JPH0541750B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a pitch control agent. [Prior Art] Countermeasures against pitch troubles in pulp and paper manufacturing processes have been an important issue for a long time. Pitch is a substance that is inevitably mixed in in paper mills, and is mainly used in wood chips, waste paper pulp,
Other than those brought in from rosin sizing agents, etc. and removed from the system along with waste water, and those that are further incorporated into paper, they are accumulated in each process of cooking, beating, and paper making, and are circulated within the system. ing. Furthermore, the pulp processing equipment of each process, the walls of the pulp slurry storage chest, the wires on the paper machine,
Aggregated pitch particles adhere to press rolls, dryer rolls, blankets, canvases, etc., causing various problems. Conventional countermeasures include, for example, strengthening the seasoning of the raw material wood, strengthening the cleaning of the raw material pulp, selecting raw materials with less pitch, suppressing foaming of raw materials: white water, surfactants, water-soluble polymer dispersants, Methods include adding protective colloids such as starch and gelatin, ethylenediaminetetraacetic acid (EDTA), and talc to the mixer. In addition to the above, it is conventionally known to use diatomaceous earth, silica, clay, bentonite, acid clay, talc, etc. as pitch removers by adding them to pulp raw materials or white water systems. None of the pitch removers mentioned above is a decisive factor in pitch control, and in response to the increase in pitch due to the deterioration of raw material quality in recent years, various methods such as pulp and waste paper pulp manufacturing processes, paper manufacturing processes, white water treatment processes, etc. It has not yet become an effective pitch control agent capable of adsorbing even ionic pitch in certain locations. The present inventors previously proposed a new pitch control agent and pitch control method in JP-A-1-104892. This pitch control agent is a secondary aggregate of reaction between acid-treated acid clay and aluminum salt, and has physical properties such as an oil absorption of 70 ml/100 g or more and a specific surface area of 130 m ² /g or more. . This pitch control agent is made of acid-treated acid clay treated with aluminum salt, so it strengthens the attraction of charged pitch particles in water and uses a large specific surface area to enhance the pitch control effect. However, this pitch control agent is not effective against all pitches present in the pulp and paper manufacturing processes, and its effectiveness reaches a plateau even if it is added beyond a certain level.For example, when added to white water, the pitch removal rate is generally low. It is difficult to increase the ratio to about 50% or more. [Problem to be solved by the invention] In light of the above-mentioned current situation, in a situation where the quality of raw materials is decreasing, the amount of used paper is increasing, and the amount of waste paper is increasing, it is difficult to use it in any place such as pulp manufacturing process or finger manufacturing process. There has been a need for a pitch control agent that is effective against various pitches even when the pitch is removed, and has a higher pitch removal rate than conventional pitch control agents. [Means for Solving the Problems] The present invention provides a secondary reaction aggregate of an acid-treated acid clay and an aluminum salt, and has an oil absorption of 80%.
ml/100g or more, a specific surface area of 130m ² /g or more, and an average particle size of 2.7μ or more and talc with an average particle size of 5μm or less in a weight ratio of 1:3.
This pitch control agent is characterized by being mixed at a ratio of 3:1 to 3:1. Although it is not clear why the pitch control agent of the present invention is so effective, the following reasons may be considered. That is, there are several types of pitches, and they also differ in size, and it is thought that depending on the type of pitch control agent, there is selectivity in adsorption to pitches. It is thought that there is a difference in the type of pitch adsorbed between the secondary aggregates of the reaction between acid-treated acid clay and aluminum salt and talc. Therefore, when the pitch control agent of the present invention is used, each pitch control agent shares adsorption of pitches having different properties, and it is considered that more pitches are controlled. The pitch control agent of the present invention is a mixture of reaction secondary aggregates and talc, but the mixing ratio may be such that the reaction secondary aggregates cannot be used alone even if the reaction secondary aggregates are too much or too little. In comparison, no significant pitch effect is obtained, and the mixing ratio of talc in the reaction secondary agglomerates is required to be from 3:1 to 1:3 by weight. According to experiments conducted by the present inventors, it has been confirmed that the highest pitch removal rate can be obtained when the mixing ratio is 1:1. Since the pitch control agent of the present invention efficiently adsorbs and removes pitches having various properties as described above, it can be effectively used in all parts of the pulp manufacturing process and paper manufacturing process. When it is added to the stock in the pulp manufacturing process or paper manufacturing process, a preferable pitch removal effect can be obtained by using it in an amount of 0.5 to 3% by weight based on the pulp (solid content). On the other hand, as the present applicant has already proposed in JP-A-1-104892, pitch control agents are more likely to accumulate pitch through circulation than when added to pulp or stock in the papermaking process, which has relatively little pitch. Adding it to the white water that circulates through the pulp manufacturing process, used paper pulp manufacturing process, and paper manufacturing process allows for the removal of various pitches with different properties in a small amount and efficiently. Examples of where to add the pitch control agent to white water in each process and how to use the white water include adding the pitch control agent of the present invention to high-concentration white water obtained from paper stock recovery equipment for white water in the papermaking process, and adding the pitch control agent of the present invention to beaten pulp. The pitch control agent of the present invention is added to the recycled white water of the pulp manufacturing process and the recycled white water of waste paper in the waste paper processing process. In addition, the pitch control agent of the present invention is added to the dilution prior to flotation in the waste paper deinking process, and the white water generated in the final deinking process is used. The pitch control method using the pitch control agent of the present invention can achieve remarkable effects in controlling pitch spots on paper and pitch trouble in each process by performing these methods in parallel at two or more locations. The amount of the mixture of the acid-treated acid clay (activated clay) and the aluminum salt, which is the pitch control agent of the present invention, and the mixture of talc and the white water in each of the above steps is determined by the white water solid content (pulp ), a sufficient effect is exhibited at 0.1 to 3% by weight. In reality, the amount added varies depending on the process, for example, 0.1 to 0.5% by weight in the pulp process and 0.2% in the waste paper processing process.
A preferable removal effect is obtained at ~1% by weight. In addition, when the pitch control agent of the present invention is applied to white water, it is added in an amount of 0.1 to 3% by weight based on the paper stock content in the white water, so the amount used is as follows: 0.014~ for the fiber content of pulp or paper stock when used as 15%
The amount is 0.45% by weight, and the pitch control effect can be achieved with about 1/10 of the amount of pitch control agent added to ordinary pulp raw materials. By the way, the present invention was filed by the applicant in patent application No.
This is also an improvement over the pitch control agent proposed in the application No. 256382, and the average particle size of the secondary aggregates is increased compared to this prior invention, so the pitch removal rate is slightly lower. It has the effect of improving the fixation rate on paper while keeping it at about the same level, and also improving the opacity when it is incorporated into paper. [Example] Next, the present invention will be explained in more detail with reference to Examples. The test methods for Examples and Comparative Examples are as follows. Colloidal pitch number Hemastometer with scale of 50μm and size 22mm
Cover with a 30 mm cover glass, pour this white water through a capillary tube from one end, and use a microscope.
The number of colloidal pits was counted at 800x magnification. Divide this count number by the number of squares counted to obtain the average number of colloidal pitches per square, and use the following formula to calculate the number of colloidal pitches per ^cm3 (P).
was calculated. P=PC×d/V PC: Average number of colloidal pits per square d: Depth correction coefficient = 1.1 V: Volume of liquid above the square The volume of liquid above the square is 0.1 mm in depth and base area.
Since it is 2500 μm ² , converted to cm ³ P = 1.1 × PC / 2.5 × 10 ^-7 = PC × 4.4 × 10 ⁶ pitch area Measure pitch area according to JIS P8208 Example 1 Preparation of pitch control agent Oil absorption 75 ml /100g, specific surface area 100cm ² /g 4.5Kg of activated clay was weighed out, and 25.5Kg of water was added to make the concentration 15.
A weight percent slurry was obtained. An aqueous aluminum chloride solution (Al ₂ O ₃ content 10
%), 1.44 kg (as solid content) was added, stirred and reacted for 1 hour, then dried and heat treated in a blow dryer at a temperature of 130° C. for 4 hours, and allowed to cool. This reaction product was pulverized to obtain a secondary reaction aggregate (A). The oil absorption amount of this reaction secondary aggregate (A) was 110 ml/100 g, the specific surface area by BET method was 170 m ² /g, and the average particle size was 2.7 μm. Next, talc with an average particle size of 4 μm (oil absorption 43 ml/
(100 g, specific surface area 16 m ² /g) was prepared. The pitch control agent of the present invention is a mixture of a reaction secondary aggregate and talc in a predetermined ratio as shown in Table 1. The unbleached kraft pulp (contains 70% domestic softwood and 30% tropical hardwood) before the pulp bleaching process shown in the drawing is washed with a washing machine, dust removed with a screen, sorted, and dehydrated with a dehydrator. In the white water bit with a concentration of 0.02%,
White water to which the mixture of the reaction secondary aggregate (A) of the present invention and talc is added in the amount shown in Table 1 per ton of pulp,
The number of colloidal pitches of the pulp at the outlet of the dehydrator after being used to dilute the pulp raw material in the screen and dehydrator was measured. Example 2 In Example 1, instead of the reaction secondary aggregate (A), the reaction secondary aggregate was crushed for a shorter time to have an average particle size of 3.2 μm, an oil absorption of 80 ml/g, and a specific surface area of 130
The reaction was carried out in exactly the same manner as in Example 1 except that the reaction secondary aggregate (B) was used at ml/g. Comparative Example 1 The same procedure as in Example 1 was conducted except that talc was added in the amount shown in the table instead of the mixture of the secondary reaction aggregate (A) and talc. Comparative Example 2 The same procedure as in Example 1 was carried out except that the mixture of the secondary reaction aggregate (A) and talc was not added. Reference Example 1 Example 1 was carried out in exactly the same manner as in Example 1, except that only the reaction secondary aggregate (A) was added instead of the mixture of the reaction secondary aggregate (A) and talc. Reference Example 2 Example 2 was carried out in exactly the same manner as in Example 2, except that only the reaction secondary aggregate (B) was added instead of the mixture of the reaction secondary aggregate (B) and talc. The test results of Examples 1 and 2, Comparative Examples 1 and 2, and Reference Examples 1 and 2 are shown in Table 1.

