JP2017193786A - Manufacturing method of pattern paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a pattern paper capable of manufacturing the patter paper with a pattern in high designability at good productivity easily.SOLUTION: There is a manufacturing method of pattern paper where an aggregate of microfibril cellulose, a powder and a paper strengthening agent is distributed with a dot-shaped and forms a pattern, having a wet paper forming process of storing a raw material slurry 4 containing the microfibril cellulose, the powder, the paper strengthening agent and a hydrophilic fiber in a tank 11, making paper from a solid component in the raw material slurry 4 by a paper making net 12 to form a wet paper 3 on a surface of the paper making net 12. In the wet paper forming process, the raw material slurry 4 is stored in the tank 11.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for producing a pattern paper provided with a highly designable pattern.

  Pattern paper having an excellent appearance and texture is used in a wide range of applications for the purpose of imparting product images and improving product value. In addition, as a pattern paper manufacturing method, there are various methods such as a dyeing method, various types of molding methods, a method of embedding a special shape or colored product, a method of adding agglomerates to a papermaking material and making a paper. It has been known.

  For example, in Patent Document 1, as a method for producing a pattern paper having a speckled pattern on a paper surface, the liquid colored resin particles are suspended or dispersed in a slurry containing a fiber raw material such as wood pulp. A method for wet papermaking is described. The liquid colored resin particles are composed of droplets containing an emulsion polymer and a colorant, and the surface layer portion of the droplets is constituted by a gelled product. According to Patent Document 1, the liquid colored resin particles When wet-making paper containing a slurry, liquid colored resin particles are deformed into a flat shape on the surface of the paper, and a speckled pattern excellent in design is formed without impairing the smoothness of the paper surface.

  Patent Document 2 relates to a pattern paper obtained by paper making a cloud paper, which is a kind of pattern paper, that is, a mixture of a base material composed of cellulose fibers or the like and agglomerated fibers such as rayon fibers. In addition to wet papermaking, rayon flocs are produced using rayon fibers, cationic flocculants, and anionic flocculants that have a specific range of fineness and fiber length, in addition to wet papermaking. In addition, there is described a method of wet papermaking by adding the rayon flock to a base slurry.

JP-A-4-308299 JP 2007-9374 A

  The pattern paper manufacturing methods described in Patent Documents 1 and 2 are all processes for manufacturing additives such as liquid colored resin particles and rayon flock in a separate process from the series of wet papermaking processes. There is a disadvantage in terms of manufacturing costs.

  This invention makes it a subject to provide the manufacturing method of the pattern paper which can manufacture the pattern paper to which the pattern with high designability was attached | subjected efficiently and simply.

  The present invention relates to a method for producing a pattern paper in which an aggregate of microfibril cellulose, powder and paper strength enhancer is distributed in the form of dots to form a pattern, and the microfibril cellulose, powder, paper A raw paper slurry containing a force enhancer and a hydrophilic fiber is stored in a tank, and a wet paper web forming step is performed in which a solid content in the raw material slurry is made up by a paper making net to form a wet paper on the surface of the paper making net. In the wet paper forming step, the raw material slurry is retained in the tank.

  Further, the present invention is a method for producing a pattern paper in which an aggregate of microfibril cellulose, powder and paper strength enhancer is distributed in the form of dots to form a pattern, the microfibril cellulose, powder, A wet paper forming step of storing a raw material slurry containing a paper strength enhancer and a hydrophilic fiber in a tank and forming a wet paper on the surface of the paper making net by making up solid content in the raw material slurry with a paper making net. The waste slurry that is the raw material slurry that has passed through the papermaking net in the wet paper forming step is discharged out of the tank, and a flocculant having a charge opposite to the drain slurry is added to the drain slurry. In this method, a flocculant-added slurry is obtained, and the flocculant-added slurry is introduced into the tank together with the raw material slurry and used for forming the wet paper.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the pattern paper which can manufacture the pattern paper with which the pattern with high designability was attached efficiently and simply is provided. The pattern paper of the present invention can be suitably used for, for example, fancy paper, wrapping paper, shoji paper, oil collecting paper, kitchen paper, tissue paper, sanitary carrier carrier tissue, etc. by taking advantage of its high design.

