KR20000019286A - Process for composing raw material of paper - Google Patents

Abstract

PURPOSE: A process for composing a paper raw material is provided to quickly cope with the state of waste paper or of other virgin pulp and the property change of matter by an appropriate use of the paper force reinforcing agent. CONSTITUTION: A process for composing a paper raw material contains the processes of: untying a waste paper by putting in a pulper; selecting and concentrating thereof; mechanically preprocessing the concentrated fiber; increasing a binding thereof; and mixing with a virgin pulp passed a separate binding increasing process. In the mechanical preprocessing process, the fiber is minutely compressed by adding the compressing force and the shearing force into the fiber so a curled index as to be over 0.03 of binding increasing curled index under the preprocessing condition of 15-35% preprocessing entrance concentration and of the exit temperature of 25°C.

Description

Feedstock creation process

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper (paper raw material) composition process, and more particularly to a paper composition process for improving the physical properties of waste paper to increase the mixing ratio of waste paper.

Generally, there are two kinds of raw pulp used in the manufacture of paper, virgin pulp and waste paper. Among these, virgin virgin pulp is pulp that has never been used to make paper directly from wood. Pulp used for.

Since Korea does not have enough wood, virgin pulp or waste paper (eg corrugated waste paper, newspapers, etc.) is imported from abroad, especially waste paper is imported because it is cheaper than the price of virgin pulp. Is significantly lower than virgin pulp, and the problem of dehydration is raised in the papermaking process due to the increase of fine fiber fraction.

Therefore, in the papermaking field, many studies have been conducted to increase the content of waste paper while maintaining the strength of industrial paper (eg kraft paper, liner paper, corrugated paper, white paper, special paper, etc.) in order to reduce production costs during paper manufacturing. It is becoming.

In the production of such industrial paper, its physical and chemical properties depend on the chemicals mixed with the mixing ratio of virgin pulp and waste paper, which take up most of the manufacturing process, and the treatment process thereof.

In the papermaking process, virgin pulp and waste paper are prepared as raw materials and put into pulp to be first released.Then, after the selection-selection-process, the beating process is performed to improve the strength and bonding strength. It is made of paper through a process of drying, foundation, and winding.

In this case, proper physical and chemical treatment is required in the process of forming the raw material to satisfy the required physical properties of the paper, and suitable equipment and operation methods are provided in a process such as proper concentration, manufacturing speed, and dehydration drying in the paper manufacturing process.

In the existing papermaking process, proper processing in the raw material composition process has been repeated a series of simple operations to simply adjust or adjust the blasting conditions in order to remove this substance mixed in the raw material or to improve the binding force and operation. Intellectual enhancers were used to increase the mixing ratio of waste paper.

For example, the quality characteristics required for kraft paper, one of the industrial papers, require not only the tensile strength required for processing the product, but also tear strength and impact strength that can be torn or impacted when storing contents.

However, the increase in altitude for the improvement of tensile strength entails a decrease in tear strength, so it is necessary to increase the waste paper while maintaining the balance of the two strengths.

If we increase the waste paper blending ratio of Kraft Paper by 20%, the tensile strength and tearing strength are both required to be increased by more than 10% to maintain the quality before increasing the content of waste paper.

In order to solve this problem, conventional techniques have been applied to increase the tear strength by applying curl to the fiber through the Frotapulper to increase the elongation of the paper, and to improve the tensile strength by using the strength enhancer chemicals.

However, the excessive use of the strength enhancer not only increases the production cost of the product but also causes an increase in tensile strength, which causes a problem that the tear strength decreases.

The present invention was created to solve the problems described above, it is possible to maintain and improve the strength properties while increasing the mixing ratio of waste paper, and to provide a method for forming a paper material that can minimize the use of the strength enhancer. There is this.

