Preparation method of optical lens

Abstract

A preparation method of an optical lens belongs to the technical field of optical imaging elements, and comprises the following steps: adding tripropylene glycol diacrylate and 3-aminopropyltriethoxysilane into tetrahydrofuran, and carrying out an addition reaction to obtain acrylate triethoxysilane; the preparation method comprises the following steps: adding tetraethoxysilane into a solvent, uniformly mixing, adding hydrochloric acid, carrying out hydrolysis reaction, adding acrylate triethoxysilane, uniformly mixing, adding acetic acid, carrying out polymerization reaction, and aging to obtain modified silica sol; removing the solvent from the modified silica sol, mixing the modified silica sol with epoxy acrylate and a light curing agent, coating a lens main body with the mixture, and performing light curing to obtain the optical lens. The optical lens prepared by the invention can have good transmittance, surface hardness and wear resistance only through photocuring.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical imaging elements, and particularly relates to a preparation method of an optical lens. Background Art

[0002] An optical lens is an optical element made of a transparent material such as optical glass, resin or crystal, which can regulate the propagation direction, intensity and spectral distribution of light through physical phenomena such as refraction and reflection, and has the advantages of high light transmittance and high anti-reflection ability. Among them, resin lenses are widely used in vision correction, medical equipment and 3C products due to their advantages such as light weight, safety and diverse functions. However, the optical performance of resin lenses is inferior to that of glass lenses, and they have low hardness and are easily scratched.

[0003] In the prior art, resin lenses need to be stacked with multiple functional thin films to improve their practicality and optical performance. For example, a hard coating (to improve the surface hardness of the lens and reduce scratches) + an anti-reflection coating (to reduce light reflection loss and improve light transmittance) + an anti-fouling coating (to prevent oil stains and fingerprints from adhering and facilitate cleaning). However, due to the poor heat resistance of resin lenses, the high-temperature curing of the thin film will damage the resin lens, and the more coating layers there are, the more likely the lens is to cause film layer peeling due to environmental factors (such as high temperature). Therefore, improvement is needed. Summary of the Invention

[0004] In view of the above situation, to overcome at least some defects of the above prior art, the present invention provides a preparation method of an optical lens.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: The present invention provides a preparation method of an optical lens, which is characterized by comprising: Taking dipropylene glycol diacrylate and 3-aminopropyltriethoxysilane and adding them into tetrahydrofuran, and performing an addition reaction to obtain acrylate triethoxysilane; Taking tetraethyl orthosilicate and adding it into a solvent, mixing evenly, adding hydrochloric acid, performing a hydrolysis reaction, adding acrylate triethoxysilane, mixing evenly, adding acetic acid for a polymerization reaction, and obtaining modified silica sol after aging; After removing the solvent from the modified silica sol, mixing it with epoxy acrylate and a photoinitiator, coating it on the lens body, and obtaining an optical lens after photocuring.

[0006] In some embodiments, the molar ratio of dipropylene glycol diacrylate to 3-aminopropyltriethoxysilane is 1:(0.8 - 1.2), the temperature of the addition reaction is 20°C - 30°C, and the time is 20h - 40h.

[0007] In some embodiments, the solvent includes ethanol and deionized water, the mass ratio of ethanol to deionized water is 1:(2 - 3), the temperature of the hydrolysis reaction is 30°C - 40°C, and the time is 1h - 2h.

[0008] In some embodiments, the mass ratio of tetraethyl orthosilicate to acrylate triethoxysilane is 1:(1 - 2), the temperature of the polymerization reaction is 50°C - 60°C, and the time is 4h - 5h.

[0009] In some embodiments, the mass ratio of the solvent, hydrochloric acid, and acetic acid is 100:(1 - 3):(10 - 25).

[0010] In some embodiments, the temperature of the aging is 20°C - 30°C, and the time is 3 - 5 days.

[0011] In some embodiments, the mass ratio of the epoxy acrylate, modified silica sol, and photoinitiator mixture is 60:(10 - 20):(3 - 6).

