Hydrophobic high-temperature optical acrylic copolymer

Abstract

The present invention relates to acrylic copolymers and terpolymers incorporating high Tg hydrophobic (meth)acrylates that have high thermal stability and excellent optical properties. These copolymers are optically transparent, providing copolymers with Tg values ​​between 115 and 140°C along with sufficiently high molecular weights. The copolymers have been found to exhibit high heat resistance, high optical transmittance, low haze, low moisture absorption, excellent environmental stability, excellent high-temperature thermal stability, and excellent mechanical properties, along with excellent UV resistance. The copolymers or terpolymers can be used to form lighting tubes, thin-walled parts, optical lenses, extruded films, (co)extruded sheets / profiles, thermoformable sheets, cast sheets, composites, and the like.

Description

Technical Field

[0001] The present invention relates to acrylic copolymers and terpolymers incorporated with high-Tg hydrophobic (meth) acrylates and derivatives having high thermal stability and excellent optical properties. These copolymers are optically transparent and provide copolymers having a Tg of 115 to 150 °C with a sufficiently large molecular weight. This copolymer has been found to exhibit excellent UV resistance, high heat resistance, high light transmittance, low haze, low hygroscopicity, excellent environmental stability, excellent high-temperature thermal stability, and excellent mechanical properties. This copolymer or terpolymer can be used to form lighting tubes, thin-walled parts, optical lenses, extruded films, (co) extruded sheets / profiles, thermoformable sheets, cast sheets, composite materials, and the like.

Background Art

[0002] Thermoplastic polymers and copolymers, particularly (meth) acrylic polymers, have excellent characteristics such as transparency, mechanical properties, and processability, and are widely used in various fields such as automotive parts, electrical parts, industrial parts, optical materials, various parts of household electrical appliances, decorative parts, and sundries.

[0003] High-Tg acrylic polymers are useful in applications that require high optical transparency and high heat resistance, such as automotive front inner lenses, thin-walled parts, lighting tubes, optical protection / phase difference films for electronic devices, solar panels / films, household electrical appliances, and composite materials. The market for high-temperature acrylic copolymers in automotive LED front inner lenses and thin-walled parts is expected to increase rapidly. In addition, high-temperature acrylic films are also used in LED / OLED displays.

[0004] High-Tg acrylic copolymers such as methyl methacrylate / methacrylic acid copolymers are described in US2018-0362688.

[0005] US 10,043,930 describes high Tg acrylic copolymers using various high Tg comonomers for use in the front sheets of solar cells.

[0006] The main problems with standard acrylic copolymers and products are that they cannot pass long-term environmental stability tests such as the 85°C / 85%RH test required for automotive front inner lenses, solar panels, and new optical films for electronic devices. Most high Tg monomers such as methacrylic acid are hydrophilic, and their copolymers do not have moisture resistance.

[0007] The inventors have surprisingly solved this problem and produced a material that can pass environmental stability tests while maintaining high Tg and high optical transparency. The novel copolymer contains a high Tg hydrophobic monomer to increase the hydrophobicity of the copolymer while maintaining high Tg and high molecular weight. The resulting high molecular weight, high Tg, and high optical property copolymer is useful in many applications that require high temperature and / or high humidity environments.

[0008] Specifically, tert-butylcyclohexyl (meth)acrylate and 3,3,5-trimethylcyclohexyl (meth)acrylate, which are hydrophobic comonomers having a specific cis / trans ratio range, were found to reduce water absorption and increase hydrophobicity when copolymerized with pMMA. In addition, high Tg and / or Vicat temperature and high molecular weight were obtained. Films, sheets, and articles produced using this hydrophobic copolymer exhibited a light transmittance of over 91% and a haze of less than 2.5%. This copolymer may contain additional monomer units to make it a terpolymer, tetrapolymer, etc. Summary of the Invention

[0009] In a first aspect, the present invention relates to a high-Tg optically transparent hydrophobic acrylic copolymer composition comprising a high-Tg copolymer polymerized from 0.1 to 20 weight percent of monomer units selected from tert-butylcyclohexyl methacrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, and mixtures thereof; 50 to 80 weight percent of methyl methacrylate monomer units; and 0 to 49.9 weight percent of optional other monomer units copolymerizable with methyl methacrylate. The copolymer formed has a Tg of 115°C to 150°C, preferably 116°C to 140°C, more preferably 120°C to 130°C.

[0010] In a second aspect of the present invention, the high-Tg optically transparent hydrophobic acrylic copolymer composition has a trans / cis ratio of 30 / 70 to 85 / 15, more preferably 40 / 60 to 80 / 20, most preferably 50 / 50 to 75 / 25 in the tert-butylcyclohexyl methacrylate monomer unit and / or the 3,3,5-trimethylcyclohexyl (meth)acrylate monomer unit.

[0011] In a third aspect of the present invention, any of the high-Tg optically transparent hydrophobic acrylic copolymers of the above-described aspects comprises 0.01 to 25 weight percent of a high-Tg comonomer and other optional monomers. These optional monomers are selected from methacrylic acid, acrylic acid, itaconic acid, alpha-methylstyrene, maleic anhydride, maleimide, isobornyl methacrylate, norbornyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, acrylamide and methacrylamide, or mixtures thereof, and in particular is 0.1 to 5 weight percent of methacrylic acid.

[0012] In a fourth aspect of the present invention, any of the high-Tg optically transparent hydrophobic acrylic copolymer compositions of the above-described aspects may further comprise 50 to 3500 ppm of an antioxidant based on the weight of the copolymer solids.

