Method of preparing pulp from corn stems

FIELD: paper-and-pulp industry.

SUBSTANCE: corn stems are reduced to fragment, boiled, ground, dispersed, flattened, and dried to produce paper sheets. Boiling is carried out for 1.5-4 h at ratio of aqueous solution of reagent to corn stem material between 3:1 and 6:1 and temperature 120-200°C.

EFFECT: achieved high quality of pulp, improved environmental condition, and reduced expenses.

5 cl, 2 tbl, 7 ex

 

Background of the invention

The present invention relates to a process for the production of pulp using herbaceous plants, more specifically to a method of manufacturing pulp from cornstalks.

Using corn stalks as raw material for paper pulp is used to replace the import of raw wood, to save foreign currency, increase income from agriculture and to ensure the production of paper of high quality.

At the present time, given the growing national income, Korea is the tenth country in the world in industrial production (production of paper and cardboard is 5830000 tons per year), as well as the seventh country-consumer paper used for publications, Newspapers, cardboard for printing, Kraft paper and plump soft paper. However, total production of pulp for making paper completely (100%) depends on foreign supplies. Since the development of the industry pulp leads to the reduction of forest resources requires the development of new materials for paper production. This will have to produce and process cellulose materials from different plant species and improve their customer value. The species of trees growing in Korea, not suitable for production is DSTV pulp, the harvesting of timber in this country for the production of pulp insufficient and therefore it is impossible to provide the required amount of raw materials for the production of paper pulp. In this regard, often there are reports on research to find new ways for industry pulp.

Typically cellulose pulp for making paper, mainly obtained from wood. However, because lately all over the world is compounded by the shortage of wood resources, there was a serious problem of ensuring the production of pulp and paper without deforestation and environmental destruction. Program for the solution of this problem can be noted efforts been made to develop technologies for the production of pulp from non-wood plant fibers using quality basic materials one - or two-year plants. To obtain raw material for pulp production in China, the Middle East and in India, that is, in the deficit countries forest resources expended considerable effort on the development of cellulosic materials using herbaceous plants, such as bamboo and agricultural waste, as well as on the development of technological processes of production of pulp from waste stems saharn the th reed, usually slaughtered after running out of sugar.

Generally speaking, non-wood plants contain a lot of pectin, a type of hemicellulose and inorganic substances, as well as a bit of lignin. For the production of pulp mass from non-wood plants use chemical Poluchenie or mechanical ways to get unbleached or bleached in a very mild conditions compared to wood materials. Non-wood pulp mass is characterized by the appropriate form of fibers, chemical composition, and the type and number of cells fibrous materials. Therefore, the paper made from non-wood pulp or in appropriate combination with a wood lot, finds wider applications in accordance with the strength, durability, electrical characteristics, gloss, dimensional stability and printability, and the quantity of such use cases is constantly increasing.

Examples of non-wood plant materials are: the inner layer of the bark of the paper mulberry tree, flax, hemp crop, cotton and Manila hemp, etc. In the art have already been attempts to develop methods of producing pulp using quality raw materials such as GM is x sugar beet (as described in laid Korean patent No. 84-005762), dry pine needles collected from fallen needles (see lined Korean patent No. 91-3216), or rice stalks (see lined Korean patent No. 98-9651 and 93-2604). In addition, in the application for Korean patent No. 85-5895 considered a method of obtaining pulp from the stems of tobacco.

According to this author, the invention is a method of obtaining pulp from cornstalks not described in any document published prior to the filing date of this application.

Varieties of maize cultivated in rural areas, used as food for humans or as fodder for cattle. A large part of the corn stalks are used in crushed form to fertilize the soil, although some of them used to feed cattle. There is a serious need for alternative raw material for making pulp to minimize unnecessary costs foreign exchange, and to find a good use agricultural waste to increase income from agriculture. There is also a need to develop high-quality paper. Therefore, it is necessary in a new way to handle the corn stalks and increase their use in the manufacture of cellulosic materials or other materials of the same purpose.

