A lightweight transparent ballistic visor and a method of making the same

Abstract

The application discloses a light transparent bulletproof mask and a preparation method thereof, and relates to the technical field of bulletproof masks. The bulletproof mask comprises an inner layer, an outer layer and an intermediate layer, the inner layer is a first polycarbonate plate, the outer layer is a second polycarbonate plate, the intermediate layer is a high-alumina silicate glass plate and a high-lithium silicate glass plate, the multiple layers are bonded and combined by using a thermoplastic polyurethane adhesive, and after the combination, the first polycarbonate plate, the high-alumina silicate glass plate, the high-lithium silicate glass plate and the second polycarbonate plate are sequentially arranged from inside to outside; and the mask edge is coated with a low-temperature-resistant PUR hot melt adhesive sealing edge. The application solves the common technical problem of the mask that the polyurethane adhesive is hygroscopic and cracks by using a sealing glue process, successfully realizes the maintenance of the tensile maintenance rate of the temperature-resistant PUR hot melt adhesive through a wet mist curing technology, improves the toughness of the temperature-resistant hot melt adhesive, and solves the problem of cracking after the sealing edge is sealed and cured.

Description

Technical Field

[0001] This invention relates to the field of bulletproof face shield technology, specifically to a lightweight transparent bulletproof face shield and its manufacturing method. Background Technology

[0002] Transparent bulletproof face shields are crucial equipment for facial protection while maintaining eye visibility, significantly reducing the damage from shrapnel, projectiles, and explosive fragments. Currently, commercially available Level 2 transparent bulletproof face shields for public security use a composite design of polycarbonate and polymethyl methacrylate. This design results in face shields that are heavy, prone to aging, yellowing, and delamination. Furthermore, the polyurethane or PVB adhesive may brittle and crack at low temperatures (-25°C).

[0003] To address the aforementioned issues, Chinese invention patent CN1349886A discloses a bulletproof face shield. This shield uses a transparent polyurethane adhesive or a polyurethane film as an energy-absorbing layer to composite a polycarbonate inner layer and a smooth glass outer layer. The glass thickness is 3-12mm, the polycarbonate thickness is 3-6mm, and the total shield thickness is 8-20mm. However, this face shield suffers from significant optical distortion, the polycarbonate sheet exhibits defects such as fish-scale patterns and dotted patterns after lamination, the polyurethane adhesive is prone to moisture absorption and cracking, and the bulletproof performance is relatively poor. Chinese utility model patent CN202974051U discloses a bulletproof face shield that uses a high-temperature, high-pressure bonding process to composite a 3-10mm thick PMMA intermediate layer with polycarbonate, which serves as both the inner and outer layers. This achieves structural integrity after impact and allows the face shield to withstand secondary impacts. However, the mask has poor surface hardness and is easily scratched. The use of hardened polycarbonate board composite material results in brittle cracks, and its weather resistance is poor, with significant yellowing problems after exposure to ultraviolet light. Summary of the Invention

[0004] To address the aforementioned issues, this invention discloses a lightweight transparent bulletproof face shield and its preparation method, which has advantages such as light weight, aging resistance, and resistance to yellowing, and can provide Level II public security protection capability in low-temperature environments.

[0005] A lightweight transparent bulletproof face shield according to the present invention comprises an inner layer, an outer layer, and a middle layer. The inner layer is a first polycarbonate sheet. The outer layer is a second polycarbonate sheet. The middle layer comprises a high-alumina silicate glass sheet and a high-lithium silicate glass sheet. The multiple layers are bonded together using a thermoplastic polyurethane adhesive. After bonding, the layers, from the inside out, are the first polycarbonate sheet, the high-alumina silicate glass sheet, the high-lithium silicate glass sheet, and the second polycarbonate sheet. The edges of the face shield are sealed with low-temperature resistant PUR hot melt adhesive. The bulletproof face shield is bent towards the face, and the surface of the first polycarbonate sheet facing the face is sprayed with an anti-fog coating to form an anti-fog coating surface.