FIG. 1 is a schematic plan view of a pattern paper manufactured by the manufacturing method of the present invention. FIG. 2 is a schematic view of an embodiment of a wet paper web forming step in the pattern paper manufacturing method of the present invention. FIG. 3 is a schematic diagram (corresponding to FIG. 2) of the wet paper web forming step in the method for producing pattern paper outside the scope of the present invention.

  The pattern paper produced by the production method of the present invention is a paper in which aggregates of microfibril cellulose, powder, and paper strength enhancing agent are distributed in a dotted pattern to form a pattern. FIG. 1 shows an example of such a pattern paper. The pattern paper 1 shown in FIG. 1 is a paper having a single layer structure, and a large number of aggregates 2 are distributed in the form of dots on the entire paper surface. The aggregate 2 usually has a color (for example, black) different from the original color (usually white) of the pattern paper. In the pattern paper 1, a large number of aggregates 2 are dispersed not only in the surface direction of the pattern paper 1 but also in the thickness direction. Therefore, when the pattern paper 1 is visually observed, the color of the large number of aggregates 2 is not uniform, and a difference in density is observed between the aggregates 2, which can cause a three-dimensional visual effect with a sense of depth.

  FIG. 2 shows a part of a wet paper machine 10 which is an example of a manufacturing apparatus used for carrying out the pattern paper manufacturing method of the present invention. The wet paper machine 10 is a single-layer type circular paper machine provided with one circular net 12 as a paper net. A part of the wet paper machine 10 shown in FIG. It is a forming part. In addition to this forming part, the wet paper machine 10 dries a raw material slurry adjustment part (not shown) for preparing a raw material slurry (paper material) 4 used in the forming part and a wet paper 3 formed by the forming part. A dry part (not shown) which is a pattern paper which is a manufacturing object, and a winder part (not shown) which winds the dried continuous belt-like pattern paper in a roll shape. The basic configuration of the wet paper machine 10 is the same as that of a known wet paper machine.

  The raw material slurry adjustment part adds an apparatus such as a sizing agent, a pigment, a paper strength enhancer, a bleaching agent, and a flocculant to the fiber raw material that has been beaten and beaten (not shown). It is provided with an adding device (not shown), and is configured to prepare a stock made of a raw material having a predetermined concentration according to the characteristics of the pattern paper that is the object of manufacture. In addition, the dry part usually includes a pressurizing means such as a press roll for squeezing and dewatering the wet paper, and a heating means such as a Yankee dryer (rotary cylinder type paper machine dryer) for heating and drying the squeezed and dehydrated wet paper. doing.

  As shown in FIG. 2, the forming part of the wet paper machine 10 includes a tank 11 for storing the raw slurry 4 and an outer peripheral part formed of a mesh paper machine 12 and receives power from a motor (not shown) such as a motor. A cylindrical circular mesh suction cylinder 13 that rotates around the central axis in the direction of arrow R1 and a circular mesh suction cylinder 13 that is disposed opposite to the circular mesh suction cylinder 13 and receives power from a motor (not shown) such as a motor to rotate around the central axis in the direction of arrow R2. A cylindrical couch roll 14 that rotates in a straight line, and an endless felt 15 that travels between the circular net suction cylinder 13 and the couch roll 14.

  The tank 11 is provided with a raw material slurry supply line 20. The raw material slurry supply line 20 includes a pipe connecting the raw material slurry adjustment part and the tank 11, and the raw material slurry 4 prepared by the raw material slurry adjustment part flows through the raw material slurry supply line 20. And it supplies in the tank 11 from the raw material slurry supply port 21 provided in the tank 11. FIG.

