JP5216052B2 - Patterned paper and method for producing the same - Google Patents

Description

  The present invention relates to a pattern paper excellent in appearance and texture and a method for producing the same, and is a multilayer papermaking of two or more layers having a surface layer and a back layer, and an aggregate is mixed in at least one of the surface layer and the back layer. The present invention relates to a pattern paper for forming a useful pattern and a method for manufacturing the pattern paper.

  Pattern paper is used for the purpose of imparting a product image and improving product value as compared to conventional paper. As a method for producing a pattern paper, many methods are known, such as a method by dyeing, a method by various types of molding, a method of embedding a special shape or colored product, and a method applying a special paper making technique. Also known are pattern papers made by blending various dyed celluloses with pulp, and pattern papers that express a pattern by blending agglomerates with papermaking raw materials, which are used for wrapping paper, stationery, etc. Yes.

  In recent years, the applications of these pattern papers have further expanded, and are also used for envelopes, box stickers, postcards, and the like, and applications for processing such as offset printing, ink jet printing, and toner printing are increasing. For this reason, the needs of pattern paper are diversified, such as imparting various uses and various processing aptitudes. As a specific example, there is a pattern paper having patterns with different color tone, color and form on the front and back. In addition, there is a demand for a pattern paper having a pattern only on one of the front and back surfaces of the pattern paper for the purpose of diversifying various uses, preventing troubles in the processing process, and imparting processing suitability.

  Inkjet printing is suitable for small lot printing because it can directly print image information such as letters and various graphics created by a computer without using a printing plate. Recently, as the resolution of inkjet printers has increased, high-quality printing has become possible and has attracted attention as a printing method that can meet market demands. In recent years, with the widespread use of home inkjet printers, demand for paper compatible with inkjet printing, such as postcards and printing paper, has increased, and pattern paper for inkjet printing has been demanded.

  A method for producing a pattern paper in which agglomerates are added to the papermaking raw material as a pattern for papermaking is disclosed (for example, see Patent Document 1 or 2). Patent Document 1 proposes a method of making an agglomerate by adding an aqueous metal salt solution to a mixed solution of sodium carboxymethylcellulose and fibers, and adding this to a papermaking raw material for papermaking. Patent Document 2 proposes a method in which a cationic electrolyte or acid is added to casein or soybean protein to produce an aggregate, and this is added to a papermaking raw material for papermaking.

Japanese Patent Laid-Open No. 3-180591 JP-A-6-166998

  The method for producing a mixed paper pattern including the technique described in Patent Document 1 or 2 includes a step of forming an agglomerate, a step of transferring the agglomerate, and aggregating the agglomerate with a papermaking raw material. And a paper making process. However, when pattern paper is made in a single layer, the amount of agglomerates cannot be adjusted between the front and back of the paper, and the difference between the front and back of the pattern tends to occur. In particular, when trying to obtain a pattern paper with a thick paper thickness, the difference between the front and the back becomes significant, and a large amount of aggregates must be blended in order to obtain a constant pattern amount on the surface.

  In addition, when a pattern paper is made in a single layer, a pattern paper having a different color tone or a different pattern color tone on the front and back sides of the paper and a pattern paper having an aggregate only on one side cannot be obtained. Further, when paper is made by mixing the agglomerate with the papermaking raw material, the agglomerate is unevenly distributed on the paper surface due to the difference in weight and size between the agglomerate and the papermaking raw material, and it is difficult to obtain a uniform pattern.

  The aggregate is formed by adding a metal salt to sodium carboxymethyl cellulose, and is completed by controlling the addition of chemicals and the share of stirring so as to obtain an optimum shape. However, the formed agglomerates are particularly susceptible to breakage due to the agitation share at the time of formation, the share by the pump at the time of transfer, and the share at the time of mixing and papermaking with the papermaking raw material, and it is not possible to maintain the agglomerates of the desired size. There was a problem. As described above, even if aggregates are formed, there are various problems in forming a pattern having a desired size and obtaining a pattern paper in which the pattern is uniformly distributed.

  An object of the present invention is to obtain an aggregate having a stable shape and having strength against a share during formation of an aggregate (hereinafter referred to as an aggregate), at the time of transfer and during papermaking, and the color tone and composition of the aggregate A pattern paper that can meet various needs by adjusting the color tone, color, and form of the patterns on the front and back sides by adjusting the amount arbitrarily, and a method for producing the pattern paper that uniformly distributes aggregates on the paper surface Is to provide.

  In order to form a pattern with a desired shape on the pattern paper, the aggregate needs strength against shear. Factors that determine the shape and strength of the aggregate include the molecular weight of sodium carboxymethyl cellulose, the aggregation action There are various factors such as the order of addition of the metal salt and the liquid polymer flocculant, the shape of the fiber to be blended, the dispersion concentration, the shape of the stirrer, the number of revolutions, and the time. As a result of intensive studies, the present inventors have found that each of the above-mentioned factors in order to maintain the strength that the aggregate has an independent individual granular or film-like stable shape and can withstand mechanical shear. Of these, the most important factor was found to be the composition of the flocculant and the order of addition. Furthermore, in the process of making a paper by blending this agglomerate into a papermaking raw material, adjusting the color tone and the amount of the agglomerate as a pattern and the agglomerate as a pattern by making two or more layers of paper. Thus, it was found that a desired pattern paper can be obtained.

The pattern paper according to the present invention is a multi-layer pattern paper having two or more layers having a surface layer and a back layer, and either the surface layer or the back layer or both layers are aggregates β containing, in the aggregates beta, between aggregates α is attached by a liquid polymeric flocculants acrylic acid copolymer type, a larger aggregates, the aggregates α is sodium carboxymethylcellulose A particulate aggregate formed by aggregating one or more substances selected from the group consisting of pigments, cellulose fibers and chemical fibers by substituting sodium ions with other metal ions It is characterized by being.

  In the patterned paper according to the present invention, the aggregate α preferably further contains a dye. Aggregates of various colors can be obtained, and as a result, a pattern paper having patterns of various colors can be obtained.

  In the patterned paper according to the present invention, it is preferable that an acrylic acid copolymer type liquid polymer flocculant is attached to the surface of both or one of the aggregate α and the aggregate β. The strength with respect to the share of the aggregate can be further improved, and a pattern paper having a pattern of a desired shape can be obtained.

  In the patterned paper according to the present invention, the acrylic polymer type liquid polymer flocculant is preferably anionic polyacrylamide. The strength with respect to the share of the aggregate can be further improved, and a pattern paper having a pattern of a desired shape can be obtained.

  In the patterned paper according to the present invention, the sodium carboxymethyl cellulose preferably has an average molecular weight of 45,000 to 300,000. The strength with respect to the share of the aggregate can be further improved, and a pattern paper having a pattern of a desired shape can be obtained. Moreover, the size of the aggregate can be made suitable for pattern paper.

  In the pattern paper which concerns on this invention, it is preferable that the average fiber length of the said cellulose fiber or the said chemical fiber taken in to the said aggregate (alpha) is 140-3000 micrometers. The size and shape of the obtained aggregate can be made suitable as a pattern paper, and a pattern paper having a pattern of a desired shape can be obtained.

  The patterned paper according to the present invention preferably further includes an inkjet ink receiving layer containing amorphous synthetic silica and a water-soluble polymer on at least one surface of the patterned paper. Pattern paper corresponding to ink jet printing can be obtained.

  The method for producing a pattern paper according to the present invention is a method for producing a pattern paper having two or more layers having a surface layer and a back layer, and is selected from the group consisting of a sodium carboxymethyl cellulose aqueous solution, a pigment, a cellulose fiber, and a chemical fiber. Step 1 for mixing the one or more kinds of substances formed, Step 2 for adding an aqueous metal salt solution to the mixture obtained in Step 1, and forming an aggregate α by stirring, and the step obtained in Step 2 above Step 3 for forming an aggregate β by adding an acrylic acid copolymer type liquid polymer flocculant to a liquid containing the aggregate α, and the aggregate β obtained in the step 3 is used for the paper making for the surface layer. A step 4 for preparing a surface paper and a back layer paper by adding to one or both of the raw material and the paper for the back layer, and a step 5 for making the paper. To do.

  In the pattern paper manufacturing method according to the present invention, it is preferable that the step 5 is made by using a dry-tart type circular net paper machine. Pattern paper in which the pattern is uniformly distributed can be manufactured.

  In the pattern paper manufacturing method according to the present invention, the acrylic polymer type liquid polymer flocculant is an anionic polyacrylamide and a cationic polyacrylamide, and after adding the anionic polyacrylamide, the cationic polyacrylamide is added. It is preferred to add acrylamide. By adding in this order, a stronger aggregate can be formed, and a pattern paper having a pattern of a desired shape can be produced.

  The pattern paper manufacturing method according to the present invention preferably further includes a step 6 of providing an inkjet ink receiving layer containing amorphous synthetic silica and a water-soluble polymer on at least one surface of the pattern paper. Pattern paper corresponding to inkjet printing can be manufactured.

  The present invention obtains an aggregate having a stable shape and having strength against the share at the time of formation of the aggregate, at the time of transfer and during papermaking, and by arbitrarily adjusting the color tone and blending amount of the aggregate. It is possible to provide a pattern paper that can meet various needs by adjusting the color tone, color, and form of the pattern, and in which aggregates are uniformly distributed on the paper surface, and a method for producing the pattern paper.

It is a figure for demonstrating a multilayer papermaking bat type | formula net paper machine, (a) is an enlarged view of the circular net part which performs the last papermaking, (b) is an expansion of the X section of (a). FIG. It is a figure for demonstrating a multilayer papermaking dry-tart type | formula net | network paper machine, and is an enlarged view of the net | network part which performs the last papermaking.

  Next, the present invention will be described in detail with reference to embodiments, but the present invention is not construed as being limited to these descriptions. As long as the effect of the present invention is exhibited, the embodiment may be variously modified.

