High-transparency and high-hardness PC-PMMA alloy and preparation method thereof

Abstract

The invention discloses a preparation method of a high-transparency and high-hardness PC-PMMA alloy, and relates to the field of high polymer materials. Comprising the following steps: S1, blending, extruding and granulating PC, PBAT, PETS and a chain extender to obtain PC master batches with the refractive index of less than or equal to 1.58; s2, PMMA, SAN and the St-MMA-GMA terpolymer are blended, extruded and granulated, and PMMA master batches with the refractive index larger than or equal to 1.56 are obtained; s3, the PC master batch, the PMMA master batch, the compatilizer, the antioxidant and the lubricant are blended, extruded and granulated, and the high-transparency and high-hardness PC-PMMA alloy is obtained; according to the method disclosed by the invention, the refractive index difference between the PC master batch and the PMM master batch is reduced, the flowability is closer, the compatibility is higher, and the PC / PMMA alloy with high transparency, high hardness and good mechanical properties is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a PC-PMMA alloy with high transparency and high hardness and a preparation method thereof. Background Art

[0002] Polycarbonate (PC) has high impact strength and excellent comprehensive mechanical, thermal and electrical properties, and is widely used in other fields such as automobiles, aerospace, medical devices, electronic appliances, household appliances, display housings, communication equipment housing components, etc. However, it also has some obvious disadvantages: poor fluidity, insufficient surface hardness, poor chemical resistance, etc.

[0003] Polymethyl methacrylate (PMMA) is a thermoplastic plastic with a density of 1.19-1.20, extremely high transparency, a transmittance as high as 91%-93%, light weight, an anti-fragmentation performance 12-18 times that of ordinary silica glass, mechanical strength and toughness more than 10 times that of ordinary glass, a hardness of more than 2H before treatment, and a surface hardness of up to 5H or more after surface strengthening, scratch-resistant, with outstanding weather resistance and aging resistance, unchanged impact strength at low temperatures (-50 to -60 °C) and relatively high temperatures (below 100 °C), good electrical insulation performance, resistant to electric arc, stable chemical properties, and resistant to general chemical corrosion.

[0004] In the prior art, by blending PC and PMMA, the high toughness of PC and the surface hardness of PMMA can be combined to achieve complementary advantages and improve the comprehensive performance of the material, but there are the following technical bottlenecks:

[0005] 1. Poor compatibility: PC and PMMA are a partially compatible system, and direct blending easily leads to serious phase separation and reduced transparency;

[0006] 2. Refractive index difference: The refractive index of PC is about 1.58, and that of PMMA is about 1.49. After traditional blending, the interfacial scattering is serious and the haze of the material is high;

[0007] 3. Mismatched fluidity: The melt flow rate of PC and PMMA varies greatly (the melt index of PC is about 15 g / 10 min, and the melt index of PMMA is about 5 g / 10 min), and layering or defects are likely to occur during coextrusion;

[0008] 4. The addition of traditional compatibilizers affects the surface hardness (for example, silicone additives reduce the hardness by 10-20%). Summary of the Invention

[0009] The present invention aims to solve the technical problems existing in the blending of PC and PMMA, and provides a PC-PMMA alloy with high transparency and high hardness and a preparation method thereof. By the method of the present invention, the refractive index difference between the PC masterbatch and the PMM masterbatch is reduced, the fluidity is closer, and the compatibility is higher, so as to obtain a PC / PMMA alloy with both high transparency, high hardness and good mechanical properties.

[0010] The present invention is realized by the following technical solutions:

[0011] The first object of the present invention is to provide a preparation method of a PC-PMMA alloy with high transparency and high hardness, comprising the following steps:

[0012] S1. Blending and extruding PC, PBAT, PETS, and a chain extender to granulate, obtaining a PC masterbatch with a refractive index ≤ 1.58;

[0013] S2. Blending and extruding PMMA, SAN, and a St-MMA-GMA terpolymer to granulate, obtaining a PMMA masterbatch with a refractive index ≥ 1.56;

[0014] S3. Blending and extruding the PC masterbatch, the PMMA masterbatch, a compatibilizer, an antioxidant, and a lubricant to granulate, obtaining a PC-PMMA alloy with high transparency and high hardness.

