High-transmittance automobile lampshade light-transmitting piece and preparation method thereof

Abstract

A high-transmittance automobile lampshade light-transmitting piece and a preparation method thereof belong to the field of automobile lampshade light-transmitting pieces and comprise the following substances in parts by weight: 80-90 parts of polymethyl methacrylate, 4-6 parts of methacrylic acid, 1-2 parts of N-cyclohexyl maleimide, 0.7-0.9 parts of calcium stearate, 3-4 parts of nanoscale silane-modified silicon dioxide, 0.2-0.4 parts of ethoxy cocoalkylamine, 0.4-0.6 parts of 2,2'-dihydroxy-4-methoxybenzophenone, and 0.6-0.8 parts of 2,6-di-tert-butyl-4-methylphenol. In the application, polymethyl methacrylate is used in combination, thereby improving the thermal stability of polymethyl methacrylate and maintaining or further improving other properties of polymethyl methacrylate, so that the automobile lampshade light-transmitting piece made of polymethyl methacrylate material can be used stably for a long time.

Description

Technical Field

[0001] This invention belongs to the field of automotive lamp cover light-transmitting components, specifically a high light transmittance automotive lamp cover light-transmitting component and its preparation method. Background Technology

[0002] Automotive headlight lens elements are a key component of automotive lighting systems, and their light transmittance directly affects the lighting effect and driving safety. In current technology, automotive headlight lens elements are mostly made of polycarbonate (PC). Polycarbonate has good impact resistance and heat resistance, so it is widely used in the manufacture of automotive headlight lens elements. However, the light transmittance of polycarbonate automotive headlight lens elements is weaker than that of polymethyl methacrylate (PMMA), and its scratch resistance is also lower than that of PMMA. If it is scratched during use, its light transmittance will decrease, affecting the light intensity and uniformity of the headlight, thus increasing the safety hazards of nighttime driving.

[0003] Polymethyl methacrylate (PMMA) has good light transmittance and certain impact and scratch resistance, but its high-temperature resistance is poor. When car headlights are on for a long time, the temperature is high, which makes it prone to thermal deformation and softening under prolonged high-temperature conditions. This not only damages the structural integrity of the lamp cover, but also causes optical performance degradation due to the intensified thermal movement of the molecular chains inside the material, such as decreased light transmittance and yellowing, affecting the lifespan of the lamp cover and the lighting effect. Summary of the Invention

[0004] This invention provides a high light transmittance automotive lamp cover light-transmitting component and its preparation method, in order to overcome the defects in the prior art.

[0005] This invention is achieved through the following technical solution: A high-transmittance automotive lamp cover light-transmitting component comprises the following substances in parts by weight: 80-90 parts polymethyl methacrylate, 4-6 parts methacrylic acid, 1-2 parts N-cyclohexylmaleimide, 0.7-0.9 parts calcium stearate, 3-4 parts nano-grade silane-modified silica, 0.2-0.4 parts ethoxycocoylamine, 0.4-0.6 parts 2,2'-dihydroxy-4-methoxybenzophenone, and 0.6-0.8 parts 2,6-di-tert-butyl-4-methylphenol.

[0006] The high light transmittance automotive lamp cover light-transmitting component described above, wherein the polymethyl methacrylate has a number average molecular weight of 50,000-80,000.

[0007] The high light transmittance automotive lamp cover light-transmitting component described above has a total amine value of 70-100 mg KOH / g for the ethoxycocoyl alkylamine.

[0008] A method for preparing a high-transmittance automotive lamp cover light-transmitting component, characterized by comprising the following steps: Step 1: Weigh out the following ingredients according to the specified ratio: polymethyl methacrylate, methacrylic acid, N-cyclohexylmaleimide, calcium stearate, nano-sized silane-modified silica, ethoxycocoylamine, 2,2'-dihydroxy-4-methoxybenzophenone, and 2,6-di-tert-butyl-4-methylphenol. Step 2: Mix polymethyl methacrylate, methacrylic acid, N-cyclohexylmaleimide and 2,6-di-tert-butyl-4-methylphenol and then add them to a mixer for melt mixing; Step 3: Add ethoxycocoylamine and 2,2'-dihydroxy-4-methoxybenzophenone to the mixer and continue to melt and mix; Step 4: Add calcium stearate and nano-sized silane-modified silica to the mixer and mix thoroughly; Step 5: The uniformly mixed material in the mixer is injection molded using a high-gloss mirror mold to obtain the injection molded part; Step Six: After injection molding, dust removal and static electricity removal operations are performed to obtain high light transmittance automotive lamp cover light-transmitting parts.