  The method for producing a patterned paper according to the present embodiment is a method for producing a pattern paper having two or more layers having a surface layer and a back layer, and is selected from a group consisting of a sodium carboxymethyl cellulose aqueous solution, a pigment, a cellulose fiber, and a chemical fiber. Step 1 for mixing one or more selected substances, Step 2 for adding an aqueous metal salt solution to the mixture obtained in Step 1, and forming an aggregate α by stirring, and Aggregate obtained in Step 2 Step 3 in which an acrylic acid copolymer type liquid polymer flocculant is added to a liquid containing α to form an aggregate β, and the aggregate β obtained in Step 3 is used as a papermaking raw material or back layer for the surface layer Step 4 for preparing a surface paper and a back layer paper by adding to one or both of the papermaking raw materials for use, and a process 5 for papermaking. Here, Step 1 to Step 3 are aggregate production steps, and Step 4 and Step 5 are pattern paper production steps.

  In step 1, it is preferable that the aqueous sodium carboxymethyl cellulose solution and the selected one or more substances are mixed well with stirring. In step 2, an aggregate α may be formed by adding the aqueous metal salt solution to the mixture obtained in step 1 and then stirring. However, the aqueous solution of metal salt is added to the mixture while stirring to coagulate. It is more preferable to form the aggregate α in that a uniform aggregate α can be obtained. In Step 3, the liquid polymer flocculant of the acrylic acid copolymer type may be added to the liquid (aggregate α slurry) containing the aggregate α formed in Step 2 and then stirred. It is more preferable to add an acrylic acid copolymer type liquid polymer flocculant while stirring the α slurry in that a uniform aggregate β can be obtained.

  It is preferable that the density | concentration of the sodium carboxymethylcellulose aqueous solution used at the process 1 is 0.05-4.00 mass%. More preferably, it is 0.10 to 3.00 mass%. If it is less than 0.05% by mass, the strength of the aggregate may be weakened. If it exceeds 4.00% by mass, the fluidity of the aqueous solution may decrease, and a uniform aggregate may not be obtained.

  It is preferable that the density | concentration of the metal salt aqueous solution used at the process 2 is 1-60 mass%. More preferably, it is 3-50 mass%. If it is less than 1% by mass, the cohesive force is insufficient and it may be difficult to form the particulate aggregate α. If it exceeds 60% by mass, flocs may be formed with the entire papermaking raw material, and the particulate aggregate α may not be formed. In the present embodiment, the concentration of the metal salt aqueous solution used in step 2 is not limited.

  The concentration of the acrylic acid copolymer type liquid polymer flocculant used in Step 3 is preferably 0.01 to 2.00% by mass. More preferably, it is 0.03-1.00 mass%. If it is less than 0.01% by mass, the strength of the aggregate β may become weak. When it exceeds 2.00 mass%, the fluidity | liquidity of aqueous solution will fall and it may become impossible to obtain the uniform aggregate (beta).

  The acrylic copolymer type liquid polymer flocculant added in step 3 is preferably an anionic polyacrylamide. Aggregates β having higher strength against shear can be formed.

  Furthermore, in order to form a stronger aggregate β (hereinafter sometimes referred to as aggregate β ′), a liquid polymer flocculant of an acrylic acid copolymer type is used for anionic polyacrylamide and cationic polyacrylamide. It is acrylamide, and it is preferable to add cationic polyacrylamide after adding anionic polyacrylamide.

  Factors that determine the shape and strength of the aggregate β include the molecular weight of sodium carboxymethyl cellulose, the order of addition of the metal salt having an aggregating action and the liquid polymer flocculant, the shape of the fiber to be blended, the dispersion concentration, the shape of the stirring bar, There are various factors such as rotation speed and time. As a result of intensive studies, the inventors have found that, among the above factors, the aggregates have independent individual granular or film-like stable shapes, and the strength that can withstand the mechanical share is maintained. The composition of the aggregates and the order of addition, the molecular weight of sodium carboxymethyl cellulose, and the shape of the fiber were found. The most important factors are the composition of the flocculant and the order of addition.

  In step 2, when an aqueous metal salt solution is added to sodium carboxymethylcellulose, sodium ions and metal ions are substituted to form individual aggregates α having cationic properties. In Step 3, by adding anionic polyacrylamide to the aggregate α, the aggregates α are aggregated by the action of charge neutralization and adsorption crosslinking, and the aggregate β has a higher strength against the share. Thereafter, by adding cationic polyacrylamide, it is possible to form an aggregate β ′ in which stronger individual grains are independent by ionic bonding. The aggregate α slurry formed in step 2 precipitates when left standing, but appears to be cloudy when stirred. In step 3, when an anionic polyacrylamide is added to the aggregate α, the slurry of the aggregate β becomes transparent even during stirring. From the above state, it is presumed that each aggregate α has a relatively small particle diameter, and the aggregate β has a larger particle diameter than the aggregate α. The size of the aggregate α and aggregate β depends on the manufacturing conditions of the various aggregates such as the molecular weight of sodium carboxymethyl cellulose, the shape / size / type of fiber to be blended, the dispersion concentration, the shape of the stirrer, the rotational speed, and the time. Although different, for example, the average diameter of the aggregate α is 0.5 to 3.0 mm, and the average diameter of the aggregate β is 1.0 to 5.0 mm.

  In the manufacturing process of the aggregate, the shape of the stirring bar is, for example, a propeller type, a turbine type, an anchor type, a saddle type, a planet type, a screw type, a ribbon type, an intensive type, or a helical ribbon type. The diameter and shape of the stirring bar of the stirring device are not particularly limited as long as the entire slurry can be stirred uniformly. The number of rotations is preferably 100 to 800 rpm, and more preferably 200 to 600 rpm. The stirring time is not particularly limited as long as the whole slurry is uniformly stirred and aggregates α or aggregates β are formed.

  Aggregate β is formed by aggregation of sodium carboxymethyl cellulose by substitution of sodium ions with other metal ions, and one or more kinds selected from the group consisting of pigments, cellulose fibers, and chemical fibers. A particulate agglomerate containing a substance is defined as an agglomerate α, and the agglomerates α adhere to each other with an acrylic acid copolymer type liquid polymer flocculant to form a larger agglomerate.

  Aggregates α are those in which sodium ions and metal ions are substituted and aggregated and insolubilized by adding a metal salt to sodium carboxymethylcellulose. For this reason, when an acrylic acid copolymer type liquid polymer flocculant is first added to sodium carboxymethylcellulose without adding an aqueous metal salt solution, the entire liquid aggregates into a gel and thickens. Therefore, the particulate aggregate α cannot be obtained. In addition, if only the aqueous solution of metal salt is added and then the liquid polymer flocculant of acrylic acid copolymer type is not added, particulate aggregate α can be obtained, but it is very brittle. It is destroyed by the shear generated in the process of stirring, transferring and paper making.

  The average molecular weight of the anionic and cationic acrylic acid copolymer type liquid polymer flocculant to be added is not particularly limited in the present embodiment, but the average molecular weight is 300,000 to 15 million. This is desirable from the viewpoint of improving the strength with respect to the share of the aggregate β and the viscosity when producing the aggregate β. The average molecular weight of the anionic and cationic acrylic acid copolymer type liquid polymer flocculant is more preferably 1 million to 13 million, and particularly preferably 3 million to 12 million.

  Sodium carboxymethyl cellulose is not limited to an average molecular weight in this embodiment, but sodium carboxycellulose having a certain average molecular weight is required to obtain an aggregate β having a strength suitable for the share in the process and a size suitable as a pattern paper. It is effective to use. That is, in this embodiment, it is preferable that the average molecular weight of sodium carboxymethylcellulose is 45,000-300,000. More preferably, it is 50,000-290,000, Most preferably, it is 60,000-280,000. The average molecular weight of sodium carboxymethyl cellulose greatly affects the strength and shape of the aggregate β. When the average molecular weight is less than 45,000, the strength of the aggregate β is weak and may be easily broken by the share of stirring or transfer. In addition, the particles of the aggregate β are likely to be fine, and may not be suitable for the aggregate for pattern paper. On the other hand, when the average molecular weight exceeds 300,000, there is no problem as the strength of the aggregate β, but the viscosity of the aqueous sodium carboxymethyl cellulose solution becomes very high. Furthermore, when the aqueous metal salt solution is added, the aggregate α The shape becomes very large, and as a result, the aggregate β may not be suitable as an aggregate for pattern paper. In addition, since it is necessary to increase the stirring as the viscosity increases, a small aggregate α is formed around the stirrer, and a large aggregate α is formed in a portion far from the stirrer. As a result, the aggregate β The shape may be uneven.

  Cellulose fibers or chemical fibers have a role as a binder, and a large aggregate β can be obtained by adding them. In this embodiment, although it does not specifically limit to the form of a fiber, The length of a fiber influences the magnitude | size and shape of the aggregate (beta) obtained. For example, when the fiber length is short, the aggregate β is small and particles are obtained, and when the fiber length is long, the aggregate β is large and long. Therefore, in this embodiment, it is preferable that the average fiber length of the cellulose fiber or the chemical fiber is 140 to 3000 μm. More preferably, it is 160-750 micrometers, Most preferably, it is 180-300 micrometers. Generally, the upper limit of the average fiber length of softwood bleached kraft pulp (N-BKP) is about 3000 μm, and the upper limit of the average fiber length of hardwood bleached kraft pulp (L-BKP) is about 750 μm. By setting it in the above range, the size and shape of the aggregate β more suitable as a pattern paper can be formed. Furthermore, when a metal salt aqueous solution is added to an aqueous solution of sodium carboxymethylcellulose and agglomerated, cellulose fibers and chemical fibers are taken into the insolubilized sodium carboxymethylcellulose, forming a strong aggregate α. And the strength of the aggregate β can be further increased. By adding a cellulose fiber or chemical fiber having a short average fiber length of 140 to 300 μm, an aggregate α that is particularly resistant to shear can be formed, and the strength of the aggregate β relative to the shear can be further increased. On the other hand, when fibers having a large and long average fiber length exceeding 3000 μm are used, the aggregate α has a weak strength against the shear, and the strength with respect to the shear of the aggregate β may be weak. This is presumed to be because the aggregate becomes a form in which sodium carboxymethyl cellulose joins the fibers together, and is easily broken by the share in each step. If the thickness is less than 140 μm, the strength of the aggregate α is weak and tends to be minute, so the aggregate β cannot be formed into a desired shape, and a pattern paper having a pattern with a desired shape cannot be obtained. is there.

