Superabsorbent diaper and preparation method and application thereof

Abstract

The present application relates to a kind of superabsorbent paper diaper and its preparation method and application, including bottom film, core layer, face layer and elastic side seal, it is characterized in that, the core layer includes the following weight parts of preparation raw material: 50-60 parts acrylic water-absorbing resin, 20-30 parts polyacrylamide microspheres, 20-30 parts quaternary ammonium chitosan, 10-15 parts modifier and 1-5 parts catalyst;Wherein, the modifier is the combination of tartaric acid, 2-acrylamide-2-methylpropane sulfonic acid and N,N'-bis (acryloyl) cystamine with mass ratio 1: (2-3) : (1-1.5).Wherein, acrylic water-absorbing resin provides basic water-absorbing capacity, polyacrylamide microspheres enhance adsorption and prevent gel blockage, quaternary ammonium chitosan improves antibacterial properties and electrolyte adsorption capacity, catalyst ensures that reaction proceeds fully, modifier each component mutually synergistic enhances hydrophilicity, jointly improves the water-absorbing performance, structural stability and salt tolerance of core layer.

Description

Technical Field

[0001] The present invention relates to the technical field of adult diapers, and in particular to a superabsorbent diaper and a preparation method and application thereof. Background Art

[0002] In the current market landscape, superabsorbent resin, a widely used functional material, exhibits outstanding water absorption properties. The material itself exhibits excellent water absorption, capable of absorbing up to hundreds of times its own weight in water. This property makes it crucial in numerous applications requiring water absorption. However, when it comes to the specific scenario of absorbing urine, superabsorbent resin's performance is less than satisfactory. Its urine absorption capacity is relatively weak, typically absorbing only one-tenth of its water absorption capacity or even less.

[0003] To compensate for this shortcoming and meet the actual absorption requirements of the product, the industry currently generally adopts the method of increasing the filling amount of super absorbent resin. However, this approach will bring a series of new problems: from the perspective of product form, increasing the filling amount will inevitably make the product thicker and heavier. This not only affects the portability of the product and reduces the user's comfort, but also limits the application scenarios of the product to a certain extent. Moreover, products that are too thick often have obvious defects in absorption speed. Due to the increase in thickness, the diffusion and absorption path of the liquid inside the material becomes longer, resulting in a slower absorption speed and an inability to absorb the liquid in a timely and effective manner, which in turn affects the use effect of the product.

[0004] In view of the above problems, the industry currently urgently needs to improve the liquid absorption capacity of the composite core layer, especially to focus on improving its ability to absorb urine, so as to better meet market demand and improve the overall performance of the product. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a superabsorbent diaper and a preparation method and application thereof.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a superabsorbent diaper comprising a base film, a core layer, a surface layer and elastic side seals, wherein the core layer comprises the following raw materials in parts by weight: 50-60 parts of an acrylic water-absorbing resin, 20-30 parts of polyacrylamide microspheres, 20-30 parts of quaternized chitosan, 10-15 parts of a modifier and 1-5 parts of a catalyst; wherein the modifier is a composition of tartaric acid, 2-acrylamide-2-methylpropanesulfonic acid and N,N'-bis(acryloyl)cystamine in a mass ratio of 1:(2-3):(1-1.5).

[0008] In this invention, acrylic water-absorbing resin serves as the primary water-absorbing component. The carboxyl groups (-COOH) on its polymer chains can form hydrogen bonds with water molecules, thereby achieving efficient urine absorption. Polyacrylamide microspheres possess a three-dimensional network structure, and their internal pores can adsorb and store large amounts of urine. Furthermore, the amino and amide groups on the surface of the polyacrylamide microspheres interact with ions in urine, enhancing their water absorption. The positively charged quaternary ammonium groups in quaternized chitosan electrostatically adsorb negatively charged ions in urine, enhancing antibacterial properties while also promoting the adsorption of electrolytes in urine. Furthermore, the polyhydroxy structure of quaternized chitosan can form hydrogen bonds with urine molecules, enhancing water absorption.

