Container cap and container combined with same

A container assembly comprising:

• a container body containing contents and having a container inlet;
• and
• a container cap combined with the container inlet,
• wherein a plurality of contact portions are formed on at least one of the container cap and the container inlet, and
• the plurality of contact portions form a closed curve enclosing the container inlet so as to block inflow of external air from outside into the container body,
• wherein the container cap comprises:
• a body part in close contact with an upper end of the container inlet;
• a sidewall part which extends downward from the body part and in which a female screw part that is screw-coupled with a male screw part formed on an outer circumferential surface of the container inlet is formed;
• and
• an inner ring protruding from a bottom surface of the body part and inserted into an inner circumferential surface of the container inlet, and
• wherein the container inlet includes an inner upper end and an outer upper end, each having a curved outer circumferential surface, a recessed groove being formed between the inner upper end and the outer upper end,
• wherein an inclined surface is formed on the container cap, the inclined surface including a first inclined surface and a second inclined surface, the first inclined surface being in contact with the curved outer circumferential surface of the inner upper end and the second inclined surface being in contact with the curved outer circumferential surface of the outer upper end when the container cap is combined with the container inlet,
• wherein an inner circumferential protruding part is formed on the inner circumferential surface of the container inlet, and the inner circumferential protruding part protrudes toward the inner ring to contact an outer circumferential surface of the inner ring when the container cap is combined with the container inlet,
• wherein the inner circumferential protruding part has a curved shape so that a cross-section in the longitudinal direction of the container inlet is in surface-contact with the outer circumferential surface of the inner ring,
• wherein a middle ring is formed on a bottom surface of the body part of the container cap, the middle ring being inserted into the recessed groove formed between the inner upper end and the outer upper end, the middle ring forming at least one close contact portion with the container inlet when the container cap is combined with the container inlet, a bottom of the middle ring being positioned above and spaced apart from a surface defining a bottom of the recessed groove, creating a gap therebetween, and
• wherein each of the inner upper end and the outer upper end has a structure inclined at a portion in which the recessed groove is formed and having elasticity.