  Cellulose fibers are, for example, wood pulps such as N-BKP and L-BKP, cellulose powders such as refined powdered cellulose, and cellulose derivatives such as cellulose acetate, regenerated cellulose, carboxymethylcellulose, hydroxyethylcellulose, and cellulose nitrate. The chemical fiber is, for example, nylon, polyester, or polyolefin. In the present embodiment, it is not limited to the types of cellulose fiber and chemical fiber, but when using chemical fiber, the one added with a hydroxyl group so as to easily bind to water-soluble sodium carboxymethyl cellulose, Aggregates β having higher strength can be obtained, which is preferable.

  The pigment has a role of coloring the aggregate β or a role of imparting opacity to the aggregate β. By adding the pigment, the aggregate has various characteristics such as chromatic color and high opacity. Can be formed. Examples of the pigment include a colored pigment that imparts a chromatic color, a white pigment that imparts high opacity, and the like. The color pigment is, for example, a phthalocyanine pigment or an azo pigment. The white pigment is an inorganic pigment such as titanium oxide, synthetic silica, kaolin, clay, calcium carbonate, talc, barium sulfate, or aluminum hydroxide. Organic pigments such as plastic pigments may also be used. In the present embodiment, the type of pigment is not limited.

  In the pattern paper manufacturing method according to this embodiment, it is preferable to further contain a dye in the aqueous sodium carboxymethyl cellulose solution. Examples of the dye include polyazo dyes, thiazole monoazo dyes, organic pigment sulfonated dyes such as phthalocyanine dyes and dioxazine dyes, and basic group-containing dyes (basic direct dyes). In this embodiment, it is not limited to the kind of dye.

  Examples of the metal salt of the metal salt aqueous solution include aluminum sulfate (sulfuric acid band), aluminum chloride, aluminum acetate, aluminum hydroxide, calcium hydroxide, ferrous sulfate, ferric chloride, cupric chloride, zinc sulfate, Examples include lead acetate and barium chloride. In this embodiment, although not limited to the kind of metal salt, an aluminum salt is preferable from the viewpoint of the ability to aggregate, and aluminum sulfate is particularly preferable from the viewpoint of the aggregation power and price. As a compounding quantity of a metal salt, it is preferable that it is 50-300 mass parts with respect to 100 mass parts of sodium carboxymethylcellulose in conversion of solid content. More preferably, it is 65-250 mass parts, Especially preferably, it is 80-200 mass parts. When the blending amount of the metal salt is less than 50 parts by mass, the cohesive force is insufficient and fine aggregation occurs, but the granular aggregate α may not be formed. Moreover, when it exceeds 300 mass parts, when mix | blending with a papermaking raw material, the whole papermaking raw material will be formed and a flock may be formed and a formation may deteriorate.

  Formation of the aggregate β is carried out by insolubilizing sodium carboxymethyl cellulose with a metal salt and an acrylic acid copolymer type polymer flocculant, and taking in fibers, pigments, and the like at this time. As a result, when the compounding ratio of sodium carboxymethyl cellulose is too small, the strength of the aggregate β may be insufficient. Then, it is preferable that the compounding quantity of sodium carboxymethylcellulose is 7.50-40.0 mass parts with respect to 100 mass parts of dry mass of the whole aggregate. More preferably, it is 10.0-35.0 mass parts, More preferably, it is 12.5-30.0 mass parts. When the blending ratio of sodium carboxymethyl cellulose exceeds 40.0 parts by mass with respect to 100 parts by mass of the dry mass of the entire aggregate, the aggregate is blended with the papermaking raw material, and then the aggregate is formed by papermaking and drying in the papermaking process. In some cases, the drying shrinkage of the portion is increased, and the surface may be uneven. If it is less than 7.50 mass parts, the intensity | strength of the aggregate (beta) may become weak.

  As a compounding quantity of the cellulose fiber or chemical fiber mixed with sodium carboxymethylcellulose aqueous solution, it is preferable that it is 30.0-350 mass parts with respect to 100 mass parts of sodium carboxymethylcellulose in solid content conversion. More preferably, it is 50.0-325 mass parts, Most preferably, it is 75.0-300 mass parts. If it is less than 30.0 parts by mass, the effect of blending cellulose fibers or chemical fibers is weak. If it exceeds 350 parts by mass, the shape of the aggregate β becomes large, but the strength against shear may be weak.

  As a compounding quantity of the coloring dye or coloring pigment mix | blended with sodium carboxymethylcellulose aqueous solution, it can add suitably according to the desired color tone. The compounding quantity of a coloring dye or a coloring pigment is 1.00-10.0 mass parts with respect to 100 mass parts, for example with sodium carboxymethylcellulose. Moreover, when adding a white pigment in order to obtain the aggregate of high opacity, it is preferable that it is 10.0-300 mass parts in conversion of solid content with respect to 100 mass parts of sodium carboxymethylcellulose. More preferably, it is 25.0-200 mass parts, Especially preferably, it is 40.0-125 mass parts. If it is less than 10.0 parts by mass, the opacity may be insufficient. When it exceeds 300 mass parts, the intensity | strength with respect to the share of the aggregate (beta) may become weak. Furthermore, in the pattern paper made by blending the aggregate with the papermaking raw material, the surface strength of the pattern portion of the aggregate is weakened, and the pattern portion may be peeled off in post-processing such as a printing process. In addition, the white pigment is excessive and uneconomical.

  As the blending amount of the acrylic acid copolymer type liquid polymer flocculant blended in the aggregate α slurry, in anionic polyacrylamide, 1.00 to 100 parts by weight of sodium carboxymethyl cellulose in terms of solid content. It is preferably 15.0 parts by mass. More preferably, it is 1.50-12.5 mass parts, Most preferably, it is 2.00-10.0 mass parts. If it is less than 1.00 mass part, the intensity | strength improvement with respect to the share of the aggregate (beta) may become inadequate. When the amount exceeds 15.0 parts by mass, the viscosity of the aggregate α slurry is increased, and further, the formed aggregate β particles are further agglomerated to form a tuft, which becomes a pattern paper flocculant. It may become an unsuitable shape.

  On the other hand, in cationic polyacrylamide, it is preferable that it is 0.100-7.50 mass parts with respect to 100 mass parts of sodium carboxymethylcellulose. More preferably, it is 0.300-5.00 mass part, Most preferably, it is 0.500-3.00 mass part. Cationic polyacrylamide can obtain an effect as compared with addition even in a small amount, but if it is less than 0.100 parts by mass with respect to 100 parts by mass of sodium carboxymethyl cellulose, the effect of addition may not be obtained. is there. When the amount exceeds 5.00 parts by mass, the excess cationic polyacrylamide forms flocs with the papermaking raw material when the aggregate β is added to the papermaking raw material, and the formation becomes uneven. There is a case. Pattern paper with a non-uniform texture may cause some unevenness in various physical properties such as smoothness and air permeability, which may cause problems in post-processing such as printing. Moreover, it is preferable that the compounding mass ratio of anionic polyacrylamide and cationic polyacrylamide is 100: 2-100: 350 in conversion of solid content. More preferably, it is 100: 10-100: 150.

  In the pattern paper manufacturing method according to the present embodiment, in step 2, the pH of the mixed solution when adding the metal salt aqueous solution to the mixed solution obtained in step 1 is 3.0 to 8.0. It is preferable. More preferably, it is 3.5-7.5, Most preferably, it is 4.0-7.0. If the pH is less than 3.0, the aggregate α may be difficult to form, or the strength of the aggregate α may be weak. If the pH exceeds 8.0, the aggregate α may be difficult to form.

  Further, the pH of the aggregate α slurry when the acrylic acid copolymer type liquid polymer flocculant is added to the aggregate α slurry obtained in Step 2 is preferably 3.0 to 8.0. . More preferably, it is 3.5-7.5, Most preferably, it is 4.0-7.0. If pH is less than 3.0, the intensity | strength of the aggregate (beta) formed may become weak. When the pH exceeds 8.0, the viscosity of the aggregate α slurry is increased, and further, the formed aggregate β particles are further aggregated to form a tuft. The shape may be unsuitable as an aggregate for use.

  Next, the pattern paper manufacturing process will be described. In step 4, the aggregate β is added to both the surface layer stock material and the back layer stock material, or to either the surface layer stock material or the back layer stock material. It may be added. When the same pattern is provided on both the front layer and the back layer, the same aggregate β is blended into the papermaking raw material of each layer, and the blending amount of the aggregate β into the papermaking raw material for the surface layer and the papermaking raw material for the back layer By adjusting the blending amount of each aggregate β, the pattern amount on the front and back of the pattern paper can be made more uniform. When different patterns are provided on the surface layer and the back layer, the same aggregate β is blended into the papermaking raw material of each layer, and the blending amount of the aggregate β into the papermaking raw material for the surface layer and the aggregate to the papermaking raw material for the back layer By changing the blending amount of β, it is possible to obtain a pattern paper having different patterns on the front and back sides. Furthermore, by changing the type of the aggregate β to be blended with the paper material for the front layer and the type of the aggregate β to be blended with the paper material for the back layer, it is possible to obtain a pattern paper having different patterns on the front and back sides. Moreover, it becomes possible to provide a pattern only in either the surface layer or the back layer by blending the aggregate β only in either the paper material for the surface layer or the paper material for the back layer. Furthermore, the color tone of a pattern paper and the color tone of a pattern can be arbitrarily adjusted with a surface layer and a back layer by mix | blending a coloring agent with a papermaking raw material, and mix | blending the aggregate (beta) which has a different color tone.

