CN113999381B

CN113999381B - Copolymerized polycarbonate and preparation method thereof

Info

Publication number: CN113999381B
Application number: CN202111438221.3A
Authority: CN
Inventors: 魏志涛; 曾伟; 王磊; 黎源; 黎雷; 张珏; 李凤闯
Original assignee: Wanhua Chemical Group Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd
Priority date: 2021-11-30
Filing date: 2021-11-30
Publication date: 2023-04-11
Anticipated expiration: 2041-11-30
Also published as: CN113999381A

Abstract

The invention discloses a copolymerized polycarbonate and a preparation method thereof, wherein the copolymerized polycarbonate comprises a polycarbonate chain segment, a polybutadiene acrylonitrile chain segment, a polysiloxane chain segment, a branching group obtained by reacting with a branching agent, and a cyanophenyl end capping group obtained by reacting with an end capping agent. The copolymerized polycarbonate intrinsic flame retardant is excellent, and has good chemical resistance and low-temperature impact resistance.

Description

Copolymerized polycarbonate and preparation method thereof

Technical Field

The invention relates to a copolymerized polycarbonate, in particular to a copolymerized polycarbonate and a preparation method thereof.

Background

Polycarbonate (PC) is a linear thermoplastic resin derived from bisphenols and phosgene or their derivatives. Polycarbonates have many desirable properties such as light transmittance, good impact strength, and high heat distortion temperature, and have wide applications in the fields of automobiles, electronic devices, construction, computers, aerospace, and the like. However, polycarbonates and their blends with vinyl polymers are not inherently nonflammable, and conventional PCs still suffer from relatively poor resistance to wet heat aging, poor solvent resistance, susceptibility to stress cracking upon exposure to solvents, poor impact properties at low temperatures, and the like, limiting their use in low temperature applications, and the like.

Patent CN112898553A discloses an intrinsic flame-retardant copolymerized PC and a preparation method thereof, bisphenol S and a siloxane chain segment are introduced into a conventional PC molecular chain to improve the intrinsic flame-retardant property of the PC, the flame-retardant energy level of the PC can reach UL94V0 (3 mm) at most, but the low-temperature impact resistance and the chemical resistance of the material are to be further improved; CN105849171B discloses a method for preparing a low-smoke and low-heat-release train internal component, wherein a cyanophenol-terminated branched PC, tetrabromobisphenol A copolymerized PC and siloxane PC are synthesized at a polymerization end, and are blended with conventional PC, a flame retardant and other additives according to a certain proportion, so that the flame retardant is separated out and the mechanical property of the material is influenced, namely the comprehensive service performance of the material is influenced.

Disclosure of Invention

In order to solve the technical problems, the invention provides a copolymerized polycarbonate which is excellent in intrinsic flame retardant and has good chemical resistance and low-temperature impact resistance and a preparation method thereof.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

first, a copolycarbonate is provided, the copolycarbonate comprising:

1) A polycarbonate segment of the formula I,

2) A polybutadiene acrylonitrile segment represented by the formula II,

3) Optionally, also comprises a structural chain segment shown in a formula III,

4) Branching groups obtained by reaction with a branching agent of the formula IV,

5) A cyanophenyl end capping group obtained by reaction with an end capping agent shown in formula V,

in formula II, m is an integer selected from 10 to 150, preferably 20 to 60; n is an integer of 10 to 150, preferably 20 to 60; r ₁ Is C1-C6 alkylene, preferably C1-C3 alkylene; r is ₂ Is C1-C6 alkylene, preferably C1-C3 alkylene;

in the formula III, p is selected from an integer of 20 to 150, preferably an integer of 40 to 90;

in the formula IV, T is selected from C1-C20 alkyl, C1-C20 alkoxy groups and C7-C12 aralkyl, S is selected from hydrogen, halogen, nitro, C1-C3 alkyl, C1-C3 alkoxy and C7-C12 aralkyl, and S is an integer of 0-4;

in formula V, Y is selected from halogen, nitro, C1-C3 alkyl, C1-C3 alkoxy, C7-C12 aralkyl, Y is an integer from 0 to 4, C is an integer from 1 to 5, and Y + C is from 1 to 5;

preferably, the weight average molecular weight of the copolycarbonate is 19000 to 56000g/mol, preferably 22000 to 35000g/mol.

