devoid of carbon black;

ii. adding a curative to the mixture to form a vulcanizable rubber composition;

iii. fabricating the vulcanizable composition into an uncured sheet; and

iv. curing the uncured sheet.

2. The process of claim 1 , further comprising the step of introducing ethylene-propylene-diene rubber with a coupling agent, where the coupling agent is dispersed in a carrier.

3. The process of claim 1 , where the curative is sulfur or a sulfur-containing compound.

4. The process of claim 3 , further comprising the step of adding a cure accelerator.

5. The process of claim 1 , where the coupling agent is a thioester, a thiophosphinate, a thiophosphate, or a thiosulphonate.

6. The process of claim 1 , where the mixture includes at least 30 and less than 120 parts by weight processing oil per 100 parts by weight rubber.

7. The process of claim 6 , where the processing oil has a sulfur content of less than 0.5 weight percent and an unsaturation level of less than 3%.

8. The process of claim 1 , where the vulcanizable composition includes:

i. an ethylene-propylene-diene rubber;

ii. from about 20 to about 250 parts by weight of a silica filler per 100 parts by weight rubber; and

iii. from about 0.1 to about 5 parts by weight of a silane coupling agent per 100 parts by weight rubber; wherein the silane coupling agent is compatible with both the ethylene-propylene-diene rubber and the silica filler such that the ethylene-propylene-diene rubber is chemically coupled to the silica filler.