KR100936017B1 - Paper manufacturing method based on the filler preflocculation technology with cationic PAM - Google Patents

Abstract

The present invention relates to a paper manufacturing method using a packing preaggregation using a positive palm (PAM), by adding a cationic PAM having a molecular weight of 1 million to 8 million g / mol and a charge density of 0.1 to 5.0 meq / g Pre-aggregate the filler, check the coagulation phenomenon of the filler by using the filler mixing cell and the particle size analyzer DSD, which reduced the existing DDJ, and adjusts the amount of the amphoteric polymer, the coagulation time and the shear force during the coagulation of the filler The present invention relates to a paper manufacturing method to which filler pre-aggregation using positive PAM is applied, by appropriately adjusting the particle size and distribution of and adding the filler pre-agglomerate to a paper containing pulp to reduce the amount of fiber.

Precoagulation, filler, amphoteric polymer, PAM, whiteness, retention, DDJ, paper, DSD

Description

Paper manufacturing method based on the filler preflocculation technology with cationic PAM}

The present invention relates to a paper manufacturing method using a filler pre-aggregation using a positive PAM, a cationic PAM having a molecular weight of 1 million to 8 million g / mol and a charge density of 0.1 to 5.0 meq / g is added to the filler The present invention relates to a paper manufacturing method to which a packing preaggregation using a positive PAM is applied to agglomerate and add the packing preagglomerate to a paper containing pulp to produce paper in which fiber raw material is reduced.

In general, fillers used in paper making are calcium carbonate, clay, talc, titanium dioxide, etc., which are used in up to 40% of the paper. Fillers improve the paper's opacity, whiteness, smoothness, printability, etc., and are cheaper than pulp, resulting in greater cost savings. However, when the amount of filler in the paper is increased in a general papermaking process, the retention of paper is lowered, and the paper workability is lowered. Therefore, there is an urgent need for a technique that can increase the amount of filler added without deteriorating the physical properties of paper.

An object of the present invention devised to solve the above-mentioned problems is that the filler preagglomerate is determined by particle size and shape through control of the polymer and shear force, so that the aggregation of the filler is performed in a short time in order to optimize the aggregation of the filler. The change of the particle size according to the change is observed in real time to agglomerate the filler to a suitable size to provide a paper manufacturing method applied to the filler pre-aggregation using the positive PAM to increase the content of the filler without reducing the strength of the paper.

In addition, another object of the present invention, when the filler preaggregation technology is applied, the particle size of the filler is increased to increase the retention, the paper to which the filler preaggregation using the positive PAM is applied to reduce the amount of the retention agent for the filler in the papermaking process It is to provide a manufacturing method.

In the paper manufacturing method using the filler preaggregation using the positive PAM according to the present invention, cationic PAM having a molecular weight of 1 million to 8 million g / mol and a charge density of 0.1 to 5.0 meq / g is added to pre-aggregate the filler. Characterized in that the filler preagglomerate is added to the stock containing pulp,
The ratio of filler and cationic PAM is 99.09: 0.01 ~ 99.00: 1.00 (W / W),
Fill the filler with DDJ using a wire with a mesh of a different type and size, add the amphoteric polymer while stirring, and further stir, and after receiving the filtrate in an Erlenmeyer flask, dry it as it is to determine the retention of the filler preagglomerate. It is characterized by checking the particle size of the packing line aggregate by displaying the size of each aggregate by weight,
The stirring speed of DDJ was maintained at 400 rpm. After 20 seconds, the size was increased to 1000 rpm and 1600 rpm to compare the size of the filler preaggregates formed at 400 rpm, 1000 rpm, and 1600 rpm. Characterized in that to check the stability,
It is characterized by using a direct size detector (DSD), an optical instrument, in real time to observe the particle size change according to the injection of the positive polymer and the shear force of the packing preagglomerate,
When the filler is pre-aggregated using a filler mixing cell of a reduced size of the existing DDJ, it is characterized by checking the aggregation phenomenon according to the concentration of the filler.

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According to the present invention as described above, since the filler pre-agglomerate is determined by the control of the polymer and the shear force, the particle size and shape are determined, so that the aggregation of the filler is optimized to change the particle size according to the change of the polymer input and the shear force occurring in a short time. It can be observed in real time to provide a paper manufacturing method applied to the filler pre-aggregation using a positive PAM to agglomerate the filler to a suitable size to increase the content of the filler without reducing the strength of the paper.

