CN112118955B

CN112118955B - Automatic injection method of mold for monomer for episulfide optical material

Info

Publication number: CN112118955B
Application number: CN201980032511.2A
Authority: CN
Inventors: 张东奎; 金准燮
Original assignee: KOC Solution Co Ltd
Current assignee: Ml Technology Co ltd; Mitsui Chemicals Inc
Priority date: 2018-05-14
Filing date: 2019-04-22
Publication date: 2022-04-19
Anticipated expiration: 2039-04-22
Also published as: JP2021521040A; CN112118955A; JP7077424B2; KR102502637B1; KR20190130452A

Abstract

The present invention relates to a method for preparing an optical material by injecting an episulfide-based monomer solution into a cavity formed between a pair of molds whose peripheries are sealed, and more particularly, to a mold automatic injection method of a monomer for an episulfide-based optical material, which can be injected quantitatively in a short time using a visual recognition system while injecting an episulfide-based monomer solution into the cavity. The invention provides a mold automatic injection method of a monomer for an episulfide optical material, which comprises the following steps: (a) a step of preparing a monomer composition for an episulfide optical material having a solid-phase refractive index of 1.650 to 1.820 and a viscosity of 15 to 900cps (25 ℃); (b) a step of injecting a majority of the monomer composition into a cavity formed between a pair of molds sealed at their peripheries; and (c) after the step (b), injecting the monomer composition into the cavity, detecting a liquid level by using a visual recognition system, and ending the injection of the monomer composition if the liquid level is detected at the set final injection point. According to the present invention, the monomer solution for the episulfide optical material can be automatically injected into the mold in a quantitative amount so as not to be deficient or overflow.

Description

Automatic injection method of mold for monomer for episulfide optical material

Technical Field

The present invention relates to a method for preparing an optical material by injecting an episulfide monomer solution into a cavity formed between a pair of molds sealed at the periphery thereof, and more particularly, to a method for automatically injecting a monomer for an episulfide optical material into a mold, which can inject a fixed amount of the monomer for an episulfide optical material in a short time using a visual recognition system while injecting the episulfide monomer solution into the cavity.

Background

Among optical materials, plastic lenses have advantages of being light, not fragile, and good in workability as compared with glass lenses, and therefore, recently, plastic lenses are used more than glass lenses. These plastic lenses are manufactured by injecting a polymer compound called monomer (monomer) into a mold, curing the polymer compound, and then performing appropriate post-processing. That is, it is manufactured by injecting a monomer solution into a mold having an empty injection space (cavity) of a lens pattern.

As a related art, patent document 1 discloses a "moving distance setting device of a mold for manufacturing an ophthalmic lens".

In the patent document 1, in order to accurately determine the distance between the glass molds for manufacturing the spectacle lenses, a tape is attached to the outer peripheral surface of the glass mold in a state where the glass molds are spaced apart from each other by a mold chuck, and then a monomer solution is manually injected into the glass mold in which the tape attaching operation is completed.

However, the technique of manually injecting the monomer into the glass mold as disclosed in patent document 1 is completely dependent on the skill level of the injector, and therefore, there is a problem that a failure occurs according to the skill level and the work efficiency is lowered. In particular, it requires a very skilled technique to accurately inject the monomer in a predetermined amount each time, and therefore, there is a problem that bubbles are generated in the mold if unskilled.

In addition, since the liquid monomer generates volatile gas harmful to human body, it may adversely affect the health of workers when working for a long time.

The episulfide optical material has excellent properties of a high abbe number together with a high refractive index. An episulfide compound-based plastic lens is proposed in Korean granted patent No. 10-0681218. However, optical materials polymerized only with such episulfide compound-based monomers have problems in tensile strength, compressive strength, colorability, hard adhesion, productivity, etc., and in order to solve the problems, a method of copolymerizing two resins having different properties, that is, a method of copolymerizing an episulfide compound and a polythiol compound or a polyisocyanate compound thereto, has been proposed in korean patent laid-open publication No. 10-0417985, japanese patent laid-open publication No. 11-352302, etc. Saving production costs is one of the major concerns in the field of optical lenses including episulfide based optical materials. If the automatic injection can be performed in the automatic production facility without human hands, not only the productivity can be improved, but also the problem of harmfulness to the human body during the production process can be solved, but in spite of many attempts, it has been difficult to achieve the automatic injection. The high viscosity of the monomer composition, the difference in viscosity depending on the composition, and the difference in pouring time are also reasons for this.

Patent document 2 (korean patent No. 10-1383132) discloses an "automatic monomer injection apparatus for an ophthalmic lens and a method for producing an ophthalmic lens using the same". In patent document 2, in the step of injecting the monomer solution into the cavity formed by the pair of molds, the position of the lens mold is grasped by using a displacement sensor (laser sensor) that detects the position of the lens mold, and the water level of the raw material filled into the lens mold is detected by the second moving section, and the monomer injection amount of the injection nozzle is adjusted by the injection amount adjusting section, and when the monomer reaches a predetermined water level, the amount of the injected monomer is adjusted to 5mm of the first step and 10mm of the second step.

However, as in patent document 2, when the water level of the raw material (monomer composition) is detected by the displacement sensor, the viscosity of the monomer composition is higher than that of water, and therefore, the change in the water level is not a horizontal change but a two-dimensional, bilaterally symmetric parabolic shape, and therefore, there is a problem that it is difficult to accurately detect the water level in real time, and therefore, even if the injection amount is adjusted in steps, it is difficult to inject an accurate amount, and the injection amount is insufficient or excessive, resulting in product failure or contamination of the injection apparatus with the overflowing monomer.

In addition, the "plastic product manufacturing method and manufacturing apparatus" of patent document 3 (japanese patent No. 3707189) is a method for automating a process of injecting a plastic stock solution into a molding die in a plastic lens manufacturing process, which includes: a first process of setting a first flow rate and a first time by measuring a width between a first wall and a second wall inside a cavity, and injecting a plastic raw liquid into the cavity during the first flow rate and the first time; and in the second process, after the first process, the plastic stock solution is injected into the cavity at a second flow rate smaller than the first flow rate, so that a small amount of stock solution is injected only after the large-capacity stock solution is injected in a preset time, namely when the injection is about to be finished, thereby shortening the injection time and reducing the leakage rate.

However, in the injection method according to patent document 3, the injection time and the leakage amount can be reduced by reducing the injection amount and the injection time of the plastic raw material in steps in consideration of the space characteristics inside the cavity, but there is a problem that leakage failure still occurs and quantitative injection is difficult because the liquid level change characteristics of the monomer solution having high viscosity are not taken into consideration when the monomer is injected into the mold.

