JPH05269757A - Method for casting polymerization of plastic lens - Google Patents

Abstract

PURPOSE: To provide a lens excellent in workability, impact resistance, solvent resistance, etc., and having good transparency, hardness and high refractive index by carrying out an casting polymerization after mixing and compositing a specified monomer compound represented by a specified and generalized formula with other specified monomer represented by a specified and generalized formula. CONSTITUTION: A plastic lens is formed by casting polymerization after mixing and compositing at least one monomer compound selected from benzene ring containing polyisocyanate represented by formula I with at least one monomer compound selected from allyl group containing compounds represented by formula II. Here in formula I, X represents hydrogen, chlorine, bromine, methyl group or ethyl group, and Z represents hydrogen or methyl group. a and b satisfy 2<=b<=4, 1<=a<=4, and a+b<=6. In formula II, R1 represents phenol group and hydroxyl group or amino group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for casting and manufacturing a plastic lens, and more particularly to a method for casting and manufacturing a high refractive index polyurethane or polyurea lens.

[0002]

2. Description of the Related Art Compared to glass lenses, plastic lenses have a density of 1.01 to 1.40, which is 1/2 to 1/4 that of glass, are lightweight, and are superior in impact resistance, productivity, and dyeability. Due to its properties, it has been put to practical use in recent years as a lens for glasses, a camera, and a video.

Of these, resins obtained by casting polymerization using dipropyl carbonic acid (ethylene glycol) ester (hereinafter abbreviated as CR-39) are often used. However, the refractive index of this resin (N _D = 1.5) is lower than that of the glass lens, so the center thickness, peripheral thickness and curvature of each plastic lens should be increased to obtain the glass lens level engineering characteristics. Must be thickened.

Therefore, it is desired to find a resin having a higher refractive index and to develop a thinner lens with the resin at the same level of optical characteristics than a conventional plastic lens.

For resins having a high refractive index, PC
(N_D= 1.58 to 1.59) and PS (N _D= 1.59 to 1.60)
Although these are already known, these resins are thermoplastic
Yes, and the molding process is difficult, so for glasses
Not suitable for manufacturing lenses.

Therefore, it has a high refractive index and CR
It is further desired to discover a resin that can be cast polymerized similarly to -39 and develop a thin lens.

[0007] Conventionally, in order to meet the above demands, as a result of various studies, a method of casting polymerization of polyisocyanate and polyols or mercapto compounds has been proposed. However, this method has poor productivity because bubbles are likely to be generated in the polymerization and the molded product is difficult to remove from the mold. In order to solve this, there is a method of forming the release mold by treating the surface of the glass or metal lens mold with an external release agent in advance. However, since it is difficult to keep the thickness of the release mold constant, it is difficult to keep the surface accuracy of the lens constant, and a part or most of the released urethane resin lens is on the surface of the release mold. There is a problem that they are left behind and the lens surface condition and properties are significantly deteriorated. There is also a method by adding an internal mold release agent, but the internal mold release agent compound, when used in the polyisocyanate-mercapto compound reaction system, has low solubility with them, so the mixture becomes cloudy,
It has a drawback of deteriorating the optical characteristics of the molded product (see Japanese Patent Publication Nos. 1-185501, 1-26622, and U.S. Pat. No. 4,775,733).

[0008]

In view of the above, the present invention has discovered and developed a resin which not only has a high refractive index but also has good processability for cast polymerization. The objective is to provide a simple lens.

[0009]

[Means for Solving the Problems] To achieve the above object, the present inventor has extensively studied extensively, and
A benzene ring-containing isocyanate monomer is reacted with an allyl group-containing hydroxide and / or an allyl group-containing amine monomer to form a diallyl group-containing urethane or urea monomer compound, and this monomer compound Is a liquid state even at room temperature, and in order to reduce its viscosity, styrene, diallyl phthalate, halogenated styrene and the like diallyl group-containing urethane and urea monomer compound compatible copolymerizable monomer After adding the body as a diluent, it was discovered that a desired lens can be produced by injecting it into a glass or metal lens mold of a predetermined form in a uniform liquid state and performing cast polymerization. Was completed.

More specifically, the present invention provides the following formula
(I)

[Chemical 3] (In the above formula, X represents hydrogen, chlorine, bromine, a methyl group, or an ethyl group, Z represents hydrogen, or a methyl group, and a and b
Satisfying the relations of 2 ≦ b ≦ 4, 1 ≦ a ≦ 4, and a + b ≦ 6), and at least one monomer compound selected from the benzene ring-containing polyisocyanates represented by the following formula (II):

[Chemical 4] (In the above formula, R ₁ represents a phenol group, a hydroxyl group, or an amino group) is mixed with at least one monomer compound selected from allyl group-containing compounds, and then cast polymerization is performed. A method of manufacturing a plastic lens is provided.

