阅读说明：本技术 一种硅氧烷共聚碳酸酯的制备方法 (Preparation method of siloxane copolycarbonate ) 是由 李�诚 李强 隋东武 张怀强 王晓东 王玉彬 高俊民 潘勇军 于 2020-06-08 设计创作，主要内容包括：本发明涉及一种硅氧烷共聚碳酸酯的制备方法,该方法包括：工序A：溶有至少一种双酚化合物的碱金属氢氧化物水溶液、光气、惰性有机溶剂,混合进行反应,分离反应得到的两相溶液有机相和含有双酚化合物的碱金属氢氧化物水溶液；工序B：工序A得到的有机相与硅氧烷,在有催化剂的条件下进行混合反应,任选加入碱金属氢氧化物水溶液,得到硅氧烷-聚碳酸酯中间体溶液；工序C：工序B得到的硅氧烷-聚碳酸酯溶液与工序A得到的含有双酚化合物的碱金属氢氧化物水溶液合并,加入封端剂、碱金属氢氧化物水溶液,任选加入催化剂,混合完成反应,得到硅氧烷共聚碳酸酯。所制备共聚物具有优异的低温抗冲性能和透明性,同时在工艺经济性上更有优势。(The invention relates to a method for preparing siloxane copolycarbonate, which comprises the following steps: step A: mixing an aqueous alkali metal hydroxide solution in which at least one bisphenol compound is dissolved, phosgene and an inert organic solvent for reaction, and separating a two-phase solution organic phase obtained by the reaction and an aqueous alkali metal hydroxide solution containing the bisphenol compound; and a step B: mixing the organic phase obtained in the step A and siloxane in the presence of a catalyst for reaction, and optionally adding an alkali metal hydroxide aqueous solution to obtain a siloxane-polycarbonate intermediate solution; and a step C: and (C) combining the siloxane-polycarbonate solution obtained in the step (B) with the alkali metal hydroxide aqueous solution containing the bisphenol compound obtained in the step (A), adding an end-capping reagent and the alkali metal hydroxide aqueous solution, and optionally adding a catalyst, and mixing to complete the reaction to obtain the siloxane copolycarbonate. The prepared copolymer has excellent low-temperature impact resistance and transparency, and has more advantages in process economy.)

1. A method of making a siloxane copolycarbonate, the method comprising:

step A: mixing an aqueous alkali metal hydroxide solution in which at least one bisphenol compound is dissolved, phosgene, and an inert organic solvent to react, and separating the resulting two-phase solution to obtain an organic phase containing a polycarbonate oligomer and an aqueous alkali metal hydroxide solution containing a bisphenol compound, respectively;

and a step B: mixing the organic phase obtained in the step A and siloxane, preferably siloxane shown in a formula (I), in the presence of a catalyst for reaction, and optionally adding an alkali metal hydroxide aqueous solution to make the system alkaline to obtain a siloxane-polycarbonate intermediate solution;

wherein p is an average value of 1 to 100, R₁Is a single bond or C1-C6 alkylene, R₂Is C1-C6 alkyl or alkoxy;

and a step C: and (C) combining the siloxane-polycarbonate solution obtained in the step (B) with the alkali metal hydroxide aqueous solution containing the bisphenol compound obtained in the step (A), adding an end-capping reagent and the alkali metal hydroxide aqueous solution, and optionally adding a catalyst, and mixing to complete the reaction to obtain the siloxane copolycarbonate.

2. The process according to claim 1, wherein the molecular weight of the polycarbonate oligomer in the organic phase separated in step A is 1000-; the molar ratio of acid chloride to the terminal group is 80 to 100%, preferably 90% or more, more preferably 95% or more.

3. The process according to claim 1 or 2, wherein the aqueous solution separated in step a has a bisphenol compound content of 7 to 50g/L, preferably 10 to 45g/L, more preferably 15 to 40 g/L; and/or, after the reaction in the step C is finished, the content of the water phase bisphenol compound is 0-5 g/L.

4. A process according to any one of claims 1 to 3, characterised in that the degree of polymerisation p of the siloxane is an average value of from 20 to 60 and the proportion of siloxane segments by weight of the finally obtained siloxane copolycarbonate is from 1 to 30 wt%, preferably from 2 to 20 wt%, more preferably from 3 to 10 wt%.

