A method for preparing a cotton fiber-containing cream paper base paper

Abstract

The application discloses a preparation method of cotton-containing lotion paper base paper, which comprises the following steps: selecting cotton fibers with specific length, Mack value and adding amount, then selecting wood pulp components including coniferous wood pulp and broadleaf wood pulp, sequentially performing warm water permeation treatment, composite cellulase treatment and inactivation treatment on the cotton fibers to obtain pretreated cotton fibers, separately performing hydraulic defibration on the pretreated cotton fibers to form cotton fiber dispersed slurry, adding the coniferous wood pulp into the cotton fiber dispersed slurry, performing disintegration and beating to form long fiber interlocking slurry, performing disintegration and defibration on the broadleaf wood pulp to form short fiber slurry, adding the short fiber slurry into the long fiber interlocking slurry after the long fiber interlocking slurry is formed to perform slurry mixing, obtaining pulp pool slurry, and performing forming, pressing, drying, creping, winding and slitting to obtain the cotton-containing lotion paper base paper, which has the advantages of sufficient pretreatment, stable beating process, reasonable long and short fiber cooperation, low risk of falling off and convenience of subsequent lotion coating processing.

Description

Technical Field

[0001] This invention belongs to the field of cream paper preparation technology, specifically relating to a method for preparing cotton fiber cream paper base paper. Background Technology

[0002] Cream-coated paper is a special type of household paper made from regular tissue paper as the base material, with a cream component introduced onto the paper surface through post-processing methods such as coating, roller coating, or spray coating. Compared with ordinary facial tissues, cream-coated paper not only requires better softness and skin-friendliness, but also needs to have a certain degree of moisture retention, low irritation, and integrity during use. Therefore, it is widely used in scenarios such as maternal and infant care, wiping for rhinitis and colds, facial cleansing, and daily care for people with sensitive skin. Moreover, because the cream component needs to adhere to and penetrate into the fiber network of the base paper, and the base paper of cream-coated paper needs to meet the basis weight, softness, and strength requirements of regular tissue paper, it also needs to take into account bulk, liquid absorption, wet strength, and lint control. If the base paper is too... If the paper is too dense, the cream components will not be easily absorbed evenly. If the strength of the base paper is insufficient, it will be prone to damage, shedding, or surface fuzzing during coating, winding, slitting, and use. At the same time, most existing base papers for cream paper use wood pulp fibers as the core raw material. Softwood pulp, as a long fiber raw material, mainly provides the strength support of the paper, while hardwood pulp, as a short fiber raw material, mainly improves the fineness of the paper. The typical ratio of softwood pulp to hardwood pulp is 2:8 to 4:6. These wood pulp fiber blending methods can meet the basic papermaking requirements of ordinary cream paper base paper, but its performance adjustment mainly depends on the change of the ratio of long and short fibers. It is difficult to further improve the velvety feel, bulk, and cream absorption adaptability of the base paper without significantly sacrificing strength or softness.

[0003] To meet market demand for softness in creamed paper, existing processes typically employ two methods for adjustment. First, the ratio of softwood pulp to hardwood pulp is reduced to 1:9 to 2:8 to improve paper softness. However, this method can easily lead to a decrease in the tensile strength of the base paper, resulting in problems such as tearing, shedding, and insufficient wet strength during use. Second, more chemical softeners, such as cationic surfactants, are added. While this can improve the paper's feel, it can reduce the bonding strength between fibers and may increase the risk of skin irritation. Finally, relying solely on wood pulp fibers for long and short fiber blending makes it difficult to balance high toughness and a velvety feel. The base paper tends to be either too hard or too slippery, lacking the soft texture of natural fibers and affecting the uniform adsorption and adhesion of the cream to the base paper surface.

[0004] Currently, a few solutions attempt to add natural fibers such as cotton pulp, bamboo fiber, and hemp fiber to improve paper performance. However, most of these solutions only use natural fibers as ordinary fiber raw materials in pulping or beating processes. They do not design corresponding pretreatment and beating sequences to balance the softness, toughness, bulk, and lint-shedding properties of the base paper. The use of these methods still has many problems. When the natural fiber length is too long, it is easy to cause pulp flocculation and poor paper uniformity. When the proportion of natural fiber added is too high, it is easy to cause a decrease in softness and an increase in production costs. When the natural fiber is not fully swollen, loosened, and orderly beated, it is easy to cause problems such as insufficient dispersion, local agglomeration, or excessive cutting during the pulping process. As a result, it is difficult for natural fibers to form a stable and uniform fiber network structure with wood pulp fibers. All of these affect the quality of the coated paper.

