KR20200074477A - Manufacturing method of cotton pulp and cotton pulp thereof - Google Patents

Abstract

The present invention relates to a cotton pulp manufacturing method containing cotton fibers and a cotton pulp manufactured by the method. The present invention relates to a manufacturing method using a hydrogen peroxide stabilizer used in a bleaching process as an organic stabilizer having low ash content. The cotton pulp manufacture by the manufacturing method has low ash content and an improved degree of polymerization, so that high-quality cotton pulp can be obtained.

Description

MANUFACTURING METHOD OF COTTON PULP AND COTTON PULP THEREOF}

The present invention relates to a method for producing a cotton pulp comprising cotton fibers and a cotton pulp produced by the method, and to a method for using a hydrogen peroxide stabilizer used in the bleaching process as an organic stabilizer having a low ash content.

Cellulose is a representative polymer derived from natural products, and is used for various purposes. Cellulose can be collected from non-wood plants such as wood or cotton, but when obtained from cotton rather than wood, cellulose has a high content. Wood is composed of 40 to 60% cellulose, while cotton is more than 90% cellulose. Pure cellulose is called alpha-cellulose, and alpha-cellulose content of 98% or more is used for chemical purposes, i.e., for the production of regenerated fibers or cellulose derivatives, and the content of cellulose is significantly higher than that of wood-derived pulp. It is used for various chemical purposes.

Cotton fibers can be largely divided into staple and linter fibers. Staples are mature cotton fibers that exist outside of cotton seeds, and linter fibers can be understood as immature cotton fibers attached to seeds. As a raw material for producing cotton pulp for chemicals, linter fibers, which are immature cotton attached to seeds, are used because they have low crystallinity and excellent reactivity with chemicals.

In order to make these linter fibers into cotton pulp for chemical use, it is necessary to go through a process of removing foreign substances present in the linter fibers. In order to remove foreign substances present in the cotton fibers by a chemical method and to prepare a sheet type or flake type cotton pulp, a process via water is performed. However, since natural cotton fibers have properties such as wax and pectin on the surface of the fibers that do not get wet with water, they must first be removed to impart water-soaking properties. This process is immediately cooked or digested or It is a refining process. Cotton fibers may be immersed in water after the cooking process, but they are still brown and these chromophore materials must be additionally removed to be used for chemical purposes, and this process is a bleaching process. In the bleaching process, chemicals such as hydrogen peroxide may be used.

Hydrogen peroxide, a representative peroxide, is an inorganic industrial chemical useful as an oxidizing agent, and is widely used in fields such as bleaching of fibers and pulp, sterilizing and disinfecting solutions, and organic synthetic reactions. Hydrogen peroxide degrades hydrogen peroxide during transport, storage or use, and its concentration gradually decreases. Hydrogen peroxide is catalytically caused by impurities such as various metal ions or precipitated metal compounds contained in the aqueous hydrogen peroxide solution. Because it decomposes. That is, when hydrogen peroxide reacts with heavy metal ions such as iron (Fe) and manganese (Mn), free radicals are formed, and the formed free radicals are decomposed in contact with hydrogen peroxide again to induce undesirable homogeneous decomposition reactions. , Resulting in the consumption of hydrogen peroxide. Therefore, when heavy metal ions are present in the bleaching process in which hydrogen peroxide is used as a bleaching agent, the decomposition of hydrogen peroxide is promoted and does not exhibit activity, and its function is lost, and the free radicals produced attack the fiber and cause weakness of the bleached fiber It is also done.

Various stabilizers for preventing the decomposition of hydrogen peroxide are generally used. Conventionally, sodium silicate was used as a stabilizer to effectively operate the bleaching action of hydrogen peroxide. Sodium silicate contains sodium (Na) and silicon (Si) as ash components, and among them, silicon (Si). There is a problem in that the ash content of the cotton pulp produced is high because it is not likely to be removed well by this washing and remains in the pulp. In addition, the silicon component has a problem in that clogging occurs by generating scale in various pipes during the process.