5. A method according to any one of claims 1 to 4, wherein the bisphenol compound is selected from the group consisting of 2, 2-bis (4-hydroxyphenyl) propane, 1-bis (4-hydroxyphenyl) -1-phenylethane, 4 '-dihydroxydiphenylmethane, 1-bis (3-methyl-4-hydroxyphenyl) cyclohexane, 1-bis (4-hydroxyphenyl) -3,3, 5-trimethylcyclohexane, 9-bis (4-hydroxyphenyl) fluorene, 9-bis (3-methyl-4-hydroxyphenyl) fluorene, 4' -dihydroxybiphenyl in one or more combinations, preferably 2, 2-bis (4-hydroxyphenyl) propane; and/or the concentration of the bisphenol compound in the aqueous alkali metal hydroxide solution is from 5 to 30% by weight, preferably from 12 to 25% by weight. The molar ratio of alkali metal hydroxide to bisphenol compound is 2.0-3.5: 1, preferably 2.01-2.5: 1.

6. the process according to any one of claims 1 to 5, wherein in step A, the molar ratio of phosgene to bisphenol compound is 1 to 1.2: 1, preferably 1.01 to 1.15: 1.

7. the process according to any one of claims 1 to 6, wherein in step B or C, the catalyst is one or more selected from triethylamine, tributylamine, trioctylamine, N-ethylpiperidine, N-methylpiperidine, N-isopropylpiperidine, N-N-propylpiperidine, tetrabutylammonium, tributylbenzylammonium, tetraethylammonium hydroxide, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium hydrogen sulfate, tetraethylammonium tetrafluoroborate, preferably triethylamine; the amount of the catalyst to be used is 0.01 to 10 mol%, preferably 0.1 to 1 mol%, based on the whole bisphenol compound used in the step A.

8. The method of any of claims 1-7, wherein in step C the end-capping agent is one or more of phenol, methyl phenol, tert-butyl phenol, iso-octyl phenol, cumyl phenol, or chloroformates of the above phenolic compounds, and wherein the end-capping agent is used in an amount of 1 to 10 mole percent relative to the bisphenol compound used.

9. The method according to any one of claims 1 to 8, wherein in the step C, the pH of the reaction system is maintained at 10 to 13; and/or the reaction temperature is 5-60 ℃, preferably 10-40 ℃.

10. A process according to any one of claims 1 to 9, wherein the silicone copolycarbonate produced has a thickness of 3mm as measured according to ASTM D1003, a light transmission of 88% or more, a haze of 2% or less, and an izod notched impact strength of greater than 600J/m, preferably greater than 650J/m at-30 ℃ as measured according to ASTM D256.

Technical Field

The invention relates to a preparation method of siloxane copolycarbonate, and the prepared copolymer has good low-temperature impact resistance, excellent transparency and better process economy.

Background

Silicone copolycarbonates have received attention for their low temperature toughness, chemical resistance, flame retardancy, etc. over conventional bisphenol A polycarbonate. However, the introduction of siloxanes generally causes problems with poor transparency of the copolymers, manifested by reduced transmittance and increased haze, which can be improved by using siloxanes with lower degrees of polymerization or less, but which tend to result in a loss of low temperature impact properties, and various methods have been developed to improve this.

U.S. patent application No. 5530083 discloses a process for preparing polycarbonate oligomers containing chloroformate end groups prior to reaction with hydroxyl terminated siloxanes to obtain siloxane PC which avoids siloxane formation as a continuous long block structure and improves transparency, but is far from conventional PC.

U.S. patent application No. 6833422 discloses a multi-step process of converting a hydroxyl terminated siloxane to a bischloroformate siloxane by photochemical reaction, reacting with the prepared hydroxyl terminated polycarbonate oligomer to produce a siloxane PC intermediate, and further photochemical and polycondensation to produce a copolymer. The method has long reaction flow, needs multiple photochemical reactions, and has poor process economy and poor transparency.

Chinese patent CN 102471474B discloses a siloxane copolycarbonate having a polydiorganosiloxane phase domain average size of 5-40nm and a total light transmittance of 88% or more, but the copolymer suffers a large loss in low temperature impact resistance.

Chinese patent CN 103930466B discloses an improved polymerization process which requires high excess gas rate for the preparation of oligomers with acid chloride as the end group and batch preparation of bisphenol raw materials, and thus the process economy is not sufficient.