[0006] Preferably, the thickness of the first polycarbonate sheet is 5.0-6.0 mm, the thickness of the high-alumina silicate glass sheet is 4.0-8.0 mm, the thickness of the high-lithium silicate glass sheet is 0.5-1.5 mm, the thickness of the second polycarbonate sheet is 0.5-1.5 mm, and the thickness of the thermoplastic polyurethane adhesive is 0.6-1.8 mm; the first and second polycarbonate sheets are the same size, the high-alumina silicate glass sheet and the high-lithium silicate glass sheet are the same size, and the glass sheet is smaller than the polycarbonate sheet, forming a concave structure after lamination, and the low-temperature resistant PUR hot melt adhesive is applied to the concave structure, with the outer surface flush with the outer edge of the polycarbonate sheet.

[0007] The present invention further discloses a method for preparing the above-mentioned lightweight transparent bulletproof face shield, comprising the following steps:

[0008] Step 1: Raw material preparation: First polycarbonate sheet, high aluminosilicate glass sheet, high lithium silicate glass sheet, second polycarbonate sheet, thermoplastic polyurethane adhesive, low-temperature resistant PUR hot melt adhesive;

[0009] Step 2, Raw Material Shaping: The polycarbonate sheet and glass sheet are processed according to the design dimensions, and the required polycarbonate sheet and glass sheet are bent into shape using hot bending process and high-precision fixtures; the polycarbonate sheet after hot bending is shaped using water bath heating, and then dried.

[0010] Step 3, Raw material modification: Harden the outer surface of the second polycarbonate board; chemically strengthen the high-lithium silicate glass board and the high-alumina silicate glass board; spray an anti-fog coating on the inner surface of the first polycarbonate board using a low-temperature baking method.

[0011] Step 4, Composite Process: The raw materials processed in Step 3 are composited using a low-temperature and high-pressure composite method. The composite sequence is as follows: second polycarbonate board, high-lithium silicate glass, high-alumina silicate glass, and first polycarbonate board. Thermoplastic polyurethane adhesive is used as the composite bonding material during the composite process.

[0012] Step 5, Sealing Process: Use low-temperature resistant PUR hot melt adhesive to seal the edges of the laminated mask;

[0013] Step 6, wet fog curing process: Coat the edges of the transparent mask obtained in step 5 with ethylene glycol, then place it in a constant temperature and humidity chamber, maintain the temperature inside the chamber at 50℃ and the humidity at 95-100%, and keep it for 12-24 hours. After natural cooling, install the connecting device to obtain the bulletproof mask.

[0014] Preferably, in step two, the polycarbonate hot bending temperature is 130–145°C, the holding time is 1–3 hours, and the mold is coated with a polycarbonate-cellulose composite. The glass plate hot bending temperature is 600–800°C, and the holding time is 2–3 hours.

[0015] Preferably, in step two, the water bath heating temperature is 80℃, and the heat preservation time is 5-8 hours; the drying method is to use a 55℃ forced-air drying oven to dry the polycarbonate board.

[0016] Preferably, in step three, the outer surface of the second polycarbonate plate is hardened by using a UV curing agent, with a coating thickness of 1–1.5 mm and a UV irradiation time of 18–24 h; the high-lithium silicate glass plate and the high-alumina silicate glass plate are chemically strengthened using a strengthening liquid, with a strengthening temperature of 360–380 °C and a holding time of 16–24 h; the anti-fog coating used is an organosilicon-modified hydrophilic resin, which is baked at 110–120 °C for 60–120 min.

[0017] Preferably, in step five, the sealing environment is a vacuum with a vacuum degree of 0.1 to 0.5 kPa, and the sealant is cured by natural cooling. Excess sealant residue at the edges is removed, and then the sealant is dried in an oven at 55°C for 6 to 8 hours.

[0018] Compared with the prior art, the advantages of the lightweight transparent bulletproof mask and its manufacturing method disclosed in this invention are:

[0019] (1) The present invention solves the common technical problem of moisture absorption and cracking of polyurethane adhesive in face masks by using a sealing process. Through wet fog curing technology, the tensile strength of heat-resistant PUR hot melt adhesive is maintained, the toughness of heat-resistant hot melt adhesive is improved, and the problem of cracking after sealing and curing of the sealing edge is solved.

