Cosmetic packaging shell based on degradable environmentally friendly material and method for preparing same

Abstract

The present application relates to the technical field of packaging shell preparation, and discloses a cosmetic packaging shell based on degradable environment-friendly materials and a preparation method thereof.The packaging shell is prepared by blending functional main bodies, polybutylene adipate terephthalate, polylactic acid and other components.The core lies in preparing a functional main body with a crosslinked network structure: a composite polyester monomer containing furan rings, piperazine rings and benzene rings, and modified titanium dioxide with surface grafted succinic anhydride are prepared by chemical bond anchoring reaction.The functional main body builds a stable support skeleton in the material, significantly improving the mechanical strength and impact resistance of the packaging shell;at the same time, the synergistic degradation group and the uniformly dispersed modified titanium dioxide endow the material with excellent degradability and ultraviolet aging resistance, finally realizing the unity of high strength, high stability and high efficiency degradation, meeting the comprehensive needs of cosmetic packaging.

Description

Technical Field

[0001] This invention relates to the field of packaging shell preparation technology, and in particular to cosmetic packaging shells based on biodegradable and environmentally friendly materials and their preparation methods. Background Technology

[0002] The cosmetics packaging industry has long faced the dilemma of balancing environmental protection and performance. Traditional petroleum-based packaging materials not only consume large amounts of non-renewable resources, but are also difficult to degrade naturally after disposal, easily causing persistent environmental pollution, and posing potential health risks from the migration of harmful substances.

[0003] To address this challenge, the industry is actively shifting towards biodegradable materials. Mainstream solutions include the use of bio-based polymers, such as polylactic acid (PLA) made from corn starch, and polybutylene adipate terephthalate (PBAT), which offers flexibility. In addition, composite materials made from natural starch derivatives and plant fibers such as bamboo fiber and bagasse are also attracting attention, with some companies simplifying the recycling process through single-material designs.

[0004] However, existing biodegradable materials still have significant shortcomings. Most materials exhibit poor mechanical properties, struggling to balance high strength and high toughness, making them prone to damage during transportation and use. More importantly, the degradation of many materials depends on specific industrial composting conditions; for example, polylactic acid decomposes inefficiently in natural environments, significantly diminishing its environmental value. Simultaneously, starch-based materials are extremely sensitive to humidity, easily affecting the stability of packaging structures. The compatibility of materials with complex cosmetic formulations, high processing costs, and complex processes collectively restrict their large-scale commercial application. Therefore, the market urgently needs an innovative technological solution that comprehensively balances environmental friendliness, performance, and economy. Thus, developing a biodegradable packaging material that combines excellent mechanical properties, stable performance, and efficient degradation is a pressing technical challenge that needs to be addressed. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a cosmetic packaging shell based on biodegradable and environmentally friendly materials and its preparation method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: Cosmetic packaging shells based on biodegradable and environmentally friendly materials, wherein the cosmetic packaging shells are made of biodegradable and environmentally friendly materials comprising the following components in parts by weight: 20-35 parts of functional main body, 40-55 parts of polybutylene adipate terephthalate, 10-20 parts of polylactic acid, 2-5 parts of compatibilizer, 3-8 parts of plasticizer, 0.2-0.5 parts of antioxidant, and 0.3-0.8 parts of lubricant; The compatibilizer is maleic anhydride-grafted PLA or maleic anhydride-grafted PBAT; the plasticizer is at least one of acetylated tributyl citrate, dioctyl sebacate, and epoxidized soybean oil; the antioxidant is antioxidant 1010 and antioxidant 168 compounded in a mass ratio of 1:1; the lubricant is magnesium stearate or PEG-4000.

[0007] Preferably, the method for preparing the functional subject includes the following steps: H1: Vacuum dry the polyester monomer at 85-90℃ for 8-12 hours, and vacuum dry the modified titanium dioxide at 100-105℃ for 6-8 hours, for later use. H2: Add polyester monomer to the reactor, along with tetrabutyl titanate at 0.02-0.08% of the total mass of polyester monomer and modified titanium dioxide. After nitrogen purging 3-4 times, start stirring and heat to 120-140℃. Then add modified titanium dioxide and ultrasonically disperse for 20-30 minutes to form a homogeneous suspension. Raise the temperature to 160-180℃ and react for 1-1.5 hours. Subsequently, adjust the vacuum level sequentially to 1000-1500Pa, 500-800Pa, and 200-400Pa, and raise the temperature to 180- The reaction was carried out at 200℃ for 2-4 hours. After the reaction was completed, the heating was stopped, the system was cooled to 100-120℃, and the atmospheric pressure was restored. The molten product was extruded into a mold and kept at 80-90℃ for 2-3 hours. Then it was cooled to room temperature, pulverized to a particle size of 2-5 mm, and anhydrous acetone was added at a mass-volume ratio of 1 g:(10-15) mL. The mixture was refluxed and washed 1-2 times at 60-70℃, centrifuged at 3000-4000 rpm for 10-15 min, and finally vacuum dried at 75-85℃ for 10-14 hours to obtain the functional matrix.

[0008] Preferably, the mass ratio of the polyester monomer to the modified titanium dioxide is 1:(0.05-0.2).

