KR102583061B1 - Paper Comprising Calcium Carbonate From the Shell and Manufacturing Method of the Same - Google Patents

Abstract

The present invention relates to paper containing calcium carbonate shell and a method for producing the same. More specifically, it relates to preparing pulp stock by beating pulp and then diluting it, and mixing the prepared pulp stock and calcium carbonate shell to make a mixture. and a method for producing paper containing shell calcium carbonate, including the step of molding the mixture into paper, pressing, dehydrating, and drying the mixture, and the paper produced thereby.

Description

Paper Comprising Calcium Carbonate From the Shell and Manufacturing Method of the Same}

The present invention relates to paper containing calcium carbonate shell and a method for producing the same. More specifically, it relates to preparing pulp stock by beating pulp and then diluting it, and mixing the prepared pulp stock and calcium carbonate shell to create a mixture. and a method for producing paper containing shell calcium carbonate, including the step of molding the mixture into paper, pressing, dehydrating, and drying the mixture, and the paper produced thereby.

Despite the low self-sufficiency rate of pulp at around 20%, the domestic paper industry is making great efforts to rank 7th in production in the world as of 2021. However, the national competitiveness of the domestic paper industry is decreasing due to the recent rise in dry energy prices and instability in pulp supply and demand. There are concerns about a decline.

In order to overcome the difficulties of the paper industry in these domestic and international environments, a new concept of papermaking technology is required to overcome the limitations of the industry's high consumption of lignocellulosic resources, water, and energy. In particular, cardboard, which accounts for more than 50% of the domestic paper industry's production, is required. The development and application of new eco-friendly papermaking technology is required in the production process.

Recycled pulp is mainly used in the domestic cardboard production process. Recycled pulp has a very high microfiber content, so more raw materials are consumed to achieve the target basis weight, and drying energy is increasing due to decreased dewaterability. In addition, looking at the variable costs in the domestic cardboard production process, the cost of raw material pulp and drying energy accounts for more than 70%, so there is an urgent need to develop technology to reduce raw materials and drying energy.

Meanwhile, precipitated calcium carbonate is an inorganic filler that is actively used in printing paper to improve bulk, stiffness, and whiteness, but in cardboard, inorganic filler is not used because optical properties are not an important quality.

It is judged that the application of calcium carbonate filler to cardboard is required to increase the mineral content along with the increase in bulk. However, when calcium carbonate is added to paper, the strength characteristics of the paper decrease, so the strength decreases at the same time as calcium carbonate filler is applied. Technology development is needed to prevent this.

Accordingly, the present invention developed a paper manufacturing method that can improve the strength of paper and lower the manufacturing cost while increasing the mineral content using calcium carbonate derived from shells.

Korean Patent Publication 10-1094545 B1

The present invention is intended to solve the problems of the prior art as described above, and aims to develop paper that can increase the mineral content, improve the strength of the paper, and reduce the manufacturing cost by using calcium carbonate derived from shells. .

In order to achieve the above object, the present invention includes the steps of preparing a pulp stock by beating and then diluting the pulp, making a mixture by mixing the prepared pulp stock and shell calcium carbonate, and forming the mixture into a paper form, pressing and A method for producing paper containing shell calcium carbonate comprising the step of dehydrating and then drying is provided. It is characterized in that the content of shell calcium carbonate in the mixture is 5 to 20 parts by weight.

Additionally, in order to achieve the above object, the present invention provides paper containing shell calcium carbonate produced by the above-described method. At this time, the basis weight is preferably 80 to 85 g/m2 and the bulk is preferably 1.7 to 2.0 cm3/g, the tensile strength is preferably 30 to 50 kN/m, and the stiffness is preferably 1.4 to 1.6 mN.

The paper of the present invention is not only environmentally friendly by utilizing shell calcium carbonate, but can also increase the inorganic content, resulting in increased bulk and reduced drying energy. In addition, the decrease in paper strength can be minimized and the manufacturing cost can be lowered.

Hereinafter, the present invention will be described in detail with reference to embodiments of the present invention and drawings. These examples are merely presented as examples to explain the present invention in more detail, and it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples. .

Additionally, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains, and in case of conflict, this specification including definitions The description will take precedence.

In order to clearly explain the proposed invention in the drawings, parts unrelated to the description have been omitted, and similar reference numerals have been assigned to similar parts throughout the specification. And, when it is said that a part "includes" a certain component, this means that it does not exclude other components, but may further include other components, unless specifically stated to the contrary. Additionally, “unit” as used in the specification refers to a unit or block that performs a specific function.

The identification codes (first, second, etc.) for each step are used for convenience of explanation. The identification codes do not describe the order of each step, and each step does not clearly state a specific order in context. It may be carried out differently from the order specified above. That is, each step may be performed in the same order as specified, may be performed substantially simultaneously, or may be performed in the opposite order.

The paper of the present invention includes the steps of preparing a pulp stock by beating and then diluting the pulp, mixing the prepared pulp stock with calcium shell to create a mixture, and molding the mixture into a paper form, pressing and dehydrating it, and then drying it. It is manufactured through. At this time, the content of shell calcium carbonate in the mixture may vary depending on the thickness of the paper and other added ingredients, and is preferably 5 to 20 parts by weight.

The paper containing shell calcium carbonate of the present invention is characterized by increasing the content of inorganic components, thereby increasing the bulk and reducing drying energy, while minimizing the decrease in paper strength. Specifically, the basis weight is 80 to 85 g / ㎡ and the bulk is 1.7. It is preferably ~2.0 cm3/g, the tensile strength is preferably 30~50 kN/m, and the stiffness is preferably 1.4~1.6 mN. In addition, the whiteness is preferably 84 to 87% and the opacity is preferably 89 to 92%.

