KR20080023016A - Preparation method of high refractive index hard coating solutions for plastic ophthalmic lenses - Google Patents

Abstract

A method for preparing a hard coating solution for a plastic glasses lens, and a hard coating solution prepared by the method are provided to improve storage stability, surface hardness and permeability and to increase refractive index. A method for preparing a hard coating solution for a plastic glasses lens comprises the steps of reacting a titanium alkoxide and a chelating agent to prepare a homogeneous solution; reacting a silane coupling agent, an alcohol, water and a catalyst to another homogeneous solution; and mixing the two homogeneous solutions and reacting it at a room temperature for 24 hours. Preferably the titanium alkoxide is any one selected from titanium methoxide, titanium ethoxide, titanium tetraisopropoxide, titanium butoxide and titanium t-butoxide.

Description

Preparation method of high refractive index hard coating solution for plastic spectacle lens and hard coating solution prepared thereby. {Preparation method of high refractive index hard coating solutions for plastic ophthalmic lenses}

The present invention relates to the preparation of a coating solution for plastic spectacle lenses excellent in high refractive index and surface strength, and a hard coating solution prepared thereby. More specifically, the present invention relates to a method for preparing an organic-inorganic hybrid coating solution composed of titanium alkoxide and a silane coupling agent, and a hard coating solution prepared thereby.

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 has the disadvantage of being easily scratched. 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 now being improved in such a way that they can exhibit higher refractive indices in order to have the same optical properties at thinner thicknesses for lighter weight. The refractive index of the highly refractive plastic spectacle lens is about 1.60, which is quite different from the refractive index of 1.46 to 1.48 of the conventional silicone hard coating agent. Accordingly, the presence of the interference fringes (rainbow fringes) due to the difference in refractive index severely harms the appearance of the plastic lens and degrades the product value. In order to solve this problem, the refractive index of the coating film should be improved to be similar to that of the lens.

Conventional techniques for improving the refractive index of hard coating solutions include hydrolysis and polycondensation reactions by adding nanoparticles made of mixed metal oxides such as titanium oxide, tin oxide, zirconium oxide, etc. to a coating solution made of silicon oxide. Many methods of increasing the refractive index have been performed by the sol-gel process.

However, the nanoparticles made of the above mixed metal oxides are difficult to control the size of the nanoparticles, and as a result, there is a disadvantage in that light transmittance decreases 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 solution composed of such nanoparticles has a problem that the storage stability is poor.

In addition, in the center chain of the organic compound, -O-, COO-, SS, -CO-S- and -CS-S- group are bonded to each other, and the terminal has reactive -SH group or -OH group. The method of chemically reacting a material having an unsaturated group with a silicon compound having an epoxy functional group by chemically reacting it with a sol-gel process to prepare a hard coating liquid having a high refractive index during curing has a disadvantage in that weather resistance and surface hardness decrease. There are problems in controlling the refractive index and transparency, high hardness, weather resistance and work efficiency.

The present inventors have found that the above-mentioned problems can be solved by preparing an organic-inorganic hybrid coating solution composed of titanium alkoxide and a silane coupling agent, and completed the present invention.

In order to solve the above problems, an object of the present invention is to provide a method for producing a hard coating solution having excellent storage stability, high refractive index and excellent surface hardness and high permeability, and a hard coating solution prepared thereby.

In order to achieve the above object, the present invention provides a titanium alkoxide having high refractive index and a chelating agent and an inorganic titania component added to control the hydrolysis reaction rate of titanium alkoxide because it causes a rapid hydrolysis reaction with water. It consists of a silane coupling agent for adhering on a plastic substrate and a mixed solution of alcohol, water and a catalyst.

Method for producing a hard coating solution of the present invention is as follows. First, titanium alkoxide is reacted with a certain mole number of chelating agent until it becomes a homogeneous solution. Next, another homogeneous solution is prepared by reacting the silane coupling agent with alcohol, water, and a catalyst. Thereafter, the two homogeneous solutions are mixed and reacted for a predetermined time to give an appropriate ripening time.

