JPS6343924A - Production of polycarbonate resin as optical material - Google Patents

Abstract

PURPOSE:To obtain an optical material having a stabilized MW and excellent heat and hydrolysis resistance, by transesterifying a dihydroxy compound with a diallyl carbonate in the presence of a specified catalyst and a monofunctional organic compound as a terminal modifier. CONSTITUTION:The production of a polycarbonate by transesterifying a dihydroxy compound with a diallyl carbonate is carried out in the following way. At least one catalyst selected from among an alkali metal borohydride, a tetraalkylammonium borohydride and a tetraalkylammonium halide is used as a catalyst and a monofunctional organic compound of the formula is used as a chain terminator/modifier. The amount of the chain terminator added is such that it is effective in preparing an aromatic polycarbonate having a viscosity-average MW of, preferably, about 10,000-25,000.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a method for producing a polycarbonate resin suitable for optical materials, particularly optical disks, which has excellent heat resistance and hydrolysis resistance, and has a stable molecular weight.

(Prior Art and its Problems) Polycarbonate, which has excellent transparency and mechanical properties as an optical material, has already been widely put into practical use. It goes without saying that materials for recording media, especially materials for optical disks, have excellent transparency and mechanical properties, but it is hoped that materials with even lower birefringence, superior long-term recording stability, and high reliability will emerge. It is rare.

It is a well-known fact that polycarbonate end-capped using an oil agent or a terminal capping agent gives a polymer with good color and thermal stability as seen in Japanese Patent Publication No. 46-41621. In other words, non-endcapped polycarbonate has free phenolic end groups and/or phenyl-carbonate end groups, especially polymers with free phenolic end groups have poor thermal stability and are easily degraded by heat. It is also susceptible to deterioration due to hydrolysis under high humidity conditions. Polycarbonate is also unstable in molecular weight, and when subjected to thermal degradation due to reaction with a polymer having a phenyl carbonate end group, the molecular weight changes, making it undesirable as an optical material requiring precision molding.

Setting a stable molecular weight that does not leave any residual strain is an important issue, especially from the perspective of lowering the birefringence of molded products.

In addition, the obtained polycarbonate has different hues and colors due to its physical properties.
In addition to good thermal stability, there is a strong demand for excellent hydrolysis resistance from the viewpoint of transparency, long-term recording stability, and reliability of disk recording.

The effect of end-capping agents on the properties of polycarbonate is generally not fully understood, and empirical approaches are common in this field in determining whether a particular compound or group of compounds will act effectively as a polycarbonate end-capping agent. This is a common practice. Furthermore, the particular compound must not only function as a terminal capping agent, but also must not adversely affect the practically advantageous properties and characteristics of the polycarbonate when incorporated into the carbonate polymer chain as a terminal group. It's even more complicated. That is, even though certain compounds may be effective as end-capping agents, they are of no practical use if they adversely affect some of the desirable and useful properties of the polycarbonate.

In particular, polycarbonate used as a disc material is subject to severe restrictions.

Therefore, there is a need for a terminal capping agent whose molecular weight is tightly controlled and which substantially retains nearly all of the other advantageous properties of polycarbonate, while at the same time having improved hydrolysis resistance, heat resistance, birefringent flow properties, and enhanced end capping agents. ing.

(Means for Solving Problems) As a result of intensive studies aimed at providing such a material, the present invention has revealed that it can be obtained by a transesterification method using a specific catalyst system, a specific terminal stopper, and a specific molecular weight regulator. The inventors discovered that polycarbonate is a material that satisfies the above-mentioned performance requirements, and completed the present invention.

The present invention is a method for producing a polycarbonate resin which has excellent heat resistance and hydrolysis resistance and has a stable molecular weight and is suitable for optical materials, especially optical disks. That is, in producing polycarbonate from a dioxy compound and diallyl carbonate by transesterification reaction, at least one catalyst selected from alkali metal borohydride, tetraalkylammonium polyhydride, and tetraalkylammonium hafide is used as a catalyst. A method for producing an optical material polycarbonate resin, which comprises terminal modification using a monofunctional organic compound represented by the following general formula as a terminal stopper and a molecular weight regulator.

The general formula is (wherein R represents hydrogen or a linear or branched alkyl group having 1 to 12 carbon atoms).