[0009] In order to improve the compatibility of polyacrylamide microspheres and quaternized chitosan in the resin body, the present invention adds a modifier. The sulfonic acid group of 2-acrylamide-2-methylpropane sulfonic acid in the modifier has strong hydrophilicity and ionization ability, can effectively resist the inhibitory effect of salt ions on water absorption performance in urine, and its sulfonic acid group can form an ion pair with the quaternary ammonium group of chitosan, further improving the salt tolerance of the core layer. The tartaric acid in the modifier forms a hydrogen bond network with the hydroxyl group of the acrylic resin through the carboxyl group, further improving the network strength of the polymer, and it can also adjust the surface charge of the polyacrylamide microspheres to prevent it from agglomerating in the resin body. N, N'-bis (acryloyl) cystamine is a compound containing a double bond and a cystamine structure with good cross-linking properties. It can form crosslinking points in the polymer network, thereby improving the mechanical strength and salt tolerance of the polymer, and helping to maintain the structural stability of the core material after absorbing urine.

[0010] The cationic properties of quaternized chitosan and the anionic properties of acrylic resin form a polyelectrolyte complex, enhancing network stability through electrostatic attraction. Meanwhile, polyacrylamide microspheres, dispersed within the resin matrix, act as water storage units. Their porous structure rapidly absorbs liquid and stores it within the microspheres, while the resin network maintains overall structural strength.

[0011] Preferably, the catalyst is sodium hypophosphite and potassium persulfate in a mass ratio of 1:(0.5-1.5).

[0012] Specifically, the method for preparing the core layer comprises the following steps:

[0013] S1. Stir and disperse the quaternized chitosan in 2-3 times the amount of ethanol solution, mix thoroughly, introduce nitrogen into the reaction system, add a catalyst, continue stirring, then add polyacrylamide microspheres, acrylic acid water-absorbing resin and modifier, adjust the pH to 3-4, and stir the reaction at 50-60°C for 1-2h to obtain a slurry;

[0014] S2. The slurry is injected into a mold for molding to form a preform of an absorbent core layer, and then dried to obtain the core layer.

[0015] Preferably, in step S1, the volume concentration of the ethanol solution is 70-80%, and the stirring speed is 300-500 r / min.

[0016] Preferably, in step S2, the molding temperature is 80-90°C, the drying temperature is 100-120°C, and the drying time is 10-20 minutes.

[0017] Preferably, the surface layer is non-woven fabric.

[0018] Preferably, the base membrane is a PTFE microporous membrane.

[0019] Preferably, the elastic side seal is a non-woven fabric containing 20-30wt% spandex.

[0020] In a second aspect, the present invention provides a method for preparing the superabsorbent diaper according to the first aspect, comprising the following steps:

[0021] (1) Apply hot melt adhesive on the back of the surface layer and the front of the base film respectively, place the dried core layer between the surface layer and the base film, and perform hot pressing and lamination to obtain a semi-finished product;

[0022] (2) Cutting, folding, and edge pressing the semi-finished product, and adding elastic side seals to both side edges of the diaper to obtain the super absorbent diaper.

[0023] Preferably, the coating amount of the hot melt adhesive is 2-4 g / m 2 .

[0024] Preferably, the hot pressing temperature is 130-150° C., and the hot pressing pressure is 0.3-0.5 MPa.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The raw materials used in the superabsorbent diaper core layer work together through their unique chemical structures and functionalities to create a synergistic effect, resulting in superabsorbent urine. Specifically, the acrylic absorbent resin provides basic water absorption capacity, polyacrylamide microspheres enhance adsorption and prevent gel blocking, quaternized chitosan improves antibacterial properties and electrolyte adsorption, the catalyst ensures sufficient reaction, and the modifier components synergistically enhance hydrophilicity, collectively improving the core layer's water absorption, structural stability, and salt tolerance. DETAILED DESCRIPTION