In patent document 4 (japanese laid-open patent No. 2007-80766), a method of molding a plastic lens is disclosed in which, when a liquid molding material is injected into a mold such as pouring a wine in a tilted wine glass, the injection is started in a state where an injection port is slightly shifted to one side from the upper midpoint so that the filling is performed without leaving air bubbles as much as possible in the mold, and after the injection is performed to a predetermined degree, the mold is rotated (tilted) so that the injection port is positioned at the upper midpoint so that a raw material monomer is filled.

However, although patent document 4 is a method suitable for injecting the raw material without leaving bubbles, it is still difficult to inject the raw material in an accurate amount.

[ Prior Art document ]

[ patent documents ]

(patent document 1)1 Korean Utility model No. 20-0236704

(patent document 2)2 Korean granted patent No. 10-1383132

(patent document 3)3 Japanese patent laid-open No. 3707189

(patent document 4)4 Japanese laid-open patent No. 2007 & 80766

(patent document 5)5 Korean granted patent gazette 10-0417985

(patent document 6)6 Japanese laid-open patent publication No. Hei 11-352302

(patent document 7)7 Korean granted patent gazette 10-0681218

Disclosure of Invention

Technical problem

In the prior art, as described above, a method of automatically injecting a monomer for an optical material into a mold has been proposed, but it is difficult to inject the monomer in an accurate amount, and an overflow or shortage phenomenon occurs. Further, since each monomer has a difference in curing speed and curing time, a difference in viscosity, and a difference in liquid level, and even monomers of the same series have differences in composition, a mechanical method of simply adjusting the injection amount or speed step by step cannot cope with the differences in monomer, and thus, there is a problem that accurate injection is difficult.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an automatic mold injection method for a monomer for an episulfide-based optical material, which can accurately inject a monomer composition for an episulfide-based optical material into a mold without an insufficient injection amount or an excessive injection amount.

In particular, an object of the present invention is to provide an automatic injection method of a mold for a monomer for an episulfide-based optical material, in which a monomer composition for an episulfide-based optical material is injected into a cavity of a mold in two steps, most of the monomer composition for an episulfide-based optical material is injected in a first step, then, in a second step, a liquid level of a episulfide-based monomer solution is detected by a visual recognition system, and if the liquid level is detected at a final injection point, the injection is stopped, thereby not only shortening the time but also allowing a quantitative injection so as not to cause overflow or shortage of the monomer solution.

Technical scheme

In order to achieve the above object, the present invention provides a method for automatically injecting a monomer for an episulfide-based optical material into a cavity formed between a pair of molds sealed at their peripheries, the method including: (a) a step of preparing a monomer composition for an episulfide optical material having a solid-phase refractive index of 1.650 to 1.820 and a viscosity of 15 to 900cps (25 ℃); (b) a step of injecting a majority of the monomer composition into the cavity; and (c) detecting the liquid level using a visual recognition system while injecting the monomer composition into the cavity after the step (b), and ending the injection of the monomer composition if the liquid level is detected at the set final injection point.

In the step (b), the monomer composition may be injected into the cavity at a predetermined weight or volume, or may be injected up to a predetermined region in the mold using a visual recognition system.

The vision recognition system photographs the outline of a mold and the liquid level of a monomer solution injected into the mold, and in order to detect a state in which the mold is disposed at an injection position, a first region located at a part of the outline of the mold and a second region located outside the mold may be set.

As described above, in the case where the visual recognition system of the first region and the second region is provided, it is preferable that the controller injects the majority of the monomer solution into the interior of the mold at the set first injection pressure when the outline of the mold is detected in the first region, and then injects the remaining amount of the monomer solution at a pressure lower than the first injection pressure, and at this time, if the liquid level is detected in the second region, the injection of the monomer solution is terminated.

In the first and second regions, the outline of the mold and the liquid level of the monomer solution are preferably detected by a change in the number of pixels.

In a preferred embodiment of the present invention, a virtual contour is expressed in a circular arc shape in the first region, and when the contour of the mold is detected in the first region, the shot position is adjusted so that the shot contour of the mold coincides with the virtual contour, and the position of the second region is moved together with the change in the position of the first region to detect the change in the liquid level.

In a preferred embodiment, the first region is a diagonal direction of the periphery of the mold, i.e., a position having both the X-direction information and the Y-direction information of the mold, and is a portion for confirming a change in position when the mold is mounted at the injection position, and the first region serves as a reference for the position movement of the second region, and the contour of the mold can be sensed when the mold is mounted at the injection position in the first region.

In a preferred embodiment, the second region is disposed outside a position close to a monomer injection port of the mold so as to fill the monomer solution without bubbles inside the mold, the second region being located approximately 1 to 2mm away from the mold profile.

In a preferred embodiment, the controller controls the syringe driving part such that 70 to 99% of the monomer solution is injected at a high pressure, i.e., rapidly, and the remaining amount is injected slowly at a lower pressure when the monomer solution, which is first injected into the syringe, is injected into the inside of the mold.

The monomer composition for an episulfide optical material includes a compound having one or more episulfide groups.

Preferably, the monomer composition for an episulfide-based optical material further includes one or more of a polythiol compound, sulfur, and a polyisocyanate compound.

The monomer composition for an episulfide optical material may further include an internal release agent, if necessary.

Preferably, the injection of the monomer composition is performed at a temperature in the range of-5 to 50 ℃.

Advantageous effects

According to the present invention, when a monomer for a chalcogenide optical material is injected into a mold, the liquid level is confirmed by a visual recognition system, and when the final injection point is reached, the injection is automatically stopped, so that the monomer solution can be quantitatively injected without causing shortage or overflow.

Further, since the amount and speed of injection are not simply mechanically adjusted, and injection is performed while confirming the liquid level by a visual recognition system when the amount of remaining injection is left, a constant amount of injection can be performed regardless of the difference in viscosity and the difference in liquid level shape of the monomer.

Further, since the step of injecting most of the monomer into the cavity in the mold at the first time can shorten the monomer injection time, it is easy to set the injection to be completed within a predetermined pouring time, and thus, the monomer can be injected in a quantitative manner in an optimum state before curing regardless of the difference between the curing speed and the curing time of the monomer.

According to the present invention, since high-quality episulfide lenses can be produced by automatic injection without defects due to insufficient or excessive injection amount, productivity can be greatly improved, production cost can be saved by reducing labor cost, and the problem that workers are directly exposed to monomers and the problem of abnormal operation or malfunction of equipment due to excessive injection of a monomer composition can be prevented.

