A low-bulk tampon and method of making same

Abstract

The application discloses a low-swelling sanitary tampon and a preparation method thereof, and belongs to the technical field of sanitary products. The application makes the fiber structure more compact by pretreating the cotton fibers, loses part of the flexibility, and preliminarily reduces the swelling of the cotton fibers. Then, the surface of the cotton fibers is etched by plasma to expose more active groups, and the interface bonding strength of the pretreated cotton fibers and the bio-based adhesive is improved. Furthermore, the three-dimensional network formed by the adhesive strongly binds the fibers, the pressing and microwave shaping processes are combined, the adhesive forms a stable three-dimensional network among the fibers, the whole tampon body is locked in a preset compressed state, the high-quality stability and smooth use of the tampon in a dry state are ensured, once the menstrual blood is contacted, the adhesive bonding force is destroyed by the menstrual blood, the binding among the cotton fibers is released, and the tampon body is fully swelled, so that the good absorption capacity is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sanitary products, in particular to a low-swelling sanitary tampon and a preparation method thereof. BACKGROUND

[0002] As an internal female sanitary product, sanitary tampon has been favored by more and more consumers due to its convenience and comfort in use. Traditional sanitary tampon is mainly made of high water-absorbing materials such as cotton fibers, and its core function is to prevent leakage by absorbing menstrual blood. However, the sanitary tampon products in the prior art still have some inherent defects, which affect the user experience and product performance.

[0003] Firstly, a significant problem of traditional sanitary tampon is its uncontrollable over-swelling after absorbing liquid. As the main absorbing material, cotton fiber has a natural physical property that it swells rapidly after contacting liquid. Although this swelling is the basis for achieving the absorption function, if the swelling rate is too high or the swelling form is uneven, it will cause two main problems: one is that it may cause discomfort to the user during menstruation; the other is that the dramatic change in form of the tampon before it reaches the saturated absorption may damage its fit with the vaginal wall, forming a gap, which leads to side leakage or leakage, which is contrary to the original intention of product design.

[0004] Secondly, in order to control the swelling and maintain the compressed form of the tampon before insertion, traditional process usually relies on high-pressure physical compression. However, the structure formed by this simple physical compression may rebound due to changes in environmental temperature and humidity during storage and transportation, resulting in unstable product size and affecting its smooth insertion. More importantly, once it comes into contact with liquid, this physical restraint is easily broken and cannot effectively inhibit subsequent over-swelling.

[0005] Although the industry has tried to guide the flow of liquid and try to manage the swelling form by changing the weave pattern of the tampon or external pressure groove, etc., these improvement measures do not essentially change the swelling properties of the absorbing core material. SUMMARY

[0006] The main purpose of the present application is to provide a low-swelling sanitary tampon and a preparation method thereof. By pretreating the cotton fibers to preliminarily reduce their swelling, and then applying a bio-based adhesive between the single-layer cotton fibers to effectively bond the cotton fibers and form a tightly locked overall structure, the sanitary tampon made thereby can maintain its structural integrity after absorbing liquid and is less likely to leak, thereby improving the user experience of the product.

[0007] To achieve the above purpose, the present application provides a preparation method of a low-swelling sanitary tampon, comprising the following steps:

[0008] S1, carding the pretreated cotton fibers, after carding, stacking into single layer of cotton fibers, coating a bio-based adhesive on the single layer of cotton fibers, then covering another single layer of cotton fibers to obtain double layer of cotton fibers, stacking the double layer of cotton fibers to obtain a cotton web layer, wrapping the cotton web layer with non-woven fabric, and then pressing into a strip-shaped fiber layer;

[0009] S2, fixing a cotton thread at a center part of the strip-shaped fiber layer, with the tail end of the cotton thread exposed outside the strip-shaped fiber layer by 10-20 cm, then curling the strip-shaped fiber layer to form a long strip cylindrical absorbent, and after being pressed and formed in a former, performing microwave heating treatment to obtain a cotton tampon body of the sanitary cotton tampon;

[0010] S3, compressing the cotton tampon body of the sanitary cotton tampon into a catheter to obtain a low-swelling sanitary cotton tampon.

