Optical resin composition as well as preparation method and application thereof

Abstract

The invention discloses an optical resin composition as well as a preparation method and application thereof, and the resin composition is obtained by blending acrylic resin (A) with the glass transition temperature of 120 DEG C or above and inorganic silicate filler and / or nano silicon dioxide filler (B), wherein the acrylic resin (A) is prepared from methyl methacrylate, vinyl silicon dioxide and a third comonomer through prepolymerization, polymerization and devolatilization. The vinyl silicon dioxide exists on a polymer molecular chain in a chemical bonding form, so that the compatibilization effect between an organic phase and an inorganic phase is realized, the optical performance of the resin composition is improved, and meanwhile, the percolation effect of the inorganic filler is promoted, so that the resin composition has excellent high temperature resistance and water absorption resistance.

Description

Technical Field:

[0001] The present invention relates to an optical resin composition, a preparation method thereof and an application, and more specifically, to an optical resin composition with high temperature resistance, ultraviolet aging resistance and moisture absorption resistance. Background Art:

[0002] Polymethyl methacrylate (PMMA) is an acrylic resin mainly polymerized from methyl methacrylate. It has excellent optical properties, good chemical stability and dimensional stability, and has strong anti-fragmentation performance after orientation treatment. However, there is still much room for improvement in the impact resistance and ultraviolet aging resistance of ordinary PMMA. Usually, inorganic fillers such as silica are added to the PMMA resin matrix by mechanical blending to improve the impact resistance and ultraviolet aging resistance of the PMMA material.

[0003] Inorganic fillers such as silica, montmorillonite, wollastonite, vermiculite, etc. have their unique nano-scale particle, sheet and pore structures, and all have excellent properties such as rich pores, uniform particle size distribution, low density, good chemical stability, high temperature resistance and good electrical insulation. However, nano-scale fillers have a very high surface energy, and it is extremely easy for nano-particles or sheets to aggregate to form agglomerates at the micron scale or even higher scale, resulting in poor dispersibility of the filler, and some characteristics possessed by the original nano-particles such as surface effect, size effect, etc. will be difficult to manifest.

[0004] Since the process of introducing inorganic fillers into the PMMA system involves the mixing of organic-inorganic composites, the compatibility between the two greatly affects the final performance of the composite material. Mixing by mechanical blending easily leads to agglomeration of the filler in the PMMA matrix, resulting in crystal points and foreign matter points in the macroscopic material, which is instead not conducive to the mechanical properties and optical properties of PMMA.

[0005] In addition to simple blending, mixing can also be carried out by in-situ polymerization or sol-gel method. For example, the mixing methods disclosed in Patent CN1237113C and Patent CN100400558C improve the hardness of the PMMA resin, however, the problems of poor light transmittance and low mechanical strength still exist, and the material is opaque, which means that the mixing effect is not ideal.

[0006] Generally speaking, ordinary composite materials are only mixed at relatively macroscopic scales such as micrometers or even millimeters; while in hybrid materials, two or more materials are mixed at the microscopic scale and can exhibit new properties different from those of the original materials. If the microscale mixing between the organic PMMA matrix and the inorganic filler can be achieved, or the inorganic filler is bonded to the polymer in the form of a molecular bond, the reinforcing effect of the filler will be greatly improved. At the same time, this organic-inorganic bonding molecule will act as an interfacial compatibilizer between the organic / inorganic phases macroscopically, and also significantly improve the mixing effect of the unbonded inorganic filler in the organic matrix. Summary of the Invention:

[0007] The inventor of the present invention has conducted in-depth research to improve the impact resistance and ultraviolet aging resistance of PMMA resin, and the results show that: by copolymerizing nano-silica with vinyl groups on the surface and methacrylate, chemical bonding between the inorganic filler and the organic polymer matrix can be achieved, greatly enhancing the compatibility between the two and realizing molecular-level blending; using this resin material as the matrix, blending it with inorganic fillers such as silica, montmorillonite, wollastonite, vermiculite, etc. to prepare a resin composition, due to the ultra-high surface energy between the nano-filler and the bonded silica, the bonded silica exerts the effect of compatibilizing between the organic phase and the inorganic phase, enhancing the mixing ability of the inorganic filler and increasing the upper limit of the mixing ratio. The optical properties and mixing effect of this composition are much better than those of ordinary PMMA blended with it. In addition, the inventor also found that, thanks to the enhanced mixing effect, when the inorganic filler has a nano-sheet structure, the aggregated nano-sheet structure is opened and uniformly mixed into the matrix interior, promoting the formation and functioning of the percolation effect of the nano-filler, and a nano-scale dense and nearly continuous physical barrier appears inside the composition, unexpectedly enabling this resin composition to have excellent high-temperature and water absorption resistance and can be applied to display light guide plate materials in high humidity and high temperature environments.