Drawings

FIG. 1 is a schematic flow diagram of a lens manufacturing process according to an embodiment of the invention.

Fig. 2 is a structural view of an automatic monomer injection method according to an embodiment of the present invention.

Fig. 3 is a state in which the monomer solution is first drawn into the interior of the syringe in fig. 2.

Fig. 4 is a state in which the monomer solution is injected into the inside of the mold in fig. 3.

Fig. 5 is a view showing a state in which the monomer solution is filled in the inside of the mold in fig. 4.

Detailed Description

The automatic mold injection method of the monomer for an episulfide-based optical material of the present invention will be described in steps by preferred embodiments.

The invention provides a method for automatically injecting a mold of a monomer for an episulfide optical material, which comprises the following steps:

(a) a step of preparing a monomer composition for an episulfide optical material having a solid-phase refractive index of 1.650 to 1.820 and a viscosity of 15 to 900cps (25 ℃);

(b) a step of injecting a majority of the monomer composition into a cavity formed between a pair of molds sealed at their peripheries; and

(c) a step of detecting the liquid level using a visual recognition system while injecting the monomer composition into the cavity after the step (b), and ending the injection of the monomer composition when the liquid level is detected at the set final injection point.

The monomer compositions for an episulfide-based optical material mean compositions for optical materials each including a compound having one or more episulfide groups. In the present invention, the "monomer solution" means a liquid phase state in which the monomer composition has fluidity.

The monomer composition for an episulfide optical material has a solid phase refractive index of 1.650 to 1.820 and a viscosity of 15 to 900cps at a temperature of 25 ℃. More preferably, the viscosity is 20 to 500cps at a temperature of 25 ℃.

The compound having an episulfide group may be, for example, bis (2, 3-episulfide propyl) sulfide, bis (2, 3-episulfide propyl) disulfide, 2, 3-epoxypropyl (2, 3-episulfide propyl) sulfide, 1,3 and 1, 4-bis (. beta. -episulfide propyl thio) cyclohexane, episulfide compounds having an alicyclic skeleton such as 1,3 and 1, 4-bis (β -epithiopropylthiomethyl) cyclohexane, bis [4- (β -epithiopropylthio) cyclohexyl ] methane, 2-bis [4- (β -epithiopropylthio) cyclohexyl ] propane, bis [4- (β -epithiopropylthio) cyclohexyl ] sulfide; episulfide compounds having an aromatic skeleton, such as 1,3 and 1, 4-bis (β -epithiopropylthiomethyl) benzene, bis [4- (β -epithiopropylthio) phenyl ] methane, 2-bis [4- (β -epithiopropylthio) phenyl ] propane, bis [4- (β -epithiopropylthio) phenyl ] sulfide, and 4, 4-bis (β -epithiopropylthio) diphenyl; episulfide compounds having a dithiane chain skeleton such as 2, 5-bis (β -epithiopropylthiomethyl) -1, 4-dithiane, 2, 5-bis (β -epithiopropylthioethylthiomethyl) -1, 4-dithiane, 2, 5-bis (β -epithiopropylthioethyl) -1, 4-dithiane, 2,3, 5-tris (β -epithiopropylthioethyl) -1, 4-dithiane and the like; and episulfide compounds having an aliphatic skeleton such as 2- (2-. beta. -epithiopropylthioethylthio) -1, 3-bis (. beta. -epithiopropylthio) propane, 1, 2-bis [ (2-. beta. -epithiopropylthioethyl) thio ] -3- (. beta. -epithiopropylthio) propane, tetrakis (. beta. -epithiopropylthiomethyl) methane, 1,1, 1-tris (. beta. -epithiopropylthiomethyl) propane, and bis (. beta. -epithiopropylthio) sulfide. Further, as the episulfide compound, a halogen-substituted product such as a chlorine-substituted product or a bromine-substituted product of a compound having an episulfide group, an alkyl-substituted product, an alkoxy-substituted product, a nitro-substituted product, a prepolymer-type denatured product with polythiol, or the like can be used.

As the compound having the episulfide group, bis (2, 3-episulfide propyl) sulfide, bis (2, 3-episulfide propyl) disulfide, 2, 3-epoxypropyl (2, 3-episulfide propyl) sulfide, 2, 3-epoxypropyl (2, 3-episulfide propyl) disulfide, 1,3 and 1, 4-bis (. beta. -episulfide propylthio) cyclohexane, 1,3 and 1, 4-bis (. beta. -episulfide propylthio methyl) cyclohexane, 2, 5-bis (. beta. -episulfide propylthio methyl) -1, 4-dithiane, 2, 5-bis (. beta. -episulfide propylthio ethylthio methyl) -1, 4-dithiane, 2- (2-. beta. -episulfide propylthio ethylthio) -1, more than one of 3-di (beta-epithiopropylthio) propane.

In a preferred embodiment, the monomer composition for an episulfide-based optical material further includes one or more of a polythiol compound, sulfur, and a polyisocyanate compound.

