JP2012172287A - Papermaking method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a papermaking technique in which drying load is reduced in a dryer part.SOLUTION: A papermaking method comprises the steps of: performing papermaking from a paper material using both talc and rosette-type calcium carbonate as a filler; coating obtained paper with a surface treatment solution by a pond type size press; and drying the paper coated with the surface treatment solution by a multi cylinder dryer.

Description

  The present invention relates to a paper manufacturing method. More specifically, the present invention relates to a paper manufacturing method with reduced drying load.

  In general, paper is produced from a fiber suspension in which pulp fibers are suspended in water. In the manufacture of paper, pulp materials obtained from wood chips and waste paper are prepared by adding fillers and various chemicals such as sizing agents, paper strength enhancers, and retention agents as needed. It is manufactured by spraying this stock onto the wire from the head box, forming a wet paper (web) while dewatering at the wire part, squeezing water at the press part, and further drying the wet paper at the dryer part . In particular, a large amount of energy is consumed because a large amount of heat is required in the dryer part in order to dry the wet paper.

  Therefore, if a wet paper that is easy to dry can be obtained, the drying load on the dryer part is reduced, which not only reduces costs, but also meets energy savings and recent environmental awareness. If the drying load on the dryer part can be reduced, the paper can be dried with less energy when compared at the same speed, and the paper can be dried at higher speed when compared with the same energy. Productivity is improved.

  In general, in order to reduce the drying load, it is known to increase the freeness (freeness) of pulp as a raw material and increase the dewaterability of the stock. Non-Patent Document 1 describes freeness (freeness) for evaluating the degree of water drainage from pulp as an index representing the degree of beating, and it is described that the value decreases as the beating is strengthened. Document 2 describes that when beating progresses, water breakage becomes worse and it becomes difficult to make paper in the paper making process. In other words, increasing the freeness (freeness) means increasing the gaps between the fibers and making it easier for water to escape. This allows dehydration as much as possible in the wire part and press part, and in the dryer part. Can reduce the drying load. Further, Non-Patent Document 3 describes that the cost of removing the moisture is higher in the latter in pressing with a press and overheating with a dryer.

Pulp and Paper Manufacturing Technology Series 11 Introduction to Manufacturing Technology Pulp and Paper Technology Association (Page 35) Pulp and paper manufacturing technology series 11 Preparation of paper materials Pulp and paper technology association (page 12) Pulp and Paper Manufacturing Technology Series 6 Paper Making Paper and Pulp Technology Association (page 263)

  As described above, paper can be efficiently manufactured by reducing the drying load in the dryer part. However, although the drying load on the dryer part can be reduced by a conventional method for increasing the drainage, this method increases the voids between the fibers, so that water easily enters at the same time. In general, for the purpose of improving the surface strength and size of the paper, after wet paper is dried with a pre-dryer, the surface treatment liquid (size liquid) is applied to the paper with a size press and further dried with an after dryer. Is done. When the paper is surface-treated with a size press, if a paper material with excellent freeness is used, dehydration at the wire part is performed efficiently, but the amount of liquid absorbed by the size press increases. The drying load on the dryer part, particularly the after dryer, increases.

  In particular, when a pound type size press is used as the size press, the paper passes through the surface treatment liquid pound, and the surface treatment liquid easily penetrates into the inside of the paper, which greatly increases the drying load in the after dryer. The above-mentioned problem becomes remarkable.

  Therefore, the conventional technique of improving the dewaterability by increasing the freeness of the stock and increasing the gaps between the fibers cannot sufficiently reduce the drying load when performing size press.

Moreover, in order to reduce the drying load in the dryer part, it is possible to consider a facility from the standpoint of introducing a special device. However, such a measure requires a large capital investment.
In view of the situation as described above, the object of the present invention is to develop a technique for making paper while suppressing an increase in drying load even when performing size press by devising a paper material as a raw material. It is.

