KR101850654B1 - Method of fillers preflocculation under papermaking - Google Patents

Abstract

The present invention relates to a method of pre-flocculating a filler for papermaking. More specifically, the method includes: a step of transforming at least two kinds of solid-mixed fillers into slurry; and a step of sequentially adding first and second flocculators while stirring the slurry, and then, forming a filler flocculation body by stopping stirring the slurry. If a filler for papermaking is pre-flocculated through a dual polymer system according to the present invention, a flocculation body having an optimal size is able to be made, and then, the body applied to paper production is capable of improving physical properties such as tensile strength, internal bonding strength, and folding strength while at the same time improving the retention of the filler, thereby stabilizing the process.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a filler preflocculation under papermaking process,

The present invention relates to a method for pre-agglomerating a papermaking filler capable of improving the strength and physical properties of papermaking as well as improving the papermaking process by pre-aggregating the papermaking filler immediately before the papermaking filler is introduced into the process.

The manufacturing process of the printing paper is performed by forming, draining, pressing, and pressing on a pulp slurry (pulp slurry) mixed with filler slurry on a paper machine (paper machine) Dried and then finished with paper (see Fig. 1).

The main material of the printing paper is pulp, and it is used with the filler which is inorganic material to reduce the cost as well as to improve the printability by giving various characteristics to the paper. Most pulp of domestic consumption is imported from abroad, and pulp supply and demand in the global market has always been unstable due to the environmental protection and resource weaponization policies of each country.

Accordingly, various paper making methods that can reduce the amount of high-priced pulp but increase the filler content that is relatively low in price relative to the pulp price have been continuously tried by related industry researchers and paper-making technicians.

However, if the filler content is increased to reduce the production cost, the drying force of the paper can not be reduced. Therefore, the research and the technology development have been progressed so as to mutually satisfy the two conflicting concepts at an appropriate level.

The pulp and the filler come into contact with each other in a slurry state in the production process. The size of each unit particle of the filler in the slurry state is relatively small compared to the size (length) of each unit fiber of the refining pulp, and thus has a relatively large specific surface area. Pulp and filler have the same surface charge of anionic. Because of these ionic properties and the relatively large specific surface area of the filler, the filler physically / chemically acts as a factor that interferes with the natural contact and bonding of the pulp fibers and the fibers.

Most of all, it is desirable that the filler content should be increased for cost reduction. However, as the filler content increases, the dry strength (tensile strength, internal bond strength, bending strength, etc.) of the paper will decrease inversely as the filler content increases. The grassy driving ability will also deteriorate.

As a solution to this problem, if the filler is first pre-aggregated using the polymer additive and then applied to the production process, the possibility of contacting the fibers with each other by the reduced specific surface area of the filler will increase, and the increase of the bonding force This will result in an improvement in the dry strength of the paper.

In a similar concept, if the production conditions are not required to further improve the drying strength, the filler content of the paper can be increased by the amount of the strength of the increased value that can be improved by the coagulation, There will be.

Korean Patent No. 1742962 (2017.06.02.)

It is an object of the present invention to improve the dry strength of the finished paper primarily by pre-agglomerating the filler with the polymer additive just prior to the input of the production process, when using the filler slurry which is essentially used in the process of producing the printing paper, The present invention provides a method of agglomerating a padding filler capable of reducing the cost and improving the process because the retention performance of the filler is improved.

According to an aspect of the present invention, there is provided a method for pre-agglomerating a filler for papermaking, the method comprising: slurrying two or more kinds of solid mixed fillers; And sequentially charging the first flocculating agent and the second flocculating agent while stirring the filler slurry and stopping the stirring to form a filler preagglomerate.

The present invention can produce an aggregate having an optimum size when the paper filler is pre-agglomerated using a dual polymer system. When the paper is used for producing printing paper, tensile strength, internal bond strength, The physical properties are improved and the retention performance of the filler is improved, so that the process can be stabilized.

