JP2746563B2 - Cleaning agent for paper and pulp manufacturing process and cleaning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning agent and a cleaning method for a paper and pulp manufacturing process in a paper and pulp mill, and more particularly to a cleaning agent and a cleaning method for a paper and pulp manufacturing process which often adhere to members and walls in a water system. The present invention relates to a cleaning agent and a cleaning method capable of easily removing and dispersing sludge-like stains that cause various troubles to the outside of the system.

[0002]

2. Description of the Related Art In the paper and pulp manufacturing process, sludge-like dirt adheres and accumulates on members, wall materials, especially wall materials of wire pits and pipeline surfaces in the process water system, causing various obstacles. . Soil that adheres and accumulates in such a paper and pulp manufacturing process water system includes pitch components from virgin pulp, fine fibers, printing ink from waste paper, clay as a filler, diatomaceous earth, talc, calcium carbonate, calcium sulfate, Such as barium sulfate, rosin size as a sizing agent, alkyl ketene dimer, alkenyl succinic anhydride, sulfate band, polyacrylic resin as a paper strength enhancer, urea formaldehyde resin, melamine-formaldehyde resin, starch, cationized starch, etc. It has a complex composition consisting of metal salts such as iron, calcium, and magnesium from service water, and slime caused by bacteria, mold, etc., and in a typical industrial water system such as a general cooling water system due to the specificity of its derived components. Sludge-like stains generated by Ku is different. However, it directly mixes with paper and pulp materials as products, causing serious obstacles such as deterioration of product quality and production efficiency. This problem has been exacerbated with an increase in papermaking speed.

[0003] Therefore, conventionally, a cleaning treatment has been performed in which sludge-like dirt is peeled and dispersed at regular intervals to remove the sludge-like dirt out of the system. Specific cleaning methods include, for example, cleaning with various surfactants, hydrochloric acid, and sulfamine sulfate. Acid washing with acid, etc.
Alkali washing with soda ash, caustic soda, etc., washing with organic solvents such as kerosene, light oil, xylene, and hydrochloric acid solvents are known. Recently, washing using an acrylic acid polymer has also been proposed (JP-A-62-21).
No. 893).

[0004]

However, among the conventional cleaning methods, cleaning with various surfactants is liable to foam during use, and has almost no effect on sticky sludge containing a polyvalent metal salt. Absent. Acid cleaning is highly corrosive to metals and cannot be used in practice. Cleaning with an organic solvent requires careful attention to fire and toxic gases, and is subject to restrictions on handling.

[0005] Therefore, in the past, alkali cleaning has been widely used in such systems, but the cleaning effect is not sufficiently satisfactory. In particular, sludge containing a large amount of metal salts such as silica and magnesium is used. And
The sludge containing cationized starch, which has recently been widely used as a paper-strengthening agent, has a disadvantage that the washing effect is insufficient and a long washing time and manual work are required.

[0006] Further, even in the above-mentioned cleaning method using an acrylic acid polymer (Japanese Patent Laid-Open No. 62-21893), the cleaning effect of sludge containing metal salts and cationized starch as described above is insufficient. Was. The present invention has been made under such circumstances, and is particularly excellent in cleaning effect, and can efficiently peel off and remove hard-to-peel sludge containing metal salts and cationized starch as described above in a short time. It is intended to provide an agent and a cleaning method.

[0007] It is known that some of the organic phosphonic acids used in the present invention have an effect of dissolving and removing scale generated on the inner surface of a boiler or a heat exchanger based on the chelating action thereof ( JP-A-51-9029). However, it is not known to be used for removing sludge in the paper / pulp manufacturing process, and it is completely known that it has a remarkable effect not only for dissolving and removing but also for removing and dispersing and removing outside the system. Absent.

[0008]

According to the present invention, the following general formula (I):

[0009]

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Wherein A is a divalent lower hydrocarbon group which may be substituted with a hydroxyl group or an amino group, or a divalent group represented by the following formula:

[0011]

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(Wherein X is a phosphono lower alkyl group, 1
+ N is 1 to 3 and m is an integer of 0 to 4)]. Further, according to the present invention, there is provided a method for washing a paper / pulp manufacturing process using the organic phosphonic acid of the above formula (I) or a salt thereof.

According to the present invention, the above-mentioned hard-to-peel sludge can be efficiently peeled and dispersed by adding the organic phosphonic acid of the above formula (I) to the paper / pulp manufacturing process water and circulating the same. It is based on the discovery that it can be removed outside. The above-mentioned organic phosphonic acids have heretofore been known as compounds having a chelating action. However, other known chelating agents such as EDTA, 2-phosphono-butane-1,2,4-tricarboxylic acid and tripolyphosphoric acid are known. Even if sodium is used, the above effects cannot be obtained. Therefore, the cleaning effect exhibited in the present invention is unique to the organic phosphonic acid of the formula (I).

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the organic phosphonic acid of the formula (I) of the present invention, the lower hydrocarbon group and the lower alkyl group mean a hydrocarbon group having 1 to 4 carbon atoms and an alkyl group. , Ethylene, propylene, trimethylene and tetramethylene groups and methyl, ethyl, propyl and butyl groups. Specific examples of such organic phosphonic acids include 1-hydroxyethylidene-1,1-
Examples thereof include diphosphonic acid, ethylenediaminetetra (methylenephosphonic acid), hexamethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid), and nitrilotrimethylphosphonic acid. Among these, it is preferable to use 1-hydroxyethylidene-1,1-diphosphonic acid, nitrilotrimethylphosphonic acid or ethylenediaminetetra (methylenephosphonic acid) from the viewpoint of availability. Further, as these salts, easily water-soluble salts are used, alkali metal salts are suitable, and potassium salts and sodium salts are preferably used. Of course, these compounds and salts may be used as a mixture.