[0011] Preferably, the preparation method of the pretreated cotton fibers in step S1 is as follows: immersing the cotton fibers in a sodium sulfate aqueous solution, taking out and drying, and then treating the obtained pretreated cotton fibers with plasma.

[0012] Further preferably, the concentration of the sodium sulfate aqueous solution is 20-30 wt%, and under the treatment of the sodium sulfate aqueous solution at this concentration, the cotton fibers can be shrunk and dehydrated by osmotic pressure, so that the fiber structure becomes more compact and loses part of the flexibility, and the swelling property of the cotton fibers can be preliminarily reduced, and then the surface of the cotton fibers is etched by plasma to expose more active groups, which is beneficial to improve the interfacial bonding strength between the modified adhesive and the pretreated cotton fibers.

[0013] Preferably, the grammage of the single layer of cotton fibers in step S1 is 12-16 g / m 2 .

[0014] Preferably, the preparation method of the bio-based adhesive in step S1 comprises the following steps:

[0015] immersing gelatin in cold water for swelling, then heating and dissolving, adding glycyrrhizin and formaldehyde aqueous solution, adjusting the pH to 4-6 after ultrasonic dispersion under nitrogen atmosphere, and then heating and reacting, and after the reaction is completed, removing the solvent by reduced pressure evaporation, and then spray drying the residue to obtain a gelatin compound; adding L-tryptophan to deionized water, adding acetic acid aqueous solution dropwise, adjusting the pH value to 5-6, and then adding the gelatin compound, polyvinyl alcohol, dialdehyde starch and hydroxyethyl cellulose, heating and stirring, and after the reaction is completed, cooling to obtain a bio-based adhesive.

[0016] Further preferably, the mass ratio of the gelatin, glycyrrhizin and formaldehyde aqueous solution is 2-5:1-3:6-10, and the concentration of the formaldehyde aqueous solution is 30-40 wt%.

[0017] Further preferably, the temperature of the heating reaction is 55-75 DEG C, and the reaction time is 3-5h.

[0018] Further preferably, the mass ratio of the L-tryptophan, the gelatin complex, the polyvinyl alcohol, the dialdehyde starch and the hydroxyethyl cellulose is 8-10:20-30:10-20:5-10:1-2.

[0019] Further preferably, the temperature of the heating and stirring is 60-75 DEG C, and the heating and stirring time is 1.5-2.5h.

[0020] The preparation of the bio-based adhesive of the present application is based on gelatin, polyvinyl alcohol and starch as the main body, first grafting glycyrrhizin in the gelatin molecules, so that glycyrrhizin is more uniformly dispersed and can be stably immobilized in the three-dimensional network structure of the adhesive, which is beneficial to exert its long-acting antibacterial performance, by introducing hydrophobic L-tryptophan into the adhesive system, on the one hand, the water resistance and dimensional stability of the adhesive can be improved; on the other hand, Schiff base reaction can also occur with dialdehyde starch, forming a three-dimensional network structure, which greatly enhances the cohesive force and mechanical strength of the adhesive, providing a physical basis for strongly binding cotton fibers and inhibiting their swelling in dry state.

[0021] When the bio-based adhesive is coated on the pretreated cotton fibers and then pressed and heated, it can be combined with the pretreated cotton fibers through covalent bond, anchoring the adhesive firmly on the fibers to form a tightly locked overall structure, finally giving the sanitary tampon good anti-swelling ability and dimensional stability.

[0022] Preferably, the grammage of the non-woven fabric in the step S1 is 30-50g / m 2 .

[0023] Preferably, the temperature of the microwave heating in the step S2 is 50-65 DEG C, and the time of the microwave heating is 2-8s.

