KR20090080644A - Hard Coating Solutions For Plastic Lens And Preparation Method Thereof - Google Patents

Abstract

A method for manufacturing a hard coating solution for a plastic lens, and the hard coating solution for a plastic lens prepared by the method are provided to obtain a high refractive index, an excellent surface hardness, an excellent adhesion and a high transmissivity. A method for manufacturing a hard coating solution for a plastic lens comprises the steps of reacting a titanium alkoxide and water in an alcohol solvent to prepare a titania nanosol in which the anatase or rutile nanoparticle having an average particle diameter of 1 ~ 50 nm is dispersed; and mixing a silane coupling agent, an alcohol and water with the nanosol to react them for 10 hours or more, thereby preparing a homogeneous solution.

Description

Hard Coating Solution For Plastic Lens And Manufacturing Method Thereof {Hard Coating Solutions For Plastic Lens And Preparation Method Thereof}

The present invention relates to a hard coating solution for a plastic lens and a method of manufacturing the same, and more particularly, by comprising a titania nanosol having anatase structure (see FIG. 1) and a silane coupling agent, and having high refractive index and surface strength. It relates to a hard coating solution for plastic lenses and a method for producing the same, which does not cause yellowing.

Transparent plastic materials have been widely used as a substitute for glass in many fields because of their light weight and good impact resistance. In particular, transparent plastic materials have been widely applied as eyeglass lenses or leisure goggles. However, most plastic materials have a soft surface, which is easily scratched by friction, and is poor in resistance to solvents and the like. Therefore, when the plastic material is used as it is, there is a disadvantage in that transparency is poor. In order to overcome these disadvantages, a hard coating is generally formed on the surface of a plastic material using an organic material or a silicone-based coating material.

Plastic spectacle lenses are currently being improved in a direction that can exhibit higher refractive indices in order to maintain a thinner thickness while maintaining the same optical properties. The refractive index of the highly refractive plastic spectacle lens is 1.60, which is quite different from the refractive index of 1.46 to 1.48 of the conventional silicone hard coating. The presence of the interference pattern (rainbow pattern) due to the refractive index difference between the plastic spectacle lens and the hard coating agent seriously harms the appearance of the plastic lens and has a problem of lowering the product value. In order to solve this problem, the refractive index of the coating film by the hard coating agent should be improved to be similar to that of the spectacle lens.

Conventional techniques for improving the refractive index of the hard coating solution using a titanium alkoxide as a starting material for producing a high refractive index, the titanium alkoxide causes a rapid hydrolysis reaction with water, thereby controlling the rate of hydrolysis of titanium alkoxide To this end, chelating agents and inorganic titania components are added. In this case, in order to bond the chelating agent and the inorganic titania component to the organic plastic substrate, a silane coupling agent, a mixed solution of alcohol, water, and a catalyst has been used. However, when the hard coating solution prepared by the above method is coated on the plastic lens, a yellowing phenomenon occurs in which the color of the lens surface turns yellow, thereby causing a problem of severely damaging the appearance of the plastic lens.

In addition, another conventional technique for improving the refractive index of the hard coating solution is to add nanoparticles consisting of mixed metal oxides, such as titanium oxide, tin oxide, zirconium oxide, etc. in a coating solution made of silicon oxide to hydrolysis reaction and polycondensation Many methods of increasing the refractive index have been carried out by a sol-gel process involving a reaction. However, the nanoparticles made of the mixed metal oxide are difficult to control the size, and as a result, there is a disadvantage in that the light transmittance is lowered due to light scattering. This may act as a fatal disadvantage when applied to the spectacle lens requiring a high degree of transparency. In addition, the hard coating agent solution composed of such a mixture nanoparticles had a problem that the storage stability is poor.

Therefore, the present invention has been made to solve the above-mentioned conventional problems, the object of the present invention is to realize a light coating and high refractive index, but hard coating solution for plastic lenses that does not occur when coating on a plastic lens and its production It is to provide a method.

