International Paper Company

Alexander A Koukoulas

Kosaraju Krishna Mohan

Peter Matthew Froass

David Verd Reed

Zheng Tan

Gopal Goyal

Michael J Smith

K Krishna Mohan

Thomas Z Fu

Dennis W Anderson

Kapil Mohan Singh

Thomas E Amidon

William L Brown

Fernand Mora

M C Matthew

Timothy S Sammarco

Douglas L Hamilton

Thomas E Altman

Phillip Norrdahl

A method of producing a modified pulp for use in paper or paper web products, the method comprising treating wood chips in an extraction process to remove hemicellose to form treated wood chips; and subjecting said treated wood chips to chemical or semichemical pulping to form a modified Kraft pulp wherein the amount of hemicellulose contained in the modified Kraft pulp is from about 5 to about 10% by dry weight of the modified pulp.

Modified kraft fibers

A method of producing a modified pulp comprising treating wood chips in an extraction process to remove hemicellose to form treated wood chips; and subjecting said treated wood chips to chemical or semichemical pulping to form a modified Kraft pulp wherein the amount of hemicellulose contained in the modified Kraft pulp is from about 5 to about 10% by dry weight of the modified pulp.

Modified Kraft fibers

The invention provides a low density paperboard material and associated method for use in producing an insulated container, and is especially well-suited for making cups. The paperboard material comprises a paperboard web including wood fibers and expanded microspheres, and has a relatively low density ranging from about 6 to about 10 lb/3 MSF/mil, a relatively high caliper ranging from about 24 to about 35 mil, and an internal bond strength of at least about 80&#xd7;10ft-lbf., preferably at least 100&#xd7;10lft-lbf. For applications such as cups the material is also coated on one or both sides with a barrier coating, preferably low density polyethylene, to limit liquid penetration into the web. The low density paperboard material of the invention is convertible for manufacture of containers, particularly cups, and exhibits insulative properties comparable to higher cost materials conventionally used to make cups. Also, the surface of the low density board may have a Sheffield smoothness of 300 SU or greater compared with the surface smoothness of 160 to 200 SU for conventional cupstock, the latter having been thought necessary for adequate print quality. However, it has been found that the low density board exhibits good printability on flexo printing machines despite its relatively rough surface, which is surprising and bonus effect realized along with the insulative and other properties of the board.

Low density paperboard articles

The invention provides a low density paperboard material and associated method for use in producing an insulated container, and is especially well-suited for making cups. The paperboard material comprises a paperboard web including wood fibers and expanded microspheres, and has a relatively low density ranging from about 6 to about 10 lb/3MSF/mil, a relatively high caliper ranging from about 24 to about 35 mil, and an internal bond strength of at least about 80&#xd7;10ft-lbf., preferably at least 100&#xd7;10lft-lbf. For applications such as cups the material is also coated on one or both sides with a barrier coating, preferably low density polyethylene, to limit liquid penetration into the web. The low density paperboard material of the invention is convertible for manufacture of containers, particularly cups, and exhibits insulative properties comparable to higher cost materials conventionally used to make cups. Also, the surface of the low density board may have a Sheffield smoothness of 300 SU or greater compared with the surface smoothness of 160 to 200 SU for conventional cupstock, the latter having been thought necessary for adequate print quality. However, it has been found that the low density board exhibits good printability on flexo printing machines despite its relatively rough surface, which is surprising and bonus effect realized along with the insulative and other properties of the board.

The invention provides a low density paperboard material for use in producing an insulated container, and is especially well-suited for making cups. The paperboard material comprises a paperboard web including wood fibers and expanded microspheres, and has a relatively low density ranging from about 6 to about 10 lb/3MSF/mil, a relatively high caliper ranging from about 24 to about 35 mil, and an internal bond strength of at least about 80&#xd7;10ft-lbpreferably at least 100&#xd7;10ft-lb. For applications such as cups the material is also coated on one or both sides with a barrier coating, preferably low density polyethylene, to limit liquid penetration into the web. The low density paperboard material of the invention is convertible for manufacture of containers, particularly cups, and the surface of the low density board may have a Sheffield smoothness of 300 SU or greater.

