JPH02229290A - Ink removal promoter of old paper - Google Patents

Abstract

PURPOSE:To obtain the promoter having high cohesive power to ink released from fiber, improved ink eliminating effects, providing ink removed pulp having high whiteness, containing an enzyme having activity of hydrolyzing ester bond of fatty acid ester. CONSTITUTION:The aimed ink removal promoter containing an enzyme (e.g. allyl esterase, carboxy esterase lipase especially thermostable alkali-resistant lipase) to hydrolyze ester bond of fatty acid ester.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a deinking accelerator for promoting the deinking action of a fatty acid ester deinking agent used for recycling waste paper.

[Conventional technology]

In order to obtain recycled pulp from used paper, it is necessary to deink the printed waste paper. There is a cleaning method in which ink particles are removed through the wires of a decker, extractor, inclined screen, etc., and the waste paper is digested under high temperature and high pressure in an earth cauldron. A method in which ink particles are removed by heat treatment at 50 to 60°C with an alkaline chemical and a deinking agent in a pulper, and then the ink particles are removed by performing the same operation as the above-mentioned cleaning method. After the treatment, air is blown into the treatment liquid to cause the ink to adhere to the bubbles and de-dry the ink, using a flotation method. For example, in the case of flotation, the steps are disintegration → dehydration → high concentration disintegration → ripening → flotation → washing → completion, but some of these steps may be omitted.

The functions required of the deinking agent differ depending on each process; in the defibration process, it penetrates into the fibers, emulsifies and disperses the ink, and prevents peeled ink from re-adhering to the fibers; in the dehydration process, it performs ink dispersion, and ink transfer to the fibers. Preventing ink from re-adhering to fibers in the high concentration disintegration process; Preventing ink from re-adhering to fibers and agglomerating ink in the aging process; Preventing ink from coagulating, foaming, and ink fibers in the flotation process Preventing re-adhesion to surfaces; preventing ink from scattering and foam-breaking during the cleaning process. As conventional deinking agents, in any of the above methods,
Fatty acid soaps, anionic surfactants such as alkyl sulfates, nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene polyoxypropylene alkyl ether, or these A mixture of fatty acid soaps has been used.4 However, although fatty acid soaps have excellent cohesive power against ink and have a high ability to remove ink by flotation,
Because the ink has low penetration into the fibers, most of the ink remains attached to the fibers. Furthermore, since the foaming power required for flotation is low, there is a drawback that it is necessary to add a foaming agent.

On the other hand, anionic surfactants and nonionic surfactants have excellent penetration, dispersion, and foaming power, but they have low cohesive power, resulting in low whiteness of recycled pulp and high foaming, so cleaning There are problems such as bubbles occurring during the paper making process when deinked waste paper pulp is used as raw material, wastewater treatment process, etc.

[Problem to be solved by the invention]

The purpose of the present invention is to improve the cohesive force for ink, improve the deinking effect, and obtain deinked waste paper pulp with high whiteness in order to solve the above-mentioned problems. The purpose of this invention is to provide a used paper deinking accelerator that suppresses foaming in wastewater treatment processes. [Means for Solving the Problems] The present invention is a waste paper deinking accelerator characterized by containing an enzyme having an activity of hydrolyzing the ester bonds of fatty acid esters.

The waste paper deinking accelerator of the present invention is an accelerator used to accelerate the deinking action of the deinking agent when deinking waste paper with a fatty acid ester deinking agent to produce dust-free waste paper pulp. An enzyme that can hydrolyze the ester bonds in the deinking agent or one that contains such an enzyme, and after the deinking agent (surfactant) that has a highly permeable ester bond is permeated into waste paper or pulp. It is used in combination with a fatty acid ester deinking agent to hydrolyze the ester bonds of the deinking agent and increase the cohesive force of the ink. The enzyme used as the waste paper deinking accelerator of the present invention is not particularly limited as long as it can hydrolyze the ester bonds in the deinking agent, and examples include esterases such as allyl esterase, carboxyesterase, and lipase. Among these, heat-resistant and alkaline-resistant lipases are preferred.

