JP3245535B2 - Optical resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an optical resin and a plastic lens made of the optical resin.

[0002]

2. Description of the Related Art Plastics have been used in recent years for optical components such as lenses for spectacles because plastics are lighter, harder to break, and easier to dye than glass. Typical plastic materials for the above purpose include poly (diethylene glycol bisallyl carbonate) (hereinafter abbreviated as CR-39) and polymethyl methacrylate. However, since these plastics have a low refractive index of around 1.50, when a strong lens is manufactured, the center thickness and Yuba thickness of the lens increase,
An increase in weight and a decrease in beauty were not avoided.

Therefore, there is a strong demand for a plastic material having a low refractive index and a high refractive index capable of reducing the thickness. Examples of such a high refractive index material include a polymer of xylylene diisocyanate (XDI) and 1,2-bis (mercaptoethylthio) -3-mercaptopropane, and a polymer of XDI and 2,5-bis (mercaptomethyl)- 1,
There are polymers such as 4-dithiane. The refractive index of each of these polymers is as high as 1.66. However, although the Abbe number (dispersion index) is 32, which is relatively high for the high refractive index compared with the conventional product, it is still not enough. Further, since the heat resistance temperature is 100 ° C. or lower, the lens may be deformed or the inorganic antireflection film may be cracked at a high temperature such as in a car in the middle of summer.

Accordingly, an object of the present invention is to provide an optical resin having a high refractive index, a high Abbe number, and a high heat resistance temperature, and a plastic lens made of the optical resin.

[0005]

Means for Solving the Problems As a result of repeated studies to achieve the above object, the present inventor has a dithiane ring at the center of the molecule, and a vinylthioalkyl group is substituted at the 2,5-position of the dithiane ring. Polyvinyl compound (A) and 2
At least a polyisocyanate compound (B) having at least two isocyanate groups and a polythiol compound (C) having a dithiane ring at the center of the molecule and having a mercaptoalkyl group substituted at the 2,5-position of the dithiane ring By reacting the mixture, it has been found that an optical resin having a high refractive index and a high Abbe number, a high heat resistance temperature can be obtained, and that a plastic lens can be easily obtained from the optical resin. .

Accordingly, the present invention provides a compound represented by the general formula (I)

Embedded image (Where m is an integer of 1 to 3), a polyvinyl compound (A), a polyisocyanate compound (B), and a general formula (II)

Embedded image (Wherein, n is an integer of 1 to 2). A gist is an optical resin obtained by reacting a mixture containing at least a polythiol compound (C) represented by the following formula:

The present invention also provides a plastic lens made of the above optical resin.

[0008]

The reason why the optical resin of the present invention has a high refractive index, a high Abbe number and a high heat-resistant temperature is presumed as follows.

First, the refractive index will be described. The optical resin of the present invention comprises a polyvinyl compound (A) of the general formula (I) and a polythiol compound (C) of the general formula (II) as monomer components. The compound (A) of the general formula (I) and the compound (C) of the (II), which are the above monomer components, each have a dithiane ring containing two sulfur atoms in the molecule, and are substituted by the dithiane ring. In addition, each of the two side chain groups also contains one sulfur atom and has a high sulfur content in the molecule, and thus is itself a high refractive index substance. Therefore, the optical resin of the present invention containing these high refractive index compounds (I) and (II) as a monomer component also has a high refractive index.

Next, the Abbe number will be described. In the optical resin of the present invention, an aromatic compound having a large molecular dispersion is not used as a monomer. Since the compound (A) of (I) and the compound (C) of the general formula (II) are monomer components, the compound has a high Abbe number (low dispersibility).

Finally, regarding the heat resistance, the compounds (A) of the general formula (I) and the compound (C) of the (II), which are monomer components, each have a dithiane ring having excellent heat resistance. Therefore, these compounds (A) and (C)
The optical resin of the present invention, which has a monomer component, also has a high heat resistance temperature and is excellent in heat resistance.