[0009] Through the above technical solution, the hydroxyl groups at the end of the polyester monomer structure and the succinic anhydride groups in the modified titanium dioxide structure undergo transesterification and polycondensation reactions under the catalysis of tetrabutyl titanate. This chemically anchors the modified titanium dioxide into the polyester matrix, ultimately preparing a cross-linked network structure functional host. The reaction route is as follows: Preferably, the method for preparing the polyester monomer includes the following steps: A1: 1,4-bis(2-hydroxyethyl)piperazine, dimethyl 2,5-furandicarboxylate and bis(2-hydroxyethyl) terephthalate were vacuum dried at 100-105℃, 80-85℃ and 85-90℃ for 12-24 hours, respectively, and then set aside for later use. A2: Add dried dimethyl 2,5-furandicarboxylate and bis(2-hydroxyethyl) terephthalate to the reactor, then add tetrabutyl titanate. Perform nitrogen purging 3-5 times, start stirring, and slowly heat to 150-170℃, maintaining the temperature for 2-3 hours. Then raise the temperature to 200-210℃, reduce the system pressure from atmospheric pressure to 1200-2000 Pa, maintain for 8-15 minutes, then reduce to 800-1200 Pa, maintain for 8-15 minutes, then reduce to 400-600 Pa, maintain for 8-15 minutes, and react for 0.5-1.5 hours. Reduce the temperature to 170-190℃, and add dried dimethyl 2,4-furandicarboxylate. 2-Hydroxyethyl)piperazine was stirred at 280-350 rpm for 1-2 hours, and the temperature was simultaneously increased to 180-200℃. The stirring speed was adjusted to 320-400 rpm, the vacuum was 200-500 Pa, and the reaction was carried out for 1.5-3 hours. After the reaction was completed, the heating was stopped, the temperature was lowered to below 80-100℃, and the atmospheric pressure was restored. The product was extruded into a mold, cooled to solid at room temperature, and pulverized to a particle size of 1-5 mm. Anhydrous methanol was added at a mass-volume ratio of 1 g:(8-12) mL. The product was refluxed and washed 2-4 times at 50-70℃. After centrifugation and dehydration, the product was vacuum dried at 70-90℃ for 10-16 hours to obtain the polyester monomer.

[0010] Preferably, the mass of the tetrabutyl titanate is 0.03-0.1% of the total mass of 1,4-bis(2-hydroxyethyl)piperazine, dimethyl 2,5-furandicarboxylate and bis(2-hydroxyethyl) terephthalate.

[0011] Preferably, the mass ratio of 1,4-bis(2-hydroxyethyl)piperazine, dimethyl 2,5-furandicarboxylate, and bis(2-hydroxyethyl) terephthalate is 1:(0.85-0.95):(1.08-1.18).

[0012] Using the above technical solution, under the catalysis of tetrabutyl titanate, dimethyl 2,5-furandicarboxylate and bis(2-hydroxyethyl) terephthalate first undergo a transesterification reaction to form an oligomer, which then undergoes transesterification and polycondensation reactions with the hydroxyl groups in the 1,4-bis(2-hydroxyethyl)piperazine structure, ultimately preparing a polyester monomer with double-ended hydroxyl groups containing a "furan-piperazine-benzene" ternary composite main chain structure; the reaction route is as follows: Preferably, the method for preparing the modified titanium dioxide includes the following steps: S1: Take nano titanium dioxide powder, dry it in a vacuum drying oven at 115-120℃ for 10-12 hours, and then transfer it to a dried reactor and seal it for later use; S2: Add anhydrous toluene to the reactor and ultrasonically disperse under nitrogen protection for 30-45 min to form a uniform suspension; add anhydrous acetic acid to the suspension and stir for 10-20 min; then dissolve dihydro-3-[3-(trimethoxysilyl)propyl]furan-2,5-dione in anhydrous toluene and slowly add it dropwise to the suspension; heat the reaction system to 80-110℃ and reflux under nitrogen protection with magnetic stirring for 12-24 h; after the reaction is completed, cool to room temperature and centrifuge the product; wash the product 2-3 times alternately with toluene, anhydrous ethanol, and anhydrous diethyl ether; place the washed solid product in a vacuum drying oven at 50-60℃ and dry for 6-12 h to obtain modified titanium dioxide.

[0013] Preferably, the mass of the dihydro-3-[3-(trimethoxysilyl)propyl]furan-2,5-dione is 5-8% of the mass of the nano-titanium dioxide powder.

[0014] Preferably, the mass of the anhydrous acetic acid is 0.09-0.1% of the mass of dihydro-3-[3-(trimethoxysilyl)propyl]furan-2,5-dione.

[0015] Using the above technical solution, anhydrous acetic acid catalyzes the hydrolysis of dihydro-3-[3-(trimethoxysilyl)propyl]furan-2,5-diketone to generate silanol groups. These silanol groups then undergo a condensation reaction with hydroxyl groups on the surface of nano-titanium dioxide to form chemical bonds, thereby grafting succinic anhydride groups onto the surface of nano-titanium dioxide to obtain modified titanium dioxide. The reaction route is as follows: A preferred method for preparing cosmetic packaging shells based on biodegradable and environmentally friendly materials includes the following steps: Step 1: Vacuum dry the main functional component at 85-90℃ for 8-10 hours, dry polybutylene adipate at 60-70℃ with forced air for 4-6 hours, dry polylactic acid at 70-80℃ under vacuum for 6-8 hours, dry the compatibilizer at 50-60℃ under vacuum for 4-5 hours, dry the antioxidant and lubricant at room temperature for 20-24 hours, and dehydrate the plasticizer using molecular sieves for later use. Step 2: Add polybutylene adipate terephthalate and polylactic acid to a high-speed mixer, turn on the stirrer, and mix at 300-400 rpm for 5-10 minutes. Then add the functional group and compatibilizer, and continue mixing for 8-10 minutes. Next, add the plasticizer, antioxidant and lubricant, increase the speed to 500-600 rpm, and mix for 10-15 minutes to obtain a uniform premixed material. Step 3: Feed the premixed material into a twin-screw extruder. The temperatures of each section of the extruder are as follows: Zone 1: 140-150℃, Zone 2: 155-165℃, Zone 3: 165-175℃, Zone 4: 175-185℃, and the die head: 175-180℃. The screw speed is 180-220 rpm, and the feeding rate is 10-15 kg / h. After the melt is extruded, it is water-cooled at 25-30℃ and pelletized to obtain masterbatch. The masterbatch is vacuum-dried at 60-70℃ for 4-6 hours. The masterbatch is then injection-molded or blow-molded into cosmetic packaging shell preforms. The preforms are annealed at 60-70℃ for 2-3 hours, cooled to room temperature with the box, and the flash is removed. The surface is then cleaned with food-grade anhydrous ethanol and dried with hot air at 50-60℃ to obtain the cosmetic packaging shell.

