Manufacturing method of sheet

Abstract

To suppress, in a sheet manufacturing method that includes a step of spraying a liquid to a surface of a sheet or a travelling body contacting with a sheet, unevenness of spraying a liquid to a surface of the sheet or an unevenness of wear of a surface of the travelling body.SOLUTION: In a sheet manufacturing method that includes a step of spraying a liquid to a surface of a sheet or a travelling body contacting with a sheet, the liquid is sprayed in a fan shape with a longitudinal direction of an ejection pattern of the liquid intersecting a width direction of the sheet or the travelling body at an angle of less than 5 degrees.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing sheets of paper or the like. [Background technology]

[0002] BACKGROUND ART Conventionally, a liquid containing a paper strength agent or the like is sprayed onto a wet paper moving in a paper machine in order to increase the paper strength or the like.

[0003] Patent document 1 discloses that when spraying a chemical solution containing a water-soluble polymer in a fan shape onto the surface of a wet paper web on a Yankee dryer, the chemical solution containing a water-soluble polymer is sprayed onto the wet paper web so that multiple fan shapes intersect with the width direction of the wet paper web at angles of 5 to 30 degrees and the surfaces of each fan shape are parallel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-150731 Summary of the Invention [Problem to be solved by the invention]

[0005] According to Patent Document 1, the spraying method described therein is said to be able to suppress uneven application of the chemical solution, but there is room for improvement.

[0006] Furthermore, Patent Document 1 assumes that the chemical solution will be sprayed onto the wet paper on a roll-shaped Yankee dryer, and does not anticipate spraying the chemical solution directly onto the surface of the Yankee dryer.However, in methods for manufacturing sheets of paper or the like, there are cases where liquid is sprayed directly onto the surfaces of various rolls that come into contact with the sheet, and in such cases, uneven wear of the roll surfaces becomes a problem.

[0007] A first object of the present invention is to suppress unevenness in the ejection of liquid onto the surface of a sheet, such as paper, in a sheet manufacturing method that includes a step of ejecting various liquids onto the surface of the sheet.

[0008] A second object of the present invention is to suppress uneven wear on the surface of a running body such as a roll that comes into contact with a sheet such as paper in a sheet manufacturing method that includes a step of spraying various liquids onto the surface of the running body. [Means for solving the problem]

[0009] The first and second objects of the present invention are to provide a method for manufacturing a sheet, which includes a step of spraying a liquid onto the surface of a sheet or a traveling body that comes into contact with the sheet, The liquid is sprayed in a fan shape, This can be achieved by a sheet manufacturing method in which the longitudinal direction of the liquid spray pattern intersects with the width direction of the sheet or the traveling body at an angle of less than 5 degrees.

[0010] It is preferable that the longitudinal direction of the liquid spray pattern is parallel to the width direction of the sheet or the traveling body.

[0011] The fan-shaped spray angle is preferably 50 to 120 degrees.

[0012] It is preferable that the liquid is sprayed in a plurality of sectors, and that the sectors partially overlap each other.

[0013] The spraying is preferably carried out by a fixed nozzle.

[0014] Preferably, the fixed nozzle is provided at the end of a bifurcated pipe.

[0015] The fixed nozzle is preferably a flat nozzle.

[0016] Preferably, the liquid comprises water.

[0017] The sheet may be paper.

[0018] The traveling body may be a roll.

[0019] The roll may be a dryer roll.

[0020] The roll may be a size press roll. [Effects of the Invention]

[0021] According to the present invention, in a sheet manufacturing method that includes a step of spraying various liquids onto the surface of a sheet such as paper, it is possible to suppress uneven spraying of the liquid onto the surface of the sheet.

[0022] Furthermore, the present invention can suppress uneven wear on the surface of a running body such as a roll in a sheet manufacturing method that includes a step of spraying various liquids onto the surface of the running body that comes into contact with a sheet such as paper. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 10 is a diagram showing an example of a fan-shaped injection. [Figure 2A] FIG. 10 is a diagram showing a form in which liquid is sprayed in a fan shape toward the surface of a cylindrical traveling body. [Figure 2B] 10A and 10B are diagrams showing another form in which liquid is sprayed in a fan shape toward the surface of a cylindrical running body. [Figure 3] 1 is a diagram illustrating a schematic diagram of an example of a paper machine. [Figure 4] FIG. 2 is a diagram schematically illustrating an example of a shower device 32. [Figure 5] FIG. 10 is an enlarged front view of flat nozzles 321b and 321c. [Figure 6] 10 is a diagram showing an embodiment in which the longitudinal direction of the liquid spray pattern is parallel to the rotation axis of the dryer roll 31 or the width direction x of the wet paper on the dryer roll 31. FIG. [Figure 7] FIG. 1 is a schematic diagram illustrating an embodiment of spraying liquid onto the surface of a size press roll in a size press in a paper machine. DETAILED DESCRIPTION OF THE INVENTION

