Dimensionally stable cellulosic backing web

A wet web impregnation method of manufacturing an asbestos-free backing web having a thickness from about 0.010 inch to about 0.120 inch, said web having fibrous portion and fibrous portion additives present from about 50% to about 88% of dry weight of backing web and having binder portion and binder portion additives present from about 50% to about 12% of dry weight of backing web, said fibrous portion and fibrous portion additives including cellulosic fiber in an amount from about 40% to about 85%, glass fiber in an amount from about 3% to about 35%, polyolefin fiber having a melting point in the range of about 230.degree. F. to about 380.degree. F. in an amount from about 10% to about 56%, and antifungal-antimildew agent in an amount from about 0.5% to about 2.0% all with respect to the dry weight of said fibrous portion and fibrous portion additives, said binder portion and binder portion additives including a synthetic rubber latex or combination of latices, said web having dimensional stability in the machine direction, the cross machine direction and the diagonal direction such that the web in these directions varies in dimension by not more than about 0.5% when subjected to relative humidity changes in the range of relative humidity of 0% to 100%, or when subjected to water soaking with respect to the complete range of relative humidity, said web also exhibiting no visible fungal growth after a 28 day incubation period at 83.degree.-86.degree. F. and not less than 85% relative humidity, the web having been placed at the start of said period on the surface of nutrient-salt agar and inoculated with a mixed spore suspension of Asperigillus niger, Penicillium funiculosum, Chaetomium globosum, Trichloderma sp, and Pullularia pullulans, and comprising the steps of pumping with a fan pump a slurry of said fibrous portion and fibrous portion additives to a sheet former forming a web, pressing in a press section said web, which is then saturated in a saturator with said binder portion and binder portion additives, dried by dryers, compacted on a plurality of steel rolls, and wound on a windup reel, and wherein all components of said fibrous portion and fibrous portion additives except said glass fiber are dispersed in water in a pulper, stirred in a drop chest, macerated in a refiner, and retained in a machine chest, wherein the improvement comprises furnishing a portion of the output of said machine chest to a glass fiber dispersion tank partially filled with water at ambient temperature, and furnishing the remainder of said machine chest output to said fan pump, filling said glass fiber dispersion tank with water at ambient temperature, introducing said glass fiber in portions with stirring to said glass fiber dispersion tank to form a glass fiber dispersion, pumping said glass fiber dispersion to a dispersion holding tank, pumping said glass fiber dispersion from said dispersion holding tank to a dispersion feed tank, and pumping said glass fiber dispersion from said dispersion feed tank to said fan pump, where mixing with the output of said machine chest forms said fibrous portion and fibrous portion additives slurry.

A dry web impregnation method of manufacturing an asbestos-free backing web having a thickness from about 0.006 to about 0.060 inch, said web having fibrous portion and fibrous portion additives present from about 50% to about 88% of dry weight of backing web and having binder portion and binder portion additives present from about 50% to about 12% of dry weight of backing web, said fibrous portion and fibrous portion additives including cellulosic fiber in an amount from about 40% to about 85%, glass fiber in an amount from about 3% to about 35%, polyolefin fiber having a melting point in the range of about 230.degree. F. to about 380.degree. F. in an amount from about 10% to about 56%, and antifungal-antimildew agent in an amount from about 0.5% to about 2.0% all with respect to the dry weight of said fibrous portion and fibrous portion additives, said binder portion and binder portion additives including a synthetic rubber latex or combination of latices, said web having dimensional stability in the machine direction, the cross machine direction and the diagonal direction such that the web in these directions varies in dimension by not more than about 0.5% when subjected to relative humidity changes in the range of relative humidity of 0% to 100%, or when subjected to water soaking with respect to the complete range of relative humidity, said web also exhibiting no visible fungal growth after a 28 day incubation period at 83.degree.