Another object of the present invention is to provide a hard coating solution for plastic lenses and a method of manufacturing the same, which have high refractive index and excellent surface hardness, adhesion, and storage stability and achieve high transmittance.

In order to achieve the above object, the present invention provides a titania nanosol prepared by producing a titanium alkoxide, which is a starting material for producing a high refractive index, and a hydrolysis and polycondensation reaction with water in an alcohol as a solvent. It consists of a silane coupling agent for adhering on a plastic substrate, which is an organic substance, and a mixed solution of alcohol, water, and a catalyst. Such a solution according to the present invention may be referred to as an organic-inorganic hybrid coating solution because it is for bonding inorganic titania nanoparticles onto an organic plastic substrate.

Method for producing a hard coating solution of the present invention is as follows. First, the titanium alkoxide is reacted in an alcohol as a solvent until it becomes a homogeneous solution in the presence of a catalyst acid and water to prepare a titania nano sol in which titania nanoparticles are dispersed. Next, the final coating solution is prepared by reacting the silane coupling agent with alcohol, water, and a catalyst.

Wherein the titania nano sol, as shown in Figure 1, (101), (004), (200), (105), (204), (220), (215) anatase characterized by the crystal plane (anatase) It can be seen that it has a) -type crystal structure.

And the particle size (diameter) of the titania nano sol represents a particle size distribution as shown in FIG. That is, the average particle diameter of the titania nano sol is distributed in the range of 1 to 50 nm. In this case, when the average particle diameter of the nanosol is less than 1 nm, the solution becomes a non-colloidal state, and when the average particle diameter exceeds 50 nm, there is a high possibility of cracking during coating on the lens.

Hereinafter, each component contained in the hard coating solution of the present invention will be described in detail.

(1) titanium alkoxide [Ti-Alkoxide; Ti (OC _n H _{2n +1} ) ₄ ]

It is used to increase the refractive index of the hard coating solution. Types of titanium alkoxide include titanium methoxide [Ti (OCH ₃ ) ₄ ], titanium ethoxide [Ti (OC ₂ H ₅ ) ₄ ], titanium propoxide [Ti (OC ₃ H ₇ ) ₄ ], titanium butoxide Side [Ti (OC ₄ H ₉ ) ₄ ] and the like may be used.

(2) silane coupling agent

The silane coupling agent is a substance added to adhere the titania nanoparticles, which is an inorganic material, on the plastic lens substrate, which is an organic material, and has the following general formula.

R ¹ _a R ² _b Si (OR ³ ) _{4- (a + b)}

Wherein R ¹ and R ² are each independently β- (3,4-epoxycyclohexyl) ethyl (β- (3,4-epoxycyclohexyl) ethyl) and γ-glycidoxypropyl , γ-methacryloxypropyl, γ-chloropropyl, γ-mercaptopropyl, or γ-aminopropyl group, R ³ Represents a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, methoxyethyl group, or 2-ethylhexyl group, and a and b represent the integer of 0-3.

In addition, the silane coupling agent may be used alone or in combination of two or more kinds to compensate for the disadvantages of the respective silane coupling agents.

On the other hand, the dose of such silane coupling agent is in the range of 0.1 to 10 moles with respect to 1 mole of titanium alkoxide. If the content of the silane coupling agent is less than 0.1 mole, the hardness of the lens surface during coating decreases, and if the content exceeds 10 moles, the adhesion and refractive index of the hard coating solution to the lens is reduced.

(3) alcohol

The alcohol used in the present invention may be used as a solvent for the hydrolysis reaction between the starting material titanium alkoxide and water, and serves to significantly improve the storage stability of the coating solution and the transparency of the coating film. Examples of such alcohols include methanol, ethanol, isopropyl alcohol, butanol, and the like, and the amount of the alcohol is in the range of 1 to 20 moles with respect to 1 mole of titanium alkoxide. If the alcohol content is less than 1 mole, the transparency of the coating film is not good, and if it exceeds 20 moles, the storage stability of the coating solution is greatly reduced.

