Method for preparing high-impact cosmetic bottle material by regenerating PET (Polyethylene Terephthalate)

Abstract

The invention discloses a method for preparing a high-impact-resistance cosmetic bottle material through PET regeneration, belongs to the technical field of PET regeneration and utilization, and aims at solving the technical problem that in the prior art, when PET is regenerated for preparing an impact-resistance cosmetic material, the mechanical property and the transparency of the material need to be further improved. Comprising the following steps: crushing waste PET into PET powder with the particle size of 2-5mm, and then performing alcoholysis regeneration on the PET powder to obtain BHET. According to the invention, the waste PET is taken as a raw material, the regenerated PET with reaction activity is obtained through depolymerization, amination and repolymerization, and the regenerated PET is reinforced through the polyurethane elastomer and the activated silicon dioxide, so that the bending stress and the impact resistance of the cosmetic bottle material are effectively improved, and the transparency of the cosmetic bottle material is also improved; the high-valued application of the waste PET regenerated material in the field of high-end cosmetic packaging is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of PET recycling and utilization, and particularly relates to a method for recycling PET to prepare a high-impact cosmetic bottle material. Background Art

[0002] Polyethylene terephthalate (abbreviated as PET) is a thermoplastic polyester material with excellent comprehensive properties. Due to its high transparency, good mechanical strength, excellent chemical resistance, and convenient processing and molding, it is widely used in fields such as beverage bottles, cosmetic packaging, fibers, and films. The ester group structure in the PET molecular chain endows it with excellent organic solvent resistance, making it widely used in the cosmetic packaging industry.

[0003] The existing recycling methods of waste PET mainly include physical recycling and chemical recycling; the physical recycling process is simple, but multiple melt processing will lead to a decrease in molecular weight, a darker color, and a deterioration of properties; although chemical recycling can achieve structural reconstruction at the molecular level, the existing recycled PET products still generally have problems such as PET molecular chain breakage, an increase in end group defects, a decrease in molecular weight, a yellowing of color, and a decrease in crystallinity, resulting in a significant decline in both its mechanical properties and optical properties. In the application of cosmetic packaging, recycled PET often cannot balance high transparency and high strength and is difficult to be applied to high-demand transparent packaging materials.

[0004] In view of the technical deficiencies in this regard, a solution is proposed herein. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for recycling PET to prepare a high-impact cosmetic bottle material, which is used to solve the technical problem that the mechanical properties and transparent properties of the material need to be further improved when recycling PET to prepare an impact-resistant cosmetic material in the prior art.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A method for recycling PET to prepare a high-impact cosmetic bottle material includes the following steps: S1.粉碎废旧PET成粒径为2 - 5mm的PET粉末,然后对PET粉末进行醇解再生,得到BHET; S1. Crush waste PET into PET powder with a particle size of 2 - 5 mm, and then carry out alcoholysis regeneration on the PET powder to obtain BHET; S2、将BHET、乙二醇、2-(氨基甲基)丙烷-1,3-二醇和无水醋酸锌加入惰性气体氛围保护的聚合釜中搅拌,聚合釜升温至140 - 160℃,保温处理25 - 35min,向聚合釜中加入钛酸四丁酯,聚合釜升温至190 - 200℃,保温反应3 - 4h,聚合釜抽真空至-0.1MPa,反应釜继续升温至250℃,保温搅拌50 - 70min,挤出造粒,得到再生PET; S2. Add BHET, ethylene glycol, 2-(aminomethyl)propane-1,3-diol, and anhydrous zinc acetate into a polymerization kettle protected by an inert gas atmosphere and stir. Heat the polymerization kettle to 140 - 160 °C, carry out heat preservation treatment for 25 - 35 min, add tetrabutyl titanate into the polymerization kettle, heat the polymerization kettle to 190 - 200 °C, carry out heat preservation reaction for 3 - 4 h, evacuate the polymerization kettle to -0.1 MPa, continue to heat the reaction kettle to 250 °C, carry out heat preservation stirring for 50 - 70 min, and extrude and pelletize to obtain recycled PET; The synthesis reaction equation for recycled PET is as follows: S3. After drying recycled PET, polyurethane elastomer, activated silica, and auxiliary additives, mix them evenly in a twin-screw extruder and melt-mix for 30-50 seconds. Then, extrude and inject the mixture into the mold, hold the pressure for 8-12 seconds, cool for 15-20 seconds, and discharge the material to obtain cosmetic bottle material with a wall thickness of 3-4 mm.

[0007] Further, in step S1, the preparation method of BHET is as follows: PET powder, ethylene glycol, anhydrous zinc acetate and activated carbon are added to a high-pressure reactor under an inert gas atmosphere and stirred. After the reactor is sealed, the temperature is raised to 220-230℃, the pressure of the reactor is maintained at 0.18-0.22MPa, and the reaction is carried out for 3-4 hours. After post-processing, BHET is obtained.

[0008] Furthermore, the ratio of PET powder, ethylene glycol, anhydrous zinc acetate, and activated carbon is 1g:8-9mL:0.005g:0.2-0.3g. The post-treatment includes: after the reaction is complete, the temperature of the reaction system is cooled to 80-90℃, ethylene glycol is added to the reaction vessel for dilution, the mixture is filtered, 1wt% sodium dodecyl sulfate solution is added to the filtrate, the mixture is stirred and dispersed for 30-50 minutes, filtered again, the filter cake is washed three times with purified water and then transferred to a drying oven at 60-70℃ and dried to constant weight to obtain BHET.

[0009] Furthermore, in step S2, the weight ratio of BHET, ethylene glycol, 2-(aminomethyl)propane-1,3-diol, anhydrous zinc acetate, and tetrabutyl titanate is 10:2:3-4:0.1:0.1.

