Production process of degradable soft cotton sanitary napkin

Abstract

The invention discloses a production process of a degradable soft cotton sanitary napkin, and belongs to the technical field of sanitary napkins, and the production process comprises the following steps: S1, preparing a degradation promoting solution containing bacillus subtilis spores, atomizing the degradation promoting solution, spraying the atomized degradation promoting solution into a cross-linking solution, and filtering to obtain degradation promoting particles; s2, preparing a degradation-promoting adhesive containing degradation-promoting particles and sodium bicarbonate powder; s3, the anti-leakage bottom film, the soft cotton core body and the soft cotton surface layer are sequentially bonded through a degradation promoting adhesive to form a semi-finished sanitary towel product; s4, the semi-finished sanitary towel is heated and dried, and sodium bicarbonate is decomposed after being heated, so that a plurality of air holes are formed in the surface of the degradation-promoting adhesive; s5, the edge of the semi-finished sanitary towel is subjected to hot-pressing bonding and then cut, and the soft cotton sanitary towel is obtained; according to the method, degradation of materials in the soft cotton sanitary napkin is accelerated through the bacillus subtilis flora, so that the degradation efficiency of the soft cotton sanitary napkin is improved, and the increasingly severe plastic pollution problem can be solved.

Description

Technical Field

[0001] This invention relates to the field of sanitary napkin technology, and specifically to a production process for a biodegradable cotton soft sanitary napkin. Background Technology

[0002] Sanitary napkins are an essential part of women's daily lives. However, many common sanitary products use a large amount of non-biodegradable raw materials. These plastic materials have extremely long degradation cycles, easily encroaching on the natural environment such as land and water, threatening the survival of humans and wild animals, and posing a potential health threat to life on Earth. Although some raw materials for sanitary napkins are biodegradable, and intermediate products such as non-woven fabrics and breathable films are made from biodegradable plastics, the degradation process of the biodegradable plastics in sanitary napkins after disposal is highly dependent on environmental factors such as temperature, humidity, and microorganisms. As a result, the degradation rate of plastics in sanitary napkins is not ideal, making it difficult to effectively alleviate the increasingly serious problem of plastic pollution.

[0003] Based on the above, Chinese Patent No. CN105671793A discloses a method for preparing polylactic acid biodegradable nonwoven fabric for the surface coating layer of sanitary products. The preparation method includes: selecting polylactic acid raw materials, drying polylactic acid chips, extruding them in a screw extruder, melt filtration, spinning polylactic acid filaments, airflow stretching, web laying, hydroentangling reinforcement, drying and winding. By combining polylactic acid filament web forming technology and hydroentangling reinforcement technology, a polylactic acid nonwoven fabric layer with high strength, soft hand feel, fluffy texture, and good permeability is obtained. It has the characteristics of being renewable, biodegradable, biocompatible, and having low carbon emissions and low energy consumption. Hydroentangling reinforcement is achieved through self-adhesion without the addition of any chemical adhesives, thus having minimal adverse environmental impact. The product has the same soft hand feel as traditional textiles and does not pill, which can overcome the defect of spunbond nonwoven fabric having a relatively hard hand feel. It can be used for the surface layer of disposable sanitary products.

[0004] The aforementioned patent discloses a nonwoven fabric that can be used as the surface layer of sanitary products such as sanitary napkins. This nonwoven fabric can achieve complete biodegradability based on the properties of polylactic acid. However, the biodegradation of polylactic acid is highly dependent on suitable environmental conditions such as temperature, humidity, and microorganisms. Otherwise, the degradation rate will be relatively low. In practice, it is difficult to create suitable environmental conditions to improve the degradation rate after sanitary products are discarded. Neither sanitary products nor the nonwoven fabric itself have the properties to improve the degradation rate. Therefore, there is still room for improvement in this nonwoven fabric. Summary of the Invention

