KR20010001550A - Preparation method for the cornstalk pulping - Google Patents

Abstract

PURPOSE: A process of preparing cornstalk pulp by grinding a cornstalk, high pressure cooking, beating, dispersing, paper making and drying is provided, which inflicts less damage on environment and can substitute wood as raw material of pulp. CONSTITUTION: The cornstalk pulp is prepared by a process of: grinding a cornstalk, high pressure cooking, beating, dispersing, paper making and drying, optionally adding bleaching, wherein the high pressure cooking process comprising one of craft pulping, sulphite pulping, alkaline sulphite pulping and soda pulping is carried out at 120 to 200 deg.C for 1.5 to 4 hr and has a weight mixing ratio of a reactive reagent used in the cooing process to raw material of 3 : 1 to 6 : 1.

Description

Preparation of pulp using corncob {PREPARATION METHOD FOR THE CORNSTALK PULPING}

The present invention relates to a pulp manufacturing technology using herbal plants. Specifically, the present invention relates to a pulp manufacturing technique using corncob.

By using corn cob as the raw material of paper pulp, it is possible to replace the import of wood raw materials, preventing waste of foreign currency, increasing rural income, and producing high quality paper similar to Korean paper.

At present, Korea is the world's seventh largest consumer of paper, producing the world's tenth largest paper producer (5830,000 tons / year paperboard production) or paper with publications, newspapers, printing cardboard, graft paper and bulk paper. The entire amount of pulp is dependent on 100% foreign markets. Because the pulp industry's fostering causes damage to forest resources, it is necessary to develop new pulp materials. To this end, it is necessary to process raw materials of cellulose from various plants to increase the value of use as papermaking. Since Korea is unable to secure pulp raw materials due to depletion of species and forest resources that are not suitable for pulp, research is being conducted to find new turning points.

Conventional paper pulp has been mostly wood pulp, but the recent shortage of wood resources in the world has been a major challenge to produce paper material pulp while protecting forests and maintaining the environment. As a solution to this problem, the production technology of paper pulp is attracting attention from non-wood plant fibers mainly composed of annual or biennial plants. In China, the Middle East, and India, where forest resources are scarce to secure pulp materials, they are using national agricultural wastes or bamboo as raw materials to develop national pulp materials, and even sugar cane tailings that are discarded after sugar production. As a raw material, pulp production processes are being developed.

Generally, non-woody plants tend to be high in pectin, hemicellulose, and minerals and low in lignin. Pulping of non-woody plants is carried out by chemical, semi-chemical and mechanical-chemical methods. Unbleached or bleached pulp can be obtained under very mild conditions compared to wood. Non-wood pulp is characterized by its fiber type, chemical composition, and the type and amount of nonfibrous cells. Therefore, paper made by non-wood pulp alone or by proper mixing with wood pulp is used for various purposes depending on the characteristics of strength, durability, electrical characteristics, gloss, dimensional stability, and printing performance. have.

Non-woody plants include bast, linseed, flax, hemp, cotton, and manila hemp. Korean Patent Publication No. 84-005762 uses bagasse as a raw material for pulp, and Korean Patent Publication No. 91-3216. No. 1 uses dried pine needles collected from fallen leaves, and Korean Patent Laid-Open Nos. 98-9651 and 93-2604 disclose a method for producing pulp using rice straw. In addition, Korean Patent Application No. 85-5895 describes a pulp manufacturing method using tobacco stem.

However, no document has ever been disclosed, and no mention of this invention has been made on the production of pulp using corncob as raw material.

Corn grown in rural areas is used as food or feed, but corn is not used as a feed these days, most of the situation is discarded. There is a need to replace pulp that relies on total imports, to prevent unnecessary waste of foreign currency, to make useful use of agricultural waste, and to increase rural incomes. In addition, there is a need to develop high quality paper such as Hanji. Therefore, cornstalks should be processed in new ways to increase the value of pulping and other materials.

Therefore, this study attempted to produce a new and unusual Korean pulp using corncob and to produce paper with unique properties similar to that of traditional Korean paper. Currently, in most countries, wood pulp is separated from fibrous cellulose to produce paper-melting pulp, and more than 90% of the world's pulp production is wood pulp. Although widely known, Korean papermaking methods can also be used for the production of high quality paper.

