Manufacturing method of cream base paper with high cream bearing capacity

Abstract

The invention relates to a manufacturing method of cream base paper with high cream bearing capacity, and belongs to the field of papermaking. According to the main technical scheme, long fibers (one or more of cotton pulp, softwood pulp or bamboo pulp, containing commercial pulp and pretreated pulp) are crushed and then pass through two disc mills connected in series under the power of 35-80 kWh / t, and long-fiber-beaten pulp with the beating degree of 24-36 degrees SR and the wet weight of 8.1-12.5 g is obtained; broadleaf wood short fibers and broken paper are respectively crushed and are only subjected to defibering treatment. Regulating and controlling the pulp preparation flow to mix the long-fiber beaten pulp, the short-fiber pulp and the broken pulp according to the mass ratio of (10-30): (84-65): (20-0), performing uniform grinding treatment with the power of 15-30kwh / t until the beating degree is 25-50 degrees SR, and dynamically regulating the white water reflux in the process. And wrinkling by adopting a ceramic or carbon steel scraper (the wrinkling ratio is 18-25%), and coiling and slitting to obtain the cream base paper. According to the method, through collaborative optimization of the fiber ratio, pulping and wrinkling, the fiber binding force and the three-dimensional structure are remarkably enhanced, the addition amount of the finished cream is larger than 2.5 g / m < 2 >, the addition rate is larger than 15%, the one-hour moisture retention is larger than 50%, and synchronous improvement of high bearing capacity and durability is achieved.

Description

Technical Field

[0001] The invention belongs to the field of papermaking and relates to a method for manufacturing cream base paper with high cream carrying capacity. Background Art

[0002] The core of the performance of sanitary tissue lies in the synergistic balance of water absorption, softness, strength and bulk, which is essentially controlled by fiber properties, chemical additives and papermaking process. Depending on the type of tissue, there will be a specific formula of short fiber and long fiber ratio. As a functional coating substrate, the microstructural characteristics of cream base paper directly determine the cream loading efficiency, moisturizing durability and usage intensity of the final product. The current industry generally adopts the process route of "short fiber main body-long fiber reinforcement" fiber system (hardwood pulp: softwood pulp ≈7:3~8:2) combined with wet strength agent addition (5-30kg / t). However, this system has inherent limitations:

[0003] (1) Structural contradiction: Although low beating strength (<35°SR) can maintain fiber length and brooming rate and build a high-pore network to increase the emulsion loading capacity, it leads to insufficient hydrogen bonding points between fibers and limited wet tensile strength;

[0004] (2) Process defects: Homogenization beating causes excessive cutting of the long fiber skeleton, low short fiber filling efficiency, and significantly reduces the emulsion retention rate;

[0005] (3) Chemical dependence: The addition of PAE type wet strength agent compensates for the strength gap, but the more wet strength agent is added, the more obvious the water resistance of the paper is and the lower the water absorption and moisture retention is.

[0006] Therefore, it is urgent to reconstruct the fiber network through step-by-step regulation of fiber ratio, differentiated beating strategies and white water circulation optimization to break through the synergistic bottleneck of high cream load, wet strength and moisturizing properties. Summary of the Invention

[0007] In view of this, the present invention provides a method for manufacturing a cream base paper with high cream loading capacity. Starting from the fiber properties and conventional high-speed crescent paper machine technology, improvements are proposed to improve the cream loading capacity while achieving the key physical strength of the standard sample cream paper.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for manufacturing a cream base paper with a high cream loading capacity, characterized by comprising the following steps:

[0010] (1) Preparation of fiber raw materials: providing long fibers, short fibers and broken paper;

[0011] (2) beating treatment: After the long fibers are crushed, they are beaten by two disc refiners connected in series at a power of 35-80 kWh / t to obtain a long fiber beating pulp with a beating degree of 24-36° SR and a wet weight of 8.1-12.5 g; after the short fibers and broke are crushed, they are only debonded to obtain short fiber pulp and broke pulp;

