JP2002082201A - Synthetic resin lens and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Problem] A synthetic resin having a high refractive index and a high Abbe number, having characteristics required for an optical lens such as impact resistance and dyeing properties, and capable of photopolymerization as well as thermal polymerization. Provide lenses made of SOLUTION: Bis-2 represented by the following structural formula (1)
20-80% by weight of methacryloylthioethyl sulfide, 5-50% by weight of difunctional or higher thiol, and
A synthetic resin lens having a refractive index of 1.58 or more and an Abbe number of 35 or more, which is a copolymer obtained by copolymerizing a composition comprising 0 to 75% by weight of a monomer copolymerizable therewith. . CH ₂ = C (CH ₃ ) CO-S-CH ₂ CH ₂ -S-CH ₂ CH ₂ -S-COC (CH ₃ ) = CH ₂ Structural formula (1)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin lens, and more particularly to a synthetic resin lens made of a photopolymerizable composition having good optical properties, dyeing properties and impact resistance. It is.

[0002]

2. Description of the Related Art Conventionally, various inorganic glasses and synthetic resins have been used as optical lens materials. Various physical properties are required for optical lens materials. For example, in the field of spectacle lenses, high refractive index, high Abbe number, and low specific gravity are extremely important. In other words, if the lens used has a high refractive index and a low specific gravity, the lens can be made thinner and lighter, and if the lens has a high Abbe number, light dispersion is small and a comfortable wearing feeling can be obtained. Because.

[0003] For this reason, materials for spectacle lenses tend to have a higher refractive index year by year, and have a lower specific gravity and a very light weight compared to inorganic glass.
This tendency is particularly remarkable.

In the field of spectacle lenses, as a material of a synthetic resin lens, there is a material called "CR-39" made from diethylene glycol bisallyl carbonate as a typical example at the beginning. The material was very lightweight compared to previous inorganic glass lenses, so it quickly penetrated the world. However, since this material has a low refractive index of about 1.50, the entire lens becomes thick, and is not satisfactory as a spectacle lens. Therefore, in order to reduce the thickness of the lens, research on increasing the refractive index has been actively conducted. As a result, for example, in a urethane resin material obtained by polymerizing thiol and isocyanate (Japanese Patent Application Laid-Open No. 2-27059), a refractive index of 1.60 or more is achieved, and further, an episulfide resin containing an episulfide compound is produced. With materials (Japanese Patent Application Laid-Open No. Hei 9-71580) and the like, the thinning of the lens was rapidly accelerated, such as achieving a refractive index of 1.70 or more.

However, the material obtained by urethane polymerization of thiol and isocyanate is a synthetic resin obtained by a urethane reaction, and a lens having a high refractive index, a high Abbe number and excellent impact resistance can be obtained. Inconvenient handling. Odor occurs during lens processing. There are problems such as poor moldability (low pass rate). Also,
At present, materials containing episulfide compounds have problems not only in odor and moldability but also in impact resistance and cost. Furthermore, these high-refractive-index and ultra-high-refractive-index resins are synthetic resins obtained by a urethane reaction and an episulfide ring-opening reaction, and since photopolymerization is difficult, both require a long heat curing time. ,
A polymerization method by thermal polymerization was required. Therefore, in the production of spectacle lenses, since the polymerization time is as long as about 10 to 20 hours, the time required to occupy the mold used in producing the lens, that is, the glass mold, is also long. Therefore, mass production of lenses requires a very large number of glass molds and large polymerization equipment, which has the disadvantage that equipment investment is very large. In fact, high-refractive index resins and ultra-high-refractive index resins by urethane reaction and episulfide ring opening reaction have been put into practical use, but both require a large capital investment because they employ a thermal polymerization method. Is the current situation.

On the other hand, in the method of producing a lens using photopolymerization, since the polymerization time of photopolymerization is shorter than that of thermal polymerization, the production time of the lens can be shortened. Is an effective polymerization method. Even in the production of spectacle lenses, the polymerization time is about several minutes, so that the occupation time of the glass mold used is very short. Therefore, in the case of photopolymerization, the operation of manufacturing a lens can be repeated many times in the same time as when a single lens is manufactured by thermal polymerization. That is, even when mass-producing lenses, compared with thermal polymerization, there is no need for a large number of glass molds and large polymerization equipment, so that there is a feature that capital investment does not increase.