[0009] In the above-described method for preparing a high-transmittance automotive lamp cover light-transmitting component, the temperature of the mixer in step two is 150-155℃, the stirring speed of the mixer is 100-120 rad / min, and the mixing time is 50-60 min.

[0010] In the above-described method for preparing a high-transmittance automotive lamp cover light-transmitting component, the temperature of the mixer in step three is 153-158℃, the stirring speed of the mixer is 80-100 rad / min, and the mixing time is 20-25 min.

[0011] In the above-described method for preparing a high-transmittance automotive lamp cover light-transmitting component, the temperature of the mixer in step four is 155-159℃, the stirring speed of the mixer is 130-150 rad / min, and the mixing time is 30-40 min.

[0012] As described above, in the method for preparing a high-transmittance automotive lamp cover light-transmitting component, the injection molding operation in step five is as follows: before injection molding, the temperature of the high-gloss mirror mold is heated to 150-155℃, and then the molten mixture is injected into the high-gloss mirror mold at an injection pressure of 100-120MPa. After injection, the high-gloss mirror mold is maintained at a pressure of 60-80MPa, and the temperature of the high-gloss mirror mold is reduced to 40-60℃ by water cooling, with the cooling rate controlled at 6-10℃ / s. Then, the injection molded part is naturally cooled to room temperature and removed.

[0013] As described above, in the method for preparing a high light transmittance automotive lamp cover light-transmitting component, the dust removal operation in step six is ​​as follows: compressed air with a pressure of 0.3-0.5MPa is used to blow the surface of the injection molded part from multiple angles, and then a dust-free fiber cloth is dipped in isopropyl alcohol and gently wiped along the same direction. The electrostatic removal operation in step six is ​​as follows: use an ion gun to blow on the surface of the light-transmitting part. The working voltage of the ion gun is 220V, the wind speed is 3-5m / s, and the blowing time is 10-15s.

[0014] The advantages of this invention are: by using polymethyl methacrylate (PMMA) in combination, its thermal stability is improved, and other properties of PMMA are maintained or further improved. This allows PMMA-based automotive lamp light-transmitting components to be used stably for a long time. Furthermore, PMMA is cheaper than polycarbonate, especially since polycarbonate requires the use of more expensive optical polycarbonate to fit the light-transmitting components. Therefore, using PMMA to prepare automotive lamp light-transmitting components further reduces production costs compared to polycarbonate. The copolymer structure of methacrylic acid and PMMA in this invention enhances the interaction between molecular chains and improves the material's properties. The thermal stability is improved by introducing N-cyclohexylmaleimide, which increases the glass transition temperature and further enhances thermal stability. Calcium stearate optimizes processing flowability and reduces frictional loss during molding. Nanoscale silane-modified silica enhances wear resistance and reduces scattering while improving light transmittance through interfacial bonding. Ethoxycocoylamine improves the dispersion uniformity of each component and prevents phase separation. 2,2'-Dihydroxy-4-methoxybenzophenone effectively absorbs ultraviolet light and delays aging and yellowing. 2,6-Di-tert-butyl-4-methylphenol inhibits aging degradation and extends the service life of the material, thus giving the composite automotive lamp cover light-transmitting component excellent performance. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the assembled high-transmittance automotive lamp cover light-transmitting component prepared in Embodiment 3 of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1