The optical resin of the present invention has, for example, a refractive index of 1.64 or more, an Abbe number of 38 or more, and a heat-resistant temperature of 100 ° C. or more.

Since the optical resin of the present invention uses the above compounds (A), (B) and (C) as monomer components, it has excellent weather resistance, impact resistance and processability in addition to the above-mentioned properties. ing.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The optical resin of the present invention comprises a polyvinyl compound (A) represented by the general formula (I), a polyisocyanate compound (B), and a polythiol compound (C).
Is obtained by reacting a mixture containing at least

Specific examples of the polyvinyl compound (A) represented by the general formula (I) include 2,5-bis (2-thia-3
-Butenyl) -1,4-dithiane (m = 1 in the general formula (I)), 2,5-bis (3-thia-4-pentenyl) -1,4-dithiane (m = 2), 2,5 -Screw (4
-Thia-5-hexanyl) -1,4-dithiane (m =
3) and the like.

As the polyisocyanate compound (B), alicyclic or aliphatic polyisocyanates can be used, and specific examples thereof include isophorone diisocyanate, bis (isocyanatomethyl) cyclohexane, tris (isocyanatomethyl) cyclohexane, and cyclohexane. Diisocyanate, cyclohexane triisocyanate, dicyclohexylmethane diisocyanate,
Examples include bicycloheptane diisocyanate, hexamethylene triisocyanate, and lysine ester triisocyanate. The glass transition point (T
It is preferable to use at least an alicyclic polyisocyanate in terms of g) and increasing the refractive index.

Specific examples of the polythiol compound (C) represented by the general formula (II) include 2,5-bis (mercaptomethyl) -1,4-dithiane (n in the general formula (II)
= 1), 2,5-bis (mercaptoethyl) -1,4-
And dithiane (n = 2).

Among the above monomer components, the vinyl group in the polyvinyl compound (A) of the general formula (I) and the isocyanate group in the polyisocyanate compound (B) are converted into the polythiol compound (C) in the general formula (II). The optical resin of the present invention is obtained by reacting with the mercapto group. Therefore, the mixing ratio of the polyvinyl compound (A), the polyisocyanate compound (B), and the polythiol compound (C) is (the number of vinyl groups + the isocyanate compound). When expressed by the number of groups / (the number of mercapto groups), it is preferable to define the number in the range of 0.8 to 1.2. If the reason is out of this range,
A large amount of any one of the functional groups remains in the resin, resulting in a large decrease in physical properties accompanied by a decrease in the glass transition point (Tg) of the resin, a decrease in the degree of crosslinking, a decrease in chemical resistance and weather resistance. On the other hand, if it is 0.8 to 1.2, there is no such problem. The value of (number of vinyl groups + number of isocyanate groups) / (number of mercapto groups) is 0.1.
95 to 1.05 is particularly preferred.

The production of the optical resin of the present invention is carried out as follows. First, a mixture containing at least the polyvinyl compound (A), the polyisocyanate compound (B) and the polythiol compound (C) of the general formula (I) is prepared. This mixture can contain, in addition to the compounds (A), (B) and (C), an ultraviolet absorber, an antioxidant, a colorant, an internal mold release agent, and a polymerization catalyst.

Examples of ultraviolet absorbers for improving weather resistance include benzophenones such as 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone, and 2- (2'-hydroxy-5'-methylphenyl). ) Benzotriazole, 2- (2′-hydroxy-)
5'-t-octylphenyl) benzotriazole and other benzotriazole-based ultraviolet absorbers;
The amount of addition is 0.01 to 0,0 to the total weight of the mixture.
It is preferably 50%, particularly preferably 0.05 to 0.20%.