As the high refractive index material capable of photopolymerization, for example, a material obtained by preparing a prepolymerized product (prepolymer) of a thiol and a vinyl monomer (JP-A-4-578)
No. 31), a material using a novel sulfur compound (JP-A-8-183816), a material containing a polyfunctional thiomethacrylate and a cyclic polymerizable monomer as essential components (JP-A-1-26613), and the like. Has been proposed. These materials are high-refractive-index materials capable of performing not only thermal polymerization but also photopolymerization over time, and in fact, some of them achieve a refractive index of 1.60 or more.

[0008]

However, as a material for a spectacle lens, only a low-refractive-index lens made of a photocurable resin employing photopolymerization has been practically used. . That is, a material obtained by preparing a prepolymerized product of a thiol and a vinyl monomer disclosed in JP-A-4-57831 can obtain a material having a high refractive index, but requires a complicated prepolymerization step in photopolymerization. For this reason, there is a problem that a reduction in lens manufacturing time cannot be achieved. JP-A-8-183816 discloses a material using a novel sulfur compound, which can provide a material having a high refractive index. However, mass production technology has not been established because of the novel substance.
In addition, there are numerous problems, such as high cost, high specific gravity, and insufficient properties required for optical lenses such as impact resistance, dyeability, Abbe number, and transparency. A material having a polyfunctional thiomethacrylate and a cyclic polymerizable monomer as essential components disclosed in JP-A-1-26613 can provide a material having a high refractive index and excellent heat resistance. However, a combination of a polyfunctional thiomethacrylate and a cyclic polymerizable monomer can achieve a high refractive index, but when a substance having a cyclic structure is used as an essential component, the dispersion of light becomes large due to the birefringence. There is a problem that it is hard to be Abbe number. Furthermore, since a polyfunctional monomer has insufficient ductility if the cross-linking effect is large, there is a danger that the resulting resin is hard and brittle depending on its molecular structure and the monomer to be combined. That is, Japanese Patent Application Laid-Open No. 1-26613 does not examine optical dispersion characteristics, impact resistance, and dyeability, which are important characteristics in the field of spectacle lenses.

As described above, conventional high refractive index materials have problems such as difficulty in handling, moldability, and photopolymerization. In addition, a high refractive index material capable of photopolymerization has a problem that characteristics required for an optical lens such as handling, optical characteristics, impact resistance, and dyeing properties cannot be sufficiently obtained.

Therefore, an object of the present invention is to provide not only a high refractive index and a high Abbe number but also sufficient properties required for an optical lens such as impact resistance and dyeability, and not only thermal polymerization but also photopolymerization. It is an object of the present invention to provide an optical lens material that is also possible.

[0011]

Means for Solving the Problems As a result of intensive studies on polyfunctional thiomethacrylates, the present inventors have found that by combining a polyfunctional thiomethacrylate having a specific structure with a thiol having two or more functional groups, a high refractive index can be obtained. It has been discovered that while maintaining this, it is possible to simultaneously increase the Abbe number and impart ductility. As a result, it not only has a high refractive index and a high Abbe number, but also has sufficient properties required as an optical lens such as impact resistance and dyeing properties, and is capable of not only thermal polymerization but also photopolymerization, The development of a very excellent optical lens material was successful, and the present invention was completed here.

That is, according to the present invention, bis-2-methacryloylthioethyl sulfide represented by the following structural formula (1) is 20 to 80% by weight,
50% by weight, and monomers 0 to 7 copolymerizable therewith
A synthetic resin lens which is a copolymer obtained by copolymerizing a composition comprising 5% by weight and has a refractive index of 1.58 or more and an Abbe number of 35 or more.

