JP3279784B2 - Composition for plastic lens, lens, and method for producing them - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has good optical properties for use in various optical lenses such as spectacle lenses.
A plastic lens having a small specific gravity and extremely excellent impact resistance, and a lens composition for producing the lens;
Furthermore, the present invention relates to a method for producing them.

[0002]

2. Description of the Related Art Plastic lenses are lighter and harder to break than inorganic lenses and can be dyed, and have recently been rapidly used in optical elements such as spectacle lenses and camera lenses. Currently, resins widely used for these purposes include diethylene glycol bis (allyl carbonate)
(Hereinafter referred to as DAC) by radical polymerization. This resin has various characteristics such as being excellent in impact resistance, being lightweight, being excellent in dyeing properties, being excellent in workability such as cutting property and polishing property, and the like. . However, this resin has a smaller refractive index, n _D = 1.50, than that of an inorganic lens (n _D = 1.52), and in order to obtain optical characteristics equivalent to a glass lens, the center thickness, edge thickness, and curvature of the lens are required. Must be increased, and it is inevitable that the overall thickness will increase. For this reason, a lens resin having a higher refractive index has been desired.

[0003] Polyurethane-based lenses are known as lenses having a higher refractive index than DAC resins. The present inventors have proposed, for example, Japanese Patent Application Laid-Open
JP-A-63-46213 proposes a polyurethane-based lens made of a polymer of a xylylene diisocyanate compound and a polythiol compound, and is widely used as an optical lens such as an eyeglass lens. Also, JP-A-2-27
JP 0859 proposes a polyurethane lens having a high refractive index, light weight and excellent impact resistance by combining a specific polythiol compound and an isocyanate compound.
However, although these plastic lenses have a lower specific gravity than glass,
It has a specific gravity of 1.3 or more, and it cannot be said that the specific gravity is still sufficiently small. Also, because it is a urethane lens,
Although the impact resistance is better than glass and other lenses, if a hard coat or anti-reflection coat is applied, the impact resistance will be reduced, so the base material will have very good impact resistance. If not, sufficient impact resistance cannot be obtained when the lens is formed. Therefore, further improvement has been desired to solve these problems.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a plastic lens having good optical properties, low specific gravity, and extremely excellent impact resistance.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention includes an isocyanate compound containing at least one alicyclic isocyanate compound represented by the general formula (1) (formula 3) and a thiol compound represented by the formula (2) (formula 3). The present invention relates to a lens composition, a lens made of a urethane-based resin obtained by polymerizing the composition, and a method for producing the same.

[0006]

Embedded image

Hereinafter, the present invention will be described in detail. The lens composition of the present invention comprises at least one isocyanate compound containing an alicyclic isocyanate compound represented by the general formula (1) and a thiol compound represented by the formula (2). General formula (1) used in the present invention
As the isocyanate compound containing the alicyclic isocyanate compound represented by the general formula (1), not only the alicyclic isocyanate compound represented by the general formula (1), but also for adjusting the physical properties of the target urethane resin, or In order to facilitate the handling and workability of the monomer, a mixture of an alicyclic isocyanate compound represented by the general formula (1) and another isocyanate compound is also included. The alicyclic isocyanate compound represented by the general formula (1) used in the present invention has several isomers depending on the substitution positions of two isocyanate groups, but from the viewpoint of easy availability and the like. , Dicyclomethane-4,4'-diisocyane
And 4,4-isopropylidenebis (cyclohexyl isocyanate) are preferably used.

The isocyanate compound other than the alicyclic isocyanate compound represented by the formula (1) includes, for example, ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexa- isocyanate. Methylene diisocyanate, aliphatic polyisocyanate such as 2,4,4-trimethylhexamethylene diisocyanate,
Fats such as isophorone diisocyanate, bis (isocyanatomethyl) cyclohexane, 2,5-bis (isocyanatomethyl) bicyclo [2,2,1] heptane and 2,6-bis (isocyanatomethyl) bicyclo [2,2,1] heptane Examples thereof include aromatic polyisocyanates, phenylene diisocyanate, tolylene diisocyanate, aromatic isocyanates such as 4,4-diphenylmethane diisocyanate, and xylylene diisocyanate. Some of these are commercially available. Of these, isophorone diisocyanate is preferably used.

The amount of the other isocyanate compound used together with the alicyclic isocyanate compound represented by the formula (1) is appropriately determined depending on required physical properties or workability. It is usually in the range of 0 to 80% by weight, preferably in the range of 0 to 50% by weight, based on the alicyclic isocyanate compound represented. On the other hand, 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane represented by the formula (2) is disclosed in
It is easily produced by the method described in JP-A-70859, that is, a method in which epihalohydrin is reacted with 2-mercaptoethanol and then thiourea. In the lens composition of the present invention, the ratio of the isocyanate compound to the polythiol compound used is such that the molar ratio of the NCO / SH functional group is usually in the range of 0.5 to 3.0, preferably 0.5 to 3.0.
It is in the range of 1.5.