The polythiol compound is not particularly limited, and one kind or a mixture of two or more kinds may be used as long as it is a compound having at least one thiol group. Preferably, a compound selected from bis (2-mercaptoethyl) sulfide, 4-mercaptomethyl-1, 8-dimercapto-3, 6-dithiooctane, 2, 3-bis (2-mercaptoethylthio) -3-propane-1-thiol, 2-bis (mercaptomethyl) -1, 3-propanedithiol, tetrakis (mercaptomethyl) methane; 2- (2-mercaptoethylthio) propane-1, 3-dithiol, 2- (2, 3-bis (2-mercaptoethylthio) propylthio) ethanethiol, bis (2, 3-dimercaptopropionyl) sulfide, bis (2, 3-dimercaptopropionyl) disulfide, 1, 2-bis (2-mercaptoethylthio) -3-mercaptopropane, 1, 2-bis (2- (2-mercaptoethylthio) -3-mercaptopropylthio) ethane, bis (2- (2-mercaptoethylthio) -3-mercaptopropyl) sulfide, bis (2- (2-mercaptoethylthio) -3-mercaptopropyl) disulfide, 2- (2-mercaptoethylthio) -3-2-mercapto-3- [ 3-mercaptopropylthio) disulfide -2- (2-mercaptoethylthio) -propylthio ] propylthio-propane-1-thiol, 2-bis- (3-mercapto-propionyloxymethyl) -butyl ester, 2- (2-mercaptoethylthio) -3- (2- (2- [ 3-mercapto-2- (2-mercaptoethylthio) -propylthio ] ethylthio) propane-1-thiol, (4R,11S) -4, 11-bis (mercaptomethyl) -3,6,9, 12-tetrathiatetradecane-1, 14-dithiol, (S) -3- ((R-2, 3-dimercaptopropyl) thio) propane-1, 2-dithiol, (4R,14R) -4, 14-bis (mercaptomethyl) -3,6,9,12, 15-pentathioheptane-1, 17-dithiol, (S) -3- ((R-3-mercapto-2- ((2-mercaptoethyl) thio) propyl) thio) -2- ((2-mercaptoethyl) thio) propane-1-thiol, 3' -dithiobis (propane-1, 2-dithiol), (7R,11S) -7, 11-bis (mercaptomethyl) -3,6,9,12, 15-pentathioheptadecane-1, 17-dithiol, (7R,12S) -7, 12-bis (mercaptomethyl) -3,6,9,10,13, 16-hexathiooctadecane-1, 18-dithiol, 5, 7-dimercaptomethyl-1, 11-dimercapto-3, 6, 9-trithioundecane, 4, 8-dimercaptomethyl-1, 11-dimercapto-3, 6, 9-trithioundecane, pentaerythritol tetrakis (3-mercaptopropionate), trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (2-mercaptoacetate), dipentaerythritol-ether-hexa (3-mercaptopropionate), 1,3, 3-tetrakis (mercaptomethylthio) propane, 1,1,2, 2-tetra (mercaptomethylthio) ethane, 4, 6-bis (mercaptomethylthio) -1, 3-dithiane and 2- (2, 2-bis (mercaptodimethylthio) ethyl) -1, 3-dithiane. One or a mixture of two or more compounds may be used as long as they have one or more thiol groups. Further, as the polythiol compound, an isocyanate or episulfide compound, a sulfurized cyclopropane compound, or a polymerization-modified product obtained by prepolymerization with a compound having an unsaturated bond as a resin modifier can also be used.

The polythiol compound is more preferably at least one of 2, 3-bis (2-mercaptoethylthio) propane-1-thiol (GST), 4, 8-dimercaptomethyl-1, 11-dimercapto-3, 6, 9-trithioundecane (FSH), 4, 7-dimercaptomethyl-1, 11-dimercapto-3, 6, 9-trithioundecane (FSH), and 5, 7-dimercaptomethyl-1, 11-dimercapto-3, 6, 9-trithioundecane (FSH).

In the monomer composition, the polythiol may preferably be contained in an amount of 1 to 15% by weight, more preferably 4 to 13% by weight, and still more preferably 5 to 11% by weight.

The polyisocyanate compound is not particularly limited, and a compound having at least one isocyanate group and/or isocyanate (thio) group can be used. For example, an aliphatic isocyanate compound selected from 2, 2-dimethylpentane diisocyanate, 2, 4-trimethylhexane diisocyanate, butene diisocyanate, 1, 3-butadiene-1, 4-diisocyanate, hexamethylene diisocyanate, 2,4, 4-trimethylhexamethylene diisocyanate, 1,6, 11-undecane triisocyanate, l,3, 6-hexamethylene triisocyanate, 1, 8-diisocyanate-4-isocyanatomethyloctane, bis (isocyanatoethyl) carbonate, bis (isocyanatoethyl) ether and the like; alicyclic isocyanate compounds such as isophorone diisocyanate, 1, 2-bis (isocyanatomethyl) cyclohexane, l, 3-bis (isocyanatomethyl) cyclohexane, l, 4-bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, dicyclohexyldimethylmethane isocyanate, and 2, 2-dimethyldicyclohexylmethane isocyanate; xylylene Diisocyanate (XDI), bis (isocyanatoethyl) benzene, bis (isocyanatopropyl) benzene, bis (isocyanatobutyl) benzene, bis (isocyanatomethyl) naphthalene, bis (isocyanatomethyl) diphenyl ether, phenylene diisocyanate, ethyl phenylene diisocyanate, isopropyl phenylene diisocyanate, dimethyl phenylene diisocyanate, diethyl phenylene diisocyanate, diisopropyl phenylene diisocyanate, trimethyl benzene triisocyanate, biphenyl diisocyanate, toluidine diisocyanate, 4' -diphenylmethane diisocyanate, 3' -dimethyl diphenylmethane-4, 4' -diisocyanate, bibenzyl-4, 4' -diisocyanate, bis (isocyanatophenyl) ethylene, 3' -dimethoxybiphenyl-4, aromatic isocyanate compounds such as 4' -diisocyanate, hexahydrophenylene diisocyanate and hexahydrodiphenylmethane-4, 4-diisocyanate; sulfur-containing aliphatic isocyanate compounds such as bis (isocyanatoethyl) sulfide, bis (isocyanatopropyl) sulfide, bis (isocyanatohexyl) sulfide, bis (isocyanatomethyl) sulfone, bis (isocyanatomethyl) disulfide, bis (isocyanatopropyl) disulfide, bis (isocyanatomethylthio) methane, bis (isocyanatoethylthio) ethane, bis (isocyanatomethylthio) ethane, and 1, 5-diisocyanato-2-isocyanatomethyl-3-thiopentane; diphenyl sulfide-2, 4-diisocyanate, diphenyl sulfide-4, 4 '-diisocyanate, 3' -dimethoxy-4, 4 '-diisocyanatodibenzyl sulfide, bis (4-isocyanatomethylbenzene) sulfide, 4-methoxybenzenethioglycol-3, 3-diisocyanate, diphenyl disulfide-4, 4' -diisocyanate, 2-dimethyldiphenyl disulfide-5, 5 '-diisocyanate, 3' -dimethyldiphenyl disulfide-6, 6 '-diisocyanate, 4' -dimethyldiphenyl disulfide-5, sulfur-containing aromatic isocyanate compounds such as 5' -diisocyanate, 3' -dimethoxydiphenyl disulfide-4, 4' -diisocyanate and 4,4' -dimethoxydiphenyl disulfide-3, 3' -diisocyanate; 2, 5-diisocyanatothiophene, 2, 5-bis (isocyanatomethyl) thiophene, 2, 5-diisocyanatotetrahydrothiophene, 2, 5-bis (isocyanatomethyl) tetrahydrothiophene, 3, 4-bis (isocyanatomethyl) tetrahydrothiophene, one or more compounds selected from the group consisting of sulfur-containing heterocyclic isocyanate compounds such as 2, 5-diisocyanato-1, 4-dithiane, 2, 5-bis (isocyanatomethyl) -1, 4-dithiane, 4, 5-diisocyanato-1, 3-dithiane, 4, 5-bis (isocyanatomethyl) -1, 3-dithiane and 4, 5-bis (isocyanatomethyl) -2-methyl-1, 3-dithiane. Further, any compound having at least 1 isocyanate group and/or isocyanate (thio) group may be used alone or in combination of two or more. Further, halogen-substituted products such as chlorine-substituted products and bromine-substituted products of these isocyanate compounds, alkyl-substituted products, alkoxy-substituted products, nitro-substituted products, or prepolymer-type denatured products with polyvalent alcohols or thiols, carbodiimide-denatured products, urea-denatured products, biuret-denatured products, or dimerization or trimerization reaction products may be used.

