There is provided a high-density paper having a grammage measured according to ISO 536:2012 of 30-75 g/m.sup.2 and a density measured according to ISO 534:2011 above 1000 kg/m.sup.3 and wherein the high-density paper is impregnated on each side with 0.3-4.0 g/m.sup.2, such as 0.5-3.0 g/m.sup.2, of a polymer selected from the group consisting of polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), carboxymethylated cellulose (CMC), nanocrystalline cellulose (NCC) and carboxy methyl starch (CMS).

An object of the present invention is to provide a carbon sheet to be used suitably for a gas diffusion electrode, in which the carbon sheet does not worsen the electrical resistance in the through-plane direction, and can be prevented from the deflection into the gas flow channels provided in the bipolar plate, although such characteristics. A carbon sheet according to the present invention, provided to achieve the above-described object, is a carbon sheet including a first surface and a second surface located at the opposite side to the first surface; wherein, assuming that a specific section is equally divided into 20 portions in the thickness direction to form 20 layers, the degree of fiber orientation of the first surface side outermost layer of the 20 layers is 1.20 or more and 3.00 or less; and wherein, assuming that a region composed of consecutive layers that are included in the 20 layers, and satisfy specific conditions is a first surface side region, and that a region composed of a layer(s) included in the 20 layers but not included in the first surface side region is a second surface side region, the thickness of the first surface side region is 40% or less of the thickness of the whole carbon sheet, and a difference between the average degree of fiber orientation of the second surface side region and the degree of fiber orientation of the first surface side outermost layer is larger than 0.10.

An object of the present invention is to provide a carbon sheet to be used suitably for a gas diffusion electrode, in which the carbon sheet does not worsen the electrical resistance in the through-plane direction, and can be prevented from the deflection into the gas flow channels provided in the bipolar plate, although such characteristics. A carbon sheet according to the present invention, provided to achieve the above-described object, is a carbon sheet including a first surface and a second surface located at the opposite side to the first surface; wherein, assuming that a specific section is equally divided into 20 portions in the thickness direction to form 20 layers, the degree of fiber orientation of the first surface side outermost layer of the 20 layers is 1.20 or more and 3.00 or less; and wherein, assuming that a region composed of consecutive layers that are included in the 20 layers, and satisfy specific conditions is a first surface side region, and that a region composed of a layer(s) included in the 20 layers but not included in the first surface side region is a second surface side region, the thickness of the first surface side region is 40% or less of the thickness of the whole carbon sheet, and a difference between the average degree of fiber orientation of the second surface side region and the degree of fiber orientation of the first surface side outermost layer is larger than 0.10.

An aqueous paper barrier coating and methods for improving barrier properties of packaging material are described. The packaging material includes a substrate with coatings to provide a packaging material having tailored moisture vapor transmission, oxygen permeation or transmission, oil and grease resistance, and light properties.

An aqueous paper barrier coating and methods for improving barrier properties of packaging material are described. The packaging material includes a substrate with coatings to provide a packaging material having tailored moisture vapor transmission, oxygen permeation or transmission, oil and grease resistance, and light properties.

The present invention provides water-based coatings that provide liquid resistance when applied to various substrates. The coatings are particularly suitable for cellulosic substrates such as paper or paper board. In addition to liquid resistance, the coatings have good heat sealability, and are resistant to roll blocking. Preferably, the coatings are recyclable and/or repulpable with the substrates to which they are applied. The coating compositions comprise one or more polymer binders, and one or more particles. Preferably, at least one polymer binder has a glass transition temperature (Tg) less than 10? C. Preferably, at least one polymer binder has a heat seal onset temperature of less than 200? C. Preferably, at least one particle has a mean particle size greater than 4 ?m. It is also preferable that the particles have a melting point greater than 60? C.

The present invention provides water-based coatings that provide liquid resistance when applied to various substrates. The coatings are particularly suitable for cellulosic substrates such as paper or paper board. In addition to liquid resistance, the coatings have good heat sealability, and are resistant to roll blocking. Preferably, the coatings are recyclable and/or repulpable with the substrates to which they are applied. The coating compositions comprise one or more polymer binders, and one or more particles. Preferably, at least one polymer binder has a glass transition temperature (Tg) less than 10? C. Preferably, at least one polymer binder has a heat seal onset temperature of less than 200? C. Preferably, at least one particle has a mean particle size greater than 4 ?m. It is also preferable that the particles have a melting point greater than 60? C.

A coated paperboard including a paperboard substrate having a first side and a second side, and a multilayer coating having two or more layers in contact with the first side of the paperboard substrate, the multilayer coating including a base coating in contact with the paperboard substrate, the base coating having a coat weight from 6 to 10 pounds per 3000 ft.sup.2, and a top coating forming the outermost layer of the multilayer coating, the top coating having a coat weight from 3 to 10 pounds per 3000 ft.sup.2, wherein the multilayer coating comprises binder and pigment, the binder comprising one or more synthetic polymer binders and one or more natural biodegradable binders, and wherein the coated paperboard has a caliper of at least 0.010.

A coated paperboard including a paperboard substrate having a first side and a second side, and a multilayer coating having two or more layers in contact with the first side of the paperboard substrate, the multilayer coating including a base coating in contact with the paperboard substrate, the base coating having a coat weight from 6 to 10 pounds per 3000 ft.sup.2, and a top coating forming the outermost layer of the multilayer coating, the top coating having a coat weight from 3 to 10 pounds per 3000 ft.sup.2, wherein the multilayer coating comprises binder and pigment, the binder comprising one or more synthetic polymer binders and one or more natural biodegradable binders, and wherein the coated paperboard has a caliper of at least 0.010.

A method of imparting hydrophobic properties to a paper product that comprises providing a paper product; immersing said paper product into a metal ion solution; and drying the paper product.