  As a result of intensive studies by the inventor in order to solve the above-mentioned problems, it has been found that by using Rosetta-type calcium carbonate and talc as an internal filler, the drying load in the dryer part can be reduced, and the present invention is completed. It came.

  That is, in the paper manufacturing method of the present invention, a step of paper-making from a paper material using talc and rosetta-type calcium carbonate as a filler, a step of applying a surface treatment liquid to the paper-made paper by a pound-type size press, The paper is manufactured by a method including a step of drying the paper coated with the surface treatment liquid with a multi-cylinder cylinder dryer.

  According to the present invention, even when a surface treatment liquid is applied to paper with a pound-type size press, the drying load in the dryer part is reduced and the operation efficiency is greatly improved without introducing a special apparatus. be able to.

  The paper making method according to the present invention includes a step of making paper from a paper stock using talc and rosetta type calcium carbonate as a filler, a step of applying a surface treatment liquid to the paper made by a pound size press, and a surface treatment Drying the coated paper with a multi-cylinder cylinder dryer. According to the paper making method of the present invention, it is possible to reduce the drying load in the dryer part and to efficiently manufacture paper. From another point of view, the present invention can also be grasped as a method for reducing the drying load in the production of paper.

In the ChoNaru present invention of the stock, in combination with talc and rosette type calcium carbonate as a filler to be added to the stock. In the present invention, when talc and rosetta-type calcium carbonate are used in combination, the details of the reason why the paper drying load is reduced are not clear, and the present invention is not restricted by the following assumptions, but merely increases the freeness of the pulp. In the conventional technology, although the dewaterability is improved, the amount of liquid absorbed by the size press increases and the load on the dryer increases. On the other hand, by using a specific filler in combination as in the present invention, the dewaterability of the paper stock is increased. Furthermore, it is presumed that the amount of liquid absorption at the size press is suppressed from becoming too large, and as a result, the drying load at the dryer part is reduced.

In the present invention, talc is used as an internal filler. Talc, magnesium hydrated silica _{(3MgO · 4SiO 2 · H 2} O) as a main component, having a layered structure with a layer of silica-magnesium hydroxide during the silica layer. It is also called talc, and its main production areas are China, South Korea, the United States and Australia. In the papermaking field, the use of talc as an internal filler is said to have the effect of improving opacity, smoothness, printing suitability, and the like. In the present invention, the average particle size of talc is not particularly limited, but is preferably 0.5 μm or more, more preferably 1.5 μm or more, and further preferably 5 μm or more from the viewpoint of yield. Further, from the viewpoint of paper smoothness, the average particle diameter of talc is preferably 40 μm or less, and more preferably 20 μm or less. In the present invention, the amount of talc used is not particularly limited, but the ratio of rosetta-type calcium carbonate: talc is preferably 50:50 to 99: 1 with respect to the rosetta-type calcium carbonate used in combination, and 60:40 to 90:10 is preferable. More preferred. This is because if the amount of talc used is too large, the opacity of the paper may decrease, whereas if the amount of talc used is too small, the effect of the present invention will be reduced.

  In the present invention, rosette type calcium carbonate is used together with talc as an internal filler. As the shape of calcium carbonate used for papermaking, needle shape, columnar shape, spindle shape, spherical shape, cubic shape, rosette type and the like are known, but in the present invention, rosette type calcium carbonate is used. Rosetta-type calcium carbonate has a shape in which primary particles of calcite-based calcium carbonate or aragonite-based calcium carbonate are aggregated in a corrugated shape, and has a high specific surface area and oil absorption compared to other forms of calcium carbonate There is. The average particle size of the rosetta-type calcium carbonate used in the present invention is not particularly limited, but is preferably 1 to 10 μm, more preferably 1.5 to 7 μm, from the viewpoint of improving the opacity of the paper and effectively suppressing the back-through. Preferably, 2-5 micrometers is further more preferable. The shape and average particle size of the primary particles of rosetta-type calcium carbonate are not particularly limited, and primary particles such as needles, spindles, rice grains, columns, and flats can be used. The diameter is preferably from 0.01 to 10 μm, more preferably from 0.1 to 5.0 μm. The oil absorption amount of the rosetta type light calcium carbonate is not particularly limited, but is preferably 50 to 300 ml / 100 g, and preferably 90 to 150 ml / 100 g from the viewpoint of effectively improving the printability of paper. Particularly preferred.

