JP4855995B2 - Deinking agent for used paper recycling - Google Patents

Description

  The present invention relates to a deinking agent for recycling used paper. In more detail, when deinking a newspaper, magazine, OA wastepaper, etc., using the flotation method, which is currently the mainstream, it is used to recycle wastepaper used to obtain deinked pulp with high whiteness and very little residual ink. It relates to ink.

  Recycling as a papermaking raw material for deinked pulp (hereinafter referred to as “DIP”) produced by deinking from used printed paper such as newspapers, magazines, and OA used paper has been practiced for a long time. From the viewpoint of effective use and environmental protection, the recycling of waste paper is becoming more and more important and the use of recycled pulp is also expanding. With the further expansion of the usage rate of used paper, the use of low-grade used paper, which has been used so far, such as magazine used paper and office used paper, has been progressing. In addition, newspaper waste paper, which is the mainstream of raw paper, has been shifting from acidic papermaking to neutral papermaking, and the properties of the raw paper itself are changing greatly.

  Neutral paper making tends to decrease the ink peelability due to the influence of chemicals used and the like, and the amount of unpeeled ink in the DIP tends to increase compared to the acid paper making newsprint. In order to reduce the unpeeled ink, it is necessary to increase the mechanical stress. However, because waste paper is mixed and used without being separated due to good or bad ink releasability, waste paper used in acid papers mixed with waste paper raw materials has excessive ink peeling and further refines free ink. proceed. As the ink becomes finer, the fine ink released in the DIP manufacturing process accumulates, and the DIP quality deteriorates. Further, the strengthening of the mechanical stress leads to an increase in the power cost of the equipment and the like, causing a problem of cost reduction. For this reason, the deinking agent is required to have strong ink releasability for reducing the amount of unpeeled ink and the ability to more efficiently remove free ink by flotation in the current mainstream flotation method.

  Conventional high alcohol nonionic surfactant type deinking agents (see Patent Document 1, Patent Document 2 and Patent Document 3) cannot sufficiently separate the ink, leading to deterioration of the quality of the deinked pulp. There is. An alkylphenol nonionic deinking agent obtained by adding a long-chain alkylene oxide such as alkylene oxide or alkylene oxide and α-olefin oxide to phenol or alkylphenol (see Patent Documents 4, 5, and 6) is a flotation method. In the deinking method, there is a problem that the removability of free ink is lowered.

On the other hand, in the flotation method, the phenolic deinking agent may have significantly different foaming behavior than the higher alcohol deinking agent. For example, an alkylene oxide adduct of tristyrenated phenol tends to increase the foaming amount during flotation, and there is a problem that the pulp yield decreases due to an increase in the outflow froth amount resulting from this. In addition, the deinking agent is subjected to coagulation sedimentation treatment and microbial treatment in an aeration tank after use, and then released as wastewater to the outside of the system. However, if the phenolic deinking agent is insufficiently biodegradable, There is also a problem that it takes time for processing and the like, and it is released outside the system without being sufficiently decomposed.
JP 55-51891 A JP 55-51892 A JP-A-8-284087 Japanese Patent No. 2645208 Japanese Patent No. 2810477 Japanese Patent No. 2810477

  The object of the present invention is to obtain a high-quality pulp with high whiteness and a small amount of residual ink regardless of the type of used printed paper, and with good whiteness and low residual ink content. It is to provide a deinking agent.

（式中、Ｒは炭素数１３〜１７のアルケニル基を表し、ＡＯは炭素数２〜４のオキシアルキレン基を表す。ｎは１〜３００の整数であって、ｎ個のＡＯは同一であっても異なっていてもよい。） As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found an optimal deinking agent for used paper recycling for the above-mentioned problems, and have completed the present invention. That is, the present invention relates to a deinking agent for used paper recycling, comprising a compound obtained by adding alkylene oxide to one or more alkenylphenols represented by the following general formula (1).

(In the formula, R represents an alkenyl group having 13 to 17 carbon atoms, AO represents an oxyalkylene group having 2 to 4 carbon atoms, n is an integer of 1 to 300, and n AOs are the same. Or different.)

  As a preferred embodiment of the present invention, there is a deinking agent for used paper recycling in which one or more of the alkenylphenols are cardanol.