[0012] In some embodiments, the photoinitiator is one of 1 - hydroxy - cyclohexyl - phenyl - methanone, 2 - hydroxy - 4′-(2 - hydroxyethoxy)-2 - methylpropiophenone, 2,4,6 - trimethylbenzoyl - diphenylphosphine oxide, and 2 - hydroxy - 2 - methyl - 1 - phenyl - 1 - propanone.

[0013] In some embodiments, the photocuring is carried out using a photocuring machine, the time is 2min - 5min, and the temperature is 20°C - 50°C.

[0014] In some embodiments, the lens body is made of resin.

[0015] The beneficial effects achieved by the present invention are as follows: The present invention synthesizes acrylate triethoxysilane from dipropylene glycol diacrylate and 3 - aminopropyltriethoxysilane, then uses acrylate triethoxysilane and tetraethyl orthosilicate as raw materials to synthesize modified silica sol by the sol - gel method, and mixes the modified silica sol with epoxy acrylate to prepare a photocurable film with good transmittance and wear resistance. Detailed Embodiments

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments; based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0017] Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to the described content can be applied to the present invention. The preferred methods and materials described herein are for illustrative purposes only and do not limit the content of this application.

[0018] In view of the deficiencies in the prior art mentioned in the background art, an embodiment of the present invention provides a method for preparing an optical lens, including: Take dipropylene glycol diacrylate and 3-aminopropyltriethoxysilane and add them to tetrahydrofuran. After an addition reaction, acrylate triethoxysilane is obtained. Take tetraethyl orthosilicate and add it to a solvent. After mixing evenly, add hydrochloric acid. After a hydrolysis reaction, add acrylate triethoxysilane. After mixing evenly, add acetic acid for a polymerization reaction. After aging, a modified silica sol is obtained. After removing the solvent from the modified silica sol, mix it with epoxy acrylate and a photoinitiator, coat it on the lens body, and obtain an optical lens after photocuring.

[0019] Research has found that using tetraethyl orthosilicate to prepare a silica coating by the sol-gel method can significantly improve the light transmittance of the lens. However, the coating film prepared from silica is relatively brittle. Therefore, it is necessary to match it with other functional films. However, the more coating layers there are, the more likely the lens is to cause film layer peeling due to environmental factors (such as high temperature).

[0020] To solve the above problems, the present invention first prepares acrylate triethoxysilane by an addition reaction using dipropylene glycol diacrylate and 3-aminopropyltriethoxysilane. Then, using tetraethyl orthosilicate as the silicon source, by first adding hydrochloric acid to hydrolyze tetraethyl orthosilicate to generate oligomeric silicic acid, and then adding acrylate triethoxysilane, under the catalysis of acetic acid, a modified silica sol is prepared by a condensation reaction with the hydrolyzed oligomeric silicic acid. The modified silica sol has both the high hardness and heat resistance of inorganic silica and the flexibility of organic polymers, and introduces acrylate groups that can be photocured. By mixing the modified silica sol with epoxy acrylate and coating it on the lens body, a lens film with high wear resistance and transmittance can be obtained only by photocuring, which can enhance the light transmittance, surface hardness and wear resistance of the optical lens, and at the same time avoid damage to the lens body caused by high-temperature curing.

[0021] In some embodiments, the molar ratio of dipropylene glycol diacrylate to 3-aminopropyltriethoxysilane is 1:(0.8 - 1.2), the temperature of the addition reaction is 20°C - 30°C, and the time is 20 h - 40 h. Since dipropylene glycol diacrylate contains two acrylate groups, and the prepared acrylate triethoxysilane is a product of unilateral addition, setting the molar ratio of dipropylene glycol diacrylate to 3-aminopropyltriethoxysilane to 1:(0.8 - 1.2) can prevent the yield of the product acrylate triethoxysilane from being too low due to too little 3-aminopropyltriethoxysilane added, and can also prevent an increase in by-products (such as products of bilateral addition) due to too much 3-aminopropyltriethoxysilane added.

