Additives for long-term storage of isocyanate compounds, isocyanate mixtures comprising the same and methods of storing isocyanate compounds using the same

Abstract

The present invention relates to an additive for long-term storage of isocyanate compounds, an isocyanate mixture comprising the additive and a method for storing isocyanate compounds using the additive.

Description

Technical Field

[0001] This invention relates to additives for the long-term storage of isocyanate compounds, isocyanate mixtures containing said additives, and methods for storing isocyanate compounds using said additives. Background Technology

[0002] Isocyanate compounds are used as raw materials for polyurethanes in a wide variety of applications such as coatings, adhesives / pressure-sensitive adhesives, varnishes, foams, and optical materials. In fields requiring excellent appearance properties, especially in the case of polyurethanes used in optical applications requiring transparency, minimal discoloration is desirable. Therefore, it is important that not only does the polyurethane forming reaction not cause discoloration, but the isocyanate compound used as a raw material, particularly polyvalent isocyanates with two or more functionalities, itself does not undergo discoloration.

[0003] However, due to the high reactivity of isocyanate compounds, they are easily oxidized by atmospheric oxygen or form self-polymers during storage, thus easily deteriorating or fading. This also presents a problem in optical products using them, such as urethane lenses, where discoloration or clouding occurs.

[0004] In this regard, various methods have been studied and proposed to suppress discoloration in isocyanate compounds and products made using isocyanate compounds, such as sealing with nitrogen to prevent contact with air and storing under refrigeration, or storing after adding additives such as ultraviolet absorbers.

[0005] However, in order to use isocyanate compounds, they are moved from their storage location to the atmospheric environment. During this process, the isocyanate compounds may become discolored or cloudy depending on the moisture content of the atmosphere or changes in atmospheric temperature. When using discolored or cloudy isocyanate compounds to manufacture optical lenses, etc., there are problems of reduced clarity and deterioration in quality.

[0006] Furthermore, in methods of storing isocyanate compounds by adding additives to the isocyanate compounds, it is difficult to ensure long-term storage stability using conventional additives. Summary of the Invention

[0007] Technical issues The present invention was made to overcome the above-mentioned problems and aims to provide an additive for long-term storage of isocyanate compounds, an isocyanate mixture containing said additive, and a method for storing isocyanate compounds using said additive. In the present invention, by using an additive containing a hindered phenolic antioxidant, excellent storage stability is achieved even when the isocyanate compound is stored for a long time.

[0008] Furthermore, the present invention aims to provide an additive for the long-term storage of isocyanate compounds, an isocyanate mixture containing said additive, and a method for storing isocyanate compounds using said additive, which enables the production of polyurethane resins with excellent thermal stability using isocyanate compounds that have been stored for a long time.

[0009] Furthermore, the present invention aims to provide an additive for the long-term storage of isocyanate compounds, an isocyanate mixture containing said additive, and a method for storing isocyanate compounds using said additive, which enables the production of transparent optical materials (e.g., optical lenses) that are less prone to causing defect-inducing factors using isocyanate compounds that have been stored for a long time.

[0010] Technical solution To address the aforementioned problems, the additives for long-term storage of isocyanate compounds according to the present invention may contain hindered phenolic antioxidants.

[0011] In a preferred embodiment of the invention, the additive for long-term storage of isocyanate compounds according to the invention may further comprise one or more compounds selected from those represented by chemical formula 2 and those represented by chemical formula 3.

[0012] [Chemical Formula 2]

[0013] In the above chemical formula 2, R7 is -H, a C1 to C12 straight-chain alkyl group, or a C3 to C12 branched alkyl group.

[0014] [Chemical Formula 3]

[0015] In the above chemical formula 3, R8 is -H, a C1 to C12 straight-chain alkyl group, or a C3 to C12 branched alkyl group.

[0016] In a preferred embodiment of the invention, the additive for long-term storage of isocyanate compounds according to the invention may contain a compound represented by chemical formula 2 above, a hindered phenolic antioxidant, and a compound represented by chemical formula 3 above in a weight ratio of 1:0.005 to 2.0:0.004 to 2.0.

[0017] In a preferred embodiment of the present invention, the hindered phenolic antioxidant may be a compound containing two or more hydroxyl groups.

[0018] In a preferred embodiment of the present invention, the hindered phenolic antioxidant may comprise a compound represented by the following chemical formula 1.

