Dyeing craft paper and preparation method thereof

Abstract

According to the dyed craft paper and the preparation method thereof, dyestuff is added into a surface layer, a lining layer, a core layer and a bottom layer for dyeing, so that the colors of four layers of sizing agents are close as much as possible, the hues of the front side and the back side are consistent, a coating step is not needed, and the cost is saved.

Description

Technical Field

[0001] The invention relates to the technical field of papermaking, and in particular to a dyed kraft paper and a preparation method thereof. Background Art

[0002] The front and back sides of dyed kraft paper have consistent colors, and the paper itself has good smoothness, stiffness and folding resistance, which can meet both simple printing requirements and packaging requirements. It is a high-quality material for making mid-to-high-end product packaging boxes and handbags.

[0003] The structure of double-sided red kraft paper is the surface layer, lining layer, core layer and bottom layer, and the color of the front and back paper is required to be consistent. At present, the purpose of dyeing is achieved by coating the surface layer and the bottom layer, but the cost of coating is high and the thickness of kraft paper is thick. Summary of the invention

[0004] In view of the above problems, the present application provides a low-cost dyed kraft paper. The above-mentioned dyed kraft paper needs to be dyed for the surface layer, lining layer, core layer and bottom layer, so that the colors of the four layers of pulp are as close as possible, and the colors of the front and back sides are consistent, avoiding affecting the appearance quality of the paper page and causing it to be unqualified.

[0005] The invention firstly discloses a dyed kraft paper, comprising a surface layer, a lining layer, a core layer and a bottom layer, and is characterized in that the surface layer pulp comprises BKP natural color wood pulp, DIP deinked pulp and ONP pulp; the lining layer pulp comprises OCC long fiber pulp; the core layer pulp comprises OCC long fiber pulp, OCC short fiber pulp, wood powder and damaged paper pulp; the bottom layer pulp comprises BKP natural color wood pulp, DIP deinked pulp and ONP pulp; and dyes are added to the surface layer, lining layer, core layer and bottom layer pulps.

[0006] Different from the prior art, the above technical solution provides a new dyed kraft paper. The above dyed kraft paper needs to be dyed for the facing layer, lining layer, core layer and bottom layer, so that the colors of the four layers of pulp are as close as possible, and the colors of the front and back sides are consistent. No coating step is required, which saves costs.

[0007] Furthermore, the surface layer pulp includes 8-10% BKP natural wood pulp, 45%-46% DIP deinked pulp and 45-46% ONP pulp; the lining layer pulp is OCC long fiber pulp; the core layer pulp includes 15-17% OCC long fiber pulp, 40-45% OCC short fiber pulp, 3-5% wood flour and 35-42% damaged paper pulp; the bottom layer pulp includes 8-10% BKP natural wood pulp, 45-46% DIP deinked pulp and 45-46% ONP pulp.

[0008] Furthermore, the freeness of the OCC long fiber pulp is 300-400, the freeness of the OCC short fiber pulp is 250-350, the freeness of the DIP deinked pulp is 280-350, the freeness of the BKP natural wood pulp is 140-180, and the freeness of the ONP pulp is 250-330.

[0009] Furthermore, 35-52 L / H yellow dye, 7-12 L / H red dye and 4-6 L / H black dye are added to the surface layer slurry, 25-26 L / H yellow dye and 4-5 L / H red dye are added to the lining layer slurry, 200-240 L / H yellow dye and 14-25 L / H red dye are added to the core layer slurry, and 42-62 L / H yellow dye, 8-13 L / H red dye and 6-7.5 L / H black dye are added to the bottom layer slurry.

[0010] Furthermore, the L value of the dyed kraft paper is 68.5-70.5; the a value is 9.9-10.5; the b value is

[0011] =23.2-23.8.

[0012] Furthermore, the surface layer pulp includes 20-40% BKP bleached wood pulp, 10%-30% DIP deinked pulp and 30-60% ONP pulp; the lining layer pulp is OCC long fiber pulp; the core layer pulp includes 15-20% OCC long fiber pulp, 50-60% OCC short fiber pulp, 3-5% wood powder and 20-35% damaged paper pulp; the bottom layer pulp includes 23-30% BKP bleached wood pulp, 10-20% DIP deinked pulp and 57-60% ONP pulp. Furthermore, 40-58 L / H yellow dye, 11-15 L / H red dye, and 0.5-4.5 L / H black dye are added to the surface layer slurry, 26 L / H yellow dye and 6 L / H red dye are added to the lining layer slurry, 240-260 L / H yellow dye and 45-50 L / H red dye are added to the core layer slurry, and 45-55 L / H yellow dye, 10-15 L / H red dye, and 1-2.5 L / H black dye are added to the bottom layer slurry.

