Preparation method and application of 100% bio-based beeswax coating agent

Abstract

The invention relates to a preparation method and application of a 100% bio-based beeswax coating agent. According to the coating agent, beewax derived from natural plants or animals is used as a main film forming substance, bio-based fatty acid is used as an emulsifier, a simple and efficient one-step emulsification process is adopted, and a stable milky white beewax emulsion can be prepared without using any petrochemical raw materials or harmful additives. The preparation method comprises the following steps: heating and mixing the beeswax, the bio-based fatty acid and the water to uniformly melt, adding neutralizers such as ammonia water, heating until emulsification, cooling and filtering to obtain a target product. Tests show that the product has good film-forming property, oil resistance and water resistance, the raw materials are green and renewable, the process is simple and convenient, the cost is low, and the product is safe and non-toxic. The biodegradable protective film is suitable for application scenes with requirements on biodegradability and protective property in the fields of food, agriculture and biological medicine, and has wide industrialization prospects and popularization value.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer functional materials and green coatings, and specifically relates to a preparation method of a 100% bio-based beeswax film agent and its multifunctional applications. Background Art

[0002] In recent years, with increasing global pressure on resources and the environment, green and sustainable development has become a consensus among the international community and various industries. Against this backdrop, the development of bio-based materials derived from renewable resources to replace traditional functional products that rely on petrochemical resources has become a research hotspot in materials science, chemical engineering, and environmental protection technology. Among these, bio-based coating materials with film-forming properties are attracting widespread attention due to their potential applications in food packaging, agricultural coatings, medical carriers, and daily chemicals.

[0003] Traditional wax-based coatings mostly use petrochemical-derived raw materials such as paraffin wax, microcrystalline wax, and synthetic polymer wax as the primary film-forming agent, and utilize non-ionic or anionic petrochemical emulsifiers for emulsification and dispersion. While these products meet functional requirements to a certain extent, their non-renewable raw materials, poor biodegradability, and high potential toxicity pose a threat to ecological and environmental protection and human health, and have been increasingly subject to both policy and market restrictions.

[0004] Beeswax is a natural lipid material secreted by bees. Its main components are esters, fatty acids and long-chain alcohols. It has excellent hydrophobicity, film-forming properties, biodegradability and biocompatibility, and is widely used in food preservation coatings, pesticide carriers, drug coatings, cosmetics and personal care products. Compared with paraffin wax, beeswax is naturally derived and highly sustainable, and the coating has good moisture-proof, anti-oxidation and sustained-release properties. It is a green material with great development potential. However, most of the beeswax emulsions or film-forming agent products currently on the market still use some petrochemical-derived emulsifiers, additives or plasticizers, making it difficult to achieve a truly fully bio-based system, which seriously restricts its application in scenarios with high requirements for material safety, such as green packaging, medical health, and agricultural environmental protection.

[0005] In addition, beeswax itself has a relatively high melting point and strong hydrophobicity, which makes it relatively difficult to emulsify. Existing emulsification technologies generally have the following problems: Complex preparation process: The traditional emulsification process requires multiple steps, long shearing or high-temperature treatment, high energy consumption, and unstable process; Poor system stability: the emulsion has a wide particle size distribution, is prone to aggregation and stratification, and has a short storage period; High cost and insufficient greenness: Raw material procurement and processing consume high energy and do not meet green manufacturing evaluation indicators.

[0006] Some related patented technologies on the market have explored the improvement of paraffin emulsion system, but still have not broken the framework of petrochemical system as the core raw material: For example, Chinese invention patent CN110964212A discloses a paraffin emulsion, which uses a composition of paraffin, non-ionic emulsifier, isoparaffin, etc., has small particle size and high visual transparency, but the used emulsifier is not water-resistant, has high content, the overall water resistance and emulsion stability are poor, and almost all raw materials are derived from petrochemical products, and the bio-based content is extremely low; For another example, the paraffin emulsion composition disclosed in CN117264429 uses paraffin, ethylene-vinyl acetate copolymer wax and water-soluble polymer, etc., which has improved stability, but still belongs to the petrochemical path and does not have the properties of biodegradation or sustainability.

[0007] Therefore, there is still a lack of a 100% bio-based beeswax coating agent which is truly based on natural beeswax as the film-forming base and all auxiliary ingredients are derived from renewable resources, and a preparation method thereof. Meanwhile, the material also needs to have comprehensive advantages in process simplification, emulsion stability improvement, and terminal application safety and functionality, to meet the multiple needs of modern material industry for green low-carbon, functional refinement and broad-spectrum application. SUMMARY

[0008] (I) Technical problems solved The present application aims to develop a preparation method of beeswax coating agent based on 100% bio-based raw materials, using beeswax as the main film-forming material, combining with natural fatty acid emulsifier, and adopting a simple one-step emulsification process to prepare a beeswax emulsion system with good stability. The product is completely derived from renewable biological resources, meets the requirements of the national strategy of green and low-carbon development, and has good physical stability and wide application adaptability.

