JPH02213801A - Molded plastic lens - Google Patents

Abstract

PURPOSE:To reduce the rate of shrinkage by hardening to <=7% by polymerizing a liq. mixture of a urethane (meth)acrylate oligomer having a specified compsn. with an unsatd. (meth)acrylate compd. having a specified compsn. in a casting mold. CONSTITUTION:A liq. mixture of 10-50wt.% bi-, ter- or quaterfunctional urethane (meth)acrylate oligomer with 40-90wt.% uni- or bifunctional unsatd. (meth) acrylate compd. having alicyclic alkyl or a heterocyclic structure and 0-30wt.% ter- or higher functional unsatd. (meth)acrylate compd. is polymerized in a casting mold. A molded plastic lens can be obtd. at <=7% rate of shrinkage by hardening. The oligomer is prepd. by allowing aliphat. or alicyclic polyol and/or aliphat. or alicyclic polyether polyol to react with alicyclic polyisocyanate and hydroxy(meth)acrylate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to plastic molded lenses used in optical products such as eyeglasses, still cameras, video cameras, microscopes, telescopes, and optical pickups, particularly those having a refractive index of 1. 48～1,
It relates to a plastic molded lens with a number of 52 and 60 to 44.

[Conventional technology]

To obtain desired optical performance, optical designers design optical products by combining various lenses. Therefore,
Optical designers require not only lenses with different curvatures, but also lenses with different refractive indexes and Abbe numbers (inverse dispersion ratios) of materials. Among them, the refractive index of the material is 1.48 to 1.
Lenses with a size of 52 and an Atsube number of 60 to 44 are in high demand.

By the way, lenses have conventionally been generally made of glass. However, in addition to the drawbacks of being heavy and easily broken, glass lenses require many steps to manufacture, including producing a lens blank by press molding, grinding, and polishing. - Since the polishing process takes a lot of time, the manufacturing cost of the lens is high and mass production is not possible.

Therefore, a plastic molded lens was developed that could transfer the shape of a lens by making just one mold. There are two main types of plastic molded lenses.

The first type is a thermoplastic resin in which the plastic material is already polymerized before molding, and this is melted and softened to form a lens by press molding, injection molding, or the like. However, this type has the drawbacks of easy optical distortion and poor shape accuracy.

The second type, on the other hand, does not have such drawbacks.

In the second type, the plastic material is not yet polymerized before molding, and is a monomer or oligomer (a low polymer that can be further polymerized to become a polymer), and this is poured into the mold. and polymerize and polymerize in the mold (
This is called cast polymerization, in which polymerization and molding are performed simultaneously) to obtain lenses.

The second type of lens, whose material has a refractive index of 1.48 to 1.52 and an Atsube number of 60 to 44, has the following structural formula 0.
Formula %): Lens obtained by cast polymerization (refractive index of material 1.50
, Atsbe number 57.9) have been frequently used.

[Problem to be solved by the invention]

However, this lens has a curing shrinkage rate of 1 after polymerization.
There was a problem in that it was as high as 3 to 14%, and therefore unsuitable for lenses that required cavity shape accuracy.

Therefore, a first object of the present invention is to provide a plastic molded lens that has a low curing shrinkage rate of 7% or less and therefore has high shape accuracy.

In addition, according to the research of the present inventor, as a lens,
■ High transmittance (wavelength λ - 360 nm, thickness t = 3
(85% or more at 0μm), ■High weather resistance, ■High heat resistance, ■High hot water resistance, ■High solvent resistance, ■Hardness of H or higher on a pencil hardness scale, ■ Good releasability from molds, especially molds, without the addition or coating of mold release agents (mold release agents are used to improve the transmittance and weather resistance of molded lenses, as well as adhesion to surface coating layers such as inorganic anti-reflection coatings). A second object of the present invention is to provide a plastic molded lens that satisfies these demands.