Brief Description of the Drawings Fig. 1 schematically shows a process for producing a printing paper; Fig.
FIG. 2 is a flow chart showing a pre-agglomeration method for a pile according to an embodiment of the present invention; FIG.
3 is a diagram showing a line aggregation distribution diagram;
Figure 4 shows the basic reaction mechanism of the line agglutination reaction;
Figure 5 shows morphological changes of the filler;
FIG. 6 is a schematic view showing the standard of installation of the production process in which the pre-agglomerating method for papermaking of the present invention is applied;
FIG. 7 is a diagram showing an input order and a stirring condition of a first flocculant M-500 and a second flocculant MS-400 as an example of laboratory experimental conditions;
8 shows a particle size analyzer (Mastersizer 3000E / Malvern);
Fig. 9 is a graph showing the results of the comparison of the results of Comparative Example 2 and Example 1 to Example 5 (a), Comparative Example 3, Example 6 to Example 10 (b), and Comparative Example 4 and Examples 11 to 15 (c) Lt; RTI ID = 0.0 > agglomerated < / RTI >
Figure 10 shows a hold / dehydrator (RDA);
Fig. 11 is a graph showing the results of comparison between the results of Comparative Example 2 and Examples 1 to 5 (a), Comparative Example 3, Examples 6 to 10 (b), and Comparative Examples 4 and 11 to 15 (c) A comparison of the filtrate turbidity of papermaking materials including pre-agglomerated pre-agglomerated filler pre-agglomerates by line agglomeration;
12 is a view showing a hand-held machine; And
Fig. 13 is a graph showing the results of comparison between the results of Comparative Example 2 and Examples 1 to 5 (a), Comparative Example 3, Examples 6 to 10 (b), and Comparative Examples 4 and 11 to 15 (c) FIG. 5 is a view showing the internal bond strength of a water-base paper prepared using pre-agglomerated plywood agglomerates as a pre-agglomeration method.

Hereinafter, the method for pre-agglomerating paper fillers according to the present invention will be described in more detail.

The inventors of the present invention found that when a first flocculant and a second flocculant were added to a filler at a certain ratio during the study of the method for flocculation of paper filler, an effective filler preaggregate was produced. It was found that the drying strength of the paper was improved as a result of increasing the bonding force between the pulp and the pulp compared to the conventional conditions of using the filler.

The present invention relates to a method for pre-agglomerating a filler for papermaking, comprising the steps of: slurrying two or more kinds of solid mixed fillers; And sequentially charging the first flocculating agent and the second flocculating agent while stirring the filler slurry and stopping the stirring to form a filler preagglomerate.

Specifically, Fillers preflocculation is a method in which polymer additives are injected into filler slurry immediately before the filler is injected into the process, and when the individual filler particles are coagulated, the average diameter of the unit particles is 2 μm Each particle of the filler undergoes an agglomeration process, resulting in a morphological change in shape, and the average diameter of the final agglomerates is increased to the level of 20 ~ 40 ㎛. Of course, the size of the agglomerates depends on the amount of polymer used, and the average diameter range of the agglomerates suggested above is considered to be the optimum size to obtain the most effective filler aggregation.

The appearance of the filler agglomerates changed by line agglomeration will naturally decrease the total specific surface area based on the same weight, and the line agglomerated filler will be easier to retain when it meets the pulp fibers. As a result, the bondable area between the pulp fibers will increase relatively more than the conventional conditions, and the bond strength between the fibers will be increased, which means that the dry strength of the paper is improved.

The filler may be at least two selected from the group consisting of heavy calcium carbonate (GCC), light calcium carbonate (PCC), clay, talc, and titanium dioxide.

Specifically, as of today, global printing paper makers are most likely to use heavy calcium carbonate (GCC) and light calcium carbonate (PCC) in the production of printing paper. The mixing ratio of calcium carbonate to calcium carbonate differs from producer to producer, and there are also factories which apply only one type of calcium carbonate to GCC, PCC, depending on the type of production site and purpose. The mixed filler used in the present invention is composed of 50% by weight of heavy calcium carbonate (GCC) and 50% by weight of hard calcium carbonate (PCC). The mixing ratio is only an example and is not an absolute standard.

The first coagulant may be amphoteric polyacrylamide, but is not limited thereto.

