JP2017190539A - Deinked pulp production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deinked pulp production method that can produce high-quality deinked pulp by promoting the peeling and micronization of ink for the waste paper printed by various printing methods and inks.SOLUTION: In the deinked pulp production method, a solution comprising waste paper 1 is irradiated with ultrasound in (I) peeling and micronization step.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing deinked pulp.

  Recycling waste paper is an important issue for environmental protection. Currently, deinked pulp that has been recycled from used newspaper, magazine paper, and colored waste paper is reused as a raw material for paper products, etc., but the paper industry is striving to improve the waste paper usage rate. Depending on the printing method, it is inevitable to use waste paper (low-grade waste paper) that is difficult to deink by ordinary deinking processing. Further, the demand for the quality of deinked pulp has become higher, and it has become important to maintain the quality of deinked pulp by using advanced low-grade waste paper.

  In general, the deinked pulp manufacturing process includes a flotation process in which ink is peeled and refined from waste paper, and then the peeled ink is adsorbed by bubbles and then floated and removed.

  For example, as a conventional method for producing deinked pulp, a deinking method is known in which floss generated in the flotation process or the like is separated and removed by an ink separation process including an ultrasonic treatment process (for example, , See Patent Document 1).

  Also, the deinking device is characterized in that ultrasonic waves are radiated into the liquid from which the used paper is unwound to generate a shocking sound pressure and bubbles, thereby separating and removing the fiber material and colored contaminants from the unwound used paper. Is also known (see, for example, Patent Document 2).

JP 2004-19025 A JP 61-201093 A

  By the way, in order to effectively remove the ink in the flotation step or the like and obtain a high-quality deinked pulp, in the step before the flotation, the ink adhered to the pulp in advance is sufficiently peeled off and sufficiently It is necessary to make it fine.

  However, in the above-mentioned Patent Documents 1 and 2, since the ultrasonic treatment is performed during the flotation process or instead of the flotation process, it essentially contributes directly to the separation and miniaturization of the ink. is not.

  Accordingly, the present invention has been made in view of the above-mentioned problems of the prior art, and promotes the peeling and miniaturization of ink with respect to waste paper printed by various printing methods and inks, thereby removing high quality. It aims at providing the manufacturing method of the deinked pulp which can obtain black pulp.

  As a result of intensive studies to achieve the above object, the present inventors can easily achieve the above object by irradiating the solution containing waste paper with ultrasonic waves in the peeling / miniaturization process. As a result, the present invention has been completed.

  That is, the method for producing deinked pulp disclosed herein includes a disaggregation step, and a separation / miniaturization step for separating and miniaturizing ink from waste paper, and an ink separated / miniaturized in the separation / miniaturization step. A discharge step of discharging, and ultrasonic irradiation is performed in the peeling / miniaturization step.

  In a preferred embodiment, the peeling / miniaturization step includes at least one of a high concentration treatment step, an aging step, and a dilution step, and the ultrasonic irradiation includes the high concentration treatment step, the aging step, and the dilution step. It is performed in at least one of the steps.

  In a preferred embodiment, the peeling / miniaturizing step includes the dilution step, and the ultrasonic irradiation is performed in the dilution step.

  In a preferred embodiment, a nonionic surfactant and / or a higher fatty acid or a salt thereof is added in at least one of the peeling / miniaturizing step and the discharging step.

  In a preferred embodiment, a deinking agent containing a compound represented by the following general formula (1) is added in at least one of the peeling / miniaturization step and the discharging step.

(In General Formula (1), R ¹ , R ² , R ³ , and R ⁴ are each independently an alkyl group having 1 to 22 carbon atoms, a hydroxyalkyl group; an alkenyl group having 2 to 22 carbon atoms, and a hydroxyalkenyl group. A benzyl group; a glycidyl group; a group represented by the following general formula (2), wherein (A ¹ O) is an alkyleneoxy group having 2 to 4 carbon atoms, and Y is hydrogen or an acyl having 1 to 8 carbon atoms; N is an integer of 2 to 200 in terms of the number of repeating units of A ¹ O, and the number and carbon number of R ¹ , R ² , R ³ and R ⁴ having 1 to 4 carbon atoms and 2 carbon atoms. The sum of the number of hydroxyalkenyl groups of ˜4 and the number of n of A ¹ O is an integer of 0-200, and X ⁻ is a counter ion.)

  In a preferred embodiment, the ink is an active energy ray curable ink and / or an oxidation polymerization type ink.

  According to the present invention, there is provided a deinked pulp manufacturing method capable of obtaining high-quality deinked pulp by promoting the peeling and miniaturization of ink with respect to waste paper printed with various printing methods and inks. It becomes possible to do.

FIG. 1 is a flowchart for explaining the steps of a method for producing deinked pulp according to an embodiment of the present invention. FIG. 2 is a diagram schematically illustrating a state in which ink is in close contact with pulp fibers in waste paper. FIG. 3 is a diagram schematically showing a state in which disaggregation of pulp fibers and partial peeling of the ink have advanced from the state of FIG. FIG. 4 is a diagram schematically showing a state in which the ink is further peeled and miniaturized from the state of FIG.

  Hereinafter, embodiments of the present invention will be described in detail. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its use.

(Embodiment)
<Recycled paper and ink>
The waste paper used as the raw material for the deinking pulp is not particularly limited, and any printed paper may be used. Specifically, for example, newspapers, magazines, OA papers, flyers, colored paper, imitation paper, heat and pressure sensitive recording paper, sublimation transfer, printed by all methods such as letterpress printing, offset printing, gravure printing, and ink jet printing. Examples include high-quality waste paper such as paper, medium-quality waste paper, and low-quality waste paper.

  The printed ink is, for example, an active energy ray curable type such as UV curable ink, an oxidation polymerization type blended with dry oil or semi-dry oil such as flaxseed oil or soybean oil such as sheet-fed ink, osmotic dry type, off It includes all types of ink, such as heat drying type such as ring ink, and thermosetting type such as metal ink.

  The active energy ray-curable ink is an ink that does not require heat energy and is simply cured by irradiating the active energy ray. As the active energy ray, visible light, UV, EB, LED, infrared ray, X-ray, α Examples of the active energy ray curable ink include UV curable ink, EB curable ink, LED curable ink, and visible light curable ink. In any of the inks, a polymerization reaction occurs due to irradiation with active energy rays and is cured. The active energy ray curable ink includes hybrid type active energy ray curable ink with other types such as thermosetting ink.