The polyisocyanate compound may preferably be one or more selected from the group consisting of isophorone diisocyanate (IPDI), Hexamethylene Diisocyanate (HDI), dicyclohexylmethane diisocyanate (H12MDI), Xylylene Diisocyanate (XDI), 3, 8-bis (isocyanatomethyl) tricyclo [5,2,1,02,6] decane, 3, 9-bis (isocyanatomethyl) tricyclo [5,2,1,02,6] decane, 4, 8-bis (isocyanatomethyl) tricyclo [5,2,1,02,6] decane, 2, 5-bis (isocyanatomethyl) bicyclo [2,2,1] heptane, and 2, 6-bis (isocyanatomethyl) bicyclo [2,2,1] heptane.

The monomer composition may also include sulfur. When sulfur is further included, the refractive index can be increased to 1.71 or more. The purity of the sulfur is preferably 98% or more, and when the purity is less than 98%, the transparency of the optical material may be reduced due to the influence of impurities. The purity of sulfur is more preferably 99.0% or more, and particularly preferably 99.5% or more. Commercially available sulfur is generally classified according to the shape and the purification method, and there are fine powder sulfur, colloidal sulfur, precipitated sulfur, crystal sulfur, sublimed sulfur, and the like, and in the present invention, any sulfur may be used as long as the purity is 98% or more. Preferably, when the composition for optical materials is prepared, fine powder sulfur of fine particles which are easily dissolved may be used. The amount of sulfur in the monomer composition is preferably 1 to 40% by weight, more preferably 2 to 30% by weight, and most preferably 3 to 22% by weight, relative to the total weight of the composition.

The monomer composition for an episulfide-based optical material may further include a polymerization catalyst. The polymerization catalyst is preferably at least one selected from the group consisting of amines, quaternary ammonium salts, quaternary phosphonium salts, tertiary phosphonium salts, secondary iodonium salts, and phosphine compounds. More preferably, one or more selected from quaternary ammonium salts, quaternary phosphonium salts, and phosphine compounds can be used. As the quaternary ammonium salt, tetra-n-butylammonium bromide, tetraphenylammonium bromide, triethylbenzylammonium chloride, hexadecyldimethylbenzylammonium chloride, 1-n-dodecylpyridinium chloride, etc. can be used. As the quaternary phosphonium salt, for example, tetra-n-butylphosphonium bromide, tetraphenylphosphonium bromide and the like can be used. As the phosphine compound, triphenylphosphine or the like can be used. In particular, preferably, the polymerization catalyst is a quaternary phosphonium salt including one of tetra-n-butylphosphonium bromide, tetraphenylphosphonium bromide. These polymerization catalysts may be used alone or in combination of two or more.

The composition for an episulfide optical material may further include a tin halide as a polymerization regulator. The tin halide preferably may be dibutyltin dichloride, dimethyltin dichloride or a compound containing a small amount of monomethyltin trichloride. More preferably, the monomethyltrichloride may contain 0.1 to 3.5% by weight. The episulfide optical material composition undergoes rapid reaction during polymerization and curing, and the viscosity of the composition rapidly increases. Since the rapid increase in viscosity can be suppressed by adjusting the reaction rate by the polymerization regulator, the above problem can be solved by using the polymerization regulator. The polymerization regulator is preferably used in an amount of 0.01 to 5% by weight relative to the total weight of the monomer composition. By adjusting the polymerization rate using the polymerization regulator, not only a sharp increase in viscosity can be suppressed, but also the polymerization yield can be improved and the generation of bubbles can be eliminated.

In the case where the composition for an episulfide optical material contains sulfur, it is preferable to perform polymerization after formation of a prepolymer, and in this case, it is preferable to further include an alkyl imidazole as a polymerization regulator in order to smoothly form a prepolymer. The alkyl imidazole particularly preferably includes 2-mercapto-1-methyl imidazole. The 2-mercapto-1-methylimidazole is preferably used in a purity of 98% or more. Preferably, it may comprise from 0.01 to 5 wt%, more preferably from 0.1 to 3 wt%, even more preferably from 0.15 to 1 wt% of the monomer composition.

The monomer composition may also include an internal mold release agent. By adding an internal mold release agent to the composition prior to the cast polymerization, the mold release properties after polymerization can be greatly improved. As the internal mold release agent, a phosphate ester compound, a silicone surfactant, a fluorine surfactant, an alkyl quaternary ammonium salt, or the like can be used alone or in combination of two or more. The internal mold release agent is preferably included in the polymerizable composition in an amount of 0.001 to 10% by weight.

The fluorine-based nonionic surfactant is a compound having a perfluoroalkyl group in the molecule, Unidyne DS-401^TM(Japan, Dajin Industrial Co., Ltd.), Unidyne DS-403^TM(Daiki Industrial Co., Ltd., Japan), Eftof EF 122A^TM(New autumn chemical Co., Ltd., Japan) Eftof EF 126^TM(New autumn chemical Co., Ltd., Japan) Eftof EF301^TM(New autumn chemical Co., Ltd.) and the like.

The silicone surfactant is a compound having a dimethylpolysiloxane group in the molecule, and includes Dow Q2-120A^TMAnd the like.

Alkyl quaternary ammonium salts are generally known as cationic surfactants and include halogen salts, phosphate salts, sulfate salts and the like, and examples of chloride salts include cetyltrimethylammonium chloride, octadecyltrimethylammonium chloride, cetyldimethylethylammonium chloride, triethyldecylammonium chloride, trioctylmethylammonium chloride, dimethylcyclohexyldecylammonium chloride (dimethylcyclohexyldecylammonium chloride) and the like.

