阅读说明：本技术 芳香族聚碳酸酯寡聚体固体物 (Aromatic polycarbonate oligomer solid ) 是由 尾崎充孝 桥本美和 须藤健 于 2018-05-17 设计创作，主要内容包括：本发明的课题在于提供低分子量成分得到显著减少,无含氯化合物或其得到显著减少,疏松堆密度(Losse bulk density)大从而容易处理的芳香族聚碳酸酯寡聚体固体物。由含有下述式(1)所示的重复单元,重均分子量为500～10000,在由高效液相色谱法进行的测定中低分子量成分为5.0面积％以下,疏松堆密度为0.30g/cm<Sup>3</Sup>以上的芳香族聚碳酸酯寡聚体固体物可以解决上述课题。<Image he="165" wi="700" file="DDA0002267905470000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>(The present invention addresses the problem of providing an aromatic polycarbonate oligomer solid which is significantly reduced in low-molecular-weight components, contains no chlorine-containing compounds or is significantly reduced in chlorine-containing compounds, and has a large bulk density (Losse bulk density) and is therefore easy to handle. Contains a repeating unit represented by the following formula (1), has a weight average molecular weight of 500-10000, and has a low molecular weight component of 5.0 area% or less and a loose bulk density of 0.30g/cm in a measurement by high performance liquid chromatography 3 The above aromatic polycarbonate oligomer solid can solve the above problems.)

1. An aromatic polycarbonate oligomer solid substance characterized by containing a repeating unit represented by the following formula (1), having a weight average molecular weight of 500 to 10000, a low molecular weight component of 5.0 area% or less in measurement by high performance liquid chromatography, and a loose bulk density of 0.30g/cm³In the above-mentioned manner,

formula (1)

2. An aromatic polycarbonate oligomer solid product which is obtained from an aromatic dihydroxy compound represented by the following formula (2) and a carbonic acid diester, has a weight average molecular weight of 500 to 10000, contains a low molecular weight component of 5.0 area% or less in measurement by high performance liquid chromatography, and has a loose bulk density of 0.30g/cm³In the above-mentioned manner,

formula (2)

Technical Field

The present invention relates to an aromatic polycarbonate oligomer solid matter, and more particularly to an aromatic polycarbonate oligomer solid matter which is produced from 1, 1-bis (4-hydroxyphenyl) -1-phenylethane and a carbonate precursor.

Background

Polycarbonate oligomers are widely used as intermediate raw materials in the production of high molecular weight polycarbonates by the interfacial polymerization method, raw materials in the production of high molecular weight polycarbonates by the melt polymerization method or the solid phase polymerization method, and polymer modifiers such as surface modifiers, flame retardants, ultraviolet absorbers, fluidity modifiers, plasticizers, and compatibilizers for resin alloys. In recent years, the performance of demands for polycarbonate oligomers has been increasingly diversified and severer, and further improvements have been sought for polycarbonate oligomers other than bisphenol a type polycarbonate oligomers. Among them, further improvement of performance is also sought for an aromatic polycarbonate oligomer using 1, 1-bis (4-hydroxyphenyl) -1-phenylethane and a carbonate precursor as raw materials.

On the other hand, the interfacial polymerization method, which produces a polycarbonate oligomer as an intermediate raw material for a high molecular weight polycarbonate by reacting an aromatic dihydroxy compound with Phosgene (Phosgene) as a raw material in a methylene chloride solvent, is the mainstream of the method for producing a polycarbonate oligomer, and the following methods are generally employed: phosgene is blown into an alkaline aqueous solution of a bisphenol to produce a polycarbonate oligomer having a reactive chloroformate group, and the polycarbonate oligomer is further mixed with an alkaline aqueous solution of a bisphenol to carry out a polycondensation reaction in the presence of a polymerization catalyst such as a tertiary amine. However, the interfacial polymerization method has the following problems: it is necessary to use toxic phosgene, by-produced hydrogen chloride and sodium chloride, and chlorine-containing compounds such as methylene chloride used in large amounts as a solvent, which cause corrosion of the apparatus and make it difficult to separate impurities such as sodium chloride and residual methylene chloride, which adversely affect the physical properties of the polymer. Accordingly, a method for producing a polycarbonate oligomer by a melt transesterification method using an aromatic dihydroxy compound and a carbonic acid diester as raw materials has also been put into practical use. However, the melt transesterification method can solve the above-mentioned problems in the interfacial polymerization method, but still has a problem that the resulting oligomer contains a large amount of residual monomers or low-molecular-weight components.

