PC / PBT modified plastic and preparation method thereof

Abstract

The invention discloses a PC / PBT (polycarbonate / polybutylene terephthalate) modified plastic and a preparation method thereof in the technical field of modified plastics. The PC / PBT modified plastic comprises the following components in parts by weight: 70-80 parts of PC, 20-30 parts of maleic anhydride modified polybutylene terephthalate (maleic anhydride modified PBT) and 15-20 parts of a reinforcing agent. High strength and heat stability are provided through PC, the rigidity and size stability of the material are improved through PBT, the reinforcing agent is dispersed in a phase interface to form a soft-phase toughening area, impact energy is absorbed, crack propagation is prevented, multiple reaction sites form a chemical bond cross-linked structure, and the impact performance and heat resistance are further improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of modified plastics, and particularly relates to PC / PBT modified plastics and a preparation method thereof. BACKGROUND

[0002] Polycarbonate (PC) and polybutylene terephthalate (PBT) are two important members of contemporary engineering plastics, and are widely used in electronic and electrical, automobile industry, household appliances, information communication equipment and many other fields due to their excellent characteristics in mechanical properties, thermal stability, electrical properties and processing properties. However, single variety of resin still has certain limitations in meeting the comprehensive performance requirements of modern industrial products. Therefore, through the means of blending modification, the advantages of two or more polymer materials are complementary, which has become an important development direction to improve the comprehensive performance of engineering plastics. PC is an amorphous thermoplastic plastic, and has excellent impact strength, transparency, dimensional stability and good electrical insulation performance. The shortcomings of PC mainly include poor solvent resistance, limited chemical corrosion resistance, poor flowability and high processing temperature. In addition, although the toughness of PC is excellent, the brittleness of PC significantly increases at low temperature, and there is a risk of stress cracking in long-term use. PBT is a crystalline polyester material, and has excellent heat resistance, wear resistance, good dimensional stability and processing flowability, short molding cycle, and is suitable for high-speed injection molding, especially for manufacturing precision electronic parts. However, the impact performance of PBT itself is low, the brittleness is large, and the hydrolysis easily occurs in a humid environment, which affects the mechanical strength. PC and PBT are blended, the high toughness of PC and the high crystallinity and good flowability of PBT are combined, and a blended material with excellent comprehensive performance is prepared. The PC / PBT blend has high strength and toughness of PC, and also has the easy processability and chemical resistance of PBT, and is a widely used modified plastic system in the electronic and electrical and automobile industries.

[0003] Although PC and PBT have strong complementarity, they face a series of technical challenges in the blending process, mainly including the following points: compatibility problem: PC is an amorphous polymer, and PBT is a semi-crystalline polymer, and there are great differences between the two in molecular structure, polarity, thermal performance and the like, and when directly blended, a phase separation structure is easily formed, resulting in poor interfacial bonding of the blend and a decrease in the mechanical properties of the material. Impact performance is insufficient: the impact performance of PC / PBT blended materials is still difficult to meet the requirements of some structural parts in high-temperature or low-temperature environments, especially the low notched impact strength, and the material is prone to crack propagation and brittle fracture when impacted. Processing stability problem: improper addition of compatibilizers or other additives in the blended material can cause thermal degradation, decomposition bubbles, rough surface of the product and the like, affecting the forming quality of the material and the appearance of the product. SUMMARY