[0015] Further, in the blending system of step S1, by mass percentage, the content of PBAT is 10-20%, the content of PETS is 1-3%, the content of the chain extender is 0.5-1%, and the balance is PC.

[0016] Further, the weight-average molecular weight of PC is 20,000-30,000, the weight-average molecular weight of PBAT is 50,000-80,000, and the weight-average molecular weight of the epoxy chain extender is 5,000-45,000.

[0017] Further, the chain extender adopts an epoxy chain extender.

[0018] Further, in the blending system of step S2, by mass percentage, the content of SAN is 20-30%, the content of the St-MMA-GMA terpolymer is 10-20%, and the balance is PMMA.

[0019] Further, the weight-average molecular weight of PMMA is 5,000-100,000, the weight-average molecular weight of SAN is 10,000-30,000, and the weight-average molecular weight of the St-MMA-GMA terpolymer is 5,500-6,000.

[0020] Further, in step S3, by mass percentage, the content of the PC masterbatch is 70-82%, the content of the PMMA masterbatch is 15-25%, the content of the compatibilizer is 2-5%, the content of the antioxidant is 0.1-0.3%, and the content of the lubricant is 0.2-0.5%.

[0021] Further, step S3 specifically includes the following steps:

[0022] S31. Mix the PC masterbatch, PMMA masterbatch, compatibilizer, antioxidant and lubricant in proportion;

[0023] S32. Use a twin-screw extruder to melt, extrude and pelletize;

[0024] S33. Cut the pellets and dry them in vacuum at 80-90°C for 2-3 hours to obtain a high-transparency and high-hardness PC-PMMA alloy.

[0025] Further, the temperature settings of the twin-screw extruder are as follows: zone 1: 200-220°C, zone 2: 220-240°C, zone 3: 240-260°C, zone 4: 260-280°C, head: 280-300°C, screw speed: 300-400 rpm / min.

[0026] The second object of the present invention is to provide a high-transparency and high-hardness PC-PMMA alloy prepared by the aforementioned method.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0028] 1. By introducing PBAT and PETS into the PC phase, the present invention can reduce the refractive index of PC while maintaining its transparency and improve the surface hardness of PC; by introducing SAN and St-MMA-GMA into the PMMA phase, PMMA can maintain transparency and increase the refractive index, and at the same time improve the compatibility with PC; since the refractive index difference between the two masterbatches is less than 0.02, the fluidity is closer and the compatibility is higher, and the transparency of the alloy material can be improved after blending, and a PC / PMMA alloy with both high transparency, high hardness and good mechanical properties can be prepared.

[0029] 2. The present invention adopts a step-by-step pelletizing method. By co-blending and extruding PC, PBAT, PETS and chain extender to pelletize, a PC masterbatch with a refractive index ≤ 1.58 is obtained, and by co-blending and extruding PMMA, SAN and St-MMA-GMA terpolymer to pelletize, a PMMA masterbatch with a refractive index ≥ 1.56 is obtained; since the components of PC and PMMA are kept independent respectively, each component is fully dissolved in PC during PC pelletizing and each component is fully dissolved in PMMA during PMMA pelletizing, achieving molecular-level mutual solubility respectively. After step-by-step regulating the compatibility and refractive index of the components and then blending, the formed alloy has better compatibility and smaller refractive index difference, which is more conducive to maintaining performance. Detailed implementation manners

[0030] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following combines embodiments to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the illustrative implementation manners and descriptions of the present invention are only used to explain the present invention and are not used to limit the present invention.

[0031] The following details the implementation manners of a PC-PMMA alloy with high transparency and high hardness and its preparation method according to the present invention. However, there will be cases where unnecessary details are omitted. For example, there are cases of omitting detailed descriptions of well-known matters and repeated descriptions. This is to avoid the following descriptions from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art.

[0032] The "range" disclosed in this application is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a specific range. The range defined in this way can include the end values or not include the end values, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range.

[0033] If there is no special description, all the implementation manners and optional implementation manners of this application can be combined with each other to form a new technical solution.

