JPH10219574A - Method for removing ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain pulp good in whiteness and an area-ratio of residual ink in good yield by putting disaggregated pulp obtained from waste paper and stripped ink into a liquid capable of separating into a phase having affinity to the ink and a phase having affinity to the pulp by standing. SOLUTION: This method for removing ink is to put disaggregated pulp obtained from waste paper as a raw material and stripped ink into immiscible liquids in standing, i.e., one to be a phase having affinity to the ink and the other to be a phase having affinity to the pulp, distribute respectively into the phase having affinity to the pulp and the phase having affinity to the ink at 5-80 deg.C and separate the disaggregated pulp and the stripped ink. Removal of the ink from newspapers, handbills, magazines, OA waste paper, etc., is effectively carried out and the ink-removed pump having high quality is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to newspapers, flyers,
The present invention relates to a deinking method for efficiently deinking and reusing waste paper materials such as magazines and OA waste paper. More specifically,
The present invention relates to a deinking method for obtaining a high-quality deinked pulp having a high pulp yield and a higher whiteness in a regeneration process.

[0002]

2. Description of the Related Art Waste paper is deinked to remove and remove ink from the waste paper.
It is recycled by obtaining recycled pulp and producing recycled paper therefrom. Conventionally, the deinking method, as its process,
(1) Used paper pulping (disintegration) step, (2) aging and bleaching step, (3) flotation step, and (4) washing step. Disintegration of the ink from the pulp is performed physically, chemically or biochemically using a deinking agent. The ink is removed by a flotation method and / or a washing method described below.

The flotation method is a method of removing ink by blowing air bubbles, adsorbing the separated floating ink to the air bubbles, and discharging the air bubbles having the ink adsorbed out of the system.
It is currently commonly used in the pulp and paper industry. In the flotation method, high whiteness can be obtained if the amount of bubbles is large, but the amount of pulp brought out by bubbles also increases, and the pulp yield decreases, making it difficult to achieve both.

[0004] On the other hand, the washing method is a method of washing away the separated floating ink using a large amount of water. However, in order to improve the whiteness, the amount of water used is enormous. The fine pulp that flows out along with the ink into the water lowers the pulp yield and causes a problem in the treatment of drainage water. Further, the ink to be removed stays in the pulp fiber depending on the filterability of the pulp, and the quality is not improved. To avoid this problem, a larger amount of water is required.

[0005] As described above, in the conventional flotation method and cleaning method, it was not possible to easily obtain excellent results in both pulp performance such as whiteness and remaining ink area ratio and yield.

[0006]

[Means for Solving the Problems] From the above situation,
The present inventors have conducted intensive studies on a deinking method that can achieve excellent pulp performance and yield. It has been found that the ink and the pulp can be easily separated by distributing the disintegrated pulp to each other, and the above object can be achieved, and the present invention has been completed.

That is, the present invention uses a liquid which becomes an ink-philic phase and a liquid which becomes a parent-pulp phase which are not mixed with each other in a stationary state at least at a temperature condition of 5 to 80 ° C. A deinking method characterized by comprising a step of separating a release ink and a disintegrated pulp by distributing a disintegrated pulp and a release ink obtained from waste paper to a parent pulp phase and a parent ink phase, respectively. Things.

[0008] While the conventional method for separating the release ink and the disintegrated pulp is based on the phenomenon of collision with air bubbles and adsorption, the deinking method of the present invention differs in the affinity of ink and pulp for various liquids. It is a thing using.

In the present invention, "not mixed with each other" means, for example, that a mixture is temporarily mixed in a stirring state like water and oil, but separates into two layers when left standing. Such layer separation occurs when there is a significant difference in the polarity of the liquid.

[0010] The "philic ink phase" is a phase composed of a liquid having a high affinity for the ink particles and capable of distributing the ink particles more easily. On the other hand, the “parent pulp phase” is a phase composed of a liquid having a high affinity for pulp and capable of distributing pulp more easily.

