Polycarbonate copolymer and preparation method thereof

Abstract

The invention relates to a polycarbonate material and a preparation method thereof. Specifically, a molecular chain of the copolymer contains a polysiloxane chain segment and a polyphenyl ether chain segment. The polycarbonate copolymer has excellent low-temperature impact resistance, chemical resistance and high hardness. According to the invention, an interface phosgene continuous process is adopted, the polysiloxane chain segment, the polyphenyl ether chain segment and the polycarbonate oligomer are subjected to copolycondensation under the action of the catalyst for preparation, the operation is simple, the realization is easy, and the method can be used in industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and provides a polycarbonate copolymer and a preparation method thereof. Specifically, it relates to a novel polycarbonate copolymer containing siloxane segments and polyphenylene ether segments in the molecular chain and a preparation method thereof. Background Art

[0002] Polycarbonate (PC) is a high molecular polymer containing carbonate bonds in the molecular chain, which can be divided into aliphatic, alicyclic, aliphatic-aromatic and aromatic polycarbonates. Among them, aromatic polycarbonates have excellent mechanical properties, heat resistance, impact toughness, electrical insulation and light transmittance, low creep resistance and water absorption, good dimensional stability, and excellent dielectric properties. They can be used as a thermoplastic engineering plastic and are widely used in the fields of automobiles, electronic devices, construction, office supplies, optical discs, sports equipment, healthcare, computers, aerospace, etc. However, ordinary PC also has certain defects. For example, its inherent flame retardancy is relatively poor (3mm V2), its solvent resistance is poor, stress cracking is easy to occur after touching the solvent, and its impact performance at low temperature is poor, which limits its application in low-temperature places. In order to broaden its application fields, it needs to be modified.

[0003] CN117887057A discloses a scratch-resistant isosorbide-based polycarbonate material and a preparation method thereof. This method uses a phenolic double-active-site ionic liquid catalyst, uses dimethyl carbonate (DMC) and isosorbide (ISB) as raw materials, and 1,4-phenylenedimethanol (PDM) as a copolymer diol monomer to obtain a copolymer-modified isosorbide-based polycarbonate by transesterification melt polycondensation. The low-temperature toughness and chemical resistance of this polycarbonate material need to be improved; for a polycarbonate resin, its molded product and its film proposed in CN103154082A, since it contains units derived from isosorbide and units derived from an o-methyl-substituted aromatic bisphenol in a specified ratio as its constituent components, it has excellent heat resistance, high surface hardness and excellent moldability, but the material is brittle and its chemical resistance is not mentioned; CN119431802A discloses a polycarbonate-polysiloxane copolymer and a preparation method and application thereof, and the scratch resistance of the material has not been improved.

[0004] In summary, it is necessary to improve the chemical resistance, impact resistance, surface hardness (scratch resistance) of polycarbonate resin, make up for the shortcomings of conventional polycarbonate, and broaden the application fields of polycarbonate materials. Summary of the Invention

[0005] One of the purposes of the present invention is to provide a polycarbonate copolymer, and the polycarbonate copolymer at least contains the following three structures:

[0006] (1) A polycarbonate segment of the following formula (I), and

[0007]

[0008] (2) The polyphenylene ether chain segment represented by the following formula (II), and

[0009]

[0010] (3) The polysiloxane chain segment represented by the following formula (III),

[0011]

[0012] wherein, in the said formula (II), the sum of p and q is selected from integers of 5 to 50, preferably integers of 10 to 40;

[0013] In the said formula (III), n is an integer between 20 and 150, preferably an integer between 40 and 90.

[0014] The weight-average molecular weight of the polycarbonate copolymer is 18,000 to 50,000 g / mol, preferably 22,000 to 35,000 g / mol; and in the structure of the polycarbonate copolymer, the weight percentage of the polycarbonate chain segment of structure (I) is 80 - 95%, preferably 85% - 95%, the weight percentage of the polyphenylene ether chain segment of structure (II) is 1 - 10%, preferably 4% - 8%; the weight percentage of the polysiloxane chain segment shown in structure (III) is 5 - 20%, preferably 5% - 15%.