[0019] [Chemical Formula 1]

[0020] In the above chemical formula 1, R1 and R2 are each hydroxyl groups, and R3 is -H, a C1 to C12 straight-chain alkyl group, or a C3 to C12 branched-chain alkyl group.

[0021] In a preferred embodiment of the present invention, the hindered phenolic antioxidant may comprise a compound represented by the following chemical formula 1-1.

[0022] [Chemical Formula 1-1]

[0023] In the above chemical formula 1-1, R4, R5 and R6 are each independently -H or C1 to C3 straight-chain alkyl.

[0024] In a preferred embodiment of the present invention, the isocyanate compound may comprise one or more selected from 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, isophthalimethylene diisocyanate, terephthalimethylene diisocyanate, and orthophthalimethylene diisocyanate.

[0025] Meanwhile, the isocyanate mixture of the present invention may contain isocyanate compounds; and additives for long-term storage of isocyanate compounds, and the additives for long-term storage of isocyanate compounds may contain hindered phenolic antioxidants.

[0026] In a preferred embodiment of the invention, the isocyanate mixture of the invention may contain an isocyanate compound and an additive for long-term storage of the isocyanate compound in a weight ratio of 1:0.001 to 0.3.

[0027] In a preferred embodiment of the invention, the additive for long-term storage of isocyanate compounds may comprise a compound represented by the following chemical formula 2, a hindered phenolic antioxidant, and a compound represented by the following chemical formula 3.

[0028] [Chemical Formula 2]

[0029] In the above chemical formula 2, R7 is -H, a C1 to C12 straight-chain alkyl group, or a C3 to C12 branched alkyl group.

[0030] [Chemical Formula 3]

[0031] In the above chemical formula 3, R8 is -H, a C1 to C12 straight-chain alkyl group, or a C3 to C12 branched alkyl group.

[0032] In a preferred embodiment of the invention, the additive for long-term storage of isocyanate compounds may contain a compound represented by chemical formula 2 above, a hindered phenolic antioxidant, and a compound represented by chemical formula 3 above in a weight ratio of 1:0.005 to 2.0:0.004 to 2.0.

[0033] Furthermore, the method for storing isocyanate compounds according to the present invention may include: a first step of mixing the isocyanate compound and an additive for long-term storage of the isocyanate compound to prepare an isocyanate mixture; and a second step of storing the isocyanate mixture in a nitrogen-purged atmosphere at a temperature of 20°C or lower and a humidity of 1%RH or lower, wherein the additive for long-term storage of the isocyanate compound may contain a hindered phenolic antioxidant.

[0034] In a preferred embodiment of the invention, the second step can be to store the isocyanate mixture in a nitrogen-substituted atmosphere at a temperature of 0°C to 20°C and a humidity of 0.0001%RH to 1%RH.

[0035] Meanwhile, the optical lens of the present invention may contain the isocyanate mixture of the present invention.

[0036] In a preferred embodiment of the invention, the optical lens may have a haze of 0.3% or less.

[0037] Furthermore, the non-foamed resin of the present invention may contain the isocyanate mixture of the present invention.

[0038] In a preferred embodiment of the invention, the non-foamed resin is used in coatings, adhesives, sealants, or elastomers.

[0039] Beneficial effects The additive for long-term storage of isocyanate compounds according to the present invention, the isocyanate mixture containing the additive, and the method for storing isocyanate compounds using the additive exhibit excellent storage stability even when the isocyanate compounds are stored for a long time by using a hindered phenolic antioxidant.

[0040] Furthermore, the additive for long-term storage of isocyanate compounds according to the present invention, the isocyanate mixture containing the additive, and the method for storing isocyanate compounds using the additive enable the production of polyurethane resins with excellent thermal stability using isocyanate compounds that have been stored for a long time.

[0041] Furthermore, additives for the long-term storage of isocyanate compounds, isocyanate mixtures containing said additives, and methods for storing isocyanate compounds using said additives enable the production of transparent optical materials that are less prone to causing defect-inducing factors. Detailed Implementation

[0042] The invention will be described in more detail below.

[0043] Various methods have been studied and proposed as conventional methods for suppressing discoloration in isocyanate compounds and products manufactured using isocyanate compounds. These include methods such as sealing with nitrogen to prevent contact with air and storing under refrigeration, or storing after adding additives such as ultraviolet absorbers. However, in order to use isocyanate compounds, they are moved from their storage location to the atmospheric environment. During such a process, the isocyanate compounds may become discolored or cloudy depending on the atmospheric moisture content or temperature changes. When using discolored or cloudy isocyanate compounds to manufacture optical lenses, etc., there are problems of reduced clarity and deterioration in quality. Furthermore, in methods of storing isocyanate compounds by adding additives, it is difficult to ensure long-term storage stability using conventional additives.