The liquid having a good affinity for the ink is one or two selected from oils and fats, fatty acids, amines, ethers, esters, aromatic hydrocarbons, saturated or unsaturated hydrocarbons, halogenated hydrocarbons and mineral oils. The above liquids are mentioned. Examples of oils and fats include animal and vegetable oils such as olive oil, linseed oil, palm oil, rapeseed oil, soybean oil, and fish oil. In addition, examples of the fatty acid include oleic acid and linoleic acid. As the amine, octylamine, laurylamine, dimethyloctylamine and the like are preferable. As aromatic hydrocarbons, benzene, toluene,
Xylene and the like can be mentioned. Examples of the ether include diethyl ether and tetrahydrofuran. Examples of the ester include ethyl acetate and methyl oleate. Examples of the saturated hydrocarbon include hexane, heptane, cyclohexane, petroleum ether and the like. Examples of the unsaturated hydrocarbon include hexene, heptene, cyclohexene and the like. Examples of the halogenated hydrocarbon include chloroform, carbon dichloride, carbon tetrachloride, ethylene chloride and the like.

It is preferable to use a liquid having a specific gravity of 1 or less as a liquid to be an ink-philic phase. This is because the release ink usually contains only a few percent of the disintegrated pulp, and the pulp has a relatively high specific gravity. This is because it is advantageous in the ink separation step.

The liquid having a good affinity for pulp may be one or two selected from water, alcohol and ketone.
More than one kind of liquid is mentioned, and a liquid mainly composed of water or an aqueous solution containing a water-soluble solvent is preferable. Examples of the water-soluble solvent include alcohols and ketones. Examples of the alcohol include lower monoalcohols such as methanol and ethanol, and polyols such as glycerin and polyethylene glycol. In addition, examples of the ketone include acetone and the like.

The selection of these liquids must be made in consideration of the polarity of the ink and the pulp, etc., in such a manner that they have good affinity and distribution with each other and that the phases do not mix with each other. Are not limited to those exemplified above. Even if you have enough ink and pulp distribution capacity,
In the case where they are dissolved into each other to form one liquid, the ink and the pulp cannot be easily separated.

[0015]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a liquid to be an ink-philic phase and a liquid to be a pulp-philic phase are subjected to at least one of the steps prior to the step of discharging the release ink outside the deinking system. Should exist. That is, as described above, the deinking method generally includes (1)
The method includes a pulping (disintegration) step of waste paper, (2) an aging and bleaching step, (3) a flotation step, and (4) a washing step. This is characterized in that the release ink and the defibrated pulp are separated, and if this object is achieved, these liquids may be added in any of the above steps (1) to (4). For example, a liquid (usually,
To the slurry of (water), a liquid to be an ink-philic phase may be added together with another liquid to be a parent pulp phase, if necessary [addition in step (3)]. The de-inking step may be performed by allowing the liquid to be the phase and the liquid to be the pulp parent phase to exist in the de-inking system (addition in step (1)).

Accordingly, the deinking method of the present invention comprises the steps of: (a) mixing a system containing a liquid to be an ink-philic phase, a liquid to be a pulp-philic phase, a disintegrated pulp obtained from raw waste paper, and a release ink; 2. The deinking method according to claim 1, wherein the release ink is distributed to the parent ink phase and the disintegrated pulp is distributed to the parent pulp phase, and after standing, the release ink and the disintegrated pulp are separated. A pulverized pulp and a release ink are obtained from a system (A) containing a liquid to be an ink phase and a liquid to be a parent pulp phase, and the obtained pulverized pulp and release ink are respectively used as the parent pulp phase and the parent ink in the system (A). Includes a deinking method of distributing to the ink phase. Specifically, (c) In a deinking method including a pulp (disintegration) step of waste paper, a liquid to be an ink phase and a parent pulp phase before the pulp step are included. Liquid and deinking system (D) In the deinking method including the ripening step, the liquid to be the ink-philic phase and the liquid to be the pulp-philic phase are present in the deinking system prior to the aging step. In the black ink method, a liquid to be an ink-affinous phase and a liquid to be a parent pulp phase are present in the deinking system before the bleaching step. (F) In the deinking method including the flotation step, (G) In a deinking method including a washing step, a liquid to be an ink-affinous phase and a liquid to be a pulp-free phase are present before the washing step. And a method of causing the liquid to be present in the deinking system.

