Xylylene diisocyanate composition and application thereof

Abstract

The invention relates to a xylylene diisocyanate composition and application thereof, the xylylene diisocyanate composition contains 1-500 ppm of methyl isocyanate phenol, the xylylene diisocyanate composition can be stably stored for more than 6 months under the condition that the xylylene diisocyanate composition is in contact with air every week, and meanwhile, an optical material prepared from the xylylene diisocyanate composition has good dyeing performance.

Description

Technical Field

[0001] The present invention relates to the technical field of isocyanates, in particular to a xylylene diisocyanate composition and application thereof in the field of optical materials. Background Art

[0002] Compared to optical materials composed of inorganic materials such as glass, plastic optical materials are lightweight, durable, and have excellent dyeability, making them widely used in applications such as eyeglass lenses and camera lenses. In recent years, there has been a growing demand for optical materials with excellent properties such as high transparency, high refractive index, high heat resistance, high impact resistance, and versatile dyeability.

[0003] Polythiourethanes, a class of optical materials, are widely used due to their excellent optical and mechanical properties. They are prepared by polymerizing polythiol compounds and isocyanates. Lenses produced from polythiourethanes exhibit high refractive index, lightweight, and high impact resistance, making them a future trend in lens development. Xylylenediisocyanate (XDI), a raw isocyanate used in the preparation of polythiourethanes, is typically synthesized from xylylenediamine via the phosgene method (see patent GB1194459A) and is widely used.

[0004] Although xylylenediisocyanate has many advantages, due to the high reactivity of its NCO group, it tends to turn yellow or self-polymerize during long-term storage, which may cause substandard quality when preparing optical materials and adversely affect their dyeing properties.

[0005] Currently, hindered phenols are representative isocyanate stabilizers. For example, U.S. Patent No. 3715381A discloses 2,6-di-tert-butyl-4-methylphenol (BHT) as a stabilizer, but its stabilizing effect on XDI is poor. U.S. Patent No. 5302749A reports that phenol has a good stabilizing effect on XDI, but phenol is easily oxidized and discolored. Opening the barrel of XDI and exposing it to air during use can easily cause the product color to increase.

[0006] Therefore, stabilizers suitable for XDI still need to be developed, and the raw materials and processes of optical materials need to be controlled to ensure that the prepared optical materials have good performance. Summary of the Invention

[0007] In response to the shortcomings of the prior art, the present invention provides a xylylenediisocyanate composition and its application in optical materials. The xylylenediisocyanate composition contains 1-500 ppm of isocyanatomethylphenol and exhibits excellent storage stability. Furthermore, optical materials prepared using the xylylenediisocyanate composition exhibit good dyeing properties.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] The present invention provides a xylylene diisocyanate composition. The xylylene diisocyanate composition comprises xylylene diisocyanate and 1-500 ppm of isocyanatomethylphenol. The structure of the isocyanatomethylphenol is shown in formula (1).

[0010]

[0011] Preferably, the isocyanatomethylphenol comprises any one or a combination of at least two of the following compounds:

[0012]

[0013] Preferably, isocyanatomethylphenol can be prepared and purified from hydroxybenzylamine using a one-step phosgenation method well known to those skilled in the art, and then directly added to the product to achieve the desired content. Alternatively, it can be directly produced by adding a corresponding amount of an amine precursor prior to phosgenation of the isocyanate and then phosgenating it. However, for process stability reasons, the present invention adopts a method in which the isocyanatomethylphenol is first prepared and then directly added.

[0014] In a specific embodiment, phosgene can be introduced into a chlorobenzene solution containing hydroxybenzylamine to carry out a phosgenation reaction, and the product can be purified after the reaction is completed.

[0015] During the storage of XDI, due to the strong reactivity of its NCO group, it tends to turn yellow or self-polymerize when stored for a long time. In particular, when it comes into contact with air, it reacts with water in the air to form urea, the structural formula of which is as follows:

[0016]

[0017] In the technical solution of the present invention, since the xylylenediisocyanate composition contains isocyanatomethylphenol, it can combine with NCO to reduce the reactivity of NCO, thereby allowing the isocyanate to be stored stably for a long time.

[0018] Preferably, the urea content in the xylylenediisocyanate composition of the present invention is 0-2 wt %, preferably 0-0.2 wt %, of the composition.

