Is it permissible to transfer some requirements of company projects managed by an employee to his own private company, while observing honesty and providing the best prices and services, knowing that the company is unaware of his partnership?

An agent is not permitted to supply goods to, or deal with, an entity in which they are employed without the knowledge and permission of the authorized party. This is because it is not permissible for an agent to deal with themselves in matters of buying, selling, or leasing, except with the permission of their principal. This is due to the conflict between their duty to seek the best interests of their principal and their desire for personal profit. Therefore, you must inform the company's management of your desire to import from a company in which you have a stake. If they grant you permission, then there is no objection; otherwise, you must refrain from doing so.