High-performance moisturizing film and method for preparing the same

Abstract

The application belongs to the technical field of packaging and specifically relates to a high-performance moisturizing adhesive film and a preparation method thereof. The moisturizing adhesive film contains the following components in mass percentage: 1.5-2% of alginate, 0.1-0.25% of konjac gum, 0.3-0.5% of plasticizer, 0.15-0.25% of sodium carboxymethyl cellulose, 0.1-0.2% of carboxymethyl chitosan, 0.1-0.2% of sunflower seed oil, 0.1-0.2% of emulsifier, and the balance of water. The application provides a high-performance moisturizing adhesive film and a preparation method thereof in view of the problem that the mechanical property of the alginate-based adhesive film is significantly reduced after the addition of sunflower seed oil in the prior art. The adhesive film is prepared by the selection and ratio optimization of specific components, has high tensile strength while maintaining excellent moisturizing property, and solves the technical problem of mechanical property deterioration caused by the addition of sunflower seed oil.

Description

Technical Field

[0001] This invention belongs to the field of packaging technology, specifically relating to a high-performance moisturizing film and its preparation method. Background Technology

[0002] Alginate, a natural anionic polysaccharide extracted from brown algae, possesses excellent film-forming properties, biocompatibility, biodegradability, and gelation characteristics, and is widely used in edible packaging films, food coatings, fruit and vegetable preservation, and biomedical materials. However, the alginate molecular chain contains a large number of hydrophilic groups (hydroxyl and carboxyl groups), resulting in films made solely from alginate exhibiting poor moisture retention, easy dehydration and brittleness, and insufficient flexibility, severely limiting its application in high-humidity environments. Especially in food packaging and fruit and vegetable preservation, the moisture retention performance of the film directly affects the moisture retention and quality maintenance of the packaged goods, and is one of the core indicators for evaluating film performance.

[0003] To improve the moisturizing performance of alginate membranes, various technical approaches have been explored. Among these, adding hydrophobic oils to reduce water vapor permeability is one of the most common and effective methods. Oils (such as vegetable oils, fatty acids, and their derivatives) possess natural hydrophobic properties. Introducing them into a hydrophilic polysaccharide network can form tiny hydrophobic regions or physical barrier layers within the membrane, significantly increasing the tortuosity of the path through which water molecules penetrate the membrane, thereby effectively reducing water vapor permeability. Sunflower seed oil is a widely used vegetable oil, rich in unsaturated fatty acids (approximately 50-70% linoleic acid and 20-30% oleic acid), and possesses good flowability and hydrophobic properties. Previous studies have reported the use of vegetable oils such as sunflower seed oil to improve the moisture barrier properties of alginate membranes. The uniform dispersion of the oils reduces the water vapor permeability coefficient of the membrane to a certain extent, thus enhancing the membrane's moisturizing ability.

[0004] However, while the addition of sunflower seed oil improves moisturizing properties, it also introduces new technical challenges: Because sunflower seed oil molecules, as hydrophobic small molecules, insert themselves between alginate molecular chains, they occupy space that would otherwise be used for intermolecular interactions within the polymer network. This weakens the hydrogen bonding and intermolecular forces between alginate chains, leading to a looser network structure in the film. Macroscopically, this manifests as a significant decrease in tensile strength, increased brittleness, and susceptibility to breakage, resulting in reduced processing and handling performance. This contradiction essentially reflects the trade-off between the moisturizing properties and mechanical properties of the film: improving the moisture barrier properties of a hydrophilic network often requires the introduction of hydrophobic components, but the introduction of hydrophobic components inevitably disrupts the structural integrity of the hydrophilic network. When the amount of sunflower seed oil added is low, the improvement in moisturizing performance is not significant; when the amount added is increased to a level that effectively improves moisturizing performance, the mechanical properties fail to meet the requirements of practical applications. This technical contradiction restricts the practical application of sunflower seed oil in alginate-based films.

[0005] To address the aforementioned issues, those skilled in the art have explored various technical solutions. For example, adding inorganic or organic nanofillers such as nanocellulose and montmorillonite can enhance the mechanical properties of alginate membranes. Another approach is to strengthen the network structure by increasing the alginate concentration or the amount of crosslinking agent; however, this often leads to decreased membrane flexibility and increased brittleness, and excessive crosslinking can make the membrane too stiff and affect its feel. Yet another approach involves combining alginate with other polysaccharides (such as starch and carrageenan), which can improve mechanical properties to some extent. However, conventional single-polysaccharide formulations are insufficient to effectively counteract the destructive effects of lipids on the network structure, especially in the presence of lipids, where the hydrogen bonding interactions between polysaccharides are easily weakened by lipid molecules.