[0010] Further, in step S3, the weight ratio of the recycled PET, polyurethane elastomer, activated silica, and auxiliary additives is 70-80:30-36:5-7:2-3. The auxiliary additives consist of antioxidant, lubricant, nucleating agent, and fluorescent whitening agent in a weight ratio of 6:5:3:2:0.1. The antioxidant is BHT, the lubricant is polyethylene wax, the nucleating agent is NP-508, and the fluorescent whitening agent is OB-1. The temperature of the twin-screw extruder is 240-250℃ in zone I, 250-260℃ in zone II, 250-260℃ in zone III, and 260-270℃ in zone IV. The spindle speed of the twin-screw extruder is 60-80 rpm. The extrusion injection pressure is 90-100 MPa. The die temperature is 10-15℃, and the die holding pressure is 60-80 MPa.

[0011] Furthermore, the preparation method of polyurethane elastomer is as follows: under the protection of an inert gas atmosphere, BHET and toluene are mixed, the reaction system is heated to 70-80℃, and stirred until the system is dissolved. Isophorone diisocyanate is added to the reaction system, and the reaction is maintained for 30-50 min. Epoxy-modified polysiloxane is added to the reaction system, and the reaction is maintained for 2-3 h. 2-Hydroxymethyl-1,3-propanediol is added to the reaction system, and the reaction is maintained for 40-60 min. After post-treatment, polyurethane elastomer is obtained.

[0012] The synthesis reaction equation for polyurethane elastomers is as follows: In the formula: Furthermore, the ratio of BHET, toluene, epoxy-modified polysiloxane, and 2-hydroxymethyl-1,3-propanediol is 10g:50mL:3-4g:0.2g, and the amount of isophorone diisocyanate is 0.55 times the total molar amount of hydroxyl groups in BHET and epoxy-modified polysiloxane. The post-treatment includes: after the reaction is complete, the reaction system is heated to 80-90℃, and low-boiling substances are removed by vacuum evaporation to obtain polyurethane elastomer.

[0013] Furthermore, the preparation method of epoxy-modified polysiloxane is as follows: octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, 3-glycidyl etheroxypropylmethyldiethoxysilane, n-butyl titanate and deionized water are mixed, the reaction system is heated to 85-95℃, and the reaction is maintained at this temperature for 60-80 min. 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane is added to the reaction system, followed by post-treatment to obtain epoxy-modified polysiloxane.

[0014] The synthesis reaction equation for epoxy-modified polysiloxanes is as follows: Furthermore, the ratio of octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, 3-glycidyl etheroxypropylmethyldiethoxysilane, 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane, n-butyl titanate, and deionized water is 8g:4-5g:4g:2g:0.5g:0.2mL. The post-treatment includes: after the reaction is complete, the reaction system is cooled to room temperature, anhydrous ethanol is added to the reaction system, the mixture is stirred and dispersed for 20-30 minutes, the mixture is allowed to stand and separated, the oily substance is washed twice with purified water and transferred to a rotary evaporator with a water bath temperature of 70-80℃, the vacuum is drawn to -0.1MPa, and the low-boiling substances are removed by vacuum evaporation to obtain epoxy-modified polysiloxane.

[0015] Furthermore, the preparation method of activated silica is as follows: mix nano silica, γ-aminopropyltriethoxysilane and anhydrous ethanol, ultrasonically disperse for 40-50 min, add alkaline solution to the reaction system, keep the reaction at a warm temperature for 40-50 min, and then perform post-treatment to obtain activated silica.

[0016] Furthermore, the ratio of nano-silica, γ-aminopropyltriethoxysilane, anhydrous ethanol, and alkaline solution is 5g:1.8-2.1g:50mL:10mL, and the alkaline solution is a 3-5mol / L sodium hydroxide solution. The post-treatment includes: after the reaction is complete, the reaction system is cooled to room temperature, filtered, the filter cake is washed with purified water until neutral, dried, and the filter cake is transferred to a drying oven at 60-70℃ and dried to constant weight to obtain activated silica.

[0017] The present invention has the following beneficial effects: 1. The method for preparing high-impact cosmetic bottle materials from recycled PET of the present invention involves introducing 2-(aminomethyl)propane-1,3-diol into the recycled PET during the preparation process to achieve amylation modification of the molecular end groups, thereby enabling the recycled PET chain segments to simultaneously possess high crystallinity and reactivity. The introduction of amino groups significantly improves the interfacial bonding force between PET and polyurethane elastomers and epoxy-modified polysiloxane molecular chains while maintaining the intrinsic rigidity of PET. Through possible addition or etherification reactions between amino groups and epoxy and hydroxyl groups, chemical crosslinking or strong polar hydrogen bond interactions are formed between different phases, thereby forming a stable multiphase composite structure. This effectively improves the interfacial stress transfer efficiency, enabling the material to maintain high bending stress under bending loads and exhibit good impact resistance when subjected to impact. At the same time, amino modification reduces the adverse effects of molecular defects in recycled PET on optical properties and improves the transparency of cosmetic bottle materials prepared from recycled PET.