[0019] Preferably, the xylylene diisocyanate includes any one or a combination of at least two of 1,2-xylylene diisocyanate (o-xylylene diisocyanate, o-XDI), 1,3-xylylene diisocyanate (m-xylylene diisocyanate, m-XDI) or 1,4-xylylene diisocyanate (p-xylylene diisocyanate, p-XDI), preferably 1,3-xylylene diisocyanate and / or 1,4-xylylene diisocyanate, more preferably 1,3-xylylene diisocyanate.

[0020] A second object of the present invention is to provide a method for preparing an optical material, wherein the optical material is prepared by polymerizing the xylylene diisocyanate composition described in the first object with a polythiol compound.

[0021] Preferably, the polythiol compound refers to a compound containing at least two thiol groups; such as aliphatic polythiol compounds, aromatic polythiol compounds, aromatic polythiol compounds containing sulfur atoms in addition to thiol groups, aliphatic polythiol compounds containing sulfur atoms and ester bonds in addition to thiol groups, aliphatic polythiol compounds containing sulfur atoms in addition to thiol groups, and their esters of thioglycolic acid and thiopropionic acid, etc.

[0022] Preferably, the polythiol compound is selected from the following:

[0023] Aliphatic polythiol compounds such as methanedithiol, 1,6-hexanedithiol, 1,2,3-propanetrithiol, 2,2-dimethylpropane-1,3-dithiol, 2,3-dimercapto-1-propanol (3-mercaptopropionate), diethylene glycol bis(2-mercaptoacetate), 2,2-bis(mercaptomethyl)-1,3-propanedithiol, ethylene glycol bis(3-mercaptopropionate), trimethylolpropane bis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), and tetrakis(mercaptomethyl)methane;

[0024] Aromatic polythiol compounds such as 1,2-dimercaptobenzene, 1,3,5-tris(mercaptoethyl)benzene, phenylmethane-1,1-dithiol, and 2,4-di(p-mercaptophenyl)pentane;

[0025] Aromatic polythiol compounds containing sulfur atoms other than mercapto groups, such as 1,2-bis(mercaptoethylthio)benzene, 1,3-bis(mercaptoethylthio)benzene, 1,4-bis(mercaptoethylthio)benzene, 1,2,3-tris(mercaptomethylthio)benzene, 1,2,4-tris(mercaptomethylthio)benzene, 1,3,5-tris(mercaptomethylthio)benzene, 1,2,3-tris(mercaptoethylthio)benzene, 1,2,4-tris(mercaptoethylthio)benzene, 1,3,5-tris(mercaptoethylthio)benzene, and alkylates thereof;

[0026] Aliphatic polythiol compounds containing a sulfur atom other than a mercapto group, such as bis(mercaptomethyl) sulfide, bis(mercaptomethylthio)methane, 2,3-dithio(2-mercapto)-1-propanethiol, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, bis(mercaptomethyl)-3,6,9-trithia-1,11-undecanedithiol, and bis(mercaptopropyl) disulfide, and their thioglycolic acid and mercaptopropionic acid esters;

[0027] Other aliphatic polythiol compounds containing sulfur atoms and ester bonds in addition to mercapto groups, such as bis(2-mercaptoacetate) of hydroxymethyl sulfide, bis(3-mercaptopropionate) of 2-mercaptoethyl ether, bis(2-mercaptoacetate) of 1,4-dithiadiol, bis(2-mercaptoethyl)-4,4-dithiodibutyrate, bis(2,3-dimercaptopropyl)thiodiacetate, bis(2,3-dimercaptopropyl)thiodipropionate, bis(2,3-dimercaptopropyl)dithiodiacetate, and bis(2,3-dimercaptopropyl)dithiodipropionate;

[0028] Heterocyclic compounds containing sulfur atoms other than mercapto groups, such as 3,4-thiophenedithiol and 2,5-dimercapto-1,3,4-thiadiazole;

[0029] Compounds containing a hydroxyl group other than a mercapto group, such as 2-mercaptoethanol, 1-hydroxy-4-mercaptocyclohexane, 4-mercaptophenol, 3,4-dimercapto-2-propanol, pentaerythritol tris(3-mercaptopropionate), and 1-hydroxyethylthio-3-mercaptoethylthiobenzene;