[0027] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0028] The sources of raw materials used in the following examples and comparative examples are as follows:

[0029] Polyacrylamide microspheres: manufacturer is Xi'an Wande Energy Chemical Co., Ltd., model number is WQ50;

[0030] Acrylic water-absorbing resin: manufacturer is Shandong Linchuan Water Technology Co., Ltd., model number is lkh001;

[0031] Quaternized chitosan: CAS number is 70694-72-3;

[0032] Tartaric acid: CAS number is 133-37-9;

[0033] 2-Acrylamido-2-methylpropanesulfonic acid: CAS number is 15214-89-8;

[0034] N,N'-bis(acryloyl)cystamine: CAS number is 60984-57-8.

[0035] Unless otherwise specified, other materials, reagents, etc. used in the Examples and Comparative Examples can be obtained from commercial sources.

[0036] Example 1

[0037] A superabsorbent diaper comprising a base film, a core layer, a surface layer and elastic side seals; the surface layer is a non-woven fabric, the base film is a PTFE microporous membrane, and the elastic side seals are a non-woven fabric containing 25 wt% spandex;

[0038] The core layer comprises the following raw materials in parts by weight: 52 parts of acrylic water-absorbing resin, 25 parts of polyacrylamide microspheres, 22 parts of quaternized chitosan, 14 parts of a modifier, and 3 parts of a catalyst; wherein the modifier is tartaric acid, 2-acrylamide-2-methylpropanesulfonic acid, and N,N'-bis(acryloyl)cystamine in a mass ratio of 1:2.5:1.4, and the catalyst is sodium hypophosphite and potassium persulfate in a mass ratio of 1:1;

[0039] Specifically, the method for preparing the core layer comprises the following steps:

[0040] S1. The quaternized chitosan was dispersed in 2.5 times the volume of 75% ethanol solution at a stirring speed of 400 r / min. After thorough mixing, nitrogen was introduced into the reaction system, a catalyst was added, and stirring was continued at a speed of 400 r / min. Polyacrylamide microspheres, acrylic acid water-absorbing resin and modifier were added, and the pH was adjusted to 3. The mixture was stirred at 55° C. and a speed of 400 r / min for 1.5 h to obtain a slurry.

[0041] S2, injecting the slurry into a mold for molding to form a preform of the absorbent core layer, and drying to obtain the core layer; wherein the molding temperature is 85° C., the drying temperature is 100° C., and the drying time is 15 min;

[0042] The method for preparing the superabsorbent diaper comprises the following steps:

[0043] (1) Hot melt adhesive is applied on the back of the surface layer and the front of the base film respectively, and the dried core layer is placed between the surface layer and the base film, and hot pressing is performed to obtain a semi-finished product; wherein the hot pressing temperature is 140°C, the hot pressing pressure is 0.4 MPa, and the coating amount of the hot melt adhesive is 3 g / m 2 ;

[0044] (2) Cutting, folding, and edge pressing the semi-finished product, and adding elastic side seals to both side edges of the diaper to obtain the super absorbent diaper.

[0045] Example 2

[0046] A superabsorbent diaper comprising a base film, a core layer, a surface layer and elastic side seals; the surface layer is a non-woven fabric, the base film is a PTFE microporous membrane, and the elastic side seals are a non-woven fabric containing 20 wt% spandex;

[0047] The core layer comprises the following raw materials in parts by weight: 50 parts of acrylic water-absorbing resin, 20 parts of polyacrylamide microspheres, 20 parts of quaternized chitosan, 10 parts of a modifier, and 1 part of a catalyst; wherein the modifier is tartaric acid, 2-acrylamide-2-methylpropanesulfonic acid, and N,N'-bis(acryloyl)cystamine in a mass ratio of 1:2:1, and the catalyst is sodium hypophosphite and potassium persulfate in a mass ratio of 1:0.5;

[0048] Specifically, the method for preparing the core layer comprises the following steps:

