Pitch controlling agent

Abstract

To provide a new pitch controlling agent that can achieve a sufficient pitch controlling effect in a manufacturing process for kraft pulp.SOLUTION: The present disclosure, as one aspect, relates to a pitch controlling agent in a manufacturing process for kraft pulp, which contains, as an active ingredient, a copolymer of a cationic monomer represented by the following formula (1) and a monomer represented by the following formula (2).SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a pitch control agent, a pitch control method, and a paper manufacturing method using them.

Background Art

[0002] Conventionally, in the papermaking process, problems have arisen due to pitch-related obstacles. To suppress and / or prevent this, various chemicals have been developed. Pitch refers to a water-insoluble sticky substance mainly composed of organic substances derived from natural resins, gum substances released from wood, pulp, paper, etc., and additives used in the manufacturing process of paper and pulp.

[0003] Pitch is usually dispersed in a colloidal state in process water (e.g., pulp slurry, white water, etc.) in the production of paper and pulp. However, when pitch aggregates and grows due to some external action, it adheres to manufacturing equipment such as fan pumps, inside pipes, chests, wires, felts, and rolls, causing dirt and a decrease in workability. In addition, pitch that adheres to the manufacturing equipment and further grows adheres to paper or pulp, causing dirt spots and / or defects and paper breaks, resulting in a decrease in product quality and productivity.

[0004] As countermeasures against such pitch problems, various methods have been proposed, such as a method of bringing a chemical (external addition type pitch control agent) into contact with manufacturing equipment, and a method of adding a chemical (internal addition type pitch control agent) to a pulp slurry. Patent Document 1 discloses a method of adding an anionic chelating agent having a molecular weight of less than 1000 to a pulp slurry and then adding a cationic polymer of a polyaminoamide type or a polyallylamine type. Patent Document 2 discloses a pitch inhibitor for a paper and pulp manufacturing process containing, as active ingredients, a nonionic surfactant, a phosphonic acid compound, an organic sulfonic acid compound, and a cationic polymer such as an allyldialkylammonium chloride-acrylamide copolymer. Patent Document 3 discloses a method of adding a copolymer composed of a cationic monomer and acrylamide to a papermaking raw material mainly composed of mechanical pulp in a papermaking process.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] The papermaking process generally includes a pulping process for obtaining a pulp raw material from raw materials such as wood and waste paper, a paper stock preparation process for performing mechanical treatment, addition of chemicals, etc. on the pulp raw material obtained in the pulping process, and a papermaking process for forming a sheet of pulp. The pulping process (pulp manufacturing process) using wood as a raw material is roughly classified into a method of chemically extracting pulp using chemicals (chemical pulp) and a method of mechanically grinding wood to obtain pulp (mechanical pulp). In the pulping process (pulp manufacturing process) of kraft pulp, which is a type of chemical pulp, usually, a cooking process, a screening and washing process, an oxygen delignification process, and a bleaching process are carried out in this order. That is, first, wood chips are cooked with a mixed solution of caustic soda and sodium sulfide to dissolve the resin (lignin) in the chips and extract the fiber component (pulp). After that, the pulp and lignin are separated, and foreign substances in the separated pulp are screened and washed. Then, the washed pulp is treated with oxygen and alkali to remove (decompose) the resin (lignin), and finally, the pulp is bleached with chemicals.

[0007] Since the cooking process in the kraft pulp manufacturing process is carried out under high temperature and high pressure in the presence of an alkaline agent, a high-temperature and high-alkali pulp slurry is discharged. The temperature and pH of this pulp slurry can change during the process of passing through the unbleached pulp washing process, oxygen delignification process, and bleaching process, etc.

[0008] In the papermaking process, it is considered that the cause of pitch agglomeration and coarsening is due to changes in the water environment such as pulp slurry, for example, pH, temperature, and electrical conductivity. Therefore, in the kraft pulp manufacturing process where the water environment changes drastically, there is a problem that a sufficient pitch control effect cannot be obtained by the conventional method.

[0009] The present disclosure provides a new pitch control agent and a pitch control method capable of obtaining a sufficient pitch control effect even under high pH conditions in the kraft pulp manufacturing process.