[0013] Furthermore, the L value of the dyed kraft paper is 60-62; the a value is 12.2-12.8; the b value is

[0014] =21.7-22.3.

[0015] Furthermore, the freeness of the OCC long fiber pulp is 300-400, the freeness of the OCC short fiber pulp is 250-350, the freeness of the DIP deinked pulp is 250-350, the freeness of the BKP natural wood pulp is 150-200, and the freeness of the ONP pulp is 250-330.

[0016] The present invention also provides a method for preparing a dyed kraft paper, wherein the dyed kraft paper is any one of the dyed kraft paper described above, and the preparation method comprises the following steps:

[0017] S10, Preparation of domestic waste OCC pulp:

[0018] S101: After feeding, crushing, high-concentration slag removal and coarse screening, the formulated domestic waste OCC raw materials are graded and sorted into domestic waste OCC long fibers and domestic waste OCC short fibers;

[0019] S102: After low-concentration slag removal, fine screening, multi-disc concentration, and thermal dispersion, the long fibers are subjected to disk grinding to obtain OCC long fiber pulp, which is then sent to a mixed pulp tank for pulping;

[0020] S103: After the domestic waste OCC short fibers are concentrated by multiple discs, domestic waste OCC short fiber pulp is obtained, and the pulp is sent to a mixed pulp tank for pulping;

[0021] S20, preparation of BKP natural wood pulp: 100% commercial natural wood pulp is subjected to pulping, high-consistency deslagging, and disc grinding to obtain BKP natural wood pulp, which is then sent to a mixing pulp tank for pulping;

[0022] S30, preparation of DIP deinked pulp: using domestic waste second white as raw material, after being processed by DIP deinking pulp line, DIP deinked pulp is obtained and sent to the mixing pulp tank for pulping;

[0023] S40, preparation of ONP pulp: using domestic waste second white and domestic waste grade A as raw materials, after pulping, high-concentration deslagging, coarse screening, low-concentration deslagging, fine screening, flotation, multi-disc concentration, thermal dispersion, and disc grinding, ONP pulp is obtained and sent to the mixing pulp tank for pulping;

[0024] S50, preparation of broken paper pulp: using production broken paper as raw material, the broken paper pulp is obtained after being processed by the AOCC broken paper pulp production line, and sent to the mixing pulp tank for pulping;

[0025] S60, preparation of wood powder slurry: using wood powder as raw material, after being processed by a wood pulp production line, obtaining wood powder slurry, and sending it to a mixing slurry tank for slurry preparation;

[0026] S70, slurry preparation: slurry preparation is performed according to a formula, dye is added into the slurry, and a surface layer slurry, a core layer slurry, a lining layer slurry and a bottom layer slurry are obtained;

[0027] S80, adding dye: adding dye to the surface layer slurry, the core layer slurry, the lining layer slurry and the bottom layer slurry respectively;

[0028] S90, papermaking: the surface layer pulp, core layer pulp, lining layer pulp and bottom layer pulp added with dye are respectively flowed into the headbox through the pulp filling pump and the pressure screen, and then sent to the wire part for wire dehydration and forming, and then subjected to the pressing and dehydration in the pressing part, drying in the front drying part, surface sizing, drying in the back drying part, calendering, winding and rewinding to make the dyed kraft paper.

[0029] The above-mentioned records related to the invention content are only an overview of the technical solution of the present application. In order to enable ordinary technicians in the field to more clearly understand the technical solution of the present application, and then implement it according to the written contents of the specification, and to make the above-mentioned purpose and other purposes, features and advantages of the present application easier to understand, the specific implementation methods of the present application are explained below. DETAILED DESCRIPTION

[0030] In order to explain the technical content, structural features, achieved objectives and effects of the technical solution in detail, the following is a detailed description in conjunction with specific embodiments.

[0031] In order to explain in detail the possible application scenarios, technical principles, specific schemes that can be implemented, and the purposes and effects that can be achieved, the following is a detailed description in conjunction with the specific embodiments listed. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0032] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0033] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0034] In the description of this application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that three relationships may exist, for example, A and / or B, which means: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this article generally indicates that the objects before and after are in an "or" logical relationship.

