Title:
METHOD FOR BLEACHING PULP
Document Type and Number:
WIPO Patent Application WO/2005/121442
Kind Code:
A1
Abstract:
A method for bleaching a pulp, which comprises irradiating an acid-treated and washed pulp with an ultraviolet and/or visible light having a wavelength of 100 to 400 nm under an alkaline condition, preferably at a pH in the range of 10 to 13; the bleaching method, wherein the acid treating is carried out under the condition of a pH of 1 to 6 and a temperature of 80°C or higher; and the bleaching method, wherein the light is irradiated in the presence of at least one compound selected from the group of a reducing agent, a peroxide and a hydrogen-donating organic compound; and a highly white chemical pulp which has a ISO whiteness of 88 % or higher and exhibits a decreasing rate for the whiteness in a prescribed discoloration test of 1.0 % or less. The above bleaching method is a technology having been attained by further developing a conventional acid treatment or light irradiation of a pulp, and it reduces the use of a chlorine-containing chemical and is markedly efficient and more efficient as compared to a conventional technology. The above pulp is reduced in the load on the environment, is free from discoloration, and is an excellent pulp having high whiteness.
Inventors:
Miyawaki, Shoichi c/o Nippon Paper Industries Co. (Ltd. Pulp and Paper Research Laboratory 21-1,
Oji 5-chome, Kita-k, Tokyo 02, 11400, JP)
Kurosu, Kazuhiro c/o Nippon Paper Industries Co. (Ltd. Pulp and Paper Research Laboratory 21-1, Oji 5-chome, Kita-k, Tokyo 02, 11400, JP)
Ochi, Takashi c/o Nippon Paper Industries Co. (Ltd. Pulp and Paper Research Laboratory 21-1, Oji 5-chome, Kita-k, Tokyo 02, 11400, JP)
Kurosu, Kazuhiro c/o Nippon Paper Industries Co. (Ltd. Pulp and Paper Research Laboratory 21-1, Oji 5-chome, Kita-k, Tokyo 02, 11400, JP)
Ochi, Takashi c/o Nippon Paper Industries Co. (Ltd. Pulp and Paper Research Laboratory 21-1, Oji 5-chome, Kita-k, Tokyo 02, 11400, JP)
Application Number:
PCT/JP2005/010521
Publication Date:
December 22, 2005
Filing Date:
June 08, 2005
Export Citation:
Assignee:
NIPPON PAPER INDUSTRIES CO., LTD. (4-1 Oji 1-chome, Kita-ku Tokyo, 02, 11400, JP)
Miyawaki, Shoichi c/o Nippon Paper Industries Co. (Ltd. Pulp and Paper Research Laboratory 21-1, Oji 5-chome, Kita-k, Tokyo 02, 11400, JP)
Kurosu, Kazuhiro c/o Nippon Paper Industries Co. (Ltd. Pulp and Paper Research Laboratory 21-1, Oji 5-chome, Kita-k, Tokyo 02, 11400, JP)
Ochi, Takashi c/o Nippon Paper Industries Co. (Ltd. Pulp and Paper Research Laboratory 21-1, Oji 5-chome, Kita-k, Tokyo 02, 11400, JP)
Miyawaki, Shoichi c/o Nippon Paper Industries Co. (Ltd. Pulp and Paper Research Laboratory 21-1, Oji 5-chome, Kita-k, Tokyo 02, 11400, JP)
Kurosu, Kazuhiro c/o Nippon Paper Industries Co. (Ltd. Pulp and Paper Research Laboratory 21-1, Oji 5-chome, Kita-k, Tokyo 02, 11400, JP)
Ochi, Takashi c/o Nippon Paper Industries Co. (Ltd. Pulp and Paper Research Laboratory 21-1, Oji 5-chome, Kita-k, Tokyo 02, 11400, JP)
International Classes:
D21C9/10; D21C9/16; D21C9/10; D21C9/16; (IPC1-7): D21C9/10
Attorney, Agent or Firm:
Shamoto, Ichio (YUASA AND HARA, Section 206 New Ohtemachi Bldg., 2-1,
Ohtemachi 2-chome, Chiyoda-k, Tokyo 04, 10000, JP)
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