BANGKOK, Thailand (Oct. 22)—The International Rubber Co. Ltd.—the joint venture consortium between Thailand, Malaysia and Indonesia to prop up natural rubber prices on the world market—is scheduled to start business Nov. 15, according to Thai officials. The announcement came as NR prices sagged from the four-year highs they reached last month. Standard Indonesian Rubber 20 is now at 41¼ cents per pound, down from 48 cents six weeks ago, and rubber smoked sheets fell from 48½ to 45 cents in a month's time on the New York market. Rubber prices in Thailand are hovering just above 30 baht, or about 70 cents, per kilogram. Thailand has earmarked $4.6 million, over and above its contribution to the consortium, to buy up rubber from Thai farmers if prices fall below the 30-baht level, according to rubber traders and Far East news sources.