[0005] Therefore, there is an urgent need for a method to prepare cotton fiber cream paper base paper to solve the problems of existing cream paper base paper, such as difficulty in achieving both softness and toughness, easy breakage, easy shedding, insufficient velvet feel, and poor uniformity of cream adsorption. Summary of the Invention

[0006] In view of this, the present invention proposes a method for preparing cotton fiber cream paper base paper, which is applied to the field of cream paper preparation technology, and solves the existing technical problems of cream paper base paper being difficult to balance in terms of softness and toughness, easy to break, easy to shed lint, insufficient velvet feel, and poor uniformity of cream adsorption.

[0007] To achieve the above-mentioned technical objectives, the specific technical solution adopted by the present invention is as follows: A method for preparing cotton fiber latex paper base paper includes the following steps: S1. Select raw materials. Based on the total mass of fiber raw materials, select cotton fiber and wood pulp components. The cotton fiber is selected from Xinjiang long-staple cotton pulp board. The length of the cotton fiber is 1.0mm-1.5mm and the micronaire value is 3.7-4.2. The amount of cotton fiber added is 1%-3%. The wood pulp components include softwood pulp and hardwood pulp. Softwood pulp accounts for 25%-40% of the mass of the wood pulp components, and hardwood pulp accounts for 60%-75% of the mass of the wood pulp components. Based on the total mass of oven-dry pulp, the amount of production aids added is 0.1%-1%. The production aids include one or more of wet strength agents, dispersants, and defoamers. S2. Pre-treatment of cotton fibers: The cotton fibers are placed in warm water at 45℃-55℃, and a penetrant of 0.2%-0.4% by weight of the cotton fibers is added for 1-1.5 hours. Then, a compound cellulase of 0.05%-0.15% by weight of the cotton fibers is added, and the mixture is kept at 48℃-52℃ for 1-2 hours. Subsequently, the temperature is raised to 70℃-80℃ and kept at 70℃-80℃ for 10-15 minutes for inactivation treatment to obtain pre-treated cotton fibers. This process allows the cotton fibers to swell and reduce rigidity before entering the subsequent desizing and pulping processes. S3. Separately disperse cotton fibers. The pretreated cotton fibers are separately hydraulically dispersed at a concentration of 3%-4% for 5-10 minutes. This allows the pretreated cotton fibers, which have been swollen and have reduced rigidity, to disperse into a cotton fiber dispersion slurry before the softwood pulp is added. This reduces the local agglomeration of the pretreated cotton fibers during the subsequent mixing, disintegration, and pulping process with the softwood pulp. S4. Co-processing cotton fibers and softwood pulp: Under the condition that the cotton fiber dispersion pulp is kept in a hydraulically disintegrated state, softwood pulp is added to the cotton fiber dispersion pulp, so that the pre-treated cotton fibers and softwood pulp are mixed in a continuously dispersed state, and then broken down and pulped to form a long fiber interlocking pulp. The freeness of the long fiber interlocking pulp is 24°SR-30°SR. In the long fiber interlocking pulp, the pre-treated cotton fibers and softwood pulp long fibers interlock to form an interlocking skeleton. S5. Processing hardwood pulp: Hardwood pulp is fed into a short fiber hydraulcer for disintegration, then pumped into a pre-disintegration short fiber pulp tank. After being processed by a disintegrator, it is pumped into a post-disintegration short fiber pulp tank to obtain short fiber pulp. The disintegration degree of the short fiber pulp is 22°SR-26°SR to ensure that the short fiber pulp maintains its dispersion and filling capacity. S6. Slurry preparation: After the short fiber slurry is formed, it is added to the long fiber interlocking slurry for slurry preparation, so that the short fiber slurry fills the interlocking skeleton formed by the long fiber interlocking slurry. During the slurry preparation or slurry formation process, production aids are added to obtain the slurry in the slurry tank. S7. Forming and creping: The pulp from the pulping tank is pumped into the headbox and then into the tissue paper machine for forming, pressing and drying. The paper sheet dried to a dryness of 55%-85% is creped by a doctor blade, then wound and slit to obtain cotton fiber cream paper base paper.