[0018] 2. The method for preparing high-impact cosmetic bottle materials from recycled PET of the present invention utilizes an epoxy-modified polysiloxane and a polyurethane elastomer to synergistically construct a reactive toughening system. The epoxy end groups in the epoxy-modified polysiloxane molecule can chemically react with amino-modified PET and polyurethane segments or form an interfacial interpenetrating structure, thereby forming a fine-scale distributed flexible phase. The polyurethane elastomer uses isophorone diisocyanate (IPDI) as the main chain linker, and its alicyclic structure gives the system high refractive index matching and low yellowing tendency. The two work together to form a micro-nano-scale interfacial layer structure, which can effectively absorb impact energy through multiple energy dissipation processes such as deformation and interpenetrating crosslinking under impact load, significantly improving the impact resistance of the material while maintaining optical transparency. At the same time, reactive toughening avoids large-scale phase separation, maintains the optical uniformity of the material, further improves the light transmittance of the material, and achieves simultaneous improvement in toughness and transparency.

[0019] 3. The method for preparing high-impact cosmetic bottle material from recycled PET of the present invention involves activating nano-silica with γ-aminopropyltriethoxysilane, forming an amino-modified polysiloxane coating on the activated nano-silica. The amino functional groups chemically or polarly bond with the recycled PET, polyurethane elastomer, and epoxy polysiloxane, forming a stable interfacial network structure. This allows the activated silica particles to be uniformly dispersed in the system. Furthermore, the numerous amino groups modified on the activated nano-silica particles can undergo ring-opening condensation with the epoxy groups, enhancing the cross-linking bond degree between material molecules and forming a cross-linked network within the material. This network acts as a reinforcement, enhancing the material's bending resistance and dimensional stability. Stability; moreover, the activated nano-silica particles have high surface energy, which can serve as heterogeneous nucleation centers in PET melt, promoting the rapid orientation and crystallization of PET molecular chains at more nucleation points during the cooling stage, thereby significantly refining the grain size, reducing the interspherulite spacing, and making the crystal distribution more uniform. The scattering of light between the crystal and amorphous interfaces is significantly reduced, and the intensity of scattered light is drastically reduced, thereby increasing the light transmittance and reducing the haze. The combination of twin-screw extrusion and rapid cooling molding process further suppresses excessive crystallization and phase aggregation, improving the light transmittance of the material. This results in a material with high strength, high impact resistance, and excellent transparent appearance, making it particularly suitable for cosmetic bottles where both mechanical properties and appearance are required. Detailed Implementation

[0020] 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] In this invention, the waste PET comes from PET beverage bottles; In this invention, NP-508 is sodium 2,2'-methylene bis(4,6-di-tert-butylphenyl) phosphate, CAS number 85209-91-2; In this invention, the fluorescent whitening agent OB-1 is 4,4'-bis(2-benzoxazolyl)stilbene, with CAS number 1533-45-5; In this invention, the particle size of nano-silica is 20-50 nm; In this invention, the polyethylene wax is polyethylene wax micro powder with a particle size D50 of 4-5 μm and the model number TW-F0041.

[0022] Example 1 This embodiment provides a method for preparing high-impact cosmetic bottle materials from recycled PET, specifically including the following steps: Step 1: Preparation of recycled PET Waste PET is crushed into PET powder with a particle size of 2-5mm; Weigh 1000g of PET powder, 8L of ethylene glycol, 5g of anhydrous zinc acetate, and 200g of activated carbon and add them to an argon-protected high-pressure reactor. Stir the mixture, seal the reactor, heat it to 220℃, maintain the reactor pressure at 0.18MPa, and keep it at this temperature for 3 hours. Cool the reactor to 80℃, add 5L of ethylene glycol to dilute the mixture, and filter it. Transfer the filtrate to a clean reactor and stir. Add 15L of 1wt% sodium dodecyl sulfate solution to the filtrate, stir and disperse for 30 minutes, filter it, wash the filter cake three times with purified water, and then transfer it to a drying oven at 60℃ and dry it to constant weight to obtain BHET. In the reaction, ethylene glycol molecules nucleophilically attack the ester bonds in waste PET molecules, breaking the polymer chains to generate bis(2-hydroxyethyl) terephthalate (BHET) and a small amount of oligomers. Activated carbon in the reaction system adsorbs degradation products and impurities, keeping the reaction system clean. Subsequent washing with sodium dodecyl sulfate solution effectively removes metal residues and pigments, improves monomer purity, and yields BHET with uniform molecular structure, low impurity content, and transparent color, providing a stable reaction basis for subsequent repolymerization.

[0023] Weigh out 500g of BHET, 100g of ethylene glycol, 150g of 2-(aminomethyl)propane-1,3-diol, and 5g of anhydrous zinc acetate and add them to an argon-protected polymerization reactor. Stir the reactor and heat it to 140℃. Hold the temperature for 25 minutes. Add 5g of tetrabutyl titanate to the reactor and heat it to 190℃. Hold the temperature for 3 hours. Vacuum the reactor to -0.1MPa and continue heating it to 250℃. Stir and hold the temperature for 50 minutes. Extrude and granulate to obtain recycled PET.

[0024] The reaction was carried out under a dual-catalyst system of tetrabutyl titanate and zinc acetate, and went through two stages: heated polymerization and high-vacuum de-alcoholization. First, the hydroxyl groups of BHET condensed with the residual carboxyl groups to form new ester bonds, while releasing ethylene glycol molecules. In addition, the added 2-(aminomethyl)propane-1,3-diol, besides its hydroxyl group participating in polyesterification, had its amino group partially retained on the side group in the system, thereby introducing reactive amine groups into the polymer backbone. This allowed the recycled PET segments to maintain the rigidity of the polyester backbone while forming amino modifications on the recycled PET molecular chain, improving the chemical activity of the recycled PET and providing binding sites for subsequent chemical reactions.

