Anti-impact glasses frame preparation process based on nanometer strengthening structure

Abstract

The invention relates to the technical field of glasses manufacturing, and discloses an anti-impact glasses frame preparation process based on a nano reinforced structure, which comprises the following steps: S1, carrying out melt blending granulation on polycarbonate, thermoplastic polyurethane and nano ceramic particles pretreated by a silane coupling agent KH-560 under the conditions that the temperature is 190-210 DEG C and the rotating speed of a screw is 200-250 r / min to obtain nano reinforced master batches; s2, through a three-layer co-extrusion process, a composite profile with an outer pure PC layer, a middle nano reinforced master batch layer and an inner TPU elastic layer is formed; s3, a micro-nano structure strengthening interface is etched on the surface of the profile through femtosecond laser; s4, performing segmented hot pressing and applying prestress to eliminate stress; and S5, carrying out heat preservation, cooling and forming through a gradient temperature control furnace. The three-layer structural design of PC outer layer rigid supporting, nano ceramic middle layer load dispersing and TPU inner layer buffering and energy absorbing is adopted, micro-nano surface strengthening is matched, the impact strength of the glasses frame is improved, the adhesive force of the coating is further enhanced, and personalized color spraying and anti-fog function integration can be achieved.

Description

Technical Field

[0001] This invention relates to the field of eyeglasses manufacturing technology, specifically to a process for preparing impact-resistant eyeglass frames based on nano-reinforced structures. Background Technology

[0002] In the fields of modern consumer electronics and fashion accessories, the functional requirements for eyeglass frames have expanded from simple vision correction to safety protection and personalized design. Impact-resistant eyeglass frames are widely used in sports protection, industrial operations, outdoor adventures, and other scenarios, and their performance directly affects the user's safety and experience. For example, in extreme sports, high-quality impact-resistant eyeglass frames can withstand the impact of high-speed flying debris, protecting the eyes; in industrial environments, they can effectively prevent mechanical collisions from causing injury to the wearer.

[0003] Currently, existing manufacturing processes for impact-resistant eyeglass frames have significant drawbacks. On the one hand, traditional processes use a single polymer material (such as ordinary PC plastic), which, while possessing a certain degree of toughness, is prone to stress concentration and fracture under impact loads. Furthermore, the material's high density results in poor long-term wearing comfort. On the other hand, conventional nano-reinforcement processes involve only simple physical blending of nanoparticles, leading to insufficient dispersion uniformity and a tendency to form agglomerates. This limits the improvement in the material's mechanical properties, and the nanoparticles can easily clog mold channels during molding, reducing production efficiency. In addition, traditional surface treatment processes struggle to form a uniform reinforcing layer on complex curved surfaces, resulting in significant differences in impact resistance across different parts of the eyeglass frame.

[0004] Therefore, developing a manufacturing process that combines high impact resistance, lightweight, and uniform reinforcement is an urgent practical need to improve the overall performance and market competitiveness of eyeglass frames. Summary of the Invention

[0005] The purpose of this invention is to provide a process for manufacturing impact-resistant eyeglass frames based on nano-reinforced structures in order to solve the above-mentioned problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A process for manufacturing impact-resistant eyeglass frames based on nano-reinforced structures includes the following steps:

[0008] S1: Polycarbonate, thermoplastic polyurethane and nano-ceramic particles are fed into a twin-screw extruder and melt-blended at 190-210℃ with a screw speed of 200-250 r / min. The mixture is then extruded and granulated to obtain nano-reinforced masterbatch. The surface of the nano-ceramic particles is pretreated with silane coupling agent KH-560.

[0009] S2: It adopts a three-layer co-extrusion process, with an outer layer of pure PC, a middle layer of nano-reinforced masterbatch, and an inner layer of TPU elasticity to form a composite profile;

[0010] S3: Fix the composite profile to a rotating fixture and use a femtosecond laser processing system to etch a micron-level pit array and a nano-level protrusion structure on the surface to form a micro-nano dual-strength interface;

[0011] S4: Place the processed profile into the mold and use a segmented hot pressing process. At the same time, apply radial prestress to eliminate internal stress concentration.

