JPH0585675B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a deinking aid for recycling used paper. More specifically, when deinking imitation waste paper, colored waste paper, leaflet waste paper, magazines, etc. using the flotation method, flotation/washing combination method, or water washing method, it is possible to obtain high whiteness and a small amount of dust and residual ink. This invention relates to a deinking aid for waste paper recycling, which is used together with a deinking agent to obtain deinked pulp. [Conventional techniques and problems] Recycling of imitation waste paper, colored waste paper, leaflet waste paper, magazines, etc. has been carried out for a long time, but recently, due to the shortage of pulp resources and the rise in its price, the effective use of waste paper has become difficult. The importance of deinked pulp is increasing, and the use of deinked pulp is also expanding to advanced uses. On the other hand, in recent years, waste paper has become increasingly difficult to deink due to changes in printing technology, printing methods, changes in printing ink components, and the use of waste paper that was not previously collected and used. Improvements have also been made to equipment to promote ink. Chemicals traditionally used to separate and remove ink and other impurities from waste paper include alkaline agents such as sodium hydroxide, sodium silicate, sodium carbonate, and sodium phosphate, hydrogen peroxide, hyposulfite, and hyposulfite. Bleach such as chlorate,
Along with sequestering agents such as EDTA and DTPA,
As a deinking agent, anionic activators such as alkylbenzene sulfonates, higher alcohol sulfate ester salts, α-olefin sulfonates, dialkyl sulfosuccinates, higher alcohols, EO (ethylene oxide) adducts of alkylphenols and fatty acids, E0・P0 (propylene oxide) adduct,
Nonionic surfactants such as alkanolamides have been used alone or in combination of two or more. However, it is difficult to completely separate the ink from the waste paper and remove the free ink through a flotation process and a washing process, and dust, that is, relatively large ink particles (100 to 4000 μm) in particular, is becoming a problem. In particular, in the case of coated paper (colored wood-free paper, etc.),
The surface of the cellulose aggregate is coated to give the paper the necessary properties. The necessary properties here include printability, gloss, surface strength, and the like. For example, in order to produce better printing, it is necessary to use a coating to fill the voids between the paper fibers, reduce the number of spots where ink does not adhere, and obtain a beautiful and sharp printing effect. As can be seen from the viewpoint of this printing effect, coating the paper surface is a common surface modification method. The coating mixture mainly consists of inorganic pigments such as clay, kaolin, calcium carbonate, titanium dioxide, etc., coloring pigments (ultramarine, chrome yellow, lake, dye, powdered metal), adhesives (starch, casein, soybean protein,
latex, acrylic resin, PVA, etc.), protein solubilizers (ammonia, sodium carbonate, sodium hydroxide, boric acid), additives (antifoaming agents, viscosity modifiers),
Waterproofing agents (urea resin, melamine-formaldehyde resin, hexamethylenetetramine resin, glyoxal, latex, formaldehyde, sulfuric acid salt), finishing agents (waxes, soaps), separating agents (condensed phosphates, etc.), etc. , the mixing ratio varies depending on the required characteristics and operability. Ink is printed onto the dry surface of this coating mixture. When deinking used colored paper, used leaflet paper, imitation used paper, magazines, etc., it is presumed that dust is generated because the coating layer on which ink has adhered to the surface cannot be decomposed by conventionally known deinking agents. Until now, there has been no effective means for dealing with dust, ie, ink with relatively large particle diameters (100 to 4000 μm). [Means for Solving the Problems] The present inventors have conducted intensive research to improve the above problems, and as a result, we have added the deinking aid for waste paper recycling of the present invention to the conventionally used deinking agent. The present invention was completed by discovering that a deinked pulp with high whiteness and less dust (ink particle size 100 to 4000 μm) can be obtained by using the above in combination. That is, the present invention provides general formulas (1) to (3)

【formula】

【formula】

[Effect]

