Claims
- 1. A process for preparing a polycarbonate comprising melt-polycondensing (A) at least one dihydric phenol with a co-monomer selected from the group consisting of (B) bisphenyl carbonate, (C) bis(2,4,6-trichlorophenyl) carbonate, (D) bis(2,4-dichlorophenyl) carbonate and (E) bis(2-cyanophenyl) carbonate in the presence of a catalyst selected from among electron-donating amine compounds or salts thereof, with the proviso that said salt is other than a chloride.
- 2. The process as claimed in claim 1, in which (A) is at least one member selected from the group consisting of (I), (II), (III) and (IV): ##STR2## in which R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are hydrogen or an alkyl having 1 to 8 carbon atoms and being either straight or branched or phenyl, X is a halogen, n is a number of zero to 4 and m is a number of 1 to 4.
- 3. The process as claimed in claim 1, in which the catalyst is present in an amount of 10.sup.-1 to 10.sup.-5 mole per 1 mole of the dihydric phenol.
- 4. The process as claimed in claim 1, in which the catalyst is present in an amount of 10.sup.-1 to 10.sup.-3 mole per 1 mole of the dihydric phenol.
- 5. The process as claimed in claim 2, in which the monomer (A) comprises two or more members selected from the group consisting of (I) to (IV).
Priority Claims (3)
| Number |
Date |
Country |
Kind |
| 1-31904 |
Feb 1989 |
JPX |
|
| 1-161039 |
Jun 1989 |
JPX |
|
| 1-279048 |
Oct 1989 |
JPX |
|
PRIOR ART
This application is a continuation-in-part of U.S. patent application Ser. No. 07/423 336, filed Oct. 18, 1989.
The present invention relates to a process for preparing a high-molecular polycarbonate prepared by melt-polycondensing a dihydric phenol or a hydroxy compound with bisphenyl carbonate or another substituent-having bisphenyl carbonate in the presence of an electron-donating amine compound catalyst or salts thereof.
The high-molecular polycarbonate of the present invention is a general purpose engineering thermoplastic which can be used in wide applications, particularly in injection molding or as a glass sheet instead of a window glass. Interfacial polycondensation is generally effective in producing polycarbonate but has drawbacks that toxic phosgene should be used and chloride ions remain in the formed polycarbonate. In order to eliminate these drawbacks, Japanese Patent Laid-Open No. 182336/1988 discloses production of a polycarbonate through interfacial polycondensation of a particular dihydric alcohol with liquid trichloromethyl chloroformate used instead of toxic phosgene. However, only 9,9-bis(4-hydroxyphenyl)fluorene is described as the particular dihydric phenol. Angew. Chem., 99, 922 (1987) describes that a polycarbonate is prepared from 2,2-bis(4-hydroxyphenyl)propane by making use of triphosgene instead of toxic phosgene. However, it also describes a reaction mechanism by which phosgene is generated.
In the invention a polycarbonate is produced by melt-polycondensing (A) a dihydric phenol, or a hydroxy compound, with a co-monomer selected from the group consisting of (B) bisphenol carbonate, (C) bis(2,4,6-trichlorophenyl) carbonate, (D) bis(2,4-dichlorophenyl) carbonate and (E) bis(2-cyanophenyl) carbonate in the presence of a catalyst selected from among electron-donating amine compounds and salts thereof. The process of the invention saves the use of phosgene which is poisonous and prevents the resulting polycarbonate from incorporation thereinto of chlorine ions.
The dihydric phenol (A) is preferred to be one of those having the following formulae (I), (II), (III) and (IV): ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each hydrogen, a straight-chain or branched alkyl group having 1 to 8 carbon atoms, or a phenyl group, X is a halogen atom, n is 0 to 4, and m is 1 to 4.