[0013] In a fifth aspect of the present invention, any of the high-Tg optically transparent hydrophobic acrylic copolymer compositions of the foregoing aspects has a weight average molecular weight of from 55,000 g / mol to 250,000 g / mol, preferably from 75,000 g / mol to 200,000 g / mol, more preferably greater than 90,000 g / mol up to 200,000 g / mol.

[0014] In a sixth aspect of the present invention, any of the high-Tg optically transparent hydrophobic acrylic copolymer compositions of the foregoing aspects has a TWLT of at least 89%, preferably at least 91%, more preferably at least 92%; and an optical haze of less than 5%, preferably less than 3%, most preferably less than 2% as measured on a 3.2 mm thick sheet specimen using ASTM method D1003.

[0015] In a seventh aspect of the present invention, any of the high-Tg optically transparent hydrophobic acrylic copolymer compositions of any of the other aspects has a refractive index of from 1.47 to 1.50 at a wavelength of 589 nm.

[0016] In an eighth aspect of the present invention, any of the high-Tg optically transparent hydrophobic acrylic copolymer compositions of any of the foregoing aspects is a blend of the high-Tg transparent hydrophobic acrylic copolymer composition and one or more compatible polymers, and the high-Tg optically transparent hydrophobic acrylic copolymer composition is present in the blend at 5 to 95 weight percent, preferably 5 to 75 weight percent, more preferably 10 to 60 weight percent of the total polymer solids.

[0017] In a ninth aspect of the present invention, an article comprises any of the high-Tg optically transparent hydrophobic acrylic copolymer compositions of any of the other aspects. The article is a lighting tube, a thin-walled part, an optical lens, an extruded film, a (co)extruded sheet or profile, a thermoformable sheet, a cast sheet, a composite material, an LED / OLED optical component, a coextruded profile used in construction and building, or a reflective sign.

Mode for Carrying Out the Invention

[0018] "Copolymer" is used to mean a polymer having two or more different monomer units including the copolymer, and polymers having three or more different monomers such as terpolymers and tetrapolymers. "Polymer" is used to mean both homopolymers and copolymers. The polymer may be linear, branched, star-shaped, comb-shaped, block, or any other structure. The polymer may be uniform or non-uniform and may have a gradient distribution of comonomer units. All references cited are incorporated herein by reference. As used herein, unless otherwise indicated, percent means weight percent. The molecular weight is the weight average molecular weight measured by GPC. If some crosslinking is included in the polymer and GPC cannot be applied due to the insoluble polymer fraction, the molecular weight of the soluble fraction / gel fraction, or the soluble fraction after extraction from the gel is used.

[0019] As used herein, "hydrophobic" means that a 25 weight percent solution of the copolymer dissolved in toluene, when heated to 65 °C with stirring to form an opaque and viscous gel and then cooled to room temperature (23 °C), is optically transparent with a certain degree of soft gel. When heated to 65 °C, the viscous "solution" becomes opaque and at the same time physical gelation occurs throughout the "solution", resulting in a viscous jelly-like material due to the phase separation of the hydrophilic copolymer in a hydrophobic solvent (such as toluene) at high temperature (65 °C). In addition, this is a physically reversible process.

[0020] As used herein, "(meth)acrylic" or "(meth)acrylate" means both acrylate and methacrylate.

[0021] In one embodiment, the hydrophobic copolymer of the present invention passes the 85 °C / 85% RH test.

[0022] The present invention relates to a copolymer of methyl methacrylate and a specific hydrophobic high-Tg comonomer, where the "high-Tg monomer" refers to a monomer that produces a polymer having a Tg above 116°C, preferably above 120°C, more preferably above 130°C when polymerized. Examples of useful hydrophobic high-Tg monomers include, but are not limited to, tert-butylcyclohexyl methacrylate as a specific blend range of trans / cis isomers, and 3,3,5-trimethylcyclohexyl (meth)acrylate, and blends of these isomers.

[0023] Tert-butylcyclohexyl methacrylate The structural formula of tert-butylcyclohexyl (meth)acrylate is as follows: JPEG0007708670000001.jpg81170Tert-butylcyclohexyl methacrylate Tert-butylcyclohexyl acrylate

[0024] The monomer is a mixture of cis and trans forms with a trans / cis ratio of 30 / 70 to 85 / 15, preferably 40 / 60 to 80 / 20, more preferably 50 / 50 to 75 / 25.

[0025] The amount of tert-butylcyclohexyl (meth)acrylate in the final copolymer is usually in the range of 0.2 to 20 weight percent, and more preferably, 0.5 to 10 weight percent of tert-butylcyclohexyl methacrylate is used in the copolymer. As little as 1 weight percent, and even 0.5 weight percent of tert-butylcyclohexyl methacrylate has been found to result in a hydrophobic copolymer. The Tg of the copolymer of the present invention is 116°C to 140°C.

[0026] 3,3,5-Trimethylcyclohexyl (meth)acrylate The structural formula of 3,3,5-trimethylcyclohexyl (meth)acrylate is as follows:

[0027] The monomer is a mixture of cis-type and trans-type.