The aromatic polycarbonate resin used in carrying out the present invention is a carbonate homopolymer of dihydric phenol, 2
These are carbonate copolymer resins of different types of dihydric phenols or copolymer resins of such dihydric phenols and aliphatic diols.

The content of the present invention will be explained in detail below.

The divalent phenol used in carrying out the present invention includes:
It is a known dihydric phenol whose reactive groups are two phenolic hydroxyl groups. Some of these are represented by general formulas. In the formula, A is a divalent hydrocarbon group containing 1 to about 15 carbon atoms: a substituted divalent hydrocarbon group containing 1 to about 15 carbon atoms, and halogen, -5-1-S-S
-1]1(1 -S-1-S-1-〇-1 or -C-, each X is independently a substituent such as hydrogen, halogen, alkyl group of 1 to about 8 carbon atoms, a monovalent carbon group, an aryl group of 6 to 18 carbon atoms, an aralkyl group of 7 to about 14 carbon atoms, an aralkyl group of 7 to about 14 carbon atoms, an oxyalkyl group of 1 to about 8 carbon atoms, or an oxyalkyl group of 6 to about 8 carbon atoms; selected from the group consisting of 18 oxyaryl groups.

m is 0 or 1.

Some representative examples of dihydric phenols that may be used in the practice of this invention include bisphenols, t.
-HydroxyphenyA/)methane, 2,2-bis(4-
Hydroxyphenylene/L/)propane (bispheno-/L)
/ A), 2,2-bis(4-hydroxy-3-methylphenyl)propane, 4,4-bis(4-hydroxypheny/L/)hbutane, 2°2
-bis(4-hydroxy-3,5-dichlorophenylene/I
/) Propane, 2,2-bis(4-hydroxy-3,5
dihydric phenol ethers such as bis(4-hydroxyphenylene/L/) propane, etc.
) ether, bis(3°5-dichloro-4-hydroxypheny/V)ether, etc.; dihydroxydiphenyl example Eva I).

p'-dihydroxydiphenyl, 3,3'-cyclo-4,4'-dihydroxydiphenyl, etc.; dihydroquine arylsulfone examples include bis(4-hydroxyphenylene/
V) Sulfones, bis(3,5-dimethyl-4-hydroxyphenylene/V)sulfones, etc.; dihydroxybenzene, resorcinol, hydroquinone, halo and alkyl-substituted dihydroxybenzenes such as 1,4-dihydroxy-2,5-dichlorobenzene , L4-dihydroxy-3-methylbenzene, etc.; and dihydroxydiphenyl sulfide and sulfoxide such as bis(4-
Hydroxyphenyl
Hydroxyphenylene #) sulfoxide, bis(3,5-
Examples include dibromo-4-hydroxyphenylene/L/) sulfoxide. Other divalent phenols are also available and are disclosed in U.S. Pat.
No. 53008, all of which are incorporated herein by reference. It is of course possible to use two or more different dihydric phenols or a combination of dihydric phenols and glycols.

Carbonate precursors of the present invention include diaryl carbonates and bisphenyl carbonates of dihydric phenols. Examples of diaryl carbonates include bishalide diphenyl carbonate and diphenyl carbonate, and examples of dihydric phenol bisphenyl carbonates include λ2-bis(4-hydroxyphenylene/I/)propane and 2,2-bis(4-hydroxy). -3,5-dichlorophenylene/V) bisphenyl carbonates such as propanehydroquinone. Although all of the above carbonate precursors are useful, diphenyl carbonate is preferred. A branching agent can be used in the synthesis of polycarbonate.

As a branching agent, phloroglycin, 2,6-dimethyl-2.4.6-tri(4-hydroxyphenylene/L/)
Hebutene-3,4,6-dimethy/L'-2゜4,6-
)su(4-hydroxyphenyl)heptene-2,1,
3,5-1-ly(2-hydroxyphenyl)penzol, 1. 1. 1-1-
Li(4-hydroxyphenyl)ethane, 2,6-
Bis(2-hydroxy-5-methylbenzi/L/) -
4-methyl phenol, α
, α′, α′-tri(4-hydroquinpheni#)-1,3,5-)lyisoprobylbenzene, and 3.3
-bis(4-hydroxyaryl-)V)oxind-
Iv (=isatin binuphenol), 5-chloro/l/isatin, 5.7-dicloisatin, 5-bromiisatin, etc. are exemplified.