[0025] The amino-terminal groups of the recycled PET obtained can undergo ring-opening reactions with the epoxy groups in epoxy-modified polysiloxanes to form covalent bonds, or form hydrogen bonds or amide bonds with the carbonyl groups or residual isocyanate groups of polyurethane elastomers, thereby significantly enhancing the interfacial bonding force and forming a more uniform interfacial layer structure. Under external force, this interfacial layer can bear stress transmission and participate in energy dissipation, thereby improving the impact resistance and flexural strength of the material. In addition, since the recycled PET with activated amino-terminal groups can form a denser interfacial bond with the toughening phase, the difference in refractive index at the phase boundary is reduced, thereby reducing light scattering at the phase interface, increasing light transmittance and reducing haze.

[0026] Step 2: Preparation of epoxy-modified polysiloxane Weigh out 800g of octamethylcyclotetrasiloxane, 400g of tetramethyltetraphenylcyclotetrasiloxane, 400g of 3-glycidyl etheroxypropylmethyldiethoxysilane, 50g of tetrabutyl titanate, and 20mL of deionized water and add them to a reaction vessel. Stir the reaction vessel and heat it to 85℃. Keep the reaction vessel at this temperature for 60min. Add 20g of 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane to the reaction vessel and keep the reaction vessel at this temperature for 120min. Cool the reaction vessel to room temperature and add 1L of anhydrous ethanol to the reaction system. Stir and disperse for 20min. Let the mixture stand and separate the liquids. Wash the oily substance twice with purified water and transfer it to a rotary evaporator with a water bath temperature of 70℃. Evacuate the mixture to -0.1MPa and remove low-boiling substances under reduced pressure to obtain epoxy-modified polysiloxane.

[0027] In the reaction, cyclic siloxanes, mainly octamethylcyclotetrasiloxane and tetramethyltetraphenylcyclotetrasiloxane, undergo ring-opening rearrangement polymerization under the action of a catalyst to generate a polysiloxane backbone with a linear structure. At the same time, 3-glycidyl etheroxypropylmethyldiethoxysilane participates in the reaction, introducing epoxy groups into the molecular chain ends or side groups, and 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane acts as a capping agent to cap the polysiloxane chain, forming an epoxy-modified polysiloxane with a hydroxyl-capped Si-O-Si structure in the backbone and epoxy functional groups in the side chains.

[0028] Tetramethyltetraphenylcyclotetrasiloxane introduces a large number of phenyl groups into the molecular chain of epoxy-modified polysiloxanes. On the one hand, this increases the refractive index of the polysiloxane segments, enhancing their optical compatibility with the PET matrix, thereby reducing interfacial light scattering and improving light transmittance in the final composite material. On the other hand, the phenyl structure increases the rigidity of the molecular chain, making the modified polysiloxane not only flexible but also capable of participating in stress bearing to a certain extent, thus improving interfacial mechanical stability. Structurally, the silicon-oxygen bonds in the main chain of the epoxy-modified polysiloxane endow the molecule with excellent flexibility and low modulus, while the epoxy groups at the ends or side chains of the molecule enhance... These epoxy groups provide abundant reactive sites, which can undergo ring-opening addition reactions with hydroxyl or amino groups in amino-modified recycled PET and polyurethane elastomers in subsequent compounding steps to generate covalent or hydrogen bond networks. This allows the flexible siloxane phase to form stable crosslinks with the rigid polyester phase, significantly improving the compatibility and interfacial bonding between the two phases. This makes the material less prone to interfacial delamination under bending loads, thus maintaining high bending strength. Furthermore, as a flexible segment, the epoxy-modified polysiloxane can effectively disperse and alleviate impact loads when subjected to impact, resulting in a significant improvement in the notched impact strength of the simply supported beam.

[0029] Step 3: Preparation of polyurethane elastomer Weigh out 300g of BHET and 1500mL of toluene and add them to an argon-protected reactor. Stir the mixture and heat it to 70℃. Keep the mixture at this temperature and stir until the system is dissolved. Add isophorone diisocyanate to the reactor and keep it at this temperature for 30min. Add 90g of epoxy-modified polysiloxane to the reactor and keep it at this temperature for 2h. Add 20g of 2-hydroxymethyl-1,3-propanediol to the reactor and keep it at this temperature for 40min. Heat the reactor to 80℃ and evacuate it to -0.1MPa. Remove low-boiling-point substances by vacuum distillation to obtain polyurethane elastomer. The amount of isophorone diisocyanate used is 0.55 times the total molar amount of hydroxyl groups in BHET and epoxy-modified polysiloxane.

[0030] In the reaction, BHET undergoes an addition reaction with isophorone diisocyanate to form urethane bonds, forming a polyurethane prepolymer. Subsequently, the introduced epoxy-modified polysiloxane molecule can continue to react and intercalate with the isocyanate groups on the polyurethane prepolymer molecular chain, causing the epoxy-modified polysiloxane and the polyurethane prepolymer chain to copolymerize and form a polyurethane co-intercalation chain. The introduced 2-hydroxymethyl-1,3-propanediol acts as a chain extender, reacting with the isocyanate on the polyurethane co-intercalation chain to increase the degree of crosslinking between polyurethane segments, thus preparing a polyurethane elastomer.

[0031] The hard segments of polyurethane elastomers are composed of urethane structures formed by the reaction of isophorone diisocyanate and BHET, which endow the material with high mechanical strength and heat resistance. The soft segments are derived from the siloxane segments of epoxy-modified polysiloxanes, providing excellent flexibility, elasticity, and energy absorption properties. The flexible siloxane segments in its molecular structure can effectively absorb and disperse energy during impact, preventing rapid crack propagation and significantly improving the notched impact strength of the simply supported beam. There is a strong polar interaction between the urethane structure of the hard segments and the ester chains of recycled PET, which can enhance interfacial bonding through hydrogen bonding or dipole interactions, enabling the two phases to form a stable interpenetrating network, thereby improving the overall flexural strength and dimensional stability.