[0049] S1. The quaternized chitosan was dispersed in 2 times the volume of 70% ethanol solution at a speed of 300 r / min, and after being thoroughly mixed, nitrogen was introduced into the reaction system, a catalyst was added, and stirring was continued at a speed of 300 r / min. Then, polyacrylamide microspheres, acrylic acid water-absorbing resin and modifier were added, and the pH was adjusted to 3. The mixture was stirred at 50° C. and 300 r / min for 2 h. After the reaction, a slurry was obtained;

[0050] S2, injecting the slurry into a mold for molding to form a preform of the absorbent core layer, and drying to obtain the core layer; wherein the molding temperature is 80° C., the drying temperature is 100° C., and the drying time is 20 min;

[0051] The method for preparing the superabsorbent diaper comprises the following steps:

[0052] (1) Hot melt adhesive is applied on the back of the surface layer and the front of the base film respectively, and the dried core layer is placed between the surface layer and the base film, and hot pressing is performed to obtain a semi-finished product; wherein the hot pressing temperature is 130°C, the hot pressing pressure is 0.3 MPa, and the coating amount of the hot melt adhesive is 2 g / m 2 ;

[0053] (2) Cutting, folding, and edge pressing the semi-finished product, and adding elastic side seals to both side edges of the diaper to obtain the super absorbent diaper.

[0054] Example 3

[0055] A superabsorbent diaper comprising a base film, a core layer, a surface layer and elastic side seals; the surface layer is a non-woven fabric, the base film is a PTFE microporous membrane, and the elastic side seals are non-woven fabric containing 30 wt% spandex;

[0056] The core layer comprises the following raw materials in parts by weight: 60 parts of acrylic water-absorbing resin, 30 parts of polyacrylamide microspheres, 30 parts of quaternized chitosan, 15 parts of a modifier, and 5 parts of a catalyst; wherein the modifier is tartaric acid, 2-acrylamide-2-methylpropanesulfonic acid, and N,N'-bis(acryloyl)cystamine in a mass ratio of 1:3:1.5, and the catalyst is sodium hypophosphite and potassium persulfate in a mass ratio of 1:1.5;

[0057] Specifically, the method for preparing the core layer comprises the following steps:

[0058] S1. The quaternized chitosan was dispersed in 3 times the volume of 80% ethanol solution at a speed of 500 r / min, and after thorough mixing, nitrogen was introduced into the reaction system, a catalyst was added, and stirring was continued at a speed of 500 r / min. Then, polyacrylamide microspheres, acrylic acid water-absorbing resin and modifier were added, and the pH was adjusted to 4. The mixture was stirred at 60° C. and 500 r / min for 1 h to obtain a slurry;

[0059] S2, injecting the slurry into a mold for molding to form a preform of the absorbent core layer, and drying to obtain the core layer; wherein the molding temperature is 90° C., the drying temperature is 120° C., and the drying time is 10 minutes;

[0060] The method for preparing the superabsorbent diaper comprises the following steps:

[0061] (1) Hot melt adhesive is applied on the back of the surface layer and the front of the base film respectively, and the dried core layer is placed between the surface layer and the base film, and hot pressing is performed to obtain a semi-finished product; wherein the hot pressing temperature is 130-150°C, the hot pressing pressure is 0.3-0.5MPa; the coating amount of the hot melt adhesive is 4g / m2 ;

[0062] (2) Cutting, folding, and edge pressing the semi-finished product, and adding elastic side seals to both side edges of the diaper to obtain the super absorbent diaper.

[0063] Comparative Example 1

[0064] The difference between Comparative Example 1 and Example 1 is that the amount of modifier added remains unchanged, tartaric acid is not added, and 2-acrylamide-2-methylpropanesulfonic acid and N,N'-bis(acryloyl)cystamine in a mass ratio of 2.5:1.4 are used to make up for the missing amount.