[0044] Therefore, by introducing an additive for the long-term storage of isocyanate compounds containing hindered phenolic antioxidants, the present invention exhibits excellent storage stability even when isocyanate compounds are stored for extended periods.

[0045] The additives for long-term storage of isocyanate compounds according to the present invention may contain hindered phenolic antioxidants.

[0046] Specifically, hindered phenolic antioxidants can be compounds containing two or more hydroxyl groups, and preferably compounds containing two hydroxyl groups.

[0047] More specifically, hindered phenolic antioxidants may comprise compounds represented by the following chemical formula 1, and preferably may comprise compounds represented by the following chemical formulas 1-1.

[0048] [Chemical Formula 1]

[0049] In the above chemical formula 1, R1 and R2 are each hydroxyl groups, and R3 is -H, a C1 to C12 straight-chain alkyl group, or a C3 to C12 branched-chain alkyl group.

[0050] [Chemical Formula 1-1]

[0051] In the above chemical formula 1-1, R4, R5 and R6 are each independently -H or C1 to C3 straight-chain alkyl.

[0052] Furthermore, the additive for long-term storage of isocyanate compounds according to the present invention may also contain one or more compounds selected from those represented by Chemical Formula 2 and those represented by Chemical Formula 3, and preferably may also contain compounds represented by Chemical Formula 2 and those represented by Chemical Formula 3.

[0053] [Chemical Formula 2]

[0054] In the above chemical formula 2, R7 is -H, a C1 to C12 straight-chain alkyl or a C3 to C12 branched alkyl, preferably a C1 to C12 straight-chain alkyl, and more preferably a C1 to C3 straight-chain alkyl.

[0055] [Chemical Formula 3]

[0056] In the above chemical formula 3, R8 is -H, a C1 to C12 straight-chain alkyl or a C3 to C12 branched alkyl, preferably a C1 to C12 straight-chain alkyl, and more preferably a C1 to C3 straight-chain alkyl.

[0057] Furthermore, the additive for long-term storage of isocyanate compounds according to the present invention may contain the compound represented by Chemical Formula 2 above, a hindered phenolic antioxidant, and the compound represented by Chemical Formula 3 above in a weight ratio of 1:0.005 to 2.0:0.004 to 2.0, preferably 1:0.01 to 2.0:0.005 to 2.0, more preferably 1:0.05 to 0.5:0.01 to 0.3, even more preferably 1:0.07 to 0.3:0.02 to 0.15, and most preferably 1:0.08 to 0.2:0.04 to 0.1. If the weight ratio of the compound represented by Chemical Formula 2 above to the hindered phenolic antioxidant is less than 1:0.005, not only may the storage stability decrease, but the increase in haze may also lead to the problem of opacity in optical lenses made using it. If the ratio is greater than 1:2.0, there may be a problem of yellowing in isocyanate compounds and / or optical lenses made using said isocyanate compounds.

[0058] Furthermore, the isocyanate compounds of the present invention may include one or more selected from 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,3-cyclohexene diisocyanate, 1,4-cyclohexene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, isophthalimethylene diisocyanate, terephthalimethylene diisocyanate, and orthophthalimethylene diisocyanate, and preferably may include isophthalimethylene diisocyanate.

[0059] Furthermore, the isocyanate mixture of the present invention may contain an isocyanate compound and an additive for long-term storage of the isocyanate compound. Here, the isocyanate compound and the additive for long-term storage of the isocyanate compound are the same as described above.

[0060] Furthermore, the isocyanate mixture of the present invention may contain the isocyanate compound and an additive for long-term storage of the isocyanate compound in a weight ratio of 1:0.001 to 0.3, preferably 1:0.01 to 0.2, and more preferably 1:0.03 to 0.1. If the weight ratio is less than 1:0.001, not only will storage stability decrease, causing turbidity, but the increased haze may also lead to opacity in optical lenses made using the isocyanate compound. If it is greater than 1:0.3, yellowing may occur in the isocyanate compound and / or in optical lenses made using the isocyanate compound.