  In recent years, active energy curable inks such as UV curable inks, which are increasingly used, can be peeled off from pulp fibers relatively easily, but are difficult to miniaturize because the ink film is strong. It is difficult to remove and remove sufficient deinking properties. In addition, oxidation polymerization inks containing drying oil or semi-drying oil such as linseed oil and soybean oil used in newspapers, etc., become more resinous with the progress after printing, and the adhesion to pulp becomes higher. The ink is difficult to peel from the pulp, and it is difficult to obtain sufficient deinking properties. According to the method for producing deinked pulp according to the present embodiment, the ink printed on the waste paper can be peeled off from the pulp fiber by ultrasonic irradiation in the peeling / miniaturizing step before the discharging step, and can be made fine. Even if it is an active energy ray curable ink or an oxidation polymerization type ink, the ink can be effectively removed from the pulp fiber. In general, various types of ink are mixed in waste paper, and active energy ray-curable ink may be included in the waste paper. In addition, the method for producing deinked pulp according to the present embodiment is also useful for used paper containing varnish for improving ink adhesion and active energy ray-curable varnish that is difficult to refine.

<Method for producing deinked pulp>
As shown in FIG. 1, the method for producing deinked pulp generally includes (I) a peeling / miniaturizing step for peeling / miniaturizing ink from waste paper, and (II) a discharging step for discharging the peeled ink. Including.

  More specifically, the (I) peeling / miniaturization step is first an essential step, a disaggregation (pulping) step (S1), and then an optional step, a coarse selection step (S2), a high concentration treatment step ( S3), aging step (S4), dilution step (S5) and the like are included.

  In addition, the (II) discharge step includes a flotation step (S6) as an essential step and a cleaning step (S7) as an optional step.

  As shown in FIG. 2, for example, the waste paper 1 has a structure in which the ink 3 is in close contact with the intertwined pulp fibers 2.

  The disaggregation step (S1) is a step for performing physical operations on the waste paper 1 to unravel the pulp fibers 2 of the waste paper 1 and to peel and refine the ink 3 from the pulp fibers 2. Specifically, the waste paper 1 in a state as shown in FIG. 2 is put together with water and necessary additives into, for example, a disaggregator, and the pulp fibers 2 of the waste paper 1 are unraveled by a stirring force. As the pulp fibers 2 are disaggregated, the ink 3 that is in close contact with the pulp fibers 2 is partially peeled and miniaturized, and the state shown in FIG. 3 is obtained. In the disaggregation step (S1), from the viewpoint of promoting disaggregation of the pulp fiber 2, as described later, an alkali agent or the like can be added as an additive.

  Next, the rough selection step (S2) is a step for removing large foreign matters contained in the used paper 1 in advance, and it is possible to remove rough unnecessary materials using, for example, a screen or the like.

  The high-concentration treatment step (S3) is a step in which the waste paper 1 is squeezed and stirred to peel and refine the ink 3 that has not been peeled or refined from the waste paper 1 in the disaggregation step (S1). Specifically, for example, after the used paper liquid is dehydrated by a dehydrator, a kneading operation is performed to separate and miniaturize the ink 3.

  The ripening step (S4) is a step of further promoting the peeling / miniaturization of the ink 3 by leaving the disaggregated waste paper 1 as it is, and is achieved by leaving it, for example, by heating or bleaching. Is done. The waste paper 1 from which the ink 3 has been peeled and miniaturized has a state as shown in FIG. 4, for example.

  The dilution step (S5) is a step for facilitating the removal of the ink 3 from the pulp fiber 2 in the subsequent (II) discharge step, particularly the flotation step (S6). In order to efficiently remove the ink 3 from the waste paper liquid obtained through the conversion step, water is added to, for example, a pulp concentration of about 1% by mass to make the mixture uniform.

  (II) The flotation step (S6), which is an essential step of the discharging step, is a step of removing the peeled ink 3 by adsorbing it to the bubbles and then floating. Specifically, for example, the diluted waste paper liquid is put together with necessary additives in a flowator or the like and foamed, and the peeled / miniaturized ink 3 is adsorbed to the generated bubbles and lifted up, whereby the ink 3 is removed. The The washing step (S7) is a step of removing the ink 3 floating in the water by repeating the operation of adding water to the used paper 1 and stirring and then squeezing.

<Ultrasonic irradiation>
Here, the manufacturing method of the deinked pulp according to the present embodiment includes (I) a peeling / miniaturization step that is a step prior to the (II) discharge step, in particular, in the present embodiment, (I) a peeling / miniaturization step. The ultrasonic irradiation is performed in at least one of the disaggregation step, the rough selection step, the high concentration treatment step, the aging step, and the dilution step. That is, as shown in FIG. 1, (I) the disaggregation step (S1) of the peeling / miniaturization step, the rough selection step (S2), the high concentration treatment step (S3), the aging step (S4), and the dilution step (S5). In this case, ultrasonic irradiation can be performed. In FIG. 1, during the disaggregation step (S1), the coarse selection step (S2), the high concentration treatment step (S3), the ripening step (S4), and the dilution step (S5), the ultrasonic irradiation is performed respectively. A sound wave U1, an ultrasonic wave U2, an ultrasonic wave U3, an ultrasonic wave U4, and an ultrasonic wave U5 are shown. Note that the ultrasonic wave U2 (ultrasonic irradiation during the coarse selection step (S2)) is an ultrasonic wave applied to the waste paper liquid before the operation of removing the foreign matter by passing the waste paper liquid through a filter or the like in the coarse selection step (S2). It means performing irradiation. Further, the ultrasonic wave U3 (ultrasonic irradiation during the high concentration treatment step (S3)) includes performing ultrasonic irradiation on the used paper liquid after the rough selection step (S2).

  The ultrasonic irradiation is performed in at least one of the ultrasonic waves U1 to U5 from the viewpoint of effectively promoting the peeling and miniaturization of the ink. That is, ultrasonic irradiation may be performed at any one of the ultrasonic waves U1 to U5, or ultrasonic irradiation may be repeatedly performed at several stages.

  According to this configuration, since the ultrasonic irradiation is performed in the step prior to the (II) discharging step, the flotation step (in the state where the peeling / miniaturization of the ink 3 from the pulp fiber 2 is sufficiently promoted) This can be used for S6), whereby a high-quality deinked pulp from which ink 3 has been sufficiently removed can be obtained.

  Preferably, (II) discharge from the ultrasonic wave U3 performed after the coarse selection step, from the viewpoint that if the ink is refined before the coarse selection step (S2) for the purpose of removing large foreign matters, the ink that can be removed cannot be removed. It is desirable to perform ultrasonic irradiation in the ultrasonic wave U5 before the process.