[0065] Comparative Example 2

[0066] Comparative Example 2 differs from Example 1 in that the amount of modifier added remains unchanged, 2-acrylamide-2-methylpropanesulfonic acid is not added, and tartaric acid and N,N'-bis(acryloyl)cystamine in a mass ratio of 1:1.4 are used to make up for the missing amount.

[0067] Comparative Example 3

[0068] Comparative Example 3 differs from Example 1 in that the amount of modifier added remains unchanged, N,N'-bis(acryloyl)cystamine is not added, and tartaric acid and 2-acrylamide-2-methylpropanesulfonic acid in a mass ratio of 1:2.5 are used to make up for the missing amount.

[0069] Comparative Example 4

[0070] The difference between Comparative Example 4 and Example 1 is that the amount of the modifier added remains unchanged, and the mass ratio of tartaric acid, 2-acrylamide-2-methylpropanesulfonic acid and N,N'-bis(acryloyl)cystamine is 2.5:1:1.4.

[0071] Comparative Example 5

[0072] The difference between Comparative Example 5 and Example 1 is that the amount of the modifier added remains unchanged, and the mass ratio of tartaric acid, 2-acrylamide-2-methylpropanesulfonic acid and N,N'-bis(acryloyl)cystamine is 1:1.4:2.5.

[0073] Performance Testing

[0074] The absorption effect of the diaper is based on the liquid absorption performance of the core layer. Therefore, in order to more intuitively reflect the liquid absorption performance of the diaper, the core layers prepared in Examples 1-3 and Comparative Examples 1-5 were subjected to the following performance tests:

[0075] (1) Water absorption rate and physiological saline absorption test: Cut the core layer of each group into samples with a length of 2 cm, a width of 2 cm, and a thickness of 0.5 cm. Immerse each group of samples in deionized water and physiological saline (containing 0.9% sodium chloride) respectively. When the liquid is fully absorbed and equilibrium is reached, hang and let it stand for 30 minutes to remove the unabsorbed water or physiological saline, and then weigh the mass of the core layer. The water absorption rate and physiological saline absorption rate are calculated according to the formula Q = (m1-m2) / m2, where m1 is the mass of the core layer after liquid absorption and m2 is the mass of the core layer before liquid absorption. The arithmetic mean of the three measurement results is taken as the measurement result, and the data results are shown in Table 1.

[0076] (2) Absorption rate test: 100 mL of deionized water was placed in a beaker. A magnetic rotor was placed in the beaker and placed on a magnetic stirrer. The speed was adjusted to 600 r / min. The core layer of each group was cut into samples with a length of 2 cm, a width of 2 cm, and a thickness of 0.5 cm. The samples were then poured into the vortex. The vortex began to disappear while absorbing deionized water. The time required for the liquid surface to reach a stationary state was measured as the water absorption rate. The data results are shown in Table 1.

[0077] (3) Reverse osmosis test: The core layer of each group was cut into samples with a length of 2 cm, a width of 2 cm, and a thickness of 0.5 cm. Each group of samples was immersed in deionized water and placed at 25°C and 70% (relative humidity) for 1 hour. After being taken out, a piece of filter paper was placed on the surface of the sample, and the mass was recorded as m1. A 250g weight was used to press the sample for 6 hours. After 6 hours, the weight of the filter paper was measured as m2. The reverse osmosis amount was calculated as m2-m1. The data results are shown in Table 1.

[0078] Table 1 Core layer performance test results of each group

[0079] Group / property Water absorption (g / g) Saline absorption (g / g) Water absorption speed (s) Osmotic amount (g) Example 1 272 56 5 0.32 Example 2 264 51 7 0.35 Example 3 278 59 5 0.31 Comparative Example 1 175 33 16 1.20 Comparative Example 2 170 31 18 1.25 Comparative Example 3 178 36 15 1.18 Comparative Example 4 234 40 13 0.91 Comparative Example 5 238 43 12 0.87

