# US 7,407,700 B2 · Coated paper for printing

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- Number: US 7,407,700 B2
- Document ID: US7407700B2
- Status: Granted
- Kind: B2
- Application number: 10/553,789
- Filed: 2005-10-20
- Published: 2007-03-01
- Granted: 2008-08-05
- Earliest claimed: 2003-04-24
- Assignees: Oji Paper Co., Ltd.
- Inventors: Takayuki Kishida; Yoshiki Kojima; Nobuo Yamada; Yasuhiro Arai; Tetsuya Hirabayashi
- Web page: https://patentgrep.com/patent/US7407700B2

## CPC

- D21H 19/82: superposed {(D21H19/84 takes precedence)}
- D21H 19/36: Coatings with pigments (D21H19/66 takes precedence; metal powder D21H19/06)
- Y10T 428/24934: including paper layer
- Y10T 428/31866: Impregnated or coated cellulosic material
- Y10T 428/31993: Of paper
- D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A coated paper is white and glossy enough to give satisfaction as a printing paper, exhibits a good printability in offset sheet-fed printing and a high printing gloss, and does not degrade the print efficiency. The coated paper is characterized by having two or more coating layers composed mainly of a pigment and an adhesive on at least one side of a base paper. When ink is transferred onto the paper, the ink settability is relatively low in the early stage of the drying process and relatively high in the final stage.

## Claims

### Claim 1

A coated paper for printing applying two or more coating layers composed mainly of a pigment and an adhesive on at least one surface of a base paper, wherein pigment components of the outermost layer is composed of calcium carbonate of 5-70 mass % having an average particle diameter of 0.3-1.2 μm and kaolin of 30-95 mass % having an average particle diameter of 0.1-0.4 μm, and adhesive components of the outermost layer is composed of (a) water soluble adhesive, (b) styrene-butadiene copolymer latex containing acrylonitrile of 10-35 mass % in the ratio of monomer and having an average diameter of 50-120 nm, and (c) copolymer latex and other than the above (b), wherein when an amount of each fo the above (a), (b), and (c) contained in the coating layer is denoted as (S) mass parts, (LI) mass parts, and (L2) mass parts based on 100 mass parts of pigment components of the coating layer, respectively, the value of A can be obtained by the following equation:
A(mass part)=2×(S)+1.5×(L1)+1×(L2)
Wherein, 0≦(S)<6, 0≦(L1), 0≦(L2),
(S)+(L1)+(L2)≦16
Wherein the amount of pigment components having an average particle diameter of 0.4 μm or less contained in the outermost layer is
(i) 60 mass% or less of the total amount of pigment components, the value of A is within a range of 16-21,
(II) more than 60 mass % of the total amount of pigment components, the value of A is within a range of 19-24,
wherein 80-100 mass% of pigment components of an inner coating layer abutting on the outermost coating layer is composed of calcium carbonate having an average particle diameter of 0.1-1.2 μm while the mixture amount of adhesive components of the coating layer is 6-13 mass parts based on 100 mass parts of pigment components and the amount of water soluble adhesive contained in adhesive components is less than 6 mass parts based on 100 mass parts of pigment components.

### Claim 2 (depends on 1)

A coated paper for printing as defined in claim 1, wherein ink tack value measured 24.5 seconds after printing has been performed is 2.5N or less and ink tack value measured 790.2 seconds after printing has been performed is 4N or less.

### Claim 3 (depends on 1)

A coated paper for printing as defined in claim 1, wherein ink tack value measured 24.5 seconds after printing has been performed is 2.5N or less, ink tack value measured 669.6 seconds after printing has been performed is 3N or less and ink tack value measured 790.2 seconds after printing has been performed is 3N or less.

### Claim 4 (depends on 1)

A coated paper as defined in claim 1, wherein absorption coefficient Ka of the coating layers is within the range of 0.02-0.35 ml/(m2-ms1/2) when measured using Bristow tester and standard viscosity oil (JS2.5) defined in JIS Z8809-1992 as evaluation liquid, and wherein set-off density measured by a RI printability tester after printing on the coated paper with sheet ink for evaluating paper on condition that printing pressure is 980N and the amount of transferred ink is 4.2±0.1 g/m2is evaluated with a 256 gradation, the set-off density 1 minute after printing is 30 or less and the set-off density 6 minutes after printing is 230 or greater.

### Claim 5 (depends on 4)

A coated paper for printing as defined in claim 4, wherein the set-off density 1 minute after printing is 30 or less and the set-off density 6 minutes after printing is 245 or greater.

### Claim 6 (depends on 4)

A coated paper for printing as defined in claim 4, wherein the set-off density 1 minute after printing is 30 or less, 3 minutes after printing is 200 or greater, and 6 minutes after printing is 245 or greater.

### Claim 7 (depends on 4)

A coated paper for printing as defined in claim 4, wherein the set-off density 1 minute after printing is 28 or less, 3 minutes after printing is 200 or greater, and 6 minutes after printing is 245 or greater.

### Claim 8 (depends on 1)

A coated paper defined in claim 1, wherein absorption coefficient Ka of the coating layers is within a range of 0.02-0.35 ml/(m2-ms1/2) when measured using Bristow tester and standard viscosity oil (JS2.5) defined in JIS Z8809-1992 as evaluation liquid, wherein ink is a blend of sheet ink for evaluating paper of 80 mass % and ink solvent of 20 mass % printed on the coating layers on condition that printing pressure is 100N and the amount of transferred ink is 2.3±0.1 g/m2, wherein the maximum value of ink tack is between 24.5 seconds and 790.2 seconds after printing has been performed, wherein ink tack value measured 24.5 seconds after printing has been performed is 3N or less and ink tack value measured 790.2 seconds after printing has been performed is 4N or less.