[0024] In the present invention, the term "sheet" refers to a planar object, particularly a long planar object, and examples thereof include paper, nonwoven fabric, woven fabric, film, metal foil, etc. The material of the sheet is not particularly limited, and examples thereof include natural materials such as cellulose fibers derived from wood, artificial materials such as synthetic resins, inorganic materials such as metals, or combinations thereof. The sheet may be either porous or non-porous. The sheet is preferably made of fiber, more preferably paper or nonwoven fabric, and even more preferably paper.

[0025] In the present invention, the term "traveling body" refers to a member capable of traveling, and examples thereof include a dryer roll, a size press roll, a wire, a felt, a canvas, etc. in a papermaking machine, or a roll used in a spray coating method. The type of movement of the traveling body is not particularly limited, but examples thereof include rotation and winding. A cylindrical roll (roller) is preferred as the traveling body, and a dryer roll or a size press roll used in the papermaking process is more preferred.

[0026] After extensive research, the inventors have discovered that when various liquids are sprayed (or ejected, discharged, sprayed or scattered) in a fan shape onto the surface of a sheet such as paper, if the fan shape intersects with the width direction of the sheet at a large angle, particularly when the sheet is curved, the difference in spray amount and / or spray pressure between the center and edges of the spray pattern on the surface of the sheet becomes large, resulting in greater spray unevenness.

[0027] Therefore, the inventors decided to suppress uneven spraying by ensuring that when various liquids are sprayed in a fan shape onto the surface of a sheet such as paper, the fan shape does not intersect with the width direction of the sheet at a large angle, and by preventing a large difference in spray amount and / or spray pressure between the center and edges of the spray pattern on the surface of the sheet even if the sheet is curved.

[0028] This allows the liquid to be sprayed more uniformly onto the surface of a sheet in a sheet manufacturing method that includes a step of spraying various liquids onto the surface of a sheet such as paper.

[0029] Furthermore, the inventors have decided that when various liquids are sprayed in a fan shape onto the surface of a running body such as a roll that comes into contact with a sheet of paper or the like, the fan shape should not intersect with the width direction of the surface of the running body at a large angle, and that even if the surface of the running body is curved, the difference in spray amount and / or spray pressure between the center and ends of the spray pattern on the surface of the running body should not be large, thereby suppressing spray unevenness.

[0030] When liquid is sprayed onto the surface of a running body for a long period of time, the surface will wear out. However, the present invention can reduce the difference in spray amount and / or spray pressure between the center and ends of the spray pattern on the surface of the running body, thereby reducing uneven wear on the surface of the running body.

[0031] This allows for more uniform wear on the surface of a running body such as a roll that comes into contact with a sheet such as paper in a sheet manufacturing method that includes a step of spraying various liquids onto the surface of the running body.

[0032] Here, "contact" includes not only direct contact (e.g., physical contact) between a sheet such as paper and the surface of a running body such as a roll, but also indirect contact via various viscous liquids so that the movement of the running body can be transmitted to the sheet. An example of indirect contact is contact between a size press roll and paper via a thin liquid coating film that can occur in the size press of a papermaking machine.

[0033] Thus, the present invention provides a method for manufacturing a sheet, which includes a step of spraying a liquid onto the surface of a sheet or a traveling body that comes into contact with the sheet, The liquid is sprayed in a fan shape, In the sheet manufacturing method, the longitudinal direction of the liquid spray pattern intersects with the width direction of the sheet or the traveling body at an angle of less than 5 degrees.

[0034] In the present invention, the term "fan shape" refers to the side shape of the three-dimensional shape formed by the ejected droplets of liquid, and resembles an open folding fan. The central angle of the fan as viewed from the side is called the ejection angle. Note that the destination of the ejected droplets of liquid does not necessarily form a circular arc of a fan in the mathematical sense.