[0012] (3) pulping: mixing the long fiber pulp, short fiber pulp and broke pulp in a mass ratio of (10-30): (84-65): (20-0), and adjusting the amount of white water return during the pulping and pulping process;

[0013] (4) Slurry refining: The mixed pulp is subjected to a slurry refining process at a power of 15-30 kwh / t to obtain a pulp with a beating degree of 25-50°SR;

[0014] (5) Papermaking: the pulp is papered into a wet paper web on a high-speed crescent-shaped toilet paper machine;

[0015] (6) Wrinkling and post-processing: The wet paper web is wrinkled using a ceramic or carbon steel scraper with a wrinkling rate of 18-25%, followed by winding and slitting to obtain the cream base paper;

[0016] (7) The physical performance index of the cream base paper produced by the manufacturing method (converted into a single layer) reaches a quantitative value of 10-20 g / m 2 , longitudinal dry tensile index > 7.0N·m / g, transverse dry tensile index > 2.9N·m / g, longitudinal wet tensile index > 2.5N·m / g, softness < 95mN, bulk > 6.60m 3 / g, lateral liquid absorption height>75mm / (100s);

[0017] (8) The cream loading of the corresponding cream paper produced after the cream base paper is coated with cream is greater than 2.5g / m 2 , cream addition rate>15%, 1h moisturizing>50%.

[0018] Preferably, the long fibers are selected from one or more of cotton pulp, coniferous wood pulp and bamboo pulp.

[0019] Preferably, the staple fibers are hardwood pulp.

[0020] Preferably, the long fibers and short fibers include commercial pulp and pretreated pulp; wherein the pulp pretreatment methods include oxidation treatment and enzyme treatment.

[0021] Preferably, in the slurry preparation step, wet-end chemicals are also added, and the wet-end chemicals include a bactericide, a softener and a wet strength agent; the wet strength agent is polyamide epichlorohydrin resin (PAE).

[0022] A cream base paper with high cream loading capacity, characterized in that it is made by the manufacturing method described in any one of the above conditions.

[0023] The physical performance index of the cream base paper (converted into a single layer) reaches a quantitative value of 10-20g / m 2 , longitudinal dry tensile index > 7.0N·m / g, transverse dry tensile index > 2.9N·m / g, longitudinal wet tensile index > 2.5N·m / g, softness < 95mN, bulk > 6.60m 3 / g, horizontal liquid absorption height>75mm / (100s).

[0024] The cream loading of the corresponding cream paper produced after the cream base paper is coated with cream is greater than 2.5g / m 2 , cream addition rate>15%, 1h moisturizing>50%.

[0025] As can be seen from the above technical solutions, compared to existing technologies, the present invention provides a method for manufacturing cream-based paper with a high cream-bearing capacity, which has the following beneficial effects: It addresses the challenges of "high load-bearing capacity" and "wet strength / moisture retention" at the fiber level. Through step-by-step fiber ratio control (independent processing of long fibers, short fibers, and broke), differentiated beating (only beating long fibers, moderately cutting and strengthening entanglement), and optimized white water circulation (dynamically controlling the distribution of fine fibers), the base paper microstructure is reconstructed, overcoming the synergistic challenges of high cream-bearing capacity and mechanical strength. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0027] The fine fiber content of cream base paper is determined according to GB / T 29779-2013.

[0028] The moisturizing properties of cream paper were tested by oven drying at 60°C for 1, 2, and 3 hours. The paper was then placed in a desiccator, cooled to room temperature, and weighed. The moisturizing properties, cream dosage, and cream addition rate were calculated using the following formulas.

[0029]

[0030] Cream addition amount = cream paper mass - base paper mass

[0031]

[0032] Example 1

[0033] (1) After Moon brand commercial softwood pulp was pulverized, it was refined by a single disc refiner at a power of 55 kWh / t to obtain a long-fiber pulp with a beating degree of 25°SR and a wet weight of 11.0 g.

