Patent attributes
The present invention provides an oxygen absorber which exhibits a high oxygen-absorbing ability even if a transition metal salt as a catalyst for making oxygen-absorbing ability high is not added thereto and further keeps a high mechanical strength even after the absorber absorbs oxygen. An oxygen absorber containing a cyclized conjugated diene polymer as an active ingredient. About the cyclized conjugated diene polymer, the percent decrease in unsaturated-bond amount is preferably 10% or more and the weight-average molecular weight preferably ranges 1,000 to 1,000,000. The oxygen absorber may further contain a thermoplastic resin. The content of an antioxidant in the oxygen absorber is preferably 500 ppm or lower. The oxygen absorber is in a film, sheet or powder form.