Nippon Paper Industries Co., Ltd.

Jujo Thermal Oy

Hiroshi Koyamoto

Masashi Okamoto

Takashi Ochi

Yuri Oishi

Hirokazu Morii

Masatsugu Kato

Koji Okomori

Kenta Watanabe

Masaaki Fukunaga

Satoshi Tsuda

Akio Miyajima

Masahito Suzuki

Akinobu Chatani

Hitoshi Nagao

A method for manufacturing a paper barrier base material includes a step of applying a water vapor barrier layer coating liquid that contains at least a water vapor barrier resin and a pigment onto a paper base material by a curtain coating method to form a water vapor barrier layer. The water vapor barrier layer coating liquid has a spinnability of 0.07 seconds or more and 0.4 seconds or less at a solid content concentration of 32% by weight and a temperature of 25° C. The method is intended to achieve good stability of a coating liquid and good continuous operability.

Method for manufacturing paper barrier base material

An object is to provide a paper barrier material resistant to fractures due to water vapor expansion when heated. As a solution, a paper barrier material is provided, which is characterized in that it comprises a gas barrier layer, a seal layer, a paper base material, and a pigment coating layer, being stacked in this order, wherein the laminate consisting only of the paper base material and pigment coating layer has an air permeation resistance of 2,500 seconds or lower as measured based on JAPAN TAPPI No. 5-2: 2000.

Paper barrier material

A method for manufacturing a paper barrier base material includes a step of applying a water vapor barrier layer coating liquid that contains at least a water vapor barrier resin and a pigment onto a paper base material by a curtain coating method to form a water vapor barrier layer, and a step of applying a gas barrier layer coating liquid that contains at least one polymer selected from water-soluble polymers and water-dispersible polymers onto the water vapor barrier layer by a curtain coating method without a drying step interposed between the two steps to form a gas barrier layer. The gas barrier layer coating liquid has a B-type viscosity equal to or higher than a B-type viscosity of the water vapor barrier layer coating liquid. The method is intended to suppress the occurrence of coating unevenness in wet-on-wet coating by a curtain coating method.

An object is to provide a paper barrier material having excellent gas barrier property as well as excellent water vapor barrier property, wherein such paper barrier material is suitable for packaging applications such as food packaging materials, containers, and cups. The means for achieving the object is to provide a paper barrier material characterized in that it meets the conditions in (1) to (3) below: (1) the water vapor permeability at 40&#xb1;0.5&#xb0; C. in temperature and 90&#xb1;2% in relative humidity is 3 g/m&#xb7;day or below; (2) the oxygen permeability at 23&#xb0; C. in temperature and 0% in relative humidity is 3 ml/m&#xb7;day&#xb7;atm or below; and (3) the oxygen permeability at 23&#xb0; C. in temperature and 85% in relative humidity is 3 ml/m&#xb7;day&#xb7;atm or below.

The present invention aims to provide coated papers for newsprint inks having fast ink drying properties comparable to those of conventional newsprint papers, without stickiness, and having good reproduction and sharpness of printed images comparable to those of coated papers printed using penetration drying type inks; as well as processes for preparing them. The invention provides for a coated printing paper for newsprint inks comprising a coating layer containing a pigment and an adhesive on a base paper, characterized in that the coating layer on the base paper has a coat weight of 4.0 g/mor more per side and that the coated paper has an oil absorbency under pressure of 20 g/mor more and a Bekk smoothness of 75 seconds or less; as well as a process for preparing the paper.

Coated papers for newsprint inks and processes for preparing them

The present invention aims to provide coated printing papers having fast ink drying properties comparable to those of conventional newsprint, without stickiness, having good printability such as sharpness of printed images comparable to those of coated papers, as well as having the effect of decomposing harmful substances by exposure to light, especially when using penetration drying type news inks. A coated printing paper is provided, comprising a coating layer containing a pigment and an adhesive on a base paper, characterized in that a fine titanium oxide powder having a photocatalytic effect is contained in the coating layer and that the coated paper has an oil absorbency of 20 g/mor more under pressure and a Bekk smoothness of 75 seconds or less.

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Tokyo, Japan

Hiroshi Koyamoto