UNION CITY, Ga. (AP) — A company that makes plastic mailers will open a factory in suburban Atlanta, investing $47 million and hiring 400 people. Seattle-based PAC Worldwide announced Thursday that it will open the plant in Union City this summer. PAC Worldwide President Steve Foster says the privately-held company is opening the factory to be closer to customers and suppliers. The 46-year-old company says expansion is driven in part by growth in online shopping. PAC Worldwide makes plastic envelopes, bubble wrap, and insulators for shipping. It also makes machines that wrap items. The state will pay to train workers and PAC Worldwide could qualify for more than $2.5 billion in state income tax credits.