[0028] The amount of 3,3,5-trimethylcyclohexyl (meth)acrylate in the final copolymer is usually in the range of 0.2 to 20 weight percent, more preferably, 0.5 to 10 weight percent of tert-butylcyclohexyl methacrylate is used in the copolymer. It has been found that even 1 weight percent, and further 0.5 weight percent of tert-butylcyclohexyl methacrylate results in a hydrophobic copolymer. The Tg of the copolymer of the present invention is 116 °C to 135 °C. JPEG0007708670000002.jpg831703,3,5-trimethylcyclohexyl methacrylate 3,3,5-trimethylcyclohexyl acrylate

[0029] The amount of tert-butylcyclohexyl methacrylate or 3,3,5-trimethylcyclohexyl methacrylate in the final copolymer is usually in the range of 0.2 to 20 weight percent, more preferably 0.5 to 10 weight percent, based on the total of the monomer units in the copolymer. It has been found that even 1 weight percent, and further 0.5 weight percent of tert-butylcyclohexyl methacrylate results in a hydrophobic copolymer. The Tg of the copolymer of the present invention is 116 °C to 140 °C.

[0030] Acrylic monomer, MMA One or more hydrophobic high-Tg monomers are copolymerized with one or more other monomers. In a preferred embodiment of the present invention, the copolymer comprises at least 50 weight percent, preferably at least 70 weight percent, more preferably at least 80 weight percent of methyl methacrylate monomer units constituting the copolymer.

[0031] In addition to a hydrophobic high-Tg monomer and methyl methacrylate, the copolymer of the present invention may contain 0 to 49.5 weight percent of other acrylate and methacrylate monomers or other ethylenically unsaturated monomers (including, but not limited to, styrene, alpha-methylstyrene, acrylonitrile), and a small amount of a crosslinking agent may also be present in the monomer mixture. Suitable acrylate comonomers and methacrylate comonomers include, but are not limited to, methyl acrylate, ethyl acrylate and ethyl methacrylate, butyl acrylate and butyl methacrylate, isooctyl methacrylate and isooctyl acrylate, lauryl acrylate and lauryl methacrylate, stearyl acrylate and stearyl methacrylate, isobornyl acrylate and isobornyl methacrylate, methoxyethyl acrylate and methoxy methacrylate, 2-ethoxyethyl acrylate and 2-ethoxyethyl methacrylate, and dimethylaminoethyl acrylate and dimethylaminoethyl methacrylate monomers. (Meth)acrylic acids such as methacrylic acid and acrylic acid may be useful in the monomer mixture. In addition to the carboxyl functional group, other functional groups such as epoxy (such as glycidyl methacrylate), hydroxyl, and anhydride functional groups can be added to the high molecular weight acrylic processing aid via functional comonomers. The functional monomer units (monomer units having a functional group) can be present up to 70 weight percent, preferably up to 50 weight percent, of the acrylic polymer.

[0032] In a preferred embodiment, the acrylic copolymer has a high Tg exceeding 115°C, more preferably exceeding 120°C, exceeding 125°C, exceeding 130°C, exceeding 135°C, and even more preferably exceeding 140°C. In addition to tert-butylcyclohexyl methacrylate and 3,3,5-trimethylcyclohexyl (meth)acrylate, optionally other high-Tg monomers may be present in an amount of 0 to 25 wt%, more preferably 0 to 10 wt%. The other high-Tg monomers may have hydrophilic, hydrophobic, or neutral properties, and examples thereof include, but are not limited to, methacrylic acid, acrylic acid, itaconic acid, alpha-methylstyrene, maleic anhydride, maleimide, isobornyl methacrylate, norbornyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, acrylamide, and methacrylamide.

[0033] In one embodiment, it has been found that the hydrophobic effect of tert-butylcyclohexyl methacrylate and / or 3,3,5-trimethylcyclohexyl (meth)acrylate is strong enough to overcome the hydrophilic effect of the hydrophilic comonomer used at a low level, resulting in an overall hydrophobic copolymer.

[0034] Synthesis process The copolymer of the present invention can be obtained by melt polymerization such as, but not limited to, solution polymerization, emulsion polymerization, and suspension polymerization.

[0035] It has been found that the processing conditions can have a significant impact on the Tg of the copolymer. Generally, solution polymerization of the copolymer has been found to result in a higher level of syndiotacticity (about 60%) and a higher Tg (about 50%) than the copolymer produced by the melt process. In a laboratory solution process carried out at about 65 - 75°C, the Tg of the copolymer was found to be about 124°C. In a melt polymer process in a pilot plant carried out at about 160°C, the Tg was found to be about 120°C. Without being bound by a particular theory, the difference in copolymer Tg is thought to be related to the percentage of syndiotacticity that increases with lower processing temperatures. Further, the toluene used in solution polymerization can have different chemical environments.

[0036] Additive The copolymers of the present invention can be blended with typical additives used in thermoplastics. These include, but are not limited to, fillers, surface modifiers, antioxidants, UV screens, processing aids, fibers, lubricants, heat stabilizers, flame retardants, synergists, pigments, and other colorants.

[0037] Impact modifiers can be added to the composition, but they will have an adverse effect on optical transparency. When used, they need to have a refractive index that matches the matrix, which means that the refractive index difference from the matrix is less than 0.02, preferably less than 0.01. Preferably, the composition does not contain an impact modifier.

[0038] Other polymer additives include polycarbonate, polyurethane, polysulfone, polyamide, polyolefin, copolymers and terpolymers based on these polymers, including linear, branched, block, and graft polymer structures. Examples of matting agents include, but are not limited to, crosslinked polymer particles of various shapes. The amount of filler and additive contained in the polymer composition of each layer can vary from about 0.01% to about 70% of the total weight of the polymer, additive, and filler. Usually, amounts of about 5% to about 45%, about 10% to about 40% are included.