Disclosure of Invention

The present invention is directed to a method for preparing siloxane copolycarbonates. The siloxane copolycarbonate prepared by the invention can meet the requirement of a molded product with the thickness of 3mm, and the light transmittance can reach more than 88 percent and the haze can reach less than 2 percent based on the determination of ASTM D1003 standard. And also has excellent low temperature impact properties, and notched Izod Impact (IZOD) strength at-30 ℃ of greater than 600J/m, preferably greater than 650J/m, as measured according to ASTM D256. Compared with other methods which can achieve similar transparency, the method has the additional advantages of better process economy, only one phosgenation reaction process, one-time preparation of the bisphenol raw material and simpler and more convenient process.

In order to achieve the above purpose, the technical scheme of the invention is as follows:

a method of making a siloxane copolycarbonate, the method comprising the steps of:

step A: mixing an aqueous alkali metal hydroxide solution in which at least one bisphenol compound is dissolved, phosgene, an inert organic solvent to react, and separating a two-phase solution obtained by the reaction to obtain an organic phase containing a polycarbonate oligomer and an aqueous alkali metal hydroxide solution containing a bisphenol compound, respectively;

and a step B: mixing the organic phase obtained in the step A and siloxane shown in a formula (I) in the presence of a catalyst to react to obtain siloxane-polycarbonate intermediate solution;

wherein p is an average value of 1 to 100, R₁Is a single bond or C1-C6 alkylene, R₂Is C1-C6 alkyl or alkoxy;

and a step C: and (C) combining the siloxane-polycarbonate intermediate solution obtained in the step (B) with the alkali metal hydroxide aqueous solution containing the bisphenol compound obtained in the step (A), adding an end-capping reagent and the alkali metal hydroxide aqueous solution, optionally supplementing a catalyst, and mixing to complete the reaction to obtain the siloxane copolycarbonate.

In the step A of the present invention, the bisphenol compound is at least one or a combination of two or more of the compounds represented by the formula (II).

In the formula (II), R₃、R₄Each independently represents hydrogen, halogen, C1-C20 alkyl, C4-C20 cycloalkyl or C6-C20 aryl; m and n are independently integers of 0-4; w represents a single bond, an ether bond, a carbonyl group, a C1-C20 alkylene group, a C6-C20 arylene group, a C6-C20 alicyclic group, or the following groups:

wherein R is₅And R₆Each independently is hydrogen, C1-C20 alkyl, C4-C20 cycloalkyl or C6-C20 aryl; or R₅And R₆Together form a C4-C20 alicyclic ring, which may be optionally substituted with one or more C1-C20 alkyl, C6-C20 aryl, C7-C21 aralkyl, C4-C20 cycloalkyl groups, or a combination thereof.

Preferably, the bisphenol compound is selected from one or more combinations of 2, 2-bis (4-hydroxyphenyl) propane, 1-bis (4-hydroxyphenyl) -1-phenylethane, 4 '-dihydroxydiphenylmethane, 1-bis (3-methyl-4-hydroxyphenyl) cyclohexane, 1-bis (4-hydroxyphenyl) -3,3, 5-trimethylcyclohexane, 9-bis (4-hydroxyphenyl) fluorene, 9-bis (3-methyl-4-hydroxyphenyl) fluorene, 4' -dihydroxybiphenyl. More preferably, the bisphenol compound is 2, 2-bis (4-hydroxyphenyl) propane.

In the present invention, the alkali metal hydroxide may be sodium hydroxide, potassium hydroxide, etc., and sodium hydroxide is preferred. The concentration of the bisphenol compound in the aqueous alkali metal hydroxide solution is 5 to 30% by weight, preferably 12 to 25% by weight. The molar ratio of alkali metal hydroxide to bisphenol compound is 2.0-3.5: 1, preferably 2.01-2.5: 1.

the molar ratio of phosgene to bisphenol compound is such that the reaction ultimately yields a copolymer of high molecular weight, which ratio is 1-1.2: 1, preferably 1.01 to 1.15: 1.

the inert organic solvent may be C₁-C₆Chlorinated or brominated aliphatic hydrocarbons, C₄-C₆Chlorinated or brominated cycloaliphatic hydrocarbon, C₆-C₈Aromatic hydrocarbons, C₆-C₈A combination of one or more of chlorinated or brominated aromatic hydrocarbons. Preferably one or more of dichloromethane, dichloroethane, trichloroethane, tetrachloroethane, toluene, chlorobenzene, chloroform, more preferably dichloromethane. The weight ratio of the inert organic solvent to the aqueous alkali metal hydroxide solution in which at least one bisphenol compound is dissolved is 0.7 to 1.3: 1.

the two-phase solution obtained from the reaction was mixed and further separated into an organic phase and an aqueous phase. The separation mode can adopt a conventional standing layering equipment decanter, a plate type separator and equipment with better separation effect, such as a coalescer and a high-speed centrifuge.