Preferably, a phosphate compound is used as the internal mold release agent. The phosphate compound is prepared by adding phosphorus pentoxide (P)₂O₅) In which 2 to 3mol of an alcohol compound is added, and phosphate compounds in various forms can be obtained depending on the kind of the alcohol used. Typical examples thereof include those obtained by adding ethylene oxide or propylene oxide to an aliphatic alcohol, or adding ethylene oxide or propylene oxide to a nonylphenyl group or the like. When a phosphate ester compound to which ethylene oxide or propylene oxide is added is contained as an internal mold release agent in the polymerizable composition of the present invention, a product obtained by adding ethylene oxide or propylene oxide to the internal mold release agent can be obtainedAn optical material having good releasability and excellent quality is preferred. The composition of the present invention, as an internal mold release agent, is preferably used a resin composition selected from the group consisting of 4-PENPP [ polyoxyethylene nonyl phenyl ether phosphate (5% by weight of 5mol of ethylene oxide adduct, 80% by weight of 4mol of adduct, 10% by weight of 3mol of adduct, 5% by weight of 1mol of adduct)]8-PENPP [ polyoxyethylene nonylphenyl ether phosphate (3% by weight of 9mol of ethylene oxide adduct, 80% by weight of 8mol of adduct, 5% by weight of 9mol of adduct, 6% by weight of 7mol of adduct, 6% by weight of 6mol of adduct)]12-PENPP [ polyoxyethylene nonylphenyl ether phosphate (3% by weight of 13mol of ethylene oxide adduct, 80% by weight of 12mol of adduct, 8% by weight of 11mol of adduct, 3% by weight of 9mol of adduct, 6% by weight of 4mol of adduct)]16-PENPP [ polyoxyethylene nonylphenyl ether phosphate (3% by weight of 17mol of ethylene oxide adduct, 79% by weight of 16mol of adduct, 10% by weight of 15mol of adduct, 4% by weight of 14mol of adduct, 4% by weight of 13mol of adduct)]20-PENPP [ polyoxyethylene nonylphenyl ether phosphate (6% by weight of 21mol of ethylene oxide adduct, 76% by weight of 20mol of adduct, 7% by weight of 19mol of adduct, 6% by weight of 18mol of adduct, 5% by weight of 17mol of adduct)]4-PPNPP [ polyoxypropylene nonyl phenyl ether phosphate ester (5 mol propylene oxide adduct, 80 mol adduct, 4mol adduct, 10 mol adduct, 5mol adduct, 1mol adduct)]8-PPNPP [ polyoxypropylene nonylphenyl ether phosphate (3% by weight of 9mol of propylene oxide adduct, 80% by weight of 8mol of adduct, 5% by weight of 9mol of adduct, 6% by weight of 7mol of adduct, 6% by weight of 6mol of adduct)]12-PPNPP [ polyoxypropylene nonylphenyl ether phosphate (3% by weight of 13mol of propylene oxide adduct, 80% by weight of 12mol of adduct, 8% by weight of 11mol of adduct, 3% by weight of 9mol of adduct, 6% by weight of 4mol of adduct)]16-PPNPP [ polyoxypropylene nonylphenyl ether phosphate (3% by weight of 17mol of propylene oxide adduct, 79% by weight of 16mol of adduct, 10% by weight of 15mol of adduct, 4% by weight of 14mol of adduct, 4% by weight%13mol of adduct)]20-PPNPP [ polyoxypropylene nonylphenyl ether phosphate (6% by weight of 21mol of propylene oxide adduct, 76% by weight of 20mol of adduct, 7% by weight of 19mol of adduct, 6% by weight of 18mol of adduct, 5% by weight of 17mol of adduct)]And Zelec UN^TMMore than one of them. Various substituents including the halogen compound substituent of the phosphate ester compound can be used for the same purpose.

The monomer composition may further contain an olefin compound as a reactive resin modifier for the purpose of improving the optical properties of the optical material, for the purpose of adjusting impact resistance, specific gravity, monomer viscosity, and the like. Examples of the olefin compound which can be added as the resin modifier include benzyl acrylate, benzyl methacrylate, butoxyethyl acrylate, butoxymethyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxymethyl acrylate, epoxypropyl acrylate, phenoxyethyl acrylate, phenyl methacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, neopentyl glycol diacrylate, and the like, Neopentyl glycol dimethacrylate, ethylene glycol diglycidyl acrylate, ethylene glycol diglycidyl methacrylate, bisphenol A diacrylate, bisphenol A dimethacrylate, 2-bis (4-acryloyloxyethoxyphenyl) propane, 2-bis (4-methacryloyloxyethoxyphenyl) propane, 2-bis (4-acryloyloxydiethoxyphenyl) propane, 2-bis (4-methacryloyloxydiethoxyphenyl) propane, bisphenol F diacrylate, bisphenol F dimethacrylate, 1-bis (4-acryloyloxyethoxyphenyl) methane, 1-bis (4-methacryloyloxyethoxyphenyl) methane, 1-bis (4-acryloyloxydiethoxyphenyl) methane, bisphenol A diacrylate, bisphenol A, and mixtures thereof, (meth) acrylate compounds such as 1, 1-bis (4-methacryloyloxydiethoxyphenyl) methane, dimethylol tricyclodecane diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, glycerol diacrylate, glycerol dimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, methyl methacrylate, methylthioacrylate, methylthiomethacrylate, phenylthioacrylate, benzylthiomethacrylate, xylylenedithiol diacrylate, xylylenedithiol dimethacrylate, mercaptoethyldithiol diacrylate, mercaptoethylsulfide diacrylate and mercaptoethylsulfide dimethacrylate, allyl glycidyl ether, diallyl phthalate, allyl glycidyl ether, and allyl glycidyl ether, Allyl compounds such as diallyl terephthalate, diallyl isophthalate, diallyl carbonate, diethylene glycol diallyl carbonate, and vinyl compounds such as styrene, chlorostyrene, methylstyrene, bromostyrene, dibromostyrene, divinylbenzene, and 3, 9-divinylspirodi (m-dioxane), but the compounds that can be used are not limited to the above-exemplified compounds. These olefin compounds may be used alone or in combination of two or more.

The monomer composition of the present invention may further contain various additives such as a chain extender, a crosslinking agent, a light stabilizer, an antioxidant, an anti-coloring agent, an ultraviolet absorber, an organic dye, an inorganic pigment, a filler, and an adhesion enhancer, as required, according to a conventional method.

The injection of the monomer composition is preferably carried out at a temperature ranging from-5 to 50 ℃. By injecting the solution at an appropriate temperature, the pouring time can be appropriately maintained, and a high-quality optical material free from streaks and white turbidity can be obtained by a smooth polymerization reaction. More preferably, the temperature at the time of injection may be set at-5 to 30 ℃. Particularly preferably, when the temperature is set at-5 to 15 ℃, a high-refractive episulfide type optical lens having the highest quality can be manufactured.