[0005] To address the technical deficiencies in the background technology, this invention proposes a production process for biodegradable cotton-soft sanitary napkins, which solves the aforementioned technical problems and meets practical needs. The specific technical solution is as follows: A manufacturing process for biodegradable cotton soft sanitary napkins includes the following steps: S1. Disperse Bacillus subtilis spores in a coating solution and stir evenly to obtain a degradation-promoting solution. Atomize the degradation-promoting solution and spray it into a cross-linking solution to react and form a number of degradation-promoting microparticles. After filtering the solution, the degradation-promoting microparticles are dried. Among them, the degradation-promoting solution reacts with the cross-linking solution to form a tiny particulate encapsulation material that encapsulates Bacillus subtilis spores. The encapsulation material and Bacillus subtilis spores together form degradation-promoting microparticles. S2. Mix and stir the bio-based adhesive with the bio-based microparticles and sodium bicarbonate powder to obtain the bio-based adhesive. S3. The leak-proof bottom film, the soft cotton core, and the soft cotton surface layer are stacked and bonded together along the thickness direction to form a semi-finished sanitary napkin. The leak-proof bottom film and the soft cotton core, as well as the soft cotton core and the soft cotton surface layer, are bonded together with a biodegradable adhesive. S4. The semi-finished sanitary napkin is conveyed to the drying equipment for heating and drying. Sodium bicarbonate decomposes when heated and forms several pores on the surface of the degradable adhesive. After the degradable adhesive is cured, it forms a degradable adhesive layer with several pores. S5. The edges of the semi-finished sanitary napkin are bonded and fixed to the soft surface layer and the leak-proof bottom film by hot pressing and then cut. The soft surface layer and the leak-proof bottom film wrap the soft core and together form a soft sanitary napkin.

[0006] As a further technical solution of the present invention, the encapsulation solution is selected as a sodium alginate solution with a concentration of 2% to 4%, and the crosslinking solution is selected as a calcium chloride solution with a concentration of 2% to 4%.

[0007] As a further technical solution of the present invention, the encapsulation solution also contains glycerol, surfactant, and soluble starch. The encapsulation solution comprises the following components by mass percentage: sodium alginate 2%~4%, glycerol 5%~10%, soluble starch 0.5%~2%, surfactant 0.2%~0.5%, and the balance being sterile water.

[0008] As a further technical solution of the present invention, the degradation-promoting solution comprises the following components by mass percentage: 5%~20% Bacillus subtilis spores and 80%~95% encapsulation solution.

[0009] As a further technical solution of the present invention, the degradation-promoting adhesive comprises the following components by mass percentage: 2%~10% degradation-promoting microparticles, 0.5%~1% sodium bicarbonate powder, and 89%~97.5% bio-based adhesive.

[0010] As a further technical solution of the present invention, the leak-proof bottom film is selected from one of polyhydroxyalkanoate film, polyhydroxybutyrate film, polylactic acid film, and polybutylene succinate film.

[0011] As a further technical solution of the present invention, the cotton core is composed of several layers of cotton fiber webs stacked along the thickness direction.

[0012] As a further technical solution of the present invention, the cotton soft surface layer is made of one of the following: spunlace nonwoven fabric made of all-cotton fibers, needle-punched nonwoven fabric made of all-cotton fibers, or wet-laid nonwoven fabric made of all-cotton fibers.

[0013] The beneficial effects of this invention are as follows: This invention discloses a highly efficient degradable cotton-soft sanitary napkin and its manufacturing process. The cotton-soft sanitary napkin is composed of a leak-proof bottom film, a cotton-soft core, and a cotton-soft surface layer, which are sequentially bonded together by a degradable adhesive that promotes material degradation. During the manufacturing process of the degradable adhesive, degradable microparticles containing Bacillus subtilis spores are introduced. Furthermore, during the curing process of the degradable adhesive, the decomposition of sodium bicarbonate creates several pores on the surface of the degradable adhesive layer. During use or after disposal, menstrual blood or other liquids can penetrate through these pores and come into contact with the degradable microparticles, causing the Bacillus subtilis spores to germinate rapidly and grow into a Bacillus subtilis flora. This Bacillus subtilis flora accelerates the degradation of materials in the cotton-soft sanitary napkin, thereby improving its degradation efficiency and helping to solve the increasingly serious problem of plastic pollution. Detailed Implementation

[0014] The embodiments of the present invention will be described below with reference to relevant examples. The embodiments of the present invention are not limited to the following examples, and the present invention relates to relevant necessary components in this technical field, which should be regarded as well-known technology in this technical field and can be known and mastered by those skilled in this technical field.

