Alcohol-resistant cosmetic packaging shell material based on polylactic acid modification and preparation method thereof

Abstract

The invention discloses an alcohol-resistant cosmetic packaging shell material based on polylactic acid modification and a preparation method thereof, and belongs to the technical field of packaging material preparation. The polylactic acid modified alcohol-resistant cosmetic packaging shell material is used for solving the technical problem that in the prior art, the alcohol resistance and the mechanical property of a cosmetic packaging shell material need to be further improved. Comprising the following components in parts by weight: 65-85 parts of alcohol-resistant modified polylactic acid, 10-15 parts of polylactic acid modified sepiolite, 3-5 parts of a fluorosilicone epoxy compatilizer and 1-3 parts of an auxiliary material. Polylactic acid is used as a matrix, ring opening polymerization is initiated through 2-chloro-N-(2-hydroxyethyl)-acetamide, polyether amine is grafted, alcohol-resistant modified polylactic acid is prepared, sepiolite is acidified and grafted with polylactic acid to improve interfacial compatibility, a fluorosilicone epoxy compatilizer is prepared for synergistic modification, all the components are premixed and subjected to twin-screw melt extrusion, and the composite material is prepared. The cosmetic packaging shell material with alcohol resistance and mechanical property is prepared.

Description

Technical Field

[0001] This invention relates to the field of packaging material preparation technology, specifically to an alcohol-resistant cosmetic packaging shell material based on polylactic acid modification and its preparation method. Background Technology

[0002] In recent years, the proportion of alcohol solvents such as ethanol and isopropanol in cosmetic formulations has been increasing, placing comprehensive demands on packaging materials for long-term alcohol resistance, appearance stability, and structural strength. Existing packaging shells are mostly made of plastic injection molded parts, and common problems after repeated contact with alcohol media include: surface gloss loss, whitening, stress cracking, slight dimensional warping, and decreased impact toughness leading to an increased risk of drop damage. At the same time, the trend towards lightweighting and thin-walled materials requires materials to maintain high rigidity / high flexural strength while also possessing sufficient notched impact strength and interfacial stability. Improving one indicator often sacrifices another, making the synergistic improvement of alcohol resistance and mechanical properties a key technological direction.

[0003] Currently, commonly used cosmetic packaging shell materials mainly include ABS, PP, PETG, PC and their alloy systems. Some also use bio-based or biodegradable materials to meet environmental protection requirements. Common modification methods to improve alcohol resistance and strength include: using elastomers to toughen and improve impact resistance, adding conventional inorganic fillers to improve rigidity and dimensional stability, using common compatibilizers or coupling agents to improve dispersion in multiphase systems, and surface coatings / spraying varnishes, UV-cured coatings and other methods to improve surface solvent resistance and abrasion resistance. In addition, solvent effects can also be reduced by increasing crystallinity, blending with other polyesters or adding hydrophobic additives.

[0004] In existing technologies, elastomer toughening relies on the energy consumption of forming a soft phase. However, the soft phase is usually more easily wetted and swollen by alcohol solvents, which reduces the material modulus. At the same time, the multiphase interface is prone to interfacial debonding and microporous formation under the action of alcohol medium, resulting in a simultaneous decrease in impact strength and flexural strength after immersion. Although ordinary inorganic fillers can improve rigidity, their surface compatibility with polar polyester matrices such as PLA is limited, and they are prone to agglomeration and the formation of stress concentration points, which limits the improvement of notched impact strength. Furthermore, interfacial defects provide channels for solvent penetration, causing whitening, cracking and performance degradation.

[0005] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide an alcohol-resistant cosmetic packaging shell material based on polylactic acid modification and its preparation method, in order to solve the technical problem that the alcohol resistance and mechanical properties of existing cosmetic packaging shell materials need to be further improved.

[0007] The objective of this invention can be achieved through the following technical solutions: Alcohol-resistant cosmetic packaging shell material based on polylactic acid (PLA) includes the following components by weight: 65-85 parts alcohol-resistant modified PLA, 10-15 parts PLA-modified sepiolite, 3-5 parts fluorosilicone epoxy compatibilizer and 1-3 parts excipients. The alcohol-resistant modified polylactic acid is prepared by the following steps: A1. Place 2-chloro-N-(2-hydroxyethyl)-acetamide and L-lactide into a reaction vessel, add stannous octoate, connect a vacuum distillation apparatus and stir, react at 150-170℃ for 4-6 h, and then process to obtain chloroacetamide-terminated polylactic acid. A2. Chloroacetamide-terminated polylactic acid and N,N-dimethylformamide were placed in a reaction vessel under nitrogen atmosphere and stirred. The reaction vessel was heated to 40-50℃, and polyetheramine T403, triethylamine and potassium iodide were added. The reaction was kept at this temperature for 0.5-1h, and the alcohol-resistant modified polylactic acid was obtained after post-treatment.

