Hydrophobic high heat optical acrylic copolymer

Abstract

The present invention relates to acrylic copolymers and terpolymers incorporating high Tg hydrophobic (meth)acrylates having high thermal stability and excellent optical properties. These copolymers are optically transparent and provide copolymers having a Tg of 115 - 140 °C and a sufficiently high molecular weight. It has been found that the copolymers exhibit high heat resistance, high light transmittance, low haze, low moisture uptake, excellent environmental stability, excellent high-temperature thermal stability and excellent mechanical properties, as well as 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, composite materials, etc.

Description

TECHNICAL FIELD

[0001] The present invention relates to acrylic copolymers, terpolymers and derivatives incorporating high Tg hydrophobic (meth)acrylates having high thermal stability and excellent optical properties. These copolymers are optically transparent and provide copolymers having a Tg of 115 - 150 °C and a sufficiently high molecular weight. It has been found that the copolymers exhibit high heat resistance, high light transmittance, low haze, low moisture uptake, excellent environmental stability, excellent high temperature thermal stability and excellent mechanical properties, as well as excellent UV resistance. The copolymers or terpolymers can be used to form lighting tubes, thin wall parts, optical lenses, extruded films, (co)extruded sheets / profiles, thermoformable sheets, cast sheets, composite materials, etc. BACKGROUND ART

[0002] Thermoplastic polymers and copolymers, especially (meth)acrylic polymers, have excellent properties 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 appliances, aesthetic parts, miscellaneous items, etc.

[0003] High Tg acrylic polymers can be used in applications requiring high optical transparency and high heat resistance, such as automotive front inner lenses, thin wall parts, lighting tubes, optical protection / delay films in electronic devices, solar panels / membranes, household appliances, composite materials, etc. The market for high heat acrylic copolymers used in automotive LED front inner lenses and thin wall parts is expected to grow rapidly. In addition, high heat acrylic films are also used in LED / OLED displays.

[0004] High Tg acrylic copolymers such as methyl methacrylate / methacrylic acid copolymers are described in US 2018 - 0362688.

[0005] US 10,043,930 describes high Tg acrylic copolymers using multiple high Tg comonomers for photovoltaic front plates.

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

[0007] The inventors have now surprisingly solved this problem and have produced materials that can pass environmental stability tests while maintaining a high Tg and high optical transparency. The novel copolymer contains hydrophobic monomers with a high Tg to increase the hydrophobicity of the copolymer while maintaining a high Tg and high molecular weight. The resulting high molecular weight, high Tg, high optical property copolymer can be used in many different applications that require high heat and / or humid environments.

[0008] Specifically, it has been found that the hydrophobic comonomers tert-butylcyclohexyl (meth)acrylate and 3,3,5-trimethylcyclohexyl (meth)acrylate having a specific cis / trans ratio range copolymerize with pMMA to reduce water absorption and enhance hydrophobicity. Additionally, a high Tg and / or Vicat temperature and high molecular weight are obtained. Films, sheets, and articles made from the hydrophobic copolymer exhibit a light transmittance of more than 91% and a haze of less than 2.5%. The copolymer may contain additional monomer units, making it a terpolymer, quaternary copolymer, etc. Summary of the Invention

[0009] In a first aspect, the present invention relates to a high Tg, optically transparent, hydrophobic acrylic copolymer composition containing a high Tg copolymer, the high Tg copolymer being polymerized from monomer units of: 0.1 wt% to 20 wt% of monomer units selected from tert-butylcyclohexyl methacrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, and mixtures thereof; and 50 wt% to 80 wt% of methyl methacrylate monomer units, with optionally 0 wt% to 49.9 wt% of other monomer units copolymerizable with methyl methacrylate. The resulting copolymer has a Tg of 115°C to 150°C, preferably 116°C to 140°C, and 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, and most preferably 50 / 50 to 75 / 25 in the tert-butylcyclohexyl methacrylate and / or 3,3,5-trimethylcyclohexyl (meth)acrylate monomer units.

[0011] In a third aspect of the present invention, the high Tg, optically transparent, hydrophobic acrylic copolymer of any of the above aspects contains one or more optional other monomers in an amount of 0.01 wt% to 25 wt% based on the high Tg comonomer. These optional monomers are selected from methacrylic acid, acrylic acid, itaconic acid, α-methylstyrene, maleic anhydride, maleimide, isobornyl methacrylate, norbornyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, acrylamide, and methacrylamide, or mixtures thereof, and especially 0.1 wt% to 5 wt% of methacrylic acid.

[0012] In a fourth aspect of the present invention, the high-Tg, optically transparent, hydrophobic acrylic copolymer composition of any of the foregoing aspects may further comprise an antioxidant in an amount of 50 ppm to 3500 ppm based on the weight of the copolymer solid.

[0013] In a fifth aspect of the present invention, the high-Tg, optically transparent, hydrophobic acrylic copolymer composition of any of the foregoing aspects 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 greater than 90,000 g / mol to 200,000 g / mol.

