JPH0334041B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel plastic lens made of polyurethane as a resin material. There are a wide variety of plastic lenses, including magnifying glasses, magnifying glasses, spectacle lenses, polarized lenses, photochromic lenses, Fresnel lenses, and contact lenses. In the past, most eyeglass lenses were made of inorganic glass, but as sunglasses and fashion glasses became more popular for children and elderly eyeglass wearers, the safety of eyeglass lenses became more and more important. As people began to reconsider weight reduction, the use of plastic eyeglass lenses became more popular. Common resin materials currently used for plastic lenses include, for example, diglycol diallyl carbonate resin, methacrylic resin, and polycarbonate. These plastic resin optical materials have transparency comparable to inorganic glass and have excellent impact resistance. Although it has several advantages over inorganic glasses, there are still issues that need to be considered in the future. One of these is further improvement in abrasion resistance and durability such as heat crack resistance, and this durability is particularly important for prescription lenses. The second goal is the development of lens molding technology that is free from molding distortion and has excellent optical uniformity. Even more important is the development of materials with high refractive index and low dispersion, which are advantageous for lens design. These optical properties make it possible to reduce the thickness of the lens, leading to great commercial value in practical terms. In addition, since improving impact resistance and rigidity is also important in developing thin lenses, we should also focus on approaches that improve these properties. On the other hand, fluctuations in performance are a particular problem with contact lenses. That is, the refractive index, size, transparency, etc. of a contact lens change depending on the external environment when the contact lens is worn, resulting in various visual changes. Furthermore, in U.S. Patent No. 3,553,174,
By polymerizing organic polyisocyanate and hydroxyalkyl (meth)acrylate,
Techniques for obtaining transparent articles are presented. However, the articles obtained by this technique have a refractive index,
The problem was that the Atsube number was insufficient. In view of the above, an object of the present invention is to provide a plastic lens suitable for eyeglass lenses, contact lenses, etc., which has excellent impact resistance and toughness, and has a high refractive index and a high Abe's number. It is. The gist of the present invention is hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,6-diisocyanate caproic acid methyl ester (lysine diisocyanate methyl ester), 2-isocyanate ethyl-2,6-diisocyanate hexa at least one isocyanate compound selected from enoate, 1,6,11-undecane triisocyanate, and 1,4-butanediol, 1,
and at least one hydroxy compound selected from 12-dodecanediol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanol, polyethylene glycol, polypropylene glycol, trimethylolpropane, 1,2,6-hexanetriol, and sorbitol. The material is urethane resin obtained by reaction, and the refractive index n20℃ D=
It is a plastic cleanser with excellent transparency that satisfies 1.45 to 1.70. In the above, the wavelength of the refractive index is the value at 20° C. on the D line of 5892.9 Å. In the above, if the refractive index is too low, it is necessary to increase the lens thickness of the prescription lens, which causes problems in lens design. On the other hand, if the refractive index is too high, the total light transmittance tends to decrease due to end face reflection loss due to Fresnel reflection, and it is difficult to increase the refractive index with plastic lenses. Therefore, the refractive index of the lens is preferably in the range of 1.45 to 1.70, and within this range, it is preferable that the refractive index is as high as possible. Especially the refractive index is 1.55
If this becomes possible, it will be possible to compete thinly with commercially available inorganic glass prescription lenses. When designing a lens, in addition to satisfying the above-mentioned optical characteristics, it is necessary to consider the following performance. (1) Total light transmittance 85% or more (2) Impact resistance Passes FDA standards (3) Heat softening temperature Vicat heat softening temperature (load 1Kg)
100℃ or higher (4) Heat resistance yellowing ΔY<1 after heating at 100℃×5 hours (5) Weather resistance W-O-M ΔY<15 after 200 hours irradiation (6) Abrasion resistance Pencil hardness 2H< (7) Heat resistance Water-based 80℃×2hr No abnormality (8) Hot water resistance 40℃×10days No abnormality (9) Chemical resistance Immersed in acetone for 3 minutes No abnormality (10) Chemical resistance 0.1N−NaOHaq Immersed at room temperature for 2 hours
No abnormalities (11) Good dyeability (12) Good cutting/polishing properties The urethane resin of the present invention can be prepared by subjecting an isocyanate compound to a polyaddition reaction with a hydroxy compound. The specific details of each raw material are as follows. (1) Isocyanate compounds Examples of isocyanate compounds include hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,6-diisocyanate caproic acid methyl ester (lysine diisocyanate methyl ester), 2-isocyanate ethyl-2,
6-diisocyanate hexanoate, 1,
6,11-undecane triisocyanate is used, and each can be used alone or in combination. (2) Hydroxy compound Hydroxy compounds include 1,4-butanediol, 1,12-dodecanediol, 1,4