[0016] Through the aforementioned technical solution, the functional substrate, as the core functional carrier, plays multiple key roles in the material system through its unique cross-linked network structure and component characteristics. Firstly, in terms of mechanical properties, by anchoring the modified titanium dioxide chemical bonds to the polyester matrix, it constructs a stable three-dimensional cross-linked "support skeleton," significantly enhancing the material's tensile strength, rigidity, and impact resistance. This effectively compensates for the strength shortcomings of the polybutylene adipate terephthalate (PAT) / polylactic acid (PLA) blend system, ensuring the packaging shell possesses sufficient load-bearing and breakage resistance. Simultaneously, regarding biodegradability, the functional substrate itself is rich in easily degradable groups such as furan rings and piperazine rings; the introduced modified titanium dioxide further assists in breaking down molecular chains. The synergistic effect of these two factors significantly improves the material's microbial decomposition efficiency in the natural environment, achieving a balance between usability and environmental friendliness. Furthermore, the functional core significantly enhances the material's stability and practicality: modified titanium dioxide imparts excellent UV resistance, synergistically delaying material aging in conjunction with antioxidants, while the dense cross-linked network structure optimizes its barrier properties against moisture and oxygen, better protecting the quality of the contents. In addition, its organic-inorganic composite properties make it a key "bridge" promoting the compatibility of various components, improving the interfacial bonding between polybutylene adipate terephthalate, polylactic acid, and inorganic fillers, preventing component separation or agglomeration, and ensuring the uniformity of processing, plasticization, and the final structure. In summary, through the synergistic effects of these multiple functions, the functional core ultimately achieves a perfect balance between mechanical strength, usage stability, and environmental degradability in cosmetic packaging shells, comprehensively meeting the integrated needs of modern packaging.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention constructs a polyester monomer containing a ternary composite main chain structure of "furan-piperazine-benzene" and chemically bonds it to modified titanium dioxide to form a stable functional matrix. The benzene ring in this structure provides necessary rigidity, the piperazine ring introduces flexibility and degradation sites, and the furan ring synergistically enhances degradability. The synergistic effect of these three components enables the final material to possess high strength and high toughness while also degrading efficiently in the natural environment. Test data shows that the tensile strength and impact strength of the material of this invention are far higher than those of the comparative examples, while the degradation rate reaches nearly 90% in four weeks, successfully solving the core problem of existing biodegradable materials that struggle to balance strength and environmental friendliness.

[0018] 2. The core of this invention lies in anchoring modified titanium dioxide into a polyester matrix through transesterification and polycondensation reactions via chemical bonds, making it a "node" in the cross-linked network rather than a simple physical filler. This "chemical bond anchoring" method, compared with physical mixing, greatly improves the compatibility and dispersibility of inorganic fillers, avoids stress defects caused by agglomeration, and thus significantly enhances the mechanical strength, anti-aging properties, and degradation efficiency of the material.

[0019] 3. This invention modifies the surface of nano-titanium dioxide through grafting, transforming it from pure inorganic particles into "organic-inorganic composite particles." This modification is key to performance breakthroughs. Compared to using unmodified titanium dioxide, it not only solves the compatibility problem with organic phases but also allows the succinic anhydride groups on its surface to participate in cross-linking reactions. Simultaneously, the uniformly dispersed titanium dioxide fully utilizes its UV resistance and works synergistically with antioxidants to effectively delay material aging. Its dense cross-linked structure also optimizes its barrier properties against moisture and oxygen.

[0020] 4. The functional component of this invention, as an organic-inorganic composite structure, acts as a "bridge" in the material system, effectively improving the interfacial bonding between polybutylene adipate terephthalate, polylactic acid substrate, and other additives. This avoids component separation or agglomeration, making the premixed material easier to plasticize and mold during processing, ensuring the structural uniformity of the packaged shell after molding, thereby ensuring the stable performance of various material properties and meeting the needs of large-scale industrial production. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with existing known technologies. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] Example 1: I. Preparation of polyester monomers: A1: Weigh 100g of 1,4-bis(2-hydroxyethyl)piperazine, 85g of dimethyl 2,5-furandicarboxylate, and 108g of bis(2-hydroxyethyl)terephthalate according to a mass ratio of 1:0.85:1.08, and vacuum dry them at 100℃, 80℃, and 85℃ for 12h respectively for later use. A2: Add dried dimethyl 2,5-furandicarboxylate and bis(2-hydroxyethyl) terephthalate to the reactor, add 0.0879 g of tetrabutyl titanate, purge with nitrogen three times, start stirring and slowly heat to 150°C, maintain the temperature for 2 h; raise the temperature to 200°C, and successively reduce the system pressure from atmospheric pressure to 1200 Pa, 800 Pa, and 400 Pa, maintaining each pressure for 8 min, react for 0.5 h; lower the temperature to 170°C, add dried 1,4-bis(2-hydroxyethyl) terephthalate... Piperazine was stirred at 280 rpm for 1 hour; the temperature was simultaneously increased to 180°C, the stirring speed was adjusted to 320 rpm, and the vacuum was maintained at 200 Pa for 1.5 hours; heating was stopped, the temperature was lowered to below 80°C, and the pressure was restored to normal. The product was extruded into a mold, cooled to solid state at room temperature, and then pulverized to a particle size of 1 mm; anhydrous methanol was added at a mass-to-volume ratio of 1 g: 8 mL, and the mixture was refluxed and washed twice at 50°C. After centrifugation and dehydration, the product was dried in a vacuum drying oven at 70°C for 10 hours to obtain the polyester monomer.

[0023] II. Preparation of modified titanium dioxide: S1: Take 100g of nano titanium dioxide powder, dry it in a vacuum drying oven at 115℃ for 10h, transfer it to a dried reactor, seal it and set it aside for later use; S2: Add 500 mL of anhydrous toluene to the reactor and ultrasonically disperse under nitrogen protection for 30 min to form a uniform suspension; add 0.045 g of anhydrous acetic acid to the suspension and stir for 10 min; weigh 5 g of dihydro-3-[3-(trimethoxysilyl)propyl]furan-2,5-dione, dissolve it in 100 mL of anhydrous toluene, and slowly add it dropwise to the suspension; heat the reaction system to 80 °C, and reflux under nitrogen protection with magnetic stirring for 12 h; after cooling to room temperature, centrifuge and wash twice with toluene, anhydrous ethanol, and anhydrous diethyl ether alternately by centrifugation; place the solid product in a vacuum drying oven at 50 °C and dry for 6 h to obtain modified titanium dioxide.