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

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

[0016] In an eighth aspect of the present invention, the high-Tg, optically transparent, hydrophobic acrylic copolymer composition 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, transparent, hydrophobic acrylic copolymer composition is present in the blend in an amount of 5 wt% to 95 wt%, preferably 5 wt% to 75 wt% and more preferably 10 wt% to 60 wt% of the total polymer solid.

[0017] In a ninth aspect of the present invention, an article contains the high-Tg, optically transparent, hydrophobic acrylic copolymer composition of any other aspect. 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 for building and construction or a reflective sign. Detailed Description

[0018] "Copolymer" is used to mean a polymer having two or more different monomer units, including copolymers, and polymers having three or more different monomers, such as terpolymers and quaterpolymers. "Polymer" is used to mean both homopolymers and copolymers. The polymer can be linear, branched, star-shaped, comb-shaped, block or any other structure. The polymer can be homogeneous, heterogeneous, and can have a gradient distribution of comonomer units. All cited references are incorporated herein by reference. As used herein, unless otherwise described, percentages shall mean weight percentages. The molecular weight is the weight-average molecular weight measured by GPC. In the case where the polymer contains some crosslinking 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 wt% solution of the copolymer in toluene forms an opaque viscous gel-gelatin when heated to 65 °C with stirring and then cooled to room temperature (23 °C), and is optically transparent together with some soft gels. After heating to 65 °C, physical gelation occurs throughout the "solution", and the viscous "solution" becomes opaque, resulting in the appearance of a viscous gel-like material due to the phase separation of the hydrophilic copolymer in a hydrophobic solvent (such as toluene) at a high temperature (65 °C). Additionally, this is a physically reversible process.

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

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

[0022] The present invention relates to a copolymer of methyl methacrylate and a specific hydrophobic high-Tg comonomer. "High-Tg monomer" means a monomer that, when polymerized, produces a polymer having a Tg greater than 116 °C, preferably greater than 120 °C, and more preferably greater than 130 °C. 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 its isomer blend.

[0023] tert-Butylcyclohexyl methacrylate

[0024] (Meth)acrylate of tert-butylcyclohexyl has the following structural formula:

[0025]

[0026] The monomer is a mixture of cis and trans forms, with a trans / cis ratio between 30 / 70 and 85 / 15, preferably between 40 / 60 and 80 / 20 and more preferably between 50 / 50 and 75 / 25.

[0027] The level of tert-butylcyclohexyl (meth)acrylate in the final copolymer is generally in the range of 0.2 wt% to 20 wt% and more preferably 0.5 wt% to 10 wt% of the tert-butylcyclohexyl (meth)acrylate used in the copolymer. It has been found that as low as 1 wt% and even 0.5 wt% of tert-butylcyclohexyl (meth)acrylate provides a copolymer with hydrophobic properties. The Tg of the copolymer of the present invention is from 116 °C to 140 °C.

[0028] 3,3,5-Trimethylcyclohexyl (meth)acrylate

[0029] 3,3,5-Trimethylcyclohexyl (meth)acrylate has the following structural formula:

[0030] The monomer is a mixture of cis and trans forms.

[0031] The level of 3,3,5-trimethylcyclohexyl (meth)acrylate in the final copolymer is generally in the range of 0.2 wt% to 20 wt% and more preferably 0.5 wt% to 10 wt% of the tert-butylcyclohexyl (meth)acrylate used in the copolymer. It has been found that as low as 1 wt% and even 0.5 wt% of 3,3,5-trimethylcyclohexyl (meth)acrylate provides a copolymer with hydrophobic properties. The Tg of the copolymer of the present invention is from 116 °C to 135 °C.

[0032]

[0033] The level of tert-butylcyclohexyl (meth)acrylate or 3,3,5-trimethylcyclohexyl (meth)acrylate in the final copolymer is generally in the range of 0.2 wt% to 20 wt% and more preferably 0.5 wt% to 10 wt% based on the total monomer units in the copolymer. It has been found that as low as 1 wt% and even 0.5 wt% of tert-butylcyclohexyl (meth)acrylate provides a copolymer with hydrophobic properties. The Tg of the copolymer of the present invention is from 116 °C to 140 °C.

[0034] Acrylic monomer, MMA

[0035] 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 contains at least 50 wt% of methyl methacrylate monomer units, preferably at least 70 wt% and more preferably at least 80 wt% of methyl methacrylate monomer units, which constitute the copolymer.

[0036] In addition to one or more hydrophobic high Tg monomers and methyl methacrylate, the copolymers of the present invention may also contain from 0 wt% to 49.5 wt% of other acrylate and methacrylate monomers or other ethylenically unsaturated monomers, including but not limited to styrene, α-methylstyrene, acrylonitrile, and low levels of crosslinkers may also be present in the monomer mixture. Suitable acrylate 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 methoxyethyl 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 used in the monomer mixture. In addition to carboxyl functional groups, other functional groups may also be added to the high molecular weight acrylic processing aids through functional comonomers, including epoxy groups such as glycidyl methacrylate, hydroxyl groups and anhydride functional groups. Functional monomer units (monomer units having functional groups) may be present in the acrylic polymer up to 70 wt%, preferably up to 50 wt%.