  In the deinking method using the flotation method, when the deinking agent for used paper recycling (hereinafter also referred to as “the product of the present invention”) according to the present application is added to the deinking process, it is compared with the current mainstream higher alcohol deinking agent. As a result, a significant improvement in the releasability of the ink is confirmed. In addition, the conventional alkylene oxide adducts of phenol and alkylphenol have greatly reduced free ink removability in the deinking method by the flotation method, but such cases are not confirmed in the products of the present invention. In other words, compared with the conventional deinking agent, the product of the present invention reduces the amount of residual ink in the completely washed DIP in which the DIP after deinking by the flotation method is completely washed with water, and is not peeled off from the pulp. It has the two effects of reducing the amount of ink and improving the removability of free ink. Although the detailed mechanism for exerting such an effect is unknown, in general, a deinking agent having a phenol skeleton tends to reduce the amount of unpeeled ink of a completely washed DIP as compared with a higher alcohol deinking agent. Is considered to contribute to the reduction effect of unpeeled ink. On the other hand, the amount of foaming and outflow froth of the product of the present invention is at the same level as the higher alcohol deinking agent.

  In the general formula (1), R represents an alkenyl group having 13 to 17 carbon atoms. The structure of R is not particularly limited, but the number of unsaturated bonds may be one or more, and may be a linear structure or a branched structure. It is particularly preferred if it has a structure and has 15 to 17 carbon atoms.

  The alkenylphenol alkylene oxide adduct of the present invention may be produced by any method. Usually, it can obtain by the method of adding an alkylene oxide to 1 type, or 2 or more types of an alkenyl phenol under a basic catalyst.

The alkenylphenol includes a pure product or a mixture of a plurality of types produced industrially, and a pure product or a mixture of a plurality of types extracted from a natural product such as a plant. For example, 3- [8 (Z), 11 (Z), 14-pentadecatrienyl] phenol, 3- [8 (Z), 11 (Z)-, which is extracted from cashew nut shell and the like and collectively called cardanol Pentadecadienyl] phenol, 3- [8 (Z) -pentadecenyl] phenol, 3- [11 (Z) -pentadecenyl] phenol, 3- [8] extracted from ginkgo seeds and leaves, Nurde leaves, etc. (Z), 11 (Z), 14 (Z) -Heptadecatrienyl] phenol, 3- [8 (Z), 11 (Z) -heptadecadienyl] phenol, 3- [12 (Z) -heptadecenyl ] Phenol, 3- [10 (Z) -heptadecenyl] phenol and the like. Of these, cardanol having good decomposability ^* can be preferably used.
* Source: National Institute of Technology and Evaluation (NITE) website

  In the general formula (1), AO represents an oxyalkylene group having 2 to 4 carbon atoms, and specific examples include an oxyethylene group, an oxypropylene group, and an oxybutylene group. n is an integer of 1 to 300 and represents the number of added moles of alkylene oxide. In terms of obtaining desired performance according to the present application, n is preferably 5 to 200, more preferably 10 to 100, and particularly preferably 20 to 50. The n AOs may be the same or different, but those having both an oxyethylene group and an oxypropylene group are preferred in terms of improving the floatability. When it has a plurality of types of oxyalkylene groups, either block addition or random addition may be used.

  The deinking agent for used paper recycling of the present invention contains the compound represented by the general formula (1), and the used deinking agent for used paper recycling comprises a used paper de-aggregation step, a bleaching step, and a flotation step. The deinking process such as the above may be added in a divided manner, or may be added in a lump to the used paper disaggregation process. The amount of the compound represented by the general formula (1) is preferably 0.05 to 3.0% by mass with respect to waste paper.

  In addition, anionic surfactants such as alkyl ether sulfates and fatty acid soaps, and ink collection properties by flotation are used for the purpose of adjusting foaming and foam suppression properties within the range that does not impair the deinking performance. Fatty acids and solvents to be improved, (terpene alcohols) can also be used. Furthermore, alkalis such as caustic soda, sodium silicate, sodium carbonate and sodium phosphate, and chelating agents such as EDTA can also be used. In addition, a whitening degree of DIP can be increased by using a bleaching agent such as hydrogen peroxide together. When a bleaching agent is used, it is usually used in a proportion of 0.1 to 20% by mass relative to the used paper, and when an alkaline agent is used, it is usually used in a proportion of 0.1 to 10% by mass with respect to the used paper. Water is used at a rate of 100 to 3000% by weight of the waste paper in order to facilitate the weaving of the waste paper pulp.