[Means to solve the problem]

Therefore, the present invention provides: (a) an aliphatic (including cycloaliphatic) polyol and/or an aliphatic (including cycloaliphatic) polyether polyol, an alicyclic polyisocyanate, and a hydroxy (meth)acrylate. 210 to 50% by weight of di- to tetrafunctional urethane (meth)acrylate oligomer obtained by reaction, preferably 20
~45% by weight (b) Mono- or difunctional unsaturated (meth)acrylate compound having an alicyclic alkyl or heteroartic ring structure: 40-90% by weight, preferably 50-80% by weight, and (c) trifunctional A mixture solution containing the above unsaturated (meth)acrylate compound - 0 to 30% by weight, preferably 10 to 25% by weight, is polymerized in a mold, and the flexural index is 1.48.
~1.52 and an Abe number of 60 to 44 is provided.

[Effect]

The (a) urethane (meth)acrylate oligomer used in the present invention consists of: ■ aliphatic (including cycloaliphatic) polyol and/or aliphatic (including cycloaliphatic) polyether polyol; It is obtained by reacting isocyanate with hydroxy (meth)acrylate, and has an average functionality number (number of ethylenically unsaturated double bonds) of 2 to 4 per molecule, and no longer has an active NGO group. , preferably has a number average molecular weight of about 750 to 9,000 and is liquid or solid at room temperature.

(a) To synthesize the urethane (meth)acrylate oligomer, first, ■ polyol and ■ isocyanate are mixed with N
The ratio of CO groups to 10H groups is 1.2 to 2.0, preferably 1.5
By reacting at a ratio of ~2.0, a prepolymer having an NGO group at the end is obtained, and then this prepolymer and (meth)acrylate are combined with NCO group 10H.
The reaction is carried out in such a proportion that the ratio of the groups is 1.0 to 1.1, preferably 1.0 to 1.05.

This yields (a) oligomer. In the second step, if the ratio of NCO groups to 10H groups is less than 1.0, unreacted NGO groups will remain in the target product, which is undesirable. ■(meta)
This is not preferred because acrylate remains.

Aliphatic (including cycloaliphatic) polyols used as starting materials include, for example, glycerin, trimethylolpropane, pentaerythritol, ethylene glycol, propylene glycol, neopentyl glycol,
Hydrogenated bisphenol A, 1,3-butanediol, 1
, 4-butanediol, 1,5bentanediol, 1,
One or more types of 6-hexanediol, tricyclodecane dimethylol, etc. are used.

In addition, ■Aliphatic (including alicyclic) polyether polyols include, for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol,
One or more of hydrogenated bisphenol A ethylene oxide adducts, hydrogenated bisphenol A propylene oxide adducts, tricyclodecane dimethylol ethylene oxide adducts, tricyclodecane dimethylol ethylene oxide adducts, etc. are used.

These ■Aliphatic (including cycloaliphatic) polyols and ■Aliphatic (including cycloaliphatic) polyether polyols may be used alone or in combination. .

(2) As the alicyclic polyisocyanate, one or more of, for example, isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated 4,4-diphenylmethane diisocyanate, etc. can be used.

■Hydroxy (meth)acrylates include, for example,
2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, polyethylene glycol mono (meth)acrylate, polypropylene glycol mono (meth)acrylate, glycerin mono (meth)acrylate, glycerin di(meth)acrylate, 2- One or more of ε-caprolactone adducts of hydroxyethyl (meth)acrylate and ε-caprolactone adducts of 2-hydroxypropyl (meth)acrylate are used.

In addition, in this specification, the description 1(meth)-m----J refers to both compounds read including meta and compounds read without including meta (including single use and mixed use). means.

(b) Mono- to difunctional unsaturated (meth)acrylate compounds having an alicyclic alkyl or heterocyclic structure include, for example, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, ethylene oxide-modified Cyclopentanyl (meth)acrylate, propylene oxide modified dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, ethylene oxide modified dicyclopentenyl (meth)acrylate, propylene oxide modified dicyclopentenyl (meth)acrylate, Isobornyl (meth)acrylate, methoxylated cyclododecatriene (meth)acrylate, (meth)acryloylmorpholine, tetrahydrofurfuryl (meth)acrylate, ε-caprolactone modified tetrahydrofurfuryl (meth)acrylate,
Methoxylated cyclohexyl di(meth)acrylate, di(meth)acrylated isocyanurate, hydroxypihalyl aldehyde modified trimethylolpropane di(meth)
Acrylate, hydrogenated bisphenol A di(meth)acrylate, ethylene oxide modified hydrogenated bisphenol A di(meth)acrylate, propylene oxide modified hydrogenated bisphenol A di(meth)acrylate, ε
- Caprolactone-modified hydrogenated bisphenol A di(meth)acrylate, tricyclodecane dimethylol di(meth)acrylate, ethylene oxide-modified tricyclodecane dimethylol di(meth)acrylate, propylene oxide-modified tricyclodecane dimethylol di(meth)acrylate One or more types of acrylate, ε-caprolactone-modified tricyclodecane dimethylol di(meth)acrylate, etc. are used.