[0008] The technical object of the present invention is achieved through the following technical solutions:

[0009] The present invention provides an optical resin composition, which comprises the following components (A) and (B):

[0010] 80 - 99 wt% of an acrylic resin (A) with a glass transition temperature of 120 °C or higher,

[0011] 1 - 20 wt% of an inorganic silicate filler and / or nano-silica filler (B).

[0012] Preferably:

[0013] 90 - 95 wt% of an acrylic resin (A) with a glass transition temperature of 120 °C or higher,

[0014] 5-10 wt% of inorganic silicate filler and / or nano-silica filler (B).

[0015] Among them, the acrylic resin (A) is obtained by polymerization of the following raw materials:

[0016] (1) 70-98.9 parts by mass of methyl methacrylate;

[0017] (2) 1-10 parts by mass of vinyl silica;

[0018] (3) 0.1-20 parts by mass of a third comonomer;

[0019] Preferably:

[0020] (1): 80-97 parts by mass of methyl methacrylate

[0021] (2): 3-8 parts by mass of vinyl silica;

[0022] (3): 2.5-15 parts by mass of a third comonomer.

[0023] The vinyl silica is selected from precipitated silica or fumed silica, with a surface double bond content of 25-250 mmol / kg, more preferably 25-50 mmol / kg; specific surface area of 150-250 m 2 / g, more preferably 175-225 m 2 / g; water content < 5%, more preferably water content < 1.5%; pH = 2.7-7.0, more preferably pH = 3.7-6.5.

[0024] The third comonomer is selected from monomers containing cycloolefin groups or phenyl groups, specifically selected from phenyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, (3,3,5-trimethylcyclohexyl) methacrylate, phenyl acrylate, cyclohexyl acrylate, vinyl cyclohexane, allyl cyclohexane, vinyl-4-methyl cyclohexane, 1,2-epoxy-4-vinyl cyclohexane, cyclohexyl vinyl ether, or one or more thereof.

[0025] In the present invention, the third monomer with a cyclic group in the side chain introduces a rigid group into the short side chain of the molecular chain, improving the high-temperature tolerance of the material while avoiding the problem of poor processing performance caused by the main chain containing a cyclic group. This increases the thermal decomposition temperature of the acrylic resin (A) and broadens the processing temperature range, reducing the thermal degradation of the resin caused by frictional heat generation during the blending process of the resin matrix and the inorganic filler, thereby achieving good heat resistance and physical and mechanical properties of the resin composition.

[0026] The component (B) is an inorganic filler, selected from one or more of fumed silica, montmorillonite, vermiculite, wollastonite.

[0027] For the acrylic resin (A) of the present invention, when the addition amount of vinyl silica is too low, the improvement effect of the present invention cannot be well demonstrated; when the addition amount is too high, the polymerization rate will decrease during the preparation process, and unnecessary cross-linking will occur between molecules.

[0028] The weight-average molecular weight of the acrylic resin (A) of the present invention is 80,000 - 180,000, preferably 85,000 - 120,000.

[0029] Another aspect of the present invention is to provide a method for preparing the above resin composition, which method comprises the following steps:

[0030] Step 1: Polymerization of acrylic resin (A):

[0031] (1-1) Prepolymerization batching: Add part of methyl methacrylate, all of the silica monomer, part of the third comonomer, and all of the reaction aids into the batching tank; fully stir to prepare the prepolymerization reaction solution.

[0032] (1-2) Prepolymerization: Add the above reaction solution into the reaction kettle, and carry out free radical or anionic prepolymerization reaction.

[0033] (1-3) Polymerization: Add the remaining methyl methacrylate and the remaining third comonomer into the reaction kettle, control the temperature in the reaction kettle to be the same as the reaction temperature in the (1-2) prepolymerization step, and carry out the polymerization reaction.

[0034] (1-4) Extrusion and devolatilization: Feed the material obtained in step (1-3) into a devolatilizing extruder to remove unreacted monomers and other volatile components and extrude and pelletize.

[0035] Step 2: Blending of acrylic resin (A) and inorganic filler (B), which process comprises the following two sub-steps:

[0036] (2-1) Weigh the acrylic resin (A) and inorganic filler (B) prepared in (1-4) in proportion and mix them evenly.

[0037] (2-2) Extrude and pelletize the evenly mixed material in (2-1) using a twin-screw extruder to obtain the acrylic resin / inorganic filler composition product.