[0034] If there is no special description, all the technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0035] If there is no special description, the "including" and "comprising" mentioned in this application mean open-ended or can also be closed-ended. For example, the "including" and "comprising" can mean that other substances not listed can also be included or comprised, or can only include or comprise the substances listed.

[0036] If there is no special description, all the steps of this application can be carried out in sequence or randomly, and preferably in sequence. For example, the method includes steps (a) and (b), which means that the method can include steps (a) and (b) carried out in sequence, or can also include steps (b) and (a) carried out in sequence. For example, it is mentioned that the method may further include step (c), which means that step (c) can be added to the method in any order. For example, the method can include steps (a), (b) and (c), or can also include steps (a), (c) and (b), or can also include steps (c), (a) and (b), etc.

[0037] In a first aspect, the present invention provides a preparation method of a PC-PMMA alloy with high transparency and high hardness, including the following steps:

[0038] S1. Blend and extrude PC (polycarbonate), PBAT (polybutylene adipate terephthalate), PETS (pentaerythritol stearate), and chain extender to granulate, obtaining a PC masterbatch with a refractive index ≤ 1.58;

[0039] S2. Blend and extrude PMMA (polymethyl methacrylate), SAN (styrene-acrylonitrile copolymer), and St-MMA-GMA terpolymer to granulate, obtaining a PMMA masterbatch with a refractive index ≥ 1.56; wherein, St-MMA-GMA is copolymerized from styrene St, methyl methacrylate MMA, and glycidyl methacrylate GMA;

[0040] S3. Blend and extrude the PC masterbatch, PMMA masterbatch, compatibilizer, antioxidant, and lubricant to granulate, obtaining a PC-PMMA alloy with high transparency and high hardness.

[0041] By introducing PBAT and PETS into the PC phase in the present invention, while maintaining the transparency of PC, its refractive index can be reduced and the surface hardness of PC can be improved; by introducing SAN and St-MMA-GMA into the PMMA phase, PMMA can maintain transparency and increase the refractive index, and at the same time, the compatibility with PC is improved; due to the refractive index difference between the two masterbatches being less than 0.02, the fluidity is closer, and the compatibility is higher. After blending, the transparency of the alloy material can be improved, and a PC / PMMA alloy with both high transparency, high hardness, and good mechanical properties can be prepared.

[0042] Moreover, the present invention adopts a step-by-step granulation method. By blending and extruding PC, PBAT, PETS, and chain extender to granulate, a PC masterbatch with a refractive index ≤ 1.58 is obtained. By blending and extruding PMMA, SAN, and St-MMA-GMA terpolymer to granulate, a PMMA masterbatch with a refractive index ≥ 1.56 is obtained; since the components of PC and PMMA remain independent respectively, when PC is granulated, each component is fully dissolved in PC, and when PMMA is granulated, each component is fully dissolved in PMMA, achieving molecular-level mutual solubility respectively. After step-by-step regulating the compatibility and refractive index of the components, the alloy formed by blending has better compatibility, smaller refractive index difference, and is more conducive to maintaining performance.

[0043] Specifically, the preparation steps of the PC masterbatch with a refractive index ≤ 1.58 include:

[0044] S11. Premixing: Put PC particles, PBAT, PETS, and chain extender into a high-speed mixer according to a ratio, with a rotation speed of 800 - 1200 rpm / min, and mix for 10 - 15 minutes;

[0045] S12. Extrusion granulation: Use a twin-screw extruder. Temperature distribution: Zone 1: 180 - 200 °C, Zone 2: 200 - 220 °C, Zone 3: 220 - 240 °C, Zone 4: 240 - 260 °C, die head: 260 - 280 °C, screw speed: 200 - 300 rpm;

[0046] S13. Cooling, pelletizing and drying: Pelletize through water ring or air cooling, and obtain low refractive index PC masterbatch (refractive index ≤ 1.58) after drying.

