A method is provided to crimp a sheet having, before crimping, a thickness, a moisture, a composition, and a width, the method including: obtaining one pre-crimping sheet characteristic among the thickness of the sheet, the moisture of the sheet, the composition of the sheet, and the width of the sheet; crimping the sheet to form a plurality of corrugations on the sheet, the crimping including providing a pair of crimping rollers defining a nip therebetween, the nip having a nip size, and inserting the sheet in the nip; evaluating a post-crimping characteristic of the sheet after crimping; and varying the nip size on the basis of the obtained one of the pre-crimping sheet characteristic, and on the basis of the evaluated post-crimping sheet characteristic. An apparatus to crimp a sheet is also provided.

A method is provided to crimp a sheet having, before crimping, a thickness, a moisture, a composition, and a width, the method including: obtaining one pre-crimping sheet characteristic among the thickness of the sheet, the moisture of the sheet, the composition of the sheet, and the width of the sheet; crimping the sheet to form a plurality of corrugations on the sheet, the crimping including providing a pair of crimping rollers defining a nip therebetween, the nip having a nip size, and inserting the sheet in the nip; evaluating a post-crimping characteristic of the sheet after crimping; and varying the nip size on the basis of the obtained one of the pre-crimping sheet characteristic, and on the basis of the evaluated post-crimping sheet characteristic. An apparatus to crimp a sheet is also provided.

Methods and apparatuses for applying coatings on a baggy web are provided. A Mayer rod and a back-up roll engage with each other to form a nip. The back-up roll has a deformable inner layer with a surface thereof covered by a deformable outer layer. The Mayer rod and the flexible web at a contacting area are impressed into the back-up roll with a machine-direction nip width W and a nip engagement depth D, which enables formation of a coating having a substantially uniform thickness.

Methods and apparatuses for applying coatings on a baggy web are provided. A Mayer rod and a back-up roll engage with each other to form a nip. The back-up roll has a deformable inner layer with a surface thereof covered by a deformable outer layer. The Mayer rod and the flexible web at a contacting area are impressed into the back-up roll with a machine-direction nip width W and a nip engagement depth D, which enables formation of a coating having a substantially uniform thickness.

An apparatus for producing a web of fibrous material includes a roll having incisions with a depth of 0.01-2.00 mm, a width of 0.01-2.00 mm, and a pitch 0.01-10.00 mm, and rotated at a peripheral velocity v.sub.1 equal to the velocity of an upstream apparatus unit; a belt stretched between transmission rollers that advances at a velocity v.sub.2 less than v.sub.1, wherein v.sub.1/v.sub.2 lies between 1.05 and 1.40; a presser roller rotating at a peripheral velocity v.sub.2, associated with a presser system acting to press the belt against the metal roll with a pressure of 1-200 kg per centimeter; and a system that feeds a sheet of pliable fibrous material between the belt and the roll, the belt having a longitudinal elongation of no more than 5%, dimensional stability along its entire length, a thickness of 1-10 cm, and a hardness 24-70° Shore A.

The present invention relates to a method for manufacturing a multilayer machine glazed paper comprising highly refined cellulose fibers, the method comprising the steps of: forming a first wet web by applying at least one first pulp suspension comprising highly refined cellulose fibers on a first wire; partially dewatering the first wet web to obtain a first partially dewatered web; forming a second wet web by applying at least one second pulp suspension comprising highly refined cellulose fibers on a second wire; partially dewatering the second wet web to obtain a second partially dewatered web; joining the first and second partially dewatered web to obtain a multilayer web; optional dewatering the multilayer web in a dewatering unit, and glazing the multilayer web in at least one glazing unit to obtain a multilayer machine glazed paper comprising highly refined cellulose fibers. The invention also relates to a multiply MG paper produced according to the method.

The present invention relates to a method for manufacturing a multilayer machine glazed paper comprising highly refined cellulose fibers, the method comprising the steps of: forming a first wet web by applying at least one first pulp suspension comprising highly refined cellulose fibers on a first wire; partially dewatering the first wet web to obtain a first partially dewatered web; forming a second wet web by applying at least one second pulp suspension comprising highly refined cellulose fibers on a second wire; partially dewatering the second wet web to obtain a second partially dewatered web; joining the first and second partially dewatered web to obtain a multilayer web; optional dewatering the multilayer web in a dewatering unit, and glazing the multilayer web in at least one glazing unit to obtain a multilayer machine glazed paper comprising highly refined cellulose fibers. The invention also relates to a multiply MG paper produced according to the method.

An apparatus for producing a web of fibrous material includes a roll having incisions with a depth of 0.01-2.00 mm, a width of 0.01-2.00 mm, and a pitch 0.01-10.00 mm, and rotated at a peripheral velocity v.sub.1 equal to the velocity of an upstream apparatus unit; a belt stretched between transmission rollers that advances at a velocity v.sub.2 less than v.sub.1, wherein v.sub.1/v.sub.2 lies between 1.05 and 1.40; a presser roller rotating at a peripheral velocity v.sub.2, associated with a presser system acting to press the belt against the metal roll with a pressure of 1-200 kg per centimeter; and a system that feeds a sheet of pliable fibrous material between the belt and the roll, the belt having a longitudinal elongation of no more than 5%, dimensional stability along its entire length, a thickness of 1-10 cm, and a hardness 24-70 Shore A.

Methods and apparatuses for applying coatings on a baggy web are provided. A Mayer rod and a back-up roll engage with each other to form a nip. The back-up roll has a deformable inner layer with a surface thereof covered by a deformable outer layer. The Mayer rod and the flexible web at a contacting area are impressed into the back-up roll with a machine-direction nip width W and a nip engagement depth D, which enables formation of a coating having a substantially uniform thickness.

An apparatus for producing a web of fibrous material includes a roll having incisions with a depth of 0.01-2.00 mm, a width of 0.01-2.00 mm, and a pitch 0.01-10.00 mm, and rotated at a peripheral velocity v.sub.1 equal to the velocity of an upstream apparatus unit; a belt stretched between transmission rollers that advances at a velocity v.sub.2 less than v.sub.1, wherein v.sub.1/v.sub.2 lies between 1.05 and 1.40; a presser roller rotating at a peripheral velocity v.sub.2, associated with a presser system acting to press the belt against the metal roll with a pressure of 1-200 kg per centimeter; and a system that feeds a sheet of pliable fibrous material between the belt and the roll, the belt having a longitudinal elongation of no more than 5%, dimensional stability along its entire length, a thickness of 1-10 cm, and a hardness 24-70 Shore.