An absorbent core with SAP film structure and preparation method thereof

Abstract

The present invention relates to an absorption core of a SAP membrane structure and a preparation method thereof, wherein the absorption core of the SAP membrane structure includes, from top to bottom, an upper non-woven fabric layer, an absorption layer and a lower non-woven fabric layer; the raw material of the absorption layer includes the following components by mass fraction: 20-50 parts of modified polylactic acid, 10-20 parts of SAP resin, 10-20 parts of cellulose-chitosan composite, 0.5-5 parts of auxiliary agent, and 10-50 parts of solvent; wherein the modified polylactic acid is obtained by reacting acrylic anhydride-modified gelatin with acrylic acid-grafted polylactic acid. The absorption core of the present invention not only has excellent water absorption capacity and can efficiently absorb and store liquid, but also has the characteristics of good biocompatibility and easy degradation, can meet the performance requirements of products such as sanitary napkins and diapers, overcomes the shortcomings existing in the prior art, and has broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of sanitary products, in particular to an absorbent core with a SAP film structure and a preparation method thereof. Background Art

[0002] Sanitary napkins and diapers are essential hygiene products in modern life, providing a vital guarantee for the comfort of women, children, and other groups. The absorbent core is the core component of sanitary napkins and diapers, and the product's liquid absorption rate and liquid storage performance are both determined by the absorbent core's performance.

[0003] Absorbent cores typically consist of absorbent resins such as polyacrylic acid and polyacrylate resins, and covering materials such as non-woven fabrics, tissues, or organic fibers. While current absorbent cores have improved liquid absorption, they still suffer from limitations in absorption rate and liquid storage capacity, failing to balance multiple performance requirements. Furthermore, acrylic resins are difficult to biodegrade, making recycling absorbent cores difficult and costly, placing significant pressure on environmental protection and failing to meet current societal trends toward environmentally friendly and green development.

[0004] In summary, there is an urgent need to develop a new technical solution to solve the problems existing in the existing technology and meet the needs of the market and consumers. Summary of the Invention

[0005] Based on this, the present invention provides an absorbent core with a SAP membrane structure and a method for preparing the same. The absorbent core with a SAP membrane structure provided by the present invention comprises an absorbent layer composed of components such as a modified polylactic acid resin, an SAP resin, and a cellulose-chitosan composite. The absorbent core not only has excellent water absorption capacity, enabling efficient absorption and storage of liquids, but also exhibits good biocompatibility and easy degradation. This core can meet the performance requirements of products such as sanitary napkins and diapers, overcomes the shortcomings of existing technologies, and has broad application prospects.

[0006] One object of the present invention is to provide an absorbent core of a SAP film structure, wherein the absorbent core of the SAP film structure comprises, from top to bottom, an upper non-woven fabric layer, an absorbent layer, and a lower non-woven fabric layer;

[0007] The raw materials of the absorption layer include the following components in parts by mass:

[0008]

[0009] in,

[0010] The modified polylactic acid is obtained by reacting acrylic anhydride-modified gelatin with acrylic acid-grafted polylactic acid.

[0011] SAP resin (Super Absorbent Polymer) is a polymer material with extremely strong water absorption and water retention properties. This type of resin can absorb hundreds or even thousands of times its own weight in water, and therefore has been widely used in absorbent products such as sanitary napkins.

[0012] Furthermore, the preparation method of the modified polylactic acid comprises the following steps:

[0013] S1, mixing hydroxy-terminated polylactic acid, acrylic acid, a catalyst and a polymerization inhibitor, and heating the mixture to react to obtain acrylic acid-grafted polylactic acid;

[0014] S2, mixing gelatin and acrylic anhydride, and reacting at low temperature to obtain acrylic anhydride-modified gelatin;

[0015] S3, mixing the acrylic acid grafted polylactic acid, acrylic anhydride modified gelatin, a crosslinking agent and an initiator, and heating the mixture under the protection of an inert gas to react, thereby obtaining modified polylactic acid.

[0016] Furthermore, in step S1, the temperature of the heating reaction is 80-120°C; in step S2, the temperature of the low-temperature reaction is 0-5°C; and in step S3, the temperature of the heating reaction is 60-90°C.

[0017] Furthermore, in step S1, the mass ratio of the hydroxy-terminated polylactic acid to acrylic acid is 1:(0.1-0.5).

