JPH054642B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to plastic lens materials, and more particularly to plastic lens materials containing sulfur atoms.

[Conventional technology]

In recent years, transparent plastic materials have various features that cannot be obtained with inorganic glass, such as being light, having high impact resistance and being difficult to break, being easy to process, and being able to be dyed. It is beginning to be used in a variety of fields as a material for lenses.

In particular, as a material for eyeglass lenses for vision correction,
Plastic lens materials are preferred because essential properties include light weight, high impact resistance, and ease of dyeing.

Furthermore, plastic lens materials are required to have a high refractive index because, for example, plastic lens materials with a high refractive index can reduce the edge thickness of the periphery of eyeglass lenses. .

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

On the other hand, polyurethane resins have been studied in various fields as plastic lens materials with excellent impact resistance.
No. 3907864, U.S. Patent No. 3954584,
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, polyurethane resins containing halogen atoms having a higher refractive index have been proposed in JP-A-58-164615 and JP-A-59-133211. In this way, when containing halogen atoms, especially bromine atoms and iodine atoms, the refractive index of the polymer increases according to the content, but at the same time, the refractive index of the polymer increases according to the content of halogen atoms. The specific gravity of the coalescence increases, and as a result, the light weight, which is the greatest feature of plastic materials, is lost, and the resulting plastic lens material has the advantage of having a high refractive index greatly diminished.

Furthermore, a method in which a crosslinked structure is introduced into a polymer molecule by reacting a vinyl monomer containing a hydroxyl group with an isocyanate compound has been proposed, such as in Japanese Patent Application Laid-open No. 168614/1983.

[Problem that the invention seeks to solve]

As described above, various efforts have been made to find a plastic lens material with a high refractive index and excellent impact resistance, but the present situation is that nothing that is fully satisfactory has yet been obtained.

The present invention was made based on the above circumstances, and an object of the present invention is to provide a plastic lens material that has a high refractive index, excellent impact resistance, and a low specific gravity.

[Means for solving problems]

The plastic lens material of the present invention includes the following component A, the following components B and C, the total number of moles of thiol groups and hydroxyl groups in component A being a, the number of moles of isocyanate groups in component B being b, and C. When the total number of moles of the thiol group and hydroxyl group of the components is c, the reaction is performed at a relative ratio such that the value of the ratio b/c is greater than 1 and the value of the ratio (a+c)/b is 0.5 to 2.0. It is characterized in that it consists of a copolymer obtained by polymerizing it together with component D below in a proportion of 20 to 50% by weight based on the total.

A component: Acrylic ester or methacrylic ester monomer having a thiol group or hydroxyl group in the molecule B component: A polyisocyanate compound having multiple isocyanate groups in the molecule C component: Aliphatic mercapto alcohol or aliphatic dithiol compound D Component: Aromatic vinyl compound copolymerizable with component A [Effects] The plastic lens material according to the present invention has a high refractive index, excellent impact resistance, and has a small specific gravity. The reason why such an effect is obtained is that in this polymer, thiourethane bonds (thiocarbamate ester bonds) are formed by component B and component C. is formed, and when component A has a thiol group, a thiourethane bond is also formed by component A and component B, and when component A or component C has a hydroxyl group, the urethane bond is formed by the hydroxyl group. As a result of the bond formation, the resulting copolymer basically has the structure of a urethane resin with excellent impact resistance, and contains many sulfur atoms in the molecule to form thiourethane bonds. This is because the specific gravity can be avoided from becoming excessive and the refractive index can be increased. That is, by forming thiourethane bonds with sulfur atoms, the resulting polymer has a higher refractive index than a polymer having only normal polyurethane bonds with a compound having a hydroxyl group and an isocyanate compound. Moreover, it has a lower specific gravity than those containing halogen atoms.

The present invention will be specifically explained below.

In the present invention, component A consisting of an acrylic ester or methacrylic ester monomer having a thiol group or hydroxyl group in the molecule, component B having two or more isocyanate groups in the molecule, and an aliphatic mercapto alcohol or By reacting component C consisting of an aliphatic dithiol compound at a specific relative ratio, component B and component C form a thiourethane bond or a urethane bond, and the remaining isocyanate groups in component B are reacted. , by reacting with the thiol group or hydroxyl group of component A to form a thiourethane bond or urethane bond.
The components are combined, thereby producing a thiourethane monomer having radical polymerizability, which is further copolymerized with component D, which is copolymerizable with component A, by utilizing the radical polymerizability of component A. The obtained copolymer having thiourethane bonds is used as a lens material.