CH ₂ CC (CH ₃ ) CO—S—CH ₂ CH ₂ —S—CH ₂ CH ₂ —S—COC (CH ₃ ) = CH ₂ Structural Formula (1) Screw-2 represented by the formula (1)
20-80% by weight of methacryloylthioethyl sulfide, 5-50% by weight of difunctional or higher thiol, and
A method for producing a synthetic resin lens having a refractive index of 1.58 or more and an Abbe number of 35 or more, comprising photopolymerizing a composition comprising 0 to 75% by weight of a monomer copolymerizable therewith. .

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The synthetic resin lens of the present invention contains bis-2-methacryloylthioethyl sulfide represented by the structural formula (1) in an amount of 20 to 80% by weight and a bifunctional or higher thiol in an amount of 5 to 50%. It is a copolymer obtained by copolymerizing a composition comprising 0 to 75% by weight of a monomer which can be copolymerized with the same by weight.

At this time, bis-2-methacryloylthioethyl sulfide is 20 to 80% by weight, preferably 30 to 80% by weight.
It contains 70% by weight. The reason is that if the content of bis-2-methacryloylthioethyl sulfide is less than 20% by weight, it is difficult to achieve the high refractive index characteristic of the present invention, and if it exceeds 80% by weight. This is because it becomes difficult to obtain sufficient impact resistance and dyeing properties as an optical lens. In addition, bifunctional or more thiol is 5-
It contains 50% by weight, preferably 15 to 40% by weight. The reason for this is that if the bifunctional or higher functional thiol is in an appropriate amount, appropriate ductility can be imparted, but the bifunctional or higher functional thiol is 5% by weight
If it is less than 50% by weight, or if it exceeds 50% by weight, it will be impossible to impart appropriate ductility, and as a result, it will be difficult to maintain sufficient impact resistance, dyeability, or heat resistance as an optical lens. .

As an example of the thiol having two or more functional groups, ethylene glycol bisthioglycolate (EG
TG), bifunctional sulfur compounds such as thiodietanthiol (DMDS), trifunctional sulfur compounds such as trimethylolpropane tristhioglycolate (TMTG) and trimethylolpropane tristhiopropionate (TMTP), pentaerythritol tetrakisthio Examples include, but are not limited to, tetrafunctional sulfur compounds such as glycolate (PETG) and pentaerythritol tetrakisthiopropionate (PETP).

The photocurable resin of the present invention may further comprise, if necessary, a monomer copolymerizable with these components in addition to the above components in order to impart various properties to the obtained resin. it can. However, if it exceeds 75% by weight, it becomes difficult to achieve a high refractive index and a high Abbe number, which are the characteristics of the present invention, so the range of 0 to 75% by weight is preferable.

The monomer at this time may be any as long as it can be copolymerized with the above-mentioned essential components. Examples include hydroxyethyl acrylate (HEA),
Monofunctional acrylic compounds such as hydroxypropyl acrylate (HPA), 2-phenylphenol polyethoxy acrylate (OPP), neopentyl glycol diacrylate (NPG), polyethylene glycol diacrylate (PEDA), tetramethylol methane triacrylate (TMM), Polyfunctional acrylic compounds such as 1,4-bisacryloylthiobenzene (BATB),
Monofunctional methacrylic compounds such as hydroxyethyl methacrylate (HEMA), hydroxypropyl methacrylate (HPMA), benzyl methacrylate (BZMA), 2-hydroxy-1,3-dimethacrylate (HD
P), polyfunctional methacrylic compounds such as 2,2-bis (4-methacryloxypolyethoxyphenyl) propane (BPE), trimethylolpropane trimethacrylate (TMPT), 1,4-bismethacryloylthiobenzene (BMTB), divinylbenzene (DVB), vinyl compounds such as styrene (St), α-methylstyrene dimer (MSD), allyl esters such as allyl benzoate (AKA) and diallyl phthalate (FDA), and the like, but are not limited thereto. Not something. Also,
The monomer at this time does not necessarily have to be one type, and two or more types can be combined. However, in order to maintain a high refractive index and a high Abbe number, which is a feature of the present invention, a monomer having a cyclic structure having a large birefringence and easily reducing the Abbe number is not preferred. . Further, in order to maintain the properties required for an optical lens such as impact resistance and dyeing properties, monofunctional monomers that significantly lower the mechanical strength are not so preferable. In other words, a monomer having a non-cyclic structure and a bifunctional or more functional group is more preferable. When a cyclic structure or a monofunctional monomer is employed, attention should be paid to the amount of the monomer.