[0018] Furthermore, in step S2, the mass ratio of gelatin to acrylic anhydride is 1:(0.5-2).

[0019] Furthermore, in step S3, the mass ratio of the acrylic acid grafted polylactic acid to the acrylic anhydride modified gelatin is 1:(0.1-2).

[0020] Furthermore, the cellulose-chitosan composite is a mixture of oxidized cellulose and carboxymethyl chitosan.

[0021] Furthermore, the mass ratio of the oxidized cellulose to carboxymethyl chitosan is 1:(2-5).

[0022] Another object of the present invention is to provide a method for preparing the absorbent core of the SAP film structure, comprising the following steps:

[0023] Modified polylactic acid, SAP resin, cellulose-chitosan composite and additives are laid on the surface of the lower non-woven fabric layer, and a solvent is sprayed to obtain an absorption layer. Then, an upper non-woven fabric layer is laid on the surface of the absorption layer, and after drying, an absorption core with a SAP membrane structure is obtained.

[0024] The present invention has the following beneficial effects:

[0025] The absorbent core of the SAP membrane structure provided by the present invention is obtained by compounding modified polylactic acid resin, SAP resin, cellulose-chitosan complex and other components to obtain an absorption layer. Polylactic acid is a biodegradable polymer material with good mechanical properties and easy processing. However, its hydrophilicity is poor, and its application in water-absorbing materials will cause a decrease in liquid absorption performance. The present invention further polymerizes polylactic acid and gelatin after grafting acrylate groups, thereby introducing gelatin molecules into the polylactic acid structure, greatly improving the hydrophilicity of polylactic acid, facilitating the flow and transfer of liquid in the polymer network, thereby improving the absorption rate and liquid storage capacity of water and blood. The modified polylactic acid also has good compatibility with SAP resin. After compounding with cellulose-chitosan complex, multiple components can synergize and enhance the performance, further improving the water absorption and liquid storage performance. In addition, the polylactic acid resin modified with gelatin has a certain bonding ability, and can also produce synergistic effects with the polar groups of the cellulose-chitosan complex through hydrogen bonds and intermolecular forces, thereby tightly combining with the upper and lower covering layers, avoiding the use of chemical adhesives. In summary, the absorbent core of the SAP membrane structure of the present invention has excellent mechanical properties, water absorption properties and liquid storage properties, and at the same time has strong bioaffinity and is degradable, which overcomes the shortcomings of the existing technology and has good application prospects. DETAILED DESCRIPTION

[0026] In order to more clearly illustrate the technical solutions of the present invention, the following examples are given. Unless otherwise stated, the raw materials, reactions and post-processing methods mentioned in the examples are common raw materials on the market and technical methods well known to those skilled in the art.

[0027] The terms "preferred," "preferably," "more preferred," and the like, used herein, refer to embodiments of the invention that may provide certain benefits under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

[0028] It should be understood that, except in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending upon the desired properties to be obtained by the present invention.

[0029] The SAP resin in the embodiment of the present invention is the SAP super absorbent resin NR-760H produced by Shandong Noer Biotechnology Co., Ltd.

[0030] The polylactic acid in the examples of the present invention was purchased from Shenzhen Guanghua Weiye Co., Ltd.; and gelatin was purchased from Guangzhou Huayu Biotechnology Co., Ltd.

[0031] The preparation method of the modified polylactic acid in the embodiment of the present invention comprises the following steps:

[0032] S1. After dehydration by vacuum distillation of polylactic acid, the mixture was heated at 120° C. in vacuum for 2 h, and then 0.5 wt % of a catalyst (stannous chloride and p-toluenesulfonic acid in a molar ratio of 1:1) and pentaerythritol (polylactic acid:pentaerythritol=10:41, m / m) were added. The mixture was reacted at 145° C. for 2 h, and then the temperature was raised to 170° C. and the reaction was continued for 3 h to obtain hydroxy-terminated polylactic acid;

[0033] Using toluene as solvent, hydroxy-terminated polylactic acid, acrylic acid, p-toluenesulfonic acid and hydroquinone in a mass ratio of 60:19:0.3:0.09 were mixed and reacted at 120°C for 5 hours. The solvent was removed under reduced pressure to obtain acrylic acid-grafted polylactic acid;

[0034] S2. Add gelatin to water as the solvent and stir for 0.5 h. Adjust the pH to 7.5 with 2 mol / L NaOH solution, then add methacrylic anhydride (gelatin: methacrylic anhydride = 1:0.9, m / m). React at 4°C for 24 h. After dialysis for 3 days (KDa = 10,000), freeze-dry to obtain acrylic anhydride-modified gelatin.