Although the mechanism of the deinking aid for waste paper recycling of the present invention is not necessarily clear, although the giant ink particles peeled off from cellulose are further dispersed and made finer in the waste paper disintegration process, air bubbles are introduced in the flotation process. It is inferred that the heteroaggregation of the ink into the pulp is not inhibited, and furthermore, the ability to prevent the ink from re-adhering to the pulp is improved. Furthermore, in the water washing process, it is assumed that the ink particle size is controlled to a value that allows for good deinking using a valveless filter, extractor, etc. These are the ink dispersibility of the deinking aid for waste paper recycling of the present invention (meaning the dispersibility to the extent that it does not inhibit the heteroaggregation between air bubbles and ink);
This is presumed to be due to the protective colloid ability. [Examples] Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. The evaluation method was to measure the whiteness of the obtained pulp sheet using a colorimeter SM-3 manufactured by Suga Test Instruments Co., Ltd., and to use an image analyzer Luzex 500 (x4x) manufactured by Nippon Regulator Co., Ltd. Measurement of dust (number of remaining ink, ink particle size 100 μm or more) was adopted. Examples 1 to 7 After cutting the recovered colored paper to 2 x 5 cm, a certain amount of it was placed in a tabletop disintegrator, and water, sodium hydroxide (based on the raw material) at 1.0%, and sodium silicate (based on the raw material at 2.5%) were added thereto. %, 30% hydrogen peroxide (based on raw materials) 5.0%,
After adding 0.3% of a deinking agent (based on the raw material) and further adding 0.3% of a deinking aid for used paper recycling (based on the raw material), the pulp was disintegrated at a pulp concentration of 5% at a temperature of 50°C for 20 minutes. Thereafter, after aging at 50°C for 60 minutes, water was added to dilute the pulp concentration to 1.0%, and flotation treatment was performed at 30°C for 10 minutes. After concentrating the pulp slurry after flotation to a concentration of 6%, water was added to
% concentration and produced a pulp sheet using a TAPPI standard sheet machine. Comparative Examples 8 to 11 The same procedures as Examples 1 to 7 were carried out except that the deinking aid for waste paper recycling was not added. The results are shown in Table 1.

【table】

[Table] Examples 12 to 19 After cutting the recovered colored paper into 2 x 5 cm pieces, put a certain amount of it into a tabletop disintegrator, and add water, 1.0% sodium hydroxide (based on the raw material), and sodium silicate (based on the raw material). Raw materials) 1.0%, 30% hydrogen peroxide (based on raw materials) 2.0%,
Add 0.3% deinking agent (based on raw material) and 0.2% deinking aid for used paper recycling (based on raw material), pulp concentration is 5%, and after disintegration at a temperature of 55℃ for 15 minutes, the pulp concentration becomes 18%. Dehydrated with 80 mesh wire and heated at 60℃, 90℃.
The ripening process was carried out for 1 minute. After that, water was added so that the pulp concentration was 4%, and the pulp was disintegrated for 5 minutes using a tabletop disintegrator.Additionally, water was added to dilute the pulp to 1%, and then the pulp concentration was reduced to 10% using an 80 mesh wire. After repeating the washing process twice, a pulp sheet was prepared from the pulp slurry with a pulp concentration of 1% using a TAPPI standard sheet machine. Comparative Examples 20-22 The same methods as Examples 12-19 were carried out except that the deinking aid for waste paper recycling was not added. The results are shown in Table 2.

【table】

[Table] *5 Ethylenediaminetetra (methylenephosphonic acid) *6 Hexamethylenediaminetetra (methylenephosphonic acid) octasodium salt

Claims (1)

[Scope of Claims] 1. A deinking auxiliary agent for waste paper recycling comprising one or more compounds selected from the group of compounds represented by the following general formulas (1) to (3). [Formula] [Formula] [Formula] (In formulas (1) to (3), M represents hydrogen, an alkali metal, or ammonium, and n represents an integer from 1 to 10.)