JPH0345362B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a synthetic resin lens that has a high refractive index for a synthetic resin (about 1.60), has excellent impact resistance, and is easy to process. Since the establishment of FDA standards in the United States in 1972, the safety of eyeglass lenses has been reviewed, and synthetic resins have come to be used in place of inorganic glass. The shift from inorganic glass lenses to synthetic resin lenses is a worldwide trend, and in Japan, the share of synthetic resin lenses is increasing year by year. In particular, the ratio of lenses made from diethylene glycol bisallyl carbonate (hereinafter abbreviated as CR-39) resin has already reached 50% in the United States and France.
expected to exceed. Synthetic resin lenses have improved safety (they have high impact resistance, and even if they break, they do not break into minute pieces like inorganic glass, so there is less chance of damaging your eyes). Lighter than glass and easier to process. It has many advantages such as being easy to color. On the other hand, CR39, which is used as the mainstream synthetic resin eyeglass lens material, has a low refractive index of 1.50 and weak mechanical strength, so even if the lens has the same power, it has a thicker center thickness than an inorganic glass lens. For this reason, the edge thickness of the lens (thickness around the lens) becomes significantly thicker, especially in negative lenses, and there is a strong latent demand from wearers for thinner lenses. Furthermore, polystyrene, polycarbonate, and the like, which are organic materials with a high refractive index, have problems in scratch resistance, beading property, polishability, heat resistance, and the like. Special publication55− for the purpose of improving the above-mentioned shortcomings.
13747, a copolymer of bisphenol A dimethacrylate or 2,2 bis(4-methacroyloxyethoxyphenyl)propane, etc. and styrene, or 0-chlorostyrene, phenyl methacrylate, benzyl methacrylate, etc. However, these polymers have poor weather resistance, are prone to yellowing, have poor scratch resistance, and do not satisfy the quality required for eyeglass lenses. Regarding impact resistance, recently there has been a rapid increase in the demand for inorganic coatings on lenses, and impact resistance after inorganic coating is important. Conventional resins for high refractive index lenses with good processability (Japanese Patent Publication No. 55-13747) cannot be coated with Meiki coating to produce lenses with a good balance of impact resistance, scratch resistance, and film heat resistance. do not have. Japanese Patent Publication No. 55-13747 states that it is good to copolymerize an acrylic acid alkyl ester in order to improve impact resistance, but this method not only leads to a decrease in the refractive index of the lens resin, but also Lens processability (especially polishability) deteriorates. In view of the above points, the present invention has been made in Japanese Patent Publication No. 55-13747.
This is a version of the above publication with improved impact resistance after inorganic material deposition. That is, the object of the present invention is to have excellent transparency required for eyeglass lenses, a relatively high refractive index in order to reduce the lens thickness, which is a latent requirement of eyeglass wearers, and a lens that is easy to process. The objective is to synthesize a synthetic resin lens with good impact resistance after being coated with an inorganic coating. The copolymer of the lens according to the present invention contains 10 to 30 equivalent % of a first monomer whose general formula is represented by [] and 1 to 15 equivalent % of a second monomer whose general formula is represented by [ ].
and 55 to 89 equivalent % of one or more radically polymerizable third monomers whose homopolymer has a refractive index of 1.55 or more.
It can be obtained by radical copolymerization of any monomer mixture. (R1 is hydrogen or methyl group, n+m is 0,
or an integer of 2, R2 is n1 is an integer from 6 to 20. ) In carrying out the present invention, the mixing ratio of the first monomer, second monomer, and third monomer is determined according to the ratios stated in the claims to achieve the characteristics required for the eyeglass lens. However, in order to have better properties, the first monomer, the second monomer, and the third monomer used, must be The amount of the monomer is preferably 15 to 25% by weight, the second monomer is preferably 3 to 10% by weight, and the third monomer is preferably 65 to 82% by weight. When the amount of the first monomer increases as shown in FIG. 1, the hardness of the lens substrate increases, and the scratch resistance when coated with an antireflection coating improves significantly. Heat resistance also improves. However, on the other hand, the impact resistance deteriorates as shown in FIG. 2, and the refractive index also decreases. When the amount of the second monomer increases, the flexibility of the lens increases, the impact resistance increases, and scratch resistance becomes less visible, making the scratch resistance appear better.
However, if a large amount of the second monomer is added, the refractive index decreases, making it impossible to obtain a lens with a high refractive index as originally intended. Further, the workability (especially in terms of polishability) is not significantly impaired. Therefore, by adding hardness to the lens with the first monomer and flexibility to the lens with the second monomer, we created a harmonious lens with excellent impact resistance after anti-reflection coating with a relatively high refractive index. You get what you get. When the composition ratio of the first monomer is less than 10 equivalent%, heat resistance, chemical resistance, impact resistance, chamferability,
Polishability decreases, and if it exceeds 30 equivalent %, impact resistance decreases, making it impossible to satisfy the properties required for lenses. If the composition ratio of the second monomer is less than 1 equivalent %, no improvement will be seen in impact resistance, and if it exceeds 15 equivalent %, heat resistance, scratch resistance, polishability, and refractive index will decrease, which is required for lenses. Don't be satisfied with the timing. The third monomer is preferably a transparent monomer that has a high refractive index and is not colored, such as chlorostyrene, styrene, allyl cinnamate, tribromophenyl acrylate, tribromophenyl ethylene oxyacrylate, acrylonitrile. Homopolymers such as , diallyl phthalate, and phenoxyethyl acrylate with a refractive index of 1.55 or more are preferable. In addition to the above-mentioned first, second, and third monomers, it is desirable to add about 0.05 to 1% of an ultraviolet absorber to improve light resistance. In the present invention, a polymerization initiator is placed in a space created by two glass molds with a predetermined curvature and a gasket, in addition to the first, second, and third elements and an ultraviolet absorber.
This is accomplished by adding 0.03 to 4 parts by weight and heating and polymerizing. Polymerization initiators related to the present invention include benzoyl peroxide, diisopropyl peroxycarbonate, lauroyl peroxide, t-butyl isobutyrate, and the like. The synthetic resin lens according to the present invention has excellent scratch resistance after coating, which could not be achieved with conventional high-refractive-index resins that have good workability (having beading and polishing properties).
It has excellent impact resistance. The scope of application of the present invention can be extended to not only eyeglass lenses but also camera lenses and other optical elements, and has great industrial significance. The present invention will be described in detail below based on Examples. Example 1 20 equivalent % of 2,2-bis(4-methacroyloxyethoxy)propane (hereinafter abbreviated as BM) was used as the first monomer, and polyethylene glycol dimethacrylate (molecular weight approximately 700) was used as the second monomer. Abbreviation
14EG) and 75 equivalents of styrene (hereinafter abbreviated as St) as the third monomer, 1% by weight of lauroyl peroxide and 2(2'-hydroxy-
0.3% by weight of 5'-methylphenyl)benzotriazole was added, and prepolymerization was carried out at 40°C for about 1 hour while stirring. Next, impurities in this prepolymerized product were removed with a filter, and the filtrate was injected into a space formed by a gasket made of soft polyvinyl chloride and two glass molds. Next, the material was heated at 40℃ for 10 hours, 40℃
A polymerized lens was obtained by heating the lens for 10 hours by increasing the temperature linearly from ℃ to 80℃. Then heat treated at 100℃ for 2 hours,
Removed distortion inside the lens. The refractive index, machinability, polishability, hardness, and impact resistance of the lenses thus manufactured were examined. The refractive index of the obtained lens is 1.560, Abbe number,
It was a colorless and transparent lens. In addition, the other characteristics sufficiently satisfied the characteristics required for lenses. Furthermore, 1 μm of silicon oxide was vapor-deposited on the obtained lens as an antireflection coating, and the scratch resistance, impact resistance, and heat resistance of the obtained lens were examined. The scratch resistance was comparable to that of the conventional CR-39 anti-reflection coated lens, and the impact resistance sufficiently met FDA standards with a lens having a center thickness of 2.0 mm. Lenses of various compositions were made by the same means as in Example 1. The results are shown in Table 1 as Examples and Comparative Examples. Figures 1 and 2 show 3mol of 14EG as the second component.
The impact resistance and abrasion resistance after inorganic coating of the BM/St/14EG system containing 14EG% and the BM/St system containing no 14EG are shown. From this figure, in the BM/St system that does not contain a second monomer, the scratch resistance of the lens after inorganic coating is BM
The higher the number, the better the impact resistance becomes. However, it was found that by adding 14EG, a well-balanced lens with sufficiently high scratch resistance after inorganic coating and good impact resistance could be obtained.
In terms of workability, the more BM the better. Here, BM is used as the first monomer, and BM is used as the second monomer.
14EG, but the other first monomers and second monomers also showed similar trends. As is clear from Table 1, the lens according to the present invention has a relatively high refractive index and satisfies the characteristics as a lens, and in particular, the lens characteristics after inorganic coating are good even when the second monomer is not included. This is an excellent product that is much improved compared to the one without it.

