JP2001279588A - Method for manufacturing ink-removed pulp and paper containing the ink-removed pulp obtained by the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing ink-removed pulp from newspaper, magazines or the like, in which the paper produced by compounding the pulp and subjecting the compounded pulp to papermaking process is free from feathering and excellent in printing property when printed with an inkjet- type printer especially using an aqueous ink, and to provide paper. SOLUTION: This method for manufacturing ink-removed pulp comprises a defibring process for waste paper and a successive process using a surfactant- based ink-removing agent. In the method, a cationic polymer is added. Another objective paper is made by using the ink-removed pulp.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing deinked pulp from waste paper such as newspapers and magazines, and a paper having the deinked pulp blended therein and having an ink-jet recording suitability.

[0002]

2. Description of the Related Art Deinked pulp is used as a raw material for papermaking together with wood pulp from the viewpoint of resource saving and measures against municipal waste treatment, and is widely used in the fields of newspapers, magazines, copy paper and the like. Generally, the method for producing deinked pulp is to separate the ink and pulp by washing or flotation, etc., after a process of disintegrating waste paper, a deinking process such as kneading in the presence of a deinking agent and alkali, and the like. Blacking), followed by washing and bleaching as necessary. For example, waste paper on which newspapers, magazines, etc. have been printed is disintegrated with an alkaline chemical or the like using a disintegrator such as pulper, and further, an alkaline chemical, hydrogen peroxide or a surfactant is added, and alkali soaking (alkaline immersion) is performed. The ink and the pulp are peeled off by swelling the pulp fibers using a mechanical stirring force, and then the ink is separated from the pulp by washing or flotation to produce deinked pulp.

In Japan, the recovery rate of waste paper as a raw material for papermaking is about 50%, but the use of waste paper pulp is increasing not only for ordinary paper but also for recording paper such as copy paper with the aim of further using recycled paper. In the situation. In recent years, personal computers have spread not only in offices but also in homes, and accordingly, ink jet printers have been remarkably spread. As the output paper of the inkjet printer, there is a special coated paper, but a copy paper is also used. However, when ink jet recording is performed on copy paper containing deinked pulp, characters are difficult to read due to feathering, and when variable data such as barcodes are recorded, barcodes and the like are difficult to read. there were. In order to solve this, when making a paper using a pulp slurry containing deinked pulp, a large amount of inner lacquer is mixed, or a surface sizing agent is added to the surface of the paper using a size press device or the like. Has been performed, but a satisfactory product has not yet been obtained.

[0004]

In view of the above circumstances, an object of the present invention is to provide a paper made by mixing deinked pulp, especially when the paper is recorded by an ink jet method using an aqueous ink. An object of the present invention is to provide a method for producing a deinked pulp capable of preventing or significantly improving the occurrence of whisker-like bleeding of ink and a paper containing the pulp.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found the following method which has never been considered before. That is, in a method for producing a deinked pulp comprising at least a waste paper disintegration step and a plurality of steps having a deinking step using a surfactant-based deinking agent, the cationic polymer is used in any of the plurality of steps. The present invention has been accomplished by a method for producing deinked pulp which is added and deinked in the presence of a cationic polymer. The paper containing the deinked pulp thus obtained can be a paper having no feathering (i.e., whisker-like bleeding of the ink) or a significantly improved paper when recorded using an ink jet method, particularly an aqueous ink. did it. The reason why the above object is achieved by the present invention is not necessarily clear, but is considered as follows.

The production of deinked pulp comprises the steps of defibration, deinking, washing and bleaching, and is performed by combining these steps according to the type of waste paper and the purpose of use of the deinked pulp. When disintegrating waste paper with a pulper, an alkaline chemical is added to increase the water absorption of the waste paper to make it easier to loosen fibers, and the fibers are rubbed by mechanical stirring force to separate the waste paper into individual fibers, Separate and peel ink from fiber. Further, a surfactant-based deinking agent is added together with an alkaline chemical to promote separation and peeling of the ink from the fiber, and subsequently, the ink separated from the fiber by a washing method or a flotation method is discharged out of the system. Further, if necessary, washing and bleaching are performed to obtain a deinked pulp having a desired whiteness. In the deinking pulp produced by this method, the deinking agent mainly composed of a surfactant is firmly bonded to the fiber surface or enters the inside of the fiber,
Since the surfactant cannot be completely washed away by the ordinary cleaning degree in the cleaning process of deinked pulp, such deinked pulp is blended with virgin pulp and recorded on paper made with an ink-jet method using water-based ink. In this case, it is considered that feathering occurs because ink bleeding partially becomes extremely large.

