A fine dried noodle and a method for producing the same

Abstract

The present application relates to a kind of production method of fine paper kraft, including ready slurry, slurry, papermaking step.Different from prior art, the above technical solution uses regenerated pulp board and bamboo pulp board as raw material, and the regenerated pulp board is processed from waste paper, which realizes the recycling of fiber resources, greatly reduces the cost of raw materials and environmental load;The bamboo pulp board is taken from fast-growing bamboo, and the bamboo has short growth cycle and excellent fiber performance, which is an ideal green raw material to replace virgin wood pulp.The combination of regenerated pulp board and bamboo pulp board for fine paper kraft production can not only play the environmental protection and cost advantage of regenerated pulp, but also make up for the short board of insufficient strength of regenerated pulp by the fiber characteristics of bamboo pulp, to create a new type of fine paper kraft with performance up to standard and green environmental protection, which is of great significance to promote the transformation and upgrading of packaging paper industry.

Description

Technical Field

[0001] This invention relates to the field of papermaking technology, and in particular to a type of kraft paper with a facing surface and its preparation method. Background Technology

[0002] As a core paper material in the packaging industry, kraft paper combines high strength, high burst strength, and good printability, and is widely used in high-end packaging for food, home appliances, logistics, and other fields. Traditional high-performance kraft paper mainly uses virgin wood pulp as its raw material. While this ensures product quality, over-reliance on virgin wood resources exacerbates forest resource depletion and does not align with the paper industry's trend towards green, low-carbon, and sustainable development. Summary of the Invention

[0003] In view of the above problems, this application provides an economical and environmentally friendly kraft paperboard made from recycled pulp and bamboo pulp, and a method for preparing the same.

[0004] The first aspect of this application provides a method for preparing kraft paper for facial coating, comprising the following steps:

[0005] Preparation of slurry:

[0006] Recycled pulp preparation: The recycled pulp board is processed through low-consistency pulping, high-consistency slag removal, and coarse screening, and then sorted into short fiber, medium fiber, and long fiber by sieving.

[0007] The long fibers are subjected to low-concentration slag removal, first-stage fine screening, second-stage fine screening, multi-disc concentration, hot dispersion, long fiber pulping tower, and disc milling to obtain regenerated long fiber pulp; the medium fibers are subjected to low-concentration slag removal, light-weight slag removal, hot dispersion, medium fiber pulping tower, and disc milling to obtain regenerated medium fiber pulp; the short fibers are subjected to low-concentration slag removal and multi-disc concentration to obtain regenerated short fiber pulp.

[0008] Bamboo pulp preparation: After the bamboo pulp board is broken down by a hydraulic pulper, it passes through a high-consistency deslagging device and then enters a double-disc refiner for pulping to obtain bamboo pulp;

[0009] Pulp preparation:

[0010] Use 30%-40% bamboo pulp and 60%-70% recycled medium fiber pulp as the surface layer slurry;

[0011] 85%-95% recycled pulp and 5%-15% bamboo pulp are used as core and bottom layer pulps;

[0012] Copied:

[0013] The above pulp is dewatered and shaped in the wire section, laminated with the face and core, dewatered in the pressing section, dried in the pre-drying section, coated by the film transfer sizing machine, dried in the post-drying section, calendered, and then formed into paper.

[0014] Unlike existing technologies, the above technical solution provides a new type of kraft paperboard and its preparation process, using recycled pulp board and bamboo pulp board as raw materials, which saves costs and is energy-saving and environmentally friendly. The process is simple, easy to implement, and easy to promote.

[0015] Furthermore, the moisture content of the recycled pulp board is ≤13%, and the ash content is ≤6%.

[0016] Furthermore, the fiber parameters of the regenerated pulp board after dissociation are as follows: freeness ≥ 600ml, freeness ≥ 12°SR, wet weight ≥ 12g, fiber length 1.3-1.6mm, and fiber width ≥ 28um.

[0017] Furthermore, the degree of freeness of the regenerated fiber pulp is controlled at 25-30°SR, and the wet weight is 8-10g.

[0018] Furthermore, the degree of beating of the regenerated medium fiber pulp is controlled at 20-25°SR, and the wet weight is 5-7g.

[0019] Furthermore, the degree of beating of the recycled short fiber pulp is controlled at 25-30°SR, and the wet weight is 6.5-8.5g.

[0020] Furthermore, the degree of percussion of the bamboo pulp is controlled at 35-40°SR, and the wet weight is 9-11g.

[0021] The second aspect of this application provides a kraft paperboard for surface coating, which is prepared using the method described in the first aspect of this application.