For example, in the method (a), a system containing a disintegrated pulp and a release ink is prepared from raw material waste paper in accordance with a known deinking method, and a system containing the disintegrated pulp and a release ink is prepared. By mixing a system consisting of a liquid that is a phase and a system that contains a liquid that is an ink-philic phase, a liquid that is a parent pulp phase, and a disintegrating pulp obtained from raw waste paper and a release ink, The ink is distributed to the parent ink phase and the defibrated pulp is distributed to the parent pulp phase. After standing, the release ink and the defibrated pulp are separated. On the other hand, in the method of (b), a liquid to be an ink-philic phase and a liquid to be a pulp-philic phase are charged in a pulp (disintegration) step of a raw material waste paper and the like, and a deinking step is performed according to a known deinking method. The disintegrated pulp and the release ink obtained by stirring and mixing the system are respectively distributed to the parent pulp phase and the parent ink phase in the system. In any of the methods, a part or all of the liquid serving as the parent pulp phase can be used as an aqueous medium used for obtaining disintegrated pulp and release ink from raw waste paper. Further, in any method, the timing of adding the liquid to be the pulp-philic phase and the liquid to be the ink-philic phase may be different. In particular, it is advantageous to use the aqueous medium (usually water) used in the deinking system in which all of the liquid to be the parent pulp phase does not need to separately add a liquid to be the parent pulp phase. That is, for example, in the above-mentioned method (a), all of the liquid to be the parent pulp phase is converted into water or a mixture of water and a suitable hydrophilic solvent used for obtaining a disintegrated pulp and a release ink from raw waste paper, Performing a normal deinking process, then adding the liquid to be the parent ink phase into the system and then mixing the system to distribute the release ink to the parent ink phase and the disintegrated pulp to the parent pulp phase. Can be.

In the present invention, the ratio of the liquid (a ₁ ) to be the parent ink phase and the liquid (a ₂ ) to be the parent pulp phase is not limited, but preferably (a ₁ ) :( a ₂ ) = 1: 99-9
5: 5 (volume ratio), more preferably 5:95 to 70: 3
0 (volume ratio).

In the present invention, the liquid (a ₁ ) to be an ink-philic phase
And also the parent pulp phase liquid (a ₂₎ as added in any step, the parent ink phase and a liquid (a ₁₎ and a liquid (a ₂₎ as a parent pulp phase, obtained from the raw material waste paper Mixing of the disintegrated pulp and the system containing the release ink is performed, thereby distributing the release ink to the parent ink phase and disintegrating pulp to the parent pulp phase. After mixing, the mixture is allowed to stand for a while, and the parent ink phase containing the release ink and the parent pulp phase containing the disintegrated pulp separate into two layers. Next, the separated ink and the disintegrated pulp can be separated by collecting each separated phase. Specifically, the liquid (a ₁ ) which becomes the ink-philic phase and the liquid (a ₂ ) which becomes the pulp-philic phase, and the disintegrated pulp and the release ink obtained from the raw material waste paper are mechanically or by blowing air bubbles. After mixing the system [system (X)] containing
Separation can be performed by allowing the system (X) to stand in a separation funnel.
Ink and pulp may be distributed and separated into the parent ink phase and the parent pulp phase, respectively, and industrially, a method of stirring and mixing the system (X) in a tank, followed by separation, and a method of separating the system (X) in a flotator X) is present, air bubbles are blown, and the ink and the pulp are distributed to the parent ink phase and the parent pulp phase for separation. Among them, a method of performing mixing that allows industrial use of existing equipment by blowing air bubbles is more preferable. Regarding the mixing time of the system (X), the time during which the mixing is sufficiently performed may be appropriately determined according to the scale, and is usually 1 to 60 minutes.