The synthetic resin lens of the present invention can be obtained by subjecting the composition obtained as described above to radical polymerization, and by appropriately combining the ratios of the above-mentioned components, the viscosity of the composition can be sufficiently increased. By lowering it, it is possible to make the fluidity sufficiently high. Therefore, for example, it can be performed collectively in a casting container designed according to a use such as a plate shape, a lens shape, and a cylindrical shape, and can be manufactured easily and at low cost.

As the method of radical polymerization, a conventionally known method can be employed, such as a method of photopolymerization by irradiation with ultraviolet light in the presence of a photosensitizer,
Examples thereof include a method of performing heat polymerization in the presence of a radical polymerization initiator, and a method of performing polymerization by electron beam irradiation. In the present invention, the polymerization method is not particularly limited, but the method of photopolymerization by irradiation with ultraviolet rays is most preferable in consideration of the polymerization time, capital investment, and the like.

The method of photopolymerization by irradiation with ultraviolet light in the presence of a photosensitizer is relatively simple in equipment and handling, the curing speed is very fast, and the polymerization time can be shortened. Therefore, it is a very excellent polymerization method in which a large number of polymers can be obtained in a short time, and a polymer can be obtained at low cost and high efficiency. Examples of the photosensitizer that can be used at this time include α-hydroxyisobutylphenone, benzoin,
Benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2-hydroxy-2-benzoylpropane, benzyl dimethyl ketal, thioxane, 2-chlorothioxanthone, azobisisobutyronitrile, and the like. It is not limited.

The method of heating and polymerizing in the presence of a radical polymerization initiator is the most general method, and is simple in equipment and handling, but has a disadvantage that the curing rate is low. Examples of the radical polymerization initiator that can be used at this time include peroxides such as benzoyl peroxide and di-t-butyl peroxide, 2-2'azobisisobutyronitrile,
-2'azobis- (2,4-dimethylvaleronitrile)
And the like, but are not limited thereto.

The method of polymerizing by electron beam irradiation not only has a high curing rate, but also allows polymerization even in the absence of a catalyst or a photosensitizer, so that the contamination of the copolymer with impurities can be reduced. However, there is a disadvantage that the device is very expensive.

Further, the composition at this time may contain a coloring agent, a heat stabilizer and other auxiliary materials as necessary. Further, a hard coat agent, an anti-reflection coat, or another surface coat can be applied to the surface of the obtained copolymer.

The photocurable resin of the present invention is characterized in that it is a copolymer obtained as described above. Therefore, in addition to the cast polymerization method, a plate material or other copolymer can be obtained. It is also possible to manufacture by a method of shaving afterwards.

[0026]

The present invention will be described in more detail with reference to the following examples.
The present invention is not limited to these. In addition, the evaluation methods of the obtained various physical properties are as follows.

Refractive index A test piece of 10 mm × 20 mm × 3 mm was prepared, and the refractive index at room temperature (20 ° C.) was measured using “DR-M2” manufactured by Atago, using α-promonaphthaline as a contact liquid. did.

Abbe Number The Abbe number was measured by the same measuring device and measuring method as used for the above-mentioned refractive index measurement.

A test piece having a specific gravity of 10 mm × 20 mm × 3 mm was prepared, and the specific gravity was measured using “SGM-6” manufactured by METTLER TOLEDO.

Impact Resistance Ten test samples having a diameter of 78 mm, a radius of curvature of 0.1 m, and a center thickness of 2 mm were prepared, and steel balls weighing 16.2 g (diameter 10/16 inch) were weighed 1.27 m. It was dropped from the height, and according to the standard of FDA falling ball impact strength, 10 pieces that did not crack were evaluated as good, and one that was cracked was evaluated as poor.

