JPH03215801A - Plastic lens material - Google Patents

Abstract

PURPOSE:To provide the plastic lens material which has a high refractive index and Abbe number and has high strength and high heat resistance by using a polymer formed by polymerizing monomers introduced with alicyclic sulfide as a residual ester group. CONSTITUTION:The plastic lens material consists of the polymer contg. the compd. expressed by general formula [I] as its essential monomer component. The monomer expressed by the general formula [I] includes 4-(meth) acryloxymethyl-1, 3-dithiorane and 2-(meth)acryloxymetnyl-1, 4-diathine. The preferable ratio of the monomer expressed by the general formula [I] is 50 to 100wt.%. Namely, the effect of enhancing the refractive index, strength and heat resistance is low if the ratio is below 50wt.%. The monomer used as the copolymer component is exemplified by a monofunctional monomer, monofunctional monomer, macromonomer, etc. The homopolymers having >=1.48 refractive index are preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to plastic lens materials. The plastic lens material of the present invention has a high refractive index, low dispersion, and excellent optical properties, and is particularly preferably used for eyeglass lenses and camera lenses.

[Prior Art] Plastic lenses have been used in eyeglass lenses, camera lenses, and optical elements in recent years because they are lighter, more difficult to break, and easier to dye than glass lenses. Polyethylene glycol bisallyl carbonate (CR-39) is generally used as a plastic lens material. The refractive index (no) of this material is 1.50, so in order to obtain the same optical properties as a glass lens for eyeglasses (nD = 1.52), the thickness of the lens must be increased. did not become.

Therefore, if this was used as a lens for spectacles, the thickness of the lens would increase, resulting in poor aesthetics, which was not preferable. In particular, in the case of a concave lens, the thickness around the lens becomes thick, causing birefringence and chromatic aberration, which is not desirable.

Therefore, there is a demand for a plastic lens material with a high refractive index that can reduce the thickness of the lens while taking advantage of the characteristics of a plastic lens with light specific gravity.

As a plastic lens material that provides a high refractive index, Japanese Patent Application Laid-Open No. 62-276501 discloses a material that has a refractive index of 1.63 or more by introducing a naphthalene ring. Also, in Japanese Patent Application Laid-Open No. 61-88201,
A material has been disclosed that has a refractive index of 1.60 or more by introducing brominated biphenyl into a carbamate bond. Further, JP-A-64-26622 discloses a material whose refractive index is 1.58 or more by introducing an S-carbamate bond.

Further, JP-A-62-34101 discloses a material having a refractive index of 1.60 or more by introducing a brominated bisphenol A skeleton.

[Problems to be Solved by the Invention] However, the plastic lens material described in JP-A-62-276501 is brittle and has poor impact resistance, so reducing the thickness of the lens reduces the mechanical strength of the lens. The disadvantage is that it is not satisfied.

Also, the above-mentioned Japanese Patent Application Laid-Open No. 61-88201. Although the plastic lens materials described in JP-A-64-26622 and the above-mentioned JP-A-64-26622 solve this problem of impact resistance, polymerization becomes non-uniform during the production of plastic lenses, and striae are likely to occur. Furthermore, there is a drawback that optical distortion occurs due to the striae. In particular, the plastic lens material described in JP-A-61-88201 has the drawback of poor weather resistance and easy yellowing when used for a long period of time. Furthermore, the plastic lens material described in JP-A No. 64-26622 has poor heat resistance, and when an anti-reflection hard coat layer is applied to it, cracks tend to occur in the hard coat layer as stress on the surface is alleviated due to heat. There is a drawback. Furthermore, the plastic lens material described in the above-mentioned Japanese Patent Application Laid-Open No. 62-34101 also has the drawback of poor weather resistance and yellowing after long-term use.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a plastic lens material which overcomes the drawbacks of the prior art plastic lens materials mentioned above.

[Means for Solving the Problems] The present invention has been made to achieve the above objects, and the plastic lens material of the present invention has the following general formula [
It is characterized by consisting of a polymer containing the compound shown in [1] as an essential monomer component.