[0008] Furthermore, in step S3, the pretreated cotton fibers are individually hydraulically dispersed to form uniformly dispersed single fibers, so as to avoid the cotton fibers not being completely dispersed and thus forming agglomerates during the subsequent pulping process.

[0009] Furthermore, in step S4, softwood pulp is slowly added to the cotton fiber dispersion pulp to make the pretreated cotton fiber and softwood pulp evenly mixed and then broken down. Then it is sent to the long fiber pre-pulping tank, pulped by a refiner, and then sent to the long fiber post-pulping tank.

[0010] Furthermore, in step S4, the degree of dissociation of the long-fiber interlocking pulp is 26°SR-28°SR, so that the pretreated cotton fibers and the long fibers of softwood pulp form a fiber bond structure and reduce excessive cutting of the long fibers.

[0011] Furthermore, in step S1, the cotton fiber uses Yinshan brand cotton pulp board, which is made from Xinjiang long-staple cotton. In step S2, the penetrant is fatty alcohol polyoxyethylene ether, and the composite cellulase is added after the penetrant soaking treatment.

[0012] Furthermore, in step S6, the flow rates of the long-fiber interlocking pulp and the short-fiber pulp are adjusted so that the long-fiber interlocking pulp and the short-fiber pulp are mixed in the mixing tank at a mass ratio of 22-28:78-72, so that while the long-fiber interlocking pulp provides strength support, the short-fiber pulp supplements the paper's fineness and paper uniformity.

[0013] Furthermore, in step S6, during the mixing process of long fiber interlocked slurry and short fiber slurry in the mixing tank, the white water return flow rate is adjusted to regulate the fine fiber content in the slurry entering the pulping tank. After the short fiber slurry and long fiber interlocked slurry enter the mixing tank, they are treated by a leveling mill and then pumped into the pulping tank. The freeness of the slurry in the pulping tank is 25°SR-30°SR.

[0014] Furthermore, in step S6, the production aids include a wet strength agent, which is a polyamide epichlorohydrin resin with a solid content of 12.5% ​​and an addition amount of 20 kg / t, to enhance the bonding strength between the short fiber pulp and the long fiber interlocking pulp. In step S7, the doctor blade is a titanium alloy doctor blade or a carbon steel doctor blade, and the paper sheet wrinkling rate is 15%–33%.

[0015] A cotton fiber cream paper base paper prepared by the above preparation method has an interlocking skeleton formed by long fiber interlocking pulp and short fiber pulp filled in the interlocking skeleton, so that the cotton fiber cream paper base paper takes into account strength, softness, bulk and liquid absorption performance.

[0016] Furthermore, the basis weight of the cotton fiber emulsion paper base paper is 14±0.5 g / m², the longitudinal dry tensile index is ≥8.0 N·m / g, the transverse dry tensile index is ≥3.0 N·m / g, the longitudinal wet tensile index is >1.0 N·m / g, the softness is 70 mN-78 mN, the bulk is 5.80 cm³ / g–6.20 cm³ / g, and the transverse liquid absorption height is ≥65 mm / (100s).

[0017] This invention does not add cotton fibers as a common auxiliary material to the wood pulp system. Instead, it adjusts the order in which cotton fibers participate in the fiber network formation process, allowing cotton fibers to first undertake the role of skeleton construction, and then short fibers to complete the filling and fineness adjustment. The process route has changed significantly, altering the existing treatment method of simultaneous mixing and pulping of various fibers in long and short fiber blends. This creates a synergistic relationship between cotton fibers, softwood pulp, and hardwood pulp, with skeleton construction followed by filling. The continuous process design focuses on the balance between the softness, toughness, lint control, and cream adsorption adaptability of the base paper, thereby improving the overall performance stability of the base paper.