In the production of the terminal benzoate ester branched polycarbonate resin of the present invention, the amount of polyfunctional phenol used as a branching agent for the divalent phenol I-/L/based compound represented by the above general formula is usually α01 to 3 mol. %, preferably in the range α1 to LO mol%. If it is less than 0.01 mol%, a sufficient branched structure will not be produced, and if it exceeds 3 mol%, high molecular weight substances will be partially produced, which will cause problems such as deterioration of the transparency of the molded product. The object of the invention is not achieved.

The present invention is directed to novel carbonate polymers having specific benzoate esters as end groups. These benzoate ester end groups are represented by the general formula;

R is hydrogen or a linear or branched alkyl having 1 to 12 carbon atoms, and a longer carbon number is not preferred from the viewpoint of heat resistance of the polycarbonate.

The novel carbonate polymer of the present invention comprises reacting at least one compound of the above general formula CI) with a dihydric phenol and a carbonate precursor.

Examples of the substituent R- of the monofunctional organic compound used as the terminal stopper and molecular weight regulator represented by the above general formula (I>) are CH, CH, and CH.

CH, C to CH.

etc.

The end capping agent functions as a molecular weight regulator in the method of the invention.

When added to the reaction vessel, the compound defined above in the general formula (1) not only affects the chain length but also affects the physical properties described above.

Addition of the endstopper can be done initially before adding the carbonate precursor. Alternatively, it can be carried out during the addition of the carbonate precursor and generally at any point of reaction where the degree of polymerization approaches that of the higher polymer. It is preferable to add it from the beginning.

The amount of end capper added is preferably about 10,000
The amount is effective to produce an aromatic polycarbonate having a viscosity average molecular weight of 0 to 25,000. This amount is approximately α1 to 10% as 7% of the dioxy compound used in the reaction.
The mole % preferably varies from about α5 to 8 mole %.

In the practice of the present invention, one of the compounds of general formula (1) above may be used, in which case the end groups of the carbonate polymers will generally all be the same. Also, general formula (I)
Two or more compounds of general formula (I) may be used, in which case the polymer will be in the form of a mixture of various terminal groups depending on the number, amount and type of compounds of general formula (I) used. .

Furthermore, the compounds of general formula CI) may be used in combination with known phenolic or other end-stopping agents.

Transesterification catalysts used in the present invention include alkali metal borohydrides such as potassium borohydride, tetraalkylammonium polyhydrides such as tetrabutylammonium borohydride, tetramethylammonium hydride, and tetrabutylammonium halide. Tetraalkylammonium halides such as are used.

The transesterification catalyst as described above is preferably 10 to 10% based on binuphenol. T
When 10e% is used, the reaction proceeds quickly and is highly active in the production of polycarbonate using a terminal stopper and a molecular weight regulator. The produced polymer has no coloration and has excellent transparency.

Furthermore, the physical properties of polymers obtained using these catalysts exhibit the excellent effects of the terminal capping agent and molecular weight regulator without impairing hydrolysis resistance, thermal stability, etc.

These transesterification catalysts are optimal for the polycarbonate substrate material for disks.

Transesterification catalysts commonly used in polycarbonate synthesis, such as alkali metal alkaline earth metal hydroxides, carbonates, phenolates, etc., are used as the resulting polycarbonate has the characteristics of the present invention, as shown in the specific implementation details. Can be optionally mixed with additives. Examples of such additives include antioxidants, hydrolysis stabilizers, epoxides, phosphorus compounds, phenolic compounds, ultraviolet absorbers such as benzophenones,
These include benzotriazoles, cyanoacrylates, etc., impact modifiers, fillers, color stabilizers, and hardening agents.

Hereinafter, the invention will be specifically explained in detail with reference to Examples.

The methods for measuring the items used to evaluate the polycarbonate obtained according to the present invention are as follows.

(1) Evaluation method of heat resistance: (1) Differential thermogravimetric analyzer (
(manufactured by Rigaku Denki) in a nitrogen stream at a heating rate of 10' (
Thermal decomposition behavior was measured under the conditions of /min. The temperature at which the weight loss due to pyrolysis reaches 5% of the initial weight is T, and the temperature at which the weight loss reaches 10% of the initial weight is 1f-T.