[0022] In some embodiments, the solvent includes ethanol and deionized water, the mass ratio of ethanol to deionized water is 1:(2 - 3), the temperature of the hydrolysis reaction is 30°C - 40°C, and the time is 1 h - 2 h. Since the hydrolysis of tetraethyl orthosilicate requires water as a reactant, the polarity of ethanol is lower than that of water and ethanol can dissolve tetraethyl orthosilicate, and the mass ratio of deionized water to ethanol in the solvent can control the hydrolysis and polycondensation reaction rates. By setting the mass ratio of ethanol to deionized water to 1:(2 - 3), the reaction rate can be prevented from being too fast or too slow.

[0023] In some embodiments, the mass ratio of tetraethyl orthosilicate to acrylate triethoxysilane is 1:(1 - 2), the temperature of the polymerization reaction is 50°C - 60°C, and the time is 4 h - 5 h. During the reaction, Si-OH on the surface of the silica sol will condense. Too little addition of acrylate triethoxysilane will result in insufficient modification of the silica sol, and too much addition of acrylate triethoxysilane will remain after re-curing, thus affecting the performance of the optical lens.

[0024] In some embodiments, the mass ratio of the solvent, hydrochloric acid, and acetic acid is 100:(1 - 3):(10 - 25). Hydrochloric acid, as a strong acid, mainly functions to catalyze the hydrolysis of tetraethyl orthosilicate. At the same time, its high catalytic efficiency only requires a small amount to effectively promote the reaction. Excessive hydrochloric acid will cause the reaction to be too fast and affect the stability of the silica sol. The further addition of acetic acid can adjust the pH value, which is beneficial to promoting the condensation reaction.

[0025] In some embodiments, the temperature of aging is 20°C - 30°C, and the time is 3 - 5 days. The condensation reaction between the ethoxy group of acrylate triethoxysilane and the hydroxyl group on the surface of the silica sol will continue during the aging stage. Through aging treatment, a denser covalent network can be promoted to form in the modified silica sol, thereby improving the light transmittance, mechanical strength, and durability of the thin film layer.

[0026] In some embodiments, the mass ratio of epoxy acrylate, modified silica sol, and photoinitiator is 60:(10 - 20):(3 - 6). Since the modified silica sol contains acrylate groups, the modified silica sol has high compatibility with epoxy acrylate, and the addition amount of the modified silica sol can be appropriately increased. Among them, the higher the addition amount of the modified silica sol, the better the transmittance and wear resistance of the thin film layer. However, adding too much will reduce the surface hardness of the thin film layer. In addition, the photoinitiator can initiate the rapid curing of the modified silica sol and epoxy acrylate. Adding too little will result in incomplete curing, and adding too much will cause residues, leading to a reduction in the optical properties of the thin film layer. Therefore, the mass ratio of epoxy acrylate, modified silica sol, and photoinitiator is set to 60:(10 - 20):(3 - 6).

[0027] In some embodiments, the photoinitiator is one of 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and 2-hydroxy-2-methyl-1-phenyl-1-propanone. The above photoinitiators all have a fast curing speed, can improve the curing efficiency of the thin film, and can have a good inhibitory effect on yellowing, thereby improving the transmittance of the thin film.

[0028] In some embodiments, photo-curing is carried out using a photo-curing machine for 2 min - 5 min at a temperature of 20°C - 50°C. Among them, the irradiation time of 2 - 5 minutes can ensure that the photoinitiator fully absorbs the photon energy, complete the generation of excited-state free radicals, complete the polymerization reaction, and promote photo-curing. Limiting the temperature to 20°C - 50°C can prevent the curing efficiency from being too poor due to too low a temperature, and at the same time prevent damage to the lens body due to too high a temperature.

[0029] In some embodiments, the lens body is made of resin. The resin material has the advantages of being light and safe, and compared with the glass material, the resin material is easier to process and form, thereby increasing the applicability of the optical lens and enriching the use functions of the optical lens.