[0035] The term "spray pattern" refers to a pattern formed by droplets of the sprayed liquid on a surface that the droplets reach. In the present invention, the term "spray pattern" refers to a pattern or figure formed by the sprayed liquid on the surface of a sheet or a traveling body.

[0036] Figure 1 shows an example of a fan-shaped injection.

[0037] In Fig. 1, liquid is sprayed in a fan shape from nozzle N, and droplets of the sprayed liquid form a spray pattern SP on the surface they reach. In Fig. 1, the center of the spray pattern SP in Fig. 1 is represented by C, and the ends are represented by E.

[0038] In a fan-shaped jet, unlike a conical jet, the cross section of the jet is not circular, but rather has a shape such as an ellipse or spindle with a longitudinal direction. Therefore, the jet pattern SP formed by the liquid droplets on the surface where the droplets land is also not circular, but has a shape such as an ellipse or spindle with a longitudinal direction. Note that the longitudinal direction of an ellipse is an extension of the long axis of the ellipse, and the longitudinal direction of a spindle is an extension of the line connecting the two ends of the spindle.

[0039] Normally, the number of liquid droplets that reach the center C of the spray pattern SP is greatest, and the number is smallest at the fan-shaped end E. That is, in the spray pattern SP, the spray amount is large at the center C and small at the end E. Also, in the spray pattern SP, the spray pressure is high at the center C and low at the end E.

[0040] In the present invention, the crossing angle between the longitudinal direction of the liquid spray pattern and the width direction of the sheet or traveling body is suppressed to less than 5 degrees.

[0041] In the present invention, the width direction of a sheet or a traveling body means the direction perpendicular to the shortest length of the surface of the sheet or the traveling direction of the traveling body. Therefore, if the sheet is rectangular (or long), the width direction of the sheet is the direction perpendicular to the longitudinal direction of the sheet. Furthermore, if the traveling body is rotatable and cylindrical, the width direction of the traveling body is the direction of the generatrix or rotation axis.

[0042] Figure 2 shows a configuration in which liquid is sprayed in a fan shape toward the surface of a cylindrical running body.

[0043] For the sake of simplicity, in FIGS. 2A and 2B, the injection patterns are represented by line segments, the lengths of which are indicated by W1 and W2, respectively.

[0044] Figure 2A shows a perspective view (left) and a top view (right) of the case where the crossing angle between the width direction x of the running body and the longitudinal direction of the liquid spray pattern is 0 degrees, i.e., the width direction x of the running body and the longitudinal direction of the liquid spray pattern are parallel.

[0045] On the other hand, Figure 2B shows a perspective view (left) and a top view (right) of a case where there is an intersection angle θ between the width direction x of the running body and the longitudinal direction of the liquid spray pattern, i.e., a case where the width direction x of the running body intersects with the longitudinal direction of the liquid spray pattern.

[0046] Because the surface of the cylindrical running body is curved, as is clear from Fig. 2, the length of the spray pattern is longer in Fig. 2B, where the width direction x of the running body and the longitudinal direction of the liquid spray pattern intersect, compared to Fig. 2A, where the width direction x of the running body and the longitudinal direction of the liquid spray pattern are parallel. In other words, W2 in Fig. 2B is longer than W1 in Fig. 2A.

[0047] As is clear from FIG. 1, the injection amount and injection pressure are lower at the ends of the injection pattern than at the center, whereas in FIG. 2B the ends of the injection pattern are further away from the center than in FIG. 2A.

[0048] Therefore, when spraying liquid onto the surface of a sheet on a running body, the difference in spray amount and spray pressure between the center and edge of the spray pattern is larger in Fig. 2B than in Fig. 2A, resulting in greater spray unevenness on the surface of the sheet. Also, when spraying liquid directly onto the running body, the difference in spray amount and spray pressure between the center and edge of the spray pattern is larger in Fig. 2B than in Fig. 2A, resulting in greater spray unevenness on the surface of the running body.

[0049] These large jetting irregularities increase the non-uniformity of the physical properties of the sheet surface and the non-uniformity of the wear on the surface of the running body.The increase in jetting irregularities becomes significant when the crossing angle θ in Figure 2B is 5 degrees or more.

[0050] Therefore, in the present invention, the crossing angle θ in Fig. 2B is set to less than 5 degrees, and the difference in the spray amount and spray pressure between the center and end of the spray pattern on the surface of the sheet or traveling body is not too large, thereby suppressing spray unevenness. The crossing angle θ is preferably less than 4 degrees, more preferably less than 3 degrees, even more preferably less than 2 degrees, even more preferably less than 1 degree, and particularly preferably 0 degrees (see Fig. 2A).