[0024] III. Preparation of the functional subject: H1: Take 100g of polyester monomer and vacuum dry it at 85℃ for 8h, and take 5g of modified titanium dioxide and vacuum dry it at 100℃ for 6h, for later use. H2: Polyester monomers were added to a reactor, along with 0.021g of tetrabutyl titanate. After nitrogen purging three times, stirring was started, and the mixture was heated to 120°C. Modified titanium dioxide was added, and the mixture was ultrasonically dispersed for 20 minutes to form a uniform suspension system. The temperature was raised to 160°C and reacted for 1 hour. Subsequently, the vacuum was adjusted sequentially to 1000Pa, 500Pa, and 200Pa, and the temperature was raised to 180°C and reacted for 2 hours. Heating was stopped, and the system was cooled to 100°C and restored to normal pressure. The molten product was extruded into a mold and kept at 80°C for 2 hours. After cooling to room temperature, the product was pulverized to a particle size of 2mm. Anhydrous acetone was added at a mass-to-volume ratio of 1g:10mL, and the mixture was refluxed and washed once at 60°C. The mixture was centrifuged at 3000rpm for 10 minutes and finally vacuum dried at 75°C for 10 hours to obtain the functional matrix.

[0025] IV. Preparation of cosmetic packaging shells: Step 1: Raw material pretreatment: 20g of functional body is vacuum dried at 85℃ for 8h, 40g of polybutylene adipate terephthalate is dried at 60℃ for 4h, 10g of polylactic acid is vacuum dried at 70℃ for 6h, 10g of maleic anhydride-grafted PLA is vacuum dried at 50℃ for 4h, 0.2g of antioxidant 1010 and antioxidant 168 are compounded in a 1:1 mass ratio to form an antioxidant, 0.3g of magnesium stearate is dried at room temperature for 20h, and 3g of tributyl acetyl citrate is dehydrated by molecular sieve and set aside. Step 2: Add polybutylene adipate terephthalate and polylactic acid to a high-speed mixer and stir at 300 rpm for 5 minutes; add the functional matrix and maleic anhydride-grafted PLA and continue mixing for 8 minutes; then add tributyl acetyl citrate, antioxidant 1010 and antioxidant 168 compounded in a 1:1 mass ratio, and magnesium stearate, increase the speed to 500 rpm and mix for 10 minutes to obtain the premixed material; Step 3: The premixed material is fed into a twin-screw extruder. The temperatures of each section of the extruder are as follows: Zone 1 140℃, Zone 2 155℃, Zone 3 165℃, Zone 4 175℃, and Die Head 175℃. The screw speed is 180 rpm, and the feeding rate is 10 kg / h. After the melt is extruded, it is water-cooled at 25℃ and pelletized to obtain masterbatch. The masterbatch is vacuum-dried at 60℃ for 4 hours and then injection-molded into packaging shell blanks. The blanks are annealed at 60℃ for 2 hours, cooled to room temperature with the box, and the flash is removed. The surface is cleaned with food-grade anhydrous ethanol and dried with hot air at 50℃ to obtain the cosmetic packaging shell.

[0026] Example 2: I. Preparation of polyester monomers: A1: Weigh 100g of 1,4-bis(2-hydroxyethyl)piperazine, 90g of dimethyl 2,5-furandicarboxylate, and 113g of bis(2-hydroxyethyl)terephthalate according to a mass ratio of 1:0.9:1.13, and vacuum dry them at 102.5℃, 82.5℃, and 87.5℃ for 18h respectively for later use. A2: Add dried dimethyl 2,5-furandicarboxylate and bis(2-hydroxyethyl) terephthalate to the reactor, add 0.203 g of tetrabutyl titanate, purge with nitrogen four times, start stirring and slowly heat to 160°C, maintain the temperature for 2.5 h; raise the temperature to 205°C, and successively reduce the system pressure from atmospheric pressure to 1600 Pa, 1000 Pa, and 500 Pa, maintaining each pressure for 12 min, react for 1 h; lower the temperature to 180°C, add dried 1,4-bis(2-hydroxyethyl) terephthalate... The stirring speed was increased to 315 rpm, and the reaction was maintained at this temperature for 1.5 h. Simultaneously, the temperature was increased to 190 °C, the stirring speed was adjusted to 360 rpm, and the vacuum degree was maintained at 350 Pa for 2.25 h. Heating was stopped, the temperature was lowered to below 90 °C, and the pressure was restored to normal. The product was extruded into a mold, cooled to solid state at room temperature, and then pulverized to a particle size of 3 mm. Anhydrous methanol was added at a mass-volume ratio of 1 g: 10 mL, and the mixture was refluxed and washed three times at 60 °C. After centrifugation and dehydration, the product was dried in a vacuum drying oven at 80 °C for 13 h to obtain the polyester monomer.

[0027] II. Preparation of modified titanium dioxide: S1: Take 100g of nano titanium dioxide powder, place it in a vacuum drying oven at 117.5℃ and dry it for 11h, then transfer it to a dried reactor and seal it for later use. S2: Add 600 mL of anhydrous toluene to the reactor and ultrasonically disperse under nitrogen protection for 37.5 min to form a uniform suspension; add 0.06175 g of anhydrous acetic acid to the suspension and stir for 15 min; weigh 6.5 g of dihydro-3-[3-(trimethoxysilyl)propyl]furan-2,5-dione, dissolve it in 150 mL of anhydrous toluene, and slowly add it dropwise to the suspension; heat the reaction system to 95 °C, and reflux under nitrogen protection with magnetic stirring for 18 h; after cooling to room temperature, centrifuge and wash twice with toluene, anhydrous ethanol, and anhydrous diethyl ether alternately by centrifugation; place the solid product in a vacuum drying oven at 55 °C and dry for 9 h to obtain modified titanium dioxide.