In some examples, the copolycarbonate comprises 70 to 99 wt% (e.g., 70%, 75%, 80%, 85%, 90%, 95%, 99%, etc.), preferably 75 to 90 wt%, of the segment of formula I, and 1 to 20 wt% (e.g., 1%, 5%, 9%, 11%, 13%, 16%, 20%, etc.), preferably 5 to 15 wt%, of the segment of formula II; the weight percentage of the segment of formula III is 0-10% (e.g., 0.5%, 1%, 5%, 10%), preferably 5-10%; the branching agents of formula IV are reacted with a branching agent to give a branching group content of 0.1 to 1% (e.g., 0.1%, 0.3%, 0.5%, 0.9%, 1%, etc.), preferably 0.2 to 0.5%, based on the total weight of the copolycarbonate.

The present invention also provides a method for preparing the copolycarbonate as described above, comprising the steps of:

1) Preparing a water phase: mixing bisphenol A, a branching agent shown in a formula IV, a sealing agent shown in a formula V, an alkali metal hydroxide and water, and adding a catalyst after the bisphenol A is completely dissolved to form the water phase;

2) Preparing an oil phase: mixing liquid phosgene with an inert organic solvent in a mixer to prepare phosgene solution; meanwhile, in another mixer, carboxyl-terminated polybutadiene acrylonitrile and optional eugenol-terminated PDMS (PDMS refers to polydimethylsiloxane in the invention) are mixed with an inert organic solvent to prepare a comonomer solution;

3) Polymerization reaction: under the condition of stirring, dropwise adding the prepared phosgene solution and the prepared comonomer solution into a water phase to carry out polymerization reaction to obtain copolymer emulsion, wherein the reaction temperature is 30-35 ℃, and the reaction time is 2-4 hours;

4) And (3) post-treatment: purifying the copolymer emulsion, removing the organic solvent, and collecting to obtain a copolymerized polycarbonate product.

In a most preferred embodiment, the branching agent of formula IV is 1, 1-tris- (4-hydroxyphenyl) ethane; the blocking agent shown as the formula V is p-cyanophenol;

in some examples, in step 1), the molar ratio of bisphenol A, the capping agent of formula V, the alkali metal hydroxide, and water is 1 (0.01-0.03): 2.0-3.0): 25-50, preferably 1 (0.012-0.027): 2.2-3.0): 30-50;

preferably, the branching agent of formula IV is added in an amount of 0.001 to 0.01%, preferably 0.0015 to 0.008% by mass of bisphenol A;

preferably, the alkali metal hydroxide is one or more of potassium hydroxide, sodium hydroxide, lithium hydroxide, cesium hydroxide, preferably sodium hydroxide.

In some examples, the catalyst is added in an amount, in terms of its mole ratio to bisphenol a, of from 0.0001 to 0.006; more preferably 0.001 to 0.005;

preferably, the catalyst is one or more of triethylamine, tetrabutylammonium bromide and tetrabutylammonium chloride, and tetrabutylammonium chloride is preferred.

In some examples, the phosgene solution is added in step 3) in a molar ratio of phosgene to bisphenol A of (1.1-1.4): 1, preferably (1.1-1.3): 1. Preferably, the concentration of the phosgene solution is 1 (5-40), preferably 1 (10-30), based on the weight ratio of phosgene to inert organic solvent.

In some examples, in step 3), the carboxyl-terminated polybutadiene acrylonitrile is added in an amount of 1 (3-99), preferably 1 (3-20) by weight based on the weight ratio of the carboxyl-terminated polybutadiene acrylonitrile to the bisphenol A.

The structural formula of the carboxyl-terminated polybutadiene acrylonitrile is shown as the following formula VI,

wherein m is,n、R ₁ 、R ₂ The definitions of (a) are the same as above. The chemical raw material can be purchased from commercial sources or synthesized according to known published patents or methods in the literature, such as CN104592424A, [ Cao's beads, synthesis of carboxyl-terminated liquid nitrile rubber, henan chemical engineering, 1997 (1): 3]"Rotening, shiguang, research on the Synthesis of carboxyl-terminated nitrile-butadiene liquid rubber petrochemical technology and applications, 1992 (3): 157-161]And the like.