In order to achieve the above object, the present invention, the process of releasing waste paper in the pulper, the process of selecting and concentrating it, the process of physical pretreatment of the concentrated fiber, the process of beating it, and a separate beating process In the material composition process comprising the step of mixing with the virgin pulp passed through,

In the physical pretreatment of the fiber, under the pretreatment conditions of 15 to 35% of the pretreatment inlet concentration and the outlet temperature of 25 ° C. or more, the compressive force and the shear force are applied to the fiber such that the curl index of the fiber is 0.03 or higher than that before the physical pretreatment. It provides a stock composition process characterized in that the fine compression of the fibers.

1 is a reference diagram schematically illustrating the definition of curl.

2 is a process chart showing a first embodiment of a stock composition process according to the present invention.

Figure 3 is a process chart showing a second embodiment of the stock composition process according to the present invention.

<Description of the code | symbol about the principal part of drawing>

L: Fiber Length ℓ: Curl Fiber Length

2 is a process chart showing a first embodiment of a stock composition method according to the present invention, Figure 2 is a process chart showing a second embodiment of a stock composition process according to the present invention.

As shown in FIG. 2, a first embodiment of the paper material forming process according to the present invention includes a process of primarily releasing waste paper into a pulp, a selection process of filtering foreign matter contained in regenerated fibers released in the process; The process of concentrating the selected recycled fiber, the physical pretreatment of the concentrated recycled fiber, the beating process to improve the strength and bonding strength of the physically pretreated regenerated fiber, and the beating process separately from the regenerated fiber Mixing with virgin pulp to form papermaking.

As shown in FIG. 3, the second embodiment of the material composition process according to the present invention includes a long fiber and a short fiber in the regenerated fiber through a selection device after performing a process of primarily releasing waste paper into a pulp. Among them, the long fibers are subjected to the concentration-physical pretreatment-beating process, and the short fibers are subjected to the concentration-beating process through another route, and then the long fiber of the waste paper and the short fibers and virgin pulp are mixed in the mixing tank. The mixture is fed to the paper machine.

In the present invention, the physical pretreatment process is improved among the processes described above, and the regenerated fiber is concentrated by applying a strong physical compressive force and shear force in the physical pretreatment process to the regenerated fiber concentrated through the concentration process, thereby increasing the flexibility of the regenerated fiber and By removing the stiffness of the fiber and at the same time by applying the compressive force and the shear force to form curls in the recycled fiber to increase the elongation and impact absorption of the paper produced by the treatment process to reduce the quality of the recycled fiber It proposes a process that increases the content and minimizes the use of strength enhancers, while maintaining the strength characteristics of existing paper.

In the present invention, for example, frotapulper, curlator, screw press, dispersor, kneader, etc. are used as a machine capable of maintaining the length of the fiber while applying strong compressive force and shear force to the fiber. Since the degree of curling, the curling and the flexibility of the accompanying fiber, and the treatment after curling are important keys in improving and improving the properties of the fiber, the present invention focuses on this, and thus, specific curling and post-treatment processes By designating this, the results of improving the physical properties of waste paper will be presented.

The present invention focuses on reducing the stiffness of the fibers commonly occurring in the regenerated fibers and increasing the flexibility of the fibers by applying the microcompression of the regenerated fibers by applying the strong compressive force and the shear force to the regenerated fibers in the physical pretreatment process.

And the regenerated fiber subjected to the physical treatment as described above is to increase the elongation of the paper made from such regenerated fiber by increasing the binding capacity of the fiber through beating, and to make the inter-fiber bond strong.

The curling degree of the fiber at the time of high fiber of this fiber is the same as or slightly larger than that of the curl after the non-physical pretreatment, but the fiber elongation is very large, resulting in an increase in the elongation and tear strength of the paper using the fiber. do.

In the present invention, a new treatment process was developed by comparing the physical properties of the raw materials currently used by the company through a series of treatment processes. This is the development of a treatment process that overcomes the limitations of existing methods as a result of improving the properties that could not be solved while processing raw materials. The raw materials used in this study were waste paper used in our company, and paper was prepared by mixing virgin pulp at a constant ratio.