[0012] S5: Place the molded eyeglass frame in a gradient temperature control furnace to form a temperature gradient field, and then cool it to room temperature with the furnace after holding it at that temperature.

[0013] Preferably, the nano-ceramic particles have a particle size of 20-50 nm, an Al2O3 content of ≥99.5%, a silane coupling agent KH-560 treatment solution concentration of 3-5 wt%, an ultrasonic dispersion time of 15-20 min, and a silane coupling agent solution pH of 4.5-5.5.

[0014] Preferably, the thickness of the pure PC layer is 0.3-0.5 mm, the thickness of the nano-reinforced masterbatch layer is 0.8-1.2 mm, and the thickness of the TPU elastic layer is 0.2-0.4 mm; the extrusion temperature is controlled as follows: feeding section 180-190℃, melting section 210-230℃, die section 200-220℃, traction speed 1.5-2.5 m / min, and the melt pressure of each layer is as follows: outer PC layer 8-12 MPa, middle nano-reinforced layer 15-20 MPa, and inner TPU layer 5-8 MPa.

[0015] Preferably, the diameter of the micron-scale pit array is 50-100 μm and the depth is 20-30 μm; the height of the nanoscale protrusion structure is 50-80 nm and the density is 10^6-10^7 pieces / cm²; the femtosecond laser processing system has a wavelength of 800 nm, a pulse width of 50 fs, a power of 10-20 W, a processing speed of 50-100 mm / s, and a scanning interval of 20-50 μm.

[0016] Preferably, in the segmented hot pressing process, the mold temperature is 85-95℃, the pressure is 5-8MPa, the temperature is first raised to 110-130℃ at 3-5℃ / min, the pressure is held for 10-15min, and then the temperature is lowered to 60-70℃ at 2-3℃ / min, the radial prestress is 0.5-1.0MPa, and the surface roughness Ra of the mold cavity is ≤0.8μm.

[0017] Preferably, the gradient temperature control furnace has a heating rate of 5-8℃ / min, an outer layer temperature of 120-140℃, an inner layer temperature of 80-100℃, a temperature gradient of 40-60℃, and a holding time of 2-3h.

[0018] Preferably, the mass ratio of polycarbonate, thermoplastic polyurethane and nano-ceramic particles in the nano-reinforced masterbatch is 7:2:1.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0020] 1. This invention adopts a three-layer structure design with a rigid PC outer layer, a load-dispersing nano-ceramic middle layer, and a buffering and energy-absorbing TPU inner layer, combined with micro-nano surface strengthening, to improve the impact strength of the eyeglass frame and enhance the coating adhesion, enabling personalized color spraying and anti-fog function integration.

[0021] 2. This invention uses a nanoparticle surface pretreatment process to solve the agglomeration problem, increases the extrusion speed, shortens the production cycle, and the gradient aging process improves the product yield. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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.

[0023] Example 1

[0024] Raw material preparation

[0025] PC (brand name L-1250Y), TPU (Shore hardness 85A), nano Al2O3 particles (particle size 30nm), silane coupling agent KH-560.

[0026] Preparation process

[0027] Preparation of nano-reinforced masterbatch: 70g PC, 20g TPU, and 10g nano Al2O3 particles were fed into a twin-screw extruder. The nanoparticles were pre-treated with 4wt% KH-560 ethanol solution (pH=5.0) by ultrasonic treatment for 18min. The extrusion temperature was 195℃ and the screw speed was 220r / min to obtain the masterbatch.

