JPH0763902A - Composition for plastic lens and production of plastic lens - Google Patents

Abstract

PURPOSE:To obtain a compsn. for plastic lens which shows little change in the viscosity with the lapse of time excellent workability, and little generation of optical strain and is practical by incorporating a specified alkyl tin halide compd. into a monomer mixture comprising aliphatic polyisocyanate and a specified polythiol compd. CONSTITUTION:The compsn. is obtd. by incorporating a component D into a nomomer mixture of a component A and component B and/or component C. The component A is an aliphatic polyisocyanate compd. having two or more isocyanate groups in one molecule. The component B is a polythiol compd. expressed by formula I. The component C is dipentaerythritol hexakis-(mercaptoacetate) expressed by formula II. The component D is an alkyl tin halide compd. expressed by formula III. In formula I, R1 is methyl group or ethyl group, (a) is an integer 0 or 1, (b) is an integer 3 or 4, and a+b=4. In formula III, R2 is methyl group, ethyl group, etc., X is fluorine atom, chlorine atom, etc., and (f) is an integer 1-3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition used for producing a plastic lens and a method for producing a plastic lens using the composition.

[0002]

It is known to react a polyisocyanate compound with a polythiol compound in order to obtain a plastic lens having a high refractive index. For example, JP-A-60-199016 discloses an aliphatic polyisocyanate compound such as xylylene diisocyanate, pentaerythritol tetrakis (mercaptoacetate),
A method for producing a polyurethane plastic lens by heating a composition obtained by mixing an aliphatic polythiol compound such as trimethylolpropane tris (mercaptoacetate) is disclosed.

[0003]

However, the plastic lens obtained by the method disclosed in the above-mentioned JP-A-60-199016 has a polymerization rate as described in JP-A-63-46213. However, there is a problem in that it is difficult to control heat during polymerization, optical distortion is large, and it is difficult to obtain a practical lens. Further, the viscosity of the composition remarkably increases with the lapse of time, and it becomes difficult to inject the composition into a mold, resulting in deterioration of workability.

The present invention has been made in order to solve the above-mentioned problems, and the viscosity increases remarkably with time, the workability is poor, and it is difficult to obtain a practical lens because of large optical distortion. Even if the composition known from Japanese Patent Laid-Open No. 63-46213 is used, a composition for a plastic lens capable of obtaining a practical lens with less optical distortion without lowering workability and productivity. Another object of the present invention is to provide a method for producing a plastic lens using the composition.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above-mentioned object, and as a result, it has been known that the viscosity increases remarkably with time, and that optical distortion is large and it is difficult to obtain a practical lens. The composition obtained by incorporating the alkyl tin halide compound of the following component (D) into the above-mentioned monomer mixture comprising the following component (A) and the component (B) and / or the component (C) has a viscosity with time. With almost no increase, workability is excellent, and when this composition is used, the polymerization rate becomes low, the occurrence of optical distortion during polymerization is extremely small, and a practical lens can be easily obtained. It has been found that no practical lens can be mass-produced without the need for precise temperature control.

The present invention has been completed based on such findings, and the composition for a plastic lens of the present invention substantially comprises the following components (A) and (B) and / or (C). The following (D) component is contained in the monomer mixture consisting of

Further, the method for producing a plastic lens of the present invention comprises adding the following component (D) to a monomer mixture consisting essentially of the following component (A), component (B) and / or component (C). The composition for a plastic lens is cast-polymerized in a mold for producing a plastic lens.

Component (A): An aliphatic polyisocyanate compound having two or more isocyanate groups in one molecule.

Component (B): General formula (I) (R ₁ ) _a -C (CH ₂ OCOCH ₂ SH) _b (I) (wherein R ₁ represents a methyl group or an ethyl group, and a is 0 to 0). 1
, B is an integer of 3 to 4, and a + b = 4. ) The polythiol compound represented by.

Component (C): Formula (II)

[Chemical 3] Dipentaerythritol hexakis- (mercaptoacetate) represented by

Component (D): General formula (III) (R ₂ ) _f --Sn--X _4-f (wherein R ₂ represents a methyl group, an ethyl group, a propyl group or a butyl group, and X represents a fluorine atom. , A chlorine atom or a bromine atom, and f is an integer of 1 to 3.).

The present invention will be described in detail below.

