Unsecured business loans are one of the most popular types of loans for small businesses. Unlike loans from banks, which are usually secured by collateral that you put up as the business, that will be seized in time of default, unsecured loans have no collateral behind them.
Although, these loans are safe in term so of having nothing behind them (asset wise), the cost when referring to interest rates is higher. Unsecured business loans usually have a shorter terms, under a year.
Unsecured business loans are good for working capital needs and any short term projects, that are seasonal or expansion related. Lendertip has a thorough guide on unsecured business loans.