[0061] Furthermore, the method for storing isocyanate compounds according to the present invention may include: a first step of mixing the isocyanate compound and an additive for long-term storage of the isocyanate compound to prepare an isocyanate mixture; and a second step of storing the isocyanate mixture under a nitrogen-purified atmosphere at a temperature of 20°C or lower, preferably 0°C to 20°C, and more preferably 5°C to 15°C, and a humidity of 1%RH or lower, preferably 0.0001%RH to 1%RH, and more preferably 0.001%RH to 0.1%RH. Here, the isocyanate compound and the additive for long-term storage of the isocyanate compound are the same as described above.

[0062] Furthermore, if the storage temperature in the second step exceeds 20°C, not only will storage stability decrease, but the increased haze may also lead to opacity in optical lenses made using the isocyanate compound and / or prevent the use of the isocyanate compound to manufacture optical lenses. Similarly, if the storage humidity in the second step exceeds 1%RH, not only will storage stability decrease, but the increased haze may also lead to opacity in optical lenses made using the compound.

[0063] Meanwhile, the optical lens of the present invention may contain the isocyanate mixture of the present invention and may have a haze of 0.3% or less, preferably 0.1% to 0.28%, and more preferably 0.2% to 0.26%.

[0064] Furthermore, the non-foamed resin of the present invention may contain the isocyanate mixture of the present invention.

[0065] The non-foamed resin of the present invention is a resin that does not have a foam shape and can be used in coatings, adhesives, sealants or elastomers, but is not limited thereto.

[0066] As a specific example, the non-foaming resin of the present invention can be a reaction product of the isocyanate mixture of the present invention and a component containing active hydrogen groups. The component containing active hydrogen groups may include polyol components (comprising mainly polyols having two or more hydroxyl groups), polythiols (comprising mainly polythiols having two or more thiol groups), polyamine components (comprising mainly polyamine compounds having two or more amino groups), etc. As a preferred example, the component containing active hydrogen groups can be a raw material required for the production of polyurethane resin.

[0067] Meanwhile, the non-foamed resin of the present invention used in coatings, adhesives, sealants or elastomers can be, but is not limited to, a raw material for manufacturing automobiles, ships, flexible packaging, food packaging, building materials, paints, inks, solar cells, microcapsules, adhesives for displays, optical materials and fuel cells.

[0068] Furthermore, the method for producing isocyanate compounds according to the present invention will be described below by way of example.

[0069] Isocyanate compounds are synthesized by reacting amine compounds with phosgene in a solvent.

[0070] As solvents used in the phosgenation reaction, aromatic hydrocarbon solvents such as benzene, toluene, xylene or ethylbenzene; chlorinated aromatic hydrocarbon solvents such as monochlorobenzene, 1,2-dichlorobenzene or 1,4-dichlorobenzene; or chlorinated hydrocarbon solvents such as dichloromethane, chloroform or carbon tetrachloride, and two or more of them can be used in combination.

[0071] The amine compound used in the phosgenation reaction can be, for example, an amine compound obtained by hydrogenating a nitro compound or its hydrochloride salt. Specifically, the amine compound can be one or more selected from the group consisting of 1,4-tetramethylenediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,3-cyclohexylenediamine, 1,4-cyclohexylenediamine, isophoronediamine, diamine, diphenylmethylenediamine, dicyclohexylmethylenediamine, toluenediamine, m-phenylenediamine, p-phenylenediamine, o-phenylenediamine and their salts, and preferably m-phenylenediamine, p-phenylenediamine, o-phenylenediamine or their salts.

[0072] Based on 100 parts by weight of solvent, the amine compound may be included in an amount of 1 to 20 parts by weight. If the content of the amine compound is greater than 20 parts by weight, there is a concern that a large amount of the amine compound may precipitate out. It may preferably be included in an amount of 1 to 15 parts by weight or 3 to 10 parts by weight.

[0073] Specifically, the phosgenation reaction can be carried out by the following methods: a direct phosgenation method in which an amine compound reacts directly with phosgene (Method 1); a method in which an amine compound reacts with anhydrous hydrochloric acid to form an amine-hydrochloride compound, and then the formed salt reacts with phosgene (Method 2); or a method in which an amine compound reacts with carbonic acid to form an aliphatic amine-carbonate compound, and then the formed salt reacts with phosgene (Method 3).

[0074] The direct phosgenation method described in Method 1 above can be carried out by reacting an amine compound with phosgene in an organic solvent. Here, the phosgene can be added all at once at the start of the reaction, or a portion can be added at the start of the reaction, with the remaining portion added in stages during the reaction.