[0015] A manufacturing process for biodegradable cotton soft sanitary napkins includes the following steps: S1. Disperse Bacillus subtilis spores in a coating solution and stir evenly to obtain a degradation-promoting solution. Atomize the degradation-promoting solution and spray it into a cross-linking solution to react and form a number of degradation-promoting microparticles. After filtering the solution, the degradation-promoting microparticles are dried. Among them, the degradation-promoting solution reacts with the cross-linking solution to form a tiny particulate encapsulation material that encapsulates Bacillus subtilis spores. The encapsulation material and Bacillus subtilis spores together form degradation-promoting microparticles. S2. Mix and stir the bio-based adhesive with the bio-based microparticles and sodium bicarbonate powder to obtain the bio-based adhesive. S3. The leak-proof bottom film, the soft cotton core, and the soft cotton surface layer are stacked and bonded together along the thickness direction to form a semi-finished sanitary napkin. The leak-proof bottom film and the soft cotton core, as well as the soft cotton core and the soft cotton surface layer, are bonded together with a biodegradable adhesive. S4. The semi-finished sanitary napkin is conveyed to the drying equipment for heating and drying. Sodium bicarbonate decomposes when heated and forms several pores on the surface of the degradable adhesive. After the degradable adhesive is cured, it forms a degradable adhesive layer with several pores. S5. The edges of the semi-finished sanitary napkin are bonded and fixed to the soft surface layer and the leak-proof bottom film by hot pressing and then cut. The soft surface layer and the leak-proof bottom film wrap the soft core and together form a soft sanitary napkin.

[0016] This invention discloses a highly biodegradable cotton-soft sanitary napkin, which mainly consists of a leak-proof bottom film, a cotton-soft core, and a cotton-soft surface layer. The leak-proof bottom film uses one of the following as raw materials: biodegradable polyhydroxyalkanoate, polyhydroxybutyrate, polylactic acid, and polybutylene succinate. The leak-proof bottom film is made of biodegradable materials and produced using common film production processes. During the film production process, fillers such as calcium carbonate can be added to the raw materials. After the film is formed, the surface of the film will form several breathable and waterproof microporous structures after stretching, making the leak-proof bottom film a waterproof and breathable membrane. The leak-proof bottom film in this invention is used to replace the currently common waterproof and breathable polyethylene film, ensuring that the cotton-soft sanitary napkin has good breathability and leak-proof performance. Furthermore, the biodegradability of the leak-proof bottom film is a necessary condition for the complete degradation of the cotton-soft sanitary napkin. Furthermore, the cotton core, as the main structure in cotton-soft sanitary napkins for absorbing menstrual blood, consists of several layers of cotton fiber webs stacked along the thickness direction. During the manufacturing process, cotton fibers are combed and laid out using methods such as airflow to form a web. Then, multiple layers of cotton fiber webs are sequentially stacked along the thickness direction and compressed under appropriate pressure. The resulting multiple layers of cotton fiber webs together form the cotton core. Because the cotton core needs to absorb and retain a certain amount of menstrual blood, its thickness is relatively high. If the cotton fibers pass through… The cotton fiber core is formed by direct airflow web laying. However, the cotton fibers in the core are easily unevenly distributed. When the core absorbs menstrual blood, it tends to clump, resulting in an uneven interior and affecting the comfort of the sanitary napkin. On the other hand, because the cotton fiber web is thinner, the cotton fibers can be more evenly distributed during the web laying process. This allows the cotton fibers in the multi-layered cotton fiber web core to also be evenly distributed. When the core absorbs menstrual blood, it is less likely to clump, thus improving the comfort of the sanitary napkin. Furthermore, the cotton-soft surface layer is a nonwoven fabric composed entirely of cotton fibers. It can be made from one of the following: spunlace nonwoven fabric, needle-punched nonwoven fabric, or wet-laid nonwoven fabric. The cotton fibers are processed using common spunlace, needle-punching, or wet-laid nonwoven fabric processes to create the nonwoven fabric, which then serves as the cotton-soft surface layer of this invention. The surface of the cotton-soft surface layer is soft and smooth, improving user comfort during use. The upper surface of the cotton-soft surface layer can be embossed using common embossing processes to create various embossing patterns. Different embossing shapes enhance the absorbency and leak-proof performance of the cotton-soft surface layer. Additionally, both the cotton-soft core and the cotton-soft surface layer are made of cotton fibers, while the leak-proof bottom film is made of biodegradable materials, enabling the cotton-soft sanitary napkin to be completely degradable. After use and disposal, the cotton-soft sanitary napkin can degrade into small molecular components within a certain time, which helps solve the increasingly serious problem of plastic pollution.