Korean Registered Patent No. 1178727 (published August 27, 2018) Korean Patent Publication No. 2004-0022867 (published on March 18, 2004)

An object of the present invention is to provide a manufacturing method using a stabilizer having a reduced ash content as a stabilizer of hydrogen peroxide for bleaching cotton pulp and a cotton pulp produced by such a manufacturing method.

The object of the present invention is a method for producing cotton pulp using cotton fibers, including a bleaching step of bleaching cotton fibers using a bleaching composition containing hydrogen peroxide and an organic hydrogen peroxide stabilizer, wherein the bleaching composition is based on 100 parts by weight of hydrogen peroxide. It is achieved by a method for producing cotton pulp, characterized in that it contains 25 to 50 parts by weight of a stabilizer.

The cotton fibers may include linter fibers.

The organic hydrogen peroxide stabilizer may include sodium salt.

The organic hydrogen peroxide stabilizer may include [ethylenebis[nitrilobis(methylene)]]tetrakisphosphonic acid sodium salt.

The starting component that becomes the ash component in the organic hydrogen peroxide stabilizer may be 0.3% by weight or less.

The organic hydrogen peroxide stabilizer, [ethylenebis[nitrilobis(methylene)]] tetrakisphosphonic acid sodium salt 40 to 50% by weight, distilled water may include 50 to 60% by weight.

The method for producing cotton pulp using the organic-based hydrogen peroxide stabilizer of the present invention can increase the quality of cotton pulp by lowering the ash content, especially the ash content of the cotton pulp, which is made of less silicon component compared to the prior art, and using a manufacturing process or cotton pulp. The piping scale in several processes can be reduced.

As a method for manufacturing cotton pulp, a process for mechanically removing foreign substances from cotton fibers, a cooking process for pulping cotton fibers from which foreign substances have been removed using an alkaline solution, a washing process for washing the obtained pulp, and bleaching the washed pulp A method comprising a bleaching process that is treated with a solution has been used.

The cotton fibers used in the production of the cotton pulp for cellulose derivatives of the present invention are linter fibers. Linter fiber refers to short fibers with a length of 3 to 5 mm remaining on the seeds after extracting long fibers from a cotton seed by a roughening machine. Since linter fiber is short, it cannot be spun and is used as a raw material for the chemical industry. The process of removing foreign matters during the process of manufacturing cotton pulp from linter fibers can be divided into mechanically removing foreign matters and chemically removing foreign matters. At this time, the foreign material includes cotton seeds, sand, dust, and shells of seeds. The process of mechanically removing foreign substances consists of a burned surface and a dry cleaner to remove heavy foreign substances such as seeds and sand and lightweight foreign substances such as dust. The process of chemically removing foreign substances consists of removing wax and pectin on the fiber surface by caustic soda, and then increasing the whiteness by hydrogen peroxide.

In the process of mechanically removing foreign substances, it is preferable to remove the heavy foreign substances such as seeds and sand and lightweight foreign substances such as dust by treating them with a dry cyclone for 5 to 10 minutes at room temperature after burning.

After removing foreign substances mechanically from linter fiber, remove them. The chemical foreign material removal process is to remove wax and pectin on the fiber surface through the cooking process, and the cooking process for this is one or two or more selected from caustic soda, sodium carbonate and sodium silicate having alkalinity as the cooking solution. It may be to use, and when using an alkaline solution of 0.5 to 15 parts by weight based on the pulp weight, it is suitable for increasing the whiteness and reducing the polymerization degree. The cooking solution may further include a refining agent, and it is preferable to use AE440 as a refining agent. The treatment with 50 to 70 minutes at 90 to 110°C using such an alkaline solution can be advantageous in that wax and pectin on the fiber surface can be efficiently removed while minimizing a decrease in polymerization degree. Through this, the fibers become softer, and the wax and pectin components existing on the surface of the cotton fibers can be removed to make them easily immersed in water.

The washing process involves diluting and enriching the cooked fiber. At this time, the dilution is made in a stirrer that can effectively stir the cooked fiber, and dilute the cooked fiber to a fiber concentration of 3 to 4% for effective dilution.