[0035] In the present application, terms such as “first” and “second” are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship of quantity, priority or sequence between these entities or operations.

[0036] Without further limitations, in this application, the words "include", "comprises", "has" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those limited elements, but also other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0037] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than", "less than", "exceed" and the like are understood to exclude the number itself; expressions such as "above", "below", "within" and the like are understood to include the number itself. In addition, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups", "multiple times", etc., unless otherwise clearly and specifically limited.

[0038] The freeness described in this embodiment is a characterization of the water-draining performance of the pulp. Generally speaking, the larger the freeness of the pulp, the faster the water-draining speed. The paper stock forms a sheet during the dehydration process, and the paper sheet is continuously dehydrated during the forming process. On the one hand, the paper sheet formation requires the removal of a large amount of water, but the dehydration cannot be too fast. If the dehydration is too fast or too urgent, the paper stock fibers will be formed before they can be evenly distributed on the net, and it is difficult to form a good quality paper sheet. On the other hand, if the dehydration is too slow, it will cause the dispersed fibers to re-flocculate.

[0039] In this embodiment, OCC is the abbreviation of Old Corrugated Container, which is translated as cardboard waste paper.

[0040] Types, definitions and quality judgment standards of domestic waste OCC slurry raw materials.

[0041] The inventor divides domestic waste raw materials into 5 levels according to different standards. In specific production, different raw materials can be selected according to customer needs. The classification, definition, and quality judgment standard table of specific domestic waste raw materials are as follows:

[0042]

[0043] In this embodiment, the broken paper is paper that is abnormally broken during the papermaking process of the paper machine, and the scrap paper that is trimmed and trimmed during the rewinding of the finishing part.

[0044] In this embodiment, domestic waste paper is a general term for waste paper, including undyed book pages, office waste paper, less than 20% coated paper and other types of waste paper.

[0045] Example 1 Red kraft paper and preparation method thereof

[0046] S10, Preparation of domestic waste OCC pulp:

[0047] S101: After feeding, crushing, high-concentration slag removal and coarse screening, domestic waste OCC raw materials (domestic waste A grade 75wt%, paper substitute pulp 25%) are graded and sorted into domestic waste OCC long fibers and domestic waste OCC short fibers;

[0048] S102: After low-concentration slag removal, fine screening, multi-disc concentration, and thermal dispersion, the long fiber is subjected to disk grinding to obtain OCC long fiber pulp, which is sent to a mixed pulp tank for pulping; the freeness of the OCC long fiber pulp is 300-400 ml, and the pH value is 6.5-7.5;

[0049] S103: The domestic waste OCC short fibers are concentrated through multiple discs to obtain domestic waste OCC short fiber pulp, which is sent to a mixed pulp tank for pulping; the freeness of the OCC short fiber pulp is 250-350 ml, and the pH value is 6.5-7.5.

[0050] S20, preparation of BKP natural wood pulp: the commercial natural wood pulp is subjected to pulping, high-concentration deslagging, and disc grinding to obtain BKP natural wood pulp, which is sent to a mixed pulp tank for pulping; the freeness of the BKP natural wood pulp is 150-200ml, the pulp whiteness is 20±3, and the pH value is 7-8;

[0051] S30, preparation of DIP deinked pulp: using domestic waste second white as raw material, after DIP deinked pulp line treatment to obtain DIP deinked pulp, sent to the mixing pulp pool for pulping; the freeness of the DIP deinked pulp is 250-350ml, the pulp whiteness is 65±3, and the pH value is 6.5-7.5.

[0052] S40, preparation of broken paper pulp: using production broken paper as raw material, the broken paper pulp is obtained after being processed by the AOCC broken paper pulp production line, and sent to the mixing pulp tank for pulping;

[0053] S50, preparation of wood powder slurry: using wood powder as raw material, processing it through a wood pulp production line to obtain wood powder slurry, and sending it to a mixing slurry tank for slurry preparation;

[0054] S60, preparation of ONP pulp: using 50wt% domestic waste second white and 50wt% domestic waste A grade as raw materials, after pulping, high-concentration deslagging, coarse screening, low-concentration deslagging, fine screening, flotation, multi-disc concentration, thermal dispersion, disc grinding, ONP pulp is obtained and sent to a mixing pulp pool for pulping; the freeness of the ONP pulp is 250-350ml, and the pH value is 6-7.