[0030] The present invention will be further described below by way of specific embodiments.

[0031] The experimental methods in the following embodiments are all conventional methods unless otherwise specified; the test materials used in the following embodiments are all obtained from commercial channels unless otherwise specified.

[0032] Example 1 Take dipropylene glycol diacrylate and 3-aminopropyltriethoxysilane in a molar ratio of 1:0.8, add them to tetrahydrofuran, and react at 20°C for 20 h to obtain acrylate triethoxysilane; TEOS was added to a solvent. The mass ratio of ethanol to deionized water in the solvent was 1:2. After mixing evenly, hydrochloric acid was added, and the reaction was carried out at 30 °C for 1 h. Then, acrylate triethoxysilane was added. The mass ratio of TEOS to acrylate triethoxysilane was 1:1. After mixing evenly, acetic acid was added. The mass ratio of the solvent, hydrochloric acid and acetic acid was 100:1:10. The reaction was carried out at 50 °C for 4 h. After aging, a modified silica sol was obtained. The aging temperature was 20 °C and the time was 3 days. After removing the solvent from the modified silica sol, it was mixed with epoxy acrylate and its photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone. The mass ratio of epoxy acrylate, modified silica sol and photoinitiator was 60:10:3. It was coated on the lens body and an optical lens was obtained after photocuring.

[0033] Example 2 Di(propylene glycol) diacrylate and 3-aminopropyltriethoxysilane were taken in a molar ratio of 1:1.2 and added to tetrahydrofuran. The reaction was carried out at 40 °C for 40 h to obtain acrylate triethoxysilane. TEOS was added to a solvent. The mass ratio of ethanol to deionized water in the solvent was 1:3. After mixing evenly, hydrochloric acid was added, and the reaction was carried out at 40 °C for 2 h. Then, acrylate triethoxysilane was added. The mass ratio of TEOS to acrylate triethoxysilane was 1:2. After mixing evenly, acetic acid was added. The mass ratio of the solvent, hydrochloric acid and acetic acid was 100:3:25. The reaction was carried out at 60 °C for 5 h. After aging, a modified silica sol was obtained. The aging temperature was 30 °C and the time was 5 days. After removing the solvent from the modified silica sol, it was mixed with epoxy acrylate and its photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone. The mass ratio of epoxy acrylate, modified silica sol and photoinitiator was 60:20:6. It was coated on the lens body and an optical lens was obtained after photocuring.

[0034] Example 3 Consistent with Example 1, the difference was that the mass ratio of epoxy acrylate, modified silica sol and photoinitiator was 60:12:3.

[0035] Example 4 Consistent with Example 1, the difference was that the mass ratio of epoxy acrylate, modified silica sol and photoinitiator was 60:14:3.

[0036] Example 5 Consistent with Example 1, the difference was that the mass ratio of epoxy acrylate, modified silica sol and photoinitiator was 60:16:3.

[0037] Example 6 Consistent with Example 1, the difference is that the mass ratio of epoxy acrylate, modified silica sol and photo-curing agent in the mixture is 60:18:3.

[0038] Comparative Example 1 Consistent with Example 1, the difference is that no modified silica sol is prepared, that is, acrylate triethoxysilane is not added to the silica sol, and conventional silica sol is used instead of the modified silica sol.

[0039] Perform performance tests on the optical lenses prepared in Examples 1-6 and Comparative Example 1. The specific test contents are as follows: Transmittance test: Adopt Method B in the national standard "GBT2410-2008: Determination of Transmittance and Haze of Transparent Materials": Spectrophotometer method. For the transmittance test, use the ultraviolet / visible / near-infrared spectrophotometer Lambda750 of PerkinElmer company with an integrating sphere to test the transmittance of the optical lens. The transmittance is the ratio of the luminous flux passing through the sample to the luminous flux incident on the sample, expressed as a percentage.

