JPS6257961B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to novel optical components, particularly novel organic synthetic polymer lenses with deposited transparent abrasion resistant coatings and novel methods for making the coated optical components.

Description of the Prior Art Various methods have been proposed in the past for improving the surface properties and scratch resistance of solid organic polymers, particularly transparent polymeric materials. U.S. Patent No. 2404426 and No.
No. 2,404,357 discloses the use of ethyl silicate to coat synthetic polymers, particularly methyl methacrylate polymers. This ethyl silicate has been shown to combine with moisture during drying, baking or aging operations and to be crosslinked by using amines.

Abrasion resistant coatings are also disclosed in U.S. Pat. No. 3,700,487, which shows a polycarbonate substrate coated with lightly crosslinked polyvinyl alcohol, and in U.S. Pat. No. 3,484,157, which shows a polycarbonate substrate coated with a directly applied A transparent abrasion resistant plastic optical component having a coating is disclosed, the coating comprising a vinyl polymer crosslinked with a dialdehyde crosslinker.

Among previous attempts to obtain abrasion-resistant coatings, it has been difficult to obtain good abrasion-resistant coatings by application using aqueous solutions by dipping operations in which coatings are applied to synthetic organic base materials in appreciable thickness. It resulted in a failure. Conventional coatings are limited to relatively thin coatings, ie, about 1 micron. Coatings by spin coating methods known to those skilled in the art are limited in the thickness of the coating that can be applied in a single operation. These two problems are solved by the methods and compositions of the present invention. Good abrasion resistance is obtained by using relatively thick coatings on synthetic organic polymeric substrates. The methods and compositions of the present invention also overcome the discoloration problem of conventional coatings applied as a continuous layer. The distinct yellow color of conventional coatings is particularly undesirable for optical components.

US Pat. No. 3,986,997 describes pigment-free coating compositions which are used in particular to obtain abrasion-resistant coatings for optical materials. This patent does not describe the bond coat of the present invention or similar bond coats. Example 6 of this patent specification is
The use of a bond coat made by soaking the substrate overnight in a 10% solution of potassium hydroxide or by priming the substrate with a silane-modified epoxy primer is shown. Although not described in this patent specification, careful control of humidity during coating of optical components by this patented method is necessary to produce a product with commercially acceptable optical properties.

SUMMARY OF THE INVENTION The present invention provides plastic optical substrates, particularly polycarbonate lenses for eyeglasses and polydiethylene glycol bisallyl carbonate lenses for eyeglasses, using organoalkoxysilanes of the formula AR ₁ Si (OR ₂ ) _a (R ₃ ) _b (OH) _c . A coating method is obtained in which A is NH ₂ , NHR ₃ or NHR ₂ NH ₂ when the lens is polycarbonate, or CH ₂ CH- when the lens is polydiethylene glycol bisallyl carbonate; R ₁ is alkylene having 2 to 10 carbon atoms, R ₂ and R ₃
is alkyl having 1 to 4 carbon atoms, a is 0, 1 or 2, b is 0, 1 or 2, c is 1, 2 or 3, and a+b+c=3. A suitable bond coat for polycarbonate lenses is commercially available Υ-aminopropyltriethoxysilane. This material is known as Union Carbide under the trade name A-1100.
A related material is commercially available from Dow _Corning (Dow _Corning ) under _the trade name Z- _{6020 ,} which has _{the formula}
-Commercially available from Corning. These materials are known binders for laminates of polycarbonate and glass, such as glass fibers or glass sheets. For polydiethylene glycol bisallyl carbonate lenses (trade name: CR-39), bond coatings with epoxy reactive groups are preferred. An example of this material is Union Carbide's product A-187.
and Z-6040, a product of Dow Corning. Both of these materials are Υ -glycidoxypropyltrimethoxysilane.

This bond coat is applied in a conventional manner from a dilute solution, usually containing less than 20% active substance. This bond coat application should be carried out in a manner known to those skilled in the art that yields a coating of the minimum effective thickness. The thickness of the coating was not measured but is believed to be between 1 and 10 molecules in size. One preferred solution used for dipping is 10% Υ -aminopropyltriethoxysilane, 85% ethyl alcohol and 5%
Composed of % water. A suitable coating thickness is obtained by soaking the lens in this solution for about 1 minute.
However, it has been discovered that good coatings can be obtained with soaking times of 1 minute or more.

U.S. Pat. No. 3,986,997 discloses coating compositions and numerous examples of uses. These coating compositions are commercially available from Dow Corning under the trade names ARC and C-RESIN. The November/December 1976 issue of MATERIAL NEWS includes an award paper for this excellent new industrial product.

Example 1: Injection molded polycarbonate lenses meeting eyeglass quality standards were prepared using 10% Υ-aminopropyltriethoxysilane, 85% ethyl alcohol and 5% ethyl alcohol.
1% at room temperature in a bond coating solution consisting of 1% water.
Soaked for minutes. The lens was then removed from the silane solution, washed with water, and dried.