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

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

It is used to increase the refractive index of hard coating solution. Types of titanium alkoxides include titanium methoxide [Ti (OCH ₃ ) ₄ ], titanium ethoxide [Ti (OC ₂ H ₅ ) ₄ ], and titanium tetraisopropoxide [Ti (OCH (CH ₃ ) ₄ )]. , Titanium butoxide [Ti (OC ₄ H ₉ ) ₄ ], titanium tert-butoxide may be used.

(B) chelating agents

Titanium alkoxides are added to avoid this as they undergo a rapid hydrolysis reaction with water, causing precipitation. Examples of the chelating agent include acetylacetone (CH ₃ COCH ₂ COCH ₃ ), a dicarbonyl compound, ethyl acetoacetate (CH ₃ COCH ₂ COOC ₂ H ₅ ), and triethanolamine based on alkanolamine {N (CH ₂ CH ₂ OH ₃ }, diethanolamine {HN (CH ₂ CH ₂ OH) ₂ }, monoethanolamine {H ₂ N (CH ₂ CH ₂ OH)} and the like. The addition of the chelating agent is in the range of 1 to 10 moles per 1 mole of titanium alkoxide. If the content of the chelating agent is less than 1 mole, the role of the chelating agent may not be sufficient, and precipitation may occur during the hydrolysis reaction with water. If the content of the chelating agent exceeds 10 moles, the storage stability may be lowered.

(C) Silane coupling agent

The silane coupling agent is a substance added to adhere the titanium compound, which is an inorganic substance, on the plastic lens substrate, which is an organic substance, and has a general formula as shown in the following formula (1).

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

[Wherein R ¹ and R ² are each independently β- (3,4-epoxycyclohexyl) ethyl {β- (3,4-epoxycyclohexyl) ethyl}, γ-glycidoxypropyl, and γ -Methacryloxypropyl (γ-methacryloxypropyl), γ-chloropropyl (γ-chloropropyl), γ-mercaptopropyl (γ-mercaptopropyl), or γ-aminopropyl group (γ-aminopropyl) represents, R ³ is a methyl group , 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.]

The dosage of the silane coupling agent is in the range of 0.1 to 10 moles per 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 falls, and if it exceeds 10 moles, the adhesion and refractive index of the hard coating solution to the lens falls.

(D) alcohol

The alcohol used in the present invention acts to remarkably improve the storage stability 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.

(E) water

It is added to hydrolyze the titanium alkoxide. 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 it exceeds 10 moles, the surface hardness and adhesion of the coating film are degraded.

(F) 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 as described above is applied to a plastic spectacle lens and heat treated, a protective film having high refractive index and high hardness 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 is applied. The curing conditions are somewhat different depending on the composition of the solution and the type of plastic lens. Generally, the primary coating is cured for 30 minutes at 60 ^o C in a drying oven and then cured for 2 hours at 120 ^o C for 2 hours. You can get it.

Hereinafter, the present invention will be described in detail with reference to Examples. The following Examples are presented to explain the present invention, but the present invention is not limited thereto.

<Example 1>

While maintaining the temperature inside the reactor below 30 ^o C 30g of sigma aldrich titanium tetraisopropoxide and 40g of acetylacetone were reacted for 1 hour to make a homogeneous solution. In addition, 70 g of γ-glycidoxy propyl from Sigma Aldrich, 20 g of ethanol, 7 g of distilled water, and 0.1 g of hydrochloric acid were mixed and reacted for 1 hour to prepare a homogeneous solution. Then, the two solutions were mixed and reacted at room temperature for 24 hours to prepare a yellow coating solution. The obtained final composition was immersed in a plastic spectacle lens (Daejin Optical Co., Ltd. refractive index 1.60), dried at room temperature for 10 minutes, first cured at 60 ^° 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 below 30 ^o C 30g of sigma aldrich titanium tetraisopropoxide and 30g of acetylacetone were reacted for 1 hour to make a homogeneous solution. In addition, 25 g of γ-glycidoxy propyl from Sigma Aldrich, 20 g of ethanol, 7 g of distilled water, and 0.1 g of hydrochloric acid were mixed and reacted for 1 hour, thereby making a uniform solution. Then, the two solutions were mixed and reacted at room temperature for 24 hours to prepare a yellow coating solution. The obtained final composition was immersed in a plastic spectacle lens (Daejin Optical Co., Ltd. refractive index 1.60), dried at room temperature for 10 minutes, first cured at 60 ^° 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 below 30 ^o C 30g of sigma aldrich titanium tetraisopropoxide and 40g of acetylacetone were reacted for 1 hour to make a homogeneous solution. In addition, 25 g of γ-glycidoxy propyl from Sigma Aldrich, 20 g of ethanol, 4 g of distilled water, and 0.1 g of hydrochloric acid were mixed and reacted for 1 hour, thereby making a uniform solution. Then, the two solutions were mixed and reacted at room temperature for 24 hours to prepare a yellow coating solution. The obtained final composition was immersed in a plastic spectacle lens (Daejin Optical Co., Ltd. refractive index 1.60), dried at room temperature for 10 minutes, first cured at 60 ^° 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 Examples 1 to 3 was performed by the following method.

