KR102092128B1 - Retention method for manufacturing industrial paper to improve turbidity of process white water, and retention system - Google Patents

Abstract

According to the present invention, a retention method for manufacturing industrial paper and a retention system thereof are capable of improving turbidity and having excellent effects in retention ratio and dehydration efficiency by adding a low ionic cationic polyacrylamide as a retention agent to an anionic material to pre-aggregate the same, adding a cationic polyacrylamide having higher ionic properties than the retention agent used in the pre-aggregation to the anionic material to secondarily aggregate the same, and re-aggregating (re-adsorbing) the anionic material into bentonite particles. According to the present invention, the retention method for manufacturing industrial paper comprises the following steps of: (a) primarily aggregating an anionic material by adding a first retention agent to white water dehydrated in a paper-making process and accommodating paper stock; (b) secondarily aggregating the anionic material by adding a second retention agent to the primarily aggregated white water; and (c) tertiarily aggregating and adsorbing the anionic material by adding bentonite particles to the secondarily aggregated white water, wherein the first retention agent includes a first cationic polyacrylamide, the second retention agent includes a second cationic polyacrylamide, and ionic properties of the second cationic polyacrylamide are higher than ionic properties of the first cationic polyacrylamide.

Description

Retention Method and Retention System for Manufacturing Industrial Paper for Improving Turbidity of Process White Water {RETENTION METHOD FOR MANUFACTURING INDUSTRIAL PAPER TO IMPROVE TURBIDITY OF PROCESS WHITE WATER, AND RETENTION SYSTEM}

The present invention relates to a holding method and a holding system for industrial paper production in which cationic polyacrylamide and bentonite having different ionic properties are added as a holding agent to improve the turbidity, holding and dehydration efficiency of process white water.

The manufacturing process of printing paper consists of forming, dehydrating, pressing on a paper machine (paper machine) in a state in which filler slurry is mixed with pulp slurry, the main raw material. After drying, it is completed with paper.

An important factor in the papermaking process is the stability of the paper machine. Stability of the paper machine refers to the ability to quickly recover to a normal state after passage, change of species, extraction or suspension.

Water, too, is very important. It can be said that the process is impossible without water, from the dispersion of not only water but also auxiliary ingredients to shower water in the process. Among them, the importance of the process white water (WW) is gradually increasing as the closed process of recycling in a factory circulating and recycling the generated wastewater is accelerated.

In the papermaking process, white water refers to water that is dehydrated from wet parts during pulping and papermaking processes, regardless of its color. Because white water is mostly reused in the process, the term process water is sometimes used. White water contains various materials derived from raw materials as well as fibers. For example, white water consists of ingredients from wood, recycled paper, and chemicals added in the papermaking process. White water affects not only the appearance and strength of paper, but also all processes related to fineness retention, sizing, and operability. As white water undergoes the process of recycling, its concentration becomes higher. It is practically impossible to purify all of this white water through wastewater treatment.

Therefore, it is essential to identify the components of white water and to determine the degree of contamination to establish various additives and retention systems capable of exhibiting performance in contaminated conditions.

In recent years, as the amount of phage used increases, the amount of fine fibers in the papermaking raw material increases and the use rate of calcium carbonate increases. Therefore, a retention system using a high molecular weight retention agent is required to maintain and improve the retention rate.

However, if a high molecular weight retention agent is used, excessive floc is formed, and the paper quality may be deteriorated. In addition, various chemicals such as sizing agents, starch, wetting and stamina enhancers, and fillers are added to impart the necessary properties to paper, and these chemicals can be obtained when they are settled or adsorbed on the fibers of the stock.

On the other hand, reusable microfibers or fillers in excess paper machine white water must be recovered as paper machine pulp slurry.

However, it is more important to prevent microfibers or fillers from entering the white water before this process. This is because when the white water is recycled in the process, various substances remaining in the white water interfere with the binding of the fine particles in the polymer electrolyte and the stock material, and thus act as a factor adversely affecting retention and dehydration.