The first coagulant may be represented by the following general formula (1), but is not limited thereto.

[Chemical Formula 1]

In Formula 1,

n is a rational number of 0.3 or more and 0.8 or less,

m is the glass number of not less than 0.05 and not more than 0.5.

The second coagulant may be anionic polyacrylamide, but is not limited thereto.

The second coagulant may be represented by the following general formula (2), but is not limited thereto.

(2)

In Formula 2,

n 'is a rational number of 0.3 or more and 0.8 or less,

m 'is an glass number of not less than 0.01 and not more than 0.5.

Specifically, as one embodiment of the present invention, the first coagulant and the second coagulant used in the pre-flocculation method for papermaking according to the present invention are different from the first coagulant and the second coagulant which have been used in the prior art pre-flocculation method. Therefore, the differences are compared in Table 1 below.

Conventional technology Item Invention First coagulant Amphoteric Polymer
(High Charge,
Low Molecular Weight) Component
And
By each formulation
Chemical
Property The first coagulant Amphoteric PAM
(Medium Charge
Med. Mol. Weight)
Second coagulant Net Charge
Contrast / reverse charge
Low Charge
High Molecular Weight Second coagulant Anionic PAM
Medium Charge
Med. Mol. Weight First coagulant Branched Chain
(Branched chain)
Linear Chain
(Linear chain) Polymer Structure The first coagulant Branched Chain
(Branched chain) Solution
(Water Base)
Emulsion
(Oil Base) Polymer Form Solution
(Water Base) Second coagulant Linear Chain
(Linear chain) Polymer Structure Second coagulant Branched Chain
(Branched chain) Emulsion
(Oil Base) Polymer Form Solution
(Water Base)

The step of forming the filler pre-aggregate may include the step of charging the first flocculant while stirring the filler slurry at 800 to 1000 rpm for 5 to 10 seconds, and the second flocculant after 1 to 5 seconds, It is not.

In the step of forming the filler pre-aggregate, 0.20 to 0.72 parts by weight of the first flocculating agent and 0.04 to 0.40 parts by weight of the second flocculating agent are sequentially added to 100 parts by weight of the two or more kinds of solid mixed filler while stirring the filler slurry, And stopping to form a filler pre-aggregate, but is not limited thereto.

The step of forming the filler pre-aggregate may include the steps of sequentially charging 0.20 to 0.36 parts by weight of the first flocculating agent and 0.04 to 0.20 parts by weight of the second flocculating agent to 100 parts by weight of the two or more kinds of solid mixed filler during stirring of the filler slurry, And stopping to form a filler pre-aggregate, but is not limited thereto.

In the step of forming the filler pre-aggregate, 0.30 to 0.54 parts by weight of the first flocculating agent and 0.06 to 0.30 parts by weight of the second flocculating agent are sequentially added to 100 parts by weight of the two or more kinds of solid mixed fillers while stirring the slurry, And stopping to form a filler pre-aggregate, but is not limited thereto.

In the step of forming the filler pre-aggregate, 0.40 to 0.72 parts by weight of a first flocculant and 0.08 to 0.40 parts by weight of a second flocculant are sequentially added to 100 parts by weight of at least two kinds of solid mixed fillers while stirring the filler slurry, And stopping to form a filler pre-aggregate, but is not limited thereto.

Hereinafter, the method for pre-agglomerating paper fillers according to the present invention will be described in more detail with reference to the following examples. However, the present invention is not limited by these examples.

≪ Example 1 >

(Hereinafter referred to as " PCC ") having an average particle size of about 1 to 50% by weight, ground calcium carbonate (hereinafter referred to as " GCC ", average particle size: about 2 m) and 50% by weight of hard calcium carbonate 4 탆) was diluted with water to prepare a filler slurry having a concentration of 20 (%) based on calcium carbonate solids.

Thereafter, distilled water was used at a concentration of 0.2% (500-fold dilution), respectively, with a first flocculant (hereinafter referred to as' M-500 ') represented by the following formula 1 and a second flocculant represented by the following formula (hereinafter referred to as' MS- Diluted to prepare.