[0018] By adopting the above technical solution, the present invention can also bring the following beneficial effects: 1. This invention discloses a method for preparing cotton fiber-containing emulsion paper base paper. By selecting cotton fibers of specific length, fineness, and amount, and allowing the cotton fibers to participate in the fiber network construction of the cotton fiber-containing emulsion paper base paper together with wood pulp components, the length of the cotton fibers is controlled at 1.0mm-1.5mm, and the micronaire value is controlled at 3.7-4.2. This avoids the difficulty in forming effective fiber bridging when the cotton fibers are too short, and also avoids pulp flocculation and decreased paper uniformity when the cotton fibers are too long. The amount of cotton fibers added is controlled at 1%-3%. After testing, the transverse tensile index of the cotton fiber-containing emulsion paper base paper is 3.53 N·m / g, the longitudinal tensile index is 8.92 N·m / g, and the longitudinal wet tensile index is 1.09 N·m / g, which are 2.83%, 12.11%, and 24.77% higher than those of conventional emulsion paper base paper, respectively. It has the advantages of reasonable fiber ratio, good paper toughness, significantly improved wet strength, and strong tear resistance.

[0019] 2. This invention discloses a method for preparing cotton fiber-containing latex paper base paper. The method involves pretreating cotton fibers with warm water, a penetrant, and a composite cellulase to obtain pretreated cotton fibers. This pretreated cotton fibers are fully swollen and have reduced rigidity before entering the subsequent desizing and beating processes, thereby reducing excessive cutting during beating. The pretreated cotton fibers undergo separate hydraulic desizing to disperse them into a cotton fiber dispersion slurry before the addition of softwood pulp. This reduces problems such as localized agglomeration, white spots, and uneven paper formation caused by incomplete dispersion of the pretreated cotton fibers. Subsequently, softwood pulp is added to the cotton fiber dispersion slurry. The process involves co-breaking and beating pretreated cotton fibers with softwood pulp to form a long-fiber interlocking pulp. The pretreated cotton fibers and softwood pulp long fibers intertwine in the long-fiber interlocking pulp to form an interlocking skeleton, enhancing the locking ability for subsequent short-fiber pulp. After pretreatment, the fibrillation rate of cotton fibers can reach 65%-70%, which is higher than the fibrillation level of ordinary cotton fibers (about 50%-55%). This is beneficial for forming a loose and porous base paper skeleton and reducing the risk of fiber shedding. The shedding rate can be reduced to ≤0.05%. It has the advantages of sufficient cotton fiber dispersion, stable beating process, less excessive fiber cutting, low risk of shedding, and stable base paper skeleton.

[0020] 3. This invention discloses a method for preparing cotton fiber-containing emulsion paper base paper. After the long fiber interlocking pulp is formed, short fiber pulp formed from hardwood pulp is added to the long fiber interlocking pulp for mixing. This allows the short fiber pulp to fill the interlocking skeleton formed by the long fiber interlocking pulp, which is used to supplement the paper's fineness and improve the paper's uniformity. By coordinating the pulp flow rate, white water return flow rate, leveling mill treatment, pulp beating degree in the pulping tank, production aids, and creping process, the resulting cotton fiber-containing emulsion paper base paper balances softness, bulk, and transverse liquid absorption height. The bulk of the cotton fiber-containing emulsion paper base paper is 5.88 cm³ / g, which is 3.73% higher than that of conventional emulsion paper base paper. The lateral liquid absorption height is 69mm / 100s, which is 5.80% higher than that of conventional cream paper base paper. The softness is 75mN, which is 9.33% lower than that of conventional cream paper base paper. The lower softness value indicates that the paper feels softer. The natural hollow structure and softness of cotton fibers help to make the roughness of the base paper Ra≤2.5μm, presenting a velvety texture, and reducing the dependence on a large amount of chemical softeners. This reduces the risk of decreased fiber bonding and skin irritation caused by excessive chemical softeners. It has the advantages of balancing strength and softness, good cream absorption adaptability, fine and uniform paper, good velvety feel, and suitability for use in maternal and infant care and sensitive skin scenarios. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart of a method for preparing a cotton fiber latex-based paper base paper mentioned in this invention; Detailed Implementation

[0023] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this invention, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0026] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0027] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details. Example 1