In some examples, in step 3), the eugenol-terminated PDMS is added in an amount of (0-0.14): 1, preferably (0.05-0.14): 1, in terms of its weight ratio to bisphenol a.

The structural formula of the eugenol end-capped PDMS is shown as the following formula VII,

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wherein p is as defined above.

Preferably, the concentration of the comonomer solution is 1 (3-6), preferably 1 (4-5) based on the weight ratio of the comonomers (carboxyl-terminated polybutadiene acrylonitrile + eugenol-terminated PDMS) to the inert organic solvent.

The comonomers employed in the present invention may optionally be prepared by prior published techniques or by commercial monomer synthesis.

In some examples, the inert organic solvent is one or more of dichloromethane, trichloromethane, dichloroethane, trichloroethane, preferably dichloromethane.

In some examples, the pH of the reaction system is maintained at 11 to 12, preferably 11.5 to 11.7, by adjusting the pH of the reaction system with an aqueous alkali metal hydroxide solution during the polymerization reaction in step 3).

Preferably, the stirring rate of the polymerization reaction is from 500 to 800rpm, more preferably from 600 to 800rpm.

In step 4), the post-treatment may be performed by a method conventional in the art, for example: the copolymer emulsion is first oil-water separated, and the oil phase is washed successively with alkali, acid and water for several times to eliminate solvent, crushed and dried to obtain qualified copolymer powder.

The invention has the beneficial effects that:

the carboxyl-terminated polybutadiene acrylonitrile has terminal carboxyl group reacted with the phenolic hydroxyl group of bisphenol A to introduce elastic polybutadiene acrylonitrile chain segment into the copolymerized polycarbonate structure, so that the nitrile group content of PC material is increased, the intrinsic flame retardance of the product is improved, the polymer has excellent chemical resistance and low temperature impact resistance, and the application field of the polycarbonate material is widened. In addition, the invention further improves the intrinsic flame retardance of products by introducing the cyanophenyl end-capping groups, improves the branching degree of the copolymer by introducing the branching agent, improves the anti-dripping performance of the polycarbonate, obtains the copolymerized PC with more excellent comprehensive performance, has good overall cooperativity of molecular structure design, is beneficial to regulating and controlling the molecular weight and the composition of the copolymer, and has good industrial application prospect.

In addition, the preparation method has simple and easy operation steps and mild conditions, and is beneficial to reducing the production cost and improving the production efficiency.

Detailed Description

The present invention is further illustrated by the following specific examples, which are intended to be illustrative of the invention and are not to be construed as limiting the scope of the invention.

The analytical evaluation methods involved in the examples of the present invention or the comparative examples are as follows:

(1) The molecular weight was measured by Gel Permeation Chromatography (GPC) using a Waters 1515 gel permeation chromatograph with tetrahydrofuran as solvent and PS as standard at 30 deg.C for 45min.

(2) Notched Izod impact Strength at-40 ℃ was measured according to the standard test method for Izod impact testing of plastics, specified in ASTM D256-1997.

(3) Flame retardant properties

Flammability was evaluated according to the Underwriter's Laboratory Bulletin 94 protocol entitled "Tests for flexibility of Plastic Materials for Parts in Devices and applications" (ISBN 0-7629-0082-2), version 5, 1996, 10/29, plus all revisions and including 12/2003 revisions. Several ratings may be available based on the rate of burning, the extinguishing time, the ability to resist dripping, and whether the drips are burning. Following this protocol, materials can be classified as UL94 HB, V0, V1, V2, 5VA, and/or 5VB; the invention respectively carries out flame retardance detection on samples with the thickness of 1.5mm and 3.2 mm.

(4) Test for solvent resistance

After a sunscreen cream (Banana Boat) was applied to a test piece for tensile strength test (test piece thickness 3.2 mm) in a 1.0% strain jig according to ASTM D543, the change in appearance was observed and classified into four grades A (no crack), B (crack), C (severe crack) and D (fracture) according to the weight of crack occurrence.