[0008] The reaction formula for preparing alcohol-resistant modified polylactic acid is as follows: Further, in step A1, the ratio of 2-chloro-N-(2-hydroxyethyl)-acetamide, L-lactide, and stannous octoate is 0.8-1.2g:80-120g:0.1-0.12g. The post-processing steps include: after the reaction is completed, wait for the reaction system to cool to room temperature, add 100-120mL of dichloromethane and stir for 3-5min, then add 600-800mL of anhydrous methanol to precipitate the precipitate, filter, wash with methanol 2-4 times, transfer to a drying oven at 50-60℃, and dry to constant weight to obtain chloroacetamide-terminated polylactic acid; Further, in step A2, the ratio of chloroacetamide-terminated polylactic acid, N,N-dimethylformamide, polyetheramine T403, triethylamine, and potassium iodide is 6-10g:100-120mL:0.5-1g:0.2-0.4g:0.1-0.2g. The post-treatment step includes: after the reaction is completed, the reaction system is cooled to room temperature, filtered, the filtrate is added to 500-600mL of anhydrous methanol to precipitate, filtered, the filter cake is washed 2-4 times with n-heptane, and vacuum dried at 40-50℃ for 18-20h to obtain alcohol-resistant modified polylactic acid.

[0009] Furthermore, the preparation method of the fluorosilicone epoxy compatibilizer is as follows: 1H,1H,2H,2H-perfluorooctyltriethoxysilane, deionized water and ethanol are placed in a reaction vessel and stirred. Acetic acid solution is added to adjust the pH to 4-5. The reaction vessel is heated to 35-45℃ and kept at this temperature for 0.5-1h. Low-boiling substances are removed by vacuum distillation. Hydroxyl-terminated polydimethylsiloxane and toluene are added and kept at this temperature for 1-2h. 3-glycidyl etheroxypropyltrimethoxysilane is added and kept at this temperature for 0.5-1h. The fluorosilicone epoxy compatibilizer is obtained after post-treatment.

[0010] Furthermore, the ratio of 1H,1H,2H,2H-perfluorooctyltriethoxysilane, deionized water, ethanol, hydroxyl-terminated polydimethylsiloxane, toluene, and 3-glycidyl etheroxypropyltrimethoxysilane is 1-2g:0.5-1mL:20-40mL:4-6g:25-30mL:0.5-1g, and the concentration of the acetic acid solution is 3-5wt%. The post-processing steps include: after the reaction is completed, the reaction vessel is heated to 110-120℃, and the mixture is distilled under reduced pressure until no liquid is collected, to obtain the fluorosilicone epoxy compatibilizer.

[0011] Furthermore, the polylactic acid-modified sepiolite is prepared by the following method: B1. Place sepiolite, hydrochloric acid and deionized water in a reaction vessel and stir. Heat the reaction vessel to 75-85℃ and keep it at that temperature for 1-2 hours. After post-treatment, acid-treated sepiolite is obtained. B2. Place acid-treated sepiolite, L-lactide, stannous octoate and toluene in a nitrogen-protected reactor and stir. Heat the reactor to reflux and maintain the temperature for 20-24 hours. Post-treatment yields polylactic acid-modified sepiolite.

[0012] Further, in step B1, the ratio of sepiolite, hydrochloric acid and deionized water is 10-15g:40-50mL:140-160mL, the concentration of hydrochloric acid is 36-38wt%, and the post-treatment step includes: after the reaction is completed, the mixture is filtered while hot, the filter cake is washed with deionized water until neutral, transferred to a freeze dryer at a temperature of -60℃, and freeze-dried for 36-48h to obtain acid-treated sepiolite; Further, in step B2, the ratio of acid-treated sepiolite, L-lactide, stannous octoate, and toluene is 4-6 g: 10-12 g: 0.06-0.08 g: 400-600 mL. The post-treatment steps include: after the reaction is completed, the reaction is allowed to cool to room temperature, filtered, the filter cake is washed 2-4 times with dichloromethane, transferred to an oven at 50-60°C, dried to constant weight, the product is placed in a Soxhlet extractor, and Soxhlet extraction is performed with dichloromethane as the extraction solvent for 24-48 h. After extraction, the product is transferred to an oven at 50-60°C and dried to constant weight to obtain polylactic acid modified sepiolite.

[0013] This invention also proposes a method for preparing an alcohol-resistant cosmetic packaging shell material based on polylactic acid modification, comprising the following steps: S1. Add alcohol-modified polylactic acid, polylactic acid-modified sepiolite, fluorosilicone epoxy compatibilizer and excipients to a high-speed homogenizer and mix at room temperature for 5-10 minutes to obtain a premix. S2. Add the premixed material to a twin-screw melt extruder, melt extrude, granulate, and obtain cosmetic packaging shell material.

