JPH0731281B2 - Plastic lens - Google Patents

Description

TECHNICAL FIELD The present invention relates to a plastic lens, and more specifically to a plastic lens made of a copolymer containing a sulfur atom.

[Conventional technology]

Recently, transparent plastic materials are light,
Since it has various features that cannot be obtained by the inorganic glass, such as high impact resistance and resistance to cracking, easy processing, and dyeability, it has begun to be used in various fields as a material for optical lenses.

In particular, as a material for eyeglass lenses for vision correction, light weight,
A plastic lens material is suitable because high impact resistance and easiness of dyeing are required as essential properties.

Furthermore, as a plastic lens material, a material having a high refractive index is required, because a plastic lens material having a high refractive index can reduce the edge thickness of the peripheral portion of the spectacle lens, for example. .

Conventionally, the most frequently used plastic lens material for spectacles is a diethylene glycol bisallyl carbonate resin, but this resin has a relatively low refractive index of about 1.50 and is not necessarily satisfactory in this respect.

On the other hand, as a plastic lens material having excellent impact resistance, a polyurethane resin has been studied in various fields, for example, JP-A-57-136601 and West German Patent No. 2,92.
No. 9,313, U.S. Pat. No. 3,907,864, U.S. Pat. No. 3,954,584 and others disclose lenses made of polyurethane resin.

However, these polyurethane resin lenses also do not have a sufficiently high refractive index and are not satisfactory in this respect.

Further, as a polyurethane resin having a higher refractive index, those containing a halogen atom have been proposed in JP-A-58-164615, JP-A-59-133211, JP-A-61-64716 and the like. ing. Thus, when containing a halogen atom, especially a bromine atom or an iodine atom,
The refractive index of the polymer increases depending on its content, but at the same time, the specific gravity of the polymer increases depending on the content of halogen atoms, and therefore the light weight, which is the most important feature of plastic materials The resulting plastic lens is one in which the advantages of high refractive index are greatly diminished. And, JP-A-61-64716
In the polyurethane resin of the publication, a monoepoxide adduct of polybrominated bisphenols is used as one component, but since it is a compound containing a large number of bromine atoms, it necessarily has a large specific gravity. In addition, since it contains an aromatic ring, the resulting polyurethane resin tends to yellow and does not have stable colorless transparency.

Further, JP-A-58-168614 proposes that a cross-linked structure is introduced into a polymer molecule by the reaction of a vinyl monomer having a hydroxyl group with an isocyanate compound.

[Problems to be solved by the invention]

As described above, a search has been made from each direction for a plastic lens having a high refractive index, excellent impact resistance, and a small specific gravity, but the current situation is that one that has not been sufficiently satisfied has not yet been obtained. .

The present invention has been made in view of the above circumstances, and an object thereof is to provide a plastic lens having a high refractive index, excellent impact resistance, and a small specific gravity.

[Means for solving problems]

The plastic lens of the present invention comprises the following component A and component B
Component and the following C component, the number of moles of the hydroxyl group of the A component is a, the number of moles of the isocyanate group of the B component is b and C
When the number of moles of the hydroxyl group of the component is c, the value of the ratio α = a / b is 0 <α ≦ 2.0, and the value of the ratio β = c / b is 0.01 ≦ β <
It is characterized by comprising a copolymer obtained by reacting at a relative ratio of 1.0 and polymerizing with the following D component in a ratio of 20 to 70% by weight based on the whole.

Component A: Monomer having radically polymerizable unsaturated group having hydroxyl group in molecule B component: Aliphatic polyisocyanate compound having plural isocyanate groups in molecule C component: represented by the following general formula (I) Sulfur compound having two hydroxyl groups in the molecule General formula (I) HOR ¹ -S-R ² OH (R ¹ and R ² each represent an aliphatic hydrocarbon group containing no halogen atom.) D component: the above Monomer Copolymerizable with Component A [Effect] The plastic lens according to the present invention has a high refractive index, excellent impact resistance, and a small specific gravity. The reason why such an effect is obtained is that a urethane bond is formed by the component B and the component A, and the component B and the component C respectively, so that the resulting copolymer is basically urethane excellent in impact resistance. This is because, in addition to having a resin structure, sulfur atoms are introduced by the C component, so that an excessively large specific gravity is avoided and a relatively high refractive index is obtained. That is, the copolymer formed by using the C component containing a sulfur atom has a higher refractive index as compared with a normal polyurethane polymer containing a compound having a hydroxyl group and an inesocyanate compound, and , Has a smaller specific gravity than that containing a halogen atom. Also,
When component B and the component do not contain an aromatic ring, a colorless and transparent stable copolymer can be obtained.