  Aggregate β is preferably blended with the paper stock as a slurry. The concentration of the aggregate β slurry is preferably 0.2 to 4.0% by mass. More preferably, it is 0.5-3.0 mass%. If it is less than 0.2% by mass, the aggregate β may not be uniformly dispersed in the paper material. If it exceeds 4.0 mass%, the viscosity of the slurry becomes high, and workability may be inferior.

  In recent years, it has become important to use a lot of recycled pulp (waste paper pulp, deinked pulp) as an environmental consideration for paper products. When using waste paper pulp, it is preferable to increase the amount of waste paper pulp in the middle layer as compared with the front layer and back layer as a multi-layer papermaking of three or more layers provided with a middle layer between the surface layer and the back layer. . By configuring in this way, it is possible to obtain a pattern paper with less impurities and excellent texture and environmentally friendly. In addition, in the case of three or more layers, the aggregate β is added to at least one of the paper material for the front layer or the paper material for the back layer. The composition of the aggregate β is arbitrary. That is, the aggregate β may not be blended with the middle layer papermaking raw material, or the aggregate β may be blended with the middle layer papermaking raw material. It can be appropriately selected according to the form and texture of the pattern paper.

  In the present embodiment, the basis weight of each layer of the pattern paper does not need to be uniform, and in the case of making two layers, the surface layer and the back layer may have the same thickness, or the surface layer is thicker than the back layer. Or vice versa. In the case of making three or more layers, it is possible to make the basis weight of the intermediate layer relatively larger than the basis weight of the front layer and the basis weight of the back layer, for example. Furthermore, it is possible to make the front layer and the back layer one layer each and the intermediate layer to be two layers or more. In the present embodiment, the basis weight of each layer is not limited.

  In step 5, the paper stock of each layer prepared in step 4 is made. The present embodiment is not limited to a papermaking method as long as it is a multi-layer papermaking. However, in the pattern paper manufacturing method according to this embodiment, papermaking is preferably performed using a dry-tart type circular net paper machine. General paper machines are roughly classified into long net paper machines and circular net paper machines. In the case of multi-layer papermaking, a papermaking facility is required for each layer. Therefore, it is advantageous in terms of installation space, installation cost, and running cost, and because it has good formation, circular net paper machines are often used. ing. General circular paper machines are roughly classified into a bat type and a dry-hat type.

  FIG. 1 is a diagram for explaining a multi-layer bat-type circular net paper machine. FIG. 1 (a) is an enlarged view of a circular mesh portion where the final paper making is performed, and FIG. 1 (b) is an enlarged view of an X portion of (a). As shown in FIG. 1A, the circular net portion of the bat type circular net paper machine 10 includes a bat 11, a cylindrical cylinder 12, and a couch roll 13. The vat-type paper machine 10 sequentially forms wet sheets 15 on the wire surface of the cylindrical cylinder 12 in which the flowing stock material rotates in the vat 11, and transfers the wet sheets 15 onto the felt 16 by the couch roll 13. Until the wet sheet 15 formed in the bat 11 exits from the liquid surface 21 of the raw material bat 11 into the atmosphere and reaches the couch roll 13, as shown in FIG. The wet sheet 15 runs off 24 at the portion that has been exposed to the atmosphere, and the surface of the wet sheet 15 is washed away. This is a phenomenon peculiar to the bat type circular net paper machine, but the flow-down 24 is more likely to occur on the surface of the wet sheet 15 having a weak adhesion to the wire. When the aggregate β is added to the stock material, the wet sheet 15 Aggregates β on the surface of these particles are likely to flow down. In particular, the larger the aggregate β, the more noticeable the drop 24 is, and this is the cause of uneven distribution of the aggregate β. This phenomenon is also caused by non-uniform distribution in the width direction. This is because the arm in the cylindrical cylinder 12 has a portion that tends to flow down in the width direction and a portion that is relatively difficult to flow down, and the aggregate β may be distributed in a streak pattern on the paper surface. For this reason, in order to obtain a pattern paper having a uniform surface pattern using the base paper stock containing the aggregate β by the bat type circular net paper machine 10, the liquid level 21 of the bat 11 and the cylindrical cylinder 12 Know-how such as adjustment of the head difference from the internal liquid level 22 and adjustment of the paper making speed is required. Further, when the flow-off 24 of the aggregate β occurs, the concentration of the aggregate β with respect to the stock material in the bat 11 is increased, and the stock material overflowing the inside of the bat 11 is circulated again and recirculated. However, the aggregate β is destroyed by the share at the time of circulation and becomes small. Therefore, in order to obtain the uniformity of the pattern on the pattern paper surface, it is necessary to perform an operation in which the flow-off 24 of the aggregate β is reduced.

  In order to prevent the non-uniform distribution of the pattern paper pattern due to the flow-off 24 as described above, it is preferable to make a paper base paper blended with the aggregate β with a dry-tart type net paper machine. For example, various types of circular net formers, pressure formers for forming paper layers, suction formers, and on-tops where paper stocks are placed on top of the cylinders. There is a former. FIG. 2 is a diagram for explaining the multilayer paper-making dry-hat type circular paper machine, and is an enlarged view of the circular net portion for performing the final papermaking. 2 is a pressure former type, and includes a paper supply slit 51, a cylindrical cylinder 52, and a couch roll 53. The dry form paper machine 50 shown in FIG. The stock material supplied from the stock supply slit 51 forms a paper layer 55 along the cylindrical cylinder 52, and the paper layer 55 is copied onto the felt 56 by the couch roll 53. In this way, the dry-mat type net paper machine 50 makes the paper stock supplied by adsorbing, pressurizing or placing almost the entire amount of the supplied stock on the cylindrical cylinder 52, so that it flows down like the bat type net paper machine 10 of FIG. 24 does not occur, the aggregate β does not fall off, and a uniform pattern can be formed on the paper surface. Furthermore, compared to the vat-type circular net papermaking 10, there is little or no overflow of the papermaking raw material, so that it is possible to obtain a pattern paper with little variation in the size of the aggregate pattern over time.

  Wood pulp is most preferably used as the papermaking raw material, but other natural pulp, waste paper pulp or synthetic pulp may be appropriately used as necessary. In this embodiment, it is preferable to use natural pulp as a main component. When natural pulp is the main component, 70% or more of the absolute dry pulp contained in the papermaking raw material of each layer is preferably natural pulp. More preferably, it is 900%, and particularly preferably 100%. Natural pulp is hardwood that has been subjected to normal bleaching treatment of chlorine, hypochlorite, chlorine dioxide bleaching, alkali extraction or alkali treatment, oxidative bleaching treatment such as hydrogen peroxide, ozone bleaching, or a combination thereof as necessary. Pulp, softwood pulp or a mixed pulp thereof is preferred. Moreover, soda pulp and mechanical pulp can be used. Waste paper pulp, regardless of its raw material, deinking method, or bleaching method, must be blended to such an extent that it does not impair the strength of the base paper. Various synthetic pulps can also be used.

  The above pulp is beaten as necessary by various beating machines such as a disk type and a conical type so as to have an appropriate freeness. Freeness is an important factor that determines the physical strength of the base paper, so that the strength increases as the beating progresses. However, since freeness causes a decrease in air permeability, opacity, bulk, etc., 350 ml C.S.F. (JIS P 8121: 1995 Canadian Standard Freeness) to 700 mlC.S.F. More preferably, it is 400 mlC.S.F. or more and 570 mlC.S.F. or less. In the present embodiment, the Canadian standard freeness is not particularly limited.

  In addition to the above pulp, various papermaking chemicals such as paper strength agents, fillers, sulfuric acid bands, yield improvers, sizing agents, dyes, and fluorescent dyes can be appropriately used in the base stock. The paper strength agent is, for example, cationized starch, amphoteric starch, or polyacrylamide. Fillers include, for example, heavy calcium carbonate, light calcium carbonate, magnesium carbonate, calcium / magnesium carbonate, kaolin, calcined clay, natural silicates such as bentonite, sericite, zeolite, talc, synthetic aluminum silicate, synthetic calcium silicate, etc. These are silicic acid such as synthetic silicate, diatomaceous earth and synthetic silica, aluminum hydrate such as aluminum hydroxide and pseudoboehmite, or calcium sulfate, titanium dioxide and zinc oxide. The yield improver is, for example, colloidal silica, polyacrylamide, or polyethyleneimine. The sizing agent is, for example, alkyl ketene dimer (AKD), alkenyl succinic anhydride (ASA), neutral rosin, reinforced rosin, or saponified rosin, and can be appropriately selected depending on the pH of papermaking. The dye and the fluorescent dye are, for example, a direct dye, a basic dye, and an acid dye, and are added to adjust the hue of the paper. Moreover, it is possible to contain a bulking agent, but it must be limited to such an extent that a decrease in surface strength is not a problem. The present embodiment is not limited to the preparation method, blending, and addition method of each papermaking chemical.

  By adding a colorant different from the aggregate β to color the base paper before mixing the aggregate β and the papermaking raw material, the pattern pattern of the aggregate β can be more effectively formed. Can stand out. Further, the pattern of the pattern paper can be made to stand out by giving different colors to the aggregate β and the papermaking raw material, or changing the color density even with the same color. The colorant is, for example, a dye or fluorescent dye of the above-mentioned papermaking chemical or a color pigment. The color pigment is not particularly limited, and is, for example, a phthalocyanine pigment or an azo pigment. Although the addition amount of a coloring agent can be suitably selected according to the color tone desired, it is preferable to set it as 0.005-2.000 mass part with respect to 100 mass parts of absolutely dry pulp. More preferably, it is 0.010-1.000 mass parts.

  It is preferable that the addition amount of aggregate (beta) is 0.001-8000 mass parts in conversion of solid content with respect to 100 mass parts of dry mass of the papermaking raw material of the layer to add. More preferably, it is 0.005-6000 mass part, Most preferably, it is 0.010-4,000 mass part. In the present embodiment, the amount of aggregate β is not particularly limited. Moreover, in this embodiment, the papermaking raw material and the aggregate (beta) should just be mixed uniformly as a whole, and it is not restrict | limited to the mixing method.

