I claim the ornamental design for a polyurethane foam gun, as shown and described.
FIG. 1 shows a perspective view of a polyurethane foam gun;
FIG. 2 shows a front elevational view of FIG. 1;
FIG. 3 shows a left side elevational view of FIG. 1;
FIG. 4 shows a back elevational view of FIG. 1;
FIG. 5 shows a right side elevational view of FIG. 1;
FIG. 6 shows a top plan view of FIG. 1; and,
FIG. 7 shows a bottom view of FIG. 1.
The broken line showing of the polyurethane foam gun is included for the purpose of illustrating portions of the article and forms no part of the claimed design.