In addition, 2-10 tons of water is used to produce approximately 1 ton of paper in a liner factory using recycled paper, and the degree of contamination of white water is getting worse due to the closure of white water. Accordingly, a large amount of fresh water is used for cost increase and discharge during wastewater treatment, which is economically expensive.

Therefore, in the production of paper in the paper mill of industrial paper, there is a need for research to improve the turbidity, retention, and dehydration efficiency in accordance with the speeding up of paper machine and closing of white water.

Registered Patent Publication No. 10-0697547 (Announcement on March 21, 2007)

An object of the present invention is to provide a holding method and a holding system for manufacturing industrial paper for improving the turbidity of process white water.

It is also an object of the present invention to provide a holding method and a holding system for manufacturing industrial paper to improve the holding rate and dehydration efficiency.

The objects of the present invention are not limited to the objects mentioned above, and other objects and advantages of the present invention not mentioned can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. In addition, it will be readily appreciated that the objects and advantages of the present invention can be realized by means of the appended claims and combinations thereof.

Retention method for manufacturing industrial paper for improving turbidity of process white water according to the present invention comprises: (a) adding a first retention agent to white water that is dehydrated during the papermaking process and the stock is received to primary agglomerate anionic substances; (b) secondary agglomeration of the anionic material by adding a second retention agent to the primary agglomerated white water; And (c) adding an bentonite particle to the secondary agglomerated white water for tertiary aggregation and adsorption of the anionic material; wherein the first retention agent comprises a first cationic polyacrylamide, and The second retention agent includes a second cationic polyacrylamide, and the ionicity of the second cationic polyacrylamide is greater than that of the first cationic polyacrylamide.

The holding system for manufacturing industrial paper for improving the turbidity of process white water according to the present invention includes a storage container in which a stock is accommodated; A tank that stores white water that is dehydrated during the papermaking process and is disposed on the side of the storage container to receive feedstock transferred from the storage container; A fan pump which is disposed on the side of the tank and transports white water containing the stock discharged from the tank; A particle removal unit disposed on the side of the fan pump to remove particles larger than agglomerate size in the white water in which the feedstock transferred from the fan pump is accommodated; And an injection unit disposed on the side of the particle removal unit and injecting white water containing the feedstock transferred from the particle removal unit onto a wire, wherein the first retention agent and the second retention agent are provided at the inlet or outlet of the fan pump. The anionic material is firstly aggregated and secondly aggregated by sequentially adding a retention agent, and the bentonite particles are added to the inlet or outlet of the particle removal unit to thirdly aggregate and adsorb the anionic material, and the first retention agent Is a first cationic polyacrylamide, a second retention agent comprises a second cationic polyacrylamide, and the ionicity of the second cationic polyacrylamide is ionic of the first cationic polyacrylamide. It is characterized by being larger.

The holding method and holding system for manufacturing industrial paper according to the present invention are pre-agglomerated by adding a low-ionic cationic polyacrylamide as a holding agent, and then adding a cationic polyacrylamide having higher ionicity than the holding agent used for the pre-aggregation to the secondary It is agglomerated and reaggregated (re-adsorbed) with bentonite particles, which has an excellent effect in improving turbidity as well as retention rate and dehydration efficiency.

The holding method and the holding system for manufacturing industrial paper are customized systems according to changes in papermaking technology, and are tailored to the purification of process white water.

In addition to the above-described effects, the concrete effects of the present invention will be described together while describing the specific matters for carrying out the invention.

1 is a flowchart showing a method for holding industrial paper according to the present invention.
2 schematically shows the device of the holding system.

The above-described objects, features, and advantages will be described in detail below with reference to the accompanying drawings, and accordingly, a person skilled in the art to which the present invention pertains can easily implement the technical spirit of the present invention. In describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

In the following, the arrangement of any component in the "upper (or lower)" or "upper (or lower)" of the component means that the arbitrary component is disposed in contact with the upper surface (or lower surface) of the component. In addition, it may mean that other components may be interposed between the component and any component disposed on (or under) the component.