[0038] In the method for preparing the composition provided by the present invention, the raw materials added in step (1-1) include: 2 to 10 parts by mass of methyl methacrylate and / or 0 to 10 parts by mass of a third comonomer, and 1 to 10 parts by mass of vinyl silica. The methyl methacrylate monomer and the third comonomer can be added simultaneously or separately to form a prepolymer monomer with the silica monomer. The addition amount of methyl methacrylate in step (1-1) accounts for 0.1% to 20% of the total amount of methyl methacrylate used.

[0039] In the method for preparing the composition provided by the present invention, the reaction assistant in step (1-1) is selected from the combination of a radical initiator and a chain transfer agent, or the combination of an anionic initiator and a co-initiator.

[0040] In the method for preparing the composition provided by the present invention, the prepolymerization temperature range in step (1-1) is 20-160°C, and the reaction time range is 0.5 to 10 min. This prepolymerization step will help the silica monomer react with the polymerization initiator to generate a silica-containing active center. The role of methyl methacrylate and / or the third monomer in this step is to stabilize the active center, appropriately initiate polymerization, and extend the molecular chain. For the polymer prepared by first performing prepolymerization and then polymerization, the silica is usually at the end of the molecular chain, which will help the silica-containing molecular chain improve the compatibility of the organic / inorganic interface, facilitate the insertion and mixing of the polymer in the lamellae of the inorganic filler (B), and establish a chemical basis for the formation of a percolation effect between the inorganic fillers.

[0041] In the present invention, the initiator is selected from radical initiators and chain transfer agents.

[0042] The optional radical initiators provided by the present invention include one or more of azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azobisisobutyrate, azodicarbonamide, benzoyl peroxide, dibenzoyl peroxide, tert-butyl benzoyl peroxide, tert-butyl peracetate, tert-butyl perisobutyrate, tert-butyl per-2-ethylhexanoate, tert-butyl per-3,5,5-trimethylhexanoate, 1,1-bis-(tert-butylperoxy)-3,3,5-trimethylcyclohexane; preferably azobisisobutyronitrile or tert-butyl per-3,5,5-trimethylhexanoate.

[0043] The addition amount of the initiator is 1×10 -3 ~5×10 -2 parts by mass based on 100 parts by mass of the monomer. When the addition amount of the initiator in the polymerization system is too low, the polymerization reaction rate is too slow and the conversion rate is low; when the addition amount of the initiator is too high, the heat release during the polymerization process is concentrated and the product is prone to gelation, which is not conducive to the application of the resin material.

[0044] PMMA resin requires an appropriate molecular weight during production, processing, and use. When the molecular weight is low, the resin has good fluidity, but its mechanical properties are difficult to meet the usage requirements. When the molecular weight is high, the resin has a low melt index, poor fluidity, difficult production and processing, and high energy consumption during the process. Therefore, it is necessary to adjust the PMMA molecular weight through a chain transfer agent.

[0045] The optional chain transfer agents provided by the present invention include one or more of 2-mercaptoethanol, n-butyl mercaptan, tert-butyl mercaptan, n-octyl mercaptan, isooctyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, mercaptoacetic acid, and isooctyl 3-mercaptopropionate. To adapt to different polymerization temperatures and initiator systems, it is preferably one or more of 2-mercaptoethanol, n-octyl mercaptan, and tert-dodecyl mercaptan.

[0046] The addition amount of the chain transfer agent is 0.05 - 0.5 parts by mass based on 100 parts by mass of the monomer, and preferably 0.10 - 0.30 parts by mass.

[0047] In the method for preparing acrylic resin (A) based on the anionic polymerization reaction mechanism provided by the present invention, the initiator system includes an anionic initiator and a co-initiator.

[0048] The optional anionic initiators provided by the present invention include one or more of n-butyl lithium, sec-butyl lithium, tert-butyl lithium, and isobutyl lithium, and preferably n-butyl lithium. The addition amount of the initiator is 5×10 -4 ~3×10 -2 parts by mass based on 100 parts by mass of the monomer, and preferably 1×10 -4 ~1×10 -2 parts by mass.

[0049] Usually, an alkyl aluminum is added as a co-initiator to the anionic polymerization system to coordinate with the anionic initiator to form an active center, react with trace impurities in the system, and protect the anionic initiator. In addition, the alkyl aluminum as a co-initiator can play a certain chain transfer role in the polymerization system to adjust the polymer molecular weight. The optional co-initiators provided by the present invention include one or more of triethyl aluminum, tripropyl aluminum, triisobutyl aluminum, trihexyl aluminum, and diisobutyl aluminum hydride, and preferably triethyl aluminum. The addition amount of the co-initiator is 0.01 - 0.50 parts by mass based on 100 parts by mass of the monomer, and preferably 0.05 - 0.20 parts by mass.