[0006] Therefore, developing a food-grade alginate-based film that can fully utilize the moisturizing effects of sunflower seed oil while effectively maintaining or even improving its mechanical properties is of significant practical value and technical challenge, and is also a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] This invention addresses the shortcomings of existing alginate-based films, where the addition of sunflower seed oil improves moisturizing performance but significantly reduces mechanical properties. It provides a high-performance moisturizing film and its preparation method. Through the selection and optimization of specific components, this film maintains excellent moisturizing performance while exhibiting high tensile strength, thus solving the technical problem of mechanical property degradation caused by the addition of sunflower seed oil.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A high-performance moisturizing film, the raw materials of which include the following components: Alginate 1.5-2%, konjac gum 0.1-0.25%, plasticizer 0.3-0.5%, sodium carboxymethyl cellulose 0.15-0.25%, carboxymethyl chitosan 0.1-0.2%, sunflower seed oil 0.1-0.2%, emulsifier 0.1-0.2%, balance water.

[0009] Alginate, a common hydrophilic polymer, has poor moisturizing ability. The addition of sunflower seed oil improves its moisturizing ability. However, unlike other vegetable oils such as olive oil, soybean oil, and palm oil, sunflower seed oil has unique fatty acid composition characteristics (linoleic acid content of about 50-70% and oleic acid content of about 20-30%). Moreover, it has high unsaturation and relatively concentrated carbon chain length distribution, making it prone to oxidative cross-linking or migration and aggregation during film formation and drying. This has a specific impact on the alginate network structure, easily leading to a decrease in the mechanical properties of the film and limited improvement in moisturizing performance.

[0010] To address the problems caused by adding sunflower seed oil to alginate, this invention specifically adds a certain amount of sodium carboxymethyl cellulose and carboxymethyl chitosan. Although both sodium carboxymethyl cellulose and carboxymethyl chitosan are polysaccharides derived from alginate, their molecular structures and functions differ significantly. Sodium carboxymethyl cellulose is a carboxymethylated derivative of cellulose, with a linear molecular chain containing a large number of carboxymethyl and hydroxyl groups. Both sodium carboxymethyl cellulose and alginate are anionic polysaccharides with high molecular structural similarity, primarily interacting through hydrogen bonds. The sodium carboxymethyl cellulose molecular chain can embed itself within the alginate network, filling gaps between molecular chains, increasing the density of physical cross-linking points, and providing skeletal support. Carboxymethyl chitosan, on the other hand, is a carboxymethylated derivative of chitosan, containing amino, carboxyl, and hydroxyl groups simultaneously in its molecular chain, making it an amphoteric polysaccharide. Carboxymethyl chitosan can form an electrostatic attraction with alginate. This electrostatic interaction is stronger than simple hydrogen bonding, allowing for a more robust bond between carboxymethyl chitosan and alginate.

[0011] Furthermore, the simultaneous addition of sodium carboxymethyl cellulose and carboxymethyl chitosan enhances the moisturizing effect. Sodium carboxymethyl cellulose molecules contain numerous carboxymethyl and hydroxyl groups, exhibiting excellent hydrophilicity and water-retention capacity; carboxymethyl chitosan molecules contain amino, carboxyl, and hydroxyl groups, forming multiple water-binding sites. The synergistic effect of these two molecules constructs a triple moisturizing network within the alginate network: sodium carboxymethyl cellulose provides a long-lasting water-retaining matrix, while carboxymethyl chitosan provides additional water molecule binding sites and slows down water molecule migration. This combined effect significantly improves the moisturizing rate of the film compared to films with either sodium carboxymethyl cellulose or carboxymethyl chitosan alone. Additionally, the insertion of sunflower seed oil weakens the direct interactions between alginate chains, while the addition of sodium carboxymethyl cellulose and carboxymethyl chitosan repairs the weakened network regions, ensuring that oil droplets are encapsulated within the enhanced network rather than remaining outside of it, further enhancing the moisturizing ability of sunflower seed oil. Overall, compared to ordinary chitosan and cellulose, carboxymethylation of carboxymethyl chitosan and sodium carboxymethyl cellulose not only improves their dispersibility in water, but also enhances their interaction with the matrix alginate and sunflower seed oil by introducing active groups, thereby improving the stability of the film.

[0012] In one embodiment, the alginate is one or more of sodium alginate and potassium alginate. Sodium alginate and potassium alginate are the sodium and potassium salts of alginic acid, respectively, both exhibiting good water solubility and film-forming properties. Their molecular structures are similar, allowing them to undergo ionic cross-linking with calcium ions to form an "egg-box" structure. Specifically, sodium alginate can be selected as the raw material.

[0013] In one embodiment, the plasticizer is one or more of glycerol, sorbitol, oleic acid, and stearic acid. The mechanism of action of the plasticizer is to insert itself between polymer molecular chains, weaken interchain hydrogen bonds and van der Waals forces, increase the degree of freedom of chain segment movement, thereby improving the flexibility and elongation at break of the film.