(4) water

It is added to hydrolyze the titanium alkoxide in solvent to form titania nanosol. The addition amount of water is added in the range of 0.5-10 mol with respect to 1 mol of titanium alkoxides. When the amount of water is less than 0.5 mole, the refractive index of the coating film is not good, and when the amount exceeds 10 moles, the transparent nanosol is not formed and an opaque precipitate is obtained.

(5) catalyst

The catalyst used in the present invention serves to adjust the pH of the solution or control the reaction rate. Organic acids or inorganic acids are used for this purpose, and examples thereof include hydrochloric acid, nitric acid, acetic acid, p-toluenesulfonic acid, and the like. These acid components may be used alone or in combination of two or more in consideration of the reaction rate according to the final pH or component of the coating solution and the adhesion to the applied substrate.

When the hard coating solution of the present invention is applied to a plastic spectacle lens and heat treated, there is no yellowing, and a high refractive index and high hardness protective film can be obtained. In this case, the coating method is a roll coating, immersion coating, spin coating, spray coating, such as a variety of commonly used methods are applied. The curing conditions vary slightly depending on the composition of the solution and the type of plastic lens, but in general, the desired coating film can be obtained by first curing at 90 ° C. for 30 minutes in a drying oven and then curing at 120 ° C. for 2 hours. have.

According to the hard coating solution for a plastic lens according to the present invention and a method for manufacturing the same, yellowing does not occur when the plastic lens is coated, thereby achieving a light lens and a high refractive index, thereby obtaining a plastic lens having a beautiful appearance.

In addition, according to the present invention, by achieving a high transmittance with a high refractive index and excellent surface hardness and adhesion, there is an advantage that a high refractive index plastic lens excellent in durability, stability and light transmittance can be obtained.

In addition, according to the present invention, by excellent storage stability of the hard coating solution, even if the hard coating solution according to the present invention for a long time there is an effect that the performance is maintained as it is.

Hereinafter, the present invention will be described in detail with reference to Examples.

<Example 1>

While maintaining the temperature inside the reactor at 30 ℃ or less, Sigma Aldrich's titanium tetraisopropoxide 30g, isopropyl alcohol 40g, hydrochloric acid 1g was mixed and reacted for 5 hours to make a nanosol. Thereafter, 20 g of γ-glycidoxypropylsilane produced by Sigma Aldrich, 20 g of ethanol, 7 g of distilled water, and 1 g of hydrochloric acid were mixed with the nanosol, and reacted for 10 hours to form a homogeneous solution. The obtained final composition was immersed in a plastic spectacle lens (made by Daejin Optical Co., Ltd., refractive index 1.60), dried at room temperature for 10 minutes, first cured at 90 ° C for 30 minutes, and then cured at 120 ° C for 2 hours. The desired coating film was obtained.

<Example 2>

While maintaining the temperature inside the reactor at 30 ° C. or less, 30 g of titanium tetraisopropoxide manufactured by Sigma Aldrich and 30 g of ethanol were reacted for 1 hour to make a homogeneous solution. In addition, 10 g of γ-glycidoxypropylsilane from Sigma Aldrich, 10 g of aminopropylsilane, 20 g of ethanol, 7 g of distilled water, and 1 g of hydrochloric acid were mixed and reacted for 10 hours to prepare a uniform solution. The obtained final composition was immersed in a plastic spectacle lens (made by Daejin Optical Co., Ltd., refractive index 1.60), dried at room temperature for 10 minutes, first cured at 90 ° C. for 30 minutes, and then cured at 120 ° C. for 2 hours. The desired coating film was obtained.