[0050] The polymerization implementation method of the present invention can be any one of bulk polymerization, solution polymerization, suspension polymerization, or emulsion polymerization. When choosing the free radical polymerization method, the bulk polymerization implementation method is preferred; when choosing the anionic polymerization method, the solution polymerization implementation method is preferred.

[0051] The solvent used in the solution polymerization method is not particularly limited as long as it can dissolve the monomers and the acrylate resin and does not deactivate free radicals or anions. One or more of aromatic hydrocarbons such as benzene, toluene, and ethylbenzene are preferred; the addition amount of the solvent is 35 to 100 parts by mass, preferably 45 to 65 parts by mass, based on 100 parts by mass of the monomers.

[0052] Regarding the temperature during the polymerization reaction, it can be appropriately set according to the polymerization implementation method or from viewpoints such as the polymerization reaction rate, the viscosity of the polymerization reaction solution, and the suppression of by-product formation. In free radical polymerization, when bulk polymerization is carried out, the temperature of the polymerization reaction is preferably 80 to 160 °C, more preferably 90 to 140 °C. In anionic polymerization, when solution polymerization is carried out, the temperature of the polymerization reaction is preferably 20 to 80 °C, more preferably 25 to 55 °C.

[0053] In the present invention, the outlet conversion rate of the reaction kettle is controlled to be 50% to 70%. When the outlet conversion rate is too low, production economy is not achieved. When the outlet conversion rate is too high, the viscosity of the materials in the kettle is too large, which is not conducive to mass transfer and heat transfer.

[0054] In the present invention, the devolatilization stage is used to remove unreacted monomers and / or solvents. When the devolatilization temperature is too low, the volatile components are not removed sufficiently; when the devolatilization temperature is too high, the polymer is prone to yellowing due to heat. In the devolatilization stage, the temperature of the devolatilization port is usually controlled at 230 - 300 °C, the vacuum degree is -0.095 MPa to -0.07 MPa, and the devolatilization time does not exceed 60 min.

[0055] In the preparation method provided by the present invention, the melting temperature of the extruder in the step (2 - 2) is 180 - 260 °C, and the screw speed is 100 - 800 rpm.

[0056] When preparing the acrylate resin composition by the above method, additives such as a release agent, an antioxidant, a colorant, and an antistatic agent can be added as needed, and the types and amounts of these additives are well known to those skilled in the art.

[0057] The present invention further provides a use of the optical resin composition for a display light guide plate for vehicles and ships.

[0058] The beneficial effects of the present invention are as follows:

[0059] The acrylic resin / inorganic filler composition provided by the present invention has excellent properties of high transparency, ultraviolet aging resistance, high temperature resistance, and low moisture absorption rate: methyl methacrylate and vinyl silica are copolymerized, and the silica is bonded to the polymer chain by a chemical bond, improving the compatibility of silica in the polymer; a third monomer with a large steric hindrance containing a naphthene group or a phenyl group is copolymerized with MMA and silica, increasing the thermal decomposition temperature and high temperature tolerance of the polymer, broadening the processing temperature of the resin, and at the same time the rigid ring of the non-main chain ensures good processing performance of the resin matrix; there is a good phase interface bonding ability between the silica groups in the polymer molecular chain and the inorganic filler added by blending, greatly improving the dispersibility of the inorganic filler in the organic polymer matrix, avoiding the agglomeration and precipitation of the inorganic filler, and making the light transmittance and haze of the composition basically the same as those of PMMA; the polymer chain end hybrid silica structure formed by the unique pre-polymerization reaction designed in the present invention improves the insertion effect of the polymer chain in the inorganic filler, especially in the nanosheet structure, promotes the percolation effect between the nanosheets, forms a dense and nearly continuous physical barrier layer in the composition, and endows the composition with excellent low moisture absorption performance and water barrier performance. Detailed implementation manners:

[0060] The implementation manners of the present invention will be further described below in conjunction with embodiments. However, the present invention is not limited to the listed embodiments, and should also include any other known changes within the scope of the rights required by the present invention.

[0061] The sources of the raw materials involved in the examples are shown in Table 1:

[0062] Table 1 Information of raw materials involved in the examples

[0063]

[0064]

[0065] The test methods for the relevant structures and properties of the polymer are as follows:

[0066] Conversion rate test

[0067] The conversion rate is calculated according to the ratio of the mass of the polymer dried after devolatilization to the feed amount of the reaction solution. In addition, a sampling tube is provided at the outlet of the reaction kettle, and the conversion rate can be calculated by measuring the specific gravity of the solid residue and the sample after devolatilization in a vacuum oven.