  The papermaking net 12 is a cylindrical body formed by weaving a metal wire or a synthetic resin wire into a cylindrical shape. The circular net suction cylinder 13 is connected to a suction pump (not shown). By driving the vacuum pump to make the internal space of the circular net suction cylinder 13 negative pressure, the raw slurry 4 existing outside the papermaking net 12 is removed. A suction force for suction inside the circular net suction cylinder 13 is developed.

  Further, at the end of the circular mesh suction cylinder 13 in the rotation axis direction, the raw material slurry 4 that flows into the circular mesh suction cylinder 13 beyond the papermaking mesh 12, that is, the drainage slurry 5 (so-called white water) is external to the tank 11. A slurry discharge port 22 is provided for discharging to the surface. The slurry discharge port 22 is connected to a pipe constituting a slurry recovery line 23 attached to the tank 11, and the other end of the slurry recovery line 23 is connected to the raw material slurry supply line 20. The discharged waste slurry 5 flows through the slurry recovery line 23 and the raw material slurry supply line 20 in order and merges with the raw material slurry 4 flowing through the raw material slurry supply line 20, and then the tank 11 through the raw material slurry supply port 21. And is reused for forming the wet paper web 3. Further, a slurry disposal line 25 is connected to the middle of the slurry collection line 23 via a valve 24. By switching the valve 24, the drainage slurry 5 discharged from the slurry discharge port 22 is changed to the slurry collection line 23. It is possible to select whether to return to the tank 11 for reuse or to use the slurry disposal line 25 for disposal.

  In the method for producing a patterned paper of the present invention, a raw material slurry containing hydrophilic fibers such as wood pulp is stored in a tank, and the solid content in the raw material slurry is made up by a paper making net to wet the surface of the paper making net. It has a wet paper forming process for forming paper. More specifically, as shown in FIG. 2, in a state in which a part of the circular net suction cylinder 13 is immersed in the raw material slurry 4 in the tank 11, the papermaking net 12 as the outer peripheral portion rotates in the direction R1. However, when suction from the inside of the circular net suction cylinder 13 is performed, the raw material slurry 4 flows along the papermaking net 12 while passing through the papermaking net 12 and flows into the circular net suction cylinder 13. During the inflow, the solid content in the raw slurry 4 is made up by the papermaking net 12, and the wet paper 3 is continuously formed on the outer surface of the papermaking net 12 as the papermaking net 12 rotates. The continuous belt-like wet paper 3 formed in this way is transferred from the papermaking net 12 to the endless felt 15 at the closest position between the papermaking net 12 and the couch roll 14, and is conveyed to the dry part together with the endless felt 15 to be dried. It is attached to. In the state where the papermaking net 12 is rotated, the liquid level L1 inside the papermaking net 12 is lower than the liquid level L2 outside the papermaking net 12 as shown in FIG.

  As one of the main characteristics of the pattern paper manufacturing method of the present invention, a specific raw material slurry containing microfibril cellulose, powder, paper strength enhancer, and hydrophilic fiber is used in the wet paper sheet forming step. The raw material slurry is retained in the tank.

  FIG. 3 shows a wet paper web forming process in a forming part of a wet paper machine 10Z which is a conventional single-layer type circular paper machine. Regarding the wet paper machine 10Z, components different from those of the wet paper machine 10 shown in FIG. 2 will be mainly described, and the same components will be denoted by the same reference numerals and description thereof will be omitted. In the forming part of the conventional wet paper machine 10Z, while the raw material slurry 4 is continuously supplied from the raw material slurry supply port 21 into the tank 11, the raw material slurry 4 exceeding the predetermined water level in the tank 11 is supplied. By discharging from the overflow outlet 26 provided in the upper part of the tank 11, the water level (liquid level L2) of the raw material slurry 4 outside the papermaking net 12 in the tank 11 is kept constant. In addition, by overflowing the raw slurry 4, the thickness and texture of the wet paper 3 formed on the papermaking net 12 are maintained constant. The overflow discharge port 26 is connected to a pipe constituting the slurry recovery line 23, and the overflowed raw material slurry 4 is supplied again into the tank 11 and reused to form the wet paper 3. Yes.