[0017] This invention also discloses a production process for highly efficient degradable soft sanitary napkins. The soft sanitary napkins produced using this process, after use and disposal, can shorten the time it takes for them to completely degrade in the natural environment. This invention mainly relies on degradative microparticles to shorten the degradation time of the soft sanitary napkins. In step S1, the encapsulation solution is a 2%~4% sodium alginate solution, and the degradative solution includes the following components by mass percentage: 5%~20% Bacillus subtilis spores, 80%~95% encapsulation solution, and the crosslinking solution is a 2%~4% calcium chloride solution. After the degradation-promoting solution is atomized, it forms droplets composed of sodium alginate solution and Bacillus subtilis spores. When the droplets come into contact with the cross-linking solution, sodium alginate undergoes ion exchange with sodium ions in the solution and calcium ions in calcium chloride to form calcium alginate gel. This causes the droplets to change from a liquid state to gel-like small particles. The calcium alginate gel is filled with Bacillus subtilis spores, and the filling material is calcium alginate. After filtering the solution after the reaction, small particles composed of Bacillus subtilis spores filled with calcium alginate gel are obtained. After drying the small particles to remove internal moisture, the degradation-promoting microparticles are obtained. In step S2 of this invention, degradable microparticles, sodium bicarbonate powder, and bio-based adhesive are mixed to obtain a degradable adhesive mainly used for bonding and fixing the internal materials of cotton soft sanitary napkins. During the preparation of the degradable adhesive, a suitable dispersant can be added to improve the uniformity of dispersion of the degradable microparticles and sodium bicarbonate powder. In step S3, after the leak-proof bottom film and the cotton soft core, as well as the cotton soft core and the cotton soft surface layer are bonded and fixed by the degradable adhesive, the inside of the cotton soft sanitary napkin contains an appropriate amount of degradable adhesive. When the cotton soft sanitary napkin is used and discarded, the moist environment will activate Bacillus subtilis spores to germinate and gradually grow into Bacillus subtilis. Bacillus subtilis can form a biofilm on the material surface of the leak-proof bottom film, the cotton soft core, and the cotton soft surface layer, creating a microenvironment for other cellulose-degrading bacteria. Through the synergistic effect between microbial communities, the material degradation process is accelerated, thereby increasing the degradation speed of the cotton soft sanitary napkin. It should be noted that, because the degradable microparticles undergo drying treatment, and preferably a low-temperature drying process, the Bacillus subtilis spores remain dormant but still active inside the microparticles. During use, the cotton sanitary napkin absorbs menstrual blood, vaginal secretions, and other substances, which contain nutrients required for the growth of Bacillus subtilis. Furthermore, the environment in which the cotton sanitary napkin is discarded may become humid due to rain or other factors. This environment is conducive to the germination and growth of Bacillus subtilis spores, allowing the cotton sanitary napkin to be rapidly degraded by the Bacillus subtilis formed from the germination of the Bacillus subtilis spores inside after disposal. In step S4 of this invention, the biodegradable adhesive remains liquid after coating. The semi-finished sanitary napkin is dried in a drying device at 60-80°C. This temperature promotes the decomposition of sodium bicarbonate in the biodegradable adhesive to form carbon dioxide. As the carbon dioxide escapes from the biodegradable adhesive, it forms several pores on the surface of the adhesive. These pores improve the efficiency of complete drying of the biodegradable adhesive and biodegradable particles. Furthermore, Bacillus subtilis spores can maintain their activity for a long time in an environment of 60-80°C. After drying and curing, the biodegradable adhesive forms a structure with several... The dry-pore biodegradable adhesive layer allows menstrual blood, rainwater, and other liquids to penetrate the layer and come into contact with the biodegradable microparticles during use and after disposal. These liquids then come into contact with Bacillus subtilis spores, which promotes rapid germination and formation of Bacillus subtilis. This avoids the situation where the biodegradable microparticles remain in a dry environment due to the good sealing of the adhesive layer. After disposal, the biodegradable sanitary napkin can efficiently form a Bacillus subtilis microbial community inside, allowing it to quickly enter the degradation stage. In step S5 of the present invention, after the leak-proof bottom film, the soft core, and the soft surface layer are sequentially stacked and bonded along the thickness direction, hot pressing along the edge of the sanitary napkin semi-finished product can melt the leak-proof bottom film and bond it with the soft surface layer. That is, the soft core is wrapped inside by the leak-proof bottom film and the soft surface layer. Finally, the sanitary napkin semi-finished product is cut into the shape of a common sanitary napkin along the hot-pressed bonding position, thereby obtaining the soft sanitary napkin of the present invention.