[0015] The second object of the present invention is to provide a preparation method of a polycarbonate copolymer, which comprises the following steps:

[0016] (1) Solution preparation: Dissolve bisphenol A in an aqueous solution of alkali metal hydroxide to obtain a bisphenol A phenolate solution; dissolve eugenol-terminated polysiloxane monomer and terminal phenol group polyphenylene ether monomer in an inert organic solvent respectively to prepare a comonomer solution; dissolve a capping agent in an inert organic solvent to prepare a capping agent solution; dissolve a catalyst in an inert organic solvent to prepare a solution, and dissolve alkali metal hydroxide in water to prepare an alkali metal hydroxide solution;

[0017] (2) Polymerization reaction: Continuously add a certain proportion of phosgene, bisphenol A phenolate solution, eugenol-capped polydimethylsiloxane monomer solution, phenol-terminated polyphenylene ether monomer solution, inert organic solvent, and alkali metal hydroxide solution to the primary polymerization reactor, and carry out a photochemical reaction while maintaining the pH of the reaction solution between 11 and 12; After reacting for a period of time, continuously transfer the oligomer emulsion in the primary reactor to the secondary reactor, and at the same time continuously add a capping agent solution to the secondary reactor. After reacting for a period of time, continuously transfer the polymer emulsion in the secondary reactor to the tertiary reactor, and continuously add a catalyst solution to the tertiary reactor. Carry out polycondensation reaction in the tertiary reactor. After reacting for a period of time, transfer the polymer solution to the quaternary reactor. After staying in the quaternary reactor for a period of time, continuously transfer the polymer solution to the polymer solution storage tank;

[0018] (3) Post-treatment: Purify the copolymer polymerization solution prepared in step (2) and remove the organic solvent to obtain the polycarbonate copolymer.

[0019] In the described preparation method,

[0020] The alkali metal hydroxide is selected from one or more of potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, and preferably sodium hydroxide;

[0021] The capping agent is selected from one or more of phenol, p-cumylphenol, p-methylphenol, p-isopropylphenol, p-tert-butylphenol, and p-cyanophenol, and preferably p-tert-butylphenol and p-cyanophenol;

[0022] The catalyst is selected from one or more of triethylamine, tetrabutylammonium bromide, and tetrabutylammonium chloride, and preferably triethylamine;

[0023] The concentration of BPA in the bisphenol A phenolate solution is 150-200 g / L, preferably 160-170 g / L;

[0024] The concentration of the polysiloxane monomer solution is 10-20 wt%; the concentration of the catalyst solution is 1-10 wt%, preferably 2-5 wt%;

[0025] The concentration of the polyphenylene ether monomer solution capped with phenolic hydroxyl is 10-20 wt%, preferably 10-15 wt%;

[0026] The concentration of the capping agent solution is 10-20 wt%, preferably 10-15 wt%;

[0027] The concentration of the alkali metal hydroxide solution is 25-40 wt%, preferably 30-35 wt%;

[0028] The inert organic solvent is selected from methylene chloride, chloroform, dichloroethane, trichloroethane, and preferably methylene chloride;

[0029] The molar ratio of phosgene to bisphenol A is (1.01 - 1.3):1, preferably (1.1 - 1.15):1;

[0030] The molar ratio of bisphenol A to the capping agent is 20 - 40:1, preferably 27 - 30:1;

[0031] The addition amount of the inert organic solvent is such that the solid content of the reaction solution is 10 - 20%, preferably 15 - 18%;

[0032] The structural formula of the phenol - terminated polyphenylene ether monomer is as shown in Formula Ⅳ below,

[0033]

[0034] Among them, the definitions of p and q in Formula Ⅳ are the same as those in Formula (Ⅱ) above.