[0051] This allows the liquid to be sprayed more uniformly onto the surface of a sheet in a sheet manufacturing method that includes a step of spraying various liquids onto the surface of a sheet such as paper, and also allows the surface of the running body to be worn more uniformly in a sheet manufacturing method that includes a step of spraying various liquids onto the surface of a running body such as a roll that comes into contact with a sheet such as paper.

[0052] In addition, Patent Document 1 states that the fan shape formed by spraying the water-soluble polymer intersects with the width direction of the wet paper at an angle of 5 to 30 degrees, and since it is essential that the intersection angle θ in Figure 2B be 5 to 30 degrees, there are clear obstacles to making the intersection angle θ less than 5 degrees.

[0053] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the up, down, left, and right directions are set for the convenience of explaining the embodiment, and do not limit the configuration or usage of the present invention.

[0054] FIG. 3 is a diagram schematically illustrating an example of a paper machine.

[0055] In the paper machine shown in Figure 3, the stock S supplied from a supply source (not shown) is made into a wet paper web WP in the wire part 1. Next, the wet paper web WP is dewatered in the press part 2 and supplied to the dryer part 3. Note that the press rolls in the press part 2 are not shown in Figure 3.

[0056] The stock S is not particularly limited, and examples of the raw material for the stock S include wood pulp, non-wood pulp, and a mixture thereof.

[0057] Examples of wood pulp include chemical pulps such as hardwood pulp (hardwood kraft pulp (LKP)), softwood pulp (softwood kraft pulp (NKP)), sulfite pulp, dissolving pulp (DP), soda pulp (AP), unbleached kraft pulp (UKP), and oxygen-bleached kraft pulp (OKP). Other examples include semi-chemical pulps such as semi-chemical pulp (SCP) and chemi-groundwood pulp (CGP), and mechanical pulps such as groundwood pulp (GP), and thermomechanical pulp (TMP, BCTMP).

[0058] Examples of non-wood pulp include cotton pulp such as cotton linter and cotton lint, hemp, wheat straw, bagasse, and the like.

[0059] In addition to virgin pulp, recycled paper pulp can also be used as the raw material for the paper stock S. Recycled paper pulp is pulp produced from paper that has been produced through papermaking. Examples of recycled paper pulp include deinked pulp made from used paper. The type of recycled paper is not particularly limited, but examples include paper cartons for packaging liquids such as milk cartons, cardboard, and various types of printed paper such as newspapers and magazines.

[0060] In the dryer part 3, the wet paper web WP is supplied to the surface of a dryer roll 31 such as a Yankee dryer. The dryer roll 31 is a high-temperature cylindrical member that rotates to transport the wet paper web WP. The wet paper web WP is heated and dried on the dryer roll 31 during transport, and is then supplied to the next process.

[0061] In the paper machine shown in FIG. 3, a shower device 32 for spraying liquid is arranged at a position facing the wet paper web WP on the dryer roll 31, and the liquid is sprayed onto the surface of the wet paper web WP.

[0062] The type of liquid to be sprayed is not particularly limited, but is preferably volatile and contains water. The liquid to be sprayed may be a dispersion, a liquid solute, a solution, or a solvent only.

[0063] Furthermore, the sprayed liquid may contain various chemicals, such as, but not limited to, paper strength agents, sizing agents, dyes, pigments, and fillers.

[0064] Examples of the paper strength agent include water-soluble polymers.

[0065] Examples of the water-soluble polymer include a nonionic polymer, an anionic polymer, a cationic polymer, and an amphoteric polymer.

[0066] In addition to the drug, the liquid may contain auxiliary agents such as a chelating agent, a pH adjuster, a preservative, an antifoaming agent, a dispersant, a viscosity adjuster, a lubricant, and an anti-slip agent.

[0067] Fig. 4 is a diagram schematically illustrating an example of the shower device 32 shown in Fig. 3. Note that the wet paper web present on the dryer roll 31 is not shown.

[0068] In the example shown in Fig. 4, shower device units 321, 322, and 323 are arranged above dryer roll 31. Although only three shower device units 321, 322, and 323 are shown in Fig. 4, a large number of shower device units (not shown) are arranged along the rotation axis direction of dryer roll 31.