[0032] Step 4: Preparation of activated silica Weigh out 50g of nano-silica, 18g of γ-aminopropyltriethoxysilane, and 500mL of anhydrous ethanol and add them to a reaction flask. Mix and ultrasonically disperse for 40min. Fix the reaction flask on an iron stand with mechanical stirring. Add 100mL of 3mol / L sodium hydroxide solution to the reaction system. Heat the reaction flask to 50℃ and keep it at that temperature for 40min. Cool the reaction flask to room temperature, filter, wash the filter cake with purified water until neutral, and then dry it. Transfer the filter cake to a drying oven at 60℃ and dry it to constant weight to obtain activated silica.

[0033] In the reaction, γ-aminopropyltriethoxysilane undergoes alkaline-catalyzed hydrolysis in an ethanol / alkaline water system to generate a silane intermediate containing silanol. Then, the silanol condenses with the hydroxyl groups on the surface of nano-silica to form covalent bonds, forming amino-modified activated silica coated with polysiloxane on the outside of the nano-silica particles.

[0034] The amino groups modified on the activated silica can undergo ring-opening addition with the epoxy groups of the epoxy-modified polysiloxane obtained in step 2, and can also form covalent bonds, hydrogen bonds or strong polar interactions with the carbonyl / hydroxyl groups of the aminated recycled PET in step 1 and the polyurethane segments in step 3. Thus, the interface between the inorganic particles and the organic matrix is ​​"stitched" at the microscopic level, which significantly improves the stress transfer efficiency and interfacial peeling resistance. Moreover, after activation by γ-aminopropyltriethoxysilane, the surface energy of the nano silica is reduced, which improves the wettability and rheological stability of the activated silica particles in the melt and makes them easier to disperse. In the reaction system, activated silica acts as a "nano-reinforcing point" to enhance local constraint, improve bending load-bearing capacity and dimensional stability. On the other hand, the interfacial network formed by chemical coupling can achieve multi-level energy dissipation under impact load. Combined with the deformation energy absorption mechanism of the siloxane / polyurethane flexible phase, the notched impact strength is stably improved. Furthermore, activated silica acts as a heterogeneous nucleating agent in the PET melt, promoting rapid, uniform and fine crystallization during the cooling stage. Grain refinement means a reduction in spherulite spacing and a decrease in the non-uniformity of refractive index between crystalline and amorphous regions, further improving the light transmittance of the material.

[0035] Step 5: Prepare cosmetic bottle materials Antioxidant BHT, lubricant polyethylene wax, nucleating agent NP-508, and fluorescent whitening agent OB-1 were mixed evenly in a weight ratio of 6:5:3:2:0.1 to obtain auxiliary additives; Weigh out the following by weight: 70 parts recycled PET, 30 parts polyurethane elastomer, and 5 parts activated silica. Place them in a drying oven and dry until the moisture content is below 50 ppm. After drying, mix them evenly with 2 parts of auxiliary additives and add them to a twin-screw extruder. Set the temperature of the twin-screw extruder to 240℃ in zone I, 250℃ in zone II, 250℃ in zone III, and 260℃ in zone IV. The spindle speed of the twin-screw extruder is 60 rpm. After melting and mixing for 30 seconds, extrude the mixture at an injection pressure of 90 MPa into a mold at a temperature of 10℃. Increase the mold pressure to 60 MPa, hold the pressure for 8 seconds, cool with water for 15 seconds, and then discharge the material to obtain a cosmetic bottle material with a wall thickness of 3 mm.

[0036] By strictly drying recycled PET, polyurethane elastomer, and activated silica, the moisture content of the raw materials is controlled to be below 50 ppm. This prevents hydrolytic degradation or bubble formation during melt blending in a twin-screw extruder. The strong shear provided by the twin-screw extruder refines the polyurethane elastomer and epoxy-modified polysiloxane into submicron-level flexible phase domains, while simultaneously allowing the amino-containing activated silica to achieve uniform dispersion. During melt blending, the short residence time inhibits main chain degradation, and the active functional groups on the recycled PET chains or activated silica can form in-situ bonds with epoxy groups, improving interphase stress transfer efficiency and phase morphology stability. Among the auxiliary additives, the antioxidant BHT inhibits thermo-oxidative aging and yellowing, maintaining molecular weight and color. Polyethylene wax reduces melt interface friction, improves flow, filling, and inorganic particle wetting, and reduces weld line fragility. NP-508, as a nucleating agent, works synergistically with activated silica to significantly increase heterogeneous nucleation density, enabling PET to form fine and uniform grains during subsequent cooling. OB-1 improves appearance clarity through optical whitening and micro-absorption compensation.

[0037] Example 2 This embodiment provides a method for preparing high-impact cosmetic bottle materials from recycled PET, specifically including the following steps: Step 1: Preparation of recycled PET Waste PET is crushed into PET powder with a particle size of 2-5mm; Weigh out 1000g of PET powder, 8.5L of ethylene glycol, 5g of anhydrous zinc acetate, and 250g of activated carbon and add them to an argon-protected high-pressure reactor. Stir the mixture, seal the reactor, and heat it to 225℃. Maintain the reactor pressure at 0.20MPa and keep it at this temperature for 3.5h. Cool the reactor to 85℃, add 5L of ethylene glycol to dilute the mixture, and filter it. Transfer the filtrate to a clean reactor and stir. Add 15L of 1wt% sodium dodecyl sulfate solution to the filtrate, stir and disperse for 40min, filter, wash the filter cake three times with purified water, and then transfer it to a drying oven at 65℃ and dry it to constant weight to obtain BHET. Weigh out 500g of BHET, 100g of ethylene glycol, 175g of 2-(aminomethyl)propane-1,3-diol, and 5g of anhydrous zinc acetate and add them to an argon-protected polymerization reactor. Stir the reactor and heat it to 150°C. Hold the temperature for 30 minutes. Add 5g of tetrabutyl titanate to the reactor and heat it to 195°C. Hold the temperature for 3.5 hours. Vacuum the reactor to -0.1MPa and continue heating it to 250°C. Stir and hold the temperature for 60 minutes. Extrude and granulate to obtain recycled PET.