[0028] III. Preparation of the functional subject: H1: Take 100g of polyester monomer and vacuum dry it at 87.5℃ for 10h, and take 12.5g of modified titanium dioxide and vacuum dry it at 102.5℃ for 7h, for later use; H2: Polyester monomers were added to a reactor, along with 0.05625 g of tetrabutyl titanate. After nitrogen purging three times, stirring was started, and the mixture was heated to 130°C. Modified titanium dioxide was added, and the mixture was ultrasonically dispersed for 25 min to form a uniform suspension system. The temperature was raised to 170°C and reacted for 1.25 h. Subsequently, the vacuum was adjusted sequentially to 1250 Pa, 650 Pa, and 300 Pa, and the temperature was raised to 190°C and reacted for 3 h. Heating was stopped, and the system was cooled to 110°C and restored to normal pressure. The molten product was extruded into a mold and kept at 85°C for 2.5 h. After cooling to room temperature, the product was pulverized to a particle size of 3 mm. Anhydrous acetone was added at a mass-to-volume ratio of 1 g: 13 mL, and the mixture was refluxed and washed once at 65°C. The mixture was centrifuged at 3500 rpm for 12.5 min and finally vacuum dried at 80°C for 12 h to obtain the functional matrix.

[0029] IV. Preparation of cosmetic packaging shells: Step 1: 32g of functional substrate was vacuum dried at 87.5℃ for 9 hours; 42g of polybutylene adipate terephthalate was dried in a forced-air environment at 65℃ for 5 hours; 12g of polylactic acid was vacuum dried at 75℃ for 7 hours; 3g of maleic anhydride-grafted PLA was vacuum dried at 55℃ for 4.5 hours; 0.3g of antioxidant 1010 and antioxidant 168 were compounded in a 1:1 mass ratio to form an antioxidant; 0.4g of magnesium stearate was dried at room temperature for 22 hours; and 4g of tributyl acetyl citrate was dehydrated using a molecular sieve for later use. Step 2: Add polybutylene adipate terephthalate and polylactic acid to a high-speed mixer and stir at 350 rpm for 7.5 min; add the functional matrix and maleic anhydride-grafted PLA and continue mixing for 9 min; then add acetylated tributyl citrate, antioxidant 1010 and antioxidant 168 compounded in a 1:1 mass ratio, and magnesium stearate, increase the speed to 550 rpm and mix for 12.5 min to obtain the premixed material; Step 3: The premixed material is fed into a twin-screw extruder. The temperatures of each section of the extruder are as follows: Zone 1 145℃, Zone 2 160℃, Zone 3 170℃, Zone 4 180℃, and Die Head 177℃. The screw speed is 200 rpm, and the feeding rate is 13 kg / h. After the melt is extruded, it is water-cooled at 27.5℃ and pelletized to obtain masterbatch. The masterbatch is vacuum-dried at 65℃ for 5 hours and blow-molded into packaging shell blanks. The blanks are annealed at 65℃ for 2.5 hours, cooled to room temperature with the box, and after removing the flash, the surface is cleaned with food-grade anhydrous ethanol and dried with hot air at 55℃ to obtain the cosmetic packaging shell.

[0030] Example 3: I. Preparation of polyester monomers: A1: Weigh 100g of 1,4-bis(2-hydroxyethyl)piperazine, 95g of dimethyl 2,5-furandicarboxylate, and 118g of bis(2-hydroxyethyl)terephthalate according to a mass ratio of 1:0.95:1.18, and vacuum dry them at 105℃, 85℃, and 90℃ for 24h respectively for later use. A2: Add dried dimethyl 2,5-furandicarboxylate and bis(2-hydroxyethyl) terephthalate to the reactor, add 0.313 g of tetrabutyl titanate, purge with nitrogen 5 times, start stirring and slowly heat to 170°C, maintain the temperature for 3 h; raise the temperature to 210°C, and successively reduce the system pressure from atmospheric pressure to 2000 Pa, 1200 Pa, and 600 Pa, maintaining each pressure for 15 min, react for 1.5 h; lower the temperature to 190°C, add dried 1,4-bis(2-hydroxyethyl) terephthalate... Piperazine was stirred at 350 rpm for 2 hours; the temperature was simultaneously increased to 200°C, the stirring speed was adjusted to 400 rpm, and the vacuum was maintained at 500 Pa for 3 hours; heating was stopped, the temperature was lowered to below 100°C, and the pressure was restored to normal. The product was extruded into a mold, cooled to solid state at room temperature, and then pulverized to a particle size of 5 mm; anhydrous methanol was added at a mass-volume ratio of 1 g: 12 mL, and the mixture was refluxed and washed 4 times at 70°C. After centrifugation and dehydration, the product was dried in a vacuum drying oven at 90°C for 16 hours to obtain the polyester monomer.

[0031] II. Preparation of modified titanium dioxide: S1: Take 100g of nano titanium dioxide powder, dry it in a vacuum drying oven at 120℃ for 12h, and then transfer it to a dried reactor and seal it for later use. S2: Add 700 mL of anhydrous toluene to the reactor and ultrasonically disperse under nitrogen protection for 45 min to form a uniform suspension; add 0.08 g of anhydrous acetic acid to the suspension and stir for 20 min; weigh 8 g of dihydro-3-[3-(trimethoxysilyl)propyl]furan-2,5-dione, dissolve it in 200 mL of anhydrous toluene, and slowly add it dropwise to the suspension; heat the reaction system to 110 °C, and reflux under nitrogen protection with magnetic stirring for 24 h; after cooling to room temperature, centrifuge and wash three times alternately with toluene, anhydrous ethanol, and anhydrous diethyl ether; place the solid product in a vacuum drying oven at 60 °C and dry for 12 h to obtain modified titanium dioxide.

[0032] III. Preparation of the functional subject: H1: Take 100g of polyester monomer and vacuum dry it at 90℃ for 12h, and take 20g of modified titanium dioxide and vacuum dry it at 105℃ for 8h, for later use. H2: Polyester monomers were added to a reactor, along with 0.048 g of tetrabutyl titanate. After nitrogen purging four times, stirring was started, and the mixture was heated to 140°C. Modified titanium dioxide was added, and the mixture was ultrasonically dispersed for 30 min to form a uniform suspension system. The temperature was raised to 180°C and reacted for 1.5 h. Subsequently, the vacuum was adjusted sequentially to 1500 Pa, 800 Pa, and 400 Pa, and the temperature was raised to 200°C and reacted for 4 h. Heating was stopped, and the system was cooled to 120°C. The pressure was restored to normal, and the molten product was extruded into a mold. The mixture was kept at 90°C for 3 h, cooled to room temperature, and then pulverized to a particle size of 5 mm. Anhydrous acetone was added at a mass-to-volume ratio of 1 g: 15 mL. The mixture was refluxed and washed twice at 70°C, centrifuged at 4000 rpm for 15 min, and finally vacuum dried at 85°C for 14 h to obtain the functional matrix.