[0024] Compared with the prior art, the present application has the following advantages:

[0025] (1) The application discloses a preparation method of low-swelling sanitary tampons, which comprises the following steps: firstly, modifying and pretreating cotton fibers, carding the pretreated cotton fibers to obtain a single-layer cotton fiber, coating a bio-based adhesive on the single-layer cotton fiber, and then stacking multiple layers to be pressed, curled, pressed and microwave-heat-treated to obtain a tampon body.

[0026] (2) The bio-based adhesive is prepared by selecting gelatin, polyvinyl alcohol and starch with biocompatibility as raw materials, reducing the irritation and allergy risk of users, and improving the safety of the product. DETAILED DESCRIPTION

[0027] For the sake of brevity, the articles used in the following examples are all commercially available products unless otherwise specified, and the methods used are all conventional methods unless otherwise specified. Example 1

[0028] A preparation method of low-swelling sanitary tampons comprises the following steps:

[0029] S1, carding pretreated cotton fibers, and then stacking the carded cotton fibers to obtain a single-layer cotton fiber with a grammage of 15 g / m 2 . A bio-based adhesive is coated on the single-layer cotton fiber, and then a single-layer cotton fiber is coated on the adhesive to obtain a double-layer cotton fiber. The double-layer cotton fiber is stacked to obtain a cotton web layer. The cotton web layer is wrapped with a non-woven fabric with a grammage of 40 g / m 2 , and then pressed into a strip-shaped fiber layer.

[0030] S2, fixing a cotton thread at the center of the strip-shaped fiber layer, with the tail end of the cotton thread exposed 15 cm outside the strip-shaped fiber layer, then rolling the strip-shaped fiber layer to form a long strip-shaped cylindrical absorbent, and then performing microwave heating treatment at 60℃ for 5s after compression molding in a former to obtain a cotton strip body of the sanitary tampon;

[0031] S3, compressing the cotton strip body of the sanitary tampon into a catheter to obtain a low-swelling sanitary tampon.

[0032] The preparation method of the pretreated cotton fiber in step S1 is as follows: the cotton fiber is immersed in a 25wt% sodium sulfate aqueous solution for 2h, then taken out, dried and treated by plasma to obtain the pretreated cotton fiber, and the plasma treatment conditions are as follows: vacuumizing the plasma instrument, then introducing oxygen, setting the power to 160W, and treating for 5min.

[0033] The preparation method of the bio-based adhesive in step S1 comprises the following steps:

[0034] 15g gelatin is soaked in cold water for swelling, then heated to 50℃ for dissolution, 10g glycyrrhizin and 37.5g 35wt% formaldehyde aqueous solution are added, ultrasonic dispersion is performed under nitrogen atmosphere, then the pH value is adjusted to 5, the temperature is raised to 65℃, and reaction is performed for 4h, then the solvent is removed by evaporation under reduced pressure, and the remaining material is spray dried to obtain a gelatin compound; 8.8g L-tryptophan is added to 200mL ionized water, 10g 38wt% acetic acid aqueous solution is added dropwise, the pH value is adjusted to 6, then 24.7g of the gelatin compound, 12.5g polyvinyl alcohol, 8.6g dialdehyde starch and 1.5g hydroxyethyl cellulose are added, heated and stirred at 70℃ for 2h, and then cooled to obtain the bio-based adhesive. Example 2

[0035] A preparation method of a low-swelling sanitary tampon comprises the following steps:

[0036] S1, carding pretreated cotton fibers, then laying the carded cotton fibers to form a single-layer cotton fiber with a grammage of 12g / m 2 , coating the single-layer cotton fiber with a bio-based adhesive, then covering the single-layer cotton fiber with another single-layer cotton fiber to obtain a double-layer cotton fiber, stacking the double-layer cotton fiber to obtain a cotton web layer, wrapping the cotton web layer with a non-woven fabric with a grammage of 30g / m 2 , and then compressing to form a strip-shaped fiber layer;

[0037] S2, fixing a cotton thread at the center of the strip-shaped fiber layer, with the tail end of the cotton thread exposed 15 cm outside the strip-shaped fiber layer, then rolling the strip-shaped fiber layer to form a long strip-shaped cylindrical absorbent, and then performing microwave heating treatment at 60℃ for 5s after compression molding in a former to obtain a cotton strip body of the sanitary tampon;

[0038] S3, compressing the tampon body of the sanitary tampon into a catheter to obtain a low-swelling sanitary tampon.

