JPH0689517B2 - Deinking agent - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deinking agent used for recycling used paper such as newspapers, magazines and OA used paper. More specifically, a deinking agent capable of obtaining a deinked pulp having a high b value and less unpeeled ink when deinking a newspaper, a magazine, OA waste paper, etc., by a flotation method, a washing method and an eclectic method thereof. Regarding

[0002]

2. Description of the Related Art Newspapers,
Recycling of magazines, OA waste paper, etc. has been done for a long time, but in recent years, especially in connection with global environmental problems such as forest resource protection and waste disposal, the effective use of waste paper is becoming more important. Further, the use of deinked pulp has been advanced to higher-grade pulp, as can be seen from the example of used newspaper to medium-quality paper. On the other hand, the recent waste paper is becoming more severe from the viewpoint of deinking due to changes in printing technology, printing method, printing ink components, and the like. For this reason, in order to further promote deinking, improvements have been made to the apparatus. Chemicals that have been conventionally used to separate and remove ink and other impurities from waste paper include alkaline agents such as caustic soda, sodium silicate, sodium carbonate, sodium phosphate, hydrogen peroxide, hyposulfite, and hypochlorite. Anion activity such as alkylbenzene sulfonate, higher alcohol sulfate ester salt, α-olefin sulfonate, dialkyl sulfosuccinate as deinking agent together with bleaching agent such as acid salt and sequestering agent such as EDTA and DTPA Nonionic activators such as agents, higher alcohols, ethylene oxide adducts of alkylphenols and fatty acids, and alkanolamides have been used alone or in combination of two or more. However, these deinking agents have a large foaming property in the flotation process, but have a low ink-collecting ability, and the cleaning method has a weak cleaning power, and the high foaming property causes foaming troubles in wastewater treatment. And resulted in only low grade deinked pulp. Furthermore, since it has dullness even with high whiteness,
There was no choice but to increase the amount of bleach used in order to eliminate the use restrictions of deinked pulp (reduction in the amount of paper below the surface of the board, reduction in the amount added to newsprint, etc.) and dullness. In order to obtain a deinked pulp having a dull and bright tone, the b value of the Hunter color difference type Lab display system may be increased. Deinked pulp with a high b value shows a high removal rate of fine ink of 4 μm or less. When the b value is high, the color tone of the pulp becomes lighter, so that it is possible to reduce the amount of bleaching agent such as hydrogen peroxide used, to add a high amount of deinking pulp, and to use it for one grade application.

There are two methods for increasing the b value, and there is a method of efficiently removing the fine ink of 4 μm or less as described above or using a large amount of alkalis.
However, the latter has the drawbacks of increased stickiness (sticky substances), increased drainage load and embrittlement of pulp. Some examples of the former technique for collecting and removing fine ink of 4 μm or less have been shown, but none have been effective.

Higher fatty acids have long been known as a deinking agent having a large ink collecting ability. For example, Japanese Patent Registration No. 80988, Japanese Patent Registration No. 82089, and Japanese Patent Registration No. 83901 disclose use as a deinking agent having excellent ink collecting ability when used alone. Further, JP-A-51-13762, JP-A-53-130309, and JP-A-54-6840.
Japanese Patent Publication No. 3 discloses that even more excellent effects can be obtained by using it together with other surfactants.

Thereafter, with the development of technology, the invention of a high-performance deinking agent comprising a compound obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide and remarkably improving the whiteness of deinking pulp was made ( JP-A-58-109696, JP-A-59-13
0400).

However, even if the deinking agents disclosed in these techniques were used, it was not possible to obtain deinked pulp having a high b value. Further, when a conventionally known higher fatty acid or a salt thereof is used, there is a drawback that the amount of unpeeled ink is large.