In the above method, mixed synthesis is performed in a closed container. Whether or not the synthesis is completed can be confirmed by back titration with butylamine and disappearance of the isocyanato group. After mixed synthesis, a copolymerizable monomer compatible with at least one of the above-mentioned monomers selected from styrene, halogenated styrene and diallyl phthalate is used as a diluent at about 30 to about 50% by weight of the total amount. It is preferable to add it so that the mixed compound can maintain a liquid state even at room temperature. When using an allyl group-containing hydroxide as the formula (II), the amount of the diluent is about 30 to about total weight.
It is preferred to use 50% by weight, but if an allyl group containing amine is used, it is more preferred to use about 40 to about 50% by weight of the total weight.

In the above cast polymerization, it is preferable to use a free radical polymerization initiator. The type of free radical polymerization initiator is not particularly limited, but a peroxide compound such as diisopropylbenzene peroxide can be exemplified. The dose is preferably about 1 to 5% by weight of the total amount.

Before and after the above-mentioned mixed synthesis, an antioxidant, for example, an antioxidant having a discoloration-preventing cure such as thiodipropionate, and other stabilizers are used within a range that does not impair the light uniformity of the molded lens. It is preferable to add.

The polyisocyanate and the allyl group-containing compound are preferably in such a ratio that the molar ratio of NCO: OH and / or NH ₂ groups becomes about 0.5 to 3.0.

Regarding the reaction temperature, the temperature of the above-mentioned mixed synthesis is preferably 70 to 90 ° C, and the temperature of cast polymerization is preferably 90 to 150 ° C.

[0016]

The above and other objects, features and advantages of the present invention will be more apparent from the following synthetic examples and examples.

In the following Synthetic Examples and Examples, "parts" means "parts by weight" and "%" means "% by weight". Further, the refractive index of the molded lens shown in the examples, Abbe's number,
The cracking resistance, impact resistance, specific gravity, transmittance, saturated water absorption, surface hardness and shrinkage were measured by the following test methods.

Refractive index: 20 by Kalnew refractometer
N _D was measured at ° C. Abbe's number: N _D , N _F , N at 20 ° C by Carneu refractometer
After measuring _{C, it} was calculated by the following formula: Abbe number = (N _D −1) / (N _F −N _C ).

Cracking resistance: A lens sample was placed in a hot air oven at 120 ° C., and after 3 hours, no cracking or cracking was accepted, and it was judged to be acceptable, and marked (◯). Solvent resistance: After immersing the sample in an acetone, isopropanol, and benzene solution at room temperature for 2 days, those having no change on the surface were recognized as acceptable, and marked with (◯).

Specific gravity: Measured by the ASTM D-792 method. Surface hardness: Measured by the ASTM D-3363 method. Saturated water absorption rate: Measured by the ASTM D-570 method after immersion at room temperature for 24 hours.

Transmittance: 580n wavelength by ASTM D-1003 method
A 2 mm thick sample was measured in m 2. Impact resistance: 22mm diameter and 44g weight SU according to FDA regulations
Using an S ball, it was dropped perpendicularly to the lens surface from a height of 127 cm, and it was accepted as having no cracks or other damage on the lens, and was marked (○).

Synthesis Example 1 30 parts of diisocyanate-o-xylene was dissolved in 18.5 parts of allyl alcohol, and the mixture was heated and reacted for 3 hours to produce a diallyl-containing urethane compound. The product is referred to as Compound A.

Synthesis Example 2 30 parts of diisocyanate-o-xylene was dissolved in 42.7 parts of allylphenol, and the mixture was heated and reacted for 3 to 10 hours to form a diallyl-containing urethane compound. The product is referred to as Compound B.

Synthesis Example 3 30 parts of diisocyanate-o-xylene was dissolved in 18.2 parts of allylamine, and the mixture was heated and reacted for 2 to 4 hours to produce a diallyl-containing urea compound. The product is referred to as Compound C.

Example 1 At a temperature of 60 to 80 ° C., 100 parts of the compound A obtained in Synthesis Example 1 was dissolved by adding 3 parts of diisopropylbenzene peroxide, and the mixed solution was poured into a glass lens mold. , In order to carry out copolymerization at a temperature of 90 to 150 ° C,
It was left for 8 hours. The produced resin was taken out of the mold and tested for the refractive index, Abbe number, impact resistance, solvent resistance and the like. The results are shown in Tables 1 and 2.