Examples of the internal release agent for accelerating the release of the polymer in the casting polymerization include mono- or dimethoxyethyl acid phosphate, mono- or diethoxyethyl acid phosphate, mono- or dipropoxyethyl acid phosphate, mono- or dibutoxy acid. Ethyl acid phosphate, mono or dipentyloxyethyl acid phosphate, mono or dihexyloxyethyl acid phosphate, mono or dioctyloxyethyl acid phosphate and mixtures thereof.
The addition amount is 10 to 1000 with respect to the total weight of the mixture.
0 ppm is preferable, and 50 to 5000 ppm is particularly preferable.

Examples of the polymerization catalyst for accelerating the polymerization reaction include monomethyltin trichloride, dimethyltin dichloride, trimethyltin chloride, dibutyltin dichloride, tributyltin chloride, tributyltin fluoride, dimethyltin dibromide and the like. The amount of the catalyst used depends on the type of the monomer used and the polymerization temperature, but is generally preferably from 10 to 10,000 ppm in the monomer mixture, and is preferably from 50 to 8,000 ppm.
pm is particularly preferred. If the amount is out of the range of 10 to 10000 ppm, it is difficult to adjust the polymerization rate, and optical distortion and striae increase, which is not suitable for optical use. In order to control the reaction between the vinyl group and the mercapto group, quinones such as hydroquinone monomethyl ether may be added.

The polymerization reaction is carried out by heating the mixture. When the optical resin of the present invention is manufactured as a plastic lens, cast polymerization is preferred. In this casting polymerization, a mixture containing at least the monomer compounds (A), (B) and (C) is degassed, and then poured into a mold combining a glass or metal mold and a resin gasket. The polymerization is carried out. In order to improve the releasability of the polymer mold, the surface of the mold may be treated with an external release agent. The polymerization time and the polymerization temperature depend on the type of the monomer used, but are generally from 3 to 96 hours, from 0 to 96 hours.
130 ° C.

[0024]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

The refractive index, Abbe number, specific gravity, transparency, weather resistance, heat resistance, impact resistance, and workability of the resin for lenses obtained in Examples and Comparative Examples were evaluated according to the following methods. .

Refractive index / Abbe number: Measured at 20 ° C. using KPR200 manufactured by Calnew Optical Co., Ltd.

Specific gravity: Measured by Archimedes' method. The measurement temperature is 20 ° C.

Transparency: Visual observation in a dark place, under fluorescent light,
A lens having no clouding and no opaque substance deposition was evaluated as good (）), and one having a clear lens was evaluated as poor (×).

Weather resistance: The hue was compared with that before the test when 200 hours had passed after the lens was set on a weather meter equipped with a xenon lamp. The evaluation criteria were as follows: almost no change was good (○), slight yellowing was possible (△),
The yellowing was evaluated as poor (x).

Impact resistance: A minus lens (approximately D-300) having a center thickness of 1.0 mm was prepared and evaluated in accordance with the measurement method of the FDA standard. (X) and those that did not crack were (o).

Heat resistance: TAS100TMA manufactured by Rigaku Corporation
Penetration method (specimen thickness 3 mm, pin diameter 0.5 m
m, a load of 10 g, and a temperature rising rate of 10 ° C./min) were used to measure the temperature at which the pins started to be fitted.

Machinability: Cut with a razor processing machine (RE-2000 (manufactured by HOYA Co., Ltd.)) for processing eyeglass lenses. Those that could not be processed were marked (x).

Example 1 As a polyvinyl compound (A), 16.40 parts by weight of 2,5-bis (2-thia-3-butenyl) -1,4-dithiane (TBD) was added to a polyisocyanate compound (B).
30.91 parts by weight of tris (isocyanatomethyl) cyclohexane (HMTI) and 52.67 parts by weight of 2,5-bis (mercaptomethyl) -1,4-dithiane (DMMD) as polythiol compound (C)
And 1000 ppm of dimethyltin dichloride (DMTDCl) as a polymerization catalyst, and 1000 ppm of a mixture of monobutoxyethyl acid phosphate and dibutoxyethyl acid phosphate (4: 6) as an internal release agent. A mixture was prepared. The obtained monomer mixture is poured into a mold for lens production in which a metal (or plastic) mold and a resin gasket are combined, and the mixture is added at 20 ° C. for 6 hours.
4 hours at 0 ° C, 4 hours at 40 ° C, 3 hours at 60 ° C, 8
After polymerization at 0 ° C. for 2 hours and at 120 ° C. for 3 hours, the obtained polymer was removed from the mold and examined for the various physical properties described above. Table 1 shows the results.