Means for Solving the Problems

[0010] In one aspect, the present disclosure relates to a pitch control agent in a kraft pulp manufacturing process, which contains a copolymer of a cationic monomer represented by the following formula (1) and a monomer represented by the following formula (2) as an active ingredient.

Chemical formula

[0011] In other aspects, the present disclosure relates to a pitch control method in a kraft pulp manufacturing process, which includes adding a copolymer of a cationic monomer represented by the following formula (1) and a monomer represented by the following formula (2).

Chemical formula

Advantages of the Invention

[0012] According to the present disclosure, a new pitch control agent capable of obtaining a sufficient pitch control effect in the kraft pulp manufacturing process, and a pitch control method can be provided.

Modes for Carrying Out the Invention

[0013] The present disclosure is based on the finding that N-benzyl-2-(methacryloyloxy)-N,N-dimethylethanaminium chloride·acrylamide copolymer and [2-(methacryloyloxy)ethyl](trimethyl)ammonium chloride·styrene polymer exhibit very high pitch dispersibility in a high-temperature and high-alkali pulp slurry where a sufficient pitch control effect could not be obtained with conventional pitch control agents. Further, the above polymers exhibit excellent pitch dispersibility not only in high-temperature and high-alkali pulp slurries but also in medium-temperature and high-alkali pulp slurries, and have excellent pitch dispersibility even when the pH of the pulp slurry varies greatly. Therefore, according to the present disclosure, in the kraft pulp manufacturing process, excellent pitch dispersibility can be achieved, and a high pitch control effect can be obtained.

[0014] The "kraft pulp" in the present disclosure refers to pulp manufactured by the kraft process. The kraft process generally refers to a method of pulping wood by boiling wood chips at a high temperature (150°C to 190°C) in a cooking liquor mainly composed of sodium hydroxide and sodium sulfide. In the present disclosure, the "kraft pulp manufacturing process" refers to the process of pulping wood by the kraft method to produce kraft pulp, and may include all processes included in the so-called pulping process. In one or more embodiments, it may include a cooking process, a washing process (screening and washing process), an oxygen delignification process, a bleaching process, and the like. The pitch control agent and the pitch control method of the present disclosure can exhibit an excellent pitch control effect particularly in the pulping process of kraft pulp. Therefore, in one or more embodiments, the kraft pulp manufacturing process in the present disclosure only needs to include at least the pulping process, and may not include processes performed after the pulping process, such as a paper stock preparation process and a papermaking process for forming the pulp into a sheet.

[0015] In one or more embodiments, "having excellent pitch dispersibility" in the present disclosure means that resins and / or pitch causing pitch can be stably dispersed in a fine state in the pulp slurry, and more preferably, resins and / or pitch can be uniformly fixed to the pulp in a fine state.

[0016] [Pitch control agent] In one aspect, the present disclosure relates to a pitch control agent in a kraft pulp manufacturing process. The pitch control agent of the present disclosure contains a copolymer (copolymer A) of a cationic monomer (monomer (1)) represented by the following formula (1) and a monomer (monomer (2)) represented by the following formula (2) as an active ingredient. [Chemical formula] In formula (1), R 1 is a hydrogen atom or a methyl group, R 2 and R 3 are each independently a methyl group or an ethyl group, A is a methylene group or an ethylene group, R 4 is a hydrogen atom or a phenyl group, X 1- is an anion. In formula (2), R 5 is a hydrogen atom or a methyl group, R6 is an amide group or a phenyl group, and R 4 and R 6 One of them is a phenyl group. * in the above formulas (1) and (2) represents a bond.

[0017] In one or more embodiments of the present disclosure, the above polymer is a copolymer composed of the cationic monomer represented by the above formula (1) and the monomer represented by the above formula (2).

[0018] In one or more embodiments of formula (1), R 1 is a methyl group, and / or R 2 is a methyl group, and / or R 3 is a methyl group, and / or A is a methylene group, and / or R 4 is a hydrogen atom or a phenyl group. X 1- is an anion, and as the anion, in one or more embodiments, it is a halide ion, preferably a chloride ion.