Therefore, the present invention attempts to obtain the new pulp from cornstalks and making paper with high quality and unique characteristics. Because currently, in most countries, the production of paper and dissolving pulp produced by separating fibrous cellulose from wood sources, more than 90% of the world production of pulp is wood pulp mass.

In Korea a long time developed the Korean paper from the bark of the paper mulberry, receiving purely Korean product with specific characteristics, which differs from Western paper on physical properties. For example, Korean paper has much better durability, insulation and breathability.

Usually for the development of the Korean paper every year in October and November collect the bark of the paper mulberry, boiled in cauldrons and removed from the top layer, leaving only the white pieces. The outer layers of the cortex of long-boiled buckwheat liquor, and then beat it with a mallet to soften. Then the resulting broth paper mulberry add in debarking Chan to generate a sheet of paper.

In the production process of the fibrous pulp based on wood you want to use selective reagent composition that reacts when exposed to wood material for cellulose and lignin. Because the process of obtaining a whole is ulaznoj mass, from the point of view of environmental protection, is a set of processes for wastewater treatment and waste treatment, production of wood pulp is considered to be capital-intensive and energy-intensive industry with the use of large equipment and the consumption of vast quantities of water.

Obtaining pulp chemical method includes the step of conversion of cellulose pulp for the removal of lignin from wood composition ingredients, as well as the stage of the bleaching and cleaning of pulp for selective removal of residual impurities contained in the pulp. Specific chemical method of obtaining pulp can vary considerably depending on the subsequent use and desired quality of the finished product pulp. Usually the pulp mass is used to produce paper from wood of coniferous and deciduous species. Such raw material is processed into wood pulp mass mechanical, chemical or polychemicals way. The mechanical process of obtaining pulp consists of okurivanija, cross cutting, grinding, roughing screening, fine screening, treatment in the centrifuge, water separation, bleaching, washing, drying and packaging. While the chemical process of obtaining cellulosebased consists of okurivanija, crushing, cooking, draft screening, fine screening, washing, cleaning the centrifuge, water separation, bleaching, drying and packaging.

In particular, there are two types of pulp - the pulp for making paper and soluble cellulose mass. Soluble cellulose mass is obtained by pre-processing and chemical pulping to produce high-purity cellulose product and used for manufacture of various cellulosic polymer products and obtain cellulose derivatives having a high content of alpha-cellulose, comprising 90-98%. Poluchilisi way pulping is moderate chemical treatment followed by mechanical separation of fibres pulp.

Sulfate method of removing lignin from wood involves the use of alkaline pulping solution containing nucleophilic groups such as-OH, -SH and-S2that affect polymer lignin, educated elementary phenylpropane units, obtaining PANalytical groups, forming cinematic, which reacts with the nucleophilic reagent, activating the reaction of sulfate crystallization and thereby destroying the polymer lignin, soluble in alkaline solution. When the acid sulfite method provides for the hydrolysis of simple relations ether f the Nola ions N +getting connection bisulfite ions, resulting in a polymer lignin is converted into water-soluble lignosulfate. However, since implementing these methods use the cooking reagent that selectively responds to the polymer lignin, and not the other polymeric ingredients wood, cooking solution is a solution of a strong alkali or acid. In addition, in these methods, it is impossible to select varieties of high-purity fibrous cellulose, since some varieties of cellulose decomposes at high temperature to be maintained in the range of about 150-170°to achieve cost-effective rate of release of lignin. Therefore cellulose pulp for making paper must undergo bleaching to obtain a high brightness level using the method of selective removal of residual lignin by oxidation, at least in five stages and/or by using recovery and extraction with alkali, from considerations of pulp output and economic aspect.

Brief description of the invention

The present invention is directed to a method of obtaining pulp of good quality from the stalks of corn, by which the corn stalks can be used for the production of high quality CE is lulose mass instead of the usual wood pulp. The method of obtaining further includes the step of bleaching pulp.