[0007]

The inventors of the present invention have shown excellent ink removing ability in flotation method, washing method and their eclectic method and have good operability. As a result of intensive research to develop a deinking agent capable of obtaining a small amount of deinked pulp, surprisingly, it is a mixture of a higher fatty acid having 8 to 24 carbon atoms or a salt thereof, and the fatty acid or the fatty acid in the mixture is The average carbon number of the salt is in the range of 12.7 to 22.5, the content of the higher fatty acid having 20 to 24 carbon atoms or the salt thereof is 9.6 to 70.6% by weight, and the iodine value (IV) is
The inventors have found that a mixture having a ratio of 45 or less can overcome the above-mentioned drawbacks, and completed the present invention.

That is, the present invention contains a higher fatty acid having 8 to 24 carbon atoms or a salt thereof in the range of an average carbon number of 12.7 to 22.5, and the content of the higher fatty acid having 20 to 24 carbon atoms or a salt thereof is
It is intended to provide a deinking agent containing a mixture of 9.6 to 70.6% by weight and an iodine value (IV) of 45 or less as an essential component.

Numerical regulations regarding the fatty acid mixture according to the present invention are critical, and even compounds similar to these are not applicable to the regulation of the present invention, the remarkable effects of the present invention cannot be obtained. Therefore, it is extremely important to limit the numerical values such as the carbon number of the compound of the present invention. As will be clarified by Examples and Comparative Examples described later, if the average carbon number is less than 12.7, the fine ink aggregation effect is lowered, and it is not possible to obtain deinked pulp having a high b value. Also, if the average carbon number is
Even if it exceeds 22.5, the foaming property in the flotation process is insufficient, and the cohesive ink is less likely to be rejected to the outside of the system. Also,
When the content of the fatty acid having 20 to 24 carbon atoms is less than 9.6% by weight, the fine ink aggregation effect is deteriorated, so that the deinked pulp having a high b value cannot be obtained. On the other hand, if it is more than 70.6% by weight, the ink releasability becomes weak, and a large amount of unpeeled ink remains, and as a result, only deinked pulp with a poor appearance is obtained. The compound of the present invention may optionally contain a fatty acid having 8 to 24 carbon atoms within the scope of the present invention. In particular, it is preferable to contain a fatty acid having 20 carbon atoms or a salt thereof in an amount of 2.0 to 33.2% by weight and a fatty acid having 22 carbon atoms in an amount of 9.5 to 32.0% by weight.

If the iodine value (IV) is larger than 45,
The foaming property in the flotation step is insufficient, and the agglomerated ink on the foam layer is not easily rejected outside the system, and as a result, only deinked pulp with low whiteness can be obtained. Furthermore, since the ink releasability is low, a large amount of unpeeled ink remains.

The deinking agent of the present invention has a carbon number of 8 as described above.
~ 24 fatty acids and salts thereof can be arbitrarily blended within the scope of the present invention, specifically, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid,
Myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, oleic acid, elaidic acid, linoleic acid, linoleic acid, stearolic acid, ricinoleic acid, ricinoelaidic acid, nonadecanoic acid, arachidic acid, henicosanoic acid, behenic acid , Brassic acid, erucic acid, tricosanoic acid, tetracosanoic acid, coconut oil fatty acid, beef tallow fatty acid, palm oil fatty acid, tall oil fatty acid, rapeseed oil fatty acid, fish oil fatty acid, or these semi-hardened or hardened fatty acids, and all these fatty acids You can list the salt. Examples of the salt include sodium salt, potassium salt, ammonium salt, magnesium salt, calcium salt and the like. Among these, semi-hardened or hardened fish oil fatty acid or a salt thereof is preferable from the viewpoint of cost and ease of use alone. Fish oil which is a raw material of the fish oil fatty acid of the present invention, cod oil, sardine oil, saury oil, mackerel oil, herring oil,
Menhaden oil and the like and recovered oil obtained in these refining steps and the like can be mentioned.