[0069] 4, shower device units 321, 322, and 323 include bifurcated pipes 321a, 322a, and 323a, respectively. For convenience of maintenance and inspection, bifurcated pipes 321a, 322a, and 323a are preferably made up of a combination of multiple members.

[0070] In Figure 4, one end of the upper side of the bifurcated pipes 321a, 322a, and 323a is connected to a liquid supply pipe (not shown), and liquid to be sprayed onto a wet paper (not shown) on the dryer roll 31 is supplied through the liquid supply pipe.

[0071] On the other hand, flat nozzles 321b, 321c, 322b, 322c, 323b, and 323c are provided at the other two lower ends of bifurcated pipes 321a, 322a, and 323a, and the liquid supplied to bifurcated pipes 321a, 322a, and 323a is sprayed in a fan shape from flat nozzles 321b, 321c, 322b, 322c, 323b, and 323c.

[0072] The flat nozzles 321b, 321c, 322b, 322c, 323b, and 323c may be either single-fluid or dual-fluid nozzles. Single-fluid nozzles can easily apply high injection pressure to the injected droplets. Dual-fluid nozzles can easily produce small droplets by using gas such as air.

[0073] By using the bifurcated pipes 321a, 322a, 323a, the number of flat nozzles that can be arranged can be increased compared to when they are not used.

[0074] It is preferable that the flat nozzles 321b, 321c, 322b, 322c, 323b, and 323c are positioned directly opposite the wet paper web (not shown) on the dryer roll 31.

[0075] Furthermore, it is preferable that the flat nozzles 321b, 321c, 322b, 322c, 323b, and 323c are arranged at equal intervals along the axial direction of the dryer roll 31.

[0076] The spray angle θ1 of the fan-shaped liquid sprayed from flat nozzles 321b, 321c, 322b, 322c, 323b, and 323c shown in FIG. 4 is preferably 50 to 120 degrees, more preferably 60 to 115 degrees, even more preferably 70 to 110 degrees, and even more preferably 80 to 100 degrees.

[0077] It is preferable that the liquid sprayed from the flat nozzles 321b, 321c, 322b, 322c, 323b, and 323c be sprayed so that the fan-shaped droplets of the liquid partially overlap, as shown in Fig. 4. That is, it is preferable that the liquid be sprayed in multiple fan-shaped shapes, and that the multiple fan-shaped shapes partially overlap. As a result, even if the spray amount distribution of each of the flat nozzles 321b, 321c, 322b, 322c, 323b, and 323c is a so-called mountain shape (i.e., the spray amount is large in the center and small at the ends in the spray pattern), the overlap of the ends can effectively suppress spray unevenness in the width direction of the dryer roll 31 or the wet paper web (not shown) on the dryer roll 31.

[0078] It is preferable that the flat nozzles 321b, 321c, 322b, 322c, 323b, and 323c are not movable and are fixed in position within the paper machine. That is, it is preferable that the flat nozzles 321b, 321c, 322b, 322c, 323b, and 323c are fixed nozzles. This allows the spray position relative to the dryer roll 31 or the wet paper (not shown) on the dryer roll 31 to be constant, allowing for stable spraying.

[0079] FIG. 5 is an enlarged front view of the flat nozzles 321b and 321c.

[0080] 5, flat nozzles 321b and 321c are equipped with slit-shaped jetting orifices 321d and 321e, respectively, and the angle θ2 formed between the rotation axis of the dryer roll (not shown) or the width direction x of the wet paper and the longitudinal extension line y of each jetting orifice is less than 5 degrees. θ2 is preferably less than 4 degrees, more preferably less than 3 degrees, even more preferably less than 2 degrees, even more preferably less than 1 degree, and particularly preferably 0 degrees. In other words, it is particularly preferable that the longitudinal extension line y of jetting orifices 321d and 321e be parallel to the rotation axis of the dryer roll (not shown) or the width direction x of the wet paper.

[0081] As a result, the longitudinal direction of the spray pattern of the liquid sprayed from the flat nozzles 321b, 321c intersects with the rotation axis of the dryer roll (not shown) or the width direction x of the wet paper at an angle of less than 5 degrees. The intersection angle is preferably less than 4 degrees, more preferably less than 3 degrees, even more preferably less than 2 degrees, even more preferably less than 1 degree, and particularly preferably 0 degrees. In other words, it is particularly preferable that the longitudinal direction of the spray pattern is parallel to the rotation axis of the dryer roll (not shown) or the width direction x of the wet paper.