On the other hand, among polycarbonate oligomers obtained by the interfacial polymerization method, polycarbonate oligomers containing, as monomer components, bisphenol compounds other than bisphenol a (hereinafter, sometimes referred to as special bisphenols), 2-bis (4-hydroxy-3-methylphenyl) propane (patent document 1), 1-bis (4-hydroxyphenyl) cyclohexanes (patent document 2), and 9, 9-bis (4-hydroxyphenyl) fluorene (patent document 3), respectively, are known.

However, since these specific bisphenol polycarbonate oligomers are produced by the interfacial polymerization method, when they are used as a prepolymer or an additive, there is a concern that the residual chlorine-containing compound causes corrosion of the apparatus and deterioration of the physical properties of the polymer as described above.

Further, as aromatic polycarbonate oligomers obtained by a melt transesterification method, there are known specific bisphenol polycarbonate oligomers such as bisphenol a polycarbonate oligomer and 1, 1-bis (4-hydroxyphenyl) cyclohexane (patent documents 4 and 5).

However, these polycarbonate oligomers are removed directly after the reaction or are subjected to only a heat treatment without being subjected to a purification step, and therefore low-molecular-weight components generated in the reaction remain. Therefore, when these are used as a polycarbonate raw material for melt polymerization or solid phase polymerization, the possibility of causing troubles such as clogging of a line due to volatilization of low molecular weight components in the apparatus is increased. Further, when a high molecular weight polycarbonate is formed, there is a possibility that the impact strength is lowered or the polycarbonate adheres to a mold. Further, if a large amount of low molecular weight components in the polycarbonate oligomer remains, the storage stability may be poor, and the quality such as coloring may be lowered.

Heretofore, there has been known no method of taking out an aromatic polycarbonate oligomer, which is obtained from 1, 1-bis (4-hydroxyphenyl) -1-phenylethane and a carbonate precursor as raw materials, as a solid from a reaction product, but as a method of taking out an aromatic polycarbonate oligomer, which is obtained from 2, 2-bis (4-hydroxyphenyl) propane and a carbonate precursor as raw materials, as a solid from a reaction product, the following methods have been known: a methylene chloride solution of 2, 2-bis (4-hydroxyphenyl) propane polycarbonate oligomer obtained by the interfacial polymerization method was dropped into methanol to precipitate it. (patent document 1).

However, since the polycarbonate oligomer obtained by the above method is produced by an interfacial polymerization method and then precipitated using a methylene chloride solution, chlorine-containing compounds such as methylene chloride remaining in the polycarbonate oligomer cannot be completely removed, and there is a concern that the apparatus may be corroded, the physical properties of the polymer may be deteriorated, and the like as described above. Further, since polycarbonate oligomers of 2, 2-bis (4-hydroxyphenyl) propane obtained from a solvent system using the above tetrahydrofuran or dichloromethane solution have a low bulk density, they are difficult to handle, and when used as a reaction raw material, not only a large amount of energy is required for charging a reaction vessel, but also the reaction vessel itself needs to be made larger.