After the dilution is made, it can be concentrated using a screw press or a belt press. Concentrating the diluted fibers to a fiber concentration of 50% or more removes contaminants that have been removed from the fibers in the cooking process, and is then used for efficient bleaching. It is advantageous.

The bleaching process refers to the bleaching step of the present invention in which the pulp washed by the washing process is treated with a bleaching composition to increase the whiteness of the cotton fibers. The bleaching composition of the present invention includes hydrogen peroxide and an organic hydrogen peroxide stabilizer to prevent hydrogen peroxide from being accelerated to decomposition by reacting with heavy metals. The bleaching composition contains 1.5 to 40 parts by weight of an organic hydrogen peroxide stabilizer relative to 100 parts by weight of hydrogen peroxide.

The organic hydrogen peroxide stabilizer of the present invention contains a sodium salt, but does not contain a silicon component that has been a problem in the prior art. The organic hydrogen peroxide stabilizer of the present invention is preferably ethylenebis[nitrilobis(methylene)]]tetrakisphosphonic acid sodium salt (Ethylenebis[nitrilobis(methylene)]tetrakisphosphonic acid Na salt). The components of the organic hydrogen peroxide stabilizer are 0.3 wt% or less as a starting component, and do not contain a silicon component, which minimizes the ash component in the manufactured cotton pulp, which has been a problem in the prior art, and piping during various processes. It is also possible to reduce the scale formation of.

More preferably, the organic hydrogen peroxide stabilizer may include 40 to 50% by weight of [ethylenebis[nitrilobis(methylene)]] tetrakisphosphonic acid sodium salt, and 50 to 60% by weight of distilled water. These organic hydrogen peroxide stabilizers can be used in a smaller amount as a stabilizer compared to conventional sodium silicate, while achieving similar results in viscosity and whiteness obtained from the produced cotton pulp, while reducing the ash content, resulting in higher quality Cotton pulp can be obtained. When the hydrogen peroxide contained in the bleaching composition was 100 parts by weight through repeated experiments, the stabilizer of the present invention preferably contained 25 to 50 parts by weight. If the stabilizer is less than 25 parts by weight, the amount of reaction with the metal ions contained in the pulp is small, which may cause a problem that the bleaching efficiency is lowered. If it is more than 50 parts by weight, the excess stabilizer may cause side reactions, thereby reducing the bleaching efficiency. It can be.

The bleaching composition of the present invention may further include a refining agent and caustic soda (NaOH), thereby enabling more effective bleaching in the bleaching step. The refining agent may be AE440, and functions to prevent decomposition of hydrogen peroxide. Caustic soda is a material that is frequently used as a bleaching agent together with hydrogen peroxide, so that the bleaching step of linter fibers is effectively performed. When the hydrogen peroxide contained in the bleaching composition is 100 parts by weight, the refining agent may contain 0.1 to 1 parts by weight, caustic soda 5 to 15 parts by weight.

[Example]

After mechanically removing foreign substances from the linter fiber, for the cooking process, the linter fiber was prepared according to a liquid ratio of 6:1 to prepare a cooking solution containing a refiner AE440, caustic soda and distilled water, and cooked for 40 minutes at 100℃ in an IR cooking bleacher. To proceed. As the cooking solution, an aqueous solution containing 0.05% by weight of a refining agent (AE440) and 10.6% by weight of NaOH was used.

After washing once with 5L of tap water, remove water by hand and put it in the bleaching composition (liquid ratio 6:1). The bleaching solution is 5.7% by weight of hydrogen peroxide, 2% by weight of stabilizer 1 ([ethylenebis[nitrilobis(methylene)]]tetrakisphosphonic acid sodium and distilled water) as a hydrogen peroxide stabilizer, 0.02% by weight of refining agent (AE440), and caustic An aqueous solution containing 0.42% by weight of soda was used, and the bleaching step was performed at 100°C for 100 minutes through an IR cooking bleacher.

[Comparative example]

In Example 1, 5% by weight of sodium silicate was used as a hydrogen peroxide stabilizer.

For the cotton pulp prepared in Examples and Comparative Examples, viscosity, whiteness and ash content were measured and compared.