[0037] In a preferred embodiment, the acrylic copolymer has a high Tg greater than 115 °C, more preferably greater than 120 °C, greater than 125 °C, greater than 130 °C, greater than 135 °C and even greater than 140 °C. In addition to tert-butylcyclohexyl methacrylate and 3,3,5-trimethylcyclohexyl (meth)acrylate, other high Tg monomers may also optionally be present at levels from 0 wt% to 25 wt% and more preferably from 0 wt% to 10 wt%. Other high Tg monomers may be hydrophilic, hydrophobic or have neutral characteristics and include but are not limited to methacrylic acid, acrylic acid, itaconic acid, α-methylstyrene, maleic anhydride, maleimide, isobornyl methacrylate, norbornyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, acrylamide and methacrylamide.

[0038] 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 comonomers used at lower levels, resulting in an all-hydrophobic copolymer.

[0039] Synthesis method

[0040] The copolymers of the present invention are obtained by melt polymerization, including but not limited to solution polymerization, emulsion polymerization and suspension polymerization.

[0041] It was found that process conditions have a significant effect on the Tg of the copolymer. Generally, it was found that solution polymerization of the copolymer produces a higher level of syndiotacticity (-60%) and a higher Tg compared to the syndiotacticity (-50%) and Tg produced in the melt process. In a laboratory solution process operating at about 65 - 75 °C, the Tg of the copolymer was found to be about 124 °C. In a pilot plant melt polymerization process operating at about 160 °C, the Tg was found to be about 120 °C. While not limited to any particular theory, it is believed that the difference in the copolymer Tg is related to the percentage of syndiotacticity, with a higher percentage of syndiotacticity at lower process temperatures. Additionally, the toluene used in solution polymerization may have a different chemical environment.

[0042] Additives

[0043] The copolymers of the present invention can be blended with typical additives used in thermoplastics. These include but are not limited to fillers, surface modifying additives, antioxidants, UV blockers, processing aids, fibers, lubricants, heat stabilizers, flame retardants, synergists, pigments, and other colorants.

[0044] Although impact modifiers can be added to the composition, they can have a negative impact on optical transparency. If used, their refractive index needs to match that of the matrix, which means that the refractive index difference from the matrix is less than 0.02, and preferably less than 0.01. Preferably, the composition does not contain impact modifiers.

[0045] Other polymer additives can include polycarbonates, polyurethanes, polysulfones, polyamides, polyolefins, including copolymers and terpolymers based on these polymers, and including linear, branched, block, and graft polymer structures. Examples of matting agents include but are not limited to cross-linked polymer particles of various geometries. The amount of fillers and additives included in the polymer composition of each layer can vary between about 0.01% and about 70% of the combined weight of the polymer, additive, and filler. Typically, amounts include about 5% to about 45%, about 10% to about 40%.

[0046] Antioxidant

[0047] In one embodiment, the 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. Based on the total weight of the composition, the loading level of the antioxidant in the final resin formulation is -50 ppm to 3500 ppm, preferably about 100 ppm to about 2500 ppm. Non-limiting examples of useful antioxidants include sterically hindered phenols, organophosphites, hindered amine light stabilizers (HALS), benzotriazoles, triazines, benzophenones, and cyanoacrylates.

[0048] Properties

[0049] The novel hydrophobic high-Tg acrylic materials of the present invention are designed to meet the requirements of high light transmittance, extremely low haze, high heat resistance, low water / moisture uptake, excellent environmental stability, and excellent mechanical properties in the visible light wavelength region, and optionally have excellent UV resistance, making them particularly useful for certain high-heat, high-optical transparency applications.

[0050] The Tg of the copolymer is generally in the range of 115 °C to 150 °C, preferably 116 °C to 140 °C, and more preferably 120 °C to 130 °C.

[0051] The weight-average molecular weight of the acrylic copolymer is greater than 55,000 g / mol, preferably greater than 75,000 g / mol, more preferably greater than 90,000 g / mol, and even more preferably greater than 100,000 g / mol. The maximum molecular weight is about 250,000 g / mol and more preferably about 200,000 g / mol.

[0052] 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 - 1.50 at a wavelength of 589 nm.

[0053] The copolymer provides low hygroscopicity and enhanced hydrophobicity.

[0054] The copolymer of the present invention has excellent optical properties, having a TWLT of at least 89%, preferably at least 91%, and more preferably at least 92%; and an optical haze of less than 5%, preferably less than 3%, and most preferably less than 2%.

[0055] In addition to the above properties, the copolymer of the present invention also has excellent environmental stability, excellent mechanical properties, and excellent UV resistance.

[0056] Blends of the high-Tg copolymers of the present invention with other polymers and especially acrylic polymers are contemplated by the present invention. The high-Tg copolymers or terpolymers of the present invention (refractive index 1.47 - 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 will generally be blended with other acrylic resins at 5 wt% to 95 wt%, preferably 5 wt% to 75 wt%, and more preferably 10 wt% to 60 wt% of the total polymer solids.