[0038] Step 2: Preparation of epoxy-modified polysiloxane Weigh out 800g of octamethylcyclotetrasiloxane, 450g of tetramethyltetraphenylcyclotetrasiloxane, 400g of 3-glycidyl etheroxypropylmethyldiethoxysilane, 50g of tetrabutyl titanate, and 20mL of deionized water and add them to a reaction vessel. Stir the reaction vessel and heat it to 90℃. Keep the temperature for 70min. Add 20g of 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane to the reaction vessel and keep the temperature for 135min. Cool the reaction vessel to room temperature and add 1L of anhydrous ethanol to the reaction system. Stir and disperse for 25min. Let it stand and separate the liquids. Wash the oily substance twice with purified water and transfer it to a rotary evaporator with a water bath temperature of 75℃. Evacuate the system to -0.1MPa and remove low-boiling substances by vacuum evaporation to obtain epoxy-modified polysiloxane.

[0039] Step 3: Preparation of polyurethane elastomer Weigh out 300g of BHET and 1500mL of toluene and add them to an argon-protected reactor. Stir the reactor and heat it to 75°C. Keep stirring until the system is dissolved. Add isophorone diisocyanate to the reactor and keep it at this temperature for 40min. Add 105g of epoxy-modified polysiloxane to the reactor and keep it at this temperature for 2.5h. Add 20g of 2-hydroxymethyl-1,3-propanediol to the reactor and keep it at this temperature for 50min. Heat the reactor to 85°C and evacuate it to -0.1MPa. Remove low-boiling-point substances by vacuum distillation to obtain polyurethane elastomer. The amount of isophorone diisocyanate used is 0.55 times the total molar amount of hydroxyl groups in BHET and epoxy-modified polysiloxane.

[0040] Step 4: Preparation of activated silica Weigh out 50g of nano-silica, 19.5g of γ-aminopropyltriethoxysilane, and 500mL of anhydrous ethanol and add them to a reaction flask. Mix and sonicate for 45min. Fix the reaction flask on an iron stand with mechanical stirring. Add 100mL of 4mol / L sodium hydroxide solution to the reaction system. Heat the reaction flask to 55℃ and keep it at that temperature for 45min. Cool the reaction flask to room temperature and filter. Wash the filter cake with purified water until neutral and then dry it. Transfer the filter cake to a drying oven at 65℃ and dry it to constant weight to obtain activated silica.

[0041] Step 5: Prepare cosmetic bottle materials Antioxidant BHT, lubricant polyethylene wax, nucleating agent NP-508, and fluorescent whitening agent OB-1 were mixed evenly in a weight ratio of 6:5:3:2:0.1 to obtain auxiliary additives; Weigh out 75 parts by weight of recycled PET, 33 parts by weight of polyurethane elastomer, and 6 parts by weight of activated silica. Place them in a drying oven and dry until the moisture content is below 50 ppm. After drying, mix them evenly with 2.5 parts of auxiliary additives and add them to a twin-screw extruder. Set the temperature of the twin-screw extruder to 245℃ in zone I, 255℃ in zone II, 255℃ in zone III, and 265℃ in zone IV. The spindle speed of the twin-screw extruder is 70 rpm. After melting and mixing for 40 seconds, extrude the mixture at an injection pressure of 95 MPa into a mold at a temperature of 13℃. Increase the mold pressure to 70 MPa, hold the pressure for 10 seconds, cool with water for 17 seconds, and then discharge the material to obtain a cosmetic bottle material with a wall thickness of 3.5 mm.

[0042] Example 3 This embodiment provides a method for preparing high-impact cosmetic bottle materials from recycled PET, specifically including the following steps: Step 1: Preparation of recycled PET Waste PET is crushed into PET powder with a particle size of 2-5mm; Weigh 1000g of PET powder, 9L of ethylene glycol, 5g of anhydrous zinc acetate, and 300g of activated carbon and add them to an argon-protected high-pressure reactor. Stir the mixture, seal the reactor, raise the temperature to 230℃, maintain the reactor pressure at 0.22MPa, and keep the reaction at this temperature for 4 hours. Then, cool the reactor to 90℃, add 5L of ethylene glycol to dilute the mixture, and filter it. Transfer the filtrate to a clean reactor and stir. Add 15L of 1wt% sodium dodecyl sulfate solution to the filtrate, stir and disperse for 50 minutes, filter, wash the filter cake three times with purified water, and then transfer it to a drying oven at 70℃ and dry it to constant weight to obtain BHET. Weigh out 500g of BHET, 100g of ethylene glycol, 200g of 2-(aminomethyl)propane-1,3-diol, and 5g of anhydrous zinc acetate and add them to an argon-protected polymerization reactor. Stir the reactor and heat it to 160℃. Hold the temperature for 35 minutes. Add 5g of tetrabutyl titanate to the reactor and heat it to 200℃. Hold the temperature for 4 hours. Vacuum the reactor to -0.1MPa and continue heating it to 250℃. Stir and hold the temperature for 70 minutes. Extrude and granulate to obtain recycled PET.