In the above, when the number of moles of isocyanate groups in component B is b, and the total number of moles of thiol groups and hydroxyl groups in component C is c, the value α of the ratio b/c is greater than 1 and less than 100, It is preferably 50 or less. Because α is larger than 1, even when all of the thiol groups or hydroxyl groups of component C react with the isocyanate groups of component B,
An unreacted isocyanate group exists at the end of the molecule of the thiourethane compound, and component A can react and bond to this isocyanate group, thereby forming a crosslinkable polyfunctional thiourethane monomer. A mass is formed. When α is greater than 100, the C component is too small relative to the B component, so the copolymer has a low refractive index and poor impact resistance. Then, by polymerizing this thiourethane monomer together with component D, a plastic lens material made of the desired copolymer can be obtained.

In the present invention, specific examples of polyisocyanate compounds having a plurality of isocyanate groups used as component B include hexamethylene diisocyanate, octamethylene diisocyanate, isophorone diisocyanate, 2,2,4
- trimethylhexamethylene diisocyanate,
Dicyclohexylmethane diisocyanate, tetramethylene diisocyanate, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, naphthalene diisocyanate, 3,3'-
Biuret-forming reaction products of dimethyl-4,4'-bisphenylene diisocyanate, metaxylylene diisocyanate, hexamethylene diisocyanate, compounds with trimer structure or adduct reaction products with trimethylolpropane, trifunctional derivatives derived from isophorone diisocyanate to tetrafunctional polyisocyanate compounds, 2-isocyanate ethyl-2,6-diisocyanate ethylhexanoate, etc.
It is not limited only to these.

Among the above, aliphatic isocyanate compounds or hexyl isocyanate compounds that produce polymers that are less likely to yellow than aromatic isocyanate compounds that tend to cause yellowing of the resulting polymers due to heat or light. It is preferable to use polyfunctional derivatives of methylene diisocyanate, etc., and thereby a colorless, transparent and stable polymer required as a plastic lens material can be obtained.

In the present invention, specific examples of the aliphatic mercapto alcohol or aliphatic dithiol compound used as component C include 2-mercaptoethanol, ethanedithiol, 1,2-propanedithiol, 1,3-propanedithiol,
-mercaptoethyl ether, 2-mercaptoethyl sulfide, di(2-mercaptoethyl) ether, and the like.

In the present invention, the acrylic ester or methacrylic ester monomer having a hydroxyl group or thiol group used as component A includes, for example, aliphatic or aromatic mercapto alcohols or dithiols, and acrylic acid or methacrylic acid. Examples include esters according to

In addition to these, acrylic esters or tacrylic esters containing a hydroxyl group represented by the following general formula () can be mentioned.

General formula () (In the formula, n is an integer of 1 to 3, R ¹ is a hydrogen atom or a methyl group, and R ² represents an aliphatic or aromatic hydrocarbon residue having 2 to 12 carbon atoms that may contain various substituents.) Specific examples of the compound represented by the general formula () include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-phenoxy-2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, Phenoxy-2-
Examples include hydroxypropyl methacrylate and 4-hydroxybutyl methacrylate, but are not limited to these.

Furthermore, monomers containing a hydroxyl group and two or more acrylic or methacrylic groups can be mentioned. As a specific example, for example,
Examples include 2-hydroxy-1-acryloxy-3-methacryloxypropane and tetramethylolmethane triacrylate.

In a typical method for producing the plastic lens material of the present invention, first, the above components A, B and C are mixed and reacted,
A thiourethane monomer having a radically polymerizable unsaturated group is formed which contains a thiourethane bond and may also have a urethane bond. This thiourethane formation reaction can usually be carried out at a temperature ranging from room temperature to 200°C. In this thiourethane-forming reaction, in order to shorten the reaction time, reaction catalysts used in the production of ordinary polyurethanes, such as dibutyltin dilaurate, stannath octoate, dimethyltin dichloride, and stannic chloride, may be used as appropriate. I can do it. Further, this thiourethane formation reaction may be carried out in an organic solvent inert to the thiourethane bond formation reaction, and a thiourethane monomer can be obtained by removing the organic solvent after the reaction is completed.