It was used as a guideline for thermal decomposition behavior.

(11) 50 tm x 50 wz by heat press
A sheet with a thickness of
Samples were sampled after 20 and 30 days, and the weight loss rate and average molecular weight of the viscosity were determined to evaluate the state of deterioration of the sample due to heat aging.

The weight of the sample obtained by drying the hot press sheet for 4 hours in a hot air circulation dryer at 120° C. was used as the weight.

(2) Evaluation method of viscosity average molecular weight: Intrinsic viscosity [η] (cle/9) of methylene chloride solution at 20°C
The viscosity was measured using a rope viscosity tube, and the viscosity average molecular weight was calculated using the following formula.

(y7:) = 111 x 10″ (= ■)O,
t 1 (3) Hydrolysis resistance evaluation method: A sheet of 501 fi x 50 silk x 0.6 fl thick was created by heat pressing, and the hemp thread was placed in a constant temperature 1 humidity bath controlled at 90°C and 100% RH. The deterioration of the sample due to hydrolysis was measured over time by measuring changes in viscosity average molecular weight and sheet appearance.

The percentage of the viscosity average molecular weight after 30 days of the hydrolysis test with respect to the initial viscosity average molecular weight was referred to as the 30-day hydrolyzed viscosity average molecular weight retention rate (%), and the change in the sheet appearance after 30 days was used as a measure of hydrolysis resistance.

(4) Melt viscosity and molecular weight stability evaluation method: 120
The melting behavior of the sample pellets dried at 280°C in a hot air circulation dryer for 4 hours at 280°C was measured using a cavilograph manufactured by Toyo Sokki.
The melt flow in seconds was held at 280° C. for 1 hour in a comparatively softened cylinder of a cavilograph, and the stability of the molecular weight was evaluated from the molecular weight retention rate before and after holding. Note that the molecular weight is the viscosity average molecular weight measured by the method (2).

Example 1 Bisphenol A 22 was added to a reactor equipped with a stirrer and replaced with nitrogen.
g, 299 (L 0 mol) and diphenyl carbonate 219.589 (1025”).

-1/shi) and p-tert-butybenzoic acid phenyl 9
．． 919 (5 mo/l' for bispheno-/l/A
%), 1.3.5-1-ly(4-hydroxyphenyl)-benzene (177 g (αOOS mol)) was added, and 16
After melting at 0°C, a solution of 103 mol % based on bisphenol AK was added to catalyst KB to start the reaction. Gradually raise the temperature to 270℃ over 3 hours.
The reaction system pressure was also reduced to 10ffH9 to distill off the produced phenol. Continue α2 at 270℃ for 1 to 2 hours.
A polymer was obtained by reacting at ~0.1 smH9. The obtained polymer had excellent transparency and no coloration, and had a viscosity average molecular weight of 16,100.

Heat resistance test of the obtained polymer by TGA at 90°C.
As a result of the attached hydrolysis test at 100%RH, 160℃
Heat-resistant Examples 2 to 5 Bispheno-/L/A polycarbonate prepared using the method of Example 1 and the terminal capping agent shown in Table 1 Example 6 Bispheno-#A228 was placed in a nitrogen-substituted reactor equipped with a stirrer.
．． 299 (10 mo/L/) and diphenyl carbonate mo/L/) were melted at 160°C, then the catalyst ・(C&
8), NBr is mixed with bisphenol and 10-mol/
Add I/% and start the reaction. Gradually increase the temperature over 2 hours,
The reaction system pressure was reduced to 240C and 40 tlHf, and the produced phenol was distilled off. Here, the reaction system was returned to normal pressure with N, and the molecular weight regulator, P-methyl-benzoic acid 7 z 2 IV I Q 61 f (bispheno-/
5 mo/L/% for 1/A) and restart the reaction. 1
Gradually raise the temperature to 2.70℃ and pressure to 10111H.
The pressure is reduced to 9 and the generated phenol is distilled off. Subsequently, the mixture was reacted with α28α1ffilHf at 270° C. for 1 to 2 hours to obtain a polymer. The obtained polymer is an uncolored polymer with excellent transparency and a viscosity average molecular weight of 20.50.
It was 0.