The urethane-based plastic lens resin of the present invention is obtained by heating and curing an isocyanate compound containing an alicyclic isocyanate compound represented by the formula (1) and a polythiol compound represented by the formula (2). Manufactured.
At this time, in order to adjust the polymerization rate to a desired reaction rate, a known reaction catalyst used in the production of S-alkyl thiocarbamate or polyurethane may be appropriately added. Also according to the purpose, as in the known molding method, it is also possible to add various substances such as a chain extender, a crosslinking agent, a light stabilizer, an ultraviolet absorber, an antioxidant, an oil-soluble dye, and a filler. Good.

The lens of the present invention is usually obtained by cast polymerization. Specifically, an isocyanate compound containing at least one alicyclic isocyanate compound represented by the formula (1) and a polythiol compound represented by the formula (2) are mixed. This mixed solution is defoamed by an appropriate method, if necessary, and then poured into a mold, and is usually gradually heated from a low temperature to a high temperature for polymerization. The resin for a urethane-based lens of the present invention obtained in this manner has a high refractive index, low dispersion, excellent heat resistance, excellent weather resistance, and particularly has characteristics of being lightweight and having extremely excellent impact resistance. It is suitable as a material for optical elements such as eyeglass lenses and camera lenses. Further, the lens of the present invention, if necessary, antireflection, imparting high hardness, improving abrasion resistance, improving chemical resistance, imparting antifogging properties,
Alternatively, physical or chemical treatments such as surface polishing, antistatic treatment, hard coat treatment, anti-reflection coat treatment, dyeing treatment, light control treatment and the like can be performed in order to improve the fashionability.

[0012]

The present invention will be described below in more detail with reference to examples and comparative examples. In the performance tests of the obtained resin for lenses, the refractive index, Abbe number, heat resistance, appearance, and impact resistance were evaluated by the following test methods. Refractive index, Abbe number: Measured at 20 ° C. using a Pulfrich refractometer. Heat resistance: Using a thermomechanical analyzer [manufactured by PerkinElmer (USA)], 5 g of weight was applied to the test piece,
Heating was performed at 2.5 ° C./min, and the thermal deformation onset temperature was measured.・ Appearance: Observed visually.・ Impact resistance: From the position of height 127cm (50 inches)
An iron ball having a different weight was dropped on the center of a lens having a center thickness of 1.5 mm, and a test was made to see if the lens was broken. The test was performed on ten lenses, and it was examined how many lenses were broken.

Example 1 78.7 parts (0.3 mol) of dicyclohexylmethane-4,4'-diisocyanate and 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane 5
2.1 parts (0.2 mol) and 0.1% by weight of dibutyltin dilaurate (based on the whole mixture) were mixed to form a uniform liquid, which was sufficiently defoamed and then subjected to a mold release treatment. It was injected into a mold made of a gasket. Then, while gradually raising the temperature from 30 ° C. to 130 ° C., 24
Heat-cured over time. After the completion of the polymerization, the mixture was gradually cooled, and the polymer was taken out of the mold. The obtained resin was colorless and transparent, and had a refractive index n _d = 1.60 and an Abbe number ν _d = 42. The specific gravity was 1.22, and the thermal deformation onset temperature was 127 ° C. For the impact resistance test, an iron ball weighing 225 g was dropped from a position having a height of 127 cm onto ten lenses having a center thickness of 1.5 mm, but no lens was broken.

Example 2 43.5 parts (0.16 mol) of dicyclohexylmethane-4,4'-diisocyanate, 43.5 parts (0.20 mol) of isophorone diisocyanate and 1,2-bis [(2-mercapto Ethyl) thio] -3-mercaptopropane (63.0 parts (0.24 mol) and dibutyltin dilaurate 0.1% by weight (based on the whole mixture) were mixed to form a uniform liquid, and after sufficient defoaming, It was injected into a mold composed of a glass mold and a gasket that had been subjected to a release treatment. Next, while gradually raising the temperature from 30 ° C. to 130 ° C., it was heated and cured for 24 hours. After the completion of the polymerization, the mixture was gradually cooled, and the polymer was taken out of the mold. The obtained resin was colorless and transparent, and had a refractive index n _d = 1.60 and an Abbe number ν _d = 40. The specific gravity was 1.23, and the heat deformation starting temperature was 130 ° C. 10 for impact resistance test
When an iron ball with a weight of 112 g is dropped on a 1.5 mm thick lens from a position of 127 cm in height, five of the ten pieces are broken, but a 67 g iron ball is dropped. When,
No lenses were broken.