[0009] The technical solution of the present application is as follows: A preparation method of beeswax coating agent based on 100% bio-based raw materials, comprising the following steps: 1. Raw material pretreatment and premixing: mix fatty acid (such as myristic acid extracted from vegetable oil), beeswax and water, heat to 70-80℃ in a reaction kettle, continuously stir until the beeswax is completely melted, and fully mix with the emulsifier and water.

[0010] 2. Emulsification reaction: slowly add ammonia or other optional neutralizing agent to neutralize the fatty acid and adjust the pH in the above mixture, and continue to heat to 90-100℃, and the emulsification reaction is carried out in this temperature range to form a stable white beeswax emulsion.

[0011] 3. Dilution and cooling: Add appropriate amount of hot water to the emulsion for dilution, then quickly cool it to room temperature (about 30-40°C), filter and remove impurities to obtain a milky white and stable 100% bio-based beeswax film agent product.

[0012] (2) Beneficial effects 1. All raw materials are derived from natural animal and plant extracts, avoiding the use of any synthetic emulsifiers or additives from petrochemical sources, and fully realizing a 100% bio-based formula.

[0013] 2. The one-step emulsification process adopted is simple and efficient, avoiding the high energy consumption and complex equipment problems in the traditional multi-step emulsification process, and is conducive to industrial scale-up and large-scale production.

[0014] 3. The obtained product is a stable, non-toxic, environmentally friendly white beeswax emulsion with good coating properties and biocompatibility, and can be widely used in food and agriculture-related products.

[0015] 4. The film layer after film formation has strong moisture and oil resistance, which improves the functionality of the packaging substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a preparation flow chart of the present invention; Figure 2 The cobb values ​​of Example 1, Example 2 and Comparative Example 1 of the present invention are compared. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] The present invention provides a technical solution, such as Figure 1-2 As shown, a preparation method and application of a 100% bio-based beeswax film agent includes the following steps: 1. Raw material pretreatment and premixing: Mix fatty acids (such as myristic acid extracted from animal and plant oils), beeswax and water, place them in a reactor and heat to 70-80°C, continue stirring until the beeswax is completely melted, and then fully mix with the emulsifier and water.

[0019] 2. Emulsification reaction: Slowly add ammonia water or other optional neutralizing agent to the above mixed system to neutralize the fatty acid and adjust the pH, and continue heating to 90-100°C. The emulsification reaction proceeds within this temperature range to form a stable white beeswax emulsion.

[0020] 3. Dilution and cooling: Add appropriate amount of hot water to the emulsion for dilution, then quickly cool it to room temperature (about 30-40°C), filter and remove impurities to obtain a milky white and stable 100% bio-based beeswax film agent product.

[0021] Example 1 The preparation method of the myristic acid emulsified beeswax film agent includes adding 7.2 grams of myristic acid, 70 grams of water, and 48 grams of beeswax (melting point 60-65°C) to a sealed reaction vessel, heating and stirring to 70-80°C, and thoroughly mixing until the beeswax is completely melted. Subsequently, a mixture consisting of 3.6 grams of 25% concentrated ammonia and 10 grams of water is added, and the mixture is heated to 90-100°C and held for 30 minutes to emulsify the beeswax and form a stable emulsion. The mixture is then diluted with 28.5 grams of hot water, rapidly cooled to 30-40°C, and filtered to obtain a uniform, stable white beeswax emulsion with a solids content of 33.0%.

[0022] Example 2 Preparation method for stearic acid emulsified beeswax film: Add 7.2 grams of stearic acid, 70 grams of water, and 48 grams of beeswax to a sealed container, heat and stir to 70-80°C, and completely melt the beeswax. Then, add a mixture of 3.5 grams of 25% concentrated ammonia and 10 grams of water, continue heating to 90-100°C, and maintain the temperature for 30 minutes until a stable white emulsion forms. Then, add 28.6 grams of hot water, cool to 30-40°C, and filter to obtain a uniform beeswax emulsion with a solids content of 33.0%.

[0023] Comparative Example 1 Preparation method for a stearic acid emulsified paraffin film: 7.2 grams of stearic acid, 70 grams of water, and 48 grams of paraffin wax (melting point approximately 58°C) are added to a sealed container and heated with stirring to 70-80°C. After the paraffin wax is completely melted and mixed, a mixture of 2.2 grams of 25% concentrated aqueous ammonia and 10 grams of water is added. The mixture is heated to 90-100°C and held for 30 minutes to emulsify into a white emulsion. The mixture is diluted with 30 grams of hot water, cooled to 30-40°C, and filtered to obtain a paraffin wax emulsion. However, this sample exhibited significant wax floating during storage, and its stability was inferior to that of the example. The solids content of the product was also 33.0%.