Example 7 Using the method of Example 6 and using the terminal capping agent and catalyst shown in Table 1, bisphenol--viscosity average molecular weight retention by hydrolysis test in Examples 1 to 7 showing the implementation details of the present invention All rates are over 95% at 160℃
We have secured a retention rate of over 94% in the supplementary exam. Also, the molecular weight stability according to cavilograph is 280℃.
This shows that the polymer exhibits almost no change in molecular weight within 1 hour, indicating that it is a highly stable polymer.

Comparative Example 1 Bisphenol #A228 was placed in a reactor with a stirrer and replaced with nitrogen.
．． 299 (10 mo/shi) and diphenyl carbonate 2
19.589 (LO25 mo) V), 9.91 q of phenyl benzoate (5 mo/L/% relative to bisphenol/L/-A) were added and melted at 160°C, and then the catalyst bisphenol/L 'A disodium salt bispheno-/L/A
10-mol% of K was added to start the reaction.

The temperature was gradually raised to 2701:1 over 3 hours, the reaction system pressure was also reduced to 1.01 nlH9, and the produced phenol was distilled off. Subsequently, at 270°C for 1 to 2 hours, α2 to 0.
A polymer was obtained by reacting with 1 flHiF. The viscosity average molecular weight of the obtained polymer was 16.300. The evaluation results of the obtained polymer are @'? #'vc showed.

The heat stability and hydrolytic stability are inferior to those of the examples of the present invention.

Comparative Example 2.3 Note 1 Bisphenol A polycarbonate was produced in the same manner as in Comparative Example 1 above using the catalyst end capper shown in Table i.

In particular, Comparative Example 3 is an example in which the alkyl group is replaced with a stearyl group and a long substituent is introduced in the alkyl-substituted benzoic acid phenyl ester as the terminal capping agent of the present invention, but there is a clear tendency to impair heat resistance stability. It's coming out.

(Effects of the Invention) The optical material polycarbonate resin obtained from the present invention has high fluidity and is excellent in heat resistance, hydrolysis resistance, melt viscosity stability, and molecular weight stability. It is useful for discs such as discs, video discs, and memory discs, lenses, and elements that transmit or reflect light.

Agent Patent attorney Takashi Koshiba Patent applicant Daicel Chemical Industries, Ltd. Procedural amendment (voluntary) 1. Indication of the case Patent Application No. 188180 filed in 1988 2. Name of the invention Process for manufacturing optical material polycarbonate resin 3. Amendments to be made Relationship with the patent applicant's case Postal code: 590 Address: 1 Teppo-cho, Sakai City, Osaka Prefecture> Claims column and detailed explanation of the invention column in the specification (1) The scope of claims is as shown in the attached sheet. Correction (1) From page 6, lines 19 to 20 of the specification to page 7, line 15 (X) 4
(X)4 is represented. In the formula, A is...
・m is 0 or 1. ”(Rx)c
(Rz)m-C- (wherein Y and Z are a hydrogen atom, a linear or branched alkyl group having 1 to 60 carbon atoms, or a phenyl group).

R1 and R2 each represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, and l and m each represent 1.
It is an integer of ~4. (1) Specification, page 11, line 8 [Correction of divalent phetol j to "dihydric phenol" α '') JK 2, Claims ``Polycarbonate produced by transesterification from dioxy compound and diallyl carbonate In producing , at least one catalyst selected from alkali metal borohydride, tetraalkylammonium polyhydride, and tetraalkylammonium halide is used as a catalyst, and as a terminal capping agent and a molecular weight regulator, a compound represented by the following general formula is used. A method for producing polycarbonate resin, an optical material, characterized by terminal modification using a monofunctional organic compound.

general formula

Claims (1)

[Claims] In producing polycarbonate from a dioxy compound and diallyl carbonate by transesterification reaction, at least one catalyst selected from alkali metal borohydride, tetraalkylammonium polyhydride, and tetraalkylammonium halide is used as a catalyst. A method for producing an optical material polycarbonate resin, characterized in that terminal modification is performed using a monofunctional organic compound represented by the following general formula as a terminal stopper and a molecular weight regulator. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R represents hydrogen or a linear or branched alkyl group having 1 to 12 carbon atoms.)