[Chemical Formula 1]

In Formula 1,

n is a rational number of 0.3 or more and 0.8 or less,

m is the glass number of not less than 0.05 and not more than 0.5.

(2)

In Formula 2,

n 'is a rational number of 0.3 or more and 0.8 or less,

m 'is an glass number of not less than 0.01 and not more than 0.5.

After the filler slurry was stirred at 900 rpm for 8 seconds, 0.36 part by weight of M-500 was added to 100 parts by weight of solid GCC and PCC mixed filler, and after 2 seconds, 0.04 part by weight of MS-404 was added.

After 60 seconds from the start of stirring, stirring was stopped to prepare a papermaking filler pre-agglomerate.

≪ Example 2 >

A pre-agglomerated papermaking filler was prepared under the same conditions as in Example 1 except that 0.32 part by weight of M-500 and 0.08 part by weight of MS-404 were added to 100 parts by weight of the solid GCC and PCC mixed filler.

≪ Example 3 >

Solid filler A pre-agglomerated papermaking filler was prepared under the same conditions as in Example 1, except that 0.28 parts by weight of M-500 and 0.12 parts by weight of MS-404 were added to 100 parts by weight of the mixed filler.

≪ Example 4 >

A filler pre-agglomerate for papermaking was prepared under the same conditions as in Example 1 except that 0.24 parts by weight of M-500 and 0.16 parts by weight of MS-404 were added to 100 parts by weight of the solid GCC and PCC mixed filler.

≪ Example 5 >

The pre-agglomerates for papermaking fillers were prepared under the same conditions as in Example 1 except that 0.20 parts by weight of M-500 and 0.20 parts by weight of MS-404 were added to 100 parts by weight of the solid GCC and PCC mixed filler.

≪ Example 6 >

The pre-agglomerates for papermaking fillers were prepared under the same conditions as in Example 1 except that 0.54 parts by weight of M-500 and 0.06 parts by weight of MS-404 were added to 100 parts by weight of the solid GCC and PCC mixed filler.

≪ Example 7 >

Solid filler A pre-agglomerated papermaking filler was prepared under the same conditions as in Example 1 except that 0.48 part by weight of M-500 and 0.12 part by weight of MS-404 were added to 100 parts by weight of the mixed filler.

≪ Example 8 >

A pre-agglomerated papermaking filler was prepared under the same conditions as in Example 1 except that 0.42 part by weight of M-500 and 0.18 part by weight of MS-404 were added to 100 parts by weight of the solid GCC and PCC mixed filler.

≪ Example 9 >

The pre-agglomerates for papermaking fillers were prepared under the same conditions as in Example 1 except that 0.36 parts by weight of M-500 and 0.24 parts by weight of MS-404 were added to 100 parts by weight of the solid GCC and PCC mixed filler.

≪ Example 10 >

The pre-agglomerates for papermaking fillers were prepared under the same conditions as in Example 1 except that 0.30 parts by weight of M-500 and 0.30 parts by weight of MS-404 were added to 100 parts by weight of the solid GCC and PCC mixed filler.

≪ Example 11 >

The pre-agglomerates for papermaking fillers were prepared under the same conditions as in Example 1 except that 0.72 parts by weight of M-500 and 0.08 parts by weight of MS-404 were added to 100 parts by weight of the solid GCC and PCC mixed filler.

≪ Example 12 >

A pre-agglomerate for papermaking filler was prepared under the same conditions as in Example 1, except that 0.64 part by weight of M-500 and 0.16 part by weight of MS-404 were added to 100 parts by weight of the solid GCC and PCC mixed filler.

≪ Example 13 >

The pre-agglomerates for papermaking fillers were prepared under the same conditions as in Example 1 except that 0.56 parts by weight of M-500 and 0.24 parts by weight of MS-404 were added to 100 parts by weight of the solid GCC and PCC mixed filler.

≪ Example 14 >

The pre-agglomerates for papermaking fillers were prepared under the same conditions as in Example 1, except that 0.48 parts by weight of M-500 and 0.32 parts by weight of MS-404 were added to 100 parts by weight of the solid GCC and PCC mixed filler.