[0075] Meanwhile, Method 1 above can be carried out through the following steps: a first step of dissolving a portion of phosgene in a solvent and then adding an amine compound; and a second step of adding the remaining portion of phosgene after the addition of the amine compound and allowing the reaction to proceed. Here, the first step is preferably carried out at a temperature of -15°C to -10°C to prevent leakage of the highly toxic phosgene and also to prevent rapid heating during the addition of the amine compound. Furthermore, the phosgenation reaction in the second step can be controlled at 120°C to 140°C, allowing the reaction to proceed at an appropriate rate without concern for the decomposition of the amine compound.

[0076] In the case of method 2 above, it can be carried out by the following steps: reacting the amine compound with hydrochloric acid in an organic solvent to form an amine-hydrochloride compound, and then adding phosgene to allow the reaction to proceed. The formation of the amine-hydrochloride compound can be carried out at a temperature of 30°C or lower, preferably at a temperature of about 23±5°C, and the reaction after the addition of phosgene can be controlled at 120°C to 140°C. When carried out under such temperature conditions, the solubility of the amine-hydrochloride compound increases, and the thermal decomposition of the isocyanate is prevented, allowing for the production of high-purity isocyanate compounds in high yield.

[0077] In the case of method 3 above, it can be carried out by the following steps: reacting the amine compound with carbonic acid in a solvent to form an amine-carbonate compound, and then adding phosgene to allow the reaction to proceed. Here, the formation of the amine-carbonate compound can be carried out at a temperature of 30°C or lower, preferably at a temperature of about 23±5°C, and the reaction after the addition of phosgene can be controlled to 80°C to 180°C. Preferably, the reaction can be controlled to a range of 100°C or higher, or 120°C or higher, and 150°C or lower, or 140°C or lower. When carried out under such temperature conditions, the solubility of the amine-carbonate compound increases, and thermal decomposition of the isocyanate is prevented, allowing for the production of high-purity isocyanate compounds in high yield.

[0078] After the reaction with phosgene is completed according to the various methods, optional further processes such as nitrogen bubbling and solvent removal processes such as distillation can be carried out to remove unreacted phosgene and hydrogen chloride gas. These processes can be carried out according to conventional methods.

[0079] The invention will be described in more detail below by way of examples. However, the following examples do not limit the scope of the invention and should be construed as being intended to aid in understanding the invention.

[0080] Example 1: Preparation of an additive for long-term storage of isocyanate compounds A compound represented by Chemical Formula 2-1, an antioxidant, and a compound represented by Chemical Formula 3-1 are mixed in a weight ratio of 1:0.1:0.06 to prepare an additive for the long-term storage of isocyanate compounds. Here, a hindered phenolic antioxidant is used as the antioxidant, and a compound represented by Chemical Formula 1-2 is used as the hindered phenolic antioxidant.

[0081] [Chemical Formula 1-2]

[0082] In the above chemical formulas 1-2, R4, R5 and R6 are each methyl groups.

[0083] [Chemical Formula 2-1]

[0084] In the above chemical formula 2-1, R7 is a methyl group.

[0085] [Chemical Formula 3-1]

[0086] In the above chemical formula 3-1, R8 is a methyl group.

[0087] Example 2: Preparation of an additive for long-term storage of isocyanate compounds The isocyanate compound storage solution was prepared in the same manner as in Example 1. However, unlike Example 1, a compound represented by the following chemical formula 4 was used as an antioxidant.

[0088] [Chemical Formula 4]

[0089] Example 3: Preparation of an additive for long-term storage of isocyanate compounds The isocyanate compound storage solution was prepared in the same manner as in Example 1. However, unlike Example 1, a compound represented by the following chemical formula 5 was used as an antioxidant.

[0090] [Chemical Formula 5]

[0091] Example 4: Preparation of an additive for long-term storage of isocyanate compounds The isocyanate compound storage solution was prepared in the same manner as in Example 1. However, unlike Example 1, a compound represented by the following chemical formula 6 was used as an antioxidant.

[0092] [Chemical Formula 6]

[0093] Example 5: Preparation of an additive for long-term storage of isocyanate compounds The isocyanate compound storage solution was prepared in the same manner as in Example 1. However, unlike Example 1, a compound represented by the following chemical formula 7 was used as an antioxidant.