[0019] Step 1: Weigh out the following components according to the specified ratio: 80 parts polymethyl methacrylate (number average molecular weight 50,000), 4 parts methacrylic acid, 1 part N-cyclohexylmaleimide, 0.7 parts calcium stearate, 3 parts nano-sized silane-modified silica, 0.2 parts ethoxycocoylamine (total amine value 70 mg KOH / g), 0.4 parts 2,2'-dihydroxy-4-methoxybenzophenone, and 0.6 parts 2,6-di-tert-butyl-4-methylphenol. Step 2: Mix polymethyl methacrylate, methacrylic acid, N-cyclohexylmaleimide and 2,6-di-tert-butyl-4-methylphenol and add them to a mixer for melt mixing. The temperature of the mixer is 150℃, the stirring speed of the mixer is 100 rad / min, and the mixing time is 60 min. Step 3: Add ethoxycocoylamine and 2,2'-dihydroxy-4-methoxybenzophenone to the mixer and continue to melt and mix. The temperature of the mixer is 153℃, the stirring speed of the mixer is 80 rad / min, and the mixing time is 25 min. Step 4: Add calcium stearate and nano-sized silane-modified silica to the mixer and mix evenly. The temperature of the mixer is 155℃, the stirring speed of the mixer is 130 rad / min, and the mixing time is 40 min. Step 5: Inject the uniformly mixed material in the mixer into a high-gloss mirror mold. Before injection, heat the high-gloss mirror mold to 150°C. Then, inject the molten mixture into the high-gloss mirror mold at an injection pressure of 100MPa. After injection, maintain a pressure of 60MPa in the high-gloss mirror mold and reduce the temperature of the high-gloss mirror mold to 40°C by water cooling. The cooling rate is controlled at 6-10°C / s. Then, allow it to cool naturally to room temperature and remove the injection molded part. Step Six: The injection molded part is blown from multiple angles using compressed air at a pressure of 0.3 MPa. Then, a dust-free fiber cloth is dipped in isopropyl alcohol and gently wiped along the same direction. After that, an ion air gun is used to blow the surface of the light-transmitting part. The working voltage of the ion air gun is 220V, the air speed is 3m / s, and the blowing time is 15s, resulting in a high light transmittance automotive lamp cover light-transmitting part.

[0020] Example 2

[0021] Step 1: Weigh out the following components according to the specified ratio: 90 parts polymethyl methacrylate (number average molecular weight 80,000), 6 parts methacrylic acid, 2 parts N-cyclohexylmaleimide, 0.9 parts calcium stearate, 4 parts nano-sized silane-modified silica, 0.4 parts ethoxycocoylamine (total amine value 100 mg KOH / g), 0.6 parts 2,2'-dihydroxy-4-methoxybenzophenone, and 0.8 parts 2,6-di-tert-butyl-4-methylphenol. Step 2: Mix polymethyl methacrylate, methacrylic acid, N-cyclohexylmaleimide and 2,6-di-tert-butyl-4-methylphenol and add them to a mixer for melt mixing. The temperature of the mixer is 155℃, the stirring speed of the mixer is 120 rad / min, and the mixing time is 50 min. Step 3: Add ethoxycocoylamine and 2,2'-dihydroxy-4-methoxybenzophenone to the mixer and continue to melt and mix. The temperature of the mixer is 158°C, the stirring speed of the mixer is 100 rad / min, and the mixing time is 20 min. Step 4: Add calcium stearate and nano-sized silane-modified silica to the mixer and mix evenly. The temperature of the mixer is 159℃, the stirring speed of the mixer is 150 rad / min, and the mixing time is 30 min. Step 5: Inject the uniformly mixed material in the mixer into a high-gloss mirror mold. Before injection, heat the high-gloss mirror mold to 155°C. Then, inject the molten mixture into the high-gloss mirror mold at an injection pressure of 120MPa. After injection, maintain the high-gloss mirror mold at a pressure of 80MPa and reduce the temperature of the high-gloss mirror mold to 60°C by water cooling. The cooling rate is controlled at 6-10°C / s. Then, allow it to cool naturally to room temperature and remove the injection molded part. Step Six: The injection molded part is blown from multiple angles using compressed air at a pressure of 0.5MPa. Then, a dust-free fiber cloth is dipped in isopropyl alcohol and gently wiped along the same direction. Next, an ion air gun is used to blow the surface of the light-transmitting part. The working voltage of the ion air gun is 220V, the air speed is 5m / s, and the blowing time is 10s, resulting in a high light transmittance automotive lamp cover light-transmitting part.