<Example 3>

While maintaining the temperature inside the reactor at 30 ° C. or less, 30 g of titanium tetraisopropoxide manufactured by Sigma-Aldrich and 40 g of ethanol were reacted for 10 hours to prepare a homogeneous solution. In addition, 10 g of γ-glycidoxypropylsilane from Sigma Aldrich, 10 g of methyltriethoxysilane, 4 g of distilled water, and 1 g of hydrochloric acid were mixed, and then reacted for 10 hours to prepare a homogeneous solution. The obtained final composition was immersed in a plastic spectacle lens (made by Daejin Optical Co., Ltd., refractive index 1.60), dried at room temperature for 10 minutes, first cured at 90 ° C for 30 minutes, and then cured at 120 ° C for 2 hours. The desired coating film was obtained.

Experimental Example

Measurement of the physical properties of the coating film prepared in the embodiment of the present invention was performed by the following method.

(1) Storage stability test

Viscosity changes when stored at 25 ° C. for 3 months were evaluated, represented by A when the change in viscosity was insignificant, by B when the change was small, and by C when there was a significant change.

(2) Hot water resistance measurement

After dipping the specimen in which the coating film was formed in distilled water boiled at 100 ° C., immersed for 15 minutes, and taken out and dried, the water resistance was evaluated according to the ASTM D3359-87 method.

5B: There is no fall of the coating film at the cut edge, and there is no peeling of the coating film in the lattice.

4B: Deterioration of the edge is weakly observed and peeling occurs within 5% of the total.

3B: Peeling and brittleness of the edge part is observed and peels off within 15%.

2B: Even within the lattice, peeling and chipping are observed and peeled off within 35%.

1B: A large ribbon peeling is observed and peels at 35 to 65%.

0B: Peeled at an area of 65% or more (poor adhesion).

(3) impact resistance measurement

The impact resistance was evaluated by dropping a steel ball having a diameter of 150 mm having a diameter of 20 g at a height of 150 cm in a specimen in which a coating film was formed at room temperature. The same specimen was repeated three times.

O: Cracks do not occur or penetrate.

X: A crack occurs or penetrates.

(4) refractive index measurement experiment

The coating composition was spin-coated onto a silicon wafer of 2 cm on one side, and then cured. The coating composition was measured about 10 times for each part using an ellipsometer, which is a refractive index meter, to obtain an average value.

(5) Abrasion test (surface hardness test)

In a scratch test using # 0000 steel wool, the steel wool was cut to a size of 2.5 cm in width and contacted the test specimen with a load of 100 g, and rotated five times, and then visually observed.

AAA: No concentric scratches caused by steel wool were observed.

AA: One or two concentric circular scratches of steel wool were observed.

A: Five or less concentric circular scratches were observed in steel wool.

B: One or less concentric circular scratches by steel wool were observed in a circular pattern.

C: Two or more concentric scratches of steel wool were observed in a circular pattern.

(6) pencil hardness test (surface hardness test)

When the pencil was placed at a 45 ° angle on the plane of the coated specimen and pushed with a constant force, the hardness of the pencil was determined as the hardness of the surface when the scratched pattern or the coating film was not broken more than twice.

(7) light transmittance experiment

Based on the uncoated specimen, the light transmittance was measured with a spectrophotometer, and based on this, the light transmittance (% of transmittance) of the coated specimen was measured.

(8) coloring test

The lens coated with 0.2 wt% aqueous solution of BPI sun brown dye of Brain Powder Co., Ltd. was deposited at 90 ° C. for 5 minutes, and then the transmittance of the lens was measured.