In the above thiourethane reaction, as mentioned above, the value α of the ratio b/c is greater than 1 and less than 100,
It is preferably 50 or less. The relative proportions of component A, component B, and component C are such that, when the total number of moles of thiol groups and hydroxyl groups in component A is a, the value β of the ratio (a+c)/b is 0.5.
-2.0, preferably 0.7-1.5. If the value of this ratio β is too large, the obtained polymer may be discolored, and if it is too small, the obtained polymer may have poor durability.

Next, this thiourethane monomer is copolymerized with component D, thereby forming a copolymer which is the plastic lens material of the present invention.

The reason why component D is used in this manner is that thiourethane monomer, which is a reaction product of component A, component B, and component C, may become a viscous liquid or solid. That is, even in such a case, by using the D component,
Since the monomer composition to be polymerized can be made into a liquid with low viscosity, the polymerization treatment with component D can be easily performed. It is also preferable in that by selecting the type of component D, it is possible to obtain properties suitable for the intended use in the resulting copolymer. From this point of view, the monomer used as component D is preferably a liquid substance with low viscosity.

In addition, the thiourethane reaction described above can be carried out in the presence of component D. It is also a simple method to use component D in a system in which no organic solvent is present.

Specific examples of component D include styrene, α
- Aromatic vinyl compounds such as methylstyrene, chloromethylstyrene and divinylbenzene may be mentioned.

The ratio of the thiourethane monomers made up of components A, B, and C to component D can be changed depending on the intended use of the plastic lens material. Urethane monomer is 50 to 80% by weight of the whole
The D content is in the range of 20 to 50% by weight. If the proportion of the thiourethane monomer is less than 50% by weight, the proportion of thiourethane bonds and urethane bonds will be small, making it impossible to obtain a copolymer with excellent impact resistance. In addition, if the proportion of thiourethane monomer to the whole is excessive, the viscosity of the monomer composition may become excessively high, and in this case, the monomer composition does not have sufficient fluidity. , it becomes impossible to directly inject this into a mold for cast polymerization, and the cast polymerization method, which is preferred as a method for producing plastic lenses, cannot be used.

The copolymer of the thiourethane monomer and component D has a crosslinked structure because a considerable portion of the thiourethane monomer has a plurality of components A bonded to its terminals.

When producing a lens using the plastic lens material of the present invention, it is almost impossible to perform melt molding because the copolymer has a crosslinked structure as described above. Therefore, cast polymerization is preferably used.

When the plastic lens material of the present invention is obtained by the cast polymerization method, the plastic lens material of the present invention may be formed into plate-like, lens-like,
A mold or formwork (mold) made of glass, plastic, metal, etc. is prepared in a cylindrical, prismatic, conical, spherical, or other shape depending on the purpose, and a predetermined proportion of component A is added to the mold. , a monomer composition obtained by mixing a thiourethane monomer, which is a reaction product of components B and C, and component D with a radical polymerization initiator is injected, and the mixture is heated and polymerized. Bye.

During polymerization, various additives can be added to the monomer composition as necessary. As additives, colorants, ultraviolet absorbers, antioxidants, heat stabilizers, and others are used depending on the intended use of the resulting lens.

The obtained molded product may be used as the desired lens material as it is, or it can be further cut and polished to obtain the desired lens material.

Above, in order to obtain the plastic lens material of the present invention, a case has been described in which the thiourethane monomer formation reaction with component A, component B, and component C is performed prior to the polymerization reaction with component D. It is not always essential to carry out the urethanization reaction first. That is, first, component A and component D are polymerized to some extent to form a prepolymer, and the thiol group or hydroxyl group of component A in this prepolymer is reacted with component B together with component C to form a thiourethane bond or a urethane bond. It is also possible to form both bonds and then complete the polymerization. In these cases as well, in the finally obtained polymer, the A component, B component, C component and the proportions of the components need to be within the same range as above. Note that by performing the polymerization reaction in advance, there is a possibility that the subsequent thiourethane reaction may not proceed smoothly. In such a case, it is preferable to carry out the thiourethane formation reaction first.

The plastic lens material of the present invention obtained as described above may be dyed or
By performing surface polishing and antistatic treatment, we can further improve the various properties of the lens, and in order to increase the surface hardness, we apply secondary coatings applied to ordinary lenses, such as inorganic or organic hard coats or non-reflective coats. Of course, it is also possible to perform processing.

