JPH09278875A - Production of polycarbonate resin mixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polycarbonate resin having a high molecular weight, excellent heat stability and hydrolysis resistance and improved hue by a melting process. SOLUTION: In obtaining a polycarbonate resin mixture by adding an antioxidant to a polycarbonate resin obtained by polycondensing a dihydric phenol with a carbonic diester in a molten state in the presence of a transesterification catalyst, the polycarbonate resin mixture is kept at a terhperature equal to or higher than the glass transition temperature of the polycarbonate resin for a certain or longer drying time.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polycarbonate resin mixture obtained by adding an antioxidant to a polycarbonate obtained by polycondensing a dihydric phenol and a carbonic acid diester in the presence of a transesterification catalyst. The present invention relates to a method for producing a polycarbonate resin mixture having excellent heat resistance stability, hydrolysis resistance, and hue which can be obtained by keeping the mixture at a glass transition temperature of the polycarbonate resin or lower for a certain period of time or longer.

[0002]

BACKGROUND OF THE INVENTION High molecular weight polycarbonate resins obtained from the process for producing a polycarbonate resin mixture of the present invention are
A general purpose engineering thermoplastic with a wide range of applications, especially for injection molding or as a glass sheet alternative to glazing.

Polycarbonate resins are generally said to have excellent heat resistance, transparency and impact resistance. As a method for producing a polycarbonate resin, a phosgene method in which a dihydric phenol and phosgene are subjected to interfacial polycondensation to react, or a melt transesterification method in which a dihydric phenol and a carbonic acid diester are reacted in a molten state is generally known. .

As a typical example of the melt transesterification method, an ester exchange catalyst is added to a dihydric phenol and a carbonic acid diester to synthesize a prepolymer while distilling phenol under heating and reduced pressure, and finally to a high vacuum. Bottom 290
A method of obtaining a high molecular weight polycarbonate resin by heating above ℃ to distill phenol to obtain a high molecular weight polycarbonate resin is described in US Pat. No. 4,345,062.
It is publicly known by the number.

Further, in the melt transesterification method, in order to proceed the reaction efficiently, the prepolymer is synthesized in a tank reactor having an ordinary stirring blade in the initial stage of the reaction, and then a self-cleaning type vented extrusion is carried out. It is also possible to perform polycondensation reaction using a machine-like device.
It is known from Japanese Patent Publication No. 9552.

However, unlike other engineering plastics, the production of high-molecular-weight polycarbonate resin requires a high temperature of 270 ° C. or higher as a reaction condition because it has a very high melt viscosity. In order to distill off the high-valent phenol compound from the high-viscosity substance, a high vacuum of about 1 to 10 ⁻² Torr is required, and it has been considered difficult in terms of equipment.

[0007]

As a polymerization catalyst to be used in the production of a polycarbonate resin by a transesterification method, a hydroxide, hydride, oxide, alcoholate or carbonate of an alkali metal or an alkaline earth metal is generally used. , Acetate and the like. However, when these basic catalysts remain in the final product, there has been a problem that the heat resistance stability, hydrolysis resistance, molding retention stability, weather resistance hue, etc. of the polycarbonate resin are significantly reduced.

As one method for solving these problems, there is a method of adding a third component to the reaction solution to weaken the effect of the basic catalyst. As an example, British Patent Publication 1
It is disclosed in 031512 that this problem can be solved by adding a substance that binds to a base to the molten resin near the end point of the transesterification reaction to neutralize the basic catalyst. However, these methods have a problem that it is difficult to uniformly mix a small amount of an additive with a resin having a high melt viscosity in a short time.

[0009] Another solution is to change the type of catalyst. As an example thereof, Japanese Examined Patent Publication No. 46-20504 discloses a method of using tetrafluoroborate or hydroxyfluoroborate as a catalyst. However, in this case, since the catalyst contains halogen atoms, there is a concern that the apparatus may be corroded or the physical properties of the resin may be deteriorated.

Further, JP-A-2-124934 discloses that a nitrogen-containing basic compound and an alkali (earth) are used as a polymerization catalyst.
It is disclosed that the decomposition reaction can be prevented by using a metal compound and boric acid (ester). However, in this case, there was a problem that three kinds of polymerization catalysts were used.