[0039] Antioxidant In one embodiment, a selected antioxidant can be used to improve the thermal stability of the resin at high temperatures, such as 255 - 275 °C, and reduce yellowing at high temperatures. The amount of antioxidant incorporated into the final resin formulation is in an amount of about 50 ppm to 3500 ppm, preferably about 100 ppm to about 2500 ppm, based on the total weight of the composition. Non-limiting examples of useful antioxidants include sterically hindered phenols, organic phosphite esters, hindered amine light stabilizers (HALS), benzotriazoles, triazines, benzophenones, and cyanoacrylates.

[0040] Properties The novel hydrophobic high-temperature acrylic-based material of the present invention is designed to meet the requirements of high light transmission in the visible wavelength region, very low haze, high heat resistance, low water / moisture absorption, excellent environmental stability, and excellent mechanical properties, optionally together with the requirement of excellent UV resistance. Therefore, it is particularly useful in applications with specific high temperatures and high optical transparency.

[0041] The Tg of the copolymer is usually in the range of 115 °C to 150 °C, preferably 116 °C to 140 °C, more preferably 120 °C to 130 °C.

[0042] The weight average molecular weight of the acrylic copolymer is over 55,000 g / mol, preferably over 75,000 g / mol, more preferably over 90,000 g / mol, still more preferably over 100,000 g / mol. The maximum molecular weight is about 250,000 g / mol, more preferably about 200,000 g / mol.

[0043] The hydrophobic high Tg copolymers of the present invention, including the copolymers, terpolymers, and tetrapolymers of the present invention, have a refractive index of 1.47 to 1.50 at a wavelength of 589 nm.

[0044] The copolymer provides low moisture adsorption and enhanced hydrophobicity.

[0045] The copolymer of the present invention has excellent optical properties with at least 89%, preferably at least 91%, more preferably at least 92% TWLT and less than 5%, preferably less than 3%, most preferably less than 2% optical haze.

[0046] In addition to the above-described properties, the copolymer of the present invention has excellent UV resistance, excellent environmental stability, and excellent mechanical properties.

[0047] Blends of the high Tg copolymers of the present invention with other polymers, particularly acrylic polymers, are contemplated in the present invention. The high Tg copolymers or terpolymers of the present invention (refractive index 1.47 to 1.50) are optically and physically compatible with many typical optical acrylic copolymers (refractive index about 1.49) in their mixtures and / or combinations by melt processing / solution blending. The copolymers of the present invention are typically blended with 5 to 95 weight percent, preferably 5 to 75 weight percent, more preferably 10 to 60 weight percent of other acrylic resins based on the total polymer solids.

[0048] Blends in any ratio with other compatible polymers are also contemplated in the present invention. Compatible polymers particularly useful for blending include, but are not limited to, other poly(methyl methacrylate) copolymers such as pMMA-EA and PMMA-MA, poly(styrene-acrylonitrile, SAN), polyvinylidene fluoride, copolymers of vinylidene fluoride and hexafluoropropene, and polylactic acid.

[0049] Use The copolymer of the present invention is thermoplastic and can be easily molded into sheets, films, lighting tubes, and lenses.

[0050] Due to its excellent thermal stability, high molecular weight, moisture resistance, and excellent optical properties, the copolymer of the present invention is particularly useful for lighting tubes, thin-walled parts, optical lenses, extruded films, (co)extruded sheets / profiles, thermoformed sheets, cast sheets, composite materials, etc.

[0051] The high-temperature acrylic film of the present invention can be used in LED / OLED displays. When cost-effective OLED technology is widely used to replace LED / LCD technology, the number of polarizers for OLEDs can be reduced.

[0052] In this specification, embodiments have been described in a form that enables writing a clear and concise specification, but it is intended and will be understood that the embodiments can be variously combined or separated without departing from the present invention. For example, it will be understood that all the preferred features described herein are applicable to all aspects of the present invention described herein.

Examples

[0053] Test method: A. Measurement of melt flow rate (MFR): To measure the melt flow rate of the polymer, an Instron Ceast MF30 apparatus was used. While setting the weight of the load cell to 3.8 kg, the temperature of the die was controlled at 230°C. Tg Pellets dried at a temperature of about 20 °C below for 8 hours were used.

[0054] B. Gel Permeation Chromatography (GPC): The molecular weight of the polymer was measured using Waters Alliance 2695 and Waters Differential Refractometer 2410. The columns were based on two PL Gel mixed C columns and a guard column (inner diameter 7.8 mm × 30 cm, 5 μm). THF (HPLC grade) was selected as the solvent. The temperature was controlled at 35 °C. For calibration, 10 poly(methyl methacrylate) standards in the range of M p (peak molecular weight) from 550 to 1,677,000 g / mol were used.

[0055] C. Differential Scanning Calorimetry (DSC): The glass transition temperature of the acrylic polymer was measured using a TA Instruments Q2000 DSC in N2 at a heating rate of 10 °C / min during the second heating. The sample was first heated to 170 °C at a heating rate of 10 °C / min using the first heating, and then cooled to 0 °C at a cooling rate of 10 °C / min. The sample weight was controlled at 5 - 10 mg.

[0056] D. Thermogravimetric Analysis (TGA): The thermal decomposition temperature of the acrylic polymer was measured using a TA Instruments Q5000 TGA in N2 at a heating rate of 10 °C / min. The sample weight was controlled at 5 - 10 mg. The sample was pre-dried overnight in a vacuum oven at 100 °C.

[0057] E. Total Light Transmittance: The total light transmittance was measured in transmission mode from film and / or plate-shaped test piece samples using a Perkin Elmer Lambda 950 equipped with a 150 mm integrating sphere. The selected UV / Vis wavelength range was 200 nm - 800 nm in the UV / Vis region.

[0058] F. Haze: The optical haze of transparent film and / or plate-shaped test piece samples was measured using BYK HazeGard Plus based on ASTM method D1003.

