JPH0314685A - Deinking agent for regeneration of waste paper - Google Patents

Abstract

PURPOSE:To provide a deinking agent for the flotation deinking of waste paper to form regenerated pulp by using a specific amount of a polymer fatty acid composed of a monomer fatty acid, a dimer fatty acid and a trimer fatty acid at specific ratios. CONSTITUTION:The objective deinking agent contains 10-95wt.% of a polymer fatty acid composed of 2-70% of monomer fatty acid, 30-95% of dimer fatty acid and 2-70% of trimer fatty acid.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for obtaining deinked pulp with high whiteness when recycled pulp from used paper such as newspapers, magazines, and books is deinked by the flotation process. The present invention relates to a deinking agent for deinking and a deinking method using the same.

[Conventional technology and problems]

The following methods are known for deinking waste paper by treating it with deinking chemicals.

After or at the time of finely pulverizing waste paper with 21 Gu, bleaching agents such as alkali hydroxide and hydrogen peroxide, PL + sodium silicate as a buffering agent and chelating agent, and a surfactant (deinking agent) are used. Use deinking chemicals. At this time, a deinking agent (deinking agent) is used to efficiently remove ink from the bulb.
Examples of surfactants include nonionic surfactants such as polyoxyalkylene alkyl ether and polyoxyalkylene alkylphenol ether, and combinations of these with anionic surfactants such as oleic acid soap, higher alcohol sulfuric ester salts, and α-olefin sulfonate. Then, the ink adhering to the pulp is peeled off by keeping it at 60 to 70°C from room temperature for several hours while stirring. In order to efficiently carry out this deinking process, it is known that the pulp concentration is made as high as possible and deinking is carried out by mechanical contact between the pulps (Tokukan Roto 6-63089).

Next, the pulp solution is diluted to a concentration of around 1% and flotation is performed. At this time, ink, fillers, pigments, etc. released from the pulp are entrained by air bubbles and removed from the system. To perform flotation efficiently, higher fatty acids such as oleic acid and stearic acid, pine oil, kerosene, etc. are used to coagulate fine particles of ink separated during disintegration. (Survey report on changes in fiber strength and deinking properties during the distribution and storage stages of newspapers (used paper), S.60.3 Clean Japan Center) Insolubilized metal soap becomes flocs, and at that time ink and pigments are incorporated. They are removed from the system together with air bubbles. If only a nonionic surfactant is used, the ink particles will be small and difficult to remove when forming flocs, but if fatty acids or other soaps are used, the aggregated ink particles will become larger and the flotation effect will increase. Among fatty acids, oleic acid (CMC, published by Futanobu Yakuhin and Gion Ano Materials p. 36), stearic acid, and palmitic acid are effective. The fatty acids are introduced in free form or in the form of their soaps. When it is added in its free state, it functions as a soap due to the alkali added during disintegration. In the case of fatty acids, liquid oleic acid is the most commonly used because it has good workability and is highly effective. Oleic acid has a high cohesive force against ink and can efficiently remove ink during flotation. However, when oleic acid is used, foaming is poor, and the flocs in the coagulated and floated part of the ink have poor affinity with the foam, resulting in ink flocs separated from the flotation device adhering to the piping system of the device.
This could leak out all at once, causing problems in the process.

Furthermore, when trying to use stearic acid and palmitic acid as soap, they have a low solubility in water, which causes the inconvenience of requiring new dissolving equipment. Despite its existence, it had the drawback of being difficult to use.

[Problem to be solved by the invention]

When conventionally used fatty acids are used, as mentioned above,
The aim is to solve various problems in deinking operations, such as handling problems with deinking agents, further improving the cohesive force of disintegrated ink, and improving the fluidity of flocculated floating ink. [Means for solving the problem] In order to solve the above problems, as a result of various studies, polymerized fatty acid (commonly known as dimer acid), which is obtained by polymerizing liquid fatty acids whose main components are oleic acid, Ig', oleic acid, etc. , trimer acid) as a deinking agent during flotation, it was found that the cohesive force of the ink was significantly higher than conventionally used fatty acids such as oleic acid, baltanic acid, and stearic acid, and the present invention was completed. Furthermore, since dimer acid is liquid at room temperature, it is easy to handle.

The above polymerized fatty acid as a deinking agent may be added at the same time during the so-called defibration operation in which caustic soda, sodium silicate, soda carbonate, bleach, etc. are added, but it may also be added during the flotation operation after defibration. ．． Polymerized fatty acids themselves have inferior cleaning power for used paper compared to nonionic and anionic fatty acids, which have large HLB and are used for cleaning deinking. Therefore, since a sufficient deinking effect cannot be achieved with polymerized fatty acids alone, it is preferable to use them in combination with nonionic and/or anionic fatty acids.

Polymerized fatty acids can be used as they are, but they can also be used as alkali metal salts, ammonium salts, and amine salts. When using free fatty acids as they are, their viscosity is higher than that of ordinary liquid fatty acids such as oleic acid, so alcohols, ketones, aromatic hydrocarbons, aliphatic hydrocarbons, and other solvents may be used as long as they do not reduce the antifoaming effect. It is preferable to dilute with water to lower the viscosity before use. When used as a salt, for example, it can be saponified with an aqueous solution of caustic soda at room temperature or higher and used as a several percent aqueous solution at room temperature. Also, H
It is also possible to use a surfactant having an LB of 5 to 10 by mixing it in a ratio of 5 to 30 parts per 100 parts of the polymerized fatty acid and adding water to make an emulsion.