Therefore, in the presence of a transesterification catalyst, 2
There has been a strong demand for the appearance of a simple production method which retains excellent heat resistance and hydrolysis resistance of a polycarbonate resin obtained by polycondensing a dihydric phenol and a carbonic acid diester, and retains a good hue.

[0012]

The present inventors have obtained a polycarbonate resin mixture by adding an antioxidant to a polycarbonate resin obtained by polycondensing a dihydric phenol and a carbonic acid diester in the presence of a transesterification catalyst. When
It was discovered that the problems associated with the above-mentioned conventional techniques can be solved by maintaining the polycarbonate resin mixture at a glass transition temperature of the polycarbonate resin or lower for a certain period of time or longer, and the present invention has been completed. It was.

Particularly, it is preferable to produce the polycarbonate resin by using at least one catalyst selected from the group consisting of basic nitrogen compounds, alkali metals, alkaline earth metals, boric acid and boric acid esters as the transesterification catalyst. .

Further, the basic nitrogen compound is preferably 4,4-dimethylaminopyridine, and the alkali metal is preferably lithium borate or lithium hydroxide. When these polymerization catalysts are compared with other basic compounds, they are the same in terms of accelerating the transesterification reaction, but when 4,4-dimethylaminopyridine, lithium borate and lithium hydroxide are used, polycarbonate is used. The mixture of the resin and the antioxidant added is below the glass transition temperature of the polycarbonate resin, and if the drying time is maintained for a certain period of time or more, the decomposition reaction of the polycarbonate resin due to heat and water is significantly suppressed, and the heat resistance stability, Excellent in hydrolysis resistance and hue improvement.

That is, in the present invention, when a polycarbonate resin mixture is obtained by adding an antioxidant to a polycarbonate resin obtained by polycondensing a dihydric phenol and a carbonic acid diester in the presence of a transesterification catalyst, the polycarbonate resin mixture is The present invention relates to a method for producing a polycarbonate resin mixture which is excellent in thermal stability, hydrolysis resistance and hue by maintaining a drying time of not less than a glass transition temperature of a polycarbonate resin for a certain time or longer.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Representative examples of the dihydric phenol include compounds represented by any of the following general formulas.

[0017]

Embedded image

Embedded image

Embedded image

Embedded image In addition, R ¹ , R ² , R ³ , R ⁴ and R ⁵ in the general formula are respectively
A hydrogen atom or a linear or branched alkyl group having 1 to 8 carbon atoms, or a phenyl group, X is a halogen atom, n is a positive integer of 0 to 4, and m is 1 to 4
Is a positive integer.

Of the general formula

Embedded image The following compounds may be mentioned as dihydric phenols classified into 2,2-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) -4-methylpentane, 2,2-bis- (4-hydroxyphenyl) octane, 4,4'-dihydroxy-2,2,2-tri Phenylethane, 2,2-bis- (3,5-dibromo-4-hydroxyphenyl) propane, etc.

Of the general formula

[Chemical 6] The following compounds may be mentioned as dihydric phenols classified into 2,2-bis- (4-hydroxy-3-methylphenyl) propane, 2,2-bis- (4-hydroxy-3-isopropylphenyl) propane, 2,2-bis- (4-hydroxy-3-sec.-butylphenyl) propane, 2,2-bis- (4-hydroxy-3-) tert.-butylphenyl) propane and the like.

Of the general formula

Embedded image The following compounds may be mentioned as dihydric phenols classified into 1,1-bis- (4-hydroxyphenyl)
-P-diisopropylbenzene, 1,1-bis- (4-hydroxyphenyl) -m-diisopropylbenzene and the like.

Of the general formula

Embedded image The following compounds may be mentioned as dihydric phenols classified into 1,1-bis- (4-hydroxyphenyl)
Cyclohexane and the like. Of these, 2,2-bis- (4-hydroxyphenyl) propane is particularly preferable.

Further, in the general formula

Embedded image

Embedded image

Embedded image

[Chemical 12] It is also possible to produce a copolycarbonate resin in which two or more dihydric phenols selected from the compounds represented by are combined.