[0059] G. Tensile Strength and Elongation: The tensile strength, modulus of elasticity, and elongation of the tensile bar were evaluated using an Instron Model 4202 at a crosshead speed of 5 mm / min after pre-conditioning at 23 °C for 48 hours in accordance with ASTM D638. The tensile specimens were 6 inches in length and 0.50 inches in width. The thickness of the samples was 0.125 inches.

[0060] H. Refractive Index: The refractive index of the polymer film was measured at three different wavelengths of 402 nm, 518 nm, and 636.5 nm using an optical prism coupler, Metricon 2010 from Metricon Inc. The refractive index was calculated at the selected wavelength of 589 nm.

[0061] I. NMR: Samples were 13 prepared by dissolving approximately 200 mg of the pellet in about 4 ml of CDCl3 in a separate 10 mm NMR tube for 13C NMR. 1 The 1H spectrum was acquired at 25 °C using a 5 mm 1H / 1 19F / 19 13C TXO probe on a Bruker AV III HD 500 (11.07 T) spectrometer before and after derivatization of MAA. 13 The 13C spectrum was acquired at 50 °C using a 10 mm BBO probe on a Bruker AV 400 (9.4 T). 13 The 13C spectrum was acquired at 50 °C using a 10 mm BBO probe on a Bruker AV 400 (9.4 T).

[0062] J. Vicat Softening Temperature: Samples were tested on an Instron HV6M under external forces of 10 N and 50 N using ASTM method D1525. The heating rate of the samples was controlled at a rate of 50 °C / hour. The injection-molded samples were annealed at approximately 20 °C below the Tg value for 16 hours and stored in a desiccator oven before testing.

[0063] K. Water Absorption: The injection-molded samples were immersed in a deionized water bath (23 °C) using ASTM method D570. The size of the plate-shaped test piece samples was molded to 45 mm (width) × 67 mm (length) × 3.2 mm (thickness). The water absorption value was measured based on the weight increase when the sample surface was cleaned with a dry tissue.

[0064] L. 85 °C / 85% RH Test: Using a Thermotron SE-1000-6-6 environmental oven with deionized water in the humidifier, the injection-molded samples were held at 85 °C / 85% RH. The size of the tensile bar samples was molded to 12.5 mm (width) × 165 mm (length) × 3.2 mm (thickness). Defects such as cracks and crack lines were visually inspected during the 85 °C / 85% RH test.

[0065] pMMA-co-tert-butylcyclohexyl methacrylate Example 1: (pMMA copolymer containing 3.7% tert-butylcyclohexyl methacrylate). This example shows the preparation of a high molecular weight copolymer of methyl methacrylate and tert-butylcyclohexyl methacrylate having a trans / cis isomer ratio of 51% / 49%. 96.30 parts of methyl methacrylate and 3.70 parts of tert-butylcyclohexyl methacrylate were placed into a reaction vessel containing 300 parts of toluene at about 23 °C with a mechanical stirring speed of 380 rpm. As an initiator, AIBN (from Aldrich) was used in an amount of 0.337 parts. The polymerization reaction was carried out at 68 - 70 °C for 7 hours. When the conversion rate reached >60%, the residual monomer was removed by precipitation in methanol (MeOH, ×20 times). Then, the solid polymer powder was dissolved in acetone at 25% solids content, and the polymer solution was precipitated again in sufficient MeOH. The reprecipitated white powder samples were dried in a vacuum oven at 180 °C and 210 °C for 8 hours each. The melt flow rate of the polymer was measured to be 4.1 g / 10 min at 230 °C and 3.8 kg. The refractive index of the obtained polymer was measured to be 1.491 at 589 nm.

[0066] 1 Using 1H NMR, it was confirmed that the obtained polymer had a composition of pMMA / tert-butylcyclohexyl methacrylate (96.5 / 3.5 w / w). The syndiotacticity of the copolymer was 13 determined to be 60% from the chemical shift of 44.5 ppm using 13C NMR, and the isotacticity and atacticity were measured to be 4% and 36% from 45.5 ppm and 45.0 ppm, respectively. The glass transition temperature of the resin was measured to be 125 °C in N2 using DSC at a heating rate of 10 °C / min. The weight average molecular weight Mw of the resin was measured to be 88,000 g / mol using GPC, and the Mw / Mn (polydispersity) value was 1.9. The light transmittance from a 120-μm cast film was measured to be 92.2% at 560 nm using Lambda 950 equipped with a 150-mm integrating sphere, and the haze was measured to be 0.5% using a haze meter (BYK's Haze Gard Plus).

[0067] Example 2 (pMMA copolymer containing 5.1% tert-butylcyclohexyl methacrylate, Tg = about 128 °C). This example shows the preparation of a high molecular weight copolymer of methyl methacrylate and tert-butylcyclohexyl methacrylate having a trans / cis isomer ratio of 51% / 49%. 94.9 parts of methyl methacrylate and 5.10 parts of tert-butylcyclohexyl methacrylate were placed into a reaction vessel containing 300 parts of toluene at about 23 °C with a mechanical stirring speed of 360 rpm. As initiators, AIBN (from Aldrich) and Luperox® 26 (from Arkema) were used in amounts of 0.337 parts and 0.0 parts, respectively. The polymerization reaction was carried out at 65-67 °C for 7 hours. When the conversion reached >60%, the residual monomer was removed by precipitation in MeOH (×20 times). The solid polymer powder was then dissolved in acetone at 25 wt% solids, and the polymer solution was precipitated again in sufficient MeOH. The reprecipitated white powder sample was dried in a vacuum oven at 180 °C and 210 °C for 8 hours each. The melt flow rate of the polymer was measured to be 2.7 g / 10 min at 230 °C, 3.8 kg. The refractive index of the obtained polymer was measured to be 1.490 at 589 nm.