Hereinafter, the present invention will be specifically described.

In the present invention, a component A composed of a monomer having a radically polymerizable unsaturated group having a hydroxyl group in the molecule, and a component B having two or more isocyanate groups in the molecule,
A urethane bond is formed between the B component and the C component by reacting the C component composed of a sulfur compound having two hydroxyl groups in the molecule represented by the following general formula (I) with a specific relative ratio. And a residual hydroxyl group of the component B is reacted with a hydroxyl group of the component A to form a urethane bond, whereby the component A and the component C are bonded to the component B to form a radically polymerizable urethane monomer. And a copolymer having a urethane bond thus obtained is used as a material. Get a plastic lens.

In formula (I) HOR ¹ —S—R ² OH, each of R ¹ and R ² represents an aliphatic hydrocarbon group containing no halogen atom, and preferably has 2 to 15 carbon atoms.

In the above, when the number of moles of the isocyanate group of the B component is b and the number of moles of the hydroxyl group of the C component is c, the ratio β of the ratio c / b needs to be smaller than 1. By satisfying this condition, even when all of the hydroxyl groups of the C component react with the isocyanate groups of the B component, unreacted isocyanate groups are present at the terminals of the molecule of the urethane compound. The component A can react with and bind to the compound A, thereby forming a crosslinkable polyfunctional urethane monomer. Then, by polymerizing this urethane monomer together with the component D, a copolymer for the intended plastic lens can be obtained.

In the present invention, specific examples of the aliphatic polyisocyanate compound having a plurality of isocyanate groups used as the component B include, for example, hexamethylene diisocyanate, octamethylene diisocyanate, isophorone diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate and dicyclohexyl. Methane diisocyanate, tetramethylene diisocyanate, biuretization reaction product of hexamethylene diisocyanate, compound of trimer structure or adduct reaction product with trimethylolpropane, trifunctional or tetrafunctional polyisocyanate compound derived from isophorone diisocyanate, 2-isocyanate Although ethyl-2,6-diisocyanate ethyl hexanoate and the like can be mentioned,
It is not limited to these. Further, this polyisocyanate compound can be used not only in one kind but also in two or more kinds.

By using such an aliphatic polyisocyanate compound, a colorless and transparent stable copolymer required as a material for a plastic lens can be obtained. On the other hand, when an aromatic polyisocyanate compound containing an aromatic ring is used as the polyisocyanate compound, the resulting copolymer tends to yellow due to heat or light.

In the present invention, specific examples of the sulfur compound used as the component C include 2,2'-thiodiethanol. By using a sulfur compound that does not contain an aromatic ring in the molecular structure as the C component, a colorless and transparent stable copolymer can be reliably obtained, as in the case of the polyisocyanate compound.

In the present invention, as a specific example of the radically polymerizable unsaturated group-containing monomer having a hydroxyl group used as the component A, an acrylic acid ester having a hydroxyl group represented by the following general formula (II) or Methacrylic acid ester can be mentioned.

General formula (II) (In the formula, n is an integer of 1 to ³ , R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an aliphatic or aromatic hydrocarbon group having 2 to 12 carbon atoms.) General formula (II ), Specific examples of the compound represented by
Hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-hydroxy-3-phenoxypropyl methacrylate, 4
-Hydroxybutyl methacrylate and the like can be mentioned, but the present invention is not limited thereto.

Furthermore, examples of the monomer used as the component A include a monomer containing a hydroxyl group and two or more radical polymer unsaturated groups. Specific examples thereof include 2-hydroxy-1-acryloxy-3-methacryloxypropane and tetramethylolmethane triacrylate.

In addition to the above, various polyols such as allyl alcohol, methacrylic alcohol, polyester polyols having unsaturated groups, and polyether polyols can also be mentioned as examples of the component A.

In a typical method for producing the plastic lens of the present invention, first, the above-mentioned A component, B component and C
The components are mixed and reacted to form a urethane monomer containing a sulfur atom and having a radically polymerizable unsaturated group. This urethanization reaction is usually from room temperature to 200
It can be carried out at temperatures in the range up to ° C. In this urethanization reaction, in order to shorten the reaction time, it is possible to appropriately use a reaction catalyst used in the production of ordinary polyurethane, for example, dibutyltin dilaurate, stanas octoate, dimethyltin dichloride, stannic chloride. it can. Further, this urethanization reaction may be carried out in an organic solvent inert to the urethane bond forming reaction,
The urethane monomer is obtained by removing the organic solvent after the reaction is completed.