The immersion time in the silane solution is not particularly limited. Similarly, there is no limit to the time between removing the lens from the silane solution and cleaning. In practice, the lens may be dried before cleaning. However, a delay of one day or more may cause the finished coating to be unduly thick and may also produce undesirable haze.

A water rinse following silane solution soaking was found to be absolutely necessary to remove haze from the coating. This clouding is not desirable for eyeglass lens products, so washing with water is highly desirable. However, for products that limit the transmission of light, such as sunglasses, such fogging is not a drawback and bath cleaning is optional.

The thickness of the bond coat is not limited since only the molecules that have reacted with the polycarbonate substrate, or the silane molecules that have reacted with the reactants, remain as part of the coat after washing with water. Thick coatings that affect lens fogging are undesirable.

The lens was then coated with an abrasion resistant coating material under the trade name C-RESIN. This material is covered by U.S. Patent No.
It is described in the specification of No. 3986997. This material was applied to lenses using a solution dipping method. After receiving, C-
The lens was placed in a container through RESIN, immersed in it, and pulled up at the speed limit. The pulling speed of the lens limits the coating thickness. The lens lifting speed can be varied from 2.54 cm per minute to 50.8 cm per minute. The preferred pulling speed is per minute.
It is on the order of 10.16cm to 25.4cm. The lens in this example was pulled up at a rate of 19.05 cm per minute. The lens was then processed at room temperature. After drying,
The lenses were cured in a circulating air oven at 121°C for 8 hours. The properties of this lens, namely abrasion resistance, fogging and thermal shock resistance, are determined by the abrasion resistant coating material (C-
RESIN) applied to the lens under conditions of controlled humidity, ie, 30% relative humidity or less, was nearly equivalent to similarly coated polycarbonate lenses.

Example 2 A second group of polycarbonate lenses was treated with the bond coating solution set forth in Example 1. After washing and drying, attach the bonded coating to the lens (ARC (product name)).
It was immersed in the composition and withdrawn at a controlled rate of 19.05 cm per minute. The coated lenses were then dried at room temperature and then placed in a circulating air oven at 121°C for 8 hours. This lens has good properties for ophthalmic use and similar properties to the lens described in Example 1, with abrasion resistance, fogging and thermal shock resistance compared to similarly coated lenses in a humidified environment. It was almost the same.

Polycarbonate lenses coated as described in U.S. Pat. % or less relative humidity), the same degree of adhesion will occur.

Example 3 A CR-39 ophthalmic lens was placed 10% in an aqueous ethanol mixture containing 17 parts of ethyl alcohol to 1 part of water and adjusted to a pH of 3 to 5 with the addition of acetic acid.
The sample is immersed in a solution containing Υ-glycidoxypropyltrimethoxysilane for about 1 minute. After removing the lens, wash it with water and dry it. CR-39 bond coated lenses were prepared with abrasion resistant ARC following the procedure in Example 2.
The coating material is applied, dried and cured.

Claims (1)

[Claims] 1. A spectacle lens selected from the group consisting of a polycarbonate lens and a polydiethylene glycol bisallyl carbonate lens; formula AR ₁ Si
Bonded coating with (OR ₂ ) _a (R ₃ ) _b (OH) _c , where A is NH ₂ if the lens is polycarbonate;
In NHR ₂ or NHR ₁ NH ₂ , when the lens is polydiethylene glycol bisallyl carbonate, A is [Formula], R ₁ is alkylene having 2 to 10 carbon atoms, R ₂ and R ₃ are 1 to 4 Alkyl having the number of carbon atoms, a is 0, 1 or 2, b is 0, 1 or 2, c is 1, 2 or 3 and a+
b + c = 3, consisting of a combination of a bond coat reacted with the lens according to A above; and an abrasion resistant coating obtained by dipping the lens with the bond coat in a pigment-free aqueous coating composition. In wear-resistant lenses, the aqueous coating composition described above has the formula RSi
(OH) ₃ silanol, R is an alkyl group having 1 to 3 carbon atoms, a vinyl group, 3,3,3-
selected from the group consisting of trifluoropropyl group, Υ-glycidoxypropyl group and Υ-methacryloxypropyl group, and at least 70% by weight
It consists of a dispersion containing colloidal silica in a lower aliphatic alcohol-aqueous solution of a partial condensate of silanol, CH ₃ Si (OH) ₃ , and the composition comprises 10 to 70% by weight of colloidal silica and 30 to 90% by weight of colloidal silica. A wear-resistant lens containing 10 to 50% by weight of solids consisting of a partial condensate, and the wear-resistant coating reacted with the OH of the bonding coating. 2 The lens is polycarbonate and the bonding coating is Υ-
The wear-resistant lens according to claim 1, which is aminopropyltriethoxysilane. 3. The wear-resistant lens according to claim 2, wherein the wear-resistant coating is C-RESIN (trade name). 4. The wear-resistant lens according to claim 1, wherein the wear-resistant coating is an ARC (trade name) coating.