The organic phase obtained by separation contains polycarbonate oligomers having a weight average molecular weight (determined by GPC after calibration beforehand with polystyrene or polycarbonate calibration substances) of between 1000-5000, preferably 1000-4000, from the viewpoint of efficiency of the subsequent polymerization and obtaining high transparency. The molar percentage of acid chloride in the end groups of the oligomer is 80% to 100%, preferably 90% or more, more preferably 95% or more. Using acyl chloride in proportion¹H-NMR method.

The content of the bisphenol compound in the aqueous solution obtained by separation is 7 to 50g/L, preferably 10 to 45g/L, and more preferably 15 to 40 g/L.

The molecular weight of the oligomer, the content of acid chloride in the terminal group and the content of bisphenol compound in the aqueous solution need to be controlled within the above-mentioned appropriate ranges, which would be disadvantageous for obtaining a copolymer having balanced low-temperature impact and transparency.

The reaction solution consisting of the organic phase and the aqueous phase can be obtained by adjusting the conditions of the residence time, the temperature, the mixing scale, the raw material ratio and the like of the reaction in the step A. Generally, aqueous solutions having higher acid chloride content oligomers and higher bisphenol compound content can be obtained by reducing reaction residence time, reducing reaction temperature, reducing mixing scale, and the like. The invention is not limited to the use of the above process conditions, and other known methods can be used to prepare the reaction solution meeting the requirements.

In the step B, the organic phase separated in the previous step is continuously mixed with siloxane in the presence of a catalyst for reaction to obtain a siloxane-polycarbonate intermediate. The reaction time is usually within 30min, preferably less than 20min, and more preferably less than 10min, from the viewpoint of reaction efficiency, although it takes several seconds to several tens of minutes depending on the temperature and the mixing intensity.

The siloxane structure is shown in (I) where p has an average value of 1 to 100, preferably 20 to 80, more preferably 30 to 60, for good low temperature impact properties and transparency. R₁Is a single bond (the single bond corresponds to "-" and represents a direct bond), a C1-C6 alkylene group, R₂Is C1-C6 alkyl or alkoxy.

The siloxane is used in an amount such that the siloxane segment portion is usually in the range of 1 to 30% by weight based on the weight of the finally prepared siloxane copolycarbonate, preferably 2 to 20% by weight, more preferably 3 to 10% by weight, in order to obtain low-temperature impact resistance and high transparency.

The siloxane is preferably added to the reaction system in solution in an inert organic solvent as described in procedure A, preferably dichloromethane. The concentration of siloxane in the solution is 10-30 wt%.

In the step B, a tertiary amine compound or a quaternary ammonium salt compound may be used as the catalyst, and triethylamine, tributylamine, trioctylamine, N-ethylpiperidine, N-methylpiperidine, N-isopropylpiperidine, N-N-propylpiperidine, tetrabutylammonium, tributylbenzylammonium, tetraethylammonium hydroxide, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium hydrogen sulfate, tetraethylammonium tetrafluoroborate and the like are included, but triethylamine is preferred. The amount of the catalyst to be used is 0.01 to 10 mol%, preferably 0.1 to 1 mol%, based on the whole bisphenol compound used in the step A.

In the step B, an aqueous alkali metal hydroxide solution may be optionally added to the reaction in order to neutralize the acid released during the reaction, thereby minimizing the conversion of the reaction solution into an acidic one and reducing the corrosion of the metal reactor. The alkali metal hydroxide may be sodium hydroxide, potassium hydroxide, etc., preferably sodium hydroxide, as described in the process A, and the concentration of the aqueous alkali metal hydroxide solution is 2 to 40% by weight. The number of moles of the alkali metal hydroxide added is not more than 5 times the number of moles of the siloxane added in the step B. The oil phase from step a usually contains saturated water, and a small amount of alkali is dissolved in the saturated water to perform a neutralizing action. If the oil phase contains water with a pH of > 7, optionally no additional aqueous alkali metal hydroxide solution is added.

