JP2009191194A - Method for producing polycarbonate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polycarbonate which has low melt viscosity, low birefringence and a high refractive index and into which a functionalized functional group can be introduced. <P>SOLUTION: In the method for producing the polycarbonate, the polycarbonate is obtained by condensing di-t-butyl tricarbonate and a polyhydric phenol. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a method for producing polycarbonate, and more particularly to a method for producing polycarbonate that can be suitably used as an optical material or a resist resin.

  Polycarbonate is an amorphous plastic with excellent characteristics such as impact resistance, transparency, dimensional stability, flame retardancy, high heat resistance, and weather resistance. As an engineering plastic that replaces metal and glass, Widely used in the fields of cameras, mobile phones, OA equipment, electronic equipment, precision machinery, medical equipment, etc. (see, for example, Patent Document 1).

  Since polycarbonate has a higher refractive index than other thermoplastic resins, it has recently been applied as a new application in the optical field such as an optical disk substrate and an optical lens. However, when polycarbonate is used as an optical material, there is a problem that the melt viscosity is high and sufficient fluidity required in the molding process cannot be obtained. Therefore, for example, by reducing the shear rate dependence of the logarithmic value of the melt viscosity with respect to the viscosity average molecular weight of the polycarbonate resin, introducing a predetermined substituent at the molecular end, and making the molecular weight distribution extremely narrow, etc. The fluidity is improved (for example, see Patent Document 2).

JP 2001-159821 A JP 2007-308687 A

  However, for example, when a polycarbonate is used as the resist resin, the polycarbonate needs to have a functional functional group in the molecule. Therefore, the polycarbonate has to be prepared using a monomer having a functional functional group in advance, and there is a limit to the functional functional group that can be used.

  Further, when polycarbonate is used as an optical material, particularly as a material for an optical lens, there is a problem that large birefringence is generated from the viewpoint of lens resolution. The large birefringence of polycarbonate is due to the large optical anisotropy of the aromatic group that constitutes the main chain of the polycarbonate, etc., and optical birefringence due to molecular orientation during injection molding and applied birefringence due to residual stress Distortion will occur.

  The present invention has been made in view of such problems of the prior art, and the problem is that the melt viscosity and birefringence index are low, the refractive index is high, and a functional functional group is introduced. Another object of the present invention is to provide a method for producing polycarbonate.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be achieved by condensing di-t-butyl tricarbonate and polyhydric phenol, and the present invention. It came to complete.

  That is, according to this invention, the manufacturing method of the polycarbonate shown below is provided.

  [1] A method for producing a polycarbonate by condensing di-t-butyl tricarbonate and a polyhydric phenol to obtain a polycarbonate.

  [2] The method for producing a polycarbonate according to [1], wherein the polyhydric phenol is a compound represented by the following general formula (1).

（前記一般式（１）中、Ｒ^１は、炭素数１〜６のアルキル基を示す。）

(In the general formula (1), R ¹ represents an alkyl group having 1 to 6 carbon atoms.)

  [3] The method for producing a polycarbonate according to [1], wherein the polyhydric phenol is a compound represented by the following general formula (2).

（前記一般式（２）中、Ｒ^２は、炭素数１〜６のアルキル基を示す。）

(In the general formula (2), R ² represents an alkyl group having 1 to 6 carbon atoms.)

  The method for producing a polycarbonate of the present invention has an effect that a polycarbonate having a low melt viscosity and a low birefringence, a high refractive index, and a functional functional group can be produced.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below, but the present invention is not limited to the following embodiment, and is based on the ordinary knowledge of those skilled in the art without departing from the gist of the present invention. It should be understood that modifications and improvements as appropriate to the following embodiments also fall within the scope of the present invention.

  The present invention is a method for producing a polycarbonate by condensing di-t-butyl tricarbonate and a polyhydric phenol to obtain a polycarbonate. The condensation reaction is usually performed in an inert gas in the presence of a solvent. For example, nitrogen gas or argon gas can be used as the inert gas. Moreover, as a solvent, tetrahydrofuran, chloroform, diethyl ether, a methylene chloride, acetonitrile, acetone etc. can be used, for example. In addition, it is preferable to use the solvent immediately after dehydration. This is because water mixed in the solvent may inhibit the reaction.