In the practice of the present invention, the ink and pulp in the system containing the disintegrated pulp and the release ink before separation are more uniformly dispersed, so that the separation efficiency is better. Liquid that becomes the system and ink-philic phase
It is preferable that the mixed system of (a ₁ ) and the liquid (a ₂ ) which becomes the pulp-parent phase contains a surfactant. The surfactant may be added at the time of separation of the ink and the pulp, or may be added before this step. The deinking agent (surfactant) used for the ink stripping may be used as it is with the disintegrated pulp and the release ink. It may be present in the containing system. As the surfactant, any of a nonionic surfactant, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant can be used, and one type of surfactant in these categories can be used. And two or more surfactants can be used in combination.
Preferred are nonionic surfactants.

Further, in the present invention, an inorganic salt and a polymer compound can be added for adjusting the polarity and specific gravity of the liquid (a ₁ ) and the liquid (a ₂ ). As the inorganic salt, sodium chloride, potassium chloride, calcium chloride, sodium sulfate, sodium hydrogen sulfate and the like are preferable. Examples of the polymer compound include polyacrylamide and sucrose. For the purpose of adjusting the polarity and the specific gravity, the blending amount, the molecular weight, and the like are not limited, and may be appropriately determined according to the purpose.

[0022]

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

In the following examples, EO is ethylene oxide, PO is propylene oxide, and the number of moles is the average number of moles added.

Comparative Example 1 Raw material recovered in the city (newspaper / flyer = 70/3)
After shredding 0) to 5 cm x 4 cm, a certain amount was put into a tabletop disintegrator, in which hot water and sodium hydroxide 1% by weight (based on raw material), sodium silicate 3% by weight (based on raw material), 30% peroxide Hydrogen water 3% by weight (based on raw material), stearyl alcohol EO 15 mol PO 15 mol block adduct as deinking agent
3% by weight (based on the raw material) was added, and the pulp concentration was 5% by weight.
Disintegrated at 10 ° C for 10 minutes. The obtained pulp slurry is mixed with 40
After ripening at 60 ° C. for 60 minutes, warm water was added to dilute the pulp concentration to 1%, followed by a flotation treatment at 40 ° C. for 10 minutes. After the flotation treatment, a pulp sheet was prepared using a tapping machine, and 3.5 kgf / cm ^{2 was} pressurized, followed by drying with ventilation, and measurement of pulp yield, whiteness, and residual ink area ratio were performed. Table 1 shows the results.

Comparative Example 2 Raw material recovered from the market (newspaper / flyer = 70/3)
After shredding 0) to 5 cm x 4 cm, a certain amount was put into a tabletop disintegrator, in which hot water and sodium hydroxide 1% by weight (based on raw material), sodium silicate 3% by weight (based on raw material), 30% peroxide Hydrogen water 3% by weight (based on raw materials), stearyl alcohol EO 15 mol PO 10 mol random adduct as a deinking agent
2% by weight (relative to the raw material), pulp concentration 5% by weight, 40%
Disintegrated at 10 ° C for 10 minutes. The obtained pulp slurry is mixed with 40
After aging at 60 ° C. for 60 minutes, washing was performed by repeating twice the operation of adding warm water to dilute the pulp concentration to 1%, sieving the mixture to 6% with a sieve, and further diluting the pulp concentration to 1%. . After the washing treatment, a pulp sheet was prepared with a tapping machine, pressurized at 5 kgf / cm ² , dried with ventilation, and measured for pulp yield, whiteness and remaining ink area ratio.

Example 1 (Test Nos. 1 to 8) Raw material recovered from the city (newspaper / flyer = 70/3)
After shredding 0) to 5 cm x 4 cm, a certain amount was put into a tabletop disintegrator, in which hot water and sodium hydroxide 1% by weight (based on raw material), sodium silicate 3% by weight (based on raw material), 30% peroxide Hydrogen water 3% by weight (based on raw material), stearyl alcohol EO 15 mol PO 15 mol block adduct as deinking agent
3% by weight (based on the raw material) was added, and the pulp concentration was 5% by weight.
Disintegrated at 10 ° C for 10 minutes. The obtained pulp slurry is mixed with 40
After ripening at 60 ° C. for 60 minutes, warm water was added to dilute the pulp concentration to 1% to obtain a pulp-friendly liquid composition shown in Table 1, and the ink-friendly liquid was added to the 1% pulp slurry.
It was added in an amount of 0% by weight and subjected to a flotation treatment at room temperature for 10 minutes. After flotation process, the aqueous layer is dispersed in the pulp were separated, and the pulp sheet produced in Tappimashin, after pressure 3.5 kgf / cm ² pressure, and air dried, pulp yield, whiteness and residual ink area The rate was measured. In addition, in the example using two kinds of ink-philic liquids or pulp-philic liquids, the volume ratio of both is also shown in the table (the same applies to the following examples).