The present invention also is to develop a method of producing pulp from cornstalks, you can add other types of pulp, such as wood pulp mass, pulp and the pulp from waste paper or pulp and a lot of other herbaceous plants.

Detailed description of the invention

The present invention is directed to a method of obtaining pulp using herbaceous plants and, in particular, to a method of obtaining pulp from cornstalks.

As raw material in the present invention are eight varieties of corn: dent corn, hard corn, sugar corn, popcorn, powdery corn, starchy sugar corn, corn waxy and soft corn, depending on the shape and properties of the grain. The fruits of the corn used in food and silage from cut stems and leaves used as fodder for animals. In addition, different varieties of corn used as a material for construction, fuel filler, bedding, braided sandals, medical supplies, etc.

Traditionally the main source of pulp is a wood which is formed in the form of CTE is OK cells growing trees. In the wood contains microfiber, densely arranged in alternating order in a matrix of lignin, which structure is similar to cement, and partially related to each other by chemical bonds that strengthen the wood. In the publication authors Feigenberg (Feudenberg) and others analyzed the products of decomposition by hydrolysis, pyrolysis, substitution, oxidation and reduction, and it was determined that the wood has a different structure depending on the source type, i.e. conifer, deciduous tree or herbaceous plant. Coniferous wood is used as an industrial material, and is using it based on the structure of elementary units of the lignin contained in the cell walls of wood.

With regard to the composition, corn stalks, in accordance with the present invention, contain more hemicellulose and much lower amounts of lignin, while the wood contains a large amount of pulp and a large number of lignin. For example, the wood contains 45 wt.% cellulose, 27 wt.% hemicelluloses, 28 wt.% lignin and 3 wt.% other extracts. Corn stalk has elementary fiber length of 1-4 mm, a width of 20-40 μm and a thickness of 5-10 μm.

The present invention is directed to a method of obtaining pulp from cornstalks, comprising the steps is melcene, cooking, refining paper pulp molding paper and drying. This method of receiving pulp from cornstalks in many respects similar to the method for producing pulp from wood, but requires less stringent conditions for obtaining pulp in connection with low lignin content, etc. But receiving pulp from cornstalks takes quite a long time compared with the production of pulp from other herbaceous plants.

The method of obtaining pulp from cornstalks may additionally include a step of bleaching pulp for bleaching pulp usually use oxidizing or reducing agent. The method may further include the step of chlorination using chlorine only at the first stage of the process for removal of residual lignin. Stage chlorination makes lignin hydrophilic by reaction with an unsaturated aliphatic compound, drugs fluoro or resinator. After chlorination carry out the step of thermal alkaline extraction, which provides for alkaline saponification of fatty acids, waxes and other esters from free fatty acids to form soap. Fatty acid dissolves drugs fluoro and decompose the lignin fragments. One of the most eff is active surfactants, used in the alkaline extraction stage is Nonylphenol having a branched polyethylene glycol chain. As wood pulp weight, pulp weight of the corn stalks are subjected to bleaching with hypochlorite, chlorine dioxide bleaching or whitening hydrogen peroxide to improve the whiteness of the product.

To improve and/or provide desired properties to the cellulose pulp from cornstalks can be added to the pulp from wood, herbaceous plants or from waste paper.

Alternatively, you can enter a water-soluble polymeric material in the pulp mass, consisting only of corn stalks or optionally containing another pulp mass, with the aim of improving properties of pulp. In a preferred variant of embodiment as a water-soluble polymer may be used polyvinyl alcohol or polyacrylamide. water-soluble polymer is introduced into the pulp mass to improve the surface condition and strength of paper, extensions of the applications and ensure its water resistance.