Also, when a component is described as being "connected", "coupled" or "connected" to another component, the components may be directly connected to or connected to each other, but other components may be "interposed" between each component. It should be understood that "or, each component may be" connected "," coupled "or" connected "through other components.

Hereinafter, a holding method and a holding system for manufacturing industrial paper for improving the turbidity of process white water according to some embodiments of the present invention will be described.

The present invention is an invention studied to improve the turbidity of process white water in a holding system that is focused on holding and dewatering by increasing the speed of a paper machine when manufacturing industrial paper.

Here, the hold is literally left to be mixed with pulp and auxiliary materials, which are the main raw materials of the paper, so as to be applied on the wire, and the degree of the amount of the remaining amount on the wire compared to the amount of the raw material applied to the paper can be grasped. You can.

1 is a flow chart showing a method for holding industrial paper according to the present invention.

Referring to FIG. 1, the method for holding industrial paper of the present invention is the step of primary aggregation by adding a first cationic polyacrylamide (S110), and a second cationic greater than the ionic property of the first cationic polyacrylamide. It includes the step of secondary agglomeration by adding polyacrylamide (S120) and the third aggregation and adsorption by adding bentonite particles (S130).

Primary aggregation by adding the first cationic polyacrylamide (S110)

Anionic substances are first aggregated by adding a first retention agent to white water that is dehydrated during the papermaking process.

The white water contains the stock, and the white water containing the stock may be stored in a wet pulp storage container such as a machine chest.

The concentration of the stock may be approximately 1 to 5%, and the white water may be in a slurry state with high turbidity. For example, the turbidity of the white water may be 2000 NTU or more.

In the white water in which the feedstock is accommodated, there are anionic fibers or microfibers, and by adding a first retention agent, these anionic micromaterials can be primarily aggregated using electrical conductivity. The first retaining agent is added to better retain, and is adsorbed to an anionic fiber or aggregated with microfibers in the stock to form a first floc.

It is preferable that the first retention agent of the present invention includes a first cationic polyacrylamide (C-PAM). The first cationic polyacrylamide is a polymer containing ethane aluminum, N, N, N-trimethyl-2-[(1-oxo-2-propenyl) oxy] chloride, 2-propeneamide, It can be prepared by emulsifying the aqueous phase and the oil phase.

The aqueous phase can be formed as follows.

The water-soluble phase contains 10 to 40 parts by weight of a cationic quaternary monomer, 0.1 to 2 parts by weight of a molecular weight modifier, 0.1 to 10 parts by weight of a buffer, and 3 to 5 parts by weight of a neutralization modifier based on 100 parts by weight of acrylamide. The acrylamide is added as a nonionic monomer. The cationic quaternary monomer may include one or more of dimethyl aminoethyl acrylate methyl chloride, dimethyl aminoethyl acrylate benzyl chloride, and dimethyl aminoethyl methylacrylate methyl chloride. The cationic quaternary monomer may be included in 10 to 70 parts by weight, preferably 10 to 40 parts by weight. When the addition amount of the cationic quaternary monomer is out of 10 to 40 parts by weight, it may be difficult to control the ionicity of the retention agent to a region of 0.5 to 2.0 meq / g. The molecular weight modifier may include one or more of sodium hypophosphite and hydroxy acetic acid. When the addition amount of the molecular weight modifier is 0.1 to 2 parts by weight, it may be difficult to control the desired molecular weight. The buffer may include at least one of succinic acid, ammonium chloride and maleic acid. When the addition amount of the buffer is out of 0.1 to 10 parts by weight, there is a problem in reaction stability during polymerization. In addition, the neutralization control agent may include one or more of sodium hydroxide, ammonia water, and potassium carbonate. The neutralization control agent is preferably added in 3 to 5 parts by weight based on pH 3 to 5, a slight difference in the amount added may occur.

The oil phase can be formed as follows.

Hydrocarbon oil contains 10 to 30 parts by weight, emulsifier 5 to 11 parts by weight. In the oil phase, acrylamide is not included, and the content of the components included in the oil phase is based on 100 parts by weight of acrylamide.