[0027]

[Table 1]

In the above Examples and Comparative Examples, the whiteness is measured by a spectral whiteness meter, and a difference of 1 in the numerical value is sufficiently recognized visually and recognized as a significant difference. In addition, the remaining ink area ratio is calculated using an image analyzer (magnification;
100), a decrease of 0.1% can be visually recognized as a sufficiently improved quality of the pulp sheet (the same applies to the following examples).

Example 2 (Test Nos. 9 to 16) In Example 1, 0.3% by weight of stearyl ether sulfate (based on raw material) was used as a deinking agent, and the composition was adjusted to the pulp-philic liquid composition shown in Table 2. Then, an ink-philic liquid was added, and the mixture was stirred at 100 rpm for 10 minutes at room temperature. After the treatment, the aqueous layer in which the pulp was dispersed was separated. Otherwise, a pulp sheet was prepared in the same manner as in Example 1, and the same evaluation was performed. Table 2 shows the results.

Example 3 (Test Nos. 17 to 19) In Example 1, cetyltrimethylammonium chloride (0.3% by weight (based on raw material)) was used as a deinking agent, and the composition was adjusted to a pulp-philic liquid composition shown in Table 2. Thereafter, the ink-philic liquid was added, and the mixture was stirred at 100 rpm for 10 minutes at room temperature. After the treatment, the aqueous layer in which the pulp was dispersed was separated. Otherwise, a pulp sheet was prepared in the same manner as in Example 1, and the same evaluation was performed. Table 2 shows the results.

[0031]

[Table 2]

Example 4 In the same manner as in Example 1 except that the timing of adding the ink-philic liquid and the adjustment (addition of methanol) of the pulp-philic liquid in Test Nos. 1 and 7 in Example 1 were before the defibration step. To produce a pulp sheet, and the same evaluation was performed. Table 3 shows the results.

[0033]

[Table 3]

Claims (6)

[Claims] 1. A liquid obtained from raw waste paper using a liquid that is an ink-philic phase and a liquid that is a pulp-philic phase that are immiscible with each other in a stationary state under a temperature condition of at least 5 to 80 ° C. A deinking method comprising a step of separating the release ink and the disintegrated pulp by distributing the disintegrated pulp and the release ink to the parent pulp phase and the parent ink phase, respectively. 2. A mixture containing a liquid to be an ink-philic phase, a liquid to be a pulp-philic phase, a disintegrated pulp obtained from raw waste paper, and a release ink, and distributing the release ink to the parent ink phase; The deinking method according to claim 1, wherein the defibrated pulp is distributed to the parent pulp phase, and after leaving to stand, the release ink and the defibrated pulp are separated. 3. The deinking method according to claim 1, wherein the deinking method includes a flotation step, and a liquid serving as an ink-affinitive phase and a liquid serving as a parent pulp phase are present in the deinking system before the flotation step. Ink method. 4. The method according to claim 1, wherein distribution of the disintegrated pulp to the parent pulp phase and distribution of the release ink to the parent ink phase are performed by stirring and mixing of a deinking system by blowing air bubbles. Deinking method. 5. The liquid which becomes an ink-philic phase is one or more selected from oils and fats, fatty acids, amines, ethers, aromatic hydrocarbons, saturated or unsaturated hydrocarbons, halogenated hydrocarbons and mineral oils. The deinking method according to any one of claims 1 to 4, wherein the liquid is a liquid. 6. The deinking method according to claim 1, wherein the liquid serving as the pulp-philic phase is one or more liquids selected from water, alcohol and ketone.