JPH0157195B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a deinking agent used when recycling used paper such as newspapers and magazines. More specifically, the present invention relates to a deinking agent that can obtain deinked pulp with high whiteness and a small amount of residual ink when deinking newspapers, magazines, etc. by a flotation method or a combination flotation/washing method. [Prior Art] Recycling of newspapers, magazines, etc. has been carried out for a long time, but in recent years, the effective use of waste paper resources has become increasingly important due to the shortage of pulp resources and the rise in their prices. Furthermore, there is an increasing demand for advanced utilization of deinked pulp. Recycling waste paper has many advantages from the viewpoint of energy conservation, urban waste management, forest resource protection, etc. On the other hand, recently, the situation with waste paper has become more difficult from the perspective of deinking due to changes in printing technology and printing methods, changes in printing ink components, etc., and improvements have also been made to equipment to further promote deinking. are being added. Chemicals traditionally used to separate and remove ink and other impurities from waste paper include alkaline agents such as sodium hydroxide, sodium silicate, sodium carbonate, and sodium phosphate, hydrogen peroxide, hyposulfite, and hypochlorite. Bleach such as acid salts, EDTA,
These are metal ion sequestering agents such as DTPA, NTA, and STPP, and conventionally known chemical substances used as deinking agents for waste paper recycling along with these are alkylbenzene sulfonates, alkyl sulfates, α-
Anionic surfactants such as olefin sulfonates, dialkyl sulfosuccinates, higher fatty acid salts, higher alcohol ethylene oxide adducts,
alkylphenol ethylene oxide adduct,
Nonionic surfactants such as fatty acid ethylene oxide adducts, fatty acid amide ethylene oxide adducts, polypropylene glycol ethylene oxide adducts, ethylene oxide adducts of fats and oils, higher alcohol ethylene oxide propylene oxide (block or random) adducts, and amines. Examples include amphoteric surfactants such as oxides and alkyl betaines. It is also a known fact that the effects can be increased by using these chemical substances together with specific organic/inorganic builders, organic solvents, etc. [Problems to be solved by the invention] However, with these chemical substances and their combinations, the deinking efficiency in the flotation process is not necessarily high, and it is difficult to obtain recycled paper with high whiteness and a low number of residual inks. It is not always possible to satisfy the requirements. For example, fatty acids and salts thereof, which have excellent ink-collecting properties in the flotation process, have a drawback that their foaming properties in the flotation process are very low, and the ink that has coagulated and floated cannot be removed sufficiently. In addition, although the conventionally known deinking surfactants described above have sufficient ink removal properties from paper in the waste paper disintegration process and foaming properties in the flotation process, they have poor ink collection properties and do not adhere to the foam layer or the foam. It has the disadvantage that the amount of ink present in the layer is small and it is difficult to remove the ink floating in the pulp suspension from the system together with the foam layer. In this way, no chemical substance has been found that has all of the properties of ink removal from paper in the waste paper disintegration process, high foaming property and high ink collection property in the flotation process, The most common method is to use objects. However, although a deinking method using this compound has some effect, it is not necessarily a satisfactory method. [Means for Solving the Problems] Therefore, the present inventors conducted intensive research to find a deinking agent that does not have the above drawbacks, and as a result, they found that a compound represented by the following general formula (1) satisfies this. The invention has been completed. That is, the present invention provides a deinking product for recycling used paper, which contains as an essential component a compound represented by the following general formula (1), which is obtained by sulfating alcohol with ethylene oxide added at an average molar ratio of 0.3 or more and less than 1. The purpose is to provide an agent for R-O-(CH ₂ CH ₂ O-) _o SO ₃ M (1) (In the formula, R represents an alkyl group or alkenyl group having 8 to 22 carbon atoms, and n is on average 0.3 or more and less than 1, preferably 0.4 0.8 or less, and M represents