[0020] (2) In the process of bending polycarbonate sheets, the present invention coats the mold with a polycarbonate-cellulose composite. The polycarbonate-cellulose composite has structural stability. After being coated on the surface of polycarbonate, it will adsorb with the functional groups of polycarbonate. Then, the polycarbonate sheet after hot bending is heated by water bath to maintain its shape. The polycarbonate sheet after hot bending can effectively maintain its shape and does not deform during the composite and baking stages. It successfully achieves stress-free composite of inorganic glass sheet and organic polycarbonate sheet. Moreover, the composite process of the present invention is simple and easy to operate. After composite, the polycarbonate sheet is free of defects such as fish scales, dotted lines, bubbles, and pores.

[0021] (3) The novel protective face mask prepared by the present invention did not show cracking or yellowing after environmental accelerated aging test. The polycarbonate used in the face mask has been surface hardened and has high wear resistance.

[0022] (4) The bulletproof mask prepared by the present invention has the characteristics of high protection capability, lightweight product, wear resistance and anti-fog. Under the protection level of public security level II, the present invention has achieved a weight reduction of more than 30% compared with the existing similar mask products. The product has passed the target shooting test of the Ministry of Public Security. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is an exploded view of a lightweight transparent bulletproof face shield disclosed in this invention.

[0025] Figure 2 This is a cross-sectional view of a bulletproof face shield.

[0026] In the diagram: 1-First polycarbonate sheet; 2-High aluminosilicate glass sheet; 3-High lithium silicate glass sheet; 4-Second polycarbonate sheet; 5-Thermoplastic polyurethane adhesive; 6-Low temperature resistant PUR hot melt adhesive. Detailed Implementation

[0027] The specific embodiments of the present invention will be briefly described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] Figures 1-2A preferred embodiment of the present invention is shown and analyzed in detail.

[0029] Example 1

[0030] like Figure 1 , 2 The lightweight transparent bulletproof face shield shown includes an inner layer, an outer layer, and a middle layer. The inner layer is a first polycarbonate sheet 1, the outer layer is a second polycarbonate sheet 4, and the middle layer consists of a high-alumina silicate glass sheet 2 and a high-lithium silicate glass sheet 3. These multiple layers are bonded together using a thermoplastic polyurethane adhesive 5. After bonding, the layers, from the inside out, are the first polycarbonate sheet 1, the high-alumina silicate glass sheet 2, the high-lithium silicate glass sheet 3, and the second polycarbonate sheet 4. The first polycarbonate sheet 1 has a thickness of 5.0 mm, the high-alumina silicate glass sheet 2 has a thickness of 4.0 mm, the high-lithium silicate glass sheet 3 has a thickness of 1.0 mm, the second polycarbonate sheet 4 has a thickness of 1.0 mm, and the thermoplastic polyurethane adhesive 5 has a thickness of 1.25 mm. The first polycarbonate plate 1 and the second polycarbonate plate 4 are the same size. The high-alumina silicate glass plate 2 and the high-lithium silicate glass plate 3 are the same size, but the glass plate is smaller than the polycarbonate plate. The edges of the glass plates are 2mm away from the edges of the polycarbonate plates. After lamination, they form a concave structure. The edges of the mask are sealed with low-temperature resistant PUR hot melt adhesive 6. The low-temperature resistant PUR hot melt adhesive 6 is applied inside the concave structure, and its outer surface is flush with the outer edge of the polycarbonate plate. The bulletproof mask is bent towards the face, and the side of the first polycarbonate plate 1 facing the face is sprayed with an anti-fog coating.

[0031] The method for preparing the above-mentioned lightweight transparent bulletproof face shield includes the following steps:

[0032] Step 1: Raw material preparation: 5.0mm first polycarbonate sheet 1, 4.0mm high aluminosilicate glass sheet 2, 1.0mm high lithium silicate glass sheet 3, 1.0mm second polycarbonate sheet 4, 1.25mm thermoplastic polyurethane adhesive 5, low temperature resistant PUR hot melt adhesive 6.

[0033] Step 2, Raw Material Shaping: Polycarbonate sheets and glass sheets are processed according to the design dimensions. A polycarbonate-cellulose composite is coated onto the mold. The required polycarbonate and glass sheets are bent into shape using a hot bending process and high-precision fixtures. The glass sheet is bent at 650℃ for 2 hours; the polycarbonate sheet is bent at 140℃ for 1 hour. The hot-bent polycarbonate sheets are then subjected to a shape-preserving treatment using an 80℃ water bath for 5 hours, followed by drying in a 55℃ forced-air drying oven.