Our country has been manufacturing hanji from the bark of bark since ancient times. It is a special product of our country, which is unique because it has unique properties different from Western lipids. Each year between October and November, the mulberry is harvested and placed in a cauldron to boil, peeled off, leaving only the white endothelial inside. The outer shell is simmered in buckwheat lye, smashed with oak bats to soften the vagina, and then the mulberry juice is placed in a paper shaker and floated.

The wood pulp manufacturing industry, which manufactures fibrous cellulose pulp from wood, requires the development of selective reagents that react with lignin but not with cellulose when the reaction reagent is in contact with wood. In addition, the pulp manufacturing process is a large capital equipment-intensive and energy-intensive industry that uses a large amount of water because it is a complex combination of waste liquid recovery and waste treatment processes considering the environment.

The chemical pulp manufacturing process consists of a pulping step that mainly removes lignin from the wood components, and a pulp bleaching and refining step that selectively removes residual impurities in the pulp, and depends significantly on the purpose and quality of the final pulp product. . The pulp used to make conventional fiber or paper is made from pulp material by harvesting conifers, and there are mechanical and chemical methods, and the mechanical method is pulp material-transverse-dermabrasion-milling machine. )-Shipbuilding screen-Qualitative screen-Centrifugal cleaner-Dehydrator-Pulp-Head drum-Wire drum-Press-Undried pearl wool The process for the production of chemical pulp is pulp material-peeling-chipper-cooking pipe- Processes for the production of shipbuilding screen-washing-choice screen-dehydrator-bleaching tower-depilator-pump-set cleaner-headbox-wire-dryer-cutter-packed pulp are used. They all depend on imports of pulp raw materials.

More specifically, the pulp is mainly used in the manufacture of various types of cellulose polymer products by dissolving pulp for paper and high-purity cellulose produced from wood as acidic polymers through chemical reactions. There is a dissolving pulp used to prepare cellulose derivatives as high as 98%. The process of separating fibrous cellulose from wood is a method of producing chemical-mechanical pulp that removes phenolic lignin, which is strongly chemically bound between cells in wood, or mechanically forcibly separates it by physicochemically softening lignin. .

Delignination of wood was produced by kraft process of nucleophilic reactors -OH, -SH, S2- etc. present in alkaline cooking solution attacking lignin polymer composed of phenylpropane units to generate new phenolic hydroxyl groups. Quinone methide reacts with nucleophilic reagents to cause sulfidation reactions, and is soluble in alkali with low molecular weight. In the acid sulfite method, bisulfite ions are bonded to carbonium ions formed by hydrolysis of phenolic ether bonds to be converted into lignosulfate to be water-soluble. However, among the wood composed of various polymer materials, the reaction solution is reacted with a cooking reagent that selectively reacts only with the lignin polymer, and the reaction solution is strong alkali or acid. Due to the high temperature of about 150-170 ° C., which is applied to obtain an economical delignin rate, some of the cellulose is decomposed, so that only cellulose on the fiber cannot be separated purely. Therefore, paper pulp should be bleached to high whiteness through more than 5 stages of oxidation and alkali extraction in order to remove residual lignin in consideration of pulp yield and economical efficiency.

In order to provide a pulp of replacing the wood pulp to provide a good pulp to replace the conventional wood pulp by providing a foreign currency prevention, high-quality pulp. An object of the present invention is to provide a method of adding bleaching to the pulp manufacturing process.

In another aspect, the present invention provides a method for producing a pulp other than wood pulp, recycled pulp, or corn in the method for producing pulp using a corncob.

The present invention relates to a method for producing pulp from a herbaceous raw material, and more particularly, to a method for producing pulp using a corncob.

Corn, which is a raw material of pulp used in the present invention, is a flowering plant and a year-old stem, which stands straight and has a height of 1.5-2.5m, and generally does not branch. The leaves are 5-10cm long and more than 1m long. Maize is divided into eight species of machi, maize, sweet, kapok, allele, soft persimmon, and vulgar edema, depending on the shape and nature of the seed. Corn fruits are used for food, and stems and leaves are used for livestock feed and are used as ensilage. It is also used for construction, fuels, fillings, cushions, sandals, and pharmaceutical raw materials.