[ PREPARATION EXAMPLES ]

(1) < carboxyl terminated polybutadiene Acrylonitrile >

The carboxyl-terminated polybutadiene acrylonitrile adopted in the embodiment of the invention is prepared by referring to the following method:

(1) adding 3000g of absolute ethyl alcohol into a 5L jacket polymerization reaction kettle with a stirrer, introducing ethylene glycol into the jacket to reduce the temperature of the system to-5 ℃, then adding 3170g of acrylonitrile monomer and 405g of butadiene monomer into the reaction kettle, starting stirring, uniformly mixing, then adding 131g of glutaric acid peroxide into the reaction kettle, slowly raising the temperature of the reaction system to 0 ℃, reacting at 0 ℃ for 30min, further raising the reaction temperature to 10 ℃, reacting for 40min, raising the temperature of the reaction system to room temperature (26 ℃), and adding the reaction liquid into pure water to coagulate to obtain carboxyl-terminated polybutadiene acrylonitrile, which is recorded as LNBR-1. The number of polymerization units m and n of butadiene and acrylonitrile were calculated by nuclear magnetic resonance, and the data are shown in Table 1 below.

(2) Carboxyl-terminated polybutadiene acrylonitrile was prepared in substantially the same manner as in the foregoing method (1) except that the amount of the monomer was adjusted to be different: the amount of acrylonitrile monomer added was 1325g and the amount of butadiene monomer added was 2565g. The carboxyl-terminated polybutadiene acrylonitrile obtained was designated as LNBR-2. The number of polymerized units m and n of butadiene and acrylonitrile, respectively, was calculated by nuclear magnetic resonance and is shown in table 1 below.

(3) Carboxyl-terminated polybutadiene acrylonitrile was prepared in the same manner as in the foregoing method (1) except that the amount of the monomer used was adjusted to be different: the amount of acrylonitrile monomer added was 424g and the amount of butadiene monomer added was 3195g.

The carboxyl-terminated polybutadiene acrylonitrile obtained was designated as LNBR-3. The number of polymerization units m and n of butadiene and acrylonitrile were calculated by nuclear magnetic resonance, and are shown in Table 1 below.

TABLE 1 structural data of carboxyl-terminated polybutadiene Acrylonitrile

Model number	m	n
			LNBR-1	15	140
LNBR-2	95	50
			LNBR-3	145	16

(2) < eugenol-terminated PDMS monomer >

(1) Octamethylcyclotetrasiloxane (1420g, 4.80mol), tetramethyldisiloxane (40.2g, 0.3mol) and clay catalyst Filtrol 20 (23.4g, 1.6 wt%) were charged into a reaction vessel equipped with a stirrer and a thermometer and stirred for 40 minutes to homogenize the material mixture, and then the reaction system was heated up to 50 ℃ at a rate of 5 ℃/min and stirred at this temperature for 3 hours, followed by continuing heating up to 120 ℃ at a rate of 5 ℃/min and vigorously stirring at this temperature for reaction for 5 hours, after which the clay catalyst was removed by filtration. Then, the material after the removal of the clay catalyst was put into a reaction vessel equipped with a stirrer and a thermometer and a mixed solution of eugenol (167.2g, 1.02mol) and karstedt's platinum catalyst (0.67 g) was added dropwise with stirring, followed by stirring at a temperature of 80 ℃ for reaction for 13 hours. Unreacted raw materials were then distilled off at 200 ℃ under reduced pressure to 0.2kPa to obtain eugenol-terminated PDMS monomer in a yield of 99%, and the degree of polymerization of PDMS, which was measured by nuclear magnetism, was 45, and for convenience, was defined as PDMS-45 in the present invention.