  The deinking agent of the present invention can be used for various types of used printing paper such as newspapers, magazines, books, OA copying used paper, flyers, etc., and also for various printing methods such as letterpress printing, offset printing, and gravure printing. Yes.

(Synthesis of deinking agent for Example)
Next, the present invention will be described in more detail with reference to examples.
(Synthesis of cardanol alkylene oxide adduct)
Cardanol (3- [8 (Z), 11 (Z), 14-pentadecatrienyl] phenol 31% by mass, 3- [8 (Z), 11 (Z) -pentadecadienyl] phenol 20% by mass, 3- [8 (Z) -pentadecenyl] phenol 45% by mass, trade name: Distilled
83.6 g of Cashew Nut Shell Liquid (made by SATYA CASHEW CHEMICALS, India) and 1.3 g of potassium hydroxide were put into a stainless steel autoclave, the inside of the system was purged with nitrogen, and the temperature was raised to maintain 120 ± 5 ° C. Then, the system was depressurized and dehydrated under reduced pressure of 50 mmHg for 1 hour. After completion of dehydration under reduced pressure, the system was returned to atmospheric pressure with nitrogen, and a mixture of 243 g of ethylene oxide (20 mol per 1 mol of cardanol) was gradually added and added so as to maintain 120 ± 5 ° C. and 0.1 to 0.5 MPa. Reaction was performed. After completion of the addition reaction, aging was performed while maintaining 120 ± 5 ° C. for 2 hours. After completion of the addition, the catalyst was neutralized with 1.6 g of acetic acid to obtain compound A-1 shown in Table 1.

  Thereafter, the compounds A-2 to A-10 shown in Table 1 were obtained in the same manner. In the structural formulas in the following table, “/” indicates that the addition form of the alkylene oxide is random addition, and “−” indicates that the addition is block addition.

(Deinking agent for comparative example)
In order to perform a performance comparison with a conventional higher alcohol deinking agent, the comparative compounds shown in Table 2 were used. The synthesis method of the comparative compound was in accordance with the method described in [0016].

(Deinking test method)
Cut the raw paper into 3cm x 3cm, put it in a table top breaker, 1.5% caustic soda (against waste paper), 3% sodium silicate (against waste paper), 35% hydrogen peroxide 3% ( After adding the deinking agent, water was added to make the waste paper concentration 5%, the temperature was raised to 55 ° C., and the mixture was disaggregated for 15 minutes. After disaggregation, the mixture was aged at the same temperature for 1 hour, diluted to a pulp concentration of 1%, transferred to a floatator, and subjected to a flotation treatment for 10 minutes. The obtained pulp was adjusted to 0.5% concentration, adjusted to pH 5.0 with aluminum sulfate, and then hand-drawn with a sheet machine defined in JIS P-8209. Further, the pulp subjected to the flotation treatment was washed three times with 200 times the amount of ion-exchanged water. This pulp was similarly hand-papered with a sheet machine specified in JIS P-8209.

(Performance evaluation test)
Foamability with a flotator: The foam height (mm) from the liquid level after 1 minute of flotation was measured. The handmade paper was dried and then subjected to the following measurements to evaluate the deinking effect.
Whiteness: Measured according to the method defined in JIS P-8123.
Number of remaining inks and area ratio: An image analysis apparatus was used for the completely washed pulp, and the number of inks having a diameter of 20 μm or more existing in a visual field of 100 mm ² and the total ink area ratio (%) in the entire visual field were measured.

(Example 1)
The test was performed by the method described in the deinking test method using the raw paper made of 60% offset newspaper waste paper and 40% insert advertisement, and the evaluation was performed by the method described in the performance evaluation test. The results are shown in Table 3.

By using the deinking agent for recycling used paper of the present invention, a deinked pulp having high whiteness and a small amount of residual ink was obtained. Therefore, according to the present invention, regardless of the type of used printed paper, high-quality recycled pulp having good ink peelability and detached ink removal, high whiteness, and low residual ink amount can be obtained.

Claims (2)

A deinking agent for used paper recycling, comprising a compound obtained by adding alkylene oxide to one or more alkenylphenols represented by the following general formula (1).

(In the formula, R represents an alkenyl group having 13 to 17 carbon atoms, AO represents an oxyalkylene group having 2 to 4 carbon atoms, n is an integer of 1 to 300, and n AOs are the same. Or different.) The deinking agent for used paper recycling according to claim 1, wherein one or more of the alkenylphenols are cardanol.