(c) Trimethylolpropane tri(meth)acrylate, glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, di- Pentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, propionic acid modified dipentaerythritol penta(meth)acrylate
One or more types of acrylate, ε-caprolactone-modified dipentaerythritol hexa(meth)acrylate, etc. are used.

In the present invention, a liquid mixture is prepared by mixing the above components (a), (b), and optionally (c) at a predetermined ratio.

The mixed liquid contains a polymerization initiator, ultraviolet absorber, antioxidant,
Stabilizers, colorants, polymerization inhibitors, etc. may be added in advance.

In order to polymerize the mixed liquid, the mixed liquid may be heated. In addition to or in place of heating, radiation such as ultraviolet rays, gamma rays, X-rays, and electron beams may be irradiated. When polymerizing by irradiating ultraviolet rays, it is preferable to add a photopolymerization initiator to the mixed solution in advance.

As the initiator, for example, common radical initiators such as benzoyl peroxide, diisopropyl peroxydicarbonate I., azobisisobutyronitrile, etc. can be used.

Examples of photopolymerization initiators include benzophenone, hydroxybenzophenone methanesulfonate ester,
- benzophenone derivatives such as benzoyl-methylbenzoate, p-chlorobenzophenone, p-dimethylaminobenzophenone, benzoin, benzoin allyl ether, benzoin alkyl ether (alkyl groups are, for example, methyl, ethyl, isopropyl, isobutyl, etc.),
Acetophenones such as acetophenone, jetoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, benzyl dimethyl ketal, 2-hydroxy-methylpropiophenone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropiophenone, etc. Examples include derivatives and oximes.

To polymerize the mixed solution, it is placed in a mold and polymerized as described above. Since it is necessary to take out the polymerized and molded lens, a split mold consisting of two inverted lens molds is used as the mold.

The mold may be a glass mold or a metal mold, but the metal mold is CN
It is preferable because it can be made more easily on a C lathe than glass. however,
When carrying out photopolymerization, it is necessary to use a transparent glass mold for at least one of the molds.

In some cases, a lens substrate (
For example, a spherical convex lens, a rough aspherical convex lens, a spherical concave lens, a flat lens) may be used to mold the lens on the substrate surface in situ. US patents issued in 19492,4
No. 64,738 discloses a technique in which a glass spherical lens is used as a substrate and an aspherical plastic is molded on the surface thereof on the spot to obtain a bonded aspherical lens made entirely of glass and plastic. In this case, the molded lens can be obtained in a state bonded to the substrate.
This is one advantage. However, since the adhesive force between the molded lens and the substrate is weak and the two are easily separated, it is preferable to treat the surface of the substrate with a silane coupling agent in advance.

Examples of the silane coupling agent include methyltrimethoxysilane, methyltriethoxysilane, dimethyljethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyl I-rimethoxysilane, aminomethyltrimethoxysilane, Examples include sidoxypropyltrimethoxysilane and glycidoxypropylmethyldimethoxysilane.

Further, in the lens of the present invention, the plastic surface on the side that comes into contact with air may be spherical, aspherical, or flat.

Hereinafter, the present invention will be specifically explained with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited thereto.

The number average molecular weight was measured using gel permeation chromatography using a calibration curve method using a polystyrene standard material.

[Synthesis Example 1 - Synthesis example of component (a)] 169.25 parts by weight of neopentyl glycol, 1750.0 parts by weight of polytetramethylene glycol (molecular weight 2000), and 1111.5 parts by weight of isophorone diisocyanate were placed in a reaction vessel. The reaction was carried out while maintaining the temperature at 75 to 80°C. The reaction was continued until completion as indicated by 6.93% free NGO groups.