-86.degree. F. and not less than 85% relative humidity, the web having been placed at the start of said period on the surface of nutrient-salt agar and inoculated with a mixed spore suspension of Aspergillus niger, Penicillium funiculosum, Chaetomium globosum, Trichloderma sp, and Pullularlia pullulans, and comprising the steps of pumping with a fan pump a slurry of said fibrous portion and fibrous portion additives to a sheet former forming a web, pressing in a press section said web, which is then dried by dryers, compacted on a plurality of steel rolls, wound on a windup reel, built on a core by a rewinder, unwound on an unwind reel, saturated with a saturant of said binder portion and binder portion additives in a saturator, pressed by squeeze rolls, dried by dryers, the product from said dryers passing to a calender stack and then to a windup reel on which the product is wound, and wherein all components of said fibrous portion and fibrous portion additives except said glass fiber are pulped in water in a pulper, stirred in a drop chest, macerated in a refiner, and retained in a machine chest, wherein the improvement comprises furnishing a portion of the output of said machine chest to a glass fiber dispersion tank partially filled with water at ambient temperature, and furnishing the remainder of said machine chest output to said fan pump, filling said glass fiber dfispersion tank with water at ambient temperature, introducing said glass fiber in portions with stirring to said glass fiber dispersion tank to form a glass fiber dispersion, pumping said glass fiber dispersion to a dispersion holding tank, pumping said glass fiber dispersion from said dispersion holding tank to a dispersion feed tank, and pumping said glass fiber dispersion from said dispersion feed tank to said fan pump, where mixing with the output of said machine chest forms said fibrous portion and fibrous portion additives slurry.

A latex beater deposition method of manufacturing an asbestos-free backing web having a thickness from about 0.003 inch to about 0.150 inch, said web having fibrous portion and fibrous portion additives present from about 50% to about 88% of dry weight of backing web and having binder portion and binder portion additives present from about 50% to about 12% of dry weight of backing web, said fibrous portion and fibrous portion additives including cellulosic fiber in an amount from about 40% to about 85%, glass fiber in an amount from about 3% to about 35%, polyolefin fiber having a melting point in the range of about 230.degree. F. to about 380.degree. F. in an amount from about 10% to about 56%, and antifungal-antimildew agent in an amount from about 0.5% to about 2.0% all with respect to the dry weight of said fibrous portion and fibrous portion additives, said binder portion and binder portion additives including a synthetic rubber latex or combination of latices, said web having dimensional stability in the machine direction, the cross machine direction and the diagonal direction such that the web in these directions varies in dimension by not more than about 0.5% when subjected to relative humidity changes in the range of relative humidity of 0% to 100%, or when subjected to water soaking with respect to the complete range of relative humidity, said web also exhibiting no visible fungal growth after a 28 day incubation period at 83.degree.-86.degree. F. and not less than 85% relative humidity, the web having been placed at the start of said period on the surface of nutrient-salt agar and inoculated with a mixed spore suspension of Aspergillus niger, Penicillium funiculosum, Chaetomium globosum, Trichoderma sp, and Pullularia pullulans, and comprising the steps of pumping with a fan pump a slurry of said fibrous portion and fibrous portion additives, upon which said binder portion and binder portion additives have been deposited, to a sheet former forming a web, pressing in a press section said web, which is then dried by dryers, compacted on a plurality of steel rolls, and wound on a windup reel, and wherein all components of said fibrous portion and fibrous portion additives except said glass fiber are pulped in a pulper with water, stirred in a drop chest, and macerated in a refiner to form a refined fibrous slurry, the improvement comprising introducing a portion of said refined fibrous slurry into a glass fiber dispersion tank partially filled with water at ambient temperature, transferring the remaining portion of said refined fibrous slurry in said refiner to a latex deposition chest having means for combining said refined fibrous slurry with said binder portion and binder portion additives, the output of said latex deposition chest being transferred to a machine chest for stirring and further transfer to said fan pump, filling said glass fiber dispersion tank with water at ambient temperature, introducing said glass fiber in portions with stirring to said glass fiber dispersion tank to form a glass fiber dispersion, pumping said glass fiber dispersion to a dispersion holding tank, pumping said glass fiber dispersion from said dispersion holding tank to a dispersion feed tank, and pumping said glass fiber dispersion from said dispersion feed tank to said fan pump, where said glass fiber dispersion is mixed with the output of said machine chest.