[0004] In view of the above, in order to overcome the defects of the prior art, the present application provides a PC / PBT modified plastic and a preparation method thereof. The present application provides high strength and thermal stability through PC, and improves the rigidity and dimensional stability of the material through PBT; the reinforcing agent is dispersed at the phase interface to form a "soft phase toughening" area to absorb impact energy and prevent crack propagation, and multiple reaction sites form a chemical bond crosslinked structure to further improve the impact performance and heat resistance.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: the present application provides a PC / PBT modified plastic, which comprises the following components in parts by weight: 70-80 parts of polycarbonate (PC), 20-30 parts of maleic anhydride modified polybutylene terephthalate (maleic anhydride modified PBT), and 15-20 parts of a reinforcing agent; Preferably, the raw materials for preparing the maleic anhydride modified PBT comprise the following components in parts by weight: 20-30 parts of terephthalic acid, 12.5-15 parts of 1,4-butanediol, 4-9.25 parts of 3-chloro-1,2-propanediol, and 3.55-8.2 parts of maleic anhydride; Preferably, the raw materials for preparing the reinforcing agent comprise the following components in parts by weight: 10 parts of polypropylene glycol, 2.5-4.0 parts of a diisocyanate compound, 0.8-1.2 parts of 3-allyloxy-1,2-propanediol, 8-12 parts of methyl methacrylate, 3-5 parts of hydroxyethyl acrylate, and 2.5-4.5 parts of a diglycidyl ether compound; Preferably, the diisocyanate compound comprises at least one of 1,5-pentane diisocyanate (PDI), hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), and isophorone diisocyanate (IPDI); Preferably, the diglycidyl ether compound includes at least one of glycerol diglycidyl ether, bisphenol A diglycidyl ether, ethylene glycol diglycidyl ether, bisphenol F diglycidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexanediol diglycidyl ether; Preferably, the preparation method of the reinforcing agent specifically includes the following steps: A1, mixing polypropylene glycol and diisocyanate compound, adding catalyst to the reaction system, increasing the reaction temperature for pre-polymerization, after the reaction, adding 3-allyloxy-1,2-propanediol, increasing the stirring speed and further increasing the reaction temperature for polymerization, after the reaction, washing, drying, and obtaining double bond modified polyurethane; Preferably, in step A1, the added mass of the catalyst is 0.1-0.14% of the mass of polypropylene glycol; Preferably, in step A1, the stirring speed of the pre-polymerization is 300-400 rpm, the reaction temperature of the pre-polymerization is 80-90℃, and the reaction time of the pre-polymerization is 2-3h; Preferably, in step A1, the stirring speed of the polymerization is 600-700 rpm, the reaction temperature of the polymerization is 100-110℃, and the reaction time of the polymerization is 12-18h; A2, dissolving the double bond modified polyurethane prepared in step A1 in DMF, adding methyl methacrylate and hydroxyethyl acrylate, stirring to mix the reaction system uniformly, adding initiator to the reaction system, increasing the reaction temperature to 70-80℃ for polymerization, and obtaining hydroxylated polyurethane after the reaction; Preferably, in step A2, the added mass of the initiator is 0.3-0.4% of the total mass of methyl methacrylate and hydroxyethyl acrylate; Preferably, in step A2, the initiator includes at least one of ammonium persulfate, sodium persulfate, and potassium persulfate; Preferably, in step A2, the stirring speed of the polymerization is 400-600 rpm, the reaction temperature of the polymerization is 70-80℃, and the reaction time of the polymerization is 1-2h; A3, adding a diglycidyl ether compound to the hydroxylated polyurethane reaction system prepared in step A2, adding triethylamine, increasing the reaction temperature for ring-opening reaction, after the reaction, cooling the reaction system to room temperature, washing the reaction system to neutral with saturated sodium bicarbonate aqueous solution, collecting the organic phase, drying the organic phase with anhydrous magnesium sulfate, removing excess reaction solvent by rotary evaporation, and obtaining modified polyurethane particles after granulation; Preferably, in step A3, the mass-volume ratio between the diglycidyl ether compound and triethylamine is 0.2-0.3g / mL; Preferably, in step A3, the reaction temperature of the ring-opening reaction is 100-120℃, and the reaction time of the ring-opening reaction is 2-4h. A4, the modified polyurethane particles prepared in step A3 are mixed with anhydrous ethanol and placed in -25℃ for demulsification treatment, and after the end, drying treatment is carried out in a drying box to obtain a reinforcing agent; Preferably, in step A4, the demulsification treatment time is 18-24h; Preferably, in step A4, the drying treatment temperature is 50-60℃, and the drying treatment time is 12-15h.

[0006] The application also provides a preparation method of PC / PBT modified plastic, which specifically comprises the following steps: S1, terephthalic acid, 1,4-butanediol, and 3-chloro-1,2-propanediol are uniformly mixed, nitrogen gas is introduced, TBT catalyst is added, the reaction temperature is increased for esterification reaction, after the reaction is completed, dibutyltin dilaurate is added, and the reaction temperature is increased for polycondensation reaction under vacuum condition, after the reaction is completed, anhydrous diethyl ether is added for washing, and after drying, PBT-Cl is obtained; Preferably, in step S1, the added mass of the TBT catalyst is 0.5%-1% of the mass of terephthalic acid; Preferably, in step S1, the added mass of the dibutyltin dilaurate is 0.5%-1% of the mass of terephthalic acid; Preferably, in step S1, the reaction temperature of the esterification reaction is 200-220℃, and the reaction time of the esterification reaction is 6-8h; Preferably, in step S1, the reaction temperature of the polycondensation reaction is 250-270℃, and the reaction time of the polycondensation reaction is 6-8h; S2, PBT-Cl prepared in step S1 is dissolved in DMSO, maleic anhydride is uniformly mixed and added, and benzoyl peroxide is added, and the reaction temperature is increased for grafting reaction under nitrogen atmosphere, after the reaction is completed, anhydrous ethanol is added for washing, and after drying, maleic anhydride modified polybutylene terephthalate is obtained; Preferably, in step S2, the added mass of the benzoyl peroxide is 0.2%-0.5% of the mass of maleic anhydride; Preferably, in step S2, the reaction temperature of the grafting reaction is 80-90℃, and the reaction time of the grafting reaction is 4-6h; S3, after the maleic anhydride modified PBT and polycarbonate prepared in step S2 are dried at 120℃ for 6h, the PC / PBT modified plastic is obtained by loading into a twin-screw extruder, adding a reinforcing agent, stirring at a speed of 80-100rpm, increasing the temperature to 250-270℃ for melt blending, extruding and cooling, granulating, drying at 120℃ for 6h, and then injection molding at 250℃.