[0018] Furthermore, the encapsulation solution also contains glycerol, surfactant, and soluble starch. The encapsulation solution comprises the following components by mass percentage: sodium alginate 2%–4%, glycerol 5%–10%, soluble starch 0.5%–2%, surfactant 0.2%–0.5%, and the balance being sterile water. Glycerol can mitigate the osmotic impact during the reaction of sodium alginate and calcium chloride, preventing damage to Bacillus subtilis spores and helping to maintain higher activity of Bacillus subtilis spores. Soluble starch can serve as a slow-release nutrient component for Bacillus subtilis spores during the germination stage, providing nutrients for the germination and growth of Bacillus subtilis spores. The surfactant is selected from polyoxyethylene alkylphenol ether and polyoxyethylene fatty alcohol ether, and the surfactant can improve the dispersibility of Bacillus subtilis spores in the encapsulation solution.

[0019] Furthermore, the biodegradable adhesive comprises the following components by mass percentage: 2%~10% biodegradable microparticles, 0.5%~1% sodium bicarbonate powder, and 89%~97.5% bio-based adhesive. As the main component of the biodegradable adhesive, the bio-based adhesive is mainly derived from renewable biomass resources such as plants, animals, and microorganisms, and has better environmental compatibility, making the biodegradable adhesive biodegradable, thereby enabling the cotton-soft sanitary napkin to be completely degradable.

[0020] In summary, this invention discloses a highly efficient degradable soft sanitary napkin and its manufacturing process. The soft sanitary napkin is composed of a leak-proof bottom film, a soft core, and a soft surface layer, which are sequentially bonded together by a degradable adhesive that promotes material degradation. During the manufacturing process of the degradable adhesive, degradable microparticles containing Bacillus subtilis spores are introduced. Furthermore, during the curing process of the degradable adhesive, the decomposition of sodium bicarbonate creates several pores on the surface of the degradable adhesive layer. During use or after disposal, menstrual blood or other liquids can penetrate through these pores and come into contact with the degradable microparticles, causing the Bacillus subtilis spores to germinate rapidly and grow into a Bacillus subtilis flora. This Bacillus subtilis flora accelerates the degradation of materials in the soft sanitary napkin, thereby improving its degradation efficiency and contributing to solving the increasingly serious problem of plastic pollution.