In the composition of the present invention, the component (A) is 1
It is an aliphatic polyisocyanate compound having two or more isocyanate groups in the molecule and is disclosed in JP-A-60-1990.
The aliphatic polyisocyanate compounds disclosed in JP-A No. 16, JP-A-57-136601, JP-A-63-46213, JP-A-1-302202 and the like can be used.

Examples of the aliphatic polyisocyanate compound having a particularly remarkable effect of the present invention include isophorone diisocyanate, bis (isocyanatomethyl) cyclohexane, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, bis (isocyanatomethyl) bicycloheptane, methylenebis (4-). Cyclohexyl isocyanate), bicycloheptane triisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, mesitylene triisocyanate and the like.

The aliphatic polyisocyanate as the component (A) can be used alone or in admixture of two or more.

In the composition of the present invention, the component (B) has the general formula (I) (R ₁ ) _a -C (CH ₂ OCOCH ₂ SH) _b (I) (wherein R ₁ is a methyl group or an ethyl group). Where a is 0 to 1
, B is an integer of 3 to 4, and a + b = 4. ), And specific examples thereof include trimethylolpropane tris- (mercaptoacetate), trimethylolethane tris- (mercaptoacetate), and pentaerythritol tetrakis- (mercaptoacetate). Of these, pentaerythritol tetrakis- (mercaptoacetate) exhibits a particularly remarkable effect.

In the composition of the present invention, the component (C) has the formula (II)

[Chemical 4] Is dipentaerythritol hexakis- (mercaptoacetate).

In order to obtain preferable physical properties as a lens such as refractive index and workability, at least one component (B) represented by the general formula (I) and / or component (A) (aliphatic polyisocyanate) are used. Alternatively, at least one kind of the component (C) represented by the formula (II) is a -NCO group / (-SH
Group) molar ratio of 0.9 to 1.2, particularly preferably 0.95
It is desirable to mix them in a ratio of ˜1.10.

The other monomer is added to the monomer composition (A).
When it is contained together with the components (C) to (C), the viscosity of the entire monomer mixture at this time largely increases with the passage of time, and therefore the addition of other monomers is not preferable. However, it is possible to add a small amount of the monomer as long as the object of the present invention of suppressing an increase in the viscosity of the composition can be sufficiently achieved.

The composition of the present invention comprises a monomer mixture containing substantially the above-mentioned component (A) and component (B) and / or component (C) and having the general formula (III) (R ₂ ) _f --Sn. -X _4-f (In the formula, R ₂ represents a methyl group, an ethyl group, a propyl group or a butyl group, X represents a fluorine atom, a chlorine atom or a bromine atom, and f is an integer of 1 to _3. ) It is characterized by containing an alkyl tin halide compound represented by

The alkyltin halide compound of the general formula (III) suppresses the viscosity change of the above-mentioned monomer mixture with time,
It also plays the role of suppressing the occurrence of optical distortion by lowering the polymerization rate during polymerization. Examples of the alkyl tin halide compound of the general formula (III) include monomethyltin trichloride,
Dimethyltin dichloride, trimethyltin chloride, dibutyltin dichloride, tributyltin chloride, tributyltin fluoride, dimethyltin dibromide and the like can be mentioned. The amount of the tin compound used depends on the type of the monomer used and the polymerization temperature, but is generally 10 to 10,000 ppm, preferably 50 to 8,000, in the monomer mixture.
It is preferable to add it in the range of 0 ppm.

When a halogen-free tin compound such as dibutyltin dilaurate is used in place of the component (D), the function and effect of the component (D) do not occur and the object of the present invention is not achieved. Can not.

In addition, in the composition of the present invention, additives such as an ultraviolet absorber and an antioxidant may be added as necessary to improve weather resistance.

In the composition of the present invention, for example, the component (D) is added in advance to any one of the components (A) to (C) at 0 ° C. to room temperature, and then the remaining components (A) to (C) are added. Is preferably prepared by mixing and stirring.

Next, a method of manufacturing the plastic lens of the present invention will be described. The method for producing a plastic lens of the present invention comprises a composition for a plastic lens in which a monomer mixture containing the component (A) and the component (B) and / or the component (C) contains the component (D). It is cast and polymerized in a mold for producing a plastic lens. As the molding die for manufacturing the plastic lens, for example, a molding die in which a glass or metal mold and a resin gasket are combined is used. The polymerization time and the polymerization temperature depend on the monomer used, but generally 3 to 96 hours, 0 to
It is 130 ° C. In order to improve the releasability of the lens after polymerization, a mold releasing agent may be applied to the molding surface of the molding die, or an internal mold releasing agent may be added to the monomer mixture.