[0019] Examples of the monomer (1) include, in one or more embodiments, (meth)acryloyloxyethyltrimethylammonium chloride, (meth)acryloyloxyethyltriethylammonium chloride, (meth)acryloyloxyethyldimethylbenzylammonium chloride, and (meth)acryloyloxyethyldiethylbenzylammonium chloride.

[0020] In one or more embodiments of formula (2), R 5 is a hydrogen atom, and / or R 6 is an amide group or a phenyl group.

[0021] Examples of the monomer (2) include, in one or more embodiments, (meth)acrylamide, and styrene.

[0022] As combinations of monomer (1) and monomer (2), in one or more embodiments, combinations such as (meth)acryloyloxyethyltrimethylammonium chloride and styrene, (meth)acryloyloxyethyltriethylammonium chloride and styrene, (meth)acryloyloxyethyldimethylbenzylammonium chloride and (meth)acrylamide, and (meth)acryloyloxyethyldiethylbenzylammonium chloride and (meth)acrylamide can be mentioned. From the point of further improving the pitch control effect, combinations of (meth)acryloyloxyethyltrimethylammonium chloride and styrene, and (meth)acryloyloxyethyldimethylbenzylammonium chloride and (meth)acrylamide are preferable.

[0023] In one or more embodiments, the proportion (mol%) of monomer (1) in copolymer A is 5 mol% or more and 95 mol% or less. In one or more embodiments, the proportion (mol%) of monomer (2) in copolymer A is 5 mol% or more and 95 mol% or less.

[0024] In one or more embodiments, the arrangement of monomers (1) and (2) in copolymer A may be random or block.

[0025] In one or more embodiments, the mass average molecular weight of copolymer A is 10,000 or more. In one or more embodiments, from the point of further improving the pitch control effect, the mass average molecular weight of the copolymer of the cationic monomer represented by formula (1) (preferably (meth)acryloyloxyethyldimethylbenzylammonium chloride) and (meth)acrylamide is 500,000 or more. In one or more embodiments, the mass average molecular weight of the copolymer of the cationic monomer represented by the formula (1) (preferably, (meth)acryloyloxyethyltrimethylammonium chloride) and styrene is 10,000 or more, 20,000 or more, 30,000 or more, or 50,000 or more from the viewpoint of further improving the pitch control effect, and is less than 1,000,000, 900,000 or less, or 800,000 or less from the same viewpoint.

[0026] In one or more embodiments, the cation equivalent in the molecule of copolymer A is 1.0 meq / g to 5.0 meq / g, and preferably 2.6 meq / g to 3.9 meq / g or 2.6 meq / g to 3.8 meq / g from the viewpoint of further improving the pitch control effect.

[0027] In one or more embodiments, examples of copolymer A include copolymer A1 (N-benzyl-2-(methacryloyloxy)-N,N-dimethylethanaminium chloride·acrylamide copolymer) and copolymer A2 ([2-(methacryloyloxy)ethyl](trimethyl)ammonium chloride·styrene polymer) represented by the following formula. [Chemical formula] In the above formula, k, l, k', and l' are molar fractions, each indicating 5 mol% to 95 mol%.

[0028] In one or more embodiments, the monomer sequences in copolymers A1 and A2 may be random or block. In one or more embodiments, the mass average molecular weight of copolymer A1 is 10,000 or more, 10,000 or more, 20,000 or more, 30,000 or more, or 50,000 or more from the viewpoint of further improving the pitch control effect, and is less than 1,000,000, 900,000 or less, or 800,000 or less from the same viewpoint. The weight average molecular weight of the copolymer A2 is 10,000 or more in one or more embodiments, and 500,000 or more from the viewpoint of further improving the pitch control effect.