[0028] like Figure 1 As shown, the present invention provides a method for preparing cotton fiber emulsion paper base paper, comprising the following steps: S1. Selecting raw materials; Based on the total mass of fiber raw materials, cotton fiber and wood pulp components were selected. The cotton fiber used was Yinshan brand cotton pulp board, which was made from Xinjiang long-staple cotton. Xinjiang long-staple cotton fibers are longer, stronger, and have fewer impurities. After pretreatment, they can form a relatively stable fiber bond structure with the wood pulp fibers. The wood pulp components included softwood pulp and hardwood pulp. The softwood pulp used was Moon brand commercial softwood pulp, and the hardwood pulp used was Goldfish brand commercial hardwood pulp. The cotton fiber length was 1.0mm-1.5mm, and the micronaire value was 3.7-4. 2. The amount of cotton fiber added is 1%-3% of the total dry pulp mass. This prevents the cotton fiber from being too short to form effective fiber bridging, and also prevents the cotton fiber from being too long to cause pulp flocculation and affect paper uniformity. The low proportion of cotton fiber added can reduce the problem of reduced paper softness and increased cost while providing toughness and a velvety feel. The ratio of long fiber pulp to short fiber pulp is set at 25:75, so that softwood pulp provides skeletal support, while hardwood pulp fills the pores and improves the fineness of the paper.

[0029] S2, pretreated cotton fibers; Yinshan brand cotton pulp board was placed in 50℃ warm water, and a penetrant of 0.3% of the cotton fiber mass was added. The penetrant was fatty alcohol polyoxyethylene ether. After soaking for 1.5 hours, a compound cellulase of 0.1% of the cotton fiber mass was added, and the mixture was kept at 50℃ for 1.5 hours. Then, the temperature was raised to 75℃ and kept at 75℃ for 15 minutes for inactivation treatment to obtain pretreated cotton fibers.

[0030] By gently pretreating cotton fibers with warm water, penetrants, and compound cellulase, the cotton fibers can be rapidly swollen and their rigidity reduced, providing a foundation for subsequent mechanical dispersion and pulping. This reduces excessive cutting of cotton fibers during the subsequent pulping process and helps improve the flocculant effect of cotton fibers, making it easier for cotton fibers to combine with wood pulp fibers in the subsequent fiber network construction.

[0031] S3, separate cotton fibers; The pretreated cotton fibers were individually hydraulically dispersed at a concentration of 3.5% for 8 minutes to form uniformly dispersed single fibers, resulting in a cotton fiber dispersion slurry. By fully dispersing the pretreated cotton fibers before adding softwood pulp, local agglomeration caused by incomplete dispersion of cotton fibers during subsequent mixing, disintegration, and refining can be avoided, reducing the risk of white spots and decreased uniformity in the finished paper. In this process, the pretreated cotton fibers first form a cotton fiber dispersion slurry, which also provides a dispersion basis for the subsequent interlocking skeleton formation with the long fibers of softwood pulp.

[0032] S4, co-processing cotton fibers and softwood pulp; Under the condition of maintaining the hydraulically dispersed state of the cotton fiber dispersion slurry, Moon Brand commercial softwood pulp was slowly added to the cotton fiber dispersion slurry, allowing the pretreated cotton fibers and softwood pulp to mix evenly before being broken down. The broken-down slurry was then pumped into the long fiber pre-beating slurry tank, where it was ground by a single disc mill, and then pumped into the long fiber post-beating slurry tank to obtain a long fiber interlocked slurry; the beating degree of the long fiber interlocked slurry was 26°SR. The pretreated cotton fibers and softwood pulp long fibers were jointly broken down and beaten under a continuous dispersion state, causing the pretreated cotton fibers and softwood pulp long fibers to interlock and form an interlocked skeleton. This treatment sequence allows the cotton fibers to primarily undergo flocculentization during beating, reducing excessive cutting, and ensuring that the cotton fibers are not merely a regular slurry component but instead participate in the fiber skeleton construction. The long fiber interlocked slurry enhances the locking ability of subsequent short fiber slurries, thereby reducing the risk of fiber shedding.