[0043] Step 2: Preparation of epoxy-modified polysiloxane Weigh out 800g of octamethylcyclotetrasiloxane, 500g of tetramethyltetraphenylcyclotetrasiloxane, 400g of 3-glycidyl etheroxypropylmethyldiethoxysilane, 50g of tetrabutyl titanate, and 20mL of deionized water and add them to a reaction vessel. Stir the reaction vessel and heat it to 95℃. Keep the reaction vessel at this temperature for 80min. Add 20g of 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane to the reaction vessel and keep the reaction vessel at this temperature for 150min. Cool the reaction vessel to room temperature and add 1L of anhydrous ethanol to the reaction system. Stir and disperse for 30min. Let the mixture stand and separate the liquids. Wash the oily substance twice with purified water and transfer it to a rotary evaporator with a water bath temperature of 80℃. Evacuate the mixture to -0.1MPa and remove low-boiling substances by vacuum evaporation to obtain epoxy-modified polysiloxane.

[0044] Step 3: Preparation of polyurethane elastomer Weigh out 300g of BHET and 1500mL of toluene and add them to an argon-protected reactor. Stir the reactor and heat it to 80℃. Keep the temperature and stir until the system is dissolved. Add isophorone diisocyanate to the reactor and keep it at the temperature for 50min. Add 120g of epoxy-modified polysiloxane to the reactor and keep it at the temperature for 3h. Add 20g of 2-hydroxymethyl-1,3-propanediol to the reactor and keep it at the temperature for 60min. Heat the reactor to 90℃ and evacuate it to -0.1MPa. Remove low-boiling-point substances by vacuum distillation to obtain polyurethane elastomer. The amount of isophorone diisocyanate is 0.55 times the total molar amount of hydroxyl groups in BHET and epoxy-modified polysiloxane.

[0045] Step 4: Preparation of activated silica Weigh out 50g of nano-silica, 21g of γ-aminopropyltriethoxysilane, and 500mL of anhydrous ethanol and add them to a reaction flask. Mix and sonicate for 50min. Fix the reaction flask on an iron stand with mechanical stirring. Add 100mL of 5mol / L sodium hydroxide solution to the reaction system. Heat the reaction flask to 60℃ and keep it at that temperature for 50min. Cool the reaction flask to room temperature and filter. Wash the filter cake with purified water until neutral and then dry it. Transfer the filter cake to a drying oven at 70℃ and dry it to constant weight to obtain activated silica.

[0046] Step 5: Prepare cosmetic bottle materials Antioxidant BHT, lubricant polyethylene wax, nucleating agent NP-508, and fluorescent whitening agent OB-1 were mixed evenly in a weight ratio of 6:5:3:2:0.1 to obtain auxiliary additives; Weigh out the following by weight: 80 parts recycled PET, 36 parts polyurethane elastomer, and 7 parts activated silica. Place them in a drying oven and dry until the moisture content is below 50 ppm. After drying, mix them evenly with 3 parts of auxiliary additives and add them to a twin-screw extruder. Set the temperature of the twin-screw extruder to 250℃ in zone I, 260℃ in zone II, 260℃ in zone III, and 270℃ in zone IV. The spindle speed of the twin-screw extruder is 80 rpm. After melting and mixing for 50 seconds, extrude the mixture at an injection pressure of 100 MPa into a mold at a temperature of 15℃. Increase the mold pressure to 80 MPa, hold the pressure for 12 seconds, cool with water for 20 seconds, and then discharge the material to obtain a cosmetic bottle material with a wall thickness of 4 mm.

[0047] Comparative Example 1 The difference between this comparative example and Example 3 is that, in step 1, 2-(aminomethyl)propane-1,3-diol is replaced with an equimolar amount of ethylene glycol.

[0048] Comparative Example 2 The difference between this comparative example and Example 3 is that tetramethyltetraphenylcyclotetrasiloxane was not added in step 2.

[0049] Comparative Example 3 The difference between this comparative example and Example 3 is that step 2 is omitted, and epoxy-modified polysiloxane is not added in step 3.

[0050] Comparative Example 4 The difference between this comparative example and Example 3 is that step 4 is omitted, and the activated silica in step 5 is replaced with nano silica in step 4.

[0051] Performance testing: The notched impact strength of the cosmetic bottle material samples prepared in Examples 1-3 and Comparative Examples 1-4 was determined in accordance with the standard GB / T 1043.1-2008 "Determination of impact properties of simply supported beam plastics - Part 1: Non-instrumental impact test". The light transmittance and haze of the cosmetic bottle material samples prepared in Examples 1-3 and Comparative Examples 1-4 were determined in accordance with the standard GB / T 2410-2008 "Determination of transmittance and haze of transparent plastics". The bending stress of the cosmetic bottle material samples prepared in Examples 1-3 and Comparative Examples 1-4 was determined according to the standard GB / T 9341-2008 "Determination of Bending Properties of Plastics" at a test rate of 1 mm / min. The specific test data is shown in Table 1 below.

[0052] Data Analysis: Comparative analysis of the data in Table 1 shows that the flexural stress of the cosmetic bottle material prepared by this invention reaches 68-75 MPa, and the notched impact strength of a simply supported beam reaches 22-24 kJ / m. 2 The light transmittance reaches 89-92%, and the haze reaches 4.7-5.2%. The test data of the same thickness sample are better than those of the comparative example. This shows that the present invention uses waste PET as raw material, and obtains reactive recycled PET through depolymerization, ammoniation and repolymerization. The recycled PET is reinforced by epoxy-modified polysiloxane-integrated polyurethane elastomer and γ-aminopropyltriethoxysilane-activated nano-silica. After twin-screw melt blending and rapid cooling molding, it not only effectively improves the bending stress and impact resistance of cosmetic bottle material, but also improves the transparency of cosmetic bottle material, realizing the high-value application of waste PET recycled material in the field of high-end cosmetic packaging.