  More preferably, for the waste paper liquid in which the separation / miniaturization of the ink has progressed to some extent in (I) the disaggregation step (S1), the high concentration treatment step (S3), and the aging step (S4) of the separation / miniaturization step It is desirable to perform ultrasonic irradiation with the ultrasonic wave U5 from the viewpoint of being able to perform ultrasonic irradiation, further ensuring the transmission of ultrasonic waves, and effectively promoting the peeling and miniaturization of ink.

  The frequency of the ultrasonic wave is not particularly limited, but is preferably 5 kHz to 3000 kHz, more preferably 15 kHz to 500 kHz, and still more preferably 15 kHz to 100 kHz from the viewpoint of promoting peeling / miniaturization.

  Moreover, although the amplitude of an ultrasonic wave is not specifically limited, 1-100 micrometers is preferable from a viewpoint of promoting peeling and refinement | miniaturization, and 5-80 micrometers is more preferable.

  The ultrasonic generator is not particularly limited, and examples thereof include a horn type and a sweep type. The sweep type is preferable when aiming at an effect in a wide range, and the horn type is preferable in a relatively narrow range.

  The pulp concentration at the time of ultrasonic irradiation is not particularly limited, but is preferably 40% by mass or less, more preferably 30% by mass or less, and more preferably 10% by mass based on the waste paper dispersion from the viewpoint of ultrasonic transmission. The following is even more preferable, and 5% by mass or less is particularly preferable. Therefore, from the viewpoint of effectively accelerating the peeling / miniaturization of the ink 3, (II) obtained at the stage of the ultrasonic wave U5 in the dilution process, which is the process immediately before the discharge process, that is, in the aging process (S4). It is preferable to perform ultrasonic irradiation on the diluted dispersion obtained by adding water to the used paper dispersion and diluting it.

<Nonionic surfactant>
Next, the nonionic surfactant added to the manufacturing method of the deinked pulp which concerns on this embodiment is demonstrated.

  The nonionic surfactant can be added in at least one of (I) peeling / miniaturizing step and (II) discharging step. The nonionic surfactant can optimize the foaming property, and can improve the ink removing effect in the flotation.

  The nonionic surfactant is not particularly limited, and specific examples include higher alcohol alkylene oxide adducts, fatty acid esterified products of higher alcohol alkylene oxide adducts, alkyl or alkenylphenol alkylene oxide adducts, fatty acid alkylenes. Oxide adduct, higher fatty acid esterification product of polyhydric alcohol alkylene oxide adduct, aliphatic amine alkylene oxide adduct, fatty acid amide alkylene oxide adduct, polyoxypropylene alkylene oxide adduct polyalkylene glycol type; glycerol fatty acid ester And polyhydric alcohol types of pentaerythritol fatty acid ester, sorbitol fatty acid ester, and sucrose fatty acid ester. The higher alcohols mentioned here are usually linear or branched unsaturated or saturated higher alcohols having 8 to 22 carbon atoms, and the alkyl or alkenyl phenols are usually linear or branched alkyl or alkenyl phenols having 6 to 22 carbon atoms. The fatty acid is usually an unsaturated or saturated fatty acid having 10 to 22 carbon atoms, the polyhydric alcohol is usually a polyhydric alcohol having 3 to 12 carbon atoms, and the aliphatic amine is usually a straight chain having 8 to 22 carbon atoms. A chain or branched unsaturated or saturated aliphatic amine, and from the viewpoint of ink removability (ink collecting property, ink aggregation property) in flotation, higher alcohol alkylene oxide adduct, higher alcohol alkylene oxide adduct Fatty acid esterified product of polyhydric alcohol and alkylene oxide adduct of higher fatty acid esterified product are preferable. Following general formula (3), a nonionic surfactant of the following general formula (4) is more preferable. These can use 1 type (s) or 2 or more types.

(However, R ⁵ is an alkyl group having 8 to 22 carbon atoms, an alkenyl group, a hydroxyalkyl group, or a hydroxyalkenyl group, A ² O is an alkyleneoxy group having 2 to 4 carbon atoms, and s is a repetition of A ² O. The number of units, which is an integer from 1 to 240.)

(However, R ⁶ and R ⁷ are each independently an alkyl group having 1 to 22 carbon atoms or a hydroxyalkyl group; an alkenyl group having 2 to 22 carbon atoms or a hydroxyalkenyl group, at least one having 8 to 22 carbon atoms. A ² O is an alkyleneoxy group having 2 to 4 carbon atoms, t is the number of repeating units of A ² O, and R ⁶ and R ⁷ are a hydroxyalkyl group or hydroxyalkenyl group having 2 to 4 carbon atoms. (It is an integer of 1 to 240 regardless of the case.)

In general formulas (3) and (4), examples of A ² O include an ethyleneoxy group and a propyleneoxy group, and these may be used alone or in combination of two or more. When two or more kinds are used, the addition form of alkylene oxide is not limited, and examples thereof include random addition, block addition, and a method of mixing random and block.

In general formula (3), R ⁵ is preferably an alkyl group having 12 to 22 carbon atoms or a hydroxyalkyl group, and more preferably an alkyl group having 18 to 22 carbon atoms or a hydroxyalkyl group. s is preferably 15 to 220, more preferably 30 to 200.

In general formula (4), at least one of R ⁶ and R ⁷ is preferably an alkyl group having 12 to 22 carbon atoms or a hydroxyalkyl group, and more preferably an alkyl group having 18 to 22 carbon atoms or a hydroxyalkyl group. t is preferably 15 to 220, more preferably 30 to 200, regardless of whether R ⁶ or R ⁷ is a hydroxyalkyl group or hydroxyalkenyl group having 2 to 4 carbon atoms.

<Amount of nonionic surfactant used>
The amount of the nonionic surfactant used in the present embodiment is preferably 0.001 to 10% by mass, preferably 0.005 to 5% by mass, based on the dry weight of the used paper, from the viewpoint of deinking property and cost. % Is more preferable, and 0.01 to 1% by mass is particularly preferable.

<Higher fatty acid or salt thereof>
Next, the higher fatty acid added to the manufacturing method of the deinked pulp which concerns on this embodiment, or its salt is demonstrated.

  The higher fatty acid or a salt thereof can be added in at least one of (I) peeling / miniaturization step and (II) discharging step, and can also be used in combination with the nonionic surfactant. . Higher fatty acids or salts thereof can optimize foaming properties when used in combination with the nonionic surfactant, and can improve the ink removal effect in flotation.