In addition, the present invention, when the filling preaggregation technology is applied, the particle size of the filling is increased to increase the retention, the paper manufacturing method applied to the filling preaggregation using a positive PAM that can reduce the amount of the retention agent for the filling in the papermaking process Can provide.

Hereinafter, a preferred embodiment of the paper manufacturing method to which the filler preaggregation according to the present invention is applied will be described in detail.

However, these examples are only for illustrating the present invention specifically, the scope of the present invention is not limited to these examples.

 Fill pre-aggregation technology refers to a technique in which the filler slurry is agglomerated with a polymer material to form agglomerates of an appropriate size and then injected into the stock at a position close to the head box.

Retention degree is the ratio of pulp, fine fibers, fillers, and various chemicals contained in paper stock remaining on the wire to make paper, which is directly related to the economics of the papermaking process.

 DSD is a probe type device that can be inserted directly into the material to obtain the image of the filling in real time. The design principle of the DSD was to eliminate incidental lines and power sources and to make measurements directly in the stock. For this purpose, the lens, sensor, and light receiving image were all inserted into the probe, and the flow of material was taken into the open gap between the lens and the light. In addition, a groove was formed in the surface of the illuminated substructure for smooth flow of the fluid. In order to prevent the error of projected images due to overlapping filling and control between the gaps, diaphragm and micrometer that can control the flow rate and gap are installed, and a progressive scan type CCD is used for image quality.

The final volume in the filler mixing cell was 200 mL and the final concentration of the filler slurry was 20%.

In the present invention, the ratio or% means weight ratio or weight% unless specifically limited.

Experimental Example 1

In order to investigate the particle size analysis of filler aggregates according to the amount of amphoteric polymer, heavy calcium carbonate (GCC, Hydrocarb 75F, Korea Omya Co.) was used as a filler, and 2 types of positive PAMs having different viscosities as positive polymers, and 2 types of positive starches , The experiment was performed using a Fixing agent.

Table 1 shows the properties of the heavy calcium carbonate (GCC), Table 2 shows the properties of the amphoteric polymer.

Average particle size (㎛) ISO whiteness (%) Zeta potential 1.55 96.3 -17.6

Kinds Charge density (meq / g, pH7) Viscosity (cPs, 25 ° C) Positive PAM 1 (low viscosity) 1.36 92.5 (0.1%) Positive PAM 2 (High Viscosity) 1.23 455.0 (0.1%) Positive starch 1 0.21 8.5 (0.5%) Positive starch 2 0.32 280.0 (0.5%) Fixing agent 2.60 7.0 (0.1%)

After filling the filler in DDJ to 0.5%, dispersing well for 20 seconds at a stirring speed of 400 rpm, and then adding a positive polymer during stirring and stirring for 10 seconds further, the filtrate was received in a Erlenmeyer flask and dried as it was to form a packed aggregate. The retention of was calculated, and the size of the aggregates of the packing was expressed by weight. For the analysis of the size of the filler aggregates according to the positive polymer, the level of the amount of each positive polymer was determined based on a wire having a size of 74 μm (200 mesh).

FIG. 1 is a graph showing the amount of aggregates which failed to pass through a 74 μm wire by weight% by using positive PAM and positive starch having different viscosities. The top of the x axis is the amount of addition to the charge of the positive PAM and the bottom is the amount of addition of the positive starch. In both types of positive PAM, 67% had a size of 74 µm or more at 0.05% of the dose, and 70% of the 1.5% of the positive starch had been added. In order to see the change pattern of the packing aggregate in the shear force change state, the positive PAM was determined to be 0.05% and the positive starch was determined to be 1.5%.

Experimental Example 2

When the preaggregation technique is applied, the preaggregator is exposed to strong shear force while passing through the stirrer, the pump and the pipe. The identification of changes in GCC aggregates for these process changes is an essential basis for the development of preaggregation techniques. In order to evaluate the particle size change of the filler aggregates according to the shearing force, a positive polymer was added, the stirring speed was changed, and the residual amount of the mesh was measured using different wires.

GCC and five types of amphoteric polymers mentioned in Table 1 and Table 2 were used to test wires with different meshes for DDJ.

FIG. 2 is a diagram illustrating a particle size evaluation method of a packing pre-aggregate through retention calculation using wires having different mesh sizes and DDJ. FIG.

0.5% of the filling in DDJ was dispersed well for 20 seconds at a stirring speed of 400 rpm, and then the stirring speed was changed to form aggregates by adding 0.05% of GCC and 1.5% of positive starch in the two types of positive PAM. After further stirring for 10 seconds, the filtrate was received in an Erlenmeyer flask and dried as it was to calculate the retention of the packing aggregate.