Further, as a method for taking out a polycarbonate reaction product having a high molecular weight as a solid, the following methods are known: a methylene chloride solution of a polycarbonate having a high molecular weight, which is obtained by polymerizing 1, 1-bis (4-hydroxyphenyl) -1-phenylethane and a carbonate precursor as raw materials by an interfacial polymerization method, is dropped into warm water, and the solvent is evaporated to remove the solvent, thereby taking out the polymer as a solid (patent document 6).

However, since the above oligomers are produced by the interfacial polymerization method and then precipitated using a methylene chloride solution, chlorine-containing compounds such as methylene chloride remaining in the polycarbonate cannot be completely removed, and there is a concern that the residual chlorine-containing compounds may cause corrosion of the apparatus and deterioration of the polymer properties.

Further, since only the solvent in the polymerization reaction liquid is removed and otherwise the polymerization reaction liquid is directly solidified without purification effect, low molecular weight components generated in the reaction remain, and as described above, there is a concern that the storage stability is poor and the quality such as coloring is lowered.

Disclosure of Invention

The present invention was made in view of the above circumstances of polycarbonate oligomers, and an object thereof is to provide a solid substance such as a powder which has a molecular weight suitable for improving reactivity without increasing viscosity, is remarkably reduced in low molecular weight components, contains no chlorine-containing compounds or is remarkably reduced in low molecular weight components, and has a large bulk density (los bulk density) and is easily handled, in an aromatic polycarbonate oligomer using 1, 1-bis (4-hydroxyphenyl) -1-phenylethane and a carbonate precursor as raw materials.

The present inventors have conducted intensive studies in order to solve the above problems, and as a result, have found that in an aromatic polycarbonate oligomer using 1, 1-bis (4-hydroxyphenyl) -1-phenylethane and a carbonate precursor as raw materials, a solid such as a powder which is remarkably reduced in low molecular weight components, contains no chlorine-containing compounds or is remarkably reduced in the content thereof, and has a high bulk density and is easily handled can be obtained by precipitating or treating an oligomer of a reaction product with a specific soluble solvent or a specific precipitating solvent and drying the oligomer, thereby completing the present invention.

The present invention is as follows.

1. An aromatic polycarbonate oligomer solid substance characterized by containing a repeating unit represented by the following formula (1), having a weight average molecular weight of 500 to 10000, a low molecular weight component of 5.0 area% or less in measurement by high performance liquid chromatography, and a loose bulk density of 0.30g/cm³In the above-mentioned manner,

formula (1)

2. An aromatic polycarbonate oligomer solid product which is obtained from an aromatic dihydroxy compound represented by the following formula (2) and a carbonic acid diester, has a weight average molecular weight of 500 to 10000, contains a low molecular weight component of 5.0 area% or less in measurement by high performance liquid chromatography, and has a loose bulk density of 0.30g/cm³In the above-mentioned manner,

formula (2)

Since the aromatic polycarbonate oligomer solid of the present invention has a weight average molecular weight of 500 to 10000, the viscosity is not increased and the reactivity is improved. Further, since the content of the low-molecular-weight component in the measurement by high performance liquid chromatography is 5.0 area% or less, the quality such as coloring due to oxidation or the like is not deteriorated, and the storage stability is excellent.

Further, when a polycarbonate is produced by a melt polymerization method or a solid phase polymerization method using the polycarbonate oligomer solid of the present invention, since the amount of low molecular weight component is extremely small, the volatile component in the apparatus is reduced, and troubles such as clogging of a line can be prevented, and it is also expected that the purification step for removing the low molecular weight component from the obtained polycarbonate resin is not required or can be simplified.

Further, since the loose bulk density of the solid matter was 0.30g/cm³This makes handling easy, and requires a smaller reaction vessel capacity when used as a reaction raw material, thereby improving productivity.

Detailed Description

The aromatic polycarbonate oligomer solid of the present invention will be described in detail below.

The aromatic polycarbonate oligomer solid of the present invention is the following aromatic polycarbonate oligomer solid: containing a repeating unit represented by the following formula (1)The weight average molecular weight is 500 to 10000, the low molecular weight component is less than 5.0 area% in the determination by high performance liquid chromatography, and the loose bulk density is 0.30g/cm³The above.