A continuous latex wet-end deposition method of manufacturing as asbestos-free backing web having a thickness from about 0.003 inch to about 0.150 inch, said web having fibrous portion and fibrous portion additives present from about 50% to about 88% of dry weight of backing web and having binder portion and binder portion additives present from about 50% to about 12% of dry weight of backing web, said fibrous portion and fibrous portion additives including cellulosic fiber in an amount from about 40% to about 85%, glass fiber in an amount from about 3% to about 35%, polyolefin fiber having a melting point in the range of about 230.degree. F. to about 380.degree. F. in an amount from about 10% to about 56%, and antifungalantimildew agent in an amount from about 0.5% to about 2.0% all with respect to the dry weight of said fibrous portion and fibrous portion additives, said binder portion and binder portion additives including a synthetic rubber latex or combination of lactices, said web having dimensional stability in the machine direction, the cross machine direction and the diagonal direction such that the web in these directions varies in dimension by not more than about 0.5% when subjected to relative humidity changes in the range of relative humidity of 0% to 100%, or when subject to water soaking with respect to the complete range of relative humidity, said web also exhibiting no visible fungal growth after a 28 day incubation period at 83.degree.-86.degree. F. and not less than 85% relative humidity, the web having been placed at the start of said period on the surface of nutrient-salt agar and inoculated with a mixed spore suspension of Aspergillus niger, Penicillium funiculosum, Chaetomium globosum, Trichoderma sp, and Pullularia pullulans, wherein a slurry of said fibrous portion and fibrous portion additives is supplied by a fan pump to a sheet former, said binder portion and binder portion additives having been mixed with and uniformly deposited on said fibrous portion and fibrous portion additives at said fan pump, a web is formed by said sheet former, said web is pressed in a press section, dried by dryers, compacted by a calender stack, and wound on a windup reel, and wherein all components of said fibrous portion and fibrous portion additives except said glass fiber are pulped in a pulper with water, stirred in a drop chest, and macerated in a refiner to form a refined fibrous slurry, the improvement comprising introducing a portion of said refined fibrous slurry into a glass fiber dispersion tank partially filled with water at ambient temperature, furnishing the remainder of said refined fibrous slurry to a machine chest for stirring and further transfer to said fan pump, filling said glass fiber dispersion tank with water at ambient temperature, introducing said glass fiber in portions with stirring to said glass fiber dispersion tank to form a glass fiber dispersion, pumping said glass fiber dispersion to a dispersion holding tank, pumping said glass fiber dispersion from said dispersion holding tank to a dispersion feed tank, and pumping said glass fiber dispersion from said dispersion feed tank to said fan pump, where mixing with the output of said machine chest forms said fibrous portion and fibrous portion additives slurry.

A continuous latex wet-end deposition method of manufacturing an asbestos-free backing web having a thickness from about 0.003 inch to about 0.150 inch, said web having fibrous portion and fibrous portion additives present from about 50% to about 88% of dry weight of backing web and having binder portion and binder portion additives present from about 50% to about 12% of dry weight of backing web, said fibrous portion and fibrous portion additives including cellulosic fiber in an amount from about 40% to about 85%, glass fiber in an amount from about 3% to about 35%, polyolefin fiber having a melting point in the range of about 230.degree. F. to about 380.degree. F. in an amount from about 10% to about 56%, and antifungalantimildew agent in an amount from about 0.5% to about 2.0% all with respect to the dry weight of said fibrous portion and fibrous portion additives, said binder portion and binder portion additives including a synthetic rubber latex or combination of lactices, said web having dimensional stability in the machine direction, the cross machine direction and the diagonal direction such that the web in these directions varies in dimension by not more than about 0.5% when subjected to relative humidity changes in the range of relative humidity of 0% to 100%, or when subjected to water soaking with respect to the complete range of relative humidity, said web also exhibiting no visible fungal growth after a 28 day incubation period at 83.degree.