  Rosetta type calcium carbonate can be used alone or in combination with a plurality of types of rosetta type calcium carbonate. Preferable examples of commercially available rosetta-type calcium carbonate include products such as Albuquer HO, Albuquer 5970, Albuquer LO (all are Specialty Minerals). The production method of Rosetta-type calcium carbonate is not particularly limited, but in the calcium carbonate production process, by adjusting the supply method of carbon dioxide or adding additives such as condensed phosphoric acid and its salt, the primary calcium carbonate It is generally produced by agglomerating particles into a rosetta shape.

  As described above, talc and rosetta-type calcium carbonate are used in combination in the present invention, but other known fillers can be further blended in the paper stock. The kind of filler to mix | blend is not specifically limited, The filler generally used in acidic papermaking or neutral papermaking can be used. For example, in the present invention, clay, silica, kaolin, calcined kaolin, deramikaolin, heavy calcium carbonate, light calcium carbonate, magnesium carbonate, barium carbonate, titanium dioxide, zinc oxide, silicon oxide, amorphous silica, hydroxylated Inorganic fillers such as aluminum, calcium hydroxide, magnesium hydroxide, zinc hydroxide, titanium oxide, bentonite; organic fillers such as urea-formalin resin, polystyrene resin, melamine resin, phenol resin, and fine hollow particles; More than one type can be used in combination. In addition, recycled fillers made from papermaking sludge, deinking floss, etc. can also be used.

  The blending amount of the filler in the paper material is preferably 2 to 30% by weight with respect to the pulp weight from the viewpoint of opacity and the like. Further, the filler content in paper (ash content in paper) is desirably 10% by weight or more, and desirably 40% by weight or less. In particular, when paper having a high filler content and a high filler content in paper is produced, a decrease in dehydration becomes a serious problem. According to the present invention, the drying load can be reduced, which is preferable.

  The paper stock used in the present invention comprises a pulp raw material. There are no particular restrictions on the pulp raw material used. Besides wood pulp, non-wood pulp such as linter pulp, hemp, bagasse, kenaf, esparto grass, and straw, semi-synthetic fibers such as rayon and acetate, polyolefin, polyamide, polyester, etc. Synthetic fibers can be used. Specifically, it is commonly used as a papermaking raw material for printing paper such as mechanical pulp (MP), deinked pulp (DIP, also called waste paper pulp), hardwood kraft pulp (LKP), conifer kraft pulp (NKP), etc. Can be suitably used, and one or two or more of these are suitably used in combination. Examples of the mechanical pulp include groundwood pulp (GP), refiner groundwood pulp (RGP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), chemiground pulp (CGP), semi-chemical pulp (SCP), and the like. . Deinked pulp includes high-quality paper, medium-quality paper, low-grade paper, newspaper, flyers, magazines, and other sorts of waste paper, unsorted waste paper mixed with these, copy paper, thermal paper, and carbonless paper There is no particular limitation as long as it is a deinked pulp made from waste paper.

  Various internal additives may be added to the stock of the present invention as long as the effects of the present invention are not impaired. Internal additives include, but are not limited to, internal papers such as polyacrylamide polymers, polyvinyl alcohol polymers, cationic starches, various modified starches, urea / formalin resins, melamine / formalin resins, etc. Strength enhancer: Rosin-based sizing agent, AKD-based sizing agent, ASA-based sizing agent, petroleum-based sizing agent, neutral rosin sizing agent, and other internal sizing agents; sulfuric acid band, yield improver, UV inhibitor, fading prevention Agents, drainage improvers, coagulants, dyes and fluorescent dyes may be added.