Wood, which is the main raw material of pulp, is a tree grown by cells accumulated through cell division. Wood is densely or alternately placed in a lignin matrix in which fibrous cellulose microfibers are a cement-like structure, and some are chemically bonded to each other to increase the strength of wood. It was promoted by Feudenberg and analyzed decomposition products through hydrolysis, pyrolysis, substitution reaction, substitution reaction, oxidation reaction, reduction reaction, etc. As a result, it was composed as shown in FIG. 2 and found to be different according to conifers and deciduous trees. Turned out to be different. Wood, which is used for industrial purposes due to its high density among plants, is a coniferous tree, which depends on the structure and species of the monomers that make up the lignin content in the cell wall.

Compared with the content of each component of the corn pulp corn pulp of the present invention has the highest hemicellulose content and low lignin content, whereas wood pulp has the highest cellulose content and very high lignin content. The composition of the wood pulp is 45% cellulose, 27% hemicellulose, 28% lignin and 3% extract (including others). Corn length is 1-4 mm, width is 20-40 μm, and thickness is 5-10 μm.

The present invention is to provide a method for producing pulp consisting of the step of crushing, high pressure cooking, beating, dispersing, papermaking and drying cornstalk. The manufacturing method of corncob is similar to that of wood, but considering the lignin content, the reaction conditions are milder than wood pulp, which makes it easier to pulp, and the treatment time is slightly longer than other herbs.

In addition to this, the step of bleaching the pulp may be added. Pulp bleaching generally uses oxidants and chlorine to remove residual lignin only in the first step. The chlorination step aids in lignin and is hydrophobized by reaction with unsaturated fatty acids, resinous acids, and uncompensated compounds. Therefore, chlorination is followed by thermal alkali extraction, which also alkalines saponification of fatty acids, waxes, and other ester components to liberate fats in the form of soap, dissolving the uncompensated lysate and dissolving the degraded lignin fragments. The most effective surfactant in the alkali extraction step is nonylphenol with polyethylene glycol branches. However, the whiteness of the pulp improves the whiteness of the pulp by connecting bleaching of chlorine acid, chlorine dioxide or bleaching hydrogen peroxide like the bleaching of paper pulp. Therefore, the bleaching of the dissolved pulp is bleached under the same conditions as the paper pulp bleaching.

When preparing pulp using corncob, pure corn pulp may be prepared. However, in order to change various physical properties, pulp may be prepared by adding wood pulp, herbal pulp other than corn, or recycled pulp in the dispersing step. have.

In addition, in order to improve the physical properties of the pulp made of only other corn or in addition of other pulp, the pulp may be prepared by adding a water-soluble polymer raw material. Preferably, there are polyvinyl alcohol or polyacrylamide, and the reason for adding such a water-soluble polymer is to improve surface conditions, increase strength, expand applications, and prevent moisture.

In addition, starch, strength enhancers, fiber expanders, optical brighteners or polymer electrolytes may be added in the preparation of the pulp. Preferred examples of the polymer electrolyte include polyamines, polyethyleneimines, and polyethylene oxides, which serve to prevent entanglement of fibers and to disperse each other. Other additives lower the manufacturing cost of paper, densify tissue, create fiber expansion, print adequacy, paper opacity, etc.Aluminum sulfate, calcium carbonate, clay, aluminum hydroxide, diatomaceous earth, liquor, Talc, carboxymethylcellulose, diethylamine chlorochloride, gum rosin, wood rosin and the like can be added.

Since the paper is not floated by the normal pressure method in the pulp manufacturing process, the pressure pulping method such as kraft pulping, sulfite pulping, alkaline sulfite pulping or soda pulping is preferable. Atmospheric pressure pulping method is the result of not being fully cooked keratin and internal fiber of corncob, and also a considerable loss of cooking chemicals during the experiment.