[0068] 1 Using 1H NMR, it was confirmed that the obtained polymer had a composition of pMMA / tert-butylcyclohexyl methacrylate (95.7 / 4.3 w / w). The syndiotacticity of the copolymer was 13Using \(^{13}\)C NMR, it was determined to be 60% from the chemical shift of 44.5 ppm, and the isotacticity and atacticity were measured to be 4% and 36% from 45.5 ppm and 45.0 ppm, respectively. The glass transition temperature of the resin was measured to be 128 °C in N₂ using DSC at a heating rate of 10 °C / min. The weight average molecular weight Mw of the resin was measured to be 100,000 g / mol using GPC, and the Mw / Mn (polydispersity) value was 2.1. The light transmittance from a 100-μm cast film was measured to be 92.3% at 560 nm using Lambda 950 equipped with a 150-mm integrating sphere, and the haze was measured to be 0.5% using a haze meter (BYK's Haze Gard Plus).

[0069] Example 3 (pMMA terpolymer containing 6.1% tert-butylcyclohexyl methacrylate and 4.6% MAA). This example shows the preparation of a high molecular weight copolymer of methyl methacrylate and tert-butylcyclohexyl methacrylate (51% trans / 49% cis isomer ratio). 89.3 parts of methyl methacrylate, 4.6 parts of methacrylic acid, and 6.1 parts of tert-butylcyclohexyl methacrylate were placed into a reaction vessel containing 300 parts of toluene at about 23 °C with a mechanical stirring speed of 360 rpm. Further, as initiators, AIBN (Aldrich) and Luperox® 26 (from Arkema) were used in amounts of 0.350 part and 0 part, respectively. The polymerization reaction was carried out at 65 - 68 °C for 7 hours. When the conversion reached >60%, the residual monomer was removed by precipitation in MeOH (×20 times). Then, the solid polymer powder was dissolved in acetone at 25 wt% solids, and the polymer solution was precipitated again in sufficient MeOH. The reprecipitated white powder sample was dried in a vacuum oven at 180 °C and 210 °C for 8 hours each. The melt flow rate of the polymer was measured to be 1.6 g / 10 min at 230 °C and 3.8 kg. The refractive index of the obtained polymer was measured to be 1.491 at 589 nm.

[0070] 1Using \(^1H\) NMR, it was confirmed that the obtained polymer had a composition of pMMA / tert-butylcyclohexyl methacrylate / methacrylic acid (91.3 / 4.9 / 3.8 w / w / w). The syndiotacticity of the copolymer was determined to be 60% from the chemical shift of 44.5 ppm using \(^{13}C\) NMR, and the isotacticity and atacticity were measured to be 4% and 36% from 45.5 ppm and 45.0 ppm, respectively. The glass transition temperature of the resin was measured to be 135 °C in \(N_2\) using DSC at a heating rate of 10 °C / min. The weight average molecular weight \(M_w\) of the resin was measured to be 110,000 g / mol using GPC, and the \(M_w / M_n\) (polydispersity) value was 2.0. The light transmittance from a 125-μm cast film was measured to be 92.2% at 560 nm using Lambda 950 equipped with a 150-mm integrating sphere, and the haze was measured to be 0.5% using a haze meter (BYK's Haze Gard Plus). 13

[0071] Example 4 (pMMA copolymer containing 1.0% tert-butylcyclohexyl methacrylate, Tg = about 120 °C). This example shows the preparation of a high molecular weight copolymer of methyl methacrylate and tert-butylcyclohexyl methacrylate (73% trans / 27% cis isomer ratio). 9866 parts of methyl methacrylate and 100 parts of tert-butylcyclohexyl methacrylate were placed into a reaction vessel at about 0 °C under N2 at a mechanical stirring speed of 100 rpm. Further, Luperox® 531 (from Arkema) was used in an amount of 1.6 parts as an initiator, and 32 parts of n-dodecyl mercaptan (n-DDM, from Aldrich) was used together with 1.0 part of di-tert-dodecyl disulfide (DtDDS, from Arkema) as a chain transfer agent. The polymerization reaction was carried out at 160 °C for 7 hours. When the conversion reached about 50%, the residual monomer was removed from the vent system. The resulting polymer was passed through a single-screw extruder at a die temperature of 240 °C while the barrel temperature was between 230 and 250 °C. The melt stream was passed through a water bath before pelletization. Then, the polymer was pelletized into resin pellets with a length of 3 - 4 mm and dried in a desiccator oven at 100 °C for 8 hours. The melt flow rate of the polymer was measured to be 2.1 g / 10 min at 230 °C and 3.8 kg. The refractive index of the resulting polymer was measured to be 1.491 at 589 nm.

[0072] 1 Using 1H NMR, it was confirmed that the resulting polymer had a composition of pMMA / tert-butylcyclohexyl methacrylate (99.1 / 0.9 w / w). The syndiotacticity of the copolymer was 13Using 13C NMR, the isotacticity and atacticity were determined to be 50% from the chemical shift of 44.5 ppm, and measured to be 8% and 42% from 45.5 ppm and 45.0 ppm, respectively. The glass transition temperature of the resin was measured to be 120 °C in N2 using DSC at a heating rate of 10 °C / min, and the Vicat temperature was detected to be 120 °C at 10 N. The weight-average molecular weight Mw of the resin was measured to be 105,000 g / mol using GPC, and the Mw / Mn (polydispersity) value was 2.0. The light transmittance from a 3.2-mm plate specimen was measured to be 92.1% at 560 nm using Lambda 950 equipped with a 150-mm integrating sphere, and the haze was measured to be 1.0% using a haze meter (BYK's Haze Gard Plus). The tensile modulus of the test sample was 3.2 GPa, the tensile strength was 78 MPa, and the tensile elongation was 9.5%.