  As described above, when the raw material slurry 4 is supplied from the raw material slurry supply port 21 into the tank 11 and the raw material slurry 4 is overflowed from the upper part of the tank 11 and discharged from the overflow discharge port 26 to the outside of the tank 11. The raw material slurry 4 does not stay in the tank 11, but flows in the direction indicated by the arrow F2, that is, in the direction from the raw material slurry supply port 21 to the overflow discharge port 26. The present inventor initially performed wet papermaking using a raw material slurry containing microfibril cellulose, powder and a paper strength enhancer in a system in which the raw material slurry does not stay in the tank as shown in FIG. In the paper obtained in this way, there was almost no aggregate of microfibril cellulose and powder, and it was impossible to produce a pattern paper having such an aggregate as a pattern.

  On the other hand, the inventor adjusts the liquid level L2 of the raw slurry 4 in the tank 11 to such a height that overflow from the upper part of the tank 11 does not occur as in the wet paper machine 10 shown in FIG. In the state where the raw material slurry 4 is not discharged from the overflow outlet 26 and stays in the tank 11, the raw material slurry 4 is a wet papermaking using a material containing microfibril cellulose, powder and a paper strength enhancer. As a result, aggregates of microfibril cellulose, powder, and paper strength enhancer were formed in the form of dots in the paper thus obtained, and a pattern with high designability was formed. Thus, by retaining the raw slurry in the tank during the wet paper forming step, the three components of microfibril cellulose, powder, and paper strength enhancer are locally present in high density in the tank. As a result, the number of times of contact between these three components is greatly increased as compared with the case where the raw slurry is allowed to overflow without staying in the tank, so that aggregation of these three components is promoted, As a result, it is presumed that a pattern made of aggregates was formed in a dotted pattern on the paper. In particular, microfibril cellulose has a small specific gravity compared to the liquid medium constituting the raw slurry such as water, and therefore has a strong tendency to be unevenly distributed near the liquid surface of the raw slurry. Therefore, when the raw slurry is retained in the tank, The microfibril cellulose contained in the raw slurry, for example, as shown by the arrow F1 in FIG. It is presumed that the retention of the water greatly contributes to the formation of aggregates. In other words, if the raw slurry is overflowed from the upper part of the tank during the wet paper forming process, the microfibril cellulose is less likely to stay, and thus the aggregation of the microfibril cellulose, the powder, and the paper strength enhancer It is presumed that it will be easily inhibited. The liquid level L2 is adjusted by appropriately adjusting the supply amount of the raw slurry 4 from the raw slurry supply port 21 and / or the discharge amount of the drain slurry 5 (white water) from the slurry discharge port 22. Can do.

  From the above facts, the present inventor, when forming a wet paper according to a conventional method using a wet paper machine, to retain the specific raw material slurry in the tank, specifically, for example, the specific raw material slurry It is important to prevent overflow from the tank in order to obtain a highly designable pattern paper in which agglomerates of microfibril cellulose, powder and paper strength enhancer are distributed in the form of dots. As a result, the inventors have arrived at the present invention. As described above, the pattern paper manufacturing method of the present invention uses microfibril cellulose, powder, paper strength enhancer, and hydrophilic fiber, which are conventionally used as a paper material, as raw material slurry, and a wet paper sheet forming step. Produce highly-designed pattern paper with a very simple configuration that only retains the raw material slurry in the tank during the wet paper forming process by prohibiting overflow of the raw material slurry from the top of the tank during operation Compared with the manufacturing method which requires the process of preparing the material which forms a pattern separately like the manufacturing method of the pattern paper of patent document 1 and 2, it is easy to manufacture and manufacturing cost This is advantageous.