Papermaking process In the present invention, the stock prepared as described above is appropriately diluted, and if necessary, removes foreign matter from the stock with a screen or a cleaner, and then sprays onto the papermaking wire from the headbox of the paper machine. Is done. The present invention can be applied to various paper machines and papermaking methods, and may be neutral papermaking or acidic papermaking. However, since rosetta type calcium carbonate is used, neutral papermaking is preferable. Specifically, in the present invention, the paper pH at the time of paper making is preferably 5.0 to 9.0, and more preferably 6.0 to 8.0.

  The head box of the paper machine used in the present invention is not particularly limited, and various types of head boxes can be used. In general, a head box is a device that sprays raw material onto a wire in a stable state over the entire width of a paper machine. For example, a step diffuser type head box, a high turbulence type head box, an axle flow type head box, a module jet type head A box etc. can be mentioned. Among these, in the present invention, a module jet type head box which is a concentration dilution type head box (also referred to as a density control type head box) can be suitably used.

  Further, the paper machine used in the present invention is not particularly limited, and for example, it can be appropriately made with a long net paper machine, a twin wire paper machine, a gap former paper machine or the like. Examples of twin wire paper machines include gap formers and on-top formers.

  The present invention is not limited to the configuration of the wire part of the paper machine, and can be applied to wire parts having various configurations. In general, various dewatering elements and dewatering devices are arranged in the wire part of a paper machine to promote dewatering. Specifically, a foil blade, a suction box or the like is used, and in the case of an on-top twin wire, an upper dewatering device or the like is also installed. Although the yield of fine fibers varies depending on the conditions of these dehydrating elements and dehydrating apparatuses, the type and arrangement of these dehydrating elements and dehydrating apparatuses are not particularly limited in the present invention, and are within the normal operating range. Thus, these dehydrating elements can be appropriately selected and arranged.

  In the wire part, the yield of pulp and filler varies depending on the type of the wire, but the opening and weaving method of the wire used in the present invention is not particularly limited, and a commercially available wire can be used as appropriate. .

  Generally, wet paper (web) formed in a sheet shape by a wire part of a paper machine is sent to a press part and squeezed. In the present invention, the press form of the press part of the paper machine is not limited, and a public apparatus can be used, but it is preferable to use a shoe press in two or more stages. Further, the pressing conditions are not particularly limited, and can be appropriately set within a normal operation range.

Size Pressing Process In the present invention, a surface treatment liquid is applied to paper by a pound type size press. The pound-type size press is a type of size press in which the surface treatment liquid is applied to the paper surface by passing the web through a pound (surface) of the surface treatment liquid, for example, between a pre-dryer and an after-dryer. Installed. In general, in addition to the pound-type size press used in the present invention, a size press of a gate roll type or a rod metering type is known as the size press. These size presses allow paper to pass directly through the pound. The surface treatment liquid can be applied only to the vicinity of the surface of the paper using a roll or rod as a medium, so that the drying load in the after dryer is relatively small. However, in the pound-type size press, the surface treatment liquid in the pound and the paper are in direct contact with each other, so that the amount of liquid absorbed by the size press increases, and the drying load on the dryer part, particularly the after dryer, increases. According to the present invention, the drying load on the dryer part can be reduced even when paper is manufactured using such a pound-type size press.