[0047] Specifically, the preparation steps of PMMA masterbatch with refractive index ≥ 1.56 include:

[0048] S21. Premixing: Put PMMA, SAN, and St-MMA-GMA into a kneader in proportion. Temperature: 160 - 180 °C, rotor speed: 60 - 80 rpm / min, kneading for 15 - 20 minutes

[0049] S22. Extrusion granulation: Use a twin-screw extruder. Temperature setting: Zone 1: 180 - 200 °C, Zone 2: 200 - 220 °C, Zone 3: 220 - 240 °C, Zone 4: 240 - 260 °C, die head: 260 - 280 °C, screw speed: 150 - 250 rpm.

[0050] S23. Cooling, pelletizing and drying: Pelletize through water ring or air cooling, and dry in an oven at 80 - 100 °C for 4 - 6 hours to obtain high refractive index PMMA masterbatch (refractive index ≥ 1.56).

[0051] Through step-by-step granulation, low refractive index PC masterbatch and high refractive index PMMA masterbatch are obtained respectively. The regulation of their refractive indices and compatibility is closer, making the refractive index difference less than 0.02.

[0052] Further, in the blending system of step S1, by mass percentage, the content of PBAT is 10 - 20%, the content of PETS is 1 - 3%, the content of chain extender is 0.5 - 1%, and the balance is PC.

[0053] Further, the weight-average molecular weight of PC is 20000 - 30000, the weight-average molecular weight of PBAT is 50000 - 80000, and the weight-average molecular weight of epoxy chain extender is 5000 - 45000.

[0054] Further, the chain extender adopts an epoxy chain extender, such as ADR-4368, and this epoxy chain extender is used in the following examples.

[0055] Further, in the blending system of step S2, by mass percentage, the content of SAN is 20 - 30%, the content of St-MMA-GMA terpolymer is 10 - 20%, and the balance is PMMA.

[0056] Further, the weight-average molecular weight of PMMA is 5,000 to 100,000, the weight-average molecular weight of SAN is 10,000 to 30,000, and the weight-average molecular weight of the St-MMA-GMA terpolymer is 5,500 to 6,000.

[0057] Further, in step S3, by mass percentage, the PC masterbatch content is 70-82%, the PMMA masterbatch content is 15-25%, the compatibilizer content is 2-5%, the antioxidant content is 0.1-0.3%, and the lubricant content is 0.2-0.5%.

[0058] Further, step S3 specifically includes the following steps:

[0059] S31. Mix the PC masterbatch, PMMA masterbatch, compatibilizer, antioxidant, and lubricant in proportion;

[0060] S32. Use a twin-screw extruder for melt extrusion and pelletizing;

[0061] S33. Cut the pellets, vacuum dry at 80-90°C for 2-3 hours to obtain a high-transparency and high-hardness PC-PMMA alloy.

[0062] Further, the temperature settings of the twin-screw extruder are as follows: zone 1: 200-220°C, zone 2: 220-240°C, zone 3: 240-260°C, zone 4: 260-280°C, head: 280-300°C, and screw speed: 300-400 rpm / min.

[0063] In a second aspect, the present invention provides a high-transparency and high-hardness PC-PMMA alloy prepared by the aforementioned method.

[0064] The technical solution of the present invention will be further described in detail below in conjunction with embodiments.

[0065] It should be noted that the experimental methods used in the embodiments are all conventional methods unless otherwise specified. The materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and those skilled in the art can obtain them through commercial channels without special instructions.

[0066] Example 1

[0067] A preparation method of a high-transparency and high-hardness PC-PMMA alloy includes the following steps:

[0068] S1. Preparation of a low-refractive-index PC blend

[0069] Formulation design (by mass percentage):

[0070] PC (Mw = 20,000-30,000): 77%

[0071] PBAT (Mw = 50000 - 80000): 20%

[0072] PETS (stearate lubricant): 2%

[0073] Epoxy chain extender (ADR - 4368): 1%

[0074] Process steps:

[0075] S11. Premixing: Put PC particles, PBAT, PETS, and epoxy chain extender into a high - speed mixer in proportion, with a rotation speed of 800 - 1200 rpm / min and mix for 10 - 15 minutes;

[0076] S12. Extrusion granulation: Use a twin - screw extruder, with the temperature distribution: zone 1 180 - 200 °C, zone 2 200 - 220 °C, zone 3 220 - 240 °C, zone 4 240 - 260 °C, die head 260 - 280 °C, and screw rotation speed 200 - 300 rpm;

[0077] S13. Cooling, granulation, and drying: Granulate through water ring or air cooling, and obtain low - refractive - index PC masterbatch after drying.