[0024] Performance Testing The emulsions obtained in Example 1, Example 2 and Comparative Example 1 were coated on the surface of untreated white cardboard and dried at 80° C. The coating amount was 6 g / m 2 . The following performance evaluations were performed on the obtained coatings: a. Oil resistance test (Kit Test, according to TAPPI T559) Different coating samples were tested for their oil resistance levels according to the standard. The test results are as follows (level 12 is the best and level 1 is the worst):

[0025] The data in the table above demonstrate that the coatings produced in Examples 1 and 2 of the present invention, as well as Comparative Example 1, all exhibited considerable oil-repellency, demonstrating that each sample group formed a continuous, uniform, and dense film on the substrate surface, demonstrating a moderate oil-permeation barrier. This property is crucial for applications sensitive to oil permeation, such as food packaging and pharmaceutical coatings.

[0026] It is worth noting that the formulas used in Example 1 and Example 2 are completely based on 100% bio-based raw materials, including natural fatty acids and animal-derived beeswax, and do not contain any petrochemical-based emulsifiers or additives. They still achieve oil-proof performance equivalent to or even better than that of the paraffin-based film agent (Comparative Example 1), indicating that the present invention achieves a good balance between environmental protection and performance, and has significant practical value and promotion prospects.

[0027] b. Water resistance test The coating agents prepared in Example 1, Example 2, and Comparative Example 1 were uniformly applied to white cardboard and dried to form coating samples. During testing, two drops of purified water were added to each coating sample using a dropper. After standing for three minutes, the surface water droplets were gently blotted with a dry napkin. The coatings were then observed for signs of whitening, stickiness, blistering, or structural damage.

[0028]

[0029] The test results above demonstrate that the coatings prepared in Examples 1 and 2 exhibit excellent water resistance after forming films on paper surfaces. The coatings exhibited no noticeable whitening, swelling, or structural damage after being exposed to water droplets. The water droplets maintained a spherical shape and rolled freely on the coating surface, demonstrating the coatings' excellent hydrophobicity and resistance to water penetration.

[0030] Then, according to GB / T 1540-2002, Determination of water absorption of paper and paperboard (Cobb method), the Cobb value of 1 square meter of coated paperboard was tested for 180s. Figure 1 The results show that the cobb values ​​of 100% bio-based film-forming agent Example 1, Example 2 and Comparative Example 1 (partially bio-based) are very close, further indicating that the 100% bio-based film-forming agent also has excellent water resistance.

[0031] This excellent water resistance not only verifies that the coating agent of the present invention has a stable physical structure and density after film formation, but also further confirms its ability to block and regulate moisture in practical applications. It is particularly suitable for fruit and vegetable preservation scenarios that require moderate moisture exchange, agricultural seed treatment that requires sustained release and coating effects, and biopharmaceutical carrier systems with high requirements for material biocompatibility and stability.

[0032] Therefore, the 100% bio-based beeswax film agent provided by the present invention not only maintains good ecological and environmental protection properties, but also has film-forming stability, oil resistance and water resistance, and has broad application prospects and promotion value. It is particularly suitable for the fields of fruit and vegetable water retention and freshness preservation, seed coating treatment and biopharmaceutical materials, meeting the industry needs of green and sustainable development.

[0033] This beeswax coating agent is suitable for surface preservation, waterproofing and anti-corrosion treatment of fruits and vegetables. It can also be used in crop seed coating, pharmaceutical product coating, leather care, cosmetics and other fields.

[0034] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A 100% bio-based beeswax film agent, characterized in that: The coating agent includes the following components in percentage by weight: Beeswax: 10% to 50%; Bio-based fatty acids: 5% to 40%, wherein the fatty acids are selected from one or more of myristic acid, stearic acid, palmitic acid, etc.; Neutralizer: 0.5% to 5%, the neutralizer is one or more of ammonia, sodium hydroxide, potassium hydroxide or other organic amines Deionized water: 35% to 80%; The beeswax is unmodified beeswax of natural origin, the film-forming agent does not contain any petroleum-based raw materials, and the prepared emulsion is milky white and has good stability, film-forming properties, water resistance and oil resistance.

2. The beeswax film-forming agent according to claim 1, wherein the melting point of the beeswax is 60-65°C.

3. The beeswax film according to claim 1, wherein the bio-based fatty acid and the neutralizer react in situ to form an emulsifier during the preparation process.

4. beeswax film agent according to claim 1, wherein the neutralizing agent is 1-30% concentration of ammonia water. The beeswax film-forming agent according to claim 1 , wherein the solid content of the obtained emulsion is 10% to 50%.

6. A method for preparing the beeswax film according to claim 1, characterized in that: The following steps are involved: (1) Mix beeswax, bio-based fatty acids and deionized water, heat to 70-80°C, and stir until the beeswax is melted and mixed evenly; (2) Add ammonia or other bio-based neutralizer, continue heating to 90-100°C, and form a stable emulsion under stirring conditions; (3) Add hot water to the emulsion for dilution, quickly cool it to 30-40° C., and then filter it to obtain the milky white beeswax film agent.

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