[0034] (2) Goldfish brand commercial hardwood pulp and broke paper are only debonded after shredding to obtain short fiber pulp and broke paper pulp;

[0035] (3) The long fiber pulp, short fiber pulp and damaged paper pulp are mixed in a mass ratio of 15:80:5, and the amount of white water return is adjusted during the pulping and pulping process;

[0036] (4) The mixed slurry was processed by uniform grinding under the condition of power of 20kwh / t to obtain a beating degree of 28 ° SR pulping;

[0037] (5) The wet end chemicals added include PAE type low chlorine wet strength agent 1# with a solid content of 15.0% and an addition amount of 15 kg / t;

[0038] (6) The pulp is formed into a wet paper web on a high-speed crescent-shaped toilet paper machine; the wet paper web is wrinkled using a ceramic scraper with a wrinkling rate of 20%, and then rolled and cut to obtain the cream base paper.

[0039] Example 2

[0040] (1) After the Rainbow Fish brand commercial softwood pulp was crushed, it was passed through two disc refiners running in series at a power of 40 kWh / t to obtain a long-fiber pulp with a beating degree of 28°SR and a wet weight of 9.0 g.

[0041] (2) After shredding, the Goldfish brand commercial hardwood pulp and broken paper were only decomposed to obtain short fiber pulp and broken paper pulp; among them, 20% of the Goldfish brand commercial hardwood pulp was pretreated with cellulase, and the enzyme treatment conditions were pulp concentration 10%, temperature 55°C, pH 5.0, and time 2h.

[0042] (3) The long fiber pulp, short fiber pulp and damaged paper pulp are mixed in a mass ratio of 20:70:10, and the amount of white water return is adjusted during the pulping and pulping process;

[0043] (4) The mixed slurry was subjected to a uniform grinding process at a power of 30 kwh / t to obtain a slurry with a beating degree of 35°SR;

[0044] (5) The wet end chemicals added include PAE wet strength agent 2# with a solid content of 12.5% ​​and an addition amount of 20 kg / t;

[0045] (6) The pulp is sheeted into a wet paper web on a high-speed crescent-shaped toilet paper machine; the wet paper web is wrinkled using a carbon steel scraper with a wrinkling rate of 22%, and then rolled and slit to obtain the cream base paper.

[0046] Example 3

[0047] (1) Basi brand commercial bamboo pulp and Yongfeng brand commercial softwood pulp were added in a ratio of 9:1 and passed through two disc refiners running in series with power of 45 kWh / t and 40 kWh / t respectively to obtain a long fiber pulp with a beating degree of 32°SR and a wet weight of 8.6 g; the Yongfeng brand commercial softwood pulp was TEMPO-oxidized and had a carboxyl content of 0.8 mmol / g;

[0048] (2) Goldfish brand commercial hardwood pulp and broke paper are only debonded after shredding to obtain short fiber pulp and broke paper pulp;

[0049] (3) The long fiber pulp, short fiber pulp and damaged paper pulp are mixed in a mass ratio of 12:75:13, and the amount of white water return is adjusted during the pulping and pulping process;

[0050] (4) The mixed slurry was subjected to a uniform grinding process at a power of 25 kwh / t to obtain a slurry having a beating degree of 47°SR;

[0051] (5) The wet end chemicals added include PAE wet strength agent 3# with a solid content of 12.5% ​​and an addition amount of 25 kg / t;

[0052] (6) The pulp is formed into a wet paper web on a high-speed crescent-shaped toilet paper machine; the wet paper web is wrinkled using a carbon steel scraper with a wrinkling rate of 18%, and then rolled and cut to obtain the cream base paper.

[0053] In order to better compare the key performance indicators of the cream base paper, such as lateral liquid absorption height, softness, strength (dry / wet) and bulk, as well as the corresponding moisturizing properties of the cream paper, the basis weight of the standard sample and the cream base paper of the embodiment of the present invention is 14.0±0.5g / m 2 The creams in the examples are of the same kind and the roller coating conditions are the same.