[0057] The present invention also contemplates blends with other compatible polymers in all ratios. Compatible polymers particularly useful for blends 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 hexafluoropropylene, and polylactic acid.

[0058] use

[0059] The copolymers of the present invention are thermoplastic and can be easily formed into sheets, films, light pipes and lenses.

[0060] Excellent thermal stability, high molecular weight, moisture resistance and excellent optical properties make the copolymers of the present invention particularly useful for forming lighting tubes, thin-walled parts, optical lenses, extruded films, (co)extruded sheets / profiles, thermoformable sheets, cast sheets, composite materials, etc.

[0061] The high heat acrylic film of the present invention can be used in LED / OLED displays. If cost-effective OLED technology is widely used to replace LED / LCD technology, the number of optical polarizers used for OLED can be reduced.

[0062] In this specification, embodiments have been described in a manner that enables a clear and concise description to be written, but it is intended and should be understood that the embodiments may be combined or separated in various ways without departing from the present invention. For example, it should be understood that all preferred features described herein apply to all aspects of the invention described herein.

[0063] Example

[0064] Test methods:

[0065] A. Melt flow rate (MFR) measurement : An Instron Ceast MF30 device was used for polymer melt flow rate measurement. The mold temperature was controlled at 230°C and the loading unit weight was 3.8 kg. The dried pellets were heated below T g Use at close to 20℃ for 8 hours.

[0066] B. Gel permeation chromatography (GPC) : Polymer molecular weight measurements were performed using a Waters Alliance 2695 and a Waters differential refractometer 2410. The columns were based on two PL Gel mixed C columns and one guard column (7.8 mm i.d. x 30 cm, 5 μm). THF (HPLC grade) was selected as the solvent. The temperature was controlled at 35°C. Ten poly(methyl methacrylate) standards were used in the calibration, with M p (peak molecular weight) in the range of 550 to 1,677,000 g / mole.

[0067] C. Differential scanning calorimetry (DSC) : During the second heating, the glass transition temperature of the acrylic polymer was measured using a TA Instruments Q2000 DSC at a heating rate of 10 °C / min in N 2 . The first heating was used to heat the sample to 170 °C at a heating rate of 10 °C / min, and then the sample was cooled to 0 °C at a cooling rate of 10 °C / min. The sample weight was controlled at 5 - 10 mg.

[0068] D. Thermogravimetry (TGA): The thermal decomposition temperature of the acrylic polymer was measured using a TA Instruments Q5000 TGA at a heating rate of 10 °C / min in N 2 . The sample weight was controlled at 5 - 10 mg. The sample was pre-dried overnight in a vacuum oven at 100 °C.

[0069] E. Total light transmittance The total transmittance was measured from film and / or plaque samples in transmission mode using a Perkin Elmer Lambda950 with a 150 mm integrating sphere. The selected UV / Vis wavelength range was from 200 nm to 800 nm in the UV / Vis region.

[0070] F. Haze : The optical haze of transparent film and / or plaque samples was measured using a BYK HazeGard Plus according to ASTM method D1003.

[0071] G. Tensile strength and elongation: After pretreatment at 23 °C / 48 h, the tensile strength, modulus, and elongation of the tensile bar were evaluated using an Instron 4202 at a crosshead speed of 5 mm / min using ASTM D638 method. The tensile length was 6 inches, while the width was 0.50 inches. The sample thickness was 0.125 inches.

[0072] 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 Corporation, and the refractive index was calculated at the selected wavelength of 589 nm.

[0073] I. NMR : Samples were prepared by dissolving approximately 200 mg of the particles in approximately 4 ml of CDCL 13 in a separate 10 mm NMR tube for 3 C NMR. Before and after MAA derivatization, at 25 °C with 5 mm 1 H / 19 F / 13The 1H NMR spectra of CTXO were recorded on a Bruker AV III HD500 (11.07 T) spectrometer. The 13C NMR spectra were recorded on a Bruker AV400 (9.4 T) using a 10 mm BBO probe at 50 °C. 1 The 1H NMR spectra of CTXO were recorded on a Bruker AV III HD500 (11.07 T) spectrometer. The 13C NMR spectra were recorded on a Bruker AV400 (9.4 T) using a 10 mm BBO probe at 50 °C. 13 The 13C NMR spectra.

[0074] J. Vicat softening temperature : Samples were tested in an Instron HV6M at 10 N and 50 N external forces using ASTM D1525 method. The sample heating rate was controlled at 50 °C / hour. Injection molded samples were annealed at -20 °C below the Tg value for 16 hours and stored in a desiccator oven before testing.

[0075] K. Water absorption : Injection molded samples were immersed in a deionized water bath (23 °C) using ASTM method D570. The molded plaque sample size was 45 mm (width) × 67 mm (length) × 3.2 mm (thickness). The water absorption value was measured based on weight gain while cleaning the sample surface with a dry paper towel.