(In the formula, n is 1 or 2, and R represents a hydrogen atom or a methyl group.) That is, the above monomer providing the plastic lens material of the present invention has an alicyclic sulfide introduced as an ester residue. It is a feature. This alicyclic sulfide contains two sulfur atoms in a 5- or 6-membered ring and has a cyclic skeleton, so it has a very high refractive index and Abpe's number. In addition, the polymer made by polymerizing this monomer not only has a high refractive index and Abpe number, but also
5 It has high strength and high heat resistance because it has a rigid alicyclic sulfide in its side chain.

Next, the reason why n is limited to 1 or 2 in the compound of general formula [1] will be described. If n is 0, a disulfide bond will be formed and it will be chemically unstable, which is not preferable. Moreover, when n becomes 3 or more, the refractive index decreases. Furthermore, it is undesirable because the mechanical strength and heat resistance of the polymer decrease. Therefore,
n is limited to 1 or 2.

The monomer represented by the general formula [1] is 4-(meth)
Examples include acryloxymethyl-1,3-dithiolane and 2-(meth)acrylic dimethyl-1,4-dithiane.

The plastic lens material of the present invention is basically composed of a polymer obtained by polymerizing one or more compounds represented by the general formula [1], but if necessary, other radically polymerizable monomers may be used. It may be composed of a polymer obtained by using as a copolymerization component.

The preferred amount 6 of the monomer represented by general formula [1] is 50-100% by weight. The reason is that 50% by weight
This is because if it is less than that, the effect of increasing refractive index, strength, heat resistance, etc. will be small. Monomers used as copolymerization components include monofunctional monomers, monofunctional monomers, macromonomers, etc., and their homopolymers have a refractive index of 1.4.
A value of 8 or more is desirable. Specifically, 2,3-dibromopyr (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, chlorophenyl (meth)acrylate, tribromophenyl (meth)acryly}, 3- (meth)acrylate ) Acryloyloxymethylthiophine, 2-tricyclo[5,2,1
, 02.6-3.4-dibromodecylthioethyl (meth)acrylate, ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, 2.2-bis[4-(meth)acryloxyphenyl ] Propane, 2,2-bis[4-(meth)acryloxyphenylcosulfone, methylthio(meth)acrylate, pendylthio(meth)acrylate 1-, 2.
Examples include 2-bis(4-allyloxy-3.5 dibromophenyl)propane, styrene, chlorostyrene, dibromostyrene, divinylbenzene, epoxy (meth)acrylate, polyester (meth)acrylate, urethane (meth)acrylate, and the like.

A lens made of the plastic lens material of the present invention is produced by adding 0.01 parts by weight to 100 parts by weight of a monomer composition in which one or more monomers represented by general formula [1] are mixed with other radically polymerizable monomers as necessary. It is obtained by adding ~10 parts by weight of a polymerization initiator and uniformly dissolving it, then pouring it into a glass mold of a predetermined shape, and polymerizing by heating or irradiating with ultraviolet rays. There are no particular limitations on the polymerization initiator as long as it generates radicals upon heating or UV irradiation. When polymerizing by heating,
Azobisisobutyronitrile, azobisdimethylbaretnitrile, benzoyl peroxide, etc. are used, and the polymerization temperature is preferably 0 to 150°C, and the polymerization time is preferably 0.5 to 72 hours. In addition, when polymerizing by ultraviolet irradiation, 2,
2'-diethoxyacetophenone, 2-hydroxy-
2-methyl-1-phenylpropan-1-one, penzophenone, benzyl dimethyl ketal, etc. are used, and the irradiation intensity is 0.1 to 100 mW/cJ and the irradiation time is 1.
Preferably from minutes to 10 hours.

The plastic lens material of the present invention may also contain known additives, such as ultraviolet absorbers, antioxidants, drip-proofing agents, and colorants.

[Examples] Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples.

(Evaluation of physical properties) Physical properties of the polymers obtained in Examples and Comparative Examples were evaluated as follows.

Refractive index (nD) and Abpe number (νp) Measured at 20° C. using an Atago Appe refractometer 3T.

exterior 9 Observation was made with the naked eye.

The lens was set in a weather meter equipped with a weather-resistant sunshine carbon arc lamp, and after 200 hours, the lens was taken out and the hue was compared with the lens before the test. The evaluation criteria were: no change (○), slight yellowing (△), and yellowing (×).

1 using a 2mmφ pin using a heat-resistant Rigaku TMA device.
TMA measurement was performed under a load of 0 gf, and evaluation was made based on the peak temperature of the obtained chart.