[0022] Furthermore, the bursting strength index of the kraft paper reaches ≥3.5 kPa·m. 2 / g, tensile strength ≥7.5kN / m, flexural endurance (transverse) ≥100 cycles.

[0023] Furthermore, the hue values ​​of the kraft paper surface are: L value: 55±0.5, a value: 8.5±0.3, b value: 20.4±0.3.

[0024] Unlike existing technologies, the above-mentioned technical solution provides a new type of kraft paperboard. Its raw material, recycled pulp board, is processed from waste paper, achieving the recycling of fiber resources and significantly reducing raw material costs and environmental impact. The bamboo pulp board is made from fast-growing bamboo, which has a short growth cycle and excellent fiber properties, making it an ideal green raw material to replace virgin wood pulp. Combining recycled pulp board and bamboo pulp board in the production of kraft paperboard leverages the environmental and cost advantages of recycled pulp while utilizing the fiber characteristics of bamboo pulp to compensate for the insufficient strength of recycled pulp. This results in a new type of kraft paperboard that meets performance standards and is environmentally friendly, which is of great significance for promoting the transformation and upgrading of the packaging and papermaking industry.

[0025] The above description of the invention is merely an overview of the technical solution of this application. In order to enable those skilled in the art to better understand the technical solution of this application and to implement it based on the textual description, and to make the above-mentioned objectives and other objectives, features and advantages of this application easier to understand, the following description is based on the specific embodiments of this application. Detailed Implementation

[0026] To explain in detail the technical content, structural features, objectives, and effects of the technical solution, the following detailed description is provided in conjunction with specific embodiments.

[0027] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description is provided in conjunction with the specific embodiments listed. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended only as examples, not as limiting the scope of protection of this application.

[0028] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0029] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0030] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0031] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.

[0032] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0033] As understood in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0034] This application uses imported semi-finished recycled pulp board as raw material. This pulp board uses high-quality OCC recycled pulp board (waste kraft linerboard) as the core recycled raw material. The fiber source of this pulp board is stable, and even after multiple reuses, it retains a certain fiber length and toughness, with low impurity content and good uniformity. The advantages of recycled pulp board lie in realizing the resource utilization of waste paper, reducing the mining of virgin timber, lowering carbon emissions and water consumption during the production process, and significantly reducing raw material procurement costs, thus aligning with the requirements of circular economy development. However, recycled pulp fibers have certain issues with keratinization and reduced strength; using them alone is insufficient to meet the physical strength indicators of kraft linerboard, and performance optimization is necessary when combined with high-quality bamboo pulp.

[0035] This application uses high-quality bamboo pulp board as raw material. Bamboo is characterized by its rapid growth (it matures in 3-5 years) and strong renewability, making it a sustainable non-wood fiber raw material. Bamboo fibers are long, flexible, thin-walled, and highly porosity, possessing excellent tensile strength, bursting strength, and folding endurance. The fibers have strong interweaving ability, resulting in a smooth and delicate surface after papermaking, and excellent printability. Furthermore, bamboo pulp board does not contain resins or other impurities found in wood pulp, making the pulping process more environmentally friendly. It also exhibits good compatibility with recycled pulp, effectively improving the overall strength and surface quality of coated kraft paper and compensating for the performance deficiencies of recycled pulp.

[0036] The first aspect of this application provides a method for preparing kraft paper for facial coating, comprising the following steps:

[0037] Preparation of slurry:

[0038] Recycled pulp preparation: The recycled pulp board is processed through low-consistency pulping, high-consistency slag removal, and coarse screening, and then sorted into short fiber, medium fiber, and long fiber by sieving.

[0039] The long fibers are subjected to low-concentration slag removal, first-stage fine screening, second-stage fine screening, multi-disc concentration, hot dispersion, long fiber pulping tower, and disc milling to obtain regenerated long fiber pulp; the medium fibers are subjected to low-concentration slag removal, light-weight slag removal, hot dispersion, medium fiber pulping tower, and disc milling to obtain regenerated medium fiber pulp; the short fibers are subjected to low-concentration slag removal and multi-disc concentration to obtain regenerated short fiber pulp.

[0040] Bamboo pulp preparation: After the bamboo pulp board is broken down by a hydraulic pulper, it passes through a high-consistency deslagging device and then enters a double-disc refiner for pulping to obtain bamboo pulp. This step appropriately cuts the fibers, increases the degree of fiber fibrillation, enhances the fiber interlacing ability, and at the same time retains the strength advantage of bamboo fibers.

