April 14. A Swedish manufacturer of plastic compounds is investing nearly $12 million in a new plant in Gastonia, creating 22 new jobs. New positions at Polykemi AB include operations, maintenance, finance and managerial personnel. The average annual salary is $59,132, compared to Gaston County’s average annual wage of $42,018. Polykemi provides custom plastic compounds for the automotive, furniture and household industries. The One North Carolina Fund assisted Polykemi’s expansion to North Carolina with a $50,000 grant.