Table 1 below summarizes the types and compounding ratios of raw materials used during process development.

division Pulp Type Virgin Pulp abolition Standard compounding ratio (%) 60 40 Development mix ratio (%) 40 60

In the present invention, the criterion of the physical pretreatment of regenerated fibers was determined by the curl index. The definition of the curl index is as shown in FIG.

Regardless of the treatment concentration of the regenerated fiber or the treatment temperature, an increase in the curl index by physical pretreatment at room temperature (20 ° C.) indicated the degree of physical treatment.

The cul- ture index was measured using a Fiber Quality Analyzer and the length-weighted average was taken.

Applicant examined the change of paper physical properties by performing the beating treatment of the blending ratio, the physical treatment of the fibers (curls, compression and shearing), and the use of the strength enhancer step by step as the first step of the process.

In the physical treatment, mechanical treatment was performed while maintaining the inlet concentration of 20 to 30% and the temperature of 25 to 30 ° C to simultaneously generate micro-compressions of curls and fibers.

The pulp was not curled. The raw material thus treated was subjected to beating treatment, and the material composition process is shown in FIG. 2, and the conditions using the strength enhancers were also examined to compare with the existing material composition method. The experimental results are shown in FIG.

division standard One 2 3 4 Compounding cost Virgin Pulp (%) 60 40 40 40 40 abolition(%) 40 60 60 60 60 Confession enforcement radish radish enforcement enforcement Physical treatment (curl, compression, shear) radish enforcement enforcement enforcement enforcement High Resolution Battle Paper Index 0.110 0.150 0.150 0.150 0.150 After the confession abolished the Curl Index 0.06 0.150 0.150 0.125 0.125 Intellectual enhancer (3%) radish radish enforcement radish enforcement Bedding (km) 5.24 4.48 5.21 5.54 5.78 Tear index 136 147.84 138.4 139 132 Elongation (%) 2.77 3.30 3.50 3.36 3.05 Increase vs Standard The tensile strength -14.5% -0.6% + 5.7% + 10.3% Tear strength + 8.7% + 1.8% + 2.2% -2.9% Elongation + 19.1% + 26.4% + 21.3% + 10.1%

* Weight-weighted average = 2.774 mm

In Table 2, stock No. 3 showed higher physical properties than the standard without the use of drugs. However, physical pretreatment increased the high resolution curl index by 0.04.

In the second step, experiments were conducted to investigate the effect of fiber length and physical treatment concentration of recycled fibers on the curl index of recycled fibers and the physical properties of paper.

The fiber length of 1.6 mm of Table 3 is obtained from domestic liner paper factory, and the 2.4 mm fiber is corrugated paper waste obtained from domestic kraft paper production plant.

As a result of physical pretreatment with varying concentrations from 17% to 27%, the curl index indicating the effect of physical treatment of corrugated paper was increased about 0.04 for long fibers (2.4mm), but short fibers ( 1.6mm), the curl index increase was less than 0.03.

When the physical properties of these fibers were examined, the long fibers showed a significant increase in tensile retention and tear, and short fibers showed a significant drop in tear.

Therefore, this process shows that it is possible to maintain the tensile strength and tearing strength when physical pretreatment is performed so that the fiber length of 1.6 mm or more is increased to 0.03 or higher. Considering the factor, the fiber length should be maintained at 2.0 mm or more.

In addition, since the maximum length of the corrugated paper waste paper is generally about 2.8 mm level, it is preferable that the corrugated paper waste paper fiber condition is set to 2.0 to 2.8 mm.

Fiber sheet (cardboard abolition) 1.6mm 2.4mm Pretreatment concentration control 17% 21% 27% control 18% 23% 27% Physical pretreatment radish Pretreatment Pretreatment Pretreatment radish Pretreatment Pretreatment Pretreatment High resolution battle index 0.075 0.092 0.100 0.110 0.105 0.152 0.148 0.168 Corrugated cardboard high weather thermal insulation 60% / 40% pulp / cardboard waste paper 4.48 5.24 40% / 60% pulp / cardboard waste 4.38 4.68 4.35 5.40 5.44 5.33 Corrugated Cardboard High Tear Tear Index 60% / 40% pulp / cardboard waste paper 118.0 134.8 40% / 60% pulp / cardboard waste 111.0 110.2 121.2 135.5 139.0 138.0

* After confessing the cardboard waste paper to the same Yeosu, mix it with pulp and make a paper sheet to measure the physical properties.