[Table] The test method for each characteristic was performed as follows. Refractive index: Measured at 20°C using an Atsube refractometer. Processability: Items that can be ground with a diamond edger for lens processing, or polished with a CR-39 lens polisher, and have a clean surface after grinding and polishing are considered good. Scratch resistance: A load of 1 kg was applied to S#000 steel wool and rubbed 20 times, and the degree of scratching was graded into 5 grades and evaluated. W: The same test as steel wool was conducted using a brass wire brush with 3 rows of 40 bundles of 0.3 mmφ x 2 cm. The outline is as follows. A: There is almost no damage. B: Slight damage. C: Scratches occur to the same extent as CR-39 resin. D; Damage between C and E. E: Damaged to the same extent as polymethyl methacrylate and polyethylene. Anti-reflection coated lens: 1 μm silicon oxide deposited. Coating condition: The anti-reflection coated lens should be left at 80℃ for 1 hour without peeling or cracking. Impact resistance: A ±0.000 lens with a center thickness of 1.6 mm was subjected to a steel ball drop test according to FDA standards, and those that did not break were considered good. The monomer abbreviations in Table 1 are as follows. Cl-St; Chlorstyrene St; Styrene BM; 2,2-bis(4-methacroyloxyethoxyphenyl)propane BP; Bisphenol A dimethacrylate 3002H; BMt; Benzyl methacrylate CR-39; Diethylene glycol bisallyl carbonate 14EG; Polyethylene glycol dimethacrylate (molecular weight approximately 740)

[Brief explanation of drawings]

Figure 1; Rockwell hardness and scratch resistance after inorganic coating (silicon oxide 1μ vapor deposition) according to composition of BM/St series and BM/St/14EG series; Figure 2; BM/St series and BM/St/14EG series Impact resistance after inorganic coating according to composition, wavy line; BM containing 3 equivalent% of 14EG/
St/14EG series, solid line; BM/St series.

Claims (1)

[Claims] 1. The first monomer 10 to 30 whose general formula is represented by []
Second monomer 1 whose equivalent % and general formula are represented by [ ]
~15 equivalent % and one or more radically polymerizable third monomers having a homopolymer refractive index of 1.55 or more55~
A synthetic resin lens characterized by being polymerized from 89 equivalent percent. (R1 is hydrogen or a methyl group, n+m is an integer of 0 or 2, R2 is n1 is an integer from 6 to 20. )