JP2703858B2 - Recovering used paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recycling used paper.

[0002]

2. Description of the Related Art Conventionally, used paper generated in offices and the like includes: Newspaper, 2. Copy paper, 3. Pressure-sensitive paper, heat-sensitive paper, etc.Newspaper is difficult to deink when trying to regenerate in the usual way because the printing method has been replaced by the offset method, and copy paper is printed by electrostatic recording using toner ink. Because of the increase in the size of the ink, the removal of the ink becomes inadequate when trying to regenerate in the usual way.In addition, pressure-sensitive paper and thermal paper use dyes and precursors that have become dyes but have not yet been dyed. It has a large amount of a coating layer containing it, and if it is regenerated in the usual way, it will develop color due to heat, pressure and friction during papermaking, deteriorating the quality of the product. There was a problem that had to be.

[0003] In order to solve such a problem, pressure-sensitive paper,
A method of recycling used paper including thermal paper and newspapers has been developed,
The process and the apparatus are as shown in FIGS. 5 and 6 and are composed of pre- and post-processes I and II. In the pre-process I, the waste paper is put into the pulper 1 and a slurry is applied so that it can be pumped by adding chemicals and heat. Then, sand, metal, and other contaminants are removed with a coarse cleaner 2, then concentrated to about 25 to 35%, kneaded with a kneader 3, and the ink on the used paper is separated by mechanical force and immersed. In the tower, immersion treatment is carried out with a chemical solution mainly composed of caustic soda to make the pulp thicker, and a diluent is added to dilute the pulp to 1%. Then, fine bubbles are put into the water mixed with the chemicals by the flotator 4 and flotation is performed to remove the ink together with the foams. To complete the de-inked pulp by.

[0004]

However, such a regenerating method comprises the preceding and following steps I and II as described above. In particular, in the preceding step I, a disintegration treatment using the pulper 1 and a concentration treatment before the kneading treatment are performed. An immersion treatment or the like using an immersion tower is required, and the equipment for that purpose is large in size, requires a large installation area, and has a problem that a large amount of equipment cost and operation cost are required.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the conventional waste paper recycling method, to obtain recycled waste paper free from coloring due to residual pigment, and to perform a disintegration treatment using a pulper. There is no need for concentration treatment before the kneading treatment and immersion treatment using the immersion tower, etc., and there is no need for a large facility for it and a large installation area for installing it. An object of the present invention is to provide a method for recycling used paper without requiring equipment costs and operating costs.

[0006]

According to the present invention, in order to achieve the above object, the invention of claim 1 includes 8% or less of pressure-sensitive paper and thermal paper, and 20% or more of newspaper. Using office waste paper as a raw material, immersed in a pulp concentration of 12 to 30% without disintegration, and at a temperature of 45 to 60 ° C, 1% in terms of pulp NaOH
The following alkalis, surfactants mainly composed of surfactants consisting of polyoxyalkylene derivatives of fatty acids and fats of 0.3% or less based on pulp, and immersed in a chemical solution containing hydrogen peroxide of 0.5% or less based on pulp for 6 to 18 hours Processing, then kneading with a kneader to separate the ink on the waste paper with mechanical force,
The diluting solution is added to dilute the pulp to 1%, and then roughing, flotation, fine selection, light foreign matter removal and concentration treatment are sequentially performed to complete the deinked pulp. According to a second aspect of the present invention, in the first aspect, the kerosene emulsified with the surfactant is added to the pulp at 0.05 to 0.4 immediately before the flotation.

[0007]

In the present invention as described above, waste paper containing pressure-sensitive paper, heat-sensitive paper, and newspaper is sent directly to the immersion tower in a pre-processed state at a predetermined ratio in a separated air-dried state without being disintegrated and immersed. At a predetermined temperature, a chemical solution containing a surfactant mainly composed of a surfactant composed of a deoxygenating agent composed of a polyoxyalkylene derivative of an alkali, a fatty acid and a fat and oil, and having a higher ink-collecting property than dispersibility. Perform a immersion treatment for a predetermined time, thereby minimizing the release of the dye from the pressure-sensitive paper and the heat-sensitive paper, preventing the dye from being eluted and dyed by excessive treatment, and thereafter, in the same manner as in the conventional method. A kneading process is performed to separate the toner ink and offset ink on the waste paper by mechanical force, disperse the hard-to-separate ink, add a diluent to dilute the pulp, and then screen in the subsequent process. After the roughing to remove the Degomi,
Fine bubbles are put into water mixed with chemicals, flotation is performed to remove the ink together with the bubbles, and garbage remaining after the careful selection and removal of light foreign substances is removed and concentrated to complete deinked pulp.