The deinking agent to be promoted by the waste paper deinking promoter of the present invention is a fatty acid ester surfactant that can remove ink from waste paper and is decomposed by the waste paper deinking promoter of the present invention. There are, for example, the following: It may be a polymer chain or a random polymer chain, and n represents a number greater than or equal to ]. ) (In the formula, Rl has 3 to 29 carbon atoms, particularly preferably 10 to 29 carbon atoms.
22 alkyl or alkenyl group, R2 represents an alkyl group or alkenyl group having 1 to 10 carbon atoms, particularly preferably a branched alkyl group or alkenyl group having 1 to 10 carbon atoms. ) (In the formula, R1 is an alkyl group having 8 to 22 carbon atoms, R2 is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, and n is a number of 1 or more.) (In the formula, R1 is an alkyl group having 7 to 22 carbon atoms. 21 alkyl group or alkenyl group, R1 is hydrogen or an alkyl group having 1 to 22 carbon atoms, alkenyl group or acyl group, AO has 2 to 22 carbon atoms
In the oxyalkylene chain of 4, when two or more types of oxyalkylene groups are present, a block chain (wherein R1 is an alkyl group having 7 to 21 carbon atoms, R2 is an alkyl group having 1 to 1 carbon atoms), R3 is an alkyl group of A hydrogen atom or an argyl group having 1 to 2 carbon atoms, n is a number greater than or equal to ].) The amount of deinking agent used is usually O. The range is from OX to 0.5% by weight. The waste paper deinking accelerator of the present invention is used in combination with a fatty acid ester deinking agent. First, the ink is peeled off and dispersed from the fibers using a deinking agent, and then the ester bonds of the deinking agent are hydrolyzed using the waste paper deinking accelerator of the present invention to liberate fatty acids that have excellent cohesive strength against ink. As a result, ink removal and agglomeration of the removed ink can be easily performed in a series of steps, and deinked waste paper pulp with a high degree of whiteness can be easily obtained. Furthermore, by decomposing the deinking agent, it is possible to suppress foaming in the process after adding the waste paper deinking accelerator. As a result, it is possible to improve cleaning efficiency, eliminate foam troubles in the papermaking process, and improve SS sedimentation in the wastewater treatment process, which can also eliminate problems caused by foaming.

The waste paper deinking accelerator of the present invention is used by being added to a process system for producing a deinked waste paper valve by deinking waste paper with a deinking agent. At the point of addition, a deinking agent is added to remove the ink from the fibers.
It may be added at any stage of the process after separation, for example, before or during the aging of the deinked waste paper treatment solution.
It can be added at any time, such as during the dilution stage of the ripening bulk, before flotation, before the washing step, in the finished chest and in the machine chest. When the purpose is to improve the cohesive force of ink, it is suitable to add it before ripening, during ripening, at the stage of diluting the aged pulp, and before the floatation agent and washing process. Further, when the purpose is to suppress foaming, it is suitable to add it to the finished chest or machine chest in addition to the above-mentioned time. Further, the desired amount may be added at one time, or may be added in several portions at multiple times. The amount of waste paper deinking accelerator to be added can be determined depending on the method of waste paper recycling or the conditions in each process, but the ratio of enzyme to waste paper is usually set to IOOOU/kg of waste paper.

It is preferable to add the enzyme under conditions that increase enzyme activity.
For example, in the case of a used paper deinking accelerator containing heat-resistant and alkaline-resistant lipase, the temperature is around 60°C. p} is preferably around 19.0 6 When using the waste paper deinking accelerator of the present invention, calcium chloride is added in order to further improve the cohesive force of the free fatty acids generated from the decomposition of the deinking agent to the ink. It may be added additionally, and a foaming agent may be added for the purpose of improving the ink removal effect by flotation.

〔Effect of the invention〕

By using the waste paper deinking accelerator of the present invention in combination with a fatty acid ester-based deinking agent in the process of producing waste paper deinking pulp, it increases the cohesive force for the ink peeled from the fibers and improves the deinking effect. This makes it possible to obtain deinked waste paper pulp with high whiteness, and also to suppress foaming during the cleaning process, papermaking process, wastewater treatment process, etc., and eliminate problems caused by foaming. [Examples] Examples of the present invention will be described below. Table 1 shows the enzymes used as waste paper deinking accelerators in the examples. Table 1 Example 1 (1) Disintegration of waste paper Waste paper containing 80% by weight of Mainichi, Asahi, and Yomiuri newspapers (all from 1 to 2 months after printing) and 20% by weight of leaflets was cut and mixed using a turbo power cutter. 10.5 g of 10% by weight sodium hydroxide, 21g of 10% by weight sodium silicate (No. 3). 7 g of 30% by weight hydrogen peroxide,
Add 28g of 1wt% deinking agent and 1265g of water, set the waste paper concentration to 5wt%, and add 3Q capacity of Hydrabulper (
After treatment at 55°C for 20 minutes at 9
32 g of water was added to dilute the waste paper concentration to 3% by weight, and the mixture was stirred for 5 minutes to perform complete metal disintegration. Next, sulfuric acid was added to the completely disintegrated waste paper to adjust the pH to 9.0. Next, after filtering through an 80 mesh sieve so that the waste paper concentration was 5% by weight, 200 U of enzyme was added and kept at 50° C. for 30 minutes. Next, ink was removed from a sample diluted to a waste paper concentration of 1% by weight by adding 4,666 g of water in the following manner.