[0039] The preparation method of the pretreated cotton fiber in step S1 is as follows: the cotton fiber is immersed in a 20wt% sodium sulfate aqueous solution for 3h, then taken out, dried, and treated by plasma to obtain the pretreated cotton fiber, and the plasma treatment conditions are as follows: vacuumizing the plasma instrument, then introducing oxygen, setting the power to 160W, and treating for 5min.

[0040] The preparation method of the bio-based adhesive in step S1 comprises the following steps:

[0041] 12g gelatin is soaked in cold water for swelling, then heated to 50℃ for dissolution, 6g glycyrrhizin and 36g 40wt% formaldehyde aqueous solution are added, ultrasonic dispersion is carried out under nitrogen atmosphere, then the pH value is adjusted to 6, the temperature is raised to 55℃, and reaction is carried out for 4h, after the reaction is completed, the solvent is removed by evaporation under reduced pressure, and the remaining material is spray dried to obtain a gelatin compound; 8g L-tryptophan is added to 200mL deionized water, 10g 38wt% acetic acid aqueous solution is added dropwise, the pH value is adjusted to 5, then 20g gelatin compound, 10g polyvinyl alcohol, 5g dialdehyde starch and 1g hydroxyethyl cellulose are added, heated and stirred at 60℃ for 2.5h, and after the reaction is completed, cooling is carried out to obtain a bio-based adhesive. Example 3

[0042] A preparation method of a low-swelling sanitary tampon comprises the following steps:

[0043] S1, the pretreated cotton fiber is carded, after the carding is completed, a single layer of cotton fiber with a grammage of 16g / m 2 is laid up, a bio-based adhesive is coated on the single layer of cotton fiber, then another single layer of cotton fiber is covered to obtain a double layer of cotton fiber, the double layer of cotton fiber is stacked to obtain a cotton web layer, the cotton web layer is wrapped with a non-woven fabric with a grammage of 50g / m 2 , and then pressed into a strip-shaped fiber layer;

[0044] S2, the cotton thread is fixed at the center part of the strip-shaped fiber layer, the tail end of the cotton thread is exposed outside the strip-shaped fiber layer by 20cm, then the strip-shaped fiber layer is rolled to form an elongated cylindrical absorbent, after being pressed and formed in a former, microwave heating treatment is carried out at 65℃ for 2s to obtain a tampon body of the sanitary tampon;

[0045] S3, the tampon body of the sanitary tampon is compressed into a catheter to obtain a low-swelling sanitary tampon.

[0046] The preparation method of the pretreated cotton fiber in step S1 is as follows: the cotton fiber is immersed in a 30wt% sodium sulfate aqueous solution for 2.5h, then taken out, dried and treated by plasma. The plasma treatment conditions are as follows: the plasma instrument is vacuumed, then oxygen is introduced, the power is set to 160W, and the treatment time is 5min.

[0047] The preparation method of the bio-based adhesive in step S1 comprises the following steps:

[0048] 25g gelatin is soaked in cold water for swelling, then heated to 50℃ for dissolution, 15g glycyrrhizin and 50g 30wt% formaldehyde aqueous solution are added, ultrasonic dispersion is carried out under nitrogen atmosphere, then the pH value is adjusted to 4, the temperature is increased to 75℃, and reaction is carried out for 3h. After the reaction is completed, the solvent is removed by evaporation under reduced pressure, and the residue is spray dried to obtain a gelatin compound. 10g L-tryptophan is added to 200mL deionized water, 12g 38wt% acetic acid aqueous solution is added dropwise, the pH value is adjusted to 6, then 30g gelatin compound, 20g polyvinyl alcohol, 10g dialdehyde starch and 2g hydroxyethyl cellulose are added, heated and stirred at 70℃ for 1.5h, and the bio-based adhesive is obtained after the reaction is completed and cooled.