[0033] S5, processing hardwood pulp; Goldfish brand commercial hardwood pulp is fed into a short-fiber hydraulic pulper for disintegration, then pumped into a pre-beating pulp tank. After being processed by a de-fibering machine, it is pumped into a post-beating pulp tank to obtain short-fiber pulp. The beating degree of the short-fiber pulp is 24°SR. The short-fiber pulp is used to fill the interlocking skeleton formed by the long-fiber interlocking pulp in the subsequent mixing process, supplementing the paper's fineness and improving the paper's uniformity. By allowing the short-fiber pulp to participate in the mixing process after the long-fiber interlocking pulp has been formed, the short-fiber pulp can be transformed from a general mixed pulp component into a fiber component that fills the interlocking skeleton, which is beneficial for forming a paper fiber structure that balances strength, fineness, and soft touch.

[0034] S6, Slurry preparation; After the long fiber interlocking slurry and the short fiber slurry are formed separately, the long fiber interlocking slurry and the short fiber slurry are pumped into the mixing tank at a ratio of 25:75 for mixing, so that the short fiber slurry is added and filled into the interlocking skeleton after the long fiber interlocking slurry is formed. After the interlocked fiber pulp and short fiber pulp enter the mixing tank, they are treated by a leveling mill and then pumped into the forming tank. The freeness of the pulp in the forming tank is 28°SR. During the mixing and forming processes, the white water return flow rate is adjusted to regulate the fine fiber content in the pulp in the forming tank. Wet-end chemicals are added during the forming process, including a polyamide epichlorohydrin resin-type wet strength agent with a solid content of 12.5%, added at a rate of 20 kg / t. The polyamide epichlorohydrin resin-type wet strength agent can synergistically bond the fiber structure in the short fiber fragments and long fiber interlocked pulp, improve the bonding strength of the paper fiber structure, and improve the wet strength of the cotton fiber-containing emulsion paper base paper. During the use of production auxiliaries, one or more of dispersants and defoamers can also be selected. The dispersant is used to improve the dispersion state of the fibers in the pulp, and the defoamer is used to reduce foam during pulp transportation and forming.

[0035] S7. Copying and wrinkling; The pulp from the pulping tank is pumped into the headbox and then into the tissue paper machine for forming, pressing, and drying. After being dried to 65% dryness by an air hood and Yankee drying cylinder, the paper is creped by a carbon steel doctor blade that is closely attached to the surface of the drying cylinder. The creping angle is set to 80°-90°. The paper is then wound and slit to obtain cotton fiber cream paper base paper. When creping the paper, a titanium alloy doctor blade is used as needed. The creping rate of the paper reaches 15%-33%.

[0036] To evaluate the key properties of cotton fiber-containing cream paper base paper, a transverse comparison was made between the cotton fiber-containing cream paper base paper prepared in this embodiment and conventional cream paper base paper. The test indicators included transverse liquid absorption height, softness, dry strength, wet strength, and bulk. The basis weight of the standard sample and the cream paper base paper of this embodiment was converted to a single-layer basis weight of 14.0 ± 0.5 g / m². The test results are as follows: ; The test results above show that, compared with conventional cream paper base paper, the cotton fiber-containing cream paper base paper prepared in this embodiment has improved in terms of dry transverse tensile index, dry longitudinal tensile index, wet longitudinal wet tensile index, bulk, and transverse liquid absorption height. Specifically, the dry transverse tensile index increased by 2.83%, the dry longitudinal tensile index increased by 12.11%, the wet longitudinal wet tensile index increased by 24.77%, the transverse liquid absorption height increased by 5.80%, and the softness value decreased by 9.33%. Since the decrease in the softness value indicates that the paper feels softer, this embodiment can improve the soft touch of the cream paper base paper while improving strength and liquid absorption performance.