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

Example 1 2-hydroxyethyl methacrylate 24.0g
, 34.7g of metaxylylene diisocyanate,
Thoroughly mix 11.3 g of ethanedithiol and 30 g of styrene, and add dibutyltin dilaurate to this.
0.01 g was added and reacted at 60°C for 2 hours to perform a thiourethane reaction. Here, a=0.18 mole,
b=0.37 mol, c=0.24 mol, α=1.54, β=
1.15, and the proportion of styrene as component D is 30% by weight based on the total monomer. Note that α is the value of the ratio b/c, and β is the value of the ratio (a+b)/b.

To the obtained liquid, 1 g of lauroyl peroxide was further added to obtain a monomer composition, which was poured into a glass mold with a spherical inner surface and heated at 50°C for 2 hours for 60 hours. A polymerization reaction was carried out at 10°C for 10 hours, 80°C for 2 hours, and 100°C for 3 hours to obtain a concave lens made of a transparent polymer with a center thickness of 2.1 mm and a diameter of 75 mm.

When the refractive index of this lens was measured using an Atsube refractometer, it was n ²⁰ _D =1.577.

This lens also supports methanol, ethanol,
It was completely insoluble in common organic solvents such as acetone and toluene, and was recognized to have a sufficient crosslinked structure.

Furthermore, in accordance with US FDA standards, this lens was subjected to an impact resistance test using the steel ball drop method, in which a steel ball weighing 16.33 g was dropped onto a sample from a height of 127 cm, and there was no damage at all, indicating that it was excellent. It was recognized that the material had good impact resistance.

Further, the specific gravity of this polymer was extremely low at 1.22.

Comparative example 1 2-hydroxyethyl methacrylate 26.1g
, 37.7g of metaxylylene diisocyanate,
6.2 g of ethylene glycol and 30 g of styrene were thoroughly mixed, and urethanization reaction and polymerization were carried out in the same manner as in Example 1. Here, a=
0.20 mol, b=0.40 mol, c=0.20 mol, α=
2.00, β=1.00, and the proportion of styrene as component D is 30% by weight based on the total monomer.

The obtained polymer had a refractive index n ²⁰ _D =1.560 and a specific gravity of 1.21.

From the above, it is clear that the polymer obtained in Example 1 has the same specific gravity as that of Comparative Example 1, but has a higher refractive index.

Comparative example 2 2-hydroxyethyl methacrylate 20.27g
, 29.32g of xylylene diisocyanate, and 2.
20.41 g of 2-bis(bromomethyl)-1,3-propanediol and 30 g of styrene were thoroughly mixed, and a urethanization reaction and a polymerization reaction were performed by a method similar to Example 1 to obtain a copolymer. Ta. Here, a=0.156 mol, b=0.312 mol, c=0.156
mole, α = 2.00, β = 1.00, and the proportion of styrene as component D is 30% by weight based on the total monomer.
It is.

The obtained copolymer had a refractive index n ²⁰ _D =1.573 and a specific gravity of 1.42.

From the above, it is clear that the polymer obtained in Example 1 has a refractive index equal to or higher than that of Comparative Example 2, and has a lower specific gravity.

Example 2 2-hydroxyethyl methacrylate 18.9g
, 32.2 g of isophorone diisocyanate, 8.9 g of ethanedithiol, and 40 g of styrene were thoroughly mixed, and a thiourethane reaction and polymerization were carried out in the same manner as in Example 1 to form a transparent material with a center thickness of 2 mm and a diameter of 75 mm. A concave lens made of a copolymer was obtained. Here, a = 0.145 mol, b = 0.29 mol, c
= 0.189 mol, α = 1.53, β = 1.15, and the proportion of styrene as the D component is 40% of the total monomer.
Weight%.

The refractive index of this lens is n ²⁰ _D = 1.550, and the specific gravity is 1.12.
It was hot. In addition, when an impact resistance test was conducted on this concave lens in the same manner as in Example 1, it was found that
No crushing occurred, and it was found that it had excellent impact resistance.

Comparative example 3 2-hydroxyethyl methacrylate 20.4g
, 34.8 g of isophorone diisocyanate, 4.8 g of ethylene glycol, and 40 g of styrene were thoroughly mixed, and urethanization reaction and polymerization were performed in a manner similar to Example 1 to obtain a copolymer. Here, a=0.157 mol, b=0.313 mol, c=0.155
moles, α = 2.02, β = 0.99, and the proportion of styrene as component D is 40% by weight based on the entire monomer.
It is.