According to the method for producing a plastic lens of the present invention, since the composition for a plastic lens containing the component (D), an alkyl tin halide compound, is cast-polymerized, an optical distortion hardly occurs and a practical lens is produced. Can be obtained.

[0027]

The present invention will be further described with reference to the following examples.

Example 1 Component (A): Bis (isocyanatomethyl) cyclohexane (hereinafter abbreviated as H6-XDI) 47.3 parts by weight Component (B): Pentaerythritol tetrakismercaptoacetate (hereinafter abbreviated as PETMA) 52. 7 parts by weight (D) component: dimethyltin dichloride (hereinafter abbreviated as DMTDCl) 0.01 parts by weight (100 ppm) 60% mixture of dibutoxyethyl acid phosphate and 40% butoxyethyl acid phosphate 0.10 parts by weight 2 -(2'-Hydroxy-5'-t-butylphenyl) benzotriazole 0.03 parts by weight (1) Measurement of pot life The above components were thoroughly stirred and mixed at room temperature to obtain a mixture 2
The sample was placed in an electric furnace kept at 0 ° C., and the time-dependent change in viscosity was examined using Viscomate VM-1A-L manufactured by Yamaichi Denki Co., Ltd. As a result, for the initial viscosity of 48.0 cps, 1.
The viscosity after 5 hours did not change at 49.0 cps, and there was no significant increase in viscosity after that, the viscosity after 5 hours was 56.0 cp.
It was s. As described above, it was revealed that the composition of this example had an extremely gentle increase in viscosity with time and a long pot life, and thus was excellent in workability.

On the other hand, with respect to the same composition except that the component (D) was not contained, the change in viscosity with time was examined in the same manner. The initial viscosity was 47.0 cps and the viscosity after 0.25 hours was 65. 0.6 cps, viscosity after 0.5 hours is 100.
It jumped to 0 cps and reached 185.0 cps one hour later.

The evaluation of the pot life is based on the initial viscosity after preparation at room temperature (20 ° C.) of 2 in the table below.
When the time until the viscosity was doubled was 2 hours or more, it was indicated as good (◯), and when it was less than 2 hours, it was indicated as bad (x).

(2) Production of plastic lens A mixture obtained by thoroughly mixing the above components at room temperature with stirring
After degassing for 60 minutes under a reduced pressure of 5 mmHg, the mixture was poured into a mold composed of a pair of glass molds and a polyethylene gasket. The pair of glass molds has an upper mold curvature of 600 mm,
Using a lower mold having a curvature of 120 mm, a molding mold was assembled so that the center thickness of the lens was 5 mm and the diameter was 75 mm.

After injecting the monomer mixture into the mold, the temperature was raised to 20 ° C. for 25 hours and then to 120 ° C. over 14 hours and polymerized at 120 ° C. for 3 hours. Took out.

Table 1 shows the results of evaluation of the refractive index, Abbe number, transparency, weather resistance, optical strain, and striae of the plastic lens obtained in this example. From Table 1, the refractive index is 1.5
6, the Abbe number was 46. In addition, there is no clouding of the lens and precipitation of opaque substances, and the transparency is good (○), there is almost no change in hue even after the weather resistance test, and the weather resistance is also good (○).
Met. Further, the plastic lens obtained in this example did not cause optical distortion and stria even though the center thickness, diameter, and peripheral thickness were large, and these evaluations were all good (◯).

The evaluation methods for refractive index, Abbe number, transparency, weather resistance, optical strain and striae are shown below.

Refractive index / Abbe number: Measured at 20 ° C. using an Abbe refractometer 2T manufactured by Atago Co.

Transparency: The obtained lens was visually observed under a fluorescent lamp in a dark place, and a lens having no cloudiness and deposition of an opaque substance was evaluated as good (○), and an apparent one was defective (x). And

Weather resistance: Set the lens on a weather meter equipped with a sunshine carbon arc lamp and set it to 2
After 00 hours, the hues before the test were compared.