[0080] As shown in Table 1, in combination with Example 1 and Comparative Examples 1-3, the modifier of Example 1 is a compound of tartaric acid, 2-acrylamide-2-methylpropanesulfonic acid and N, N'-bis (acryloyl) cystamine, and its core layer absorption performance is better than that of Comparative Examples 1-3. This may be because the sulfonic acid group of 2-acrylamide-2-methylpropanesulfonic acid has strong hydrophilicity and ionization ability, which can effectively resist the inhibitory effect of salt ions on water absorption performance in urine, and N, N'-bis (acryloyl) cystamine is a compound containing a double bond and a cystamine structure. , has good cross-linking properties, which can form cross-linking points in the polymer network, thereby improving the mechanical strength and salt resistance of the polymer. The tartaric acid in the modifier forms a hydrogen bond network with the hydroxyl group of the acrylic resin through the carboxyl group, further improving the network strength of the polymer. It can also adjust the surface charge of the polyacrylamide microspheres to prevent them from agglomerating in the resin body. Therefore, the combination of tartaric acid, 2-acrylamide-2-methylpropanesulfonic acid and N,N'-bis(acryloyl)cystamine can synergistically improve the absorption performance and salt resistance of the core layer.

[0081] Combining the data of Example 1 and Comparative Examples 4-5, it can be seen that when the mass ratio of tartaric acid, 2-acrylamide-2-methylpropanesulfonic acid and N,N'-bis(acryloyl)cystamine is 1:(2-3):(1-1.5), the absorption performance of the core layer reaches a better level.

[0082] In summary, the modifiers in the core layer of the diaper of the present invention work together to enhance the hydrophilicity and jointly improve the water absorption performance, structural stability and salt resistance of the core layer.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A super absorbent diaper comprising a base film, a core layer, a surface layer and elastic side seals, characterized in that: The core layer comprises the following raw materials in parts by weight: 50-60 parts of acrylic water-absorbing resin, 20-30 parts of polyacrylamide microspheres, 20-30 parts of quaternized chitosan, 10-15 parts of a modifier, and 1-5 parts of a catalyst; wherein the modifier is a composition of tartaric acid, 2-acrylamide-2-methylpropanesulfonic acid, and N,N'-bis(acryloyl)cystamine in a mass ratio of 1:(2-3):(1-1.5); and the catalyst is sodium hypophosphite and potassium persulfate in a mass ratio of 1:(0.5-1.5); The method for preparing the core layer comprises the following steps: S1. Stir and disperse the quaternized chitosan in 2-3 times the amount of ethanol solution, mix thoroughly, introduce nitrogen into the reaction system, add a catalyst, continue stirring, then add polyacrylamide microspheres, acrylic acid water-absorbing resin and modifier, adjust the pH to 3-4, and stir the reaction at 50-60°C for 1-2h to obtain a slurry; S2. The slurry is injected into a mold for molding to form a preform of an absorbent core layer, and then dried to obtain the core layer.

2. The superabsorbent diaper according to claim 1, wherein: In the core layer preparation step S2, the molding temperature is 80-90°C, the drying temperature is 100-120°C, and the drying time is 10-20 minutes.

3. The superabsorbent diaper according to claim 1, wherein: The surface layer is non-woven fabric.

4. The superabsorbent diaper according to claim 1, wherein: The base membrane is a PTFE microporous membrane.

5. The superabsorbent diaper according to claim 1, wherein: The elastic side seal is a non-woven fabric containing 20-30wt% spandex.

6. The method for preparing the superabsorbent diaper according to any one of claims 1 to 5, characterized in that: The following steps are involved: Hot melt adhesive is applied to the back of the surface layer and the front of the base film respectively, and the dried core layer is placed between the surface layer and the base film, and hot pressing is performed to obtain a semi-finished product; The semi-finished product is cut, folded, and edge pressed, and elastic side seals are added to both side edges of the diaper to obtain the super absorbent diaper.

7. The method for preparing superabsorbent diapers according to claim 6, wherein: The temperature of hot pressing is 130-150° C., and the pressure of hot pressing is 0.3-0.5 MPa.