1) Storage Stability Test

Viscosity changes after three months of storage at 25 ^o C were evaluated, with A as the minor change in viscosity, B as the small change, and C as the 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 in 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 and a diameter of 20 g at a height of 150 cm at a temperature of 150 cm 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 made into contact with the test specimen with a load of 100 g, rotated five times, and visually observed.

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

AA: One or two concentric circular scratches caused by 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) Transmittance Experiment

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

8) Chromaticity Experiment

The lens coated on 0.2 wt% aqueous solution of BPI sun brown dye of Brain Powder Co., Ltd. was dipped 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 adhesive strength was attached thereon, and was rapidly detached 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 X O O O Refractive index - 1.60 1.64 1.63 Scratch C A A AA Pencil hardness HB 6H 6H 6H Transmittance 85% (T) 90% (T) 90% (T) 90% (T) Coloring 60% (T) 61% (T) 60% (T) 60% (T) Adhesion - 4B 4B 4B

As can be seen in Table 1, the coating composition prepared according to the present invention has excellent storage stability, scratch resistance, pencil hardness, and high refractive index and transmittance. It was found to be excellent and form a high refractive index and excellent surface hardness and high transmittance.

As described above, the present invention is excellent in storage stability, and has the effect of providing a hard coating solution having high refractive index and excellent surface hardness and high transmittance.

Claims (11)

1) preparing a homogeneous solution by reacting titanium alkoxide and a chelating agent; 2) preparing another homogeneous solution by reacting the silane coupling agent with alcohol, water and a catalyst; 3) preparing a coating solution by mixing the homogeneous solution prepared in steps 1) and 2) for 24 hours at room temperature; Method for producing a hard coating solution for plastic eyeglass lenses comprising a. The method of claim 1, Wherein the titanium alkoxide is titanium methoxide, titanium ethoxide, titanium tetraisopropoxide, titanium butoxide, titanium tert-butoxide, the manufacturing method of the hard coating solution for plastic spectacle lens, characterized in that any one. The method of claim 1, The silane coupling agent has a general formula represented by the following formula (1): a method for producing a hard coating solution for plastic spectacle lenses. R ^One _a R ² _b Si (OR ³ ) _{4- (a + b)}    (One) Wherein R ¹ and R ² are each independently β- (3,4-epoxycyclohexyl) ethyl, γ-glycidoxypropyl, γ-methacryloxypropyl, γ-chloropropyl, γ-mercaptopropyl, Or a 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, a and b represent 0-3 Represents an integer. The method of claim 1, The chelating agent is any one of acetyl acetone, ethyl acetoacetate, triethanolamine, diethanolamine, monoethanolamine, characterized in that the manufacturing method of the hard coating solution for plastic eyeglass lenses. The method of claim 1, The alcohol is a method of manufacturing a hard coating solution for plastic spectacle 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 spectacle 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 chelating agent is a method for producing a hard-coating solution for plastic eyeglass lenses, characterized in that added to 1 to 10 moles per 1 mole of titanium alkoxide. The method of claim 1, The alcohol is a hard coating solution for plastic spectacle lens, characterized in that added to 1 to 20 moles with respect to 1 mole of titanium alkoxide. The method of claim 1, The water is a method of producing a hard coating solution for plastic spectacle 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 for plastic spectacle lenses is a method of manufacturing a hard coating solution for plastic spectacle lenses, characterized in that by using a catalyst to adjust the pH of the solution or promote the reaction. A hard coating solution for plastic spectacle lenses, which is prepared according to any one of claims 1 to 10.