[0055] S70, slurry preparation: slurry preparation is performed according to the formula to obtain surface layer slurry, core layer slurry, lining layer slurry and bottom layer slurry;

[0056] The surface layer pulp comprises 20-40% BKP bleached wood pulp, 10%-30% DIP deinked pulp and 30-60% ONP pulp;

[0057] The lining slurry is OCC long fiber pulp;

[0058] The core layer pulp comprises 15-20% OCC long fiber pulp, 50-60% OCC short fiber pulp, 3-5% wood flour and 20-35% broken paper pulp;

[0059] The bottom pulp includes 23-30% BKP bleached wood pulp, 10-20% DIP deinked pulp and 57-60% ONP pulp.

[0060] S80. Add dyes: add dyes to the surface layer slurry, core layer slurry, lining layer slurry and bottom layer slurry respectively; add 40-58 L / H yellow dye, 11-15 L / H red dye and 0.5-4.5 L / H black dye to the surface layer slurry, add 26 L / H yellow dye and 6 L / H red dye to the lining layer slurry, add 240-260 L / H yellow dye and 45-50 L / H red dye to the core layer slurry, and add 45-55 L / H yellow dye, 10-15 L / H red dye and 1-2.5 L / H black dye to the bottom layer slurry.

[0061] S90, papermaking: the surface layer pulp, core layer pulp, lining layer pulp and bottom layer pulp with dye added are respectively fed into the headbox through a pulp filling pump and a pressure screen, and then sent to the wire section for dehydration and forming, and then subjected to dehydration in the pressing section, drying in the front drying section, surface sizing, drying in the back drying section, calendering, winding and rewinding to produce the red kraft paper.

[0062] The L value of the front and back sides of the red kraft paper is 60-62; the a value is 12.2-12.8; and the b value is 21.7-22.3.

[0063] Example 2 Light red kraft paper and preparation method thereof

[0064] S10, Preparation of domestic waste OCC pulp:

[0065] S101: After feeding, crushing, high-concentration slag removal and coarse screening, domestic waste OCC raw materials (domestic waste grade A 40wt%, domestic waste second white 60%) are graded and sorted into domestic waste OCC long fibers and domestic waste OCC short fibers;

[0066] S102: After low-concentration slag removal, fine screening, multi-disc concentration, and thermal dispersion, the long fiber is subjected to disk grinding to obtain OCC long fiber pulp, which is sent to a mixed pulp tank for pulping; the freeness of the OCC long fiber pulp is 300-400 ml, and the pH value is 6.5-7.5;

[0067] S103: The domestic waste OCC short fibers are concentrated through multiple discs to obtain domestic waste OCC short fiber pulp, which is sent to a mixed pulp tank for pulping; the freeness of the OCC short fiber pulp is 250-350 ml, and the pH value is 6.5-7.5.

[0068] S20, preparation of BKP natural wood pulp: the commercial natural wood pulp is subjected to pulping, high-concentration deslagging, and disc grinding to obtain BKP natural wood pulp, which is sent to a mixed pulp tank for pulping; the freeness of the BKP natural wood pulp is 140-180ml, the pulp whiteness is 20±3%, and the pH value is 7-8;

[0069] S30, preparation of DIP deinked pulp: using domestic waste second white as raw material, after DIP deinked pulp line treatment to obtain DIP deinked pulp, sent to the mixing pulp pool for pulping; the freeness of the DIP deinked pulp is 280-350ml, the pulp whiteness is 65±3%, and the pH value is 6.5-7.5.

[0070] S40, preparation of broken paper pulp: using production broken paper as raw material, the broken paper pulp is obtained after being processed by the AOCC broken paper pulp production line, and sent to the mixing pulp tank for pulping;

[0071] S50, preparation of wood powder slurry: using wood powder as raw material, processing it through a wood pulp production line to obtain wood powder slurry, and sending it to a mixing slurry tank for slurry preparation;

[0072] S60, preparation of ONP pulp: using domestic waste second white as raw material, after pulping, high-concentration deslagging, coarse screening, low-concentration deslagging, fine screening, flotation, multi-disc concentration, thermal dispersion, disc grinding, ONP pulp is obtained and sent to a mixing pulp pool for pulping; the freeness of the ONP pulp is 250-330ml, the pulp whiteness is 65±3%, and the pH value is 6.5-7.5.