[0014] In one embodiment, the emulsifier is one or more of Tween-20 and Tween-80. The Tween series (polysorbates) are nonionic surfactants whose molecular structure contains hydrophilic polyoxyethylene segments and hydrophobic fatty acid segments. In the alginate-sunflower oil-water three-phase system, Tween molecules can be directionally adsorbed at the oil-water interface, with the hydrophilic end extending into the aqueous phase and the hydrophobic end extending into the oil phase, significantly reducing interfacial tension. This allows sunflower oil to be stably dispersed in the aqueous alginate solution as small, uniform droplets, preventing droplet aggregation and stratification.

[0015] In one embodiment, the amount of alginate used can be 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2%. Further, the amount of alginate used can be 1.6-1.9%. Appropriate amounts of alginate can better form coordination crosslinking sites with calcium ions. This ionic crosslinking network provides basic mechanical support and water insolubility for the film, thus playing a role in skeletal reinforcement.

[0016] In one embodiment, the amount of konjac gum can be 0.1%, 0.12%, 0.14%, 0.16%, 0.18%, 0.2%, 0.22%, or 0.25%. Further, the amount of konjac gum can be 0.14%-0.22%. The long-chain molecular structure of konjac gum can simultaneously form hydrogen bonds with multiple alginate molecular chains, connecting different segments in the alginate network and increasing the overall cohesive energy and toughness of the network. At the same time, an appropriate amount of konjac gum can avoid the problem of uneven component dispersion caused by excessive dosage, and can also reduce the movement rate of sunflower seed oil droplets, assisting the emulsifier in stabilizing the oil-water system, reducing the migration and aggregation of oil droplets during the drying process, thereby helping sunflower seed oil improve its moisturizing ability.

[0017] In one embodiment, the amount of plasticizer can be 0.3%, 0.35%, 0.4%, 0.45%, or 0.5%. Further, the amount of plasticizer can be 0.35-0.45%. An appropriate amount of plasticizer can better weaken interchain hydrogen bonds and van der Waals forces, increase the degree of freedom of chain segment movement, thereby improving the flexibility and elongation at break of the film.

[0018] In one embodiment, the amount of sodium carboxymethyl cellulose can be 0.15%, 0.18%, 0.2%, 0.22%, or 0.25%; the amount of carboxymethyl chitosan can be 0.1%, 0.12%, 0.14%, 0.16%, 0.18%, or 0.2%. Further, the amount of sodium carboxymethyl cellulose can be 0.18-0.22%; the amount of carboxymethyl chitosan can be 0.12-0.18%.

[0019] In one embodiment, the amount of sunflower seed oil can be 0.1%, 0.12%, 0.14%, 0.16%, 0.18%, or 0.2%. Further, the amount of sunflower seed oil can be 0.12-0.18%. An appropriate amount of sunflower seed oil can improve the moisturizing ability of alginate while avoiding excessive oil leading to reduced film uniformity, which is detrimental to the improvement of mechanical and barrier properties.

[0020] In one embodiment, the high-performance moisturizing film comprises the following components: 1.5-2% alginate, 0.15-0.2% konjac gum, 0.35-0.45% plasticizer, 0.18-0.25% sodium carboxymethyl cellulose, 0.1-0.16% carboxymethyl chitosan, 0.1-0.2% sunflower seed oil, 0.1-0.16% emulsifier, and the balance being water. Adjusting the amount of each component can better improve the mechanical and moisturizing properties of the film. Specifically, the content of sodium carboxymethyl cellulose in the film is greater than the content of carboxymethyl chitosan. This is because when the content of sodium carboxymethyl cellulose is higher, the anionic polysaccharides in the system are dominant. Sodium carboxymethyl cellulose and carboxymethyl chitosan have good compatibility with the alginate matrix, and the two synergistically fill the alginate network, making it easier to form a uniform and dense composite network structure. If the content of carboxymethyl chitosan is higher than that of sodium carboxymethyl cellulose, it is easy to cause excessively high local charge density, which leads to electrostatic repulsion between molecular chains, thereby destroying the uniformity and density of the alginate matrix and also hindering the improvement of moisturizing performance.

[0021] On the other hand, the present invention also provides a method for preparing a high-performance moisturizing film, comprising the following steps: (1) Dissolve and disperse alginate, konjac gum, plasticizer, sodium carboxymethyl cellulose and carboxymethyl chitosan in water, then add sunflower seed oil and emulsifier, disperse evenly to obtain film-forming solution; (2) The film-forming solution is cast into a film, which is then dried, cross-linked, and equilibrated to obtain a high-performance moisturizing film. This film, through the compounding of sodium carboxymethyl cellulose and carboxymethyl chitosan, maintains excellent moisturizing properties while possessing high tensile strength and good flexibility, thus solving the technical problem of mechanical property degradation caused by the addition of sunflower seed oil. In particular, appropriate heat treatment can be performed to accelerate the dissolution rate of each raw material component. It should be noted that this invention is designed based on the interaction mechanism between the specific molecular structure of sunflower seed oil and the alginate complex polysaccharide network. Other vegetable oils (such as olive oil, soybean oil, palm oil, corn oil, etc.) cannot achieve similar technical effects in the system of this invention due to the significant differences in their fatty acid composition and physicochemical properties. The reason for this is that sunflower seed oil has a moderate molecular length and a certain curved conformation, which happens to match the micro-area size and polar environment of the network composed of alginate, konjac gum, sodium carboxymethyl cellulose, and carboxymethyl chitosan. Oil molecules can be stably fixed through hydrophobic interactions and van der Waals forces. Simultaneously, a small number of polar groups (ester bonds) in the oil molecules also form additional hydrogen bonds with the hydroxyl groups on the network, further enhancing stability. In particular, the film-forming solution prepared by this invention can also be directly added to substances such as collagen groups, or applied to the surface of packaging materials such as sausage casings to impart barrier and moisturizing properties.