Although it has been known in the prior art to use a higher fatty acid as a deinking agent, it is completely known that such a deinking effect is exhibited only by a mixture containing a fatty acid having a specific carbon number in a specific ratio. Didn't. That is, the prior art has merely used the anionic surfactant derived from coconut oil or tallow oil or the higher fatty acid generally used as a raw material thereof without being concerned with the carbon number. The prior art does not disclose the use of higher fatty acids in specific proportions. Even in the above patent publications, none of the examples use the fatty acid mixture disclosed in the present invention.
Further, these are mainly composed of fatty acids having 12 to 18 carbon atoms, which is clearly different from the scope of the present invention.

One of the fatty acids used in the present invention is fish oil fatty acid or its salt. Prior art JP-A-61-89394, JP-A-62-250291
In the publication, although the use of fish oil fatty acid containing a fatty acid having 20 or more carbon atoms is used in combination, no specific example is described, and the removal of fine ink of 4 μm or less according to the present invention results in b
The effect is different from the effect of increasing the value.
Furthermore, the present invention is essential to have a certain iodine value (IV), and the above-mentioned conventional fish oil fatty acid has an iodine value (IV) of about 175, and the fish oil fatty acid itself has an iodine value (IV). It is too expensive to use for this purpose.

Since the deinking agent of the present invention exhibits a sufficient deinking effect even when used alone, it may be used in combination with another surfactant.
It is not necessary to add alkylene oxide. Therefore, an industrially extremely useful invention is disclosed in which not only the deinking performance but also the steps of manufacturing and blending the deinking agent are simplified, and the versatility and safety are improved accordingly.

Most of the fatty acids which are the constituent components of the deinking agent of the present invention are derived from natural fats and oils, and the conventional methods for producing fatty acids include Twitchell decomposition, intermediate pressure catalytic decomposition and continuous high pressure decomposition methods. is there. Further, as a general method for lowering the iodine value (IV), a method of performing hydrogenation under high temperature and high pressure using a nickel catalyst can be mentioned.

The deinking agent of the present invention is a known deinking agent, for example, higher alcohol sulfates, alkylbenzene sulfonates, ethylene oxide adducts of higher alcohols and alkylphenols, fatty acids and salts thereof, fatty acid alkylene oxide adducts, Fat alkylene oxide adduct, monostearyl glyceride alkylene oxide adduct, polyhydric alcohol partial ester or complete ester alkylene oxide adduct and the like also when used in combination with a higher fatty acid having 20 to 24 carbon atoms or its salt content 9.6 to 70.6
When it is within the range of weight%, excellent deinking performance is exhibited.
When the deinking agent of the present invention and a conventionally known deinking agent are used in combination,
The combination ratio of the present invention product / conventional product = 90/10 to 10/90
(Weight ratio) is preferable, but 20/80 to 60 is particularly preferable.
/ 40 (weight ratio).

Even if the deinking agent of the present invention is added to any step, a higher quality deinking pulp can be obtained. Generally, the deinking agent is added to either or both of the mixing step and the flotation step, but when water with high hardness is used, the method of adding it immediately before the flotation step is preferable. When adding in divided steps,
It can be added to each process of pulping, kneading, dispersing, chemical mixing and refining, but the division ratio of the deinking agent in the previous process and the subsequent process is 10/90 to 90 /
10 (weight ratio) is preferable. Particularly preferably 40 / 60-60
/ 40 (weight ratio). Although it is desirable that the amount of deinking agent added be economical without impairing operability,
0.03 to 1.0% by weight is preferred.