[0078] The refractive index of the low - refractive - index PC masterbatch obtained in this step is detected to be 1.575.

[0079] S2. Preparation of high - refractive - index PMMA blend

[0080] Formulation design (mass percentage):

[0081] PMMA: 60%

[0082] SAN: 30%

[0083] St - MMA - GMA terpolymer (styrene / methyl methacrylate / glycidyl methacrylate): 10%

[0084] Process steps:

[0085] S21. Premixing: Put PMMA, SAN, and St - MMA - GMA into a kneader in proportion, with a temperature of 160 - 180 °C, rotor rotation speed of 60 - 80 rpm / min, and knead for 15 - 20 minutes;

[0086] S22. Extrusion granulation: Use a twin - screw extruder, with the temperature setting: zone 1 180 - 200 °C, zone 2 200 - 220 °C, zone 3 220 - 240 °C, zone 4 240 - 260 °C, die head 260 - 280 °C, and screw rotation speed 150 - 250 rpm;

[0087] S23. Cooling, pelletizing, and drying: Pelletize through a water ring or air cooling, and dry in an oven at 80 - 100°C for 4 - 6 hours to obtain high refractive index PMMA masterbatch.

[0088] Detect that the refractive index of the high refractive index PMMA masterbatch obtained in this step is 1.565.

[0089] S3. Preparation of PC - PMMA alloy material

[0090] Blending formula (mass percentage):

[0091] Low refractive index PC masterbatch: 79.5%

[0092] High refractive index PMMA masterbatch: 15%

[0093] Compatibilizer (SEBS - g - MAH): 5%

[0094] Antioxidant (1010): 0.2%

[0095] Lubricant (EBS): 0.3%

[0096] Blending process:

[0097] S31. Pre - drying: Dry the two masterbatches at 100°C for 4 hours respectively;

[0098] S32. Melting and blending: Set the temperature of the twin - screw extruder: zone 1 200 - 220°C, zone 2 220 - 240°C, zone 3 240 - 260°C, zone 4 260 - 280°C, die head 280 - 300°C, screw speed 300 - 400 rpm;

[0099] S33. Granulation and pelletizing: Use an underwater pelletizing system to cut into particles with a diameter of 1.5 - 2.0 mm;

[0100] S34. Post - treatment: Treat the granular product in a vacuum drying oven at 80°C for 2 hours.

[0101] Comparative Example 1

[0102] The difference between this comparative example and Example 1 is that: Step S1 is not included, that is, PBAT, PETS, and chain extender are not introduced into the PC phase.

[0103] A preparation method of a PC - PMMA alloy, comprising the following steps:

[0104] S1. Preparation of high refractive index PMMA blend (the formula is the same as the high refractive index PMMA formula in Example 1)

[0105] Put PMMA, SAN, and St-MMA-GMA into a kneader in proportion, with the temperature at 160 - 180 °C, the rotor speed at 60 - 80 rpm / min, and knead for 15 - 20 minutes;

[0106] Use a twin-screw extruder to extrude and pelletize, with the temperature settings: zone 1 at 180 - 200 °C, zone 2 at 200 - 220 °C, zone 3 at 220 - 240 °C, zone 4 at 240 - 260 °C, the die head at 260 - 280 °C, and the screw speed at 150 - 250 rpm;

[0107] Pelletize through a water ring or air cooling, and dry in an oven at 80 - 100 °C for 4 - 6 hours to obtain high refractive index PMMA masterbatch.