Formula (1)

The method for producing the aromatic polycarbonate oligomer according to the present invention is not particularly limited, and any conventionally known method can be used. Specific examples thereof include an interfacial polymerization method, a melt transesterification method, a solid-phase polymerization method, a ring-opening polymerization method of a cyclic carbonate compound, a pyridine method, etc., and among them, an interfacial polymerization method and a melt transesterification method in which an aromatic dihydroxy compound and a carbonate precursor are used as raw materials are preferable.

The raw material for producing the aromatic polycarbonate oligomer according to the present invention is 1, 1-bis (4-hydroxyphenyl) -1-phenylethane represented by the following formula (2).

Formula (2)

The aromatic dihydroxy compound used as a raw material of the aromatic polycarbonate oligomer according to the present invention may be a dihydroxy compound other than 1, 1-bis (4-hydroxyphenyl) -1-phenylethane represented by the above formula (2), for example, bisphenol a, as a copolymerization raw material, within a range not to impair the effects of the present invention.

When the copolymerization raw material is used, the proportion of the copolymerization raw material of the dihydroxy compound other than 1, 1-bis (4-hydroxyphenyl) -1-phenylethane represented by the above formula (2) to be mainly used is in the range of 0 to 30 mol%, preferably in the range of 0 to 20 mol%, more preferably in the range of 0 to 10 mol%, further preferably in the range of 0 to 5 mol%, and particularly preferably in the range of 0 to 2 mol% of the total dihydroxy compounds.

As the carbonate precursor to be reacted with the aromatic dihydroxy compound, a Carbonyl halide (Carbonyl halide), a carbonate, a haloformate, or the like can be used. Specific examples thereof include phosgene; carbonic acid diesters such as diaryl carbonates such as diphenyl carbonate and ditolyl carbonate, and dialkyl carbonates such as dimethyl carbonate and diethyl carbonate; dihaloformates of dihydric phenols, and the like. These carbonate precursors may be used alone or in combination of 2 or more.

These carbonate precursors are usually appropriately selected depending on the production method, and phosgene is preferred in the interfacial polymerization method and a carbonic acid diester, particularly diphenyl carbonate, is preferred in the melt transesterification method in obtaining the aromatic polycarbonate oligomer according to the present invention.

The aromatic polycarbonate oligomer according to the present invention has a weight average molecular weight of 500 to 10000, preferably 1000 to 9000, more preferably 1500 to 8500, and further preferably 2000 to 8000. By setting such a molecular weight, viscosity does not rise and reactivity also rises.

The low-molecular-weight component according to the present invention is a component mainly composed of an ester exchange condensate having a polymerization degree of 2 or less, and other components including a low-molecular-weight compound such as a raw material monomer residue, a distillation residue of phenol as a reaction product, and a solvent at the time of reaction and purification, as measured by high performance liquid chromatography (area% by high performance liquid chromatography). The transesterification condensate is specifically a compound having an absolute molecular weight of 2 molecules of an aromatic dihydroxy compound and 3 molecules of a carbonate precursor, which are condensed, the molecular weight of the compound being different depending on the aromatic dihydroxy compound or the carbonate precursor as the raw material of the formula (1), and when the aromatic dihydroxy compound is 1, 1-bis (4-hydroxyphenyl) -1-phenylethane represented by the formula (2), the carbonate precursor is diphenyl carbonate, and 1 species of homopolymerization is performed, the compound having an absolute molecular weight of 846 or less is a dimer having phenyl groups at both ends.

Assuming that such low molecular weight components are exemplified by chemical formulas, when the aromatic dihydroxy compound is 1, 1-bis (4-hydroxyphenyl) -1-phenylethane and the carbonate precursor is diphenyl carbonate, the following compounds can be exemplified.