[0028] Multilayer co-extrusion: outer PC layer thickness 0.4mm, middle masterbatch layer 1.0mm, inner TPU layer 0.3mm. Extrusion temperature: feeding section 185℃, melting section 220℃, die section 210℃, traction speed 2.0m / min, pressure of each layer 10MPa, 18MPa, 6MPa respectively.

[0029] Micro-nano processing: Laser power 15W, speed 80mm / s, spacing 30μm, to process micro-pits with a diameter of 80μm and a depth of 25μm and nano-protrusions with a height of 60nm.

[0030] Hot pressing: mold temperature 90℃, pressure 6MPa, heating rate 4℃ / min to 120℃, holding pressure for 12min, cooling rate 2.5℃ / min to 65℃, apply radial prestress of 0.8MPa.

[0031] Gradient aging: outer layer temperature 130℃, inner layer temperature 90℃, temperature gradient 40℃, heat preservation for 2.5h.

[0032] Example 2

[0033] The difference from Example 1 is that the nanoparticle size is 50nm, the silane concentration is 5wt%, the multilayer co-extrusion traction speed is 1.5m / min, the micro-nano processing power is 10W, the hot pressing pressure is 5MPa, and the gradient aging temperature difference is 50℃.

[0034] Example 3

[0035] The difference from Example 1 is that the nanoparticle size is 20nm, the silane concentration is 3wt%, the multilayer co-extrusion traction speed is 2.5m / min, the micro-nano processing power is 20W, the hot pressing pressure is 8MPa, and the gradient aging temperature difference is 60℃.

[0036] Comparative Example 1 (micro-nano processing omitted)

[0037] The preparation process is the same as in Example 1, but step S3 is omitted, and hot pressing is performed directly.

[0038] Comparative Example 2 (Single-layer PC structure)

[0039] Only pure PC extrusion (1.5mm thickness) is used, and the rest of the process is the same as in Example 1, without the intermediate masterbatch layer and TPU inner layer.

[0040] Comparative Example 3 (Nanoparticles without pretreatment)

[0041] The nanoparticles were directly blended with PC and TPU without silane coupling treatment, and the rest of the process was the same as in Example 1.

[0042] Performance testing

[0043] Testing equipment and standards

[0044] Impact strength test: Drop ball impact tester (compliant with ISO 1621-1 standard), steel ball mass 16g, impact height 1.3m, record the fracture condition.

[0045] Density test: Measured using an electronic density balance (GB / T 1033.1-2008) and the immersion method.

[0046] Surface hardness test: Micro Vickers hardness tester (GB / T 4340.1-2009), load 0.5kg, holding pressure for 15s.

[0047] Coating adhesion test: Cross-cut test (ISO 2409), using a 1mm grid spacing, observe the peeling off after the tape is removed.

[0048] Test Results

[0049] sample Impact strength (J / cm²) Density (g / cm³) Surface hardness (HV) Coating adhesion (rating) Example 1 45.2 1.25 185 Level 0 Example 2 42.8 1.28 178 Level 0 Example 3 46.5 1.23 192 Level 0 Comparative Example 1 28.7 1.25 135 Level 1 Comparative Example 2 22.3 1.20 120 Level 1 Comparative Example 3 31.5 1.26 142 Level 1

[0050] Results Analysis

[0051] The impact strength of Examples 1-3 was significantly higher than that of the comparative example, demonstrating that the synergistic effect of micro-nano processing, multilayer structure and nano pretreatment can effectively improve impact resistance.

[0052] Comparative Example 1, which omitted micro-nano processing, showed a 27% decrease in surface hardness and a reduction in coating adhesion, demonstrating that micro-nano structures are crucial for improving surface properties.

[0053] Comparative Example 2 uses a single-layer PC structure, and its impact strength is only 49% of that of Example 1, verifying the necessity of a multi-layer composite structure.

[0054] Comparative Example 3 showed limited improvement in mechanical properties due to nanoparticle aggregation, demonstrating the crucial role of pretreatment process in achieving uniform dispersion.

