asphalt roofing materials , including shingles , are manufactured by following conventional procedures . bituminous prepared roofing has heretofore been extensively manufactured using as a base a fibrous web such as a sheet of roofing felt or fiberglass mat , impregnating the fibrous web with a bituminous material and coating one or both surfaces of the impregnated web with a weather - resistant bituminous coating material . the bituminous coating material usually contains a mineral filler such as slate flour or powdered limestone . sometimes one or more fibrous sheets are laminated with one or more bituminous layers . usually there is applied to the bituminous coating on the surface intended to be exposed to the weather a suitable granular material such as slate granules or mineral surfacing . finely divided materials such as mica flakes , talc , silica dust or the like may be made adherent to the non - weather exposed surface of the roofing shingle to prevent sticking of the adjacent layers of the roofing material in packages . in the present invention , the fines on the back of roofing material are replaced with a backing material or mat that renders the product more energy absorbent than it otherwise would be . in a preferred embodiment , the mat includes a non - woven layer of wet laid polyester staple fibers . however , a woven polyester mat may also be employed . polyester mats are resistant to punctures and tears and thus , their inclusion on the backs of roofing materials renders the materials less susceptible to damage from hail . the backing material is adhered to the face of the back of the shingle in lieu of fines , granules or other standard backing material at the slating drum stage of conventional shingle manufacturing . the inventive shingles are manufactured using a standard line where asphalt coats the moving web and mineral granules are dropped on the upper surface of the hot asphalt coated web . in accordance with the invention , a roll of mat enters from the back side of the line at 90 °. the roll runs through an unwind stand , a splicer , an accumulator , and directional changing rolls to feed the mat under the slating drum . alternatively , the mat may enter from the top and be fed directly to the back of the slating drum , in essence replacing the back surfacing equipment normally utilized . the application technique is similar to the current industry technique of applying release tape to the back of the shingle at the slating drum . polyester melts at approximately 350 ° f . and the asphalt which coats the moving web in shingle manufacturing is typically about 400 ° f . thus , the polyester fuses to the back of the shingle . however , because cooling occurs rapidly , the back side of the polyester mat facing away from the shingle remains intact . shingles made with the inventive polyester backing have better tear strength than standard shingles backed with finely divided granules . the inventive shingles are less susceptible to machine breaks and fractures and tears during field application , i . e . they tolerate installation abuse . further , the inventive shingles pass impact tests despite their light product weight . moreover , they demonstrate increased nail holding ability and maintain structural integrity at elevated temperatures . also , the mat fused to the back of the shingle is less likely to crack than the asphalt coating . thus an enhanced impact resistant seal against water penetration is provided . additionally , the mat adheres readily to the sealant ( usually a compounded bituminous material such as those disclosed in u . s . pat . no . 4 , 559 , 267 ) superposed on at least some portion of the roofing material to prevent blow offs . the inventive backing may be applied to any design or formulation of roofing material such as built up roofing materials , roll roofing and modified roll products , but it is particularly effective as shingle backing . as heretofore noted , a variety of materials may be employed in providing the backing of the inventive roofing materials . such backing material , which may provide partial or full coverage of the lower surface of the shingles , enables the shingles to demonstrate enhanced physical properties even though the internal composition of the shingle remains unchanged . regarding handlability , the exposed portion of the inventive shingle feels more substantial compared to the conventional product . the inventive roofing material is pliable at cold temperatures but not limp at hot temperatures . in accordance with the invention , backing material was prepared by combining fiber and binder such that the fiber component comprised 78 % by weight of the material and the binder component comprised 22 % by weight of the material . however the fiber component may comprise from about 65 % to about 92 % of the backing material and the binder component may comprise from about 35 % to about 8 % of the backing material . elk &# 39 ; s corporation standard polyester blend containing equal weights of 1 . 5 denier 0 . 25 inch and 0 . 50 inch polyester fiber comprised 90 % of the fiber component and woodpulp made up the remaining 10 %. the binder component was approximately 89 . 