[0076] L. 85°C / 85% RH test: Injection molded samples were maintained at 85 °C / 85% RH using a Thermotron SE-1000-6-6 environmental oven with deionized water for the humidifier. The molded tensile bar size was 12.5 mm (width) × 165 mm (length) × 3.2 mm (thickness). During the 85 °C / 85% RH test, defects such as cracking and / or rupture lines were visually inspected.

[0077] pMMA-co-tert-butylcyclohexyl methacrylate

[0078] Example 1: (pMMA copolymer with 3.7% tert-butylcyclohexyl methacrylate).

[0079] This example demonstrates the preparation of a high molecular weight copolymer of methyl methacrylate and tert-butylcyclohexyl methacrylate (with a 51% trans / 49% cis isomer ratio). 96.30 parts of methyl methacrylate and 3.70 parts of tert-butylcyclohexyl methacrylate were charged into a reaction vessel containing 300 parts of toluene at a temperature close to 23 °C and a mechanical stirring speed of 380 rpm. AIBN (from Aldrich) was used as an initiator at a level of 0.337 parts. The polymerization reaction was carried out at 68 - 70 °C for 7 hours. When the conversion reached >60%, the residual monomers were removed by precipitation in methanol (MeOH, ×20 times). Then, the solid polymer powder was dissolved in acetone at a solid content of 25 wt.%, and the polymer solution was again precipitated in sufficient MeOH. The reprecipitated white powder sample was dried in a vacuum oven at 180 °C and 210 °C for 8 hours and 8 hours, respectively. The melt flow rate of the polymer was measured to be 4.1 g / 10 min at 3.8 kg at 230 °C. The refractive index of the resulting polymer was measured to be 1.491 at 589 nm.

[0080] Using 1 1H NMR confirmed that the resulting polymer had a composition of pMMA / tert-butylcyclohexyl methacrylate (96.5 / 3.5 w / w). Using 13 13C NMR determined the syndiotacticity of the copolymer to be 60% from the chemical shift at 44.5 ppm, while the isotacticity and atacticity were measured to be 4% and 36% from 45.5 ppm and 45.0 ppm, respectively. Using DSC in N 2 2 at a heating rate of 10 °C / min, the glass transition temperature of the resin was measured to be 125 °C. Using GPC, the weight-average molecular weight Mw of the resin was 88,000 g / mol, and the Mw / Mn (polydispersity) value was 1.9. Using a Lambda 950 with a 150 mm integrating sphere, the light transmittance of a 120 µm cast film was measured to be 92.2% at 560 nm, while the haze was measured to be 0.5% using a haze meter (Haze GardPlus from BYK).

[0081] Example 2 (pMMA copolymer containing 5.1% tert-butylcyclohexyl methacrylate, with Tg = approximately 128 °C). This example demonstrates the preparation of a high molecular weight copolymer of methyl methacrylate and tert-butylcyclohexyl methacrylate (with a 51% trans / 49% cis isomer ratio). 94.9 parts of methyl methacrylate and 5.10 parts of tert-butylcyclohexyl methacrylate were charged into a reaction vessel containing 300 parts of toluene at a temperature close to 23 °C and a mechanical stirring speed of 360 rpm. AIBN (from Aldrich) and 26 (from Arkema) was used as the initiator at levels 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 monomers were removed by precipitation in MeOH (×20 times). Then, the solid polymer powder was dissolved in acetone at a solid content of 25 wt.%, and the polymer solution was again precipitated in sufficient MeOH. The re-precipitated white powder samples were dried in a vacuum oven at 180 °C and 210 °C for 8 hours and 8 hours, respectively. The melt flow rate of the polymer was measured to be 2.7 g / 10 min at 3.8 kg at 230 °C. The refractive index of the resulting polymer was measured to be 1.490 at 589 nm.

[0082] was used 1 1H NMR confirmed that the resulting polymer had a composition of pMMA / tert-butylcyclohexyl methacrylate (95.7 / 4.3 w / w). was used 13 13C NMR determined the syndiotacticity of the copolymer to be 60% from the chemical shift at 44.5 ppm, while the isotacticity and atacticity were measured to be 4% and 36% from 45.5 ppm and 45.0 ppm, respectively. Using DSC in N 2 2 at a heating rate of 10 °C / min, the glass transition temperature of the resin was measured to be 128 °C. Using GPC, the weight-average molecular weight Mw of the resin was 100,000 g / mol, and the Mw / Mn (polydispersity) value was 2.1. Using a Lambda 950 with a 150 mm integrating sphere, the light transmittance from a 100 µm cast film was measured to be 92.3% at 560 nm, while the haze was measured to be 0.5% using a haze meter (Haze GardPlus from BYK).

[0083] Example 3 (pMMA terpolymer with 6.1% tert-butylcyclohexyl methacrylate and 4.6% MAA).