[0037] Meanwhile, the longitudinal tensile index of the cotton fiber-containing emulsion paper base paper reached 8.92 N·m / g, the transverse tensile index reached 3.53 N·m / g, and the longitudinal wet tensile index reached 1.09 N·m / g. This indicates that the fiber bonding structure formed between cotton fibers and wood pulp fibers can improve the dry and wet strength of the base paper, solving the problem of the emulsion paper base paper being easily torn. The softness of the cotton fiber-containing emulsion paper base paper is 75 mN, lower than the 82 mN of conventional emulsion paper base paper, indicating that the softness of cotton fibers can improve the soft touch of the base paper and give it a better velvety feel. The paper's bulk reached 5.88 cm³ / g, and its transverse liquid absorption height reached 69 mm / 100 s, indicating that the base paper skeleton formed by the combination of long-fiber interlocking pulp and short-fiber pulp has good looseness and liquid absorption capacity, which is conducive to the uniform penetration and adhesion of the subsequent cream coating. The processing sequence of first dispersing cotton fibers, then forming an interlocking skeleton with softwood pulp, and finally filling it with short-fiber pulp helps to reduce the risk of fiber shedding and lint, and reduces the dependence on a large amount of chemical softeners, making the resulting cotton fiber cream paper base paper more suitable for use in maternal and infant care, facial cleansing, and sensitive skin scenarios.

[0038] In summary, this invention pre-treats and separately hydraulically decomposes cotton fibers, then co-crushes and beats them with softwood pulp to form a long-fiber interlocking pulp. Subsequently, short-fiber pulp is added after the long-fiber interlocking pulp is formed and mixed with it. This allows cotton fibers to participate in the construction of the interlocking framework rather than simply being a component of the pulp. The short-fiber pulp then fills the interlocking framework. This invention has the advantages of good paper toughness, synergistic softness and velvety feel, low risk of lint shedding, and good adaptability to cream adsorption.

[0039] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a cotton fiber latex-based paper base, characterized in that, The steps include the following: S1. Select raw materials. Based on the total mass of fiber raw materials, select cotton fiber and wood pulp components. The cotton fiber is selected from Xinjiang long-staple cotton pulp board. The length of the cotton fiber is 1.0mm-1.5mm and the micronaire value is 3.7-4.

2. The amount of cotton fiber added is 1%-3%. The wood pulp components include softwood pulp and hardwood pulp. The softwood pulp accounts for 25%-40% of the mass of the wood pulp components, and the hardwood pulp accounts for 60%-75% of the mass of the wood pulp components. Based on the total mass of oven-dry pulp, the amount of production aids added is 0.1%-1%. The production aids include one or more of wet strength agents, dispersants, and defoamers. S2. Pre-treatment of cotton fibers: The cotton fibers are placed in warm water at 45℃-55℃, and a penetrant of 0.2%-0.4% by weight of the cotton fibers is added for 1h-1.5h. Then, a compound cellulase of 0.05%-0.15% by weight of the cotton fibers is added, and the mixture is kept at 48℃-52℃ for 1h-2h. Subsequently, the temperature is raised to 70℃-80℃ and kept at 70℃-80℃ for 10min-15min for inactivation treatment to obtain pre-treated cotton fibers, so that the cotton fibers swell and reduce rigidity before entering the subsequent desizing and pulping processes. S3. Separately disperse cotton fibers. The pretreated cotton fibers are separately hydraulically dispersed at a concentration of 3%-4% for 5-10 minutes. This allows the pretreated cotton fibers, which have been swollen and have reduced rigidity, to disperse into a cotton fiber dispersion slurry before the softwood pulp is added. This reduces the local agglomeration of the pretreated cotton fibers during the subsequent mixing, disintegration, and pulping process with the softwood pulp. S4. Co-processing cotton fibers and softwood pulp: Under the condition that the cotton fiber dispersion pulp is kept in a hydraulically disintegrated state, softwood pulp is added to the cotton fiber dispersion pulp, so that the pre-treated cotton fibers and softwood pulp are mixed in a continuously dispersed state, and then broken down and pulped to form a long fiber interlocking pulp. The freeness of the long fiber interlocking pulp is 24°SR-30°SR. In the long fiber interlocking pulp, the pre-treated cotton fibers and softwood pulp long fibers are interwoven to form an interlocking skeleton. S5. Processing hardwood pulp: Hardwood pulp is fed into a short fiber hydraulic pulper for pulping, then pumped into a pre-beating pulp tank for short fiber pulping. After being processed by a de-beating machine, it is pumped into a post-beating pulp tank to obtain short fiber pulp. The degree of beating of the short fiber pulp is 22°SR-26°SR to ensure that the short fiber pulp maintains its dispersion and filling capacity. S6. Slurry preparation: After the short fiber slurry is formed, it is added to the long fiber interlocking slurry for slurry preparation, so that the short fiber slurry fills the interlocking skeleton formed by the long fiber interlocking slurry. During the slurry preparation or slurry formation process, production aids are added to obtain the slurry in the slurry tank. S7. Forming and creping: The pulp from the pulping tank is pumped into the headbox and then into the tissue paper machine for forming, pressing and drying. The paper sheet dried to a dryness of 55%-85% is creped by a doctor blade, then wound and slit to obtain cotton fiber cream paper base paper.