[Table 1]

[Table 2] From Tables 1 and 2, the molded lens has a high refractive index,
Moreover, it can be seen that the impact resistance and solvent resistance are also excellent.

Example 2 To a mixture of 60 parts of the compound A obtained in Synthesis Example 1 and 40 parts of styrene, 3 parts of diisopropylbenzene peroxide was added and dissolved. Injecting the mixed solution into a glass lens mold,
In order to carry out the copolymerization, it was left at a temperature of 90 to 150 ° C. for 5 to 8 hours. Remove the generated resin from the mold,
Tests such as refractive index, Abbe number, impact resistance and solvent resistance were conducted. The results are shown in Tables 1 and 2. It can be seen from Tables 1 and 2 that the molded lens has a high refractive index and is excellent in impact resistance, solvent resistance and the like.

Examples 3 to 6 Using the components and ratios shown in Table 1, copolymerization was carried out in the same manner as in the methods of Examples 1 and 2 to produce lenses.
Tests such as refractive index, Abbe number, impact resistance and solvent resistance were conducted. The results are shown in Tables 1 and 2. It can be seen from Tables 1 and 2 that the molded lens has a high refractive index and is excellent in impact resistance, solvent resistance and the like.

Comparative Example 1 In a glass lens mold, 94 parts of m-xylylene isocyanate, 122 parts of pentaerythritol tetrakis (mercaptopropionate), and 0.05 parts of dibutyltin salt of dilauric acid (polymerization initiator) were used. Was injected, and the mixture was heated and polymerized at 60 ° C. for 3 hours and then cooled, but the resin lens was not released from the glass lens mold. Moreover, bubbles were generated during the heat polymerization, which was difficult to control.

Comparative Example 2 Although the same components as in Comparative Example 1 were cast and polymerized, the urethane resin lens was easily released from the mold because the inner wall of the glass mold was treated with an external release agent before casting. However, the surface of the lens was uneven and not flat. Further, it was the same as Comparative Example 1 in that bubbles were generated during the heat polymerization and were difficult to control.

[0030]

According to the method of the present invention, a lens having good transparency and hardness, a high refractive index, and excellent workability, impact resistance, solvent resistance and the like can be obtained. In addition, in the prior art, the isocyanato group reacts with water to easily release air bubbles and the molded product is difficult to extract from the mold, the present invention is to react the isocyanato group with a hydroxyl group or an amino group, for copolymerization. By eliminating the presence of an isocyanato group in the mixed compound, it is possible to solve the problem of air bubble release due to the reaction between the isocyanato group and water during copolymerization, and a molded article that occurs during the polymerization of the diallyl group-containing compound. The contraction can facilitate release.

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Claims (8)

[Claims] 1. The following formula (I): (In the above formula, X represents hydrogen, chlorine, bromine, a methyl group or an ethyl group, Z represents a hydrogen atom or a methyl group, and a and b
Satisfying the relations of 2 ≦ b ≦ 4, 1 ≦ a ≦ 4, and a + b ≦ 6), and at least one monomer compound selected from the benzene ring-containing polyisocyanates represented by the following formula (II): [Chemical 2] (In the above formula, R ₁ represents a phenol group, a hydroxyl group, or an amino group) is mixed with at least one monomer compound selected from allyl group-containing compounds, and then cast polymerization is performed. A method of manufacturing a plastic lens, comprising: 2. After the above-mentioned mixed synthesis, a copolymerizable monomer compatible with at least one kind of the above-mentioned mixed compound selected from styrene, halogenated styrene and diallyl phthalate is further used as a diluent in a total amount of 30 to 30. The method according to claim 1, characterized in that it is added at 50% by weight so that the mixed composition can maintain a liquid state even at room temperature. 3. The cast polymerization, wherein diisopropyl peroxide peroxide is used as a polymerization initiator.
The method according to claim 1 or 2. 4. The antioxidant and other stabilizers are added before and after the mixed synthesis within a range that does not impair the light uniformity of the molded lens. Method. 5. The ratio of the polyisocyanate and the allyl group-containing compound in such a ratio that the molar ratio of NCO group: OH and / or NH ₂ group is about 0.5 to 3.0. The method described in 1. 6. The method according to claim 1, wherein the temperature of the mixed synthesis is 70 to 90 ° C. 7. The method according to claim 1, wherein the temperature of the cast polymerization is 90 to 150 ° C. 8. The method according to claim 3, wherein the temperature of the cast polymerization is 90 to 150 ° C.