In the present invention, when producing deinked pulp,
The reason why the paper without the feathering can be obtained by treating the pulp with the cationic polymer is considered to be due to the following reason.
The dye of the ink used in the ink jet system has an anionic group such as a sulfonic acid group and a carboxyl group. By treating waste paper pulp with a cationic polymer, a cationic group is present on the surface or inside of the pulp fiber. For this reason, it is considered that an ionic bond and a coordination bond occur between the cationic polymer and the dye in the ink to form a complex or a complex salt, and the dye becomes water-insoluble, and the dye is instantaneously separated and fixed from the ink solution layer. Can be

The paper containing such deinked pulp can be used as it is, or can be used as a base paper for coating. In particular, when used as an electrophotographic transfer paper, it is possible to preferably respond to the demand for adding a barcode or the like to the electrophotographic transfer paper, which has been increasing in recent years, by aqueous inkjet recording.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the treatment with a cationic polymer is preferably carried out before adding a surfactant-based deinking agent, and more preferably after adding an alkaline chemical. Good before adding black ink. It is preferable that the amount of the alkaline chemical added is as small as possible.

The cationic polymer used in the present invention includes a dicyandiamide / alkylamine polymer, a dicyandiamide / formalin polymer, a polyethyleneimine derivative, an alkylamine / epichlorohydrin polymer, and an ammonia / epichlorohydrin polymer. And commercially available chemicals such as polymethacrylic acid-based quaternary ammonium salt derivatives and dimethyldiallylammonium chloride-based polymer. Among them, alkylamine / epichlorohydrin-based polymer compounds and dimethyldiallylammonium chloride-based polymer are particularly preferable. It is preferable to use it even if it is used in a smaller amount than other cationic polymers because the effect is obtained.

In the present invention, the amount of the cationic polymer to be added is preferably in the range of 0.2 to 5.0% by weight, more preferably in the range of 1.0 to 2.5% by weight, based on the absolute dry weight of waste paper pulp. preferable. When the amount of the cationic polymer is less than 0.2% by weight based on the absolute dry weight of the waste paper pulp,
When a paper made by mixing the pulp and the virgin chemical pulp is recorded by an ink jet printer or the like using an aqueous ink, feathering increases and the recording quality tends to be remarkably inferior. On the other hand, when the amount of the cationic polymer added is more than 5.0% by weight based on the absolute dry weight of the waste paper pulp, the pulp fibers may be flocced due to an excessively high cation concentration. Also, the effect on feathering does not change significantly, which is not preferable from the viewpoint of cost.

The surfactant-based deinking agent of the present invention includes:
Anionic surfactants such as carboxylic acid type, sulfate ester type, sulfonic acid type and phosphate ester type, nonionic surfactants such as ether type, ester type and fatty acid alkylol amide type, amino acid type and betaine type etc. It can be used alone or in combination among surfactants and the like.

As the alkaline chemical of the present invention, known chemicals such as caustic soda, soda ash, sodium bicarbonate, sodium silicate and the like are used, but caustic soda is preferably used in consideration of handling and cost. In addition, in the case of using an alkaline chemical in the defibration step, the amount of addition is preferably as small as possible because the effect of the sizing agent used in combination may be reduced, and is preferably 1.0% by weight or less based on waste paper pulp. .

The paper of the present invention can be obtained by using the deinked pulp produced by the present invention alone or in combination with a conventionally used pulp. Hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood bleached sulphite pulp (LBSP), softwood bleached sulphite pulp (NBS)
Wood pulp such as chemical pulp such as P) and mechanical pulp such as groundwood pulp (GP) and thermomechanical pulp (TMP) can be used. In addition, cotton pulp, hemp, bagasse, kenaf, espart, camellia, goose, etc. Non-wood pulp can also be used.