[0094] [Chemical Formula 7]

[0095] In the above chemical formula 7, n is an integer that satisfies 3.

[0096] Example 6: Preparation of an additive for long-term storage of isocyanate compounds The isocyanate compound storage solution was prepared in the same manner as in Example 1. However, unlike Example 1, a compound represented by the following chemical formula 8 was used as an antioxidant.

[0097] [Chemical Formula 8]

[0098] In the above chemical formula 8, m is an integer that satisfies 4.

[0099] Example 7: Preparation of an additive for long-term storage of isocyanate compounds The isocyanate compound storage solution was prepared in the same manner as in Example 1. However, unlike Example 1, a compound represented by the following chemical formula 9 was used as an antioxidant.

[0100] [Chemical Formula 9]

[0101] Experimental Example 1: Evaluation of the appearance of isocyanate compounds with additives for long-term storage of isocyanate compounds. Prepare a 1 kg solution of isocyanate m-xylene diisocyanate (m-XDI) as the isocyanate compound, and add 60 g of each of the additives prepared in Examples 1 to 7 for long-term storage of the isocyanate compound to the prepared m-XDI solution and mix them to prepare an m-XDI mixture.

[0102] Each of the prepared m-XDI mixture and the m-XDI solution without additives (=reference) was stored for one year under a nitrogen-purged atmosphere at 15°C and 0.1% RH. Afterward, the appearance of the stored m-XDI mixture was assessed by visual inspection. When the mixture was transparent, the appearance was rated ×; when it appeared blurred when illuminated, the appearance was rated △; and when it appeared blurred only by visual inspection, the appearance was rated ○. The results are shown in Table 1 below.

[0103] [Table 1]

[0104] As can be confirmed from Table 1 above, the m-XDI mixtures using the additives for long-term storage of isocyanate compounds prepared in Examples 1, 2, 6 and 7 exhibit excellent storage stability.

[0105] Manufacturing Example 1: Manufacturing of Optical Lenses Each of 20.8 g of the m-XDI mixture prepared in Example 1 and the m-XDI solution without additives (=reference), 0.04 g of ZELEC® UN (manufactured by Stepan) as an internal release agent, and 0.04 g of Biosorb® 583 (manufactured by Sakai Chemical Industry Co., Ltd) as a UV absorber was stirred and mixed at room temperature (=23°C) for 20 minutes to prepare a mixture. 0.002 g of DBTC (dibutyltin dichloride) was added to the prepared mixture and stirred for 10 minutes. 19.2 g of 2,3-bis(2-thioethylthio)propane-1-thiol was then added, and the mixture was stirred for 1 hour while degassing at 5 mbar to prepare a composition for polyisocyanate polymerization.

[0106] The composition for polyisocyanate polymerization was prepared by filtering through a 1 μm PTFE filter and then injected into a mold consisting of a glass mold and adhesive tape. The mold was then placed in an oven, and polymerization was carried out for 20 hours while the temperature was gradually increased from 10°C to 120°C. After polymerization, the mold was removed from the oven and demolded to obtain individual plastic optical lenses. The obtained optical lenses were annealed at 120°C for 6 hours to produce optical lenses with a thickness of 9 mm.

[0107] Experiment Example 3: Color Difference Measurement, Haze Measurement and Evaluation According to ASTM E313, the chromatic aberration values ​​(Lo) of each optical lens produced in Manufacturing Example 1 were measured using an Ultrascan Pro from HunterLab (light source: D65). value, a value, b The values ​​(value), yellowness (YI), and haze were measured, and the results are shown in Table 2 below. Furthermore, for optical lenses measured by visual inspection, any opacity factors identified in the whole or in a portion thereof were assessed as haze defects. An evaluation of ○ was given when the degree of haze defect was uniformly distributed globally; a evaluation of △ was given when one or more circular haze defect elements were present; and an evaluation of × was given when the lens was in a transparent state without any haze defect elements. The results are shown in Table 2 below.

[0108] [Table 2]

[0109] To manufacture transparent optical lenses, not only must the transparency be excellent, but the impurities must also be minimal. The smaller the chromatic aberration value, the better the resistance to discoloration, and the greater the variation in haze, the higher the degree of turbidity that has already occurred.

