JPH02117976A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition excellent in scuffing resistance, dyeing property, adhesion, etc., and having a same-order refractive index as that of lens by blending a mixture of antimony oxide sol and silica sol with a silane coupling agent consisting of a specified three-component blend. CONSTITUTION:A mixture of an antimony oxide sol and silica sol of a ratio of (1:9)-(4:6) is blended with a three-component blend composed of 5-90wt.% gamma-glycidoxypropyltrimethoxysilane, 5-80wt.% gamma-glycidoxypropylmethyldimethoxysi lane and 5-50wt.% beta-(3,4-epoxycyclohexyl)ethyltrimethoxysilane as a silane coupling agent to provide an objective composition with about 1.5 refractive index useful as a hard coat for a plastic lens.

Description

Detailed Description of the Invention Field of Application J The present invention relates to a coating composition useful as a hard coat applied to plastic lenses having a refractive index of around 1.5, which forms a film having a refractive index similar to that of the lens. Regarding.

"Prior art and its problems" Diethylene glycol bisallyl carbonate resin (hereinafter referred to as CR-39) has good processability in terms of impact resistance, cutting properties, polishing properties, dyeing properties, etc. It has been widely used as a plastic lens substrate. A hard coat containing silica sol is used on this substrate made of CR-39. This group (the refractive index of the opposite is 1.5
However, even if silica sol is used, the refractive index is at most 1.
48, which caused interference fringes.

In addition, with such a hard coat, when it is vacuum-deposited after dyeing, discoloration occurs and the dyeing fading properties are poor, so there is a problem that dyeing must be carried out in anticipation of discoloration.

``Object of the Invention'' The present invention is capable of forming a hard coat film with a refractive index of 1.49 to 1.52, and has improved dyeing properties and dye fading resistance, and has excellent scratch resistance and resistance to substrates and vacuum-deposited films. An object of the present invention is to provide a coating composition that produces a hard meat film with excellent adhesion.

"Structure of the Invention" The present inventor has discovered that the refractive index of the hard coat film can be controlled by changing the mixing ratio of antimony oxide sol and silica sol, and that the performance can be improved by blending a specific silane coupling agent. The present invention was completed based on this knowledge.

That is, the coating composition according to the present invention comprises a mixture of antimony oxide sol and silica sol in a ratio of 1=9 to 4:6, and 5 to 90% by weight of γ-glycidoxypropyltrimethoxysilane as a silane coupling agent; It is characterized by containing a ternary mixture consisting of 5-80% by weight of T-glycidoxypropylmethyldimethoxysilane and 5-50% by weight of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

As mentioned above, the refractive index of the hard coat film is set to 1.49 to 1.49.
In order to increase the ratio to 52, it is necessary to mix antimony oxide sol and silica sol in a ratio of 1:9 to 4:6. Outside this range, the desired refractive index cannot be obtained.

When antimony oxide fine particles are blended into the coating composition, the refractive index is increased compared to the case of using only silica sol, and the dyeability and color fading properties are improved. The antimony oxide sol used in the present invention includes fine antimony trioxide and/or
Alternatively, antimony pentoxide is colloidally dispersed in water and/or an organic solvent such as alcohol. This sol may contain various surfactants, amines, and acids for the purpose of improving the dispersibility of the antimony oxide fine particles.

Furthermore, the silica sol used in the present invention is one in which silicon dioxide fine particles are colloidally dispersed in water and/or an organic solvent such as alcohol. Silica sol exhibits weak acidity, but antimony oxide sol used in combination in the present invention is a stable sol that is neutral or weakly alkaline. It is preferable to use the silica sol and the antimony oxide sol at the same pH.

The coating composition of the present invention further comprises 5 to 90% by weight of γ-glycidoxypropyltrinotoxysilane, T-
Glycidoxypropylmethyldimethoxysilane 5-80
% by weight and a silane coupling agent consisting of 5-50% by weight of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

T-glycidoxypropyltrimethoxysilane affects the scratch resistance and adhesion to the deposited film, and if the amount is less than 5% by weight of the total amount of the silane coupling agent, the scratch resistance and the adhesion to the deposited film will be affected. If the amount exceeds 90%, the dyeability and adhesion to the substrate will decrease. In addition, T-glycidoxypropylmethyldimethoxysilane affects the dyeability and adhesion to the deposited film, and if the amount added is less than 5% by weight of the total amount of the silane coupling agent, the dyeability and the adhesion to the deposited film will be affected. If the amount exceeds 80% by weight, the scratch resistance and the adhesion to the substrate will decrease. Furthermore, β-(3
,4-epoxycyclohexyl)ethyltrimethoxysilane affects the adhesion to the substrate and the scratch resistance, and if the blended amount is less than 5% by weight of the total amount of the silane coupling agent, the adhesion to the substrate will be affected. If the content exceeds 50% by weight, the dyeability and adhesion to the deposited film will decrease.