As a typical example of carbonic acid diester,
Examples thereof include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, bis (cyanophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, diethyl carbonate, dimethyl carbonate, dibutyl carbonate and dicyclohexyl carbonate. Of these, diphenyl carbonate is particularly preferable. When the polycarbonate is produced in the present invention, the above carbonic acid diester needs to be equimolar with the dihydric phenol present in the reaction system. Generally, in order to produce a high molecular weight polycarbonate resin, 1 mol of the carbonate compound and 1 mol of the dihydric phenol must react. For example, when diphenyl carbonate is used, 2 mol of phenol is produced by the above reaction. These 2 moles of phenol are distilled out of the reaction system. However, when distilling the produced monohydric phenol compound out of the system in order to promote the reaction, the carbonic acid diester that is a monomer may also be distilled off at the same time.
It is preferably used in an amount of 1.05 to 1.5 mol with respect to 1 mol of the hydric phenol.

As the antioxidant mixed with the polycarbonate resin in the present invention, a commercially available hindered phenol compound is used. Typical examples of the hindered phenol compound include octadecyl-3- (3,5-di-tert.-butyl-4-hydroxyphenyl) propionate and triethyleneglycol-bis [3- (3-tert.-butyl-5-methyl-4-hydroxyphenyl) propionate. ], 1,6-hexanediol [3- (3,5-di-tert.-butyl-4-hydroxyphenyl) propionate], pentaerythrityl-tetrakis [3
-(3,5-Di-tert.-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t
ert. -Butylanilino) -1,3,5-triazine, 2,2-thiodiethylenebis [3- (3,5-ditert.-butyl-4-hydroxyphenyl) propionate] and the like. Further, the above-mentioned hindered phenol compounds can be used in a combination of two or more kinds. The addition amount of the antioxidant is preferably in the range of 0.01 to 1% by weight with respect to the polycarbonate resin. Further, it is preferably 0.05 to 0.5% by weight with respect to the polycarbonate resin. Here, the addition amount is 0.0
If it is less than 1% by weight, it has no effect on heat stability, hydrolysis resistance and hue improvement, and if it exceeds 1% by weight, the melt flow index value becomes large and impact resistance and hue are lowered, which is not preferable.

When a polycarbonate resin mixture obtained by adding an antioxidant to a polycarbonate resin is kept at a temperature not higher than the glass transition temperature of the polycarbonate resin for a drying time of more than a certain time, if the drying temperature is less than 120 ° C., it is contained in the polycarbonate resin. Not enough water can be distilled off 1
When it exceeds 20 ° C, the physical properties of the polycarbonate resin mixture are adversely affected. Further, if the drying time is less than 4 hours, the water contained in the polycarbonate cannot be sufficiently distilled off, and even if the drying is carried out for a long time, energy is wasted and the manufacturing cost is increased, which is not preferable. The drying time is preferably 10 hours to 24 hours. Further, a polycarbonate resin mixture having the best production method in which a polycarbonate resin mixture obtained by adding an antioxidant to a polycarbonate resin obtained by melt polycondensation is dried and maintained at 120 ° C. or lower, which is lower than the glass transition temperature of the polycarbonate resin, for 4 hours or more. Is a manufacturing method.

[0026] The amount of the divalent phenol 1 10 ^-1 mol preferably from 10 ^-6 mol per mol present in the reaction system of the basic nitrogen compound used as a catalyst, further, preferably from 10 ^-4 mol 10 ^-2 mol. Where 1
0 ^-6 slow rate of polymerization less polycarbonate resin catalysis is less than the molar Shigetoshi, leading to deterioration of physical properties of the polycarbonate resin since the catalyst amount is more remaining in the polycarbonate resin to produce an excess of 10 ^-1 mole.

Further, alkali metal, alkaline earth metal,
The amount of adding at least one or more catalysts selected from the group consisting of boric acid and boric acid esters, from 10 ^{@ 8} moles relative to the dihydric phenol 1 mole present in the reaction system 1
0 ^{- 2} mol is preferred. Further, it is preferably ^10-6 mol to ^10-3 mol. ^{10-2 8} alkali metal is less than molar, alkaline earth metal, at least one kind of no addition effect of the catalyst is selected from the group consisting of boric acid and boric acid esters, the polycarbonate resin to produce a greater than 10 ^-2 moles Since the amount of the remaining catalyst increases, the physical properties of the polycarbonate resin deteriorate.