2. The method for preparing a cotton fiber latex-based paper base paper according to claim 1, characterized in that: In step S3, the pretreated cotton fibers are individually hydraulically dispersed to form uniformly dispersed single fibers, so as to avoid the cotton fibers not being completely dispersed and forming agglomerates during the subsequent pulping process.

3. The method for preparing a cotton fiber latex-based paper base paper according to claim 1, characterized in that: In step S4, the softwood pulp is slowly added to the cotton fiber dispersion pulp, so that the pretreated cotton fiber and softwood pulp are mixed evenly and then broken down. Then it is sent to the long fiber pre-pulping tank, and after being pulped by a refiner, it is sent to the long fiber post-pulping tank.

4. The method for preparing a cotton fiber latex-based paper base paper according to claim 1, characterized in that: In step S4, the freeness of the long-fiber interlocking pulp is 26°SR-28°SR, so that the pretreated cotton fibers and softwood pulp long fibers form a fiber bond structure and reduce excessive cutting of long fibers.

5. The method for preparing a cotton fiber-containing emulsion paper base paper according to claim 1, characterized in that: In step S1, the cotton fiber is made from Yinshan brand cotton pulp board, which is made from Xinjiang long-staple cotton. In step S2, the penetrant is fatty alcohol polyoxyethylene ether, and the composite cellulase is added after the penetrant soaking treatment.

6. The method for preparing a cotton fiber-containing emulsion paper base paper according to claim 1, characterized in that: In step S6, the flow rates of the long-fiber interlocking pulp and the short-fiber pulp are adjusted so that the long-fiber interlocking pulp and the short-fiber pulp are mixed in the mixing tank at a mass ratio of 22-28:78-72. This allows the long-fiber interlocking pulp to provide strength support while the short-fiber pulp supplements the paper's fineness and uniformity.

7. The method for preparing a cotton fiber emulsion-based paper base paper according to claim 6, characterized in that: In step S6, during the mixing process of long fiber interlocked slurry and short fiber slurry in the mixing tank, the white water return flow rate is adjusted to regulate the fine fiber content in the slurry entering the pulping tank. After the short fiber slurry and long fiber interlocked slurry enter the mixing tank, they are treated by a homogenizing mill and then pumped into the pulping tank. The freeness of the slurry in the pulping tank is 25°SR-30°SR.

8. The method for preparing a cotton fiber-containing emulsion paper base paper according to claim 1, characterized in that: In step S6, the production aids include a wet strength agent, which is a polyamide epichlorohydrin resin with a solid content of 12.5% ​​and an addition amount of 20 kg / t, to enhance the bonding strength between the short fiber pulp and the long fiber interlocking pulp. In step S7, the doctor blade is a titanium alloy doctor blade or a carbon steel doctor blade, and the wrinkling rate of the paper sheet is 15%–33%.

9. A cotton fiber-containing emulsion paper base paper prepared by the method for preparing cotton fiber emulsion paper base paper according to any one of claims 1-8, characterized in that: The cotton fiber emulsion paper base paper has an interlocking skeleton formed by long fiber interlocking pulp and short fiber pulp filled in the interlocking skeleton, so that the cotton fiber emulsion paper base paper takes into account strength, softness, bulk and liquid absorption performance.

10. The cotton fiber-containing emulsion paper base paper according to claim 9, characterized in that: The basis weight of the cotton fiber emulsion paper base paper is 14±0.5 g / m², the longitudinal dry tensile index is ≥8.0 N·m / g, the transverse dry tensile index is ≥3.0 N·m / g, the longitudinal wet tensile index is >1.0 N·m / g, the softness is 70 mN-78 mN, the bulk is 5.80 cm³ / g–6.20 cm³ / g, and the transverse liquid absorption height is ≥65 mm / (100s).

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