Super-sensitive paper and preparation method thereof

Abstract

The invention provides super-sensitive paper and a preparation method thereof. The preparation method comprises the following steps: making raw paper; wherein the raw paper comprises a surface layer, a surface lining layer, a core layer and a bottom layer which are sequentially stacked; each layer of paper pulp comprises a whitening agent and a dye; and coating the front and back surfaces of the raw paper for one time. The super-sensitive paper obtained by utilizing the preparation method of the super-sensitive paper has the characteristics of high opacity, low glossiness, high printing color saturation, strong paper texture feeling, good texture and the like, has unique visual and touch effects, has the characteristics of roughness, thickness and obvious texture in the aspect of touch feeling, and has the characteristics of good color and luster in the aspect of vision. The product is low in glossiness, can present unique color and grain effects after being printed, enables people to feel distinctive texture and quality value of printed matters, and can be applied to the fields of high-end brands, cover design, brochure, business cards and the like, and in addition, the preparation method also has the characteristics of simple process and low cost.

Description

Technical Field

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

[0002] As market competition becomes increasingly fierce and people's living standards improve, the requirements for paper products are getting higher and higher. At present, the conventional white card and coated card paper on the market have the characteristics of high gloss, high paper smoothness, and poor printing ink absorption. At the same time, in order to meet the surface flatness of copper card and white card paper, the paper surface uses three coatings, which makes the natural texture and texture of the paper itself no longer exist, resulting in a significant reduction in the visual effect and touch of the paper after printing, which cannot meet the needs of customers such as high-end picture albums and art books. Summary of the invention

[0003] A first aspect of the present application provides a method for preparing supersensitive paper, the method comprising:

[0004] Papermaking base paper; wherein the base paper comprises a surface layer, a surface lining layer, a core layer and a bottom layer which are stacked in sequence; the pulp of each layer comprises a whitening agent and a dye;

[0005] A coating is performed on both the front and back sides of the base paper.

[0006] In some optional embodiments, the pulp of the surface layer, the surface lining layer and the bottom layer all include: 15±5% coniferous pulp and 85±10% broadleaf pulp; the pulp of the core layer includes: 10±5% coniferous pulp, 50±10% broadleaf pulp, 35±10% chemical-mechanical pulp and 5±5% damaged pulp.

[0007] In some optional embodiments, the whitening agent in the pulp of the surface layer, the surface lining layer and the bottom layer is tetrasulfonic acid, and the added amount of the tetrasulfonic acid is 0.7%±0.1% of the absolute dry pulp of the pulp.

[0008] In some optional embodiments, the whitening agent in the pulp of the core layer is disulfonic acid, and the added amount of the disulfonic acid is 0.7%±0.2% of the absolute dry pulp of the pulp.

[0009] In some optional embodiments, the pulp of the surface layer, the surface lining layer, the bottom layer and the core layer all include a polyacrylamide-based retention aid, the molecular weight of the retention aid is above 8 million, and the addition amount is 250±50 ppm.

[0010] In some optional embodiments, the pulp of the core layer further includes a polyacrylamide dry strength agent, and the added amount is 1.0±0.5%.

[0011] In some optional embodiments, in the step of coating both the front and back sides of the base paper, the coating amount is 12.0±0.5 gsm.

[0012] In some optional embodiments, in the step of coating both sides of the base paper, the coatings coated on both sides include: 20±10% GCC93, 60±10% GCC50, 20±10% PCC, 12±2% latex and 2±1% matting powder.

[0013] In some optional embodiments, the latex is butadiene-styrene, and the glass transition temperature of the latex is -3 to -10°C; the particle size D50 of the matting powder is 4±2 um.

[0014] In a second aspect, an embodiment of the present application provides a super-sensitive paper, which is prepared by the preparation method described in the above embodiment.

[0015] The preparation method of super-sensitive paper provided in the embodiment of the present application, the super-sensitive paper obtained by the method has the characteristics of high opacity, low glossiness, high printing color saturation, strong paper texture, good texture, etc. The super-sensitive paper has unique visual and tactile effects. In terms of touch, it has the characteristics of being rough, thick, and having obvious texture. In terms of vision, the product has low glossiness and can present unique color and texture effects after printing, which makes people feel the unique printing quality and quality value. It can be applied to high-end brands, art exhibitions, cover design, brochures, business cards and other fields. In addition, the preparation method is also characterized by simple process and low cost. 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 description of the embodiments 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 creative work.