[0014] Furthermore, the excipients are composed of plasticizer, lubricant and colorant in a mass ratio of 10:3:2. The plasticizer is one or more of dibutyl phthalate, diisononyl phthalate and dioctyl sebacate. The lubricant is one or more of fatty acid amide, oleamide and polyethylene wax. The colorant is one or more of ultramarine, phthalocyanine blue and phthalocyanine green. Furthermore, the temperature of the eight temperature zones of the twin-screw extruder from the feed inlet to the discharge outlet is 150℃, 150℃, 165℃, 165℃, 175℃, 175℃, 185℃, and 185℃ respectively. The main engine speed of the twin-screw extruder is 200-300 rpm, and the pressure is 80-120 bar.

[0015] The present invention has the following beneficial effects: 1. The alcohol-resistant modified polylactic acid prepared in this invention introduces flexible polyetheramine segments at the ends of polylactic acid molecules, which significantly improves the stability of the packaging material when in contact with alcohol media while maintaining the integrity of the main polylactic acid structure. The introduction of flexible polyether segments can reduce the internal stress concentration between polylactic acid molecules, improve the impact resistance of the packaging material, and the polyether segments have a certain buffering and dispersing effect on alcohol solvents, effectively weakening the swelling and erosion of polylactic acid bonds by alcohol solvents, reducing volume changes, whitening and mechanical property degradation. In addition, the controllable modification of the end groups improves the interfacial bonding strength between polylactic acid, polylactic acid-modified sepiolite and fluorosilicone epoxy compatibilizer, reduces interfacial defects, significantly reduces the permeation channels provided by solvents, and further improves the overall alcohol solvent resistance of the packaging material.

[0016] 2. The polylactic acid-modified sepiolite of the present invention is obtained by grafting lactide onto the surface of sepiolite through ring-opening polymerization after acid treatment. Through acidification, the number of hydroxyl groups on the surface of sepiolite increases, allowing polylactic acid segments to be grafted onto the surface of sepiolite via chemical bonds. This significantly improves the interfacial compatibility between the inorganic filler and the polylactic acid matrix, avoiding the problems of easy agglomeration and interfacial debonding of traditional inorganic fillers. Furthermore, the needle-like rigid structure of the polylactic acid-modified sepiolite constructs a stable skeletal support network within the material, which can effectively improve the mechanical properties of the packaging shell material. This inorganic skeleton can also form tortuous physical barrier paths in the matrix, significantly extending the diffusion distance of alcohols within the packaging shell material, reducing the solvent penetration rate, and improving the alcohol resistance of the packaging shell material.

[0017] 3. The fluorosilicone epoxy compatibilizer of the present invention uses a flexible siloxane backbone as its framework, which significantly improves the fluidity and structural continuity of the polylactic acid-based system during melt processing, reduces the risk of phase separation caused by polarity differences in multi-component blends, and is conducive to obtaining a uniform and dense material structure. Furthermore, the epoxy functional groups introduced into the compatibilizer molecule can chemically react with the active groups at the ends of the alcohol-resistant modified polylactic acid molecules and the polylactic acid-modified sepiolite during processing, establishing a stable chemical bridge between the organic matrix and the inorganic filler, significantly improving the interfacial bonding strength and reducing interfacial defects. At the same time, the fluorinated groups and siloxane segments contained in the fluorosilicone epoxy compatibilizer endow the material with a lower surface energy, which can effectively reduce the wetting and adsorption of polar solvents such as ethanol on the material surface, slow down the process of solvent penetration into the material interior, and improve the alcohol resistance of the packaging shell material. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The polyetheramine T403 used in this invention was purchased from Greenlink (Jining) Chemical Technology Co., Ltd., with product number AL630330262739, model T403, and brand Huntsman. The hydroxyl-terminated polydimethylsiloxane used in this invention was purchased from Wuhan Shuer Biotechnology Co., Ltd., with an effective ingredient content of 99% and a viscosity of 60-70. The sepiolite used in this invention was purchased from Lingshou County Tianlong Mineral Products Processing Plant. It is a white powder with a particle size of 325 mesh. The L-lactide used in this invention was purchased from Hubei Xingyan New Material Technology Co., Ltd., with a molecular weight of 144.12500 and CAS number 13076-17-0.

[0020] Example 1 This embodiment provides a method for preparing alcohol-resistant modified polylactic acid, including the following steps: Step I: Preparation of chloroacetamide-terminated polylactic acid Weigh 8g of 2-chloro-N-(2-hydroxyethyl)-acetamide and 800g of L-lactide and place them in a reaction vessel. Add 1g of stannous octoate, connect a vacuum distillation apparatus and stir. React at 150℃ for 4h. After the reaction is complete, wait for the reaction system to cool to room temperature, add 1000mL of dichloromethane and stir for 3min. Then add 6000mL of anhydrous methanol to precipitate the precipitate. Filter the precipitate, wash it twice with methanol, transfer it to a drying oven at 50℃, and dry it to constant weight to obtain chloroacetamide-terminated polylactic acid.