[0018]

Function The mechanism of the deinking agent of the present invention is not clear yet,
It can be considered as follows. As the carbon number of the higher fatty acid increases, the adsorption orientation on the surface of the fine ink becomes almost vertical, so that the density of functional groups at the terminal of the deinking agent becomes sparse. Therefore, the absolute value of the surface charge density per unit area becomes small, and it is considered that the fine ink tends to aggregate according to the DLVO theory. In particular, if the content of the higher fatty acid having 20 to 24 carbon atoms is less than 9.6% by weight, the fine ink will not easily aggregate. On the other hand, if the content exceeds 70.6% by weight, the adsorption speed on the ink surface decreases rapidly, and the ink surface charge density control by the deinking agent becomes insufficient. Therefore, the fine ink is less likely to aggregate. As described above, if the content of the higher fatty acid having 20 to 24 carbon atoms is in the range of 9.6 to 70.6% by weight, the fine ink is aggregated, and as a result, a deinked pulp having a high b value can be obtained.
Further, reduction of unpeeled ink is possible by reducing the interfacial tension between the ink and cellulose. Carbon number 20-24
When the content of the higher fatty acid in 7 is more than 70.6% by weight, the critical micelle concentration rapidly increases, so that the action is below the critical micelle concentration in the actual deinking process, and the sufficient ink peeling force is not exhibited. As described above, in order to satisfy both functions of excellent fine ink aggregation ability (which gives a high b value) and reduction of unpeeled ink, the content of the higher fatty acid having 20 to 24 carbon atoms or its salt is 9.6 to There is a critical range of 70.6% by weight.

When the iodine value is large, the deinking agent is adsorbed on the ink surface almost flatly, forming a thin adsorption layer of about 10 Å, and the surface potential of the ink itself (-30 to -40 mV in ζ-potential).
Therefore, the absolute value of the surface charge density per unit area does not decrease. Therefore, the fine ink is less likely to aggregate.

From the above, it is possible to obtain a deinked pulp having a high b value and less unpeeled ink within the range specified in the present invention.

[0021]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto.

Example 1 This example is an example of batch addition of a deinking agent in the pulping step. After collecting the recovered newspaper waste paper into 2 x 5 cm pieces, put a certain amount into a table disintegrator, and water and caustic soda (vs. raw material) 0.8%, sodium silicate No. 3 (vs. raw material) 2.2%, 30% % Hydrogen peroxide (vs. raw material) 3.5% and deinking agent (vs. raw material) 0.5% shown in Table 1 were added, pulp concentration was 15%, 12 pieces were separated at 45 ° C, and then aged at 55 ° C for 120 minutes. went. Then, it was dehydrated to 23% with a high-speed dehydrator, and subjected to a kneading treatment with a twin-screw lab kneader with a rotation speed of 300 rpm. Then, add water to dilute it to 4% and disintegrate again for 30 seconds with a table disintegrator. After diluting the slurry to 1% with water, 10
Flotation treatment was performed for a minute. Note that 0.5% of CaCl ₂ (vs. raw material) was added during flotation. After the flotation, the pulp slurry was concentrated with an 80-mesh wire to a concentration of 4%, water was added to dilute it to a concentration of 1%, and a pulp sheet was prepared with a tappy standard paper machine. In addition,
The hardness of the water used was 5 ° dH and the hardness was CaCl ₂ , MgCl ₂ .
₂ was used and adjusted so that Ca / Mg = 8/2 (molar ratio). The b value of the obtained pulp sheet was measured with a colorimetric color difference meter, and the number of unpeeled inks was measured with an image analyzer (× 100). The b value here is La in the Hunter color difference formula.
b The b value in the color system, which has the following relationship with the tristimulus values XYZ.

[0023]

[Equation 1]

As can be seen from this expression, the b value is a function of Y and Z, and a positive value represents yellowish intensity, and a negative value represents bluish intensity. Average carbon number and carbon number of the deinking agent of the present invention 20 ~
Table 2 shows the deinkability of the system in which the content ratio of 24 fatty acids was changed. The deinking agent in Table 1 is a mixture of fatty acids so as to have a predetermined carbon number composition. Further, No. 19 is stearic acid.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