In the above urethanization reaction, as described above, the ratio c /
The value β of b is less than 1 and 0.01 or more, preferably 0.02
It is necessary to be above. When the value of β is smaller than 0.01, the amount of C component used is extremely small,
In the obtained copolymer, the high refractive index due to the sulfur atom is insufficiently expressed. Further, the relative proportions of the A component, the B component and the C component are such that the value α of the ratio a / b is 0 <α ≦ 2.0, preferably 0.2 ≦ α ≦, where a is the number of moles of the hydroxyl group of the A component.
The range is 1.5. If the value of α is too large, the resulting copolymer may be discolored, while if it is too small, the resulting copolymer may be inferior in durability.

Next, this urethane monomer is copolymerized with the component D,
This forms the copolymer for the plastic lens of the present invention.

One of the reasons why the D component is used is as follows.
This is because the urethane monomer that is a reaction product of the B component and the C component may become a viscous liquid or solid. That is, even in such a case, since the monomer composition to be polymerized can be made into a liquid having a low viscosity by using the component D, the polymerization treatment can be easily performed. Further, by selecting the type of the D component, it becomes possible to obtain the properties suitable for the intended use of the obtained copolymer. From the above viewpoints, the monomer used as the component D is preferably a liquid substance having a low viscosity.

The urethanization reaction described above can be carried out in the presence of the component D.

Specific examples of the component D include aromatic vinyl compounds such as styrene, α-methylstyrene, chloromethylstyrene and divinylbenzene, allyl compounds such as diallyl phthalate, diallyl isophthalate and diethylene glycol bisallyl carbonate, methyl methacrylate, and the like. Various acrylates and methacrylates such as 2-ethylhexyl methacrylate, n-butyl acrylate, diethylene glycol dimethacrylate, 1,3-butanediol diacrylate, phenyl methacrylate and 2,2-bis (4-methacryloxyethoxyphenyl) propane However, the present invention is not limited to these. The D component may be used alone or in combination of two or more.

The proportions of the above-mentioned urethane monomers of the A component, the B component and the C component and the D component can be changed depending on the intended use of the plastic lens. The body is in the range of 30 to 80% by weight, and the D component is in the range of 20 to 70% by weight. If the proportion of the urethane monomer is less than 30% by weight, the proportion of urethane bonds will be small, and a copolymer having excellent impact resistance cannot be obtained. Further, when the ratio of the urethane monomer to the whole is more than 80% by weight, the viscosity of the monomer composition may become excessively high, and at this time, the monomer composition has sufficient fluidity. Since it is not possible to directly inject this into the mold for casting polymerization, it is not possible to use the preferred casting polymerization method as a method for producing a plastic lens.

The above-mentioned copolymer of the urethane monomer and the component D has a crosslinked structure because the corresponding part of the urethane monomer has a plurality of components A bonded to the ends thereof.

When the plastic lens of the present invention is produced, it is almost impossible to carry out melt molding because the copolymer has a crosslinked structure as described above. Therefore, the cast polymerization method is preferably used.

In the case of obtaining the plastic lens of the present invention by the cast polymerization method, plate-shaped, lens-shaped, cylindrical, prismatic, conical, spherical, designed according to other applications, glass,
Prepare a mold or mold made of plastic, metal, etc., and add a prescribed proportion of A component,
A monomer composition obtained by mixing a urethane monomer, which is a reaction product of the component B and the component C, and the component D together with a radical polymerization initiator may be injected, and the temperature may be raised to perform polymerization. .

At the time of polymerization, various additives can be added to the monomer composition as needed. As an additive here,
Colorants, ultraviolet absorbers, antioxidants, heat stabilizers, and the like are used depending on the intended use of the obtained lens.

The obtained molded product may be used as it is as a target lens, or the molded product may be further ground and polished to be a desired plastic lens.

In the above, in order to obtain the plastic lens of the present invention, the case where the formation reaction of the urethane monomer by the components A, B and C is carried out prior to the copolymerization reaction with the component D has been described. It is not always essential to carry out the reaction in advance. That is, first, the component A and the component D may be copolymerized to form a polymer, and the hydroxyl group of the component A in this polymer and the component B may be reacted with the component C to form a urethane bond. It is also possible to carry out the polymerization of the A component and the D component to some extent, then to carry out the urethane bond forming reaction, and then to complete the polymerization. In these cases, the ratio of the A component, the B component, the C component and the D component in the finally obtained polymer needs to be in the same range as described above. By carrying out the copolymerization reaction in advance, the subsequent urethanization reaction may not proceed smoothly. In such a case, it is preferable to carry out the urethanization reaction in advance.

