Development of a permeation panel to test dermal protective clothing against sprayed coatings

Design, construct, and characterize an apparatus to evaluate dermal protective clothing for resistance to polymerizing materials. Specifically, we evaluated the permeation of the most common glove material used in automotive collision repair (0.10-0.13 mm or 4-5 mil latex) with representative isocyanate-containing clear coats. Our ultimate goal is to make informed recommendations on dermal protective materials to prevent isocyanate exposures and reduce the likelihood of occupational illness in automotive collision repair and other industries.

A novel permeation panel was developed to assess dermal protective clothing. With this apparatus, up to eight test materials may be evaluated under typical-spray application conditions. Solid collection media comprised of 1-(2-pyridyl)-piperazine (2-PP)-coated fiberglass filters or colorimetric SWYPE™ pads were placed behind test materials to capture permeants. The 2-PP-coated filters were subsequently analyzed using a modified OSHA42/PV2034 method. Color change in the SWYPEs provided an immediate field estimate of breakthrough time. In addition, Teflon filters were mounted proximal to the permeation cells to measure the mass of clear coat applied to the panel and to evaluate loading homogeneity. This study evaluated the permeation of isocyanates through 0.10-0.13 mm latex glove material at a fixed time (30 min post-spraying) and over a time course (6-91 min post-spraying).

Monomers 1,6-hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI) permeated through (0.10-0.13 mm) latex glove material under typical glove use conditions (30 min). The latex glove material exhibited immediate breakthrough, with a permeation rate of 2.9 ng min(-1) cm(-2). The oligomeric forms of HDI and IPDI did not permeate the latex glove material. The spray application at 71 ± 5 °F was fairly homogeneous (33.7 ± 8 mg weight of dry clear coat per 5 cm(2)).

The permeation panel is a viable method to assess dermal protective clothing performance against polymerizing materials. Thin (0.10-0.13 mm) latex gloves were determined to be ineffective barriers to the isocyanates commonly found in clear coats. Because this type of glove is used frequently in auto body shops, the potential for isocyanate exposure is of concern. Permeation tests with other dermal protective clothing materials and other clear coat formulations are needed to make recommendations about alternative materials.