The three components of the above-mentioned silane coupling agent can be used after being hydrolyzed in whole or in part.

By using a silane coupling agent containing the above three components in the above proportions, the present invention provides a hard coat with a good balance of scratch resistance, dyeability, adhesion to substrates, and adhesion to vacuum deposited films. is obtained.

Various curing agents can be further added to the coating composition of the present invention in order to accelerate curing. There are no particular restrictions on the curing agent that can be used, and examples include organic amines, metal acetylacetonates such as aluminum acetylacetonate and chromium acetylacetonate, and organic acid metal salts such as sodium acetate, zinc naphthenate, and cobalt naphthenate. can be mentioned. Among these, aluminum acetylacetonate is particularly preferred.

Additionally, the coating compositions of the present invention contain additives commonly used in hard coat compositions, such as surfactants,
It may contain ultraviolet absorbers, antioxidants, and organic polymer compounds such as epoxy resins and acrylic resins for the purpose of improving hardness.

In the coating composition of the present invention, the mixing ratio of the silane coupling agent and the sol mixture is 1:0.5 to 5.

In addition, the above silane coupling agent is present in the hard coat film formed when the coating composition of the present invention is applied in an amount of 4 to 45% by weight, preferably 16 to 36% by weight, and the sol mixture is present in an amount of 1 to 30% by weight. % by weight, preferably 4-24
% by weight. When the amount of the silane camping agent increases, the refractive index decreases, the scratch resistance decreases, and the dye fading resistance deteriorates. If there is too much antimony oxide, cranks will form and the film will turn white.

When applying the coating composition of the present invention, it is preferable to dilute it with various solvents from the viewpoint of workability and control of coating thickness. Examples of the diluting solvent include water, alcohol, ester, ether, halogenated hydrocarbon, dimethylformamide, dimethyl sulfoxide,
Examples include aromatic hydrocarbons, aliphatic hydrocarbons, ketone compounds, organic acids, etc., and a mixed solvent of these may be used if necessary. Considering the dispersibility of antimony oxide and silica, water, alcohols, dimethylformamide,
Ethylene glycols, organic acids, etc. are preferred.

The method for applying the coating composition to the lens substrate is not particularly limited, and various methods such as brush coating, dipping, roll coating, spray coating, spin coating, and flow coating can be applied.

When applying the coating composition of the present invention, it is applied onto a lens substrate to a film thickness of 1 to 10 μm, preferably 1.5 to 5 μm.

A lens provided with a heart coat film using the coating composition of the present invention is thus suitably dyed, and then an antireflection film can be applied to the lens by vacuum deposition, with fewer than 18 colors.

Inorganic substances that can be used to provide the anti-reflection coating by vacuum deposition include various oxides, halides and sulfides, such as MgF2, SiO2, Affi20.
．． ,CeF,,The2,Z r Oz,Ce Oz,
Ti0z, Nb2O5, Tag's, Y2O3, Yb,
03, ZnS, etc.

"Examples of the Invention" Next, the present invention will be described in more detail based on Examples, but the present invention is not limited thereto.

Example 1 5 parts by weight of 0.01N hydrochloric acid to 15 parts by weight of T-glycidoxypropyltrimethoxysilane, 22.5 parts by weight of o, oi normal hydrochloric acid to 90 parts by weight of T-glycidoxypropylmethyldimethoxysilane. Furthermore, 12 parts by weight of 0.1N hydrochloric acid and 4 parts by weight of ethyl alcohol were mixed with 45 parts by weight of β-(3,4-evogycyclohexyl)ethyltrimethoxysilane, hydrolyzed, and 20°
Stir at C for 16 hours.