[0034] Step 3: Raw material modification: The outer surface of the 1.0mm second polycarbonate plate 4 is hardened using a UV curing agent with a coating thickness of 1mm and a UV irradiation time of 24 hours. The 1.0mm high-lithium silicate glass plate 3 and the 4.0mm high-alumina silicate glass plate 2 are chemically strengthened using a commercially available strengthening solution. The main components of the commercial strengthening solution are a mixed salt solution of potassium nitrate, sodium nitrate, and magnesium nitrate. The strengthening temperature is 370℃, and the holding time is 16 hours. The silicone-modified hydrophilic resin sprayed on the inner surface of the 5.0mm first polycarbonate plate 1 is cured and shaped using a low-temperature baking method at 110℃ for 60 minutes.

[0035] Step 4, Composite Process: The raw materials processed in Step 3 are composited using a low-temperature and high-pressure composite method. The composite sequence is as follows: second polycarbonate plate 4, high-lithium silicate glass plate 3, high-alumina silicate glass plate 2, and first polycarbonate plate 1. Thermoplastic polyurethane adhesive 5 is used as the composite bonding material during the composite process.

[0036] Step 5, Sealing Process: Use low-temperature resistant PUR hot melt adhesive 6 to seal the edges of the composite mask; the sealing environment is a vacuum with a vacuum degree of 0.1Kpa, and it is allowed to cool and cure naturally. Remove excess adhesive residue from the edges, and then dry in an oven at 55℃ for 6 hours.

[0037] Step 6, Moist fog curing process: Coat the edges of the transparent mask obtained in step 5 with ethylene glycol, then place it in a constant temperature and humidity chamber, maintain the temperature inside the chamber at 50℃ and the humidity at 95% for 24 hours. After natural cooling, install the connecting device to obtain the bulletproof mask.

[0038] The bulletproof face shield was tested on a target with a 1954 7.62mm pistol and a 1951 7.62mm pistol cartridge (lead core).

[0039] Table 1 is a test record of the bulletproof mask target fabricated in Example 1:

[0040] Sample Model Temperature conditions range m Angle of fire ° Firing position Projectile velocity m / s Shot Situation Example 1 Normal temperature 22℃ 5 0 1 447 Not penetrated

[0041] The target test results show that the mask has good protective performance. After the target test, the mask did not delaminate, crack, or have any debris flying.

[0042] Example 2

[0043] like Figure 1 , 2The lightweight transparent bulletproof face shield shown includes an inner layer, an outer layer, and a middle layer. The inner layer is a first polycarbonate sheet 1, the outer layer is a second polycarbonate sheet 4, and the middle layer consists of a high-alumina silicate glass sheet 2 and a high-lithium silicate glass sheet 3. These multiple layers are bonded together using a thermoplastic polyurethane adhesive 5. After bonding, the layers, from the inside out, are the first polycarbonate sheet 1, the high-alumina silicate glass sheet 2, the high-lithium silicate glass sheet 3, and the second polycarbonate sheet 4. The first polycarbonate sheet 1 has a thickness of 5.0 mm, the high-alumina silicate glass sheet 2 has a thickness of 5.0 mm, the high-lithium silicate glass sheet 3 has a thickness of 1.0 mm, the second polycarbonate sheet 4 has a thickness of 1.0 mm, and the thermoplastic polyurethane adhesive 5 has a thickness of 1.25 mm. The first polycarbonate plate 1 and the second polycarbonate plate 4 are the same size. The high-alumina silicate glass plate 2 and the high-lithium silicate glass plate 3 are the same size, but the glass plate is smaller than the polycarbonate plate. The edges of the glass plates are 2mm away from the edges of the polycarbonate plates. After lamination, they form a concave structure. The edges of the mask are sealed with low-temperature resistant PUR hot melt adhesive 6. The low-temperature resistant PUR hot melt adhesive 6 is applied inside the concave structure, and its outer surface is flush with the outer edge of the polycarbonate plate. The bulletproof mask is bent towards the face, and the side of the first polycarbonate plate 1 facing the face is sprayed with an anti-fog coating.

