The present invention relates to a stabilized calcium carbonate filler, a process for stabilizing calcium carbonate, the use of the stabilized filler in a paper making system, and an improved paper making process wherein calcium carbonate is used as a filler. Specifically, the invention relates to a
The present invention relates to a stabilized calcium carbonate filler, a process for stabilizing calcium carbonate, the use of the stabilized filler in a paper making system, and an improved paper making process wherein calcium carbonate is used as a filler. Specifically, the invention relates to a process wherein the rate of dissolution of calcium carbonate filler is retarded as compared to the rate found in conventional paper making processes. The rate of dissolution is retarded by addition of carbon dioxide to a slurry containing the calcium carbonate filler.
대표청구항▼
The present invention relates to a stabilized calcium carbonate filler, a process for stabilizing calcium carbonate, the use of the stabilized filler in a paper making system, and an improved paper making process wherein calcium carbonate is used as a filler. Specifically, the invention relates to a
The present invention relates to a stabilized calcium carbonate filler, a process for stabilizing calcium carbonate, the use of the stabilized filler in a paper making system, and an improved paper making process wherein calcium carbonate is used as a filler. Specifically, the invention relates to a process wherein the rate of dissolution of calcium carbonate filler is retarded as compared to the rate found in conventional paper making processes. The rate of dissolution is retarded by addition of carbon dioxide to a slurry containing the calcium carbonate filler. of claim 7, wherein the second double-felted press is arranged such that the upper press felt thereof picks the multilayer web up from the lower press felt of the first double-felted press. 11. The board machine of claim 8, wherein each double-felted press comprises a roll press in which the upper press member comprises a press roll. 12. A method for manufacturing a multilayer cardboard web with a printable surface, comprising: forming a first board layer in a first forming unit such that the first board layer has said printable surface; forming at least one additional board layer in at least one additional forming unit; couching the first board layer and said at least one additional board layer together to form a multilayer cardboard web having said printable surface; transferring the multilayer cardboard web onto a lower press felt of a first double-felted press with said printable surface in contact with a surface of the lower press felt, wherein the first double-felted press comprises an upper press member disposed within a loop formed by an upper press felt and a lower press member disposed within a loop formed by the lower press felt; and passing the multilayer cardboard web through a nip of the first double-felted press sandwiched between the lower press felt and the upper press felt; wherein the surface of the lower press felt in contact with the printable surface of the multilayer cardboard web is smoother than a web-contacting surface of the upper press felt in contact with an opposite surface of the web so as to cause the web to remain adhered to the lower press felt as the press felts diverge downstream of the nip. 13. The method of claim 12, wherein the upper press member includes a shoe and the lower press member comprises a press roll, the shoe defining a surface that forms an extended nip with the press roll, and wherein at a discharge side of the nip the lower press felt remains in contact with the press roll for a sector angle α of at least 10° beyond a 0 point at which the surface of the shoe transitions from a concave to a convex curvature. 14. The method of claim 13, wherein the upper press felt departs the nip at an angle β relative to a 0 line that is tangent to the shoe at said 0 point, the angle β being about -5° to +5°. 15. The method of claim 12, wherein the upper press member comprises a press roll having an outer surface that is tangent to the lower press member at a 0 point, and at a discharge side of the nip the lower press felt remains in contact with the lower press roll for a sector angle α of at least 10° beyond the 0 point. 16. The method of claim 15, wherein the upper press felt departs the nip at an angle β relative to a 0 line that is tangent to the lower press roll at said 0 point, the angle β being about -5° to +10°. 17. The method of claim 12, wherein the multilayer cardboard web is dewatered by passing the web through the first double-felted press and then through a second double-felted press, the upper press felt of each press receiving the web upstream of the nip. 18. The method of claim 17, wherein the upper press felt of the first double-felted press picks the multilayer cardboard web up from an extended forming wire of the first forming unit, and the upper press felt of the second double-felted press picks the web up from the lower press felt of the first double-felted press after the web has passed through the first double-felted press.
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이 특허에 인용된 특허 (5)
Passaretti June D. (Liberty Corner NJ), Acid-stabilized calcium carbonate, process for its production and method for its use in the manufacture of acidic paper.
Passaretti June D. (Liberty Corner NJ), Acid-stabilized calcium carbonate, process for its production and method for its use in the manufacture of acidic paper.
Andersson Kjell R. (DomsjSEX) stensson Per O. L. (DomsjSEX) Kuni Stefan O. (Kotka FIX), Paper manufacturing process, and papers obtainable by means of that process.
Skrzypczak, Mathieu; Maurer, Marc; Schmölzer, Thomas, Process for the production of precipitated calcium carbonate, precipitated calcium carbonate and uses thereof.
Skrzypczak, Mathieu; Maurer, Marc; Schmölzer, Thomas, Process for the production of precipitated calcium carbonate, precipitated calcium carbonate and uses thereof.
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