The hydrocarbon oil is C12 ~ 14, and specific gravity is 0.75 ~ 1.0. The hydrocarbon oil consists of water and oil. The addition amount of the oil is usually in the reverse phase emulsion polymerization W / O ratio is 2.2 to 3.0, after confirming sufficient verification of the emulsion viscosity and emulsion polymerization stability, the addition amount can be determined in the range of 10 to 30 parts by weight.

The emulsifier includes a hydrophobic emulsifier and a hydrophilic emulsifier. The hydrophobic emulsifier includes sorbitan monooleate HLB1-7. The hydrophilic emulsifier includes at least one of polyoxyethylene monooleate and polyoxyethylene laurylate. Components included in the hydrophilic emulsifier may have an HLB of 8 to 12. When the amount of the emulsifier added exceeds 5 to 11 parts by weight, sufficient emulsification of the aqueous phase and the oil phase may not be achieved.

The first cationic polyacrylamide can be prepared by mixing and emulsifying the aqueous phase and the oil phase at 0.002 to 0.1 parts by weight of the initiator and 1 to 10 parts by weight of the dispersant at 35 to 60 ° C. In the process of emulsifying, it is possible to make a stable emulsion polymerization product when the particle size of the first cationic polyamide produced is 500 to 1500 nm based on the emulsifier and the emulsification time.

The initiator includes at least one of ammonium persulfate (ammonium persulfate, (NH ₄ ) ₂ S ₂ O ₈ ), sodium sulfite (sodium sulfite, Na ₂ SO ₃ ) and azobis hydrochloric acid. The dispersant includes polyoxyethylene laurylates having an HLB of 8 to 14.

The first cationic polyacrylamide prepared in this way may be added to white water in the form of an emulsion or powder, and exhibits low ionicity of 0.5 to 2.0 meq / g. The first cationic polyacrylamide represents 30 to 42% of the polymer content in the emulsion, and 87 to 100% in the powder. In addition, the number of moles of cation quaternary monomer represents 4 to 20% in the emulsion and powder, and the molecular weight represents 3 to 10 (million).

In the present invention, based on the weight of white water, when the first retention agent is added 300 ~ 1200ppm exhibits an excellent turbidity improving effect.

Step of secondary agglomeration by adding a second cationic polyacrylamide larger than the ionic property of the first cationic polyacrylamide (S120)

Subsequently, a second retention agent is added to the primary agglomerated white water to secondary agglomerate the anionic material.

The primary agglomerated white water contains a stock, and the stock may be continuously transported by a fan pump. The primary agglomerated white water may have a lower turbidity than the unagglomerated white water or a slurry having the same turbidity.

In the primary agglomerated white water, non-agglomerated microfibers may be present, and by adding a second retention agent, an anionic material may be secondaryly agglomerated. The second retention agent aggregates with the microfibers in the stock to form a second floc.

The first floc formed during the primary agglomeration is mechanically decomposed by a mechanical shear treatment, and the decomposed floc forms a more compact second floc while introducing a second retention agent. The flocs formed in this way generate a lot of adsorption between fibers, improve turbidity of white water, and at the same time, form favorable conditions for retention and retention.

In this paper-making process, fiber retention is an important factor, and in the order in which the retention agent can react, the primary reaction is anionic micromaterial, secondary reaction is microfiber, and tertiary reaction is long fiber.

If, in the papermaking process, the second holding agent is first introduced, the reactor is blocked at the zeta potential of the fiber as the reaction occurs with a larger diameter or longer fiber than the microfiber. In this state, when the first retention agent is added to the rear end, the ionicity of the first retention agent is low, and the reactor cannot be found, and the aggregation performance and retention performance tend to decrease.

Therefore, as in the present invention, it is preferable to first input the first retention agent and then the second retention agent.

It is preferable that the second retention agent of the present invention includes a second cationic polyacrylamide (C-PAM). It is preferable that the ionicity of the second cationic polyacrylamide is greater than that of the first cationic polyacrylamide.