[0068] Molecular weight test

[0069] The molecular weight is tested by liquid phase gel chromatography (GPC). The instrument model is Water 996, the mobile phase is tetrahydrofuran (THF), and the detector uses a differential refractive index detector. Five chromatographic columns, all with a size of 7.8×300mm; monodisperse PMMA is used as the standard.

[0070] Testing of the content of copolymerized silica and the initial thermal decomposition temperature

[0071] Referring to the standard GB / T 27761-2011, using a thermogravimetric analyzer, heating at a rate of 10 °C / min in a nitrogen atmosphere, recording the temperature at which the weight loss ratio is 5% as the initial thermal decomposition temperature, and recording the residual weight ratio after the end of the heating process as the mass content of copolymerized silica.

[0072] Testing of the glass transition temperature

[0073] Referring to the standard GBT 19466.2-2004, using a differential scanning calorimeter, testing the glass transition temperature of the resin at a heating / cooling rate of 10 °C / min.

[0074] Testing of the light transmittance and yellowness value:

[0075] The optical properties can measure the total light transmittance, yellowness value YI, etc. through a color difference analyzer. Instrument model: Hunterlab VIS; Test standard: light transmittance ISO 13148, yellowness value: GB / T-38922.

[0076] Resistance to ultraviolet aging:

[0077] Referring to the standard GB / T-16422.3-2006, measuring the light transmittance and YI value of the resin composition after aging treatment in an ultraviolet aging chamber.

[0078] Testing of the water absorption rate:

[0079] Referring to the standard GB / T-1034-2008 Test method for water absorption of plastics, measuring the saturated water absorption rate of the resin composition.

[0080] Examples

[0081]

Manufacturing Example 1

[0082] Heat the ingredient tank and reaction kettle for polymerization to 120 °C, and at the same time perform operations of evacuating and introducing nitrogen to fully displace and remove impurities such as water and oxygen contained in the ingredient tank and reaction kettle.

[0083] Add 5 parts by mass of methyl methacrylate, 5 parts by mass of silica with a vinyl content of 25 mmol / kg, 2 parts by mass of phenyl methacrylate, 0.013 parts by mass of tert-butyl peroxy-3,5,5-trimethylhexanoate, and 0.2 parts by mass of n-octyl mercaptan into the ingredient tank, and mix well to prepare a prepolymerization reaction solution.

[0084] Add all the prepolymerization reaction solution into a continuous stirred-tank reactor (effective volume 10 L), control the temperature in the reactor at 135 °C, and the prepolymerization reaction time is 3 min.

[0085] The remaining 88 parts by mass of methyl methacrylate (the total amount of methyl methacrylate added is 93 parts by mass) was continuously added into a continuous stirred-tank reactor at a flow rate of 1.5 kg / h, and the temperature in the reactor was controlled at 135 °C with an average residence time of 2 h.

[0086] The slurry obtained from the above reaction was continuously fed into a devolatilizing twin-screw extruder, and unreacted monomers and other volatile components were removed under the conditions of a vacuum degree of -0.097 MPa, a temperature of 230 °C, and a residence time of 10 min. The devolatilized material was extruded and pelletized to obtain the product acrylic resin (A1).

[0087] The conversion rate at the outlet of the reactor was measured to be 65%, the weight-average molecular weight of the resin was 91,000, the mass content of copolymerized silica was 6%, the glass transition temperature was 121.5 °C, and the initial thermal decomposition temperature was 357.9 °C.

[0088]

Production Example 2

[0089] In the prepolymerization step, the amount of methyl methacrylate added was 5 parts by mass and the amount of silica added was 0 parts by mass. In the polymerization step, the amount of methyl methacrylate added was changed to 93 parts by mass, and other experimental conditions and operations were the same as in Production Example 1 to obtain the product acrylic resin (A2).

[0090] The conversion rate at the outlet of the reactor was measured to be 68%, the weight-average molecular weight of the resin was 88,000, the mass content of copolymerized silica was 0%, the glass transition temperature was 117.3 °C, and the initial thermal decomposition temperature was 343.6 °C.

[0091]

Production Example 3

[0092] The feeding tank and the reactor used for polymerization were heated to 120 °C, and at the same time, vacuum pumping and nitrogen purging operations were carried out to fully replace and remove impurities such as water and oxygen contained in the feeding tank and the reactor.

[0093] 4.5 parts by mass of silica with a vinyl content of 250 mmol / kg, 5 parts by mass of vinylcyclohexane, 0.015 parts by mass of tert-butyl peroxy-3,5,5-trimethylhexanoate, and 0.28 parts by mass of tert-dodecyl mercaptan were added into the feeding tank and thoroughly mixed to prepare a prepolymerization reaction solution.