≪ Example 15 >

A pre-agglomerated papermaking filler was prepared under the same conditions as in Example 1 except that 0.40 part by weight of M-500 and 0.40 part by weight of MS-404 were added to 100 parts by weight of the solid GCC and PCC mixed filler.

≪ Comparative Example 1 &

(Hereinafter referred to as " PCC ") having an average particle size of about 1 to 50% by weight, ground calcium carbonate (hereinafter referred to as " GCC ", average particle size: about 2 m) and 50% by weight of hard calcium carbonate 4 urn) slurry was mixed and the filler slurry diluted to a concentration of 20% based on solid GCC and PCC mixed filler was used as a control by stirring for 70 seconds at 900 rpm.

≪ Comparative Example 2 &

A pre-agglomerated papermaking filler was prepared under the same conditions as in Example 1 except that 0.40 part by weight of M-500 was added to 100 parts by weight of the solid GCC and PCC mixed filler.

≪ Comparative Example 3 &

A pre-agglomerated papermaking filler was prepared under the same conditions as in Example 1, except that 0.60 part by weight of M-500 was added to 100 parts by weight of the solid GCC and PCC mixed filler.

≪ Comparative Example 4 &

A pre-agglomerated papermaking filler was prepared under the same conditions as in Example 1 except that 0.80 part by weight of M-500 was added to 100 parts by weight of the solid GCC and PCC mixed filler.

<Experimental Example 1> Analysis of mean diameter and particle size distribution (cumulative volume distribution) of the pre-agglomerates of the filler

In order to analyze the average diameter and total particle size distribution of the pre-agglomerates for papermaking produced according to Examples 1 to 15 and Comparative Examples 1 to 4 according to the present invention, a laser particle size analyzer (Mastersizer 3000E / Malvern Instrument) was used (see Fig. 8), and the results are shown in Tables 2 to 4 and Fig.

Total
(M-500 + MS-404) Item M-500 MS-404 Average diameter Particle size distribution (cumulative volume distribution) D [4,3]] Dv (10) Dv (50) Dv (90) unit % % ㎛ ㎛ ㎛ ㎛

0.4 parts by weight Example 1 90 10 17.1 9.48 24.08 58.14 Example 2 80 20 19.0 8.92 26.45 59.94 Example 3 70 30 18.4 8.44 26.02 59.02 Example 4 60 40 17.6 9.57 25.07 58.87 Example 5 50 50 17.1 9.95 24.33 57.16 Comparative Example 1 0 0 3.07 1.64 3.35 7.52 Comparative Example 2 100 0 15.7 10.92 23.14 55.81

Total
(M-500 + MS-404) Item M-500 MS-404 Average diameter Particle size distribution (cumulative volume distribution) D [4,3]] Dv (10) Dv (50) Dv (90) unit % % ㎛ ㎛ ㎛ ㎛

0.6 parts by weight Example 6 90 10 27.2 11.14 29.98 63.80 Example 7 80 20 33.3 9.22 35.08 65.26 Example 8 70 30 30.0 9.94 32.22 64.34 Example 9 60 40 28.4 10.89 30.09 63.25 Example 10 50 50 27.0 11.72 28.90 62.18 Comparative Example 1 0 0 3.07 1.64 3.35 7.52 Comparative Example 3 100 0 20.2 11.24 25.22 62.04

Total
(M-500 + MS-404) Item M-500 MS-404 Average diameter Particle size distribution (cumulative volume distribution) D [4,3]] Dv (10) Dv (50) Dv (90) unit % % ㎛ ㎛ ㎛ ㎛

0.8 parts by weight Example 11 90 10 49.4 12.22 52.07 65.92 Example 12 80 20 56.0 11.24 58.24 67.90 Example 13 70 30 51.4 11.69 52.92 68.22 Example 14 60 40 45.5 12.04 48.12 66.27 Example 15 50 50 40.7 12.61 42.04 65.83 Comparative Example 1 0 0 3.07 1.64 3.35 7.52 Comparative Example 4 100 0 34.2 11.89 36.21 64.17

Referring to Table 2, when 0.4 parts by weight of flocculants (M-500 and MS-400) were added to 100 parts by weight of solid GCC and PCC mixed filler, a pre-aggregate having a diameter of 17 to 19 μm was prepared. Particularly, in Comparative Example 2, in the case of the pre-agglomerates pre-agglomerated by adding 0.40 parts by weight of M-500 to 100 parts by weight of the GCC and PCC mixed filler, the average diameter of the pre-agglomerates was relatively increased It can be seen that the bar formed at a small size has a weak degree of aggregation.