[Table] According to the results in Table 1, the pitch control agent of the present invention has a mixing ratio of reaction secondary aggregate (A) and talc of 3:1 (Example 1-2) to 1:3 (Example 1-2). 1-
In the range of 3), the pitch removal effect is improved compared to the case where the reaction secondary aggregate (A) is used alone (Reference Example 1). In particular, the pitch removal rate was highest when the mixing ratio of the reaction secondary aggregate (A) and talc was 1:1 (Example 1-1). In addition, the reaction secondary aggregate (B) of Example 2 (oil absorption 80
ml/g) with talc at a ratio of 1:1, the pitch removal rate is lower than in Example 1-1, but the reaction 2
The pitch removal rate is much improved compared to using the secondary aggregate (B) alone (Reference Example 2). Examples 3 and 4 A pitch control agent of the present invention, which is a 1:1 mixture of the reaction secondary aggregate (A) obtained in Example 1 and talc, was prepared. Next, tropical hardwood chemical pulp, softwood chemical pulp, softwood mechanical pulp, and deinked waste paper pulp are classified by weight.
Mix in a ratio of 25:15:40:20, and then add 5 kg of rosin sizing agent/t of pulp and 20 kg of sulfuric acid/t of pulp.
were added and mixed to prepare a pulp slurry having a concentration of 3% by weight. To this pulp slurry, a 1:1 mixture of the reaction secondary aggregate (A) and talc was added at 1% by weight (Example 3) and 0.5% by weight based on the pulp solid content.
(Example 4) Added and stirred for 5 minutes. The effect of removing pitch by adding this pitch control agent was evaluated by the following test method. The results are shown in Table 2. Comparative Example 3 In Example 3, talc (oil absorption 40 ml/100 g, specific surface area 10
The pitch area was measured in the same manner as in Example 3, except that the pitch area was measured using the following formula: (m ² /g). Comparative Example 4 In Example 3, commercially available talc-based pitch control agent A (hereinafter abbreviated as commercial product A) (oil absorption 47 ml/100 g, specific surface area 16 m ² /g) was used instead of the reaction secondary aggregate of the present invention. Except for this, the pitch area was measured in the same manner as in Example 3. Comparative Example 5 In Example 3, pitch area was determined in exactly the same manner as in Example 3, except that activated clay (oil absorption 80 ml/100 g, specific surface area 110 m ² /g) was used instead of the reaction secondary aggregate of the present invention. was measured. Comparative Example 6 In Example 3, the pitch area was measured in exactly the same manner as in Example 3, except that 0.3% of the reaction secondary aggregate of the present invention was added to the pulp solid content. Comparative Example 7 In Example 3, the pitch area was measured in exactly the same manner as in Example 3, except that the reaction secondary aggregate of the present invention was not added. The test results of Examples 3 and 4 and Comparative Examples 3 to 7 are
Shown in the table.