[0030] 1,1,3,3-Tetrakis(mercaptomethylthio)propane, 1,1,5,5-tetrakis(mercaptomethylthio)-3-thiapentane, 2,5-bis(4,4-bis(mercaptomethylthio)-2-thiabutyl)-1,4-dithiane, 4,6-bis{4-(6-mercaptomethylthio)-1,3-dithianylthio}-1,3-dithiane, 3-{2-(1,3-dithiacyclobutyl)}methyl-7,9-bis(mercaptomethylthio)-1, Compounds having a dithioacetal or dithioketal skeleton, such as 11-dimercapto-2,4,6,10-tetrathiaundecane, 4-{4-(5-mercaptomethylthio-1,3-dithiolanyl)thio}-5-[1-{2-(1,3-dithiocyclobutyl)}-3-mercapto-2-thiapropylthio]-1,3-dithiolane, and oligomers thereof;

[0031] Compounds having a trithioorthoformate skeleton, such as tris(mercaptomethylthio)methane, 2,4,6-tris(mercaptomethylthio)-1,3,5-trithiol, 2-(2,3-dimercaptopropylthio)-1,3-dithiolane, tris(4,4-bis(mercaptomethylthio)-3-thiabutyl)methane, 2,4,6-tris(3,3-bis(mercaptomethylthio)-2-thiapropyl)-1,3,5-trithiol, tetrakis(3,3-bis(mercaptomethylthio)-2-thiapropyl)methane, and oligomers thereof;

[0032] Compounds having a tetrathioorthocarbonate skeleton, such as 3,3'-bis(mercaptomethylthio)-1,5-dimercapto-2,4-dithiolane, 2,2'-bis(mercaptomethylthio)-1,3-dithiocyclopentane, 2,7-bis(mercaptomethyl)-1,4,5,9-tetrathiaspiro[4,4]nonane, 3,9-dimercapto-1,5,7,11-tetrathiaspiro[5,5]undecane, and oligomers thereof.

[0033] However, the polythiol compound is not limited to the compounds listed above. In addition, the compounds listed above may be used alone or in combination of two or more.

[0034] Furthermore, the polythiol compound is particularly preferably one or more of 2,3-dithio(2-mercapto)-1-propanethiol, bis(mercaptomethyl)-3,6,9-trithia-1,11-undecanedithiol, pentaerythritol tetrakis(3-mercaptopropionate), 1,1,3,3-tetrakis(mercaptomethylthio)propane and 2-mercaptoethanol.

[0035] Preferably, the isocyanate composition and the polythiol compound are used in a ratio such that the molar ratio of isocyanate (-NCO) / thiol (-SH) is (0.8-1.5):1.

[0036] Preferably, the preparation method of the optical material is carried out in the presence of a polymerization catalyst, preferably an organotin compound, such as dialkyltin halides such as dibutyltin dichloride and dimethyltin dichloride, and dialkyltin dicarboxylates such as dimethyltin diacetate, dibutyltin dioctoate, and dibutyltin dilaurate. The polymerization catalyst is added in an amount of 0.01% to 2.0% based on the total mass of the isocyanate composition and the polythiol compound, calculated based on the total mass of the catalyst used.

[0037] In addition, in the method for preparing the optical material, various auxiliary agents such as chain extenders, crosslinkers, light stabilizers, ultraviolet absorbers, antioxidants, oil-soluble dyes, fillers, and release agents may be optionally added depending on the purpose.

[0038] The optical material is usually manufactured by injection molding. In a specific embodiment, the polythiol compound and the xylylene diisocyanate composition are mixed, and a suitable auxiliary agent is optionally added.

[0039] In a specific embodiment, the mixed solution is degassed in a vacuum and then injected into an injection mold for an optical material. The mixture is typically heated according to a temperature ramp from 20-40°C to 120-140°C for 20-40 hours to polymerize and cure. The optical material is then demolded.

[0040] A third object of the present invention is to provide applications of the optical materials prepared by the above method, including plastic lens materials, automobile lampshade materials, transparent roof materials, lens materials for smartphones or tablets, etc.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] By adding 1-500 ppm of methyl isocyanate phenol to the xylylenediisocyanate composition provided by the present invention, the xylylenediisocyanate composition can be stably stored for more than 6 months under the condition that the container used is opened and exposed to air for 2 minutes per week. The optical material prepared has good dyeing performance, with a visible light transmittance of less than 40% after dyeing for 20 minutes and a visible light transmittance of less than 30% after dyeing for 40 minutes. DETAILED DESCRIPTION

[0043] The present invention is further described below with reference to the embodiments, but the present invention is not limited thereto.