Examples 2 to 4 Example 1 was repeated except that the polyvinyl compounds (A), the polyisocyanate compounds (B) and the polythiol compounds (C), and the polymerization catalysts and internal release agents described in Table 1 were used. In the same manner, a polymer was obtained, and various physical properties of the obtained polymer were examined. The results are shown in Table 1.

Comparative Examples 1 to 6 A monomer mixture lacking at least one of the polyvinyl compound (A), the polyisocyanate compound (B) and the polythiol compound (C) was prepared, and the obtained monomer was used in the same manner as in Example 1. Under the conditions described above, a polymer was obtained. Various physical properties of the obtained polymer were examined. Table 2 shows the results.

[0036]

[Table 1]

[0037]

[Table 2]

The following is evident from Tables 1 and 2. (1) The optical resins (plastic lenses) of Examples 1 to 4 using the polyvinyl compound (A), the polyisocyanate compound (B) and the polythiol compound (C) as monomer components have a refractive index of 1.64 to 1. It has a high refractive index of 65 and an Abbe number of 38, which is a high Abbe number. Further, the heat resistance temperature is 100 to 123 ° C., and the heat resistance is excellent. Furthermore, it has excellent transparency, weather resistance, impact resistance, and workability.

(2) On the other hand, the polyvinyl compound (A) is not used, and the polythiol compound does not have a dithiane ring, and is therefore not included in the polythiol compound (C) of the present invention. The polymers of Comparative Examples 1-2 obtained using (mercaptoethylthio) -3-mercaptopropane (DMETMP) and pentaerythritol tetrakis-3-mercaptopropionate (PETMP) have high refractive index and high Abbe number. Simultaneous achievement was impossible, and heat resistance and weather resistance were poor.

The polymer of Comparative Example 3 obtained by homopolymerizing 2,5-bis (2-thia-3-butenyl) -1,4-dithiane (TBD) contained in the polyvinyl compound (A) is as follows: The impact resistance was remarkably inferior.

Further, together with the above-mentioned TBD contained in the polyvinyl compound (A) and 2,5-bis (mercaptomethyl) -1,4-dithiane (DMMD) contained in the polythiol compound (C), only these are polymerized. The polymer of Comparative Example 4 obtained was inferior in transparency and processability.

Further, p-xylylenedithiol (XDT) not contained in the polythiol compound (C) was used together with the above-mentioned TBD contained in the polyvinyl compound (A), and the polymer of Comparative Example 5 was obtained by polymerizing only these. The product was also inferior in transparency and processability.

Further, m-xylylene diisocyanate (XDI) which is a polyisocyanate compound and polythiol compound (C) are used without using the polyvinyl compound (A).
The polymer of Comparative Example 6 obtained by polymerizing 2,5-bis (mercaptomethyl) -1,4-dithiane (DMMD) was inferior in heat resistance, weather resistance, impact resistance and workability. .

[0044]

As described above, according to the present invention, an optical resin having a high refractive index, a high Abbe number and a high heat resistance temperature, and a plastic lens made of the optical resin are provided.

Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 18/00-18/87 G02B 1/04 G02B 3/00

Claims (2)

(57) [Claims] 1. A compound of the general formula (I) (Wherein m is an integer of 1 to 3), a polyvinyl compound (A), a polyisocyanate compound (B), and a compound represented by the general formula (II): (Where n is an integer of 1 to 2) an optical resin obtained by reacting a mixture containing at least a polythiol compound (C) represented by the following formula: 2. A plastic lens comprising the optical resin according to claim 1.