[0029] The cation equivalent in the molecule of the copolymer A1 is 1.0 meq / g to 5.0 meq / g in one or more embodiments, 2.6 meq / g or more, 2.7 meq / g or more, 2.8 meq / g or more, 2.9 meq / g or more, 3.0 meq / g or more, or 3.1 meq / g or more from the viewpoint of further improving the pitch control effect, and 3.9 meq / g or less, or 3.8 meq / g or less is preferable from the same viewpoint. The cation equivalent in the molecule of the copolymer A2 is 1.0 meq / g to 5.0 meq / g in one or more embodiments, 2.6 meq / g or more, or 2.7 meq / g or more from the viewpoint of further improving the pitch control effect, and 3.9 meq / g or less, 3.5 meq / g or less, or 3.0 meq / g or less is preferable from the same viewpoint.

[0030] In one or more embodiments, the copolymer A can be produced by copolymerizing a monomer mixture composed of the cationic monomer represented by the above formula (1) and the monomer represented by the above formula (2).

[0031] The content of the copolymer A in the pitch control agent of the present disclosure is 0.5% by weight or more, or 1% to 50% by weight in one or more embodiments.

[0032] From the viewpoint of further improving the pitch control effect, the pitch control agent of the present disclosure may further contain a diallyldialkylammonium salt·(meth)acrylamide copolymer (copolymer B) as an active ingredient in one or more embodiments. Examples of the diallyldialkylammonium salt·(meth)acrylamide copolymer include the copolymer (copolymer B) represented by the following formula (3) in one or more embodiments.

Chemical formula

[0033] In formula (3), m represents the content of the cationic monomer (mol% based on the total amount of monomers), and n represents the content of the (meth)acrylamide monomer (mol% based on the total amount of monomers). The content ratio (m:n) of the cationic monomer to the (meth)acrylamide monomer is 1:1 to 2:1 in one or more embodiments where it is not particularly limited.

[0034] In formula (3), in one or more embodiments, R 7 is a methyl group, and / or, R 8 is a methyl group, R 9 is a hydrogen atom, and X 2- is an anion. As the anion, in one or more embodiments, it is a halide ion, preferably a chloride ion.

[0035] Examples of the cationic monomer in formula (3) include dialyldimethylammonium halides such as dialyldimethylammonium chloride (DADMAC) in one or more embodiments.

[0036] Examples of the (meth)acrylamide monomer in formula (3) include (meth)acrylamide in one or more embodiments.

[0037] Examples of copolymer B include a copolymer of dialyldimethylammonium chloride and (meth)acrylamide in one or more embodiments.

[0038] In one or more embodiments, the monomer sequence in copolymer B may be random or block.

[0039] In one or more embodiments, the weight average molecular weight of copolymer B is 10,000 or more, preferably 50,000 or more, or 100,000 or more, more preferably 100,000 to 500,000, from the viewpoint of further improving the pitch control effect.

[0040] In one or more embodiments, the content of copolymer B in the pitch control agent of the present disclosure is 0.5% by weight or more, or 1% to 50% by weight.

[0041] In one or more embodiments, the pitch control agent of the present disclosure may be in the form of a solution containing the above copolymer A (and copolymer B as required).

[0042] In one or more embodiments, the pitch control agent of the present disclosure may contain other components as long as it does not inhibit the pitch control effect of the above copolymer. Examples of other components include any components such as pH adjusters, surfactants, viscosity adjusters, rust inhibitors, antioxidants, antistatic agents, preservatives, and defoamers in one or more embodiments.

[0043] [Pitch Control Method] In one aspect, the present disclosure relates to a pitch control method including adding a copolymer of a cationic monomer represented by the following formula (1) and a monomer represented by the following formula (2) in a kraft pulp manufacturing process. [Chemical Formula]

[0044] The copolymer A, formulas (1) and (2) are the same as the pitch control agent of the present disclosure. The pitch control method of the present disclosure can suppress pitch trouble by adding a copolymer (copolymer A) of a cationic monomer represented by the above formula (1) and a monomer represented by formula (2) to the pulp slurry in the kraft pulp manufacturing process. In one or more embodiments, the pitch control agent of the present disclosure may be used as the copolymer A (and copolymer B described later).

[0045] The addition amount of the copolymer A can be appropriately determined. In one or more embodiments, it is 0.001 to 5 parts by weight, or 0.005 to 3 parts by weight, based on 100 parts by weight of the pulp solids. In one or more embodiments where the addition amount of the copolymer A is not particularly limited, it may be 0.01 part by weight or more, 0.1 part by weight or more, or 1 part by weight or more.