[0021] Under the catalysis of stannous octoate, the hydroxyl group of 2-chloro-N-(2-hydroxyethyl)-acetamide initiates the ring-opening polymerization of L-lactide to form modified polylactic acid with polylactic acid as the main chain and α-chloroamide at the end groups.

[0022] Step II: Preparation of alcohol-resistant modified polylactic acid Weigh 60g of chloroacetamide-terminated polylactic acid and 1000mL of N,N-dimethylformamide and place them in a nitrogen-protected reactor and stir. Heat the reactor to 40℃, add 5g of polyetheramine T403, 2g of triethylamine and 1g of potassium iodide, and keep the reaction at this temperature for 0.5h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, add 5000mL of anhydrous methanol to precipitate, filter, wash the filter cake twice with n-heptane, and vacuum dry at 40℃ for 18h to obtain alcohol-resistant modified polylactic acid.

[0023] Under the synergistic effect of potassium iodide and triethylamine, chloroacetamide-terminated polylactic acid undergoes a nucleophilic substitution reaction with polyetheramine in a polar solvent. The α-chloroamide is replaced by amine-containing functional groups, and flexible polyether segments are introduced into the end of the polylactic acid molecule to obtain alcohol-resistant modified polylactic acid.

[0024] By introducing α-chloroamide, polylactic acid backbone, and polyetheramine flexible segments step by step, polylactic acid can simultaneously obtain controllable end-group activity. Among them, α-chloroamide improves the subsequent grafting efficiency, ring-opening polymerization ensures the integrity of polylactic acid backbone, and polypropylene glycol segments in terminal amine enhance the alcohol resistance and interfacial stability of shell material.

[0025] Example 2 This embodiment provides a method for preparing alcohol-resistant modified polylactic acid, including the following steps: Step I: Preparation of chloroacetamide-terminated polylactic acid Weigh 10g of 2-chloro-N-(2-hydroxyethyl)-acetamide and 1000g of L-lactide and place them in a reaction vessel. Add 1.1g of stannous octoate, connect a vacuum distillation apparatus and stir. React at 160℃ for 5h. After the reaction is complete, wait for the reaction system to cool to room temperature, add 1100mL of dichloromethane and stir for 4min. Then add 7000mL of anhydrous methanol to precipitate the precipitate. Filter the precipitate, wash it three times with methanol, transfer it to a dryer at 55℃, and dry it to constant weight to obtain chloroacetamide-terminated polylactic acid.

[0026] Step II: Preparation of alcohol-resistant modified polylactic acid Weigh out 80g of chloroacetamide-terminated polylactic acid and 1100mL of N,N-dimethylformamide and place them in a nitrogen-protected reactor. Stir the reactor and heat it to 45°C. Add 7.5g of polyetheramine T403, 3g of triethylamine and 1.5g of potassium iodide. Keep the reactor at this temperature for 1 hour. After the reaction is complete, wait for the reaction system to cool to room temperature and filter it. Add the filtrate to 5500mL of anhydrous methanol to precipitate the precipitate. Filter the precipitate and wash it three times with n-heptane. Dry it under vacuum at 45°C for 19 hours to obtain alcohol-resistant modified polylactic acid.

[0027] Example 3 This embodiment provides a method for preparing alcohol-resistant modified polylactic acid, including the following steps: Step I: Preparation of chloroacetamide-terminated polylactic acid Weigh 12g of 2-chloro-N-(2-hydroxyethyl)-acetamide and 1200g of L-lactide and place them in a reaction vessel. Add 1.2g of stannous octoate, connect a vacuum distillation apparatus and stir. React at 170℃ for 6h. After the reaction is complete, wait for the reaction system to cool to room temperature, add 1200mL of dichloromethane and stir for 5min. Then add 8000mL of anhydrous methanol to precipitate the precipitate. Filter the precipitate, wash it 4 times with methanol, transfer it to a drying oven at 60℃, and dry it to constant weight to obtain chloroacetamide-terminated polylactic acid.

[0028] Step II: Preparation of alcohol-resistant modified polylactic acid Weigh 100g of chloroacetamide-terminated polylactic acid and 1200mL of N,N-dimethylformamide and place them in a nitrogen-protected reactor and stir. Heat the reactor to 50℃, add 10g of polyetheramine T403, 4g of triethylamine and 2g of potassium iodide, and keep the reaction at this temperature for 1h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, add 6000mL of anhydrous methanol to precipitate, filter, wash the filter cake 4 times with n-heptane, and vacuum dry at 50℃ for 20h to obtain alcohol-resistant modified polylactic acid.