[0035] S3. Using water as a solvent, the acrylic acid grafted polylactic acid, acrylic anhydride modified gelatin and N,N-methylenebisacrylamide in a mass ratio of 1:1:0.2 are mixed, and then 1 wt% of potassium persulfate by mass of the system is added. The mixture is reacted at 65° C. for 3 h under nitrogen protection, and the modified polylactic acid is obtained after centrifugation and drying.

[0036] The cellulose-chitosan composite in the embodiment of the present invention was prepared according to the method in “Zhao Hongkai, Zhang Kehan, Rui Shoupeng. Preparation and performance study of microcrystalline cellulose / chitosan water-absorbing materials [J]. New Chemical Materials, 2021(007):049.”

[0037] 10 g of microcrystalline cellulose, 12 g of NaIO4, and 10 g of NaCl were added to 500 mL of deionized water, stirred in the dark for 8 h, and then centrifuged, washed, and dried to obtain oxidized cellulose;

[0038] 1 g of NaOH was dissolved in a mixture of isopropanol (48 mL) and water (12 mL), and then 1 g of chitosan was added. After swelling at room temperature for 1 h, 1.5 g of chloroacetic acid (dissolved in 2 mL of isopropanol) was added and reacted for 12 h. The mixture was then washed and dried to obtain carboxymethyl chitosan.

[0039] Oxidized cellulose (1 wt% solution) and carboxymethyl chitosan (1 wt% solution) were mixed in a mass ratio of 1:3, stirred in a 60°C water bath for 1 h, and allowed to stand at room temperature for 6 h to form a cross-linked gel, which was then freeze-dried for 72 h and ground to obtain a cellulose-chitosan composite.

[0040] The auxiliary agent in the embodiment of the present invention is a nano silver antibacterial agent.

[0041] The “parts” in the embodiments of the present invention refer to parts by mass.

[0042] Example 1

[0043] An absorbent core with a SAP film structure, comprising, from top to bottom, an upper non-woven fabric layer, an absorbent layer, and a lower non-woven fabric layer;

[0044] The raw materials of the absorption layer include the following components in parts by mass:

[0045]

[0046] The method for preparing the absorbent core of the SAP film structure comprises the following steps:

[0047] According to the above-mentioned mass fractions, the modified polylactic acid, SAP resin, cellulose-chitosan composite and additives were evenly mixed and laid on the surface of the lower non-woven fabric layer, sprayed with deionized water to obtain an absorption layer with a thickness of 2 mm, and then the upper non-woven fabric layer was laid on the surface of the absorption layer. After drying, an absorption core with a SAP membrane structure was obtained.

[0048] Example 2

[0049] An absorbent core with a SAP film structure, comprising, from top to bottom, an upper non-woven fabric layer, an absorbent layer, and a lower non-woven fabric layer;

[0050] The raw materials of the absorption layer include the following components in parts by mass:

[0051]

[0052]

[0053] The method for preparing the absorbent core of the SAP film structure comprises the following steps:

[0054] According to the above-mentioned mass fractions, the modified polylactic acid, SAP resin, cellulose-chitosan composite and additives were evenly mixed and laid on the surface of the lower non-woven fabric layer, sprayed with deionized water to obtain an absorption layer with a thickness of 2 mm, and then the upper non-woven fabric layer was laid on the surface of the absorption layer. After drying, an absorption core with a SAP membrane structure was obtained.

[0055] Example 3

[0056] An absorbent core with a SAP film structure, comprising, from top to bottom, an upper non-woven fabric layer, an absorbent layer, and a lower non-woven fabric layer;

[0057] The raw materials of the absorption layer include the following components in parts by mass:

[0058]

[0059] The method for preparing the absorbent core of the SAP film structure comprises the following steps:

[0060] According to the above-mentioned mass fractions, the modified polylactic acid, SAP resin, cellulose-chitosan composite and additives were evenly mixed and laid on the surface of the lower non-woven fabric layer, sprayed with deionized water to obtain an absorption layer with a thickness of 2 mm, and then the upper non-woven fabric layer was laid on the surface of the absorption layer. After drying, an absorption core with a SAP membrane structure was obtained.