[0046] In order to further improve the pitch control effect, the pitch control method of the present disclosure may further include adding the above diallyldialkylammonium salt·(meth)acrylamide copolymer (copolymer B) in one or more embodiments.

[0047] The addition amount of the copolymer B can be appropriately determined. In one or more embodiments, it is 0.0001 to 5 parts by weight, or 0.0005 to 1 part by weight, based on 100 parts by weight of the pulp solids. In one or more embodiments where the addition amount of the copolymer B is not particularly limited, it may be 1 part by weight or less, 0.1 part by weight or less, or 0.01 part by weight or less.

[0048] When the copolymer A and the copolymer B are used in combination in the pitch control method of the present disclosure, the ratio (weight ratio, copolymer A:copolymer B) of the copolymer A to the copolymer B is 1:0.01 to 1:10, or 1:0.1 to 1:5 in one or more embodiments.

[0049] The copolymer A (and optionally copolymer B) used in the pitch control method of the present disclosure can obtain an excellent pitch control effect even in a high-temperature and highly alkaline pulp slurry. Therefore, in one or more embodiments, the copolymer A (or the pitch control agent of the present disclosure) may be added to the pulp slurry or to the raw material chips. In one or more embodiments, the pulp slurry in the kraft pulp manufacturing process (for example, the pulp slurry in the digestion process) is a strong alkali with a pH of 9 or higher. In one or more embodiments, the pH of the pulp slurry is 10 or higher, 11 or higher, or 12 or higher. In one or more embodiments, the pH of the pulp slurry is 13 or lower. In one or more embodiments, the pitch control method of the present disclosure may include adding copolymer A (or copolymers A and B) to the pulp slurry. From the point of obtaining an excellent pitch control effect, it may include adding copolymer A (or copolymers A and B) to a pulp slurry with a pH of 9 or higher. Examples of the pulp slurry with a pH of 9 or higher include, in one or more embodiments, the pulp slurry discharged from the digester in the digestion process.

[0050] In the processes from the upstream side to the downstream side of the pulping process of kraft pulp, the dispersibility of pitch may decrease and the pitch may coarsen due to the change in the pH of the pulp slurry to neutral or acidic or the decrease in temperature. On the other hand, the copolymer A used in the pitch control method of the present disclosure can obtain a sufficient pitch control effect not only in a high-temperature and highly alkaline pulp slurry but also in a medium-temperature and highly alkaline and / or high-temperature acidic to alkaline pulp slurry. Therefore, according to the pitch control method of the present disclosure, a sufficient pitch control effect can be achieved even in the downstream process of the pulping process. Further, the copolymer A (or the pitch control agent of the present disclosure) added to the pulp slurry in the upstream side (for example, the digestion process) of the pulping process is fixed to the pulp and sent to the downstream process together with the pulp slurry. Therefore, even when no further chemical is added on the downstream side of the addition location of the copolymer A (or the pitch control agent of the present disclosure), a pitch control effect can be obtained. From the viewpoint of obtaining a better pitch control effect, the copolymer A (or the pitch control agent of the present disclosure) may be further added to the pulp slurry in the downstream process (for example, the washing process and the bleaching process) of the pulping process. The pulp slurry in the pitch control method of the present disclosure may be a pulp slurry in which the pH varies (can vary) from a strongly alkaline state of pH 9 or higher to 8.5 or lower in one or more embodiments.

[0051] In the pitch control method of the present disclosure, the addition location of the copolymer (the pitch control agent of the present disclosure) is not particularly limited, and in one or more embodiments, it may be added at the location where pitch trouble occurs or upstream thereof. Since the copolymer A used in the pitch control method of the present disclosure can obtain an excellent pitch control effect even in a high-temperature and highly alkaline pulp slurry, in one or more embodiments where it is not particularly limited, examples of the addition location include the blow tank in the digestion process and / or upstream thereof (between the digester and the blow tank).