Then 2-hydroxyethyl acrylate 592.2
Part by weight, hydroquinone monomethyl ether 1.81
Additional parts by weight were added and the reaction was further continued at a temperature of 75-80°C.

The reaction was continued until completion as indicated by less than 0.3% free NGO groups.

In this way, a slightly yellow liquid urethane acrylate oligomer (viscosity: 200 voids/60° C.) was obtained.

This oligomer had an average number of functional groups per molecule of 2 (that is, bifunctional) and a number average molecular weight of 1,440.

Hereinafter, this will be abbreviated as UA-1.

[Synthesis Example 2 - Synthesis example of other component (a)] 196.29 parts by weight of tricyclodecane dimethylol and 1-444.57 parts by weight of isophorone diisocyanate were charged into a reaction vessel, and synthesis was carried out. As in Example 1, the free NGO group is 13.1
The reaction was carried out until %.

Then 2-hydroxyethyl acrylate 236.8
8 parts by weight, hydroquinone monomethyl ether 0.44
Parts by weight and dicyclopentanyl acrylate 877.7
4 parts by weight was added, and the following procedure was carried out in the same manner as in Synthesis Example 1 to obtain free NGO.
The reaction was continued until the group concentration was 0.15% or less.

In this way, a colorless and transparent liquid (viscosity 160voices/25℃)
was gotten. This liquid contains 50% by weight of urethane acrylate oligomer and 50% by weight of dicyclopentanyl acrylate.
It was a mixture of % by weight. The average number of functionalities per molecule of the oligomer was 2 (that is, bifunctional), and the number average molecular weight was 873.

Below, this urethane acrylate oligomer is used as U8-2.
It is abbreviated as

[Synthesis Example 3 - Synthesis example of other component (a)] 196.29 parts by weight of tricyclodecane dimethylol, 524.70 parts by weight of dicyclohexylmethane diisocyanate, and 957 parts by weight of dicyclopentanyl acrylate .87 parts by weight was charged into a reaction vessel, and the free NGO was prepared in the same manner as in Synthesis Example 1.
The reaction was carried out until the group concentration was 5.00%.

Then 2-hydroxyethyl acrylate 236.8
8 parts by weight, hydroquinone monomethyl ether 0.48
Parts by weight were added, and the reaction was continued in the same manner as in Synthesis Example 1 until the free NGO group became 0.15% or less.

Thus, a colorless and transparent liquid (viscosity 370 poise/25℃)
was gotten. This liquid contains 50% by weight of urethane arallylate oligomer and 50% by weight of dicyclopentanyl acrylate.
It was a mixture of % by weight. The oligomer had an average number of functionalities per molecule of 2 (that is, bifunctional) and a number average molecular weight of 953. Hereinafter, this urethane acrylate oligomer will be abbreviated as IIA-3.

[Examples 1 to 3] (1) First, a glass lens substrate 1 and a mold 2 were prepared as split molds.

The lens substrate 1 has a diameter Φ=40II1m, a convex curvature R,
-80n+m, concave curvature Rz = 150mm, center thickness t
, = 9 mm, the type of glass is called C-10, and the refractive index is n, = 1.
495, Atsbe number ν4656.5.

The convex surface of the lens substrate 1 was previously treated with alcohol it of methacryloxypropyltrimethoxysilane.

The mold 2 is an iron mold whose approximate spherical surface is machined by a CNC lathe into a predetermined aspherical surface having a concave surface with a curvature R3=80 mm, and is finished with Ni plating.

(2) Place the mold 2 horizontally with the concave side facing up, and add 3 m of a mixed solution having the composition described in each example in Table 1 below to 1-hydroxycyclohexylphenyl ketone as a photopolymerization initiator. A slightly larger amount than the predetermined amount was added (see Figure 1).

Next, Lennon 2. The i-kari 1 was held horizontally with the convex side facing down, and gently placed on top of 3 m of the mixed liquid so as not to introduce air bubbles, and then pressed downward.

