the moment后面为何不需要when

Yes,abundance of love,warmly expressed from the moment he is put to his mothers breast.

the moment这里是做名词还是连词啊？感觉像是做名词，但又没加when,请教老师谢谢！

Yes, abundance of love, warmly expressed from the moment he is put to his mothers breast.

the moment为介词from的宾语，只能是名词，如何能是连词呢？想到连词都是不应该的。the momnet为时间名词，后接定语从句时，关系副词that常被省略。