[0094] All of the prepolymerization reaction solution was added into a continuous stirred-tank reactor (effective volume 10 L), and the temperature in the reactor was controlled at 140 °C with a prepolymerization reaction time of 3.5 min.

[0095] The remaining 90.5 parts by mass of methyl methacrylate (the total amount of methyl methacrylate added is 90.5 parts by mass) was continuously added into the continuous stirred-tank reactor at a flow rate of 1.5 kg / h, and the temperature in the reactor was controlled at 140 °C with an average residence time of 1.8 h.

[0096] The slurry obtained from the above reaction was continuously fed into a devolatilizing twin-screw extruder, and unreacted monomers and other volatile components were removed under the conditions of a vacuum degree of -0.097 MPa, a temperature of 230 °C, and a residence time of 20 min. The devolatilized material was extruded and pelletized to obtain the product acrylic resin (A3).

[0097] The conversion rate at the outlet of the reaction kettle was measured to be 67%, the weight-average molecular weight of the resin was 89,000, the mass content of copolymerized silica was 5.3%, the glass transition temperature was 123.2 °C, and the initial thermal decomposition temperature was 360.2 °C.

[0098]

Production Example 4

[0099] The amount of silica added in the prepolymerization step was 0 part by mass, and other experimental conditions and operations were the same as in Production Example 3 to obtain the product acrylic resin (A4).

[0100] The conversion rate at the outlet of the reaction kettle was measured to be 71%, the weight-average molecular weight of the resin was 90,000, the mass content of copolymerized silica was 0%, the glass transition temperature was 118.7 °C, and the initial thermal decomposition temperature was 332.3 °C.

[0101]

Production Example 5

[0102] The prepolymerization step was cancelled, the amount of methyl methacrylate added was changed to 100 parts by mass, the amount of silica added was 0 part by mass, and the amount of the third monomer added was 0 part by mass. After mixing methyl methacrylate with the initiator and chain transfer agent in the same ratio as in Production Example 3, it was directly added into the continuous stirred-tank reactor. Other experimental conditions and operations were the same as in Production Example 3 to obtain the product acrylic resin (A5).

[0103] The conversion rate at the outlet of the reaction kettle was measured to be 69%, the weight-average molecular weight of the resin was 94,000, the mass content of copolymerized silica was 0%, the glass transition temperature was 114 °C, and the initial thermal decomposition temperature was 303.4 °C.

[0104]

Production Example 6

[0105] The ingredient tank and reaction kettle used for polymerization were heated to 120 °C, and at the same time, vacuum pumping and nitrogen purging operations were carried out to fully displace and remove impurities such as water and oxygen contained in the ingredient tank and reaction kettle.

[0106] Add 2 parts by mass of methyl methacrylate, 10 parts by mass of styrene, 10 parts by mass of silica with a vinyl content of 50 mmol / kg, 0.010 part by mass of azobisisobutyronitrile, and 0.18 part by mass of n-octyl mercaptan into the batching tank, and mix well to prepare a prepolymerization reaction solution.

[0107] Add all the prepolymerization reaction solution into a continuous stirred-tank reactor (effective volume 10 L), control the temperature in the reactor at 85 °C, and the prepolymerization reaction time is 5 min.

[0108] Continuously add the remaining 78 parts by mass of methyl methacrylate (the total amount of methyl methacrylate added is 80 parts by mass) into the continuous stirred-tank reactor at a flow rate of 1.5 kg / h, control the temperature in the reactor at 80 °C, and the average residence time is 2 h.

[0109] Continuously feed the slurry obtained from the above reaction into a devolatilizing twin-screw extruder, and remove unreacted monomers and other volatile components under the conditions of a vacuum degree of -0.097 MPa, a temperature of 225 °C, and a residence time of 10 min. Granulate the devolatilized material by extrusion to obtain the product acrylic resin (A6).

[0110] The conversion rate at the outlet of the reactor is measured to be 67%, the weight-average molecular weight of the resin is 82,000, the mass content of copolymerized silica is 10%, the glass transition temperature is 119.4 °C, and the initial thermal decomposition temperature is 366.1 °C.

[0111]

Production Example 7

[0112] In the prepolymerization step, the amount of silica added is 0 part by mass, and in the polymerization step, the amount of styrene added is changed to 10 parts by mass (the total added amount is 20 parts by mass). Other experimental conditions and operations are the same as in Production Example 6 to obtain the product acrylic resin (A7).

[0113] The conversion rate at the outlet of the reactor is measured to be 60%, the weight-average molecular weight of the resin is 82,000, the content of copolymerized silica is 0%, the glass transition temperature is 115.0 °C, and the initial thermal decomposition temperature is 346.4 °C.