  Examples of higher fatty acids or salts thereof include higher fatty acids of the following general formula (5) or salts thereof. These can use 1 type (s) or 2 or more types.

(However, R ⁸ is an alkyl group, alkenyl group, hydroxyalkyl group, or hydroxyalkenyl group having 7 to 21 carbon atoms, and Z ⁺ is a hydrogen ion or a counter ion.)

In general formula (5), R ⁸ is preferably an alkyl group having 11 to 21 carbon atoms, an alkenyl group, a hydroxyalkyl group, or a hydroxyalkenyl group, and an alkyl group having 17 to 21 carbon atoms, an alkenyl group, a hydroxyalkyl group, or a hydroxy group. More preferred is an alkenyl group. Z is not particularly limited, and examples thereof include alkali metals such as sodium and potassium; alkaline earth metals such as calcium and magnesium; alkanolamines such as triethanolamine and diethanolamine.

<Amount of higher fatty acid or salt thereof>
The amount of the higher fatty acid or salt thereof used in the present embodiment is preferably 0.001 to 10% by mass, preferably 0.005 to 5% by mass, based on the dry weight of the used paper, from the viewpoint of deinking property and cost. Is more preferable, and 0.01 to 1% by mass is particularly preferable.

<Deinking agent: compound represented by general formula (1)>
The method for producing deinked pulp according to the present embodiment includes a deinking process including a compound represented by the following general formula (1) in at least one of (I) peeling / refining step and (II) discharging step. It is preferable to add a black ink. Accordingly, it is possible to improve the deinking property by effectively accelerating the peeling / miniaturization of the ink and / or the removal of the ink. 1 type (s) or 2 or more types can be used for the compound shown by following General formula (1).

(In General Formula (1), R ¹ , R ² , R ³ , and R ⁴ are each independently an alkyl group having 1 to 22 carbon atoms, a hydroxyalkyl group; an alkenyl group having 2 to 22 carbon atoms, and a hydroxyalkenyl group. A benzyl group; a glycidyl group; a group represented by the following general formula (2), wherein (A ¹ O) is an alkyleneoxy group having 2 to 4 carbon atoms, and Y is hydrogen or an acyl having 1 to 8 carbon atoms; N is an integer of 2 to 200 in terms of the number of repeating units of A ¹ O, and the number and carbon number of R ¹ , R ² , R ³ and R ⁴ having 1 to 4 carbon atoms and 2 carbon atoms. The sum of the number of hydroxyalkenyl groups of ˜4 and the number of n of A ¹ O is an integer of 0-200, and X ⁻ is a counter ion.)

In general formula (1), the alkyl group, alkenyl group, hydroxyalkyl group, and hydroxyalkenyl group represented by R ¹ , R ² , R ³ , and R ⁴ may be linear or branched.

In the compound represented by the general formula (1), R ¹ is preferably an alkyl group having 1 to 22 carbon atoms or a hydroxyalkyl group; an alkenyl group having 2 to 22 carbon atoms or a hydroxyalkenyl group from the viewpoint of miniaturization of the ink. C 6-20 alkyl group, alkenyl group, hydroxyalkyl group, hydroxyalkenyl group are more preferable, and C 8-18 alkyl group, alkenyl group, hydroxyalkyl group, hydroxyalkenyl group are more preferable.

R ² , R ³ and R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms or a hydroxyalkyl group; an alkenyl group having 2 to 4 carbon atoms or a hydroxyalkenyl group; a benzyl group; a glycidyl group; ), N is an integer of 2 to 50, and the number of hydroxyalkyl groups having 1 to ⁴ carbon atoms and the number of hydroxyalkenyl groups having 2 to 4 carbon atoms and the number of A ¹ O of R ² , R ³ and R ⁴ . It is preferable that the sum total with the number of n is an integer of 1-50, a C1-C4 alkyl group, a hydroxyalkyl group; a C2-C4 alkenyl group, a hydroxyalkenyl group; a benzyl group; a glycidyl group In the general formula (2), n is an integer of 2 to 25, and the number of the hydroxyalkyl group having 1 to ⁴ carbon atoms and the number of the hydroxyalkenyl group having 2 to 4 carbon atoms of R ² , R ³ and R ^4. And the number of n in A ¹ O The sum is more preferably an integer of 1 to 25.

  The compound of the general formula (1) of the present embodiment is considered to be particularly useful when the ink is peeled off / miniaturized from waste paper using an active energy ray curable ink. Such an ink contains an acrylic monomer that is cured by active energy rays, and the cured ink contains an acrylic resin. The compound of the general formula (1) of the present embodiment is considered to function as a catalyst for decomposing this acrylic resin (cleaving the ester bond). Therefore, the ink peeled from the waste paper can be decomposed and miniaturized. In addition, since the active energy ray curable ink is a hard ink, it is easily peeled off from the waste paper in the disaggregation step (S1) and the like, so the main function of the compound of the general formula (1) of this embodiment is to decompose the ink. It is presumed to be miniaturized.

  In addition, since the compound of general formula (1) of this embodiment is thrown into water and functions as a catalyst for decomposing an acrylic resin (cleaving an ester bond), four groups bonded to nitrogen are used. The effect can be improved by appropriately adjusting the kind and length of these and the number of alkyleneoxy groups. Specifically, it is necessary to balance so as not to be biased toward either one of hydrophobicity and hydrophilicity, and it is preferable that the inside of both the aqueous phase and the organic compound phase can be moved.

Therefore, from the viewpoint of improving the function as the catalyst, more preferably, R ¹ is an alkyl group having 6 to 20 carbon atoms, a hydroxyalkyl group, an alkenyl group, or a hydroxyalkenyl group, and R ² , R ³ , R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms or a hydroxyalkenyl group, an alkenyl group having 2 to 4 carbon atoms or a hydroxyalkenyl group, a benzyl group, a glycidyl group, or a group represented by the general formula (2). A ¹ O is an alkyleneoxy group having 2 to 4 carbon atoms, n is an integer of 2 to 15 in terms of the number of repeating units of A ¹ O, and R ¹ , R ³ , and R ⁴ have 1 carbon atom. sum of the number of the number of a ^{1 O} n-number and hydroxy alkenyl group having 2 to 4 carbon atoms and 4 hydroxyalkyl group may be a group which is an integer of 1 to 15. X ⁻ is a counter ion.

Examples of A ¹ O include an ethyleneoxy group, a propyleneoxy group, and a butyleneoxy group, and these may be used alone or in combination of two or more. When two or more kinds are used, the addition form of alkylene oxide is not limited, and examples thereof include random addition, block addition, and a method of mixing random and block. A ¹ O is preferably an ethyleneoxy group and / or a propyleneoxy group from the viewpoint of ink peeling and miniaturization. Y is preferably hydrogen.