[0084] This example demonstrates the preparation of a high molecular weight copolymer of methyl methacrylate and tert-butylcyclohexyl methacrylate (with a 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 charged into a reaction vessel containing 300 parts of toluene at a temperature close to 23 °C and a mechanical stirring speed of 360 rpm. Additionally, AIBN (Aldrich) and 26 (from Arkema) was used as an initiator at levels of 0.350 parts and 0 parts, respectively. The polymerization reaction was carried out at 65 - 68 °C for 7 hours. When the conversion reached >60%, the residual monomers were removed by precipitation in MeOH (×20 times). Then, the solid polymer powder was dissolved in acetone at a solid content of 25 wt.%, and the polymer solution was again precipitated in sufficient MeOH. The re-precipitated white powder samples were dried in a vacuum oven at 180 °C and 210 °C for 8 hours and 8 hours, respectively. The melt flow rate of the polymer was measured at 3.8 kg at 230 °C to be 1.6 g / 10 min. The refractive index of the resulting polymer was measured at 589 nm to be 1.491.

[0085] Using 1 H NMR confirmed that the resulting polymer had a composition of pMMA / tert-butylcyclohexyl methacrylate / methacrylic acid (91.3 / 4.9 / 3.8 w / w / w). Using 13 C NMR, the syndiotacticity of the copolymer was determined to be 60% from the chemical shift at 44.5 ppm, while the isotacticity and atacticity were measured to be 4% and 36% from 45.5 ppm and 45.0 ppm, respectively. Using DSC, the glass transition temperature of the resin was measured to be 135 °C at a heating rate of 10 °C / min in N 2 2. The weight-average molecular weight Mw of the resin was measured to be 110,000 g / mol using GPC, and the Mw / Mn (polydispersity) value was 2.0. The light transmittance of a 125-μm cast film was measured to be 92.2% at 560 nm using a Lambda950 with a 150-mm integrating sphere, while the haze was measured to be 0.5% using a haze meter (Haze Gard Plus from BYK).

[0086] Example 4 (pMMA copolymer containing 1.0% tert-butylcyclohexyl methacrylate, with Tg = approximately 120 °C). This example demonstrates the preparation of a high-molecular-weight copolymer of methyl methacrylate and tert-butylcyclohexyl methacrylate (with a 73% trans / 27% cis isomer ratio). 9866 parts of methyl methacrylate and 100 parts of tert-butylcyclohexyl methacrylate were charged into a reaction vessel at approximately 0 °C under N 2 2 and with a mechanical stirring speed of 100 rpm. Additionally, 1.6 parts of 531 (from Arkema) was used as the initiator, while 32 parts of n-dodecyl mercaptan (n-DDM from Aldrich) together with 1.0 part of ditert-dodecyl disulfide (DtDDS from Arkema) were used as the chain transfer agents. The polymerization reaction was carried out at 160 °C for 7 hours. When the conversion reached about 50%, the residual monomers were removed through the exhaust system. The resulting polymer was passed through a single-screw extruder at a die temperature of 240 °C, while the barrel temperature was 230 - 250 °C. The melt flow passed through a water bath before pelletization. Then the polymer was pelletized into resin pellets 3 - 4 mm in length and dried in a dryer 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 under 3.8 kg. The refractive index of the resulting polymer was measured to be 1.491 at 589 nm.

[0087] was used 1 1H NMR confirmed that the resulting polymer had a composition of pMMA / tert-butylcyclohexyl methacrylate (99.1 / 0.9 w / w). was used 13 13C NMR determined the syndiotacticity of the copolymer to be 50% from the chemical shift at 44.5 ppm, while the isotacticity and atacticity were measured to be 8% and 42% from 45.5 ppm and 45.0 ppm. Using DSC in N 2 2, the glass transition temperature of the resin was measured to be 120 °C at a heating rate of 10 °C / min, while the Vicat temperature was detected to be 120 °C under 10 N. Using GPC, the weight-average molecular weight Mw of the resin was 105,000 g / mol, and the Mw / Mn (polydispersity) value was 2.0. Using a Lambda 950 with a 150 mm integrating sphere, the light transmittance from a 3.2 mm plaque was measured to be 92.1% at 560 nm, while the haze was measured to be 1.0% using a haze meter (Haze Gard Plus from BYK). The tensile modulus of the test sample was 3.2 GPa, while the tensile strength was 78 MPa, and the tensile elongation was 9.5%.

[0088] Example 5 (pMMA copolymer containing 3.0% tert-butylcyclohexyl methacrylate, with Tg = about 119 °C). This example demonstrates the preparation of a high molecular weight copolymer of methyl methacrylate and tert-butylcyclohexyl methacrylate (with a trans / cis isomer ratio of 73% / 27%). 9566 parts of methyl methacrylate and 300 parts of tert-butylcyclohexyl methacrylate were charged into a reaction vessel at a temperature close to 0 °C under N 2 2 and with a mechanical stirring speed of 100 rpm. Additionally, 1.6 parts of 531 (from Arkema) was used as the initiator, while 32 parts of n-dodecyl mercaptan (n-DDM from Aldrich) together with 1.0 part of ditert-dodecyl disulfide (DtDDS from Arkema) were used as the chain transfer agents. The polymerization reaction was carried out at 160 °C for 7 hours. When the conversion reached about 50%, the residual monomers were removed through the exhaust system. The resulting polymer was passed through a single-screw extruder at a die temperature of 245 °C, while the barrel temperature was 230 - 250 °C. The melt flow passed through a water bath before pelletization. Then the polymer was pelletized into resin pellets 3 - 4 mm in length and dried in a dryer 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 under 3.8 kg. The refractive index of the resulting polymer was measured to be 1.491 at 589 nm.