〔Effect of the invention〕

As detailed above, the pitch control agent of the present invention was invented in response to the increase in pitch caused by the deterioration of raw material quality in recent years, such as the increase in the use of tropical hardwoods that have a lot of pitch or the increase in the use of waste paper pulp. The pitch control agent of the present invention is composed of a reaction secondary aggregate of an acid-treated acid clay and an aluminum salt, especially a mixture of a reaction secondary aggregate with a large oil absorption and specific surface area, and talc, and is better than conventional pitch control agents. It has extremely excellent pitch adsorption performance. The pitch control agent of the present invention is effective in removing pitch when added to ordinary pulp or paper stock, and can also be used to circulate and reuse white water in the manufacturing process of pulp, deinked waste paper pulp, and white water treatment in the paper manufacturing process. By adding this to talc, the reaction secondary aggregates and talc each absorb pitches of different properties in the acid clay that increase during the circulation of white water caused by pulp, and exhibit a synergistic effect, resulting in a synergistic effect. The pitch concentration during the manufacturing process and papermaking process can be significantly reduced, and the quality of the resulting pulp and paper can be improved by removing pitch to a greater extent than when using conventional pitch control agents. Therefore, the present invention is an unprecedented pitch control agent that can significantly reduce pitch troubles in pulp and paper mills.

[Brief explanation of the drawing]

The drawing is a schematic diagram showing the flow of the pulp manufacturing process (bleached kraft pulp).

Claims (1)

[Claims] 1 A secondary reaction aggregate of acid-treated acid clay and aluminum salt, and has an oil absorption of 80ml/
A weight ratio of 1:3 to 3:1 of the reaction secondary aggregate having a specific surface area of 100 g or more, a specific surface area of 130 m ² /g or more, and an average particle size of 2.7 μm or more and talc having an average particle size of 5 μm or less. A pitch control agent characterized by being mixed with.