The measurement conditions of the low molecular weight component according to the present invention based on high performance liquid chromatography are conditions under which the low molecular weight component is separated from a compound having an absolute molecular weight equal to or higher than the low molecular weight component, and when the polycarbonate oligomer of the present invention is identified, the area% of the low molecular weight component is measured using an absorptiometer at 254 nm.

The content of the low-molecular weight component contained in the aromatic polycarbonate oligomer according to the present invention is 5.0 area% or less, preferably 4.0 area% or less, more preferably 3.0 area% or less, still more preferably 2.0 area% or less, and particularly preferably 1.0 area% or less, as measured by high performance liquid chromatography under the above-mentioned conditions.

In view of the yield, the content of the low-molecular weight component contained in the aromatic polycarbonate oligomer according to the present invention is preferably 0.01 area% or more, more preferably 0.05 area% or more, and still more preferably 0.1 area% or more, in the measurement by high performance liquid chromatography under the above-described conditions.

Furthermore, the loose bulk density of the aromatic polycarbonate oligomer solid of the invention is 0.30g/cm³Above, preferably 0.31g/cm³Above, more preferably 0.32g/cm³The above, and preferably 0.90g/cm³Hereinafter, more preferably 0.80g/cm³Hereinafter, more preferably 0.70g/cm³Hereinafter, it is particularly preferably 0.65g/cm³The following.

In the method for producing an aromatic polycarbonate oligomer according to the present invention, a method of obtaining an aromatic polycarbonate oligomer by a melt transesterification method will be described. In the melt transesterification method, a conventionally known method using an aromatic dihydroxy compound and a carbonic acid diester as raw materials can be used.

For example, when the aromatic dihydroxy compound as the raw material is 1, 1-bis (4-hydroxyphenyl) -1-phenylethane and the carbonic acid diester as the raw material is diphenyl carbonate, the reaction to obtain an aromatic polycarbonate oligomer is shown by the following reaction formula.

The melt transesterification is carried out in such a manner that the aromatic dihydroxy compound and the carbonic acid diester are stirred while being heated in the presence of a catalyst under an inert gas atmosphere at normal pressure or reduced pressure, and the produced phenol is distilled off.

Specific examples of the carbonic acid diester to be reacted with the aromatic dihydroxy compound include diaryl carbonates such as diphenyl carbonate, ditolyl carbonate and bis (m-cresol) carbonate, dialkyl carbonates such as dimethyl carbonate, diethyl carbonate and dicyclohexyl carbonate, alkyl aryl carbonates such as methyl phenyl carbonate, ethyl phenyl carbonate and cyclohexyl phenyl carbonate, and diene carbonates such as divinyl carbonate, diisopropenyl carbonate and diallyl carbonate. Diaryl carbonates are preferred, diphenyl carbonate being particularly preferred.

In general, the mixing ratio of the carbonic acid diester and the aromatic dihydroxy compound or the degree of reduced pressure during the ester interchange reaction can be adjusted to obtain an aromatic polycarbonate oligomer having a desired molecular weight and an adjusted amount of terminal hydroxyl groups.

The mixing ratio of the carbonic acid diester and the aromatic dihydroxy compound to obtain the aromatic polycarbonate oligomer according to the present invention is usually 0.5 to 1.5 times by mole, preferably 0.6 to 1.2 times by mole, based on 1 mole of the aromatic dihydroxy compound.

When the melt transesterification is carried out, a transesterification catalyst may be used as necessary in order to increase the reaction rate.