The second cationic polyacrylamide is a polymer containing ethane aluminum, N, N, N-trimethyl-2-[(1-oxo-2-propenyl) oxy] chloride, 2-propeneamide, It can be prepared by emulsifying the aqueous phase and the oil phase. The second cationic polyacrylamide can be adjusted to a high ionicity of 2.0 to 3.5 meq / g by adding a larger amount of cationic quaternary monomer than the first cationic polyacrylamide.

The aqueous phase can be formed as follows.

The water-soluble phase contains 50 to 70 parts by weight of a cationic quaternary monomer, 0.1 to 2 parts by weight of a molecular weight modifier, 0.1 to 10 parts by weight of a buffer, and 3 to 5 parts by weight of a neutralization modifier based on 100 parts by weight of acrylamide. The cationic quaternary monomer may be included in 10 to 70 parts by weight, preferably 50 to 70 parts by weight. When the addition amount of the cationic quaternary monomer exceeds 50 to 70 parts by weight, it may be difficult to control the ionicity of the retention agent to the region of 2.0 to 3.5 meq / g. Matters for each component are as described above on the first aqueous cationic polyacrylamide.

The oil phase can be formed as follows.

Hydrocarbon oil contains 10 to 30 parts by weight, emulsifier 5 to 11 parts by weight. In the oil phase, acrylamide is not included, and the content of the components included in the oil phase is based on 100 parts by weight of acrylamide.

The hydrocarbon oil is C12 ~ 14, and specific gravity is 0.75 ~ 1.0. The hydrocarbon oil consists of water and oil. The addition amount of the oil is usually in the reverse phase emulsion polymerization W / O ratio is 2.2 to 3.0, after confirming sufficient verification of the emulsion viscosity and emulsion polymerization stability, the addition amount can be determined in the range of 10 to 30 parts by weight.

The emulsifier includes a hydrophobic emulsifier and a hydrophilic emulsifier. The emulsifier is as described above in the oil phase of the first cationic polyacrylamide.

A second cationic polyacrylamide can be prepared by mixing and emulsifying the aqueous phase and the oil phase at 0.002 to 0.1 parts by weight of the initiator and 1 to 10 parts by weight of the dispersing agent at 35 to 60 ° C. In the process of emulsifying, it is possible to make a stable emulsion polymerization product when the particle diameter of the resulting second cationic polyamide is 500 to 1500 nm based on the emulsifier and the emulsification time.

Details of the initiator and dispersant are as described above in the first cationic polyacrylamide.

The second cationic polyacrylamide prepared as described above exhibits ionicity of 2.0 to 3.5 meq / g, and may be added to the white water in the form of an emulsion or powder. The second cationic polyacrylamide shows a polymer content of 36 to 50% in the emulsion, and a polymer content of 87 to 100% in the powder. In addition, the number of moles of the cationic quaternary monomer represents 27 to 46% in the emulsion and powder, and the molecular weight represents 5 to 9 (million).

In the present invention, based on the weight of the white water, when the second retention agent is added 500 ~ 1300ppm exhibits excellent retention and dehydration improvement effect.

Between the step S120 and the step S130, which will be described later, the method may further include removing particles (foreign matter) larger than the aggregate size present in the white water in which the stock is accommodated.

As particles (foreign matter) having a larger size than the first floc and / or the second floc, which are agglomerates, are removed through the screen, the turbidity of the white water can be further improved and the quality of the stock may be improved.

The particle removal step of removing the foreign matter may be performed in the particle removal unit 50 in which a mesh-sized strainer is disposed, but is not limited thereto.

The third step of coagulation and adsorption by adding bentonite particles (S130)

Subsequently, by adding bentonite particles, which are viscous swelling substances, to the secondary aggregated white water, the anionic substance is subjected to tertiary aggregation and adsorption.