X ⁻ is a counter ion and is not particularly limited. For example, alkyl sulfate ions such as methyl sulfate ion and ethyl sulfate ion; alkylbenzene sulfonate ions such as paratoluene sulfonate ion; halides such as chloride ion And ions.

  It does not specifically limit as a manufacturing method of the compound of General formula (1), It is obtained by a well-known manufacturing method.

  The compound represented by the general formula (1) may be used as it is, but can be used by dissolving, emulsifying or dispersing in water or an organic solvent. Moreover, it is preferable to use with the below-mentioned alkali agent, nonionic surfactant, higher fatty acid, or its salt. Furthermore, other deinking agents may be added.

  Although it does not specifically limit as a kind of said organic solvent, C1-C6 lower alcohols, such as methanol, ethanol, and propanol; The alkylene oxide adduct of the said lower alcohol; Ethylene glycol, diethylene glycol, propylene glycol, etc. Glycol; 3-methyl-3-methoxybutanol and the like.

<Use amount of the compound represented by the general formula (1)>
The amount of the compound represented by the general formula (1) is preferably 0.0001 to 10% by mass, preferably 0.0005 to 5% by mass, based on the dry weight of the used paper, from the viewpoint of deinking property and cost. Is more preferable, and 0.001-1 mass% is especially preferable.

  Next, the chemical | medical agent which can be used for the manufacturing method of the deinking pulp which concerns on this embodiment is demonstrated.

<Alkaline agent>
In the method for producing deinked pulp, an alkali agent is usually added to remove ink from used printing paper. In the method for producing deinked pulp according to the present embodiment, the detachment / miniaturization of the ink is promoted by the ultrasonic treatment, and therefore it is not necessary to add an alkali agent. Thereby, it is possible to suppress a decrease in pulp quality and a decrease in yield, such as a decrease in volume feeling and a decrease in strength due to excessive decomposition and refinement of pulp fibers by an alkali agent. Further, from the viewpoint of further promoting pulp disaggregation and ink peeling / miniaturization, an appropriate amount of an alkali agent may be added. In particular, by performing ultrasonic irradiation after adding an alkali agent, the peeling and miniaturization of ink can be effectively promoted by the synergistic effect of both. The alkaline agent is not particularly limited, and examples thereof include inorganic alkaline agents such as sodium hydroxide, potassium hydroxide, sodium silicate, and sodium carbonate. These can use 1 type (s) or 2 or more types.

<Amount of alkali agent used>
The amount of the alkali agent used varies depending on the type of the used waste paper. The pH after addition of the alkali agent is preferably 6 or more, more preferably 8 or more, and particularly preferably 9 or more, from the viewpoint of promoting pulp disaggregation and ink peeling / miniaturization. Further, the pH after the addition of the alkali agent is preferably 13 or less, more preferably from the viewpoint of suppressing a decrease in pulp quality and a decrease in yield, such as a decrease in volume feeling and a decrease in strength due to the use of a large amount of the alkali agent. 12.7 or less, particularly preferably 12.5 or less.

<Nonionic surfactant, addition time of compound represented by general formula (1), alkali agent, higher fatty acid or salt thereof>
The addition time of the nonionic surfactant, the compound represented by the general formula (1), the alkali agent, the higher fatty acid or a salt thereof is not particularly limited, but from the viewpoint of deinking property, the production of the deinked pulp is performed. In the process, it is preferable to add in any one or more of (I) peeling / miniaturization process and (II) flotation process S6 in the discharging process. (II) (I before the discharging process) ) More than one of the plurality of steps constituting the peeling / miniaturization step, that is, the disaggregation step S1, the coarse selection step S2, the high concentration treatment step S3, the ripening step S4 and the dilution step S5. preferable. Further, the alkali agent is preferably added at the same time as or before the addition of the compound represented by the general formula (1). In particular, from the viewpoint of promoting the pulp disaggregation, (I) the disaggregation in the peeling / miniaturization step. It is preferable to add in the step (S1). Moreover, when the white water generated in the method for producing deinked pulp is reused, it may be added to the reused white water.

<Other drugs>
In some cases, the method for producing deinked pulp can further include an anionic surfactant. Anionic surfactants include sulfate ester of higher alcohol alkylene oxide adduct, phosphate ester of higher alcohol alkylene oxide adduct (monoester, diester, triester), alkyl sulfate ester, alkyl phosphate ester Compound (monoester, diester, triester), alkyl sulfonate and the like.

  Further, known agents used in the conventional deinking process, specifically, bleaching agents such as hydrogen peroxide, sodium percarbonate, sodium hypochlorite, hydrosulfite, thiourea dioxide; chelating agents; Hydrogen stabilizers; other known deinking agents; foaming agents; pitch control agents; disaggregation accelerators and the like can be added as desired.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

<Compound of general formula (1)>
The compounds of the general formula (1) used in Examples and Comparative Examples are shown in Table 1 below. Table 2 shows the nonionic surfactants used in Examples and Comparative Examples. In Table 1, R ^{2 to} R ⁴ are substituents. In Tables 1 and 2, EO and PO as substituents represent an ethyleneoxy group and a propyleneoxy group, respectively, and the numbers indicate the number of moles added. In Table 1, for example, Compound No. When (EO) ₁₅₀ H is described across the items of R ³ and R ⁴ as in (E1), it means that 150 mol of ethylene oxide has been added to R ³ and R ⁴ in total.