In the process of obtaining pulp, you can enter additional ingredients, such as starch, agent for hardening the paper, the agent for enhancing fibers, fluorescent bleach or polymer electrolyte. Preferred instances the polymer electrolyte may include polyamine, polyethylenimine, polyethylene oxide, etc. Polymer electrolyte prevents entanglement of the fibers and disperses the pulp mass. Other additives make the structure of the pulp dense and provide extension of the fibers, printability and opacity of paper, and reduce production costs. Examples of other additives include aluminum sulfate, calcium carbonate, kaolin, aluminum hydroxide, infusorial land, lipid, glucose, talc, carboxymethylcellulose, diethylaminoethylamine, gum rosin, rosin extraction, etc.

Among the stages of obtaining pulp boiling under high pressure, preferably you can use the methods of cooking pulp under pressure, such as sulphate cooking, sulphite cooking, alkaline sulfite cooking and cooking soda, because the paper is not produced using the method of cooking at atmospheric pressure. The method of cooking at atmospheric pressure does not provide a satisfactory provarivanija keratin layer and the inner fiber of corn stalks, and, therefore, leads to a significant loss of the cooking reagent.

Reaction conditions boiling under high pressure are almost the same as in the implementation of the above four ways of cooking, except for the type of reagent. For example, the way Mel who offered sulfite cooking and the way alkaline cooking is carried out in the same conditions, but using a different reagent. In the process of sulphate cooking using an aqueous solution of NaOH and Na2S, in the process sulfite pulping is used an aqueous solution of Na2SO3and Na2CO3when the process of alkaline sulfite pulping is used an aqueous solution of NaOH, PA2CO3and AQ (anthraquinone), the implementation of the alkaline cooking method is used only aqueous NaOH solution.

Stage cooking at high pressure is usually conducted in the following conditions: reaction time is 1.5-4 hours; the reaction temperature is 120-200°C; ratio (weight to weight) aqueous solution of the reagent and raw material for pulp chosen in the range from 3:1 to 6:1. If the ratio (weight to weight) aqueous solution of the reagent and raw material for pulp exceeds the above range, the use of the above chemicals leads to the dissolution of all loose cellulose, so that they remain durable fibers to increase the strength of paper. Thus, the ratio of the aqueous solution of the reagent and raw material for pulp should be adjusted to achieve an adequate level to meet the economic requirements.

The collected stems are separated from the fleshy texture, is subjected to grinding and is atrivo to ensure melting of the fibers and, after removal of the keratin layer and other impurities, is subjected to the grinding and tearing. Then make a sheet of paper by forming sheets of paper from the dispersed pulp using listonline machine, which then gives the desired size and dried.

For each of the obtained paper varieties, obtained by cooking soda, sulphate cooking or alkaline sulfite cooking, measure physical properties.

The highest specific volume is obtained from pulp obtained by alkaline cooking only from the stalks of corn, which indicates that the fibrous structure of the cellulose pulp prepared using alkaline cooking, it turns out very soft and forming a three-dimensional structure. Test tensile strength showed that the pulp obtained in the sulfate pulping, showed the highest tensile strength and is best cooked. These results demonstrate that cellulose sulfate pulping consists mainly of fibrous tissue. Cellulose sulfate cooking has the greatest resistance to bursting and resistance to fracture, while cellulose alkaline sulfite pulping has the greatest tensile strength.

Table 1/td>
OptionsBleached soda pulpBleached Kraft pulpBleached alkali sulfite celluloseBleached Kraft pulp from coniferous breeds
Specific volume (m3/g)2,151,871,922,12
The stretch factor (Nm2/g)17,5228,8223,1239,40
The rate of rupture (kPa m2/g)0,080,150,120,41
The resistance to fracture (the number of double folds)1,3321,674,36
The rate of rupture (mn m2/g)0,430,410,462,59

All sheets of paper obtained by mixing 40 wt.% soda pulp from cornstalks, sulfate pulp from cornstalks or alkaline sulphite pulp from cornstalks from about 60 wt.% bleached Kraft pulp from softwood (BSSAP)had significantly better physical properties compared to the pulp mass, derived from the same corn stalks. Three types of cellulose, i.e. sodium cellulose sulfate is the second cellulose and alkaline sulfite cellulose, mixed with BSSAP showed almost twice as much specific volume and resistance to bursting, at least, almost seventy times greater resistance to fracture and at least five times greater tear resistance than cellulose, obtained from some of the corn stalks. This confirms the acceptability characteristics, economic benefits and projected long-term development in the field of production of pulp from cornstalks.