The change in agitation speed applied when evaluating the particle size change of the packing preagglomerates according to the shearing force was applied at 400 rpm for the first 20 seconds after aggregating GCC into the positive polymer and maintaining the agitation speed at the same 400 rpm, or 1000 to enhance shear force. The test was performed at 1600 rpm.

The low-viscosity positive PAM showed a tendency to decrease aggregates having a size of 75 μm or more and to increase aggregates of 18 μm or less as the stirring speed was increased.

The particle size distribution of the agglomerates with varying agitation speed using high viscosity positive PAM showed that the agglomerates having a size of 75 μm or more decreased and the agglomerates of 18 μm or less increased as the agitation speed increased.

The low viscosity positive starch increased the agitation rate to account for 76% of fine aggregates having a particle size of 18 μm or less.

The high viscosity positive starch decreased the aggregate having a size larger than 74 ㎛ with the increase of the stirring speed, but it decreased to 15% when the fine aggregate having the particle size of 18 ㎛ or less was 1600 rpm. Aggregates with a size of 34 μm increased.

Fixing agent formed small aggregates with more than 96% of less than 18 ㎛ even if 0.3% compared to GCC.

Experimental Example 3

As a result of the above [Experimental Example 2], the aggregated form of the packing according to the positive polymer was evaluated using high viscosity positive PAM and high viscosity positive starch excellent in aggregate formation ability.

After forming agglomerates using high viscosity positive PAM and positive starch 0.05% and 1.5% of GCC, respectively, the filtrate was taken without using wire and diluted 50 times, and analyzed by microscope.

The morphology of the high viscosity positive PAM aggregates was linear, and the microparticles were undifferentiated as the stirring speed increased to 400, 1000 and 1600 rpm.

The agglomerates of cationic starch had a spherical shape and micronization was progressing with increasing stirring speed, but it was relatively less micronized than that of high viscosity positive PAM.

Referring to Figure 3, it is possible to compare the appearance of the aggregates by the positive PAM and the positive starch, in the case of positive PAM having a linear polymer structure is a twisted shape, in the case of branched positive starch aggregates are formed into a spherical shape In the case of starch, the morphological differences of these aggregates are more likely to cause shear forces.

Experimental Example 4

The GCC, two types of positive PAM, and high viscosity positive starch were used to evaluate the coagulation effect according to the packing concentration.

High viscosity positive PAM and positive starch were used at 0.05% and 1.5% of GCC, respectively, according to the concentration of GCC. However, the concentration of GCC was changed to 0.5, 1, and 2%, and a mesh having a size of 34 μm was used as the wire for filtration to best express the change according to the stirring speed.

The change in size of GCC aggregates according to the concentrations and the positive polymers was similar in all three polymers at the agitation rate of 400 rpm at 0.5% GCC concentration. Both cases decreased, whereas those of the positive starch increased.

At agitation speed of 1000 rpm, the size ratio of aggregates of three polymers with GCC concentration decreased with increasing GCC concentration in low viscosity positive PAM, and high viscosity positive PAM increased slightly in positive starch.

When exposed to the highest shear at agitation speed of 1600 rpm, the size of aggregates was the largest in the case of cationic starch, and slightly increased in the case of two types of cationic PAM.

Experimental Example 5

It was found that the preaggregated fillers were determined to have a particle size and shape through control by polymer and shear force. In order to optimize the coagulation of the packing, it is necessary to be able to observe the change of particle size due to the change of shear force and the polymer loading occurring in a short time. In addition, these measuring devices should be able to obtain particle size data with a buffer against local flow and concentration changes.

We developed a direct size detector (DSD) that can be inserted directly into the material as a probe type to obtain an image of the filling in real time, and applied it to the experiment to analyze the effect of preaggregation. DSD is an optical method that can be used to evaluate the size and variation of filler aggregates online, which is suitable for analyzing the effect of the filler preaggregation process.

4 is a diagram illustrating a design diagram of a DSD.

GCC was added to DDJ to make 0.5%, dispersed at a stirring speed of 400 rpm, and then positive polymer was added thereto. The dose was 0.04% for positive PAM and 0.6% for positive starch. At the same time as adding the polymer, the stirring speed was changed to 800, 1000, 1200, and 1400 rpm, respectively, and 50 images were obtained from 30 seconds to 250 seconds without image change.