The transesterification catalyst is not particularly limited, and examples thereof include alkali metal compounds such as inorganic alkali metal compounds such as hydroxides, carbonates, and hydrogen carbonate compounds of lithium, sodium, and cesium, and organic alkali metal compounds such as alkoxides and organic carboxylates; alkaline earth metal compounds such as hydroxides of beryllium, magnesium and the like, inorganic alkaline earth metal compounds such as carbonates and the like, organic alkaline earth metal compounds such as alkoxides, organic carboxylates and the like; basic boron compounds such as sodium salts, calcium salts, and magnesium salts of tetramethylboron, tetraethylboron, and butyltriphenylboron; basic phosphorus compounds such as 3-valent phosphorus compounds including triethylphosphine and tri-n-propylphosphine, and quaternary phosphonium salts derived from these compounds; and basic ammonium compounds such as tetramethylammonium hydroxide, tetraethylammonium hydroxide and tetrabutylammonium hydroxide, and amine compounds such as 4-aminopyridine, 2-dimethylaminoimidazole and aminoquinoline. Among them, alkali metal compounds are preferable, and cesium compounds such as cesium carbonate and cesium hydroxide are particularly preferable.

The amount of the catalyst to be used may be within a range in which the catalyst residue does not cause a problem in quality of the oligomer to be produced, and an appropriate amount of the catalyst to be used varies depending on the kind of the catalyst, and therefore, for example, is usually 0.05 to 100. mu. mol, preferably 0.08 to 50. mu. mol, more preferably 0.1 to 20. mu. mol, and further preferably 0.1 to 5. mu. mol based on 1 mole of the aromatic dihydroxy compound.

The catalyst may be added as it is or dissolved in a solvent, and the solvent is preferably water, phenol or the like which does not affect the reaction.

The reaction conditions for the melt transesterification reaction are usually in the range of 120 to 360 ℃, preferably in the range of 150 to 280 ℃, and more preferably in the range of 180 to 260 ℃. If the reaction temperature is too low, the transesterification reaction cannot proceed, and if the reaction temperature is high, side reactions such as decomposition reaction may occur, which is not preferable. The reaction is preferably carried out under reduced pressure. The reaction pressure is preferably a pressure at which the raw material carbonic acid diester is not distilled out of the system and the by-produced phenol is distilled out at the reaction temperature. Under such reaction conditions, the reaction is usually completed within about 0.5 to 10 hours.

Next, a separation step is performed using the reaction product obtained in the reaction step.

The reaction product containing the aromatic polycarbonate oligomer obtained in the above reaction step is usually a transparent viscous substance in a molten state at around the reaction temperature, and is a solid at around room temperature. By treating the reaction product having such properties with a specific solvent and drying the treated product, the low molecular weight component of the present invention can be significantly reduced, and a solid of the present invention such as a powder having a high bulk density and easy handling can be obtained.

The method for the separation step from the reaction product is not particularly limited, and for example, the following methods are preferable: the whole reaction product containing the low molecular weight components is dissolved in a solvent (good solvent) which can be dissolved well to prepare a solution, and then the solution is mixed with a solvent (poor solvent) which has extremely low solubility but can selectively dissolve the low molecular weight components to dissolve and separate the low molecular weight components and obtain oligomers as precipitates, or the reaction product is directly mixed in a poor solvent to form a slurry, and the low molecular weight components are dissolved and separated in the poor solvent to obtain oligomers as precipitates, and the resulting mixture is filtered and dried to obtain the aromatic polycarbonate oligomer solid having a high apparent bulk density. Further, the above separation step may be repeated a plurality of times using the obtained aromatic polycarbonate oligomer as required.

The good solvent is a solvent capable of dissolving the polycarbonate oligomer and the low molecular weight component simultaneously and well, and specific examples thereof include aromatic hydrocarbon solvents such as toluene and xylene, and aliphatic ketone solvents having 1 to 8 carbon atoms such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. Halogen-containing solvents such as methylene chloride and tetrahydrofuran are not suitable as good solvents because chlorine-containing residues are mixed into the obtained solid or the bulk density of the solid is reduced.

The poor solvent is a solvent which is extremely low in solubility of the polycarbonate oligomer and can dissolve low-molecular-weight components and can obtain a solid having a high bulk density from which a dried solid of the polycarbonate oligomer is separated, and specifically includes an aliphatic alcohol solvent having 1 to 6 carbon atoms such as methanol, ethanol, or propanol, or a mixture of the aliphatic alcohol solvent and water.