[0007] The beneficial effects obtained by the present application are as follows: The present application provides a PC / PBT modified plastic and a preparation method thereof. The present application provides high strength and thermal stability by PC, improves the rigidity and dimensional stability of the material by PBT, disperses the reinforcing agent in the phase interface to form a "soft phase toughening" area, absorbs impact energy, prevents crack propagation, forms a chemical bond crosslinking structure at multiple reaction sites to further improve impact performance and heat resistance. In the present application, polypropylene glycol reacts with diisocyanate to form a prepolymer, a flexible segment (polyether structure) is introduced into the structure, which helps to improve the overall flexibility and toughness, 3-allyloxy-1,2-propanediol introduces a double bond, providing active sites for subsequent grafting and crosslinking reaction; the overall prepolymer with a double bond at the end has crosslinking potential and flexibility adjustment effect, methyl methacrylate (PMMA structure) and hydroxyethyl acrylate are introduced into the double bond polyurethane main chain by free radical polymerization, a rigid skeleton and a polar group are introduced, the compatibility and polar group density of the material are improved, which helps to be compatible with the PC / PBT system interface; the crosslinking network formed by the reaction of diglycidyl ether and hydroxyl group improves the structural integrity and heat resistance of the reinforcing agent, and improves the dispersion stability of the reinforcing agent in melt blending and the interfacial crosslinking ability with the matrix; the polyurethane part improves the flexibility and ductility, the double bond and hydroxyl group enhance the reactivity and interfacial bonding force with the PC / PBT matrix, and the microparticulate particles can be uniformly dispersed to form a "soft domain toughening" effect to absorb impact energy. In the present application, an esterification and polycondensation are used to synthesize a polyester containing a halogenated structure (Cl) to improve its polarity and reactivity, functionalize the PBT to create conditions for subsequent grafting reaction, and use a free radical initiator (benzoyl peroxide) to graft maleic anhydride to the PBT chain. Maleic anhydride is a polar monomer that can significantly improve the interfacial compatibility between PBT and PC, and can react with the hydroxyl or amine group in the reinforcing agent after introducing anhydride group to form ester bond / amide bond crosslinking; the grafted PBT has enhanced polarity, improved compatibility with PC, reduced phase separation, improved overall mechanical stability and impact toughness of the modified material, and provides reaction sites and synergistic effect with the reinforcing agent. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 The tensile property results of the PC / PBT plastic prepared in Examples 1-3 and Comparative Examples 1-2 of the present application are shown in the following figure; Figure 2 The impact strength results chart of the PC / PBT plastic prepared for the examples 1-3 and the comparative examples 1-2 of the present application; Figure 3 The SEM image of the PC / PBT modified plastic prepared for the example 1.

[0009] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate the present application and explain the technical scheme of the present application, and do not constitute a limitation on the present application. DETAILED DESCRIPTION

[0010] The technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0011] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by one of ordinary skill in the art. In addition, any method and material similar or equivalent to those described herein can be used in the present application. The preferred implementation methods and materials described herein are only used for demonstration, but cannot limit the content of the present application.

[0012] The experimental methods in the following examples are all conventional methods unless otherwise specified. The experimental materials and strains used in the following examples are all purchased from commercial channels unless otherwise specified.