Table 2

The properties of the sheets of paper containing BSSAP (60 wt.%) and bleached pulp from cornstalks (40 wt.%)
OptionsBleached soda pulpBleached Kraft pulpBleached alkali sulfite celluloseBleached Kraft pulp from coniferous breeds
AndInAndInAndInAndIn
Fiber content (wt.%)6040604060406040
Specific volume (m3/g)1,98 1,891,982,12
The stretch factor (Nm2/g)32,5836,2734,4239,40
The rate of rupture (kPa m2/g)0,270,270,290,41
The resistance to fracture (the number of double folds)7785784,36
The rate of rupture (mn m2/g)1,692,081,522,59
Note. And: BSSAP IN: pulp from cornstalks

The best way of carrying out the invention

Next, you will see a more detailed description of the present invention with reference to the following examples, which are illustrative and in no way are intended to limit the present invention.

Reagents and materials

As a cooking agent in the present invention used NaOH, PA2SO3, Na2S and Na2CO3and as the bleaching agents used sodium hypochlorite (NaClO) and calcium hypochlorite (CA(lO) 2).

As raw material for pulp used the stalks of corn grown on the farm and completely dried in the shade. Dried corn stalks cut into pieces with a length of 3-4 cm, cleaned of leaves and other unwanted parts of the outer layer was separated to remove the inner skin, i.e. fleshy texture, then grind to a desired size by passing through a shredder and grater.

To obtain pulp used a three-liter vessel, heating the tiles, magnetic stirrer and double steam boiler, which was used in atmospheric conditions as well as heated tank under pressure of 10 kg/cm2with agitation at an elevated pressure. For flushing and neutralizing used automatic apparatus for stirring and for grinding liquid pulp used a special device. For grinding pulp used the machine for grinding type PFI (grinding conditions: a pressure of 1.8 kg/cm2the gap 0.3 mm), and for molding pulp sheets used special standard lithoscarabaeinae apparatus (hand sheet machine manufacturing company TMI Inc., 173 mm in diameter). In this case, the radius of the fill tank was 17.3 mm, and the size of the hole sieve amounted to 0.38 to 0.39 mm

To shape the prepared sample is then prevent sagging on the dry surface of the paper sample used thick non-woven fabric, eject rollers and paper mechanism dual cylinder. Characteristics of the pulp was measured using special volumetry and device for measuring the tensile strength (unit Shopper (Schopper), manufactured by Toyo seik Inc.), device for measuring the resistance to punching shear (test and measurement instrument of the type Mullen production company B.F.Perkin Inc.), measuring device for determining the resistance to fracture (production company Timus Olsen testing machine Inc.) and device for measuring the resistance of the gap measuring device Elmendorf (Elmendorf) to determine the resistance to rupture of the company's production Twing Alert Instrument Inc.).

Comparative example 1

During the experiment in atmospheric conditions 100 g sample of corn stalks (taken from the fleshy texture) were tested using NaOH with a concentration of 10% and Na2SO3with a concentration of 15% in the temperature range of about 150°for 2, 3 and 4 hours, respectively. After filtering the boiled sample using sieves with openings 100 mesh residue was besieged in the water to neutralize approximately one day and was dried at 80°C for 5 days. The dried product was intended for use as a cellulosic material. Thus obtained the finished product had the Assu 65,4, 63,2 g and 62.3 g as a result of processing 15%NaOH at 150°for 2, 3 and 4 hours, respectively; and 68,34 g, 65,12 g 62,7 and g in the processing of a 15%solution of PA2SO3at 150°for 2, 3 and 4 hours, respectively. Thus, quantitative yield was about 65%. One hundred (100) grams of boiled sample was filtered through a sieve having openings 100 mesh, and the residue was besieged in the water for approximately one day with subsequent refining paper pulp. The finished product was intended for use as a cellulosic material, but the formation of paper from him was not made.