[0052] [Method for producing kraft pulp] The present disclosure relates to, among other aspects, a method for producing kraft pulp including performing pitch control by the pitch control method of the present disclosure in the pulping process of kraft pulp. The present disclosure relates to, among other aspects, a method for producing kraft pulp including a pulping process of kraft pulp and performing pitch control by the pitch control method of the present disclosure. Also, the present disclosure relates to, among other aspects, a method for producing kraft pulp including adding the pitch control agent of the present disclosure in the pulping process of kraft pulp. Also, the present disclosure relates to, among other aspects, a method for producing kraft pulp including performing pitch control with the pitch control agent of the present disclosure in the pulping process of kraft pulp.

[0053] The present disclosure further relates to one or more of the following embodiments. [1] A pitch control agent in a kraft pulp manufacturing process, A pitch control agent containing, as an active ingredient, a copolymer of a cationic monomer represented by the following formula (1) and a monomer represented by the following formula (2). [Chemical formula] In formula (1), R 1 is a hydrogen atom or a methyl group, R 2 and R 3 are each independently a methyl group or an ethyl group, A is a methylene group or an ethylene group, R 4 is a hydrogen atom or a phenyl group, X 1- is an anion, In formula (2), R 5 is a hydrogen atom or a methyl group, R 6 is an amide group or a phenyl group, R 4 and R 6 One of them is a phenyl group. [2] The pitch control agent according to [1], further containing a diallyldialkylammonium salt-(meth)acrylamide copolymer as an active ingredient. [3] A pitch control method including adding a copolymer of a cationic monomer represented by the following formula (1) and a monomer represented by the following formula (2) in a kraft pulp manufacturing process.

Chemical formula

[0054] Hereinafter, the present disclosure will be described in more detail using examples, comparative examples, and reference examples. However, these are illustrative and the present disclosure is not limited to these examples.

Examples

[0055] In the following examples and comparative examples, the following agents were used.

Table 1

[0056] [Adhesion Inhibition Confirmation Test 1] (1) A polypropylene film (13 cm × 30 cm) was prepared. The PP film was washed with hot water at 90 °C for 1 minute to remove the plasticizer, and then dried. The weight after drying was weighed with an electronic balance to 0.1 mg. (2) 90 g of filter paper was immersed in 2910 g of tap water for 20 minutes, and then disintegrated at 2500 rpm for 20 minutes using a disintegrator to prepare a pulp slurry (pulp solid content concentration: 1%). (3) 1 kg of the pulp slurry prepared in (2) was weighed, 2 kg of tap water was added, and then the pH was adjusted to 12.5 using calcium hydroxide. (4) The pulp slurry obtained in (3) was weighed 500 g into a 1 L plastic beaker while stirring well with a ladle, and then poured into another 1 L beaker. (5) A six - stirrer with a water bath was heated to 80 °C, the 1 L beaker in (4) was set on it, and strongly stirred with a 50 mm cross stirrer. (6) When the temperature of the pulp slurry in the 1 L beaker reached the set temperature (80 °C), the agents shown in Table 2 below (except for microtalc and HPMC) were added at 0.5 g. For microtalc and HPMC, 5 g of a 10% water suspension was added. A baffle with the PP film prepared in (1) made into a cylinder was put into the above beaker to which the agents were added. After 5 minutes, 1.67 g of a 30% simulated pitch solution was added and stirred for 1 hour. For agents other than microtalc and HPMC, the weights (g) shown in Table 2 below were weighed, water was added to make 100 g to prepare an agent solution, and 0.5 g of it was added. The simulated pitch solution was prepared by dissolving plant-derived oils and fats (8 types) in ethanol and coloring it red with Sudan IV (chemical name, 1-[[2-methyl-4-[(2-methylphenyl)azo]phenyl]azo-2-naphthalenol). (7) After stirring for 1 hour, the baffle was taken out of the beaker, and the pulp fibers adhering to the baffle were removed with running water and dried thoroughly at room temperature. (8) The weight after drying was weighed to 0.1 mg with an electronic balance to determine the adhesion amount of the simulated pitch. (9) Taking the adhesion amount of the blank (BL) as 100%, the adhesion prevention rate was calculated from the following formula. The results are shown in Table 2 below. Adhesion prevention rate = {(Adhesion amount of BL) - (Adhesion amount with chemical addition)} / (Adhesion amount of BL) × 100