In this step, the floc decomposed by the mechanical shearing treatment can be more densely reaggregated and adsorbed by adding the inorganic anion bentonite particles. In this step, the re-agglomeration is achieved by reacting mainly with long fibers having a larger diameter or a longer length than the fine fibers.

Accordingly, it improves the turbidity of white water and exhibits excellent retention efficiency.

In the present invention, when the bentonite particles are added in an amount of 1000 to 2500 ppm based on the weight of white water, they exhibit excellent reaggregation and adsorption efficiency.

Steps S110 to S130 may be performed by a fan pump, while the white water in which the stock is received is continuously transferred.

In the last step after the step S130, the step of injecting the stock on the wire may be further included. The injected stock is dehydrated, formed into a sheet, and then dried.

On the other hand, if there is no input position in the papermaking process, the first retention agent and the second retention agent may be added simultaneously before the bentonite is introduced.

2 schematically shows the device of the holding system.

Referring to Figure 2 will be described with respect to the pending process for manufacturing industrial paper of the present invention.

The holding system may be performed in a space in which the storage container 10, the tank 20, the fan pumps 30 and 40, the particle removal unit 50 and the injection unit 60 are sequentially arranged.

The location where the first retention agent, the second retention agent, and the bentonite particles are introduced may be selected in a manner using a physical shear force using a paper transfer means. This means that the input location is selected using manufacturing facilities.

Wet pulp (stock) is stored in the storage container (10). The wet pulp is continuously transported by fan pumps 30 and 40, which are devices that transport white water and stock.

A tank 20 in which white water is stored is disposed on a side of the storage container 10. The tank 20 is supplied with a feedstock transferred from the storage container 10. The feedstock is transferred to the particle removal unit 50 and the injection unit 60 via the tank 20.

Fan pumps 30 and 40 are disposed on the side of the tank 20. The fan pumps 30 and 40 may be at least one, and in FIG. 2, the first fan pump 30 and the second fan pump 40 are illustrated. In the present invention, each of the first retention agent and the second retention agent may be introduced to the inlet or outlet of the fan pump. For example, the first retention agent is first introduced to the inlet or outlet of the first fan pump 30 to preaggregate, and the second retention agent is introduced to the inlet or outlet of the second fan pump 40 to secondary agglomeration. I can do it.

Alternatively, if there is no input position in the paper-making process, the first retention agent and the second retention agent may be simultaneously added to agglomerate prior to bentonite injection.

The flocs aggregated by the first retention agent and the second retention agent may be reaggregated while being decomposed by shear treatment.

Particle removal parts 50 are disposed on the side of the fan pumps 30 and 40. The particle removal unit 50 removes particles larger than the agglomerate size among the white water in which the feedstock transferred from the fan pumps 30 and 40 is accommodated.

After the second retention agent is added, bentonite particles may be introduced to the front end or the rear end of the particle removal unit 50. Bentonite particles are introduced to reagglomerate and resorb, thereby exhibiting excellent retention efficiency in the stock.

When the bentonite particles are input to the front end of the particle removal unit 50, re-agglomeration and re-adsorption are performed, and the feed material transferred by the fan pump removes the coarse particles in the raw material from the particle removal unit 50, that is, foreign matter. Then, it is transferred to the injection unit 60.

When the bentonite particles are introduced into the rear end of the particle removal unit 50, after removing the foreign matter from the particle removal unit 50, re-agglomeration and re-adsorption are made, and transferred to the injection unit 60.

An injection portion 60 is disposed on the side of the particle removal portion 50. The injection unit 60 injects the raw materials supplied by the fan pumps 30 and 40 onto the wire at a uniform speed over the width direction of the paper machine.

In this way, the pulp and subsidiary materials are aggregated, broken, and re-agglomerated in order to hold, affecting the turbidity of white water, dehydration and agglomeration in the process, thereby affecting productivity and quality.

In the present invention, by selecting a first retention agent, a second retention agent having higher ionicity than the first retention agent, and bentonite, synergistic effect in terms of retention and dehydration efficiency as well as improvement in turbidity can be achieved, thereby enabling more efficient retention. .