Example 2 This example is an example of the splitting addition of the deinking agent and the chemical mixing step divided addition. The newspaper collected in the market is shredded into 2 x 5 cm pieces, and a certain amount is put into a table disintegrator, and water and caustic soda (vs. raw material) 0.2% and deinking agent (vs. raw material) 0.1% shown in Table 3 are put in it. In addition, the pulp concentration was 15% and 12 pieces were separated at 45 ° C, and then aged at 55 ° C for 120 minutes. Then, dehydrate to 23% with a high-speed dehydrator, and use 0.6% caustic soda (against raw materials).
%, Sodium silicate No. 3 (for raw material) 2.2%, 30% hydrogen peroxide (for raw material) 3.5%, deinking agent (for raw material) shown in Table 3 0.2%
Was added, the pulp concentration was adjusted to 22% with water, and the mixture was mixed with a table disintegrator for 1 minute. Then, a kneading process was performed with a twin-screw lab kneader with a rotation speed of 300 rpm. Then, add water to dilute it to 4% and disintegrate again for 30 seconds with a table disintegrator.
The slurry was diluted to 1% with water and then subjected to flotation treatment at 30 ° C for 10 minutes. Incidentally, 0.4% of CaCl ₂ (vs. raw material) was added during flotation. After the flotation, the pulp slurry was concentrated to a 4% concentration with an 80-mesh wire, water was added to dilute the concentration to 1%, and a pulp sheet was produced using a tappies tandart paper machine. The hardness of the water used was 5 ° dH, and the hardness was adjusted to Ca / Mg = 8/2 (molar ratio) by using CaCl ₂ and MgCl ₂ .
The b value of the obtained pulp sheet is measured with a colorimetric color difference meter,
The number of unpeeled inks was measured with an image analyzer (× 100 times). Table 4 shows the results of deinking property when the iodine value (IV) of various deinking agents changed.

The deinking agents shown in Table 3 are prepared by mixing fatty acids so as to have a predetermined carbon number composition.

[0030]

[Table 4]

[0031]

[Table 5]

Example 3 This example is an example of adding a deinking agent in a pulping step and a kneading step. The newspaper collected in the market is shredded into 2 x 5 cm pieces, and a certain amount is put into a table disintegrator, and 0.2% of water and caustic soda (vs. raw material) and 0.3% of the deinking agent (vs. raw material) shown in Table 5 are put in it. In addition, the pulp concentration was 15% and 12 pieces were separated at 45 ° C, and then aged at 55 ° C for 120 minutes. Then, dehydrate to 23% with a high-speed dehydrator, and use 0.6% caustic soda (against raw materials).
%, Sodium silicate No. 3 (for raw material) 2.2%, 30% hydrogen peroxide (for raw material) 3.5%, deinking agent (for raw material) shown in Table 5 0.2%
Was added, the pulp concentration was adjusted to 22% with water, and the mixture was mixed with a table disintegrator for 1 minute. Then, a kneading process was performed with a twin-screw lab kneader with a rotation speed of 300 rpm. Then, add water to dilute it to 4% and disintegrate again for 30 seconds with a table disintegrator.
The slurry was diluted to 1% with water and then subjected to flotation treatment at 30 ° C for 10 minutes. Note that 0.5% of CaCl ₂ (vs. raw material) was added during flotation. After the flotation, the pulp slurry was concentrated to a 4% concentration with an 80-mesh wire, water was added to dilute the concentration to 1%, and a pulp sheet was produced using a tappies tandart paper machine. The hardness of the water used was 10 ° dH, and the hardness was adjusted to Ca / Mg = 8/2 (molar ratio) by using CaCl ₂ and MgCl ₂ . The b value of the obtained pulp sheet was measured with a colorimetric color difference meter, and the number of unpeeled inks was measured with an image analyzer (× 100). Table 6 shows the results of deinking performance of various deinking agents. The deinking agents in Table 5 are cod up to No.37-40,
Hardened product of sardines, saury, mackerel oil fatty acid, No. 41
Is a 50/50 (weight ratio) mixture of Nos. 37 and 38. Nos. 42 to 44 are No. 37 deinking agents having a changed iodine value (IV). Further, Nos. 45 to 49 are stearic acid, myristic acid, commercially available stearic acid (Kao Corporation, trade name Lunac S-40) and hardened tallow fatty acid and sardine oil fatty acid (iodine value (IV) = 175). Is.