In the case of using positive PAM, the average area of the aggregates decreased with increasing agitation speed, and tended to decrease with time, but the slope gradually decreased.

The change in the standard deviation of the packing agglomerates with agitation speed and time was decreased with increasing agitation speed when positive PAM was used, indicating that the distribution of the area was narrowing with increasing agitation speed.

From the area distribution, deviation and histogram of the aggregates obtained in the above experiments, it was confirmed that the particle size of the filler preaggregates formed by the positive PAM can be controlled when the shear force intensity and time are adjusted in parallel.

Experimental Example 6

In the field, the filling is supplied to the paper machine at approximately 60% from the supplier and diluted to 20-30%. [Experimental Example 1] to [Experimental Example 5] was evaluated by pre-agglomeration effect of the packing according to the concentration of the filler due to the pre-aggregation of the filler at a very low concentration of 0.5% of the filler, but from the [Experiment 6] The experiment was carried out by raising the concentration of the charge to 20% to get closer results.

For the test material, heavy calcium carbonate (GCC, Hydrocarb 75F, Korea Omya Co.) was used as the filler, and high viscosity positive PAM and positive starch were used as the polymer for preaggregating the filler.

5 is a view showing a schematic diagram of a filler mixing cell. A filler mixing cell of a reduced form of DDJ was prepared as shown in FIG. 5. The final volume in the filler mixing cell was 200 mL and the final concentration of the filler slurry was 20%. The size and distribution of packing preagglomerates were evaluated by adjusting the dosage of the polymer and the stirring speed at the time of loading. Particle size analysis of the packing preagglomerate was evaluated by administering the amphoteric polymer while the packing was stirred, adding 30% of the mixture to DDJ, diluting it to 0.5%, and immediately obtaining an image using DSD and performing image analysis. It was. After dilution to 0.5%, the coagulation particle size in DDJ remained constant over time. FIG. 6 is a diagram illustrating a particle size analysis of a packing preaggregator using a DSD. FIG.

 The size of the filler preagglomerate was found to be more affected by the polymer input than the stirring speed. The standard deviation of the linear aggregate particle size was smaller as the stirring speed was increased and as the amount of polymer injected was smaller. In terms of polymer dosage, cationic starch requires more than 15 times the input amount to obtain aggregates similar in size to the positive PAM. Also, among aggregates of the same size formed by positive starch and positive PAM, the linear aggregate formed by positive starch showed less change in particle size for shear force than the linear aggregate formed by positive PAM.

 The standard deviation of the linear aggregate particle size was smaller as the stirring speed was increased and as the amount of polymer injected was smaller. As the stirring speed increases, the standard agglomerate value decreases because the linear agglomerate becomes smaller due to the shear force and becomes uniform. In addition, as the amount of the polymer input increases, the size of the linear aggregate increases, so that the size difference between the filler and the linear aggregate that does not form an aggregate is large, and thus the standard deviation value becomes larger. In general, positive starch tended to form relatively uniform aggregates compared to positive PAM.

Experimental Example 7

In order to evaluate the physical properties of the paper according to the application of the preagglomerate, papermaking experiments were performed using the preaggregation filler.

The stock was prepared by beating HW-BKP using laboratory valley beater to be 440 ~ 460 mL CSF in Yeosu based on TAPPI Test Methods T 200 sp-96. The final concentration was 0.5%. It was.

After filling the polymer into the filler mixing cell, the polymer was added to make the preagglomerate, and after 30 seconds, the pipette was used to make 20, 30, 40, 50% of the total fiber by using a pipette to the stock being stirred at 600 rpm. Aggregates were added. After stirring again for 30 seconds, a resin paper was prepared to have a basis weight of 90 g / m ² . In general, the nozzle of the pipette tip was about 2 mm in diameter, but in this experiment, the diameter of the pipette tip was expanded to 4 mm or more for smooth injection of the linear aggregate. The sheet was pressed and dehydrated at 3.5 kg / cm ² for 5 minutes in a press and then dried in a 120 ° C. cylinder dryer for 1 minute. The dried paper was subjected to humidity treatment for 24 hours at 23 ° C. and 50% RH in a constant temperature and humidity condition, and then ash content, tensile strength and whiteness were measured according to the TAPPI test method.

The retention of fillings was higher than that of the conventional method in the case of positive PAM in all doses with the filling preaggregation technique. In this experiment, no retention agent was added to hold the preagglomerate. However, the application of the filler preaggregation technique is expected to reduce the use of the preservatives for the fillers in the papermaking process because the particle size increases and the retention increases. .