The reaction conditions of the high pressure cooking process are almost the same in the above four pressure cooking methods and there is the biggest difference in the reagents used. Alkaline sulfite pulping and soda pulping are used, and their reaction conditions are large or similar, but there are differences in the reagents used. The craft pulping method uses an aqueous solution composed of NaOH and Na 2 O, the sulfite pulping method uses an aqueous solution composed of Na 2 SO 3 and Na 2 CO 3, and the alkaline sulfide method uses an aqueous solution composed of NaOH, Na 2 CO 3, Na 2 SO 3, Na 2 SO 3, and AQ. And, soda pulping method is to pulping using an aqueous solution of NaOH only.

The reaction time of the high pressure cooking process is preferably 1.5 to 4 hours, the reaction temperature is 120-200 ℃, the liquid ratio of the aqueous solution of the reactive reagent used in the cooking process and the pulp material (wt / wt) of 6: 1 to 3 : 1 is preferred. When the liquid solution of the reactive reagent and the pulp material is large, the chemical treatment is so strong that all weak cellulose melts, and only strong fibers remain to increase the strength of the paper.

The corn is collected and the meat is removed, then the fiber is crushed through the grinding process to remove the dead skin and other impurities, and then dispersed through the beating process. An experiment for preparing pulp was performed. The physical properties of the paper made were measured.

As a result of comparing the properties of pulp prepared by various methods, specific volumetric measurements of pure soda pulp, kraft pulping and alkaline-sulfite pulping showed the highest value in soda pulp. The fibrous structure was very soft and resolved into bulky tissue. Tensile strength measurement shows the highest value in kraft pulp, and it can be seen that kraft pulp is best cooked and composed mostly of fibrous structure. Kraft pulp showed the highest value in rupture strength and abrasion resistance measurements, while alkaline-sulfite pulp was the largest in tear strength.

Item Bleached soda pulp Bleached Kraft Pulp Bleached Alkaline-Sulfite Pulp Bleached Softwood Kraft Pulp (NBKP) Specific volume (㎥ / g) 2.15 1.87 1.92 2.12 Tensile Strength (N㎡ / g) 17.52 28.82 23.12 39.40 Bursting Strength (N㎡ / g) 0.08 0.15 0.12 0.41 Internal theft (the frequency) 1.33 2 1.67 4.36 Tear strength (N㎡ / g) 0.43 0.41 0.46 2.59

About 60 wt% of bleached coniferous kraft pulp, the physical properties of paper samples made by mixing 40 wt% of soda pulp, kraft pulp, and alkaline-sulfite pulp made with corn cob were much better than those of pure corn cob pulp. Specific volume measurements were nearly equally improved by about two times in almost three types of pulp: soda pulp, kraft pulp and alkaline-sulfite pulp. In particular, the measured values of theft resistance increased more than 70 times and the tear strength increased more than 5 times. This phenomenon shows the characteristics, economics and infinite development of pulp made from corn.

Experimental Values of Paper Sheets Made from Bleached Coniferous Kraft Pulp (NBKP, 60wt%) and Bleached Corn Stalk Pulp (40wt%) Item Bleached soda pulp Bleached Kraft Pulp Bleached Alkaline-Sulfite Pulp Bleached Softwood Kraft Pulp (NBKP) NBKP corn NBKP corn NBKP corn NBKP corn Fiber composition (wt%) 60 40 60 40 60 40 60 40 Specific volume (㎥ / g) 1.98 1.89 1.98 2.12 Tensile Strength (N㎡ / g) 32.58 36.27 34.42 39.40 Bursting Strength (N㎡ / g) 0.27 0.27 0.29 0.41 Internal theft (the frequency) 77 85 78 4.36 Tear strength (N㎡ / g) 1.69 2.08 1.52 2.59

The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not intended to be limited to the following examples.

Example

Reagents and Materials

NaOH, Na ₂ SO ₃ , Na ₂ S, Na ₂ CO ₃ and the like were used as cooking reagents, and sodium hypochlorite (NaClO) and chlorcalk (Ca (ClO) ₂ ) were used as reagents for bleaching.

The raw materials for pulp used are harvested cornstalks grown in farmhouses, completely dried in the shade and cut into 3-4 cm to remove fallen leaves and other inadequate parts on the skin, and then split to remove endothelial, ie meat And a certain size of material made through a grinder was used.