[0033]

[Table 6]

[0034]

[Table 7]

Example 4 This example is an example of the splitting addition of the deinking agent before the pulping step and the flotation step. The newspaper collected in the market is shredded into 2 x 5 cm pieces, and a certain amount is placed in a table disintegrator, and 0.2% of water and caustic soda (vs. raw material) and 0.2% of the deinking agent (vs. raw material) shown in Table 7 are put in it. In addition, the pulp concentration was 15% and 12 pieces were separated at 45 ° C, and then aged at 55 ° C for 120 minutes. Then, dehydrate to 23% with a high-speed dehydrator, and use 0.6% caustic soda (against raw materials).
%, Sodium silicate No. 3 (for raw material) 2.2%, 30% hydrogen peroxide (for raw material) 3.5% were added, and the pulp concentration was adjusted to 22% with water and mixed for 1 minute with a table disintegrator. After that, the rotation speed is 300r
A kneading process was performed with a pm 2-axis lab kneader.
After that, add water to dilute it to 4%, and use a table top disintegrator again.
Disaggregate for 30 seconds. After adding 0.3% of the deinking agent (compared to the raw material) shown in Table 7 to the pulp slurry, the slurry was diluted to 1% with water and then subjected to flotation treatment at 30 ° C. for 10 minutes. The pulp slurry after flotation was concentrated with a 60-mesh wire to a concentration of 4%, water was added to dilute the concentration to 1%, and a pulp sheet was produced with a tappe tandart paper machine. The hardness of the water used was 40 ° dH, the hardness was CaCl ₂ , MgCl ₂ , and Ca / Mg = 8/2.
(Molar ratio) was adjusted. The b value of the obtained pulp sheet was measured with a colorimetric color difference meter, and the image analysis device (× 100
The number of unpeeled inks was measured. Table 8 shows the results of deinking performance of various deinking agents.

Among the deinking agents in Table 7, the fatty acid is sodium salt or calcium salt. Also, No.5
0 and 53 are fatty acid sodium salts alone, and Nos. 51 and 52 are fatty acid calcium salts blended so as to have a predetermined carbon number composition. No. 54 is sodium stearate.

[0037]

[Table 8]

[0038]

[Table 9]

As exemplified above, a mixture of a higher fatty acid having 8 to 24 carbon atoms or a salt thereof, wherein the fatty acid in the mixture has an average carbon number of 12.7 to 22.5 and a carbon number of 20 to
The content of 24 higher fatty acids or their salts is 9.6 to 70.6% by weight
And a mixture having an iodine value (IV) of 45 or less is used as a deinking agent, a deinked pulp having a high b value and less unpeeled ink can be obtained.

Claims (3)

[Claims] 1. A higher fatty acid having 8 to 24 carbon atoms or a salt thereof is contained within a range of an average carbon number of 12.7 to 22.5, and a content of the higher fatty acid having 20 to 24 carbon atoms or a salt thereof is 9.6 to 70.6.
A deinking agent containing a mixture having a iodine value (IV) of 45 or less by weight as an essential component. 2. A fatty acid having 20 carbon atoms or a salt thereof is added in an amount of 2.0 to 3
3.2% by weight and 9.5 to 32.0% by weight of C22 fatty acid
The deinking agent according to claim 1, wherein the deinking agent is contained. 3. The deinking agent according to claim 1, wherein the higher fatty acid having 8 to 24 carbon atoms or a salt thereof is a semi-hardened or hardened fish oil fatty acid or a salt thereof.