The shell calcium carbonate may be a variety of commercially produced shell calcium carbonates, but preferably, shell calcium carbonate obtained by pulverizing the shell and then calcining may be used to remove impurities and increase dispersibility and porosity.

In addition, in order to increase the filling properties, in a preferred embodiment, two types of shell calcium carbonate can be mixed and used. In one embodiment, the first shell calcium carbonate that has undergone a firing process and the second shell calcium carbonate that has gone through a crystallization process are used in a mixture of 1 ~ It can be mixed and used at a weight ratio of 2:2 to 1, and more preferably, it can be mixed at a weight ratio of 1:1.

Specifically, the first shell calcium carbonate is obtained by grinding the shell; And it can be manufactured through a step of baking the pulverized shell at 300°C to 800°C while stirring. At this time, in the pulverizing step, the shells are pulverized to an average diameter of 5 to 10 mm, and in the firing step, the pulverized shells are powdered to an average diameter of 100 to 500 μm.

The second shell calcium carbonate includes a crushing step of crushing the shell; Calcining the pulverized shell at 800°C to 1000°C while stirring; Preparing an aqueous calcium nitrate solution by adding calcined shell powder to a nitric acid solution; Growing calcium carbonate crystals by mixing the aqueous calcium nitrate solution, the aqueous sodium carbonate solution, and the aqueous lysine solution while stirring; and filtering the grown calcium carbonate crystals and then washing and drying them.

The concentration of the sodium carbonate is preferably 0.01 to 1M, and the lysine aqueous solution is preferably prepared by dissolving lysine in distilled water at a mole number of 0.001 to 0.1 times the mole number of the calcined shell. In addition, it is preferable that the reaction temperature during crystal growth is 10 to 40°C and the stirring speed is 300 to 1500 rpm. The calcium carbonate crystals prepared in this way are circular with an average diameter of 1 to 25㎛ and have high dispersibility.

Hereinafter, the configuration of the present invention and its effects will be described in more detail through specific manufacturing examples and examples. However, these examples are for illustrating the present invention in more detail, and the scope of the present invention is not limited to these examples.

<Manufacturing example>

(1) Preparation of raw materials: Softwood bleached kraft pulp (SwBKP) and hardwood bleached kraft pulp (HwBKP) were beaten using a laboratory valley beater so that each had a freeness level of 450 ± 10 mL CSF, and SwBKP and HwBKP were beaten at 2 The final pulp stock was prepared by mixing at a ratio of :8 and diluting to a concentration of 0.5%.

(2) Paper (waterweed paper) production: To measure the physical properties of waterweed paper according to filler input, waterweed paper with a basis weight of 80±4 g/m ² was manufactured according to TAPPI Standard Method T205.

(3) Manufacturing of aquatic paper

The water paper was manufactured so that the sum of the mass of the pulp and the mass of the filler was 5.26 g, and the amount of mixed pulp (softwood pulp + hardwood pulp) and filler added according to the amount of calcium carbonate added is shown in Table 1 below.

* Basis weight 80 g/m ² (basis weight definition: total weight of paper per unit area), total dry weight: weight measured after completely drying the paper in a constant temperature dryer, area of watered paper = 25 cm × 25 cm, considering moisture content of 5% => 80 g/m ² × 0.25 m × 0.25 m × 0.95 = 4.75 g

Calcium carbonate dosage Input amount for each raw material pulp filler 0% 4.75g 0g 5% 4.75 × 100 ÷ (100+5) = 4.52 g 4.75 × 5 ÷ (100+5) = 0.23 g 10% 4.75 × 100 ÷ (100+10) = 4.32 g 4.75 × 10 ÷ (100+10) = 0.43 g 15% 4.75 × 100 ÷ (100+15) = 4.13 g 4.75 × 15 ÷ (100+15) = 0.62 g 20% 4.75 × 100 ÷ (100+20) = 3.96 g 4.75 × 20 ÷ (100+20) = 0.79 g

<Experimental example>

As shown in the table below, each physical property was measured for each item using a standard measurement method. After analyzing each physical property 10 times on 5 sheets manufactured for each amount of light calcium carbonate, the average and standard deviation were measured and shown in Table 3 below. The ash content was measured three times in three groups by collecting 10 samples and presenting the average.

As can be seen from the table above, it was found that sufficient physical properties could be secured even when shell calcium carbonate was used, and there were no problems with product processability. In addition, the use of recycled calcium carbonate is believed to be more environmentally friendly and cost-saving.

Although the present invention has been described in relation to the preferred embodiment as mentioned above, the technical idea of the invention is not limited or restricted thereto, and of course, it can be modified and implemented in various ways by those skilled in the art.

Claims (5)

preparing pulp stock by beating and then diluting the pulp; Mixing the prepared pulp material and shell calcium carbonate to create a mixture; and forming the mixture into a paper form, pressing and dehydrating the mixture, and then drying it.
The content of shell calcium carbonate in the mixture is 5 to 20 parts by weight,
The shell calcium carbonate is a mixture of first shell calcium carbonate and second shell calcium carbonate in a weight ratio of 1 to 2:2 to 1,
The first shell calcium carbonate is obtained by crushing the shell; and baking the pulverized shell at 300°C to 800°C while stirring,
The second shell calcium carbonate is obtained by grinding the shell; Calcining the pulverized shell at 800°C to 1000°C while stirring; Preparing an aqueous calcium nitrate solution by adding calcined shell powder to a nitric acid solution; Growing calcium carbonate crystals by mixing the aqueous calcium nitrate solution, the aqueous sodium carbonate solution, and the aqueous lysine solution and stirring at 10-40°C; and filtering the grown calcium carbonate crystals and then washing and drying them. delete delete delete delete