[0044] The method for preparing the above-mentioned lightweight transparent bulletproof face shield includes the following steps:

[0045] Step 1: Raw material preparation: 1. 5.0mm first polycarbonate sheet, 2. 5.0mm high aluminosilicate glass sheet, 3. 1.0mm high lithium silicate glass sheet, 4. 1.0mm second polycarbonate sheet, 5. 1.25mm thermoplastic polyurethane adhesive, 6. Low-temperature resistant PUR hot melt adhesive.

[0046] Step 2, Raw Material Shaping: Polycarbonate sheets and glass sheets are processed according to the design dimensions. A polycarbonate-cellulose composite is coated onto the mold. The required polycarbonate and glass sheets are bent into shape using a hot bending process and high-precision fixtures. The glass sheet is hot-bent at 780℃ for 2.5 hours, and the polycarbonate sheet is hot-bent at 130℃ for 1 hour. The hot-bent polycarbonate sheets are then subjected to shape retention treatment using an 80℃ water bath for 8 hours, and finally dried in a 55℃ forced-air drying oven.

[0047] Step 3: Raw Material Modification: The outer surface of the 1.0mm second polycarbonate plate 4 is hardened using a UV curing agent with a coating thickness of 1.5mm and a UV irradiation time of 18 hours. The 1.0mm high-lithium silicate glass plate 3 and the 5.0mm high-alumina silicate glass plate 2 are chemically strengthened using a commercially available strengthening solution. The main components of the commercial strengthening solution are a mixed salt solution of potassium nitrate, sodium nitrate, and magnesium nitrate. The strengthening temperature is 360℃, and the holding time is 16 hours. The silicone-modified hydrophilic resin sprayed on the inner surface of the 5.0mm first polycarbonate plate 1 is cured and set using a low-temperature baking method at 120℃ for 60 minutes.

[0048] Step 4, Composite Process: The raw materials processed in Step 3 are composited using a low-temperature and high-pressure composite method. The composite sequence is as follows: second polycarbonate plate 4, high-lithium silicate glass plate 3, high-alumina silicate glass plate 2, and first polycarbonate plate 1. Thermoplastic polyurethane adhesive 5 is used as the composite bonding material during the composite process.

[0049] Step 5, Sealing Process: Use low-temperature resistant PUR hot melt adhesive 6 to seal the edges of the composite mask; the sealing environment is a vacuum with a vacuum degree of 0.1Kpa, and it is allowed to cool and cure naturally. Remove excess adhesive residue from the edges, and then dry in an oven at 55℃ for 8 hours.

[0050] Step 6, Moist fog curing process: Coat the edges of the transparent mask obtained in step 5 with ethylene glycol, then place it in a constant temperature and humidity chamber, maintain the temperature inside the chamber at 50℃ and the humidity at 95% for 24 hours. After natural cooling, install the connecting device to obtain the bulletproof mask.

[0051] The bulletproof face shield was tested on a target with a 1954 7.62mm pistol and a 1951 7.62mm pistol cartridge (lead core).

[0052] Table 2 is the test record of the bulletproof mask target made in Example 2:

[0053] Sample Model Temperature conditions range m Angle of fire ° Firing position Projectile velocity m / s Shot Situation Example 2 Normal temperature 22℃ 5 0 1 442 Not penetrated Example 2 Low temperature -25℃ 5 0 1 454 Not penetrated

[0054] The target test results show that the mask has good protective performance. After the target test, the mask did not delaminate, crack, or have any debris flying.