[0017] Figure 1 It is a schematic flow chart of an embodiment of a method for preparing super-sensitive paper of the present application;

[0018] Figure 2 It is a schematic diagram of the cross-sectional structure of an embodiment of the super-sensitive paper of the present application. DETAILED DESCRIPTION

[0019] The present application is further described in detail below in conjunction with the accompanying drawings and examples. It is particularly noted that the following examples are only used to illustrate the present application, but are not intended to limit the scope of the present application. Similarly, the following examples are only some embodiments of the present application rather than all embodiments, and all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0020] The terms "first", "second", and "third" in the embodiments of the present application are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first", "second", and "third" can expressly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the embodiments of the present application, all directional indications (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly. The terms "including" and "having" in the embodiments of the present application and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or components inherent to these processes, methods, products, or devices.

[0021] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0022] See also Figure 1 , Figure 1 1 is a flow chart of an embodiment of a method for preparing supersensitive paper of the present application, and the preparation method includes but is not limited to the following steps.

[0023] Step S100, making base paper.

[0024] Please also read Figure 2 , Figure 2: is a schematic diagram of the cross-sectional structure of an embodiment of the supersensitive paper of the present application, wherein the base paper in this embodiment comprises a surface layer 110, a surface lining layer 120, a core layer 130 and a bottom layer 140 stacked in sequence. Optionally, the base paper adopts a four-layer paper sheet online compounding technology, and the quantitative design of each layer is: surface layer (18±1gsm) + surface lining layer (18±1gsm) + core layer (120±3gsm) + bottom layer (36±1gsm), and the pulp of each layer includes a whitening agent and a dye.

[0025] Optionally, the pulp of the surface layer 110, the surface lining layer 120 and the bottom layer 140 in the embodiment of the present application all include: 15±5% coniferous pulp and 85±10% hardwood pulp, and the whitening agent is tetrasulfonic acid. For the absolute dry pulp, the addition amount of tetrasulfonic acid is 0.7%±0.1%, and the specific addition amount of tetrasulfonic acid can be 0.6%, 0.62%, 0.65%, 0.68%, 0.7%, 0.75%, 0.8% and other values ​​of the absolute dry pulp. The retention agent of polyacrylamide (molecular weight above 8 million) is added at 250±50ppm, and the specific value can be 200ppm, 210ppm, 240ppm, 250ppm, 265ppm, 280ppm, 290ppm, 300ppm and other values.

[0026] The pulp of the core layer 130 may include: 10±5% coniferous pulp, 50±10% hardwood pulp, 35±10% chemical mechanical pulp and 5±5% damaged pulp. The whitening agent is disulfonic acid, and the addition amount is 0.7±0.2%. The addition amount of disulfonic acid can be 0.5%, 0.52%, 0.6%, 0.68%, 0.7%, 0.75%, 0.8%, 0.9% and other values ​​of the absolute dry pulp. The retention agent of polyacrylamide (PAM) (molecular weight above 8 million) is added at 250±50ppm, and the addition amount of polyacrylamide dry strength agent (molecular weight above 2 million) is 1.0±0.5%.

[0027] Optionally, the dyes in the pulp of the surface layer 110, the surface lining layer 120, the core layer 130 and the bottom layer 140 can be alkaline red and purple dyes, wherein the red dye is added in an amount of 10±3ppm and the purple dye is added in an amount of 12±5ppm.

[0028] The super-sensitive paper in the embodiment of the present application has the characteristics of high opacity, high printing color saturation, strong paper texture and good texture. In view of the above characteristics, the base paper pulp is specially designed. First, the freeness of the pulp used is set as follows: 450±20ml for coniferous wood, 400±20ml for hardwood, 400±20ml for chemical mechanical pulp, and 280±20ml for damaged paper pulp. Because the lower the freeness of the pulp, the higher the degree of beating, the higher the degree of fiber fibrillation, resulting in the fiber surface fibrillation and fluffing, like fluff attached to the fiber surface, the fine fiberization of the surface, a large amount of fine fiber agent and microfiber can be separated, resulting in the formation of the fiber web, the fine fibers can effectively fill the pores between the fibers and the fibers, improve the pulp strength, and increase the flatness of the base paper surface. The base paper cannot reflect the texture of the fiber itself. And the higher the freeness, the fiber has no obvious fibrillation, which will reduce the pulp strength. Therefore, the pulps of the present invention use the above freeness to ensure the strength of the paper while the base paper exhibits a clear texture.

[0029] Please continue reading Figure 1 The method for preparing super-sensitive paper in the embodiment of the present application further includes step S200, in which a coating is performed on both the front and back sides of the base paper.

[0030] Please continue reading Figure 2 , Figure 2 Reference numeral 210 indicates a top coating layer, and reference numeral 220 indicates a bottom coating layer.

[0031] Coating amount: Both the top and bottom layers are coated in one layer, with a coating amount of 12.0±0.5gsm; avoid too much coating covering the paper surface, which will cause the fiber texture of the base paper to be covered and fail to reflect the roughness and texture of the product. Cancel soft calendering to reduce the glossiness of the paper.