Further, referring to Table 2 above, when 0.6 parts by weight of two flocculants (M-500 and MS-400) were added to 100 parts by weight of solid GCC and PCC mixed filler, a pre-aggregate having a diameter of 27 to 30 μm was prepared Respectively. Particularly, in the case of the pre-agglomerates pre-agglomerated with 0.60 part by weight of M-500 relative to 100 parts by weight of the solid GCC and PCC mixed filler according to Comparative Example 3, the average diameter of the pre-agglomerates was relatively And the degree of aggregation is weak.

Further, referring to Table 4, when 0.8 parts by weight of flocculants (M-500 and MS-400) were added to 100 parts by weight of solid GCC and PCC mixed filler, a pre-aggregate having a diameter of about 40 to 50 탆 was prepared.

Referring to Tables 2 to 4, it can be seen that the average diameter increases as the content of the coagulant (M-500 and MS-404) increases.

However, when the mean diameter of the pre-agglomerates for papermaking is less than 20 탆, the filler can easily escape in the course of water in the paper raw material, and when the average diameter of the pre-agglomerates exceeds 40 탆, The large specific surface area of the agglomerate may be excessively increased to cause side effects of improvement of the intellect and the quality defect of the finished paper such as pin hole.

Therefore, it can be seen that the pre-agglomeration method (Examples 6 to 10) capable of producing the pre-aggregates having an average diameter in the range of 20 to 40 mu m is an excellent condition, and when using the first flocculant M-500 alone (Example 6 to Example 10) when the second flocculant MS-400 was used together with the dual polymer system (Comparative Example 3) (Table 3).

&Lt; Experimental Example 2 >

Cationic PAM (molecular weight: 4 million to 6 million), bentonite fine particles (density: 550 to 600 kg / m ³ ), and micro polymer (molecular weight: about 6 million, density: 1,050 kg / m ³ ) was used.

Specifically, a pulp slurry was prepared by mixing 5 wt% of softwood bleached kraft pulp (NBKP), 75 wt% of bleached kraft pulp (LBKP), and 20 wt% of a thermomechanical pulp (CTMP).

The pre-agglomerates for papermaking (using 30 parts by weight of the filler per 100 parts by weight of the pulp) prepared by the pre-agglomerating method for papermaking fillers according to Examples 1 to 15 and Comparative Examples 1 to 4 were put into pulp slurry, respectively , And each test material was prepared.

The dewatering performance was evaluated by a change in vacuum degree and the retention performance was evaluated by comparing the turbidity of the dewatered liquid passing through the wire using a Retention Drainage Analyzer (RDA) The results are shown in Tables 5 to 7 and FIG.

Total
(M-500 + MS-404) Item Application rate Actual input Hold Turbidity M-500 MS-404 M-500 MS-404 Turbidity Vacuum degree unit % % % % NTU mmHg

0.4 parts by weight Example 1 90 10 0.36 0.04 327 108 Example 2 80 20 0.32 0.08 298 107 Example 3 70 30 0.28 0.12 307 107 Example 4 60 40 0.24 0.16 314 108 Example 5 50 50 0.20 0.20 338 109 Comparative Example 1 0 0 0 0 377 112 Comparative Example 2 100 0 0.40 0 341 109

Total
(M-500 + MS-404) Item Application rate Actual input Hold Turbidity M-500 MS-404 M-500 MS-404 Turbidity Vacuum degree unit % % % % NTU mmHg