[0033] IV. Preparation of cosmetic packaging shells: Step 1: 35g of functional main body is vacuum dried at 90℃ for 10h; 55g of polybutylene adipate terephthalate is dried in a forced-air environment at 70℃ for 6h; 20g of polylactic acid is vacuum dried at 80℃ for 8h; 5g of maleic anhydride-grafted PLA is vacuum dried at 60℃ for 5h; 0.5g of antioxidant 1010 and antioxidant 168 are compounded in a 1:1 mass ratio to form an antioxidant; 0.8g of magnesium stearate is dried at room temperature for 24h; 8g of tributyl acetyl citrate is dehydrated using a molecular sieve and set aside. Step 2: Add polybutylene adipate terephthalate and polylactic acid to a high-speed mixer and stir at 400 rpm for 10 min; add the functional matrix and maleic anhydride-grafted PLA and continue mixing for 10 min; then add tributyl acetyl citrate, antioxidant 1010 and antioxidant 168 compounded in a 1:1 mass ratio, and magnesium stearate, increase the speed to 600 rpm and mix for 15 min to obtain the premixed material; Step 3: The premixed material is fed into a twin-screw extruder. The temperatures of each section of the extruder are as follows: Zone 1 150℃, Zone 2 165℃, Zone 3 175℃, Zone 4 185℃, and Die Head 180℃. The screw speed is 220 rpm, and the feeding rate is 15 kg / h. After the melt is extruded, it is cooled in water at 30℃ and pelletized to obtain masterbatch. The masterbatch is vacuum dried at 70℃ for 6 hours and then injection molded into packaging shell blanks. The blanks are annealed at 70℃ for 3 hours, cooled to room temperature with the box, and the flash is removed. The surface is cleaned with food-grade anhydrous ethanol and dried with hot air at 60℃ to obtain the cosmetic packaging shell.

[0034] Comparative Example 1: Based on Example 2, the difference is that in the preparation of polyester monomers, the drying and feeding steps of 1,4-bis(2-hydroxyethyl)piperazine are omitted. 90g of dimethyl 2,5-furandicarboxylate, 113g of bis(2-hydroxyethyl) terephthalate, and 0.132g of tetrabutyl titanate are used. 90g of dimethyl 2,5-furandicarboxylate and bis(2-hydroxyethyl) terephthalate are reacted directly in proportion, and the rest is the same as in Example 2.

[0035] Comparative Example 2: Based on Example 2, the difference is that the drying and feeding steps of bis(2-hydroxyethyl) terephthalate were omitted in the preparation of the polyester monomer. 90g of dimethyl 2,5-furandicarboxylate, 100g of 1,4-bis(2-hydroxyethyl)piperazine, and 0.124g of tetrabutyl titanate were used. 90g of dimethyl 2,5-furandicarboxylate and 1,4-bis(2-hydroxyethyl)piperazine were reacted directly in proportion, and the rest was the same as in Example 2.

[0036] Comparative Example 3: Based on Example 2, the difference is that 90g of dimethyl 2,5-furandicarboxylate was used to replace the polyester monomer in the reaction with modified titanium dioxide to prepare the functional matrix, and the rest was the same as in Example 2.

[0037] Comparative Example 4: Based on Example 2, the difference is that 113g of bis(2-hydroxyethyl) terephthalate was used to replace the polyester monomer in the reaction with modified titanium dioxide to prepare the functional matrix, and the rest was the same as in Example 2.

[0038] Comparative Example 5: Based on Example 2, the difference is that the functional body preparation steps H1 and H2 are removed. 100g of polyester monomer and 12.5g of modified titanium dioxide are dried and mixed in a high-speed mixer for 10 minutes. Then, polybutylene adipate, polylactic acid and other additives are added. The rest is the same as in Example 2.

[0039] Comparative Example 6: Based on Example 2, the difference is that the modified titanium dioxide preparation step is cancelled, that is, steps S1 and S2 are removed, and 12.5g of unmodified nano titanium dioxide powder is directly taken and vacuum dried at 102.5℃ for 7h. The rest is the same as in Example 2.

[0040] Test Example: The cosmetic packaging shells prepared in Examples 1-3 and Comparative Examples 1-6 were used as samples. Three parallel samples were taken from each group for performance testing, and the average value of the test results was taken. Tensile strength was tested according to standard GB / T 1040.2-2022; impact performance was tested according to standard GB / T 1043.2-2018; and UV aging resistance was tested according to standard GB / T 16422.1-2019: the samples were placed in a UVA-1140 ultraviolet accelerated aging tester for 100 hours (irradiation intensity 0.5W / m², black standard temperature 63℃), and the tensile strength retention rate after aging was tested (strength after aging / initial strength × 100%).

[0041] According to standard GB / T 3682.1-2018, the melt flow rate (MFR, g / 10min) was tested at a temperature of 180℃ and a load of 2.16 kg. The mass of melt flowing out within 10 minutes was recorded. A plot of garden soil was selected, and a pit approximately 5 cm deep was dug. Samples of each group were prepared into 2 mm long specimens and placed in the dug pit. The specimens were then completely covered with soil. One group of specimens was taken out every two weeks, with three specimens in each group, for a total of four groups. The experimental period was four weeks. The specimens were cleaned and vacuum-dried to remove moisture. Their mass was then measured, and the mass loss rate W was calculated according to the formula: W = [(M0-M1) / M] O [×100%; W is the mass loss rate; M0 is the initial mass, g; M1 is the mass of the soil after degradation, g; the test results are as follows:] Table 1. Performance Test Results of Cosmetic Packaging Shells Data Analysis: The cosmetic packaging shells prepared in Examples 1-3 exhibit high tensile strength and good impact resistance, while also demonstrating excellent resistance to UV aging. Their suitable melt flow rate ensures good processability. Furthermore, these packaging shells show high degradation efficiency in natural soil environments, balancing durability with environmentally friendly degradation requirements. Their stable structure and consistent performance enable them to meet the long-term use and environmental protection requirements of cosmetic packaging.