In step C, the siloxane-polycarbonate intermediate solution obtained in step B is combined with the aqueous solution obtained in step A, and an end-capping reagent and an aqueous solution of an alkali metal hydroxide are added and mixed to complete the reaction, thereby obtaining the final copolycarbonate.

The end-capping agent may be an aromatic monophenol compound, or a chloroformate of the above phenol compound. Including but not limited to phenol, methyl phenol, tert-butyl phenol, isooctyl phenol, cumyl phenol or chloroformates of these phenolic compounds, with p-tert-butyl phenol being preferred. The amount of the end-capping agent is 1 to 10 mol% relative to the total bisphenol compound used. The blocking agent is preferably added dissolved in an inert organic solvent as described in procedure A, preferably dichloromethane.

The reaction needs to add an alkali metal hydroxide aqueous solution, the pH value of the reaction is kept at about 10-13, and the acyl chloride can not be completely reacted if the pH value is too low. The amount of aqueous alkali metal hydroxide solution added depends on the excess phosgene, said alkali metal hydroxide being as described in process B, preferably sodium hydroxide, the concentration of aqueous alkali metal hydroxide solution being 2-40% by weight.

Optionally, a catalyst may be added additionally to accelerate the reaction, the type and amount of the catalyst are the same as those described in the process step B, the amount of the added catalyst is not more than that added in the process step B, and preferably, the whole catalyst is added in the process step B.

The reaction time is influenced by the mixing intensity and the amount of the catalyst added, and is generally suitably controlled within 60min from the viewpoint of the reaction efficiency.

In order to improve the yield and economy of the bisphenol compound, the content of the bisphenol compound remaining in the aqueous phase after the reaction in step C is less than 5g/L, preferably less than 3 g/L. The residual content of bisphenol can be reduced by increasing the excess ratio of phosgene to bisphenol compound, increasing the reaction temperature, increasing the reaction mixing strength, and the like.

The mixing reaction of the above procedures can adopt a kettle type, a tubular type or a circulating reactor. The kettle type reactor can be internally provided with stirring blades as a power source for liquid mixing or liquid and solid mixing, and the internal blades can adopt a single layer, a double layer or more layers so as to achieve the dimension required by reaction mixing. The paddle is preferably axial flow paddle, and can also be combined with axial flow paddle and radial paddle or radial paddle. The number of the reaction kettles can be one, and a plurality of the kettles can be connected in series.

The tubular reactor is used, and in order to meet the mixing requirement, a stable static mixer without moving parts or a special dynamic mixer with high mixing intensity can be adopted. The static mixer may be a commercial mixing unit, and the dynamic mixer may be a continuous emulsifying machine, a homogenizer, or the like. The whole reaction can be carried out in a plurality of tubular reactors connected in series, and the tubular reactors can be empty tubes or mixing units designed at intervals according to the requirement of the reaction mixing scale.

The circulating reactor is generally obtained by combining units such as a circulating pump, a buffer kettle, a heat exchanger, a mixer and the like, the combination mode can be selected at will, and common combination modes are well known to researchers in the field. The mixer may use static or dynamic equipment, substantially in accordance with the type of mixer used in the tubular reactor.

The above reactor types may be used alone or in combination to increase the efficiency of the reaction. The temperature of the reaction process of the above procedures is 5-60 ℃, preferably 10-40 ℃.

The organic phase solution obtained after completion of the polymerization can be washed by a known conventional method to remove the residual phenolic compound and the catalyst. The organic phase after washing and purification can be further subjected to removal of the organic solvent by known methods of solvent removal, for example, steam flocculation, spray drying, precipitation with a poor solvent, etc., and dried to obtain the siloxane copolycarbonate of the present invention.

The siloxane copolycarbonates prepared according to the present invention have good transparency. The light transmittance of the molded product with the thickness of 3mm can reach more than 88 percent and the haze can reach less than 2 percent based on the ASTM D1003 standard. And also has excellent low temperature impact properties, and notched Izod Impact (IZOD) strength at-30 ℃ of greater than 600J/m, preferably greater than 650J/m, as measured according to ASTM D256.

Detailed Description

The following examples are intended to illustrate the invention, which is not limited to the scope of the examples, but also includes any other modifications within the scope of the claims of the invention.