[0089] Use 1 1H NMR confirmed that the resulting polymer had a composition of pMMA / t-butylcyclohexyl methacrylate (97.2 / 2.8 w / w). The syndiotacticity of the copolymer was determined to be 50% from the chemical shift at 44.5 ppm using 13C NMR, while 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 119 °C at a heating rate of 10 °C / min in N 2 using DSC, while the Vicat temperature was detected to be 119 °C under 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 plaque was measured to be 92.0% at 560 nm using a Lambda 950 with a 150 mm integrating sphere, while the haze was measured to be 1.0% using a haze meter (Haze Gard Plus from BYK). The tensile modulus of the test sample was 3.1 GPa, while the tensile strength was 70 MPa, and the tensile elongation was 9.2%.

[0090] Example 6 (pMMA copolymer containing 1.5% t-butylcyclohexyl methacrylate and 4% MAA, with Tg = about 123 °C). This example demonstrates the preparation of a high molecular weight copolymer of methyl methacrylate and t-butylcyclohexyl methacrylate (with a 73% trans / 27% cis isomer ratio). 9416 parts of methyl methacrylate, 400 parts of methacrylic acid, and 150 parts of t-butylcyclohexyl methacrylate were charged into a reaction vessel at a temperature close to 0 °C under N 2 and a mechanical stirring speed of 100 rpm. Additionally, 1.6 parts of 531 (from Arkema) was used as an initiator, while 32 parts of n-dodecyl mercaptan (n-DDM from Aldrich) together with 1.0 part of ditert-dodecyl disulfide (DtDDS from Arkema) were used 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 through the exhaust system. The resulting polymer was passed through a single-screw extruder at a die temperature of 240 °C, while the barrel temperature was 230 - 250 °C. The melt flow passed through a water bath before pelletization. Then the polymer was pelletized into resin pellets 3 - 4 mm in length and dried in a dryer oven at 100 °C for 8 hours. The melt flow rate of the polymer was measured to be 1.4 g / 10 min at 3.8 kg at 230 °C. The refractive index of the resulting polymer was measured to be 1.492 at 589 nm.

[0091] was used 1 H NMR confirmed that the resulting polymer had a composition of pMMA / tert-butylcyclohexyl methacrylate / methacrylic acid (95.8 / 1.2 / 3.0 w / w). was used 13 C NMR determined the syndiotacticity of the copolymer to be 50% from the chemical shift at 44.5 ppm, while the isotacticity and atacticity were measured to be 8% and 42% from 45.5 ppm and 45.0 ppm. Using DSC in N 2 The glass transition temperature of the resin was measured to be 123 °C at a heating rate of 10 °C / min, while the Vicat temperature was detected to be 123 °C under 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 plaque was measured to be 91.9% at 560 nm using a Lambda 950 with a 150 mm integrating sphere, while the haze was measured to be 1.0% using a haze meter (Haze Gard Plus from BYK). The tensile modulus of the test sample was 3.3 GPa, while the tensile strength was 75 MPa, and the tensile elongation was 9.6%.

[0092] Comparative 1 (pMMA copolymer containing 4.8% MAA, with Tg = 124 °C) This example shows the preparation of a high-molecular-weight copolymer with 4.8% methacrylic acid. 9480 parts of methyl methacrylate and 480 parts of tert-butylcyclohexyl methacrylate were charged into a reaction vessel at a temperature close to 0 °C under N 2 and with a mechanical stirring speed of 100 rpm. Additionally, 1.6 parts of 531 (from Arkema) was used as the initiator, while 38 parts of n-dodecyl mercaptan (n-DDM from Aldrich) together with 1.0 part of ditert-dodecyl disulfide (DtDDS from Arkema) were used as the chain transfer agents. The polymerization reaction was carried out at 160 °C for 7 hours. When the conversion reached about 50%, the residual monomers were removed through the exhaust system. The resulting polymer was passed through a single-screw extruder at a die temperature of 240 °C while the barrel temperature was 230 - 250 °C. The melt flow passed through a water bath before pelletization. Then the polymer was pelletized into resin pellets 3 - 4 mm in length and dried in a dryer oven at 100 °C for 8 hours. The melt flow rate of the polymer was measured to be 2.2 g / 10 min at 3.8 kg at 230 °C. The refractive index of the resulting polymer was measured to be 1.494 at 589 nm.