[0108] S2. Preparation of PC-PMMA alloy material (the formula is the same as that of the PC-PMMA alloy material in Example 1, except that the low refractive index PC masterbatch is replaced with untreated PC particles)

[0109] Dry the PC particles and the high refractive index PMMA masterbatch at 100 °C for 4 hours respectively;

[0110] Melt and co-extrude in a twin-screw extruder, with the temperature settings: zone 1 at 200 - 220 °C, zone 2 at 220 - 240 °C, zone 3 at 240 - 260 °C, zone 4 at 260 - 280 °C, the die head at 280 - 300 °C, and the screw speed at 300 - 400 rpm;

[0111] Use an underwater pelletizing system to cut into particles with a diameter of 1.5 - 2.0 mm;

[0112] Treat the particle product in a vacuum drying oven at 80 °C for 2 hours.

[0113] Comparative Example 2

[0114] The difference between this comparative example and Example 1 is that it does not include step S2, that is, the SAN, St-MMA-GMA terpolymer is not introduced into the PMMA phase.

[0115] A preparation method of a PC-PMMA alloy, comprising the following steps:

[0116] S1. Preparation of low refractive index PC blend (the formula is the same as that of the low refractive index PC in Example 1)

[0117] Put PC, PBAT, PETS, and an epoxy chain extender into a high-speed mixer in proportion, with the speed at 800 - 1200 rpm / min, and mix for 10 - 15 minutes;

[0118] Pelletizing is carried out by using a twin-screw extruder. The temperature distribution is as follows: zone 1: 180 - 200 °C, zone 2: 200 - 220 °C, zone 3: 220 - 240 °C, zone 4: 240 - 260 °C, die head: 260 - 280 °C, and the screw speed is 200 - 300 rpm;

[0119] After pelletizing by water ring or air cooling and drying, a low refractive index PC masterbatch is obtained.

[0120] S2. Preparation of PC-PMMA alloy material (the formula is the same as that of the PC-PMMA alloy material in Example 1, except that the high refractive index PMMA masterbatch is replaced with untreated PMMA)

[0121] The low refractive index PC masterbatch and PMMA are dried at 100 °C for 4 hours respectively;

[0122] The twin-screw extruder is used for melt blending and extrusion. The temperature settings are as follows: zone 1: 200 - 220 °C, zone 2: 220 - 240 °C, zone 3: 240 - 260 °C, zone 4: 260 - 280 °C, die head: 280 - 300 °C, and the screw speed is 300 - 400 rpm;

[0123] An underwater pelletizing system is adopted to cut into particles with a diameter of 1.5 - 2.0 mm;

[0124] The granular product is processed in a vacuum drying oven at 80 °C for 2 hours.

[0125] Comparative Example 3

[0126] The difference between this comparative example and Example 1 is that instead of stepwise pelletizing, all materials are directly blended.

[0127] A preparation method of a PC-PMMA alloy includes the following steps:

[0128] Weigh the components according to the content of each component in the formula of Example 1. After mixing all the raw materials evenly, use a twin-screw extruder for melt blending and extrusion. The temperature settings are as follows: zone 1: 200 - 220 °C, zone 2: 220 - 240 °C, zone 3: 240 - 260 °C, zone 4: 260 - 280 °C, die head: 280 - 300 °C, and the screw speed is 300 - 400 rpm;

[0129] An underwater pelletizing system is adopted to cut into particles with a diameter of 1.5 - 2.0 mm;

[0130] The granular product is processed in a vacuum drying oven at 80 °C for 2 hours.

[0131] The products obtained from the above Example 1 and Comparative Examples 1 - 3 are tested, and the results are shown in Table 1.

[0132] Table 1. Test results

[0133]

[0134] It can be seen from the test data of the masterbatch obtained by stepwise granulation in Example 1 that the refractive index of the low refractive index PC masterbatch is 1.575, and the refractive index of the high refractive index PMMA masterbatch is 1.565. The difference value between the two is 0.01. While the refractive index of untreated PC is about 1.58 and that of PMMA is about 1.49, and the refractive index difference value is 0.09. After blending, the interface scattering is serious, the haze is high, and the transparency is reduced. After being modified by the method of the present invention, the refractive indices of the two are adjusted to have a very small difference, effectively enhancing the transparency and compatibility of the composite material.