(2) Octamethylcyclotetrasiloxane (1420g, 4.80mol), tetramethyldisiloxane (20.1g, 0.3mol), and clay catalyst Filtrol 20 (23.4g, 1.6 wt%) were charged into a reaction vessel equipped with a stirrer and a thermometer and stirred for 40 minutes to homogenize the material mixture, and then the reaction system was heated up to 50 ℃ at a rate of 5 ℃/min and stirred at this temperature for 3 hours, followed by continuing to heat up the temperature of the reaction system to 120 ℃ at a rate of 5 ℃/min and vigorously stirring at this temperature for reaction for 5 hours, after which the clay catalyst was removed by filtration. Then, the material after the removal of the clay catalyst was put into a reaction vessel equipped with a stirrer and a thermometer and a mixed solution of eugenol (167.2g, 1.02mol) and karstedt's platinum catalyst (0.67 g) was added dropwise with stirring, followed by stirring at a temperature of 80 ℃ for reaction for 13 hours. Unreacted raw materials were then distilled off at 200 ℃ under reduced pressure to 0.2kPa to obtain eugenol-terminated PDMS monomer in a yield of 99%, and the degree of polymerization of PDMS, which was measured by nuclear magnetism, was 89, and for convenience, was defined as PDMS-89 in the present invention.

[ example 1 ]

2280g of bisphenol A (BPA), 1000g of sodium hydroxide, 47g of p-cyanophenol, 12.8g of 1, 1-tris- (4-hydroxyphenyl) ethane (THPE) and 7200g of water are added into a mixer protected by nitrogen and mixed uniformly; after complete dissolution, 12.9g of tetrabutylammonium bromide catalyst was added to form the sodium phenolate brine phase;

1139g of liquid phosgene and 22770g of Methylene Chloride (MC) are added into another mixer and are uniformly mixed to form a phosgene solution with the mass concentration of 4.76%; adding 640g of LNBR-2 and 2562g of dichloromethane into a mixer, and uniformly mixing the two to form a carboxyl-terminated polybutadiene acrylonitrile solution with the mass concentration of 20%, wherein the carboxyl-terminated polybutadiene acrylonitrile solution is used as a comonomer solution;

then, the sodium phenolate brine phase is put into a polymerization reactor, the prepared phosgene solution and the comonomer solution are respectively added into the polymerization reactor at the stirring speed of 550rpm, and meanwhile, a sodium hydroxide aqueous solution with the mass concentration of 32% is dripped into the reaction system to keep the pH value of the reaction system at 11.4; and (3) maintaining the temperature of the reaction system at 35 ℃, separating and purifying the reaction system and removing the organic solvent after reacting for 2 hours to prepare the copolymerized polycarbonate.

[ examples 2 to 14 and comparative examples 1 to 3 ]

A copolycarbonate was prepared in substantially the same manner as in example 1 except that the amount of the raw material was changed (as shown in Table 1). In each of the examples and comparative examples, liquid phosgene, carboxyl-terminated polybutadiene acrylonitrile and eugenol-terminated PDMS monomers were added, and the mass concentrations of the prepared solutions were maintained at 4.76%, 20% and 20%, respectively.

TABLE 2 feeding parameters of examples and comparative examples

The physical and chemical properties of the copolycarbonates prepared in the examples and comparative examples were measured to obtain a Wanhua chemical polycarbonate

As a blank control, the test results are shown in table 3:

table 3, examples and comparative examples Performance test results

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The comparison of the data shows that compared with the conventional PC, the intrinsic flame retardant property, the chemical resistance and the low-temperature impact resistance of the copolymerized polycarbonate are superior to those of the conventional PC, and polybutadiene acrylonitrile chain segments with excellent performance, cyano-phenol groups and groups from branching agents are introduced into the polycarbonate chain segments, so that the performance of the polycarbonate is effectively improved, and the application field of the material is widened.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and additions can be made without departing from the method of the present invention, and these modifications and additions should also be regarded as the protection scope of the present invention.

Claims

1. A copolymeric polycarbonate, wherein said copolymeric polycarbonate comprises:

1) A polycarbonate segment of the formula I,

2) A polybutadiene acrylonitrile segment of the formula II,

4) A branching group obtained by reaction with a branching agent of the formula IV,

in the formula II, m is an integer of 10-150; n is an integer of 10 to 150; r ₁ Is C1-C6 alkylene; r ₂ Is C1-C6 alkylene;

in the formula III, p is an integer of 20-150;

the weight average molecular weight of the copolymerized polycarbonate is 19000-56000g/mol, and in the copolymerized polycarbonate, the weight percentage of the chain segment shown in the formula I is 70-99%, and the weight percentage of the chain segment shown in the formula II is 2-20%; the weight percentage of the chain segment shown in the formula III is 0-10%; the branching group content obtained by reaction with the branching agent of formula IV is 0.1-1% by weight based on the total weight of the copolycarbonate.