Duneel FSN was added to the resulting mixture as a surfactant.
(Dupont Ceremony) 1.5 parts by weight, 2 parts by weight of aluminum acetylacetonate as a hardening agent, 1.4 parts by weight as a solvent
- 35 parts by weight of dioxane, 35 parts by weight of methanol, 35 parts by weight of isobutyl alcohol, and others Denacol EX
146 (epoxy resin manufactured by Nagase Sangyo Co., Ltd.), 75 parts by weight of methanol-dispersed antimony oxide sol (manufactured by Nissan Chemical Co., Ltd.), and 300 parts by weight of methanol-dispersed silica sol were added and mixed to prepare a coating composition.

The above coating composition was applied to a CR-39 resin lens substrate with a refractive index of 1.5 to a thickness of 3 μm and cured at 120° C. for 3 hours to form a hard coat film.

Separately, a lens was manufactured in which an antireflection film consisting of layers of Y z O:l, ZrO□, and Sing, each having an optical thickness of λ/4, was attached in order from the substrate by vacuum evaporation on the above hard coat film.

Performance evaluations were conducted for lenses with only a hard coat film and lenses with an additional antireflection film. The results are shown in Table 1.

Examples 2 to 4 Coating compositions were prepared in the same manner as in Example 1, except that the blending amounts of the silane coupling agent, antimony oxide sol, and silica sol were changed as shown in Table 1. Lenses and lenses with antireflection films were produced, and the results of performance evaluation are shown in Table 1.

Note that performance evaluation was performed by the following method.

b) Scratch-resistant steel wool #0000 is manually rubbed back and forth on the film surface 100 times to examine the state of scratches, and visually evaluated according to the following criteria.

O: There are almost no scratches on the film surface.

△: There were some scratches on the film surface.

×: The film surface was deeply scratched.

11 parallel lines are drawn on the surface of the adhesive film using a knife or the like at 1 mm intervals to form 100 squares. A cellophane adhesive tape is firmly pasted on top of the tape, rapidly peeled off in a 90 degree direction, and the number of squares remaining out of 100 is determined and evaluated using the following criteria.

Evaluation is based on the average of 3 times of peeling.

○: 95/loo or more X: 94/100 or less
After immersion for 0 minutes, the light attenuation rate at 550 nm was measured and evaluated based on the following criteria.

○: Attenuation rate 3 △: Attenuation rate 2~30 be.

×: Light attenuation rate less than 20% - poor dyeability.

2) Interference fringes Evaluation was performed visually with the naked eye according to the following three categories.

A: No interference fringes are seen.

B: Three interference fringes are visible.

C: Crimson interference fringes are clearly seen.

e) Dyeing and fading After hard coating, dye and measure the color tone brightness with a color meter.After vacuum deposition, measure the color tone brightness again with a color meter. Calculate the color difference (ΔE) before and after vapor deposition.

○: ΔE = 0. Δ less than 5: 8E = 0. 5 to 1.0 ×: ΔE = 1. 0 or more In the table, T-glycidoxypropyltrimethoxysilane is the A component, γ-glycidoxypropylmethyldimethoxysilane is the D component, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane is the C component. show.

Table 1 Comparative Examples 1 to 4 A coating composition was prepared in the same manner as in Example 1, except that a silane coupling agent, antimony oxide sol, and silica sol were used in the formulations shown in Table 2 below, and a hard coat was further prepared. A lens with a film and a lens with an antireflection film were produced, and the results of performance evaluation are shown in Table 2.

"Effects of the Invention" As described above, in the coating composition according to the present invention, the refractive index can be easily controlled by adjusting the mixing ratio of antimony oxide sol and silica sol,
It produces a hard coat film that is excellent in all aspects of scratch resistance, dyeability, fading resistance, adhesion to substrates, and adhesion to vacuum-deposited films.

Further, the coating composition of the present invention has a coating composition of 1.49 to 1.
It has a refractive index of 52 and is suitable for hard coating of lenses made of diethylene glycol bisallyl carbonate resin or the like.

Patent applicant: Asahi Optical Industry Co., Ltd.

Claims (1)

[Claims] 1. Antimony oxide sol and silica sol 1:9 to 4:
6 and γ- as a silane coupling agent.
5-90% by weight of glycidoxypropyltrimethoxysilane, 5-80% by weight of γ-glycidoxypropylmethyldimethoxysilane and 5-50% by weight of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. A coating composition comprising a mixture of components. 2. The coating composition according to claim 1, wherein the silica sol and the antimony oxide sol are used at the same pH. 3. The coating composition according to claim 1, which forms a hard coat having a refractive index of 1.49 to 1.52.