slasi -las- gismu

x1 is a quantity of/is made of/contains plastic/polymer of type/component unit(s) x2.

See also rutni, boxfo, bukpu.

In notes:

boxfo
x1 is a sheet/foil/blanket [2-dimensional shape/form flexible in 3 dimensions] of material x2.
bukpu
x1 is an amount of cloth/fabric of type/material x2.
rutni
x1 is an artifact; x1 is artificial; x1 is made/caused by people/se kulnu x2; x1 is man-made.
klupanido
x1 is an occlupanid of species x2.