[0022] Example 3

[0023] Step 1: Weigh out the following components according to the specified ratio: 85 parts polymethyl methacrylate (number average molecular weight 65000), 5 parts methacrylic acid, 1.5 parts N-cyclohexylmaleimide, 0.8 parts calcium stearate, 3.5 parts nano-sized silane-modified silica, 0.3 parts ethoxycocoylamine (total amine value 85mgKOH / g), 0.5 parts 2,2'-dihydroxy-4-methoxybenzophenone, and 0.7 parts 2,6-di-tert-butyl-4-methylphenol. Step 2: Mix polymethyl methacrylate, methacrylic acid, N-cyclohexylmaleimide and 2,6-di-tert-butyl-4-methylphenol and add them to a mixer for melt mixing. The temperature of the mixer is 153℃, the stirring speed of the mixer is 110 rad / min, and the mixing time is 55 min. Step 3: Add ethoxycocoylamine and 2,2'-dihydroxy-4-methoxybenzophenone to the mixer and continue to melt and mix. The temperature of the mixer is 156℃, the stirring speed of the mixer is 90 rad / min, and the mixing time is 23 min. Step 4: Add calcium stearate and nano-sized silane-modified silica to the mixer and mix evenly. The temperature of the mixer is 157℃, the stirring speed of the mixer is 140 rad / min, and the mixing time is 35 min. Step 5: The uniformly mixed material in the mixer is injection molded using a high-gloss mirror mold. Before injection, the temperature of the high-gloss mirror mold is heated to 153℃. Then, the molten mixture is injected into the high-gloss mirror mold at an injection pressure of 110MPa. After injection, the high-gloss mirror mold is kept at a pressure of 70MPa, and the temperature of the high-gloss mirror mold is reduced to 50℃ by water cooling at a rate of 6-10℃ / s. Then, the molded part is removed after natural cooling to room temperature. Step Six: The injection molded part is blown from multiple angles using compressed air at a pressure of 0.4 MPa. Then, a clean, dust-free fiber cloth soaked in isopropyl alcohol is used to gently wipe the surface in the same direction. Next, an ion gun is used to blow the surface of the light-transmitting part. The ion gun operates at 220V, with a wind speed of 4 m / s and a blowing time of 13 seconds, resulting in a high-transmittance automotive lamp cover (as shown in the assembled photo). Figure 1 (As shown).

[0024] Comparative Example Step 1: Add polymethyl methacrylate (number average molecular weight of 65,000) to a mixer for melting. The temperature of the mixer is 153°C, the stirring speed of the mixer is 110 rad / min, and the melting time is 55 min. Step 2: Inject the molten material in the mixer into a high-gloss mirror mold. Before injection, heat the high-gloss mirror mold to 153°C. Then, inject the molten mixture into the high-gloss mirror mold at an injection pressure of 110MPa. After injection, maintain the high-gloss mirror mold at a pressure of 70MPa and reduce the temperature of the high-gloss mirror mold to 50°C by water cooling at a rate of 6-10°C / s. Then, allow it to cool naturally to room temperature and remove the injection molded part. Step 3: The injection molded part is blown from multiple angles using compressed air at a pressure of 0.4MPa. Then, a dust-free fiber cloth is dipped in isopropyl alcohol and gently wiped along the same direction. After that, an ion air gun is used to blow the surface of the light-transmitting part. The working voltage of the ion air gun is 220V, the air speed is 4m / s, and the blowing time is 13s, resulting in the light-transmitting part of the automotive lamp cover.

[0025] The high-transmittance automotive lamp cover light-transmitting parts prepared in Examples 1-3 and the comparative examples were tested for aging resistance (using the xenon arc lamp irradiation method of GB / T 16422.2-2014 "Laboratory Light Source Exposure Test Method for Plastics"), light transmittance (using the method of GB / T 2410-2008 "Determination of Light Transmittance and Haze of Transparent Plastics"), and impact strength (using the method of GB / T 1843-2008 "Determination of Impact Strength of Plastic Cantilever Beams"). For light transmittance testing, samples were taken first for light transmittance testing, followed by aging resistance testing, and then light transmittance testing was performed again. For impact strength testing, samples were taken first for impact strength testing, followed by aging resistance testing, and then impact strength testing was performed again. The aging resistance was determined by comparing the changes in light transmittance and impact strength before and after aging treatment. All performance tests were performed in ten groups, and the average value was recorded. The results are shown in Tables 1 and 2.

[0026]