[0029] Example 4 This embodiment provides a method for preparing polylactic acid-modified sepiolite, including the following steps: Step ①: Preparation of acid-treated sepiolite Weigh out 100g of sepiolite, 400mL of 36wt% hydrochloric acid and 1400mL of deionized water and place them in a reaction vessel and stir. Heat the reaction vessel to 75℃ and keep it at that temperature for 1h. After the reaction is complete, filter while hot. Wash the filter cake with deionized water until neutral and transfer it to a freeze dryer at -60℃. Freeze dry for 36h to obtain acid-treated sepiolite.

[0030] Step ②: Preparation of polylactic acid modified sepiolite Weigh out 40g of acid-treated sepiolite, 100g of L-lactide, 0.6g of stannous octoate, and 4000mL of toluene and place them in a nitrogen-protected reactor. Stir the reactor and heat it to reflux. Maintain the temperature for 20 hours. After the reaction is complete, allow the mixture to cool to room temperature, filter it, wash the filter cake twice with dichloromethane, transfer it to an oven at 50°C, and dry it to constant weight. Place the product in a Soxhlet extractor and extract it with dichloromethane as the extraction solvent for 24 hours. After extraction, transfer it to an oven at 50°C and dry it to constant weight to obtain polylactic acid-modified sepiolite.

[0031] Impurity ions in sepiolite are removed by dissolving it with hydrochloric acid, and exchangeable cations in the structure are partially removed. This exposes and improves the reactivity accessibility of hydroxyl groups on the sepiolite surface, increasing the effective specific surface area. Furthermore, under the catalysis of stannous octoate and an inert atmosphere, lactide undergoes surface-initiated ring-opening polymerization at the hydroxyl sites on the acid-treated sepiolite surface, causing polylactic acid segments to be covalently grafted onto the surface, resulting in polylactic acid-modified sepiolite.

[0032] Introducing polylactic acid (PLA) segments that match the structure of PLA onto the surface of sepiolite enables PLA-modified sepiolite to achieve good dispersion and interfacial compatibility in PLA-based packaging shell materials. This reduces interfacial defects caused by inorganic fillers, which is beneficial to improving the mechanical properties of the shell material. Furthermore, the rigid skeleton of sepiolite constructs a physical barrier network in the matrix, extending the diffusion path of solvent molecules within the material and improving the solvent resistance of the shell material.

[0033] Example 5 This embodiment provides a method for preparing polylactic acid-modified sepiolite, including the following steps: Step ①: Preparation of acid-treated sepiolite Weigh 125g of sepiolite, 450mL of 37wt% hydrochloric acid and 1500mL of deionized water and place them in a reaction vessel and stir. Heat the reaction vessel to 80℃ and keep it at that temperature for 1.5h. After the reaction is complete, filter while hot. Wash the filter cake with deionized water until neutral and transfer it to a freeze dryer at -60℃. Freeze dry for 42h to obtain acid-treated sepiolite.

[0034] Step ②: Preparation of polylactic acid modified sepiolite Weigh out 50g of acid-treated sepiolite, 110g of L-lactide, 0.7g of stannous octoate, and 6000mL of toluene and place them in a nitrogen-protected reactor. Stir the reactor and heat it to reflux. Maintain the temperature for 22 hours. After the reaction is complete, allow the mixture to cool to room temperature, filter it, wash the filter cake three times with dichloromethane, transfer it to an oven at 55°C, and dry it to constant weight. Place the product in a Soxhlet extractor and perform Soxhlet extraction with dichloromethane as the extraction solvent for 36 hours. After extraction, transfer the product to an oven at 55°C and dry it to constant weight to obtain polylactic acid-modified sepiolite.

[0035] Example 6 This embodiment provides a method for preparing polylactic acid-modified sepiolite, including the following steps: Step ①: Preparation of acid-treated sepiolite Weigh out 150g of sepiolite, 500mL of 38wt% hydrochloric acid and 1600mL of deionized water and place them in a reaction vessel and stir. Heat the reaction vessel to 85℃ and keep it at that temperature for 2 hours. After the reaction is complete, filter while hot. Wash the filter cake with deionized water until it is neutral and transfer it to a freeze dryer at -60℃. Freeze dry for 48 hours to obtain acid-treated sepiolite.

[0036] Step ②: Preparation of polylactic acid modified sepiolite Weigh out 60g of acid-treated sepiolite, 120g of L-lactide, 0.8g of stannous octoate, and 8000mL of toluene and place them in a nitrogen-protected reactor. Stir the reactor and heat it to reflux. Maintain the temperature for 24 hours. After the reaction is complete, allow the mixture to cool to room temperature, filter it, wash the filter cake four times with dichloromethane, transfer it to an oven at 60℃, and dry it to constant weight. Place the product in a Soxhlet extractor and perform Soxhlet extraction with dichloromethane as the extraction solvent for 48 hours. After extraction, transfer the product to an oven at 60℃ and dry it to constant weight to obtain polylactic acid-modified sepiolite.