With respect to the plastic lens of the present invention obtained as described above, dyeing, surface polishing, and antistatic treatment are performed, if necessary, to further improve various characteristics as a lens, and surface hardness. In order to raise the height, it is of course possible to carry out secondary processing such as an inorganic or organic hard coat or a non-reflective coat which is applied to a normal lens.

Examples of the present invention will be described below, but the present invention is not limited thereto.

Example 1 2-Hydroxyethyl methacrylate 17.3 g, isophorone diisocyanate 29.6 g, 2,2'-thiodiethanol 8.1 g, styrene 30 g, and α-methylstyrene 15 g were thoroughly mixed, and dibutyltin dilaurate was added thereto. 0.01 g
Was added and reacted at 60 ° C. for 2 hours to carry out a urethanization reaction. Here, α = 0.502 and β = 0.498.

To the liquid obtained here, 1 g of lauroyl peroxide was further added to obtain a monomer composition, which was poured into a glass mold having a spherical inner surface, and then at 50 ° C. for 2 hours, 60 Copolymerization reaction is performed under different conditions such as 10 ° C for 10 hours, 80 ° C for 2 hours, and 100 ° C for 3 hours, center thickness 2mm, diameter 75mm
A concave lens made of the transparent copolymer of was obtained.

When the refractive index of this copolymer was measured with an Abbe refractometer, it was found that n ²⁰ _D = 1.581.

Also, this lens is completely insoluble in ordinary organic solvents such as methanol, ethanol, acetone, toluene,
It was recognized that it had a sufficient crosslinked structure.

Furthermore, in accordance with the US FDA standards, a steel ball weighing 16.33 g has a height of 127
When an impact resistance test was conducted on this lens by dropping a steel ball from a height of cm to the sample, it was found that the lens had no damage and had excellent impact resistance.

The specific gravity of this copolymer was 1.13, which was extremely small.

Comparative Example 1 2-Hydroxyethyl methacrylate 17.6 g, isophorone diisocyanate 30.2 g, and diethylene glycol
7.2 g, 30 g of styrene, and 15 g of α-methylstyrene were thoroughly mixed, and a urethanization reaction and polymerization were carried out by the method according to Example 1 to form a transparent copolymer having a center thickness of 2 mm and a diameter of 75 mm. I got a concave lens. Where α = 0.50
0 and β = 0.500.

The refractive index of this copolymer is ▲ n ²⁰ _D ▼ = 1.534, and the specific gravity is 1.13.
Met.

On the other hand, when an impact resistance test was conducted on this lens by the same method as in Example 1, no damage was found.

From the above, the copolymer obtained in Example 1 contains a sulfur atom, so that both have a low specific gravity and excellent impact resistance as compared with the copolymer of Comparative Example 1. However, in addition, it is clear that it has a high refractive index.

Example 2 2-Hydroxy-3-phenoxypropyl acrylate
35.8g, hexamethylene diisocyanate 13.9g, 2,
0.3 g of 2'-thiodiethanol, 10 g of diethylene glycol dimethacrylate, and 40 g of α-methylstyrene were thoroughly mixed, and urethanization reaction and polymerization were carried out by the method according to Example 1 to obtain a center thickness of 1.7 mm and a diameter of 80 mm. A concave lens made of the transparent copolymer of was obtained. Where α = 0.
980, β = 0.030.

The refractive index of this copolymer is ▲ n ²⁰ _D ▼ = 1.576, and the specific gravity is 1.16.
Met.

Moreover, when an impact resistance test was conducted on this lens in the same manner as in Example 1, it was found that no crushing occurred and that it had excellent impact resistance.

Claims (1)

[Claims] 1. The following A component, the following B component and the following C component, the number of moles of hydroxyl groups of the A component is a, the number of moles of isocyanate groups of the B component is b, and the number of moles of hydroxyl groups of the C component is c. , The ratio α = a / b is 0 <α ≦ 2.0, and the ratio β = c / b is 0.01 ≦ β <1. A plastic lens comprising a copolymer obtained by polymerizing with the following component D in a proportion of 20 to 70% by weight. Component A: Monomer having radically polymerizable unsaturated group having hydroxyl group in molecule B component: Aliphatic polyisocyanate compound having plural isocyanate groups in molecule C component: represented by the following general formula (I) Sulfur compound having two hydroxyl groups in the molecule General formula (I) HOR ¹ -S-R ² OH (R ¹ and R ² each represent an aliphatic hydrocarbon group containing no halogen atom.) D component: the above Monomer copolymerizable with component A