[0041] Pulp preparation:

[0042] Use 30%-40% bamboo pulp and 60%-70% recycled medium fiber pulp as the surface layer slurry;

[0043] 85%-95% recycled pulp and 5%-15% bamboo pulp are used as core and bottom layer pulps;

[0044] The surface layer uses a certain proportion of bamboo pulp and recycled medium fiber pulp to ensure the smoothness, strength and printing performance of the paper surface; the core layer and bottom layer are mainly made of recycled pulp, with a small amount of bamboo pulp to improve toughness, which reduces costs and maximizes the use of resources.

[0045] Through multiple trials and optimizations, the optimal ratio was determined to be 30%-40% bamboo pulp for the surface layer, 60%-70% recycled medium fiber pulp, 85%-95% recycled pulp for the core layer, and 5%-15% bamboo pulp, balancing product performance with environmental protection and cost advantages.

[0046] Copied:

[0047] The above pulp is dewatered and shaped in the wire section, laminated with the face and core, dewatered in the pressing section, dried in the pre-drying section, coated by the film transfer sizing machine, dried in the post-drying section, calendered, and then formed into paper.

[0048] This application is the first to efficiently combine recycled pulp board and bamboo pulp board, achieving complementary performance through layered pulp blending. This not only solves the problem of insufficient strength in recycled pulp but also overcomes the limitation of high cost when using bamboo pulp alone, creating a new product that combines "high performance, low cost, and environmental friendliness." Simultaneously, considering the fiber characteristics of recycled pulp and bamboo pulp, the disintegration, beating, and papermaking process parameters are optimized. Gentle purification and precise beating technologies are employed to maximize fiber strength retention, improve the three-layer paper web bonding strength, and avoid problems such as delamination and dusting.

[0049] Unlike existing technologies, the above-mentioned technical solution provides a new type of coated kraft paper and its preparation process, using recycled pulp board and bamboo pulp board as raw materials. Recycled pulp board is processed from waste paper, achieving the recycling of fiber resources and significantly reducing raw material costs and environmental impact. Bamboo pulp board is made from fast-growing bamboo, which has a short growth cycle and excellent fiber properties, making it an ideal green raw material to replace virgin wood pulp. Combining recycled pulp board and bamboo pulp board in the production of coated kraft paper leverages the environmental and cost advantages of recycled pulp while utilizing the fiber characteristics of bamboo pulp to compensate for the insufficient strength of recycled pulp, creating a new type of coated kraft paper that meets performance standards and is environmentally friendly. This is of great significance for promoting the transformation and upgrading of the packaging and papermaking industry.

[0050] Furthermore, in the recycled pulp preparation step: the recycled pulp board is put into a hydraulic pulper and broken down at a low concentration of 3%-5% to fully disperse the fibers; then, it is passed through a high-consistency desander and a coarse sieve (1.6mm aperture) to remove larger impurities, adhesives, metal particles, etc. from the pulp; then, the fibers are classified once (0.15mm sieve opening) to separate them into long fiber pulp, medium fiber pulp, and short fiber pulp into short fiber, medium fiber, and long fiber.

[0051] Furthermore, the moisture content of the recycled pulp board is ≤13%, and the ash content is ≤6%.

[0052] Furthermore, the fiber parameters of the regenerated pulp board after dissociation are as follows: freeness ≥ 600ml, freeness ≥ 12°SR, wet weight ≥ 12g, fiber length 1.3-1.6mm, and fiber width ≥ 28um.

[0053] Furthermore, the sieve opening of the long fiber pulp fine sieve is 0.17 mm.

[0054] Furthermore, the degree of freeness of the regenerated fiber pulp is controlled at 25-30°SR, and the wet weight is 8-10g.

[0055] Furthermore, the degree of beating of the regenerated medium fiber pulp is controlled at 20-25°SR, and the wet weight is 5-7g.

[0056] Furthermore, the degree of beating of the recycled short fiber pulp is controlled at 25-30°SR, and the wet weight is 6.5-8.5g.

[0057] Furthermore, the degree of percussion of the bamboo pulp is controlled at 35-40°SR, and the wet weight is 9-11g.

[0058] The second aspect of this application provides a kraft paperboard for surface coating, which is prepared using the method described in the first aspect of this application.

[0059] Furthermore, the bursting strength index of the kraft paper reaches ≥3.5 kPa·m. 2 / g, tensile strength ≥7.5kN / m, flexural endurance (transverse) ≥100 cycles.