[0035] The structural formula of the polyorganosiloxane monomer is as shown in Formula Ⅴ below,

[0036]

[0037] Among them, the definition of n in Formula Ⅴ is the same as that in Formula (Ⅲ) above;

[0038] The comonomers used in the present invention can optionally be prepared by existing publicly available technologies or directly use commercial monomers;

[0039] When carrying out the polymerization reaction, the residence time in each reactor is 10 - 30 min, preferably 10 - 15 min; the pH of the reaction system is 11 - 12, preferably 11.5 - 11.7;

[0040] In step (3), the post - treatment adopts conventional methods in the art. For example: the copolymer emulsion is first subjected to oil - water separation, and the oil phase is successively subjected to alkali washing, acid washing, and multiple water washings. After water washing, the solvent in the oil phase is removed, and after pulverization and drying, qualified powder is obtained.

[0041] The beneficial effects of the present invention are as follows:

[0042] The polycarbonate copolymer prepared by the present invention improves the chemical resistance, low - temperature impact resistance, and scratch resistance of the polycarbonate material, broadens the application field of the polycarbonate material, the molecular weight and composition of the prepared copolymer can be regulated, and the method has simple steps, is convenient for industrial implementation, and has good industrial application prospects. Specific embodiments

[0043] To better understand the technical solution of the present invention, the content of the present invention will be further elaborated below in conjunction with embodiments, but the content of the present invention is not limited to the following embodiments only.

[0044] The analysis and evaluation methods involved in the examples or comparative examples are as follows:

[0045] (1) The molecular weight was tested by gel permeation chromatography (GPC) method. A gel permeation chromatograph of model Waters1515 was used for testing. The solvent was tetrahydrofuran, PS was the standard sample, the temperature was 30 °C, and the time was 45 min;

[0046] (2) The Izod impact performance was determined according to the standard test method for detecting the Izod impact performance of plastics specified in ASTM D256-1997;

[0047] (3) Pencil hardness test: ISO 15184, the load was 7.5 N;

[0048] (4) Solvent resistance performance test

[0049] According to ASTM D543, after applying sunscreen (Banan Boat) to the test piece for tensile strength test (test piece thickness 3.2 mm) with a 1.0% strain fixture, the appearance change was observed, and it was divided into four grades: A (no crack), B (crack), C (severe crack), and D (fracture) according to the severity of crack occurrence;

[0050] The comonomers used in the examples

[0051] (1) <Phenol-terminated polyphenylene ether monomer>

[0052] The phenol-terminated polyphenylene ether monomer can be a commercial monomer or can be prepared by referring to the published literature, such as CN101044187B, CN101326215B, CN118027390A, etc.;

[0053] The monomer used in the example was a commercial monomer with the trade name SA-90, and the sum of p and q was 21;

[0054] (2) <Eugenol-terminated polyorganosiloxane monomer>

[0055] The eugenol-terminated PDMS monomer can be prepared by referring to the published literature or can be purchased as a commercial product.

[0056] The preparation method is as follows: Octamethylcyclotetrasiloxane (1420 g, 4.80 mol), tetramethyldisiloxane (40.2 g, 0.3 mol) and clay catalyst Filtrol 20 (23.4 g, 1.6 wt%) were added to a reaction kettle equipped with a stirrer and a thermometer and stirred for 40 minutes to make the material mixture uniform. Then, the reaction system was heated to 50 °C at a rate of 5 °C / min and stirred at this temperature for 3 hours. Subsequently, the temperature of the reaction system was continuously heated to 120 °C at a rate of 5 °C / min and vigorously stirred and reacted at this temperature for 5 hours. After that, the clay catalyst was removed by filtration. Then, the material after removing the clay catalyst was put into a reaction kettle equipped with a stirrer and a thermometer, and a mixed solution of eugenol (167.2 g, 1.02 mol) and karstedt platinum catalyst (0.67 g) was added dropwise at a rate of 20 g / min under stirring. After that, the reaction was stirred at 80 °C for 13 hours. Subsequently, the unreacted raw materials were removed by distillation under reduced pressure to 0.2 kPa at 200 °C to obtain eugenol-terminated polysiloxane with a yield of 99%. The degree of polymerization of PDMS detected by NMR was 48, which was defined as PDMS-48 for convenience in this article;

[0057] Under other unchanged conditions, by changing the amount of tetramethyldisiloxane, a monomer with a degree of polymerization of 89 of siloxane was prepared, which was defined as PDMS-89 for convenience in this article.