[0037] Example 7 This embodiment provides a method for preparing an alcohol-resistant cosmetic packaging shell material based on polylactic acid modification, including the following steps: Step 1: Preparation of fluorosilicone epoxy compatibilizer Weigh 10g of 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 5mL of deionized water, and 200mL of ethanol and place them in a reaction vessel. Stir the mixture and add 3wt% acetic acid solution to adjust the pH to 4. Heat the reaction vessel to 35℃ and maintain the temperature for 0.5h. Remove low-boiling substances by vacuum distillation. Add 40g of hydroxyl-terminated polydimethylsiloxane and 250mL of toluene and maintain the temperature for 1h. Add 5g of 3-glycidyl etheroxypropyltrimethoxysilane and maintain the temperature for 0.5h. After the reaction is complete, heat the reaction vessel to 110℃ and distill under reduced pressure until no liquid is collected, thus obtaining the fluorosilicone epoxy compatibilizer.

[0038] Under weakly acidic conditions, perfluorooctyltriethoxysilane first undergoes hydrolysis to generate silanol, and then undergoes pre-condensation to form a fluorinated siloxane structure. Hydroxyl-terminated polydimethylsiloxane undergoes a condensation reaction with the silanol groups of the fluorinated siloxane in the system. Finally, an epoxy-containing silane coupling agent is added, and the hydrolyzed silanol continues to co-condense with the siloxane structure in the system, introducing epoxy functional groups to obtain a compatibilizer with a fluorinated siloxane skeleton and epoxy groups.

[0039] Introducing fluorinated groups and epoxy functional groups into hydrophobic siloxane segments enables the compatibilizer to possess both low surface energy and reactive active sites. The fluorinated groups can reduce the surface energy of the packaging material, the siloxane segments improve the structural continuity and processing adaptability of the system, and the epoxy functional groups provide a reaction basis for subsequent chemical bonding with the matrix material, thereby improving the alcohol resistance and mechanical properties of the packaging material.

[0040] Step 2: Preparation of premix Diisononyl phthalate, oleamide and phthalocyanine green were mixed evenly in a mass ratio of 10:3:2 to obtain the excipient, which was then set aside. Weigh out the following amounts by weight: 65 parts of alcohol-modified polylactic acid prepared in Example 1, 10 parts of polylactic acid-modified sepiolite prepared in Example 3, 3 parts of fluorosilicone epoxy compatibilizer, and 1 part of excipients. Add them to a high-speed homogenizer and mix at room temperature for 5 minutes to obtain a premix.

[0041] Step 3: Preparation of cosmetic packaging shell material The premixed material is added to a twin-screw melt extruder, melt-extruded, and granulated to obtain cosmetic packaging shell material; The twin-screw extruder has eight temperature zones from the feed inlet to the discharge outlet, with temperatures of 150℃, 150℃, 165℃, 165℃, 175℃, 175℃, 185℃, and 185℃ respectively. The main motor speed of the twin-screw extruder is 200 rpm, and the pressure is 80 bar.

[0042] Example 8 This embodiment provides a method for preparing an alcohol-resistant cosmetic packaging shell material based on polylactic acid modification, including the following steps: Step 1: Preparation of fluorosilicone epoxy compatibilizer Weigh 15g of 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 7.5mL of deionized water, and 300mL of ethanol and place them in a reaction vessel. Stir the mixture and add 4wt% acetic acid solution to adjust the pH to 4.5. Heat the reaction vessel to 40℃ and maintain the temperature for 1h. Remove low-boiling substances by vacuum distillation. Add 50g of hydroxyl-terminated polydimethylsiloxane and 275mL of toluene and maintain the temperature for 1.5h. Add 7.5g of 3-glycidyl etheroxypropyltrimethoxysilane and maintain the temperature for 1h. After the reaction is complete, heat the reaction vessel to 115℃ and distill under reduced pressure until no liquid is collected, thus obtaining the fluorosilicone epoxy compatibilizer.

[0043] Step 2: Preparation of premix Diisononyl phthalate, oleamide and phthalocyanine green were mixed evenly in a mass ratio of 10:3:2 to obtain the excipient, which was then set aside. Weigh out the following by weight: 75 parts of alcohol-modified polylactic acid prepared in Example 2, 12.5 parts of polylactic acid-modified sepiolite prepared in Example 4, 4 parts of fluorosilicone epoxy compatibilizer, and 2 parts of excipients. Add them to a high-speed homogenizer and mix at room temperature for 7 minutes to obtain a premix.

[0044] Step 3: Preparation of cosmetic packaging shell material The premixed material is added to a twin-screw melt extruder, melt-extruded, and granulated to obtain cosmetic packaging shell material; The twin-screw extruder has eight temperature zones from the feed inlet to the discharge outlet, with temperatures of 150℃, 150℃, 165℃, 165℃, 175℃, 175℃, 185℃, and 185℃ respectively. The main motor speed of the twin-screw extruder is 250 rpm, and the pressure is 100 bar.