[0042] Compared to Example 2, the performance of Comparative Examples 1 and 2 declined across the board, directly confirming the necessity of the synergistic effect of 1,4-bis(2-hydroxyethyl)piperazine, dimethyl 2,5-furandicarboxylate, and bis(2-hydroxyethyl) terephthalate. The polyester monomer of this invention constructs a ternary composite main chain structure of "furan-piperazine-benzene": the benzene ring provides basic rigidity, ensuring mechanical strength; the piperazine ring introduces flexibility and target sites for microbial degradation; the furan ring, as another degradable group, synergistically enhances the effect with the piperazine ring. The bihydroxyl-terminated polyester monomer generated by the reaction of the three in a specific ratio achieves a delicate balance of rigidity, flexibility, and degradability in its molecular structure. This is a prerequisite for the subsequent formation of a stable and uniform cross-linked network "support skeleton" with modified titanium dioxide through transesterification and polycondensation reactions. The absence of any component in Comparative Example 1 or Comparative Example 2 results in the destruction of the main chain structure, insufficient rigidity, or the loss of flexibility and degradation sites, leading to a decrease in the cross-linking density of the functional components, a loose network, and ultimately, a deterioration in the overall performance of the material.

[0043] Compared to Example 2, Comparative Examples 3 and 4 showed a significant decrease in material properties, particularly in degradation rate, after replacing the polyester monomer with a single ester compound. This highlights the key value of the synergistic design of multi-ring structures in this invention, rather than the stacking of single structures. Single esters, such as dimethyl furanate or terephthalate, can only provide one ring structure, resulting in overly regular molecular chains lacking flexibility and multiple degradation sites. Furthermore, the number and chemical activity of their terminal hydroxyl groups cannot match the succinic anhydride grafting density on the modified titanium dioxide surface, making effective transesterification and polycondensation reactions difficult to occur, and preventing the construction of a three-dimensional cross-linked network throughout the material. Consequently, the material either suffers from insufficient mechanical strength due to containing only furan rings or extremely poor degradation performance due to containing only benzene rings, failing to achieve a balance between rigidity, flexibility, and degradability. This fully demonstrates the core role of the composite polyester monomer designed in this invention in synergistically improving the overall performance of the material.

[0044] Compared to Example 2, Comparative Example 5 omitted the preparation step of the functional matrix and only performed physical mixing, resulting in a decrease in all properties of the material. This reveals the overwhelming advantage of "chemical bond anchoring" over "physical mixing". The key to this invention is that, through tetrabutyl titanate catalysis, the terminal hydroxyl groups of the polyester monomer undergo ester exchange and polycondensation with the succinic anhydride groups on the surface of modified titanium dioxide, thereby transforming the inorganic phase titanium dioxide from a "dispersed phase" into a "crosslinking node", which is firmly anchored in the organic polyester matrix through chemical bonds. This covalent connection not only solves the problem of inorganic filler agglomeration but also strengthens the interfacial bonding force. In contrast, the physical mixing of Comparative Example 5 lacks chemical bonding, has poor interfacial compatibility, and titanium dioxide is prone to agglomeration, forming stress defect points, leading to a decrease in mechanical properties. At the same time, the loose mixed system cannot form an effective barrier and UV resistance synergistic effect, and degradation sites are difficult to expose, ultimately resulting in a double deterioration of anti-aging and degradation performance.

[0045] Compared to Example 2, Comparative Example 6 showed a decline in performance after using unmodified titanium dioxide, highlighting that surface modification of titanium dioxide is the cornerstone for achieving performance breakthroughs. Unmodified titanium dioxide has a highly polar surface, extremely poor compatibility with organic phases, and is prone to agglomeration, becoming a mechanical weakness. The core modification of this invention is the successful grafting of succinic anhydride groups onto the surface of titanium dioxide through hydrolysis and condensation with a silane coupling agent, transforming it from a pure inorganic particle into an "organic-inorganic composite particle." This transformation endows titanium dioxide with dual functions: firstly, the succinic anhydride groups on the surface can react with polyester monomers, becoming "nodes" in the crosslinking network, solving the compatibility and dispersibility problems; secondly, uniformly dispersed titanium dioxide can fully utilize its UV resistance properties and assist in breaking down molecular chains during degradation, accelerating material decomposition. Unmodified titanium dioxide cannot achieve these functions due to agglomeration, highlighting the key innovative significance of graft modification design in comprehensively improving material performance.