To calculate the output when cooking a sample of corn stalks, cooked under appropriate conditions of cooking, washed, torn in the machine to break the fiber at a speed of 3000 rpm and dried at 80°C for 5 hours and weighed. Exit when cooking asked by the following equation:

Example 1

In the process of cooking at high pressure according to the present invention in a rotary cooker with electric heater (pressure 0-10 kg/cm2temperature 0-200°With a capacity of 40 liters) was added to 500 g of the sample of corn stalks and cooked with a ratio of liquid (mass to mass) from 4:1 to 6:1 (mass of water cooking solution to the mass of dry sample) and mA is the maximum cooking temperature, comprising 150°C, for 1.5 to 4 hours, in accordance with alkaline cooking method.

In particular, in the first stage of the method of cooking soda in a rotary cooker with electric heater (pressure 0-10 kg/cm2temperature 0-200°With a capacity of 40 liters) was added to 500 g of the sample and was treated with 15%NaOH solution at a fixed ratio of the liquid (mass to mass), constituting 4:1 (mass of water cooking solution to the mass of dry sample), and the maximum temperature of cooking, comprising 150°C for 1.5 hours. Found that thickening of the corn stalks were underdone and restored to its original status, which complicated the use of the material obtained as a pulp. However, in the second stage of the method of cooking soda in a rotary cooker with electric heater (pressure 0-10 kg/cm2temperature 0-200°With a capacity of 40 liters) was added to 500 g of the sample was treated with 20%NaOH solution at a fixed ratio of the liquid (mass to mass), which constituted 6:1 (mass of water cooking solution to the mass of dry sample), and at a maximum temperature of cooking, comprising 150°C, for 3 hours. As a result, the corn stalks were well-cooked, making it possible to obtain cellulose pulp with access 21-35 wt.%.

Example 2/p>

Sample stems were subjected to alkaline cooking using the first cooking liquid, consisting of a 14%aqueous solution of Na2SO3and 4%PA solution2CO3at a fixed ratio of the liquid (mass to mass), constituting 4:1 (mass of water cooking solution to the mass of dry sample), and the maximum temperature of cooking, comprising 150°C, for 2 hours. Sample stems are not cooked properly with obtaining cellulose. Therefore, the sample stems were subjected to alkaline cooking using the second cooking liquid, consisting of a 28%aqueous solution of Na2SO3and an 8%aqueous solution of Na2CO3at a fixed ratio of the liquid (mass to mass), which constituted 6:1 (mass of water cooking solution to the mass of dry sample), and the maximum temperature of cooking, comprising 150°C, for 4 hours. As a result, the corn stalks are well-cooked, allowing the pulp mass with access 26-41 wt.%.

Example 3

Carried out the same procedure as described in Example 1, except that 500 g of the sample stems were subjected to alkaline cooking using a cooking solution consisting of 10%NaOH solution, a 20%aqueous solution of Na2SO3a 4%solution of Na2CO3and 0.1%of anthraquinone, when fixierungsmethoden liquid (weight to weight) comprising 6:1 (mass of water cooking solution to the mass of dry sample), for 3 hours. Pulp output was approximately 23-38 wt.%.

Example 4

Carried out the same procedure as described in Example 1, except that 500 g of the sample stems were subjected to sulphate cooking using a cooking solution consisting of 20%NaOH solution and a 15%aqueous solution of Na2S, for a fixed ratio of the liquid (mass to mass), which constituted 6:1 (mass of water cooking solution to the mass of dry sample), for 1.5 hours. Pulp output was approximately 25-32 wt.%.