Comparative Example 1 According to Example 9 of JP-A-2-70859, 94.0 parts (0.5 mol) of m-xylylene diisocyanate were used.
1,2-bis [(2-mercaptoethyl) thio] -3-
After mixing 87.0 parts (0.33 mol) of mercaptopropane to make a uniform liquid, the mixture was poured into a mold having a release-treated glass mold and a gasket. Then
While gradually raising the temperature from 30 ° C. to 120 ° C., the composition was cured by heating over 24 hours. After the completion of the polymerization, the mixture was gradually cooled, and the polymer was taken out of the mold. The obtained resin was colorless and transparent, and had a refractive index n _d = 1.66 and an Abbe number ν _d = 33. The specific gravity is 1.35, which is heavier than the resin of Example 1,
The heat deformation starting temperature was 98 ° C. For the impact resistance test, 127 sheets with a height of 127
Dropping an iron ball weighing 225 g from the position of cm, 1
Of the 0 sheets, 10 were broken. Next, when an iron ball having a weight of 67 g was dropped, five out of ten pieces were broken. The impact resistance was inferior to the resin of Example 1.

Comparative Example 2 111.1 parts (0.5 mol) of isophorone diisocyanate were prepared according to Example 10 of JP-A-2-70859.
1,2-bis [(2-mercaptoethyl) thio] -3-
After mixing 87.0 parts (0.33 mol) of mercaptopropane to make a uniform liquid, the mixture was poured into a mold having a release-treated glass mold and a gasket. Then
While gradually raising the temperature from 30 ° C. to 120 ° C., the composition was cured by heating over 24 hours. After the completion of the polymerization, the mixture was gradually cooled, and the polymer was taken out of the mold. The obtained resin was colorless and transparent, had a refractive index n _d = 1.60 and an Abbe number ν _d = 40. The specific gravity was 1.24, which was heavier than the resin of Example 1, and the thermal deformation onset temperature was 142 ° C. For the impact resistance test, 127 sheets with a height of 127
Dropping an iron ball weighing 225 g from the position of cm, 1
Of the 0 sheets, 10 were broken. Next, when an iron ball weighing 67 g was dropped, two of the ten pieces were broken. The impact resistance was inferior to the resin of Example 1.

Comparative Example 3 According to Example 11 of JP-A-2-70859, 1,4-
Bis (isocyanatomethyl) cyclohexane 96.1
Part (0.5 mol) and 87.0 parts (0.33 mol) of 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane to obtain a uniform liquid, and then release. It was injected into a mold consisting of a treated glass mold and a gasket. Next, while gradually raising the temperature from 30 ° C. to 120 ° C., the mixture was cured by heating for 24 hours. After the completion of the polymerization, the mixture was gradually cooled, and the polymer was taken out of the mold. The obtained resin is colorless and transparent and has a refractive index n _d = 1.6.
2, Abbe number ν _d = 39. The specific gravity was 1.29, which was heavier than the resin of Example 1, and the thermal deformation starting temperature was 106 ° C. For the impact resistance test, weighing 225 g from a position of 127 cm height on ten 1.5 mm thick lenses
When the iron balls were dropped, ten of the ten were broken. Next, when an iron ball weighing 67 g was dropped, five out of ten pieces were broken. The impact resistance was inferior to the resin of Example 1.

[0018]

The lens made of the urethane resin of the present invention has good optical properties, low specific gravity, and extremely excellent impact resistance.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08G 18/00-18/87 G02B 1/04 G02C 7/02

Claims (6)

(57) [Claims] 1. At least one kind of the general formula (1)
An alicyclic isocyanate compound represented by the following formula: Wherein R and R ′ each represent a hydrogen atom or a methyl group, and an isocyanate compound of the formula (2)
The composition for plastic lenses containing the polythiol compound represented by these. Embedded image 2. An isocyanate compound containing at least one alicyclic isocyanate compound represented by the general formula (1) and isophorone diisocyanate, and a polythiol compound represented by the formula (2). Composition for plastic lenses. 3. The molar ratio of NCO groups / SH groups is from 0.5 to
3. The composition for a plastic lens according to claim 1, wherein the ratio is 3.0. 4. A plastic lens comprising a urethane resin obtained by polymerizing the plastic lens composition according to claim 1. 5. A method for producing a resin for a urethane-based plastic lens, wherein the composition for a plastic lens according to claim 1 is cured by heating. 6. A method for producing a plastic lens comprising a urethane resin, wherein the composition for a plastic lens according to claim 1 is cast-polymerized.