I was a panel member advising Dr Blow in the mid 60s and good as his book was I'm afraid it, and the 1982 revision with Hepburn, are now well out of date, and there wasn't that much on product manufacture. Perhaps the best book around is Rubber Products Manufacturing Technology, edited by A K Bhowmick in 1994 - you can find individual contributions around the internet. Trouble is the volume is hellishly expensive even second hand. A more modest primer I can recommend is Andrew Ciesielski's An Introduction to Rubber Technology published in 1999. For more recent work have a look at the book section on the Smithers Rapra website. Some publications of a practical nature are also coming out in India but I haven't been able to see any detail.