[0110] As can be confirmed from Table 2, the optical lens manufactured using the additive for long-term storage of isocyanate compounds in Example 1 not only has excellent transparency but also low haze and no haze defects. In contrast, the optical lenses manufactured using the additives for long-term storage of isocyanate compounds in Examples 2 and 4 to 7 have reduced transparency, and the optical lens manufactured using the additive for long-term storage of isocyanate compounds in Example 3 and the optical lens manufactured without the additive for long-term storage of isocyanate compounds (=reference) are slightly opaque due to high haze.

[0111] The specific embodiments have been illustrated and described above. However, the present invention is not limited to the above embodiments, and those skilled in the art can make various modifications without departing from the spirit and intent of the invention as set forth in the appended claims.

Claims

1. An additive for the long-term storage of isocyanate compounds, comprising a hindered phenolic antioxidant.

2. The additive according to claim 1, wherein the additive further comprises one or more compounds selected from those represented by chemical formula 2 and those represented by chemical formula 3: [Chemical Formula 2] [Chemical Formula 3] In the above chemical formula 2, R7 is -H, a C1 to C12 straight-chain alkyl group, or a C3 to C12 branched alkyl group, and In the above chemical formula 3, R8 is -H, a C1 to C12 straight-chain alkyl group, or a C3 to C12 branched alkyl group.

3. The additive according to claim 2, wherein the additive comprises, in a weight ratio of 1:0.005 to 2.0:0.004 to 2.0, a compound represented by chemical formula 2 above, the hindered phenolic antioxidant, and a compound represented by chemical formula 3 above.

4. The additive according to claim 1, wherein the hindered phenolic antioxidant is a compound containing two or more hydroxyl groups.

5. The additive according to claim 4, wherein the hindered phenolic antioxidant comprises a compound represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, R1 and R2 are each hydroxyl groups, and R3 is -H, a C1 to C12 straight-chain alkyl group, or a C3 to C12 branched-chain alkyl group.

6. The additive according to claim 5, wherein the hindered phenolic antioxidant comprises a compound represented by the following chemical formula 1-1: [Chemical Formula 1-1] In the above chemical formula 1-1, R4, R5 and R6 are each independently -H or C1 to C3 straight-chain alkyl groups.

7. The additive according to claim 1, wherein the isocyanate compound comprises one or more selected from 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, isophthalimethylene diisocyanate, terephthalimethylene diisocyanate, and orthophthalimethylene diisocyanate.

8. A mixture of isocyanates comprising an isocyanate compound; and an additive for long-term storage of the isocyanate compound. The additives used for the long-term storage of isocyanate compounds include hindered phenolic antioxidants.

9. The isocyanate mixture according to claim 8, wherein the isocyanate mixture comprises the isocyanate compound and the additive for long-term storage of the isocyanate compound in a weight ratio of 1:0.001 to 0.

3.

10. The isocyanate mixture according to claim 9, wherein the additive comprises a compound represented by chemical formula 2, a hindered phenolic antioxidant, and a compound represented by chemical formula 3: [Chemical Formula 2] [Chemical Formula 3] In the above chemical formula 2, R7 is -H, a C1 to C12 straight-chain alkyl group, or a C3 to C12 branched alkyl group, and In the above chemical formula 3, R8 is -H, a C1 to C12 straight-chain alkyl group, or a C3 to C12 branched alkyl group.

11. The isocyanate mixture according to claim 10, wherein the additive comprises, in a weight ratio of 1:0.005 to 2.0:0.004 to 2.0, a compound represented by chemical formula 2 above, the hindered phenolic antioxidant, and a compound represented by chemical formula 3 above.

12. A method for storing isocyanate compounds, comprising: The first step is to mix the isocyanate compound with an additive for long-term storage of the isocyanate compound to prepare an isocyanate mixture. as well as The second step involves storing the isocyanate mixture under a nitrogen-purified atmosphere at a temperature of 20°C or lower and a humidity of 1% RH or lower. The additives used for the long-term storage of isocyanate compounds include hindered phenolic antioxidants.

13. The method of claim 12, wherein the second step involves storing the isocyanate mixture in a nitrogen-purged atmosphere at a temperature of 0°C to 20°C and a humidity of 0.0001%RH to 1%RH.

14. An optical lens comprising the isocyanate mixture of claim 8.

15. The optical lens of claim 14, wherein the optical lens has a haze of 0.3% or less.

16. A non-foaming resin comprising the isocyanate mixture of claim 8.

17. The non-foaming resin of claim 16, wherein the non-foaming resin is used in coatings, adhesives, sealants or elastomers.

Images