Representative examples of the electron donating amine compound which may be used in the present invention include N,N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 4-pyrrolidinopyridine, 4-(5-quinolyl)-pyridine, 4-aminopyridine, 2-aminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 4-hydroxypyridine, 2-dimethylaminoimidazole, 2-methoxyimidazole, 2-mercaptoimidazole, 2-aminopyridine, aminoquinoline, imidazole, 2-methylimidazole, 4-methylimidazole, diazabicyclooctane (DABCO), etc.
In the present invention, the electron donating amine compound can be used in the form of a salt in which the counter ion is an acid including, for example, carbonic acid, acetic acid, formic acid, nitric acid, nitrous acid, oxalic acid, sulfuric acid, phosphoric acid, fluoroboric acid and hydroboric acid. Chlorides of the electron donating amine compounds are excluded from the scope of the present invention.
Representative examples of the dihydric phenol include the following compounds. Examples of the bisphenol represented by the general formula (I) include 2,2-bis-(4hydroxyphenyl)propane, 2,2-bis-(4-hydroxyphenyl)butane, 2,2-bis-(4-hydroxyphenyl)-4-methylpentane, 2,2-bis-(4hydroxyphenyl)octane, 4,4'-dihydroxy-2,2,2-triphenylethane, and 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)propane. Examples of the bisphenol represented by the general formula (II) include 2,2-bis-(4-hydroxy-3-methylphenyl)propane, 2,2-bis-(4-hydroxy-3-isopropylphenyl)propane, 2,2-bis-(4-hydroxy-3-secbutylphenyl)propane, 2,2-bis-(3,5-dimethyl-4hydroxyphenyl)propane, and 2,2-bis-(4-hydroxy-3-tertbutylphenyl)propane. Examples of the bisphenol represented by the general formula (III) include 1,1'-bis-(4-hydroxyphenyl)-p-diisopropylbenzene, and 1,1'-bis-(4-hydroxy-opropylbenzene. Examples of the bisphenol represented by the general formula (IV) include 1,1-bis(4-hydroxyphenyl)cyclohexane. Further, it is also possible to prepare a copolycarbonate through a combination of at least two dihydric phenols selected from among those represented by the general formulae (I), (II), (III) and (IV).
The method according to the present invention can be practiced by melt-polycondensing a dihydric phenol, such as bisphenol A, with bisphenyl carbonate in the presence of a catalyst selected from among electron-donating amine compounds.
This reaction is conducted at a temperature in the range of 100.degree. to about 300.degree. C., preferably 130.degree. to 280.degree. C. When the temperature is below 130.degree. C., the reaction rate is reduced, while when the temperature exceeds 280.degree. C., a side reaction tends to occur.
The electron-donating amine compound used as a catalyst should be used in an amount of 10.sup.-1 to 10.sup.-5 mol, preferably 10.sup.-2 to 10.sup.-4 mol, based on the dihydric phenol present in the reaction system. When the amount is less than 10.sup.-5 mol, the rate of polymerization of polycarbonate is reduced because of poor catalytic action. On the other hand, when the amount is more than 10.sup.-1 mol, the proportion of the catalyst remaining in the resultant polycarbonate is increased, which brings about a lowering in the properties of the polycarbonate.
Bisphenyl carbonate should be used in an equimolar amount to the dihydric phenol. In general, in order to form a high-molecular polycarbonate, 1 mol of a carbonate compound should be reacted with 1 mol of a dihydric alcohol. When bisphenol carbonate is used, 2 mol of phenol is formed by the above-described reaction. The 2 mol of phenol thus formed is distilled away outside the reaction system.
When the co-monomer is one of (C), (D) and (E), it is preferable that m is 1 in the formula (II) for the first monomer (A), the reaction is conducted at a temperature ranging from 130.degree. to 250.degree. C., an amount of the catalyst ranges from 10.sup.-1 to 10.sup.-3 mole.
US Referenced Citations (1)
| Number |
Name |
Date |
Kind |
|
4286085 |
Jaquiss et al. |
Aug 1981 |
|
Continuation in Parts (1)
|
Number |
Date |
Country |
| Parent |
423336 |
Oct 1989 |
|
Patent Grant
5025083