[0135] It can be seen from the data in Table 1 that compared with the PC / PMMA alloy without stepwise granulation in Comparative Example 3, the PC / PMMA alloy after stepwise granulation not only has higher fluidity and enhanced hardness, but also has a certain improvement in transmittance and mechanical properties. By stepwise regulating the component compatibility and refractive index matching, while maintaining the toughness of PC, the hardness and mechanical properties of the composite material are significantly improved. At the same time, only one masterbatch was modified in Comparative Example 2 and Comparative Example 3, and the performance in all aspects is inferior to that of Example 1, which also proves that only the alloy material prepared by the method of simultaneously modifying PC and PMMA and performing stepwise granulation can achieve the expected technical effect.

[0136] Finally, it should be noted that: the above specific embodiments are only used to illustrate the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the protection scope of the present invention; although the present invention has been described in detail with reference to the above specific embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the above embodiments, or perform equivalent substitution or improvement on some or all of the technical features; and these modifications, equivalent substitutions and improvements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A method for preparing a highly transparent and high hardness PC-PMMA alloy, characterized in that: The following steps are involved: S1, PC, PBAT, PETS and chain extender are blended and extruded to form granules to obtain PC masterbatch with a refractive index of ≤1.58; S2, blending PMMA, SAN, and St-MMA-GMA ternary copolymer and extruding and granulating to obtain PMMA masterbatch with a refractive index of ≥1.56; S3, PC masterbatch, PMMA masterbatch, compatibilizer, antioxidant and lubricant are mixed and extruded to form granules to obtain a PC-PMMA alloy with high transparency and high hardness.

2. The method for preparing a highly transparent and high hardness PC-PMMA alloy according to claim 1, characterized in that: In the blending system of step S1, by mass percentage, the PBAT content is 10-20%, the PETS content is 1-3%, the chain extender content is 0.5-1%, and the balance is PC.

3. The method for preparing a highly transparent and high hardness PC-PMMA alloy according to claim 1, characterized in that: The weight average molecular weight of PC is 20,000 to 30,000, the weight average molecular weight of PBAT is 50,000 to 80,000, and the weight average molecular weight of the epoxy chain extender is 5,000 to 45,000.

4. The method for preparing a highly transparent and high hardness PC-PMMA alloy according to claim 1, characterized in that: The chain extender is an epoxy chain extender.

5. The method for preparing a highly transparent and high hardness PC-PMMA alloy according to claim 1, characterized in that: In the blending system of step S2, by mass percentage, the content of SAN is 20-30%, the content of St-MMA-GMA terpolymer is 10-20%, and the balance is PMMA.

6. The method for preparing a highly transparent and high hardness PC-PMMA alloy according to claim 1, characterized in that: The weight average molecular weight of PMMA is 30,000-50,000, the weight average molecular weight of SAN is 40,000-60,000, and the weight average molecular weight of St-MMA-GMA terpolymer is 5,500-6,000.

7. The method for preparing a highly transparent and high hardness PC-PMMA alloy according to claim 1, characterized in that: In step S3, by mass percentage, the PC masterbatch content is 70-82%, the PMMA masterbatch content is 15-25%, the compatibilizer content is 2-5%, the antioxidant content is 0.1-0.3%, and the lubricant content is 0.2-0.5%.

8. The method for preparing a highly transparent and high hardness PC-PMMA alloy according to claim 1, characterized in that: Step S3 specifically includes the following steps: S31, mixing PC masterbatch, PMMA masterbatch, compatibilizer, antioxidant and lubricant according to proportion; S32, using a twin-screw extruder to melt extrude and granulate; S33, pelletizing, vacuum drying at 80-90°C for 2-3 hours to obtain a highly transparent and high hardness PC-PMMA alloy.

9. The method for preparing a highly transparent and high hardness PC-PMMA alloy according to claim 8, characterized in that: The temperature settings of the twin-screw extruder are: zone 1 200-220°C, zone 2 220-240°C, zone 3 240-260°C, zone 4 260-280°C, die head 280-300°C, screw speed 300-400rpm / min.

10. A highly transparent and high hardness PC-PMMA alloy prepared by the method according to any one of claims 1 to 9.

Images