Viscosity measuring method

For the viscosity measurement, for each bleached pulp bleached by Examples and Comparative Examples, chopped finely to collect 0.25 g of dry weight and stirred with 25 ceramic beads (diameter 10 mm) for 6 minutes in 25 ml of distilled water. Then, 25 ml of CED (cupriethylenediamine) solution was added and reacted for 1 hour to completely dissolve the pulp. This is calculated by measuring the time when the solution falls from the scale of the capillary viscometer by injecting it into a viscometer (capillary tube type). The viscosity calculation formula is Viscosity(cPs) = Viscometer constant*time(s)*density of pulp(d). Here, the pulp has a viscosity of 1.052.

Whiteness measurement method

To measure the whiteness of the pulp, four or more sheets of 200 g/m ² pulp sheet were prepared and the sample was placed on a whiteness meter light source to measure it.

Method for measuring ash content

In order to measure the amount of minerals contained in the pulp, a method of measuring the mass of the residue remaining after burning the sample is used, and the measurement specimen is placed in a crucible having thermal stability and burned at 525°C for about 4 hours or more. Measure the weight and mark it as content.

Comparison of experimental results of Examples and Comparative Examples Viscosity (cPs) Whiteness (%) Ash content (%) Comparative example 37 86.4 0.6 Example 39 85.1 0.2

Table 1 shows the experimental results for bleached cotton pulp using each hydrogen peroxide stabilizer of Examples and Comparative Examples.

The cotton pulp for cellulose derivatives is slightly different depending on the application, but basically, the viscosity (polymerization degree), whiteness, ash content and content of individual inorganic elements are important quality control items.

In the examples, the viscosity was higher than that of the comparative example, indicating that the polymerization degree was better, and in the whiteness, the examples and the comparative examples showed numerical values in a similar range, but there was no better effect on the whiteness, but the ash content was 0.6% of the comparative example. Compared to the example, it showed 0.2%, showing a result of a significant decrease to less than half, indicating that the quality was improved.

As described above, it was confirmed that the cotton pulp produced through the production method of the present invention has improved whiteness similar to that of the prior art, but has improved polymerization, and can significantly lower the ash content to obtain high quality cotton pulp. Since the components are not included, it is expected that it is possible to significantly reduce the occurrence of piping scale in various processes using a manufacturing apparatus performing the present manufacturing method or cotton pulp produced by the present manufacturing method.

The present invention has been described with reference to one embodiment, but this is merely exemplary, and those skilled in the art will understand that various modifications and other equivalent embodiments are possible therefrom. Therefore, the true protection scope of the present invention should be defined only by the appended claims.

Claims (7)

As a method of manufacturing cotton pulp using cotton fibers,
Bleaching step of bleaching cotton fibers using a bleaching composition containing a hydrogen peroxide and an organic hydrogen peroxide stabilizer,
The bleaching composition is a method for producing cotton pulp, characterized in that it contains 25 to 50 parts by weight of an organic hydrogen peroxide stabilizer relative to 100 parts by weight of hydrogen peroxide. In claim 1,
The cotton fiber manufacturing method of cotton pulp, characterized in that it comprises a linter fiber. In claim 1,
The organic hydrogen peroxide stabilizer is a method of producing cotton pulp, characterized in that it comprises a sodium salt. In claim 3,
The organic hydrogen peroxide stabilizer, [Ethylenebis[nitrilobis(methylene)]]tetrakisphosphonic acid sodium salt production method comprising a sodium salt. In claim 1,
A method for producing cotton pulp, characterized in that the starting component that becomes the ash component in the organic hydrogen peroxide stabilizer is 0.3% by weight or less. In claim 4,
The organic hydrogen peroxide stabilizer, [Ethylenebis[nitrilobis(methylene)]]tetrakisphosphonic acid sodium salt 40 to 50% by weight, distilled water 50 to 60% by weight, characterized in that it comprises a cotton pulp manufacturing method. A cotton pulp produced by the method for manufacturing the cotton pulp of any one of claims 1 to 6.