The washing in the paper / pulp manufacturing process in the present invention can be performed by flowing washing water to which the above-mentioned organic phosphonic acid or a salt thereof is added, through the paper / pulp manufacturing process system. More specifically, after removing the paper / pulp manufacturing process water, by circulating washing water in which the above-mentioned organic phosphonic acid or its salt is added and dissolved in water such as industrial water or tap water, in this process system. It can be carried out. By this treatment, in the paper / pulp manufacturing process system, in particular, sludge-like dirt adhering to the wall surfaces of wire pits and pipelines gradually peels off from the wall surface and disperses in the washing water, and by continuing this, the sludge-like The dirt is almost completely removed from the wall surface and becomes a floc-like state in the washing water. Then, by discharging the washing liquid out of the system, dirt in the paper / pulp manufacturing process system is removed outside the system.

In carrying out the cleaning method of the present invention, it is desirable that the cleaning water is alkaline in terms of the cleaning effect.
The pH is particularly preferably 9 to 13, and an alkali agent such as caustic soda and caustic potash is used in combination as necessary.
In the present invention, the concentration of the organic phosphonic acid or a salt thereof in the washing water is not particularly limited, and is usually from 0.06 to
It is selected within the range of 60% by weight, and is preferably 0.1 to 5% by weight in terms of cost and cleaning effect. Further, the washing time, that is, the flow time of the washing water, is a time during which the sludge-like dirt adhered to the system can be sufficiently separated and dispersed in a floc-like manner. Is enough. In any case, the cleaning process can be performed in a shorter time as compared with the conventional cleaning method, and dirt that is difficult to remove can be removed. The washing is usually carried out at normal temperature, but may be carried out by heating as needed, whereby the washing time can be further shortened.

The washing liquid in the washing method of the present invention can be prepared by directly adding the above-mentioned organic phosphonic acids and, if necessary, an alkali agent. However, a liquid in which these are dissolved or dispersed in water in advance is used. Is convenient and easy to handle. At this time, other additives, such as a surfactant and a chelating agent, which do not impair the effects of the present invention, may be incorporated into the liquid preparation.

[0018]

[Example] A plurality of stainless steel test pieces (300 × 10
(0 × 1.5 mm) was suspended, and papermaking (using sulphate using talc as a filler and cationized starch as a paper strength agent) was performed. As a result, after one week, sludge-like dirt was firmly adhered to the surface of each test piece (average amount of adhering agent: 16 mg / cm ² ).

The test pieces were collected and the composition of the stain was examined. The results are shown below. Loss on burning 30.8 (% by weight) SiO ₂ (from filler) 39.8 CaO (from filler) 0.7 MgO (from filler) 20.5 Al ₂ O ₃ 7.5 (Iodine starch reaction positive) Each of the attached test pieces is immersed in a predetermined cleaning liquid (at a constant temperature of 40 ° C.), and the cleaning liquid is agitated.
In principle, the state of peeling of surface dirt after 4 hours was examined.

[0020] The results, together with the percentage of the cleaning liquid composition and exfoliated area used in Table 1. In the table, A of compound (I) indicates 1 -hydroxyethylidene-1,1-diphosphonic acid, B indicates nitrilotrimethylsulfonic acid, and C indicates ethylenediaminetetra (methylenephosphonic acid). All percentages are by weight.

[0021]

[Table 1]

As is clear from the above table, even when a cleaning solution using sodium hydroxide was used, the peeling ratio was less than 5% (Comparative Example 1), and the removal rate was lower than that of EDTA, sodium tripolyphosphate and PBTC. No improvement in the peeling effect was observed even when a complex chelating agent was used in combination (Comparative Example 2,
3). On the other hand, when the organic phosphonic acid of the compound (I) was used, an excellent peeling effect was obtained by itself (Example 1), and the peeling effect was improved by making the compound alkaline (Examples 2 to 2). 4) It can be seen that an excellent peeling effect is achieved.

[0023]

According to the cleaning agent and the cleaning method of the present invention, sludge-like stains that are specifically generated in the paper / pulp manufacturing process can be efficiently removed and removed. Sludge-like dirt, which has been difficult and has to be removed manually, can be peeled and removed in a short time.

Therefore, the cleaning agent and the cleaning method of the present invention are extremely useful in a paper / pulp manufacturing process.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-50-160502 (JP, A) JP-A-62-65728 (JP, A)

Claims (4)

(57) [Claims] 1. 1-hydroxyethylidene-1,1-di
A cleaning agent for a paper / pulp manufacturing process comprising a phosphonic acid or a salt thereof as an active ingredient. 2. The cleaning agent according to claim 1, further comprising an alkaline agent. 3. The method according to claim 1, wherein said 1-hydro
Cleaning in a paper / pulp manufacturing process characterized by separating and removing sludge adhering in a paper / pulp manufacturing process system by flowing washing water to which xylethylidene-1,1-diphosphonic acid or a salt thereof is added. Method. 4. The cleaning method according to claim 3, wherein the cleaning water is made alkaline.