[0044] (1) Raw material preparation

[0045] Methyl isocyanate phenol was synthesized according to the following synthetic route:

[0046]

[0047] Phosgene was introduced into a mixed solution of 246.3 mg (2.0 mmol) of 3-hydroxybenzylamine and 7.0 mL of chlorobenzene, and the reaction was continued at 120°C. The reaction was stopped when the reaction solution became clear. After cooling to room temperature, the chlorobenzene was distilled off to obtain a concentrated solution, yielding 163.9 mg (1.1 mmol) of 3-(isocyanatomethyl)phenol.

[0048] When preparing 2-(isocyanatomethyl)phenol or 4-(isocyanatomethyl)phenol, the corresponding raw materials 2-hydroxybenzylamine or 4-hydroxybenzylamine are used and synthesized in the same manner as described above.

[0049] use 1 H-NMR (400 MHz, CDCl3), 13The obtained isocyanatomethylphenol was analyzed by C-NMR (100 MHz, CDCl 3 ).

[0050] 1 H-NMR (400MHz, CDCl3) δ9.29 (s, 1H), 7.00 (t, 1H), 6.92 (dt, 4H), 6.85 (dt, 1H), 6.70 (t, 1H), 4.57 (s, 2H).

[0051] 13 C-NMR (100MHz, CDCl3) δ156.9, 140.3, 130.0, 125.0, 120.5, 114.7, 112.9, 54.9.

[0052] (2) Determination method of relevant tests in the present invention

[0053] 1. Content of methyl isocyanate phenol

[0054] First, using 99 mol% pure isocyanatomethylphenol synthesized as described above as a standard substance, gas chromatography analysis was performed under the following conditions, and a calibration curve was prepared from the area values ​​of the resulting gas chromatogram (external standard method). It should be noted that the retention time of isocyanatomethylphenol is approximately 15.3 minutes.

[0055] Instrument: Agilent 7890; chromatographic column: DB-200 (30 m × 0.25 mm × 0.25 μm); injection volume: 0.5 μL; split ratio: 1 / 30; inlet temperature: 260°C; column flow rate: 1.0 mL / min; temperature program: 50°C for 2 min, then increase the temperature to 80°C at 5°C / min, then increase the temperature to 270°C at 15°C / min and hold for 15 min; FID detector temperature: 280°C; hydrogen flow rate: 30 mL / min, air flow rate: 400 mL / min.

[0056] 2. Urea content

[0057] The urea in the xylylenediisocyanate composition was qualitatively and quantitatively analyzed by liquid chromatography.

[0058] Instrument: Agilent 1260; chromatographic column: Agilent Extend C18 RRHD 2.1×100mm 1.8μm; column temperature: 40℃; flow rate: 0.2mL / min; mobile phase: A: pure water, B: pure acetonitrile; injection volume: 20μL; detection wavelength: 210nm.

[0059] 3. The color number is measured by Lovibond Nessleriser 2250.

[0060] 4. Dyeing Performance Evaluation: Lenses were placed in a dyeing apparatus (a custom-made stainless steel barrel with a built-in temperature-controlled heating tube, containing the dye solution) for varying soak times (20 minutes and 40 minutes). The quality and uniformity of the dyeing were assessed manually using a parallel reflected light source. The depth of the dyeing was assessed using visible light transmittance measured with a haze meter (Haze-Gard Plus). Lower transmittance indicates better dyeing performance.

[0061] Add methyl isocyanate phenol to 1,3-xylylenediisocyanate in the amounts shown in Table 1. Store the mixture in a 1000 mL aluminum bottle, with the mixture accounting for 95% of the volume, under nitrogen at 20°C. Open the bottle to air once every week for 2 minutes, measure the color, and visually inspect for turbidity.