[0046] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A cosmetic packaging shell based on biodegradable and environmentally friendly materials, characterized in that, The cosmetic packaging shell is made of a biodegradable and environmentally friendly material containing the following components in parts by weight: 20-35 parts of functional body, 40-55 parts of polybutylene adipate terephthalate, 10-20 parts of polylactic acid, 2-5 parts of compatibilizer, 3-8 parts of plasticizer, 0.2-0.5 parts of antioxidant, and 0.3-0.8 parts of lubricant; The compatibilizer is maleic anhydride-grafted PLA or maleic anhydride-grafted PBAT; the plasticizer is at least one of acetylated tributyl citrate, dioctyl sebacate, and epoxidized soybean oil; the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a 1:1 mass ratio; and the lubricant is magnesium stearate or PEG-4000. The method for preparing the functional subject, Includes the following steps: H1: Vacuum dry the polyester monomer at 85-90℃ for 8-12 hours, and vacuum dry the modified titanium dioxide at 100-105℃ for 6-8 hours, for later use. H2: Add polyester monomer to the reactor, along with tetrabutyl titanate at 0.02-0.08% of the total mass of polyester monomer and modified titanium dioxide. After nitrogen purging 3-4 times, start stirring and heat to 120-140℃. Then add modified titanium dioxide and ultrasonically disperse for 20-30 minutes to form a homogeneous suspension. Raise the temperature to 160-180℃ and react for 1-1.5 hours. Subsequently, adjust the vacuum level sequentially to 1000-1500Pa, 500-800Pa, and 200-400Pa, and raise the temperature to 180- The reaction was carried out at 200℃ for 2-4 hours. After the reaction was completed, the heating was stopped, the system was cooled to 100-120℃, and the atmospheric pressure was restored. The molten product was extruded into a mold and kept at 80-90℃ for 2-3 hours. Then it was cooled to room temperature, pulverized to a particle size of 2-5 mm, and anhydrous acetone was added at a mass-volume ratio of 1 g:(10-15) mL. The mixture was refluxed and washed 1-2 times at 60-70℃, centrifuged at 3000-4000 rpm for 10-15 min, and finally vacuum dried at 75-85℃ for 10-14 hours to obtain the functional matrix. The method for preparing the polyester monomer includes the following steps: A1: 1,4-bis(2-hydroxyethyl)piperazine, dimethyl 2,5-furandicarboxylate and bis(2-hydroxyethyl) terephthalate were vacuum dried at 100-105℃, 80-85℃ and 85-90℃ for 12-24 hours, respectively, and then set aside for later use. A2: Add dried dimethyl 2,5-furandicarboxylate and bis(2-hydroxyethyl) terephthalate to the reactor, then add tetrabutyl titanate. Perform nitrogen purging 3-5 times, start stirring, and slowly heat to 150-170℃, maintaining the temperature for 2-3 hours. Then raise the temperature to 200-210℃, reduce the system pressure from atmospheric pressure to 1200-2000 Pa, maintain for 8-15 minutes, then reduce to 800-1200 Pa, maintain for 8-15 minutes, then reduce to 400-600 Pa, maintain for 8-15 minutes, and react for 0.5-1.5 hours. Reduce the temperature to 170-190℃, and add dried dimethyl 2,4-furandicarboxylate. 2-Hydroxyethyl)piperazine was stirred at 280-350 rpm for 1-2 hours, and the temperature was simultaneously increased to 180-200℃. The stirring speed was adjusted to 320-400 rpm, the vacuum degree was 200-500 Pa, and the reaction was carried out for 1.5-3 hours. After the reaction was completed, the heating was stopped, the temperature was lowered to below 80-100℃, the atmospheric pressure was restored, the product was extruded into a mold, cooled to solid at room temperature, and pulverized to a particle size of 1-5 mm. Anhydrous methanol was added at a mass-volume ratio of 1 g:(8-12) mL, and the mixture was refluxed and washed 2-4 times at 50-70℃. After centrifugation and dehydration, the product was vacuum dried at 70-90℃ for 10-16 hours to obtain the polyester monomer. The method for preparing the modified titanium dioxide includes the following steps: S1: Take nano titanium dioxide powder, dry it in a vacuum drying oven at 115-120℃ for 10-12 hours, and then transfer it to a dried reactor and seal it for later use; S2: Add anhydrous toluene to the reactor and ultrasonically disperse under nitrogen protection for 30-45 min to form a uniform suspension; add anhydrous acetic acid to the suspension and stir for 10-20 min; then dissolve dihydro-3-[3-(trimethoxysilyl)propyl]furan-2,5-dione in anhydrous toluene and slowly add it dropwise to the suspension; heat the reaction system to 80-110℃ and reflux under nitrogen protection with magnetic stirring for 12-24 h; after the reaction is completed, cool to room temperature and centrifuge the product; wash the product 2-3 times alternately with toluene, anhydrous ethanol, and anhydrous diethyl ether; place the washed solid product in a vacuum drying oven at 50-60℃ and dry for 6-12 h to obtain modified titanium dioxide.

2. The cosmetic packaging shell based on biodegradable and environmentally friendly materials according to claim 1, characterized in that, The mass ratio of the polyester monomer to the modified titanium dioxide is 1:(0.05-0.2).

3. The cosmetic packaging shell based on biodegradable and environmentally friendly materials according to claim 1, characterized in that, The mass of the tetrabutyl titanate is 0.03-0.1% of the total mass of 1,4-bis(2-hydroxyethyl)piperazine, dimethyl 2,5-furandicarboxylate, and bis(2-hydroxyethyl) terephthalate.

4. The cosmetic packaging shell based on biodegradable and environmentally friendly materials according to claim 1, characterized in that, The mass ratio of 1,4-bis(2-hydroxyethyl)piperazine, dimethyl 2,5-furandicarboxylate, and bis(2-hydroxyethyl) terephthalate is 1:(0.85-0.95):(1.08-1.18).

5. The cosmetic packaging shell based on biodegradable and environmentally friendly materials according to claim 1, characterized in that, The mass of the dihydro-3-[3-(trimethoxysilyl)propyl]furan-2,5-dione is 5-8% of the mass of the nano-titanium dioxide powder.

6. The cosmetic packaging shell based on biodegradable and environmentally friendly materials according to claim 1, characterized in that, The mass of the anhydrous acetic acid is 0.09-0.1% of the mass of dihydro-3-[3-(trimethoxysilyl)propyl]furan-2,5-dione.

7. The method for preparing a cosmetic packaging shell based on biodegradable and environmentally friendly materials as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Vacuum dry the main functional component at 85-90℃ for 8-10 hours, dry polybutylene adipate at 60-70℃ with forced air for 4-6 hours, dry polylactic acid at 70-80℃ under vacuum for 6-8 hours, dry the compatibilizer at 50-60℃ under vacuum for 4-5 hours, dry the antioxidant and lubricant at room temperature for 20-24 hours, and dehydrate the plasticizer using molecular sieves for later use. Step 2: Add polybutylene adipate terephthalate and polylactic acid to a high-speed mixer, turn on the stirrer, and mix at 300-400 rpm for 5-10 minutes. Then add the functional group and compatibilizer, and continue mixing for 8-10 minutes. Next, add the plasticizer, antioxidant and lubricant, increase the speed to 500-600 rpm, and mix for 10-15 minutes to obtain a uniform premixed material. Step 3: Feed the premixed material into a twin-screw extruder. The temperatures of each section of the extruder are as follows: Zone 1: 140-150℃, Zone 2: 155-165℃, Zone 3: 165-175℃, Zone 4: 175-185℃, and the die head: 175-180℃. The screw speed is 180-220 rpm, and the feeding rate is 10-15 kg / h. After the melt is extruded, it is water-cooled at 25-30℃ and pelletized to obtain masterbatch. The masterbatch is vacuum-dried at 60-70℃ for 4-6 hours. The masterbatch is then injection-molded or blow-molded into cosmetic packaging shell preforms. The preforms are annealed at 60-70℃ for 2-3 hours, cooled to room temperature with the box, and the flash is removed. The surface is then cleaned with food-grade anhydrous ethanol and dried with hot air at 50-60℃ to obtain the cosmetic packaging shell.

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