[0022] In one embodiment, the uniform dispersion is achieved using an ultrasonic process. Compared to high-speed shearing or mechanical stirring, ultrasonic dispersion is more efficient and produces a more uniform dispersion. It also removes air bubbles from the film-forming solution, reducing internal defects in the film.

[0023] In one embodiment, the drying is carried out in an oven at a temperature of 35-45°C. Oven drying achieves uniform evaporation of moisture from the film-forming solution through convective heating. The drying temperature of 35-45°C represents optimized, mild drying conditions: too low a temperature results in low efficiency; too high a temperature leads to excessively rapid evaporation, potentially causing a film to form on the membrane surface while preventing internal moisture from escaping, resulting in bubbles and cracks. Furthermore, rapid evaporation is detrimental to the orderly arrangement and network reconstruction of alginate molecules, affecting the film's density and mechanical properties.

[0024] In one embodiment, the crosslinking is performed using a calcium chloride solution. Specifically, a 1-10% calcium chloride solution can be used. The crosslinking time is not particularly limited, generally 1-10 minutes is sufficient. Further, after crosslinking, the film is obtained by washing and drying. Washing removes residual components from the film surface, preventing the precipitation of white crystals after drying, which would affect the appearance and feel of the film.

[0025] In one embodiment, the balancing process involves placing the membrane in a constant temperature and humidity chamber (e.g., 25°C, 50% relative humidity) for 40-60 hours. Placing the membrane under constant temperature and humidity conditions for 40-60 hours allows for a uniform distribution of moisture within the membrane, while simultaneously enabling the hydrogen bonds and electrostatic interactions between components such as alginate and konjac gum to reach thermodynamic equilibrium, eliminating internal stress and stabilizing the mechanical and moisturizing properties of the membrane.

[0026] Beneficial effects: (1) By adding sunflower seed oil, the present invention effectively reduces the water vapor permeability of the film and significantly improves the moisturizing performance of the film. As a hydrophobic substance, sunflower seed oil is uniformly dispersed in the alginate network structure under the action of emulsifier, forming tiny hydrophobic oil droplets, which physically block the penetration and migration channels of water molecules, thereby reducing the water vapor permeability of the film and increasing the moisturizing rate.

[0027] (2) By combining sodium carboxymethyl cellulose and carboxymethyl chitosan, and with the network-reinforcing effect of konjac gum, the decrease in mechanical properties caused by the addition of sunflower seed oil is effectively compensated. These three compounds, along with alginate, work synergistically through multiple non-covalent bonds to construct a dense and stable three-dimensional network structure, effectively counteracting the weakening effect of sunflower seed oil on the inter-chain forces of the polymer. In this invention, the simultaneous addition of sodium carboxymethyl cellulose and carboxymethyl chitosan can construct a hydrophilic-water-retaining-water-locking triple moisturizing network within the alginate network, producing a synergistic moisturizing effect. Detailed Implementation

[0028] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0029] Performance Testing: The performance of the high-performance moisturizing films prepared in Examples 1-10 and Comparative Examples 1-4 was tested under the same conditions. Specifically, the tensile strength (MPa) of the films was tested using a texture analyzer, and the water vapor transmission coefficient (g·mm / (m)) was determined using the pseudo-cup method. 2 ·d·kPa).

[0030] Example 1

[0031] A high-performance moisturizing film, by weight percentage, comprises the following components: Sodium alginate 1.5%, konjac gum 0.22%, glycerin 0.3%, sodium carboxymethyl cellulose 0.25%, carboxymethyl chitosan 0.1%, sunflower seed oil 0.1%, Tween-20 0.1%, balance water.

[0032] The method for preparing a high-performance moisturizing film includes the following steps: (1) Dissolve and disperse sodium alginate, konjac gum, glycerin, sodium carboxymethyl cellulose and carboxymethyl chitosan in water, then add sunflower seed oil and Tween-20, and ultrasonically disperse evenly to obtain film-forming solution; (2) The film-forming solution was cast into a film, dried in an oven at 40°C for 7 hours, then crosslinked with a 4% calcium chloride solution for 4 minutes, washed and dried again, and equilibrated in a constant temperature and humidity chamber for 48 hours to obtain a high-performance moisturizing film. The tensile strength was tested to be 55.72 MPa; the water vapor transmission coefficient was 1.26 g·mm / (m²). 2 ·d·kPa).