(2) Removal of ink (A) Flotation method The sample from (1) above was injected into a 5Q photo floatator, floated for 10 minutes, the carbon aggregates in the upper layer were removed, and then manually using a Tappy standard sheet machine. A pulp sheet was obtained by extraction.

The deinking effect of this pulp sheet was evaluated by the following method. The results are shown in Table 2.

Deinking effect evaluation method Whiteness: The reflectance was measured using a photoelectric reflectance meter, where the reflectance of magnesium oxide was defined as lOO. The values in the table are the average values of 5 points x 5 sheets.

b value: Based on the Lab color difference formula of JIS Z8730.

Count the number of remaining inks using a microscope with a magnification of 40.
It was converted into a value per 1d. Note that the enzyme activity was measured by the following method.

Enzyme activity measurement method: Rotary stirring method was used. That is, the diameter is 32 mm and the height is 76 mm.
50mM phosphate buffer (pH 6.5) in a 50mM reaction vessel
5 mQ. 1 d of substrate and 0.1 l of enzyme solution were added, stirred at 520 rpm with a magnetic stirrer in an incubator at 37° C., and reacted for a certain period of time.

After the reaction, add 20tQ of ethanol to stop the enzyme reaction.
pH the extracted free fatty acids with 1/20N KOH solution.
It was titrated to 10.0. Enzyme activity (U: unit) was defined as the amount of enzyme that releases 1 μmol of fatty acid per minute using olive oil as a substrate under the above reaction conditions. The activity (U/mQ) of the enzyme solution is determined by the following formula.

In the blind test, the enzyme solution was added after ethanol was added, and the titration was carried out in the same manner.

(B) Cleaning method The sample from (1) above was filtered through an 80 mesh sieve, water was added so that the concentration of recycled pulp was 1% by weight, and carbon was removed by filtration through an 80 mesh sieve. .

Water was added to the washed regenerated pulp so that the pulp concentration was 1% by weight, and the pulp was hand-sheeted using a Tappy standard sheet machine to obtain a pulp sheet.

The deinking effect of this pulp sheet was evaluated in the same manner as the blotting method. The results are shown in Table 2.

Comparative Example 1 The same procedure as in Example 1 was carried out except that no enzyme was added in the disintegration treatment of used paper in Example 1. The results are shown in Table 2. Example 2 The pulp slurry after flotation in Example 1 was filtered through a mesh sieve, and the filtrate was used as a sample.

After heating sample 600+sQ to 30°C, it was placed in a transparent synthetic resin cylinder and circulated with a pump at 1/min for 5 minutes. The amount of bubbles generated on the surface of the sample liquid was read from the scale on the cylinder wall, and measured in volume units (ml2), which was defined as the foaming amount. The results are shown in Table 3.

Comparative Example 2 The same procedure as Example 2 was carried out except that the bulp slurry after flotation in Comparative Example 1 was used. The results are shown in Table 3.

Table 3 $I S. A. A1: et}lxκen(PO)e4(
Decoy) 2, SAA2 HC. ,H,,COO(Fo).
．． (EO),sS AA 3: C,,H,,Coo
(PO), (EEO)3.

Circle: propylene oxide sachet: ethylene oxide Based on the above results, the examples have higher whiteness and b value, lower number of remaining ink, and significantly smaller foaming amount than comparative examples, and have a deinking promotion effect and foaming suppression. It can be seen that the effect is excellent.

Agent: Patent attorney Sei Yanagi Hara

Claims (1)

[Claims] (1) A used paper deinking accelerator characterized by containing an enzyme having the activity of hydrolyzing the ester bonds of fatty acid esters.