MANILA, Dec 8 (Reuters) - Five firms submitted offers at a Philippine import tender for 600,000 tonnes of rice on Tuesday, the second tender for the same volume this month as the world's biggest rice buyer covers 2010 supplies.  The bidders were Vietnam's largest rice exporter Vinafood 2, Toepfer International, Daewoo International, Capital Cereals Co Ltd, and Chaiyaporn Rice Company Limited.   The rice is for delivery between February and May 2010.