  In the present invention, the surface treatment liquid for clear coating by a pound size press may contain a binder and a sizing agent. The type and composition of the surface coating agent for clear coating are not particularly limited, but as a binder for the purpose of enhancing the surface strength, raw starch, oxidized starch, esterified starch, cationized starch, enzyme-modified starch, aldehyde Starch, hydroxyethylated starch, hydroxypropylated starch, etc .; cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, methylcellulose; modified alcohols such as polyvinyl alcohol, carboxyl-modified polyvinyl alcohol; styrene-butadiene copolymer, polyvinyl acetate, Water-soluble polymer substances such as vinyl chloride-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, polyacrylic acid ester, and polyacrylamide can be used alone or in combination. Of these, application of hydroxyethylated starch or hydroxypropylated starch, which is excellent in the effect of improving surface strength, is most preferable. In addition, as a sizing agent for imparting water absorption resistance to paper, styrene acrylic acid, styrene maleic acid, olefinic compounds, acrylic (meth) acrylate compounds, rosin sizing agents, reactive sizes such as AKD and ASA, etc. A general surface sizing agent such as an agent can be used in combination.

  When a surface treatment agent containing a water-soluble polymer substance and a surface sizing agent is applied, the mixing ratio of the water-soluble polymer substance and the surface sizing agent may be within a public range, and is not particularly limited. Further, the coating amount of the water-soluble polymer substance and / or the surface sizing agent may be adjusted according to the use, and is not particularly limited.

Drying process In the present invention, the paper coated with the surface treatment liquid as described above is dried by a multi-cylinder cylinder dryer. The multi-cylinder cylinder dryer is configured by arranging a plurality of cylindrical cylinder dryers, and the paper is dried while the paper passes through the plurality of cylinder dryers in contact. In general, for drying paper, in addition to the multi-cylinder cylinder dryer of the present invention, for drying sanitary paper such as a Yankee dryer or tissue that dries while pressing wet paper against one large-diameter dryer (also called a Yankee). Air-through dryers, infrared dryers, and the like are known, but a multi-cylinder cylinder dryer is suitable for mass production because of its relatively high processing speed.

  The drying capacity of the multi-cylinder cylinder dryer can be controlled by the number of dryer cylinders and the vapor pressure. When the vapor pressure of the heating steam for heating the dryer cylinder is increased, the wet paper can be quickly dried at a high temperature. It is also possible to sufficiently dry the paper by slowing down the paper passing through the multi-cylinder cylinder dryer and increasing the contact time between the dryer and the paper, but this reduces the paper production efficiency. End up.

  In general, it is conceivable to dry a wet paper having a high drying load (a wet paper that is difficult to dry) by increasing the steam pressure of the heated steam or decreasing the paper making speed. Since the drying load in paper production can be reduced, the paper making speed can be increased if the steam pressure is constant, and the steam pressure of the heating steam can be saved if the paper making speed is constant. In any case, productivity is greatly improved.

Surface Treatment The paper produced in this way may be surface-treated with a calendar if necessary, or processed into a winder with a winder. These processes are not particularly limited, and can be performed by a known method. As a calendar device, for example, an ordinary calendar made of metal roll, a soft nip calender, and a high temperature soft nip calender are appropriately selected and within the controllable range of these devices according to the quality target value. What is necessary is just to set conditions.

  The paper produced as described above can be used as it is as a non-coated paper without being subjected to pigment coating, or it can be further coated with pigment to obtain a coated paper. When pigment coating is performed, the coating method and the composition of the pigment coating layer are not particularly limited. As the pigment, for example, an inorganic pigment such as kaolin, clay, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicate, colloidal silica, and satin white; an organic pigment such as plastic pigment is appropriately selected. Can be used. As the adhesive, synthetic adhesives such as styrene / butadiene latex and polyvinyl alcohol; starches, cellulose derivatives and the like can be conveniently selected and used. The ratio of the pigment and the adhesive may be within a public range and is not particularly limited. As the coating apparatus, for example, a blade coater, a bar coater, an air knife coater, a reverse roll coater, a curtain coater, a rod metering size press coater, a gate roll coater, or the like can be used.

Paper The paper obtained by the production method of the present invention can be used for various applications such as high-quality or medium-quality printing paper, newspaper paper, coated base paper such as art paper and cast coated paper, and information recording paper. In the case of printing paper, the printing method is not limited to offset printing, letterpress printing, etc., but since the present invention can be suitably applied to neutral papermaking and high-speed papermaking, the paper produced by the present invention is offset paper such as newsprint paper. Printing paper is preferred.