However, the gap between the mold 2 and the substrate 1 is 30 to 40 μm at the center.
The pushing of the substrate 1 was stopped at a position where the following was achieved (see Fig. 2).

(3) In this state, 3 m of the mixed solution was irradiated with ultraviolet rays emitted from a high-pressure mercury lamp from the substrate 1 side for 60 seconds (see FIG. 3).

As a result, 3 m of the mixed liquid was polymerized and hardened, and when the mold 2 was removed (see FIG. 4), a plastic molded lens 3 bonded to the substrate 1 was obtained.

[Example 4.5] (1) As the lens substrate 1, the type of glass has a refractive index +1
4 = 1.517, B5C- with Atsbe number 7-64.1
Exactly the same thing as in Example 1 was prepared except that Example 7 was replaced.

The mold 2 is exactly the same as that of Example 1.

(2) to (3) Using 3 m of a mixed solution having the composition described in each example in Table 1 below, 0.5% by weight of 1-hydroxycyclohexylphenyl ketone was added as a photopolymerization initiator, A plastic molded lens 3 bonded to a substrate 1 was manufactured in exactly the same manner as in Example 1.

[Test example]

In order to compare the physical properties of the plastic molded lens 3 manufactured in the example, the following test was conducted using the same mixed solution. The results are also shown in Table 1.

Refractive index> Two disk-shaped glass plates with a diameter of 30 mm coated with a release agent are placed at a 5 mm interval, the periphery is sealed with silicone rubber, and the mixed liquid is injected between the two glass plates. After that, the mixed solution was polymerized and cured by irradiating it with ultraviolet rays emitted from a high-pressure mercury lamp through a glass plate.

The ultraviolet rays were stopped when the cumulative amount reached 3000 mJ/ct.

The thus obtained disk-shaped plastic molded sample was removed from the glass plate, and its refractive index (measurement wavelength λ-587 nm) was measured using a commercially available refractometer.

Kuatsube number> Regarding the sample molded in the previous section (2), a predetermined number of refractive indices were measured while changing the measurement wavelength λ, and the Atsube number was determined using a predetermined calculation formula.

<Transmittance> Drop a small amount of the liquid mixture onto the first quartz plate, press the second quartz plate on top of it, narrow the gap between both quartz plates to 30 μm, maintain that state, and transmit the mixture through the quartz plate. The mixture was polymerized and cured by irradiating it with ultraviolet light emitted from a high-pressure mercury lamp.

In this state, the transmittance (measurement wavelength λ-300 to 700 nm) was measured with a spectrometer through both quartz plates, and then the transmittance at λ-360 nm was determined by correcting the interface reflectance. Since there is no absorption by the quartz plate at this wavelength, the transmittance of the quartz plate was set to 100%.

<Mold releasability> (1) First, a glass lens substrate 1 is used as a split mold.
and mold 2 was prepared.

The lens substrate 1 has a diameter of φ-30 mm and a convex curvature R of 80.
It is a 6-plane meniscus lens with a center thickness of t+=9 mm, and the type of glass is B5C-7.

The convex surface of the lens substrate 1 was previously treated with an alcohol solution of methacryloxypropyltrimethoxysilane.

The mold 2 is an iron mold having a concave surface with a curvature R3 of 80 mm, and the surface is plated with Ni.

(2) to (3) The mixed liquid was polymerized and cured in the same manner as in Example 1, and the obtained plastic molded sample was removed from the mold 2.

At this time, it was observed whether the molded sample was easily peeled off from the mold 2, and evaluated on the following three levels.

0---Easily released from the mold.

△------Difficult to release from mold.

×---------Not released from the mold.

<Hardness> The mixed solution was applied on a glass plate using the barcode method, and the results were obtained in Example 1.
Similarly, irradiate ultraviolet rays to polymerize and harden to a thickness of 100 mm.
After forming a .mu.m plastic molded film, a scratch test was conducted with pencils of various hardnesses, and the highest hardness that did not cause scratches on the surface of the film was recorded as the pencil hardness.