[0015] The paper of the present invention may optionally contain fillers and other chemicals such as sizing agents. The filler to be internally added is not particularly limited, and can be appropriately selected from known fillers and used. Such fillers include, for example, talc, kaolin, illite,
Clay, heavy or light calcium carbonate, titanium dioxide and the like can be mentioned. The filler is usually used in an amount of 3 to 20% by weight as a filler in paper. The internal sizing agent used for paper is not particularly limited, and known internal sizing agents used for printing paper, copy paper, ink jet recording paper, etc., for example, ASA-based, AKD-based, rosin-based, styrene-based , Acrylic, styrene / acrylic,
One or more kinds can be appropriately selected from olefin sizing agents and the like. Preferred internal sizing agents include, for example, hydrophobic modified rosin emulsion sizing agents. Usually, the amount of the inner lacquer used is in the range of 0.1 to 0.7% based on the absolute dry weight of the pulp. Further, if necessary, an antifoaming agent, a pH adjuster, a dye or a color pigment for adjusting a hue, a fluorescent dye for improving visual whiteness, and the like can be further added.

Further, the paper of the present invention can be coated with a sizing solution containing a known sizing agent, binder and the like, if necessary. As means for coating, known coating devices such as various blade coaters, roll coaters, air knife coaters, bar coaters, curtain coaters, gravure coaters, gate roll coaters, etc. can be used, and can be provided on one or both surfaces. Although it is possible, from the viewpoint of operability and cost, it is preferable to use a size press coating method capable of coating both surfaces simultaneously on-machine. Further, as the surface finish, various calenders such as a machine calender, a soft calender, and a super calender can be used alone or in combination.

The paper obtained by making the paper using the deinked pulp produced according to the present invention is particularly effective for ink-jet paper, and is useful for recording paper such as electrophotographic transfer paper and thermal transfer paper. It can also be used for printing paper.

[0018]

EXAMPLES The method for producing deinked pulp of the present invention and the specific constitution of the recording paper using the deinked pulp will be described below with reference to examples and comparative examples. Is not limited by this. In the examples, “%” is all “% by weight”, and “parts” are all “parts by weight”.
Is shown. Example 1 A newspaper wastepaper was put into a test pulper with water so as to have a pulp concentration of 5%, and NaOHl. After adding 0% and disintegrating for 5 minutes, 2.0% based on the absolute dry weight of the pulp was added with an alkyl-ammonia-epichlorohydrin polycondensate (PF-700, manufactured by Showa Polymer Co., Ltd.) as a cationic polymer, and added for 30 minutes. The mixture was stirred and dehydrated to a concentration of 18%. Add water and add 2%
And a surfactant-based deinking agent (DI-767,
1.0% of the pulp was added to the pulp, and the mixture was subjected to a flotation treatment using a test flotator for 6 minutes and dehydrated to a concentration of 18%. Further, water was added to dilute to 2%, NaOH 2.0%, NaSiO ₃ 4.0.
% And H ₂ O ₂ 3.0%, and then mixed with a steam mixer, followed by bleaching at a temperature of 70 ° C. for 3 hours. Thereafter, washing and dewatering were performed to obtain an 18% deinked pulp.