[0055] The above description of the embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A manufacturing process for impact-resistant eyeglass frames based on nano-reinforced structures, characterized in that, Includes the following steps: S1: Polycarbonate, thermoplastic polyurethane and nano-ceramic particles are fed into a twin-screw extruder and melt-blended at 190-210℃ with a screw speed of 200-250 r / min. The mixture is then extruded and granulated to obtain nano-reinforced masterbatch. The surface of the nano-ceramic particles is pretreated with silane coupling agent KH-560. S2: It adopts a three-layer co-extrusion process, with an outer layer of pure PC, a middle layer of nano-reinforced masterbatch, and an inner layer of TPU elasticity to form a composite profile; S3: Fix the composite profile to a rotating fixture and use a femtosecond laser processing system to etch a micron-level pit array and a nano-level protrusion structure on the surface to form a micro-nano dual-strength interface; S4: Place the processed profile into the mold and use a segmented hot pressing process. At the same time, apply radial prestress to eliminate internal stress concentration. S5: Place the molded eyeglass frame in a gradient temperature control furnace to form a temperature gradient field, and then cool it to room temperature with the furnace after holding it at that temperature.

2. The manufacturing process for an impact-resistant eyeglass frame based on a nano-reinforced structure according to claim 1, characterized in that, The nano-ceramic particles have a particle size of 20-50 nm, an Al2O3 content of ≥99.5%, a silane coupling agent KH-560 treatment solution concentration of 3-5 wt%, an ultrasonic dispersion time of 15-20 min, and a silane coupling agent solution pH of 4.5-5.

5.

3. The manufacturing process for an impact-resistant eyeglass frame based on a nano-reinforced structure according to claim 1, characterized in that, The thickness of the pure PC layer is 0.3-0.5 mm, the thickness of the nano-reinforced masterbatch layer is 0.8-1.2 mm, and the thickness of the TPU elastic layer is 0.2-0.4 mm. The extrusion temperature is controlled as follows: feeding section 180-190℃, melting section 210-230℃, die section 200-220℃, traction speed 1.5-2.5 m / min, and melt pressure of each layer as follows: outer PC layer 8-12 MPa, middle nano-reinforced layer 15-20 MPa, inner TPU layer 5-8 MPa.

4. The manufacturing process for an impact-resistant eyeglass frame based on a nano-reinforced structure according to claim 1, characterized in that, The micron-scale pit array has a diameter of 50-100 μm and a depth of 20-30 μm; the nanoscale protrusion structure has a height of 50-80 nm and a density of 10^6-10^7 pieces / cm²; the femtosecond laser processing system has a wavelength of 800 nm, a pulse width of 50 fs, a power of 10-20 W, a processing speed of 50-100 mm / s, and a scanning interval of 20-50 μm.

5. The manufacturing process for an impact-resistant eyeglass frame based on a nano-reinforced structure according to claim 1, characterized in that, In the segmented hot pressing process, the mold temperature is 85-95℃, the pressure is 5-8MPa, the temperature is first raised to 110-130℃ at 3-5℃ / min, the pressure is held for 10-15min, and then the temperature is lowered to 60-70℃ at 2-3℃ / min. The radial prestress is 0.5-1.0MPa, and the surface roughness Ra of the mold cavity is ≤0.8μm.

6. The manufacturing process for an impact-resistant eyeglass frame based on a nano-reinforced structure according to claim 1, characterized in that, The gradient temperature control furnace has a heating rate of 5-8℃ / min, an outer layer temperature of 120-140℃, an inner layer temperature of 80-100℃, a temperature gradient of 40-60℃, and a holding time of 2-3h.

7. The manufacturing process for an impact-resistant eyeglass frame based on a nano-reinforced structure according to claim 1, characterized in that, The mass ratio of polycarbonate, thermoplastic polyurethane and nano-ceramic particles in the nano-reinforced masterbatch is 7:2:1.