- A compound selected from cyclohexanedimethanol, 1,4-cyclohexanol, polyethylene glycol, polypropylene glycol, trimethylolpropane, 1,2,6-hexanetriol, and sorbitol. A general explanation of the method for producing the urethane resin plastic lens of the present invention is as follows. Manufacturing methods are broadly divided into cast polymerization and injection molding. The feature of the cast polymerization method is that it directly polymerizes and hardens the raw material monomer and simultaneously forms it into a lens shape. Therefore, the lenses are characterized by less molding distortion and excellent optical uniformity, and it is said that most commercially available prescription lenses made of plastic are made using this method. On the other hand, injection molding is a method in which pre-polymerized resin is injected into the shape of a lens, and methacrylic resin and polycarbonate resin for sunglasses and fashion glasses are manufactured using this method. In injection molding, it is necessary to ensure that the lens molded product has little optical molding distortion, and mold design and molding condition settings are important issues. Specifically speaking about the cast molding method, an isocyanate compound and a hydroxy compound are
After selecting a molar ratio of NCO to OH between 0.5 and 1.5 and mixing, a homogeneous solution is obtained either as is or by heating. Here, the isocyanate compound and the hydroxy compound may be used alone or in combination. Furthermore, the extent to which the reaction between isocyanate groups and hydroxyl groups is allowed to proceed is preferably controlled by the apparent melt viscosity of the resulting mixed solution (prepolymer). Depending on the selection of the isocyanate compound and the hydroxy compound, the resulting reaction mixture (prepolymer) may solidify.
In such cases, it is preferable to reduce the degree of reaction, raise the temperature, melt it, and handle it in liquid form.
Usually, the viscosity of the reaction mixture (prepolymer) is 1~
It is desirable to adjust to a range of 2000 poise. In order to adjust the reaction rate to a desired level, a known reaction catalyst used in the production of polyurethane may be added as appropriate. Furthermore, depending on the purpose, various substances other than hydroxy compounds, such as chain extenders, crosslinking agents, fillers, ultraviolet absorbers, and antioxidants, may be added as in known molding methods. The resulting viscous liquid mixture is defoamed by an appropriate method, then poured into an arbitrary mold without entrapping air bubbles, and reacted at an appropriate temperature. The reaction temperature is usually selected within the range of 0 to 200°C, preferably between room temperature and 150°C. The plastic lens of the present invention is made of urethane resin, and mainly consists of urethane bonds formed by isocyanate groups and hydroxyl groups.
Depending on the purpose, it is of course possible to contain allophanate bonds, urea bonds, biuret bonds, etc. in addition to urethane bonds. For example, increasing crosslink density by further reacting urethane bonds with isocyanate groups often provides desirable bonds. In this case, the reaction temperature is raised to at least 100° C. and a large amount of isocyanate component is used. Or again,
It is also possible to use a urea bond or a biuret bond by partially using an amine or the like. When using something other than a hydroxyl compound that reacts with an isocyanate compound as described above, particular attention must be paid to coloring. In addition, the composition for forming the resin of the present invention for the purpose of mechanical properties as a lens, processability (cutting property, polishing property, etc.), dyeability, and low viscosity for easy casting, etc. It is possible to add various compounds such as , vinyl monomer, polymerization initiator, plasticizer, and reaction diluent. The amount that these can be added is preferably 40% by weight or less based on the composition of the present invention. The lens made of the urethane resin of the present invention is
It has the following features compared to commercially available plastic lenses. (1) A strong plastic cleanser can be obtained. (2) It has excellent impact resistance, high refractive index, and high Abbe number. (3) The crosslinking density can be increased, thereby improving the properties necessary for lenses, such as high refractive index, abrasion resistance, and heat resistance. (4) Colorless and transparent resin can be obtained. (5) Low shrinkage rate during molding polymerization. (6) Less molding distortion of the lens. (7) Various compounds can be appropriately selected for each of the isocyanate compound and the hydroxy compound, thereby allowing the optical properties to be adjusted freely. The lens made of the urethane resin of the present invention is
In order to perform surface modification such as antireflection, imparting high hardness, improving abrasion resistance, chemical resistance, and imparting antifogging properties, known physical or chemical methods can be applied. The content of the present invention will be explained below with reference to Examples. Example 1 100g of hexamethylene diisocyanate as the isocyanate component and 54g of 1,4-butanediol as the hydroxyl component were subjected to a casting polyaddition reaction in a glass matrix according to the procedure described below to produce a plastic lens. was created. The reaction conditions for lens production and the performance of the produced lenses are shown in Tables 1 and 2. The lens appearance is colorless and transparent with good light transmission.