[0013] The purchase sources of the materials used in the present application are shown as follows: Example 1 The present embodiment provides a PC / PBT modified plastic, which comprises the following components in parts by weight: polycarbonate (PC, brand 02-10R, Zhefeng Da Feng) 70 parts, maleic anhydride modified polybutylene terephthalate (maleic anhydride modified PBT) 30 parts, reinforcing agent 15 parts. The raw materials for preparing the maleic anhydride modified PBT comprise the following components in parts by weight: terephthalic acid 20 parts, 1,4-butanediol 12.5 parts, 3-chloro-1,2-propanediol 4 parts, maleic anhydride 3.55 parts; The raw materials for preparing the reinforcing agent comprise the following components in parts by weight: polypropylene glycol 10 parts, 1,5-pentadiisocyanate 2.5 parts, 3-allyloxy-1,2-propanediol 0.8 parts, methyl methacrylate 10 parts, hydroxyethyl acrylate 5 parts, glycerol diglycidyl ether 3.0 parts; The preparation method of the reinforcing agent specifically comprises the following steps: A1, take polypropylene glycol 10 g and 1, 5-pentane diisocyanate 2.5 g are mixed, 10 mg DBTDL catalyst is added to the reaction system, the reaction temperature is increased to carry out prepolymerization, the stirring speed of prepolymerization is 400 rpm, the reaction temperature of prepolymerization is 90 DEG C, the reaction time of prepolymerization is 3 h, after the reaction, 3-allyloxy-1, 2-propanediol 0.8 g is added, the speed is increased and the reaction temperature is further increased to carry out polymerization, the stirring speed of polymerization is 600 rpm, the reaction temperature of polymerization is 110 DEG C, the reaction time of polymerization is 14 h, after the reaction, washing, drying, the double bond modified polyurethane is obtained; A2, the double bond modified polyurethane prepared in step A1 is dissolved in DMF, methyl methacrylate 10 g and hydroxyethyl acrylate 5 g are added, the reaction system is mixed uniformly after stirring, 45 mg ammonium persulfate is added to the reaction system, the reaction temperature is increased to carry out polymerization, the stirring speed of polymerization is 600 rpm, the reaction temperature of polymerization is 80 DEG C, the reaction time of polymerization is 1 h, after the reaction, the hydroxylated polyurethane is obtained; A3, glycerol diglycidyl ether 3.0 g is added to the hydroxylated polyurethane reaction system prepared in step A2, triethylamine 15 mL is added, the reaction temperature is increased to carry out ring opening reaction, the reaction temperature of ring opening reaction is 120 DEG C, the reaction time of ring opening reaction is 2 h, after the reaction, the reaction system is cooled to room temperature, the reaction system is washed to neutral with saturated sodium bicarbonate aqueous solution, the organic phase is collected, the organic phase is dried with anhydrous magnesium sulfate, the excess reaction solvent is removed by rotary evaporation, and the modified polyurethane particles are obtained after granulation; A4, the modified polyurethane particles prepared in step A3 are mixed with anhydrous ethanol, and are placed in-25 DEG C for demulsification treatment for 18 h, after the end, drying treatment is carried out in the drying box, the drying treatment temperature is 50 DEG C, the drying treatment time is 15 h, and the reinforcing agent is obtained; The embodiment also provides a preparation method of PC / PBT modified plastic, which specifically comprises the following steps: S1, take terephthalic acid 4.0 g, 1, 4-butanediol 2.5 g and 3-chloro-1, 2-propanediol 0.8 g, mix uniformly, introduce flowing nitrogen, add 30 mg TBT catalyst, increase the reaction temperature to carry out esterification, the reaction temperature of esterification is 220 DEG C, the reaction time of esterification is 8 h, after the reaction, add dibutyltin diacetate 30 mg, place in the vacuum condition, increase the reaction temperature to carry out polycondensation, the reaction temperature of polycondensation is 250 DEG C, the reaction time of polycondensation is 8 h, after the reaction, wash with anhydrous ether, dry, and the PBT-Cl is obtained; S2, the PBT-Cl prepared in step S1 is dissolved in DMSO, 0.7g of maleic anhydride is added and mixed uniformly, 3.5mg of benzoyl peroxide is added, the reaction temperature is increased under nitrogen atmosphere to carry out grafting reaction, the grafting reaction temperature is 90℃, the grafting reaction time is 4h, after the reaction is completed, anhydrous ethanol is added for washing, and after drying, maleic anhydride modified PBT is obtained; S3, the maleic anhydride modified PBT 70 parts prepared in step S2 and polycarbonate 30 parts are dried at 120℃ for 6h, then loaded into a double screw extruder, 15 parts of reinforcing agent is added, stirring is carried out at 80rpm, the temperature value is increased to 260℃ for melt blending, extrusion cooling and granulation are carried out, drying is carried out at 120℃ for 6h, and then injection molding is carried out at 250℃ to obtain PC / PBT modified plastic.