-86.degree. F. and not less than 85% relative humidity, the web having been placed at the start of said period on the surface of nutrient-salt agar and inoculated with a mixed spore suspension of Aspergillus niger, Penicillium funiculosum, Chaetomium globosum, Trichoderma sp, and Pullularia pullulans, wherein a slurry of said fibrous portion and fibrous portion additives is supplied by a fan pump to a sheet former having a headbox, said binder portion and binder portion additives are introduced to said fibrous portion and fibrous portion additives slurry at said headbox, and wherein said binder portion and binder portion additives are uniformly deposited on said fibrous portion and fibrous portion additives, and a web is formed by said sheet former, said web is pressed in a press section, dried by dryers, compacted by a calender stack, and wound on a windup reel, and wherein all components of said fibrous portion and fibrous portion additives except said glass fiber are pulped in a pulper with water, stirred in a drop chest, and macerated in a refiner to form a refined fibrous slurry, wherein the improvement comprises introducing a portion of said refined fibrous slurry into a glass fiber dispersion tank partially filled with water at ambient temperature, furnishing the remainder of said refined fibrous slurry to a machine chest for stirring and further transfer to said fan pump, filling said glass fiber dispersion tank with water at ambient temperature, introducing said glass fiber in portions with stirring to said glass fiber dispersion tank to form a glass fiber dispersion, pumping said glass fiber dispersion to a dispersion holding tank, pumping said glass fiber dispersion from said dispersion holding tank to a dispersion feed tank, and pumping said glass fiber dispersion from said dispersion feed tank to said fan pump, where mixing with the output of said machine chest forms said fibrous portion and fibrous portion additives slurry.

A continuous latex wet-end deposition method of manufacturing an asbestos-free backing web, said web having fibrous portion and fibrous portion additives present from about 50% to about 88% of dry weight of backing web and having binder portion and binder portion additives present from about 50% to about 12% of dry weight of backing web, said fibrous portion and fibrous portion additives including cellulosic fiber in an amount from about 40% to about 85%, glass fiber in an amount from about 3% to about 35%, polyolefin fiber having a melting point in the range of about 230.degree. F. to about 380.degree. F. in an amount from about 10% to about 56%, and antifungalantimildew agent in an amount from about 0.5% to about 2.0% all with respect to the dry weight of said fibrous portion and fibrous portion additives, said binder portion and binder portion additives including a synthetic rubber latex or combination of latices, said web having dimensional stability in the machine direction, the cross machine direction and the diagonal direction such that the web in these directions varies in dimension by not more than about 0.5% when subjected to relative humidity changes in the range of relative humidity of 0% to 100%, or when subjecting to water soaking with respect to the complete range of relative humidity, said web also exhibiting no visible fungal growth after a 28 day incubation period at 83.degree.-86.degree. F. and not less than 85% relative humidity, the web having been placed at the start of said period on the surface of nutrient-salt agar and inoculated with a mixed spore suspension of Aspergillus niger, Penicillium funiculosm, Chaetomium globosum, Trichoderma sp, and Pullularia pullulans, wherein a slurry of said fibrous portion and fibrous portion additives is supplied by a fan pump to a sheet former, wherein said sheet former is a cylinder machine having a vat, with a pipe line feeding said fibrous portion and fibrous portion additives slurry from said fan pump to said vat, said binder portion and binder portion additives being introduced to said fibrous portion and fibrous portion additives slurry at said pipe line, and wherein said binder portion and binder portion additives are uniformly deposited on said fibrous portion and fibrous portion additives, and a web is formed by said sheet former, said web is pressed in a press section, dried by dryers, compacted by a calender stack, and wound on a windup reel, and wherein all components of said fibrous portion and fibrous portion additives except said glass fiber are pulped in a pulper with water, stirred in a drop chest, and macerated in a refiner to form a refined fibrous slurry, wherein the improvement comprises introducing a portion of said refined fibrous slurry into a glass fiber dispersion tank partially filled with water at ambient temperature, furnishing the remainder of said refined fibrous slurry to a machine chest for stirring and further transfer to said fan pump, filling said glass fiber dispersion tank with water at ambient temperature, introducing said glass fiber in portions with stirring to said glass fiber dispersion tank to form a glass fiber dispersion, pumping said glass fiber dispersion to a dispersion holding tank, pumping said glass fiber dispersion from said dispersion holding tank to a dispersion feed tank, and pumping said glass fiber dispersion from said dispersion feed tank to said fan pump, where mixing with the output of said machine chest forms said fibrous portion and fibrous portion additives slurry.