  In addition, the present inventor can efficiently and simply manufacture a pattern paper with a pattern having a high designability by a method other than the above-described “method of retaining the raw slurry in the tank in the wet paper forming process”. I found out that Another useful method is that “a waste slurry that is a raw material slurry that has passed through the papermaking net in the wet paper forming process is discharged out of the tank, and a flocculant having a charge opposite to that of the drain slurry is added to the drain slurry. And adding the flocculant-added slurry into the tank together with the raw slurry and using it for forming wet paper (hereinafter also referred to as flocculant-adding method). The present invention also includes a method for producing a pattern paper using this coagulant addition method.

  For example, when pattern paper is manufactured using the wet paper machine 10 shown in FIG. 2, in the wet paper forming process, the drainage slurry 5 (raw material slurry 4 that has passed through the papermaking network 12), which is so-called white water, The slurry is discharged from the outlet 22 to the outside of the tank 11 and supplied into the tank 11 through the slurry recovery line 23 and the raw material slurry supply line 20 and used for forming the wet paper 3. For example, the slurry recovery line 23 is circulated. The flocculant addition method can be carried out by adding a flocculant having a charge opposite to that of the wastewater slurry 5 to the wastewater slurry 5. As a result, a flocculant-added slurry in which an aggregate of microfibril cellulose, powder, and paper strength enhancer is formed in the drain slurry 5 is obtained, and the flocculant-added slurry flows through the raw material slurry supply line 20. Since it is combined with the raw material slurry 4 and supplied into the tank 11 to be used for forming the wet paper 3, a pattern paper such as the pattern paper 1 shown in FIG. 1 is obtained. What is necessary is just to adjust suitably the addition amount of a flocculant in the range in which the aggregate of a suitable magnitude | size can form according to the density | concentration of the microfibril cellulose contained in the waste_water | drain slurry 5, etc. FIG.

  Examples of the cationic flocculant usable in the flocculant addition method include cationized starch, cationized carboxymethylcellulose, and cationic polyacrylamide.

  Examples of the anionic flocculant usable in the flocculant addition method include sodium polyacrylate, polyacrylamide-acrylic acid copolymer salt, anionic polyacrylamide and the like.

  The cationic flocculant and the anionic flocculant can adjust the cohesive force depending on the degree of neutralization, the molecular weight, and the addition amount of the functional group, and can be appropriately selected as necessary.

  Hereinafter, the slurry used in the present invention will be described. The raw material slurry used in the present invention contains microfibril cellulose (MFC), powder, paper strength enhancer and hydrophilic fiber as slurry raw materials, and usually uses water as a liquid medium. In addition, you may make the raw material slurry used by this invention contain the various additives normally used for wet papermaking other than these in the range which does not deviate from the meaning of this invention as needed.

  Microfibril cellulose is microfibrillated cellulose fiber. Microfibrillation here refers to the state in which cellulose fibers are torn to their constituent microfibrils, or the microfibrils in cellulose fibers appear on the fiber surface by friction and fluff. Specifically, it means that the cellulose fiber is subdivided to a thickness of about 0.01 to 1 μm by applying an external force such as a strong mechanical shearing force to the cellulose fiber.

  However, the microfibril cellulose used as the slurry raw material may contain cellulose fibers having a thickness exceeding 1 μm. Such incorporation of thick microfibril cellulose into the slurry raw material is usually unavoidably inadvertently caused by insufficient or no microfibrillation in the process of microfibrillation of cellulose fibers. This can occur by mixing into the raw material. The proportion of the mass of the cellulose fibers having a thickness exceeding 1 μm in the entire mass of the microfibril cellulose used as the slurry raw material is preferably 20% by mass or less.

  The type of microfibril cellulose used as the slurry raw material is not particularly limited, and it may be derived from a plant such as a tree, a microorganism such as a bacterium or a sea squirt, or an animal.