[0082] FIG. 6 shows an embodiment in which the longitudinal direction of the liquid spray pattern is parallel to the rotation axis of the dryer roll 31 or the width direction x of the wet paper (not shown) on the dryer roll 31.

[0083] 6, the liquid spray pattern does not intersect with the rotation axis of the dryer roll 31 or the width direction x of the wet paper (not shown), so even if the dryer roll 31 and the surface of the wet paper (not shown) are curved, the difference in spray amount and spray pressure between the center and end of the spray pattern can be suppressed. Therefore, it is possible to suppress spray unevenness in the width direction x of the wet paper, and to enable more uniform spraying of liquid onto the surface of the wet paper.

[0084] On the other hand, when the longitudinal direction of the liquid spray pattern intersects with the rotation axis of the dryer roll 31 or the width direction x of the wet paper (not shown) on the dryer roll 31 at an angle of 5 degrees or more, the liquid spray pattern intersects with the rotation axis of the dryer roll 31 or the width direction x of the wet paper (not shown) at a relatively large angle, so the difference in spray amount and spray pressure between the center and end of each spray pattern becomes large. In other words, because the surfaces of the dryer roll 31 and the wet paper (not shown) are curved, the difference in spray amount and spray pressure between the center and end of the spray pattern becomes large. In that case, spray unevenness becomes large along the width direction x, making it difficult to spray the liquid uniformly on the surface of the wet paper.

[0085] In the embodiment shown in FIGS. 3 to 6, the fan shape and / or spray pattern of the liquid sprayed from each shower device unit 321, 322, 323 of shower device 32 can be adjusted by controlling factors such as the pressure of the liquid sprayed from each shower device unit 321, 322, 323, the shape of the spray opening of each flat nozzle 321b, 321c, 322b, 322c, 323b, 323c of shower device units 321, 322, 323, and the pressure of the liquid sprayed from each flat nozzle 321b, 321c, 322b, 322c, 323b, 323c.

[0086] In addition, the fan shape and / or spray pattern of the liquid sprayed from shower device units 321, 322, 323 can be adjusted by the branching position of each bifurcated pipe 321a, 322a, 323a of each shower device unit 321, 322, 323 of shower device 32, the spacing between each flat nozzle 321b, 321c, 322b, 322c, 323b, 323c, the distance between each flat nozzle 321b, 321c, 322b, 322c, 323b, 323c and the surface of the wet paper, etc.

[0087] In the embodiment shown in Figures 3 to 6, uneven spraying of liquid onto the surface of the wet paper can be suppressed, allowing the liquid to be sprayed more uniformly, so that the paper properties obtained by the liquid can be made more uniform on the surface of the paper.

[0088] In the embodiment shown in Figs. 3 to 6, the liquid is sprayed onto the surface of the wet paper WP present on the surface of the dryer roll 31, but the liquid may be sprayed onto a part other than the wet paper in the paper machine.

[0089] FIG. 7 is a diagram schematically illustrating an embodiment in which a liquid is sprayed onto the surface of a size press roll in a size press process in a paper machine.

[0090] In the example shown in Figure 7, paper P provided from a previous process (not shown) passes through a liquid reservoir 42 formed between two size press rolls 41a and 41b, and a thin coating film is formed on the surface of the paper P. The coating film then dries to become a coating layer, producing so-called coated paper.

[0091] The reservoir may contain a volatile medium such as water, as well as a surface sizing agent such as starch, carboxymethyl cellulose, or polyvinyl alcohol (PVA). The reservoir may also contain auxiliary agents such as antifoaming agents, preservatives, and antifungal agents.

[0092] 7, shower devices 43a and 43b are disposed above the size press rolls 41a and 41b in positions facing the roll surfaces, respectively, and liquid is sprayed (or squirted, discharged, sprayed, or scattered) in a fan shape onto the surfaces of the size press rolls 41a and 41b. Note that a shower device may be disposed above only one of the size press rolls 41a and 41b.

[0093] The liquid sprayed from shower devices 43a, 43b preferably has the same composition as the liquid stored in liquid reservoir 42, but may have a different composition. In any case, the liquid sprayed from shower devices 43a, 43b is preferably volatile and preferably contains water.

[0094] The configuration of shower devices 43a and 43b is the same as shower device 32 described with reference to FIGS. 3 to 6, so a repeated description will be omitted.