(9) adhesion test

Eleven rows were cut with a knife on a second cured transparent coating film at intervals of 1 mm, 100 cells of 1 mm x 1 mm were made, and a cellophane tape having excellent adhesion was attached thereon, and then sharply separated to an angle of 180 °. This was repeated three times at the same location. The evaluation method is the same as the temperature resistance test.

division Comparative Example (No Coating) Example 1 Example 2 Example 3 Storage stability - A A A Hot water resistance - 4B 4B 4B Impact resistance - O O O Refractive index - 1.63 1.62 1.60 Scratch C A A AA Pencil hardness HB 7H 6H 6H Transmittance 85% (T) 90% (T) 90% (T) 90% (T) Coloring 60% (T) 61% (T) 60% (T) 60% (T) Adhesion - 5B 4B 5B Yellowing - Yellowing radish Yellowing radish Yellowing radish

As can be seen in Table 1, the coating composition prepared by the present invention has excellent storage stability, and has been improved to almost the same level of refractive index of the highly refractive plastic spectacle lens, and when coated on the plastic lens It can be seen that yellowing did not occur. In addition, it can be seen that not only excellent light transmittance, but also hot water resistance, impact resistance, scratch resistance, pencil hardness and adhesion that are factors related to the durability and stability of the coating composition. In addition, it can be seen that when the comparative examples regarding the colorability and the numerical values of Examples 1 to 3 are almost the same, the uncoated spectacle lens and the coating composition have the same coloring performance.

The rights of the present invention are not limited to the embodiments described above, but are defined by the claims, and those skilled in the art can make various modifications and adaptations within the scope of the claims. It is self-evident.

For example, although the embodiment of the present invention has been described with the focus on the spectacle lens, the present invention can be applied not only to the spectacle lens, but also to other lenses (for example, lenses used in telescopes and microscopes) in which transparent plastic is used. Do.

1 is a graph showing the X-ray diffraction (XRD) pattern of the powder dried titania nanosol prepared in the present invention,

Figure 2 is a graph showing the results of analyzing the particle size distribution of the titania nanosol prepared in the present invention by a dynamic light scattering device (DLS).

Claims (10)

Reacting titanium alkoxide and water in an alcohol solvent to prepare a titania nano sol in which anatase or rutile nanoparticles having an average particle diameter of 1 to 50 nm are dispersed; And And mixing a silane coupling agent with alcohol, water, and a catalyst in the nanosol and then reacting for 10 hours or more to prepare a uniform solution. The method of claim 1, The titanium alkoxide is a titanium methoxide, titanium ethoxide, titanium propoxide, titanium tetraisopropoxide, titanium butoxide, titanium butoxide production of the hard coating solution for the plastic lens, characterized in that any one of Way. The method of claim 1, The silane coupling agent is a manufacturing method of a hard coating solution for a plastic lens, characterized in that it has a general formula represented by the following formula. R ^One _a R ² _b Si ( OR ³ ) _{4- (a + b)} Provided that R ¹ and R ² are each independently β- (3,4-epoxycyclohexyl) ethyl, γ-glycidoxypropyl, γ-methacryloxypropyl, γ-chloropropyl, γ-mercapto Propyl or γ-aminopropyl group, R ³ represents methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, methoxyethyl group, or 2-ethylhexyl group, a and b are 0 to Represents an integer of 3. The method of claim 3, wherein the silane coupling agent is used alone or in combination of two or more. The method of claim 1, The alcohol is a method of manufacturing a hard coating solution for plastic lenses, characterized in that any one of methanol, ethanol, isopropyl alcohol, butanol. The method of claim 1, The silane coupling agent is a method for producing a hard coating solution for plastic lenses, characterized in that added to 0.1 to 10 moles with respect to 1 mole of titanium alkoxide. The method of claim 1, The alcohol is a method for producing a hard coating solution for plastic lenses, characterized in that added to 1 to 20 moles per 1 mole of titanium alkoxide. The method of claim 1, The water is a method for producing a hard coating solution for plastic lenses, characterized in that the addition of 0.5 to 10 moles per 1 mole of titanium alkoxide. The method of claim 1, The hard coating solution is a method of manufacturing a hard coating solution for a plastic lens, characterized in that by using a catalyst to adjust the pH of the solution or to promote the reaction. A hard coating solution for plastic lenses, characterized in that it is prepared according to any one of claims 1 to 9.

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