[0060] Furthermore, the hue values ​​of the kraft paper surface are: L value: 55±0.5, a value: 8.5±0.3, b value: 20.4±0.3.

[0061] Unlike existing technologies, the above-mentioned technical solution provides a new type of kraft paper with a new facing. The kraft paper incorporates over 90% recycled pulp, reducing the use of virgin wood pulp and saving a significant amount of timber resources annually. Wastewater and exhaust emissions during production meet standards, with no toxic or harmful substances added, and the paper is fully recyclable, aligning with the industry's green packaging and low-carbon environmental protection principles. Kraft paper produced using this technology boasts high gloss and uniform ink absorption, suitable for various printing methods such as offset and flexographic printing, clearly displaying packaging designs and text, and enhancing the product's packaging quality. Furthermore, all strength indicators fully meet the industry standards for superior-grade products, satisfying the load-bearing and transportation requirements of high-end packaging.

[0062] Example 1: Preparation of regenerated pulp:

[0063] The recycled pulp board is fed into a hydraulic pulper and broken down at a low concentration (3%-5%) to fully disperse the fibers. Then, it is passed through a high-consistency desander and a coarse screen (1.6mm aperture) to remove larger impurities, adhesives, metal particles, etc. from the pulp. Finally, the fibers are classified once (0.15mm sieve opening) to separate them into short fibers, medium fibers, and long fibers.

[0064] Short fibers are processed through a low-concentration deslagging device and a multi-disc thickener to obtain recycled short fiber pulp. The freeness of the recycled short fiber pulp is controlled at 25-30°SR, and the wet weight is 6.5-8.5g.

[0065] The long fibers are subjected to low-concentration slag removal, first-stage fine screening (screen gap 0.17mm), second-stage fine screening (screen gap 0.17mm), multi-disc concentration, hot dispersion, long fiber pulping tower, and disc milling to obtain regenerated fiber pulp; the freeness of the regenerated fiber pulp is controlled at 25-30°SR, and the wet weight is 8-10g.

[0066] The medium fiber pulp is processed through low-concentration slag removal, light-weight slag removal, thermal dispersion, medium fiber pulping tower, and disc milling to obtain regenerated medium fiber pulp; the freeness of the regenerated medium fiber pulp is controlled at 20-25°SR, and the wet weight is 5-7g.

[0067] Example 2: Bamboo Pulp Preparation:

[0068] After being broken down by a hydraulic pulper, the bamboo pulp board passes through a high-consistency deslagging device and then enters a double-disc refiner for pulping. The beating degree of the bamboo pulp is controlled at 35-40°SR, and the wet weight is 9-11g. The fibers are appropriately cut to improve the degree of fiber fibrillation and enhance the fiber interlacing ability, while retaining the strength advantage of bamboo fibers.

[0069] Example 3: Preparation of kraft paper for face covering

[0070] Pulp preparation:

[0071] Use 30%-40% bamboo pulp and 60%-70% recycled medium fiber pulp as the surface layer slurry;

[0072] 85%-95% recycled pulp and 5%-15% bamboo pulp are used as core and bottom layer pulps;

[0073] According to the above layered pulping ratio, the recycled pulp and bamboo pulp are sent to the surface layer, core layer and bottom layer pulping tanks respectively. Add appropriate amounts of environmentally friendly retention and filtration aids and reinforcing agents, stir evenly, and control the pulp concentration of each layer to be stable to meet the requirements of the papermaking process.

[0074] The paper is made by using a long-wire multi-cylinder linerboard machine for layered papermaking. First, the surface layer, core layer and bottom layer of wet paper are formed separately. Then, the three layers of wet paper are tightly bonded together by composite pressing to form an integrated linerboard kraft paper wet sheet.

[0075] During the papermaking process, the wire speed, vacuum level, and press pressure are strictly controlled to ensure uniform dehydration of the wet paper and regular fiber distribution. Segmented drying in drying cylinders gradually increases the temperature, controlling the drying curve to prevent warping and cracking, and maintaining the paper moisture content at 7%-9%. After drying, the paper is calendered to improve surface smoothness and density, enhancing its printability; it is then wound and rewound.

[0076] The kraft paper prepared in Example 3 was subjected to quality testing. The kraft paper produced using this technology had a bursting strength index of ≥3.5 kPa·m. 2 / g, tensile strength ≥7.5kN / m, folding endurance (transverse) ≥100 times, all strength indicators fully meet the requirements of superior grade products in industry standards, and can meet the load-bearing and transportation needs of high-end packaging.