[0073] Example 5 (pMMA copolymer containing 3.0% tert-butylcyclohexyl methacrylate, Tg = about 119 °C). This example shows the preparation of a high molecular weight copolymer of methyl methacrylate and tert-butylcyclohexyl methacrylate (73% trans / 27% cis isomer ratio). 9566 parts of methyl methacrylate and 300 parts of tert-butylcyclohexyl methacrylate were placed into a reaction vessel at about 0 °C under N2 at a mechanical stirring speed of 100 rpm. Further, Luperox® 531 (from Arkema) was used in an amount of 1.6 parts as an initiator, and 32 parts of n-dodecyl mercaptan (n-DDM, from Aldrich) was used together with 1.0 part of di-tert-dodecyl disulfide (DtDDS, from Arkema) as a chain transfer agent. The polymerization reaction was carried out at 160 °C for 7 hours. When the conversion reached about 50%, the residual monomer was removed from the vent system. The obtained polymer was passed through a single screw extruder at a die temperature of 245 °C while the barrel temperature was between 230 - 250 °C. The melt stream was passed through a water bath before pelletization. Then, the polymer was pelletized into resin pellets with a length of 3 - 4 mm and dried in a desiccator oven at 100 °C for 8 hours. The melt flow rate of the polymer was measured to be 2.7 g / 10 min at 230 °C and 3.8 kg. The refractive index of the obtained polymer was measured to be 1.491 at 589 nm.

[0074] 1 Using 1H NMR, it was confirmed that the obtained polymer had a composition of pMMA / tert-butylcyclohexyl methacrylate (97.2 / 2.8 w / w). The syndiotacticity of the copolymer was 1313C NMR was used to determine 50% from a chemical shift of 44.5 ppm, and the isotacticity and atacticity were measured at 8% and 42% from 45.5 ppm and 45.0 ppm, respectively. The glass transition temperature of the resin was measured at 119 °C in N2 using DSC at a heating rate of 10 °C / min, and the Vicat temperature was detected at 119 °C at 10 N. The weight average molecular weight Mw of the resin was measured at 105,000 g / mol using GPC, and the Mw / Mn (polydispersity) value was 2.0. The light transmittance from a 3.2 mm sheet specimen was measured at 92.0% at 560 nm using Lambda950 equipped with a 150 mm integrating sphere, and the haze was measured at 1.0% using a haze meter (BYK's Haze Gard Plus). The tensile modulus of the test sample was 3.1 GPa, the tensile strength was 70 MPa, and the tensile elongation was 9.2%.

[0075] Example 6 (pMMA copolymer containing 1.5% tert-butylcyclohexyl methacrylate and 4% MAA, Tg = about 123 °C). This example shows the preparation of a high molecular weight copolymer of methyl methacrylate and tert-butylcyclohexyl methacrylate (73% trans / 27% cis isomer ratio). 9416 parts of methyl methacrylate and 400 parts of MethAcrylic acid and 150 parts of tert-butylcyclohexyl methacrylate were placed into a reaction vessel at about 0 °C under N2 with a mechanical stirring speed of 100 rpm. Further, 1.6 parts of Luperox® 531 (from Arkema) was used as an initiator, and 32 parts of n-dodecyl mercaptan (n-DDM, from Aldrich) was used together with 1.0 part of di-tert-dodecyl disulfide (DtDDS, from Arkema) as a chain transfer agent. The polymerization reaction was carried out at 160 °C for 7 hours. When the conversion reached about 50%, the residual monomer was removed from the vent system. The obtained polymer was passed through a single-screw extruder at a die temperature of 240 °C while the barrel temperature was between 230 and 250 °C. The melt stream was passed through a water bath before pelletization. Thereafter, the polymer was pelletized into resin pellets with a length of 3 - 4 mm and dried in a desiccator oven at 100 °C for 8 hours. The melt flow rate of the polymer was measured to be 1.4 g / 10 min at 230 °C and 3.8 kg. The refractive index of the obtained polymer was measured to be 1.492 at 589 nm.

[0076] 1 Using 1H NMR, it was confirmed that the obtained polymer had a composition of pMMA / tert-butylcyclohexyl methacrylate / methacrylic acid (95.8 / 1.2 / 3.0 w / w). The syndiotacticity of the copolymer was 13Using \(^{13}\)C NMR, it was determined to be 50% from the chemical shift of 44.5 ppm, and the isotacticity and atacticity were measured to be 8% and 42% from 45.5 ppm and 45.0 ppm, respectively. The glass transition temperature of the resin was measured to be 123 °C in N₂ using DSC at a heating rate of 10 °C / min, and the Vicat temperature was detected to be 123 °C at 10 N. The weight-average molecular weight Mw of the resin was measured to be 105,000 g / mol using GPC, and the Mw / Mn (polydispersity) value was 2.0. The light transmittance from a 3.2 mm sheet specimen was measured to be 91.9% at 560 nm using a Lambda 950 equipped with a 150 mm integrating sphere, and the haze was measured to be 1.0% using a haze meter (BYK's Haze Gard Plus). The tensile modulus of the test sample was 3.3 GPa, the tensile strength was 75 MPa, and the tensile elongation was 9.6%.