hydrogen, ammonium, or an alkali metal.) [Operation] The compound represented by the general formula (1) is produced by adding ethylene oxide to alcohol in the presence of an alkali catalyst, etc., and then converting it into SO ₃ It is a compound having various ethylene oxide chain lengths, and is produced by a known method of sulfating by, for example, ethylene oxide. In the present invention, compounds in which the number of theoretically added moles of ethylene oxide added in this manner is 0.3 or more and less than 1 on average, particularly compounds in which it is 0.4 or more and 0.8 or less, exhibit excellent effects. It has extremely critical meaning in the invention. In the compound represented by general formula (1), it is also important that R is an alkyl group or alkenyl group having 8 to 22 carbon atoms. The alkyl group or alkenyl group may be linear or branched. Number of carbons is 8
If the size is smaller, the ink collection property is poor and the bubble life in the flotation process is short. Also, 22
If the diameter is larger, the diameter of the bubbles generated in the flotation process is large and the ink collection efficiency is low, although some degree of ink collection performance is observed. In the general formula (1), M is hydrogen, ammonium such as NH ₄ or alkanol ammonium, or an alkali metal such as Na or K. Even when M is hydrogen, a large amount of caustic soda is present in the disintegration process, so it acts in the form of a salt. In the present invention, excellent effects can be obtained even when the compound represented by the above general formula (1) is used alone as a deinking agent, but even more excellent effects can be obtained when used in combination with a fatty acid having 8 to 18 carbon atoms or a salt thereof. Effects can be obtained. The compounding ratio of the compound represented by the general formula (1) and the fatty acid or its salt is preferably 98:2 to 2:98, more preferably 5:95 to 30:70, by weight. Specific examples of fatty acids include cabrylic acid, cabric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid. Of course, a mixture of these fatty acids may also be used. In this case, polyvalent metal salts such as calcium chloride,
It is also possible to use magnesium chloride, magnesium hydroxide, calcium hydroxide, aluminum sulfate, etc. in combination. The deinking agent of the present invention may be added to either the waste paper disintegration process or the ripening tower process, and the addition amount is sufficient to be 0.2 to 0.8% by weight based on the raw waste paper.
Further, the present invention can be used in combination with known deinking agents that have been commonly used. [Examples and Effects] The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples. The deinking performance was evaluated by measuring the whiteness of the recycled pulp sheet (using a colorimeter) and the number of remaining inks (using an image analysis device x126). Example 1 After shredding municipally collected newspaper waste into 2 x 5 cm pieces, a certain amount of it was put into a tabletop disintegrator, and water and hydroxide (sodium to raw material waste paper) of 1.5% and sodium silicate No. 3 (to the raw material waste paper) were added. (raw material used paper) 4.5%, 30% hydrogen peroxide solution (based on raw material waste paper) 1.0%, deinking agent (based on raw material waste paper) 0.2
% was added, the pulp concentration was 5%, the pulp was disintegrated at 60°C for 20 minutes, and then aged at 45°C for 90 minutes. Thereafter, water was added to dilute the pulp to 1.0%, and a flotation treatment was performed at 30°C for 10 minutes. After the pulp slurry after flotation was concentrated to a concentration of 6%, water was added to dilute it to a concentration of 1%, and a pulp sheet was produced using a TAPPI sheet machine. Table 1 shows the evaluation results of the deinking agent. In addition, in the case of a combination system with fatty acids or their salts, calcium chloride (from waste paper as raw material) is added during flotation.
0.5% was added.

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Claims (1)

[Claims] 1. General formula (1) R-O-(CH ₂ CH ₂ O- ₎ obtained by sulfating an alcohol with ethylene oxide added at an average number of moles of 0.3 or more and less than 1. SO ₃ M (1) (In the formula, R represents an alkyl group or alkenyl group having 8 to 22 carbon atoms, n is 0.3 or more and less than 1 on average, and M represents hydrogen, ammonium, or an alkali metal.) A deinking agent for waste paper recycling that contains the compound shown above as an essential component. 2. The deinking agent according to claim 1, wherein n in general formula (1) is 0.4 or more and 0.8 or less.