[0073] S70, slurry preparation: slurry preparation is performed according to the formula to obtain surface layer slurry, core layer slurry, lining layer slurry and bottom layer slurry;

[0074] The surface layer pulp comprises 8-10% BKP natural wood pulp, 45%-46% DIP deinked pulp and 45-46% ONP pulp;

[0075] The lining layer pulp is OCC long fiber pulp; the core layer pulp includes 15-17% OCC long fiber pulp, 40-45% OCC short fiber pulp, 3-5% wood powder and 35-42% damaged paper pulp; the bottom layer pulp includes 8-10% BKP natural wood pulp, 45-46% DIP deinked pulp and 45-46% ONP pulp.

[0076] S80, adding dyes: adding dyes to the surface layer slurry, core layer slurry, lining layer slurry and bottom layer slurry respectively; adding 35-52 L / H yellow dye, 7-12 L / H red dye and 4-6 L / H black dye to the surface layer slurry, adding 25-26 L / H yellow dye and 4-5 L / H red dye to the lining layer slurry, adding 200-240 L / H yellow dye and 14-25 L / H red dye to the core layer slurry, adding 42-62 L / H yellow dye, 8-13 L / H red dye and 6-7.5 L / H black dye to the bottom layer slurry.

[0077] S90, papermaking: the surface layer slurry, core layer slurry, lining layer slurry and bottom layer slurry with dye added are respectively fed into the headbox through the slurry filling pump and the pressure screen, and then sent to the wire part for dehydration and forming, and then subjected to dehydration in the pressing part, drying in the front drying part, surface sizing, drying in the back drying part, calendering, winding and rewinding to produce the light red kraft paper. The front and back sides of the light red kraft paper have L values ​​of 68.5-70.5, a value of 9.9-10.5 and b value of 23.2-23.8.

[0078] Finally, it should be noted that although the above embodiments have been described in the text of the specification of this application, this does not limit the scope of patent protection of this application. All technical solutions generated by replacing or modifying equivalent structures or equivalent processes based on the essential concept of this application using the contents recorded in the text of the specification of this application, as well as directly or indirectly implementing the technical solutions of the above embodiments in other related technical fields, are included in the scope of patent protection of this application.

Claims

1. A dyed kraft paper, comprising a surface layer, a lining layer, a core layer and a bottom layer, characterized in that: The surface layer pulp includes BKP natural color wood pulp, DIP deinked pulp and ONP pulp; the lining layer pulp includes OCC long fiber pulp; the core layer pulp includes OCC long fiber pulp, OCC short fiber pulp, wood powder and broken paper pulp; the bottom layer pulp includes BKP natural color wood pulp, DIP deinked pulp and ONP pulp; dyes are added to the surface layer, lining layer, core layer and bottom layer pulps.

2. The dyed kraft paper according to claim 1, characterized in that: The surface layer pulp includes 8-10% BKP natural wood pulp, 45%-46% DIP deinked pulp and 45-46% ONP pulp; the lining layer pulp is OCC long fiber pulp; the core layer pulp includes 15-17% OCC long fiber pulp, 40-45% OCC short fiber pulp, 3-5% wood powder and 35-42% damaged paper pulp; the bottom layer pulp includes 8-10% BKP natural wood pulp, 45-46% DIP deinked pulp and 45-46% ONP pulp.

3. The dyed kraft paper according to claim 2, characterized in that: The freeness of the OCC long fiber pulp is 300-400 ml, the freeness of the OCC short fiber pulp is 250-350 ml, the freeness of the DIP deinked pulp is 280-350 ml, the freeness of the BKP natural wood pulp is 140-180 ml, and the freeness of the ONP pulp is 250-330 ml.

4. The dyed kraft paper according to claim 2, characterized in that: 35-52 L / H yellow dye, 7-12 L / H red dye and 4-6 L / H black dye are added to the surface layer slurry, 25-26 L / H yellow dye and 4-5 L / H red dye are added to the lining layer slurry, 200-240 L / H yellow dye and 14-25 L / H red dye are added to the core layer slurry, and 42-62 L / H yellow dye, 8-13 L / H red dye and 6-7.5 L / H black dye are added to the bottom layer slurry.