[0032] The coating formula for the top and bottom layers: 20±10% GCC93 (ground calcium carbonate) + (60±10%) GCC50 + (20±10%) PCC (precipitated calcium carbonate) + (12±2%) SB latex (butadiene-styrene) + (2±1%) matting powder. Compared with GCC, PCC is spindle-shaped due to different production processes, with a narrow particle size distribution of 0.4-3.0μm and a higher light refractive index than GCC. Therefore, the use of PCC can improve the whiteness and opacity of coated paper. At the same time, large-particle PCC and GCC are used in a certain proportion to balance the coating with lower gloss and better ink absorption. The Tg (glass transition temperature) of SB latex is controlled at -3 to -10℃. The film-forming property of the latex with a lower Tg is quite soft, so that the coated paper surface has a low gloss and a high printing gloss. The main component of matting powder is wax-treated precipitated silica, and its particle size D50 is 4±2um. Silica has a high refractive index and transmittance. When light passes through silica particles, it will be refracted and reflected multiple times, resulting in a multiple scattering effect. This multiple scattering will cause the light to change direction multiple times when it propagates in the material, thereby reducing the transmittance of the light and achieving the effect of matting. At the same time, the particle size D50 of silica particles is 4±2um, and its particle size is relatively fine, which makes them have diffraction characteristics. When light passes through silica particles, diffraction occurs, and the light is scattered at different angles. This diffraction scattering will also change the direction of light when it propagates in the material, reducing the projection rate of light and further achieving the matting effect.

[0033] Please refer to the table below, which is an experimental parameter of a specific embodiment.

[0034]

[0035]

[0036]

[0037] The preparation method of super-sensitive paper provided in the embodiment of the present application, the super-sensitive paper obtained by the method has the characteristics of high opacity, low glossiness, high printing color saturation, strong paper texture, good texture, etc. The super-sensitive paper has unique visual and tactile effects. In terms of touch, it has the characteristics of being rough, thick, and having obvious texture. In terms of vision, the product has low glossiness and can present unique color and texture effects after printing, which makes people feel the unique printing quality and quality value. It can be applied to high-end brands, art exhibitions, cover design, brochures, business cards and other fields. In addition, the preparation method is also characterized by simple process and low cost.

[0038] The above descriptions are only some embodiments of the present application, and do not limit the protection scope of the present application. Any equivalent device or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for preparing supersensitive paper, characterized in that: The preparation method comprises: Papermaking base paper; wherein the base paper comprises a surface layer, a surface lining layer, a core layer and a bottom layer which are stacked in sequence; the pulp of each layer comprises a whitening agent and a dye; A coating is performed on both the front and back sides of the base paper.

2. The preparation method according to claim 1, characterized in that: The pulp of the surface layer, the surface lining layer and the bottom layer all include: 15±5% coniferous pulp and 85±10% broadleaf pulp; the pulp of the core layer includes: 10±5% coniferous pulp, 50±10% broadleaf pulp, 35±10% chemical mechanical pulp and 5±5% damaged pulp.

3. The preparation method according to claim 2, characterized in that: The whitening agent in the pulp of the surface layer, the surface lining layer and the bottom layer is tetrasulfonic acid, and the added amount of the tetrasulfonic acid is 0.7%±0.1% of the absolute dry pulp of the pulp.

4. The preparation method according to claim 2, characterized in that: The whitening agent in the pulp of the core layer is disulfonic acid, and the addition amount of the disulfonic acid is 0.7%±0.2% of the absolute dry pulp of the pulp.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The pulp of the surface layer, the surface lining layer, the bottom layer and the core layer all contain a polyacrylamide-type retention aid, the molecular weight of the retention aid is above 8 million, and the addition amount is 250±50 ppm.

6. The preparation method according to claim 5, characterized in that: The pulp of the core layer also includes a polyacrylamide dry strength agent, the addition amount of which is 1.0±0.5%.

7. The preparation method according to claim 1, characterized in that: In the step of coating both the front and back sides of the base paper, the coating amount is 12.0±0.5 gsm.

8. The preparation method according to claim 1, characterized in that: In the step of coating both sides of the base paper, the coatings coated on both sides include: 20±10% GCC93, 60±10% GCC50, 20±10% PCC, 12±2% latex and 2±1% matting powder.

9. The preparation method according to claim 8, characterized in that: The latex is butadiene-styrene, and the glass transition temperature of the latex is -3 to -10°C; the particle size D50 of the matting powder is 4±2um.

10. A super sensitive paper, characterized in that: The super-sensitive paper is prepared by the preparation method described in any one of claims 1 to 9.

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