[0045] Example 9 This embodiment provides a method for preparing an alcohol-resistant cosmetic packaging shell material based on polylactic acid modification, including the following steps: Step 1: Preparation of fluorosilicone epoxy compatibilizer Weigh 20g of 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 10mL of deionized water, and 400mL of ethanol and place them in a reaction vessel. Stir the mixture and add 5wt% acetic acid solution to adjust the pH to 5. Heat the reaction vessel to 45℃ and maintain the temperature for 1h. Remove low-boiling substances by vacuum distillation. Add 60g of hydroxyl-terminated polydimethylsiloxane and 300mL of toluene and maintain the temperature for 2h. Add 10g of 3-glycidyl etheroxypropyltrimethoxysilane and maintain the temperature for 1h. After the reaction is complete, heat the reaction vessel to 120℃ and distill under reduced pressure until no liquid is collected, thus obtaining the fluorosilicone epoxy compatibilizer.

[0046] Step 2: Preparation of premix Diisononyl phthalate, oleamide and phthalocyanine green were mixed evenly in a mass ratio of 10:3:2 to obtain the excipient, which was then set aside. Weigh out the following amounts by weight: 85 parts of alcohol-modified polylactic acid prepared in Example 3, 15 parts of polylactic acid-modified sepiolite prepared in Example 6, 5 parts of fluorosilicone epoxy compatibilizer, and 3 parts of excipients. Add them to a high-speed homogenizer and mix at room temperature for 10 minutes to obtain a premix.

[0047] Step 3: Preparation of cosmetic packaging shell material The premixed material is added to a twin-screw melt extruder, melt-extruded, and granulated to obtain cosmetic packaging shell material; The twin-screw extruder has eight temperature zones with temperatures ranging from the feed inlet to the discharge outlet: 150°C, 150°C, 165°C, 165°C, 175°C, 175°C, 185°C, and 185°C. The main motor speed of the twin-screw extruder is 300 rpm, and the pressure is 120 bar.

[0048] Comparative Example 1 The difference between this comparative example and Example 9 is that, in step (2) when preparing the premix, commercially available polylactic acid is used in an equal amount to replace alcohol-resistant modified polylactic acid.

[0049] Comparative Example 2 The difference between this comparative example and Example 9 is that polylactic acid modified sepiolite was omitted in step (2) when preparing the premix.

[0050] Comparative Example 3 The difference between this comparative example and Example 9 is that the fluorosilicone epoxy compatibilizer was omitted in step (2) when preparing the premix.

[0051] Performance testing: According to standard T / SHPTA 057-2023 "Special Material for Modified Polypropylene (PP) for Plastic Power Battery Shells", the cosmetic packaging shell materials prepared in Examples 7-9 and Comparative Examples 1-3 were prepared into samples, and the cantilever beam notched impact strength and flexural strength of the samples were measured. According to standard GB / T 11547-2008 "Determination of the resistance of plastics to liquid chemical reagents", the cosmetic packaging shell material samples prepared in Examples 7-9 and Comparative Examples 1-3 were immersed in a 75wt% ethanol aqueous solution. The volume expansion rate and appearance change grade of the samples after the immersion test were measured. The cantilever beam notched impact strength and flexural strength of the samples after the immersion test were determined according to standard T / SHPTA 057-2023. See Table 1 for specific data.

[0052] Data Analysis: A comparative analysis of Table 1 above revealed that the cantilever beam notched impact strength of the packaging shell material prepared by this invention is 14.23 kJ·m. -2The flexural strength is 92.65 MPa, and the notched impact strength of the cantilever beam after immersion testing is 12.98 kJ·m. -2 It exhibits a flexural strength of 81.29 MPa and a volume expansion rate of 1.12%, while maintaining no change in appearance. The cosmetic packaging shell material prepared by this invention uses polylactic acid as the matrix and is prepared through multi-level synergistic modification. First, 2-chloro-N-(2-hydroxyethyl)-acetamide is prepared by reacting chloroacetyl chloride with ethanolamine, which initiates the ring-opening polymerization of lactide to obtain chloroacetamide-terminated polylactic acid. Then, it undergoes a nucleophilic substitution reaction with polyetheramine to introduce flexible polyether segments at the end of the polylactic acid molecule, thus obtaining alcohol-resistant modified polylactic acid. Next, sepiolite is acid-activated and the ring-opening polymerization of lactide is initiated in situ on its surface, so that the polylactic acid segments are chemically grafted onto the surface of sepiolite, resulting in polylactic acid-modified sepiolite that is highly compatible with the matrix. At the same time, a fluorosilicone epoxy compatibilizer is prepared by the condensation reaction of fluorosilane, siloxane and epoxysilane. Finally, the alcohol-resistant modified polylactic acid, polylactic acid-modified sepiolite, fluorosilicone epoxy compatibilizer and excipients are premixed and melt-extruded by twin screw extrusion to obtain a cosmetic packaging shell material with both alcohol resistance and mechanical properties.