[0062] The preparation and testing methods of optical materials (plastic lens materials) are as follows:

[0063] 52g of the aforementioned 1,3-xylylenediisocyanate, 0.015g of dibutyltin dichloride as a catalyst, 0.10g of acidic phosphate (Stepan, trade name Zelec UN), and 0.05g of UV absorber UV-329 (Aladdin) were mixed and dissolved at 25°C. Then, 48g of 2,3-dithio(2-mercapto)-1-propanethiol was added and mixed to form a homogeneous mixture (polymerizable composition). This homogeneous mixture was degassed at 600 Pa for 1 hour and then filtered through a 1μm PTFE (polytetrafluoroethylene) filter. The mixture was then injected into a lens injection mold consisting of a 75mm diameter 4D glass mold and tape. This injection mold was placed in an oven and maintained at 40°C for 2 hours. The temperature was then raised to 50°C over 4 hours and maintained for 2 hours. The temperature was then raised to 60°C over 3 hours and maintained for 2 hours. The temperature was then raised to 70°C over 3 hours and held for 2 hours. The temperature was then raised to 100°C over 3 hours and then raised to 130°C over 1 hour and held for 2 hours. After polymerization, the injection mold was removed from the oven and demolded to yield a lens. The resulting lens was then annealed at 120°C for 3 hours. The lens was then placed in a dyeing vat for dyeing, using different soaking times (20 minutes and 40 minutes).

[0064] The conditions and results of each embodiment and comparative example are shown in Table 1.

[0065] Table 1 Conditions and results of Examples 1-5 and Comparative Examples 1-6

[0066]

[0067] The above data demonstrate that the addition of 1-500 ppm of methylisocyanatephenol to xylylenediisocyanate improves the stability of the xylylenediisocyanate composition, allowing it to be stored for over six months with weekly exposure to air. Furthermore, optical materials prepared using this isocyanate composition exhibit excellent dyeing properties, with visible light transmittances of <40% after 20 minutes of dyeing and <30% after 40 minutes of dyeing. The XDI composition provided by the present invention has promising application prospects in various optical materials.

[0068] The applicant states that the present invention is intended to illustrate the detailed methods of the present invention through the above-described embodiments, but the present invention is not limited to the above-described detailed methods, that is, it does not mean that the present invention must rely on the above-described detailed methods in order to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for various raw materials in the products of the present invention, addition of auxiliary ingredients, and selection of specific methods, etc., are all within the scope of protection and disclosure of the present invention.

Claims

1. A xylylene diisocyanate composition, characterized in that The xylylene diisocyanate composition comprises xylylene diisocyanate and 1-500 ppm of isocyanate methyl phenol, wherein the isocyanate methyl phenol is represented by formula (1):

2. The xylylene diisocyanate composition according to claim 1, wherein The xylylene diisocyanate includes any one or a combination of at least two of 1,2-xylylene diisocyanate, 1,3-xylylene diisocyanate, and 1,4-xylylene diisocyanate, preferably 1,3-xylylene diisocyanate and / or 1,4-xylylene diisocyanate, and more preferably 1,3-xylylene diisocyanate.

3. The xylylene diisocyanate composition according to claim 1, wherein The composition further comprises 0-2 wt %, preferably 0-0.2 wt % of urea based on the weight of the composition, wherein the urea is represented by formula (2):

4. The xylylene diisocyanate composition according to claim 1, wherein The compound represented by formula (1) includes any one or a combination of at least two of the following compounds:

5. A method for preparing an optical material, characterized in that: The optical material is prepared by polymerizing the xylylene diisocyanate composition according to any one of claims 1 to 4 and a polythiol compound.

6. The preparation method according to claim 5, characterized in that The dosage ratio of the xylylenediisocyanate composition and the polythiol compound is such that the molar ratio of isocyanate-NCO / thiol-SH is (0.8-1.5):

1.

7. The preparation method according to claim 5, characterized in that The preparation method also includes a polymerization catalyst, which is a dialkyl tin halide or dialkyl tin dicarboxylate compound, preferably dibutyltin dichloride, dimethyltin dichloride, dimethyltin diacetate, dibutyltin dioctoate, or dibutyltin dilaurate.

8. The preparation method according to claim 7, characterized in that The polymerization catalyst is added in an amount of 0.01% to 2.0% based on the total mass of the xylylene diisocyanate composition and the polythiol compound.

9. Applications of the optical material prepared by the optical material preparation method according to claim 5 include plastic lens materials, automobile lampshade materials, transparent roof materials, and lens materials for smartphones or tablets.

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