<Adhesion> After forming a plastic molded film with a thickness of 100 μm in the same manner as in the previous section <Hardness>, use a knife to make cross hatches (2 pitches, 10 pieces vertically and horizontally, 100 creases) on the surface of the film, and then Cellophane tape made by Nichihan ■ was pasted on.

Next, the tape was instantly peeled off, the number M of folds where the film remained on the glass plate was counted, and the number M was evaluated according to the following three grades.

Q------M = 100 △------M = 80 to 99 ×----------M-79 or less <Weather resistance> Plastic molded lens 3 manufactured in each example (substrate 1
) into the UV carbon fetometer.
After being left for a period of time, the presence/absence and degree of shape change was observed with the naked eye, and the decrease in transmittance was measured, and evaluated on the following three levels.

o-----No change in shape, no decrease in transmittance.

Δ---There is no change in shape, and there is a decrease in transmittance.

x - There is a change in shape or a significant decrease in transmittance.

<Heat resistance> Plastic molded lens 3 (substrate 1
After leaving it in a constant temperature room at 70 degrees Celsius and 60% humidity for 24 hours, visually observe the appearance such as shape and whitening, and
Evaluated in stages.

○---No change at all compared to before the test.

△---There are some changes.

×--- Significant change.

<Solvent resistance> Plastic molded lens 3 (substrate 1
After cleaning with an ultrasonic Freon cleaning machine, the appearance such as shape and whitening was observed with the naked eye and evaluated on the following three scales.

○---No change at all compared to before the test.

△---There are some changes.

x---- Significant change.

<Hot water resistance> Plastic molded lens 3 (substrate l) manufactured in each example
) was soaked in warm water at 50°C for 6 hours,
Appearance such as shape and whitening was observed with the naked eye and evaluated on the following three scales.

○------No change at all compared to before the test.

△---There are some changes.

x---One change is significant.

<Curing shrinkage rate> Based on JIS K-7112, use a pycnometer to measure the specific gravity of the mixed liquid before polymerization and curing and after curing, and divide the difference by the specific gravity after curing to determine the curing shrinkage rate. And so.

<Cold resistance> Plastic molded lens 3 (substrate 1) molded in each example
The lens was left at −40° C. for 24 hours and then at room temperature for 20 hours, and then the lens was observed with a microscope and evaluated on the following three scales.

0---No change at all compared to before the test.

△------There is some peeling from the board, changes in cranking, etc.

×------One change is remarkable.

The above results are shown in Table 1 below.

The symbols listed in the specific names in Table 1 refer to the following.

Table 1: phr is parts by weight 1: ε-caprolactone modified (average number of moles added 1) hydrogenated bisphenol A diacrylate 2: hydroxybivalylaldehyde modified trimethylolpropane diacrylate (trade name KAY manufactured by Nippon Kayaku ■)
ARAD R-604) 3 dicyclopentanyl acrylate 1 dipentaerythritol hexaacrylate (trade name KAYARAD DP manufactured by Nippon Kayaku) I8) Table (continued) <phr is parts by weight> [Effects of the invention] As described above, according to the present invention, a plastic molded lens with a small curing shrinkage rate of 7% or less, excellent transmittance, weather resistance, heat resistance, hot water resistance, solvent resistance, mold releasability, and high hardness is provided. provided.

[Brief explanation of the drawing]

FIGS. 1 to 4 are explanatory diagrams of the molding process when a plastic molded lens is molded in an embodiment of the present invention. [Explanation of symbols for main parts] 3m - Mixed liquid 3 - Plastic molded lens fee "1810I"1 1℃

Claims (1)

[Claims] (1) (a) Aliphatic (including cycloaliphatic) polyol and/or
Or a 2- to 4-functional urethane (meth)acrylate oligomer obtained by reacting an aliphatic (including cycloaliphatic) polyether polyol, an alicyclic polyisocyanate, and a hydroxy (meth)acrylate: 10 to 50 weight % (b) Mono- to di-functional unsaturated (meth)acrylate compound having an alicyclic alkyl or heteroartic ring structure: 40-90% by weight and (c) Tri- or more functional unsaturated (meth)acrylate compound: 0 ~30% by weight is polymerized in a mold, and the refractive index is 1.
Plastic molded lens with Abbe number of 60-44 and 48-1.52.