  The value of the ratio of the amount of di-t-butyl tricarbonate used relative to the amount of polyhydric phenol used in this condensation reaction (number of moles of di-t-butyl tricarbonate / number of moles of polyhydric phenol) is 0. It is preferably 1 to 1.0, more preferably 0.3 to 0.7, and particularly preferably 0.5. If the value of the ratio is outside this range, polycarbonate tends to be difficult to obtain.

  The amount of the solvent used is preferably such an amount that the concentration of di-t-butyltricarbonate is 0.1 to 10 mol / L, and more preferably 0.5 to 3.0 mol / L. It is particularly preferable that the amount be 1.0 to 2.0 mol / L. When the concentration of di-t-butyltricarbonate is less than 0.1 mol / L, the condensation reaction may be remarkably slow. On the other hand, if the concentration of di-t-butyltricarbonate is less than 10 mol / L, the raw material may not be completely dissolved.

  The reaction temperature for the condensation reaction is preferably -20 to 60 ° C, more preferably -10 to 40 ° C, and particularly preferably 0 to 25 ° C. If the reaction temperature is less than -20 ° C, the condensation reaction may not proceed sufficiently. On the other hand, if it exceeds 60 ° C., di-t-butyltricarbonate may be decomposed to lower the yield. The reaction time is preferably 1.0 hour or longer, more preferably 2.0 hours or longer, and particularly preferably 3.0 hours or longer. If the reaction time is less than 1.0 hour, the condensation reaction may not proceed sufficiently.

  In the present specification, di-t-butyltricarbonate refers to a compound represented by the following formula (3).

  Di-t-butyl tricarbonate can be synthesized, for example, by the following formula (4). More specifically, after reacting potassium t-butyl alkoxide with carbon dioxide, di-t-butyl tricarbonate can be synthesized by further reacting with triphosgene.

  Moreover, as a polyhydric phenol used for a condensation reaction, it is preferable to use the compound represented by the following general formula (1) or (2).

（前記一般式（１）中、Ｒ^１は、炭素数１〜６のアルキル基を示す。）

(In the general formula (1), R ¹ represents an alkyl group having 1 to 6 carbon atoms.)

（前記一般式（２）中、Ｒ^２は、炭素数１〜６のアルキル基を示す。）

(In the general formula (2), R ² represents an alkyl group having 1 to 6 carbon atoms.)

Specific examples of the alkyl group having 1 to 6 carbon atoms represented by R ¹ in the general formula (1) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. Among these, a methyl group is preferable. Further, in the general formula (2), the alkyl group having 1 to 6 carbon atoms represented as ^{R 2,} specifically, in the general formula (1), alkyl having 1 to 6 carbon atoms represented as ^{R 1} The same thing as a group is mentioned.

  When the compound represented by the general formula (1) is used as the polyhydric phenol, a hyperbranched polymer polycarbonate (hereinafter referred to as “HBPC”) represented by the following general formula (5) can be produced. it can. Hyperbranched polymers usually have low melt viscosity and birefringence, high solubility in various organic solvents, amorphous properties, and many functionalities compared to linear polymers of the same molecular weight. It is possible to introduce a functional group and has excellent film forming properties.

（前記一般式（５）中、Ｒ^１は、炭素数１〜６のアルキル基を示し、ｎ、ｍは繰り返し単位数を示す。）

(In the general formula (5), R ¹ represents an alkyl group having 1 to 6 carbon atoms, and n and m represent the number of repeating units.)

  The polystyrene-reduced number average molecular weight (hereinafter referred to as “Mn”) by size exclusion chromatography of HBPC (hereinafter referred to as “SEC”) is preferably 1,000 to 50,000, More preferably, it is 000-30,000, and it is especially preferable that it is 5,000-20,000. Further, the ratio (Mw / Mn) of Mn to the weight average molecular weight (hereinafter referred to as “Mw”) is preferably 1.1 to 5.0, and more preferably 1.15 to 3.0. It is preferably 1.4 to 2.0.

  The refractive index of HBPC is preferably 1.50 or more, more preferably 1.55 or more, and particularly preferably 1.57 or more. If the refractive index is less than 1.50, use as an optical material may be difficult.