[0114]

Production Example 8

[0115] Heat the batching tank and the reactor used for polymerization to 120 °C, and at the same time perform operations of vacuum pumping and nitrogen purging to fully displace and remove impurities such as water and oxygen contained in the batching tank and the reactor.

[0116] Add 7 parts by mass of methyl methacrylate, 3 parts by mass of silica with a vinyl content of 75 mmol / kg, 0.005 part by mass of azobisisobutyronitrile, and 0.05 part by mass of mercaptoethanol into the batching tank, and mix well to prepare a prepolymerization reaction solution.

[0117] All of the prepolymerization reaction solution was added into a continuous stirred-tank reactor (effective volume: 10 L), the temperature in the reactor was controlled at 95 °C, and the prepolymerization reaction time was 2 min. The remaining 90 parts by mass of methyl methacrylate (the total amount of methyl methacrylate added was 97 parts by mass) was continuously added into the continuous stirred-tank reactor at a flow rate of 1.5 kg / h, the temperature in the reactor was controlled at 160 °C, and the average residence time was 1.5 h.

[0118] The slurry obtained from the above reaction was continuously fed into a devolatilizing twin-screw extruder, and unreacted monomers and other volatile components were removed under the conditions of a vacuum degree of -0.097 MPa, a temperature of 240 °C, and a residence time of 15 min. The devolatilized material was extruded and pelletized to obtain the acrylic resin product (A8).

[0119] The conversion rate at the outlet of the reactor was measured to be 75%, the weight-average molecular weight of the resin was 180,000, the mass content of copolymerized silica was 3.8%, the glass transition temperature was 121.5 °C, and the initial thermal decomposition temperature was 361.6 °C.

[0120]

Production Example 9

[0121] The batching tank and the reactor used for polymerization were heated to 140 °C, and at the same time, vacuum pumping and nitrogen purging operations were carried out to fully displace and remove impurities such as water and oxygen contained in the batching tank and the reactor.

[0122] 3 parts by mass of methyl methacrylate, 3 parts by mass of styrene, 3 parts by mass of silica with a vinyl content of 25 mmol / kg, 0.006 parts by mass of n-butyllithium, and 0.084 parts by mass of triethylaluminum were added into the batching tank and mixed thoroughly to prepare the prepolymerization reaction solution.

[0123] All of the prepolymerization reaction solution was added into a continuous stirred-tank reactor (effective volume: 10 L), the temperature in the reactor was controlled at 35 °C, and the prepolymerization reaction time was 8 min.

[0124] The remaining 82 parts by mass of methyl methacrylate (the total amount of methyl methacrylate added was 85 parts by mass) and the remaining 9 parts by mass of styrene (the total amount of styrene added was 12 parts) were continuously added into the continuous stirred-tank reactor (effective volume: 10 L) at a flow rate of 1.5 kg / h, the temperature in the reactor was controlled at 35 °C, and the average residence time was 3 h.

[0125] The slurry obtained from the above reaction was continuously fed into a devolatilizing twin-screw extruder, and unreacted monomers and other volatile components were removed under the conditions of a vacuum degree of -0.097 MPa, a temperature of 220 °C, and a residence time of 10 min. The devolatilized material was extruded and pelletized to obtain the acrylic resin product (A9).

[0126] The measured conversion rate at the reactor outlet was 88%, the weight-average molecular weight of the PMMA resin was 120,000, the mass content of copolymerized silica was 3.4%, the glass transition temperature was 125.7 °C, and the initial thermal decomposition temperature was 354.4 °C.

[0127] Table 2 Monomers and feeding ratios used in the production examples

[0128]

[0129]

Examples 1-5

[0130] According to the formulation in Table 3, first accurately weigh each raw material component, then mix the weighed components in a high-speed mixer at a rotation speed of 300 rpm for 8 minutes, and then use a twin-screw extruder (L / D = 64) to carry out granulation extrusion at a rotation speed of 400 rpm under the condition of a melt temperature of 220 °C.

[0131] Take the particles obtained after the above extrusion and dry them at 80 °C for 4 hours, process them into corresponding test bars, and test their relevant properties. The results are shown in Table 4.

[0132]

Comparative Examples 1-4

[0133] According to the formulation in Table 3, first accurately weigh each raw material component, then mix the weighed components in a high-speed mixer at a rotation speed of 300 rpm for 8 minutes, and then use a twin-screw extruder (L / D = 64) to carry out granulation extrusion at a rotation speed of 400 rpm under the condition of a melt temperature of 220 °C.