[0014] Example 2 The present embodiment provides a PC / PBT modified plastic, which comprises the following components in parts by weight: polycarbonate (PC, brand 02-10R, Zhefeng Da Feng) 80 parts, maleic anhydride modified polybutylene terephthalate (maleic anhydride modified PBT) 20 parts, and reinforcing agent 18 parts. The raw materials for preparing the maleic anhydride modified PBT comprise the following components in parts by weight: terephthalic acid 25 parts, 1,4-butanediol 14 parts, 3-chloro-1,2-propanediol 6 parts, and maleic anhydride 5.5 parts. The raw materials for preparing the reinforcing agent comprise the following components in parts by weight: polypropylene glycol 10 parts, hexamethylene diisocyanate 3.0 parts, 3-allyloxy-1,2-propanediol 1.0 part, methyl methacrylate 8 parts, hydroxyethyl acrylate 4 parts, and bisphenol F diglycidyl ether 2.5 parts. The preparation method of the reinforcing agent specifically comprises the following steps: A1, polypropylene glycol 15g and hexamethylene diisocyanate 3.0g are mixed, 12mg of DBTDL catalyst is added to the reaction system, the reaction temperature is increased to carry out prepolymerization, the stirring speed of the prepolymerization is 400rpm, the reaction temperature of the prepolymerization is 80℃, the reaction time of the prepolymerization is 2h, after the reaction is completed, 3-allyloxy-1,2-propanediol 1.0g is added, the stirring speed is increased and the reaction temperature is further increased to carry out polymerization, the stirring speed of the polymerization is 700rpm, the reaction temperature of the polymerization is 100℃, and the reaction time of the polymerization is 12h, after the reaction is completed, washing and drying are carried out to obtain double bond modified polyurethane; A2, the double bond modified polyurethane prepared in step A1 is dissolved in DMF, 8 g of methyl methacrylate and 4 g of hydroxyethyl acrylate are added, the reaction system is mixed uniformly after stirring, 42 mg of ammonium persulfate is added to the reaction system, the reaction temperature is increased to carry out polymerization reaction, the stirring speed of the polymerization reaction is 400 rpm, the reaction temperature of the polymerization reaction is 75℃, the reaction time of the polymerization reaction is 2 h, after the reaction is completed, a hydroxylated polyurethane is obtained; A3, 2.5 g of bisphenol F diglycidyl ether is added to the hydroxylated polyurethane reaction system prepared in step A2, 10 mL of triethylamine is added, the reaction temperature is increased to carry out ring opening reaction, the reaction temperature of the ring opening reaction is 100℃, the reaction time of the ring opening reaction is 3 h, after the reaction is completed, the reaction system is cooled to room temperature, saturated sodium bicarbonate aqueous solution is added to wash the reaction system to neutral, then the organic phase is collected, the organic phase is dried with anhydrous magnesium sulfate, the excess reaction solvent is removed by rotary evaporation, and the modified polyurethane particles are obtained after granulation; A4, the modified polyurethane particles prepared in step A3 are mixed with anhydrous ethanol, and are placed in a -25℃ environment for demulsification treatment for 24 h, then are placed in a drying box for drying treatment, the drying treatment temperature is 55℃, and the drying treatment time is 12 h, to obtain an enhancer; The embodiment also provides a preparation method of PC / PBT modified plastic, which specifically comprises the following steps: S1, 5.0 g of terephthalic acid, 2.8 g of 1,4-butanediol, and 1.2 g of 3-chloro-1,2-propanediol are uniformly mixed, 50 mg of TBT catalyst is added, and the reaction temperature is increased to carry out esterification reaction, the esterification reaction temperature is 200℃, and the esterification reaction time is 6 h, after the reaction is completed, 50 mg of dibutyltin diacetate is added, and the reaction temperature is increased under vacuum to carry out polycondensation reaction, the polycondensation reaction temperature is 260℃, and the polycondensation reaction time is 7 h, after the reaction is completed, anhydrous ethyl ether is added for washing, and then drying is performed to obtain PBT-Cl; S2, the PBT-Cl prepared in step S1 is dissolved in DMSO, 1.1 g of maleic anhydride is added and uniformly mixed, 3.3 mg of benzoyl peroxide is added, and the reaction temperature is increased to carry out grafting reaction under a nitrogen atmosphere, the grafting reaction temperature is 80℃, and the grafting reaction time is 6 h, after the reaction is completed, anhydrous ethanol is added for washing, and then drying is performed to obtain maleic anhydride modified PBT; S3. After drying 80 parts of maleic anhydride modified PBT and 20 parts of polycarbonate prepared in step S2 at 120°C for 6 hours, they are loaded into a twin-screw extruder, 18 parts of reinforcing agent are added, and the mixture is stirred at 90 rpm. The temperature is increased to 250°C for melt blending, extruded, cooled and granulated, dried at 120°C for 6 hours, and then injection molded at 250°C to obtain PC / PBT modified plastic.