Tensile strength showed higher tensile strength than conventional paper-made papers when the filler content of paper was the same. The higher the filler content of the paper, the more pronounced the tensile strength improvement by preaggregation was. If the paper requires a certain strength, it means that the content of the filler can be increased by applying the preaggregation technique of the filler.

As the filler content increased, the whiteness of the paper increased linearly. However, the application of preaggregation technology, in contrast to the improvement of the strength properties, in the case of the optical properties, the rise of the phenomenon rather decreased. The whiteness of the pasture paper with filler preagglomeration was relatively low at all doses. However, the application of filler preaggregation to produce paper with a constant tensile index can increase the content of the filler, which increases the effect of offsetting the whiteness degradation caused by the application of preaggregation technology. Little change in whiteness.

In addition, in order to evaluate the physical properties of the paper according to the size of the line aggregate, the polymer retention amount was changed to compare the retention, tensile strength and whiteness under the conditions shown in Table 3.

0.02% 3000 rpm 0.04% 2000rpm 0.06% 2000rpm Average particle size (㎛) 28 40 51 Standard Deviation 44 63 84

7 is a view showing the filler content of the paper according to the filler input amount when the size of the linear aggregate is different. The charge retention increased as the average size of the preagglomerate increased with different polymer inputs.

8 is a diagram showing the tensile index and the whiteness according to the filler content of the paper when the size of the line aggregate is different. Referring to Figure 8, Figure 8 (a) shows the tensile strength of the paper. Tensile strength improved as the average size of the linear aggregate increased, but there was no difference between the average particle size of 40 ㎛ and 51 ㎛. However, (b) of FIG. 8 shows whiteness. As the average size of the linear aggregate increases, the whiteness decreases. From the above results, it can be seen that if the filler is agglomerated to an excessive size in order to increase the filler content of the paper, a problem of lowering the whiteness may occur as the size of the aggregate increases, rather than improving the strength. Therefore, in order to improve the physical properties of the paper by applying the filler pre-aggregation technology, it is judged that it is very important to aggregate the filler to the appropriate size.

The present invention is not limited to the above-described preferred embodiments and can be easily modified by anyone of ordinary skill in the art without departing from the gist of the invention claimed in the claims, Such changes are intended to fall within the scope of the claims.

1 is a view showing a GCC aggregate content of more than 74㎛ according to the amount of the positive polymer according to an embodiment of the present invention

FIG. 2 is a diagram illustrating a particle size evaluation method of a packing pre-aggregate through retention calculation using wires having different mesh sizes and DDJ. FIG.

Figure 3 is a view showing the appearance of aggregates by positive PAM and positive starch according to an embodiment of the present invention

4 is a diagram showing a design diagram of a DSD;

5 is a view showing a schematic diagram of a filler mixing cell

6 shows particle size analysis of packing aggregates using DSD.

7 is a view showing the filler content of the paper according to the filling amount when the size of the pre-aggregate is different

8 is a view showing the tensile index and the whiteness according to the filler content of the paper when the size of the line aggregate is different.

Claims (6)

Cationic PAM having a molecular weight of 1 to 8 million g / mol and a charge density of 0.1 to 5.0 meq / g is added to pre-aggregate the filler, and the filler pre-agglomerate is added to the paper containing pulp. and, The ratio of filler and cationic PAM is 99.09: 0.01 ~ 99.00: 1.00 (W / W), Fill the filler with DDJ using a wire with a mesh of a different type and size, add the amphoteric polymer while stirring, and further stir, and after receiving the filtrate in an Erlenmeyer flask, dry it as it is to determine the retention of the filler preagglomerate. It is characterized by checking the particle size of the packing line aggregate by displaying the size of each aggregate by weight, The stirring speed of DDJ was maintained at 400 rpm. After 20 seconds, the size was increased to 1000 rpm and 1600 rpm to compare the size of the filler preaggregates formed at 400 rpm, 1000 rpm, and 1600 rpm. Characterized in that to check the stability, It is characterized by using a direct size detector (DSD), an optical instrument, in real time to observe the particle size change according to the injection of the positive polymer and the shear force of the packing preagglomerate, The method of manufacturing paper with filler pre-aggregation using positive PAM characterized in that when the filler is pre-aggregated using a filler mixing cell which is a reduced production of existing DDJ, the coagulation phenomenon according to the concentration of the filler is confirmed. delete delete delete delete delete

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