[0058] Preparation method of the examples:

[0059] The preparation methods in the following examples are the same, only the feeding data are changed;

[0060] (1) Prepare solutions: The concentration of BPA is 170 g / L; the concentration of the polydimethylsiloxane monomer solution is 15%; the concentration of the triethylamine solution is 5%; the concentration of the p-tert-butylphenol solution is 11%; the concentration of the sodium hydroxide solution is 32%; the solid content of the polycondensation reaction solution is 16%;

[0061]

[0062]

[0063] (2) Polymerization reaction: According to the feeding ratio shown in the above table, phosgene, BPA sodium phenoxide solution, phenol-terminated polyphenylene ether monomer solution, PDMS monomer solution, dichloromethane, and sodium hydroxide solution are continuously added to the primary polymerization reactor. Maintain the pH of the reaction solution at 12 and the reaction temperature at 30 °C, and carry out the photochemical reaction in the primary polymerization reactor; after 10 minutes of reaction, continuously transfer the oligomer emulsion in the primary polymerization reactor to the secondary polymerization reactor, and at the same time add the capping agent solution to carry out the copolymerization reaction; after 10 minutes of reaction residence, continuously transfer the reaction solution to the tertiary polymerization reactor, and at the same time continuously add triethylamine solution to the tertiary polymerization reactor to carry out the polycondensation reaction. After 10 minutes of reaction, transfer the polymer solution to the quaternary polymerization reactor. After staying in the quaternary polymerization reactor for 10 minutes, continuously transfer the polymer solution to the copolymer solution storage tank;

[0064] (3) Post-treatment: Purify the copolymer solution prepared in step (2) and remove the organic solvent to obtain the product;

[0065] The performance tests of the above examples and comparative examples are shown in the following table:

[0066]

[0067]

[0068] From the comparison of the above data, it can be seen that the polycarbonate copolymer prepared by the present invention has excellent low-temperature impact resistance, chemical resistance and high hardness. The polycarbonate copolymer prepared by the present invention effectively improves the performance of polycarbonate and broadens the application field of the material.

[0069] Those skilled in the art can understand that under the teaching of this specification, some modifications or adjustments can be made to the present invention. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A polycarbonate copolymer, comprising at least the following three structures: (1) a polycarbonate segment of the following formula (I), and (2) a polyphenylene ether segment represented by the following formula (II), and (3) a polysiloxane segment of the following formula (III), in, In the formula (II), the sum of p and q is selected from an integer of 5 to 50, preferably an integer of 10 to 40; In the formula (III), n is an integer between 20 and 150, preferably an integer between 40 and 90.

2. The polycarbonate copolymer according to claim 1, characterized in that The weight average molecular weight of the polycarbonate copolymer is 18000-50000 g / mol, preferably 22000-35000 g / mol; and / or, in the polycarbonate copolymer structure, the weight percentage of the polycarbonate segment of structure (I) is 80-95%, preferably 85%-95%, the weight percentage of the polyphenylene ether segment of structure (II) is 1-10%, preferably 4%-8%; the weight percentage of the polysiloxane segment shown in structure (III) is 5-20%, preferably 5%-15%.