The refractive index of this copolymer was n= ²⁰ _D =1.539, and the specific gravity was 1.11.

From the above, it is clear that the polymer obtained in Example 2 has a higher refractive index than that of Comparative Example 3.

Example 3 Structural formula 22.54 g of 2-mercaptoethyl thioester methacrylate, 30.92 g of isophorone diisocyanate, and 6.54 g of ethanedithiol,
The mixture was thoroughly mixed with 40 g of styrene, and a thiourethane reaction and polymerization were carried out in the same manner as in Example 1 to obtain a concave lens made of a transparent copolymer with a center thickness of 2.0 mm and a diameter of 80 mm. Here, a = 0.14 mol, b = 0.28 mol, c = 0.14 mol, α = 2.00, β
= 1.00, and the proportion of styrene as the D component is 4 relative to the entire monomer.The refractive index of this lens is
n _D ²⁰ 0% by weight Further, when this concave lens was subjected to an impact resistance test in the same manner as in Example 1, no crushing occurred and it was found that it had excellent impact resistance.

Example 4 2-hydroxyethyl methacrylate 23.9g
, 43.8 g of trimer type hexamethylene diisocyanate, 2.3 g of ethanedithiol, and 30 g of styrene were thoroughly mixed, and a thiourethane reaction and polymerization were carried out in the same manner as in Example 1 to give a center thickness of 2.1 mm. A concave lens made of a transparent copolymer with a diameter of 80 mm was obtained. Here, a = 0.18 mol, b = 0.22 mol, c = 0.049 mol, α = 4.49, β
= 1.04, and the proportion of styrene as component D is 30% by weight based on the total monomer.

The refractive index of this lens was ²⁰ _D = 1.545, and the specific gravity was 1.17.

Further, when this concave lens was subjected to an impact resistance test in the same manner as in Example 1, no crushing occurred, and it was found that it had excellent impact resistance.

Comparative example 4 2-hydroxyethyl methacrylate 24.2g
, 44.6g of trimer type hexamethylene diisocyanate, 1.2g of ethylene glycol,
The mixture was thoroughly mixed with 30 g of styrene, and a thiourethane reaction and polymerization were carried out in the same manner as in Example 1 to obtain a copolymer. Here, a=0.19 mole,
b=0.23 mol, c=0.039 mol, α=5.90, β=
0.99, and the proportion of styrene as component D is 30% by weight based on the total monomer.

The refractive index of this copolymer was n= ^20D ₌ 1.539, and the specific gravity was 1.17.

From the above, it is clear that the polymer obtained in Example 4 has a higher refractive index than that of Comparative Example 4.

Example 5 20.0g of 2-hydroxyhalmethacrylate,
34.0 g of isophorone diisocyanate, 6.0 g of 2. mercaptoethanol, and 40 g of styrene were thoroughly mixed, and a thiourethane reaction and polymerization were performed by the method similar to Example 1 to obtain a material with a center thickness of 2.0 mm.
A concave lens made of transparent polymer with a diameter of 75 mm was obtained. Here, a=0.15 mol, b=0.31 mol, c=
0.15 mol, α=2.07, β=1.00, and the proportion of styrene as component D is 40% by weight based on the total monomer.

The refractive index of this lens is n ²⁰ _D = 1.545, and the specific gravity is 1.12.
It was hot.

Further, when this concave lens was subjected to an impact resistance test in the same manner as in Example 1, no crushing occurred, and it was found that it had excellent impact resistance.

From the above, it is clear that the polymer obtained in Example 5 has a higher refractive index than that of Comparative Example 3.

Claims (1)

[Claims] 1. The following A component, the following B component and C component,
The total number of moles of the thiol group and hydroxyl group of the A component is a, the number of moles of the isocyanate group of the B component is b,
And when the total number of moles of the thiol group and hydroxyl group of component C is c, the relative proportion that the value of the ratio b/c is greater than 1 and the value of the ratio (a+c)/b is 0.5 to 2.0. In addition to reacting with
A plastic lens material comprising a copolymer obtained by polymerization with component D below in a proportion of 20 to 50% by weight. Component A: Acrylic ester or methacrylic ester monomer having a thiol group or hydroxyl group in the molecule. Component B: Polyisocyanate compound having multiple isocyanate groups in the molecule. Component C: Aliphatic mercapto alcohol or aliphatic dithiol compound D. Component: Aromatic vinyl compound copolymerizable with component A