Example 1
In a JIS standard disaggregator, 100 g of UV curable ink-printed waste paper (hereinafter referred to as waste paper) obtained from a printing company, 0.2% by weight of compound (P1) (vs. waste paper), and 5% by weight of waste paper with a concentration of waste paper I put it to become. Sodium hydroxide is not added. Moreover, as shown in Table 3, the pH of the treatment tank was 7.8. Next, it disaggregated for 5 minutes at the temperature of 40 degreeC. Thereafter, the JIS standard disaggregator was stopped, and ultrasonic irradiation was performed for 2.5 minutes at a frequency of 19.5 KHz and an amplitude of 60 μm using an ultrasonic homogenizer (ULTRASONIC HOMOGENIZER US-600E manufactured by Nippon Seiki Seisakusho Co., Ltd.) (shown in FIG. 1). Thus, the ultrasonic irradiation during the disaggregation process was set to ultrasonic wave U1, and the operation of the JIS standard disaggregator was started again and disaggregated for 5 minutes (total disaggregation process for 10 minutes). Thereafter, foreign matters are removed through a flat screen (coarse selection step), dehydrated with a 200 mesh wire net, concentrated to a pulp concentration of 15%, and heated at a temperature of 40 ° C. with a PFI mill (manufactured by Kumagai Riki) at 1000 rpm. The treatment was performed for a minute (high concentration treatment step). Next, after ripening at 60 ° C. for 4 hours in a constant temperature bath (aging step), water at 40 ° C. was added and stirred so that the concentration of the used paper was 1% by mass. Then, pass through an air volume of 3.0 L / min with a Denver-type floatator (manufactured by Kumagai Riki Co., Ltd.) for 5 minutes while scraping off the floss (bubbles on the water surface and ink adhering to the bubbles) every minute. Flotation treatment was performed (flotation process). The waste paper obtained after the flotation treatment was adjusted to pH 5.5 with an aluminum sulfate solution, and hand-made with a round paper machine at a basis weight of 200 g / m ² according to JIS P-8209 (1994). A press treatment was performed, and the sample was dried at 105 ° C. for 5 minutes with a drum dryer to obtain a test paper after flotation.

(Examples 2 to 5)
In Examples 2 to 5, ultrasonic irradiation was performed during the coarse selection process (ultrasonic wave U2) and during the high-concentration treatment process (after processing with the PFI mill for 30 seconds, after stopping the PFI mill and performing ultrasonic irradiation, The operation of the PFI mill was started and the treatment was performed for 30 seconds, during which the ultrasonic irradiation was set to ultrasonic wave U3), during the ripening process (ultrasonic wave U4), during the dilution process (while adding 40 ° C. water and stirring) A test paper after flotation was obtained by performing the same treatment as in Example 1 except that the ultrasonic irradiation was changed to ultrasonic wave U5).

(Examples 6 and 7)
In Examples 6 and 7, the same treatment as in Example 5 was performed, except that the ultrasonic irradiation time was changed to 5 minutes and 10 minutes, respectively, and test sheets after flotation were obtained.

(Examples 8 to 11)
In Examples 8 to 11, when used paper was put into a JIS standard disintegrator, sodium hydroxide was added at 0.1% by mass, 0.5% by mass, 1.0% by mass, and 2.5% by mass (for used paper). Except for the addition, the same treatment as in Example 5 was performed to obtain a test paper after flotation. The pH of the treatment tank after addition of sodium hydroxide was 10.1, 11.5, 12.2, and 12.5, respectively.

(Examples 12 and 13)
In Examples 12 and 13, the same treatment as in Example 11 was performed except that the time of ultrasonic irradiation was changed to 1.5 minutes and 5 minutes, respectively, and test sheets after flotation were obtained.

(Example 14)
In Example 14, a test paper after flotation was obtained by performing the same process as in Example 11 except that the amplitude of the ultrasonic wave was changed to 40 μm.

(Example 15)
In Example 15, the disaggregation process (ultrasonic wave U1), the coarse selection process (ultrasonic wave U2), the high concentration treatment process (ultrasonic wave U3), the aging process (ultrasonic wave U4), and the dilution process (ultrasonic wave). A test paper after flotation was obtained by performing the same treatment as in Example 11 except that ultrasonic irradiation was performed for 0.5 minutes in each step of U5).

(Example 16)
In Example 16, the disaggregation process (ultrasonic wave U1), the coarse selection process (ultrasonic wave U2), the high concentration treatment process (ultrasonic wave U3), the aging process (ultrasonic wave U4), and the dilution process (ultrasonic wave). A test paper after flotation was obtained by performing the same treatment as in Example 11 except that each of the steps U5) was subjected to ultrasonic irradiation for 1 minute.

(Example 17)
Example 17 was carried out except that ultrasonic irradiation was performed for 0.5 minutes in each step of the disaggregation process (ultrasonic wave U1), the high concentration treatment process (ultrasonic wave U3), and the dilution process (ultrasonic wave U5). The same treatment as in Example 1 was performed to obtain a test paper after flotation.

(Example 18)
Example 18 is the same as Example 11 except that ultrasonic irradiation was performed for 1 minute in each step of the disaggregation process (ultrasonic wave U1), the high concentration treatment process (ultrasonic wave U3), and the dilution process (ultrasonic wave U5). A test paper after flotation was obtained by performing the same treatment as in Example 1.

(Example 19)
In Example 19, when sodium hydroxide was added, instead of the compound (P1), 0.2% by mass of the compound (E1) (to old paper) was added, and during the disaggregation process (ultrasonic wave U1) A test paper after flotation was obtained by performing the same treatment as in Example 11 except that the ultrasonic irradiation was performed for 2.5 minutes.

(Example 20)
Example 20 is the same as Example 20 except that 0.2% by mass (based on waste paper) of the compound of the general formula (1) (E3) was added instead of the compound of the general formula (1) (E1) when sodium hydroxide was added. The same treatment as in No. 19 was performed to obtain a test paper after flotation.

(Examples 21 to 23)
In Examples 21, 22, and 23, when sodium hydroxide was added, instead of the compound (P1), the compound of the general formula (1) was changed to 0.2% by mass (relative to each of (E1), (E3), and (E5)). Waste paper) was added, and the same treatment as in Example 11 was performed except that ultrasonic irradiation was performed for 2.5 minutes during the high concentration treatment step (ultrasonic wave U3) to obtain a test paper after flotation.

(Examples 24-28)
In Examples 24, 25, 26, 27, and 28, when sodium hydroxide was added, the compound of the general formula (1) was replaced with (E1), (E2), (E3), (E4) instead of the compound (P1), respectively. , (E5), except that 0.2% by mass (for used paper) was added, and the same treatment as in Example 11 was performed to obtain a test paper after flotation.

(Example 29)
Example 29 was the same as that of Example 29 except that 0.2% by mass of compound (E1) (to waste paper) and 0.1% by mass (to waste paper) of compound (P1) were added when sodium hydroxide was added. The same treatment as in Example 19 was performed to obtain a test paper after flotation.

(Example 30)
Example 30 was the same as that of Example 30 except that 0.2% by mass of compound (E3) (to waste paper) and 0.1% by mass (to waste paper) of compound (P1) were added when sodium hydroxide was added. The same treatment as in Example 11 was performed to obtain a test paper after flotation.

(Example 31)
In Example 31, sodium hydroxide was added, except that 0.2% by mass of compound (E1) (0.12% of waste paper) and 0.1% by weight of compound (P2) (against waste paper) were added. The same treatment as in Example 19 was performed to obtain a test paper after flotation.