[0021] The present invention will be further illustrated below through examples and comparative examples.

[0022] Example 1 S1. Disperse Bacillus subtilis spores in a coating solution and stir evenly to obtain a degradation-promoting solution. Atomize the degradation-promoting solution and spray it into a 3% calcium chloride solution to react and form a number of degradation-promoting particles. After filtering the solution, the degradation-promoting particles obtained are dried. The encapsulation solution comprises the following components by mass percentage: sodium alginate 3%, glycerol 5%, soluble starch 0.5%, polyoxyethylene alkylphenol ether 0.2%, and the balance being sterile water; The degradation-promoting solution comprises the following components by mass percentage: 5% Bacillus subtilis spores and 95% encapsulation solution; S2. Mix and stir the bio-based adhesive with the bio-based microparticles and sodium bicarbonate powder to obtain the bio-based adhesive. The biodegradable adhesive comprises the following components by weight percentage: 2% biodegradable microparticles, 0.5% sodium bicarbonate powder, and 97.5% bio-based adhesive; S3. Polylactic acid waterproof and breathable membrane, multi-layer cotton fiber core, and all-cotton fiber spunlace nonwoven fabric are layered sequentially along the thickness direction and bonded together with a biodegradable adhesive to form a semi-finished sanitary napkin. The dry coating amount of the degradable adhesive between the polylactic acid waterproof and breathable membrane and the multilayer cotton fiber core, as well as between the multilayer cotton fiber core and the all-cotton fiber spunlace nonwoven fabric, is 15 gsm. S4. The semi-finished sanitary napkin is conveyed to the drying equipment and heated to 70°C for drying. Sodium bicarbonate decomposes when heated and forms several pores on the surface of the degradable adhesive. After the degradable adhesive is cured, it forms a degradable adhesive layer with several pores. S5. The edges of the semi-finished sanitary napkin are bonded and fixed to each other by hot pressing with spunlace nonwoven fabric of pure cotton fiber and polylactic acid waterproof and breathable membrane, and then cut. The spunlace nonwoven fabric of pure cotton fiber and polylactic acid waterproof and breathable membrane wrap the multi-layer cotton fiber core and together form a soft sanitary napkin.

[0023] Example 2 The difference between this embodiment and Embodiment 1 above is that, in step S1, the encapsulation solution includes the following components by mass percentage: sodium alginate 3%, glycerol 6.5%, soluble starch 1%, polyoxyethylene alkylphenol ether 0.3%, and the balance being sterile water; the degradation-promoting solution includes the following components by mass percentage: Bacillus subtilis spores 10%, encapsulation solution 90%; the operation and raw material ratio of the remaining steps are based on Embodiment 1 above.

[0024] Example 3 The difference between this embodiment and Embodiment 1 above is that, in step S1, the encapsulation solution includes the following components by mass percentage: sodium alginate 3%, glycerol 8%, soluble starch 1.5%, polyoxyethylene alkylphenol ether 0.4%, and the balance being sterile water; the degradation-promoting solution includes the following components by mass percentage: Bacillus subtilis spores 15%, encapsulation solution 85%; the operation and raw material ratio of the remaining steps are based on Embodiment 1 above.

[0025] Example 4 The difference between this embodiment and Embodiment 1 above is that, in step S1, the encapsulation solution includes the following components by mass percentage: sodium alginate 3%, glycerol 10%, soluble starch 2%, polyoxyethylene alkylphenol ether 0.5%, and the balance being sterile water; the degradation-promoting solution includes the following components by mass percentage: Bacillus subtilis spores 20%, encapsulation solution 80%; the operation and raw material ratio of the remaining steps are based on Embodiment 1 above.

[0026] Example 5 The difference between this embodiment and Embodiment 1 above is that, in step S2, the degradable adhesive includes the following components by mass percentage: 6% degradable microparticles, 0.75% sodium bicarbonate powder, and 93.25% bio-based adhesive; the operation and raw material ratio of the remaining steps are based on Embodiment 1 above.