[0033] Example 2

[0034] A high-performance moisturizing film, by weight percentage, comprises the following components: Sodium alginate 2%, konjac gum 0.1%, glycerin 0.5%, sodium carboxymethyl cellulose 0.16%, carboxymethyl chitosan 0.16%, sunflower seed oil 0.18%, Tween-20 0.2%, balance water.

[0035] The method for preparing a high-performance moisturizing film includes the following steps: (1) Dissolve and disperse sodium alginate, konjac gum, glycerin, sodium carboxymethyl cellulose and carboxymethyl chitosan in water, then add sunflower seed oil and Tween-20, and ultrasonically disperse evenly to obtain film-forming solution; (2) The film-forming solution was cast into a film, dried in an oven at 45°C for 6 hours, then crosslinked with a 4% calcium chloride solution for 4 minutes. After washing and drying again, the film was equilibrated in a constant temperature and humidity chamber for 48 hours to obtain a high-performance moisturizing film. The tensile strength was tested to be 59.83 MPa, and the water vapor transmission coefficient was 1.27 g·mm / (m). 2 ·d·kPa).

[0036] Example 3

[0037] A high-performance moisturizing film, by weight percentage, comprises the following components: Sodium alginate 1.8%, konjac gum 0.18%, glycerin 0.4%, sodium carboxymethyl cellulose 0.15%, carboxymethyl chitosan 0.2%, sunflower seed oil 0.16%, Tween-20 0.15%, balance water.

[0038] The method for preparing a high-performance moisturizing film includes the following steps: (1) Dissolve and disperse sodium alginate, konjac gum, glycerin, sodium carboxymethyl cellulose and carboxymethyl chitosan in water, then add sunflower seed oil and Tween-20, and ultrasonically disperse evenly to obtain film-forming solution; (2) The film-forming solution was cast into a film, dried in an oven at 40°C for 7 hours, then crosslinked with a 4% calcium chloride solution for 4 minutes. After washing and drying again, the film was equilibrated in a constant temperature and humidity chamber for 48 hours to obtain a high-performance moisturizing film. The tensile strength was tested to be 58.23 MPa, and the water vapor transmission coefficient was 1.32 g·mm / (m). 2 ·d·kPa).

[0039] Example 4

[0040] A high-performance moisturizing film, by weight percentage, comprises the following components: Sodium alginate 1.5%, konjac gum 0.12%, glycerin 0.33%, sodium carboxymethyl cellulose 0.18%, carboxymethyl chitosan 0.13%, sunflower seed oil 0.13%, Tween-20 0.12%, balance water.

[0041] The method for preparing a high-performance moisturizing film includes the following steps: (1) Dissolve and disperse sodium alginate, konjac gum, glycerin, sodium carboxymethyl cellulose and carboxymethyl chitosan in water, then add sunflower seed oil and Tween-20, and ultrasonically disperse evenly to obtain film-forming solution; (2) The film-forming solution was cast into a film, dried in an oven at 43°C for 7 hours, then crosslinked with a 4% calcium chloride solution for 4 minutes, washed and dried again, and equilibrated in a constant temperature and humidity chamber for 48 hours to obtain a high-performance moisturizing film. The tensile strength was tested to be 57.84 MPa; the water vapor transmission coefficient was 1.20 g·mm / (m²). 2 ·d·kPa).

[0042] Example 5

[0043] A high-performance moisturizing film, by weight percentage, comprises the following components: Sodium alginate 1.8%, konjac gum 0.25%, glycerin 0.4%, sodium carboxymethyl cellulose 0.2%, carboxymethyl chitosan 0.15%, sunflower seed oil 0.16%, Tween-20 0.15%, balance water.

[0044] The method for preparing a high-performance moisturizing film includes the following steps: (1) Dissolve and disperse sodium alginate, konjac gum, glycerin, sodium carboxymethyl cellulose and carboxymethyl chitosan in water, then add sunflower seed oil and Tween-20, and ultrasonically disperse evenly to obtain film-forming solution; (2) The film-forming solution was cast into a film, dried in an oven at 40°C for 7 hours, then crosslinked with a 4% calcium chloride solution for 4 minutes, washed and dried again, and equilibrated in a constant temperature and humidity chamber for 48 hours to obtain a high-performance moisturizing film. The tensile strength was tested to be 59.01 MPa; the water vapor transmission coefficient was 1.34 g·mm / (m²). 2 ·d·kPa).

[0045] Example 6

[0046] A high-performance moisturizing film, by weight percentage, comprises the following components: Sodium alginate 1.6%, konjac gum 0.2%, glycerin 0.35%, sodium carboxymethyl cellulose 0.22%, carboxymethyl chitosan 0.12%, sunflower seed oil 0.12%, Tween-20 0.11%, balance water.

