Characterization and exposure assessment of odor emissions from laser cutting of plastics in the optical film industry

Abstract

The introduction of lasers as a cutting tool has become an important step in achieving further cost reductions in the multi-functional optical film industry. However, the fumes produced during laser cutting causes an annoying and often unbearable odor in the working environment. To date, little research has been reported in terms of the worker exposure assessment and odorous substances generated in the process of cutting plastics with lasers. This study firstly investigated the worker exposure assessment and the protection efficiency of the carbonyls and phenols when a laser is used to cut polycarbonate (PC) and polyethylene terephthalate (PET), the primary base materials used in optical film industry. Results indicate that the concentrations of these substances increased with the power of the laser. Due to differences in the monomer structures of these materials, a 240 W laser produced a high concentration of phenols (1.56 mg m-3) from PC and a high concentration of carbonyls (20.3 mg m-3) from PET. Without adequate protection and within a one-meter distance, laser cutting PET at the 240 W power level would expose machine operators to 2.74 mg m-3 of formaldehyde, which exceeds the regulatory standard of 2.4 mg m-3. An N95 valved active carbon respirator can effectively reduce this concentration to 0.07 mg m-3. However, the result of the masks studies could only reduce concentrations to between 1.88 mg m-3 and 2.2 mg m-3, which barely meet the related regulatory standards. In contrast, the installation of local ventilation alone can effectively remove as much as 99% of the gaseous substances produced in the laser cutting of plastics.