The apparatus used for the manufacture of pulp used a 3-liter beaker, a heating plate, a magnetic stirrer, and a water bath apparatus when processed at room temperature, and was used while shaking a 10 Kg / cm2 heating pressure vessel under pressurized conditions. Automatic shaker shaker was used for washing and neutralization, and special equipment as shown in Figure 5 was used for the liquid grinding of pulp material. For the pulp blasting, a PFI-mill (heating condition: 1.8Kg / c㎡, Clearance 0.3mm) was used, and a special standard sheeting machine (Hand Sheet Machine, TMI, 173 mm in diameter) was used to produce the pulp sheet. Used. At this time, the radius of the sump container has a specification of 17.3 cm and the hole size of the sieve is 0.38-0.39 mm.

In order to form the produced paper sample, a thick nonwoven fabric and a milling roller used for the prevention of dry cotton wrinkles, and a binary body type apparatus were used. In order to measure the characteristics of the made pulp, specific volume, tensile strength tester (Schopper type, Toyo seik), tear strength tester (Mullen tester, BF Perkin), MIT foldering endurance tester, Timus Olsen testing machine ), Tear strength tester (Elmendorf Tearing Tester, Thwing Alert Insturment).

Comparative Example 1

In the atmospheric test, 100 g of corncob samples (denitration) were prepared at concentrations of 10% and 15% using NaOH, Na ₂ SO ₃ , and reagents for 2 hours, 3 hours, and 4 hours. It was. The cooked sample was filtered through a 100 mesh sieve, and the remaining one was taken, neutralized by dipping in water for 1 day, and then dried at 80 ° C. for 5 hours to use as a raw material of pulp. The yield of the sample from this experiment is as follows. Yields of 2 hours, 3 hours, and 4 hours at 150 ° C. with 15% NaOH were 65.4 g, 63.2 g and 62.3 g, respectively, and 15% Na ₂ SO _{3 at} 150 ° C. for 2 hours, 3 hours, and 4 hours. The yields obtained at the time of treatment were 68.34 g, 65.12 g and 62.7 g, respectively, and the yield was about 65%. The cooked sample was filtered through a 100-mesh sieve, and the remaining one was taken, immersed in water for about 1 day, then beaten, and then used as a raw material for pulp, but paper did not float.

The calculation of the pulping yield was performed by cooking and washing with each pulping condition, spinning 3,000 times with a fiber dissociator, and drying the resultant for 5 hours at 80 ° C. in a hot air dryer, and then yielding the yield in the following equation.

Example 1

In the present invention, the cooking unit used for the pressure cooking method was put into a rotary laboratory cooking unit (Pressure 0-10Kg / cm3, Temp. 0-200 ° C, Capacity 40ℓ) of an electric heating method using a pressurizing device, and the highest cooking. The soda pulping method was carried out with a cooking time of 1.5 to 4 hours with a variable ratio of 4: 1 to 6: 1 (aqueous solution: sample dry weight wt / wt) at a temperature of 150 ° C.

Soda pulping test conditions, that is, 500g of the sample was first put in a rotary experimental cooking section (Pressure 0-10Kg / cm 3, Temp. 0-200 ° C, Capacity 40ℓ), and at a maximum cooking temperature of 150 ° C. The result of experiments over 1.5 hours after fixing with a liquid ratio of 4: 1 (aqueous solution: dry weight wt / wt) using only% NaOH showed that the node of corncob was not cooked and remained intact. It was an inhibitor. However, secondly, 500 g of the sample was placed in a rotary experimental cooking section (pressure 0-10 Kg / cm 3, Temp. 0-200 ° C., Capacity 40 L) and composed of 20% NaOH at a maximum cooking temperature of 150 ° C. The solution was fixed at a ratio of 6: 1 (aqueous solution: dry weight wt / wt sample) and tested over 3 hours to obtain a sufficient pulp, yielding 21-35 wt%.