5. The dyed kraft paper according to claim 2, characterized in that: The dyed kraft paper has an L value of 68.5-70.5, a value of 9.9-10.5, and b value of 23.2-23.

8.

6. The dyed kraft paper according to claim 1, characterized in that: The surface layer pulp includes 20-40% BKP bleached wood pulp, 10%-30% DIP deinked pulp and 30-60% ONP pulp; the lining layer pulp is OCC long fiber pulp; the core layer pulp includes 15-20% OCC long fiber pulp, 50-60% OCC short fiber pulp, 3-5% wood powder and 20-35% damaged paper pulp; the bottom layer pulp includes 23-30% BKP bleached wood pulp, 10-20% DIP deinked pulp and 57-60% ONP pulp.

7. The dyed kraft paper according to claim 6, characterized in that: 40-58 L / H yellow dye, 11-15 L / H red dye, and 0.5-4.5 L / H black dye are added to the surface layer slurry, 26 L / H yellow dye and 6 L / H red dye are added to the lining layer slurry, 240-260 L / H yellow dye and 45-50 L / H red dye are added to the core layer slurry, and 45-55 L / H yellow dye, 10-15 L / H red dye, and 1-2.5 L / H black dye are added to the bottom layer slurry.

8. The dyed kraft paper according to claim 6, characterized in that: The dyed kraft paper has an L value of 60-62, an a value of 12.2-12.8, and a value of 21.7-22.

3.

9. The dyed kraft paper according to claim 6, characterized in that: The freeness of the OCC long fiber pulp is 300-400, the freeness of the OCC short fiber pulp is 250-350, the freeness of the DIP deinked pulp is 250-350, the freeness of the BKP natural wood pulp is 150-200, and the freeness of the ONP pulp is 250-330.

10. A method for preparing dyed kraft paper, characterized in that: The dyed kraft paper is the dyed kraft paper according to any one of claims 1 to 9, and the preparation method comprises the following steps: S10, Preparation of domestic waste OCC pulp: S101: After feeding, crushing, high-concentration slag removal and coarse screening, the formulated domestic waste OCC raw materials are graded and sorted into domestic waste OCC long fibers and domestic waste OCC short fibers; S102: After low-concentration slag removal, fine screening, multi-disc concentration, and thermal dispersion, the long fibers are subjected to disk grinding to obtain OCC long fiber pulp, which is then sent to a mixed pulp tank for pulping; S103: After the domestic waste OCC short fibers are concentrated by multiple discs, domestic waste OCC short fiber pulp is obtained, and the pulp is sent to a mixed pulp tank for pulping; S20, preparation of BKP natural wood pulp: 100% commercial natural wood pulp is subjected to pulping, high-concentration deslagging, and disc grinding to obtain BKP natural wood pulp, which is then sent to a mixed pulp tank for pulping; S30, preparation of DIP deinked pulp: using domestic waste second white as raw material, after being processed by DIP deinking pulp line, DIP deinked pulp is obtained and sent to the mixing pulp tank for pulping; S40, preparation of ONP pulp: using domestic waste second white and domestic waste grade A as raw materials, after pulping, high-concentration deslagging, coarse screening, low-concentration deslagging, fine screening, flotation, multi-disc concentration, thermal dispersion, and disc grinding, ONP pulp is obtained and sent to the mixing pulp tank for pulping; S50, preparation of broken paper pulp: using production broken paper as raw material, the broken paper pulp is obtained after being processed by the AOCC broken paper pulp production line, and sent to the mixing pulp tank for pulping; S60, preparation of wood powder slurry: using wood powder as raw material, after being processed by a wood pulp production line, obtaining wood powder slurry, and sending it to a mixing slurry tank for slurry preparation; S70, slurry preparation: slurry preparation is performed according to a formula, dye is added into the slurry, and a surface layer slurry, a core layer slurry, a lining layer slurry and a bottom layer slurry are obtained; S80, adding dye: adding dye to the surface layer slurry, the core layer slurry, the lining layer slurry and the bottom layer slurry respectively; S90, papermaking: the surface layer pulp, core layer pulp, lining layer pulp and bottom layer pulp added with dye are respectively flowed into the headbox through the pulp filling pump and the pressure screen, and then sent to the wire part for wire dehydration and forming, and then subjected to the pressing and dehydration in the pressing part, drying in the front drying part, surface sizing, drying in the back drying part, calendering, winding and rewinding to make the dyed kraft paper.

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