The obtained pattern paper may be subjected to a surface sizing treatment for the purpose of improving surface properties such as water resistance and surface strength. The surface size liquid used in the surface sizing treatment is, for example, oxidized starch, cationized starch, hydroxyethyl etherified starch, enzyme-modified starch, or polyacrylamide resin. Surface sizing agents such as polyvinyl alcohol, carboxymethyl cellulose, methyl cellulose, and other resin polymers can also be used. It is preferable to apply this surface sizing liquid on both sides or one side by a size press in a range of 0.2 to 5.0 g / m ² per side by dry mass. More preferably, it is applied in the range of 0.5 to 3.0 g / m ² . The surface size liquid is applied by, for example, using a device that applies chemicals to a web formed on a papermaking wire in a nip between two rolls, such as a size press and a transfer roll coater. Apply liquid. In the present embodiment, the method for applying the surface sizing liquid, the type of the surface sizing liquid, and the application amount are not limited.

  Moreover, you may perform a calendar process as needed for the purpose of controlling the smoothness of a surface. Examples of the calendar include a super calendar, a machine calendar, and a soft calendar, but are not particularly limited in the present embodiment.

The pattern paper according to the present embodiment is a multi-layer pattern paper having two or more layers having a surface layer and a back layer, and either one or both of the surface layer and the back layer contains an aggregate β. To do. Then, the aggregate beta, between aggregates α is attached by a liquid polymeric flocculants acrylate copolymer type, a larger aggregates. In this aggregate α, sodium carboxymethyl cellulose has incorporated one or more substances selected from the group consisting of pigments, cellulose fibers, and chemical fibers by substituting sodium ions with other metal ions. It is a particulate aggregate formed by aggregation.

  In the patterned paper according to the present embodiment, the aggregate α preferably further contains a dye. Aggregates β of various colors can be formed, and as a result, a pattern paper having patterns of various colors can be obtained.

  In the pattern paper according to the present embodiment, it is preferable that an acrylic acid copolymer type liquid polymer flocculant is attached to the surface of both or one of the aggregate α and the aggregate β. For example, the liquid polymer flocculant is adhered to the surface of the aggregate α, and the liquid polymer flocculant is formed on the surface of the aggregate β formed by adhering the aggregate α to each other by the liquid polymer flocculant. Is a form in which the liquid α-coagulant is adhered to the surface, and the liquid α-coagulant adheres to the surface of the aggregate β. As described above, the liquid polymer flocculant adheres to the surface of both or one of the aggregate α and the aggregate β, whereby the strength against shear can be further improved. Therefore, it can be set as the pattern paper which has a pattern of a desired shape in a pattern paper.

  In the patterned paper according to the present embodiment, the acrylic polymer type liquid polymer flocculant is preferably an anionic polyacrylamide. The strength with respect to the share of the aggregate β can be further improved, and a pattern paper having a pattern with a desired shape can be obtained.

  In the patterned paper according to the present embodiment, the average molecular weight of sodium carboxymethyl cellulose is preferably 45,000 to 300,000. More preferably, it is 50,000-290,000, Most preferably, it is 60,000-280,000. The average molecular weight of sodium carboxymethyl cellulose greatly affects the strength and shape of the aggregate. When the average molecular weight is less than 45,000, the strength of the aggregate α is weak and tends to be minute, so the aggregate β cannot be formed into a desired shape and cannot be a patterned paper having a desired pattern. There is. On the other hand, if the average molecular weight exceeds 300,000, the aggregate β tends to be large or non-uniform, so that it may not be possible to obtain a pattern paper having a pattern with a desired shape.

  In the pattern paper which concerns on this embodiment, it is preferable that the average fiber length of a cellulose fiber or a chemical fiber is 140-3000 micrometers. More preferably, it is 160-750 micrometers, Most preferably, it is 180-300 micrometers. If the thickness is less than 140 μm, the strength of the aggregate α is weak and tends to be minute, and thus the aggregate β cannot be formed into a desired shape, and a pattern paper having a pattern with a desired shape may not be obtained. If it exceeds 3000 μm, it becomes an aggregate in a form in which the fibers are connected to each other by sodium carboxymethyl cellulose, and it tends to be broken by the share in each step, so it may not be possible to make a pattern paper having a pattern of a desired shape. .

  When the pattern paper obtained in the present embodiment is used as a base paper for ink jet printing, an ink jet ink receiving layer is provided on at least one surface, whereby a paper pattern compatible with ink jet printing can be obtained. In the pattern paper manufacturing method according to the present embodiment, it is preferable to further include a step 6 of providing an inkjet ink receiving layer containing amorphous synthetic silica and a water-soluble polymer on at least one surface of the pattern paper. By including amorphous synthetic silica and a water-soluble polymer in the ink-jet ink receiving layer, it is possible to effectively obtain printability, ink absorbability and print density of the ink-jet printer. Moreover, since the transparency of the inkjet ink receiving layer is high, it is possible to make use of the pattern of the aggregate β of the pattern paper.

  The amorphous synthetic silica is a pigment and has a role of absorbing inkjet ink. Amorphous synthetic silica is classified into a dry method, a wet method, and a sol method depending on the production method. This embodiment is not limited to the production method, type and shape of amorphous synthetic silica. Two or more kinds of amorphous synthetic silica can be used in combination.

  Examples of the water-soluble polymer include polyvinyl alcohol derivatives such as polyvinyl alcohol (PVA), carboxy-modified polyvinyl alcohol, and silanol-modified polyvinyl alcohol, starch derivatives such as starch, cationized starch, oxidized starch, and grafted starch, carboxymethyl cellulose, Cellulose derivatives such as hydroxymethyl cellulose, hydroxyethyl cellulose and cellulose sulfate, gelatin, casein, soybean protein, sodium polyacrylate, sodium styrene-maleic anhydride copolymer, sodium polystyrene sulfonate and maleic anhydride resin. This embodiment is not limited to the type of water-soluble polymer. Moreover, unless the effect of this invention is impaired, water-soluble polymer and another binder can be used together. The binder that can be used in combination is preferably a hydrophilic resin. Here, the hydrophilic resin refers to a resin that is easily dispersed in water, and can be used in the form of a dispersion liquid dispersed in water such as an emulsion. Examples of the hydrophilic resin include ethylene-vinyl acetate copolymer (EVA), polyethylene, polyurethane, polyacrylic acid copolymer, polyacrylamide, and styrene-butadiene copolymer. It is preferable to use PVA and EVA in combination from the viewpoint of the absorbability and affinity of the ink-jet ink. In this case, the blending ratio of PVA and EVA is preferably 15:85 to 45:55.

  The inkjet ink receiving layer preferably contains a binder in an amount of 40 to 60 parts by mass with respect to 100 parts by mass of amorphous synthetic silica. More preferably, it is 45-55 mass parts. If it is less than 40 mass parts, the intensity | strength of a coating layer may become weak. If it exceeds 60 parts by mass, the ink absorbability may be inferior.

The ink-jet ink receiving layer can be formed by applying and drying an ink receiving layer coating liquid containing amorphous synthetic silica and a water-soluble polymer on a pattern paper. The coating amount of the inkjet ink receiving layer is preferably ³ to 15 g / m ² in terms of mass after drying. More preferably 5~13g / ^{m 2,} particularly preferably 7~11g / ^{m 2.} If it is less than 3 g / m ² , effective ink jet printer printability may not be obtained. If it exceeds 15 g / m ² , the coating layer may be too thick to make use of the texture of the pattern paper used as the base paper. Moreover, you may mix | blend various inorganic pigments, an adhesive agent, and an additive with the coating liquid for ink receiving layers in the range which does not impair the effect of invention. The ink receiving layer coating liquid may be applied twice or more, and the ink receiving layer may be composed of two or more layers.

  The ink receiving layer coating solution can be applied by a general coater such as an air knife coater, roll coater, blade coater, rod blade coater, bar coater, or die coater. The present embodiment is not limited to this.

  Examples of the drying method after coating include hot air drying, infrared drying, and drum drying, but are not particularly limited in the present embodiment.

  For the purpose of controlling the smoothness of the pattern paper provided with the inkjet ink receiving layer, a calendar process may be performed as necessary. Examples of the calendar include a super calendar, a machine calendar, and a soft calendar, but this method is not particularly limited. Further, post-processing treatments according to various product appearances such as embossing, drilling, and back surface tacking may be performed.

  The outermost layer of the inkjet ink receiving layer may be a gloss layer by a cast coating method. As the cast coating method, a known method such as a wet method, a coagulation method, or a rewet method can be selected. Furthermore, you may perform a calendar process on the surface of a glossy layer. The calendar process can be processed by a known process such as a super calender, a raster press, or a high temperature soft nip calender.

  The pattern paper according to the present embodiment is suitable as a postcard paper. When used as a postcard paper, a pattern may be provided by blending aggregates in both the front layer and the back layer, but the pattern may be blended only in either the front layer or the back layer. More preferably. Furthermore, it is preferable that the layer side where the pattern is not provided is the address side and the layer side where the pattern is provided is the communication side. The address surface is a plain with no pattern, and is easy to read the postal code, address, address, etc., and the communication surface can be provided with a pattern so as to be a postcard sheet having high design value and having a design property. Moreover, it is preferable to provide an inkjet ink receiving layer on the side where the pattern is provided. It can be used as a postcard paper with an ink jet compatible pattern, and the product value can be further improved. Furthermore, by providing a gloss layer by a cast coating method on the outermost layer of the ink-jet ink receiving layer, a photographic-like high-definition image can be expressed.

  Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, “parts” and “%” represent “parts by mass” and “mass%”, respectively, unless otherwise specified. The number of added parts is a value in terms of solid content.

Example 1
"Preparation of white aggregate a"
(Process 1)
In a 1500 liter tank, 104 kg of water, 770 kg of a sodium carboxymethylcellulose aqueous solution having a concentration of 0.30% (Serogen SG-F 3H Cellogen 3H, average molecular weight 220,000: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and titanium oxide (A-110) : Sakai Chemical Industry Co., Ltd.) 2 kg and powdered cellulose fiber (KC Flock W-50S, manufactured by Nippon Paper Chemical Co., Ltd.) 4 kg were uniformly stirred to obtain a mixed solution. Here, when the average fiber length of the powdered cellulose fiber KC floc W-50S was measured with a fiber length measuring instrument (Fiber Lab Analyzer P423037: manufactured by KAJAANI), the average fiber length (Ll) was 240 μm.

(Process 2)
Thereafter, while stirring the mixed solution obtained in Step 1, 30 kg of 10% concentration sulfuric acid band (manufactured by Techno Hokuetsu Co., Ltd.) was added to obtain an aggregate α slurry.

(Process 3)
Next, while stirring the aggregate α slurry obtained in step 2, 0.1 kg of anionic acrylamide (Himoloc SS-100: manufactured by Hymo Co., Ltd.) 80 kg was added and further aggregated. 10 kg of 0.2% concentration cationic acrylamide (RD-7122: manufactured by Seiko PMC) was added to obtain a slurry-like white aggregate β, which was designated as white aggregate a. The slurry was prepared using water so that the total amount became 1000 kg, and a slurry of white aggregate a was obtained. The density | concentration of the slurry of the white aggregate a was 1.3 mass%. In Steps 1 to 3, the stirrer used was a saddle with a wing diameter of 75 cm, and the rotational speed was 400 rpm.

"Preparation of red aggregate b"
In Step 1, 96 kg of water in a 1500 liter tank, 770 kg of a sodium carboxymethylcellulose aqueous solution having a concentration of 0.30% (SG Serogen F-3H Cellogen 3H, average molecular weight 220,000: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), redness 100 g of a pigment (TB1000Red FGN: manufactured by Dainichi Seika Co., Ltd.) stock solution and 4 kg of powdered cellulose fiber (KC Flock W-50S: manufactured by Nippon Paper Chemicals Co., Ltd.) were uniformly stirred to obtain a mixed solution. In steps 2 and 3, red aggregates β were obtained in the same manner as the preparation of white aggregate a, and this was used as red aggregate b. The slurry was prepared using water so that the total amount was 1000 kg to obtain a slurry of red aggregate b. The concentration of the slurry of red aggregate b was 1.1% by mass.

"Production of patterned paper"
“Preparation of papermaking raw material A” (Step 4)
Canadian standard freeness 500ml CSF 1.2% L-BKP pulp slurry 100 parts (conversion to absolute dry pulp), cation starch (trade name Neotac 40T: made by NSC Japan) talc (product) Meitaira Talc: made by Taihei Talc) 5.00 parts, acid rosin sizing agent (trade name AL1200: made by Seiko PMC) 0.400 parts, liquid sulfuric acid band (Techno Hokuetsu Co., Ltd.) 1.00 parts, 4.000 parts of the slurry of white aggregate a was added to a stock prepared by adding 0.0200 parts of a red dye (KF Red B Liquid: Nippon Kayaku Co., Ltd.) to obtain a papermaking raw material A. .

“Preparation of papermaking raw material B” (Step 4)
In the preparation of the papermaking raw material A, a papermaking raw material B was obtained in the same manner as the papermaking raw material A, except that 2.00 parts of the slurry of the red aggregate b was added instead of 4.00 parts of the slurry of the white aggregate a. .

"Paper making" (Process 5)
With butt type round net multilayer paper machine, the first layer and paper stock A, the second layer as a papermaking raw material B, the total basis weight of 120 g / m ² basis weight per layer as 60 g / m ² 2 Layer paper was made and dried to obtain a web. After applying 6% of oxidized starch (Oji Ace A: manufactured by Oji Corn Starch Co., Ltd.) on both sides of the paper web with an on-machine size press so that the dry coating amount is 1.5 g / m ² per side, the pattern is dried. Paper was made. Here, the surface of the first layer is referred to as “surface”, and the surface opposite to the surface (in Example 1, the surface of the second layer) is referred to as “back surface”. Hereinafter, the same applies to other examples and comparative examples. The resulting pattern paper was a pattern paper having a white pattern on the pink background and a red pattern on the pink background.

(Example 2)
In Example 1, a pattern paper was obtained in the same manner as in Example 1 except that the paper material A and the paper material B were made into two layers using a long-mesh multi-layer paper machine. The resulting pattern paper was a pattern paper having a white pattern on the pink background and a red pattern on the pink background. In this example, a multi-sheet long paper machine manufactured by Kobayashi Seisakusho was used as the long paper machine.

(Example 3)
In Example 1, the pattern paper was prepared in the same manner as in Example 1 except that the first layer paper was made with a dry-hat type paper machine and the second layer was made with a bat type paper machine. Obtained. The resulting pattern paper was a pattern paper having a white pattern on the pink background and a red pattern on the pink background. In this embodiment, the dry-tart type circular paper machine is a NEW. EASY. FORMER was used. The dry-hat type circular net paper machine has the structure shown in FIG.

Example 4
“Preparation of papermaking raw material C” (Step 4)
In the preparation of the papermaking raw material A, a papermaking raw material C was obtained in the same manner as the papermaking raw material A, except that 4.00 parts of the white aggregate a slurry was added to 2.00 parts.

"Paper making" (Process 5)
In Example 3, a pattern paper was obtained in the same manner as in Example 3 except that the second layer was changed to the papermaking raw material C. The obtained pattern paper was a pattern paper provided with a white pattern on a pink background on both the front and back surfaces.

(Example 5)
“Preparation of papermaking raw material D” (Step 4)
In the preparation of the papermaking raw material A, a papermaking raw material D was obtained in the same manner as the papermaking raw material A, except that 4.00 parts of the white aggregate a slurry was added to 6.00 parts.

"Paper making" (Process 5)
In Example 3, a pattern paper was obtained in the same manner as in Example 3 except that the first layer was the papermaking raw material D and the second layer was the papermaking raw material A. The obtained pattern paper was a pattern paper provided with a white pattern on a pink background on both the front and back surfaces.

(Example 6)
“Preparation of papermaking raw material E” (Process 4)
In the preparation of the papermaking raw material A, a papermaking raw material E was obtained in the same manner as the papermaking raw material A, except that the slurry of the white aggregate a was not added.

"Paper making" (Process 5)
In Example 3, a pattern paper was obtained in the same manner as in Example 3 except that the second layer was the papermaking raw material E. The obtained pattern paper was a pattern paper provided with a white pattern on the pink background and no pattern on the pink background.

(Example 7)
“Preparation of papermaking raw material F” (Step 4)
In the preparation of the papermaking raw material A, a papermaking raw material F was obtained in the same manner as the papermaking raw material A, except that the red dye (KF Red B liquid: manufactured by Nippon Kayaku Co., Ltd.) and the white aggregate a slurry were not added.

"Paper making" (Process 5)
In Example 3, a pattern paper was obtained in the same manner as in Example 3 except that the second layer was the papermaking raw material F. The obtained pattern paper was a pattern paper provided with a white pattern on a pink background and no pattern on a white background.

(Example 8)
“Preparation of papermaking raw material G” (Process 4)
In the preparation of the papermaking raw material A, a red dye (KF red B liquid: manufactured by Nippon Kayaku Co., Ltd.) was not added, and the slurry of the red aggregate b was replaced with 4.00 parts of the white aggregate a slurry. A papermaking raw material G was obtained in the same manner as the papermaking raw material A except that 4.00 parts were added.

"Paper making" (Process 5)
In Example 6, a pattern paper was obtained in the same manner as in Example 6 except that the first layer was the papermaking raw material G. The obtained pattern paper was a pattern paper having a red pattern on a white background and no pattern on a pink background.

Example 9
In Example 8, in Step 5, the first layer is the papermaking raw material E, the second layer is the papermaking raw material G, the first layer papermaking method is a bat-type circular net papermaking machine, and the second layer papermaking method is Dryt A patterned paper was obtained in the same manner as in Example 8 except that paper was produced as a circular paper machine. The obtained pattern paper was a pattern paper having a pink pattern on the front surface and a red pattern on the white background.

(Example 10)
"Preparation of white aggregate c"
In the preparation of white aggregate a, a 0.30% sodium carboxymethylcellulose aqueous solution (SG Serogen F-3H Cellogen 3H, average molecular weight 220,000: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added to 0.28% sodium carboxymethylcellulose. A slurry of white aggregate c was prepared in the same manner as the slurry of white aggregate a except that it was changed to an aqueous solution (Serogen F-815C, average molecular weight 260,000: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

"Preparation of white aggregate d"
In the preparation of the white aggregate a, a sodium carboxymethyl cellulose aqueous solution having a concentration of 0.30% (SG cellogen F-3H cellogen 3H, average molecular weight 220,000: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was used. A white aggregate d slurry was obtained in the same manner as the white aggregate a slurry except that the aqueous solution (Serogen WS-A, average molecular weight 105,000: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was used.

“Preparation of papermaking raw material H” (Step 4)
In the preparation of the papermaking raw material A, a papermaking raw material H was obtained in the same manner as the papermaking raw material A, except that 4.00 parts of the white aggregate a slurry was changed to 4.00 parts of the white aggregate c slurry.

“Preparation of papermaking raw material I” (Step 4)
In the preparation of the papermaking raw material A, a papermaking raw material I was obtained in the same manner as the papermaking raw material A, except that 4.00 parts of the white aggregate a slurry was changed to 4.00 parts of the white aggregate d slurry.

"Paper making" (Process 5)
The first layer is made with paper dry material H using a dry-mat type multi-layer paper machine, the second layer is made with paper vat raw material I using a vat-type circular paper machine, dried and dried. A two-layer pattern paper having a total basis weight of 120 g / m ² was obtained with a basis weight of 60 g / m ² . The obtained pattern paper was a pattern paper in which a white pattern was provided on a pink background on both the front and back surfaces.

(Example 11)
"Preparation of white aggregate f"
In the preparation of the white aggregate a, a slurry of the white aggregate f was obtained in the same manner as the slurry of the white aggregate a except that the powdered cellulose fiber was not added.

“Preparation of papermaking material L” (Step 4)
In the preparation of the papermaking raw material A, a papermaking raw material L was obtained in the same manner as the papermaking raw material A, except that 4.00 parts of the white aggregate a slurry was changed to 4.00 parts of the white aggregate f slurry.

"Paper making" (Process 5)
A pattern paper was obtained in the same manner as in Example 3 except that the papermaking raw material L was used as the second layer in Example 3. The obtained pattern paper was a pattern paper in which a white pattern was provided on a pink background on both the front and back surfaces.

(Example 12)
"Preparation of white aggregate g"
In the preparation of white aggregate a, a slurry of white aggregate g was obtained in the same manner as the slurry of white aggregate a except that cationic acrylamide was not added.

“Preparation of papermaking raw material M” (Process 4)
In the preparation of the papermaking raw material A, a papermaking raw material M was obtained in the same manner as the papermaking raw material A, except that 4.00 parts of the white aggregate a slurry was changed to 4.00 parts of the white aggregate g slurry.

"Paper making" (Process 5)
In Example 3, a pattern paper was obtained in the same manner as in Example 3 except that the second layer was the papermaking raw material M. The obtained pattern paper was a pattern paper in which a white pattern was provided on a pink background on both the front and back surfaces.

(Example 13)
“Preparation of papermaking raw material N” (Step 4)
In the preparation of papermaking raw material A, 100 parts of a 1.2% L-BKP pulp slurry (converted to absolute dry pulp) with a Canadian standard freeness of 500 ml CSF was used, and a 1.2% concentration unbeaten fine quality with a Canadian standard freeness of 500 ml CSF. Papermaking raw material N in the same manner as papermaking raw material A, except that it was changed to 100 parts of waste paper pulp slurry (converted to absolute dry pulp) and no red dye (KF Red B Liquid: manufactured by Nippon Kayaku Co., Ltd.) was added. Got.

"Paper making" (Process 5)
Using a dry-mat type circular multi-layer paper machine, the first layer is the papermaking raw material A, the second layer is the papermaking raw material N, the third layer is the papermaking raw material F, and the basis weight per layer is 60 g / m ^2. A three-layer papermaking with a total basis weight of 180 g / m ² was performed and dried to obtain a pattern paper. The obtained pattern paper was a pattern paper provided with a white pattern on a pink background and no pattern on a white background.

(Comparative Example 1)
"Preparation of white aggregate e"
In the preparation of the white aggregate a, anionic acrylamide (Himoloc SS-100: manufactured by Hymo) and cationic acrylamide (RD-7122: manufactured by Seiko PMC) were not added. A white aggregate e slurry was obtained in the same manner as the slurry.

“Preparation of papermaking raw material J” (Process 4)
In the preparation of the papermaking raw material A, a papermaking raw material J was obtained in the same manner as the papermaking raw material A, except that the white aggregate a slurry was changed to the white aggregate e slurry.

"Paper making" (Process 5)
In Example 3, a pattern paper was obtained in the same manner as in Example 3 except that the first layer was the papermaking raw material J and the second layer was the papermaking raw material E. The obtained pattern paper was a pattern paper provided with a fine white pattern with inferior visibility on a pink background and no pattern on a pink background.

(Comparative Example 2)
“Preparation of papermaking raw material K” (Step 4)
In the preparation of papermaking raw material A, papermaking was performed except that 2.00 parts of white aggregate a slurry and 2.00 parts of red aggregate b slurry were added instead of 4.00 parts of white aggregate a slurry. A papermaking raw material K was obtained in the same manner as the raw material A.

"Paper making" (Process 5)
Using a vat-type circular net paper machine, the papermaking raw material K was made in one layer with a basis weight of 120 g / m ² and dried to obtain a patterned paper. The obtained pattern paper was a pattern paper having a pink background on the front and back, a white pattern and a red pattern mixed together, and the pattern visibility was poor.

  It shows in Table 1 about the structure of the pattern paper of an Example and a comparative example, and the color tone by visual observation.

  Table 2 shows the evaluation results of the pattern papers obtained in Examples and Comparative Examples. Evaluation methods and evaluation criteria are as follows.

"Pattern amount"
The total area of the pattern appearing on the arbitrarily selected 100 mm × 100 mm square of the obtained pattern paper was determined by image analysis, and the total area was taken as the pattern amount. Many, medium, and small evaluations were performed based on the pattern amount on the surface of the pattern paper of Example 1.
Multi: The total area exceeds 125% of the total area on the surface of Example 1.
Middle: The total area is 75% or more and less than 125% of the total area on the surface of Example 1.
Small: The total area is less than 75% of the total area on the surface of Example 1.
-: The aggregate is not added.

"Uniformity of pattern"
The uniformity was evaluated by visual observation of the pattern uniformity of samples obtained by cutting the pattern papers of Examples and Comparative Examples into A4 size.
(Double-circle): The aggregate pattern is disperse | distributing very uniformly on the paper surface, and is a practical use level.
○ 1: Although the aggregate pattern is slightly unevenly distributed, it is a practical lower limit level that causes no practical problems.
○ 2: The aggregate pattern has a long and narrow shape, but is uniformly distributed, and is a practical lower limit level that causes no practical problems.
○ 3: The aggregate pattern is distributed in a slight streak shape, but it is a practical lower limit level that causes no practical problems.
X: The aggregate pattern is non-uniform and is not practical.
-: Since no aggregate is added, there is no pattern.

“Agglomerate pattern size” (pattern size)
The area of each pattern appearing on the arbitrarily selected 100 mm × 100 mm square of the obtained pattern paper is obtained by image analysis, and the average area per aggregate is large, medium, small, A minute evaluation was performed.
Large: The average area is 10 mm ² or more.
Middle: The average area is 4 mm ² or more and less than 10 mm ² .
Small: The average area is 1 mm ² or more and less than 4 mm ² .
Minute: Average area is less than 1 mm ² .

"Visibility evaluation" (pattern visibility)
The shape of the aggregate that appeared on the paper surface of the pattern paper was visually determined.
(Double-circle): The visibility of an aggregate is favorable and is a practical use level.
A: Agglomerates are slightly small but can be visually recognized as a pattern, which is a practical lower limit level.
(Triangle | delta): Since an aggregate is destroyed and is small, it is a practically impossible level inferior to the texture as a pattern paper which is hard to see as a pattern.
X: Since the aggregate is minute and does not form a desired pattern, it is a practically unusable level.
-: Since no aggregate is added, there is no pattern.

  Next, an ink-jet ink receiving layer was provided on the pattern paper of Example 8 to prepare a pattern paper compatible with ink-jet printing.

(Example 14)
“Preparation of coating liquid A for ink receiving layer” (step 6)
As a pigment, 50.0 parts of amorphous synthetic silica having an average particle diameter of 7 μm (Silojet P407: manufactured by Grace Devison) and 50.0 parts of amorphous synthetic silica having an average particle diameter of 6 μm (74 × 6500: manufactured by Grace Devison) And 0.500 parts of acetic acid as a pH adjuster were added to the mixture, and a 25% pigment slurry was prepared with a cowless disperser (LABORTECHNK RW-28, manufactured by Terai Scientific Instruments Co., Ltd.). Into this pigment slurry, 17.5 parts by weight of polyvinyl alcohol (PVA-117: manufactured by Kuraray Co., Ltd.) and an ethylene vinyl acetate binder (Sumikaflex 450: manufactured by Sumitomo Chemical Co., Ltd.) with respect to 100 parts by weight of the pigment. 0 parts were added and stirred, and water was further added to obtain a coating solution for an ink receiving layer having a solid content concentration of 23%.

"Formation of inkjet ink receiving layer A"
Using the pattern paper obtained in Example 8 as the base paper, the ink-receiving layer coating liquid A was applied to the surface of the first layer with a bar so that the dry mass was 8 g / m ^2, and 120 ° C. with a dryer. The inkjet ink receiving layer A was formed by drying with hot air.

"Smoothing"
Next, a surface treatment was performed using a soft calender under the conditions of a linear pressure of 30 kg / cm, 25 ° C., and 2 nips and 1 pass to obtain a pattern paper with an inkjet ink receiving layer.

(Example 15)
A pattern paper with an inkjet ink receiving layer was prepared in the same manner as in Example 14, except that the surface on which the inkjet ink receiving layer was formed was the surface of the second layer of the pattern paper obtained in Example 8. .

(Example 16)
A pattern paper with an ink-jet ink receiving layer was prepared in the same manner as in Example 14 except that the coating liquid A for ink receiving layer was applied so as to have a dry mass of 15 g / m ² .

(Example 17)
“Preparation of ink receiving layer coating solution A ′” (step 6)
In the preparation of the coating liquid A for the ink receiving layer, ethylene vinyl acetate binder (Sumikaflex 450: manufactured by Sumitomo Chemical Co., Ltd.) is not added, and polyvinyl alcohol (PVA-117: manufactured by Kuraray Co., Ltd.) is 41.5 parts by dry mass. Except for the above, an ink receiving layer coating solution A ′ having a solid concentration of 23% was obtained in the same manner as the ink receiving layer coating solution A.

  In Example 14, a pattern paper with an inkjet ink receiving layer was prepared in the same manner as in Example 14 except that the ink receiving layer coating liquid A was changed to the ink receiving layer coating liquid A ′.

(Comparative Example 3)
“Preparation of coating liquid B for ink receiving layer”
50.0 parts of calcined kaolin (Ansilex 90: manufactured by Engelhardt) and 50.0 parts of calcium carbonate (Hacuenka PZ: manufactured by Shiroishi Calcium Co.) are mixed. 500 parts was added, and 35% pigment slurry was prepared with a cowless disperser (LABORTECHNK RW-28, manufactured by Terai Scientific Instruments Co., Ltd.). To this pigment slurry, 17.5 parts of polyvinyl alcohol (PVA-117: manufactured by Kuraray Co., Ltd.) and 24.0 parts of ethylene vinyl acetate binder (Sumikaflex 450: manufactured by Sumitomo Chemical Co., Ltd.) are added and stirred, and water is further added. Thus, an ink receiving layer coating solution B having a solid content concentration of 23% was obtained.

  In Example 14, a pattern paper with an ink-jet ink receiving layer was prepared in the same manner as in Example 14 except that the ink receiving layer coating liquid A was changed to the ink receiving layer coating liquid B.

(Comparative Example 4)
“Preparation of coating liquid C for ink receiving layer”
50.0 parts of amorphous synthetic silica (Silojet P407: manufactured by Race Devison) and 50.0 parts by weight of amorphous synthetic silica (74 × 6500: manufactured by Grace Devison) were mixed, and water and pH were added to the mixture. Acetic acid (0.500 parts) was added as a regulator, and a 28% pigment slurry was prepared with a cowless disperser (LABORTECHNK RW-28, manufactured by Terai Scientific Instruments Co., Ltd.). To this pigment slurry, 41.5 parts by mass of an ethylene vinyl acetate binder (Sumikaflex 450: manufactured by Sumitomo Chemical Co., Ltd.) is added and stirred, water is further added, and an ink receiving layer coating liquid C having a solid content concentration of 23%. Got.

  In Example 16, a pattern paper with an ink-jet ink receiving layer was prepared in the same manner as in Example 16 except that the ink receiving layer coating liquid A was changed to the ink receiving layer coating liquid C.

  Table 3 shows the evaluation results of the pattern papers with the ink-jet ink receiving layers obtained in Examples and Comparative Examples. Evaluation methods and evaluation criteria are as follows.

"Inkjet printing suitability"
About the sample which cut | disconnected the pattern paper with the ink-jet ink receiving layer of the obtained Example and comparative example to A4 size, a photographic image was printed using a commercially available full-color ink-jet printer (PM-A950: Seiko Epson), and the boundary Ink-jet printing suitability was evaluated with respect to the printing blur of the part and the printing density of the coloring part. Evaluation methods and evaluation criteria are as follows.

[Print blur at the boundary] (Print blur)
(Double-circle): There is no printing blur of a boundary part, and it is very favorable and is a practical use level.
○: Although printing blur is slightly seen at the boundary, it is good and at the practical lower limit level.
(Triangle | delta): The printing blur of a boundary part is seen and it is a use impossibility level.
X: The printing blur at the boundary is large, and the level is not practical.

[Color density printing density] (Print density)
(Double-circle): The printing density of a color development part is very dark and is very favorable, and it is a practical use level.
○: The print density of the color-developing part is dark and good, and is at a practical level.
(Triangle | delta): The printing density of a color development part is a little thin, and a practical use level.
X: The print density of the color-developing portion is thin and is not practical.

"Texture evaluation" (texture)
The visibility of the aggregate as the pattern of the pattern paper with the inkjet ink receiving layer was visually evaluated.
(Double-circle): The texture of the color tone of an aggregate and paper surface is favorable, and is a practical use level.
A: The color tone of the aggregate and the paper surface can be visually recognized, and there is no practical problem (lower limit for practical use).
(Triangle | delta): The visibility of an aggregate is inferior, the color tone of a paper surface is dull and it is inferior to the texture as a pattern paper, and is a practically unusable level.
X: Aggregates are concealed in the ink-jet ink receiving layer and cannot be visually recognized.

  As shown in Table 1, the pattern paper according to the present invention can realize various variations by combining the color tone of the paper surface and the color tone of the aggregate. For example, a combination of a white pattern on a pink background such as the surface of Example 1 to Example 3, a combination of providing a red pattern on a pink background such as the back surface of Example 1 to Example 3, the surface of Example 8 and This is a combination in which a red pattern is provided on a white background such as the back surface of Example 9. In addition, as shown in Examples 6 to 9, a pattern can be provided by adding an aggregate only to one side. As shown in Examples 1 to 3 and Examples 7 to 9, the color tone of the pattern and the color tone of the pattern paper itself can be changed on the front and back of the pattern paper.

  As shown in Table 1 and Table 2, the amount of pattern can be adjusted by adjusting the amount of aggregate added to the papermaking material. For example, Example 4 is a pattern paper in which a white pattern is provided on a pink background on the front and back surfaces, but the amount of agglomeration in the second layer papermaking raw material is larger than the amount of aggregate added to the first layer papermaking raw material. Since the amount of aggregate added was reduced, the back side became a pattern paper with less pattern amount than the front side. Example 5 is a pattern paper in which a white pattern is provided on a pink background on the front and back surfaces, but the amount of aggregate in the second layer papermaking raw material is larger than the amount of the aggregate added to the first layer papermaking raw material. Since the amount added was increased, the back side became a pattern paper with a larger amount of pattern than the front side. Furthermore, for example, the size of the aggregate can be selected according to the average molecular weight of carboxymethylcellulose as in Example 10 and the presence or absence of addition of cellulose fibers or chemical fibers to the carboxymethylcellulose aqueous solution as in Example 11. It is possible to make the pattern size different between the front and back sides. Further, in Example 13, as the three-layer papermaking, waste paper pulp was used for the middle layer, and the pattern was formed by blending the aggregate only on the surface layer. Therefore, even when the paper thickness was increased, the pattern distribution was uniform. I was able to get paper. The pattern paper as in Example 13 is suitable for postcards because the back layer is white with no pattern.

  In Examples 1 to 13, the white aggregates a, c, d, f and g and the red aggregate b were all stabilized by sequentially adding a metal salt and an acrylic acid copolymer type flocculant. Since it had a shape, the size of the aggregate as a pattern was suitable for pattern paper, and the pattern visibility was excellent.

  It was confirmed that the agglomerates for pattern paper can be more uniformly distributed on the paper surface by making paper using a dry-tart type net paper machine as a paper making method.

  On the other hand, in Comparative Example 1 using the white aggregate e prepared without using an acrylic acid copolymer type flocculant, the aggregate was destroyed by the shares in the aggregate preparation process, pump transfer process, and papermaking process. Therefore, the visibility of the pattern of the obtained pattern paper was inferior. In Comparative Example 2, since the single-layer paper making is performed, it is not possible to make the color tone of the pattern paper and the color tone of the pattern different from each other. Furthermore, since it is a single-layer papermaking, the blending amount of the agglomerates as a pattern cannot be changed between the front and back sides, and a pattern cannot be provided only on either the front or back side.

  As shown in Table 3, the ink jet pattern papers of Examples 14 to 17 are compatible with good ink jet printing suitability and texture as a pattern paper, and can be used for various unprecedented needs. .

  On the other hand, although the pattern paper of Example 8 was used for the comparative example 3, since the amorphous | non-crystalline synthetic | combination silica was not contained in the inkjet ink receiving layer, it became inferior to inkjet suitability. In Comparative Example 4, the pattern paper of Example 8 was used as the base paper, but it did not contain a water-soluble polymer, and therefore was inferior in inkjet suitability.

  The pattern paper according to the present invention can be suitably used in industries such as decoration, packaging, and printing that use the paper and in the paper manufacturing industry. For example, it can be suitably used for postcard paper, printing paper, and packaging paper.

DESCRIPTION OF SYMBOLS 10 Bat type | formula net paper machine 11 Butt 12 Cylindrical cylinder 13 Couch roll 15 Wet sheet 16 Felt 21 Butt liquid level 22 Cylindrical cylinder inner liquid level 24 Flowing down 50 Drynut type net paper machine 51 Paper supply slit 52 Cylindrical cylinder 53 Couch roll 55 Paper layer 56 Felt

Claims (11)

A multi-layer pattern paper having two or more layers having a surface layer and a back layer,
Either one of the surface layer or the back layer or both layers contains an aggregate β,
The agglomerates beta, comprising attached to each other aggregate alpha by liquid polymeric flocculants acrylic acid copolymer type, a larger aggregates, the aggregated body alpha, sodium carboxymethylcellulose, a sodium ion By substituting with other metal ions, it is a particulate aggregate formed by agglomerating in the state of incorporating one or more substances selected from the group consisting of pigment, cellulose fiber and chemical fiber. Characteristic pattern paper.   The pattern paper according to claim 1, wherein the aggregate α further contains a dye.   The pattern according to claim 1 or 2, wherein an acrylic acid copolymer type liquid polymer flocculant is attached to the surface of both or one of the aggregate α and the aggregate β. paper.   The pattern paper according to any one of claims 1 to 3, wherein the acrylic acid copolymer type liquid polymer flocculant is an anionic polyacrylamide.   The average molecular weight of the said sodium carboxymethylcellulose is 45,000-300,000, The pattern paper as described in any one of Claims 1-4 characterized by the above-mentioned.   The pattern paper according to any one of claims 1 to 5, wherein an average fiber length of the cellulose fiber or the chemical fiber taken into the aggregate α is 140 to 3000 µm.   The pattern according to any one of claims 1 to 6, further comprising an ink-jet ink receiving layer containing amorphous synthetic silica and a water-soluble polymer on at least one surface of the pattern paper. paper. A method for producing a pattern paper having two or more layers having a surface layer and a back layer,
Mixing one or more substances selected from the group consisting of pigment, cellulose fiber, and chemical fiber with an aqueous sodium carboxymethyl cellulose solution; and
A step 2 of adding an aqueous metal salt solution to the mixture obtained in step 1 and forming an aggregate α by stirring;
Step 3 of forming an aggregate β by adding an acrylic acid copolymer type liquid polymer flocculant to the liquid containing the aggregate α obtained in Step 2;
Step 4 of preparing the surface layer paper material and the back layer paper material by adding the aggregate β obtained in Step 3 to one or both of the paper material for surface layer and the paper material for back layer ,
And a process 5 for producing the paper stock.   9. The pattern paper manufacturing method according to claim 8, wherein the step 5 performs papermaking using a dry-hat type circular net paper machine.   The acrylic polymer type liquid polymer flocculant is an anionic polyacrylamide and a cationic polyacrylamide, and after adding the anionic polyacrylamide, the cationic polyacrylamide is added. A method for producing a patterned paper according to 8 or 9.   11. The method according to claim 8, further comprising a step 6 of providing an inkjet ink receiving layer containing amorphous synthetic silica and a water-soluble polymer on at least one surface of the pattern paper. A method for producing a patterned paper as described in 1.

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