[0077] Comparative Example 1 (pMMA copolymer containing 4.8% MAA, Tg = about 124 °C). This example shows the preparation of a high molecular weight copolymer containing 4.8% methacrylic acid. 9480 parts of methyl methacrylate and 480 parts of Methacrylic acid were placed into a reaction vessel at about 0 °C under N₂ with a mechanical stirring speed of 100 rpm. Further, Luperox® 531 (from Arkema) was used in an amount of 1.6 parts as an initiator, and 38 parts of n-dodecyl mercaptan (n-DDM, from Aldrich) was used together with 1.0 part of di-tert-dodecyl disulfide (DtDDS, from Arkema) as a chain transfer agent. The polymerization reaction was carried out at 160 °C for 7 hours. When the conversion reached about 50%, the residual monomer was removed from the vent system. The obtained polymer was passed through a single-screw extruder at a die temperature of 240 °C while the barrel temperature was between 230 - 250 °C. The melt flow was passed through a water bath before pelletization. Then, the polymer was pelletized into resin pellets with a length of 3 - 4 mm and dried in a desiccator oven at 100 °C for 8 hours. The melt flow rate of the polymer was measured to be 2.2 g / 10 min at 230 °C and 3.8 kg. The refractive index of the obtained polymer was measured to be 1.494 at 589 nm.

[0078] 1 Using \(^1H\) NMR, it was confirmed that the obtained polymer had a composition of pMMA / methacrylic acid (96.3 / 3.7 w / w). The syndiotacticity of the copolymer was determined to be 50% from the chemical shift of 44.5 ppm using \(^{13}C\) NMR, and the isotacticity and atacticity were measured to be 8% and 42% from 45.5 ppm and 45.0 ppm, respectively. The glass transition temperature of the resin was measured to be 124 °C in \(N_2\) using DSC at a heating rate of 10 °C / min, and the Vicat temperature was detected to be 121 °C at 10 N. The weight-average molecular weight \(M_w\) of the resin was measured to be 82,000 g / mol using GPC, and the \(M_w / M_n\) (polydispersity) value was 2.0. The light transmittance from a 3.2-mm plate specimen was measured to be 92.0% at 560 nm using Lambda 950 equipped with a 150-mm integrating sphere, and the haze was measured to be 1.0% using a haze meter (BYK's Haze Gard Plus). The tensile modulus of the test sample was 3.5 GPa, the tensile strength was 73 MPa, and the tensile elongation was 9.6%. 13 JPEG0007708670000003.jpg119170​

Claims

1. a) 0.1 to 20 weight percent of tert-butylcyclohexyl methacrylate monomer units; b) at least 80 weight percent of methyl methacrylate monomer units; c) other monomer units copolymerizable with methyl methacrylate; A high-Tg optically transparent hydrophobic acrylic copolymer composition comprising a high-Tg copolymer, wherein the total weight percentage of monomer units a), b) and c) is 100 weight percent, the copolymer has a Tg of 115°C to 150°C, preferably 116°C to 140°C, more preferably 120°C to 130°C, the other monomer units contain 0.01 to 10 weight percent of methacrylic acid, preferably 0.1 weight percent to 5 weight percent of methacrylic acid, based on the weight of the high-Tg copolymer, the other monomer units contain a high-Tg comonomer selected from the group consisting of methacrylic acid, acrylic acid, itaconic acid, alpha-methylstyrene, maleic anhydride, maleimide, isobornyl methacrylate, norbornyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, acrylamide and methacrylamide, and mixtures thereof, Composition.

2. The high-Tg optically transparent hydrophobic acrylic copolymer composition according to claim 1, wherein the tert-butylcyclohexyl methacrylate monomer units have a trans / cis ratio of 30 / 70 to 85 / 15, more preferably 40 / 60 to 80 / 20, most preferably 50 / 50 to 75 / 25.

3. The high-Tg optically transparent hydrophobic acrylic copolymer composition according to claim 1, further comprising 50 to 3500 ppm of an antioxidant based on the weight of the solid content of the copolymer.

4. The high-Tg optically transparent hydrophobic acrylic copolymer composition according to claim 1, wherein the copolymer has a weight average molecular weight of 55,000 g / mol to 250,000 g / mol, preferably 75,000 g / mol to 200,000 g / mol, more preferably more than 90,000 g / mol up to 200,000 g / mol.

5. The high-Tg optically transparent hydrophobic acrylic copolymer composition according to claim 1, having at least 89%, preferably at least 91%, more preferably at least 92% total light transmittance in the UV / Vis wavelength range of 200 nm to 800 nm in the UV / Vis region; and an optical haze of less than 5%, preferably less than 3%, most preferably less than 2% measured on a plate-shaped test piece with a thickness of 3.2 mm using ASTM method D1003.

6. The high-Tg optically transparent hydrophobic acrylic copolymer composition according to claim 1, wherein the copolymer has a refractive index of 1.47 to 1.50 at a wavelength of 589 nm.

7. The high-Tg optically transparent hydrophobic acrylic copolymer composition according to claim 1, further comprising 5 to 95 weight percent of one or more compatible polymers based on the total weight of the polymer solids.

8. An article comprising the high-Tg optically transparent hydrophobic acrylic copolymer composition according to claim 1, which is a lighting tube, a thin-walled component, an optical lens, an extruded film, a (co)extruded sheet or profile, a thermoformable sheet, a cast sheet, a composite material, an LED / OLED optical component, a coextruded profile used in architecture and construction, or a reflective sign.

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