The birefringence of HBPC is preferably 1.0 or less, more preferably 5.0 × 10 ⁻³ or less, and particularly preferably 1.0 × 10 ⁻⁴ or less. If the birefringence is more than 1.0, it may be difficult to use HBPC as an optical material such as an optical lens.

  Thus, HBPC has a low birefringence and a high refractive index. HBPC has high solubility in various organic solvents, is amorphous, and has a large number of phenolic hydroxyl groups at its ends, so it is possible to introduce many functional functional groups. It has membrane properties. Therefore, the use as optical materials, such as an optical lens, and resist resin can be anticipated.

  On the other hand, when the compound represented by the general formula (2) is used, a linear polycarbonate (hereinafter referred to as “LPC”) represented by the following general formula (6) can be produced. LPC has a higher refractive index than HBPC because there is no decrease in molecular density due to the introduction of a branched skeleton.

（前記一般式（６）中、Ｒ^２は、炭素数１〜６のアルキル基を示し、ｌは繰り返し単位数を示す。）

(In the general formula (6), R ² represents an alkyl group having 1 to 6 carbon atoms, and l represents the number of repeating units.)

  MPC in terms of polystyrene by SEC of LPC is preferably 1,000 to 20,000, more preferably 2,000 to 15,000, and particularly preferably 3,000 to 10,000. . The ratio of Mn to Mw (Mw / Mn) is preferably 1.1 to 3.0, more preferably 1.15 to 2.0, and 1.2 to 1.8. It is particularly preferred.

  The refractive index of LPC is preferably 1.50 or more, more preferably 1.52 or more, and particularly preferably 1.53 or more. If the refractive index is less than 1.50, use as an optical material may be difficult.

The birefringence of LPC is preferably 1.0 or less, more preferably 5.0 × 10 ⁻² or less, and particularly preferably 5.0 × 10 ⁻³ or less. If the birefringence index exceeds 1.0, it may be difficult to use LPC as an optical material such as an optical lens.

  Thus, LPC has a low birefringence and a high refractive index. In addition, LPC has high solubility in various organic solvents, is amorphous, and has a phenolic hydroxyl group at its end, so that a functional functional group can be introduced, and excellent film-forming properties can be obtained. Have. Therefore, the use as optical materials, such as an optical lens, and resist resin can be anticipated.

  In order to use polycarbonate as a resist resin, examples of functional functional groups that can be introduced by reacting with a phenolic hydroxyl group at the end include a methacryloyl group. The method for introducing the methacryloyl group is not particularly limited, and for example, it can be introduced by reacting methacrylic anhydride with polycarbonate in the presence of a basic solvent. Specific examples of the basic solvent include pyridine and triethylamine.

  A polycarbonate having a methacryloyl group introduced is prepared by dissolving a photopolymerization initiator in a solvent such as tetrahydrofuran together with a photopolymerization initiator and, if necessary, a photoresist, and applying and drying the prepared photoresist. Can be used as The resist resin can be photocured by irradiating light using, for example, an ultra-high pressure mercury lamp. Specific examples of the diluent include 2-hydroxyethyl methacrylate. By using such a diluent, a change in film thickness due to photocuring can be reduced.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified. Moreover, the measuring method of various physical-property values and the evaluation method of various characteristics are shown below.

  [Number average molecular weight (Mn) and weight average molecular weight (Mw)]: A polystyrene equivalent value was measured by size exclusion chromatography using a model number “HLC-8220” manufactured by Tosoh Corporation as a column.

  [Nuclear Magnetic Resonance Spectrum]: Measurement was performed at 600 MHz using a trade name “JNM-α-600” (manufactured by JEOL).

  [Infrared absorption spectrum]: Measurement was performed using a trade name “FT / IR-420” (manufactured by JASCO).

  [Refractive index]: Measured using a trade name “DHAOLX Ellipsonder” (manufactured by Mizojiri Optics).

  [Birefractive index]: Measurement was carried out using a trade name “EPL-FL” (manufactured by Mizojiri Optics).