[0054] The various properties of the cream base paper and the corresponding cream paper produced by the methods described in Examples 1-3 of the present invention were measured in accordance with GB / T 20808-2022, and the results are shown in the table below. The results show that the various properties of the base paper of Examples 1-3 and the corresponding cream paper are similar to or better than those of the standard sample. Under the same roller coating conditions, the base paper of Examples 1-3 has significantly improved cream absorption and retention rate. The amount and addition rate of cream added are: Example 3 > Example 2 > Example 1 ≈ Standard sample. While maintaining controllable costs, the moisture-locking and moisturizing properties of the cream paper are greatly improved.

[0055]

Claims

1. A method for manufacturing a cream base paper with high cream loading capacity, characterized in that: The following steps are involved: (1) Preparation of fiber raw materials: providing long fibers, short fibers and broken paper; (2) beating treatment: After the long fibers are crushed, they are beaten by two disc refiners connected in series at a power of 35-80 kWh / t to obtain a long fiber beating pulp with a beating degree of 24-36° SR and a wet weight of 8.1-12.5 g; after the short fibers and broke are crushed, they are only debonded to obtain short fiber pulp and broke pulp; (3) pulping: mixing the long fiber pulp, short fiber pulp and broke pulp in a mass ratio of (10-30): (84-65): (20-0), and adjusting the amount of white water return during the pulping and pulping process; (4) Slurry refining: The mixed pulp is subjected to a slurry refining process at a power of 15-30 kwh / t to obtain a pulp with a beating degree of 25-50°SR; (5) Papermaking: The pulp is papered into a wet paper web on a high-speed crescent-shaped toilet paper machine. (6) Wrinkling and post-processing: The wet paper web is wrinkled using a ceramic or carbon steel scraper with a wrinkling rate of 18-25%, followed by winding and slitting to obtain the cream base paper; (7) The physical performance index of the cream base paper produced by the manufacturing method (converted into a single layer) reaches a quantitative value of 10-20 g / m 2 , longitudinal dry tensile index > 7.0N·m / g, transverse dry tensile index > 2.9N·m / g, longitudinal wet tensile index > 2.5N'm / g, softness < 95mN, bulk > 6.60m 3 / g, lateral liquid absorption height>75mm / (100s); (8) The amount of cream added to the corresponding cream paper produced after the cream base paper is coated with cream is greater than 2.5g / m 2 , cream addition rate>15%, 1h moisturizing>50%.

2. The method for manufacturing a cream base paper with high cream loading capacity according to claim 1, characterized in that: The long fibers are selected from one or more of cotton pulp, coniferous wood pulp and bamboo pulp.

3. The method for manufacturing a cream base paper with high cream loading capacity according to claim 1, characterized in that: The short fibers are hardwood pulp.

4. The method for manufacturing a cream base paper with high cream loading capacity according to claim 1, characterized in that: The long fibers and short fibers include commercial pulp and pretreated pulp.

5. The method for manufacturing a cream base paper with high cream loading capacity according to claim 4, characterized in that: The pulp pretreatment methods include oxidation treatment and enzyme treatment.

6. The method for manufacturing a cream base paper with high cream loading capacity according to claim 1, characterized in that: In the slurry preparation step, wet-end chemicals are also added, and the wet-end chemicals include fungicides, softeners and wet strength agents.

7. The method for manufacturing a cream base paper with high cream loading capacity according to claim 6, characterized in that: The wet strength agent is polyamide epichlorohydrin resin (PAE).

8. A cream base paper with high cream loading capacity, characterized in that: Prepared by the manufacturing method according to any one of claims 1 to 7.

9. The high cream-bearing capacity cream base paper according to claim 8, characterized in that: The physical performance index of the cream base paper (converted into a single layer) reaches a quantitative value of 10-20g / m 2 , longitudinal dry tensile index > 7.0N·m / g, transverse dry tensile index > 2.9N·m / g, longitudinal wet tensile index > 2.5N·m / g, softness < 95mN, bulk > 6.60m 3 / g, horizontal liquid absorption height>75mm / (100s).

10. The cream base paper with high cream loading capacity according to claim 9, characterized in that: The amount of cream added to the corresponding cream paper produced after the cream base paper is coated with cream is greater than 2.5g / m 2 , cream addition rate>15%, 1h moisturizing>50%.

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