[0077] The surface layer uses a large amount of bamboo pulp fiber, giving the paper a smooth and delicate surface. It has high printing gloss and uniform ink absorption, making it suitable for various printing methods such as offset and flexographic printing. It can clearly present packaging patterns and text, enhancing the product packaging grade. The surface color hue values ​​are: L value: 55±0.5, a value: 8.5±0.3, b value: 20.4±0.3.

[0078] Meanwhile, the recycled pulp content of the kraft paperboard prepared in this embodiment reaches over 90%, reducing the use of virgin wood pulp and saving a significant amount of timber resources annually. Wastewater and exhaust emissions during the production process meet standards, with no toxic or harmful substances added, and the paperboard is fully recyclable, aligning with the industry's green packaging and low-carbon environmental protection development philosophy. Furthermore, the price of recycled pulp board is far lower than that of virgin wood pulp board. Bamboo pulp board is readily available and its cost is controllable. Compared to pure virgin wood pulp kraft paperboard, raw material costs are reduced by 15%-20%, while production energy consumption is lower, giving it stronger market competitiveness.

[0079] Finally, it should be noted that although the above embodiments have been described in the description of this application, this should not limit the scope of patent protection of this application. Any technical solutions that are based on the essential concept of this application, utilize the content described in this application's description to make equivalent structural or procedural substitutions or modifications, or directly or indirectly implement the technical solutions of the above embodiments in other related technical fields, are all included within the scope of patent protection of this application.

Claims

1. A method for preparing kraft paperboard, characterized in that, Includes the following steps: Preparation of slurry: Recycled pulp preparation: The recycled pulp board is processed through low-consistency pulping, high-consistency slag removal, and coarse screening, and then sorted into short fiber, medium fiber, and long fiber by sieving. The long fibers are subjected to low-concentration slag removal, first-stage fine screening, second-stage fine screening, multi-disc concentration, hot dispersion, long fiber pulping tower, and disc milling to obtain regenerated long fiber pulp; the medium fibers are subjected to low-concentration slag removal, light-weight slag removal, hot dispersion, medium fiber pulping tower, and disc milling to obtain regenerated medium fiber pulp; the short fibers are subjected to low-concentration slag removal and multi-disc concentration to obtain regenerated short fiber pulp. Bamboo pulp preparation: After the bamboo pulp board is broken down by a hydraulic pulper, it passes through a high-consistency deslagging device and then enters a double-disc refiner for pulping to obtain bamboo pulp; Pulp preparation: Use 30%-40% bamboo pulp and 60%-70% recycled medium fiber pulp as the surface layer slurry; 85%-95% recycled pulp and 5%-15% bamboo pulp are used as core and bottom layer pulps; Copied: The above pulp is dewatered and shaped in the wire section, laminated with the face and core, dewatered in the pressing section, dried in the pre-drying section, coated by the film transfer sizing machine, dried in the post-drying section, calendered, and then formed into paper.

2. The preparation method according to claim 1, characterized in that, The moisture content of the recycled pulp board is ≤13%, and the ash content is ≤6%.

3. The preparation method according to claim 1, characterized in that, The fiber properties of the recycled pulp board after dissociation are as follows: freeness ≥ 600ml, freeness ≥ 12°SR, wet weight ≥ 12g, fiber length 1.3-1.6mm, and fiber width ≥ 28um.

4. The preparation method according to claim 1, characterized in that, The degree of freeness of the regenerated fiber pulp is controlled at 25-30°SR, and the wet weight is 8-10g.

5. The preparation method according to claim 1, characterized in that, The degree of beating of the regenerated medium fiber pulp is controlled at 20-25°SR, and the wet weight is 5-7g.

6. The preparation method according to claim 1, characterized in that, The degree of freeness of the recycled short fiber pulp is controlled at 25-30°SR, and the wet weight is 6.5-8.5g.

7. The preparation method according to claim 1, characterized in that, The degree of percussion of the bamboo pulp is controlled at 35-40°SR, and the wet weight is 9-11g.

8. A type of kraft paper for noodles, characterized in that, The kraft paper used for the surface coating is prepared using the method described in any one of claims 1 to 7.

9. The kraft paperboard for noodles according to claim 8, characterized in that, The bursting strength index of the kraft paperboard reaches ≥3.5 kPa·m. 2 / g, tensile strength ≥7.5kN / m, flexural endurance (transverse) ≥100 cycles.

10. The kraft paperboard for face coverings according to claim 8, characterized in that, The hue values ​​of the kraft paper surface are: L value: 55±0.5, a value: 8.5±0.3, b value: 20.4±0.3.