[0049] Comparative Example 1

[0050] A preparation method of a low-swelling sanitary tampon, similar to Example 1, differs in that the cotton fiber is not pretreated, and specifically comprises the following steps:

[0051] S1, the cotton fiber is carded, and after carding, it is laid into a single layer of cotton fiber with a grammage of 15g / m 2 The bio-based adhesive is coated on the single layer of cotton fiber, and then another single layer of cotton fiber is overlaid to obtain a double layer of cotton fiber. The double layer of cotton fiber is stacked to obtain a cotton web layer, which is wrapped with a non-woven fabric with a grammage of 40g / m 2 , and then pressed into a fibrous layer in the shape of a strip;

[0052] S2, the cotton thread is fixed at the center of the fibrous layer in the shape of a strip, with the tail end of the cotton thread exposed 15cm outside the fibrous layer in the shape of a strip. Then the fibrous layer in the shape of a strip is rolled to form a long cylindrical absorbent body, which is microwave-heated at 60℃ for 5s after being pressed and formed in a former to obtain a tampon body of a sanitary tampon;

[0053] S3, the tampon body of the sanitary tampon is compressed into a catheter to obtain a low-swelling sanitary tampon.

[0054] The preparation method of the bio-based adhesive in step S1 comprises the following steps:

[0055] 15 g gelatin was soaked in cold water for swelling, then heated to 50℃ for dissolution, 10 g glycyrrhizin and 37.5 g 35wt% formaldehyde aqueous solution were added, and after ultrasonic dispersion under nitrogen atmosphere, the pH was adjusted to 5, and the temperature was raised to 65℃ for reaction for 4 h, then the solvent was removed by vacuum evaporation, and the residue was spray dried to obtain a gelatin composite; 8.8 g L-tryptophan was added to 200 mL ionized water, 10 g 38wt% acetic acid aqueous solution was added dropwise, the pH value was adjusted to 6, then 24.7 g of the gelatin composite, 12.5 g of polyvinyl alcohol, 8.6 g of dialdehyde starch and 1.5 g of hydroxyethyl cellulose were added, and heated and stirred at 70℃ for 2 h, then cooled to obtain a bio-based adhesive.

[0056] Comparative Example 2

[0057] A method for preparing a low-swelling sanitary tampon, similar to Example 1, except that L-tryptophan is not added to the bio-based adhesive, specifically comprising the following steps:

[0058] S1, the pretreated cotton fibers were carded, and after carding, they were laid into a single layer of cotton fibers with a grammage of 15 g / m 2 The bio-based adhesive was coated on the single layer of cotton fibers, and then another single layer of cotton fibers was overlaid to obtain a double layer of cotton fibers. The cotton web layer was wrapped with a non-woven fabric with a grammage of 40 g / m 2 , and then pressed into a strip-shaped fiber layer;

[0059] S2, the cotton thread was fixed at the center of the strip-shaped fiber layer, with the tail end of the cotton thread exposed 15 cm outside the strip-shaped fiber layer, then the strip-shaped fiber layer was rolled into a long cylindrical absorbent, and after being pressed and formed in a former, it was treated by microwave heating at 60℃ for 5 s to obtain a tampon body of a sanitary tampon;

[0060] S3, the tampon body of the sanitary tampon was compressed into a catheter to obtain a low-swelling sanitary tampon.

[0061] The method for preparing the pretreated cotton fibers in step S1 is as follows: the cotton fibers were immersed in a 25wt% sodium sulfate aqueous solution for 2 h, then taken out, dried and treated with plasma to obtain the pretreated cotton fibers. The plasma treatment conditions were as follows: the plasma instrument was vacuumed, then oxygen was introduced, the power was set to 160 W, and the treatment time was 5 min.