[0027] Example 6 The difference between this embodiment and Embodiment 1 above is that, in step S2, the degradation-promoting adhesive includes the following components by mass percentage: 10% degradation-promoting microparticles, 1% sodium bicarbonate powder, and 89% bio-based adhesive; the operation and raw material ratio of the remaining steps are based on Embodiment 1 above.

[0028] Comparative Example 1 S1. Polylactic acid waterproof and breathable membrane, multi-layer cotton fiber core, and all-cotton fiber spunlace nonwoven fabric are layered sequentially along the thickness direction and bonded together with bio-based adhesive to form a semi-finished sanitary napkin. The dry coating amount of the bio-based adhesive between the polylactic acid waterproof and breathable membrane and the multi-layer cotton fiber core, as well as between the multi-layer cotton fiber core and the all-cotton fiber spunlace nonwoven fabric, is 15 gsm. S2. The semi-finished sanitary napkin is conveyed to the drying equipment and heated to 70°C for drying. After the bio-based adhesive is cured, a bio-based adhesive layer is formed. S3. The edges of the semi-finished sanitary napkin are bonded and fixed to each other by hot pressing with spunlace nonwoven fabric of pure cotton fiber and polylactic acid waterproof and breathable membrane, and then cut. The spunlace nonwoven fabric of pure cotton fiber and polylactic acid waterproof and breathable membrane wrap multiple layers of cotton fiber core and together form a soft sanitary napkin.

[0029] The degradation ability of the cotton-soft sanitary napkins obtained in all the above embodiments and comparative examples was tested: several pads of each type of cotton-soft sanitary napkin were taken for testing. After absorbing 50mL of simulated menstrual blood, the cotton-soft sanitary napkins were placed in the same environment. Different cotton-soft sanitary napkins needed to be isolated from each other. Each type of cotton-soft sanitary napkin was divided into 6 groups. The weight loss rate of the cotton-soft sanitary napkins in test group 1 was measured 30 days after the start of the test, the weight loss rate of the cotton-soft sanitary napkins in test group 2 was measured 60 days after the start of the test, and the weight loss rate of the cotton-soft sanitary napkins in test group 3 was measured 90 days after the start of the test. Weight loss rate testing was conducted on the cotton soft sanitary napkins in test group 4 120 days after the start of the test, the cotton soft sanitary napkins in test group 5 180 days after the start of the test, and the cotton soft sanitary napkins in test group 6 270 days after the start of the test. The specific procedure for weight loss rate testing was as follows: the cotton soft sanitary napkins that had completed the test were dried and weighed. The weight was compared with the weight of the cotton soft sanitary napkins before the test, and the ratio of the weight loss of the cotton soft sanitary napkins after the test to the weight before the test was calculated, thereby calculating the weight loss rate of the cotton soft sanitary napkins. The test results of the degradation ability of cotton soft sanitary napkins are shown in Table 1 below:

[0030] Table 1 The data in Table 1 above are explained below. Comparative Example 1 is used as a blank control group. The higher the weight loss rate, the more weight the cotton soft sanitary napkin loses after the test, which indicates that its degradation speed is faster. As can be seen from the data in Table 1 above, comparing Examples 1-4, it can be seen that the degradation speed of cotton soft sanitary napkins increases with the increase of Bacillus subtilis spores. This is because after the concentration of Bacillus subtilis spores in the degradation solution increases, the degradation particles formed after the degradation solution reacts with the calcium chloride solution contain more Bacillus subtilis spores. During the degradation process, cotton soft sanitary napkins can form a larger Bacillus subtilis colony in the same amount of time, thus having a higher degradation speed. Comparing Examples 1, 5, and 6, it can be seen that the degradation rate of the cotton-soft sanitary napkin increases with the increase of the amount of degradation-promoting particles added. Furthermore, because the increased amount of degradation-promoting particles requires the addition of more sodium bicarbonate and the formation of more pores, the degradation-promoting particles can fully contact moisture and nutrients through these pores. During the degradation process, the cotton-soft sanitary napkin can form a larger Bacillus subtilis colony within the same time frame, resulting in a higher degradation rate. Comparing Examples 4 and 5, although the degradation-promoting adhesive in Example 4 contains more Bacillus subtilis spores, the addition of more sodium bicarbonate in the degradation-promoting adhesive in Example 5 allows for the formation of more pores on the surface of the degradation-promoting adhesive layer during the drying process. This results in a higher reproduction rate of Bacillus subtilis spores during germination and early growth, thus giving the cotton-soft sanitary napkin a higher degradation rate.