Looking at the specific embodiment of the holding method for manufacturing industrial paper for improving the turbidity of the process white water as follows.

1) Raw materials and white water were prepared by taking samples of Ajin Paper and preparing them so that the feedstock concentration was 1%. The physical properties of the prepared 1% stock and white water are as follows.

[Table 1]

2) As shown in Table 2, the ionic change of the cationic polyacrylamide (C-PAM) as the second retention agent was fixed, and the molecular weight was fixed to 7 million, and the performance of ionic properties was verified as shown in Table 3.

Cationic polyacrylamides (C-PAM) of Samples 1-4 in Table 2 were prepared as follows.

First, with respect to 100 parts by weight of acrylamide, a cationic quaternary monomer (dimethyl aminoethyl acrylate methyl chloride, dimethyl aminoethyl acrylate benzyl chloride, dimethyl aminoethyl methylacrylate methyl chloride) is adjusted to 10 to 70 parts by weight, and molecular weight An aqueous phase was prepared by mixing 1 part by weight of a regulator (sodium hypophosphite), 10 parts by weight of a buffer (ammonium chloride), and 3 parts by weight of a neutralizing regulator (ammonia water, potassium carbonate).

Next, 10 parts by weight of a hydrocarbon oil having a W / O ratio of 2.5 and 10 parts by weight of an emulsifier were mixed to prepare an oil phase.

Subsequently, the prepared aqueous phase and the oil phase were stirred at 40 ° C. in the presence of 0.1 parts by weight of an initiator ((NH ₄ ) ₂ S ₂ O ₈ ) and 1 part by weight of a dispersant (polyoxyethylene laurylate) to prepare a cationic polyacrylamide. It was prepared.

[Table 2]

[Table 3]

Referring to Table 3, the retention and dehydration portion showed a good tendency at the 3 meq / g (sample 3) portion. The turbidity portion showed a good tendency at 1 eq / g (sample 1).

2) As shown in Table 4, retention agents (C-PAM (1), C-PAM (2)) and bentonite particles were prepared.

The first cationic polyacrylamide (C-PAM (1)) used in Table 4 was prepared as follows. It was prepared in the same manner as in the production method of C-PAM except that 10 parts by weight of a cationic quaternary monomer and 2 parts by weight of a molecular weight modifier were added.

[Table 4]

The addition amount of C-PAM (1) was changed, and the addition amount of C-PAM (2) and bentonite was fixed, and performance was observed as in Table 5.

[Table 5]

Referring to Table 5, C-PAM (2) alone shows insufficient performance in retention and dehydration, and shows little improvement in turbidity.

On the other hand, experiments by fusion of C-PAM (1) and C-PAM (2) show excellent results in retention and dehydration, and the effect of improving turbidity appears to be great. As the bentonite particles were added together with C-PAM (1) and C-PAM (2), they showed significantly reduced turbidity, indicating good retention.

Therefore, these results indicate that the use of C-PAM (1), C-PAM (2) and bentonite as retention agents improves both turbidity and retention and dehydration performance of white water.

However, when the added amount of C-PAM (1) exceeds 1200ppm, as the amount of the retaining agent is increased in the paper, it becomes possible to cause the paper property and process to be disrupted due to over-retention. Accordingly, the retention rate is required to be managed at approximately 90% or less, and it is desirable to adjust the experimental results according to process requirements when applying for reference.

As described above, the present invention is a technology tailored to the purification of process white water with a customized retention system according to changes in papermaking technology.

In the related art, since an inorganic coagulant, a cationic polymer, and an anionic polymer were added to perform a fiber reaction with a polymer at the rear end, there was a limitation in improving the problem of turbidity and improving turbidity. In addition, there was a problem in that the anionicity in white water was increased, and thus a bad effect on the process was caused by a low retention rate. In the case of paper application, it is usually a holding system suitable for white paper, and is not suitable for industrial paper.