[0062] The method for preparing the bio-based adhesive in step S1 comprises the following steps:

[0063] Dissolve 15 g of gelatin in cold water, then heat to 50℃, add 10 g of glycyrrhizin and 37.5 g of 35wt% formaldehyde solution, adjust the pH to 5 after ultrasonic dispersion under nitrogen atmosphere, and react at 65℃ for 4h. After the reaction is completed, the solvent is removed by evaporation under reduced pressure, and the residue is spray dried to obtain a gelatin composite. Then, 24.7 g of the gelatin composite, 12.5 g of polyvinyl alcohol, 8.6 g of dialdehyde starch, and 1.5 g of hydroxyethyl cellulose are heated and stirred at 70℃ for 2h to obtain a bio-based adhesive.

[0064] Comparative Example 3

[0065] A method for preparing a low-swelling sanitary tampon, similar to Example 1, except that the gelatin composite is a mixture of gelatin and glycyrrhizin, comprising the following steps:

[0066] S1, carding the pretreated cotton fibers, and after carding, laying them into a single layer of cotton fibers with a grammage of 15 g / m 2 , coating the bio-based adhesive on the single layer of cotton fibers, and then covering another single layer of cotton fibers to obtain a double layer of cotton fibers. The double layer of cotton fibers is stacked to obtain a cotton web layer, which is wrapped with a non-woven fabric with a grammage of 40 g / m 2 , and then pressed into a fibrous layer;

[0067] S2, fixing a cotton thread at the center of the fibrous layer, with the tail end of the cotton thread exposed 15 cm outside the fibrous layer, and then rolling the fibrous layer to form a long cylindrical absorbent, which is microwave heated at 60℃ for 5s after being pressed and formed in a former to obtain a tampon body of a sanitary tampon;

[0068] S3, compressing the tampon body of the sanitary tampon into a catheter to obtain a low-swelling sanitary tampon.

[0069] The method for preparing the pretreated cotton fibers in step S1 is as follows: the cotton fibers are immersed in a 25wt% sodium sulfate aqueous solution for 2h, then dried and treated with plasma to obtain the pretreated cotton fibers. The plasma treatment conditions are as follows: the plasma instrument is vacuumed, then oxygen is introduced, the power is set to 160W, and the treatment time is 5min.

[0070] The method for preparing the bio-based adhesive in step S1 comprises the following steps:

[0071] 15g gelatin was soaked in cold water for swelling, then heated to 50℃ for dissolution, 10g glycyrrhizin and 37.5g 35wt% formaldehyde aqueous solution were added, and after ultrasonic dispersion under nitrogen atmosphere, the pH was adjusted to 5, and the temperature was increased to 65℃ for reaction for 4h, then the solvent was removed by vacuum evaporation, and the residue was spray dried to obtain a gelatin composite; 8.8g L-tryptophan was added to 200mL ionized water, 10g 38wt% acetic acid aqueous solution was added dropwise, the pH value was adjusted to 6, then 24.7g gelatin composite, 12.5g polyvinyl alcohol, 8.6g dialdehyde starch and 1.5g hydroxyethyl cellulose were added, and heated and stirred at 70℃ for 2h, then cooled to obtain a bio-based adhesive after the reaction was completed.

[0072] Performance test

[0073] Randomly selected sanitary tampons prepared in Examples 1-3 and Comparative Examples 1-3, 20 each, test the expulsion force of any 10 after production, calculate the average expulsion force, the remaining 10 are placed at room temperature for 6 months, then test the average expulsion force, and test the absorption capacity, and when the absorption capacity exceeds 10g, observe whether there is liquid dripping at the tail end of the cotton thread, and the test results are as follows Table 1:

[0074] Table 1 Performance test results of sanitary tampons

[0075]

[0076] From the experimental results in Table 1, it can be seen that the sanitary tampon obtained by the present application has good storage stability, good absorption performance, and can effectively prevent menstrual blood leakage.