[0028]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited by these examples.

(Synthesis example 1) 4,560 g (20 mol) of 2,2-bis (4-hydroxyphenyl) propane and 43 diphenyl carbonate were placed in a nickel-clad tank reactor.
91.5 g (20.5 mol) and N, N-dimethyl-4-aminopyridine 489 mg (4 × 10 ⁻³ mol) were added, and the mixture was melted at 160 ° C. under nitrogen, stirred for 1 hour, and gradually heated under reduced pressure. Finally, polycondensation reaction is performed at 1 Torr and 270 ° C. for 4 hours, and the produced phenol is distilled off.
Furthermore, a colorless transparent polycarbonate resin was obtained by reacting for 50 minutes with a biaxial self-cleaning reactor. The viscosity average molecular weight (Mv) of the obtained polycarbonate resin was Mv = 24,000. The viscosity average molecular weight is measured by measuring the intrinsic viscosity [η] of the methylene chloride solution at 20 ° C. using an Ubbelohde viscometer, and using the following formula:
Was calculated. [Η] = 1.11 × 10 ^over 4 ^{(Mv) 0.82} Further, as an index indicating the degree of coloring, the use of YI (yellow index value) was YI = 2.0. YI
The value is measured by making a sheet with a thickness of 2 mm and a size of 50 mm × 50 mm by the hot press quenching method, and using Nippon Denshoku Co., Ltd. 30
It was measured using 0A.

(Synthesis example 2) 4,560 g (20 mol) of 2,2-bis (4-hydroxyphenyl) propane and diphenyl carbonate 43 were placed in a nickel-clad tank reactor.
91.5 g (20.5 mol), meta an aqueous solution of lithium borate · dihydrate 17 mg (2 × 10 ^-4 mol) was added, after thawing under nitrogen at 180 ° C., and stirred for 1 hour, the temperature while the pressure was gradually reduced The mixture was heated and finally subjected to polycondensation reaction at 1 Torr and 270 ° C. for 4 hours, the produced phenol was distilled off, and further reacted for 45 minutes in a biaxial self-cleaning reactor to obtain a colorless transparent polycarbonate resin. The viscosity average molecular weight (Mv) of the obtained polycarbonate resin is Mv
= 25,000 and YI = 1.9.

(Synthesis Example 3) 4,560 g (20 mol) of 2,2-bis (4-hydroxyphenyl) propane and 43 of diphenyl carbonate were placed in a nickel-clad tank reactor.
91.5 g (20.5 mol), tetramethylammonium hydroxide 445 mg (0.005 mol), sodium 0.8 mg (2 × 10 ^-5 mol) hydroxide, 3.1 mg of boric acid (5 × 10 ^-5 mol ) Is added, and 160
After melting at ℃, stir for 1 hour, gradually raise the temperature while reducing the pressure, and finally carry out a polycondensation reaction at 1 Torr, 270 ℃ for 4 hours, distill off the phenol produced, and further a twin-screw self-cleaning reactor. By reacting for 45 minutes at
A colorless and transparent polycarbonate resin was obtained. The viscosity average molecular weight (Mv) of the obtained polycarbonate resin is Mv = 2
It was 9,500 and YI = 25.

(Synthesis Example 4) 4,560 g (20 mol) of 2,2-bis (4-hydroxyphenyl) propane and 43 diphenyl carbonate were placed in a nickel-clad tank reactor.
91.5 g (20.5 mol), tetramethylammonium hydroxide 445 mg (0.005 mol), sodium hydroxide 0.8mg of (2 × 10 ^-5 mol) was added,
After melting under nitrogen at 160 ° C., stirring for 1 hour, gradually raising the temperature while reducing the pressure, finally polycondensing at 1 Torr, 270 ° C. for 4 hours, distilling off the produced phenol, and further biaxial self-cleaning type A colorless transparent polycarbonate resin was obtained by reacting for 45 minutes in a reactor. The viscosity average molecular weight (Mv) of the obtained polycarbonate is Mv =
It was 29,000. YI = 2.3.