[0047] The method for preparing a high-performance moisturizing film includes the following steps: (1) Dissolve and disperse sodium alginate, konjac gum, glycerin, sodium carboxymethyl cellulose and carboxymethyl chitosan in water, then add sunflower seed oil and Tween-20, and ultrasonically disperse evenly to obtain film-forming solution; (2) The film-forming solution was cast into a film, dried in an oven at 40°C for 6 hours, then crosslinked with a 4% calcium chloride solution for 4 minutes, washed and dried again, and equilibrated in a constant temperature and humidity chamber for 48 hours to obtain a high-performance moisturizing film. The tensile strength was tested to be 55.65 MPa; the water vapor transmission coefficient was 1.17 g·mm / (m²). 2 ·d·kPa).

[0048] Example 7

[0049] A high-performance moisturizing film, by weight percentage, comprises the following components: Sodium alginate 1.8%, konjac gum 0.18%, glycerin 0.4%, sodium carboxymethyl cellulose 0.2%, carboxymethyl chitosan 0.15%, sunflower seed oil 0.2%, Tween-20 0.15%, balance water.

[0050] The method for preparing a high-performance moisturizing film includes the following steps: (1) Dissolve and disperse sodium alginate, konjac gum, glycerin, sodium carboxymethyl cellulose and carboxymethyl chitosan in water, then add sunflower seed oil and Tween-20, and ultrasonically disperse evenly to obtain film-forming solution; (2) The film-forming solution was cast into a film, dried in an oven at 40°C for 7 hours, then crosslinked with a 4% calcium chloride solution for 4 minutes, washed and dried again, and equilibrated in a constant temperature and humidity chamber for 48 hours to obtain a high-performance moisturizing film. The tensile strength was tested to be 54.37 MPa; the water vapor transmission coefficient was 1.22 g·mm / (m²). 2 ·d·kPa).

[0051] Example 8

[0052] A high-performance moisturizing film, by weight percentage, comprises the following components: Sodium alginate 1.9%, konjac gum 0.15%, glycerin 0.38%, sodium carboxymethyl cellulose 0.21%, carboxymethyl chitosan 0.11%, sunflower seed oil 0.15%, Tween-20 0.18%, balance water.

[0053] The method for preparing a high-performance moisturizing film includes the following steps: (1) Dissolve and disperse sodium alginate, konjac gum, glycerin, sodium carboxymethyl cellulose and carboxymethyl chitosan in water, then add sunflower seed oil and Tween-20, and ultrasonically disperse evenly to obtain film-forming solution; (2) The film-forming solution was cast into a film, dried in an oven at 43°C for 7 hours, then crosslinked with a 4% calcium chloride solution for 4 minutes. After washing and drying again, the film was equilibrated in a constant temperature and humidity chamber for 48 hours to obtain a high-performance moisturizing film. The tensile strength was tested to be 56.27 MPa, and the water vapor transmission coefficient was 1.18 g·mm / (m). 2 ·d·kPa).

[0054] Example 9

[0055] A high-performance moisturizing film, by weight percentage, comprises the following components: Sodium alginate 1.7%, konjac gum 0.16%, glycerin 0.45%, sodium carboxymethyl cellulose 0.23%, carboxymethyl chitosan 0.14%, sunflower seed oil 0.11%, Tween-20 0.13%, balance water.

[0056] The method for preparing a high-performance moisturizing film includes the following steps: (1) Dissolve and disperse sodium alginate, konjac gum, glycerin, sodium carboxymethyl cellulose and carboxymethyl chitosan in water, then add sunflower seed oil and Tween-20, and ultrasonically disperse evenly to obtain film-forming solution; (2) The film-forming solution was cast into a film, dried in an oven at 45°C for 6 hours, then crosslinked with a 4% calcium chloride solution for 4 minutes, washed and dried again, and equilibrated in a constant temperature and humidity chamber for 48 hours to obtain a high-performance moisturizing film. The tensile strength was tested to be 58.68 MPa; the water vapor transmission coefficient was 1.30 g·mm / (m²). 2 ·d·kPa).

[0057] Example 10

[0058] A high-performance moisturizing film, by weight percentage, comprises the following components: Sodium alginate 1.8%, konjac gum 0.18%, glycerin 0.4%, sodium carboxymethyl cellulose 0.2%, carboxymethyl chitosan 0.15%, sunflower seed oil 0.16%, Tween-20 0.15%, balance water.

[0059] The method for preparing a high-performance moisturizing film includes the following steps: (1) Dissolve and disperse sodium alginate, konjac gum, glycerin, sodium carboxymethyl cellulose and carboxymethyl chitosan in water, then add sunflower seed oil and Tween-20, and ultrasonically disperse evenly to obtain film-forming solution; (2) The film-forming solution was cast into a film, dried in an oven at 40°C for 7 hours, then crosslinked with a 4% calcium chloride solution for 4 minutes, washed and dried again, and equilibrated in a constant temperature and humidity chamber for 48 hours to obtain a high-performance moisturizing film. The tensile strength was tested to be 59.16 MPa; the water vapor transmission coefficient was 1.21 g·mm / (m²). 2 ·d·kPa).