[0015] Example 3 This embodiment provides a PC / PBT modified plastic, which comprises the following components in parts by weight: 75 parts of polycarbonate (PC, grade 02-10R, Zhejiang Tie Dafeng), 25 parts of maleic anhydride modified polybutylene terephthalate (maleic anhydride modified PBT), and 20 parts of reinforcing agent. The raw materials for preparing maleic anhydride-modified PBT include the following components in parts by weight: 30 parts terephthalic acid, 15 parts 1,4-butanediol, 9.25 parts 3-chloro-1,2-propanediol, and 8.2 parts maleic anhydride. The raw materials for preparing the reinforcing agent include the following components in parts by weight: 10 parts of polypropylene glycol, 4.0 parts of lysine diisocyanate, 0.8 parts of 3-allyloxy-1,2-propanediol, 12 parts of methyl methacrylate, 3 parts of hydroxyethyl acrylate, and 4.5 parts of 1,6-hexanediol diglycidyl ether. The preparation method of the reinforcing agent specifically includes the following steps: A1. Mix 20g of polypropylene glycol with 4.0g of lysine diisocyanate. Add 14mg of DBTDL catalyst to the reaction system and raise the reaction temperature to carry out a prepolymerization reaction. The stirring speed of the prepolymerization reaction is 400rpm, the reaction temperature is 90℃, and the reaction time is 2h. After the reaction is completed, add 1.2g of 3-allyloxy-1,2-propanediol, increase the stirring speed and further raise the reaction temperature to carry out a polymerization reaction. The stirring speed of the polymerization reaction is 600rpm, the reaction temperature is 100℃, and the reaction time is 18h. After the reaction is completed, wash and dry to obtain double bond modified polyurethane. A2. Dissolve the double-bond modified polyurethane prepared in step A1 in DMF, add 12g of methyl methacrylate and 3g of hydroxyethyl acrylate, stir to mix the reaction system evenly, add 60mg of ammonium persulfate to the reaction system, raise the reaction temperature to carry out the polymerization reaction, the stirring speed of the polymerization reaction is 500rpm, the reaction temperature of the polymerization reaction is 70℃, the reaction time of the polymerization reaction is 1.5h, after the reaction is completed, hydroxylated polyurethane is obtained; A3、to the hydroxylated polyurethane reaction system prepared in step A2, 1,6-hexanediol diglycidyl ether 4.5 g and triethylamine 13.5 mL were added, the reaction temperature was raised to carry out ring-opening reaction, the reaction temperature of ring-opening reaction was 110℃, the reaction time of ring-opening reaction was 4h, after the reaction was completed, the reaction system was cooled to room temperature, after the reaction system was washed to neutral with saturated sodium bicarbonate aqueous solution, the organic phase was collected, the organic phase was dried with anhydrous magnesium sulfate, the excess reaction solvent was removed by rotary evaporation, and after granulation, modified polyurethane particles were obtained; A4、the modified polyurethane particles prepared in step A3 were mixed with anhydrous ethanol, and were placed in a dry box for drying treatment at 60℃ for 14h to obtain a reinforcing agent; The embodiment also provides a preparation method of PC / PBT modified plastic, and specifically comprises the following steps: S1, 6.0 g of terephthalic acid, 3.0 g of 1,4-butanediol, and 1.85 g of 3-chloro-1,2-propanediol were uniformly mixed, nitrogen was introduced, 30 mg of TBT catalyst was added, and the reaction temperature was raised to carry out esterification reaction, the reaction temperature of esterification reaction was 210℃, the reaction time of esterification reaction was 7h, after the reaction was completed, 30 mg of dibutyltin dilaurate was added, and the reaction temperature was raised under vacuum to carry out polycondensation reaction, the reaction temperature of polycondensation reaction was 270℃, the reaction time of polycondensation reaction was 6h, after the reaction was completed, anhydrous ethyl ether was added for washing, and after drying, PBT-Cl was obtained; S2, the PBT-Cl prepared in step S1 was dissolved in DMSO, 1.65 g of maleic anhydride was uniformly mixed and added, 3.3 mg of benzoyl peroxide was added, and the reaction temperature was raised to carry out grafting reaction under a nitrogen atmosphere, the reaction temperature of grafting reaction was 85℃, the reaction time of grafting reaction was 5h, after the reaction was completed, anhydrous ethanol was added for washing, and after drying, maleic anhydride modified PBT was obtained; S3, the maleic anhydride modified PBT prepared in step S2 was dried at 120℃ for 6h, and then was loaded into a double-screw extruder, 20 parts of reinforcing agent was added, stirring was carried out at a speed of 100 rpm, the temperature was raised to 270℃ to carry out melt blending, extrusion cooling and granulation were carried out, and after drying at 120℃ for 6h, injection molding was carried out at 250℃ to obtain PC / PBT modified plastic.

[0016] Comparative Example 1 The comparative example provides PC / PBT plastic and a preparation method thereof, which is different from example 1 only in that no reinforcing agent is contained in all components, and the remaining components and component contents are the same as those of example 1.

[0017] Comparative Example 2 The present comparative example provides a PC / PBT plastic and a preparation method thereof, which is only different from Example 1 in that the maleic anhydride modified PBT is replaced by PBT in the same weight parts in all components, and the rest of the components and component contents are the same as those in Example 1.