[0027] Table 1

[0028] Table 2 As shown in Tables 1 and 2, the high-transmittance automotive lampshade light-transmitting components prepared in Examples 1-3 of this invention all had a transmittance higher than 93.7% before aging, and the transmittance remained above 89.7% after aging. In contrast, the transmittance of the comparative example was only 91.7% before aging, and dropped to 81.2% after aging, a significantly greater decrease than that of Examples 1-3. Regarding impact strength, the high-transmittance automotive lampshade light-transmitting components prepared in Examples 1-3 of this invention all had an impact strength exceeding 1760 J / m before aging. 2 Even after aging, it still maintains a value of 1579 J / m.2 The above figures show that the impact strength of the comparative model before aging was 1236.8 J / m. 2 After aging, it only has 852.9 J / m³. 2 The performance degradation is obvious; as can be seen from the above data, the high light transmittance automotive lamp cover light transmittance component prepared by the present invention has excellent optical performance, mechanical performance and durability, which can meet the requirements of long-term stable use of automotive lamp cover light transmittance components. At the same time, the production cost is reduced by using lower-priced polymethyl methacrylate instead of optical polycarbonate, and it has high practical application value.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high light transmittance automotive lamp cover light-transmitting component, characterized in that: The substance comprises the following components in parts by weight: 80-90 parts polymethyl methacrylate, 4-6 parts methacrylic acid, 1-2 parts N-cyclohexylmaleimide, 0.7-0.9 parts calcium stearate, 3-4 parts nano-sized silane-modified silica, 0.2-0.4 parts ethoxycocoylamine, 0.4-0.6 parts 2,2'-dihydroxy-4-methoxybenzophenone, and 0.6-0.8 parts 2,6-di-tert-butyl-4-methylphenol.

2. The high light transmittance automotive lamp cover light-transmitting component according to claim 1, characterized in that: The polymethyl methacrylate has a number average molecular weight of 50,000-80,000.

3. The high light transmittance automotive lamp cover light-transmitting component according to claim 1, characterized in that: The total amine value of the ethoxycocoyl alkylamine is 70-100 mg KOH / g.

4. A method for preparing a high-transmittance automotive lamp cover light-transmitting component, characterized in that: The steps include the following: Step 1: Weigh out the following ingredients according to the specified ratio: polymethyl methacrylate, methacrylic acid, N-cyclohexylmaleimide, calcium stearate, nano-sized silane-modified silica, ethoxycocoylamine, 2,2'-dihydroxy-4-methoxybenzophenone, and 2,6-di-tert-butyl-4-methylphenol. Step 2: Mix polymethyl methacrylate, methacrylic acid, N-cyclohexylmaleimide and 2,6-di-tert-butyl-4-methylphenol and then add them to a mixer for melt mixing; Step 3: Add ethoxycocoylamine and 2,2'-dihydroxy-4-methoxybenzophenone to the mixer and continue to melt and mix; Step 4: Add calcium stearate and nano-sized silane-modified silica to the mixer and mix thoroughly; Step 5: The uniformly mixed material in the mixer is injection molded using a high-gloss mirror mold to obtain the injection molded part; Step Six: After injection molding, dust removal and static electricity removal operations are performed to obtain high light transmittance automotive lamp cover light-transmitting parts.

5. The method for preparing a high light transmittance automotive lamp cover light-transmitting component according to claim 1, characterized in that: In step two, the temperature of the mixer is 150-155℃, the stirring speed of the mixer is 100-120 rad / min, and the mixing time is 50-60 min.

6. The method for preparing a high light transmittance automotive lamp cover light-transmitting component according to claim 1, characterized in that: In step three, the temperature of the mixer is 153-158℃, the stirring speed of the mixer is 80-100 rad / min, and the mixing time is 20-25 min.

7. The high light transmittance automotive lamp cover light-transmitting component according to claim 1, characterized in that: In step four, the temperature of the mixer is 155-159℃, the stirring speed of the mixer is 130-150 rad / min, and the mixing time is 30-40 min.

8. The method for preparing a high light transmittance automotive lamp cover light-transmitting component according to claim 1, characterized in that: The injection molding operation in step five is as follows: Before injection molding, the temperature of the high-gloss mirror mold is heated to 150-155℃, and then the molten mixture is injected into the high-gloss mirror mold at an injection pressure of 100-120MPa. After injection, the high-gloss mirror mold is kept at a pressure of 60-80MPa, and the temperature of the high-gloss mirror mold is reduced to 40-60℃ by water cooling at a rate of 6-10℃ / s. Then the injection molded part is removed after natural cooling to room temperature.

9. The method for preparing a high light transmittance automotive lamp cover light-transmitting component according to claim 1, characterized in that: The dust removal operation in step six is ​​as follows: compressed air with a pressure of 0.3-0.5MPa is used to blow the surface of the injection molded part from multiple angles, and then a dust-free fiber cloth is dipped in isopropyl alcohol and gently wiped along the same direction. The electrostatic removal operation in step six is ​​as follows: use an ion gun to blow on the surface of the light-transmitting part. The working voltage of the ion gun is 220V, the wind speed is 3-5m / s, and the blowing time is 10-15s.

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