3. The method for preparing a polycarbonate copolymer according to claim 1 or 2, characterized in that: The following steps are involved: (1) Solution preparation: dissolving bisphenol A in an aqueous solution of an alkali metal hydroxide to obtain a bisphenol A sodium salt solution; Dissolving eugenol-terminated polysiloxane monomer and phenol-terminated polyphenylene ether monomer in an inert organic solvent to prepare a comonomer solution; dissolving a capping agent in an inert organic solvent to prepare a capping agent solution; dissolving a catalyst in an inert organic solvent to prepare a solution; and dissolving an alkali metal hydroxide in water to prepare an alkali metal hydroxide solution; (2) Polymerization reaction: continuously adding a certain proportion of phosgene, bisphenol A sodium salt solution, eugenol-terminated polydimethylsiloxane siloxane monomer solution, terminal phenol polyphenylene ether monomer solution, inert organic solvent, and alkali metal hydroxide solution to a primary polymerization reactor, maintaining the pH of the reaction solution between 11 and 12 for photochemical reaction; after a period of reaction, continuously transporting the oligomer emulsion in the primary reactor to the secondary reactor, and continuously adding the end-capping agent solution to the secondary reactor; after a period of reaction, continuously transporting the polymer emulsion in the secondary reactor to the tertiary reactor, and continuously adding the catalyst solution to the tertiary reactor, and performing polycondensation reaction in the tertiary reactor; after a period of reaction, transporting the polymer solution to the quaternary reactor; after a period of reaction, continuously transporting the polymer solution to the quaternary reactor; after a period of stay in the quaternary reactor, continuously transporting the polymer solution to the polymer solution storage tank; (3) Post-treatment: Purify the copolymer polymerization solution prepared in step (2) and remove the organic solvent to obtain a polycarbonate copolymer.

4. The preparation method according to claim 3, characterized in that: The alkali metal hydroxide is selected from one or more of potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, preferably sodium hydroxide; and / or the end-capping agent is selected from one or more of phenol, p-cumylphenol, p-methylphenol, p-isopropylphenol, p-tert-butylphenol, and p-cyanophenol, preferably p-tert-butylphenol and p-cyanophenol; and / or the catalyst is selected from one or more of triethylamine, tetrabutylammonium bromide, and tetrabutylammonium chloride, preferably triethylamine.

5. The preparation method according to claim 3 or 4, characterized in that: The concentration of BPA in the bisphenol A sodium salt solution is 150-200 g / L, preferably 160-170 g / L; and / or, the concentration of the polysiloxane monomer solution is 10-20 wt %; the concentration of the catalyst solution is 1-10 wt %, preferably 2-5 wt %; and / or, the concentration of the phenolic hydroxyl-terminated polyphenylene ether monomer solution is 10-20 wt %, preferably 10-15 wt %.

6. The preparation method according to any one of claims 3 to 5, characterized in that: The concentration of the capping agent solution is 10-20wt%, preferably 10-15wt%; and / or the concentration of the alkali metal hydroxide solution is 25-40wt%, preferably 30-35wt%; and / or the inert organic solvent is selected from dichloromethane, chloroform, dichloroethane, trichloroethane, preferably dichloromethane.

7. The preparation method according to any one of claims 3 to 6, characterized in that: The molar ratio of phosgene to bisphenol A is (1.01-1.3):1, preferably (1.1-1.15):1; and / or, the molar ratio of bisphenol A to the end-capping agent is 20-40:1, preferably 27-30:1; and / or, the amount of the inert organic solvent added is such that the solid content of the reaction solution is 10-20%, preferably 15-18%.

8. The preparation method according to any one of claims 3 to 7, characterized in that: The structural formula of the phenol-terminated polyphenylene ether monomer is shown in the following formula IV: Wherein, the definitions of p and q in formula IV are the same as those in formula (II) above.

9. The preparation method according to any one of claims 3 to 8, characterized in that: The structural formula of the polyorganosiloxane monomer is shown in Formula V below: Wherein, the definition of n in formula V is the same as that in formula (III) above.

10. The preparation method according to any one of claims 3 to 9, characterized in that: During the polymerization reaction, the residence time in each reactor is 10 to 30 minutes, preferably 10 to 15 minutes; the pH of the reaction system is 11 to 12, preferably 11.5 to 11.7.

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