Stainability A dye solution is prepared by mixing 1 g each of Seiko Plux Brown manufactured by Hattori Seiko Co., Ltd. and 1000 g of pure water, and the obtained lens is immersed in the dye solution at 92 ° C. for 10 minutes. Dyeing was performed by using the ultraviolet and visible spectrophotometer “UV-2200” manufactured by Shimadzu Corporation, and the total light transmittance was measured. did.

Transparency A flat plate having a center thickness of 2.0 mm was prepared and “H” manufactured by Suga Test Instruments Co., Ltd.
The haze was measured using "GM-2DP" and the haze was 0.3
The following were rated good, and those exceeding 0.3 were rated poor.

Example 1 Bis-2-methacryloylthioethyl sulfide (TE
S) 50 g, pentaerythritol tetrakisthiopropionate (PETP) 20 g, and hydroxydimethacrylate (HDP) 30 g were measured in a 200 ml beaker, and 1000 ppm of a photopolymerization initiator, IRGACURE 184 (Nippon Ciba Geigy Co., Ltd.), was added, followed by sufficient stirring. After that, the mixture was poured into a casting mold composed of two glass plates and a gasket, and irradiated with an irradiation dose of 800 m using an ultraviolet irradiation device.
Photopolymerization was performed under the conditions of W / cm ² , irradiation distance of 50 cm, and irradiation time of 10 min. Thereafter, the copolymer was taken out of the casting mold to obtain a finished product.

The obtained copolymer has physical properties as shown in Table 1, and has a refractive index of 1.58 or more, an Abbe number of 35 or more,
A molded article having a specific gravity of 1.40 or less and excellent impact resistance, dyeing properties, and transparency was obtained.

Examples 2-3 The polymerization compositions were mixed at composition ratios as shown in Examples 2-3 in Table 1 and a photopolymerization initiator, IRGACURE 184, was mixed.
After 1000 ppm (Nippon Ciba Geigy Co., Ltd.) was added and sufficiently stirred, the mixture was poured into a casting mold composed of two glass plates and a gasket, and the irradiation dose was 800 mW / cm ² and irradiation distance by an ultraviolet irradiation device. 50 cm, irradiation time 1
Photopolymerization was performed under the condition of 0 min. Thereafter, the copolymer was taken out of the casting mold to obtain a finished product.

The obtained copolymer had physical properties as shown in Table 1, and had a refractive index of 1.58 or more, an Abbe number of 35 or more, and
A molded article having a specific gravity of 1.40 or less and excellent impact resistance, dyeing properties, and transparency was obtained.

Examples 4 to 6 The polymerization compositions were mixed at the composition ratios shown in Examples 4 to 6 in Table 1, and 2,2-azobis (2,4-dimethylvaleronitrile) as a radical polymerization initiator was mixed. ) Is added 0.1 g,
The mixture was poured into a casting mold composed of two glass plates and a gasket to perform thermal polymerization. Thermal polymerization is performed in a hot air circulation furnace for 4 hours.
The temperature was gradually raised from 5 ° C to 100 ° C over 10 hours,
After maintaining at 00 ° C for 2 hours, it was gradually cooled to 65 ° C. Thereafter, the copolymer was taken out of the casting mold to obtain a finished product.

The obtained copolymers were able to obtain physical properties as shown in Table 1. In Examples 4 to 6,
All had a refractive index of 1.58 or more, an Abbe number of 35 or more and a specific gravity of 1.40 or less, and molded articles having good impact resistance, dyeing properties, and transparency were obtained.

Comparative Example 1 Bis-2-methacryloylthioethyl sulfide was 20
Under the condition of less than% by weight, a composition was prepared at a ratio as in Comparative Example 1 in Table 1, and the same thermal polymerization as in the above example was performed. The resulting resin has a refractive index of 1.58
And a problem was confirmed in the refractive index.