[0033]

Example 1 0.1 g of pentaerythrityl-tetrakis [3- (3,5-ditertalibutyl-4-hydroxyphenyl) propionate] was added to 100 g of the polycarbonate resin obtained in (Synthesis example 1) using a tumbler. The mixture was thoroughly mixed and dried in a dryer at 120 ° C. for 12 hours.

[0034]

Example 2 0.2 g of triethylene glycol-bis- (3-tert.-butyl-5-methyl-4-hydroxyphenyl) propionate] was thoroughly mixed with 100 g of the polycarbonate resin obtained in (Synthesis example 2) using a tumbler. And dried in a dryer at 120 ° C. for 10 hours.

[0035]

Example 3 100 g of the polycarbonate resin obtained in (Synthesis example 3) was mixed with 1,6-hexanediol [3- (3,
5-Gee tert. 0.1 g of -butyl-4-hydroxyphenyl) propionate] was thoroughly mixed using a tumbler, and dried at 120 ° C for 10 hours.

[0036]

Example 4 100 g of the polycarbonate resin obtained in (Synthesis example 4) was added with 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert.-butylanilino) -1,3,5-triazine]. Thoroughly mix 25 g using a tumbler and dry at 120 ° C.,
It was dried for 10 hours.

[0037]

Example 5 100 g of the polycarbonate resin obtained in (Synthesis example 2) was mixed with 1,6-hexanediol [3- (3,
5-Gee tert. 0.5 g of -butyl-4-hydroxyphenyl) propionate] was thoroughly mixed using a tumbler and dried in a dryer at 120 ° C for 12 hours.

[0038]

Example 6 To 100 g of the polycarbonate resin obtained in (Synthesis example 1), 0.5 g of 2,2-thio-diethylenebis [3- (3,5-di-tert.-butyl-4-hydroxyphenyl) propionate] was placed in a tumbler. The mixture was thoroughly mixed and dried in a dryer at 120 ° C. for 12 hours.

[0039]

[Comparative Examples 1 to 4] The polycarbonate resins obtained in (Synthesis Examples 1 to 4) were dried in a dryer at 120 ° C for 10 hours.

The results are shown in Table 1. The number of cuts shown in Table 1 is shown below. The number of cuts (s _t ) after t days at a heating temperature of 160 ° C. is represented by the following formula. s _t = (M _o
/ _M t) -1 where _{M o} and _{M t} represents a viscosity-average molecular weight of the polycarbonate resin after each heating before and day t.

[0041]

[Table 1] It can be seen from Table 1 that the examples of the invention of the present application show very little decrease in the number of cuts, which is an index of heat resistance, as compared with the conventional comparative examples, and are very excellent as general-purpose resins.

[0042]

The polycarbonate resin obtained from the method for producing the polycarbonate resin mixture of the present invention has excellent heat resistance stability, hydrolysis resistance and hue, and has a wide range of applications, particularly for injection molding or window glass replacement. It is extremely useful as a general-purpose engineering thermoplastic such as glass sheet.

Claims (4)

[Claims] 1. When a polycarbonate resin mixture is obtained by adding an antioxidant to a polycarbonate resin obtained by melt polycondensation of a dihydric phenol and a carbonic acid diester in the presence of a transesterification catalyst, the polycarbonate resin mixture is a polycarbonate. A method for producing a polycarbonate resin mixture, which comprises maintaining a drying time of a certain time or longer at a temperature not higher than the glass transition temperature of the resin. 2. A transesterification catalyst comprising at least one catalyst selected from the group consisting of basic nitrogen compounds, alkali metals, alkaline earth metals, boric acid and boric acid esters. A process for producing the described polycarbonate resin mixture. 3. The method for producing a polycarbonate resin mixture according to claim 1 or 2, wherein the amount of the antioxidant added is in the range of 0.01 to 1% by weight with respect to the polycarbonate resin. . 4. When a polycarbonate resin mixture is obtained by adding an antioxidant to a polycarbonate resin obtained by melt polycondensation, the polycarbonate resin mixture is mixed with 12 parts of the polycarbonate resin mixture.
The method for producing a polycarbonate resin mixture according to claim 1, 2, or 3, wherein the drying time is kept at 0 ° C or lower for more than 4 hours.