[0031] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A manufacturing process for biodegradable cotton soft sanitary napkins, characterized in that, Includes the following steps: S1. Disperse Bacillus subtilis spores in a coating solution and stir evenly to obtain a degradation-promoting solution. Atomize the degradation-promoting solution and spray it into a cross-linking solution to react and form a number of degradation-promoting microparticles. After filtering the solution, the degradation-promoting microparticles are dried. Among them, the degradation-promoting solution reacts with the cross-linking solution to form a tiny particulate encapsulation material that encapsulates Bacillus subtilis spores. The encapsulation material and Bacillus subtilis spores together form degradation-promoting microparticles. S2. Mix and stir the bio-based adhesive with the bio-based microparticles and sodium bicarbonate powder to obtain the bio-based adhesive. S3. The leak-proof bottom film, the soft cotton core, and the soft cotton surface layer are stacked and bonded together along the thickness direction to form a semi-finished sanitary napkin. The leak-proof bottom film and the soft cotton core, as well as the soft cotton core and the soft cotton surface layer, are bonded together with a biodegradable adhesive. S4. The semi-finished sanitary napkin is conveyed to the drying equipment for heating and drying. Sodium bicarbonate decomposes when heated and forms several pores on the surface of the degradable adhesive. After the degradable adhesive is cured, it forms a degradable adhesive layer with several pores. S5. The edges of the semi-finished sanitary napkin are bonded and fixed to the soft surface layer and the leak-proof bottom film by hot pressing and then cut. The soft surface layer and the leak-proof bottom film wrap the soft core and together form a soft sanitary napkin.

2. The production process of the biodegradable cotton soft sanitary napkin according to claim 1, characterized in that, The encapsulation solution is a sodium alginate solution with a concentration of 2% to 4%, and the cross-linking solution is a calcium chloride solution with a concentration of 2% to 4%.

3. The production process of the biodegradable cotton soft sanitary napkin according to claim 2, characterized in that, The encapsulation solution also contains glycerol, surfactant, and soluble starch. The encapsulation solution comprises the following components by mass percentage: sodium alginate 2%~4%, glycerol 5%~10%, soluble starch 0.5%~2%, surfactant 0.2%~0.5%, and the balance being sterile water.

4. The production process of the biodegradable cotton soft sanitary napkin according to claim 1, characterized in that, The degradation-promoting solution comprises the following components by mass percentage: 5%–20% Bacillus subtilis spores and 80%–95% encapsulation solution.

5. The production process of the biodegradable cotton soft sanitary napkin according to claim 1, characterized in that, The biodegradable adhesive comprises the following components by weight percentage: 2%~10% biodegradable microparticles, 0.5%~1% sodium bicarbonate powder, and 89%~97.5% bio-based adhesive.

6. The production process of the biodegradable cotton soft sanitary napkin according to claim 1, characterized in that, The leak-proof bottom film is selected from one of the following: polyhydroxyalkanoate film, polyhydroxybutyrate film, polylactic acid film, and polybutylene succinate film.

7. The production process of the biodegradable cotton soft sanitary napkin according to claim 1, characterized in that, The cotton core is composed of several layers of cotton fiber webs stacked along the thickness direction.

8. The production process of the biodegradable cotton soft sanitary napkin according to claim 1, characterized in that, The soft cotton surface layer is made of one of the following: spunlace nonwoven fabric made of all-cotton fibers, needle-punched nonwoven fabric made of all-cotton fibers, or wet-laid nonwoven fabric made of all-cotton fibers.

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