[0018] Comparative Example 3 The present comparative example provides a PC / PBT plastic and a preparation method thereof, which is only different from Example 1 in that the preparation raw material of the reinforcing agent only includes polypropylene glycol and 1,5-pentane diisocyanate, the preparation method of the reinforcing agent only includes step A1, and in step A1, after the prepolymerization reaction is completed, the rotation speed is increased and the reaction temperature is further increased for polymerization reaction to obtain the reinforcing agent, and the rest of the components and component contents are the same as those in Example 1.

[0019] Experimental Example The PC / PBT plastics prepared in Examples 1-3 and Comparative Examples 1-3 are injected into standard tensile samples and impact samples by using a micro plastic machine, and the injection temperature is 265°C. The standard impact sample is punched into a V-shaped notch with a size of 2mm by using an automatic notch sample preparation machine, and is used for mechanical property test after being placed at room temperature for 24h to eliminate stress. 1. The tensile property test is carried out according to GB-T 528-2009 at 25°C and a tensile rate of 50mm / min on a universal material tension machine. Five samples are tested for each sample, and the average value is taken.

[0020] Figure 1 The tensile property results of the PC / PBT plastics prepared in Examples 1-3 and Comparative Examples 1-3 of the present application are shown in the figure. Due to the addition of the reinforcing agent, the PC / PBT plastic presents a ternary blending system, and the tensile strength of the reinforcing agent is lower than that of the PC / PBT binary alloy. After mixing, a three-dimensional crosslinked network is formed, which leads to the improvement of the overall blending system tensile strength.

[0021] 2. The impact property test is carried out according to GB / T 9341-2008 at 25°C. The injection sample is punched into a V-shaped notch by using a notch sample preparation machine, and is tested after being placed at 25°C for 24h. Five samples are tested for each sample, and the average value is taken.

[0022] Figure 2The impact strength results of the PC / PBT plastics prepared in Examples 1-3 and Comparative Examples 1-3 are shown in the figure. With the addition of the reinforcing agent, the solubility parameters of the polyacrylate and PBT, PC are similar, and therefore, the maleic anhydride can have a better interface between the matrix and the rubber particles. The PBT and PC form a homogeneous phase during the extrusion process, and the rubber phase is distributed in the PBT and PC continuous phase in the form of particles, thereby making the entire system exhibit an "island" structure. At the same time, this structure endows the blended system with good impact resistance.

[0023] 3. The heat resistance was tested according to GB / T 1634.2-2019, and the load heat distortion temperature of the PC / PBT plastics prepared in Examples 1-3 and Comparative Examples 1-3 was determined using a D-44149 micro-calorimetric heat distortion instrument. The determination conditions were set as follows: load A (1.82 MPa), heating rate 2 ℃ / min, support span: 100 mm ± 1 mm, and sample thickness 4 mm.

[0024] Figure 3 The heat distortion temperature results of the PC / PBT plastics prepared in Examples 1-3 and Comparative Examples 1-3 are shown in the figure. The load heat distortion temperature of the PC / PBT plastics prepared in Examples 1-3 remained above 95 ℃, while the heat distortion temperature of the PC / PBT plastics prepared in Comparative Example 1 was the lowest, and the heat resistance was poor. The heat resistance of Comparative Examples 2 and 3 was close, but was quite different from that of the examples.

[0025] Although the embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application.

[0026] The above describes the present application and its embodiments, which are not restrictive, and the embodiments shown in the figure are only one of the embodiments of the present application, and the actual application is not limited thereto. In summary, if those of ordinary skill in the art are inspired thereby, without departing from the principles and spirit of the present application, they can not design similar ways and embodiments without creativity, which should all belong to the protection scope of the present application.

Claims

1. A PC / PBT modified plastic, characterized by: The modified plastic comprises the following components in parts by weight: polycarbonate 70-80 parts, maleic anhydride modified polybutylene terephthalate 20-30 parts, reinforcing agent 15-20 parts; the raw materials for preparing the maleic anhydride modified polybutylene terephthalate comprise the following components in parts by weight: terephthalic acid 20-30 parts, 1,4-butanediol 12.5-15 parts, 3-chloro-1,2-propanediol 4-9.25 parts, maleic anhydride 3.55-8.2 parts; the raw materials for preparing the reinforcing agent comprise the following components in parts by weight: polypropylene glycol 10 parts, diisocyanate compound 2.5-4.0 parts, 3-allyloxy-1,2-propanediol 0.8-1.2 parts, methyl methacrylate 8-12 parts, hydroxyethyl acrylate 3-5 parts, diglycidyl ether compound 2.5-4.5 parts; the diisocyanate compound comprises at least one of 1,5-pentane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate; the diglycidyl ether compound comprises at least one of glycerol diglycidyl ether, bisphenol A diglycidyl ether, ethylene glycol diglycidyl ether, bisphenol F diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether.

