same commercial shingles although asphalt coated on both sides employ a much greater asphalt coating thickness on one side than the other this test is compared to those conducted on samples prepared under the same conditions but for the replacement of the abs copolymer with a conventional urea formaldhyde modifier styrene butadiene rubber sbr the results of this test are summarized in table 2 example 1 was repeated but for the concentration of the abs modifier employed in the manufacture of the composite sheets of urea formaldehyde reinforced by glass fibers in this example the urea formaldehyde was modified by 10 by weight based on the total weight of the resin binder solids of hycar u00ae g 17 the percentage was by weight based on the weight of the urea formaldehyde binder the tensile strength of the ply sheets is reported in table 1 this test is compared to those conducted on samples prepared under the same conditions but for the replacement of the abs copolymer with a conventional urea formaldehyde modifier styrene butadiene rubber sbr the results of this test are summarized in table 2 example 2 was duplicated but for the concentration of the abs hycar u00ae g 17 modifier in this example the abs was present in a concentration of 20 by weight based on the weight of the urea formaldehyde binder the results of example 3 are reported in the table 1 these tests are compared to those conducted on samples.