Table 2

[0057] In Examples 1 to 5 using the copolymer of the cationic monomer represented by Formula (1) and the monomer represented by Formula (2), under the conditions of high temperature and high alkalinity of pH 12.5 and 80 °C, compared with the comparative example, a state where the pitch was finely dispersed was maintained and high dispersibility was shown. As shown in Table 2, the adhesion to the PP film was significantly suppressed. This can be said to be due to the decrease in the adhesiveness of the resin surface that causes pitch and the suppression of the coarsening of the resin. Therefore, it can be said that the copolymer of the cationic monomer represented by Formula (1) and the monomer represented by Formula (2) is excellent in heat resistance and alkali resistance and has an excellent effect of incorporating the pitch component in a fine shape into the paper.

[0058] [Adhesion Suppression Confirmation Test 2] In (6), except that the set temperature was 60 °C and the chemicals shown in Table 3 below were used, it was carried out in the same manner as [Adhesion Suppression Confirmation Test 1]. The results are shown in Table 3 below.

[0059] [Adhesion Suppression Confirmation Test 4] Except that the pH in (3) was adjusted to pH 7 and the set temperature in (6) was set to 40°C, the test was conducted in the same manner as [Adhesion Inhibition Confirmation Test 2]. The results are shown in Table 3 below.

[0060]

Table 3

[0061] In addition to the conditions of high temperature and high alkali (pH 12.5, 80°C), as shown in Table 3 above, the pitch control agent of the present disclosure exhibits high dispersibility and adhesion inhibition effect even under the conditions of medium temperature and high alkali (pH 12.5, 60°C), and also exhibits good pitch dispersibility and adhesion inhibition effect under the condition of pH 7. In particular, Example 7 in which DMAEM quaternary compound / AAm and DADMAC / AAm1 were used in combination showed very high pitch dispersibility and adhesion inhibition effect under any pH and temperature conditions. Also, by using DMAEM quaternary compound / AAm and DADMAC / AAm1 in combination, even when treated under the conditions of pH 7 and high temperature, very high pitch dispersibility and adhesion inhibition effect were shown.

Claims

1. A pitch control agent in the kraft pulp manufacturing process, The pitch control agent contains as an active ingredient a copolymer of a cationic monomer represented by the following formula (1) and a monomer represented by the following formula (2). 【Chemical 1】 In formula (1), R 1 is a hydrogen atom or a methyl group, R 2 and R 3 are each independently a methyl group or an ethyl group, A is a methylene group or an ethylene group, R 4 is a hydrogen atom or a phenyl group, X 1- is an anion, In formula (2), R 5 is a hydrogen atom or a methyl group, R 6 is an amide group or a phenyl group, R 4 and R 6 One of them is a phenyl group.

2. Furthermore, the pitch control agent according to claim 1, which contains a diallyldialkylammonium salt-(meth)acrylamide copolymer as an active ingredient.

3. A pitch control method in the kraft pulp manufacturing process, which includes adding a copolymer of a cationic monomer represented by the following formula (1) and a monomer represented by the following formula (2). 【Chemical 2】 In formula (1), R 1 is a hydrogen atom or a methyl group, R 2 and R 3 are each independently a methyl group or an ethyl group, A is a methylene group or an ethylene group, R 4 is a hydrogen atom or a phenyl group, X is an anion, In formula (2), R 5 is a hydrogen atom or a methyl group, R 6 is an amide group or a phenyl group, R 4 and R 6 One of them is a phenyl group.

4. Furthermore, the pitch control method according to claim 3, which includes adding a diallyldialkylammonium salt-(meth)acrylamide copolymer.

5. The pitch control method according to claim 4, wherein the copolymer is added to the pulp slurry.

6. The pitch control method according to claim 5, wherein the pH of the pulp slurry is 9 or higher.

7. A method for manufacturing kraft pulp, The manufacturing method includes performing pitch control by the pitch control method according to any one of claims 3 to 6.

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