[0060] Comparative Example 1 A high-performance moisturizing film, by weight percentage, comprises the following components: Sodium alginate 1.8%, konjac gum 0.18%, glycerin 0.4%, sodium carboxymethyl cellulose 0%, carboxymethyl chitosan 0.35%, sunflower seed oil 0.16%, Tween-20 0.15%, balance water.

[0061] The method for preparing a high-performance moisturizing film includes the following steps: (1) Sodium alginate, konjac gum, glycerin and carboxymethyl chitosan were dissolved and dispersed in water, and then sunflower seed oil and Tween-20 were added. The mixture was ultrasonically dispersed to obtain a film-forming solution. (2) The film-forming solution was cast into a film, dried in an oven at 40°C for 7 hours, then crosslinked with a 4% calcium chloride solution for 4 minutes, washed and dried again, and equilibrated in a constant temperature and humidity chamber for 48 hours to obtain a high-performance moisturizing film. The tensile strength was tested to be 50.47 MPa; the water vapor transmission coefficient was 1.39 g·mm / (m²). 2 ·d·kPa).

[0062] Comparative Example 2 A high-performance moisturizing film, by weight percentage, comprises the following components: Sodium alginate 1.8%, konjac gum 0.18%, glycerin 0.4%, sodium carboxymethyl cellulose 0.35%, carboxymethyl chitosan 0%, sunflower seed oil 0.16%, Tween-20 0.15%, balance water.

[0063] The method for preparing a high-performance moisturizing film includes the following steps: (1) Dissolve and disperse sodium alginate, konjac gum, glycerin and sodium carboxymethyl cellulose in water, then add sunflower seed oil and Tween-20, and ultrasonically disperse evenly to obtain film-forming solution; (2) The film-forming solution was cast into a film, dried in an oven at 40°C for 7 hours, then crosslinked with a 4% calcium chloride solution for 4 minutes, washed and dried again, and equilibrated in a constant temperature and humidity chamber for 48 hours to obtain a high-performance moisturizing film. The tensile strength was tested to be 52.35 MPa; the water vapor transmission coefficient was 1.44 g·mm / (m²). 2 ·d·kPa).

[0064] Comparative Example 3 A high-performance moisturizing film, by weight percentage, comprises the following components: Sodium alginate 1.8%, konjac gum 0%, glycerin 0.4%, sodium carboxymethyl cellulose 0.2%, carboxymethyl chitosan 0.15%, sunflower seed oil 0.16%, Tween-20 0.15%, balance water.

[0065] The method for preparing a high-performance moisturizing film includes the following steps: (1) Dissolve and disperse sodium alginate, glycerol, sodium carboxymethyl cellulose and carboxymethyl chitosan in water, then add sunflower seed oil and Tween-20, and ultrasonically disperse evenly to obtain film-forming solution; (2) The film-forming solution was cast into a film, dried in an oven at 40°C for 7 hours, then crosslinked with a 4% calcium chloride solution for 4 minutes, washed and dried again, and equilibrated in a constant temperature and humidity chamber for 48 hours to obtain a high-performance moisturizing film. The tensile strength was tested to be 53.62 MPa; the water vapor transmission coefficient was 1.48 g·mm / (m²). 2 ·d·kPa).

[0066] Comparative Example 4 A high-performance moisturizing film, by weight percentage, comprises the following components: Sodium alginate 1.8%, konjac gum 0.18%, glycerin 0.4%, sodium carboxymethyl cellulose 0.2%, carboxymethyl chitosan 0.4%, sunflower seed oil 0.16%, Tween-20 0.15%, balance water.

[0067] The method for preparing a high-performance moisturizing film includes the following steps: (1) Dissolve and disperse sodium alginate, konjac gum, glycerin, sodium carboxymethyl cellulose and carboxymethyl chitosan in water, then add sunflower seed oil and Tween-20, and ultrasonically disperse evenly to obtain film-forming solution; (2) The film-forming solution was cast into a film, dried in an oven at 40°C for 7 hours, then crosslinked with a 4% calcium chloride solution for 4 minutes, washed and dried again, and equilibrated in a constant temperature and humidity chamber for 48 hours to obtain a high-performance moisturizing film. The tensile strength was tested to be 57.14 MPa; the water vapor transmission coefficient was 1.42 g·mm / (m²). 2 ·d·kPa).

[0068] As can be seen from the above embodiments and comparative examples, the present invention effectively reduces the water vapor permeability of the film and significantly improves its moisturizing performance by adding sunflower seed oil. Sunflower seed oil, as a hydrophobic substance, is uniformly dispersed in the alginate network structure under the action of emulsifiers, forming tiny hydrophobic oil droplets that physically block the penetration and migration channels of water molecules, thereby reducing the water vapor permeability of the film and increasing its moisturizing rate. The combination of sodium carboxymethyl cellulose and carboxymethyl chitosan, along with the network-reinforcing effect of konjac gum, effectively compensates for the decrease in mechanical properties caused by the addition of sunflower seed oil. These three substances, together with alginate, synergistically construct a dense and stable three-dimensional network structure through multiple non-covalent bonds, effectively counteracting the weakening effect of sunflower seed oil on the inter-chain forces of the polymer. Simultaneously, the simultaneous addition of sodium carboxymethyl cellulose and carboxymethyl chitosan in this invention constructs a hydrophilic-water-retaining-water-locking triple moisturizing network within the alginate network, producing a synergistic moisturizing effect.

