The all 15 UN Security Council members, including China, approved a resolution condemning North Korea's launch of a long-range rocket. Most members of the UN countries seem to want strong sanctions on North Korea, but China would not want that strong measures. They might be afraid of confusion in North Korea after that. That would be one of a Kim's plans, though.
Sooner or later, it will happen. The Kim monarchy will collapse someday. Chinese communist government is afraid of the influence, like Arab Springs.