In the step (b), the monomer composition may be injected into the cavity at a predetermined weight or volume, or may be injected up to a predetermined region in the mold using a visual recognition system. In the step (c), the liquid level is detected using a visual recognition system, and the injection of the monomer composition is terminated when the liquid level is detected at the set final injection point.

Preferred embodiments of the steps (b) and (c) are described below with reference to the accompanying drawings.

First, as shown in fig. 1, a method of automatically injecting a monomer solution into a mold for manufacturing an optical material such as a lens, which is substantially the same as the conventional method, includes a step of loading the mold (S10), a step of attaching a tape (S20), a step of opening the tape (S30), a step of injecting a monomer (S40), a step of sealing the tape (S50), and a step of unloading the mold (S60), and a subsequent process of separating the monomer from the mold after the monomer is cured, thereby completing the lens.

In the present embodiment, a specific method is proposed, which is a method of stopping the injection of the monomer solution when the liquid level is detected at the set final injection point by detecting the liquid level with a visual recognition system while injecting the monomer of the raw material tank into the cavity of the mold. As shown in fig. 2 to 5, a monomer solution (S) of a monomer solution tank (10) is first sucked into a syringe (20) whose volume is adjustable according to a cavity of a mold (M), then most of the monomer solution (S) injected into the syringe (20) is injected into the mold (M) at a high speed for a second time, the injection pressure injection residual amount is reduced, and finally whether the monomer solution (S) is filled in the mold (M) is confirmed by a visual recognition system, and then the injection is terminated.

In the present embodiment, as shown in fig. 2 to 5, the vision recognition system photographs the outline of a mold (M) and the liquid level (L1) of a monomer solution (S) injected into a cavity of the mold (M), and in order to detect a state in which the mold (M) is disposed at an injection position, a first region (a1) of a portion of the outline of the mold (M) and a second region (a2) located outside an injection gate of the mold (M) are disposed.

On the other hand, when the controller (C) detects the image signal photographed by the vision recognition system, that is, as shown in fig. 2, when the contour of the mold (M) is detected in the first area (a1), it recognizes that the mold (M) is placed at the injection position, and at this time, judges whether or not the photographed contour of the mold (M) coincides with a virtual contour (L) represented by a circular arc shape in the first area (a1), and if not, finely tunes the vision recognition system, that is, a photographing position adjustment step of adjusting the position of the vision camera so that the virtual contour (L) coincides with the contour of the mold (M).

In the above-described photographing position adjusting step, the position of the first region (a1) is adjusted while the position of the second region moves simultaneously equidistant together with the first region (a1), and thus, even if the installation position of the mold (M) in the injection device is slightly changed, the second region (a2) photographed by the vision recognition system photographs the same position to detect the change in the liquid level of the monomer solution.

The controller (C) analyzes the image photographed by the vision recognition system, senses whether or not the cavity is mounted at the injection position by grasping the volume of the cavity according to the type of the mold (M), and controls the opening and closing operations of the driving part (22) of the syringe (20) and the valve (V), thereby controlling the amount of the monomer solution (S) first sucked into the syringe (20) and the timing, injection pressure, and stop time of the second injection into the mold (M), and also finely adjusting the position of the vision recognition system, as shown in fig. 3.

In addition, the controller (C) sets the injection pressure differently according to the kinds of the mold (M) and the monomer solution (S) through an external input device such as a touch panel or a keyboard, and when a new mold or monomer solution is used, the controller (C) can perform the setting after finding the optimum injection pressure by storing data obtained by repeated tests.

In the present embodiment, the driving unit (22) moves the plunger (23) forward and backward by the power of the motor (not shown) to suck the monomer solution into the syringe (20) or inject the sucked monomer solution into the mold (M), but the present invention is not limited thereto, and various known driving methods may be used for the driving unit (22).

A preferred embodiment for injecting the monomer solution into the interior of the mold from the above-described structure is described as follows.

First, as shown in fig. 3, a monomer solution S is sucked into a syringe 20 for the first time so as to match the cavity capacity of a mold M according to the type of the mold M to be supplied, and at this time, a valve V provided between a raw material tank 10 and the syringe 20 is kept in an open state, and a drive unit 22 on the upper portion of the syringe 20 starts to fill a fixed amount of the monomer solution S into the syringe 20 in a state where an inflow of air or the like from the outside is blocked by a built-in check valve (not shown) at a nozzle 21 portion.

On the one hand, the valve (V) can also be opened and closed by the controller (C), and opened when the driving part (22) of the injector (20) performs suction operation by using a check valve, and closed automatically when performing discharge operation, namely injection to the mold side.

Next, as shown in fig. 4, when the outline of the mold (M) is detected in the first area (a1) in the image captured by the visual recognition system, the position of the camera is finely adjusted to match the virtual outline (L), thereby recognizing that the mold (M) is mounted at the injection position, and the drive unit (22) is actuated in the direction opposite to the first time, and the monomer solution (S) inside the syringe (20) is injected into the mold (M) through the nozzle (21), in which case the valve (V) is kept in the closed state, and the drive unit (22) injects only a preset amount of the monomer solution (S) in a state where the check valve provided in the nozzle (21) is opened, the preset amount being 70 to 99%, more preferably 90 to 98%, of the amount injected into the syringe (20) at one time.

In the above step, the monomer solution (S) is injected at the highest pressure within a range where no bubble is generated in the monomer solution, depending on the viscosity of the monomer solution, the thickness of the cavity inside the mold, and the like, thereby shortening the injection time of the monomer solution.

Finally, as described above, after most of the monomer solution (S) inside the syringe (20) is injected into the mold (M) by the driving of the driving part (22), the remaining monomer solution is carefully injected by relatively reducing the driving speed of the driving part (22), and at this time, as shown in fig. 5, until the liquid level of the monomer solution (S) is detected in the second region (a2) located outside the injection port (I) by the visual recognition system, the injection is performed, and the operation of the syringe driving part (22) is stopped due to the surface tension when the liquid level of the monomer solution (S) is detected in the second region (a2) located outside about 1 to 2mm from the outside of the injection port (I) of the mold (M), the injection of the monomer solution (S) is completed, and the mold is unloaded after the injection port (I) is closed by rewinding the sealing tape (T) opened in the subsequent process, the injection of the monomer solution (S) into the mold (M) is completed.

When the contour of the mold (M) in the first region (a1) is matched with the virtual contour (L) through the above process, most of the monomer solution (S) is injected into the interior of the mold (M) at a preset first injection pressure according to the kind of the supplied mold, and then, after the remaining amount is injected at a pressure relatively lower than the first injection pressure, it is confirmed whether the liquid level (L1) appears in the second region (a2) located outside the mold (M), if the liquid level (L1) appears, the injection of the monomer solution is ended, and if the liquid level does not appear, the monomer solution is injected into the second region (a2) at a fine pressure until the liquid level appears.