2. The copolycarbonate of claim 1, wherein in formula ii, m is selected from the group consisting of integers ranging from 20 to 60; n is an integer of 20 to 60; r ₁ Is C1-C3 alkylene; r ₂ Is C1-C3 alkylene.

3. The copolycarbonate of claim 1, wherein in formula iii, p is selected from an integer of 40 to 90.

4. The copolycarbonate of claim 1, wherein the weight average molecular weight of the copolycarbonate is between 22000 and 35000g/mol.

5. The copolycarbonate according to claim 1, wherein the weight percentage of the segment represented by formula I is 75 to 90% and the weight percentage of the segment represented by formula ii is 5 to 15%; the weight percentage of the chain segment shown in the formula III is 5-10%; the branching agent of formula IV is reacted with a branching agent to obtain a branching group content of 0.2 to 0.5% by weight based on the total weight of the copolycarbonate.

6. A method for preparing the copolymeric polycarbonate of any one of claims 1 to 5, comprising the steps of:

2) Preparing an oil phase: mixing liquid phosgene with an inert organic solvent in a mixer to prepare phosgene solution; simultaneously, in another mixer, mixing carboxyl-terminated polybutadiene acrylonitrile and optional eugenol-terminated PDMS with an inert organic solvent to prepare a comonomer solution;

7. The method of claim 6, wherein in step 1), the molar ratio of bisphenol A, the end-capping reagent of formula V, the alkali metal hydroxide, and water is 1 (0.01-0.03): (2.0-3.0): 25-50).

8. The method of claim 7, wherein in step 1), the molar ratio of bisphenol A, the end-capping reagent of formula V, the alkali metal hydroxide, and water is 1 (0.012-0.027) (2.2-3.0): (30-50).

9. The method of claim 7, wherein said branching agent of formula IV is added in an amount of 0.001 to 0.01% by mass based on the mass of bisphenol A.

10. The method of claim 9, wherein the branching agent of formula iv is added in an amount of 0.0015 to 0.008% by mass based on the mass of bisphenol a.

11. The method of claim 7, wherein the alkali metal hydroxide is one or more of potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide.

12. The method of claim 7, wherein the catalyst is added in an amount of 0.0001 to 0.006 mol ratio to bisphenol A.

13. The method of claim 12, wherein the catalyst is added in a molar ratio of 0.001 to 0.005.

14. The method of claim 12, wherein the catalyst is one or more of triethylamine, tetrabutylammonium bromide and tetrabutylammonium chloride.

15. The method of claim 6, wherein the phosgene solution is added in a molar ratio of phosgene to bisphenol A of (1.1-1.4): 1 in step 3).

16. The method of claim 15, wherein the phosgene solution is added in a molar ratio of phosgene to bisphenol A of (1.1-1.3): 1 in step 3).

17. The method of claim 15, wherein the carboxyl-terminated polybutadiene acrylonitrile is added in a weight ratio of 1 (3-99) to bisphenol A in step 3).

18. The method of claim 17, wherein the carboxyl-terminated polybutadiene acrylonitrile is added in a weight ratio of 1 (3-20) to bisphenol A in step 3).

19. The method of preparing copolycarbonate according to any of claims 15 to 18, wherein the eugenol-terminated PDMS in step 3) is added in a weight ratio to bisphenol a of (0-0.14): 1.

20. The method of claim 19, wherein in step 3), the eugenol-terminated PDMS is added in a weight ratio of (0.05-0.14): 1.

21. The method of any one of claims 6-18, wherein the inert organic solvent is one or more of dichloromethane, trichloromethane, dichloroethane, and trichloroethane.

22. The method for preparing a copolymeric polycarbonate of any one of claims 6 to 18, wherein the pH of the reaction system is adjusted to 11 to 12 by an aqueous alkali metal hydroxide solution during the polymerization in step 3).