5 % bf goodrich 26138 latex binder , approximately 10 % cymel 373 crosslinking agent which may be obtained from cytec industries of west patterson , n . j . and approximately 0 . 5 % citric acid . polyester fibers may comprise from about 70 % to about 95 % of the fiber component and woodpulp may comprise from about 0 % to about 30 % of the fiber component . a binder material , such as a latex binder , may comprise from about 83 % to about 100 % of the binder component , crosslinking agent may comprise from about 0 % to about 15 % of the binder component and citric acid may comprise from about 0 % to about 2 % of the binder component . having learned from unrelated work that 15 denier 1 . 50 inch polyester fiber results in increased mat tear strength , it was thought that a major portion of the standard polyester fiber blend could be replaced with less costly glass fiber if a low percentage of 15 denier 1 . 50 inch polyester were added to maintain tear strength . additionally , it was believed that such a fiber formulation would require less binder component and a lower cost binder material . several formulas were evaluated in laboratory handsheets . larger diameter glass fibers provided lower costs and better mat tear strength , but increased mat porosity resulted in unacceptable penetration of hot asphalt through the mat . a 1 . 05 lb . handsheet mat containing a furnish of 60 % 0 . 50 inch h - 9501 glass fiber obtained from owens corning , 30 % standard polyester blend obtained from celanese and 10 % 15 denier 1 . 50 inch polyester obtained from combined with rohm & amp ; haas gl - 618 latex binder was found to provide the most favorable strength : penetration : cost balance . the fiber component comprised about 82 % of the backing material and the binder component was about 18 %. polyester fibers may comprise from about 5 % to about 95 %, of the fiber component and glass fibers may comprise from about w / o to about 5 % of the fiber component . although a crosslinking agent and citric acid were not included in this example , their inclusion may be appropriate in certain glass fiber / polyester formulations a . 0 depending on the desired tensile and tear strengths of the product . in such formulations , binder material may comprise from about 83 % to about 100 % of the binder component , crosslinking agent may comprise from about 0 % to about 15 % of the binder component and citric acid may comprise from about 0 % to about 2 % of the binder component . experimental data obtained for example i , example ii and a standard laminated shingle product sold by elk are provided in table i below : table i mat shingle example i example ii example i example ii c standard product basis weight ( lb / sq ) 1 . 05 1 . 09 thickness ( mil ) 13 23 frazier porosity ( cfm / ft 2 ) 268 638 tensile 3 ″( lb ) md & amp ; cd avg . 57 58 md 119 113 87 cd 59 67 48 hot wet tensile ( 3 ″) 180 ° f . 36 51 md elmendorf tear ( g ) md & amp ; cd 385 356 md 1653 1547 1144 cd 2222 2335 1571 taber stiffness ( g - cm ) md & amp ; cd 57 64 binder content (%) 22 a 16 b table ii below provides a relative comparison between elk &# 39 ; s standard p2 shingle product ( for which data are presented in table i ), elk &# 39 ; s heavier standard wisconsin p2 shingle and two inventive wisc . p2 shingles of the present application , one made with a 1 . 05 lb ./ square backing material of example i and the other made with a 1 . 25 lb ./ square backing material of example i . backing material adhered to roofing material in accordance with this invention may range from 0 . 50 lb ./ sq . to 5 . 0 lb / sq . elk &# 39 ; s standard p2 shingle is offered as a control with all values shown as 1 . the values presented for the other products are all shown as relative to the p2 shingle control . thus , inventive wisc . p2 with a 1 . 05 lb ./ sq . polyester based backing material has an md ( machine direction ) tensile value which is 1 . 84 times the value of the standard p2 shingle and a cd ( cross direction ) tensile value which is 1 . 79 times the value of the standard p2 shingle . the data demonstrate that , by employing the inventive polyester based backing , superior properties were achieved relative to heavier weight products having essentially the same asphalt coating formulation . table ii wisc . p - 2 wisc . p - 2 reg . p - 2 wisc . p - 2 w / 1 . 05 / lb . w / 1 . 25 / lb . control std . polyester polyester tensile md 1 1 . 34 1 . 84 1 . 79 cd 1 1 . 39 1 . 79 1 . 79 tear md 1 1 . 12 1 . 62 1 . 47 cd 1 1 . 43 2 . 02 1 . 91 nail pull 1 1 . 42 2 . 14 2 . 60 flexibility 1 1 1 * 1 * droop 1 . 76 . 78 . 6 wt . 226 . 4 lb ./ sq . 262 . 2 lb ./ sq . 237 lb ./ sq . 237 lb ./ sq . it should be understood that the above examples are illustrative , and that compositions other than those described above can be used while utilizing the principles underlying the present invention . for example , other sources of fiber as well as mixtures of binders and / or crosslinking agents may be used in formulating the backing material . moreover , the backing material may be applied to various types of roofing products .