On the other hand, the outline of the mold or the liquid level of the monomer solution is detected by the change of the number of pixels in the first area and the second area, and the border portion of the outline of the mold and the liquid level of the monomer solution is displayed as a linear shadow according to the density difference between the air and the mold and the monomer solution, whereby it is known that the outline of the mold and the liquid level of the monomer solution are formed by the number of pixels formed by the linear shadow photographed in each area.

In this embodiment, since the contour of the mold (M) and the liquid level thickness of the monomer solution detected in the regions (a1, a2) are substantially constant, the number of detected pixels is also almost constant, but all peripheral devices are rapidly operated, and a person moves around the device or another device moves, so that a singular phenomenon is reflected in the mold or the monomer solution and a false detection occurs, and therefore, it is necessary to detect the amount of change in the number of detected pixels and the direction of progression of a shadow, in order to prevent a false detection due to various noises.

In the present embodiment, it is appropriate that the amount of the monomer solution injected at the first injection pressure is 70% to 99% of the total injection amount, but the present invention is not limited thereto, and the first injection amount may be set to be slightly different according to the kind of the mold and the viscosity of the monomer solution, as a matter of course. The amount of the monomer solution injected at the first injection pressure is more preferably 90% to 98% of the total injection amount.

According to the automatic monomer solution injection method of the embodiment of the present invention, most of the monomer solution is injected into the mold at an early stage quickly, that is, within a short time with a high pressure, and then the remaining amount is injected at a relatively slow speed until the liquid level of the monomer solution is detected in the second region until the cavity inside the mold is filled, so that not only can the time required to inject the monomer solution be shortened, but also an accurate amount can be injected without overflowing, thereby having advantages of improving productivity by shortening process time and manufacturing a lens with uniform quality, and also having advantages of not causing defects due to insufficient or excessive injection amount of the monomer and causing malfunction of a manufacturing apparatus, and the like.

According to the preferred embodiment of the present invention as described above, after most of the monomer solution having viscosity is rapidly injected into the cavity inside the mold at a high pressure for the first time, the remaining amount is slowly injected to be filled up by lowering the injection pressure using the visual recognition system in the last step, so that there is no fear that the injection capacity may be exceeded. In addition, after most of the monomer solution is injected into the mold in a short time, when the monomer solution in the second area is detected by the visual recognition system, the injection is stopped, so that no air bubbles exist, and a quantitative amount of the monomer solution is accurately injected to avoid the overflow or shortage phenomenon, thereby producing a lens with uniform quality, shortening the monomer injection time and extremely improving the monomer injection efficiency. Therefore, it is possible to prevent not only the occurrence of a defect due to the insufficient injection amount of the monomer solution, but also the occurrence of a trouble or malfunction of the apparatus due to the excessive injection of the monomer solution.

[ description of symbols ]

C: controller

I: injection port

L: virtual contour

L1: liquid level

M: die set

A1, a 2: detection area

S: monomer solution

T: sealing adhesive tape

V: valve with a valve body

10: raw material tank

20: syringe with a needle

21: nozzle with a nozzle body

22: driving part

23: and a plunger.

Claims

1. An automatic mold injection method for a monomer for an episulfide optical material, which is a method for injecting a monomer composition for an episulfide optical material into a cavity formed between a pair of molds sealed at the periphery, comprising:

(a) a step of preparing a monomer composition for an episulfide optical material, which has a solid-phase refractive index of 1.650 to 1.820 and a viscosity of 15 to 900cps (25 ℃);

(b) a step of injecting a majority of the monomer composition into the cavity; and

(c) a step of detecting the liquid level using a visual recognition system while injecting the monomer composition into the cavity after the step (b), and ending the injection of the monomer composition if the liquid level is detected at the set final injection point,

the vision recognition system photographs an outline of a mold and a liquid level of a monomer solution injected into the mold, and sets a first region located on a portion of the outline of the mold and a second region located outside the mold in order to detect a state where the mold is disposed at an injection position,

the visual recognition system injects most of the monomer solution into the mold at a set first injection pressure when the first region detects the contour of the mold, and then injects a residual amount of the monomer solution at a pressure lower than the first injection pressure, and at this time, if the liquid level is detected in the second region, the injection of the monomer solution is terminated.

2. The method of claim 1, wherein the profile of the mold and the level of the monomer solution are detected by a change in the number of pixels in the first region and the second region.

3. The method of claim 1, wherein the first region has a circular arc-shaped virtual contour, and when the contour of the mold is detected in the first region, the position of the mold is adjusted so that the contour of the mold matches the virtual contour, and the position of the second region is moved together with the change in the position of the first region to detect the change in the liquid level.

4. The method of claim 1, wherein the first region is provided at a position where the X-direction information and the Y-direction information of the mold are both present in the periphery of the mold.

5. The method of claim 1, wherein the step of injecting the monomer composition into the mold at the first injection pressure is performed in a range of 70 to 99% by volume of the cavity of the mold.

6. The method of automatically injecting a mold for a monomer for an episulfide-based optical material according to claim 1, wherein the monomer composition for an episulfide-based optical material contains a compound having one or more episulfide groups.

7. The method for automatically injecting a mold for a monomer for an episulfide-based optical material according to claim 6, wherein the compound having an episulfide group is a compound selected from the group consisting of bis (2, 3-episulfide propyl) sulfide, bis (2, 3-episulfide propyl) disulfide, 1, 3-bis (β -episulfide propylthio) cyclohexane, 1, 4-bis (β -episulfide propylthio) cyclohexane, 1, 3-bis (β -episulfide propylthiomethyl) cyclohexane, 1, 4-bis (β -episulfide propylthiomethyl) cyclohexane, 2, 5-bis (β -episulfide propylthiomethyl) -1, 4-dithiane, 2, 5-bis (β -episulfide propylthioethyl-thiomethyl) -1, 4-dithiane and 2- (2-beta-epithiopropylthioethylthio) -1, 3-di (beta-epithiopropylthio) propane.

8. The method of claim 6, wherein the monomer composition further comprises one or more of a polythiol compound, sulfur, and a polyisocyanate compound.

9. The method of claim 6, wherein the monomer composition for an episulfide optical material further comprises an internal release agent.

10. The method for mold automatic injection of a monomer for an episulfide-based optical material as claimed in claim 6, wherein the injection of the monomer composition is performed at a temperature ranging from-5 to 50 ℃.