[0134] Take the particles obtained after the above extrusion and dry them at 80 °C for 4 hours, process them into corresponding test bars, and test their relevant properties. The results are shown in Table 4.

[0135] Table 3 Formulation for preparing the resin composition

[0136]

[0137] Table 4 Water absorption rate of the resin composition and optical properties before and after UV aging

[0138]

[0139]

Claims

1. An optical resin composition comprising the following components (A) and (B): 80 to 99 wt% of an acrylic resin (A) having a glass transition temperature of 120 °C or higher, 1 to 20 wt% of an inorganic silicate filler and / or nano-silica filler (B). Preferably: 90 - 95 wt% of an acrylic resin (A) having a glass transition temperature of 120 °C or higher, 5 - 10 wt% of an inorganic silicate filler and / or nano-silica filler (B).

2. The optical resin composition according to claim 1, wherein The acrylic resin (A) is obtained by a polymerization reaction of the following raw materials: (1) 70 to 98.9 parts by mass of methyl methacrylate; (2) 1 to 10 parts by mass of vinyl silica; (3) 0 to 20 parts by mass of a third comonomer; Preferably: (1) 80 to 97 parts by mass of methyl methacrylate (2) 3 to 8 parts by mass of vinyl silica; (3) 2.5 - 15 parts by mass of a third comonomer.

3. The optical resin composition according to claim 2, wherein The vinyl silica is selected from precipitated silica or fumed silica, the surface double bond content thereof is 25 to 250 mmol / kg, more preferably 25 to 50 mmol / kg; the specific surface area is 150 to 250 m 2 / g, more preferably 175 to 225 m 2 / g; the water content is <5%, more preferably the water content is <1.5%; pH = 2.7 to 7.0, more preferably pH = 3.7 to 6.

5.

4. The optical resin composition according to claim 2 or 3, wherein The third comonomer is selected from monomers containing a cycloolefin group or a phenyl group, specifically selected from one or more of phenyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, (3,3,5-trimethylcyclohexyl) methacrylate, phenyl acrylate, cyclohexyl acrylate, vinyl cyclohexane, propenyl cyclohexane, vinyl-4-methyl cyclohexane, 1,2-epoxy-4-vinyl cyclohexane, cyclohexyl vinyl ether.

5. The optical resin composition according to any one of claims 1 to 4, characterized in that, The component (B) is an inorganic filler, selected from one or more of fumed silica, montmorillonite, vermiculite, wollastonite.

6. The method for preparing the optical resin composition according to any one of claims 1-5, characterized in that, Comprising the following steps: Step 1: Polymerization of the acrylic resin (A): (1-1) Prepolymerization batching: Add part of the methyl methacrylate, all of the silica monomers, part of the third comonomer, and all of the reaction aids into the batching tank; stir well to prepare a prepolymerization reaction solution; (1-2) Prepolymerization: Add the above reaction solution into the reaction kettle, and carry out a free radical or anionic prepolymerization reaction; (1-3) Polymerization: Add the remaining methyl methacrylate and the remaining third comonomer into the reaction kettle, control the temperature in the reaction kettle to be the same as the reaction temperature in the (1-2) prepolymerization step, and carry out a polymerization reaction; (1-4) Extrusion and devolatilization: Feed the material obtained in step (1-3) into a devolatilizing extruder, remove unreacted monomers and other volatile components and extrude and pelletize; Step 2: Blending of the acrylic resin (A) and the inorganic filler (B), this process includes the following two sub-steps: (2-1) Weigh the acrylic resin (A) and the inorganic filler (B) prepared in (1-4) in proportion and mix them evenly; (2-2) Extrude and pelletize the evenly mixed material in (2-1) using a twin-screw extruder to obtain an acrylic resin / inorganic filler composition product.

7. The preparation method according to claim 6, characterized in that, In step (1-1), the reaction aids are selected from a combination of a free radical initiator and a chain transfer agent, or a combination of an anionic initiator and a co-initiator; and / or, the prepolymerization temperature range in step (1-1) is 20 - 160 °C, and the reaction time range is 0.5 - 10 min.

8. The preparation method according to claim 6 or 7, characterized in that, The raw materials added in step (1-1) include: 2 to 10 parts by mass of methyl methacrylate and / or 0 to 10 parts by mass of a third comonomer, and 1 to 10 parts by mass of vinyl silica.

9. The preparation method according to any one of claims 6-8, characterized in that, In step (2-2), the melting temperature of the extruder is 180 - 260 °C, and the screw speed is 100 - 800 rpm.

10. Use of the optical resin composition according to any one of claims 1-5 or the optical resin composition prepared by the preparation method according to any one of claims 6-9 in the light guide plates for vehicle and ship displays.

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