[0061] Comparative Example 1

[0062] An absorbent core with a SAP film structure. The difference between this comparative example and Example 1 is that the modified polylactic acid is replaced by a physical mixture of polylactic acid and gelatin in a mass ratio of 1:1. Other ingredients and preparation methods are the same as those in Example 1.

[0063] Comparative Example 2

[0064] An absorbent core with a SAP film structure. The difference between this comparative example and Example 1 is that the cellulose-chitosan composite is replaced with an equal mass of SAP resin. Other components and preparation methods are the same as those in Example 1.

[0065] Test Case

[0066] A performance comparison test was performed on Examples 1-3 and Comparative Examples 1-2.

[0067] Test method: GB / T14207-2008 was used to test water absorption and blood absorption.

[0068] The test results are shown in Table 1.

[0069] Table 1 Absorption performance test results

[0070] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Water absorption (g) 50.8 50.3 50.1 44.9 48.6 Artificial menstrual blood penetration time (s) 5.85 5.76 5.79 7.83 6.21 Artificial menstrual blood backflow volume (g) 0.69 0.72 0.71 1.67 0.98

[0071] According to Table 1, it can be concluded that the absorbent core of the SAP membrane structure prepared in the embodiment of the present invention has excellent absorption performance, a large water absorption capacity, a high absorption rate and a low rewet amount. However, in Comparative Examples 1-2, the polylactic acid was not modified, or the cellulose-chitosan composite was not used as a component, resulting in a decrease in the hydrophilicity of the material, making it difficult for the components to form a synergistic effect, and the absorption rate of the absorbent core was significantly reduced, the water absorption capacity decreased, and the rewet increased, and the ideal performance improvement could not be achieved.

[0072] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0073] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. An absorbent core with a SAP film structure, characterized in that: The absorbent core of the SAP membrane structure comprises, from top to bottom, an upper non-woven fabric layer, an absorbent layer and a lower non-woven fabric layer; The raw materials of the absorption layer include the following components in parts by mass: 20-50 parts of modified polylactic acid 10-20 parts of SAP resin 10-20 parts of cellulose-chitosan complex 0.5-5 parts of additives 10-50 parts of solvent; in, The modified polylactic acid is obtained by reacting acrylic anhydride-modified gelatin with acrylic acid-grafted polylactic acid; The preparation method of the modified polylactic acid comprises the following steps: S1, mixing hydroxy-terminated polylactic acid, acrylic acid, a catalyst and a polymerization inhibitor, and heating the mixture to react to obtain acrylic acid-grafted polylactic acid; S2, mixing gelatin and acrylic anhydride, and reacting at low temperature to obtain acrylic anhydride-modified gelatin; S3, mixing the acrylic acid grafted polylactic acid, acrylic anhydride modified gelatin, a crosslinking agent and an initiator, and heating the mixture under inert gas protection to obtain modified polylactic acid; The cellulose-chitosan composite is a mixture of oxidized cellulose and carboxymethyl chitosan; The mass ratio of the oxidized cellulose to the carboxymethyl chitosan is 1:(2-5); In step S1, the temperature of the heating reaction is 80-120°C; in step S2, the temperature of the low-temperature reaction is 0-5°C; in step S3, the temperature of the heating reaction is 60-90°C; In step S1, the mass ratio of the hydroxy-terminated polylactic acid to acrylic acid is 1:(0.1-0.5); In step S2, the mass ratio of gelatin to acrylic anhydride is 1:(0.5-2); In step S3, the mass ratio of the acrylic acid grafted polylactic acid to the acrylic anhydride modified gelatin is 1:(0.1-2).

2. The method for preparing the absorbent core of the SAP film structure according to claim 1, characterized in that: The steps include: Modified polylactic acid, SAP resin, cellulose-chitosan composite and additives are laid on the surface of the lower non-woven fabric layer, and a solvent is sprayed to obtain an absorption layer. Then, an upper non-woven fabric layer is laid on the surface of the absorption layer, and after drying, an absorption core with a SAP membrane structure is obtained.

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