[0055] The above description of the disclosed embodiments enables those skilled in the art to make and 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 and 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 method for preparing a lightweight transparent bulletproof face shield, characterized in that, The bulletproof face shield includes an inner layer, an outer layer, and a middle layer. The inner layer is a first polycarbonate plate (1), the outer layer is a second polycarbonate plate (4), and the middle layer is a high-alumina silicate glass plate (2) and a high-lithium silicate glass plate (3). The multiple layers are bonded together using thermoplastic polyurethane adhesive (5). After bonding, from the inside out, the layers are the first polycarbonate plate (1), the high-alumina silicate glass plate (2), the high-lithium silicate glass plate (3), and the second polycarbonate plate (4). The edges of the face shield are sealed with low-temperature resistant PUR hot melt adhesive (6). The bulletproof face shield is bent towards the face, and the surface of the first polycarbonate plate (1) facing the face is sprayed with an anti-fog coating to form an anti-fog coating surface. The process includes the following steps: Step 1: Raw material preparation: First polycarbonate board (1), high aluminosilicate glass board (2), high lithium silicate glass board (3), second polycarbonate board (4), thermoplastic polyurethane adhesive (5), low temperature resistant PUR hot melt adhesive (6); Step 2, Raw Material Shaping: Polycarbonate sheets and glass sheets are processed according to the design dimensions, and then bent into the required shapes using a hot bending process and high-precision fixtures. The hot bending temperature for polycarbonate is 130~145℃, and the holding time is 1~3 hours, with the mold coated with a polycarbonate-cellulose composite. The hot bending temperature for glass sheets is 600~800℃, and the holding time is 2~3 hours. The hot-bent polycarbonate sheets are then subjected to shape retention treatment using a water bath heating method, followed by drying. Step 3, Raw material modification: Harden the outer surface of the second polycarbonate plate (4); chemically strengthen the high-lithium silicate glass plate (3) and the high-alumina silicate glass plate (2); spray an anti-fog coating on the inner surface of the first polycarbonate plate (1) using a low-temperature baking method. Step 4, Composite process: The raw materials processed in step 3 are composited using a low temperature and high pressure composite method. The composite sequence is as follows: second polycarbonate plate (4), high lithium silicate glass plate (3), high aluminosilicate glass plate (2), first polycarbonate plate (1). Thermoplastic polyurethane adhesive (5) is used as the composite adhesive material during the composite process. Step 5, Sealing process: Use low-temperature resistant PUR hot melt adhesive (6) to seal the edges of the composite mask; Step 6, wet fog curing process: Coat the edges of the transparent mask obtained in step 5 with ethylene glycol, then place it in a constant temperature and humidity chamber, maintain the temperature inside the chamber at 50 ℃ and the humidity at 95~100%, and keep it for 12~24 hours. After natural cooling, install the connecting device to obtain the bulletproof mask.

2. The method for preparing a lightweight transparent bulletproof face shield according to claim 1, characterized in that, The first polycarbonate plate (1) has a thickness of 5.0~6.0 mm, the high aluminosilicate glass plate (2) has a thickness of 4.0~8.0 mm, the high lithium silicate glass plate (3) has a thickness of 0.5~1.5 mm, the second polycarbonate plate (4) has a thickness of 0.5~1.5 mm, and the thermoplastic polyurethane adhesive (5) has a thickness of 0.6~1.8 mm. The first polycarbonate plate (1) and the second polycarbonate plate (4) have the same size, the high aluminosilicate glass plate (2) and the high lithium silicate glass plate (3) have the same size, the glass plate is smaller than the polycarbonate plate, and after being composited, they form a concave structure. Low temperature resistant PUR hot melt adhesive (6) is applied to the concave structure, and the outer surface is flush with the outer edge of the polycarbonate plate.

3. The method for preparing a lightweight transparent bulletproof face shield according to claim 1, characterized in that, In step two, the water bath heating temperature is 80 ℃, and the holding time is 5~8 h; the drying method is to use a 55 ℃ forced-air drying oven to dry the polycarbonate board.

4. The method for preparing a lightweight transparent bulletproof face shield according to claim 1, characterized in that, In step three, the outer surface of the second polycarbonate plate (4) is hardened by using a UV curing agent. The coating thickness of the curing agent is 1~1.5 mm, and the UV irradiation time is 18~24 h. The high lithium silicate glass plate (3) and the high aluminosilicate glass plate (2) are chemically strengthened using a strengthening liquid. The strengthening temperature is 360~380 ℃, and the heat preservation time is 16~24 h. The anti-fog coating used is an organosilicon modified hydrophilic resin, which is baked at 110~120 ℃ for 60~120 min.

5. The method for preparing a lightweight transparent bulletproof face shield according to claim 1, characterized in that, In step five, the sealing environment is a vacuum with a vacuum degree of 0.1~0.5 KPa. It is allowed to cool and cure naturally, and excess adhesive residue at the edges is removed. Then it is dried in an oven at 55℃ for 6~8 hours.

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