When the solvent used as the good solvent is a water-soluble ketone solvent such as acetone, water alone may be used as the poor solvent.

In the above separation step, the method of dissolving the whole reaction product in the good solvent to prepare a solution, mixing the solution with the poor solvent to dissolve and separate the low molecular weight component and obtain the oligomer as the precipitate is further described in detail, for example, the whole reaction product is dissolved in the good solvent by heating as necessary using a heating apparatus, a stirrer, a container with a condenser, and the solution is dropped into the poor solvent, or conversely the poor solvent is dropped into the solution to precipitate the aromatic polycarbonate oligomer and filter it.

Here, the ratio of the amounts of the good solvent and the poor solvent to the reaction product is not particularly limited, and when the amount of the good solvent is too large, the yield is lowered, and when the amount of the poor solvent is too large, the solvent recovery cost is increased, which is not preferable.

Therefore, the good solvent is preferably used in a range of 0.5 to 20 times by weight and the poor solvent is preferably used in a range of 0.5 to 50 times by weight, more preferably 0.6 to 15 times by weight, and the poor solvent is preferably used in a range of 0.6 to 30 times by weight, particularly preferably 0.7 to 12 times by weight, and the poor solvent is preferably used in a range of 1.0 to 25 times by weight, based on the reaction product.

The amount of the poor solvent is preferably 1.0 to 20 times, more preferably 2.0 to 10 times, and particularly preferably 3.0 to 8.0 times the weight of the good solvent.

Further, as a method for obtaining an oligomer as a precipitate by mixing the reaction product in a slurry form directly in a lean solvent, dissolving and separating a low-molecular weight component in the lean solvent, the reaction product can be used as it is when the reaction product as a whole is a viscous product in a molten state, or can be suitably pulverized as needed when it is a solid, and for example, a heating apparatus, a stirrer, and a vessel with a condenser are used, and the reaction product is heated as needed, added to the lean solvent while stirring to be in a slurry form, and the low-molecular weight component is dissolved and separated in the lean solvent, and the aromatic polycarbonate oligomer is precipitated and filtered out. Here, the ratio of the amount of the lean solvent to the reaction product is not particularly limited, and if the amount of the lean solvent is too large, the solvent recovery cost is undesirably increased.

Therefore, the lean solvent is preferably used in a range of 1 to 50 times by weight, more preferably 1 to 30 times by weight, and particularly preferably 2 to 20 times by weight with respect to the reaction product.

The temperature and time for the dissolution separation and precipitation in the separation step are not particularly limited, and may vary depending on the kind of the solvent or the reaction product used, and are generally within a range of 1 to 40 hours at 0 to 100 ℃.

The solution in which the low molecular weight components are dissolved can be separated from the precipitate using, for example, a filter or the like to remove only the solution, and the residue is dried using a dryer such as a vacuum dryer or a hot air dryer, whereby the aromatic polycarbonate oligomer having a reduced low molecular weight component and a high bulk density of the present invention can be obtained.

Next, a method for obtaining the aromatic polycarbonate oligomer according to the present invention by the interfacial polymerization method will be described. In the interfacial polymerization method, a conventionally known method of reacting an aromatic dihydroxy compound with a carbonate precursor such as phosgene in an inert solvent can be used.

In the polymerization reaction, for example, in the presence of an organic solvent inert to the reaction and an aqueous alkaline solution, 1-bis (4-hydroxyphenyl) -1-phenylethane represented by the above formula (2) is reacted with phosgene while usually maintaining the pH at 9 or more and using a molecular weight modifier (end terminator) as necessary, and then a polymerization catalyst such as tertiary amine or quaternary ammonium salt is added to conduct interfacial polymerization, thereby obtaining a polycarbonate oligomer.