In addition, when the fiber length is 2.0 to 2.8mm, the average curl index of physical pretreatment condition is 0.09 ~ 0.12, and curling is formed by compression and shear force after physical pretreatment. can do.

As shown in Table 3, the concentration range required for pretreatment shows sufficient curling effect even at 18% concentration when the fiber length is 2.4mm. It is preferable to set.

In the temperature range required for pretreatment, the temperature selected in the experiment in Table 3 was achieved at 25 to 30 ℃, and the white paper temperature of the general papermaking process exceeded 25 ℃ even in winter. It does not have to be set, but the higher the temperature, the more advantageous aspects of the curling effect of the fiber, but it requires steam consumption separately, so if you set an additional target will need to be considered separately.

As the third step of the process, the change of the curl index according to curling and beating treatment is shown in Table 4.

division Confession Curl index Elongation (%) Bedding (km) Tear index Do not curl Never 0.100 2.07 2.57 120.5 Do not curl 10 minutes 0.054 2.40 4.98 130.6 Do not curl 20 minutes 0.046 2.45 5.63 130.1 Do not curl 30 minutes 0.043 2.45 6.39 128.9 Curling box Never 0.149 2.44 2.36 125.7 Curling box 10 minutes 0.062 2.88 4.76 150.1 Curling box 20 minutes 0.050 2.59 5.62 143.2 Curling box 30 minutes 0.040 2.67 6.87 134.3

The high resolution curl index showed a significant difference, but there was no significant difference in the high index curl index. However, the fibers pre-treated at high resolution still exhibited an increase in physical properties (especially tear strength) even under the non-numeric curl index.

From the above, the stock composition process we developed can be summarized as follows.

The high index curl index cannot be an absolute criterion for increasing the tear strength, but the high index curl index can be a measure of how much compression and shear strength the fiber receives. This is outstanding for 10 minutes of confession, but it is 0.062 and 0.052 in curled and untreated, respectively, but it does not show a large difference in thermal length and shows a large difference in tear strength of 130 and 150.

When curling the raw material and making paper, the density of the paper decreases, the thermal shortening of the paper decreases, and only the tear strength is sharply increased. When the fiber is sufficiently beaten, the thermal shortening of the paper is restored and the tear strength of the paper is also increased. The micro-compression action produced by the compressive and shear forces of the fibers improves the flexibility by mechanically softening the raw materials and increases the elongation of the fibers under similar curl index.

As described above, according to the present invention material composition process, it is possible to increase the waste paper compounding ratio while maintaining a certain strength level of the industrial paper and to reduce the use of the strength enhancer to minimize the cost and enhance the product competitiveness It becomes possible.

In addition, if the amount of waste paper is fixed and treated in the same manner, the paper properties can be increased, and the workability can be improved by securing the ability to promptly cope with changes in the state and the properties of waste paper or other virgin pulp through the proper use of the curl index. To contribute.

Claims (2)

It includes the process of releasing waste paper into the pulp, the process of selecting and concentrating it, the physical pretreatment of the concentrated fiber, the process of beating it, and mixing it with the virgin pulp which has undergone a separate beating process In the material composition process, In the physical pretreatment of the fiber, under the pretreatment conditions of 15 to 35% of the pretreatment inlet concentration and the outlet temperature of 25 ° C. or more, the compressive force and the shear force are applied to the fiber such that the curl index of the fiber is 0.03 or higher than that before the physical pretreatment. A material composition process comprising finely compressing fibers. The papermaking process according to claim 1, wherein the waste paper has a fiber length of 2.0 to 2.8 mm.