  The content of microfibril cellulose in the raw material slurry is preferably 0.01% by mass or more, more preferably 0.05% by mass with respect to the total mass of the raw material slurry, from the viewpoint of imparting a highly designable pattern to the pattern paper. % Or more, and preferably 10% by mass or less, more preferably 5% by mass or less. If the content of microfibril cellulose in the raw slurry is too small, the formation of aggregates may be insufficient and the design of the pattern paper may be reduced. If the content of microfibril cellulose is too large, the aggregates Since the amount is too large, the strength of the paper may be significantly reduced, or the paper surface may become rough.

  The powder used as the slurry raw material, together with microfibril cellulose, constitutes the pattern in the pattern paper that is the production object of the present invention. From the viewpoint of enhancing the visibility of the pattern, the color different from the original color of the pattern paper Those having the following are preferred. Since the original color of the pattern paper is white or a similar color if the pattern paper is mainly composed of normal pulp fibers, the powder preferably has a color different from that of the white system. Examples of the powder used as the slurry raw material include activated carbon such as coconut shell charcoal, charcoal powder, calendar bituminous coal, peat, lignite, etc .; dyes, pigments; organic or inorganic fine particles colored with dyes or pigments. These can be used alone or in combination of two or more.

  The content of the powder in the raw material slurry is preferably 0.1% by mass or more, more preferably 0.5% by mass, based on the total mass of the raw material slurry, from the viewpoint of imparting a pattern with high designability to the pattern paper. Above and preferably 30% by mass or less, more preferably 10% by mass or less. If the content of the powder in the raw material slurry is too small, the formation of aggregates may be insufficient and the design of the pattern paper may be lowered. If the content of powder is too large, the powder in the aggregates The body is not fixed enough and may fall off the paper due to friction.

  The paper strength enhancer used as a slurry raw material is not only for the purpose of enhancing paper strength, but also for the purpose of forming a pattern in the pattern paper which is the production object of the present invention (promoting aggregation) together with microfibril cellulose and powder. It is what is used. As the paper strength enhancer used as the slurry raw material, those usually used in wet papermaking can be used without particular limitation, for example, polyamidoamine / epichlorohydrin resin, polyvinyl alcohol resin, polyacrylamide, starch, Cationic paper strength enhancers such as glyoxal-modified polyamidoamine and epichlorohydrin resins and their salts; anionic polyacrylamide, polyacrylamide-acrylic acid copolymer, polyacrylic acid, polyacrylamide partial hydrolysate, polyacrylamide Examples include anionic paper strength enhancers such as 2-acrylamido-2-methylpropanesulfonic acid copolymer, carboxymethylcellulose, and salts thereof, and these can be used alone or in combination of two or more. . In particular, from the viewpoint of promoting the aggregation effect when the microfibril cellulose and the powder come into contact with each other, it is preferable to use two types of paper strength enhancers, cationic and anionic.

  The content of the paper strength enhancer in the raw material slurry (when two or more types are used in combination, the total content thereof) is preferably 0.3% by mass or more, more preferably 0.8%, based on the total mass of the raw material slurry. 5% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less. If the content of the paper strength enhancer in the raw slurry is too small, sufficient paper strength cannot be obtained, the formation of aggregates containing microfibril cellulose and powder becomes insufficient, and the pattern on the pattern paper is reduced. If the content of the paper strength enhancer is too large, there is a risk of paper formation failure due to paper sticking to a paper carrying blanket or a dryer.

  The hydrophilic fiber used as the slurry raw material is the main component of the pattern paper. As the hydrophilic fiber used as the slurry raw material, those usually used in wet papermaking can be used without particular limitation. For example, softwood kraft pulp (NBKP), hardwood bleached kraft pulp (LBKP), softwood bleached sulfite Wood pulp such as pulp (NBSP) and thermomechanical pulp (TMP); bast fibers such as straw, cocoon and husk; non-wood pulp such as straw, bamboo, kenaf and hemp; regenerated cellulose such as rayon, cupra, tencel and lyocell Fiber: Semi-synthetic cellulose fibers such as acetate can be used, and one of these can be used alone or in combination of two or more. Further, the beating degree of the hydrophilic fiber is not particularly limited, and may be appropriately adjusted according to the use of the pattern paper.