[0008]

FIG. 2 shows a first embodiment of the present invention.
20% or less of pressure-sensitive paper and thermal paper
% Of the waste paper containing newspapers of not less than 10% is separated and sent to an air cyclone 10 by wind transport or the like in an air-dried state while separating and exhausting the gas. And immersed in a pulp concentration of 12 to 30% without disintegration, at a temperature of 45 to 60 ° C with respect to pulp NaO
The main component is a surfactant composed of an alkali of 1% or less in terms of H, a polyoxyalkylene derivative of a fatty acid and a fat or oil of 0.3% or less with respect to pulp, and a deinking agent having a higher ink-collecting property than permeation and dispersibility. Surfactant, 0.5 against pulp
% Of hydrogen peroxide is sprayed evenly over the used paper and immersed for 6 to 18 hours to minimize the release of dye from pressure-sensitive paper and thermal paper. The release prevents the dye from being eluted and dyed. Then, in the same manner as in the conventional method, kneading is performed by a kneader 3 to separate the ink on the waste paper by mechanical force, and then sent to a diluting tank 6 to add a diluting liquid to dilute the pulp to 1%. Since it is the same as the post-process II, it will be described with reference to FIG. 6. After performing a rough selection for removing dust on a screen, fine bubbles are added to water mixed with a chemical by a flotator 4, Flotation is performed to remove the ink together with the foam, and the screen 5 is used to remove the refuse remaining after the rough selection and the removal of the light foreign substances, and then concentrated to complete the deinked pulp. The second embodiment shown in FIG. 3 is provided with a load cell 13 instead of the weighing conveyor 11 of the first embodiment, and the third embodiment shown in FIG. In this configuration, the measuring conveyor 14 is used as a conveyor for feeding used paper to the immersion tower 12. The weighing conveyors 11 and 14 and the load cell 13 do not need to be provided when weighing is unnecessary, and may be a disperser instead of the kneader 3. In the above case, the kerosene emulsified with the surfactant may be added to the pulp at 0.05 to 0.4 immediately before the flotation.

[0009]

The present invention is as described above. According to the first aspect of the present invention, waste paper containing 8% or less of pressure-sensitive paper and heat-sensitive paper and 20% or more of newspaper is used as a raw material, and the pulp concentration is 12% or less. ~ 30%
Immersion without disintegration at a temperature of 45-60 ° C with pulp N
A surfactant mainly containing a surfactant of 1% or less in terms of aOH, a surfactant composed of a fatty acid and a polyoxyalkylene derivative of fats and oils of 0.3% or less with respect to pulp, and a chemical solution containing 0.5% or less of hydrogen peroxide with respect to pulp. Immersion treatment for ~ 18 hours, then kneading treatment, diluting liquid is added to dilute the pulp to 1%, then roughing, flotation, fine selection, light foreign matter removal and concentration treatment are sequentially performed to deinked pulp The invention of claim 2 is the invention of claim 1, wherein the kerosene emulsified with the surfactant is added to the pulp at 0.05 to 0.4 immediately before the flotation, and there is no color development due to the residual dye. Recycled paper pulp can be obtained, and the treatment does not require disintegration using a pulpper, concentration before kneading, and immersion using an immersion tower. Because, without the need for large installation area for the large-scale facilities for its installation it is effective that requires inexpensive without requiring a great deal of equipment cost and operating cost.

[Brief description of the drawings]

FIG. 1 is a process chart of an embodiment of the present invention.

FIG. 2 is a partial longitudinal front view of a main part of the first embodiment of the present invention.

FIG. 3 is a partial longitudinal front view of a main part of a second embodiment of the present invention.

FIG. 4 is a partial longitudinal front view of a main part of a third embodiment of the present invention.

FIG. 5 is a drawing similar to FIG. 1 of a conventional method of recycling used paper.

FIG. 6 is a schematic layout view of the above device.

[Explanation of symbols]

 I Pre-process II Post-process 3 Kneader 4 Flotator 12 Immersion tower

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoto Sugiyama 111-4, Zenza-cho, Shizuoka City, Shizuoka Prefecture (72) Inventor Katsuhiro Tamura 9-5 Oiwahoncho, Shizuoka City, Shizuoka Prefecture (72) Inventor Matsuo Kurosawa Shimizu, Shizuoka Prefecture 2-6-1, Shibukawa Fuji Seiko Co., Ltd. Shimizu Plant (72) Inventor Ikuo Seino 2-1-1 Tanidocho, Tanashi-shi, Tokyo Sumitomo Heavy Industries, Ltd. Tanashi Works (72) Inventor Taku Sato Tokyo 2-1-1, Yadocho, Tsudanashi-shi Sumitomo Heavy Industries, Ltd. Tanashi Factory (56) References JP-A-53-52704 (JP, A) JP-A-4-361678 (JP, A) JP-A Heisei 3-287889 (JP, A) JP 64-3991 (JP, B2)

Claims (2)

(57) [Claims] 1. Including pressure sensitive paper and thermal paper of 8% or less, 20%
The waste paper containing the above-mentioned newspaper was sent directly to the immersion tower by wind power or the like while it was in an air-dried state, and the pulp concentration was 12%.
Soak without disaggregation at ~ 30%, alkali at 1% or less of pulp equivalent to NaOH at temperature of 45 ~ 60 ° C, 0.3% to pulp
Surfactants based on surfactants comprising the following fatty acids and polyoxyalkylene derivatives of fats and oils, based on pulp:
Perform immersion treatment in a chemical solution containing 5% or less of hydrogen peroxide for 6 to 18 hours, then perform kneading treatment, add a diluent to dilute the pulp to 1%, and then perform rough selection, flotation, fine selection, A method for recycling waste paper, comprising sequentially performing light foreign matter removal and concentration treatment to complete deinked pulp. 2. Immediately before the flotation,
Kerosene emulsified with the above surfactant is added to pulp 0.05 to 0.
The method of claim 1 wherein 4% is added.