In the present invention, by selecting a first retention agent, a second retention agent having higher ionicity than the first retention agent, and bentonite, and improving the conventional problems, synergistic effect in terms of retention and dehydration efficiency as well as turbidity improvement, more Efficient withholding can proceed.

As described above, the present invention has been described with reference to the exemplified drawings, but the present invention is not limited by the examples and drawings disclosed in the present specification. It is obvious that modifications can be made. In addition, although the operation and effect according to the configuration of the present invention has not been explicitly described while describing the embodiment of the present invention, it is natural that the predictable effect by the configuration should also be recognized.

10: Storage container
20: tank
30: first fan pump
40: second fan pump
50: particle removal unit
60: injection unit

Claims (11)

(a) primary agglomeration of the anionic material by adding a first retention agent to white water, which is dehydrated during the papermaking process and the stock is received;
(b) secondary agglomeration of the anionic material by adding a second retention agent to the primary agglomerated white water; And
(c) the third aggregation and adsorption of anionic substances by adding bentonite particles to the second aggregated white water;
The first retention agent comprises a first cationic polyacrylamide, the second retention agent comprises a second cationic polyacrylamide,
The second cationic polyacrylamide has an ionic property greater than that of the first cationic polyacrylamide.
delete According to claim 1,
The first cationic polyacrylamide
Aqueous phase containing 10 to 40 parts by weight of a cationic quaternary monomer, 0.1 to 2 parts by weight of a molecular weight modifier, 0.1 to 10 parts by weight of a buffer, 3 to 5 parts by weight of a neutralizing regulator, and hydrocarbon oil with respect to 100 parts by weight of acrylamide Method for holding industrial paper produced by emulsifying by mixing an oil phase containing 10 to 30 parts by weight and 5 to 11 parts by weight of an emulsifier with an initiator and a dispersant.
delete According to claim 1,
The second cationic polyacrylamide
Aqueous phase containing 50 to 70 parts by weight of a cationic quaternary monomer, 0.1 to 2 parts by weight of a molecular weight modifier, 0.1 to 10 parts by weight of a buffer, 3 to 5 parts by weight of a neutralizing regulator, and hydrocarbon oil with respect to 100 parts by weight of acrylamide Method for holding industrial paper produced by emulsifying by mixing an oil phase containing 10 to 30 parts by weight and 5 to 11 parts by weight of an emulsifier with an initiator and a dispersant.
According to claim 1,
The ionicity of the first cationic polyacrylamide is adjusted to 0.5 to 2.0 meq / g,
The second cationic polyacrylamide has an ionic property of 2.0 to 3.5 meq / g, which is a method for holding industrial paper.
According to claim 1,
Between steps (b) and (c) above,
A method of holding industrial paper further comprising the step of removing particles larger than the size of aggregates present in the white water in which the stock is accommodated.
delete According to claim 1,
The holding method for manufacturing industrial paper is a holding method for producing industrial paper performed by a fan pump, while white water containing the stock is transferred.
According to claim 1,
After the third step of coagulation and adsorption,
Injecting the stock on the wire; The holding method for manufacturing industrial paper further comprising.
A storage container accommodating stocks;
A tank that stores white water that is dehydrated during the papermaking process and is disposed on the side of the storage container to receive feedstock transferred from the storage container;
A fan pump which is disposed on the side of the tank and transports white water containing the stock discharged from the tank;
A particle removal unit disposed on the side of the fan pump to remove particles larger than agglomerate size in the white water in which the feedstock transferred from the fan pump is accommodated; And
It is disposed on the side of the particle removal unit, the injection unit for injecting the white water containing the feed material transferred from the particle removal unit on the wire; includes,
First and second agglomeration agents are sequentially added to the inlet or outlet of the fan pump to first and second agglomerate anionic substances.
Bentonite particles are added to the inlet or outlet of the particle removal unit to perform the third aggregation and adsorption of anionic substances,
The first retention agent comprises a first cationic polyacrylamide, the second retention agent comprises a second cationic polyacrylamide,
The ionicity of the second cationic polyacrylamide is greater than that of the first cationic polyacrylamide.

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