(Example 32)
In Example 32, when sodium hydroxide was added, 0.2% by mass of compound (E3) (to waste paper) and 0.1% by mass of compound (P2) (to waste paper) were added. The same treatment as in Example 11 was performed to obtain a test paper after flotation.

(Examples 33 to 39)
Examples 33 to 39 are the same as in Examples 1 to 3, except that the used UV curable ink-printed waste paper was replaced with newspaper waste paper (newspaper / city flyer 70/30, newspapers printed with oxidative polymerization ink). The same treatment as in No. 7 was performed to obtain a test paper after flotation. The pH of the treatment tank was 7.7.

(Examples 40 to 43)
In Examples 40 to 43, the used UV curable ink-printed waste paper was replaced with newspaper waste paper (newspaper / city flyer 70/30), and the addition amounts of sodium hydroxide were 0.05% by mass and 0.25% by mass, respectively. , 0.5% by mass, 1.0% by mass (against used newspaper), the same treatment as in Examples 8 to 11 was performed to obtain test paper after flotation. In addition, pH of the processing tank after sodium hydroxide addition was 9.0, 11.0, 11.5, and 12.2, respectively.

(Examples 44 to 62)
In Examples 44 to 62, the used UV-curable ink-printed waste paper was replaced with newspaper waste paper (newspaper / city flyer 70/30), and the amount of sodium hydroxide added was changed to 1.0 mass% (against waste paper). Otherwise, the same treatment as in Examples 12 to 30 was performed to obtain a test paper after flotation. In addition, pH of the processing tank after sodium hydroxide addition was 12.2.

(Example 63)
In Example 63, when sodium hydroxide was added, the compound of the general formula (1) (E4) was 0.2% by mass (against waste paper), the compound (P1) was 0.05% by mass (against waste paper), the compound A test paper after flotation was obtained by carrying out the same treatment as in Example 33 except that 0.05 mass% (P3) was added.

(Example 64)
In Example 64, when sodium hydroxide was added, compound (g) of general formula (1) was 0.2% by mass (against waste paper), compound (P1) was 0.05% by mass (against waste paper), compound A test paper after flotation was obtained in the same manner as in Example 43, except that 0.05 mass% (P3) was added.

(Comparative Example 1)
In Comparative Example 1, a test paper after flotation was obtained by performing the same treatment as in Example 1 except that ultrasonic irradiation was not performed.

(Comparative Example 2)
In Comparative Example 2, a test paper after flotation was obtained by performing the same treatment as in Example 9 except that ultrasonic irradiation was not performed.

(Comparative Example 3)
In Comparative Example 3, the same treatment as in Example 11 was performed except that ultrasonic irradiation was not performed, and a test paper after flotation was obtained.

(Comparative Example 4)
In Comparative Example 4, 0.2 mass% of compound (P2) was added instead of compound (P1) (for used paper), and the same treatment as in Example 11 was performed except that ultrasonic irradiation was not performed. A test paper was obtained.

(Comparative Example 5)
In Comparative Example 5, ultrasonic irradiation was performed for 2.5 minutes in 5 minutes of the flotation process (ultrasonic wave U6 as shown in FIG. 1). Except for ultrasonic irradiation during the flotation process, the same treatment as in Comparative Example 3 was performed to obtain a test paper after flotation.

(Comparative Example 6)
In Comparative Example 6, ultrasonic irradiation was performed for 2.5 minutes in the flotation process for 5 minutes (ultrasonic wave U6). Except for ultrasonic irradiation during the flotation process, the same treatment as in Comparative Example 4 was performed to obtain a test paper after flotation.

(Comparative Example 7)
In Comparative Example 7, ultrasonic irradiation was performed for 5 minutes instead of the flotation process (ultrasonic wave U7 as shown in FIG. 1). A test paper after flotation was obtained by performing the same treatment as in Comparative Example 3 except that the flotation process was not performed and ultrasonic irradiation was performed.

(Comparative Example 8)
In Comparative Example 8, the same treatment as in Example 33 was performed except that ultrasonic irradiation was not performed, and a test paper after flotation was obtained.

(Comparative Example 9)
In Comparative Example 9, the same treatment as in Example 41 was performed except that ultrasonic irradiation was not performed, and a test paper after flotation was obtained.

(Comparative Example 10)
In Comparative Example 10, a test paper after flotation was obtained by performing the same treatment as in Example 43 except that the ultrasonic irradiation was not performed.

(Comparative Example 11)
Comparative Example 11 is an example in which compound (P1) was added in an amount of 0.1% by mass (against waste paper) and compound (P3) was added in an amount of 0.1% by mass (against waste paper), and ultrasonic irradiation was not performed. The same treatment as in No. 43 was performed to obtain a test paper after flotation.

(Comparative Example 12)
In Comparative Example 12, ultrasonic irradiation was performed for 2.5 minutes in the 5 minutes of the flotation process (ultrasonic wave U6). Except for ultrasonic irradiation during the flotation process, the same treatment as in Comparative Example 10 was performed to obtain a test paper after flotation.

(Comparative Example 13)
In Comparative Example 13, ultrasonic irradiation was performed for 2.5 minutes in the flotation process for 5 minutes (ultrasonic wave U6). Except for ultrasonic irradiation during the flotation process, the same treatment as in Comparative Example 11 was performed to obtain a test paper after flotation.

(Comparative Example 14)
In Comparative Example 14, ultrasonic irradiation was performed for 5 minutes instead of the flotation process (ultrasonic wave U7). A test paper after flotation was obtained by performing the same treatment as in Comparative Example 10 except that the flotation process was not performed and ultrasonic irradiation was performed.

<Dart area ratio and dart average particle diameter after flotation>
About the evaluation at the time of using the UV curing type ink printing used paper, the dart area ratio and the dart average particle diameter after the flotation were measured and evaluated. The results are shown in Tables 4-7.

  A 5cm x 5cm portion (4 locations) of the test paper after the flotation was captured with a scanner at the same magnification, and this image was processed with analysis software (Image Pro Plus), and the dart area ratio after the flotation (%) And the dart average particle diameter (micrometer) was measured. The dirt area ratio (%) is a value indicating the percentage of the area occupied by the ink particles in the 5 cm × 5 cm portion of the test paper, and is an average value of four locations. The dirt average particle size (μm) is an average value of the average particle size of the ink particles in a 5 cm × 5 cm portion of the test paper, and shows an average value of four locations. A larger value for both the dart area ratio and the dart average particle diameter indicates that the ink peeling / miniaturization (hereinafter referred to as deinking property) is poorer. The dart area ratio after flotation is less than 0.6%. If the average particle size is less than 80 μm, the deinking property is excellent.