0.6 parts by weight Example 6 90 10 0.54 0.06 296 107 Example 7 80 20 0.48 0.12 282 106 Example 8 70 30 0.42 0.18 292 106 Example 9 60 40 0.36 0.24 306 107 Example 10 50 50 0.30 0.30 314 107 Comparative Example 1 0 0 0 0 377 112 Comparative Example 3 100 0 0.60 0 315 108

Total
(M-500 + MS-404) Item Application rate Actual input Hold Turbidity M-500 MS-404 M-500 MS-404 Turbidity Vacuum degree unit % % % % NTU mmHg

0.8 parts by weight Example 11 90 10 0.72 0.08 271 108 Example 12 80 20 0.64 0.16 264 108 Example 13 70 30 0.56 0.24 275 108 Example 14 60 40 0.48 0.32 287 108 Example 15 50 50 0.40 0.40 298 108 Comparative Example 1 0 0 0 0 377 112 Comparative Example 4 100 0 0.80 0 288 108

Specifically, as the content of the coagulant (M-500 and MS-400) increased, turbidity decreased when the pre-agglomerates prepared according to the pre-agglomeration method for papermaking according to Examples 1 to 15 were used, (See Tables 5 to 7).

However, as the content of the coagulant (M-500 and MS-400) increases, the pre-agglomerates for papermaking fillers will become larger than the average diameter of 40 to 50 μm.

Therefore, it can be seen that the effective amount of the coagulant is 0.6 part by weight (the sum of the two kinds of coagulant) of the coagulant (M-500 and MS-400) relative to 100 parts by weight of the solid content of the GCC and PCC mixed filler. Line aggregation conditions can be optimally seen (see Table 6 and Fig. 11).

&Lt; Experimental Example 3 > Evaluation of ash content and mechanical properties

Specifically, a pulp slurry was prepared by mixing 5 wt% of softwood bleached kraft pulp (NBKP), 75 wt% of bleached kraft pulp (LBKP), and 20 wt% of a thermomechanical pulp (CTMP).

According to the pre-agglomeration method for papermaking according to Examples 1 to 15 and Comparative Examples 1 to 4, pre-agglomerated papermaking filler pre-agglomerates were mixed with pulp slurry, The necessary paper stock was prepared.

After each preparation of the test materials, the test material is subjected to a paper property test such as forming, draining, pressing, and drying using a handsheet machine. A necessary water base paper was prepared.

The Handsheet machine shown in FIG. 12 is a one-step process that can be performed in one tester, such as molding, dehydration, compression, and drying (94/6 minutes).

For the evaluation of physical properties, the cemented weeds were subjected to a curing treatment for 6 hours under constant temperature and humidity conditions of temperature 23 and humidity 55%, and then the dry strength (internal bond strength, bending strength, tensile strength) and physical properties (Thickness, ash content) were measured, and the results are shown in Tables 8 to 10 and FIG.

Total
(M-500 + MS-404) Item Application rate Internal bond strength End
burglar Seal
burglar thickness Ash M-500 MS-404 unit % % J / m pcs kgf ㎛ %

0.4 parts by weight Example 1 90 10 149 19 1.97 101.0 22.6 Example 2 80 20 150 20 2.03 101.1 22.5 Example 3 70 30 150 20 2.04 101.1 22.5 Example 4 60 40 149 19 2.02 101.1 22.3 Example 5 50 50 149 19 2.00 101.1 22.3 Comparative Example 1 0 0 146 18 1.88 100.9 21.6 Comparative Example 2 100 0 148 19 1.97 101.1 22.2

Total
(M-500 + MS-404) Item Application rate Internal bond strength End
burglar Seal
burglar thickness Ash M-500 MS-404 unit % % J / m pcs kgf ㎛ %

0.6 parts by weight Example 6 90 10 153 20 2.04 101.2 22.9 Example 7 80 20 155 21 2.07 101.3 23.8 Example 8 70 30 154 21 2.07 101.2 23.8 Example 9 60 40 153 20 2.02 101.2 23.4 Example 10 50 50 153 20 2.02 101.1 22.8 Comparative Example 1 0 0 146 18 1.88 100.9 21.6 Comparative Example 3 100 0 152 19 1.99 101.0 22.7