[0077] The bio-based adhesives obtained in Example 1 and Comparative Example 3 were uniformly coated on glass pieces, and after solidification, they were immersed in water for 2h, dried, and then 1ml of E. coli bacterial solution with a concentration of 10 5 CFU / ml was added to the surface of the glass piece sample coated with the bio-based adhesive after sterilization treatment, and cultured at 37℃ for 8h, 20μL of the cultured bacterial solution was removed and uniformly coated on the solid culture medium, and after incubation at 37℃ for 24h, the number of bacteria on the culture medium was counted, and a blank experiment was also performed. The antibacterial rate was calculated using the following formula (I):

[0078] Antibacterial rate = (A-B) / A x 100%, formula (I)

[0079] Wherein, A is the number of bacteria in the blank experiment, and B is the number of bacteria in the sample group experiment;

[0080] The test results are shown in Table 2:

[0081] Table 2 Antibacterial performance test results of bio-based adhesives

[0082] Antibacterial rate (%) Example 1 99.9 Comparative Example 3 90.3

[0083] As can be seen from the results in Table 2, the bio-based adhesive prepared by the present application has good antibacterial effect.

[0084] The above merely illustrates the preferred embodiments of the present application, and does not limit the patent scope of the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the patent protection scope of the present application.

Claims

1. A method of making a low-bulk tampon characterized in that, The method comprises the following steps: S1, pretreated cotton fibers are carded, and after carding, the single-layer cotton fibers are laid and coated with a bio-based adhesive, and then a single-layer cotton fiber is covered to obtain double-layer cotton fibers, the double-layer cotton fibers are stacked to obtain a cotton web layer, the cotton web layer is wrapped with non-woven fabric, and then pressed into a strip-shaped fiber layer; S2, a cotton thread is fixed at the center of the strip-shaped fiber layer, the tail end of the cotton thread is exposed outside the strip-shaped fiber layer by 10-20 cm, then the strip-shaped fiber layer is rolled into a long cylindrical absorbent, and after being pressed and formed in a former, microwave heating treatment is performed to obtain a tampon body of the sanitary tampon; S3, the tampon body of the sanitary tampon is compressed into a catheter to obtain a low-swelling sanitary tampon; The preparation method of the pretreated cotton fibers in step S1 is as follows: the cotton fibers are immersed in a sodium sulfate aqueous solution, taken out, dried, and then treated with plasma to obtain the pretreated cotton fibers; The concentration of the sodium sulfate aqueous solution is 20-30 wt%; The preparation method of the bio-based adhesive in step S1 comprises the following steps: The gelatin is soaked in cold water for swelling, then dissolved by heating, and then glycyrrhizin and formaldehyde aqueous solution are added, and after ultrasonic dispersion under a nitrogen atmosphere, the pH is adjusted to 4-6, and then the temperature is increased for reaction, and after the reaction is completed, the solvent is removed by vacuum evaporation, and the remaining material is spray dried to obtain a gelatin compound; L-tryptophan is added to deionized water, acetic acid aqueous solution is added dropwise, the pH value is adjusted to 5-6, and then the gelatin compound, polyvinyl alcohol, dialdehyde starch and hydroxyethyl cellulose are added, heated and stirred, and after the reaction is completed, the bio-based adhesive is obtained after cooling.

2. The method of claim 1, wherein: The basis weight of the single-layer cotton fiber in the step S1 is 12-16 g / m 2 .

3. The method of claim 1, wherein: The mass ratio of the gelatin, glycyrrhizin and formaldehyde aqueous solution is 2-5:1-3:6-10.

4. The method of claim 1, wherein: The heating and stirring temperature is 60-75℃, and the heating and stirring time is 1.5-2.5 h.

5. The method of claim 1, wherein: The basis weight of the nonwoven fabric in the step S1 is 30-50 g / m 2 .

6. The method of claim 1, wherein: The microwave heating temperature in step S2 is 50-65℃, and the microwave heating time is 2-8 s.

7. A low-bulk tampon characterized by: Prepared by the preparation method of any one of claims 1-6.

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