2. The PC / PBT modified plastic according to claim 1, characterized in that: The preparation method of the reinforcing agent specifically comprises the following steps: A1, mix polypropylene glycol and diisocyanate compound, add a catalyst to the reaction system, increase the reaction temperature for pre-polymerization, after the reaction is completed, add 3-allyloxy-1,2-propanediol, increase the rotation speed and further increase the reaction temperature for polymerization, after the reaction is completed, wash and dry to obtain a double bond modified polyurethane; A2, dissolve the double bond modified polyurethane prepared in step A1 in DMF, add methyl methacrylate and hydroxyethyl acrylate, stir to mix the reaction system uniformly, add an initiator to the reaction system, increase the reaction temperature to 70-80°C for polymerization, after the reaction is completed, obtain a hydroxylated polyurethane; A3, add a diglycidyl ether compound to the hydroxylated polyurethane reaction system prepared in step A2, add triethylamine, increase the reaction temperature for ring-opening reaction, after the reaction is completed, cool the reaction system to room temperature, wash the reaction system to neutral with saturated sodium bicarbonate aqueous solution, collect the organic phase, dry the organic phase with anhydrous magnesium sulfate, remove the excess reaction solvent by rotary evaporation, granulate to obtain modified polyurethane particles; A4, mix the modified polyurethane particles prepared in step A3 with anhydrous ethanol, perform demulsification treatment in -25°C, after the treatment is completed, perform drying treatment in a drying agent to obtain a reinforcing agent.

3. The PC / PBT modified plastic according to claim 2, characterized in that: In step A1, the added mass of the catalyst is 0.1-0.14% of the mass of polypropylene glycol; the stirring speed of the prepolymerization reaction is 300-400 rpm, the reaction temperature of the prepolymerization reaction is 80-90℃, and the reaction time of the prepolymerization reaction is 2-3h; the stirring speed of the polymerization reaction is 600-700 rpm, the reaction temperature of the polymerization reaction is 100-110℃, and the reaction time of the polymerization reaction is 12-18h.

4. The PC / PBT modified plastic according to claim 3, characterized in that: In step A2, the added mass of the initiator is 0.3-0.4% of the total mass of methyl methacrylate and hydroxyethyl acrylate; the initiator includes at least one of ammonium persulfate, sodium persulfate and potassium persulfate; the stirring speed of the polymerization reaction is 400-600 rpm, the reaction temperature of the polymerization reaction is 70-80℃, and the reaction time of the polymerization reaction is 1-2h.

5. The PC / PBT modified plastics according to claim 4, characterized in that: In step A3, the mass-volume ratio between the diglycidyl ether compound and triethylamine is 0.2-0.3 g / mL; the reaction temperature of the ring-opening reaction is 100-120℃, and the reaction time of the ring-opening reaction is 2-4h.

6. The PC / PBT modified plastics according to claim 5, characterized in that: In step A4, the time of demulsification treatment is 18-24h; the temperature of drying treatment is 50-60℃, and the time of drying treatment is 12-15h.

7. A method for producing the PC / PBT modified plastic according to claim 6, characterized by: Specifically comprising the following steps: S1, uniformly mix terephthalic acid, 1,4-butanediol and 3-chloro-1,2-propanediol, introduce flowing nitrogen, add TBT catalyst, increase reaction temperature to perform esterification reaction, after reaction, add dibutyltin dilaurate, place under vacuum condition, increase reaction temperature to perform polycondensation reaction, after reaction, add anhydrous ethyl ether for washing, dry to obtain PBT-Cl; S2, dissolve PBT-Cl prepared in step S1 in DMSO, uniformly mix maleic anhydride, add benzoyl peroxide, increase reaction temperature to perform grafting reaction under nitrogen atmosphere, after reaction, add anhydrous ethanol for washing, dry to obtain maleic anhydride modified polybutylene terephthalate; S3, after drying treatment of maleic anhydride grafted PBT and polycarbonate prepared in step S2 at 120℃ for 6h, load into a double screw extruder, add reinforcing agent, stir at a speed of 80-100 rpm, increase temperature to 250-270℃ to perform melt blending, extrude, cool and granulate, dry at 120℃ for 6h, and then place under injection molding at 250℃ to obtain PC / PBT modified plastic.

8. The method for preparing PC / PBT modified plastic according to claim 7, characterized in that: In step S1, the added mass of the TBT catalyst is 0.5%-1% of the mass of terephthalic acid; the added mass of the dibutyltin dilaurate is 0.5%-1% of the mass of terephthalic acid.

9. The method for preparing PC / PBT modified plastic according to claim 8, characterized in that: In step S1, the reaction temperature of the esterification reaction is 200-220℃, and the reaction time of the esterification reaction is 6-8h.

10. The method for preparing PC / PBT modified plastic according to claim 9, characterized in that: In step S1, the reaction temperature of the polycondensation reaction is 250-270℃, and the reaction time of the polycondensation reaction is 6-8h.

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