  The content of the hydrophilic fiber in the raw slurry is from the viewpoint of allowing a certain amount of components related to pattern formation such as microfibril cellulose and powder to be imparted to the pattern paper with practically sufficient paper strength. Is preferably 80% by mass or more, more preferably 90% by mass or more, and preferably 99% by mass or less, more preferably 95% by mass or less.

  As a preferred method for preparing the raw slurry, a method of adding a cationic paper strength enhancer and an anionic paper strength enhancer in this order to a slurry precursor containing microfibril cellulose, powder and hydrophilic fibers can be mentioned. The point of this raw material slurry preparation method is that the addition order of the paper strength enhancer is the order of the cationic strength enhancer and the anionic strength enhancer. According to such a method, first, the cationic paper strength enhancer is attached to the microfibril cellulose, so that the microfibril cellulose is charged to the cation, and then the anionic paper is charged to the microfibril cellulose charged to the cation. By attaching the force enhancer, a plurality of cation-charged microfibril celluloses are attracted to each other via the anionic paper force enhancer, so the number of contact between each component to form an aggregate The effect of increasing is produced.

DESCRIPTION OF SYMBOLS 1 Pattern paper 2 Aggregate 3 Wet paper 4 Raw material slurry 5 Drainage slurry 10, 10Z Wet paper machine (forming part)
11 Tank 12 Papermaking Network 13 Circular Suction Cylinder 14 Couch Roll 15 Endless Felt 20 Raw Material Slurry Supply Line 21 Raw Material Slurry Supply Port 22 Slurry Discharge Port 23 Slurry Recovery Line 24 Valve 25 Slurry Disposal Line 26 Overflow Discharge Port

Claims (5)

A method for producing a pattern paper in which an aggregate of microfibril cellulose, a powder and a paper strength enhancer is distributed in the form of dots to form a pattern,
A raw material slurry containing microfibril cellulose, powder, paper strength enhancer and hydrophilic fiber is stored in a tank, and the solid content in the raw material slurry is made up by a paper making net and wet paper is put on the surface of the paper making net. Having a wet paper forming process to form,
A method for producing a patterned paper, wherein the raw slurry is retained in the tank in the wet paper forming step.   The method for producing a pattern paper according to claim 1, wherein the retention of the raw slurry in the tank is performed by preventing the raw slurry from overflowing from the tank.   The said paper strength enhancer is a manufacturing method of the pattern paper of Claim 1 or 2 containing two types, cationic and anionic.   The raw material slurry is prepared by adding the cationic paper strength enhancer and the anionic paper strength enhancer in this order to a raw material slurry precursor containing microfibril cellulose, powder and hydrophilic fibers. Item 4. A method for producing a patterned paper according to Item 3. A method for producing a pattern paper in which an aggregate of microfibril cellulose, a powder and a paper strength enhancer is distributed in the form of dots to form a pattern,
A raw material slurry containing microfibril cellulose, powder, paper strength enhancer and hydrophilic fiber is stored in a tank, and the solid content in the raw material slurry is made up by a paper making net and wet paper is put on the surface of the paper making net. Having a wet paper forming process to form,
The waste slurry, which is the raw material slurry that has passed through the papermaking net in the wet paper forming step, is discharged out of the tank, and a flocculant having a charge opposite to that of the drain slurry is added to the drain slurry to add a flocculant A method for producing a pattern paper, wherein a slurry is obtained, and the flocculant-added slurry is introduced into the tank together with the raw material slurry and used for forming the wet paper.

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