(Synthesis Example 1)
25 g of potassium tert-butoxide dissolved in 600 mL of tetrahydrofuran was added to a nitrogen-substituted 1 L three-necked eggplant flask equipped with a dropping funnel and a three-way cock. Carbon dioxide was blown in while maintaining the temperature at 0 ° C., and the mixture was stirred for 3 hours until the viscosity of the solution did not change. Next, 11 g of triphosgene dissolved in 100 mL of tetrahydrofuran was dropped from the dropping funnel over 1 hour, and then stirred at room temperature for 12 hours in a carbon dioxide atmosphere. After the precipitated salt was separated by filtration, the filtrate was concentrated and recrystallized with n-hexane to obtain 10 g of di-t-butyl tricarbonate as white needle crystals (yield 35%).

Example 1
To a 10 mL flask purged with nitrogen was added 263 mg of di-t-butyl tricarbonate, 290 mg of 1-phenyl-1,1-bis (4-hydroxyphenyl) ethane, and 1 mL of dehydrated tetrahydrofuran, and the mixture was stirred at room temperature for 48 hours. did. Thereafter, 1 mL of tetrahydrofuran was added to the reaction solution, and precipitation with methanol was performed to obtain 257 mg of a white powder of linear polycarbonate (yield 77%). The number average molecular weight of polystyrene conversion by size exclusion chromatography of the obtained linear polycarbonate is 2189, and the ratio (Mw / Mn) of the number average molecular weight (Mn) to the weight average molecular weight (Mw) is 1.67. Met.

¹ H nuclear magnetic resonance spectrum data and infrared absorption spectrum data of the obtained linear polycarbonate are described.
δ (ppm): 9.33 (s, 1H), 7.31 to 7.03 (m, 80H), 6.84 to 6.67 (q, 4H), 2.16 (d, 19H), 1 .48 (s, 6H)
ν (cm ⁻¹ ): 3450, 2978, 1775, 1503, 1231

(Examples 2 to 6)
A linear polycarbonate was obtained in the same manner as in Example 1 except that the stirring time and reaction temperature were changed to the conditions shown in Table 1. Table 1 shows the polystyrene-equivalent number average molecular weight and the ratio of the number average molecular weight (Mn) to the weight average molecular weight (Mw) (Mw / Mn) of each linear polycarbonate obtained by size exclusion chromatography.

  Since each produced linear polycarbonate has a hydroxyl group at its terminal, it is possible to introduce a functional functional group, and use as a resist resin can be expected.

(Example 7)
To a 10 mL flask purged with nitrogen, 263 mg of di-t-butyl tricarbonate, 306 mg of 1,1,1-tris (4-hydroxyphenyl) ethane, and 1 mL of dehydrated tetrahydrofuran were added, and the mixture was stirred at room temperature for 3 hours. Thereafter, 1 mL of tetrahydrofuran was added to the reaction solution to obtain a hyperbranched polycarbonate.

¹ H nuclear magnetic resonance spectrum data and infrared absorption spectrum data of the obtained hyperbranched polycarbonate are described.
δ (ppm): 9.37 to 9.21 (m, 3H, Ar—OH), 7.33 to 6.63 (m, 12H, aromatic-H)
[nu] (cm _< ^-1 >): 3450 ([nu] _O-H ), 2971 ([nu] _C-H , aromatic), 1775 ([nu] _{C = O} , carbonate), 1510 ([nu] _{C = C} , aromatic), 1231 ([nu] _C- ). _O-C , aromatic)

(Reference Examples 1-5)
A hyperbranched polycarbonate was obtained in the same manner as in Example 7 except that the stirring time and reaction temperature were changed to the conditions shown in Table 2.

  The produced hyperbranched polycarbonate has a hydroxyl group at its end, can introduce a functional functional group, and can be expected to be used as a resist resin.

  The polycarbonate produced by the polycarbonate production method of the present invention can be expected to be applied as an optical material or a resist resin.

Claims (3)

Di-t-butyl tricarbonate;
A method for producing a polycarbonate by condensing a polyhydric phenol to obtain a polycarbonate. The method for producing a polycarbonate according to claim 1, wherein the polyhydric phenol is a compound represented by the following general formula (1).

(In the general formula (1), R ¹ represents an alkyl group having 1 to 6 carbon atoms.) The method for producing a polycarbonate according to claim 1, wherein the polyhydric phenol is a compound represented by the following general formula (2).

(In the general formula (2), R ² represents an alkyl group having 1 to 6 carbon atoms.)