Although there is no limitation also about the basic weight of the paper manufactured by this invention, this invention is preferably applicable by papermaking of a thick thing with high basic weight. When the basis weight of the paper increases, the amount of moisture to be dried increases in proportion to the basis weight, so that the drying load increases. According to the present invention, the drying load can be efficiently reduced, so that thick paper can be made. When applied to the present invention, the effects of the present invention can be greatly enjoyed. Specifically, the present invention is preferably used when producing paper having a basis weight of 80 g / m ² or more, more preferably a basis weight of 100 g / m ² or more, and even more preferably a basis weight of 120 g / m ² or more. It can be suitably applied.

  Hereinafter, although an example is given and the present invention is explained, the present invention is not limited to this example. In the present specification, unless otherwise specified, parts and% represent parts by weight and% by weight, respectively, and numerical ranges are described as including the end points.

Manufacture of paper Cationic modified starch with 10% solids content to pulp solids and 1% solids content to pulp as an internal paper strength enhancer to pulp slurry prepared by disaggregating 100 parts hardwood bleached kraft pulp (CSF 500ml) A stock was prepared by addition. Filler composition (weight basis) is talc (lightweight: 97.0%, oil absorption: 120 ml / 100 g, average particle size: 2.0 μm, specific surface area: 2.5 m ² / cc) 85 parts by weight. 15 parts of whiteness 83.8%, oil absorption 53 ml / 100 g, average particle diameter 12.6 μm, specific surface area 0.62 m ² / cc) were used in combination.

Paper having various basis weights was produced from this stock by a machine having a configuration described later. Specifically, the above paper stock is sent to a module jet type head box, paper stock is sprayed onto the twin wire type paper making wire from the head box, paper is made, squeezed with a press part, dried with a predryer, and then bonded. Surface coating agent (hydroxyethylated starch solid content concentration 10%, surface sizing agent solids) containing hydroxyethylated starch and cationic surface sizing agent (styrene / acrylic ester copolymer) (Concentration 0.10%) is applied evenly on both the felt and wire sides (coating amount 2 g / m ² : total on both sides), and the moisture content of the paper is dried to 5% with an after dryer. Paper was produced so that the amount was 90 g / m ² , 120 g / m ² , 140 g / m ² , and 160 g / m ² .

  In this example, the vapor pressure of the steam for heating the cylinder dryer was made constant, and then the paper was manufactured by setting the moisture content of the finished paper to 5%. Therefore, if it is easy to dry and the water content of the paper easily reaches the target water content, the paper making speed can be increased.If the paper moisture content is difficult to dry and the water content of the paper is difficult to reach the target water content, the paper making speed is high. Lower.

Machine configuration The machine used in this example is composed of a head box, a wire part, a press part, a pre-dryer, a size press, and an after-dryer, the details of which are as follows.
・ Headbox: Module jet type ・ Wire part: Twin wire type ・ Press part: 3 presses ・ Predryer: Multi-cylinder cylinder dryer (28 cylinders)
・ Size press: Pound type size press ・ After-dryer: Multi-cylinder cylinder dryer (24 cylinders)
Test results The results of papermaking under the above conditions are shown in the following table. As is apparent from the table, when Rosetta-type charcoal and talc were used in accordance with the present invention, the average papermaking speed was improved by about 10 m / min or more. That is, as a result of reducing the drying load in the dryer part according to the present invention, it was possible to operate at a higher speed and to manufacture paper more efficiently.

Claims (2)

The process of making paper from a stock that uses talc and rosetta-type calcium carbonate as fillers;
Applying a surface treatment liquid to the paper made by a pound size press,
Drying the paper coated with the surface treatment liquid with a multi-cylinder cylinder dryer;
A method for producing paper, comprising: The method according to claim 1, which is a method for producing paper having a basis weight of 80 g / m ² or more.