<Discussion>
As is clear from the results of the examples shown in Tables 4 to 6, the activity can be achieved by irradiating ultrasonic waves at any stage of the ultrasonic waves U1 to U5, or at a plurality of stages, or particularly at the ultrasonic wave U5 stage. Even with energy ray curable inks, fine ink particles are removed together with bubbles by flotation due to fine destruction of the ink particles, resulting in high-quality deinked pulp with excellent deinking properties. Obtained.

  Moreover, from the results of Examples 1 to 10, according to the method for producing deinked pulp according to the present embodiment, (I) NaOH as an alkaline agent is not added or the amount is reduced in the peeling / miniaturization step. However, it can be seen that a high quality deinked pulp having excellent deinking properties can be obtained.

  Further, from the results of Examples 19 to 32, the addition of the compound represented by the general formula (1) and the combined use of the compound (P2) can further improve the deinking property and provide a high quality deinking. Pulp was obtained.

  On the other hand, from the results of the comparative examples in Table 7, when ultrasonic irradiation is not performed, or ultrasonic irradiation is performed in the ultrasonic U7 stage instead of the ultrasonic wave U6 or the flotation process in the flotation process, Since the ink particles are not finely broken before the flotation step (S6), it is difficult for the ink particles to be removed together with bubbles by the flotation process. As a result, a low-quality deinked pulp having a poor deinking property was obtained.

<Whiteness after flotation, ERIC>
About the evaluation at the time of using used newspaper, whiteness and ERIC were measured with a colorimeter and evaluated. The results are shown in Tables 8 to 11. Note that ERIC is a numerical value obtained by measuring an absorption / diffusion coefficient at a wavelength of 950 nm, in which only ink is the main light absorption element, and indicates a residual ink density.

The test paper after the flotation was measured for whiteness and ERIC with a colorimeter (manufactured by COLOR TOUCH PC Technology). The measurement conditions of the colorimeter are as shown below.
[Colorimeter measurement conditions]
・ Light source: Measured with a C light source at a measurement angle of 2 ° ・ Lamp specifications: Pulsed xenon ・ Standard measurement diameter: φ30 mm
Note that the higher the whiteness value, the better the ink deinking property, and the ERIC, the higher the value, the poorer ink deinking property. If the whiteness after flotation is 53.3 or more and ERIC is 270 or less, the deinking property is excellent.

<Discussion>
As is apparent from the results of the examples shown in Tables 8 to 10, the ink is applied by irradiating ultrasonic waves at any stage of the ultrasonic waves U1 to U5, or at a plurality of stages, or particularly at the ultrasonic wave U5 stage. Even if it is an oxidation polymerization type ink particle that is easy to be refined but is difficult to peel off from the pulp fiber, the ink particle is easily removed from the pulp fiber, so that the ink particle is removed from the system together with the foam by the flotation treatment. A high-quality deinked pulp with excellent deinking properties was obtained.

  Further, from the results of Examples 33 to 42, according to the deinked pulp manufacturing method according to the present embodiment, (I) NaOH as an alkali agent is not added or the amount is reduced in the peeling / miniaturization step. However, it was found that a deinked pulp having excellent deinking properties and good quality can be obtained.

  In addition, from the results of Examples 51 to 64, by adding the compound represented by the general formula (1) instead of the compound (P1) or together with the compound (P1), the compound (P3) is further used in combination. As a result, a high-quality deinked pulp having excellent deinking properties was obtained.

  On the other hand, from the result of the comparative example in Table 11, when ultrasonic irradiation is not performed or ultrasonic irradiation is performed in the ultrasonic U7 stage instead of the ultrasonic wave U6 or the flotation process in the flotation process, Examples of Tables 8-10, because the ink particles are not peeled off from the pulp fibers before the flotation step (S6), making it difficult for the ink particles to be removed together with bubbles by the flotation treatment. As a result, a low-quality deinked pulp having inferior deinking properties was obtained.

(Other embodiments)
The above-described embodiment is an exemplification of the present invention, and the present invention is not limited to these examples, and these examples may be combined or partially replaced with known techniques, common techniques, and known techniques. Also, modified inventions easily conceived by those skilled in the art are included in the present invention.

  INDUSTRIAL APPLICABILITY According to the present invention, it is very useful because high-quality deinked pulp can be obtained by promoting the peeling and miniaturization of ink with respect to waste paper printed by various printing methods and inks.

1 Waste paper 2 Pulp fiber 3 Ink

Claims (6)

Including a disaggregation process, a separation / miniaturization process that separates and refines ink from waste paper,
A discharge step of discharging the ink that has been peeled / miniaturized in the peeling / miniaturization step,
In the delamination / miniaturization step, ultrasonic wave irradiation is performed, and a method for producing deinked pulp. The peeling / miniaturization step includes at least one of a high concentration treatment step, an aging step and a dilution step,
The method for producing deinked pulp according to claim 1, wherein the ultrasonic irradiation is performed in at least one of the high concentration treatment step, the aging step, and the dilution step. The peeling / miniaturization step includes the dilution step,
The method for producing deinked pulp according to claim 2, wherein the ultrasonic irradiation is performed in the dilution step. The nonionic surfactant and / or higher fatty acid or a salt thereof is added in at least one of the peeling / miniaturization step and the discharging step. The method for producing the deinked pulp according to the item. The deinking agent containing a compound represented by the following general formula (1) is added in at least one of the peeling / miniaturizing step and the discharging step. 2. A method for producing deinked pulp according to item 1.
(In General Formula (1), R ¹ , R ² , R ³ , and R ⁴ are each independently an alkyl group having 1 to 22 carbon atoms, a hydroxyalkyl group; an alkenyl group having 2 to 22 carbon atoms, and a hydroxyalkenyl group. A benzyl group; a glycidyl group; a group represented by the following general formula (2), wherein (A ¹ O) is an alkyleneoxy group having 2 to 4 carbon atoms, and Y is hydrogen or an acyl having 1 to 8 carbon atoms; N is an integer of 2 to 200 in terms of the number of repeating units of A ¹ O, and the number and carbon number of R ¹ , R ² , R ³ and R ⁴ having 1 to 4 carbon atoms and 2 carbon atoms. The sum of the number of hydroxyalkenyl groups of ˜4 and the number of n of A ¹ O is an integer of 0-200, and X ⁻ is a counter ion.)
The method for producing deinked pulp according to claim 1, wherein the ink is an active energy ray-curable ink and / or an oxidation polymerization type ink.