| 摘要 |
PROBLEM TO BE SOLVED: To obtain a light-gage and compact cap for a lamp which is improved in transparency, heat resistance, long-term stability and light resistance by forming the cap for the lamp which covers part or all of the lamp from an alicyclic structure-containing polymer resin. SOLUTION: As a polymer resin having an alicyclic structure, for balancing heat resistance, mechanical strength and molding processability, a hydrogenated ring-opening polymer and its addition polymer of a norbornene monomer, an addition polymer of a norbornene monomer and a copolymerizable vinyl compound or the like is preferable. As a monomer, bicyclo(2,2,1)hept-2-ene, bicyclo(4,3,0)nonene, ethylene, 1-hexene or the like is cited. A resin is that in molding it, heat decomposition, hydrolysis and foaming do not occur and besides that in melting it, flow properties are good, and a light-gage molding is obtained. Further, even if an obtained cap for a lamp was exposed to heat and light from the lamp for the long-term, aging changes such as yellowing or the like do not occu. A light implement with the cap for a lamp used is provided.
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