The refractive index n ²⁰ _D and Abbe number ν ²⁰ _D have optical properties of 1.50 and 55, respectively. It also has good impact resistance and is strong. Operation procedure (1) Place an isocyanate compound and a hydroxyl compound in a flask and heat at 90°C for several hours to prepare a prepolymer having a viscosity of about 5 poise at the same temperature. If it is difficult to liquefy at the same temperature, raise the temperature appropriately to liquefy. (2) Defoaming under reduced pressure to remove volatile components and air. (3) Adjust the viscosity by heating as necessary and inject into the glass matrix. The glass surface is treated to make it easier to peel off from the urethane resin layer, such as by making it hydrophobic in advance or applying a release agent. As the gasket, commonly used vinyl chloride or vinyl acetate polymer gaskets can be used, but silicone rubber gaskets are preferred. (4) Continue heating at a constant or programmed temperature while degassing under reduced pressure to polymerize into the shape of the lens. Example 2 100 g of 4,4'-dicyclohexylmethane diisocyanate and 34 g of 1,4-butanediol,
A cast polyaddition reaction was carried out according to Example 1 to produce a lens. Lens manufacturing conditions and characteristics are shown in Tables 1 and 2.
As shown in the table, a strong lens with excellent impact resistance was obtained. Example 3 A cast polyaddition reaction was performed using 100 g of hexamethylene diisocyanate and 53 g of trimethylolpropane (NCO/OH=1.0) according to Example 1 to produce a lens. Lens manufacturing conditions and characteristics are shown in Tables 1 and 2.
As shown in the table, a colorless, transparent and extremely strong lens was obtained. Example 4 A lens was prepared according to Example 1 using 100 g of 4,4'-dicyclohexylmethane diisocyanate, 44 g of bisphenol A (4,4'-isopropylidene diphenol), and 17 g of trimethylolpropane. Lens manufacturing conditions and characteristics are shown in Tables 1 and 2.
As shown in the table, an extremely strong and hard transparent lens was obtained. The refractive index n ²⁰ _D is 1.54, which is a fairly high value. It has excellent heat resistance, with no thermal deformation even at temperatures as high as 180℃. Example 5 A lens was prepared according to Example 1 using 100 g of 4,4'-dicyclohexylmethane diisocyanate, 28 g of 1,4-cyclohexanedimethanol, and 17 g of trimethylolpropane. Lens manufacturing conditions and characteristics are shown in Tables 1 and 2.
As shown in the table, a colorless, transparent and extremely hard lens was obtained. The optical properties are also good. It has excellent heat resistance and weather resistance (W-O-M irradiation test). Example 6 100 g of isophorone diisocyanate, 51 g of bisphenol A (4,4'-isopropylidene diphenol) and 20 g of trimethylolpropane,
A lens was produced according to Example 1. Lens manufacturing conditions and characteristics are shown in Tables 1 and 2.
As shown in the table, a colorless and transparent extremely hard lens was obtained. It has particularly excellent heat resistance and impact resistance. Example 7 A lens was prepared according to Example 1 using 100 g of tolylene diisocyanate, 41 g of 1,4-cyclohexanedimethanol, and 26 g of trimethylolpropane. Lens manufacturing conditions and characteristics are shown in Tables 1 and 2.
As shown in the table, the lens has a slightly yellow appearance, but is characterized by an extremely high refractive index n ²⁰ _D. It is very hard and has good impact resistance. Comparative Example 1 Diethylene glycol bisallyl carbonate polymer (CR-39) and methyl methacrylate polymer PMMA were selected as representative materials commercially available as plastic lenses, and a comparison with urethane resin materials is shown in Table 2. Ta. Urethane resin materials have the characteristic that optical properties such as refractive index can be freely changed by selecting the components, making it easy to obtain desired optical properties. It also has excellent heat resistance and impact resistance. Furthermore, the polymerization shrinkage rate of urethane resin is about 5% or less, about 15% of diethylene glycol bisallyl polymer, and about 20% of methyl methacrylate polymer.
significantly smaller than. This leads to excellent dimensional stability, which is a great merit.

【table】

【table】

[Table] Abbreviation HMDI Hexamethylene diisocyanate H ₁₂ MDI 4,4'-dicyclohexylmethane diisocyanate IPDI Isophorone diisocyanate TDI 2,4- and 2,6-(80/20) Tolylene diisocyanate 1,4-BD 1,4- Butanediol bisphenol A 4,4'-isopropylidene diphenol 1,4-CHMD 1,4-cyclohexanedimethanol TMP Trimethylolpropane

Claims (1)

[Claims] 1 Hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,6-diisocyanate caproic acid methyl ester (lysine diisocyanate methyl ester), 2-isocyanate ethyl-2,6-diisocyanate hexanoate,
At least one isocyanate compound selected from 1,6,11-undecane triisocyanate, 1,4-butanediol, 1,12-dodecanediol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanol, polyethylene glycol , polypropylene glycol, trimethylolpropane, 1,2,6-hexanetriol, and sorbitol, and is made of a urethane resin obtained by reacting with at least one hydroxy compound selected from
A plastic cleanser with excellent transparency that satisfies your needs.