Further, the polymerized fatty acid can be used in combination with conventionally used oleic acid, stearic acid, palmitic acid, etc., which are added for the purpose of achieving an ink aggregation effect. The mixing ratio is not particularly specified, but the anions added during disintegration,
Since the amount of foaming varies depending on the type of nonion, the deinking device, the type of waste paper, etc., it is advisable to select an appropriate blending ratio. For example, when mixed with oleic acid, the amount of foaming tends to decrease as the amount of oleic acid added increases.

The composition of the polymerized fatty acid is preferably in the range of 2 to 70% monomer, 30 to 95% dimer, and 2 to 70% trimer. When the monomer content exceeds 70%, when the content is 10.1 to 0.4% based on the pulp used for normal deinking, the foaming suppressing effect of the unsaturated acid monomer becomes strong, and the ink that flows out with foam during flotation becomes strong. As a result, the viscosity of the floating ink increases, which is disadvantageous. Further, the cohesive force and foaming power of the ink of the trimer component are almost the same as those of the dimer, but when the content thereof increases, the viscosity of the polymerized fatty acid increases rapidly, making handling difficult. Therefore, considering the efficiency during production and use of polymerized fatty acids, it is practical to use fatty acids that mainly contain dimer acids and less trimer acids.

The amount added varies depending on the type of waste paper, the difference in deinking equipment, the type of surfactant used, etc., but it is 0.01 per dry waste paper.
~1.0wt%. [Example] The present invention will be described below with reference to Examples, but the present invention is not limited thereto.

Basically Japan TAPPI k3 9 8
2, with some modifications.

The used paper used was Asahi Shimbun, which was published in Tokyo for three months. 1800III If! ．． Add the specified amount of polymerized fatty acids to dry old paper in hot water at over 50°C, add 1.0% of 30% hydrogen peroxide solution, and 75g of old newspaper crushed with Schrader.
Put it in a standard disintegrator made by Toyo Tester■, and heat it at 50℃ for 10 minutes.
Disintegrate for minutes. After that, leave it for 160 minutes at 50°C,
Disintegrate in the disintegrator for 5 minutes as well.

Take 150g of disintegrating solution 1 and dilute it with water to obtain a pulp density of 1.
%, set the temperature to 34-36°C, and floated for 10 minutes using a flow taker manufactured by Kumagai Riki ■.

Calcium chloride was added at 38 ppm during stirring before the start of air supply.
Then, add a predetermined amount of polymerized fatty acid soda aqueous solution.

While removing foam at 3, 7, and 10 minutes during flotation, the amount of foam flowing out during flotation, the height of foam, and changes over time in foam color are tracked. After flotation, 1.0 ffi is taken and squeezed on a 60 mesh sieve to give about 90-95 g, diluted with filtrate to obtain loog, diluted with water to return to 1.0 liter, and a finished liquid is obtained.

Dissolve the disintegration liquid, flotation completion liquid, and finishing liquid uniformly on 3.0 g of waste paper and apply JIS P 8.
Test handsheets were prepared according to 209. The whiteness was measured according to Hunter Whiteness JIS P 8123.

In the conventionally used oleic acid (Comparative Example 2) and palmitic acid/stearic acid mixture (Comparative Example 3), the amount of foam flowing out was only a few percent, and the deinking effect (L) in the flotation process was small.
) (<b) - tat ) Although it is small by 2.2 years, by using polymerized fatty acids (Examples 1 to 4), the amount of foam flowing out was increased to about 10 to 15%, and the amount of foam was increased by 10 to 15% in the flotation process. Deinking effect (1) ((b)-(a)
) has increased approximately 2 to 3 times to 4.3 to 5.6, and polymerized fatty acids have a better balance of foaming properties and ink cohesive properties compared to conventionally used oleic acid, palmitic acid, stearic acid, etc. The deinking effect (2) ((C)-(a)) of 3. 8-3. 9 to 5. 6-7
．． It increased to 0.

In addition, as shown in Example 9, nonion A was increased from 0.08% to 0.15%, and a small amount of polyoxyethylene alkylphenol, which has great detergency and foaming power but has weak ink cohesiveness, was coexisting. Compared to the case (Example 6), the amount of foam flowing out increased from 13.7% to 20.0%, and the foam height at 3 minutes, 7 minutes, and 10 minutes during flotation was the same as Example 6. So 30iua, 20mm, 5
mm, whereas in Example 9 it was 35 mm, 35 mm.
mm and 20 mm, and smooth outflow of the foam was observed throughout the entire flotation period of 10 minutes. At the same time, deinking effects (1) and (2) are 0.8 and 0.8, respectively.
5, and the whiteness after finishing was also improved from 74.7 to 75.2.

Furthermore, in Comparative Example 5 and Example 10, approximately 1/2 of sulfonic acid surfactant was added to the nonionic surfactant, and the presence or absence of dimer acid was compared. 3 minutes and 7 minutes during flotation in the absence and coexistence of dimer acid.
bubble height at 10 minutes, 5 mm, 5 mm, 30 mm
Example 1 in which dimer acid coexisted
At 0, the diameter changed to 40 mm, 50 mm, and 20 mm, and smooth outflow of foam was observed throughout the flotation period, demonstrating the effectiveness of the dimer acid.

Enemy applicant Ajinomoto Co., Inc.

Claims (1)

[Claims] 1) Monomer fatty acid 2-70%, dimer fatty acid 30-70%
A deinking agent for recycling waste paper containing 10 to 95% by weight of polymerized fatty acids consisting of 95% and 2 to 70% of trimer fatty acids. 2) In the process of deinking waste paper by treating it with deinking chemicals, 10 to 95% by weight of polymerized fatty acids, which are 2 to 70% monomer fatty acids, 30 to 95% dimer fatty acids, and 2 to 70% trimer fatty acids, are added. A method for deinking used paper, characterized by using a deinking agent for recycling used paper comprising: