Dictionary paper and preparation method thereof

Abstract

The present application relates to the technical field of papermaking, and provides a dictionary paper and a preparation method thereof. The method comprises: mixing a first screened slurry with a composite filler to obtain a first mixed slurry, and mixing a second screened slurry with a composite filler to obtain a second mixed slurry; using the first mixed slurry to prepare a bottom wet paper layer, using an interface agent to prepare an interface layer on the bottom wet paper layer, and using the second mixed slurry to prepare a surface wet paper layer on the interface layer to obtain a wet paper sheet; drying the wet paper sheet once to obtain a paper sheet to be sized; performing surface sizing treatment on the paper sheet to be sized to obtain a sized paper sheet; wherein the surface sizing agent comprises enzymatic starch, a water repellent and a cationic polyacrylamide; performing secondary drying and calendering on the sized paper sheet to obtain a paper sheet with a grammage of 40 to 50 g / m 2 The dictionary paper prepared by the present application has good strength and tear resistance, and high opacity, and can be used for printing books such as Xinhua Dictionary.

Description

Technical Field

[0001] The present application relates to the technical field of papermaking, and in particular to a dictionary paper and a preparation method thereof. Background Art

[0002] Dictionary paper is a high-grade thin paper for books and periodicals. It is mainly used for printing dictionaries (for example, Xinhua Dictionary, etc.), encyclopedias, classic books and other books with many pages, high usage rate and easy to carry.

[0003] The hand development of primary school students (especially those in grades one and two) is not yet complete, and they still have some difficulty in controlling fine hand movements. The weight of traditional dictionary paper is generally less than 40g / m 2 The paper strength and tear resistance are poor, and primary school students can easily tear the dictionary pages due to poor control when turning the pages. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of this application is to provide a dictionary paper and a preparation method thereof. The preparation method of this application can produce a dictionary paper with a basis weight of 40 to 50 g / m 2 The dictionary paper has good strength and tear resistance and high opacity.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted in this application is as follows:

[0006] In a first aspect, the present application provides a method for preparing dictionary paper, comprising:

[0007] Mixing and screening coniferous wood pulp, hardwood wood pulp, dry damaged pulp and wet damaged pulp in a mass ratio of 40-50:60-70:0-10:0-10 to obtain a first screened pulp and a second screened pulp, wherein the average fiber length of the first screened pulp is 0.78-0.88 mm, and the average fiber length of the second screened pulp is 0.90-0.98 mm;

[0008] The first screened slurry is mixed with a composite filler to obtain a first mixed slurry, and the second screened slurry is mixed with a composite filler to obtain a second mixed slurry; wherein the composite filler is porous calcium silicate and kaolin;

[0009] Using the first mixed slurry to prepare a bottom wet paper layer, using an interface agent to prepare an interface layer on the bottom wet paper layer, and using the second mixed slurry to prepare a surface wet paper layer on the interface layer to obtain a wet paper sheet;

[0010] Performing a drying process on the wet paper sheet to obtain a paper sheet to be sizing;

[0011] The paper sheet to be sized is subjected to surface sizing treatment to obtain the sized paper sheet; wherein the surface sizing agent used in the surface sizing treatment comprises enzymatic starch, water repellent and cationic polyacrylamide; the double-sided sizing amount of the surface sizing agent is 10-12 g / m 2 ;

[0012] The sized paper is subjected to secondary drying and calendering to obtain a basis weight of 40-50g / m 2 Dictionary paper.

[0013] In a second aspect, an embodiment of the present application provides a dictionary paper, which is prepared according to the preparation method of the dictionary paper of the first aspect.

[0014] The beneficial effects of this application include at least:

[0015] The dictionary paper preparation method provided in the embodiment of the present application comprises the following steps: adding a composite filler composed of porous calcium silicate and kaolin to a first screened slurry and a second screened slurry respectively to obtain a first mixed slurry and a second mixed slurry; preparing a bottom wet paper layer by using the first mixed slurry, preparing an interface layer on the bottom wet paper layer by using an interface agent, and preparing a surface wet paper layer on the interface layer by using the second mixed slurry to obtain a wet paper sheet with a double-layer structure; and performing surface sizing treatment on the paper sheet to be sized by using a specific surface sizing agent, and controlling the double-sided sizing amount to be 10 to 12 g / m 2 , the quantitative is 40~50g / m 2 The dictionary paper has good strength and tear resistance and high opacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 It is a structural schematic diagram of a dictionary paper provided in an embodiment of the present application;

[0018] Figure 2 is a structural schematic diagram of a wet paper sheet provided in an embodiment of the present application;

[0019] Figure 3 It is a schematic diagram of the process flow of preparing a dictionary paper provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail in conjunction with the embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present application, but the implementation methods of the present application are not limited thereto.

[0021] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which this application belongs. The experimental reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the amounts of experimental reagents, unless otherwise specified, are all the amounts of reagents used in conventional experimental operations; and the experimental methods, unless otherwise specified, are all conventional methods.

[0022] In a first aspect, the present application provides a method for preparing dictionary paper, comprising:

[0023] S1. Mix and screen coniferous wood pulp, hardwood wood pulp, dry damaged pulp, and wet damaged pulp in a mass ratio of 40-50:60-70:0-10:0-10 to obtain a first screened pulp and a second screened pulp, wherein the average fiber length of the first screened pulp is 0.78-0.88 mm, and the average fiber length of the second screened pulp is 0.90-0.98 mm;

[0024] S2, mixing the first screened slurry with a composite filler to obtain a first mixed slurry, and mixing the second screened slurry with a composite filler to obtain a second mixed slurry; wherein the composite filler is porous calcium silicate and kaolin;

[0025] S3, using the first mixed slurry to prepare a bottom wet paper layer, using an interface agent to prepare an interface layer on the bottom wet paper layer, and using the second mixed slurry to prepare a surface wet paper layer on the interface layer to obtain a wet paper sheet;

[0026] S4, performing a drying process on the wet paper sheet to obtain a paper sheet to be sizing;

[0027] S5, performing surface sizing treatment on the paper sheet to be sized to obtain a sized paper sheet; wherein the surface sizing agent used in the surface sizing treatment includes enzymatic starch, water repellent and cationic polyacrylamide; the double-sided sizing amount of the surface sizing agent is 10-12 g / m 2 ;

[0028] S6, the sized paper is subjected to secondary drying and calendering to obtain a basis weight of 40-50g / m 2 Dictionary paper.

[0029] In some embodiments, in the above step S1, the coniferous wood pulp may be bleached coniferous wood pulp (such as bleached sulfite coniferous wood pulp); the broadleaf wood pulp may be bleached broadleaf wood pulp (such as bleached sulfite broadleaf wood pulp).

[0030] Optionally, the coniferous wood pulp may be Canadian "Continental" or "Lion" coniferous chemical pulp.

[0031] Optionally, the broadleaf wood pulp uses Brazilian "Goldfish" brand or Canadian "Knight" brand broadleaf chemical mechanical pulp.

[0032] Dry damaged pulp generally refers to some dry damaged scraps or unqualified products produced in the process of producing dictionary paper, which is obtained by pulping with a pulping machine.

[0033] Wet-damaged pulp generally refers to some wet-damaged scraps or unqualified products produced in the process of producing dictionary paper, which are obtained by pulping with a pulper.

[0034] Figure 1 It is a schematic diagram of a pulping process flow provided in an embodiment of the present application.

[0035] In some embodiments, see Figure 1 In the above step S1, the bleached sulfite softwood pulp is conveyed to the hydraulic pulper for disintegration via a chain conveyor, and the pulp after disintegration is pumped to the pulp storage tank, and then enters the softwood pulp beating system, and is pulped by four ￠600 double disc refiners in series at constant power, and the pulping quality is automatically controlled to ensure that the beating effect is stable and consistent. The qualified pulp enters the softwood pulp post-beating pulp tank for pulping. The bleached sulfite hardwood pulp is conveyed to the hydraulic pulper for disintegration via a chain conveyor, and the pulp after disintegration is pumped to the pulp storage tank, and then enters the hardwood pulp beating system, and is pulped by four ￠600 double disc refiners in series at constant power, and the pulping quality is automatically controlled to ensure that the beating effect is stable and consistent. The qualified pulp enters the hardwood pulp post-beating pulp tank for pulping. The dry damaged paper from the paper machine and the finishing section is crushed by the hydraulic pulper and then sent to the pulp storage tank by a pulp pump. It is then deflated and pulped by the high-frequency deflaker and double-disc refiner, and then enters the dry-beating pulp tank to be mixed. The wet damaged paper from the paper machine is screened by the arc screen and enters the pulp storage tank to be mixed. The beaten coniferous pulp, hardwood pulp, dry damaged pulp, and wet damaged pulp are transported to the pulp mixing tank according to the mass ratio of 40-50:60-70:0-10:0-10 through the automatic metering control system for mixing and mixing. After that, the mixed pulp of coniferous pulp, hardwood pulp, wet damaged pulp, and dry damaged pulp is screened to obtain the first screened pulp and the second screened pulp, wherein the average fiber length of the first screened pulp is 0.78-0.88 mm, and the average fiber length of the second screened pulp is 0.90-0.98 mm.

[0036] In some embodiments, in the above step S2, the first sieved slurry obtained in the above step S1 is mixed with a composite filler in a mass ratio of 10:1 to 3 (for example, 10:1, 10:2 or 10:3, etc.) to obtain a first mixed slurry. The mass ratio of porous calcium silicate to kaolin in the composite filler is 1 to 4:6 (for example, 1:6, 2:6, 3:6 or 4:6, etc.).

[0037] In some embodiments, in the above step S2, the second sieved slurry obtained in the above step S1 is mixed with the composite filler in a mass ratio of 10:1 to 2 (for example, 10:1 or 10:2, etc.) to obtain a second mixed slurry. The mass ratio of porous calcium silicate to kaolin in the composite filler is 1 to 4:6 (for example, 1:6, 2:6, 3:6 or 4:6, etc.).

[0038] In some embodiments, the average particle size of porous calcium silicate is 18-22 μm; the average particle size of kaolin is 1-2 μm.

[0039] In some embodiments, porous calcium silicate can be prepared by the following steps: mixing fly ash with sodium hydroxide solution so that the silicon in the fly ash exists in the liquid phase in the form of sodium salt, then filtering to separate the solid and liquid, and collecting the filtrate; fully mixing the filtrate (mainly silicon dioxide) with lime milk to generate calcium silicate and sodium hydroxide, and then filtering and drying to obtain porous calcium silicate. The mixing mass ratio of the filtrate to the lime milk is 0.95 to 1:0.5.

[0040] The porous calcium silicate of the embodiment of the present application can be prepared from fly ash as raw material, so that fly ash can be "turned into treasure". By adding porous calcium silicate and kaolin, it can replace traditional calcium carbonate filler, expand more types of papermaking fillers, and help promote the continuous development and innovation of papermaking fillers.

[0041] The opacity and tear strength of paper can be improved by adding a composite filler consisting of porous calcium silicate and kaolin in a specific ratio.

[0042] In some embodiments, in the above step S3, a bottom wet paper layer is prepared using the first mixed slurry, an interface layer is prepared on the bottom wet paper layer using an interface agent, and a surface wet paper layer is prepared on the interface layer using the second mixed slurry to obtain a wet paper sheet.

[0043] As an example, a schematic diagram of the structure of a wet paper sheet in an embodiment of the present application is as follows: Figure 2 The wet paper sheet includes a bottom wet paper layer 201, an interface layer 202 and a surface wet paper layer 203 from bottom to top.

[0044] In some embodiments, the interface agent used to prepare the interface layer 202 includes at least two of nanocellulose, sodium carboxymethyl cellulose, and polyvinyl alcohol.

[0045] In one example, the interfacial agent includes nanocellulose and polyvinyl alcohol, wherein the mass ratio of nanocellulose to polyvinyl alcohol is 0.8-1:1-3. Specifically, the mass ratio of nanocellulose to polyvinyl alcohol can be 0.8:1, 0.8:2, 0.8:3, 1:1, 1:2 or 1:3, etc.

[0046] In another example, the interface agent includes sodium carboxymethyl cellulose and polyvinyl alcohol. The mass ratio of sodium carboxymethyl cellulose to polyvinyl alcohol is 1-2:1-3. Specifically, the mass ratio of sodium carboxymethyl cellulose to polyvinyl alcohol can be 1:1, 1:2, 1:3, 2:1 or 2:3.

[0047] In another example, the interfacial agent includes nanocellulose, sodium carboxymethyl cellulose and polyvinyl alcohol. The mass ratio of nanocellulose, sodium carboxymethyl cellulose and polyvinyl alcohol is 0.8-1:1-2:1-3. Specifically, the mass ratio of nanocellulose, sodium carboxymethyl cellulose and polyvinyl alcohol can be 0.8:1:1, 0.8:1:2, 0.8:1:3, 0.8:2:1, 1:1:1 or 1:2:3, etc.

[0048] By using a first mixed slurry to prepare a bottom wet paper layer, using a specific interface agent to prepare an interface layer on the bottom wet paper layer, and then using a second mixed slurry to prepare a surface wet paper layer on the interface layer, a dictionary paper with a double-layer pulp structure having good structural properties, good paper strength and tear resistance, and high opacity can be obtained.

[0049] In some embodiments, in the above step S5, the preparation steps of enzymatic starch are as follows:

[0050] Cassava starch or corn starch is used as a starting material, and alpha-amylase is used to perform enzymatic degradation on the starting material to obtain enzymatic starch with a viscosity of 40 to 45 mPa·s; wherein the use concentration of the alpha-amylase is 0.08 mL / kg of the starting material, that is, 0.08 mL of alpha-amylase is added to 1 kg of the starting material for enzymatic degradation.

[0051] In some embodiments, in the above step S5, the water repellent is a modified melamine formaldehyde resin. The modified melamine formaldehyde resin has an appearance of a colorless or light yellow transparent viscous liquid, a solid content of 6.6%±2%, a free formaldehyde content of ≤2%, a pH value of 7 to 9, a viscosity (25°C) of 100 to 500 mPa·s, and a water solubility (1:10 dilute solution) with no stratification or precipitation.

[0052] In some embodiments, in the above step S5, the mass ratio of enzymatic starch, water repellent and cationic polyacrylamide in the surface sizing agent is 100:12-15:0.1-0.2, for example, it can be 100:12:0.1, 100:13:0.1, 100:14:0.1, 100:15:0.1 or 100:12:0.2, etc.

[0053] In some embodiments, in the above step S6, the pressure of the calendering treatment is 80 to 150 kN / m. For example, the calendering pressure can be 80 kN / m, 85 kN / m, 90 kN / m, 100 kN / m or 150 kN / m.

[0054] By controlling the calendering pressure to 80-150 kN / m, the sized paper sheet is calendered to make the paper structure more compact, reduce the fiber-air or filler-air interface that can scatter light, and help improve the opacity of the paper.

[0055] In a second aspect, an embodiment of the present application further provides a dictionary paper, which is prepared according to the preparation method of the dictionary paper in the first aspect.

[0056] The basis weight of the dictionary paper prepared by the preparation method provided in the embodiment of the present application is 40-50 g / m 2 , has good strength and tear resistance, and high opacity.

[0057] The dictionary paper provided in the embodiment of the present application can be used for printing books such as Xinhua Dictionary, English-Chinese Dictionary, etc.

[0058] Figure 3 It is a schematic diagram of the process flow of preparing a dictionary paper provided in an embodiment of the present application.

[0059] See also Figure 3 The process system for implementing the method for preparing dictionary paper of the embodiment of the present application includes a pulp preparation pool 101, a pulp forming pool 102, a pulp mixing box 103, a pulp flushing pool 104, a pulp flushing pump 105, a slag removal system 106, a pressure screen 107, a stock flow box 108, a fourdrinier section 109, a pressing section 110, a front drying section 111, a surface sizing machine 112, a rear drying section 113, a calender 114 and a paper reel 115, which are connected in sequence through pipelines (pipes) or connecting components (such as conveyor belts, etc.).

[0060] The stock preparation tank 101 includes a first stock preparation tank and a second stock preparation tank with the same or different structures; the stock forming tank 102 includes a first stock forming tank and a second stock forming tank with the same or different structures; the stock mixing box 103 includes a first stock mixing box and a second stock mixing box with the same or different structures; the stock flushing tank 104 includes a first stock flushing tank and a second stock flushing tank with the same or different structures; the stock flushing pump 105 includes a first stock flushing pump and a second stock flushing pump with the same or different structures; the slag removal system 106 includes a first slag removal system and a second slag removal system with the same or different structures; the pressure screen 107 includes a first pressure screen and a second pressure screen with the same or different structures; the headbox 108 includes a first headbox and a second headbox with the same or different structures. Both the first headbox and the second headbox can be closed headboxes with a cross-section quantitative adjustment. The fourdrinier wire section 109 can be a 1880 / 450 fourdrinier wire multi-cylinder tissue paper machine.

[0061] The preparation method of dictionary paper provided in the embodiment of the present application comprises the following steps:

[0062] Process 1: Slurry preparation:

[0063] The beaten softwood pulp, hardwood pulp, dry damaged pulp, and wet damaged pulp are mixed and screened in a mass ratio of 40-50:60-70:0-10:0-10 to obtain a first screened slurry and a second screened slurry, and then the first screened slurry is transported to the first slurry preparation tank of the slurry preparation tank 101, and the second screened slurry is transported to the second slurry preparation tank of the slurry preparation tank 101. A composite filler (a composite of porous calcium silicate and kaolin in a mass ratio of 1-4:6) is added to the first slurry preparation tank, and the mass ratio of the first screened slurry to the composite filler is 10:1-3 to obtain a first mixed slurry, which is then transported to the first slurry preparation tank of the slurry preparation tank 102. A composite filler (a compound of porous calcium silicate and kaolin in a mass ratio of 1 to 4:6) is added into the second slurry preparation tank, the mass ratio of the second screened slurry to the composite filler is 10:1 to 2, and a second mixed slurry is obtained, which is transported to the second slurry preparation tank of the slurry preparation tank 102.

[0064] Process 2: Slurry preparation:

[0065] The first mixed slurry in the first stock tank is transported to the first stock mixing box of the stock mixing box 103 for adjustment, and then enters the first stock tank of the stock washing tank 104, and then the impeller of the first stock pump in the stock washing pump 105 rotates at high speed, so that the first mixed slurry is fully mixed with the concentrated white water, and then enters the first deslagging system of the deslagging system 106, and a small amount of white water is added at the same time, and then passes through the first pressure screen (in-flow pressure screen) of the pressure screen 107, and then enters the first headbox of the headbox 108. The second mixed slurry in the second stock tank is transported to the second stock mixing box of the stock mixing box 103 for adjustment, and then enters the second stock washing tank of the stock washing tank 104, and then the impeller of the second stock pump in the stock washing pump 105 rotates at high speed, so that the second mixed slurry is fully mixed with the concentrated white water, and then enters the second deslagging system of the deslagging system 106, and a small amount of white water is added at the same time, and then passes through the second pressure screen (in-flow pressure screen) of the pressure screen 107, and then enters the second headbox of the headbox 108.

[0066] Process 3: Forming, pressing and primary drying:

[0067] The first mixed slurry flowing out of the first headbox is formed through the fourdrinier wire section 109 to obtain a bottom wet paper layer; an interface layer is prepared on the bottom wet paper layer using an interface agent; the second mixed slurry flowing out of the second headbox is formed through the fourdrinier wire section 109 to prepare a surface wet paper layer on the interface layer to obtain a wet paper sheet; the wet paper sheet is sequentially passed through the pressing section 110 for pressing and dehydration, and passed through the pre-drying section 111 for a drying treatment to obtain a paper sheet to be sizing.

[0068] Step 4: Surface sizing treatment: The paper sheet to be sizing is subjected to surface sizing treatment after entering the surface sizing machine 112 to obtain sizing paper sheet. In the surface sizing treatment process, a compound composed of enzymatic starch, water repellent and cationic polyacrylamide in a mass ratio of 100:12-15:0.1-0.2 is used as the surface sizing agent, and the sizing amount is controlled to be 10-12 g / m2 on both sides. 2 The solid content of the surface sizing agent is 28% to 30%, and the viscosity is 40 to 45 mPa·s.

[0069] Process 5: Secondary drying, calendering and coiling:

[0070] The sizing paper sheet is subjected to secondary drying treatment in the post-drying section 113, and then subjected to calendering treatment in the calendering machine 114, the pressure of the calendering treatment being controlled at 80-150 kN / m, and finally subjected to winding treatment in the paper reel 115 to obtain finished paper.

[0071] The present application has been subjected to multiple tests, and part of the test results are now cited as references to further describe the invention in detail, which is described in detail below in conjunction with specific embodiments.

[0072] Example 1

[0073] See also Figure 1 and Figure 3 The preparation method of the dictionary paper provided in this embodiment is as follows:

[0074] Process 1: Slurry preparation:

[0075] The beaten softwood pulp, hardwood pulp, dry damaged pulp, and wet damaged pulp are mixed and screened in a mass ratio of 40:60:5:5 to obtain a first screened slurry and a second screened slurry. Then, the first screened slurry is transported to the first slurry preparation tank of the slurry preparation tank 101, and the second screened slurry is transported to the second slurry preparation tank of the slurry preparation tank 101. A composite filler (a composite of porous calcium silicate with an average particle size of 18 μm and kaolin with an average particle size of 2 μm in a mass ratio of 1:6) is added to the first slurry preparation tank. The mass ratio of the first screened slurry to the composite filler is 10:1 to obtain a first mixed slurry, which is then transported to the first slurry preparation tank of the slurry preparation tank 102. A composite filler (a compound of porous calcium silicate with an average particle size of 18 μm and kaolin with an average particle size of 2 μm in a mass ratio of 1:6) is added into the second slurry preparation tank. The mass ratio of the second screened slurry to the composite filler is 10:1. A second mixed slurry is obtained and transported to the second slurry preparation tank 102.

[0076] Process 2: Slurry preparation:

[0077] The first mixed slurry in the first stock tank is transported to the first stock mixing box of the stock mixing box 103 for adjustment, and then enters the first stock tank of the stock washing tank 104, and then the impeller of the first stock pump in the stock washing pump 105 rotates at high speed, so that the first mixed slurry is fully mixed with the concentrated white water, and then enters the first deslagging system of the deslagging system 106, and a small amount of white water is added at the same time, and then passes through the first pressure screen (in-flow pressure screen) of the pressure screen 107, and then enters the first headbox of the headbox 108. The second mixed slurry in the second stock tank is transported to the second stock mixing box of the stock mixing box 103 for adjustment, and then enters the second stock washing tank of the stock washing tank 104, and then the impeller of the second stock pump in the stock washing pump 105 rotates at high speed, so that the second mixed slurry is fully mixed with the concentrated white water, and then enters the second deslagging system of the deslagging system 106, and a small amount of white water is added at the same time, and then passes through the second pressure screen (in-flow pressure screen) of the pressure screen 107, and then enters the second headbox of the headbox 108.

[0078] Process 3: Forming, pressing and primary drying:

[0079] The first mixed slurry flowing out of the first headbox is formed through the fourdrinier wire section 109 to obtain a bottom wet paper layer; an interface layer is prepared on the bottom wet paper layer using an interface agent (a composition of nanocellulose, sodium carboxymethyl cellulose and polyvinyl alcohol in a mass ratio of 0.8:2:1); the second mixed slurry flowing out of the second headbox is formed through the fourdrinier wire section 109 to prepare a surface wet paper layer on the interface layer to obtain a wet paper sheet; the wet paper sheet is sequentially passed through the pressing section 110 for pressing and dehydration, and passed through the pre-drying section 111 for a drying treatment to obtain a paper sheet to be sizing.

[0080] Step 4: Surface sizing treatment: The paper sheet to be sizing is subjected to surface sizing treatment after entering the surface sizing machine 112 to obtain sizing paper sheet. In the surface sizing treatment process, a compound composed of enzymatic starch, water repellent and cationic polyacrylamide in a mass ratio of 100:12:0.1 is used as the surface sizing agent, and the sizing amount is controlled to be 10 g / m2 on both sides. 2 The solid content of the surface sizing agent is 28% and the viscosity is 40mPa·s.

[0081] Process 5: Secondary drying, calendering and coiling:

[0082] The sizing paper sheet is subjected to secondary drying treatment in the post-drying section 113, and then subjected to calendering treatment in the calendering machine 114, the pressure of the calendering treatment being controlled at 80 kN / m, and finally subjected to winding treatment in the paper reel 115 to obtain finished paper.

[0083] Example 2

[0084] See also Figure 1 and Figure 3 The preparation method of the dictionary paper provided in this embodiment is as follows:

[0085] Process 1: Slurry preparation:

[0086] The beaten softwood pulp, hardwood pulp, dry damaged pulp, and wet damaged pulp are mixed and screened in a mass ratio of 45:55:10:0 to obtain a first screened slurry and a second screened slurry. Then, the first screened slurry is transported to the first slurry preparation tank of the slurry preparation tank 101, and the second screened slurry is transported to the second slurry preparation tank of the slurry preparation tank 101. A composite filler (a composite of porous calcium silicate with an average particle size of 22 μm and kaolin with an average particle size of 2 μm in a mass ratio of 4:6) is added to the first slurry preparation tank. The mass ratio of the first screened slurry to the composite filler is 10:2 to obtain a first mixed slurry, which is transported to the first slurry preparation tank of the slurry preparation tank 102. A composite filler (a compound of porous calcium silicate with an average particle size of 22 μm and kaolin with an average particle size of 2 μm in a mass ratio of 4:6) is added into the second slurry preparation tank. The mass ratio of the second screened slurry to the composite filler is 10:1. A second mixed slurry is obtained and transported to the second slurry preparation tank 102.

[0087] Process 2: Slurry preparation:

[0088] The first mixed slurry in the first stock tank is transported to the first stock mixing box of the stock mixing box 103 for adjustment, and then enters the first stock tank of the stock washing tank 104, and then the impeller of the first stock pump in the stock washing pump 105 rotates at high speed, so that the first mixed slurry is fully mixed with the concentrated white water, and then enters the first deslagging system of the deslagging system 106, and a small amount of white water is added at the same time, and then passes through the first pressure screen (in-flow pressure screen) of the pressure screen 107, and then enters the first headbox of the headbox 108. The second mixed slurry in the second stock tank is transported to the second stock mixing box of the stock mixing box 103 for adjustment, and then enters the second stock washing tank of the stock washing tank 104, and then the impeller of the second stock pump in the stock washing pump 105 rotates at high speed, so that the second mixed slurry is fully mixed with the concentrated white water, and then enters the second deslagging system of the deslagging system 106, and a small amount of white water is added at the same time, and then passes through the second pressure screen (in-flow pressure screen) of the pressure screen 107, and then enters the second headbox of the headbox 108.

[0089] Process 3: Forming, pressing and primary drying:

[0090] The first mixed slurry flowing out of the first headbox is formed through the fourdrinier wire section 109 to obtain a bottom wet paper layer; an interface layer is prepared on the bottom wet paper layer using an interface agent (a composition of nanocellulose, sodium carboxymethyl cellulose and polyvinyl alcohol in a mass ratio of 0.8:1:2); the second mixed slurry flowing out of the second headbox is formed through the fourdrinier wire section 109 to prepare a surface wet paper layer on the interface layer to obtain a wet paper sheet; the wet paper sheet is sequentially passed through the pressing section 110 for pressing and dehydration, and passed through the pre-drying section 111 for a drying treatment to obtain a paper sheet to be sizing.

[0091] Step 4: Surface sizing treatment: The paper sheet to be sizing is subjected to surface sizing treatment after entering the surface sizing machine 112 to obtain sizing paper sheet. In the surface sizing treatment process, a compound composed of enzymatic starch, water repellent and cationic polyacrylamide in a mass ratio of 100:12:0.1 is used as the surface sizing agent, and the sizing amount is controlled to be 15 g / m2 on both sides. 2 The solid content of the surface sizing agent is 30% and the viscosity is 45mPa·s.

[0092] Process 5: Secondary drying, calendering and coiling:

[0093] The sizing paper sheet is subjected to secondary drying treatment in the post-drying section 113, and then subjected to calendering treatment in the calendering machine 114, the pressure of the calendering treatment being controlled at 100 kN / m, and finally subjected to winding treatment in the paper reel 115 to obtain finished paper.

[0094] Example 3

[0095] See also Figure 1 and Figure 3 The preparation method of the dictionary paper provided in this embodiment is as follows:

[0096] Process 1: Slurry preparation:

[0097] The beaten softwood pulp, hardwood pulp, dry damaged pulp and wet damaged pulp are mixed and screened in a mass ratio of 40:60:10:10 to obtain a first screened slurry and a second screened slurry. Then, the first screened slurry is transported to the first slurry preparation tank of the slurry preparation tank 101, and the second screened slurry is transported to the second slurry preparation tank of the slurry preparation tank 101. A composite filler (a composite of porous calcium silicate with an average particle size of 21 μm and kaolin with an average particle size of 2 μm in a mass ratio of 4:6) is added to the first slurry preparation tank. The mass ratio of the first screened slurry to the composite filler is 10:2 to obtain a first mixed slurry, which is then transported to the first slurry preparation tank of the slurry preparation tank 102. A composite filler (a compound of porous calcium silicate with an average particle size of 21 μm and kaolin with an average particle size of 2 μm in a mass ratio of 4:6) is added into the second slurry preparation tank. The mass ratio of the second screened slurry to the composite filler is 10:2 to obtain a second mixed slurry, which is transported to the second slurry preparation tank 102.

[0098] Process 2: Slurry preparation:

[0099] The first mixed slurry in the first stock tank is transported to the first stock mixing box of the stock mixing box 103 for adjustment, and then enters the first stock tank of the stock washing tank 104, and then the impeller of the first stock pump in the stock washing pump 105 rotates at high speed, so that the first mixed slurry is fully mixed with the concentrated white water, and then enters the first deslagging system of the deslagging system 106, and a small amount of white water is added at the same time, and then passes through the first pressure screen (in-flow pressure screen) of the pressure screen 107, and then enters the first headbox of the headbox 108. The second mixed slurry in the second stock tank is transported to the second stock mixing box of the stock mixing box 103 for adjustment, and then enters the second stock washing tank of the stock washing tank 104, and then the impeller of the second stock pump in the stock washing pump 105 rotates at high speed, so that the second mixed slurry is fully mixed with the concentrated white water, and then enters the second deslagging system of the deslagging system 106, and a small amount of white water is added at the same time, and then passes through the second pressure screen (in-flow pressure screen) of the pressure screen 107, and then enters the second headbox of the headbox 108.

[0100] Process 3: Forming, pressing and primary drying:

[0101] The first mixed slurry flowing out of the first headbox is formed through the fourdrinier wire section 109 to obtain a bottom wet paper layer; an interface layer is prepared on the bottom wet paper layer using an interface agent (a composition of nanocellulose, sodium carboxymethyl cellulose and polyvinyl alcohol in a mass ratio of 0.8:1:2); the second mixed slurry flowing out of the second headbox is formed through the fourdrinier wire section 109 to prepare a surface wet paper layer on the interface layer to obtain a wet paper sheet; the wet paper sheet is sequentially passed through the pressing section 110 for pressing and dehydration, and passed through the pre-drying section 111 for a drying treatment to obtain a paper sheet to be sizing.

[0102] Step 4: Surface sizing treatment: The paper sheet to be sizing is subjected to surface sizing treatment after entering the surface sizing machine 112 to obtain sizing paper sheet. In the surface sizing treatment process, a compound composed of enzymatic starch, water repellent and cationic polyacrylamide in a mass ratio of 100:15:0.1 is used as the surface sizing agent, and the sizing amount is controlled to be 12 g / m2 on both sides. 2 The solid content of the surface sizing agent is 30% and the viscosity is 45mPa·s.

[0103] Process 5: Secondary drying, calendering and coiling:

[0104] The sizing paper sheet is subjected to secondary drying treatment in the post-drying section 113, and then subjected to calendering treatment in the calendering machine 114, the pressure of the calendering treatment being controlled at 80 kN / m, and finally subjected to winding treatment in the paper reel 115 to obtain finished paper.

[0105] Example 4

[0106] See also Figure 1 and Figure 3The preparation method of the dictionary paper provided in this embodiment is as follows:

[0107] Process 1: Slurry preparation:

[0108] The beaten softwood pulp, hardwood pulp, dry damaged pulp, and wet damaged pulp are mixed and screened in a mass ratio of 50:70:0:10 to obtain a first screened slurry and a second screened slurry. Then, the first screened slurry is transported to the first slurry preparation tank of the slurry preparation tank 101, and the second screened slurry is transported to the second slurry preparation tank of the slurry preparation tank 101. A composite filler (a composite of porous calcium silicate with an average particle size of 21 μm and kaolin with an average particle size of 2 μm in a mass ratio of 4:6) is added to the first slurry preparation tank. The mass ratio of the first screened slurry to the composite filler is 10:2 to obtain a first mixed slurry, which is then transported to the first slurry preparation tank of the slurry preparation tank 102. A composite filler (a compound of porous calcium silicate with an average particle size of 21 μm and kaolin with an average particle size of 2 μm in a mass ratio of 4:6) is added into the second slurry preparation tank. The mass ratio of the second screened slurry to the composite filler is 10:2 to obtain a second mixed slurry, which is transported to the second slurry preparation tank 102.

[0109] Process 2: Slurry preparation:

[0110] The first mixed slurry in the first stock tank is transported to the first stock mixing box of the stock mixing box 103 for adjustment, and then enters the first stock tank of the stock washing tank 104, and then the impeller of the first stock pump in the stock washing pump 105 rotates at high speed, so that the first mixed slurry is fully mixed with the concentrated white water, and then enters the first deslagging system of the deslagging system 106, and a small amount of white water is added at the same time, and then passes through the first pressure screen (in-flow pressure screen) of the pressure screen 107, and then enters the first headbox of the headbox 108. The second mixed slurry in the second stock tank is transported to the second stock mixing box of the stock mixing box 103 for adjustment, and then enters the second stock washing tank of the stock washing tank 104, and then the impeller of the second stock pump in the stock washing pump 105 rotates at high speed, so that the second mixed slurry is fully mixed with the concentrated white water, and then enters the second deslagging system of the deslagging system 106, and a small amount of white water is added at the same time, and then passes through the second pressure screen (in-flow pressure screen) of the pressure screen 107, and then enters the second headbox of the headbox 108.

[0111] Process 3: Forming, pressing and primary drying:

[0112] The first mixed slurry flowing out of the first headbox is formed through the fourdrinier wire section 109 to obtain a bottom wet paper layer; an interface layer is prepared on the bottom wet paper layer using an interface agent (a composition of nanocellulose, sodium carboxymethyl cellulose and polyvinyl alcohol in a mass ratio of 1:1:3); the second mixed slurry flowing out of the second headbox is formed through the fourdrinier wire section 109 to prepare a surface wet paper layer on the interface layer to obtain a wet paper sheet; the wet paper sheet is sequentially passed through the pressing section 110 for pressing and dehydration, and passed through the pre-drying section 111 for a drying treatment to obtain a paper sheet to be sizing.

[0113] Step 4: Surface sizing treatment: The paper sheet to be sizing is subjected to surface sizing treatment after entering the surface sizing machine 112 to obtain sizing paper sheet. In the surface sizing treatment process, a compound composed of enzymatic starch, water repellent and cationic polyacrylamide in a mass ratio of 100:15:0.2 is used as the surface sizing agent, and the sizing amount is controlled to be 11 g / m2 on both sides. 2 The solid content of the surface sizing agent is 30% and the viscosity is 45mPa·s.

[0114] Process 5: Secondary drying, calendering and coiling:

[0115] The sizing paper sheet is subjected to secondary drying treatment in the post-drying section 113, and then subjected to calendering treatment in the calendering machine 114, the pressure of the calendering treatment being controlled at 150 kN / m, and finally subjected to winding treatment in the paper reel 115 to obtain finished paper.

[0116] Comparative Example 1

[0117] This comparative example provides a dictionary paper, and its preparation method is basically the same as that of the above-mentioned Example 3, except that: the process 1 is replaced by: the beaten coniferous wood pulp, hardwood pulp, dry damaged pulp, and wet damaged pulp are mixed and screened in a mass ratio of 40:60:10:10 to obtain a first screened slurry and a second screened slurry, and then the first screened slurry is transported to the first stock tank of the stock tank 101, and the second screened slurry is transported to the second stock tank of the stock tank 101. Filler (kaolin with an average particle size of 2 μm) is added to the first stock tank, and the mass ratio of the first screened slurry to the filler is 10:2 to obtain a first mixed slurry, which is then transported to the first stock tank of the stock tank 102. Filler (kaolin with an average particle size of 2 μm) is added to the second stock tank, and the mass ratio of the second screened slurry to the composite filler is 10:2 to obtain a second mixed slurry, which is then transported to the second stock tank of the stock tank 102.

[0118] Comparative Example 2

[0119] This comparative example provides a dictionary paper, and its preparation method is basically the same as that of the above-mentioned Example 3, and the only difference is that: the process 1 is replaced by: the beaten softwood pulp, hardwood pulp, dry damaged pulp and wet damaged pulp are mixed and screened in a mass ratio of 40:60:10:10 to obtain a first screened pulp and a second screened pulp, and then the first screened pulp is transported to the first stock preparation tank of the stock preparation tank 101, and the second screened pulp is transported to the second stock preparation tank of the stock preparation tank 101. Filler (porous calcium silicate with an average particle size of 21 μm) is added to the first stock preparation tank, and the mass ratio of the first screened pulp to the composite filler is 10:2 to obtain a first mixed pulp, and it is transported to the first stock preparation tank of the stock preparation tank 102. A composite filler (porous calcium silicate with an average particle size of 21 μm) is added into the second slurry preparation tank. The mass ratio of the second screened slurry to the composite filler is 10:2 to obtain a second mixed slurry, which is transported to the second slurry preparation tank of the slurry preparation tank 102.

[0120] Comparative Example 3

[0121] This comparative example provides a dictionary paper, and its preparation method is basically the same as that of the above-mentioned Example 3, and the only difference is that: step three is replaced by: the first mixed slurry flowing out of the first headbox is formed by the fourdrinier section 109 to obtain a bottom wet paper layer; the second mixed slurry flowing out of the second headbox is formed by the fourdrinier section 109 to prepare a surface wet paper layer on the bottom wet paper layer to obtain a wet paper sheet; the wet paper sheet is successively passed through the pressing section 110 for pressing and dehydration, and passed through the pre-drying section 111 for a drying treatment to obtain a paper sheet to be sizing.

[0122] Comparative Example 4

[0123] This comparative example provides a dictionary paper, and its preparation method is basically the same as that of the above-mentioned embodiment 3, and the only difference is that: the fourth step is replaced by: the paper sheet to be sized entering the surface sizing machine 112 is subjected to surface sizing treatment to obtain a sized paper sheet. In the surface sizing process, a compound composed of enzymatic starch and cationic polyacrylamide in a mass ratio of 100:0.1 is used as a surface sizing agent, and the sizing amount is controlled to be 12g / m2 on both sides. 2 The solid content of the surface sizing agent is 30% and the viscosity is 45mPa·s.

[0124] Comparative Example 5

[0125] This comparative example provides a dictionary paper, and its preparation method is as follows:

[0126] Step 1, pulping: the beaten softwood pulp, hardwood pulp, dry damaged pulp and wet damaged pulp are mixed in a mass ratio of 40:60:10:10 to obtain a pulping mixed pulp; then, the mixed pulp is transported to the pulping tank 101. A composite filler (a composite of porous calcium silicate with an average particle size of 21 μm and kaolin with an average particle size of 2 μm in a mass ratio of 4:6) is added to the pulping tank 101, and the mass ratio of the mixed pulp to the composite filler is 10:2 to obtain a filled mixed pulp, which is then transported to the pulping tank 102.

[0127] Process 2: Slurry preparation:

[0128] The added mixed slurry in the slurry pool 102 is transported to the slurry mixing box 103 for adjustment and then enters the slurry flushing pool 104. The impeller of the slurry flushing pump 105 rotates at high speed to fully mix the added mixed slurry with the concentrated white water. The slurry then enters the slag removal system 106, and a small amount of white water is added at the same time. The slurry then passes through the pressure screen 107 and enters the headbox 108.

[0129] Process 3: Forming, pressing and primary drying:

[0130] The added mixed slurry flowing out from the headbox 108 is formed into a paper by the fourdrinier section 109 to obtain a wet paper sheet; the wet paper sheet is successively passed through the pressing section 110 for pressing and dehydration, and passed through the pre-drying section 111 for a drying treatment to obtain a paper sheet to be sizing.

[0131] Step 4: Surface sizing treatment: The paper sheet to be sizing is subjected to surface sizing treatment after entering the surface sizing machine 112 to obtain sizing paper sheet. In the surface sizing treatment process, a compound composed of enzymatic starch, water repellent and cationic polyacrylamide in a mass ratio of 100:15:0.1 is used as the surface sizing agent, and the sizing amount is controlled to be 12 g / m2 on both sides. 2 The solid content of the surface sizing agent is 30% and the viscosity is 45mPa·s.

[0132] Process 5: Secondary drying, calendering and coiling:

[0133] The sizing paper sheet is subjected to secondary drying treatment in the post-drying section 113, and then subjected to calendering treatment in the calendering machine 114, the pressure of the calendering treatment being controlled at 80 kN / m, and finally subjected to winding treatment in the paper reel 115 to obtain finished paper.

[0134] The dictionary papers prepared in the above-mentioned Examples 1 to 4 and Comparative Examples 1 to 5 were tested for the following performance indicators, the test items are shown in Table 1, and the test results are shown in Table 2 and Table 3. Various physical and chemical indicators were tested in accordance with relevant national standards.

[0135] Table 1

[0136]

[0137] Table 2

[0138] Test items Example 1 Example 2 Example 3 Example 4 <![CDATA[Quantitative (g / m 2 )]]> 50.3 50.2 50.1 50.5 Transverse folding endurance (times) 15 12 20 13 Longitudinal tensile index (N·m / g) 40.3 42.7 45.5 41.2 Whiteness(%) 82.0 81.4 81.7 80.9 Opacity (%) 91.5 90.7 94.2 92.3 Smoothness (s, both front and back) 50.1 51.0 52.3 51.6 Smoothness (%, front and back difference) 13.4 14.6 10.3 11.8 Printing surface strength (m / s, both front and back sides) 2.1 1.8 2.7 1.6

[0139] Table 3

[0140]

[0141]

[0142] It can be seen from Tables 1 to 3 that the various indicators of the dictionary paper prepared in Examples 1 to 4 of the present application can meet the indicator requirements of high-quality products, the paper quality is good, has good strength and tear resistance, and high opacity.

[0143] Generally speaking, the longitudinal tensile index of paper is proportional to the tear resistance of the paper, that is, the larger the longitudinal tensile index, the better the tear resistance; conversely, the smaller the longitudinal tensile index, the worse the tear resistance.

[0144] From the comparison results of Example 3 and Comparative Examples 1-2, it can be seen that compared with Comparative Examples 1-2 which only use porous calcium silicate or kaolin as fillers, Example 3 of the present application adds a composition composed of porous calcium silicate and kaolin as a composite filler, and the longitudinal tensile index of the dictionary paper prepared is increased by about 27% to 29%, and the opacity is increased by about 19% to 20%. It can be seen that compounding porous calcium silicate and kaolin and using them as papermaking fillers is conducive to improving the tear resistance and opacity of paper.

[0145] From the comparison results of Example 3 and Comparative Example 3, it can be seen that compared with Comparative Example 3 in which the water repellent in the surface sizing agent is omitted, Example 3 of the present application adds a water repellent to the surface sizing agent, and the printing surface strength of the paper prepared is increased from 1.0 m / s to 2.7 m / s, which is increased by 1.7 times. It can be seen that adding a water repellent to the surface sizing agent is beneficial to improving the printing surface strength of the paper.

[0146] From the comparison results of Example 3 and Comparative Example 4, it can be seen that compared with the dictionary paper prepared by omitting the interface layer in Comparative Example 4, the transverse folding endurance of the dictionary paper prepared in Example 3 increased by 12 times, the longitudinal tensile index increased by about 27%, the opacity increased by about 20%, and the printing surface strength increased by 2 times. It can be seen that by preparing an interface layer between the bottom wet paper layer and the surface wet paper layer, it is beneficial to improve the transverse folding endurance, longitudinal tensile index, opacity and printing surface strength of the paper.

[0147] From the comparison results of Example 3 and Comparative Example 5, it can be seen that compared with the single-layer dictionary paper prepared in Comparative Example 5, the transverse folding resistance of the double-layer dictionary paper prepared in Example 3 of the present application has increased by 17 times, the longitudinal tensile index has increased from 31.4N·m / g to 45.5N·m / g, an increase of about 45%, the opacity has increased from 77.1% to 94.2%, an increase of about 22%, and the printing surface strength has increased from 0.9m / s to 2.7m / s, an increase of 2 times. It can be seen that the double-layer dictionary paper prepared in the embodiment of the present application has the advantages of excellent paper strength, tear resistance, and high opacity.

[0148] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for preparing dictionary paper, characterized in that: include: Mixing and screening coniferous wood pulp, hardwood wood pulp, dry damaged pulp and wet damaged pulp in a mass ratio of 40-50:60-70:0-10:0-10 to obtain a first screened pulp and a second screened pulp, wherein the average fiber length of the first screened pulp is 0.78-0.88 mm, and the average fiber length of the second screened pulp is 0.90-0.98 mm; The first screened slurry is mixed with a composite filler to obtain a first mixed slurry, and the second screened slurry is mixed with a composite filler to obtain a second mixed slurry; wherein the composite filler is porous calcium silicate and kaolin; Using the first mixed slurry to prepare a bottom wet paper layer, using an interface agent to prepare an interface layer on the bottom wet paper layer, and using the second mixed slurry to prepare a surface wet paper layer on the interface layer to obtain a wet paper sheet; Performing a drying process on the wet paper sheet to obtain a paper sheet to be sized; The paper sheet to be sized is subjected to surface sizing treatment to obtain a sized paper sheet; wherein the surface sizing agent used in the surface sizing treatment includes enzymatic starch, water repellent and cationic polyacrylamide; the double-sided sizing amount of the surface sizing agent is 10-12 g / m 2 ; The sized paper sheet is subjected to secondary drying and calendering to obtain a paper sheet with a basis weight of 40 to 50 g / m 2 Dictionary paper.

2. The method for preparing dictionary paper according to claim 1, characterized in that: The mass ratio of the first screening slurry to the composite filler is 10:1-3; The mass ratio of the second screening slurry to the composite filler is 10:1-2; The mass ratio of porous calcium silicate to kaolin in the composite filler is 1 to 4:

6.

3. The method for preparing dictionary paper according to claim 1 or 2, characterized in that: The average particle size of the porous calcium silicate is 18-22 μm; the average particle size of the kaolin is 1-2 μm.

4. The method for preparing dictionary paper according to claim 1, characterized in that: The interface agent includes at least two of nanocellulose, sodium carboxymethyl cellulose and polyvinyl alcohol.

5. The method for preparing dictionary paper according to claim 4, characterized in that: The interface agent includes nanocellulose, sodium carboxymethyl cellulose and polyvinyl alcohol; The mass ratio of the nanocellulose, sodium carboxymethyl cellulose and polyvinyl alcohol is 0.8-1:1-2:1-3.

6. The method for preparing dictionary paper according to claim 1, characterized in that: The preparation steps of the enzymatic starch are as follows: Cassava starch or corn starch is used as a starting material, and alpha-amylase is used to perform enzymatic degradation on the starting material to obtain enzymatic starch with a viscosity of 40 to 45 mPa·s; wherein the use concentration of the alpha-amylase is 0.08 mL / kg of the starting material.

7. The method for preparing dictionary paper according to claim 1, characterized in that: The water repellent is modified melamine formaldehyde resin.

8. The method for preparing dictionary paper according to claim 1, characterized in that: The mass ratio of the enzymatic starch, the water repellent and the cationic polyacrylamide in the surface sizing agent is 100:12-15:0.1-0.

2.

9. The method for preparing dictionary paper according to claim 1, characterized in that: The pressure of the calendering treatment is 80 to 150 kN / m.

10. A dictionary paper, characterized in that: The dictionary paper is prepared according to the method for preparing dictionary paper according to any one of claims 1 to 9.

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