Example 5

The first refining paper pulp and paper making

Besieged thirty (30) grams of cooked dry sample in water at a concentration of 10% (weight to weight) for at least 2 hours and added to the apparatus for grinding - mill for grinding PFI (grinding conditions: a pressure of 1.8 kg/cm2the gap 0.3 mm), with subsequent grinding of sulphate pulp at 500 rpm or alkaline sulfite pulp at 1100 rpm to get 40. SR (Schopper-Riegler).

Example 6

The pulp bleaching

As a bleaching agent used sodium hypochlorite (NaClO) and calcium hypochlorite (CA(lO)2) was added sodium hydroxide and sodium silicate to obtain a pH of 9-11. The concentration of the pulp found the ü in the range of 4-6% at the reaction temperature, 40°and in the range of 10-16% at 35°C.

After the stage of bleaching pulp remaining alkaline component was extracted, reaching concentrations of pulp 10-20% at 45-80°C for 1-2 hours.

Types of pulp produced in the examples were processed in sheets of paper using a special listwidgetdialog apparatus (manual listwidgetdialog apparatus production company TMI Inc. 173 mm in diameter).

Example 7

Measurements of physical properties of four varieties of cellulose (cellulose mass), i.e. soda pulp sulphate pulp, alkaline sulfite pulp and sulfite pulp obtained by using the examples above, which measure the physical properties. To improve the physical properties and increase the use of pulp from cornstalks, every 40 wt.% these individual types of cellulose were mixed with about 60 wt.% bleached Kraft pulp from coniferous wood. The cellulose measured to determine the specific volume, tensile strength, resistance to punching shear, fracture resistance and tear resistance. The results are presented in tables 1 and 2.

As described above, in the present invention, a method for producing cellulose mass is, in particular, the method of obtaining pulp from cornstalks, comprising the steps of cooking, washing, screening, water separation, bleaching, refining paper pulp and drying is carried out under mild conditions, which have an insignificant impact on the environment. Using corn stalks as raw material for paper pulp can exclude the import of raw wood, to save foreign currency, to increase income from agriculture and to promote the production of high quality paper.

1. The method of obtaining pulp from cornstalks, namely, that shredded corn stalks, cook, grind, is dispersed, is formed into paper and dried the sheets of paper, and the cooking is carried out at a ratio of aqueous solution of the reagent to the material cornstalks, sostavlyayuschim from 3:1 to 6:1, at the reaction temperature of 120-200°within 1.5-4 hours

2. The method according to claim 1, characterized in that it further bleach the pulp mass.

3. The method according to claim 1, characterized in that exercise sulphate cooking, sulphite cooking, alkaline boiling or cooking soda.

4. The method according to claim 1, characterized in that the injected water-soluble polymer material containing polyvinyl alcohol or polyacrylamide.

5. The method according to claim 1, characterized in that it further in the W ill result Supplement, starch-containing agent for hardening the paper, the agent for enhancing fibers, fluorescent bleach or polymer electrolyte.



 

Same patents:

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SUBSTANCE: aqueous suspension of at least one filler or mineral contains natural carbonate, polymeric dispersing agent as stabilizer of suspension viscosity, product of natural carbonate treatment with gaseous CO2, and product of natural carbonate reaction with at least one medium or strong H3O+-donors, has pH more than 7.5 at 200C. As natural carbonate suspension contains calcium carbonate (e.g., marble, calcite, carbonate-containing dolomite, chalk, ore mixtures thereof with talcum, and/or TiO2, MgO, or other minerals inert to H3O+-donors). As H3O+-donors suspension contains H2SO3, HSO

-4
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EFFECT: paper with decreased mass at constant surface.

33 cl, 1 dwg, 2 tbl, 8 ex

The invention relates to the pulp and paper industry and can be used in the manufacture of paper for corrugated cardboard

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1 tbl, 5 ex

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EFFECT: improved quality of cellulose, improved environmental safety of process, and reduced power consumption.

1 tbl, 4 ex

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