For whom did Solomon write Proverbs? Is there anything in Scripture or Hebrew historical documents that says for whom Proverbs was written? Did Solomon expect his sons to read them or were they for the people of Israel? Please provide verses or documents to support your claims.
Proverbs 1:4-5 tells us his audience:


  4 for giving prudence to those who are simple, knowledge and
  discretion to the young— 5 let the wise listen and add to their
  learning, and let the discerning get guidance—


They were written to the "simple," which the NIV defines as "The Hebrew word rendered simple in Proverbs denotes a person who is gullible, without moral direction and inclined to evil." They are also directed to the "young," "wise," and "discerning." 

In 2:1, 3:1, 6:1, 7:1, Solomon addresses "My son," and in 4:1, "Hear, my children" (or "sons," depending on the translation). 

Chapter 30 includes proverbs written by "Agur the son of Jakeh," and were declared to "Ithiel and Ucal" (30:1).

Chapter 31 was written by "King Lemuel" (31:1) and he addresses "my son" (31:2) and kings and princes (31:4).