[0069] Specifically, compared to Example 10, Comparative Examples 1 and 2 lacked sodium carboxymethyl cellulose and carboxymethyl chitosan, respectively, resulting in varying degrees of reduction in tensile strength and water vapor barrier properties. This indicates that although both sodium carboxymethyl cellulose and carboxymethyl chitosan are polysaccharides derived from alginate, their molecular structures and functions differ significantly. Sodium carboxymethyl cellulose and alginate are both anionic polysaccharides. The sodium carboxymethyl cellulose molecular chains can embed into the alginate network, filling gaps between molecular chains, increasing the density of physical cross-linking points, and providing skeletal support. Carboxymethyl chitosan, a carboxymethylated derivative of chitosan, can form electrostatic attraction with alginate. This electrostatic interaction is stronger than simple hydrogen bonding, allowing for a stronger bond between carboxymethyl chitosan and alginate. Furthermore, the simultaneous addition of sodium carboxymethyl cellulose and carboxymethyl chitosan enhances the moisturizing effect. The sodium carboxymethyl cellulose molecular chain contains a large number of carboxymethyl and hydroxyl groups, exhibiting good hydrophilicity and water retention capacity. The two work together to create a triple moisturizing network of hydrophilicity, water retention, and water locking within the alginate network.

[0070] Compared to Example 10, Comparative Example 3 did not add konjac gum. Although the mechanical properties did not change significantly, the water vapor permeability coefficient increased significantly, and the moisturizing performance decreased. This is because the long-chain molecular structure of konjac gum can simultaneously form hydrogen bonds with multiple alginate molecular chains, connecting different segments in the alginate network and increasing the overall cohesive energy and toughness of the network. At the same time, an appropriate amount of konjac gum can avoid the problem of uneven component dispersion caused by excessive dosage, and can also reduce the movement rate of sunflower seed oil droplets, assisting the emulsifier in stabilizing the oil-water system and reducing the migration and aggregation of oil droplets during the drying process, thereby helping sunflower seed oil improve its moisturizing ability. It is worth noting that, as can be seen from Comparative Example 4, as a hydrophilic substance, the amount of carboxymethyl chitosan should not be excessive. Otherwise, it will not only break the dense network structure formed by components such as sodium alginate and konjac gum, leading to a looser membrane structure and reduced barrier properties; moreover, its own hydrophilic groups will become a transfer station for water molecule adsorption and transfer, providing more channels for water vapor to permeate the membrane, resulting in a decrease in the moisturizing performance of the membrane.

[0071] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0072] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A high-performance moisturizing film, characterized in that, The raw materials contain the following components by mass percentage: Alginate 1.5-2%, konjac gum 0.1-0.25%, plasticizer 0.3-0.5%, sodium carboxymethyl cellulose 0.15-0.25%, carboxymethyl chitosan 0.1-0.2%, sunflower seed oil 0.1-0.2%, emulsifier 0.1-0.2%, balance water.

2. The high-performance moisturizing film as described in claim 1, characterized in that, The alginate is one or more of sodium alginate and potassium alginate.

3. The high-performance moisturizing film as described in claim 1, characterized in that, The plasticizer is one or more of glycerol, sorbitol, oleic acid, and stearic acid.

4. The high-performance moisturizing film as described in claim 1, characterized in that, The emulsifier is one or more of Tween-20 and Tween-80.

5. The method for preparing a high-performance moisturizing film as described in claim 1, characterized in that, Includes the following steps: (1) Dissolve and disperse alginate, konjac gum, plasticizer, sodium carboxymethyl cellulose and carboxymethyl chitosan in water, then add sunflower seed oil and emulsifier, disperse evenly to obtain film-forming solution; (2) The film-forming liquid is cast into a film, and after drying, cross-linking and equilibration, a high-performance moisturizing film is obtained.

6. The method for preparing a high-performance moisturizing film as described in claim 5, characterized in that, The uniform dispersion is achieved by using an ultrasonic process.

7. The method for preparing a high-performance moisturizing film as described in claim 5, characterized in that, The drying process is carried out in an oven.

8. The method for preparing a high-performance moisturizing film as described in claim 5, characterized in that, The drying temperature is 35-45℃.

9. The method for preparing a high-performance moisturizing film as described in claim 5, characterized in that, The cross-linking is performed using a calcium chloride solution.

10. The method for preparing a high-performance moisturizing film as described in claim 5, characterized in that, The equilibration process involves placing the membrane in a constant temperature and humidity chamber for equilibration.