The evaluation criteria were good (∘) when there was almost no change, slight yellowing (Δ) and poor yellowing (x). Note that the evaluation of (Δ) is within a practically acceptable range.

Optical distortion: Visual observation was performed with a strain scope. Those without distortion were evaluated as good (◯), and those with large distortion were evaluated as bad (x).

Striae: Visual observation by the schlieren method was performed. Those with almost no striae were rated as good (◯), and those with many striae were rated as bad (x).

Examples 2 to 11 Compositions for plastic lenses were prepared in the same manner as in Example 1 except that a predetermined amount of the monomer and the alkyl tin halide compound as the component (D) shown in Tables 1 and 2 were used. Was prepared, and the pot life was measured and the plastic lens was manufactured. The results of evaluating the physical properties of the obtained plastic lens are shown in Tables 1 and 2. From Tables 1 and 2, the compositions of Examples 2 to 11 have long pot lives, and the plastic lenses obtained have all the tests of refractive index, Abbe number, transparency, weather resistance, optical strain, and striae. The items were satisfactory.

[0042]

[Table 1]

[0043]

[Table 2]

Comparative Examples 1 to 6 Compositions shown in Table 3 which do not contain the alkyltin halogen compound of the component (D) and compositions shown in Table 3 in which a halogen-free tin compound is used in place of the component (D). Were prepared, and the pot life was measured and the plastic lens was manufactured. Table 3 shows the physical properties of the obtained plastic lens. From Table 3, the compositions of Comparative Examples 1 to 6 all had a short pot life of 2 hours or less (evaluation x) and were inferior in workability. Further, the plastic lenses obtained from the compositions of Comparative Examples 1 to 6 were found to have optical distortion and striae (evaluation x).

[0045]

[Table 3]

[0046]

According to the present invention, by incorporating a specific alkyltin halide compound into a monomer mixture consisting essentially of an aliphatic polyisocyanate and a specific polythiol compound, it is possible to reduce the change in viscosity with time. Provided is a composition for a plastic lens, which has excellent properties and is capable of obtaining a practical plastic lens with less optical distortion.

Further, according to the present invention, there is provided a practical method for producing a plastic lens in which optical distortion is small even when the center thickness, the diameter and the peripheral thickness are large.

Claims (3)

[Claims] 1. A plastic lens comprising a monomer mixture consisting essentially of the following component (A) and the component (B) and / or component (C) containing the following component (D). Composition. Component (A): An aliphatic polyisocyanate compound having two or more isocyanate groups in one molecule. Component (B): general formula _{(I) (R 1) a} -C in _{(CH 2 OCOCH 2 SH) b} (I) ( wherein, R ₁ represents a methyl group, an ethyl group, a is 0-1
, B is an integer of 3 to 4, and a + b = 4. ) The polythiol compound represented by. Component (C): Formula (II) Dipentaerythritol hexakis- (mercaptoacetate) represented by Component (D): Formula (III) (R ₂₎ in _{f -Sn-X 4-f} (wherein, R ₂ represents a methyl group, an ethyl group, a propyl group or a butyl group, X represents a fluorine atom, a chlorine atom , A bromine atom, and f is an integer of 1 to 3.). 2. The component (D) is added in an amount of 10 to 1 in the monomer mixture.
The composition for a plastic lens according to claim 1, wherein the composition has a content of 10,000 ppm. 3. A plastic lens composition comprising a monomer mixture consisting essentially of the following component (A) and the component (B) and / or component (C) containing the following component (D): A method for producing a plastic lens, which comprises casting and polymerizing in a lens production mold. Component (A): An aliphatic polyisocyanate compound having two or more isocyanate groups in one molecule. Component (B): general formula _{(I) (R 1) a} -C in _{(CH 2 OCOCH 2 SH) b} (I) ( wherein, R ₁ represents a methyl group, an ethyl group, a is 0-1
, B is an integer of 3 to 4, and a + b = 4. ) The polythiol compound represented by. Component (C): Formula (II) Dipentaerythritol hexakis- (mercaptoacetate) represented by Component (D): Formula (III) (R ₂₎ in _{f -Sn-X 4-f} (wherein, R ₂ represents a methyl group, an ethyl group, a propyl group or a butyl group, X represents a fluorine atom, a chlorine atom , A bromine atom, and f is an integer of 1 to 3.).