[0095] 7, the longitudinal direction of the spray pattern of the liquid sprayed from the shower devices 43a, 43b intersects with the width direction of the size press rolls 41a, 41b (i.e., the direction of the rotation axis or generatrix of the size press rolls 41a, 41b) at an angle of less than 5 degrees. The intersection angle is preferably less than 4 degrees, more preferably less than 3 degrees, even more preferably less than 2 degrees, even more preferably less than 1 degree, and particularly preferably 0 degrees. In other words, it is particularly preferable that the longitudinal direction of the spray pattern is parallel to the width direction of the size press rolls 41a, 41b.

[0096] 7, the spray pattern of the liquid sprayed from the shower devices 43a, 43b does not intersect with the width direction of the size press rolls 41a, 41b at a large angle, so even if the surfaces of the size press rolls 41a, 41b are curved, the difference in spray amount and spray pressure between the center and edges of the spray pattern can be reduced. Therefore, spray unevenness in the width direction of the size press rolls 41a, 41b can be reduced, enabling more uniform spraying of the liquid onto the surfaces of the size press rolls 41a, 41b.

[0097] In the embodiment shown in Figure 7, uneven spraying of liquid onto the surfaces of the size press rolls 41a and 41b can be suppressed, and the liquid can be sprayed more uniformly, thereby making the wear on the surfaces of the size press rolls 41a and 41b due to the spraying of liquid more uniform.

[0098] Although the embodiment shown in Fig. 7 is a horizontal size press, the size press may be either a vertical or inclined type, or may be a gate roll type.

[0099] 7, liquid is sprayed onto the surfaces of size press rolls 41a and 41b, but liquid may also be sprayed onto rolls other than size press rolls in a paper machine. Examples of rolls other than size press rolls in a paper machine include paper transport rolls, wire rolls, press rolls, and calender rolls. In this case, too, spraying liquid can make the wear on the roll surfaces more uniform. [Industrial Applicability]

[0100] In the sheet manufacturing method of the present invention, the liquid supplied to the surface of the sheet can be distributed more uniformly on the surface, and therefore the surface properties of the sheet obtained from the liquid also become more uniform.

[0101] Furthermore, in the sheet manufacturing method of the present invention, the wear on the surface of a running body such as a roll used in manufacturing a sheet of paper or the like is more uniform, which enables, for example, the sheet manufacturing equipment to be used for a longer period of time. Furthermore, since the wear on the surface of the running body is more uniform, the shape of the surface of the sheet that comes into contact with the running body is also more uniform.

[0102] In any case, the sheet manufacturing method of the present invention can be suitably used for manufacturing sheets such as paper. [Explanation of symbols]

[0103] 1 Wire Part 2 Press Section 3 Dryer section 31 Dryer Roll 32 shower equipment 321, 322, 323 Shower unit 321a, 322a, 323a bifurcated pipe 321b, 321c, 322b, 322c, 323b, 323c Flat nozzle 41a, 41b Size press roll 42 Reservoir 43a, 43b shower equipment N nozzle SP injection pattern C center E end WP wet paper P paper

Claims

1. A method for manufacturing a sheet, comprising a step of spraying a liquid onto a surface of a sheet or a traveling body that comes into contact with the sheet, The liquid is sprayed in a fan shape, The sheet manufacturing method, wherein the longitudinal direction of the liquid spray pattern intersects with the width direction of the sheet or the traveling body at an angle of less than 5 degrees.

2. The manufacturing method according to claim 1 , wherein the longitudinal direction of the liquid spray pattern is parallel to the width direction of the sheet or the traveling body.

3. The manufacturing method according to claim 1, wherein the fan-shaped injection angle is 50 to 120 degrees.

4. The manufacturing method according to claim 1 , wherein the liquid is sprayed in a plurality of sectors, and the sectors partially overlap each other.

5. The method of claim 1 , wherein the spraying is performed by a fixed nozzle.

6. The manufacturing method according to claim 5, wherein the fixed nozzle is provided at the end of a bifurcated pipe.

7. The manufacturing method according to claim 5 , wherein the fixed nozzle is a flat nozzle.

8. The method of claim 1 , wherein the liquid comprises water.

9. The method of claim 1 wherein the sheet is paper.

10. The manufacturing method according to claim 1 , wherein the traveling body is a roll.

11. The method of claim 10, wherein the roll is a dryer roll.

12. The method of claim 10, wherein the roll is a size press roll.

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