[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," and "specific example" 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 method for preparing high-impact cosmetic bottle material from recycled PET, characterized in that, Includes the following steps: S1. The waste PET is crushed into PET powder with a particle size of 2-5mm, and then the PET powder is regenerated by alcoholysis to obtain BHET; S2. Add BHET, ethylene glycol, 2-(aminomethyl)propane-1,3-diol and anhydrous zinc acetate to a polymerization reactor under an inert gas atmosphere and stir. Heat the polymerization reactor to 140-160℃ and hold for 25-35 min. Add tetrabutyl titanate to the polymerization reactor. Heat the polymerization reactor to 190-200℃ and hold for 3-4 h. Vacuum the polymerization reactor to -0.1 MPa. Continue to heat the reactor to 250℃ and stir for 50-70 min. Extrude and granulate to obtain recycled PET. S3. After drying recycled PET, polyurethane elastomer, activated silica, and auxiliary additives, mix them evenly in a twin-screw extruder and melt-mix for 30-50 seconds. Then, extrude and inject the mixture into the mold, hold the pressure for 8-12 seconds, cool for 15-20 seconds, and discharge the material to obtain cosmetic bottle material with a wall thickness of 3-4 mm.

2. The method for preparing high-impact cosmetic bottle material from recycled PET according to claim 1, characterized in that, In step S1, the preparation method of BHET is as follows: PET powder, ethylene glycol, anhydrous zinc acetate and activated carbon are added to a high-pressure reactor under an inert gas atmosphere and stirred. After the reactor is sealed, the temperature is raised to 220-230℃, the pressure of the reactor is maintained at 0.18-0.22MPa, and the reaction is carried out for 3-4 hours. After post-processing, BHET is obtained.

3. The method for preparing high-impact cosmetic bottle material from recycled PET according to claim 2, characterized in that, The ratio of PET powder, ethylene glycol, anhydrous zinc acetate, and activated carbon is 1g:8-9mL:0.005g:0.2-0.3g.

4. The method for preparing high-impact cosmetic bottle material from recycled PET according to claim 1, characterized in that, In step S2, the weight ratio of BHET, ethylene glycol, 2-(aminomethyl)propane-1,3-diol, anhydrous zinc acetate, and tetrabutyl titanate is 10:2:3-4:0.1:0.

1.

5. The method for preparing high-impact cosmetic bottle material from recycled PET according to claim 1, characterized in that, In step S3, the weight ratio of recycled PET, polyurethane elastomer, activated silica, and auxiliary additives is 70-80:30-36:5-7:2-3. The auxiliary additives consist of antioxidant, lubricant, nucleating agent, and fluorescent whitening agent in a weight ratio of 6:5:3:2:0.

1. The antioxidant is BHT, the lubricant is polyethylene wax, the nucleating agent is NP-508, and the fluorescent whitening agent is OB-1. The temperatures of the twin-screw extruder are 240-250℃ in zone I, 250-260℃ in zone II, 250-260℃ in zone III, and 260-270℃ in zone IV. The spindle speed of the twin-screw extruder is 60-80 rpm. The extrusion injection pressure is 90-100 MPa. The die temperature is 10-15℃, and the die holding pressure is 60-80 MPa.

6. The method for preparing high-impact cosmetic bottle material from recycled PET according to claim 1, characterized in that, The preparation method of polyurethane elastomer is as follows: Under the protection of an inert gas atmosphere, BHET and toluene are mixed, the reaction system is heated to 70-80℃, and stirred until the system is dissolved. Isophorone diisocyanate is added to the reaction system, and the reaction is maintained for 30-50 min. Epoxy-modified polysiloxane is added to the reaction system, and the reaction is maintained for 2-3 h. 2-Hydroxymethyl-1,3-propanediol is added to the reaction system, and the reaction is maintained for 40-60 min. After post-treatment, polyurethane elastomer is obtained.

7. The method for preparing high-impact cosmetic bottle material from recycled PET according to claim 6, characterized in that, The ratio of BHET, toluene, epoxy-modified polysiloxane, and 2-hydroxymethyl-1,3-propanediol is 10g:50mL:3-4g:0.2g, and the amount of isophorone diisocyanate is 0.55 times the total molar amount of hydroxyl groups in BHET and epoxy-modified polysiloxane.

8. The method for preparing high-impact cosmetic bottle material from recycled PET according to claim 6, characterized in that, The preparation method of epoxy-modified polysiloxane is as follows: octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, 3-glycidyl etheroxypropylmethyldiethoxysilane, n-butyl titanate and deionized water are mixed, the reaction system is heated to 85-95℃ and kept at this temperature for 60-80 min, 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane is added to the reaction system, and after post-treatment, epoxy-modified polysiloxane is obtained.

9. A method for preparing high-impact cosmetic bottle material from recycled PET according to claim 8, characterized in that, The ratio of octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, 3-glycidyl etheroxypropylmethyldiethoxysilane, 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane, n-butyl titanate, and deionized water is 8g:4-5g:4g:2g:0.5g:0.2mL.

10. The method for preparing high-impact cosmetic bottle material from recycled PET according to claim 1, characterized in that, The preparation method of activated silica is as follows: nano silica, γ-aminopropyltriethoxysilane and anhydrous ethanol are mixed and ultrasonically dispersed for 40-50 min. Alkali solution is added to the reaction system and the reaction is kept at a certain temperature for 40-50 min. After post-treatment, activated silica is obtained.

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