The invention provides a low density paperboard material and associated method for use in producing an insulated container, and is especially well-suited for making cups. The paperboard material comprises a paperboard web including wood fibers and expanded microspheres, and has a relatively low density ranging from about 6 to about 10 lb/3MSF/mil, a relatively high caliper ranging from about 24 to about 35 mil, and an internal bond strength of at least about 80&times;10 ft-lbf., preferably at least 100&times;10 lft-lbf. For applications such as cups the material is also coated on one or both sides with a barrier coating, preferably low density polyethylene, to limit liquid penetration into the web. The low density paperboard material of the invention is convertible for manufacture of containers, particularly cups, and exhibits insulative properties comparable to higher cost materials conventionally used to make cups. Also, the surface of the low density board may have a Sheffield smoothness of 300 SU or greater compared with the surface smoothness of 160 to 200 SU for conventional cupstock, the latter having been thought necessary for adequate print quality. However, it has been found that the low density board exhibits good printability on flexo printing machines despite its relatively rough surface, which is surprising and bonus effect realized along with the insulative and other properties of the board.

Low density paper and paperboard articles

The invention relates to a laminated board grade structure used for low cost, enhanced graphics packaging. The product contains an unbleached or bleached substrate board and a lightweight coated unprinted white paper grade laminated to the unbleached board substrate to produce a product with a smooth coated, glossy surface for quality graphics printing.

Laminated board for enhanced graphics packaging and strength

A method for manufacture of loaded paper or paperboard products, comprising the steps of separating at least one process stream from the papermaking process, wherein the process stream includes fines and/or filler; combining the process stream with long fibers and thickening to form a residue; treating the residue to form fiber-filler complexes; and using the fiber-filler complexes in the papermaking process to form the paper.

Method to manufacture paper using fiber filler complexes

A paperboard product having at least one layer of bleached or semi-bleached pulp and having improved smoothness and reduced bulk loss. For paperboard having sizing without pigment, the smoothness on the printed side, measured by the Parker test is better (lower) than 6.5 when measured using a pressure of 10 kgf/cm while the smoothness measured by the Hagerty/Sheffield test is not below 280 Sheffield units. For paperboard having sizing with pigment, the Parker smoothness is less than 5.0 and the Hagerty/Sheffield smoothness is not less than 180 Sheffield units. The web is finished by applying temperature and moisture gradients, then smoothing the web surface using extended nip calendering. The surface temperature of the calendering roll is maintained at 250-400&deg; F. Prior to entering the extended nip, the web surface is moisturized using steam showers. The nipload applied in the heated extended nip is preferably between 300 to 2,500 pli.

Paperboard of improved smoothness and bulk

A paper product suitable for use in making envelopes and the like and having enhanced printability. The enhancement in printability is attained through the use of shoe nip calendering. The final product has the following material properties: (1) a basis weight in the range 16-32 lb./1,300 ft,; (2) a density equal to or less than 0.75 g/cc; (3) a smoothness as measured by the Hagerty/Sheffield test (TAPPI Test Method T 538 om-88) greater than 200 Sheffield units; and (4) a Parker Print Surf roughness as measured by the Parker test (TAPPI Test Method T 555 om-94) less than 5.0 microns (measured using a pressure of 10 kgf/cm,with a soft backing).

Paper product having enhanced printing properties and related method of manufacture

A paperboard product having at least one layer of bleached or semi-bleached pulp and having improved smoothness and reduced bulk loss. For paperboard having sizing without pigment, the smoothness on the printed side as measured by the Parker test is better (lower) than 6.5 when measured using a pressure of 10 kgf/cm,while the smoothness measured by the Hagerty/Sheffield test is not below 280 Sheffield units. For paperboard having sizing with pigment, the Parker smoothness is less than 5.0 and the Hagerty/Sheffield smoothness is not less than 180 Sheffield units. The web is finished by applying temperature and moisture gradients to the web and then smoothing the web surface using extended nip calendering. The surface of the calendering roll is maintained at a temperature of 250-400&deg; F. Prior to entering the extended nip, the web surface is moisturized using steam showers. The nipload applied in the heated extended nip is preferably in the range of 300 to 2,500 pli.

Method for finishing paperboard to achieve improved smoothness

A multilayer linerboard product having a top layer made up of bleached/unbleached virgin or recycled pulp and at least one bottom layer made up of unbleached pulp. The external surface of the top layer has reduced gloss mottle and improved printing properties. In particular, the top surface of the multilayer linerboard has a Parker smoothness less than 6.5 and a Hagerty/Sheffield smoothness in the range of 240 to 280. Print voids on a flexo printed product are less than 0.20% (by area) as measured by image analysis. These improvements are achieved in an extended nip calender section having a heated calender roll, a backing roll or shoe and a conformable belt. Preferably, the nip width is 1 to 25 cm. The temperature of the surface of the heated calender roll is preferably maintained in the range of 300 to 500&deg; F. The nipload between the heated calender roll and the conformable belt is preferably maintained in the range of 500 to 2,500 pli.

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Ridgewood, NJ, United States of America

Alexander A Koukoulas