| 摘要 |
PROBLEM TO BE SOLVED: To provide a rubber composition which emits reduced smoking and is free from irritant odors owing to the use of a non-halogen flame retardant, suppresses occurrence of dripping and exhibits excellent flame retardancy while maintaining mechanical characteristics inherent in the rubber by admixing a nitrilotris(methylene)phosphonic acid metal salt with a rubber component. SOLUTION: To 100 pts.wt. of a rubber component such as natural rubbers, styrene-butadiene rubbers, butyl rubbers, polybutadiene rubbers and the like are incorporated 3-20 pts.wt., in terms of phosphorus, of a nitrilotris(methylene) phosphonic acid metal salt obtained by reacting a nitrilotris(methylene) phosphonic acid and a salt thereof represented by the formula (wherein M1 and M2 are each H or an alkali metal) with a divalent metal compound to give a flame retardant rubber composition. Preferably, a hydrated metal oxide such as calcium hydroxide, magnesium hydroxide, basic magnesium carbonate, aluminum hydroxide 1nd the like are also added to be jointly used in an amount of 30-100 pts.wt. based on 100 pts.wt. of the rubber to this flame retardant composition.
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