Total
(M-500 + MS-404) Item Application rate Internal bond strength End
burglar Seal
burglar thickness Ash M-500 MS-404 unit % % J / m pcs kgf ㎛ %

0.8 parts by weight Example 11 90 10 151 21 2.05 101.2 23.3 Example 12 80 20 152 21 2.05 101.2 23.9 Example 13 70 30 151 21 2.04 101.2 23.8 Example 14 60 40 152 20 2.04 101.2 23.4 Example 15 50 50 150 20 2.04 101.2 23.5 Comparative Example 1 0 0 146 18 1.88 100.9 21.6 Comparative Example 4 100 0 151 19 2.03 101.1 23.0

The high ash content of the soils indicates the better pre-aggregation effect. Referring to Tables 8 to 10, when the total amount of the two coagulants (M-500 and MS-400) was increased, that is, when the pre-aggregates prepared according to the pre-agglomeration method for papermaking according to Examples 11 to 15 were used It can be seen that the ash content of the soils increased.

However, as the total amount of the two flocculants (M-500 and MS-400) is increased, the papermaking filler pre-agglomerates may become problematic in producing high quality paper because the average diameter is larger than 40 to 50 μm.

Therefore, it can be seen that the optimum amount of the flocculant is most effective to add 0.6 parts by weight of the total of two flocculants (M-500 and MS-400) to 100 parts by weight of the solid GCC and PCC mixed filler. (Table 9 and Fig. 13). &Lt; tb &gt; &lt; TABLE &gt;

In addition, mechanical properties such as internal bond strength, tensile strength and tensile strength are improved. When the filler pre-agglomerates pre-agglomerated by the methods of Examples 6 to 10 are used, the physical properties of the water base paper are improved It can be seen that the pre-aggregation conditions according to Example 7 are the best.

In addition, when the second flocculant MS-400 was applied together with a dual polymer system (Example 6 to Example 10) in comparison with the case where the first flocculant M-500 was used alone (Comparative Example 3) And the mechanical properties are improved as well.

In addition, referring to Tables 8 to 10 above, the improvement in the dry strength and the increase in the paper ash content show similar tendencies. This is interpreted as a result of being placed in the general paper theory in which the paper force is reduced as the paper ash increases, but in the end, the method of agglomerating the paper filler does not apply the improvement of the dry strength to the primary purpose, (By reducing the amount of pulp used) can be interpreted as a phenomenon of evidence that producers can decide whether to use cost reduction for that purpose.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood that various modifications and changes may be made without departing from the scope of the appended claims.

Claims (9)

In the method of pre-agglomerating a filler for paper,
Slurrying two or more kinds of solid mixed fillers; And
During the stirring of the filler slurry, 0.30 to 0.54 parts by weight of the first flocculating agent and 0.06 to 0.30 parts by weight of the second flocculating agent are sequentially added to 100 parts by weight of the two or more kinds of solid mixed filler and the stirring is stopped to form the filler preaggregate &Lt; / RTI &gt;
The first flocculant is an amphoteric polyacrylamide, which is represented by the following general formula (1)
Wherein the second flocculant is an anionic polyacrylamide and is represented by the following formula (2)
Method for agglomerating paper filler.
[Chemical Formula 1]

In Formula 1,
n is a rational number of 0.3 or more and 0.8 or less,
m is the glass number of not less than 0.05 and not more than 0.5.
(2)

In Formula 2,
n 'is a rational number of 0.3 or more and 0.8 or less,
m 'is an glass number of not less than 0.01 and not more than 0.5. The method according to claim 1,
The filler,
Wherein at least two selected from the group consisting of heavy calcium carbonate (GCC), light calcium carbonate (PCC), clay, talc, and titanium dioxide are used. delete delete delete delete The method according to claim 1,
The step of forming the filler pre-
Wherein the first flocculating agent is added while stirring the filler slurry at 800 to 1000 rpm for 5 to 10 seconds, and the second flocculating agent is added after 1 to 5 seconds. delete delete

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