[0040] Pencil hardness test: Adopt the national standard "GB / T6739-2006: Determination of Film Hardness by Pencil Method for Paints and Varnishes" to conduct the pencil hardness test. Place the sample in a horizontal position and determine the pencil hardness of the sample by pushing a pencil with gradually increasing hardness on the sample. During the test, the pencil is fixed so that the pencil can press downward on the film surface at a 45° angle under a load of 750 g, and pencils of different hardnesses are slid on the film layer under a fixed pressure to observe whether there are indentations or scratches until it is found that the pencil will not cut or scratch the surface of the sample, and then obtain the pencil hardness.

[0041] Abrasion resistance test: Adopt the national standard "GB1768-79: Method for Determining the Abrasion Resistance of Paint Films" to conduct the abrasion resistance test. Use a reciprocating linear abrasion tester for detection, select steel wool as the abrasion medium, with a load of 1000 g, the grinding head reciprocates 60 times per minute, and continue for 1000 times to observe the surface condition of the sample.

[0042] The test results are shown in Table 1.

[0043] Table 1 Test Results

[0044] As can be seen from Table 1, compared with Comparative Example 1 using silica sol, Examples 1-6 using modified silica sol have varying degrees of improvement in transmittance, surface hardness, and abrasion resistance. Thus, it can be seen that the addition of modified silica sol can improve the transmittance, surface hardness, and abrasion resistance of optical lenses. At the same time, with the increase in the amount of modified silica sol added, the transmittance and surface hardness of the optical lenses are significantly enhanced. When the mixing ratio of epoxy acrylate to modified silica sol reaches 60:(18-20), the transmittance and surface hardness of the optical lenses show the best performance.

[0045] 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 preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the protection scope of the present invention.

Claims

1. A method for preparing an optical lens, characterized in that: include: Tripropylene glycol diacrylate and 3-aminopropyltriethoxysilane are added to tetrahydrofuran to carry out addition reaction to obtain acrylate triethoxysilane; Take ethyl orthosilicate and add it to the solvent, mix it evenly, then add hydrochloric acid, perform hydrolysis reaction, then add triethoxysilane acrylate, mix it evenly, then add acetic acid to perform polymerization reaction, and after aging, obtain modified silica sol; After removing the solvent from the modified silica sol, the modified silica sol is mixed with epoxy acrylate and a photocuring agent, coated on the lens body, and then photocured to obtain an optical lens.

2. The preparation method according to claim 1, characterized in that: The molar ratio of tripropylene glycol diacrylate to 3-aminopropyltriethoxysilane is 1:(0.8-1.2), the temperature of the addition reaction is 20° C.-30° C., and the time is 20 h-40 h.

3. The preparation method according to claim 1, characterized in that: The solvent includes ethanol and deionized water, the mass ratio of ethanol to deionized water is 1:(2-3), the temperature of the hydrolysis reaction is 30° C.-40° C., and the time is 1 h-2 h.

4. The preparation method according to claim 1, characterized in that: The mass ratio of the tetraethyl orthosilicate to triethoxysilane acrylate is 1:(1-2), the polymerization reaction temperature is 50° C.-60° C., and the reaction time is 4 h-5 h.

5. The preparation method according to claim 1, characterized in that: The mass ratio of the solvent, hydrochloric acid and acetic acid is 100:(1-3):(10-25).

6. The preparation method according to claim 1, characterized in that: The aging temperature is 20° C.-30° C., and the aging time is 3-5 days.

7. The preparation method according to claim 1, characterized in that: The mass ratio of the epoxy acrylate, the modified silica sol and the light curing agent is 60:(10-20):(3-6).

8. The preparation method according to claim 1, characterized in that: The photocuring agent is one of 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

9. The preparation method according to claim 1, characterized in that: The light curing is performed using a light curing machine, the time is 2 min-5 min, and the temperature is 20° C.-50° C.

10. The preparation method according to claim 1, characterized in that: The lens body is made of resin.

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