[0093] was used 1 1H NMR confirmed that the resulting polymer had a composition of pMMA / methacrylic acid (96.3 / 3.7 w / w). Using 13 13C NMR determined the syndiotacticity of the copolymer to be 50% from the chemical shift at 44.5 ppm, while the isotacticity and atacticity were measured to be 8% and 42% from 45.5 ppm and 45.0 ppm. Using DSC in N 2 2, the glass transition temperature of the resin was measured to be 124 °C at a heating rate of 10 °C / min, while the Vicat temperature was detected to be 121 °C under 10 N. Using GPC, the weight-average molecular weight Mw of the resin was measured to be 82,000 g / mol, and the Mw / Mn (polydispersity) value was 2.0. Using a Lambda950 with a 150 mm integrating sphere, the light transmittance from a 3.2 mm plaque was measured to be 92.0% at 560 nm, while the haze was measured to be 1.0% using a haze meter (Haze Gard Plus from BYK). The tensile modulus of the test sample was 3.5 GPa, while the tensile strength was 73 MPa, and the tensile elongation was 6.9%.

[0094] Table 1. Summary of data on the solubility of pMMA copolymers in (hydrophobic) toluene and the water absorption of plaque samples.

[0095]

[0096]

Claims

1. A high-Tg, optically transparent, hydrophobic acrylic copolymer composition comprising a high-Tg copolymer, said high-Tg copolymer comprising: a) 0.1 wt% to 10.0 wt% of monomer units selected from tert-butylcyclohexyl methacrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, and mixtures thereof, wherein the tert-butylcyclohexyl methacrylate and / or 3,3,5-trimethylcyclohexyl (meth)acrylate monomer units have a trans / cis ratio of 50 / 50 to 85 / 15; b) at least 80 wt% of methyl methacrylate monomer units; c) 0 wt% to 10 wt% of other monomer units copolymerizable with methyl methacrylate; wherein the high-Tg copolymer has a Tg of 116 °C to 140 °C, and wherein the other monomers comprise 0.01 wt% to 10 wt% of methacrylic acid.

2. The high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the high-Tg copolymer has a Tg of 120 °C to 130 °C.

3. The high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the tert-butylcyclohexyl methacrylate and / or 3,3,5-trimethylcyclohexyl (meth)acrylate monomer units have a trans / cis ratio of 50 / 50 to 80 / 20.

4. The high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the tert-butylcyclohexyl methacrylate and / or 3,3,5-trimethylcyclohexyl (meth)acrylate monomer units have a trans / cis ratio of 50 / 50 to 75 / 25.

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

6. The high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the high-Tg copolymer has a weight-average molecular weight of 55,000 g / mol to 200,000 g / mol.

7. The high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the high-Tg copolymer has a weight-average molecular weight of 75,000 g / mol to 200,000 g / mol.

8. The high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the high-Tg copolymer has a weight-average molecular weight greater than 90,000 g / mol and not greater than 200,000 g / mol.

9. The high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the composition has a TWLT of at least 89%; and an optical haze of less than 5% measured on a 3.2 mm thick plaque using ASTM method D1003.

10. The high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the composition has a TWLT of at least 91%; and an optical haze of less than 3% measured using ASTM method D1003 on a 3.2 mm thick plaque.

11. The high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the composition has a TWLT of at least 92%; and an optical haze of less than 2% measured using ASTM method D1003 on a 3.2 mm thick plaque.

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

13. The high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the composition comprises a blend of the high-Tg copolymer and one or more compatible polymers, wherein the high-Tg copolymer is present in the blend in an amount of 5 wt% to 95 wt% of the total polymer solids.

14. The high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the composition comprises a blend of the high-Tg copolymer and one or more compatible polymers, wherein the high-Tg copolymer is present in the blend in an amount of 5 wt% to 75 wt% of the total polymer solids.

15. The high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the composition comprises a blend of the high-Tg copolymer and one or more compatible polymers, wherein the high-Tg copolymer is present in the blend in an amount of 10 wt% to 60 wt% of the total polymer solids.

16. An article comprising the high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the article is a lighting tube, a thin-walled part, an optical lens, an extruded film, an extruded profile, a cast sheet, a composite material, or an LED / OLED optical component.

17. An article comprising the high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the article is a thermoformable sheet.

18. An article comprising the high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the article is an extruded sheet.

19. An article comprising the high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the article is a co-extruded profile.

20. An article comprising the high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the article is a co-extruded sheet.

21. An article comprising the high-Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the article is a co-extruded profile for use in construction.

22. An article comprising the high Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the article is a co-extruded profile for use in a structure.

23. An article comprising the high Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the article is a co-extruded profile for use in a reflective sign.

24. The high Tg, optically transparent, hydrophobic acrylic copolymer composition according to claim 1, wherein the a) monomer units include tert-butylcyclohexyl methacrylate and 3,3,5-trimethylcyclohexyl (meth)acrylate, and the tert-butylcyclohexyl methacrylate and 3,3,5-trimethylcyclohexyl (meth)acrylate monomer units have a trans / cis ratio of 50 / 50 to 85 / 15.

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