The addition of the molecular weight modifier is not particularly limited as long as it is a period from the time of phosgenation to the time of polymerization reaction initiation. The reaction temperature is usually 0 to 40 ℃, and the reaction is finished for about 10 minutes to 6 hours under the reaction conditions.

Specific examples of the organic solvent inert to the reaction include chlorinated hydrocarbons such as dichloromethane, 1, 2-dichloroethane, chloroform, monochlorobenzene and dichlorobenzene, and aromatic hydrocarbons such as benzene and toluene. Examples of the basic compound for trapping hydrogen chloride generated by the reaction include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide.

Examples of the molecular weight modifier include compounds having a monovalent phenolic hydroxyl group, and specific examples thereof include phenol, m-methylphenol, p-methylphenol, m-propylphenol, p-t-butylphenol, and long-chain alkyl-substituted phenols. The amount of the molecular weight modifier used is preferably 50 to 0.5 mol, particularly preferably 30 to 1 mol, based on 100 mol of the aromatic dihydroxy compound.

Examples of the polymerization catalyst include tertiary amines such as trimethylamine, triethylamine, tributylamine, tripropylamine, trihexylamine, and pyridine; quaternary ammonium salts such as trimethylbenzylammonium chloride, tetramethylammonium chloride, triethylbenzylammonium chloride and the like.

In the interfacial polymerization method, the reaction product containing the polycarbonate oligomer is usually obtained as a solution of chlorine compounds such as methylene chloride and aromatic hydrocarbon organic solvents such as benzene. Therefore, in order to obtain a polycarbonate oligomer solid, it is necessary to separate and dry the polycarbonate oligomer from the solution, and as separation methods, "gel concentration method" (gelation by solvent distillation, gelation by flash concentration, etc.), "warm water dropping method", "precipitation method", and the like are known. However, the polycarbonate oligomers obtained by separation and drying as described above have many impurities such as chlorine content residue, low molecular weight content residue, residue resulting from high-temperature heating in a dryer, and the like, and are solid matters such as powdery matters having a low bulk density, therefore, in the separation step of the present invention, the polycarbonate oligomer solid obtained from the reaction product is dissolved in a specific solvent (good solvent), followed by a separation step of subjecting the resulting mixture to a precipitation treatment with a specific precipitating solvent (lean solvent) or a slurry treatment in a lean solvent of a polycarbonate oligomer solid obtained from the reaction product and drying the resulting mixture, thus, a solid material of the present invention such as a powder having a remarkably reduced low molecular weight component, containing no or remarkably reduced chlorine-containing compounds, and having a high bulk density and thus being easy to handle can be obtained.

The method for the separation step of obtaining the solid matter of the present invention from the polycarbonate oligomer solid matter obtained from the reaction product is not particularly limited, and the preferred method is the same as the method for the separation step of obtaining the solid matter of the present invention from the reaction product in the above-mentioned melt transesterification method, and the preferred good solvent, poor solvent, separation conditions and the like are the same.

The use of the compound of the present invention obtained as described above is explained.

The polycarbonate oligomer of the present invention can be used as a raw material in the production of a high molecular weight polycarbonate by various polymerization methods, and among these, an aromatic polycarbonate obtained by a melt polymerization method or a solid phase polymerization method using the compound of the present invention as a raw material is excellent in transparency, heat resistance, mechanical properties, impact resistance, fluidity and the like, and is expected to be applied to optical applications such as optical disks and lenses, or engineering plastics in various fields such as the automobile field, the electric and electronic fields, and various containers.

Further, the compound of the present invention can be widely used as additives such as surface modifiers, flame retardants, ultraviolet absorbers, fluidity modifiers, plasticizers, polymer modifiers such as compatibilizers for resin alloys, and the like.

The compound of the present invention can be used as a raw material for various resins other than polycarbonate. In this case, the compound of the present invention can be used as it is or processed for use.