Example 2

The cooking liquor used primarily was fixed with a liquid ratio 4: 1 (aqueous solution: dry weight wt / wt) composed of 14% Na2SO3 and 4% Na2CO3, and was tested at 150 ° C. for 2 hours. Secondly, the cooking liquor was fixed with a liquid ratio 6: 1 (aqueous solution: wt / wt of the sample dry weight wt / wt) composed of 28% Na2SO3 and 8% Na2CO3, and the result was experimented for 4 hours at 150 ° C. The pulp yield obtained from the experiment was about 26-41 wt%.

Example 3

Example 1 except that the cooking reaction solution was fixed at 10: NaOH, 20% Na2SO3, 4% Na2CO3, and 0.1% anthraquinone with a liquid ratio of 6: 1 (aqueous solution: dry weight wt / wt). It was done in the same way. The pulp yield obtained was about 23-38 wt%.

Example 4

Craft pulping method was carried out except that 500 g of the sample and the cooking reaction solution were fixed at a liquid ratio of 6: 1 (aqueous solution: dry weight wt / wt) consisting of 20% NaOH and 15% Na2S, and the experiment was conducted for 1.5 hours. It carried out in the same manner as in Example 1. The yield of the pulp obtained was 25-32 wt%.

Example 5 Preparation of Seaweed and Sheet Paper

That was pulped with the dried sample at a 10% wt / wt concentration with water by taking 30g fully immersed for more than 2 hours by the method of TAPPI Standard T 248 Pm-beating unit 74 - PFI mill (beating conditions: linear pressure 1.8Kg / cm ^2, Clearance of 0.3 mm) was performed by the kraft system 500 times and the alkali sulfide system 1100 times when 40 ° C SR was used as a standard before and after.

Example 6 Pulp Bleaching Process

Reagents used for bleaching were sodium hypochlorite (NaCIO), chlorcalc (Ca (CIO) 2), and the like, and sodium hydroxide or sodium silicate was used to adjust the pH 9-PH 11. Pulp concentration and experimental temperature were performed at 40 ° C in the concentration range of 4% to 6% and at 35 ° C in the range of 10% to 16%.

In order to extract the remaining alkali after bleaching the pulp of corn, the pulp concentration was 10%-20% and extracted for 1 to 2 hours in the range of 45 ℃-80 ℃.

Each paper sheet was prepared using a special sheet standard machine (Hand Sheet Machine, TMI, 173 mm in diameter) to float the sheet of pulp prepared in the above example.

Example 7

The physical properties of the soda pulp, kraft pulp, alkaline-sulfite pulp, and sulfite pulp prepared through the above experiments were measured. In order to improve their properties and develop various applications of corn cob pulp, each pulp was mixed with about 60% of bleached coniferous kraft pulp by 40%, and the specific volumetric tensile strength, tear strength, tear strength and tear strength were measured and compared. It was. The results are shown in Table 1 and Table 2.

The present invention provides a method for producing pulp using cornstalk, specifically, a method for producing pulp consisting of crushing, autoclaving, beating, dispersing, papermaking, and drying corncobs, thereby reacting under mild conditions. It is less harmful and can replace wood, which is a raw material of pulp, which protects forests, prevents waste of foreign currency caused by imports of wood, and raises farm household income and obtains high quality pulp similar to Korean paper. There is an advantage.

Claims (7)

A process for producing pulp comprising the steps of crushing, autoclaving, beating, dispersing, papermaking and drying corncobs. The method of claim 1, further comprising bleaching the pulp. The method according to claim 1, wherein the high pressure cooking step of the pulp manufacturing process is kraft pulping, sulfite pulping, alkaline sulfite pulping or soda pulping. According to claim 3, wherein the reaction time of the high-pressure cooking process is 1.5 to 4 hours, the reaction temperature is 120-200 ℃, the liquid ratio of the aqueous solution of the reactive reagent used in the cooking process and the material (wt / wt) of 3: 1 To 6: 1. The method of claim 1, wherein wood pulp, herbal pulp other than corn, or recycled pulp is added at 20-80% by weight of the total pulp to prepare the pulp. The method of claim 1, wherein a pulp is prepared by adding a water-soluble polymer raw material such as polyvinyl alcohol or polyacrylamide. The method of claim 1, further comprising starch, strength enhancer, fiber expander, fluorescent brightener, or polymer electrolyte.