The deinked pulp (50 parts) obtained by the above-mentioned production method and the hardwood bleached kraft pulp (L-BK) having a beating degree of 450 ml are used.
P) 7 parts of talc, 1.5 parts of sulfuric acid band, 0.4 part of sizing agent, 0.0 part of retention aid in 50 parts of pulp slurry
Two parts were added and hand-made. After drying, using a two-roll size press, the coating amount of the coating liquid 1 on both sides is 4 g in solid content.
/ ^{M 2} and composed as applied to obtain a paper having a basis weight of 74 g / ^{m 2.} (Coating liquid 1) Water-soluble polymer: oxidized starch MS # 3600 (manufactured by Nippon Shokuhin Kako Co., Ltd.) 100 parts Surface sizing agent: Polymalon 360 (manufactured by Arakawa Chemical Industry Co., Ltd.) 2 parts Antifoaming agent: Nopco 8034L ( 0.1 part [manufactured by San Nopco Co., Ltd.] [Example 2] A basis weight of 74 g / m ^{2 was} obtained in the same manner as in Example 1 except that the addition amount of the cationic polymer was 0.2%.
I got a piece of paper. Example 3 A basis weight of 74 g / m ^{2 was} obtained in the same manner as in Example 1 except that the addition amount of the cationic polymer was 5.0%.
I got a piece of paper. Example 4 The basis weight was changed in the same manner as in Example 1 except that the cationic polymer was changed to a dimethyldiallylammonium chloride polymer (PAS-H-10L, manufactured by Nitto Boseki Co., Ltd.) and 2.0% was added. 74 g / ² paper was obtained. [Example 5] The cationic polymer was changed to polyethylene imine (Epomin PP-061, manufactured by Nippon Shokubai Co., Ltd.).
A paper having a basis weight of 74 g / m ² was obtained in the same manner as in Example 1 except that 2.0% was added. Example 6 A paper having a basis weight of 74 g / m ² was obtained in the same manner as in Example 1 except that the cationic polymer was changed to polyethyleneimine and 5.0% was added. [Example 7] The amount of cationic polymer added was 10.0%
Except that the basis weight was 74 g / m2 in the same manner as in Example 1.
² paper was obtained. [Example 8] Water was added to a test pulper so that the pulp concentration was 5%. NaOHl. After adding 0% and disintegrating for 5 minutes, the concentration is 18%
Dehydrated so as to become. Add water and dilute to 2%
Further, a surfactant-based deinking agent (DI-767, manufactured by Kao Corporation) is added to the pulp at 1.0%, and the pulp is subjected to a flotation treatment using a test flotator for 6 minutes. 2.0% based on the absolute dry weight of the pulp was added, and the mixture was stirred for 30 minutes and dehydrated to a concentration of 18%. Further dilute to 2% by adding water, NaOH 2.0
%, 4.0% of NaSiO _{3, and} 3.0% of H ₂ O _{2, and then} mixed with a steam mixer, followed by bleaching at a temperature of 70 ° C. for 3 hours. Thereafter, washing and dewatering were performed to obtain an 18% deinked pulp.

A paper having a basis weight of 74 g / m ² was obtained in the same manner as in Example 1 except that deinked pulp was obtained by the above manufacturing method. Comparative Example 1 A basis weight of 74 g / g was obtained in the same manner as in Example 1 except that the cationic polymer was not added (the amount added was 0%).
to obtain a paper m ^2. [Comparative Example 2] Same as Example 1 except that no cationic polymer was added when producing the deinked pulp, and 40 parts of an alkylamine / ammonia / epichlorohydrin polycondensate was added to the coating liquid 1 as the cationic polymer. 7 basis weight by method
4 g / m ² of paper were obtained.

The ink jet recording test of the recording papers obtained in Examples 1 and 2 was performed by the following method.

The results are summarized in Table 1.

[0023]

[Table 1] From Table 1, it can be seen that Examples 1 to 7 of the present invention have significantly improved feathering and good ink drying properties, whereas Comparative Examples 1 and 2 have significantly poor feathering. (1) Inkjet recording test The recording test was performed using an inkjet printer (BJC-420).
J: trade name, manufactured by Canon Inc.), and a predetermined pattern was recorded and evaluated according to the following criteria. a, Feathering (whisker-like bleeding of ink) Whisker-like bleeding of the ink was visually evaluated. ○ No whisker-like bleeding, △ Slight whisker-like bleeding, × Many whisker-like bleeding, b, ink drying property Immediately after recording, the image area was rubbed with a finger, and the degree of dirt was visually evaluated. ○ No dirt △ Slightly dirt × Extremely dirt

[0024]

By using the deinked pulp obtained by the method for producing deinked pulp according to the present invention, feathering does not occur when ink-jet recording is performed, and high-quality pulp which cannot be achieved by the conventional method can be obtained. Paper having recordability was obtained.

Claims (4)

[Claims] 1. A method for producing a deinked pulp comprising a plurality of steps including at least a waste paper disintegration step and a deinking step using a surfactant-based deinking agent, wherein at least one of the plurality of steps is cationic. Method for producing deinked pulp characterized by adding a polymer 2. The method according to claim 1, wherein the cationic polymer is an alkylamine.
The method for producing a deinked pulp according to claim 1, wherein the method is an epichlorohydrin-based polymer compound or a dimethyldiallylammonium chloride-based polymer. 3. The method for producing deinked pulp according to claim 1, wherein the amount of the cationic polymer added is from 0.2 to 5.0% by weight based on waste paper pulp. 4. A paper containing deinked pulp produced by the production method according to claim 1.