Comparative Example 2 Bis-2-methacryloylthioethyl sulfide was 80
The composition was prepared at a ratio as shown in Comparative Example 2 in Table 1 under conditions exceeding the weight%, and photopolymerization was carried out in the same manner as in the above Examples. The resulting resin was found to have problems with impact resistance and dyeability.

Comparative Example 3 A composition was prepared at a ratio as shown in Comparative Example 3 in Table 1 under the condition that the amount of the bifunctional or higher thiol exceeds 50% by weight.
The same thermal polymerization as in the above example was performed. The resulting resin was insufficient in mechanical strength as it was soft even at room temperature, and it was impossible to measure the refractive index and other physical properties.

COMPARATIVE EXAMPLE 4 As a comparative example, bis-2-methacryloylthioethyl sulfide which is a main component of the present invention was less than 25% by weight in total of difunctional or higher thiol, and 75% of a monomer copolymerizable therewith. The composition was prepared at a ratio as shown in Comparative Example 4 of Table 1 under conditions exceeding the weight%, and photopolymerization was carried out in the same manner as in the above Examples. The resin obtained as a result had a refractive index of less than 1.58, and not only problems with the refractive index were confirmed, but also problems with the impact resistance and the dyeing property were confirmed.

Comparative Example 5 A composition was prepared at a ratio as shown in Comparative Example 5 in Table 1 under the condition that bifunctional or higher functional thiol was less than 5% by weight, and the same thermal polymerization as in the above example was performed. The resin obtained as a result had a refractive index of less than 1.58, and not only problems with the refractive index were confirmed, but also problems with the impact resistance and the dyeing property were confirmed.

COMPARATIVE EXAMPLE 6 As an example using only bis-2-methacryloylthioethyl sulfide and a polymerizable monomer having a cyclic structure, a composition was prepared at a ratio as shown in Comparative Example 6 in Table 1. The same photopolymerization as in the example was performed. The resulting resin was found to have problems with impact resistance and dyeability.

[0045]

[Table 1]

[0046]

Industrial Applicability The present invention provides a very excellent synthetic resin having not only a high refractive index and a high Abbe number, but also has sufficient properties required for an optical lens such as impact resistance and dyeability. The lens can be easily mass-produced in a short time by a simplified process such as a photopolymerization method.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) // B29K 81:00 B29K 81:00 B29L 11:00 B29L 11:00 (72) Inventor Kenji Uno Tokyo 2-40-2 Hongo, Bunkyo-ku F-term in the seed company (reference) 4F204 AA34 AA44 AH74 EA03 EB01 EK18 EK24 4J011 GA05 GB07 GB08 QA03 QA07 QA08 QA09 QA12 QA18 QA19 QA20 QA24 QA33 QA34 QA10 TAA QA10 4J100 AB02Q AB07Q AB16Q AG15Q AG70Q AK47P AK47Q AL08Q AL09Q AL62Q AL63Q AL66Q AL67Q BA03Q BA08Q BC43Q CA01 CA04 JA33

Claims (4)

[Claims] 1. Bis-2 represented by the following structural formula (1)
20-80% by weight of methacryloylthioethyl sulfide, 5-50% by weight of difunctional or higher thiol, and
A copolymer obtained by copolymerizing a composition comprising 0 to 75% by weight of a monomer copolymerizable therewith, having a refractive index of 1.58 or more and an Abbe number of 35 or more. A synthetic resin lens. CH ₂ = C (CH ₃ ) CO-S-CH ₂ CH ₂ -S-CH ₂ CH ₂ -S-COC (CH ₃ ) = CH ₂ Structural formula (1) 2. The synthetic resin lens according to claim 1, which is a copolymer obtained by photopolymerizing the composition. 3. Bis-2- represented by the structural formula (1)
Photopolymerizing a composition comprising 20 to 80% by weight of methacryloylthioethyl sulfide, 5 to 50% by weight of difunctional or higher thiol, and 0 to 75% by weight of a monomer copolymerizable therewith. A method for producing a synthetic resin lens having a refractive index of 1.58 or more and an Abbe number of 35 or more. 4. The method for producing a synthetic resin lens according to claim 3, wherein the composition is photopolymerized in a casting mold.