Visual observation was performed using the optical distortion Schlieren method. Those with no distortion were rated 0, and those with distortion were rated ×.

Impact Resistance Lenses with a center thickness of 2 mm were tested according to FDA standards. Those that passed were marked as 0 and those that did not pass were marked as ×.

(Example 1) 10 2-methacryloxymethyl-1,4-dithiane (abbreviated as TMA in Table 1: n = 2, R in general formula [1]
= methyl group) and 0.5 parts by weight of azobisdimethyl nitrile were poured into a lens mold consisting of an upper mold, a lower mold, and a gasket.
℃ for 10 hours, then 60℃ for 5 hours, then 120℃
The mixture was heated for 3 hours to polymerize and obtain a plastic lens. Table 1 shows the physical properties of the obtained plastic lens.

From Table 1, the plastic lens of Example 1 is colorless and transparent, has a high refractive index of 1.59, has a high Abbe number of 43, and has good weather resistance, impact resistance, and heat resistance (94°C). It was excellent and had no optical distortion.

(Examples 2 to 7) Example 1 except that the monomer composition shown in Table 1 was used.
A plastic lens was obtained by performing the same operation as above. The physical properties of these plastic lenses are shown in Table 1 together with the physical properties of the plastic lens of Example 1. From Table 1,
The P11 plastic lenses of Examples 2 to 7 are colorless and transparent, and have a refractive index of 1.56.
~1.62, and the Abpe's number was as high as 37 to 52, and was excellent in weather resistance, impact resistance, and heat resistance (94 to 120°C), and had no optical distortion.

(Comparative Example 1) 43.5 parts by weight of m-xylylene diisocyanate, 56.5 parts by weight of pentaerythritol tetrakis (mercaptopionate), 0.0 parts by weight of dibutyltin dilauret
A homogeneous mixture of 5 parts by weight was poured into a lens mold, and 50 parts by weight was poured into a lens mold.
℃ for 10 hours, then 60℃ for 5 hours, then 120℃
The mixture was heated for 3 hours to polymerize and obtain a plastic lens. Table 1 shows the physical properties of the obtained plastic lens.

From Table 1, although the plastic lens of Comparative Example 1 was colorless and transparent and had excellent impact resistance, its heat resistance was low at 86° C. and optical distortion was observed.

(Comparative Example 2.3) Example 1 except that the monomer composition shown in Table 1 was used.
The same operation as above was performed to obtain 12 plastic lenses. The physical properties of these plastic lenses are shown in Table 1 together with the physical properties of the plastic lens of Comparative Example 1.

Table 1 shows that the plastic lens of Comparative Example 2 had no optical distortion and had excellent impact resistance, but was pale yellow in color and had poor weather resistance. Furthermore, although the plastic lens of Comparative Example 3 was colorless and transparent and had no optical distortion, it was inferior in weather resistance and impact resistance.

(Left below) 13 (Abbreviations in Table 1) O (In general formula [1], n=2, R=CH3) C (In general formula [1, n=2, R=H) 15 VN: Vinyl Naphthalene TMPTMA: } Limethylolpropane trimethacrylate BzMA: Benzyl methacrylate EDMA: Ethylene glycol dimethacrylate DMM
CD: dimethacryloxymethyltricyclo[5,2,1
．． 02.6 Codecane VT: Vinylthiophene DVB: Divinylbenzene B r2 PMA: 2,3-dibromopyrmethacrylate B r3 PM
A: 2,4.6-tribromophenyl methacrylate ADVN: azobisdimethylvaleronitrile DBTDL
: dibutyltin dilaurate LPO : lauroyl peroxide [Effects of the invention] As described above, the plastic lens material of the present invention is colorless and transparent, has a high refractive index, low dispersion, and has impact resistance,
It has excellent weather resistance, heat resistance, and no optical distortion. In particular, when used as a concave lens for eyeglasses, the peripheral thickness of the lens can be made thinner, and there are advantages in that there is no birefringence or chromatic aberration.

Claims (1)

[Claims] (1) A plastic lens material comprising a polymer containing a compound represented by the following general formula [1] as an essential monomer component. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [1] (In the formula, n is 1 or 2, and R represents a hydrogen atom or a methyl group)