[0053] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

[0054] 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.

[0055] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A polylactic acid-modified alcohol-resistant cosmetic packaging shell material, characterized in that, It comprises the following components by weight: 65-85 parts alcohol-resistant modified polylactic acid, 10-15 parts polylactic acid modified sepiolite, 3-5 parts fluorosilicone epoxy compatibilizer and 1-3 parts excipients. The alcohol-resistant modified polylactic acid is prepared by the following steps: A1. Place 2-chloro-N-(2-hydroxyethyl)-acetamide and L-lactide into a reaction vessel, add stannous octoate, connect a vacuum distillation apparatus and stir, react at 150-170℃ for 4-6 h, and then process to obtain chloroacetamide-terminated polylactic acid. A2. Chloroacetamide-terminated polylactic acid and N,N-dimethylformamide were placed in a reaction vessel under nitrogen atmosphere and stirred. The reaction vessel was heated to 40-50℃, and polyetheramine T403, triethylamine and potassium iodide were added. The reaction was kept at this temperature for 0.5-1h, and the alcohol-resistant modified polylactic acid was obtained after post-treatment.

2. The polylactic acid-modified alcohol-resistant cosmetic packaging shell material according to claim 1, characterized in that, In step A1, the ratio of 2-chloro-N-(2-hydroxyethyl)-acetamide, L-lactide and stannous octoate is 0.8-1.2g:80-120g:0.1-0.12g.

3. The polylactic acid-modified alcohol-resistant cosmetic packaging shell material according to claim 1, characterized in that, In step A2, the ratio of the amount of chloroacetamide-terminated polylactic acid, N,N-dimethylformamide, polyetheramine T403, triethylamine and potassium iodide is 6-10g:100-120mL:0.5-1g:0.2-0.4g:0.1-0.2g.

4. The polylactic acid-modified alcohol-resistant cosmetic packaging shell material according to claim 1, characterized in that, The preparation method of the fluorosilicone epoxy compatibilizer is as follows: 1H,1H,2H,2H-perfluorooctyltriethoxysilane, deionized water and ethanol are placed in a reaction vessel and stirred. Acetic acid solution is added to adjust the pH to 4-5. The reaction vessel is heated to 35-45℃ and kept at this temperature for 0.5-1h. Low-boiling substances are removed by vacuum distillation. Hydroxyl-terminated polydimethylsiloxane and toluene are added and kept at this temperature for 1-2h. 3-glycidyl etheroxypropyltrimethoxysilane is added and kept at this temperature for 0.5-1h. The fluorosilicone epoxy compatibilizer is obtained after post-treatment.

5. The polylactic acid-modified alcohol-resistant cosmetic packaging shell material according to claim 4, characterized in that, The ratio of 1H,1H,2H,2H-perfluorooctyltriethoxysilane, deionized water, ethanol, hydroxyl-terminated polydimethylsiloxane, toluene, and 3-glycidyl etheroxypropyltrimethoxysilane used is 1-2g:0.5-1mL:20-40mL:4-6g:25-30mL:0.5-1g, and the concentration of the acetic acid solution is 3-5wt%.

6. The polylactic acid-modified alcohol-resistant cosmetic packaging shell material according to claim 1, characterized in that, The polylactic acid-modified sepiolite was prepared by the following method: B1. Place sepiolite, hydrochloric acid and deionized water in a reaction vessel and stir. Heat the reaction vessel to 75-85℃ and keep it at that temperature for 1-2 hours. After post-treatment, acid-treated sepiolite is obtained. B2. Place acid-treated sepiolite, L-lactide, stannous octoate and toluene in a nitrogen-protected reactor and stir. Heat the reactor to reflux and maintain the temperature for 20-24 hours. Post-treatment yields polylactic acid-modified sepiolite.

7. The polylactic acid-modified alcohol-resistant cosmetic packaging shell material according to claim 6, characterized in that, In step B1, the ratio of sepiolite, hydrochloric acid, and deionized water is 10-15g:40-50mL:140-160mL, and the concentration of hydrochloric acid is 36-38wt%; in step B2, the ratio of acid-treated sepiolite, L-lactide, stannous octoate, and toluene is 4-6g:10-12g:0.06-0.08g:400-600mL.

8. A method for preparing an alcohol-resistant cosmetic packaging shell material based on polylactic acid modification as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Add alcohol-modified polylactic acid, polylactic acid-modified sepiolite, fluorosilicone epoxy compatibilizer and excipients to a high-speed homogenizer and mix at room temperature for 5-10 minutes to obtain a premix. S2. Add the premixed material to a twin-screw melt extruder, melt extrude, granulate, and obtain cosmetic packaging shell material.

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